Abstract:The foundation and guarantee role of the modern agriculture mechanical properties of soil-engaging components was analyzed and the primary performance parameters of soil-engaging components that need optimization at present was also summarized, which mainly included drag reduction and consumption reduction, anti-adhesion and desorption, wear resistance and life extensional and the satisfying requirements of agronomy. The main research methods to optimize the structure and properties of soil-engaging components were summarized, which mainly included clearing the interaction between soil and soil-engaging components, optimizing material composition and machining process technology, aiming at the structure function design of agronomy. And the developing orientation of agricultural machinery soil-engaging components in China was prospected, which mainly included strengthening the basic theory research, overcoming the high-performance material processing bottleneck, designing soil-engaging components by using comprehensive and advanced approach.

Abstract:With the improvement of the farm mechanization level, more ‘corporate’ style farming emerged. For example, more than one harvester collaborated with each other to complete the task of harvesting operations. The new ‘corporate’ style farming created several new challenges for the agricultural machinery navigation, and the group navigation was the trend of the development of agricultural machinery navigation technology. Group collaborative navigation control is the critical technical problem to be resolved. In order to solve this problem, a collaborative navigation control method based on the leader-follower structure was proposed. Firstly, the harvester group based on master-slave structure was introduced, and a kinematics model of harvester group was established on the basis of kinematics analysis. Secondly, a formation keeping control law and a path following control law were designed on the basis of feedback linearization and sliding mode control theory. Finally, in order to verify the effectiveness of the proposed model and method, the formation experiments were carried out. When the leader and follower ran at speed of 1.0m/s, the average error of the leader and follower were respectively 5.81cm and 5.93cm. The experimental results showed that the average navigation errors of the harvester group were similar to the average navigation error of a single farm machinery, and the proposed method could meet the harvester navigation demand.

Abstract:Because of the existing problems in path planning of greenhouse robot under complex environment, a directional A* algorithm was proposed. This method was focused on the smooth design, collision detection and the algorithm efficiency. Firstly, the “line of sight” solutions were used to smooth the path for getting rid of the zigzag effect and collisions. Secondly, the “arc-line-arc” turning methods were applied to avoid the width of the greenhouse robot in path finding. At last, some basic optimizations based on the binary heap were carried out to speed up the directional A* algorithm. Simulation and comparison results between the improved A* algorithm and traditional one showed that the proposed method was more efficient. It can not only meet the requirements of smooth, but also predict collision after proceeding with turning strategy. At the same time, the accelerating algorithm based on the binary heap made the path finding 4~7 times faster. Moreover, a path planning and tracking test was carried out in laboratory environment, where a simulation greenhouse was built. The results verified that the tracking precision can keep in a small range and the greenhouse robot can run without collision when the navigation path was given by the proposed algorithm, which proved the effectiveness and feasibility of the directional A* algorithm.

Abstract:Due to the limited battery power and pesticide capacity, the plant protection UAV need return to the supply point frequently in the process of plant protection. With the work area increasing, more time would be spent on battery replacement, pesticide filling and round trips between each return point and the supply point. So an appropriate path with the optimal return points must be planned before starting the work, in order to minimize the total time and improve the efficiency of the plant protection. For the purpose, a research was conducted on the path planning method for the plant protection UAV. Firstly, aiming at building an environment model which could describe the working area, the grid method was selected to divide the working area into small grids with the initialized weights, which were depended on the working area’s size and shape. Secondly, the UAV was made to fly from the current grid to the adjacent one with the highest probability, which was calculated according to both the grids’ initialized weights and the heading direction of the UAV. Incentive coefficients were added to the weights of the grids located in the front, left rear and right rear of the UAV so that the parallel routes were followed which moved from one extreme of the working area to the other alternately and turned at the boundary. Then the quantity and position of the return point could be outputted by controlling the distance in the spraying mode. Thirdly, a mathematical model was established. The quantities of the return times in the artificial planned path and the unplanned path were taken as the upper and lower limits of the search space respectively. The distance of each flight in the spraying mode was chosen as the variable, and the dimensions of which were depended on the search space. The objective was to obtain the optimal return points with the minimum time in the non-praying mode. After that the gravitational search algorithm (GSA) was applied to solve the model. Based on the methods and processes above, a new path planning method was proposed. Then the method would output the planned path with return points automatically by inputting the data about the environment and the UAV such as the size of the working area, the direction of the crop row and the speed of the UAV. At last, for the test of the performance of the proposed path planning method, a 700m×100m working area with the irregular boundary was taken as an example for the path calculation. The path calculated by the proposed method was also compared with the artificial planned path and the unplanned path respectively, which showed the non-praying distance of the proposed method was reduced by 14% and 68%, while the non-praying time was reduced by 21% and 36%. Furthermore, a field experiment with the real UAV was used to test the proposed deviation rectification algorithm. Finally, the study indicated that the proposed method which could produce paths with less working time was a reasonable, feasible and useful solution for the path planning problem of the plant protection UAV.

Abstract:In the aquatic plants cleaning process of crab culture, in order to reduce labor intensity of the farmers and improve the positioning accuracy of navigation, a kind of DGPS and vision integrated navigation positioning method was designed with immune particle swarm optimization (IPSO) to optimize the trace of Kalman filter, which combined the advantages of DGPS and visual navigation, and was applied to aquatic plants cleaning workboat. Firstly, the integrated navigation model was established, and then the state equation and observation equation of the system were obtained. In order to solve the divergence problem of UKF filtering for navigation model, PSO was used to obtain new particles, and immune algorithm was introduced to avoid premature phenomenon of PSO. Combining with UKF, the navigation model was filtered, and the new position coordinates were obtained. At last, the comparative experiment was conducted by simulation and navigation experiment. Simulation experiment results showed that the root mean square error (RMSE) at east and north positions of the proposed method were reduced by 46.09% and 71.51% compared with DGPS navigation, and reduced by 23.92% and 58.26% compared with integrated navigation, respectively. Navigation experiment results showed that in the same longitude position the latitude error of proposed method was reduced by 22.69% and 9.14% compared with DGPS and integrated navigation, respectively. The results showed that the navigation time of the proposed method was reduced by 4.77% and 4.32% compared with DGPS and integrated navigation, respectively.

Abstract:Lodging resistance of wheat is closely related to its stem section microstructure. Observation and analysis of stem microstructure are of great significance for the genetic breeding. A microscopic image measurement system was studied, which could be utilized to measure the main parameters of the wheat stem section accurately. The equipment including computer platform, image acquisition box and electronic microscopy imaging system etc. was used to build the hardware platform and the algorithm software was developed. According to the characteristics of the stem structure and color, the contours of both mechanical tissue and medullary cavity were obtained using image processing procedures. After then the geometrical parameters of the whole section, medullary cavity and sclerenchyma were calculated by the ellipses fitting. Based on the uniformity of the vascular bundle structure, an original template matching method was proposed. This method was invariant to scaling, translation and rotation, which was used to identify and count the vascular bundle in the target image. It showed that this automated measurement system was of high throughput and high precision. The system will play an important role in both the screening of important crops resources and population genetic research.

Abstract:Tea is a high-value crop throughout the world. Most fresh tea leaves are picked by machines, then various grades are mixed together including broken leaves and leaf stalks. In order to improve quality, the fresh tea leaves picked by machines need to be further classified. However, traditional methods such as winnowing and screening can only sort tea leaves roughly. A new kind of intelligent fresh-tea-leaf sorting system was proposed based on computer vision technology and deep learning method, which can identify and sort tea leaves automatically and accurately. In this system, convolution neural network (CNN) was used to recognize the images of fresh tea leaves, and there was a seven-layer network structure in the CNN identification model. Through image segmentation and scale transformation, the original image was normalized as the input of CNN. CNN was able to learn the characteristics of images independently and can avoid many complicated feature extraction. The preprocessed images were rotated and mapped to serve as the training set, which enhanced the generalization ability of CNN identification model. Meanwhile, the training performance was greatly improved by sharing weights and using a declining learning rate. Experiment results showed that the system can effectively sort out several kinds of tea leaves, single bud, a bud with a leaf, a bud with two leaves, a bud with three leaves, single leaf and leaf stalk. The identification accuracy was more than 90%.

