Abstract:With the development of unmanned aerial vehicle (UAV) platforms and multispectral sensors, the application of multispectral remote sensing in light and small UAVs is becoming more and more extensive. Unmanned aerial vehicle remote sensing platforms equipped with different sensors have recently become an important approach for fast and non-destructive data acquisition and have the advantage of flexible and convenient operation, on-demand access to data and high spatial resolution. It has shown great potential in the fields of agriculture, forestry, ecology, environmental protection and so on. Firstly, this paper summarizes the main flight platform and the multispectral camera hardware technology. Secondly, the geometric and radiometric calibration of UAV multispectral image data processing technology are summarized. Thirdly, UAV multispectral remote sensing applications are systematically analyzed and summarized. Finally, some existing problems of the current UAV multispectral remote sensing system and the direction of development are proposed, in order to provide a reference to the related research. With the continuous progress of UAV based multispectral hardware technology, combined with the increasingly mature image processing and analysis software, the accuracy and ease of use of UAV multispectral remote sensing system will be improved. We suggest that practitioners from all sectors of the industry work closely with experts in remote sensing and computer science to develop and popularize multispectral remote sensing technology for unmanned aerial vehicles.

Abstract:The greenhouse plug seedlings transplanting machines applied to industry are mostly with three-dimensional gantry structure. There are some obvious shortcomings like large size and inertia, low relatively rigidity, high prices and poor flexibility in operating capacity and not suitable for filling the gaps with seedlings or rejecting seedlings in high-speed operation. In view of these problems, it was intended to design a transplanting machine system with main body of parallel mechanism. The main structure of parallel transplanter and its five kinds of end effector of matching design were introduced. And then the quality of these end effectors was calculated. First of all, the rigid-flexible coupling multi-body dynamics model of parallel mechanism was established in ADAMS. Secondly, a longest diagonal trajectory was picked for simulation, and the error between the theoretical trajectory of the rigid model and the actual trajectory of the flexible model was compared. And then, the influence of changes of mass to motion error was set and explored by rigid-flexible coupling multi-body dynamics simulation in ADAMS and the feasibility of the parallel design was verified. It was found that there was oscillation at the end of the transplanting track. Finally, the positioning accuracy was tested by the physical prototype. Position error of the moving platform to each point was counted and the control system was compensated. It was turned out that the average positioning error was reduced from 7.611mm to 1.208mm. And most of the errors were systematic errors. During working process, the transplanting machine was with low deformation and high accuracy in taking and delivering stage during acceleration peak was 20m/s2 and average speed was 2m/s. But when the average speed was 3m/s and the acceleration peak was 30m/s2, the error was increased and the radial support force needed to be improved.

Abstract:In order to obtain the quality of peanut seedling rapidly and accurately, a method based on machine version was put forward to evaluate the quality of peanut seedling. Firstly, a field walking robot was developed which can ensure the robot accurate moving automatically and keep a constant speed. The peanut image information was achieved by the camera configured on the robot, and the picture coordinate information was recorded by global position system. The number of peanut seedlings, canopy projection area of peanut seedlings and the coordinate position of peanut root was achieved based on machine vision. Secondly, the evaluation index of seedling quality was purposed, including the peanut seedling deficiency rate and peanut vitality index. The peanut seedling deficiency rate was calculated by the number of peanut seedlings and the coordinate position of peanut root, and the peanut vitality index was computed by the canopy projection area of peanut seedlings. In order to obtain the peanut number and its canopy projection area, a fast and accurate recognition method of peanut based on image adaptive classification algorithm was purposed. Peanut seedling extraction operator was proposed to enhance the robustness, and the K-means clustering method was used to automatically determine the optimal threshold for image segmentation, which avoided the environment disturbance and separated the peanut plants correctly. Then by using the global image segmentation combined regional image segmentation, the single peanut seeding was separated for farmland. Finally, the envelop area and its center position coordinates of each peanut seeding were obtained through image detection technology. Through data validation, the average recognition rate reached 95.4%, which indicated that the algorithm was feasible. Compared with the manual test, the average error of peanut seedling spacing was 5.35mm, and the correlation of peanut seedling deficiency was 0.991 (Pearson correlation coefficient). There was high consistency between manual and machine vision evaluation.

Abstract:In order to solve the problems of complex operation, heavy workload and toxic when measuring the grain volume by the existing pycnometer method, the research on accurate measurement of single grain volume draining method was carried out. Combining the image processing technology and the volumetric principle of the liquid draining method, the device was mainly composed of a standard white light source, a linear CCD, a measuring container, a cereal dedicated holding device, a computer and the like. Firstly, the standard white light source was adjusted, the image acquisition environment was enhanced, volume calibration was performed, and the actual volume value V0 was calculated, which was about 0.0023mL represented by a single pixel. Secondly, the liquid level image of measuring vessel was aquired by high accuracy linear CCD camera. Finally, the difference method was used to extract the image of the liquid level change;the number of pixels contained in this part of the image was counted, combining with the volume calibration results to calculate the volume value. Volume draining method and pycnometer method were used for the same batch of cereals respectively. Two sets of volume data were then obtained. Volumetric discharge took 12min, and pycnometer method took 124min. The two groups of data were tested by using the Grubbs test, F test and t test for significant differences tests, and the calculated test values were (TA,TB), FAB, tAB. The values were compared with the critical value of their distribution table: (TA,TB)<T0.05,100,FAB<F0.025(99,99), tAB<t0.05,198, and all of which met the inspection requirements. The results showed that there was no significant difference between the two sets of volume data. The accurate measuring device and method of volumetric discharge of single grain can quickly and precisely measure the volume of irregular single grain, and provide reliable grain volume for scientific research and actual production data.

Abstract:To improve the lower efficiency of silkworm cocoon harvesting, an algorithm of cocoon image segmentation and coordinate location was proposed based on color and area characteristics, and a cocoon harvestor was designed based on machine vision. The monocular CMOS camera was firstly used in the algorithm to take image of checker cocooning frame. And the non-measurement distortion correction method was used to correct the image. Secondly, the camera model was calibrated with the internal parameters for the monocular two-dimensional visual measurement system. The image was smoothed via gray and mean shift filter method because the outer floss of the cocoon can cause wrong segmentation of the image in checker cocooning frame image. Then the binary image was obtained by threshold segmentation. Next, the binary image was processed by open operation and area feature extraction method to remove noise region. A part of the smaller noise connected components can be removed by the open operation. The cocoon region can be extracted by the area characteristic when the large area of the connected components can be removed. The center point coordinates of the cocoon region were got by the connected components calibration, and were mapped into the world coordinates through the equation that transformed image coordinates to world coordinates to get the cocoons’ positions in the Cartesian space. Finally, the cocoons were harvested by the cocoon harvestor. According to the experiment, the algorithm had the accuracy rate of 96.88% for the cocoon detection in the checker cocooning frame and less than 6.0mm for the cocoon coordinate, which satisfied the requirement of the location of cocoon harvesting.

Abstract:Due to the varying degree of various pests’ damage, people tend to make some counter measures to protect the vegetables. Up to now, the most common method is to spray pesticides on vegetable pests. Farmers often lead to the excessive use of pesticides for lack of information about the number of pests. Traditionally, manual counting methods are carried out on the number of pests. It needs large labor costs, heavy workload, with subjective and other shortcomings, and using machine vision to monitor vegetable pests is a popular method recently. But the vast majority of current visual methods are to be carried out under the condition of ideal laboratory, which cannot be directly applied to pest monitoring in the field. Using visual perception technology to identify pests has become a hotspot in the field of agricultural engineering in recent years. Because of the shortcomings of the pests identification under the current field conditions, a new algorithm for counting the southern vegetable pests was studied by using yellow sticky trap. Based on the classical image processing algorithm, some new algorithms, including pest image segmentation sub-algorithm based on the structure of random forest, feature extraction sub-algorithm of irregular structure, background removal sub-algorithm, interference target removal sub-algorithm and detection model counting sub-algorithm were proposed. Those sub-algorithms were integrated to create a vegetable pest count algorithm based on visual perception (VPCA-VP). The images taken in the field environment were used for experimentation and analysis, and 9351 thrips, 202 whiteflies and 23 fruit flies were recognized. Compared with the artificial count, the accuracy rate of the vegetable pest counting algorithm based on visual perception was 94.89%. Among them, the accuracy rate of the thrip was 93.19%, the accuracy rate of the whitefly was 91% and the exact rate of the fruit fly was 100%. The algorithm had good performance and achieved the rapid counting demand, which had wide application prospect in farmland monitoring.

