Abstract:Fruit branch clamping used in robot harvesting has advantages of universal use and little damage on fruit, but the clamping stability and reasonable clamping force are the bottlenecks of finger design. Firstly, the novel humanoid fingers were elaborated and the clamping force closure was analyzed. Clip-model in the condition of disturbance was developed, and a new clamping force calculation method was deduced. Secondly, the branch clamping test was operated on press machine. The relationships among clamping force, branch diameter, and maximum snatch force were built, and the quantitative description was also established. Finally, tests were performed to verify the clamp reliability by harvesting robot in the field. Results showed that the novel humanoid fingers can realize stable clamping on different sizes of branches and have little damage on them. The clamping force model was valid. The stable clamping can be achieved with disturbance. The success rate was 100% when clamping force was 15N.This will provide some theory evidences for harvesting method and universal fruit picking manipulator.

Abstract:Through the analysis of noise, it’s found that the Gaussian noise is the main noise in the night vision images obtained under different artificial lights, which also mixed with some salt and pepper noises. With regard of the elimination of Gaussian noise, the wavelet transform (WT) and independent component analysis (ICA) were introduced into the process of night vision images. In order to minimize the noise, a combined method of WT and ICA (WT-ICA) was proposed. The simulation results verified the effect of this combined method. For the purpose of better evaluation of denosing effect in these night vision images, taking the image under the natural light as a reference, an index named relative peak signaltonoise ratio (RPSNR) was proposed. The repeated tests were carried out in different night vision images. The results showed that there was an obviously visual decrease of noise with WT-ICA method. The RPSNRs of WT-ICA images were improved by 29.94%, 8.09% and 7.54% than those of original images, wavelet soft threshold denoising images and ICA denoising images. Especially under the incandescent lamp, the RPSNR reached the highest value, so this kind of lamp was suitable for being artificial light. By means of continued processing with WT-ICA method, these low noise images were easy to be identified further, which laid a solid foundation for the roundtheclock operation of the apple harvesting robot.

Abstract:To solve the problems of the slow convergence speed in ant colony algorithm and the local optimum in artificial potential field method, an improved ant colony optimization algorithm was proposed for path planning of mobile robot in the environment expressed by the grid method. The local force factor of artificial potential field was converted into spreading pheromones in the ant searching process, so the ant colony algorithm focused on subspace search with high fitness. It reduced the partial cross paths and the number of lost ants in the process of general ant colony algorithm in blind search. It also enhanced the ability of robot to avoid obstacle in advance. Two algorithms simulation results under different parameter combinations showed that the improved ant colony algorithm not only solved the local optimum problem of artificial potential method, but also avoided the blind search of general ant colony algorithm. In addition, the simulation results were compared with other improved algorithms. The comparisons verified the efficiency of the proposed algorithm which shows better search performance and stronger searching ability than the traditional ant colony algorithms and other improved algorithms. The convergence speed of the proposed algorithm was nearly doubled.

Abstract:To achieve precision mosaic of sprinkling width in wide spraying mechanism, a novel auxiliary GPS navigation method based on machine vision was put forward. Firstly, the foams sprayed to the breadths of spraying mechanism were identified, during which blue foams were chosen in order to effectively segment the target and background, and then the center line of foams image was obtained by iterative least square method after extrablue gray algorithm, morphological filter, anchor points selection and Otsu segmentation. Secondly, the definition of rotate angle and offset distance was given, and the information of course deviation was obtained by analyzing the parameter of foam’s center line. Experiments showed that the proposed method could accurately obtain the information of foams. The mean error of rotate angle between the values obtained by the proposed method and the real values was 1.58°, and the maximum value was 2.5°. The mean error of offset distance between the values obtained by the proposed method and the real values was 5.4cm, and the maximum value was 8.4cm.

Abstract:Due to the randomness and unpredictability of Ochotona curzoniae movement, the motions of Ochotona curzoniae contain smooth motions and abrupt motions in natural habitat environment. Under the circumstance of abrupt motions, the target position displacement is large between two adjacent frames. The stability and accuracy of the tracking method based on smooth motion hypothesis are difficult to guarantee. And abrupt motions are easy to cause Ochotona curzoniae tracking failure because abrupt motions violate the motion smoothness constraint. In allusion to the tracking problem of Ochotona curzoniae that smooth motions and abrupt motions coexistence, an Ochotona curzoniae tracking method based on the guidance of motion information was proposed. Considering the prior knowledge that the position displacement between two adjacent frames is smaller in smooth movement and the position displacement between two adjacent frames is larger in abrupt motion, motion information between the adjacent frames was extracted by the frame difference method at first and then the movement mode of Ochotona curzoniae was judged by motion information and appropriate sampling tracking strategy was taken to track Ochotona curzoniae. If the mode was judged to be a smooth motion mode, the Markov Chain Monte Carlo （MCMC） sampling tracking method based on the motion smoothness assumption was employed. Or else Wang-Landau Monte Carlo (WLMC) sampling tracking method used for abrupt motion tracking was adopted. The experimental results show that the proposed method can not only ensure the Ochotona curzoniae tracking performance of abrupt motions but also improve the Ochotona curzoniae tracking performance of smooth motions. The tracking success rate of proposed method was 95.49%, but the tracking success rate of WLMC method was 93.68%, the mean value and the variance of central point error in the proposed method were 13.46 and 67.89, which were 84.18% and 40.67% of those in the WLMC method, reduced by 15.82% and 59.33%, respectively.

Abstract:Aiming at the problems of low efficiency of artificial operation and serious pollution during the propagation of potato tissue culture seedlings, a shear mechanism for potato tissue culture seedlings with the whole bottle transplantation was designed. The proposed mechanism can make the potato tissue culture seedlings in whole bottle which were taken from the picking seedling machinery gather, shear and import dispersion in the sub culture bottle, then get into the next generation of rapid propagation culture, and finally realize the mechanized operation of gathering seedlings and cutting seedlings process with low pollution, high efficiency and high quality. The key structural parameters of claws, cutting knife and collecting seedling funnel were determined through analysis and calculation. Taking gathering seedlings speed and cutting seedlings speed as experimental factors, the single factor experiments for analyzing the effects of gathering seedlings and cutting seedlings were carried out. The optimal gathering seedlings speed and cutting seedlings speed were determined as 3.16rad/s and 10.26rad/s, respectively. A verified test of the designed shear mechanism with the above optimal parameters was conducted. The test results showed that the qualified rate of gathering seedlings was 99.13%, the damage rate of gathering seedlings was 0.79%, the success rate of cutting seedlings was 100%, the loss rate of cutting seedlings was 1.37%, and the success rate of collecting seedlings was 97.53%. Time for completing the process of potato tissue culture seedlings in whole bottle was only 48.67s and all the test indexes met the design requirements. The designed mechanism can provide a reference for the research of potato rapid propagation robot.