Abstract:In order to improve the mechanization level of corn sorting, a kind of mechanical device with high efficiency and batch transportation of maize grain was designed to solve the problem that traditional corn sorting machine of grain was difficult to realize the batch transportation. The main structure, working principle and related structure parameters of the batch transportation device were described. Structural design of key components of the device, analysis of performance characteristics of amplitude difference type electromagnetic vibration system and batch transportation track were introduced. EDEM virtual simulation test was done on the device performance of the batch transportation, track arc central angle, wedge baffle angle and track width were taken as experiment factors, and batch column performance indicators were selected as test index of the virtual orthogonal experiment. The influence of related factors on the performance of the batch transportation was analyzed, and reasonable parameter combination was obtained as: the track width of 15.4mm, track arc central angle of 45° and wedge baffle angle of 110°. The bench test was carried out, the bench test results showed that the electromagnetic vibration amplitude was 1.5mm, frequency was 52Hz, the vibration direction angle was 28°, the installation angle was 0°, the added mass was 0.3kg, one side of plate spring was adjusted to 87°, the other side of plate spring was adjusted to 35°, the amplitude of the track with added mass was 1mm, the batch transportation qualified index was 83.1%, adhesion and retention index was 10.4%, hysteresis index was 6.5%. The batch transportation performance was good, which met the performance requirements of corn seed separator, and the research provided a theoretical and technical reference for the research and design of corn sorting device.

Abstract:An adaptive miss-seeding reseed device of no-tillage planter was developed to solve miss-seeding problems when working, and the mathematical model of the reseed device driver was established to implement the simulation analysis on the dynamic response performance of the compensation system device. Through the reseeding control algorithm, the distance (S) of reseeding device to main seed-metering device and the height (H) of seed-metering device to ground were determined and the relationship curves among reseed-metering plate speed (n), the seeding machine moving speed (vm) and the seed distance(Ll) were achieved, which further achieved the self-adaption performance of the reseeding machine. The bench test results on reseeding detection accuracy showed that the miss-seeding detection accuracy was 93.23%, the rate of reseeding of the system was 95.11%, the actual reseeding rate of reseeding was 91.95%, the detection error rate was 3.16%, the reseeding success rate of the system was 96.38%, the actual reseeding success rate was 89.89%, and the detection error rate was 6.49%. The tests of quadratic orthogonal regression on the height (H) of seed-metering device to ground, the seed distance (Ll) and the seeding machine moving speed (vm) showed that the performance of the reseeding device was the best with the height (H) of seed-metering device to ground of 15.33cm, the seed distance (Ll) of 25.16cm and the seeding machine moving speed (vm) of 3.52km/h, and the reseeding success rate was 96.5%. The field test results on reseeding performance showed that the average seeding qualification rate was 98.72%, which had an increase of 4.56% at speed of 3km/h to 6km/h. The research effectively improved the seeding quality and also provided reference for further study on seeding performance improvement of no-tillage planter as well as the promotion of agriculture mechanization level with information technology.

Abstract:In order to improve the filling performance of seed metering device with roller of air-suction, the numerical simulation on the height of seeds layer, the vibration frequency and the angle of vibration were carried out with method of discrete element analysis. The results showed that the arc length in the area of filling seeds and the time of filling seeds can be increased through increasing the height of seeds layer. The leakage rate can also be reduced under the same conditions; the mean value of normal stress was increased with the increase of vibration frequency, which meant that the disturbance to the seeds can be enhanced; the proper vibration angle can increase the height of filling seeds effectively. The filling performance of the seeds metering device can be improved effectively by reducing the internal friction force, enhancing the disturbance of the populations and increasing the height of filling seeds. Maize seeds (Zhengdan 958) were taken as research materials in order to determine the optimal combination of parameters. The seeding performance of metering device was studied through the quadratic rotation-orthogonal combination experiment. The height of seeds layer, the vibration frequency and the vibration angle were taken as main factors. The qualified rate, leak seeding rate and the re-seeding rate were taken as indexes. The mathematical model between three factors and the indexes was built. The effect of each factor on the qualified rate was analyzed and optimized parameters were tested. The effect of factors on the qualified seeding rate in primary sequence was the negative pressure, forward speed and angle of seeds suction. The optimal parameters were obtained. The qualified rate was above 90%, the leak seeding rate was lower than 5% and the re-seeding rate was also lower than 5%, when the vibration angle was 45°, the vibration frequency was 116~122Hz and the height of seeds layer was 96~117mm. The results of the verified experiment were consistent with optimal results. Conclusions can be drawn that the seed metering device with roller of air-suction had good adaptability to maize seeds. References for the design of the maize seeds metering device with roller of air-suction can be provided.

Abstract:In Huang-Huai-Hai area, the large amount of maize straw cover resulted in increasing difficulties in winter wheat sowing, and an integrated machine was developed to pick up, crush and bury the corn straw at single operation to cope with this problem. The trace and phase position of the guideway centerline of spring-finger cylinder pickup device were determined based on the working principle and working process analysis of the typical spring-finger cylinder pickup device. A kinematic analysis on spring-finger was carried out under practical condition, and changes in both movement trajectory and speed were able to meet the requirements. Straw was chopped with a fixed knife and a high-speed rotating knife, while the high-speed air flow within the crushing chamber that formed by the rotation of the chopping roller, as well as the baffle plates placed in the back of the crushing chamber, were used to adjust the proportion of the straw to be buried and scatter the partial straw from the places without baffle plates to the surface of ground. Ditching device, the outlet of straw guided-conveying device and the disc covering device were arranged from front to back, so as to sequentially complete ditching, straw-disposing and soil-covering. As indicated in the field experiment, the straw picking up rate was 93.5%, the qualification rate of straw chopping length was 92.6%, the trench depth stability ratio was 95.0% when at a operation speed of 3km/h, the proportion of straw that had been buried into the ditch was in accordance with the pre-set proportion, which showed that the proportion of the buried straw can be adjusted successfully through different widths of the baffle plates. As a consequence, all the technical indicators of this machine succeeded in meeting the technical requirements.

Abstract:As one of the most widely applied technology at present, near-earth spectrum detection technology has been used in precise variable fertilizer applicator for rice and wheat. In order to improve fertilizing performance stability and control precision of variable rate fertilizer applicator, the discrete element simulation model of outer groove-wheel variable applicator was established. To achieve the optimal structure of outer groove-wheel fertilizer apparatus, the discrete element method (DEM) and EDEM 2.2 software were put into use to analyze and numerically simulate the fertilizing performance. The effect of different fertilizer apparatus structures and control strategies for fertilizing on the stability of variable fertilization was studied, and with bench test and field trial to verify the accuracy of simulation model. The results showed that the fertilization variability of improved apparatus was significantly decreased, and the standard deviation was decreased by 14.59g, the variation coefficient was reduced by 9.9%. When the control strategy of speed priority was adopted, as the groove-opening was 19.34mm, it had the optimum fertilizer stability of 1.09%. When the control strategy of groove-opening priority was adopted, as the rotary speed of groove-wheel was 55.75r/min, the minimal fertilizer variability was 1.85%. And compared with the verification test results, the errors were less than 8.87%, 9.52% and 5.50%, respectively, verifying the accuracy of simulation and analysis for particle movement process in agricultural equipment using the DEM. The study illustrated that the improved fertilizer apparatus could perfect the stability of fertilizer and satisfy the demands of precision variable fertilization.

Abstract:In order to solve the problem that corn thresher can not automatically adjust the threshing clearance and reduce the mechanical damage in the process of corn threshing, the floating corn single panicle threshing device was designed. The threshing device was mainly composed of clearance adjustment device, feeding hopper, discrete roller, threshing roller, differential roller, etc. The clearance adjustment device could float and automatically adjust threshing clearance. It can adapt to the differences in the diameters of corn ears, which was conducive to reduce broken rate and increase threshing rate. When the water content of grain was below 25% and the speed of discrete roller and threshing roller was not more than 800r/min, the threshing device did not result in the fracture of corn cob. The feeding hopper realized the function of automatic separation of corn ears and discharge one by one. The optimum tilt angle of feeding hopper was 40° and the feeding height of corn ear was 132cm. Three parameters, including discrete roller speed, threshing roller speed and differential roller speed were selected as the input variables, and broken rate and un-threshing rate of corn grain were used as the test indexes. Parameter optimization experiment was completed on the floating corn single panicle threshing device by the method of quadratic regression orthogonal rotary combination. The optimization results showed that the discrete roller speed was 234r/min, the threshing roller speed was 511r/min and the differential roller speed was 91r/min. The actual grain broken rate was 0.25%, the actual un-threshing rate was 0.76% and the integrity rate of corn cob was 100% under the optimal parameter combination.

Abstract:In order to meet the requirement of the grass braid mechanization technology in the pasturing area such as the Qingzang Plateau, a grass braid forming device was designed with the function of twisting and plying referring to the principle of Siro-spinning. The mechanical analysis showed that grass braid forming process was affected by axial movement speed, rotating speed of twisting roller, radius of twisting roller and feed quantity. The final twist and twist angle of grass braid were only relevant to the rotational speed of twisting roller and the linear velocity of pulling rollers, but had nothing to do with the spinning time and length of twisting zone. As a new method, the maximum tension force that grass braid could bear was taken as assessment index of grass braid strength. The prototype experiment was carried out with oat straw with the moisture content of 61.05%. It showed that the productivity of the forming device was 427kg/h, the working power was 0.428kW, and the bulk density of formed grass braid was 143.3kg/m3,respectively, which met the design requirements of grass braid forming device. The results of tension tests showed that the maximum tension force of the grass braid was positively correlated with the twist angle, and the maximum force reached 300~350N when the displacement was equal to half of the length of grass. The fracture of grass braid was due to the slip between two bunches of grass, which had nothing to do with grass fracture. This method and experiment provided theoretical support for grass braid forming technology.