Abstract:Aimed at the problem of low breadth and uneven wheat sowing machine, a kind of wheat pneumatic centralized sowing system was designed. The sowing mechanism and distribution mechanism were studied from the aspects of concentrated quantitative seeding system and airflow first-order distribution system. The stability of the centralized quantitative seeding system and the uniformity of the seed distribution system were analyzed. Concentrated quantitative seeding system discharged a certain amount of seeds, and the seeds fell into the conveying tube in gravity. Airflow first-order distribution system converted the seeds into a uniform seed stream and transported to the seeding tube, which achieved uniform seeding requirements. According to the principle of distributor, the diameter of the conveying tube was 50mm. By the computational fluid dynamics (CFD) software Solidworks Flow, the influence of structural parameters of seed distribution system on vacuum chamber fluid were simulated and analyzed. The structural parameters included the conveying pipe and outer cover. The analysis of speed flow field showed that corrugated length of the fold tube was 16mm, corrugated angle of the fold tube was 90°, and cone angle of outer cover was 120°. The experiments of the uniformity and steadiness was designed and conducted for seeding distribution system. The performance tests were performed with four indices adopted, including variation coefficient of total displacement stability, variation coefficient of each row displacement consistency, seeding rate coefficient of variation of distributor intra-row, and the percentage of damaged seeds in laboratory. The results showed that when rotate speed of sowing device was in the range of 20~40r/min, variation coefficient of total displacement stability was 1.01%~1.19%, variation coefficient of each row displacement consistency was 3.20%, seeding rate coefficient of variation of distributor intra-row was 3.96%, and the percentage of damaged seeds was 0.23%. The test results were consistent with CFD simulation. The field experiment of sowing was also carried out with four indices, including the percentage of damaged seeds, variation coefficient of total displacement stability, variation coefficient of each row displacement consistency, and variation coefficient of seeding uniformity for this device. The results showed that variation coefficient of total displacement stability was 1.06%, variation coefficient of each row displacement consistency was 3.34%, variation coefficient of seeding uniformity was 27.35%, the percentage of damaged seeds was 0.28%, and the seeding emergence rate was 89.63%. These testing results fully coincided with the standard GB/T 9478—2005 Test methods of grain drills. The design and experimentation improved the seeding stability and distribution uniformity of the planter, and the results provided a theoretical reference for the design and analysis of wheat wide precision sowing.

Abstract:In order to improve the fertilization quality of deep fertilization for paddy field, an adjustable blades side deep fertilizing device for paddy field was designed. Structure parameters of fertilizer rate adjusting mechanism were optimized by using optimization software V1.0, which was developed for fertilizer rate adjusting mechanism of side deep fertilizing device for paddy field. The stress analysis was carried out for fertilizer rate adjusting mechanism, through which the output torque of stepper motor was determined greater than 680N·mm. Simulation model was established for adjustable blades side deep fertilizing device, and virtual experiment of distributing fertilizer was carried out by using discrete element EDEM software to analyze the acting force of fertilizer particle on spiral steel wire and hairbrush, therefore, the output torque of the direct current motor of fertilizer cases and anti-blocking device was determined greater than 5345N·mm and 8N·mm, respectively. Fertilization performance of groove wheel type and adjustable blade type side deep fertilizing device for paddy field were studied on JPS-12 type discharging seed performance detection test bench, through which the influence laws of the rotation speed and forward velocity of the groove wheel type side deep fertilizing device on fertilizer stability and uniformity were obtained, the influence laws of the opening diameter and the forward speed of adjustable blade type side deep fertilizing device for paddy field on fertilizer stability and uniformity were obtained. The test results showed that fertilizer stability and uniformity indexes of adjustable blade type side deep fertilizer device for paddy field can meet national standard requirements, the quality of fertilization was superior to that of groove wheel type side deep fertilizing device, and the fertilization ability can meet agronomic requirements.

Abstract:Aiming at the bottleneck problem that hinders the high-speed work development of mechanical seed-metering device, a kind of centrifugal cone direction push way for grain filling was proposed, the influence of the grain in the internal cavity filling properties of stress types and mechanical laws was analyzed, the composite filling stress mathematical model was established, the effective way to improve the filling force was found out through theoretical analysis, and the mathematical model was gradually dressed with the help of Matlab and ORIRIN drawing software to determine the optimal key structure parameters. Through the single bench test using discrete element simulation software EDEM virtual simulation of centrifugal push structure, and the cavity structure of centrifugal cone disc metering device were tested, the superiority of additional centrifugal push structure was demonstrated, test results showed that in the 7~13km/h high speed operation, the average leakage sowing index of Indus cavity structure cone disc metering device was reduced by 2.52%, at the same time, the postprocessing function measured marker granule filling variation and numerical prediction value basically had the same trend, which verified the feasibility of the theoretical model, maximized the play of a layer of centrifugal force on the pre filling grain, and to further expand the effective filling area, the study provided theoretical basis and reference for the centrifugal cone type highspeed exhaust device design and development.

Abstract:As the requirement advances for improving the working efficiency of mechanized application and the utilization rate of fertilizer, a variable-rate fertilizer spreader with centrifugal distribution cover for rice paddy surface fertilization based on the spectral sensor (Green SeekerTM) was developed to implement regional real-time variable-rate fertilization during rice growth period combining with the agronomic characteristics of rice fertilizer and near-earth spectroscopy. Spectrum detection device, decision-making and control system, variable-rate actuator and some other key techniques were designed, feedback system based on core controller STM32F103 was set up, and target application rate was responded united with expert fertilization strategy. Three-factor and three-level orthogonal performance test was carried out with setting feed gate flow rate A, disc rotational speed B and machine ground speed C as the influence factors, particle distribution coefficient of variation Cv and relative error of application rate γ as the evaluation index. By the orthogonal test, it can be known that the importance order of the factors which affected the Cv was A, B and C, and that affected the γ was B, A and C in the target spreading swath width, the comprehensive choice optimum combination of working parameters was A2B2C2, with q=300g/s, n=600r/min, v1=1.2m/s, and Cv=13.82%, and γ=9.54%, the fertilizer spreader reached the best working performance. Field tests under optimum combination showed that the average error of Cv and γ was 9.19% and 9.25%, respectively, compared with performance test. The performance of the developed variable-rate fertilizer spreader with centrifugal distribution cover was perfect and satisfied the requirement of uniformity of fertilizer and accuracy of application, which improved the performance of the centrifugal variable-rate fertilizer applicator, and it can provide certain theoretical basis for the traditional empirical fertilization.

Abstract:In the northeast ridge area，the stubble treatment and subsoiling operation before planting can improve the quality of seeding and promote the growth of crop. In the process of operation，available machines for subsoiling and stubble-breaking exist some problems，including the large amount of soil disturbance，the not ideal effect of stubble cleaning and stubble-breaking roller is easy to tangle with grass etc. At the same time，in order to adapt to the technology mode of conservation tillage in the northeast cold，and meet the agronomic requirements of ridge deep loosening stubble, a type of subsoiling and stubble-breaking machine was designed, of which the structure of stubble-breaking parts，subsoiling component and ridge forming parts were designed. Also，the field experiments were carried out to study the structure and operating parameters affected the machine. The influence factors of field experiment included the speed of working machine，the depth of stubble-breaking and the sliding cutting angle of sidelong edge for stubble-breaking blade. Evaluation indices included the rate of stubble-breaking and the depth stability coefficient of stubble breaking. The results showed that when the speed of working was 2.8km/h，the depth of stubble-breaking was 84.9mm，the sliding cutting angle of sidelong edge for stubble-breaking blade was 6.5°，the rate of stubble-breaking was 93.26%，the depth stability coefficient of stubble breaking was 95.25%. The stubble-breaking effect of stubble-breaking machine was ideal，which met the quality requirements in working.

Abstract:According to the problems of field plastic film pollution with film mulching of double rows on a big ridge cultivation pattern of potato in northwest arid area of China, the canvas belt combined operation machine for potato harvesting and plastic film collecting was designed, which had synchronous implementation function of potato harvesting and plastic film collecting. Based on design and calculation analysis of key operation parts for prototype, the operation parameters of anti-twining device, canvas belt transporting film device and floating curl-up film mechanism were determined. The related experimental factors and their range of values were determined which affected the plastic film collecting ratio of the combined recovery machine. The Box-Behnken experimental design with four factors and three levels was performed, the mathematical models between the key parameters such as operation machine speed, film-curling driving roller rotating speed, transporting film axis rotating speed, transporting film sheet dip angle and plastic film collecting ratio were established, and then the effects of various parameters and their interactions were analyzed as well. The test results showed that effects order of four parameters on the plastic film collecting ratio were as follows: film-curling driving roller rotating speed, operation machine speed, transporting film axis rotating speed and transporting film sheet dip angle. The optimal working parameters were combined operation machine speed of 0.72m/s, film-curling driving roller rotating speed of 303r/min, transporting film axis rotating speed of 499r/min and transporting film sheet dip angle of 29°. Confirmatory tests showed that the average value of the plastic film collecting ratio was 92.1%, compared with before the optimization it was dropped significantly. At the same time, under the operating parameters the obvious ratio of potato was 96.6% and the injury ratio of potato was 2.2%, which were up to the relevant work quality evaluation specification requirements.