Abstract:Highquality seeds can increase the germination rate. Directional seeding can make corn blades grow regularly and enhance ventilation and light energy utilization in the field. These two are necessary conditions to achieve directional and precision seeding for corn seeds. This paper provided a device and an image detection algorithm of corn seeds for directional and precision seeding. Those unqualified corn seeds were found from the corn seed samples and the corn embryo direction of the rest qualified seeds were determined using this detection algorithm. The corn seeds were transferred in two lines by conveyors. Two cameras at different locations captured the transferred corn seeds at the rate of 50 frames per second. The same seed in continuous images needed to be detected only once. So the repeated corn seed images were judged and not detected. The seed region and outer contour were detected. The shape characteristic parameters, such as the area of the seed region and the perimeter of the outer contour, were calculated. According to the color of the embryo of the corn seed as close to white and the endosperm was close to yellow, the furthest point of the white part from the yellow area center was determined as the tip point of the corn seed. The axis through the tip point and the centroid point was defined as the major axis. The axis through the centroid and perpendicular to the major axis was defined as the minor axis. The angle α between the major axis and the horizontal direction was calculated. And on this basis, the shape characteristic parameters such as the length of major axis, the length of minor axis, the lengthwidth ratio, the degree of symmetry and the duty ration, were calculated quickly. The 100 qualified corn seed samples were randomly selected as standard seeds. The above shape characteristic parameters were detected successively. A qualified range was determined according to the standard seeds detection result. The unqualified corn seeds with such shortcomings as asymmetric shape, small size, round shape, severe wormeaten and serious damage were found and excluded. The corn seed color image was transformed into saturation binary image. If the target area of this binary image was far below the average area value of the standard corn seeds, the seed was considered with severe mildew. Slight black mildew was judged according to the value of （R+G+B）/3 was small. Slight white mildew or slight damage was judged according to the value of B-R was small. At last, the orientation of embryo, up or down, was detected according to the characteristics which the embryo of corn seed was close to white and it mainly located in the major axis. Of course, the direction of the tip point, left or right, determined the angle of α. Experiments show that this algorithm can detect the qualification and the direction of corn seeds quickly. The time of detection for one seed is about 14ms. The accuracy rate of repeated corn seed detection is 95%. The accuracy rate of qualification detection is 96.1%. The accuracy rate of embryo orientation detection is 97.1%.

Abstract:At present, the phenomenon of the redseed (the maturity of cottonseed is low) exists in the cottonseed processing. Most of the domestic cottonseed processing companies are still reliant on artificial monitoring for picking the redseed. However, the visual inspection of worker has some problems such as low automation level, many subjective factors and high labor costs. Besides, the process of cottonseed delinting also results in a decreased cottonseed germination rate and other issues. To solve these problems, this paper presents a dual CCD (Charge coupled device) detection system of delinted cottonseeds color sorter which is different from the current separation technology. Through the analysis of some subsystems in the detection system, such as optical subsystem, image acquisition subsystem and image processing subsystem, and also combined with simulation analysis and tests, the effects of the proposed system were verified. Wherein the image acquisition subsystem, the cottonseed maturity information was collected with the color linear CCD, and the integrity information was collected with black and white linear CCD. The key feature information which extracted by image processing and analysis was used to make type discriminant analysis of cottonseeds. The results showed that the detection system designed optical subsystem modules could obtain the imaged with clear features. The image processing subsystem could collect material feature information which could be used in image acquisition subsystem. The designed system could ensure the realtime and stability while sorting.

Abstract:The accurate location information of crop and grass provides the basis for intelligent intrarow weeding robot and influences the effects of weeding directly. This work describes the development of hoe-crop-positioning optimization system based on the fusion of machine vision and accurate odometry sensing techniques for intra-row weeding robot. The hoe-crop-positioning optimization system consists of two subsystems: machine vision system and information optimization system. The machine vision system is able to identify a single crop among weeds based on color camera. The information optimization system is able to calculate the accurate distance from crop seedling to weeding actuator. The optimization principle was analyzed. C8051F020 microcomputer was used as the core processor of hoe-crop-positioning system. In order to improve the accuracy of velocity measurement and anti-vibration interference, an accurate odometry collecting logical circuit was designed for frequency multiplication, phase demodulation and the other logic processing of the speed pulses. A double threshold optimization algorithm was used to judge the weights of real-time odometry data and forward distance from vision system, and to predict the discrete forward displacement of the machine in time. System assessment experiment was carried out based on a mobile hydraulic power pack platform. The experiment results show that the hoe-crop-positioning optimization system can effectively filter the error and instability information of machine vision. Under the static experiment the croppositioning error was 6.7mm, 10.3% less than that in earlier time. The weeding simulation experiment showed that the system can reduce the possibility of redundant rotation of hoe and improve the stability of weeding system.

Abstract:In order to meet the requirements of precision planting, pickup finger precision seed metering device was designed, which can perform operations of seed clamping, seed vibration cleaning and seed flexible guiding. The optimal designs of structural parameters in key components, such as the pickup finger, the vibration cleaning area, and the zero speed guiding belt, were conducted based on the analysis of working principle. To improve the working performance of the metering device and obtain the best operation parameters, the quadratic general rotary unitized design was carried out with the rotational speed of seed meter and the wire diameter of spring as the experiment factors and the seeding qualified index, the relaying seed qualified index and the missing seed qualified index as the experimental indexes. Based on experimental data, a mathematical model was built by using the Design-Expert 6.0.10 software, the experimental factors were optimized, and the best combination was achieved. Test results showed that when the spring’s wire diameter was 0.77mm and the rotational speeds were less than 19.2r/min, the seeding qualified index was 86.90%, the relaying seed qualified index was 9.62%, the missing seed qualified index was 3.51%, the improved metering device exceeded the original one by 13.5% in terms of the seeding qualified index, the damage rate of corn seed was 0.4%. On this basis, metering adaptability test was carried out which proved that the pickup finger seed precision metering device had good adaptability to corn of big flat dent, which met the requirements of precision seed sowing.

Abstract:A multilevel shuntmerge distributor was investigated for improving the adaptability of centrifugal precision metering device in the field, especially under some special conditions such as incline and jolt. Some factors those influenced the performance of valvebranch distributor were analyzed. After a quadratic orthogonal rotary regression simulation test by discrete element method software EDEM, a quaternionic quadratic regression model about apiece row consistency variability coefficient of seeding quantity was established. Meanwhile, the optimized distributor was manufactured by using 3D printer. Contrast experiment was conducted by using both direct distributor and branchvalve distributor under the inclined position. The results indicated that, when the branch length of first level shunt cell was 59.95mm, the top length of second level shunt cell was 66.11mm, the angle of shunt cell was 89.74°, the inner diameter of distributor was 7.12mm, and the seeding performance of the centrifugal metering device for rapeseed was very well. Concerning the range of 0° to 25° inclination, apiece row consistency variability coefficient of the device was no more than 5.71%, superior to the direct distributor, and it was also applied to the medium and highspeed planting, and satisfied the agricultural requirements of rapeseed planting.

Abstract:To further optimize the trajectory and pose of planting nozzle as well as the geometrical shape of hole digged out by planting nozzle, which could improve the seedling erectness rate of seedling transplanting, a combinational design of planting mechanism driven by twostage planetary noncircular gears was proposed. 25 different kinds of planting mechanisms were designed by using deformed ellipticconjugate noncircular gears, deformed eccentric circleconjugate noncircular gears, deformed Pascal curve noncircular gears, deformed Fourier curve noncircular gears and deformed sinusoidal noncircular gears. General mathematical model of planting mechanism driven by planetary noncircular gears was built, and the general model was substituted into the proposed multiobjective parameter optimization model of rotary seedling planting mechanism. According to conditions of planting agriculture, the types of planting mechanism and the corresponding parameters which met the perfect planting requirements were got by optimizing. One kind of planting mechanism driven by planetary eccentricelliptical gears was compared with planting mechanism with planetary deformed elliptic gears. The result showed that the planting mechanism designed by many kinds of noncircular gear pairs had better performance. According to the types of planting mechanism and the corresponding parameters which were got by optimization, structural design and prototype development were carried out, then the experiment of kinematics with highspeed camera and the experiment of simulating the field planting were carried out. The comparison between the trajectory, pose and speed of planting nozzle obtained from highspeed camera experiment and theoretical calculation showed that the structural design was reasonable, the machining precision met the requirements and the test bed can realize expected principle projects. The simulation experiment in field planting shows the planting mechanism has high seedling erectness rate of 95%.