Abstract:In order to collect tobacco flowers cut off, an intelligent tobacco topping machine with clamping belt was designed. It was mainly composed of a high ground clearance chassis, an intelligent topping device with clamping belt and a collecting device. The high ground clearance chassis used four-wheel drive and steering technology, and it had advantages of good through performance and high stability. The intelligent topping device was made up of an image recognition and control system of tobacco height, a lifting mechanism, a belt clamping mechanism, a cutting mechanism, a blade disinfection system and a restrain-germinating spraying system. Tobacco height recognition, topping height adjustment, tobacco flower gathering, clamping and cutting, blade disinfection, restrain-germinating spraying and other joint operations can be achieved by this intelligent topping device. This device had advantages of compact structure, full function and high intelligence. Belt conveyor was installed below the bottom of topping device, and tobacco flowers cut off was transported to the collection basket. In order to reduce the drive torque of electric lifting motor, a counterweight was used to balance the topping mechanism, and 64% energy can be saved. Experimental results indicated that topping accuracy rate was about 95%, collecting accuracy rate was about 98%, and it can meet the production requirements.

Abstract:In order to study the rotating stall characteristics of axial-flow pump, the unsteady internal flow field in a large axial-flow pump was numerically simulated. The Pro/E software was used to build the pump model, which mainly consisted of inlet pipe, impeller, guide vane and outlet pipe. The unsteady flow was numerically simulated based on RANS solver and SST k-ω turbulence model. The real pump pressure pulsation was tested by high frequency dynamic pressure sensor. The streamlines and pressure pulsation in pump at different flow rates were explored. The experimental pressure pulsation results and the numerical results were close to each other, which illuminated the reliability of the numerical calculation method. The results showed that there were two reversed flow field areas in the leading edge closely to shroud and trailing edge closely to hub of blade suction surface under rotating stall condition. The dominant frequency under designed condition in the impeller inlet and the middle of guide vane was blade passing frequency. The dominant frequency under designed condition in the impeller outlet was guide passing frequency because of rotor-stator interaction. The pressure pulsation coefficient amplitude was markedly increased under deep rotating stall condition. The pressure pulsation coefficient amplitude of monitoring point G6 at guide vane outlet under deep rotating stall condition was 16 times larger than that under designed condition. Low frequency pressure pulsation at 0.83Hz disappeared under deep rotating stall condition which was caused by a vortex in guide vane. The research had reference value for the safe and steady operation of pump unit in large pumping station.

Abstract:Due to the factors such as sensor spatial resolution and heterogeneity of surface features, the mixed-pixels were commonly found in medium-spatial resolution remote sensing data, especially in hilly areas, strong topographic relief, diversity, breakage, mixed distribution and scattered layout of the surface features and other factors constituted the difficulties of remote-sensing image classification mapping. In order to improve the classification accuracy for land use in hilly areas and provide data support for land use monitoring, a combined approach of multiple endmember spectral mixture analysis (MESMA) and random forest (RF) was explored. Based on data source of Landsat-8 operational land imager (OLI) sensor data, the fractional abundance of vegetation, impervious surface and soil was firstly extracted through MESMA. Secondly, totally 20 feature variables were figured out and three combined models were constructed on the basis of data image spectrum, texture and fraction variables to carry out random forest classification experiment. Through comparing between the optimal result from the experiment and SVM and MLC classification results, including the same number of variables, the results indicated that MESMA can derive accurate fraction information. The inclusion of fraction information could help to improve the mapping accuracy of all classification methods (RF, SVM and MLC), which can be up to 90.50%, 88.85% and 86.35%, respectively, the gain of RF classification accuracy was most significant. Comparing with LSMA, the fraction variable generated by MESMA was more useful for improving the accuracy. The combined method of MESMA and RF can achieve the comparatively accurate classification map in the multi-feature variables. The accuracy was better than those of SVM and MLC classification results with the same feature variables. Therefore, the proposed method can obtain high precision in land use classification in hilly area. Based on this method, remote sensing image interpretation of large scales can provide technical support and rational reference for land reclamation monitoring.

Abstract:As an important part of terrestrial ecosystem, forest is concerned by its huge carbon storage and carbon sequestration capacity. With the successful launch of China’s high score 1 (GF-1) satellite, it is possible to use NDVI data to realize the quantitative extraction of forest cover. However, due to the impact of rainy weather, operating costs and other factors, it is difficult to form NDVI GF-1 time series data, which cannot meet the demand for high precision extraction of forest cover. With the aim to solve this problem, Songshan was taken as part of the Henan GF-1/WFV NDVI and MODIS NDVI experimentation area, application of STAVFM algorithm was integrated, and GF-1/WFV NDVI time series data was used to generate the 8 d step, then from the time series data in NDVI feature extraction and spectral features were combined with GF-1/WFV. Finally, SVM classification method was used to realize quantitative forest coverage extraction. The research results showed that the NDVI GF-1/WFV sequence data generated by the STAVFM algorithm was ideal, which can solve the problem of the NDVI GF-1 time series data. The overall classification accuracy based on the SVM classification was 94.72%, which was improved by 4.90 percentage points compared with the classification results of the original GF-1/WFV image without fusing the characters of NDVI. This method provided a new way for high precision extraction of forest cover.

Abstract:High-standard farmland construction is a strategic deployment to protect the high quality cultivated land and ensure food security. It is a prerequisite for scientific and efficient construction of high-standard farmland to set rational planning of construction sequence and spatial layout. According to the requirements of high-standard farmland construction, firstly, an index system was established to response to cultivated land comprehensive quality. Secondly, TOPSIS model was chosen to evaluate the high-standard farmland construction priority in the grid environment. Thirdly, hotspot analysis method was adopted to zone high-standard farmland construction priority areas into top priority areas, the secondary priority areas and the unfavorable construction areas. The results showed that it was suitable to construct high-standard farmland in the central and southwestern areas of Zhuozhou City, where cultivated land site condition and infrastructure condition were better. These areas were zoned into top priority construction areas and the secondary priority areas, with area proportions of 384% and 318%. It was unsuitable to construct high-standard farmland in some township of western and eastern regions. The results can provide scientific guidance for zoning high-standard farmland construction priority areas and indicate the direction of land consolidation.

Abstract:Landscape pattern determines the local distribution of resources and habitats, which has an important impact on a variety of ecological processes. Based on the full understand of the coupling relationship between landscape pattern and ecological processes, landscape pattern optimization is aimed at achieving the maximum ecological benefits through the adjustment of the landscape patches’ spatial distribution and size. In order to consider more factors in landscape pattern optimization and make the optimization results more scientific and reasonable, an SFLA-M-L model was built based on shuffled frog leaping algorithm (SFLA), logistic regression model and Markov model. The landscape pattern of Dengkou County, Bayannaoer City, Inner Mongolia was optimized to verify the model. Logistic regression model was used to analyze the landscape pattern suitability based on DEM, slope, under ground water depth, aridity index, NDVI and current landscape distribution. Markov model was used to build the landscape transition probability matrix. The objective function of SFLA-M-L was built based on the landscape suitability atlas and landscape aggregation index. Landscape pattern transition probability matrix was used to restrict the transfer of different landscape types. In the optimization results, the landscape aggregation index was 96.71%, which was 6.43 percentage points higher than the landscape pattern in 2016;landscape suitability index was 96.23%, which was 4.18 percentage points higher than the landscape pattern in 2016;the transfer area beyond the control of landscape pattern transition probability matrix was only 4.66km2，and the rationality of the optimization results was ensured.

Abstract:Vegetation temperature condition index (VTCI) combines normalized difference vegetation index (NDVI) and land surface temperature (LST), and is applicable to a more accurate monitoring of droughts in Guanzhong Plain, Shaanxi Province, China. Quantile regression is a tool for comprehensively reflecting the conditional distribution characters under different quantiles, and its regression results are steady and reliable. In order to achieve a better correlation between winter wheat yield and the weighted VTCI as well as a higher yield estimation accuracy, linear regression models between the weighted VTCI and yields in the cities of Guanzhong Plain in the years from 2008 to 2014 were analyzed by using the quantile regression whose quantiles were set to be 0.1, 0.3, 0.5, 0.7 and 0.9, respectively. These quantile regression results roundly reflected the distribution of the yields under different drought conditions and were beneficial supplement of the linear regression from which the single fitted line and impressionable results from outliers were obtained. The wheat yield estimation model based on the median regression (quantile equalled to 0.5) was used to monitor the wheat yields in the cities of Guanzhong Plain from 2008 to 2014, the average and minimum values of the relative errors and the root mean square errors (RMSE) between the estimated yields and the actual yields were all lower than those derived from the ordinary least square method. Additionally, the characteristics of inter-annual evolution and spatial distribution of the estimated yields using the median regression model were in good agreement with the actual situation, which indicated that the quantile regression was feasible and reliable in the research of winter wheat yield estimation and the relationship between yield and drought.