Abstract:In order to study the influence discipline of parameters of gripping and delivering device (GDD) for corn harvester for reaping both corn stalk and spike in the cramping-cutting-transporting type on corn harvesting performance, the working principle of GDD was analyzed. Box-Benhnken design （BBD） response surface method was used to design the field experiments. An orthogonal rotary combination experiment was conducted with the angle of gripping chain, the teeth number of sprockets in enter shaft, the horizontal distances between reciprocating cutter and the nip point of gripping chains and the working speed of corn harvester as four independent factors, as well as loss rate of corncobs, maximum offset of x axis and y axis as three dependent indices, while using Zhengdan corn as the test materials. The height of 1.2m in corn straw was signed by colorful paper tape. And high speed cameras were utilized to record the motion of mark point. ProAnalyst motion analysis software was applied to get the maximum offset of x axis and y axis. Design-Expert software was employed to analyze the test results, mathematical equations between independent and dependent factors were gained. The results indicated that four independent variables had a second nonlinear relationship with loss rate of corncobs and maximum offset of x axis, and the horizontal distance between reciprocating cutter and the nip point of gripping chains had the greatest influence as well as the angle of gripping chain had the least effect, respectively. The four factors had no significant difference in maximum offset of y axis. The interaction of factors only had significant effect on loss rate of corncobs. At the angle of gripping chain of 19.96°, the teeth number of sprockets in enter shaft of 22.09, the horizontal distances of 22.33mm as well as the working speed of corn harvester of 1.31m/s, the GDD showed optimal performance with loss rate of 0.4% and maximum offset of x axis of 24mm. Field verification test was carried out after the combination of the optimal parameters, and the results showed that the regression model had good reliability to predict the loss rate of corncobs and maximum offset of x axis. According to comparison of transplanting performance before and after parameter optimization, loss rate of corncobs was reduced by 2.4 percentage points, which was superior to the technique indexes of national and industry standards as well. The research provided a basis on the design of gripping and delivering device of corn harvester for reaping both corn stalk and spike.

Abstract:The problem of residual film pollution is serious in the cotton fields of Xinjiang, and the mechanical recycling of residual film is the main recycling method. In the existing residual film recycling machines, spring tine or telescopic rod tine film producing device are commonly used, thus the phenomenon that residual film winds work piece is prone to occur, affecting the effect of film producing and removal. In view of the above problems, a sprocket conveying residual film recycling machine of casting film with film producing throwing, sprocket conveying and automatic film stripping was designed according to the advantages of the existing models based on the principles of planer cylinder knife film producing and casting film cylinder knife throwing. The machine was mainly composed of film-producing device, conveying device, film stripping device, transmission system and film collecting box. The residual film by throwing up film with chain gear conveying realized the separation of residual film and film clod, ensured the reliability of automatic stripping, and the scraper stripping mechanism to complete unloading film, plastic film, solved the difficult problem of removing film winding. The results of the field experiment showed that when the operating speed was 4~7km/h, the average value of the recycling rate of residual film was 90.6%, the average value of working efficiency of the machine was 0.84hm2/h, and the average value of impurity rate of residual film was 3.971%. When the operating speed was fast, the working efficiency was improved, but the recycling rate was reduced, and the impurity rate was increased. When the operating speed was 5km/h, the average value of the recycling rate was 91.8%, the working efficiency was 0.733hm2/h, and the average value of impurity rate was 2.605%, so it was more suitable operation speed. The machine was operated well, which had good effects of film producing and stripping, and it can be used for the recycling of residual film in the cotton fields of Xinjiang, it can also provide design reference for residual film recycling machine.

Abstract:In order to solve the problem of high altitude picking difficulty, improve the picking efficiency and reduce the cost of picking, according to the test results of the separation of pecan fruit and tree branches, a portable pecan artificial high-altitude pat-picking device was designed. The key parts of the picking machine were mainly introduced, the establishment and calculation of the mathematical model were carried out for the mining mechanism, ADAMS was used to simulate for mining mechanism, the mechanism and working parameters of the mining mechanism were determined, which provided the basis for the design of picking machine, and the prototypes were made. Pecan picking experiment was carried out, the results indicated that the net rate of fruit picking had a significant effect at P=0.05, the net rate of fruit picking was increased gradually with the frequency of slapping, when slapping frequency peaked at 13.33Hz, the net rate of fruit picking was 90.3%, which had less bud damage, but the faster the flapping frequency was, the more obvious the damage was to the bud, therefore, the average net rate would reach 85.1%~90.3% when flapping frequency was recommended to be 10~13.33Hz, and no destructive damage to bud.

Abstract:Aerobic deterioration of bale silage due to puncturing plastic cover by accident or feeding animals results in the nutrition and energy losses. The invasive oxygen that activates the aerobic microorganism to consume nutrition in silage, producing heat that raises the silage temperature, is a key factor being in charge of aerobic deterioration of silage. However, thus far, the in-situ sensing and modeling the dynamics of oxygen diffusion and temperature rising in bale silage has seldom been reported. For this, a Clark-electrode-based dissolved oxygen sensor was applied for in-situ measurement of oxygen concentration and temperature in bale silage. Based on the measurement data, a mathematical model coupling two-dimensional oxygen diffusion, microorganism growth and temperature rising was presented and validated. The tested grass silage was baled by using a baler from CLAAS company (Baler type: Rollant455) with two levels of dry matter contents (DM-1：39.0%±1.3%;DM-2：31.4%±2.1%). Each level had three replications. The results showed that the model simulations generally agreed with the in-situ measurements. The uncertainties between measurement and simulation were mainly due to the heterogeneity of silage density distribution. Moreover, a great quantity of water produced during aerobic deterioration changed the parameters in model such as decline of the diffusion rate of oxygen, increase of the heat capacity, resulting in lower predicting accuracy. Thus, the heterogeneity of silage density distribution and water-induced parameter variation should be included in proposed model for achieving higher predicting accuracy.

Abstract:The pressure pulsation and flow-induced noise of outlet conduit have become two of important problems which have negative effect on axial-flow pumping system reliability. In order to investigate the flow-induced noise and pressure fluctuation characteristics of outlet conduit in axial-flow pumping system under different operating conditions, the fluctuating pressure and noised signals were obtained by pressure transduces mounted at different positions and a hydrophone in middle of outlet conduit. The experimental data were further analyzed by using short-time Fourier transform method at speeds of 1450 r/min, 1800 r/min and 2200 r/min. The results showed that with the increase of rotational speed, the root mean square of the pulsating amplitude of each measuring point was increased in the same flow rate ratio. With the increase of flow rate ratio, the root mean square of pulsating amplitude was decreased for each measuring point at the same rotational speed, while there were differences in the dominant frequency of each measuring point in different flow rate ratios. The latter was adjacent to 51Hz for the same measuring point at different flow rate ratios with different rotational speeds. The dominant frequency and subdominant frequency were not multiple relation with rotational frequency. The dominant frequency and subdominant frequency was in the range of 200Hz. With the increase of rotational speed, sound pressure level of flow-induced noise was increased in the same flow rate ratio. With the increase of flow rate, the sound pressure level of flow-induced noise was decreased firstly and then increased at the same rotational speed. The rotational speed had great influence on sound pressure level of flow-induced noise under the optimal condition. The research result had reference value for study on pressure pulsation and flow-induced noise in outlet conduit of pumping system.

Abstract:To solve the problems occurring in surveying the farmland environment such as limited energy and different distances of communication among the nodes, a monitoring system with adaptive transmitting power for rice fields based on received signal strength indication (RSSI) and packet loss rate (PLR) was designed and a long-time, stable and highly reliable wireless sensor network (WSN) running this algorithm with low power consumption was established. In the aspect of hardware, to extend the network coverage and improve the stability of the system, the method of frequency heterogeneity was adopted to cluster the nodes and configure different antennas for different nodes. In the aspect of software, the mini embedded free real-time operating system (FreeRTOS) was selected to improve the utilization of CPU and prolong the working life of the clusters. Additionally, to reduce the power consumption, the mode of timed sleeping and waking as well as the power-down control of sensor were selected as the working pattern and the adaptive low-power-consumption mechanism were used on the basis of data deviation perception. The result of tests showed that the system can adaptively adjust the transmitting power to the minimum value which can meet the demand of the stability of communication (PLR was less than 1.3%) within the communication distance of 150m according to the quality of current communication. In this situation, when the algorithms of adaptive transmitting power was adjusted to 8dBm, 6dBm and 3dBm, respectively, from 10dBm, the battery duration of nodes was increased by 11.9%, 21.4% and 33.3%. As the result revealed, the communication performance of the nodes was significantly better than those of three other nodes with different adaptive transmission power algorithms. Thus it can be seen that the system was highly stable and practical in the application of WSN for the monitoring of farmland environment.

Abstract:Large scale management of spatial distribution of oilseed rape is essential for grain yield estimations, ensuring edible oil supply and sustainable agricultural management. Flowering period is the special growth stage of oilseed rape. Spectral feature of oilseed rape in this period changes largely. Furthermore, the sense of sight for oilseed rape also has a big difference against with other vegetation types during flowering period. Thus, spectral feature and color feature in the flowering stage can be set as the unique features for identifying oilseed rape as well as the basis of oilseed rape extraction. NGVI, a flowering-contained detecting indicator, was used to represent spectral feature of oilseed rape in the flowering period. H, S and V components were conducted as color feature of oilseed rape after processing colorimetric transformation from RGB color space to HSV color space. And then, the samples of oilseed rape and non-oilseed rape, which were interpreted on wide field view (WFV) images from Gaofen satellite no.1 (GF-1) combined Google Earth images and field investigation, were analyzed to determine the thresholds of NGVI, H, S, and V successively. Afterwards, oilseed rape in Hubei Province of China in 2016 was extracted based on GF-1 WFV images that obtained in full-flowering stage, which was evaluated by confusion matrix and compared with traditional support vector machine (SVM) method. Meanwhile, the GF-1 WFV-estimated planting acreage of oilseed rape was validated against agricultural census data. As a result, the sample evaluation achieved 94.51% of overall accuracy and 0.89 of Kappa coefficient, which improved four percentage points and 0.1 compared with SVM method, respectively. The result against statistical data had -14.14% of relative error at provincial level as well as 0.837 (n=17) and 0.738 (n=83) of decision coefficients at municipal level and county level. Moreover, the method was applied on panchromatic and multi-spectral (PMS) image from GF-2 and validated by reference oilseed rape map. The relative error of oilseed rape extraction was -8.33% and spatial consistency was 91.67%. Therefore, this study proposed a simple, effective and robust oilseed rape extraction strategy in large-regional scale based on satellite imagery of full-flowering period.