Abstract:An intrarow brush weeding manipulator was designed for the crops with developed root system and compact soil condition. The manipulator is a part of intelligent weeding machine. Brush weeding with brush placed on a vertical rotating axis which is mounted on eccentric shank for avoiding crops is a new method for intrarow weeding. The principles of weeding and crop plants avoiding were studied. The mathematical model of device was established for kinematic analysis. In order to optimize the best structure parameter, the effect of three parameters (eccentricity of brush, diameter of brush, lateral offset) on crop row and trajectory of brush weeding device was analyzed based on Matlab. The results showed that 80mm eccentricity of brush and 20mm lateral offset which could acquire more than 80% coverage area of manipulator in the row were optimal parameters. Field trials showed that an average of 89.3% weeds could be removed and 3.5% crops were damaged when the transmission ratio of planetary gear was 3. Therefore, the intrarow weeding manipulator was able to meet the intrarow weeding requirements.

Abstract:As the center pivot irrigation system requires high fertigation uniformity, a kind of proportional fertilizing device was adopted in order to make the injection flux of fertilizer solution stable. A fertilizer injection device with plunger pump was designed. Based on the orifice size and installation location of injection check valve, and power frequency of plunger pump, field experiments on a center pivot irrigation system with fertilizer injection device were carried out to evaluate fertigation uniformity. The results indicated that when the center pivot irrigation system stopped and the plunger pump worked with power frequency of 50Hz, the Christiansen uniformity coefficient CU and variation coefficient CV of fertigation ranged from 99.00% to 99.65% and from 0.46% to 1.37% respectively under the combination of three orifice diameters and three installation locations. The maximum CU could be obtained by using the injection check valve with the orifice diameter of 2.5mm and the installation positioned at the horizontal inlet pipe. And when the center pivot irrigation system ran, the Heermann-Hein uniformity coefficient of fertigation C*UH with single line catchcans ranged from 88.77% to 90.66%, which indicated that the center pivot irrigation system can obtain high fertigation uniformity with the fertilizer injection device. In addition, the fertigation uniformity was compared with plunger pump working at power frequency and nonpower frequency of 46Hz. It was found that the average electrical conductivity of fertilizer solution had a significant positive correlation with the power frequency. Thus, changing the power frequency of plunger pump can provide an effective way to achieve high uniformity of variable rate fertigation for the center pivot irrigation system.

Abstract:To investigate flow field characteristics of jet mixing under variable working conditions, a jet flow field was analyzed with CFD simulation method and experimental analysis. The results indicated that the proposed numerical model could exactly predict the mixing ratio changed with outlet static pressure. It is showed that the mixing ratio decreased linearly with the increase of outlet static pressure. The static pressure distributions under different conditions demonstrated that the lowest pressure point along path ade located in mixing chamber was ahead of point d, and the static pressure decreased rapidly in nozzle field and rose up slowly in mixing tube. A local vortex appeared closed to jet core zone along path cd, which was affected by jet flow. The nondimensional performance curves presented a decreasing linear relationship between the pressure ratio and mixing ratio. The prediction error between numerical and experimental results was less than 6%; when the outlet static pressure was higher than 0.45MPa, the reflux status appeared in the jet mixing device which lost the function of waterpesticide mixing online.

Abstract:At present, some problems of rice straw returning machine still exist in China, such as shallow tillage depth, straw countersfield depth can not meet the agronomic requirements, and rotary parts are easy to winding straw, etc. A new kind of rice straw deep buried and whole straw returning device was designed by using the rotary tillage theory and numerical calculation analysis. With the hypothesis of soil particles based on the actual situation, the mechanical model of soil particles was established and the simulated virtual experiment of whole straw returning device was carried out by applying the discrete element method (EDEM). As a result, the coverage rate of topsoil reached 93.87% when the tilling depth was 20cm. By the soilbin bench tests, the following results were obtained: when the operation speed was 1.25km/h and the speed of knife roller was 237r/min, the tillage depth could reach 22cm; straws buried below the surface in 15~20cm accounted for about 80% of the total straw; the topsoil coverage rate was 91.63%; and the knife roller shaft would not wrap the straws. The test results showed that straw buried depth can meet the requirements of paddy field tillage link and the topsoil coverage rate was high. Through the mutual verification between virtual simulation and bench test, it is proved that the design of whole straw returning device could realize the functions of cutting soil, breaking soil, burying grass, pressing grass and covering soil, which meets the agricultural requirements well.

Abstract:The existing chestnut husker is not adapt to chestnuts just at the point of maturity, which is timeconsuming and inefficient, and even seriously restricts the development of chestnut industry. In order to overcome the chestnut husker with the shortage of high damage rate and low removal rate which are commonly used in the market presently, a chestnut husker was designed which can not only rub and peel the chestnut flexibly, but also screen the chestnut with reciprocating motion. The design of the key parts, including the bidirectional screening device part and the transmission system, was described in detail. The upper end of the bidirectional screening device was considered as the chestnut fruit export which was higher than the other end. The lengths of both the rubbing rubber plate and the rubbing arm can be adjusted to fit the chestnut thorn ball with different sizes. We produced more than 20 prototypes. The results of prototype experiment proved that the machine can meet the requirements of actual production. The tests for the chestnut thorn balls which are closed to maturity were conducted and the results proved that the threshing rate was more than 96%, the separating rate was more than 98%, and the loss rate was less than 4%.

Abstract:In view of the loss of maize cleaned out of maize harvester, models of maize mixture were founded by using EDEM software. Computational fluid dynamics and discrete element method (CFDDEM) were coupled to simulate the motion of maize in cross airandscreen cleaning device. The distribution of airflow and the trajectories and velocities of maize moving in the device were obtained, which reveal the work mechanism of the device. The results also showed that the debris of maize only included maize cob and main concentrated in the middle and at the rear of the device. And the performance of the device cleaning debris was enhanced with rises of inlet airflow velocities in the device, but the loss of maize was increased. The experimental results and simulation results consisted well. In order to meet the performance requirement of maize harvester, the loss rate of maize should be lower than 2%, the inlet velocity of airflow was ascertained and should be lower than 11.72m/s under the condition of the normal feed quantity of maize mixture of 3kg/s. Based on this, the rotating speed of the cross fan in maize harvester should be lower than 911r/min.

Abstract:Bill hook is a key part of Dbale knotter during load bearing. For the research on its mechanical analysis, baling experiment was carried out by using Huade 9YFQ-1.5 baler. The experimental scheme of tension sensor, high-speed camera and synchronous control was firstly proposed. The rope tension and acting position between rope and knotter during crop residue baling were obtained. The transfer model of rope around stump was built. The results showed that the largest loading between rope and bill hook was 314.89N. Based on the loading and acting position, the finite element mechanical analysis of bill hook was performed by ANSYS. The results showed that the stress concentration happened at the shaft end of bill hook and corner. The stress achieved to 755.52MPa and 410.29MPa, respectively. The observed broken position of bill hook during straw baling was also compared with the results from the finite element mechanical analysis. The results showed that the simulated data agreed well with the experimental data. This study will provide basic data for the optimization of bill hook.

Abstract:By establishing kinematical model of ropeholding motion, knotwinding motion, ropebiting motion of the knotter, timing sequence and position relation of ropeholding, successful knotwinding and accurate ropebiting were described analytically. The effects of the timing sequence difference value φ between the motion of knotting hook and the motion of ropeholding plate and the angle α between the knotting hook axis and principal axis on ropeholding motion, knotwinding motion, ropebiting motion were analyzed. After the ropeloosening, function of ropeholding motion was analyzed. The mechanic condition of firm ropeholding before ropebiting, as well as the mechanic condition of allowing the rope to slip along axle direction of ropeholding plate and avoiding breaking the rope after ropebiting were established respectively. The results showed that the rope could be held firmly, wound successfully and bitten accurately when the value of α and φ are 90° and 24° respectively. The motion test of the physical prototype validated the theoretical model accuracy of ropeholding motion, knotwinding motion and ropebiting motion. The results of knotting test without bundling straws and with bundling wheat straws showed that the knottied rate of knotter may reach 100% and 99.25% respectively, which proved that the motion parameters of the knotter were matched reasonably.