Abstract:Based on plot experiments of winter wheat in Guanzhong area of Shaanxi Province, canopy hyper-spectral reflectance data was collected at different winter wheat growth stages. Seven absorption features were calculated based on continuum removed spectra of original canopy spectrum, which were used to explore the quantitative relationship with leaf nitrogen content. The results showed that continuum removed processing enlarged the small differences inherent in original canopy spectra and absorption characteristics controlled by nitrogen stress. The continuum removal spectra obviously improved the correlationship between original canopy reflectance and leaf nitrogen content. It was negatively correlated with leaf nitrogen content in 721~727nm with determination coefficient of -0.851. The absorption characteristics parameters improved the leaf nitrogen estimation accuracy compared with sensitive bands, and the estimation accuracy by absorption parameters in 550~770nm performed well than that by the variables in 400~550 significantly. Between all the absorption parameters in 550~770nm and 400~770nm bands, the total absorption area, left absorption area, right absorption area and area normalized maximal absorption deep gave more stable achievements than the others, and passed the significant test at P<0.01 level with absolute value of correlation coefficient over 0.8. The best prediction model was built by total absorption area in 550~770nm with determination coefficient of 0.82 with exponential formation. Accuracy test also confirmed the conclusion that the prediction model by total absorption area in 550~770nm was more suitable for estimating the leaf nitrogen content of winter wheat quantificationally.

Abstract:The experiment with micro plots under automatically inductive type of rain preventing condition was carried out to analyze the influence of regulated deficit irrigation on root and crown growth, characteristics of dry matter distribution, water consumption, root-shoot ratio and the wound flow of maize plant. Choosing the relative water content (the percent of field water-holding rate ) of soil as the upper and lower controlling limits, five treatments of water deficit were set, which were respectively the mild treatment（60%～70%FC） and the moderate treatment （50%～60%FC） at seedling stage, the mild treatment (60%～70%FC） and the moderate treatment （50%～60%FC） at jointing stage, moderate treatment at seedling stage and mild treatment at jointing stage, and the appropriate water content （70%～80%FC）was set as control in the whole growth period. The result showed that the regulated deficit irrigation did not change the total tendency of growth of root and crown of maize and the basic tendency of the growth of different organs in crown, but it increased the root-shoot ratio of plant and the distribution ratio of dry matters to ear in later stage of growth obviously, accelerated the transportation and distribution of photoassimilate to reproductive organs and enhanced the compensatory growth of root and crown after rehydration. The mild and moderate treatments at seedling stage of maize sustained higher root quality during deficit period, remarkably increased the root activity after rehydration, showed super compensatory effect of wound flow, kept higher wound flow at filling stage and sustained higher root-shoot ratio in later growth period, which was the appropriate water deficit treatment for coordinating the relationship of the growth of root and crown of maize.

Abstract:In order to investigate water-salinity distribution characteristics in wetted soil of moistube fertigation, the infiltration experiment of moistube irrigation was carried out under different pressure heads and soil bulk densities, the 0.3% potassium nitrate solution was used in infiltration experiment, and three pressure heads (H1.0:1.0m, H1.5:1.5m and H2.0:2.0m) and three soil bulk densities (D1.00:1.00g/cm3, D1.15:1.15g/cm3 and D1.30:1.30g/cm3) were designed to study the water-salinity distribution and spatial variation traits in wetted soil of moistube irrigation. The results showed that pressure heads and soil bulk densities had significant effect on average contents of moisture, NO-3N and K+ in wetted soil. Under the same soil bulk density, compared with H1.0, the sectional area of wetted soil of H1.5 and H2.0 was increased by 13.50%~21.61%, average contents of moisture, NO-3N and K+ were increased by 3.69%~10.71%, 7.80%~10.95% and 7.29%~17.49%, respectively, and uniformity coefficients were increased by 7.65%~18.63%, 5.22%~13.63% and 9.34%~21.89%, respectively. Under the same pressure head, compared with D1.00, the sectional area of wetted soil of D1.15 and D1.30 was decreased by 5.76%~9.21%, average contents of moisture and NO-3N were decreased by 15.73%~21.54% and 8.08%~10.97%, but average content of K+ was increased by 34.89%~64.79%, and uniformity coefficients of moisture, NO-3N and K+ contents in wetted soil were decreased by 9.02%~11.45%, 4.04%~7.25% and 7.09%~11.54%, respectively. K+ distributed intensively around moistube and accounted for 40.80%~61.41% of distribution area of wetted soil. Average contents of the moisture, NO-3N and K+ in wetted soil of moistube irrigation and the horizontal distance from moistube conformed to the four-parameter Log-logistic model. The research results can provide theoretical basis and practical reference for moistube fertigation.

Abstract:The physical and chemical properties of magnetized brackish water changed significantly, so irrigation with such water is likely to influence the characteristics of soil water and salt movement. The constant magnetic water device with magnetization intensity of 300mT was used to magnetize brackish water with different salinities (0.14g/L，2g/L，3g/L，4g/L and 5g/L), and one-dimension vertical water infiltration experiment was conducted to reveal the effects of salinity of magnetized brackish water on water and salt movement in soil. Results showed that the soil infiltration rate and wetting front migration rate were decreased significantly with irrigation by magnetized brackish water, whereas the moisture content of the wetted zone was increased significantly. The salinity of brackish water had significant impact on the magnetic effect. When the salinity of brackish water was 3g/L, the relative reductions of cumulative infiltration and wetting front depth reached the maximum, and the relative increase of moisture content of wetted zone reached the maximum at the same infiltration time. Magnetized brackish water had significant impact on the parameters of Philip and Green-Ampt formulas. The soil sorptivity S, the saturated hydraulic conductivity Ks and the wetting front suction of magnetized brackish water were all less than those of the non-magnetized brackish water. There was significantly quadratic polynomial relationship among the relative sorptivity ΔS, the relative saturated hydraulic conductivity ΔKs and the salinity of brackish water. When the salinity of brackish water was 3g/L, the relative sorptivity ΔS and the relative saturated hydraulic conductivity ΔKs reached the peak value. Moreover, magnetized brackish water could enhance soil water retention capacity, thus the soil moisture content was increased significantly in the same soil depth. Magnetized brackish water could improve the desalination efficiency. In the soil depth of 0~20cm, the desalination efficiency of brackish water was greater than that of the non-magnetized brackish water, and when salinity of brackish water was 3g/L, the magnetic salinity intensity was the strongest, and the relative desalination effect turned out to be better.

Abstract:Aimed to reveal the distribution characteristics of different land use types, six land use types were chosen, including citrus orchard (CO), forest land (FL), wheat dry land (WD), vegetable dry land (VD), vegetable greenhouse land (VG) and paddy land (PL) as the research objectives in the typical watershed in Three Gorges Reservoir region. The contents and distribution characteristics and pollution evaluation were all analyzed, the results showed that the order of Pb contents changed from high to low were VG, CO, PL, VD, FL and WD, the Cr contents changed from high to low were CO, VG, PL, VD, FL and WD, the Cu contents changed from high to low were VG, VD, CO, PL, FL and WD, the Zn contents changed from high to low were CO, VG, PL, WD, VD and FL and the Cd contents changed from high to low were VG, CO, WD, PL, VD and FL. Meanwhile, there existed obviously positive correlation between Pb content and Cr, Cu, Zn and Cd contents（p<0.01）, there also existed obviously positive correlation between Cr content and Cu, Cd contents（p<0.01）and there existed positive correlation between Cr content and Zn content（p<0.05）. The estimation of single pollution index of these five soil heavy metals, i.e., Pb, Cr, Cu, Zn, Cd contents of the six land use types changed from high to low were 0.06, 0.14, 0.15, 0.14 and 1.70. And the comprehensive pollution index was 0.91, the pollution degree belonged to guard line and the pollution level was the Ⅱ level—relative clean. Meanwhile, the order of the six land use type of soil heavy metals changed from high to low were VG, CO, VD, PL, WD and FL. The results of the potential ecological risk index indicated that the soil heavy metals Pb, Cr, Cu and Zn belonged to light ecological risk. However, the soil heavy metal of Cd belonged to middle ecological risk in the forest land, dry land of wheat and paddy land, Cd belonged to a bit strong ecological risk in the citrus orchard, vegetable dry land and vegetable greenhouse land. And the potential ecological risk index of these five soil heavy metals changed from high to low were Cd, Pb, Cu, Cr and Zn. 