Abstract:In order to achieve nondestructive detection of heavy metal cadmium in lettuce leaves, computer vision technology was used as the research method, which combined image processing method and feature selection method, to identify four gradients of heavy metal cadmium stress lettuce leaves. First of all, the leaf image of lettuce was obtained by digital camera. Then, the Kmeans clustering algorithm was used to segment the image, and the color, shape and texture of the image were extracted from the extracted target image. A total of 46 image features were obtained. In order to make the model easier and reduce the amount of data, the image feature was dimensioned by competitive adaptive reweighted sampling (CARS) and variable importance analysis based on random variable combination (VIAVC). The partial least squares discriminant analysis (PLS-DA) and random forest (RF) were used to construct the model for identification of cadmium stress in lettuce. The results showed that in the seven combined feature models, the optimal model was given by the model of color, shape and texture fusion. The accuracy of the training set classification was 92%. The color, shape and texture fusion features were reduced by CARS and VIAVC, and it was found that the dimensionality and visualization of VIAVC were better than those of CARS. Using the reduced dimension of the lowdimensional mapping point to build the model, the accuracy of the training set classification and accuracy of the prediction set of RF model were higher than those of the PLS-DA. Among them, the accuracy of the training set and predictive set classification based on VIAVC dimensionality reduction were 98.0% and 96.0%, respectively. It can be seen that the RF model based on VIAVC dimensionality can better identify the lettuce leaves with different cadmium stress levels under the premise of greatly reducing the feature dimension.

Abstract:In order to detect the moisture content of maize leaves quickly and nondestructively, a portable plant leaf moisture detector was developed based on near infrared spectroscopy and wireless sensor network. The structure was designed according to the principle of transmission spectrum. The device could be divided into data acquisition node and data receiving node. And the ZigBee network was used to transfer the data between them. There were three modules in the data acquisition node, including a signal acquisition module, a signal processing module and a signal transmission module. The data acquisition node mainly completed the acquisition, amplification and filtering of the spectral data, and then sent it to the PDA through the master chip JN5168. The data receiving node was designed with a data receiving module and a PDA. The signal acquisition module was the key component with a light source and a sensor. The active LED lights in near-infrared band (890nm and 980nm) sent light, and the PIN type photodiode was used to measure the transmission signal. After the signal amplification and filtering, it was sent to the data receiving node by the ZigBee network. The parameters were calculated, including T890, T980, ratio vegetation index (RVI), modified normalized difference water vegetation index (MNDWI) and so on. The field test was conducted. The correlation between the parameters and water content was analyzed. The best application location of maize leaves was recommended. The results showed that the best detecting range was 70%~80% and the resolution was 0.3%. The detection model was established by T890, T980 and MNDWI, with R2C=0.854, R2V=0.849, and root mean square error of 0.0103. It could help to detect leaf moisture content nondestructively in the field.

Abstract:In the early stage, pig cough sound could be detected for early disease warning, and a method based on deep belief nets (DBN) was proposed to construct a pig cough sound recognition model. Pig sounds of Landrace pigs, including cough, sneeze, eating, scream, hum and shaking ears sounds were automatically recorded. The samples were preprocessed by speech enhancement algorithm based on a psychoacoustical model and speech endpoint detection algorithm based on short-time energy to reduce the noise and get useful parts of samples. Based on the dynamic time warping (DTW) algorithm, the short-time energy characteristics were scaled to a 300-dimensional short-time energy feature vector, while the 24-dimensional MFCC characteristics were scaled to a 720-dimensional MFCC feature vector. And then the 300-dimensional short-time energy feature vector and the 720-dimensional MFCC feature vector were combined to construct a 1020-dimensional vector as the input of the deep belief nets. The number of neuron of the three hidden layers were set to be 42, 17 and 7, respectively, so the pig sound recognition model based on DBN was finally designed to be 1020-42-17-7-2. The 5-fold cross validation experiment showed that recognition rate, error recognition rate and total recognition rate of the best experimental group were 94.12%, 7.45% and 93.21%, respectively. Furthermore, the first 479 principal components of 1020 dimension feature parameters were obtained by PCA dimensionality reduction. The recognition rate, error recognition rate and total recognition rate obtained better performance, and the best experimental group reached 95.80%, 6.83% and 94.29%, respectively. The result demonstrated that the DBN model was effective for the pig cough recognition.

Abstract:In order to overcome the problems of manual livestock body size measurement which is labor intensive, time consuming and stressful to the animals, a livestock body size measurement method based on the mirror reflection of single angle point cloud was proposed. A single depth camera Xtion was utilized to capture the sequences of point clouds of the scene, including pig and point clouds were stored in the computer, and then the scene point cloud, including the pig that bending degree of its back was not large was selected manually. Subsequently, the ground of the scene was deleted by using random sample consensus, the remaining scene point cloud was segmented based on Euclidean clustering, and then all the clusters were sorted according to the distance from the center of cluster to the coordinate origin, and the smallest one was extracted as the target pig. Pose normalization of the extracted pig was obtained by using a PCA based approach. Then, the pig symmetry plane was detected from the single angle point cloud by using the prior information of pig after pose normalization. Using the symmetry plane, the point clouds data of whole body surface of pig was obtained. Finally, by using the software developed by the institution of the authors, body size measurement was performed manually. The results showed that the average relative errors were 5.00% for body length measurement, 7.40% for hip width measurement and 5.74% for hip height measurement. This method offered a new way to measure the livestock body size.

Abstract:China puts forward the major strategic deployment of constructing well-facilitied farmland vigorously to improve the overall production capacity of farmland and adapt to the development of agricultural modernization. The recognition of well-facilitied farmland is foundation of site selection before constructing and evaluation after constructing. The well-facilitied farmland was understood from the point of view of production demand and recognized based on the evaluation of farmland comprehensive quality. Firstly，the characteristics of farmland comprehensive quality was analyzed from a lot of angles, such as background condition, spatial shape, construction level, ecological protection and so on, by fusing the multi-source data and taking the farmland patches as the basic units. The description system of farmland comprehensive quality was built by using five characteristics, including soil productivity, land contiguous, field shape, road accessibility and ecological protection. Secondly, it assumed that these five characteristics were the same important for farmland comprehensive quality, so the weights were all made as 0.20 and the preliminary evaluation results were got by TOPSIS method. Thirdly, the true-value samples were acquired by using the combined method of preliminary evaluation results and man-machine interactive optimization. The man-machine interactive optimization was achieved by spatial overlay between the preliminary evaluation results and the farmland utilization grade from the farmland-grading work in China. And then BP neural network was used to fix the feature weights. Fourthly, the final accurate comprehensive quality evaluation results were got and the recognition of the well-facilitied farmland was achieved. Finally, Daan City in Jilin Province was taken as the study area. The research results showed that the accuracy of the method to evaluate farmland comprehensive quality was above 96%, basing on the multi-characteristic description system. The well-facilitied farmland was widely distributed in the study area. The well-facilitied farmland mainly concentrated in northeast, north, edge of northwest and part of the southern region. These regions had the advantage of agricultural modernization, such as concentrated farmland, villages, roads and forest. The well-facilitied farmland which was registered with the law and the prospective high-quality farmland which was not registered with the law were both recognized effectively. The above result had strong consistency on the spatial distribution with the preliminary evaluation results, but the former refined the comprehensive quality results of partial farmland based on the relative importance of each characteristic. The research result can provide scientific reference and technical support for regulation, protection and construction of well-facilitied farmland.

Abstract:Based on the data of newly increased cultivated land from 2013 to 2015 at the district and countylevel in Beijing-Tianjin-Hebei region, the whole feature of the newly increased cultivated land, the feature of different types newly increased cultivated land were explored, and the newly increased cultivated land was analyzed from the perspective of different sources indepth. The research methods included gravity center model, Ginicoefficient, geographic concentration and some methods of statistical analysis. Research results showed that from 2013 to 2015, all of the new cultivated land in the Beijing-Tianjin-Hebei region was mainly concentrated in the middle east plain, western mountainous areas and the northern plateau areas. Analyzing the newly increased cultivated land in different years, the area of the newly increased cultivated land in Beijing-Tianjin-Hebei region was decreased first and then increased;the gravity center was transferred from northeast to southwest. And the newly cultivated land was highly concentrated. Gry land was mainly cultivated land types in Beijing-Tianjin-Hebei region, but the newly increased irrigated land was mainly newly increased cultivated land type. The largest proportion was land consolidation’s newly increased cultivated land in rural. The main source of the newly increased cultivated land was grassland, so that ecological problems were becoming more prominent. On this basis, reasonable suggestions were put forward for Beijing-Tianjin-Hebei region in the future land remediation work. It was suggested that the Beijing-Tianjin-Hebei project should adjust measures to local conditions in the future, increase water efficiency, and pay attention to the construction of ecological civilization.