Abstract:The shape, diameter and fall velocity are the key physical characteristics of raindrops. Thus it is imperative that we begin to focus on the direction of physical characteristics of raindrops. In order to obtain physical properties of raindrops, light field and imaging system were designed based on the particle imaging transient visual measurement technology. The software for image identification, extraction and measurement were investigated, and a natural precipitation imaging measurement system based on a charge coupled device sensor was established. The result of the experiment on steel ball showed that the measurement technology had small relative error. By the field experiment, we found that mediumsized particles were the predominant contributor in the single rainfall, with the diameter of 2.00mm and average fall velocity of 3.52m/s. Mathematic model was developed to calibrate fall velocity and diameter by using linear regression, and the prediction accuracy and precision were reliable. In conclusion, characteristics of raindrops can be measured precisely by the proposed technology, which is a novel method for observing rainfall properties and further researching soil erosion.

Abstract:To solve the problem of moisture realtime detection in high salinealkali soil and high organic soil, this paper used time domain transmission (TDT) method to detect soil moisture based on phase detection. The probe of sensor structure and measuring frequency were analyzed in detail. The experiments showed that when the probes were 2mm in diameter, 10mm in interval, 120mm in length and the frequency was 100MHz, the measured performance was good to meet the demands of actual measurement. The measurement error of TDT soil moisture sensor in sandy loam, clay loam, salinealkali soil and high organic soil were ±0.87%, ±0.95%, ±2.20% and ±1.94% respectively, and the dynamic response time of TDT soil moisture sensor was about 4ms. The comparative analysis between foreign equipment TRIME (TDR) and domestic equipment BD-Ⅲ type soil moisture sensor showed that TDT soil moisture sensor of 100MHz could meet the requirements for detecting high salinealkali soil and high organic soil moisture in realtime. In addition, this device has good dynamic performance and stability with less technical difficulty and low cost but for good research and application prospects.

Abstract:The Phase Shift Micro XAM-3D was used to measure the roughness of smooth wall, new lateral wall and lateral wall attached by biofilm. The phaseDoppler particle anemometer was used to measure the particle movement with the effect of different walls. The study used three different particle sizes: 10μm, 50μm, 100μm under three different walls. The results showed that the surface area of biological lateral wall (212%) was significantly higher than that of new lateral wall (4.37%) and smooth wall (0.196%). The velocity of small particles (particle size of 10μm) collided with smooth wall was lower than that collided with the biofilm lateral wall. The velocity distribution of smooth wall, new lateral wall and biofilm lateral wall tended to be gradually wider and wider. While the average velocities of middle particles (50μm) and big particles (100μm) are closed to zero and didn’t widen. The reason is that the biofilm enhanced the surface adsorption capacity which reduced the number of small particles. The result proved that the effect of biofilm on big particles was not significant.

Abstract:The movements of tracer particles in labyrinth channel under dynamic and constant water pressure were observed based on partical track velocimetry (PTV) technique. Water flow characteristics in labyrinth channel were analyzed and the anticlogging mechanism of drip irrigation system under dynamic water pressure was discussed. The results show that when comparing with constant water pressure, flow rate in the channel under dynamic water pressure did not decrease significantly. Therefore, the effect of dynamic water pressure on water delivery capacity of drip irrigation system was not obvious. While the flow velocity in channel’s main flow path fluctuated dramatically under dynamic water pressure supply system, and the turbulence was more intensely. Most particles could pass the main flow path quickly and the residence time of tracer particles reduced significantly. The flow velocity in the flow stagnation zone was relatively low while the turbulence remained strong. So the particles can hardly deposit in the flow stagnation zone due to the remarkably fluctuation. Meanwhile, some particles in the flow stagnation zone returned to the main flow path and finally flew out of the channel, which lead to the significant decreasing possibility of particle deposition in the channel. Therefore, dynamic water pressure could improve the anticlogging performance of drip emitter effectively.

Abstract:Sand sampler is necessary for studying sand flow structure and sand movement law. In order to solve the effective separation problem inside sand sampler under the strong wind environment, this paper proposed a diversion gas hedging method. A shunt-hedging sand sampler was designed, and the design principle of diversion gas hedging method and parameters analysis for shunt-hedging sand sampler were described. The wind tunnel experiment and performance analysis on a wind-sand separator were carried out by Fluent software based on numerical simulation. The results showed that the proposed shunt-hedging sand sampler showed a high deceleration and antistrong winds performance. The deceleration magnitude of exhaustport was 88.44%, and the deceleration magnitude of desilting-port was 90%, which ensured the effective separation of wind-sand inside a sand sampler. The average sampling efficiency was 90.15%, and the equal dynamic performance was 93.27%, which was consistent with the basic requirements of designing a sand sampler. It also had low production cost, and could better satisfy the needs of wind tunnel experiments and erosion observation.

Abstract:The Naoli River Basin is the largest basin on Sanjiang Plain. Its runoff variation plays a crucial role in the development of social economy and ecological environment change of Sanjiang Plain. In order to obtain the variation characteristics of runoff series, the linear trend analysis and Mann-Kendall test were used to analyze the trend of runoff series of four representative hydrological stations in Naoli River Basin. Then the moving cut data-approximate entropy (MC-ApEn method) and Mann-Kendall mutation testing were used to check the mutation characteristics of runoff series. Also the mutation reason of the runoff series was discussed. The results showed that the runoff volume of Naoli River was distributed unevenly and the annual runoff of the same hydrological station had great variation. It was not conducive to the full use of water resources in Naoli River Basin. Runoff series showed obvious reducing trend in the recent 50 years, and the runoff of the Baoqing Station, the Baoan Station and the Caizuizi Station decreased obviously. The runoff mutations of Naoli River occurred in 1966, after the abrupt change, there is an obviously decreasing trend of runoff which is large because of reduced precipitation, increased urban residents water consumption and the growing number of construction of water conservancy. The moving cut data-approximate entropy in the process of runoff mutation analysis showed the characteristics of high precision, strong antiinterference ability and so on and it is a method for detecting the mutations of nonlinear time series.

Abstract:Henan Province is a main grain crops producing area in China, and water requirement trends of the main grain crops is an important basis for agriculture water saving and yield increasing. Based on the daily meteorological data from 18 stations in Henan Province during 1958 and 2013, reference crop evapotranspiration (ET0) and water requirement of winter wheat and summer maize in growth period were estimated by using FAO Penman-Monteith equation and crop coefficient. Time series analysis was used to analyze temporal distribution characteristics of ET0 and water requirement. Kriging of ArcGIS was introduced to draw the maps of ET0 and water requirement that could present a clear spatial distribution of that, and the causes of water requirement change were manifested by path analysis method. The research results showed that the value of ET0 in Henan Province ranged from 672mm to 977mm, and the average values were 807.0mm per year and 2.2mm per day, which was decreased in recent 62 years. The maximum ET0 appeared in the northwest and southeast of Henan Province, and ET0 showed a significant difference around the western area. The water requirement of winter wheat and summer maize were 390~562mm and 314~426mm, respectively. The irrigation requirement of winter wheat and summer maize were 350~525mm and 243~368mm, respectively. The index of irrigation requirement of winter wheat and summer maize were 0.77~0.90 and 0.66~0.83, respectively. The main grain crops irrigation requirement index of Henan Province tended to increase with the latitude and longitude, and summer maize had less dependence on irrigation than winter wheat. When each meteorological factor was removed respectively in sensitively analysis, the reliability of the regression equation was estimated by the remained eight meteorological factors. The main meteorological factors that influence water requirement of the main grain crops were temperature, vapor pressure, sunshine duration, maximum temperature and wind speed.