Abstract:An indoor experiment was conducted to investigate the characteristics of the unsaturated horizontal infiltration and wetting front advance in cracked yellow cinnamon soil, by incorporating different densities of straws to simulate the different growth stages of crop root, combined with digital image processing and Matlab morphology algorithm. The results showed that the stable forms of soil crack were significantly different in treatments of different straw incorporations（p<0.05）. A downward trend in crack area ratio and crack width (respectively decreased to 1.73% and 0.071cm) was observed with the increasing straw incorporation from 0cm/cm3 to 1.5cm/cm3. Fracture area density and the average crack width of soil stable forms were significantly decreased with straw density increased. The discharge time of horizontal infiltration was affected by the degree of soil cracking. Cumulative infiltration into uncracked soil and cracking soil changed with time was in line with the empirical model proposed by Kostiakov, the parameters of which were closely related to straw densities. The changes of fitting equation reached significant level. The uniformity coefficient of the wetting front was introduced to evaluate the non-uniformity of the horizontal absorption. The initial nonuniformity was more obvious with the increase of soil crack area density and average crack width. The uniformity coefficient was decreased with time. The greater the crack area and the average crack width of soil were, the more obvious the characteristics of nonuniformity in initial stage of infiltration became. According to the changing characteristics of the wetting front forward speed changed with time, the horizontal infiltration process in cracked soils can be divided into three stages: the initial stage of crack flow, the stage of steady matrix flow and the late stage of horizontal infiltration.

Abstract:Many problems, such as the shortage of water resources and the low operating efficiency of water project, are ubiquitous in an irrigation district with multi-water resources. Therefore, it is significant and necessary to implement joint dispatching of multi-water resources to alleviate water shortage and promote the synergy ascension of water resources productivity. Taking Heping irrigation district in Heilongjiang Province as an example, a fuzzy multi-objective programming for multiwater resources optimal allocation model was constructed. The proposed model was capable of increasing water net benefit and decreasing water-use amount simultaneously, which would improve the effective allocation of multi-water resources of Heping irrigation district. Fuzzy multiobjective programming with nonlinear membership functions was adopted to solve the model, and the optimal water allocation schemes under different flow levels and water sources were obtained. Results showed that water shortage existed in each growth period of rice under each flow level, and more water should be transferred from Liuhe reservoir under low flow level to guarantee the minimum water requirement. Water were allocated to rice in the order of water diversion project, water lifting project and well irrigation project to ensure the total benefit of Heping irrigation district. The stability of the multi-objective model operation under different scenarios was obtained and analyzed in detail. Water allocation of water diversion project was relatively stable, while water allocation of well irrigation project had higher sensitivity for nonlinearity of membership function of the objective function under low flow level. The developed model can effectively allocate multi-water resources to the different growth stages of rice, which would provide reasonable decision schemes for the corresponding administrative departments.

Abstract:Plastic film mulching, known as the “white revolution”, has been widely used in cotton cultivation in China, since it makes the cotton planting area expanded from the south toward the north and from the east toward the west. However, it is unclear about if and how the yield increasing effect of plastic film mulching is influenced by different planting patterns, climatic factors, film thicknesses, regions and experimental durations in China. To solve these questions, a total of 29 papers containing 48 groups of data were selected on the subject of cotton yield and plastic film mulching from the published papers before 15th November, 2016 and analyzed by metaanalysis. The main steps included heterogeneity test, comprehensive effect size calculation, publication bias test, sensitivity analysis, cumulative metaanalysis and influence factor analysis. Results showed that there were no publication bias and no extreme value among the collected data, thus the analysis results were highly credible. Plastic film mulching averagely increased cotton yield by 17.2% compared with no mulching. The cumulatively average yield of cotton mulched with plastic film was increased by 1.2%~18.0% since 1986. Under flat planting, in regions where annual mean temperature was lower than 12℃ or annual precipitation was less than 500mm, and using 0.008mm plastic film, the yield increasing rate under plastic film mulching was higher, which was 17.8%, 21.5%, 19.1% and 17.3%, respectively. The yield increasing effect with plastic film mulching was the highest in the northwest region with a mean value of 24.5%, followed by the Yellow River Basin with a mean value of 16.5%, then by the Yangtze River Basin with a mean value of 10.5%. In recent years, plastic film mulching could improve cotton yield to a certain extent, but its yield increasing rate was declined, and necessary measures needed to be taken. This research would provide valuable information for the application of plastic film mulching and further increase the yield of cotton in China.

Abstract:Totally nine experimental treatments for cherry trees with different water-fertilizer amounts were established through fertigation with drip irrigation method, based on which the soil moisture and physicochemical property of cherry orchard were measured, as well as output and quality of cherry fruit under different treatments. Results showed that under different treatments, during the whole growth period of cherry trees, soil moisture content had a downward trend;during the irrigation period, the more the irrigation amount was, the higher the moisture content of shallow soil was, and it had no obvious influence on the deep soil. Water-fertilizer conditions under such experimental treatments can significantly improve the fruit quality. Higher fertilizer amount can increase fruit diameters;appropriate water amount can significantly improve the fruit hardness;higher fertilizer amount and lower water amount can reduce the content of titratable acid;lower water and fertilizer amounts can increase the soluble solid content;middle-level fertilizer amount and lower water amount can increase the crude protein content;lower water and fertilizer amounts can increase the vitamin C content of fruit, and appropriate water amount and lower fertilizer amount can increase the content of total soluble sugar. The linear relations between various indexes of soil nutrients and microelements of cherry fruit were comprehensively analyzed, and the sensitivity analysis regarding various indexes of soil nutrients and fruit quality was conducted by introducing Spearman rank correlation coefficient method. Ammonium nitrogen and nitrate nitrogen contents in soil were under instable conditions and no clear rules were found in nutrient changes;among various indexes of soil nutrients, the organic content had positive correlation with full iron content of fruit;the content of available ammonium nitrogen had positive correlation with total chlorine content;content of available nitrate nitrogen had positive correlation with contents of total calcium, zinc and chlorine of fruit;content of available phosphate had positive correlation with full iron content;content of rapidly available potassium was negatively correlated with full calcium content. Among soil nutrients, ammonium nitrogen and nitrate nitrogen had close relations with most indexes of fruit quality.

Abstract:With different biochar amount levels of 0t/hm2, 25t/hm2, 50t/hm2, 75t/hm2 and 100t/hm2, the runoff plots experiments were conducted to study the influences of biochar supply on the indexes of soil physicochemical properties, water holding capacity, soil and water conservation and the effects of water-saving and yield-increasing, and a model was established based on Gumbel Copula function for black soil productivity evaluation under different straw biochar amounts. The results showed that with the increase of straw biochar amount, the soil bulk density was decreased and porosity were increased, the soil nutrients distribution was uniform. Available P and K, pH value and organic matter content were increased linearly, and ammonium N was increased exponentially. Saturated soil moisture, field capacity, wilting coefficient and the maximum effective water content were all in positive correlation with the straw biochar amount, and the influence degree of high biochar amount on soil moisture was more significant than that of low biochar amount. With the increase of straw biochar amount, the amounts of annual runoff and soil erosion were all decreased linearly, the reduction rates of runoff and sediments were increased logarithmically, while the soybean yield and water use efficiency were increased firstly and then decreased like a parabola going downwards. The evaluation model based on Gumbel Copula function was used to evaluate the soil productivity under different straw biochar amounts, and the result was reasonable. The soil productivity index calculated by the model was increased with the increase of straw biochar amount in an S-shaped curve, the indexes of soil physicochemical properties, water holding capacity, effect of soil and water conservation were increased linearly, and the indexes of water-saving and yield-increasing were increased firstly and then decreased in a parabola shape. 

Abstract:In cold region of China, problems exist in the study of hydrological models, including lack of basic data, low spatial and temporal resolution of available data and the difficulty of quantitative calculating evapotranspiration, snow cover and snow melting. In response, grid-based Sacramento (GSAC) model was selected, different land cover change scenarios were set, effects of land cover change on runoff were analyzed quantitatively, and runoff in dry season was predicted. Results showed that in simulating the daily runoff of Baoqing River Watershed in cold region with model which had parameters calibrated, the average determination coefficient was 0.7329 during the periods of calibration and validation, which well reproduced the daily runoff of this watershed during 1997—2001;returning farmland to grassland or forest can both increase the annual runoff, with the growth rate between 3.09% and 44.85%, and the growth rate of returning farmland to grassland had more influence on runoff;the steepness of land returned to grassland or forest had negative correlation with the runoff at the watershed export section, i.e., the smaller the slope was, the greater the flow was;the average runoff of farmland with steepness over 15° after being returned to grassland was similar with the ecological water demand in this area.