Abstract:The study on the structure of complex space ecological network with spatial attribute information is a blank of the current research on complex network. Dengkou County, a typical county in the desert oasis area, was selected as the study area. The method of point pattern analysis in complex network analysis methods, the algorithm of extracting network skeletons and the robustness index of spatial structure were modified in accordance with the characteristics of the actual spatial ecological network, to analyze the structure of spatial complex ecological network in the study area. The results showed that the nodes of seven types of eco-sources exhibited aggregated spatial distribution pattern at a small scale, which was gradually distributed randomly as the scale increase, and finally distributed uniformly. This distribution feature ensured that ecological networks were stable at both small and large scales. The NDVI and MNDWI values of different types of ecological source had different distribution characteristics. The density of water corridors was ranged from 0 to 1.46, and the density of road corridors was ranged from 0 to 2.27. The framework corridor identified by Kruskal algorithm combined with the ecological network features was in accordance with the actual situation. The initial robustness of the current ecological network was only 0.73, and the robustness of the ecological network after optimization reached 1. Malicious attacks were more destructive than random attacks, but the optimized ecological networks showed stronger antistrike capability, stronger connectivity and stronger robustness of node and edge recovery. After optimization of the ecological node layout, the ecological network nodes and edges were more resistant to attack and destruction and more resilient.

Abstract:The BRT_Dyna-CLUE_Patch-dynamics model was formed by improving Dyna-CLUE model, by embedding BRT model and Patch-dynamics model. Based on the landuse situation in Dengkou County in 2006, a case study was conducted in Dengkou County, a typical county in the ecologically fragile region. The BRT_Dyna-CLUE_Patch-dynamics model was used to simulate the landuse situation in 2016 in Dengkou County and compared with the Logistic_CA_Markov model which was currently used more. The results showed that the Kappa coefficient of the Logistic_CA_Markov model was 0.7214, and the Kappa coefficient of the BRT_Dyna-CLUE_Patch-dynamics model was 0.7826. The simulation results of the two combinatorial models were highly accurate and both were highly consistent with the real interpretation results. BRT_Dyna-CLUE_Patch-dynamics model had high simulation accuracy and good result. Therefore, it is feasible to apply the BRT_Dyna-CLUE_Patch-dynamics model to the simulation and forecast of local landuse change in order to provide some reference for the implementation of local ecological control and related policies.

Abstract:The winter wheat was selected to study the effect of biochar of cotton straw on root morphology and endophytic fungal communities by using the method of root scanning and Illumina Miseq high-throughput sequencing. The symbiosis mechanism was found by the test. The treatments were amount of 4.5t/hm2, 9.0t/hm2 and 13.5t/hm2 of straw biochar, respectively applied to the soil, and the straw returning was taken as test control in the field experiment. The results showed that root diameter and specific root length were increased significantly, and branching density and biomass were decreased significantly in the primary root, and only the root branching density was decreased in the secondary root, when the amount of biochar was 4.5 ~ 13.5t/hm2 in the mature period of winter wheat. At the fungal phyla level, the abundance of Ascomycota was increased significantly, and the abundances of Zygomycota, Chytridiomycota and unidentified fungus was reduced greatly, and the abundance of Glomeromycota was not significant. At the common fungal order level, the abundance of Pleosporales was increased significantly, and the abundance of Eurotiales and Mortierellales was reduced greatly. With the amount of 4.5~9.0t/hm2 biochar promoted the primary root growth of root branch density and biomass by decreasing the abundance of Eurotiales, and inhibited the secondary root growth of diameter and branch density by increasing the abundance of Pleosporales. By comprehensive comparison, the effect of amount of 9.0t/hm2 biochar on root morphology was better than that of other treatments. The treatment with amount of 9.0t/hm2 significantly increased the primary root diameter by 5.00% and specific root length by 33.57%, and decreased root branch density by 67.26% and biomass by 27.27%, while also reduced the secondary root diameter by 13.16% and branch density by 34.38%, compared with the test control at maturity stage of winter wheat.

Abstract:In order to quantitatively analyze the issues on the mutual use of water and the mechanism of salt migration, clear the relative competitive between the two species of intercropping in wheat-sunflower intercropping system in Hetao irrigation area, the experiment was conducted based on root separation method. The results showed that in wheat-sunflower intercropping system, the wheat utilized 78.23~94.23m3/hm2 of water by the side of sunflower. Meanwhile, the sunflower utilized 44.96~57.97m3/hm2 of water by the side of wheat. By the cross superposition effect of soil internal space, more soil water of 18.56~42.84m3/hm2 and 20.79~46.63m3/hm2 in wheat and sunflower belts may be utilized, the mean value of root soil EC in wheat and sunflower belts could be reduced by 1.32%~4.64% and 2.26%~3.16%, respectively. By the water and nutrient complementarity effect of soil internal space, more soil water of 15.12~26.40m3/hm2 and 47.60~57.44m3/hm2 in wheat and sunflower belts may be utilized, the mean value of root soil EC in wheat and sunflower belts could be reduced by 2.98%~4.69% and 1.82%~2.44%, respectively. For the relative competitive ability between the two species in intercropping system, the wheat was stronger than sunflower, limiting the cross superposition effect and water and nutrient complementarity effect of root in intercropping system was conducive to upgrading the relative competitive ability between the two species of sunflower.

Abstract:Regulated deficit irrigation is through active exerting a certain degree of water stress artificially, exercising the crop drought resistance, affecting their physiological and biochemical process, in order to achieve the goal of saving water and increasing production. Taking maize as research object, the experiment was carried out in micro test pit area, and the influences on soil water distribution, root length, root length, root number, yield and crop water utilization efficiency were studied under drip irrigation on ground. Five different treatments (C1,C2,C3,C4 and C5) were set, which were slight and moderate regulated deficit in seeding and jointing stage, separately, and moderate regulated deficit in seeding stage while slight regulated deficit in jointing stage in 2016, and the whole growth period with suitable irrigation (CK) was set as control treatment. The result showed that the final water content of filtration cake in the crown of the maize was increased by -6.03% ~ 4.61% and 1.30%～8.15% in the root. At the same time, the yield of C1, C4 and C5 was decreased by 7.89%, 23.47% and 28.13%, respectively, while that of C2 and C3 was increased by 5.20% and 1.49%, respectively, water use efficiency was improved by 0.33%, 26.25%, 18.27%, 6.64% and 16.94%, respectively, and five treatments saved 8.26%,16.71%,14.07%,28.35% and 38.54% of water, respectively. The moderate treatment in seeding stage and the mild treatment in jointing stage were the appropriate water deficit treatments for maize under drip irrigation in water saving and production increasing. The result was of practical significance to guide the establishment of reasonable irrigation system for maize in western area of Heilongjiang Province.

Abstract:Field crop evapotranspiration (ETc) plays a key role in energy and water balance of agricultural systems， and the estimation of ETc under the sand-gravel mulching conditions is vital for assessing the influences of sand-gravel mulching on field crops. In order to accurately estimate the evapotranspiration of winter wheat under the conditions of sand-gravel mulching, the dynamic observation system of the lysimeter under a rain shelter was established in Yangling, Shaanxi. The FAO-56 Penman-Monteith equation was used to calculate the reference crop evapotranspiration (ETo). A weighing lysimeter was used to measure actual ETc of winter wheat under the different sand-gravel mulching amounts. The single and dual crop coefficient approaches were adopted in conjunction with ETo to estimate measured ETc. The results showed that a good linear relationship was obtained between single crop coefficient and sand-gravel mulching amounts at the three different growth stages of winter wheat. The equation can better simulate ETc of winter wheat under the sand-gravel mulching conditions. The ranges of determination coefficient (R2) between measured ETc and ETcS (ETc estimated by the single crop coefficient method) were 0.77~0.80 (in the first year) and 0.73~0.76 (in the second year), respectively. There was a good linear relationship between dual crop coefficient and sand-gravel mulching amounts. This relationship was introduced to modify the dual crop coefficient under sand-gravel mulching conditions. The modified dual crop coefficient approach can also better simulate ETc of winter wheat under different sand-gravel mulching amounts compared with the measured ETc. The ranges of R2 between the measured ETc and the simulated ETc were 0.83~0.88 (in the first year) and 0.87~0.92 (in the second year), respectively. The single crop coefficient approach simulated average evapotranspiration better than the dual crop coefficient approach, although the dual crop coefficient approach was more accurate on daily ETc. In conclusion, the single and dual crop coefficient approaches were still applicable for estimating the ETc of winter wheat under the sand-gravel mulching conditions, but it needed revision by using the measured data.