Abstract:After the hydrolysis acidification of vinegar fermentation wastewater, the cultivation of Chlorella sp. and nutrients removal in different concentration hydrolyzates of vinegar fermentation wastewater were investigated in the vertical tubular photobioreactor. Results showed that after the hydrolysis acidification of vinegar fermentation wastewater, the removal rates of COD, ammonia, volatile fatty acids (VFAs) and total phosphorus (TP) were all decreased to some extent. The removal rates of COD and TP were 61.8% and 63.6%, respectively. The components of VFAs were changed significantly. When the volume fraction of hydrolyzate was more than 40%, the growth rate of Chlorella sp. was inhibited. When the volume fraction of hydrolyzate was between 10% and 30%, the growth rate of Chlorella sp. was good. The concentration of Chlorella sp. cell could achieve 6.6×107cells/mL. The growth curves of Chlorella sp. were no lag phase, after the addition of phosphate in the hydrolyzate of vinegar fermentation wastewater. After 7d cultivation, the ammonia and total phosphorus were almost completely removed. The 96.6% COD removal was achieved after addition of some phosphate. The oil content (24%) was observed using 30% volume fraction hydrolyzate of vinegar fermentation wastewater. The contents of fatty acids C16-C18 were between 83.0% and 95.5%, which had good potential for the development for biodiesel utilization.

Abstract:The mix volatiles of biooil steam and noncondensable gases need to be separated by condenser in the consecutive apparatus. Relevant researches about water steam condensational effect with air or N2 were carried out by researchers both at home and abroad. It showed that non-condensable gases can distinctly affect condensational process by reducing local heat transfer coefficient. A system of condensational testing tube was built for pyrolysis volatiles at different temperatures. Volatiles of oiltea camellia produced at 400℃, 500℃ and 600℃ were tested in this system. As a result, local heat transfer coefficients decreased with the increase of condensational process. The values of volatiles at 400℃ were higher than those at 500℃ and 600℃, which showed that the increase of noncondensable gases decreased the heat transfer intensity of volatiles. When experimental data were simulated in Nusselt theoretical model and ffactor model, the result showed that compared with the Nusselt theoretical model, f factor model was more suitable for fitting experimental result of oiltea camellia volatiles produced at 500℃ with the error less than 20W/(m2·K). Exponential decay equations can fit the experimental data of volatiles at 400℃ and 500℃, which brought an assistant reference for biooil condenser design in consecutive pyrolysis apparatus.

Abstract:Ammonia stripping process consumes large amounts of alkali. The packed column is easy to scale and cause pressure drop. The tray tower has the disadvantages of discharge and the large fine droplets loss by entrainment. Besides, the absorption of ammonia nitrogen in the exhaust gas is incomplete. In order to solve the above problems, a twostage airrecirculated stripping process was developed and used in the gasliquid reactor to remove the ammonia nitrogen during anaerobic digestion of pig manure. A mathematical model focusing on the effects of controlling factors (gas flow rate, dose of alkali and gastoliquid ratio) on one response (ammonium nitrogen removal efficiency) was developed and fitted by response surface methodology (RSM). The results showed that the pH value could rise from 803 to 886 in 1h by stripping CO2. The alkalinity of anaerobic digestion was decreased from (8.953±297)mg/L to (8.283±21)mg/L. Stripping carbon dioxide was conducive to reduce the buffer capacity of anaerobic. The ammonium nitrogen removal efficiency could reach 96.78% (dose of lime 22.13g, gas flow rate 6L/min, gastoliquid ratio 3.000). The twostage airrecirculation process could be used to remove and recover ammonium nitrogen in anaerobic digestion of pig manure without pretreatment in this system. The RSM further optimized the twostage airrecirculation ammonia removal process. The developed gasliquid reactor could be used to remove ammonium nitrogen with airrecirculated stripping process.

Abstract:Solid state fermentation is a distinctive technology for vinegarmaking. In general, the vinegar quality was evaluated by the contents of nonvolatile acid and total acid. The relationships between the contents of alcohol dehydrogenase (ADH) activity from 56 different fermentation seed tanks and the contents of nonvolatile acid and total acid from 56 different vaccination fermentation tanks were analyzed. The result showed that, when ADH activity values were controlled in 600~700U/mL, the vinegar substrate would showa good performance in quality. Whats more, the olfactory visualization sensor combined with backpropagation artificial neural network (BP-ANN) was used to test the ADH activity and predict nonvolatile acid and total acid. The result showed that the value of correlation coefficient of ADH activity, nonvolatile acid and total acid were 0.7816, 0.8447 and 0.9463, respectively. Therefore, the olfactory visualization sensor combined with BP-ANN could be well used in the prediction of physicochemical index for vinegar substrate.

Abstract:A realtime detection and processing system for contaminants on chicken carcass surface was designed based on machine vision technology. The surface feature images in the wavelengths 500nm and 710nm of chicken carcass were acquired by means of industrial camera, filter and computer respectively. These images were firstly processed with the median filtering and gray enhancement. Then the binarized images were obtained by using Otsu automatic thresholding. Then, the corrosion, expansion and void filling operations were conducted on these images, and the contamination areas on chicken carcass surface were segmented. On the basis of this, if contaminations (cecal fecal, blood, bile) on the surface of chicken carcass were distinguished, the spray treatments for these contaminations were carried out. The experimental results showed that the total average correct ratio was 90.5% when this system was used to detect three contaminations on the surface of chicken carcass, implying that this system could be used for online detection of contaminants on chicken carcass surface with high detection accuracy and reliability.

Abstract:To explore the potential of dielectric spectra in predicting internal qualities of pears, the dielectric constants and loss factors were measured by using openended coaxialline probe technology at 201 discrete frequencies from 20MHz to 4500MHz on 310 pears, picked from four different orchards, during 8week storage. Soluble solids content, firmness, and moisture content were considered as internal qualities. Sample set partitioning based on joint x-y distances was used to subset partitioning, and 233 samples were used in calibration set and 77 samples were used in prediction set. To simply establish model, successive projection algorithm method was applied to extract characteristic variables (CVs), and 15, 14 and 15 CVs were extracted for soluble solids content, firmness and moisture content, respectively. The modeling methods, such as least square support vector machine (LSSVM), extreme learning machine (ELM) and back propagation (BP) network were used to establish soluble solids content, firmness and moisture content determination models based on full dielectric spectra and extracted CVs by SPA. The results showed that the LSSVM model based on full dielectric spectra had the best soluble solids content determination performance and good prediction ability, with the correlation coefficient of calibration set of 0.974 and prediction set of 0.931, the rootmeansquare error of calibration set of 0592°Brix and prediction set of 0.868°Brix, and the highest residual prediction deviation of 2.65. The LSSVM model based on SPA could be used to predict the moisture content roughly. However, all models had poor prediction ability on firmness. The study indicates that dielectric spectra combined with LSSVM could be used to predict soluble solids content and moisture content of pears, but it is difficult to predict firmness using dielectric spectra. The study provides a method for nondestructive determination of soluble solids content and moisture content of pears.