Abstract:A new numerical model of sand-wind interaction was proposed to predict the surface morphology evolution and provide the basis for dimension design of sand barrier. Based on the theory of probability and statistics, the model realized sand-wind interaction process by calculating wind erosion and deposition probability of sand grains at different wind speeds. Firstly, the model parameters of air phase and sand phase were initialized, and the velocity distribution can be calculated by computational fluid dynamic (CFD) method. Secondly, the wind friction velocity of sand element was calculated by using velocity field data, and the sand transport rate can be obtained. Finally, the thickness of sand element was calculated by calculating sand change in one time step. The moving mesh technique was used to change the fluctuation of the sand bed by changing the coordinates of lower boundary nodes. The numerical results were compared with the measured results, which showed that the numerical results of the surface morphology in the sand barrier were close to the measured results. The lowest point of pit was the maximum position that moved along the downwind area, the average absolute error was 17.86% when t=4d, the error was decreased gradually with the increase of sand accumulation, the average absolute error was 8.52% when t=8d. Both qualitative and quantitative results were consistent with the measured results, and the model can simulate the surface morphology evolution of sand barrier correctly.

Abstract:Instability of high solid-state anaerobic digestion often happened during the longterm operation of reactor. To investigate underlying methanism of this problem, the characteristics of semicontinuous anaerobic digestion for rice straw were studied with three organic loading rates (OLR) in a horizontal reactor, when being co-inoculated with ruminal contents and anaerobic sludge. The results indicated that the highest volume biogas production reached 1.04L/(L·d) in the reactor. The average CH4 productivity reached 280.90mL/g VS with 54.39% CH4 volume content at the OLR of 2.26g/(L·d), which was up to 80.29% of the theoretical value of rice straw. The highest digestion rates of hemicellulose and cellulose were 49.71% and 31.25%, respectively. And the cellulase activities were increased obviously in the horizontal reactor, which was indispensable to the degradation of cellulose. At the OLR of 2.47g/(L·d), the average concentration of ammonium nitrogen reached 1082.63mg/L. Especially the highest concentration reached 1196.37mg/L after 192d of operation. It was indicated that the methanogens suffered different influences from ammonium nitrogen using quantitative realtime PCR(Q-PCR). Specifically, the hydrogenotrophic Methanobacteriales was decreased to 1.04×106 copies/g from 1.70×109copies/g dominated in the solid residues and CH4 productivity was decreased to 256.54mL/g for being inhibited significantly. In contrast, the acetotrophic Methanosarcinales was increased to 9.44×106 copies/g from 7.89×106 copies/g. At the same time, the average propionate concentration reached 253.32mg/L in the anaerobic reactor. Thus the study revealed the adaptive shifts of underlying methanogenic communities by ammonium nitrogen inhibition during the high solidstate digestion of rice straw.

Abstract:A CO2 concentration monitoring system targeting greenhouse application was designed, which included sensor nodes, CO2 concentration regulation node, wireless communication and PC terminals. A remote real-time CO2 concentration measurement was realized by using an infrared CO2 model S300 as the core model in sensor node. Environmental information derived by sensor nodes was transmitted to the PC software panel based on LabVIEW through wireless sensor networks. Received signal strength indication (RSSI) was sampled in transmission to ensure link quality and extend the service lives of sensor nodes by reasonably adjusting the transmission power. The designed and fabricated sensor node was calibrated and characterized by the standard CO2 samples distributed under laboratory conditions. The experiment results indicated that the limitation of detection of the selected sensor was lower than 5×10-5. The fluctuations for the long-term stability measurements on a 3×10-4 CO2 sample and a 6.5×10-4 CO2 sample were less than 2.6%. This designed monitoring system was deployed in the Guoxin picking garden in the town of Sheling, Shuangyang District, Changchun City, Jilin Province, and the field experiment was carried out in a solar greenhouse whose area was 640m2. The desired CO2 concentration in greenhouse was set to 8×10-4, the fluctuation range under controlled CO2 concentration was nearly (8±0.42)×10-4.The designed sensor node had advantages, including miniaturization, cost-effective and high precision, which realized intelligent management, remote synchronization of greenhouse factors and smart regulation of CO2 concentration in greenhouse.

Abstract:A remote monitoring system for farmland based on wireless image sensor network was put forward in order to obtain the farmland image and video information in real time. Aiming at the shortcomings of the current image sensor nodes, a low-cost high-resolution wireless image sensor node was designed based on CMOS image sensor chip and S3C6410 embedded processor. To ensure the stability and reliability of the node, the powerful embedded Linux operating system was employed as the software development platform. And based on this platform, a modular designing method was adopted to program the software system of the node in C/C++ language. Especially, a resolution adjustment algorithm based on driver and application layer cooperation was studied, which made the node had 10 different resolutions and the highest resolution was up to 5 mega pixels. More importantly, the resolution can be adjusted in real time according to the requirements of users when it was working, which made the node can meet the needs of users for different image accuracies. A wireless image sensor network was constructed by utilizing WiFi technology as well as the images and videos captured by the nodes were remotely transmitted to the server through the 4G network. In order to prolong the life cycle of the node, a solar power supply system was designed. A visual farmland information management software Webbased was developed in order to effectively store, manage and use the data captured by the nodes, and a convenient method was provided for a user to remotely access the acquisition networks and the data stored in the server. The system was deployed and tested for a long time. The test results showed that the system could work stably, as well as capture and transmit images with different resolutions according to the remote instruction. Moreover, the average time to capture and transmit one image with size of about 126KB was about 5.36s, and the average packet loss ratio of the network was about 1.67%. In the tests, the average delay for the client to open video monitoring was about 3.48s, and the video playing was smooth. Finally, the power supply system based on the solar energy could provide a stable power supply for the nodes in the long work. The tests validated that the remote monitoring system designed in this work can automatically capture images and videos of farmland in real time, transmit them to the server remotely, and satisfy the requirement of users for remote monitoring farmland.

Abstract:Seven Sanhuang chicken carcasses, which were 50d old and the carcasses weight was in the range of 1.741~2.508kg, were selected as experimental samples. Their body size parameters, eviscerated weight, main organs weight and viscera weight were measured and then the relationships of these parameters with the carcass weight were analyzed and investigated. After the sample’s crosssectional images were captured by using a spiral CT machine, the relative positions of heart, lung, stomach, kidney and other major viscera were observed and in the same time, the visceral cavity size and the position and size of the eviscerated incision were estimated according to these images. Experiment results showed that their breast depth and shank length were gradually increased with the raise of carcass weight of Sanhuang chicken. Furthermore, the body length, breast width and shank circumference were significantly increased (P<0.01) linearly as the carcass weight was increased. The weight of heart, lung, stomach muscle and kidney also showed a trend of increase with the rise in carcass weight, which had certain relevance. In addition, the relative position of the heart, lung, muscle stomach and kidney could be clearly determined based on the horizontal and vertical crosssectional CT images of carcass;for the Sanhuang chicken samples with carcass weight distribution of 1.741~2.508kg. The estimated cavity size was (15.560±0.540)cm long, (7.22±0.253)cm wide, and the maximum incision length was (4.783±0.467)cm.

Abstract:A rapid detection method for reveratrol content in red wine was built by hyperspectral imaging technology combined with fluidized bed preconcentration technology. The reveratrol content in red wine was determined by high performance liquid chromatography. An enrichment apparatus of fluidized bed was built to explore the enrichment effects, which five macroreticular resins, such as HPD826, DA-201, AB-8, H103 and HPD600, enriched reveratrol in red wine. The result showed that H103 resin had the best enrichment effect. H103 resin was used to enrich resveratrol from wine, the 900~1700nm spectral images of resins which absorbed reveratrol were collected. Compared with five spectra preprocessing methods (MSC, SNV, SG-S, RN and QN), RN was selected as the best method for modeling effects of resveratrol content. Then, six regression models based on PLSR, SVMR (LK-SVMR, PK-SVMR, RBF-SVMR and S-SVMR) and PCR were established. Correction models based on LK-SVMR and PLSR were selected to evaluate their accuracy and stability in prediction sets. Finally, the PLSR model was chosen as the best model. The research showed that the quantitative prediction model of resveratrol in red wine based on PLSR obtained the best prediction effect, its RP was 0.8528, RMSEP was 0.0360, RC was 0.8783, and RMSEC was 0.0330. The results provided references for the detection of trace components by hyperspectral technology.