Abstract:In order to discuss the effects of nitrogen fertilizers application on the variability of paddy quality in black soil region, the example of black soil of typical cold area was taken and treated with 0, 60kg/hm2, 85kg/hm2, 110kg/hm2, 135kg/hm2 and 160kg/hm2 of nitrogen fertilizer under water saving irrigation condition. The field system sampling data for three main paddy quality indicators of protein, amylose and chalkiness in mature paddy were studied, the variability of three paddy quality indicators was investigated by using geostatistics theory, and a semi-variogram model was established. The results showed that the different nitrogen applications can not only promote paddy quality improvement, but also reduce paddy quality difference in the field area. Except that chalkiness and protein treated with no nitrogen fertilizer was the medium variation, all the other treatments were weak variation. In these three indicators, amylose was the most largest positive space correlation range, which was greater than the positive correlation of protein and chalkiness space. It was showed that the water and nitrogen management had the greatest influence on the variability of amylose in cold region. With the increase of nitrogen application rate, the nitrate nitrogen and ammonium nitrogen in soil were increased first and then decreased. The changes of nitrate and ammonium nitrogen contents in soils with different nitrogen application rates were in the opposite order to the spatial variation of paddy, which were in a descending trend as WS0, WS60, WS85, WS160, WS135 and WS110, it was showed that the different nitrogen contents had some influence on the variability of paddy quality, the results showed that the application of different nitrogen fertilizers could change the contents of nitrate and ammonium nitrogen in soil and then had a certain impact on the rice quality variability. The optimum nitrogen fertilizer application was 110kg/hm2, and the three paddy quality indexes and its growth matrix had good regional characteristics and spatial structure. The introduction of geostatistics not only compensated the deficiency of classical statistical analysis, but also provided theoretical basis for spatial structure and quantitative research of water-fertilizer-soil-crop system information.

Abstract:The topological structure of soil pores determined the ability of soil moisture retention and conductivity, which had a significant impact on soil ecological processes. However, the existing pore identification methods had the problems of low pore identification accuracy and low operational efficiency. In order to solve the problems, a fast fuzzy C-means (GFFCM) method based on the grayscale-gradient features of soil CT images for pore identification was proposed. The grayscale-gradient two-dimensional feature matrix was established by Laplace operator to describe the characteristics of pore boundary. Combined with soil prior knowledge, the initial membership matrix was constructed and the number of clusters was estimated. Then, based on the determined initial conditions, the traditional fuzzy C-means was used to realize the fuzzy division of soil structure. Finally, the fuzzy clustering result was optimized with the GFFCM method by pore identification standard to accurately identify the soil pore structure. The methods were applied to the soil CT images with unsaturated state and compared with the traditional FCM method and the fast FCM method (FFCM), the GFFCM method had the lowest identification error rate and the smallest number of iterations, which indicated that the GFFCM method had the highest recognition accuracy. Besides, the method could overcome the shortcomings of the traditional FCM method in initializing the membership matrix and number of clusters, so it solved the problem that the initial value influenced the identification accuracy and had the advantage of high computational efficiency.

Abstract:Freezing-thawing effect is the main inducement for the damage of channel in cold region, and the different forms of damage caused by it have seriously restricted the grain production. To explore the influence of freeze-thaw on physical and mechanical properties of saturated silty clay, after 0~11 cycles for saturated soil in the low temperature environment simulation test chamber, indoor geotechnical engineering test was applied, and grey correlation degree was used to analyze the interaction effect of soil properties and the following conclusions were drawn: with the increase of freeze-thaw cycle times, the cohesive force of saturated soil was decreased gradually with the form of single exponential function and the internal friction angle was increased gradually. The effect of freeze-thaw on cohesion was obviously attenuated after initial freezing and thawing. With the increase of freezing and thawing cycles, the damage coefficient Kφ was in a logarithmic function form change and the KC was in an exponential function form change. The coefficient of thermal conductivity and average dry density was negatively correlated with freeze-thaw cycle times, whereas the average porosity rate and permeability coefficient were positively correlated with freeze-thaw cycle times. Compared with the freeze-thaw action, the average porosity rate had a greater influence on the cohesion force, thermal conductivity, average dry density and permeability coefficient. For a single specimen, the influence of physical properties on the change of mechanical properties was in a descending order of average porosity, average dry density, permeability coefficient and thermal conductivity.

Abstract:As a kind of compositional data, the spatial interpolation of soil mechanical composition needs to meet four constraints of constant sum, nonnegativity, linear unbiased estimation and error minimization. Therefore, it usually needs to be transformed before spatial interpolation. A novel transformation method-spherical coordinate transform method was proposed and the study area was located in Yinbei Irrigation District, Ningxia Hui Autonomous Region. Firstly, the sampled soil mechanical composition data was transformed through three methods, including symmetry logratio transform method, asymmetry logratio transform method and the proposed spherical coordinate transform method, respectively. Then the soil mechanical composition spatial interpolation was realized with the application of ordinary Kriging. Secondly, the soil mechanical composition interpolation maps of different transform methods were compared to analyze the scientificity and feasibility of the proposed transform approach. The precision and fitting effect were assessed by utilizing the mean absolute error (MAE), root mean square error (RMSE), index of agreement (d) and Pearson’s correlation (R). The results indicated that spherical coordinate transform technology not only can satisfy the four constraint conditions but also had superior interpolation accuracy for sand and silt content than the other two logratio transform methods. However, the logratio transform methods had more accurate interpolation results than spherical coordinate transform method for clay content prediction. To summarize, a novel transform technology with the advantages of easy understanding, small calculation amount, and good interpolation precision and without consideration of zero values for spatial interpolation of soil mechanical composition was presented.

Abstract:Water and sediment movement in filter is complex and changeable. In the beginning, local blockage on filter element caused by non-uniform distribution of sediment affects flow distribution which will change tracks of follow-up sediment. Using CFD-DEM（computational fluid dynamics, CFD;discrete element method，DEM) method to simulate flow field and sediment distribution in Y-type screen filter, the resistance characteristics of filter and its influence on the movement and distribution of sediment were directly reflected. Results showed that the obvious backflow, vortex and viscous flow in the whole flow field led the uneven flow rate which was higher in outlet area and lower in inlet area, with a difference of 39%. Filter element was responsible for 90% of the total pressure loss. Flow condition was changed significantly with time, while sediment deposition appeared in the order of outlet under area, outlet upper area, inlet under area, inlet upper area and finally blocked the whole filter element. Among the four face areas in the filter element, sediment deposition was the least in outlet upper area which was at high flow rate while most in inlet upper area which was at low flow rate. So appropriately raising the flow section of outlet upper area with a better performance can improve the filtration efficiency.

Abstract:The use of anaerobic fermentation technology of agriculture wastes for the production of volatile fatty acids (VFAs) is a promising approach. The aim of this investigation was to evaluate the different pretreatments of rice straw like hydrothermal, acid and alkali on the AD process parameters and the VFAs production at mesophilic (35℃), thermophilic (55℃) and hyper-thermophilic (70℃). The results showed that the alkaline pretreatment was more favorable for VFAs production than acid and hydrothermal treatments. The lignin degradation rate with Ca(OH)2 at 35℃ was 63.27%, which was much higher than that of hydrothermal treatment group (12.45%) and that of HCl treatment group (12.40%). The pH value was in the range of 6±0.5 at alkali pretreatment. The efficiency of converting the degraded straw into VFAs at mesophilic was high, resulting in the highest VFAs yield. The VFAs yield with per degradation volatile solid in the pretreatment group was 0.79 ~ 1.20g/g and 0.24 ~ 0.51g/g at 35℃ and 70℃, respectively. The preferred alkali treatment group gave a yield of VFAs production of 0.25g/g at 35℃ and 0.09g/g at 70℃, respectively. The results can provide some theoretical basis to enhance the VFAs production from rice straw under different conditions.

Abstract:In recent years, with the growth of population and shortage of fossil energy, the environmental pollution problem has become more severe. Eucalyptus planted in south China is a kind of biomass resource with large quantity and high quality. The thermochemical conversion of biomass (pyrolysis, gasification, or combustion) is one of the most promising non-nuclear forms of future energy. It is a renewable source of energy and has many advantages from the ecological point of view. Pyrolysis of wood is a very complicated physical and chemical process which can transform biomass into useful fuel, such as bio-char, bio-oil and gas. Studying its thermo-physical properties is of great significance for the design of the equipment, control of process parameters and quality of the product. In the self-designed fixed bed pyrolysis device, the eucalyptus wood chips were paralyzed in the temperature range of 150~850℃. The remaining bio-char proceeds to be tested for the thermal parameters, including solid yield, bulk density, volume energy density, specific heat and heat conductivity coefficient. The results showed that with the increase of temperature, the solid yield was decreased and the weight loss rate in temperature range of 150~350℃ was up to 31.40% per 100℃;the lower heating value (LHV) of samples was increased gradually. The LHV of bio-char at 750℃ was 95.53% higher than that of the raw eucalyptus. Bulk density was decreased first and then increased while the volume energy density (VED) was increased in the whole experimental temperature range. The VED of bio-char at 750℃ was up to 63.21% more intensive than the raw material. The specific heat and heat conductivity coefficient were closely related to the moisture content and pores structure in bio-char. With the increase of treated temperature, the specific heat of sample presented a U-shaped tendency which was decreased firstly and then increased significantly. The heat conductivity coefficient was increased according to exponential growth after slight decrease. The fitting equations of specific heat Cp and heat conductivity coefficient λ with temperature were obtained and the fitting degrees R2 were 0.9320 and 0.9953, respectively.