Abstract:Wettype microwave sterilization is a newly developed technology. A 3D unsteady active heating mathematical model of hot water and microwave sterilization in a single mode system at the frequency of 2450MHz was established based on the coupled equations of electromagnetic heating and heat transfer. The distribution of electromagnetic field in microwave cavity and heating pattern in food sample were obtained by using finite element method and the good results were used to guide the design of microwave sterilization equipment. It was determined that the optimum size of pyramidal horn was 283.92mm×136.50mm×109.20mm and the height of cavity was 75mm. A twocavity microwave sterilization system was developed. Experimental results demonstrated the temperature of package food rose from 50℃ to 142℃ in just 2min. Furthermore, it showed that the heating pattern in food was stable and the temperature distribution was more uniform owing to water circulation which reduced the edge overheating effect. In addition, this study confirmed that it not only effectively met the requirements of pasteurization process but also verified the effectiveness and rationality of the designed device.

Abstract:Quality grading is usually performed to agricultural products after harvesting by sorting machines with existing problems including large size, high price, etc. To meet the demands of family farming and small scale marketing, we designed a small-scale agricultural product sorting machine based on machine vision. Agricultural products were conveyed to the multichannel conveyer belt and sorted with features including shape, color and etc. by the DSPcored machine. Quality of products in separated channels can be analyzed with single frame image. Performance tests were conducted with walnuts, red dates and chestnuts selected as testing objects to the sorting machine. The test parameters including horizontal transmission speed, product transmission interval, parallel transmission channel amount were set to 9.2cm/s, 16cm and 4, respectively. The test results indicated that the sorting machine performed reliably with selection accuracy rate of 91.66%, 94.79% and 97.39% in walnuts, red dates and chestnuts respectively, with culling speed of approximately 8800 products per hour. Hence feasibility was proved that DSP could be performed as the machine vision core component of smallscale intelligent sorting machine, which provided technical supports of miniaturization and low cost for agricultural product sorting machines.

Abstract:Postmortem aging is an important method for improving meat quality. In order to provide theoretical basis for improving meat quality, the experiment was conducted to determine the termination of postmortem aging for yak meat by measuring pH value, and to investigate the differential proteomics between fresh and postmortem aging yak meat. The Longissimus dorsi from Qinghai Datong yak was used to determine proteomic by ultracentrifuge and twodimensional electrophoresis. Imagine analysis for selection of differentiallyexpressed protein spots was conducted by PDQuest 8.0 software. Proteins were identified by ion trap mass spectrometry equipped with surveyor HPLC system. The results showed that fiftyfour spots from electrophoresis gels were selected as differentiallyexpressed proteins for MS analysis, and eighteen proteins were identified, in which forteen proteins showed downregulated expression, one protein only expressed in fresh meat and three proteins only expressed in postmortem aging meat. These differentiallyexpressed proteins separated in this study involved metabolic, structural, and stress related proteins. The research proved that metabolic, structural, and stress related proteins had varied abundance during postmortem aging in Longissimus dorsi of Qinghai Datong yak. In summary, the study contributes to clarify the mechanism involved in the aging process of yak meat.

Abstract:This paper reviewed the development history of the forest survey equipment and technology of domestic outside, summarized the current use of forest survey equipment and related technology, and concluded the development trend of equipment and technology which have been gradually developed to the intelligence, refinement and precision. Through the synergy of integration of aerial-space-ground, the developed equipment and technology enhanced the precision and accuracy of forest survey, improved the work efficiency of forest survey, reduced the waste of a lot of manpower and material resources, and built the forestry information platform at the same time. The platform was based on Internet and GIS technology, and it was built through the combination of software and hardware. The software mainly included traverse survey, coordinate sample, area calculation, volume calculation, single tree volume, section area per hectare determined, stand volume, statistical graph, statistical table, and forestry mapping etc., whats more, the information platform realized the application system with comprehensive functions of survey statistics, basic figure, stock map, forest distribution map and thematic map. In particular, the construction of forestry information platform promoted integration and intelligence of forestry resources survey. Forest survey system of aerial-space-ground was an inheritance and development of the existing equipment and technology. Therefore, the forest survey equipment enters into a new era featuring close relation with geographical information system technology, photogrammetry technology, remote sensing technology, information technology, space technology, image technology and graphics technology.

Abstract:The measurement of tree diameter at breast height (DBH) is an important parameter for evaluating site quality and tree growth status. An ordinary digital camera was used to randomly shoot plot that was measured in an up and down direction. And the length of object should be measured so as to reversely deduct the position of photographic baseline and recovery the true spatial scale of photography area, achieving the aim for measuring the DBH of sample trees in the plot and the coordinate of the trees center. This research was based on theory of photogrammetry and carried out with the coplane of rays from same point and photographic as the conditions. Aiming at the limitation of photogrammetry, this research established the photogrammetry mode mainly in a vertical ground direction. The validity of the proposed algorithm was analyzed and verified in the experiment. Software of ground stereo photogrammetry system was developed, taking Microsoft Visual Studio as development platform. Twentyfive standing trees in five plots were measured and calculated. Experiment results demonstrated that the precision of DBH measurement using ordinary digital camera was high, and the experimental data were in good agreement with the actual, with the average absolute error of 0.29cm, and the average relative error of 1.99%, which were in line with the tree diameter at breast height measurement accuracy of national forest resource continuous investigation. With the constant increase of field working cost, people will pay more attention on the utilization of portable instruments in measurement. Therefore, the method has practical application prospect in forest resource survey.

Abstract:Region were applied to simulate the satellite spectral reflectance of domestic highresolution satellite GF-1,〖JP〗 and then eighteen broad vegetation indices which were sensitive to the chlorophyll content were obtained based on the simulation reflectance. The relationships between SPAD values and eighteen vegetation indices were analyzed at different growth stages of winter wheat, and the most related vegetation indices were selected to construct the remote sensing monitoring model of SPAD value for leaf by regression analysis. Finally, the models for wheat greenup stage were used to estimate the SPAD value for winter wheat leaf through GF-1 satellite data. The results showed that the SPAD values were highly related with the TGI index in greenup, booting and whole growth periods. The correlation coefficients were -0.742, -0.740 and -0.483, respectively. The SPAD values were significantly related with SIPI and GNDVI indices in jointing and grain filling stage, and the correlation coefficients reached to 0.788 and 0.745, respectively. The GNDVI, GRVI and TGI indices kept a good relationship with leaf SPAD values in each growth period at the 0.01 probability level. All the regression models proposed by GNDVI, GRVI and TGI indices performed well, especially the RandomForest regression model (SPAD-RFR). The best prediction results appeared at the jointing stage of winter wheat. It concluded that SPAD-RFR regression model based on the GF-1 satellite imagery data could effectively monitor the SPAD value for winter wheat leaf in the study area.

Abstract:he objective of this study is to build soil water supplement model. The characteristic of the model is the couple of the daily average transpiration coefficient and the subsection ratio of leaf transpiration and soil evaporation, while the coefficient and the ratio are often assigned to constant values during crop growth and development period in past studies. The model is used to quantitatively calculate the amount of evapotranspiration and soil water supplement during the whole growth period of winter wheat of Guanzhong Plain during 2007—2008 by using the remotely sensed and dynamically simulated LAI and biomass. The pointbased verification show that the results are accuracy when fully access to the information of rainfall and irrigation conditions. According to the spatial distribution of the soil water supplement, the soil water supplement in the whole growth period of winter wheat gradually decrease from the northwest to the southeast in Guanzhong Plain, which is roughly consistent with the variation trend of the water stress level in study area. In addition, the soil water supplement calculated by model in 2000—2001 reveal the possibility to obtain a more accurate result if we can get more high quality remotely sensed data, especially which are during the main growth period of winter wheat. All the results confirm that the feasibility of using this model to retrieve the soil water supplement throughout the growth period of winter wheat.