Abstract:After 3d or 5d storage at temperature of (3±0.5)℃ under high oxygen atmosphere, Agaricus bisporuswas packaged (modified atmosphere packaging) and placed at (3±0.5)℃ (simulated supermarket fresh cabinet) and (20±0.5)℃ (simulated room temperature sales). The objects were to research the subsequent effects of high oxygen atmosphere on the shelfquality of Agaricus bisporusby measuring the whiteness, hardness, weight loss rate, respiration rate and soluble sugar content. Results showed that Agaricus bisporus after treatment in high oxygen atmosphere could still maintain good quality at (3±0.5)℃. The effect was better than that stored under high oxygen environment all the time. The quality of Agaricus bisporus stored after 3 d was better than that after 5 d. The best quality appeared after treatment in 80% O2.The quality of that refrigerated for 5d at (20±0.5)℃ was the best, which was followed by those of 100% O25d, 100%O23d and refrigerated for 3d. The quality deterioration of Agaricus bisporuswas accelerated under 80%O2 treatment at (20±0.5)℃. Therefore, the results indicated that the subsequent effects on the shelfquality of Agaricus bisporus stored in 80% O2 had preferable influence, while the quality deterioration at (20±0.5)℃ was obvious. When placed at (3±0.5)℃ and (20±05)℃, the packaged Agaricus bisporusafter treatment in 80% O2 were obviously different in whiteness. By comparison, the packaged Agaricus bisporus after treatment in 100% O2and refrigerated was more suitable to distribution at ambient temperature. Thereby, the research provided certain theoretical basis for the preservation and sale of Agaricus bisporus.

Abstract:With the aim to explore the effects of apoptosis on muscle internal environment, apoptosis factors and tenderness during postmortem aging, the longissimus dorsi muscles injected with specific inhibitor cyclosporin A (CsA) of MPTP were taken as experiment objects. The muscle internal environment factors, apoptosis factors and tenderness index were measured. The results indicated that myofiber diameter and cross section area in the CsA group were significantly or extremely significantly larger than those in the control group (P<0.05，P<0.01);after 6h and 72~120h of postmortem, the pH value in the CsA group was lower than that in the control group (P<0.05), and at 6~168h of postmortem, ATP contents in the CsA group were higher than those in control group, specially, after 12hand 72~168h of postmortem, ATP contents in the two groups had significant difference (P<0.05);the degree of MPTP opening in the CsA group was lower than that in the control group (P<0.01);Cyt-c content in the cytoplasm was significantly or extremely significantly lower in the early aging stage, and the result was opposite in the late aging time;caspase-3 activities in the CsA group was lower than those in the control group during the whole time except after 72~120h of postmortem;Hsp27 expression in the CsA group was lower than that in the control group, after 12~24h of postmortem, the shear force of the CsA group was higher compared with the control group. Cyclosporin A could suppress the changes of internal environment, caspase-3 activities, Hsp27 expression level and the shear force and changes of myofibrils and mitochondrial ultrastructure by suppressing the opening of MPTP, the apoptotic process played a significant role in the changes of internal environment and yak meat tenderness during postmortem aging and the changes of internal environment and tenderness could be adjusted by controlling the apoptosis process.

Abstract:Yak meat is rich in nutrients, but has low water-holding capacity (WHC), which affects its edible and processing quality. Therefore, control of postmortem juice loss and reduction of economic loss are crucial issues needing urgent resolution in the yak meat processing industry. Existing research suggested that changes in proteins affected the WHC of postmortem muscle, but relevant mechanism was still not entirely clear because of the complexity of protein composition. Thus, it is very important to explore the variation mechanism of postmortem WHC of yak meat by combining multiple analytical and testing methods. Proteomics research combined with bioinformatics approach was studied by comparing high-WHC (HWHC) and low-WHC (LWHC) groups. Based on the data obtained from drip loss and cooking loss, totally 18 longissimus dorsi of yak can be classified into HWHC and LWHC groups. Totally six proteins were found to be abundant differentially between HWHC and LWHC groups and identified by matrix assisted laser desorption ionizationtime of flight/time of flight (MALDI-TOF/TOF). Matched spots exhibited a three fold or more intensity difference in the meantime associated with 5% statistical significance (P<0.05). Then hydrophobicity analysis and subcellular localization prediction were used to validate the representative proteins. Results showed that differentially abundant proteins were lactate dehydrogenase (LDH), creatine kinase M-type (CKM), triosephosphate isomerase (TIM), myosin light chain (MLC), troponin T (TnT) and heat shock 27kDa (HSP27). The analysis of hydrophobicity performed that LDH, CKM and TIM had more hydrophobic regions. The results showed that the high hydrophobicity could enhance the rejection of protein and water, which might lead to the weak water retention of yak meat. In subcellular localization prediction, the differentially abundant proteins in the cells were divided into five positions. All of the differentially abundant proteins were located in the cytoplasm and nucleus. Accordingly, proteomics and bioinformatics analyses were proven to be excellent tools to quantify the changes of proteins and biological information linked to WHC, and thus helping to explain the processes behind characteristic meat quality traits in yak muscle.

Abstract:In order to quickly identify different taste qualities of beef juices and divide the quality grade of beef individuals, a taste sensor array was built by the method according Byrd Luo taste theory, containing twelve working electrodes and one reference electrode. The array was applied to classify the quality grade of beef juices, and 30 groups of beef juices were distinguished. The method of clustering analysis based on Euclidean distance was used to classify the taste quality of beef, which showed that the taste characteristics of the same grade of beef juice samples were very similar and could be aggregated into one group. And the accuracy of sensor array to detect the beef taste quality was assessed by sensory evaluation. The sensor array for identification of beef juices was optimized for the key technical issues of automated quality evaluation of beef juices. The inherent relationship among the response signals of sensors was analyzed by the factor analysis of variance. Six working electrodes (S1, S2, S5, S7, P2 and P3) were selected to compose beef taste sensor array with the reference electrode, and 30 groups of beef juices were identified. The results showed that the identification accuracy rate for beef juices by the optimized sensor array was 93.33%, which was higher than 80.00% by the non-optimized one.

Abstract:Effect of different physical modification conditions (heating treatment, ultrasound treatment, highpressure treatment, homogenization treatment and microwave treatment) on emulsifying properties and flexibility characterized by sensitivity to trypsin of soy protein isolate was investigated. The correlation analysis between flexibility and emulsifying properties (emulsifying activity and emulsion stability) was also investigated. The results suggested that different physical modification methods had different effects on flexibility and emulsifying properties of soy protein isolate, and emulsifying activity and emulsion stability were increased with the increase of flexibility. The best flexibility and emulsifying activity were got at 121℃ with 10min heating treatment, comparing with other physical modification conditions. Highpressure homogenization treatment had little impact on flexibility but it had great impact on emulsifying activity. Correlation analysis suggested that soy protein isolate flexibility was very significantly and positively correlated with emulsifying activity and emulsion stability under heating and ultrasound treatment conditions, correlation coefficients were 0.969, 0.950 and 0.942, 0.954, respectively. Flexibility of soy protein isolate was positively correlated with emulsifying activity and emulsion stability under highpressure treatment conditions, correlation coefficients were 0.771 and 0.720, respectively. Flexibility of soy protein isolate was very significantly and positively correlated with emulsifying activity and emulsion stability under microwave treatment conditions, correlation coefficients were 0.976 and 0.862, respectively.

Abstract:With the development of new-energy vehicles, braking energy recovery as an important means to save energy and protect environment of the new-energy vehicles causes attention widely. The control strategy of braking energy recovery based on electric servo system was studied. Firstly, the operational principle and key components of the electric servo system were analyzed and the braking modes were divided based on the vehicle speed and braking intensity. Secondly, the distribution strategy of braking force considering the economy and security of the vehicle was researched. The motor braking force was corrected by using the intensity of the brake, vehicle speed and SOC. The control theory of pressure was analyzed and control requirements were provided. The pressure-control strategy was studied based on the feedforward and feedback, aiming to control the pressure precisely and validate the control results of pressure by using Matlab/Simulink and AMESim co-simulation. Finally, the control strategy of the braking energy recovery was validated by the real-vehicle test and the economy of the vehicle was evaluated by using the rate of braking energy recovery. The rate of braking energy recovery of NEDC cycle can reach 71.38%. The results showed that the distribution strategy of braking force and the pressure control algorithm were valid and feasible and the control strategy of braking energy recovery can increase the rate of braking energy recovery and raise the economy of the vehicle significantly. Therefore, the control strategy of braking energy recovery based on electric servo system was valid and feasible. The control strategy presented can provide a useful reference for the design of braking energy recovery system for electric vehicles.

Abstract:Due to the mutual restricted problem among comfort, safety, energy-regeneration in single control mode, the hybrid suspension with four working modes was designed and the switching strategy based on model reference was generated to control linear motor and adjustable damping to switch. Comfort model, safe model, combine model and passive energy recycle model were proposed to solve the above problems. And the body acceleration and tire dynamic displacement were used as the threshold of these four switching modes. In this system, the hybrid suspension with linear motor and three stages adjustable damping was taken as the research object. First of all, control strategies in different modes were changed through the use of multi-mode switching to improve the control effect. Then in order to reduce energy consumption and recover energy, the appropriate damping values in different modes were selected and the linear motor was used as a generator. And based on Simulink/Stateflow, the switching control system of 1/4 hybrid suspension was designed and simulated, and a complete simulation process from road switching, mode selection, mode switching to the changing of suspension model parameters was constructed. And a rapid prototype experiment was carried out. The experimental study on dynamic performance and energy feedback capability of hybrid suspension was based on dSPACE development model. The corresponding control strategy was designed and the results indicated that the root mean square value of the body acceleration and the root mean square value of the tire dynamic displacement were compared with the simulation results. Multi-mode switching control model of the hybrid suspension can effectively switch and reach the switching target, help hybrid suspension with energy recovery and improve the comprehensive performance of the hybrid suspension.