Abstract:The enzymatic hydrolysis and biogas fermentation of anaerobically digested fiber from volatile fatty acids (VFAs) production with rice straw were studied. The effects of two-step pretreatment of acetic acid and aqueous ammonia on the degradation of lignocellulose, glucose concentration, xylose concentration and biogas production were explored. The results showed that two-step pretreatment of acetic acid and aqueous ammonia can further degrade the hemicellulose and lignin in anaerobically digested fiber from VFAs production, and the recovery rate of cellulose was higher, which was 77.47%~81.44%. Among them, the mass fraction of cellulose was 56.82% and the mass fraction of hemicellulose was only 7.94% for pretreatment of 4% acetic acid and 10% aqueous ammonia at 121℃. Under the above pretreatment conditions, the enzymatic saccharification efficiency was the highest, the mass concentration of glucose was 47.46g/L, and the glucose yield was 67.73%. Furthermore, the biogas production rate of anaerobically digested fiber from volatile fatty acids production pretreated by two-step pretreatment was better than those of acetic acid pretreatment alone and aqueous ammonia pretreatment alone. The highest biogas yield (414mL/g) was obtained. Two-step pretreatment effectively improved the biogas yield of anaerobically digested fiber from VFAs production. Therefore, the research proved a new biorefinery way of anaerobically digested fiber.

Abstract:In order to estimate numbers of single species freshwater fish, the passive acoustic signals of different quantities crucian carp and bream fish were used as samples. The acoustic signals of the freshwater fish were collected by the HTI-96-MIN standard hydrophone. The extracting schemes of sample characteristics were compared by using 4 ~ 6 layer wavelet packet decomposition algorithms. The short-time average zero-crossing rate and the frequency band energy calculated by 6 layer wavelet packet decomposition algorithm were determined as the signal characteristics of crucian carp. And the characteristics of bream fish were the frequency band energy calculated by 6 layer wavelet packet decomposition algorithm only. According to the research results of different sample sets dividing methods, the final sample sets dividing methods of crucian carp and bream fish were Rank-SPXY (m=10) and Rank-SPXY (m=5). Furthermore, the key characteristics of the samples were chosen by competitive adaptive reweighted sampling. Finally, some numbers estimate models of the freshwater fish were established with the multiple linear regression and partial least squares regression. The results indicated that the performance of the multiple linear regression model was better. The multiple correlation coefficients of the numbers estimate models of crucian carp and bream fish were 0.835 and 0.893, and the relative percent deviations were 1.79 and 2.01, respectively. The numbers estimate methods proposed had good performance. It provided a new means for monitoring the freshwater fish quantity.

Abstract:In order to realize the aim of controlling multiple microscreen drum filters with frame in recirculating aquaculture systems wastewater treatment processing, manage and maintain the system conveniently as well as save production costs, three kinds of operation modes control programs of ten microscreen drum filters were programmed with STEP 7 MicroWIN SP9 V4.0 software. The results of PLC real-time monitoring and debugging showed that the operation modes of the control system could be switched freely, and the microscreen drum filters could work normally in manual mode, automatic mode and timing mode. More concretely, taking one of the filters as an example, for manual mode, the backwashing can be controlled and stopped at any time;for automatic mode, the start and stop of the reducer and the backwashing pump were controlled by two level switches, when they were triggered by the water in the drum, the backwashing was performed, when the water level was dropped below the low level switch, backwashing would stop, and if the switches had malfunctions, backwashing would not proceed;for timing mode, the backwashing time and frequency can be set according to the water quality. In aquaculture environment, the use of multi-mode soft logic control system to make multiple microscreen drum filters’ reducers and backwashing pumps run and stop had the advantages of good stability, high degree of automation and low costs compared with the traditional hard logic control system which went wrong easily and was difficult to be overhauled, and the former can better cope with the problems of system failure. The research results can provide some references for the further improvements of control system of the microscreen drum filters and the automation integration of aquaculture equipments.

Abstract:Starch food is easy to retrograde during processing, transportation and storage, and the degree of retrogradation seriously affects the nutritional value and shelf-life of starch food. Soretrogradation degree is really expected to determine rapidly and non-destructively during storage, that is near-infrared and mid-infrared spectroscopy. The near-infrared and mid-infrared spectra of starch in different storage times (0d, 1d, 2d, 3d, 4d, 5d, 10d, 15d and 20d) were collected. There was a certain associations between spectra data and chemical reference detected by spectrophotometry, then chemometrics (partial least squares, PLS) were used to establish the prediction model of starch retrogradation with near-infrared, mid-infrared and fusion data, the best one that had higher correlation coefficient and lower error was chosen. The results showed that the backward interval partial least squares (biPLS) prediction model of fusion technology was the best one, the root mean square error of cross-validation (RMSECV) and root mean square error of prediction (RMSEP) were 6.79% and 9.52%, and the calibration and prediction correlation coefficient were 0.9655 and 0.9313, respectively. The results indicated that the fusion spectroscopy was superior to any single spectral technique, which could provide more accurately information of starch. Hence, the infrared spectroscopy could detect the retrogradation degree of corn starch rapidly and non-destructively, provide guidance for the processing of starchy food, and ensure the quality and safety of starchy food.

Abstract:In order to realize fast, nondestructive and real-time measurement of parameters (moisture) for pork on-line and divide pork into qualified and unqualified class according to GB/T 18394—2010 (pork moisture limit value ≤76.5%), an on-line detection and classification system was designed and developed based on near infrared reflectance spectra. To determine the detecting distance from the probe to the surface of the sample, optimizing platform was set up, which included spectrum acquisition unit, distance detection unit, light source unit, transmission unit and control unit. NIR spectra (349~1761nm) were obtained from 54 samples with different detecting distances in the range of 5~29mm at approximately 2mm intervals under static conditions. Moisture contents were determined by traditional methods and then related with the spectral information by partial least-squares (PLS) regression models with the first band (349~1435nm), the second band (1037~1761nm) and double-band. The result showed that a detecting distance of 19mm was the best to model. Based on optimal distance, spectra were obtained from 45 samples at static state and on-line by adjusting system of detection distance and multi points simultaneous detection, and then two PLS models were established. The optimal correlation coefficients of the model were 0.915 and 0.906, respectively. The two models results were almost the same. It verified the feasibility of predicting pork moisture on-line. In order to verify stability and precision of models for detecting online, NIR spectra were obtained from another 21 samples. The results showed that the NIR spectral range had an excellent ability to predict the content of moisture (R2=0.8367) in pork online and classification accuracy was 90.48%. Results indicated that NIR spectroscopy was a promising technique to roughly predict moisture of intact fresh pork on-line.

Abstract:With the aim to investigate apoptosis-inducing-factor (AIF)-mediate apoptosis and mechanism of lysosomal cathepsins involved in AIF activation of bovine muscle during postmortem aging, six healthy Simmental crossbreeding local yellow cattle were slaughtered and longissimus thoracic muscles were removed from the carcasses then aged at 4℃ for 6h, 12h, 24h, 72h, 120h and 168h. At the end of each storage period, ROS content, lysosomal membrane stability, cathepsins activities, mitochondrial membrane permeability, the expression of AIF and nuclear morphology were measured. The results suggested that ROS content was decreased from 0h to 6h, but it was significantly increased from 6h to 168h during postmortem aging (P<0.05). Lysosomal membrane stability was significantly decreased from 0h to 168h (P<0.05). Cathepsin B, D and L activities were increased as the postmortem aging was increased (P<0.05). Mitochondrial membrane permeability was significantly increased during postmortem aging (P<0.05). The AIF level in mitochondria was significantly increased from 0h to 12h and decreased as the postmortem aging was increased, the amount of AIF in the nucleus was increased during postmortem aging (P<0.05). The volume of cell nucleus was gradually increased and some nucleus were dissolved and broken during bovine postmortem aging. It was concluded that the generation of ROS may lead to imbalance of lysosomal membrane stability, and then cathepsins were released to cytoplasm. Subsequently, the mitochondrial outer membrane was permeabilized, and AIF was translocated to the cytosol and nucleus, where it induced apoptosis of nucleus.

Abstract:Peanuts are rich in protein and lipids, which are widely cultivated in the north and south regions of China. As one of the main oil crops in China, the identification of peanut varieties is very important for breeding new varieties, improving oil production and processing quality. The commonly used detection methods such as experience identification, physical and chemical detection are all time-consuming and difficult to operate, could not meet the current rapid detection requirements well. So it is necessary to explore a rapid and efficient testing method for peanut varieties’ identification. Terahertz attenuated total reflection (THz-ATR) spectroscopy combined with distance matching algorithm (DM) were used to achieve the rapid identification of different varieties of peanut. A total of 60 peanut samples’ ATR spectrum in 0.3~3.6THz which included three varieties of peanuts: Huayu 36, Luhua 1 and Luhua 9 were collected randomly. Then the first derivative of ATR absorption coefficients were normalized to establish DM model and identify different peanut varieties rapidly. The final DM model result showed that the overall recognition accuracy of the three categories can reach 93.3%, with only one sample was misclassified. The research results showed that using THz-ATR to rapid detection and identification of peanut varieties had certain feasibility, and the method can be applied to other crop variety rapid identification and quality analysis because of its simpleoperation and efficient characteristics.