Abstract:Landsat 8 remote sensingimages possess higher spatial resolution and higher temporal resolution.The timeseries Landsat 8-NDVI metrics could reflect the phenology calendar, planting pattern, planting structure and planting area information due to its high spatial resolution and high temporal resolution, thus it is an ideal data source for accurate extraction of maize planting area. In most extraction methods, the decision tree classification method is considered to be rapid and efficient, which could extract maize planting area using multithreshold. However, because of the mixedpixel, both the larger and smaller threshold will lead to errors. This problem could be resolved by mixedpixel unmixing method using endmember abundance calculation to eliminate the disturbance of heterogeneous classes. Therefore, taking timeseries Landsat 8-NDVI metrics as data source and using the combined method of decision tree and mixedpixel unmixing methods are effective way to extract crop planting area. The maize planting area in Hebei Province was extracted in this paper based ontimeseries Landsat 8-NDVI. Firstly, the features of timeseries Landsat 8-NDVI curves were analyzed and the decision tree was built to get the distribution of early sowing maize, interplanted summer maize and spring maize. Secondly, mixedness decomposition was calculated among three kinds of maize based on mean NDVI spectral curve of endmember, so maize planting area could be extracted accurately by using computed maize endmember abundance. The accuracy assessment results indicated that the overall classification accuracy of maize planting area was higher than 98% and Kappa coefficient was higher than 0.97. Generally speaking, the main planting crop was summer maize, and spring maize was mostly planted in the south part of Zhuozhou City. These results were accordant with field work data. The above quantitative and qualitative accuracy assessment results indicated that this method can be used to extract maize planted area quickly and accurately.

Abstract:The development of precision agriculture demands high accuracy and efficiency of cultivated land information extraction. Due to the low spatial resolution of satellite remote sensing images, it is difficult to identify cultivated land of small areal extent in critical regions; this requires image data of high spatial resolution for specific or general cases. Simultaneously, unmanned aerial vehicle (UAV) has been increasingly used for natural resource applications in recent years as a result of its greater availability, the miniaturization of sensors, and the ability to deploy UAV relatively quickly and repeatedly at low altitudes. In order to solve the problem of large quantity, distortion and accumulated error in the process of UAV image mosaic, how to reduce accumulated error efficiently was researched. First of all, matching area was calculated according to the record center points in process of matching. Then error equation was listed based on the results of regional network summary calculation. Next, images were given weight value by different terrain features areas to conduct area weighted adjustment. Finally, mosaic experiments were completed by the proposed method and direct mosaic method based on three flight strips UAV images. The experimental results show that the ghost and dislocation phenomenon was decreased by 12%, mosaic efficiency was increased by 15%, and the area after mosaic was expanded by 8%. The method can mosaic UAV images better at error control and efficiency.

Abstract:To achieve the previsual detection on nitrogen(N) stress, the microelectrode technique was used to measure the membrane potential, membrane capacitance and light induced responses of leaf membrane potentials under four different levels of Ntreatment, respectively. No obvious difference was found in the membrane potential between Nstress and Nsufficient cucumber leave. It shows that the membrane potentials were not suitable for early diagnosis of Nstress in cucumber plants. The research on the changes of membrane capacitance found that it was sensitive to Ndeficiency. The measurement of membrane capacitance could be used for previsual diagnosis of severe and moderate Ndeficiency 2d before the appearance of visually morphological changes. The research on the changes of magnitude of leaf membrane potential response to light found that it was sensitive to Nexcess. The measurement of the magnitude of leaf membrane potential response to light could be used for previsual diagnosis of Nexcess at least 7d before the appearance of visually morphological changes. It shows that the microelectrode technique is suitable for early diagnosis of Nstress in cucumber plants.

Abstract:To provide farmers with vegetable diseases knowledge, this paper proposes a method based on voice recognition technology to label and split vegetable diseases videos. Through this method, videos about vegetable diseases can be split into several smaller segments which are more suitable for cell phone. The methods of semantic annotation and video shot clustering were based on video segmentation and voice recognition. In this method, the audio signals of videos were transformed into text strings firstly by voice recognition. Then key semantic entities for labelling video shots semantically were split from the text strings. Finally different video shots were clustered and recombined based on keywords provided by user and the semantic labels of video shots. When applying the method of semantic annotation to two videos, the recall ratios were up to 96.08% and 94.93%, the precision ratios were up to 94.31% and 95.98%, and the F-1 measures were up to 0.93 and 0.92. As for method of video shot clustering, the recall ratios were up to 94.9% and 98.7%, and the precision ratios were up to 92.1% and 90.2%. Results of comparative experiments show that the proposed method is valuable both in theory and practice.

Abstract:In order to convert the weak fluorescence signals in the optical path of water optical sensor for chlorophyll a to stable electrical signals and meet the input requirements of analogtodigital conversion device, based on the early research on designing the optical path, this paper designed a signal processing circuit in optical intelligent sensor for the chlorophyll a of water. This circuit has four parts, including the excitation light source driver module, the photoelectric I/V switching and amplifier module, the filtration module and the demodulation module. For excitation light source driver module, we used the integrated driver chip which has the advantages of high bias compatibility, minimum bias and migration and lower dropout voltage to drive multiple LED at the same time. Compared with the traditional current limiting resistor project, the proposed project was more stable, highly effective and more consistent with the driven current. The photoelectric I/V switching and amplifier module which was passed through twostage amplifier called I/V conversion circuit and the same proportion amplifier circuit respectively, could amplify AC and inhibit DC compared with the traditional filter and amplification circuit. In filtration module, we used the monolithic integrated active filter without external capacitance. Compared with the traditional highorder lowpass filter, the stray capacitance’s influence was small, and the circuit size can be effectively reduced. In demodulation module, we used an integrated converter chip with incremental accumulating conversion method. Compared with the traditional peak detection circuit, the output amplitude of railrail output was wider, the conversion speed was faster and the conversion accuracy was higher (99.75%). It also had more stable output direct current and smaller temperature drift.

Abstract:The anthocyanin content in leaves can provide valuable information about the physiological conditions of plants and their responses to stress. Thus, there is a need for accurate, efficient and practical methodologies to estimate the biochemical parameters of vegetation. In this study, the peony leaves of different varieties in the early flowering stage were selected as the research objects to analyze the correlation between anthocyanin content in leaves and reflectance spectra. The predictive models were established based on a single band or different vegetation indices. The PLSR(Partial least squares regression) model was constructed to estimate anthocyanin content in leaves by using the reflectance spectra with correlation coefficient more than 0.52 in visible band as independent variables. The results showed that the maximum correlation coefficient between reflectance spectra and anthocyanin content was located at 544nm. These predictive models which used the reflectance at 544nm, ARI (Anthocyanin reflectance index) or MARI (Modified anthocyanin reflectance index) as independent variables could be used to estimate anthocyanin content in peony leaves in fact. The calibration and validation R2 of optimum model for predicting anthocyanin content in poeny leaves established by PLSR were 0.873 and 0.811, and the RMSE and RPD were 0.068μmol/g and 2.352, respectively. This study can provide a method for nondestructive estimation of anthocyanin content in plant leaves, and make a reference for the assessment of physiological status of plants and early stress detection.

Abstract:Field data collection, comparing with other data acquisition methods such as remote sensing or wireless sensor network, has advantages of high flexibility, high accuracy and gradually becoming one of the main methods for complementing agricultural data.We analyzed the actual demands of crop planting environment data collection work, and on that basis, presented an Android based crop planting environment data collecting system prototype (CPEDCS). Firstly, in consideration of uncertainty characteristics of crop planting environment indicators, we designed a customizable data input mode based on structural data table, which supports users to set indicators by editing XML file, defines visibility and arrangement of indicators, and configures default value of each indicator; secondly, mobile GIS module was integrated in CPEDCS client to provide spatial information, and the module can automatically adapt to variation of data type, file quantity and spatial range; thirdly, we realized efficient image data management and application by image data acquisition, compression, coding and transmission, and users can query image data in different sample points realtime through browser. At last, we applied our system on crop planting environment data collection work in Yangling District, Shanxi Province in April, 2013 and April, 2014. The experimental results show that the CPEDCS has high practicability and stability, and to some extent could increase data collecting efficiency, reduce error rate on data input, and provide spatial information for investigators.