Abstract:In order to improve the four-wheel drive vehicle dynamic performance and running stability, an axis torque distribution control strategy was proposed through real-time observation of front and rear shaft speed difference and wheel slip ratio of the car. The vehicle dynamics model was constructed through the Matlab/Simulink, including transmission system model, tire model and sub-modules like slip ratio calculation module and motor model. The inter axle torque distribution control system and application was designed based on genetic algorithm (GA) and the PID control. On the low adhesion uniform pavement, docking road face to speed up performance of vehicle was simulated and analyzed. The hardware and software design of the shaft torque control system was carried out, and the development of the shaft torque control system was done, and the development of the controller was verified by the road test. The hardware and software design included the controller circuit and power circuit, and the control system of PCB harware increased the anti-interence design. Taking CodeWarrior as platform, the control system software framework, CAN bus communication program, data acquisition program, PWM driver were designed. The result showed that the controller and the control strategy can follow the real-time road conditions well, so that the vehicle dynamic performance and stability were improved. The test result also verified the effectiveness of the control system.

Abstract:Aiming at the difficulty of using accurate analytical formulas to represent the Tripod parallel robot workspace boundary surfaces, a method called surface-sweep analysis combined with the shape of mechanical structure analysis was proposed to give an accurate expression to the workspace of Tripod parallel manipulator. On account of the Tripod parallel robot, the geometric model of the parallel robot was set up and the architecture of the parallel robot and the driving mode of the parallel robot were introduced. Based on the algorithm of forward and inverse kinematics solution, the scope of sweeping space and envelope surface expression of this sweeping space considering one of the robot parallel’s open chains were obtained. Then, the six envelope surfaces were drawn in sequence and the overlap part of the six sweeping space was solved. In 3-D software, the public workspace can be obtained by using boolean operation algorithm. Then, under the consideration of mechanical structure of shape analysis and physical constraints, the actual workspace and boundary surface expression of robot can be obtained. Furthermore, the singularity of the obtained workspace was analyzed. According to the comparison of workspace measured by the three coordinate measuring instrument and the workspace obtained by 3-D software, the validity of this analytic method was verified by using the error analysis method, which layed foundation for the next step to figure out the influence of mechanical parameters on the workspace and do some work on the size optimization of the parallel robot.

Abstract:Aimed at 6-DOF modular manipulator, singular configurations was analyzed within its workspace. Firstly, modular manipulator system was constructed, and the forward kinematics model was conducted by using the DH method. Secondly, combining the kinematics equation, the Jacobian matrix was constructed by using method based on link speed of manipulator, and all the singular states of the manipulator was solved through the method of singular decomposition, all the singular points within its workspace were acquired and the corresponding configurations were shown. Lastly, simulation analysis of manipulator with singular configurations was completed based on the manipulability flexible index and the minimum singular value flexible index by means of the robotics toolbox, changing of the manipulability, the smallest singular value and the Jacobian matrix rank of manipulator were shown during each joint rotting within its range, and the manipulability ellipsoid of end reference point of manipulator was explored when manipulator was in singular configuration. The simulation results showed that the manipulator had three singular states within its workspace, and the manipulability and the minimum singular value were tended to zero, the Jacobian matrix was rank-reduced and the position manipulability ellipsoid of end reference point of manipulator was reduced to a plane when manipulator was in each singular states above. Simulation results verified the correctness of the singularity analysis, and laid a foundation for subsequent trajectory planning research and singularity avoidance research of modular manipulator.

Abstract:In order to improve the position precision of moving platform end effector of linear driven parallel robot, based on structure and kinematic model of parallel mechanism, the dimension errors, driving errors and assembly errors of parallel robot which influenced accuracy of the moving platform end effector were analyzed, the non-linear mapping from the actuated variables in joint space to the pose of the end-effector in operating space was established with analytic method. On the basis of the sensitivity error model, an error source selection scheme was proposed according to the global sensitivity evaluation index, which was defined to evaluate the error source on the position error of the moving platform in given workspace, and the main error sources that affected the location accuracy was selected. It was found that the position error of the moving platform was basically the same between all error sources and selected error sources by randomly simulating the dimension errors, driving errors and assembly errors of the parallel robot with Monte Carlo method, which verified the consistency of the evaluation index. By taking laser tracker as measurement tool, the position precision of the moving platform end effector of the parallel mechanism was improved remarkably after detecting the selected main errors of the parallel robot and calibrating the forward kinematic model，which verified the validity and feasibility of the error source selection scheme and reduced the complexity and computation of the error parameter identification. It had greatly important guidance to the error compensation of the complex structure.

Abstract:The inerter can replace the mass block and realize the dynamic characteristic of large inertia body with small mass, thus greatly enriching the design theory of mechanical vibration network. To achieve the same inertance, the larger the inertia-mass ratio is, the lighter the mass of the flywheel is, and the advantage is more obvious. In order to improve the inertia-mass ratio of ball screw type inerter, a new design of ball screw type inerter with planetary flywheel was put forward. By the mechanical model of inerter, the influence of structure parameters on the inertia-mass ratio of flywheel was researched. Result showed that the inertia-mass ratio could be improved by three methods: increasing the number or thickness of the planet gears, reducing the pin diameter, which increased the proportion of planet gear rotation inertia in the total inertia of flywheel. The maximum inertia-mass ratio could be obtained by the optimal gear ratio of planet gear to ring gear, which was calculated by the number and thickness of planet wheel and the pin diameter. The mechanical properties of planetary flywheel inerter were compared with those of traditional inerter. Analysis of result indicated that the inertia-mass ratio of planetary flywheel inerter was larger than that of traditional inerter with the same diameter of flywheel. But for the same radial size, the planetary flywheel was thicker than the traditional-single flywheel. Therefore, the planetary flywheel inerter was suitable for the weight sensitive, and the axial space-rich application occasions. The theoretical analysis was verified by experiment at last.

Abstract:The body wall structure of Clanis bilineata larva exhibits a strong stability under bending load. This characteristic prompted the development of a new inflatable tube to improve the stability under bending load. The Clanis bilineata larva was chosen to observe the connection between its body wall and nearby muscle tissues, as well as the distribution of these tissues, by using the tissue section technique. The Clanis bilineata larva can be simplified as a telescopic cylinder with folds and depressions. A large number of axial muscle tissues were found on the inner cylinder, which were uniformly distributed near the cylinder and divided into several sections in the axial direction. Between adjacent sections, a close connection to the body wall was formed. The distribution of the circular muscle tissues was relatively dense, and the distribution in the reticular structure enhanced the mechanical strength of the whole insect body and improved the stability of the structure. This structure simultaneously became a barrier to reduce impact from the outside world on the internal organs and ensured the normal physiological activities of the Clanis bilineata larva. Inspired by this, an inflatable tube with reinforcing ribs was designed. Simulation using the finite element method and experimentation were employed to analyze the bending characteristics of the inflatable tube with and without reinforcing ribs under different pressures. Results indicated that the ultimate load of both inflatable tubes was increased linearly with the increase of pressure;the existence of reinforcing ribs can improve the bending characteristics of the tube, at the same time, the simulation results showed that the bending capacity of inflatable tube with reinforcing ribs was stronger when loading at 45° angle than that at 0° angle, both of which were higher than that without reinforcing ribs.

Abstract:With the development of digital design and manufacturing integrated technology, 3D CAD model has become the core media of expressing product design and manufacturing information, efficiently locating the desired model from massive candidates, fully exploiting and reusing the implicit knowledge had an important role in improving the mechanical design efficiency and quality in the agricultural equipment field. To effectively realize the reuse of design information of 3D CAD models in design domain, an effective subpart retrieval method of 3D CAD models merging with design semantics was proposed. Firstly, design feature was taken as the basic carrier of design semantic information, the 3D CAD model was structuralized and represented by using a feature attribute adjacency graph（FAAG）. Then, a multilevel feature descriptor capturing different levels of information for detailed part design was designed to establish the design feature similarity assessment model. Finally, the matched feature pairs were extracted by using the sub-graph isomorphism algorithm between the FAAGs of the query subpart and the part in the model library to calculate the similarity between matched subparts. Experimental results showed that the proposed method can effectively support subpart retrieval of 3D CAD models merging with design semantics for design reuse. The proposed research results can provide a novel reuse method of multi-granularity, precise and intelligent for the agricultural machinery digital design, and had an important role in improving the mechanical design efficiency and quality in the agricultural equipment field.