Abstract:Cynanchum otophyllum Schneid. contains the coagulant protease. The leaves of Cynanchum otophyllum are widely used to produce the milk cake (a traditional cheese) by the minority ethnic region in Yunnan Province. Milk cake made by Cynanchum otophyllum leaves usually forms a soft curd. The object was to extract the active coagulant components based on the leaves of Cynanchum otophyllum and apply the extract into milk cake manufacture. The results showed that the optimal extraction temperature to produce Cynanchum otophyllum coagulant was 4℃, while the optimal extraction liquid-solid ratio was 20mL/g and the optimal extraction solution was the citric acid-phosphate buffer (containing 150mmol/L NaCl, 1mmol/L Cys and EDTA). Compared with the milk cake made by the soaking solution of Cynanchum otophyllum leaves, the yield, protein and fat recovery rate of milk cake made by the extracted coagulant were significantly improved, with the recovery rate for protein and fat of 20.26 and 33.04 percentage points, respectively. Moreover, the milk cake made by extracted coagulant showed a more suitable hardness, higher degree of adhesion and more uniform gel network structure compared with the milk cake made by soaking solution. The study provided a reference for the development of Cynanchum otophyllum coagulant and promoted the industrialization of Yunnan traditional milk cake products.

Abstract:The concentration of bioactive components was the key factor to functionality of fermented food. The object was to develop and characterize a sprouted soybeans- based fermented milk by using γ-amino butyric acid (GABA)-producing Lactobacillus plantarum S-35. Inoculation volume, fermentation time and fermentation temperature were studied as single factors affecting the yields of GABA in the fermented milk. The central composite design was used to optimize the fermentation technology. The results were analyzed with the software Design-Expert 8.0.6. Results indicated that the fermentation system model had an extremely significant effect on predicting the results of the test. Results of the response surface optimization test showed that the optimal fermentation condition was as follows: inoculation volume was 3.5%, fermentation time was 27h, and fermentation temperature was 34.5℃. The verification tests demonstrated that the actual yields of GABA was 1.61g/L, and the maximum number of viable probiotics count was 1.60×109CFU/mL. When it was stored at 4℃ after 7d, the product had good quality with sensory evaluation, viable cell numbers and pH value. The research results proposed specific processes and fermentation conditions for GABA enrichment in sprouted soybeans, which can provide a new, natural, and functional food resource.

Abstract:The existing intelligent vehicle trajectory tracking controller have the problems such as low tracking accuracy and weak robustness. In order to solve these problems and improve track tracking effect, a sliding mode control method based on a new reaching law was proposed because the sliding mode control had the advantages of quick response and strong anti-interference ability. The new reaching law was the combination of a special function and a inverse hyperbolic sine, which made sure that the system state can approach the sliding surface quickly whether it was near the sliding surface or not. The law really avoided the shortcoming of the traditional algorithms and improved the approaching speed of the controlled system and limited the vibration. The controller that used this method can control the vehicle to track the reference trajectory quickly. In order to prove the effectiveness of this method, a vehicle kinematics model was built and the trajectory simulation experiment was carried out in Simulink to compare the control effect of the new reaching law with the double power reaching law. The results of the simulation verified that the new reaching law had higher approaching speed and weaker vibration and it had better control effect. Controlled by the sliding mode control method based on the new reaching law, the convergence speed of horizontal and vertical errors of the vehicle kinematics model was significantly increased, the vibration of course angle error became weak, and the vehicle kinematics model can track the trajectory faster.

Abstract:Diesel oxidation catalyst outlet temperature control is crucial for heat management to realize diesel particulate filter active regenerative control. Combined with the actual characteristics of DOC to analyze and research the heat transfer process and chemical reaction characteristics in DOC, a first-order plus delay response model was established for the DOC carrier outlet temperature control. And the model was verified by the carrier test data on the engine bench. The relationships were described by a linear equation between the exhaust flow and thermal response time constant and a hyperbola equation with exhaust flow rate and delay time constant. According to the system characteristics, a PID control strategy was developed based on the internal model control structure, and the delay part of the system response used two order Pade non symmetry approximation method to substitute. Based on the internal model control structure, a filter was proposed to establish. The filter can regulate the response time and system stability. And by turning the parameter of filter, it can calculate the parameters of PID. The proposed control strategy was tested by engine test bench. To test a dynamic control effects, a continuous variety working condition with significantly changes in the exhaust flow and the entrance temperature of DOC for testing, the outlet temperature can be controlled within ±20℃ at the target temperature of 575℃. The test results proved that the strategy was effective to control the temperature of oxidation catalyst outlet, and the strategy can provide a rational thermal management for DPF active regeneration.

Abstract:In view of faults of the current 3D printing technology such as the long processing time and low production efficiency, a path optimization algorithm of 3D printing based on fused deposition modeling was developed. Because the slice contour of some printing parts was comprised of many closed curves, the starting point of each closed curve was determined by the nearest neighbor method and the 3D printing contour path planning was transformed into the trareling salesman problem. A contour path planning algorithm based on ant colony algorithm was developed in order to plan printing sequence of the contour paths reasonably. Parallel scanning method was adopted for filling the slice cross-section. Influence on printing efficiency and quality for different scanning angles was analyzed and optimal scanning angle was selected. The scanning area was divided into different areas and a region merging algorithm based on four-point method was developed. The printing sequence of the different areas was optimized by the nearest neighbor algorithm, which improved the scanning efficiency and molding quality. The experiment of printing parts was done by means of the path optimization algorithm. Compared with the traditional parallel scanning method, single layer contour path scanning lengths of the three parts were decreased by 19.5%, 12.5% and 10.7%，the printing time was decreased by 12.6%, 11.6% and 8.9% and the dimensional accuracy and surface quality were improved. The result showed that the path optimization algorithm was robust and effective and its efficiency was high.

Abstract:To realize 3D CAD model reuse requirement of multi-granularity, precise and intelligent in design field more efficiently, a method of typical structure mining in 3D CAD model and similarity evaluation based on simulated annealing algorithm was proposed. Firstly, attribute adjacent graph of CAD model was established through extracting topological and geometrical information from the 3D CAD model represented by B-rep, which can record face and edge detailed structures of 3D CAD model and its organization and association. Then, according to its description carrier, association graph and association graph matrix were established with the mapping relation of vertex and edge in attribute adjacency graph between typical structure and CAD model, and a mechanism of similarity estimation was proposed at the same time. At last, typical structure mining in 3D CAD model was accomplished based on simulated annealing algorithm through excavating maximal clique in association graph, while similarity estimation between typical structure and return model was accomplished. Using general model base, agricultural machine and equipment model base, algorithms testing and validating were completed compared with ant colony algorithm and genetic algorithm. Experimental results showed that the proposed method can realize typical structure mining in 3D CAD model and similarity estimation, which can effectively support design reuse of feature or local structure in 3D CAD models design domain.

Abstract:Large-scale heavy-burden parallel stabilizing cargo-receiving platform (PSCRP) plays an important role in the safe transporting of container cargo on the sea. According to the engineering needs, a PSCRP with three morph scissors mechanism (MSM) limbs was innovatively designed. The MSM limb, with the function of displacement amplification, contained a subclosed loop kinematic chain URRRU (U (U denoted universal joint and R denoted revolute joint) and two SPS (S denoted spherical joint and P denoted prismatic pair) drive units. The MSM limb was equivalent with RPS kinematic chain when the two SPS drive units of the MSM limb were synchronously driven. In the non-inertial system, the parasitic displacement, velocity and acceleration of the upper-platform of the PSCRP were firstly analyzed based on vector method, and the position solution of the PSCRP mechanism was correspondingly obtained. Then the kinematics and dynamics analytic modellings of the PSCRP mechanism were established based on screw theory. Finally, the correctness of the models was verified by numerical example. A theoretical foundation was laid for the follow-up structural optimization and control of the PSCRP mechanism.

Abstract:Based on ostrich foot locomotion posture, energy storage and vibration reduction mechanism of the metatarsophalangeal joint (MTP), a bionic adaptive low vibration walking wheel was designed to improve the low vibration performance. Through the finite element method (FEM), motion process of the walking wheel was analyzed on the soft/hard ground. The result showed that under the condition of 30N load and 10(°)/s, the fluctuation range of the bionic walking wheel center was reduced by 85.71% and 93.33% on the soft and hard ground, respectively. In order to further verify the vibration reduction performance of the bionic walking wheel, the light load of lunar soil/wheel interaction test system was employed for test. When the slip ratio was smaller than 40%, the drawbar pulling force of the bionic walking wheel was all larger than the traditional walking wheel. When the slip ratio was larger than 40% and the speed was 20(°)/s, the drawbar pulling force of the bionic walking wheel was less than the traditional walking wheel. The results showed that the bionic walking wheel was provided with better traction and passing-through performances on the soft ground. Under the condition of 30(°)/s, the accelerations were reduced by 6.3% and 15.8% on the soft and hard ground, respectively. Meanwhile, the amplitudes were reduced by 14.6% and 9.6%, respectively. On the premise that passingthrough performances of the bionic wheel was assured, combining the simulation and test data on the soft and hard ground, the wheel center fluctuation of the bionic walking wheel was smaller than that of the traditional walking wheel. Therefore, the vibration of the walking wheel, caused by polygon effect, was solved effectively.