Abstract:To improve the dynamic performance of a V-type diesel engine at high altitude, the matching calculation was carried out between the diesel engine and regulated two-stage turbocharging system, and the two-stage turbines and compressors were determined. The calibration results of optimum valve opening and optimum boost pressure were achieved at all operating conditions according to the steady performance target at different altitudes. The transient simulation model was constructed, and the effect of different altitudes on the transient response characteristic of boost pressure was investigated. The openloop and closedloop control strategies were designed based on the MAP diagram of optimum boost pressure to improve the transient response of boost pressure at different altitudes. The results showed that the closedloop control strategy can achieve better transient response compared with the openloop control strategy. With the closedloop control strategy of boost pressure, the response time was reduced from 2.82s to 2.41s at the altitude of 0m. The response time was reduced from 3.20s to 2.32s at the altitude of 3000m, and it was reduced from 3.41s to 2.25s at the altitude of 4500m. The effect of different altitudes on transient response characteristic was largely weakened with the closedloop control strategy. 

Abstract:The helical intake port geometry directly controls swirl ratio, volumetric efficiency and combustion characteristics as well as emissions reduction of diesel engine. A new digital design method of helical intake port was studied. In this method, cylinder head structure was considered as a constraint condition, and the swirl ratio was considered as the design target; then the flow coefficient was optimized. The effect of the geometry structure and port sensitive areas of diesel engine helical intake port on the intake port flow characteristics was analyzed, and several key structural parameters of helical intake port were defined. As a result, a parameterized mathematical model of helical intake port was established. Based on parameterized mathematical model of helical intake port and several key structural parameters of helical intake port, a digital modeling software about diesel engine helical intake port was developed. For the design requirements of helical intake port of selfdeveloped horizontal twocylinder diesel engine, a digital 3D model of helical intake port was established by using the helical intake port digital modeling software, and model smoothness and flow characteristics of this 3D model were analyzed. The results show that helical intake port digital design method has a certain feasibility and versatility. Just providing with the design requirements of the cylinder head structure and flow characteristics (swirl ratio and flow coefficient), a helical intake port that meets the requirements can be designed through using the digital design method and modeling software.

Abstract:EGR (Exhaust gas recirculation) stratification is a promising solution proposed to control incylinder distribution to decrease NOx and PM (Particular matter) generation during combustion process. The key issue of EGR stratification is to control incylinder distribution. A novel method called timing sequential intake strategy which divides the intake process into several periods and controls different intake charge flows into engine cylinder for each period was proposed and investigated by computation fluid dynamics (CFD) technology. The simulation model was established based on a heavy duty diesel engine. It is indicated that intake charge in earlier intake period was rich at the bottom of combustion chamber while the later charge was rich at the upper center of combustion chamber near compression top dead center. It is feasible to obtain axial stratification using timing sequential intake strategy. The combustion pressure and temperature were lower than those of uniform intake strategy which supplying the mixture of intake CO2 and fresh air during the whole intake process. Compared to the uniform intake strategy, the start of combustion delayed about 0.7°CA, however, the peak value of heat release rate was much higher, NOx emissions were decreased by 51.2%, and PM emission was decreased by 13.4%. Timing sequential intake strategy needs to be further investigated as it is beneficial for both reductions of NOx and PM emissions and fuel consumption.

Abstract:To deal with the problem of obstacle avoidance for redundant dualarm robot, an obstacle avoidance algorithm based on selfmotion was presented. In order to fully describe a cooperative task for a dualarm robot system, this allows a straightforward description of general coordinated motion in terms of meaningful absolute and relative variables. The proposed Jacobians were expressed in terms of the Jacobians of the single manipulators. Based on this, the kinematics inverse solution of redundant dualarm robot used to avoid obstacles was obtained. Using this approach, the robot can accomplish the coordinated motion tasks while avoiding the obstacles. Finally, the validity of the algorithm was manifested by simulation of a redundant dualarm robot. Results show that the closest distance between the manipulator and the obstacle was more than 0.015m, while the endeffector of the robot can accomplish the coordinated motion tasks accurately and the path was smooth. As a conclusion, the redundant robot can not only realize the obstacle avoidance, but also accomplish the coordinated motion using the proposed approach.

Abstract:As a category of electroactive polymers, dielectric electroactive polymer (DEAP) has been referred to as “artificial muscles” owning to their excellent overall performances including large deformation, high energy density and high speed of response. As a new smart material, dielectric electroactive polymer can be used as a new energy harvesting method to transform mechanical energy into electrical energy when being combined with wind power and water power. The energy harvesting mechanisms and working cycles of dielectric electroactive polymer generator were investigated. Based on the analysis of energy conversion cycle, circular energy conversion unit was implemented to conduct analysis and experiment. The mathematic model of cone dielectric electroactive polymer generator was developed. With the proposed model, the forcestrokes of dielectric electroactive polymer generator in the stretching process and retracting process were determined. Analytical results indicate the generated energy and efficiency increase as the bias voltage and displacement increase in a certain range of bias voltage, while over high electrical field reduces electrical energy and efficiency due to charge leakage. Both analytical results and experimental data illustrate that the stretch displacement and bias voltage are the main factors contribute to electrical energy generation and the efficiency. With the application of multiple transducers, the overall efficiency of the proposed system could increase to above 28%. At the same time, the numerical waves of input torsions become smaller. This paper could provide a strong support for design of dielectric electroactive polymer transducer.

Abstract:Based on the piezoelectric principle, in consideration of adhesion, interaction between asperities, elastic-plastic deformation of the substrate, microcantilever elastic recovery and so on, the dynamic characteristics between microcantilever and the substrate rough surface driven by piezoelectric were simulated by using ABAQUS finite element software. The results showed that there were several significant contactseparation cases during the contact process of each piezoelectric driving. When no voltage was applied for 2~4μs, bonding between beam and the substrate still appeared. A small portion of the elasticplastic deformation on the rough surface occurred during separation, and the maximum residual stress appeared at the edge of the contact area. With the increase of piezoelectric driving times, the effect of surface bonding enhanced and the plastic deformation region on the substrate rough surface extended to two sides continuously, which influenced the reliability of the contact system.

Abstract:Compared with single hemispheresegment, hemispheresegment group has better forward and reverse unequal fluid resistance properties. In order to analyze the impact of flow resistance variation on pumping performance, the changes of row number, column number and intervals for hemispheresegment group in pump chamber were studied. Forward and reverse flow resistance coefficient formulas of hemispheresegment group were derived and verified by the flow resistance experiment and flow rate experiment of the pump. In the range of limited row and column intervals, the experimental and theoretical flow resistance difference and flow rate increased along with the increase of row and column numbers. At the driving voltage of 120V and the driving frequency of 6Hz, the valveless piezoelectric pumps with hemispheresegment group in rows and columns 3×4, 4×3, 4×4 respectively obtained the pump flow rates of 45.5mL/min, 46.2mL/min, 47.75mL/min The maximum deviation of theoretical relative to experimental flow rate was 23.23%. The results showed that the flow resistance law of hemispheresegment group could be used to analyze and predict the pump flow rate; the pump output flow rate can be increased by increasing the row number or column number meanwhile properly limiting the row interval and column interval. The better output performance can be obtained by increasing row number than column number.