Abstract:The combustion characteristic and cycle-to-cycle variations of a DI engine using oxygen-enriched intake air (the volume fraction of oxygen as follows:21%, 23%, 25% and 30%) and water-diesel fuel emulsions (the amount of water was 0％, 10％, 20％and 30％ by volume) were investigated. In-cylinder pressures of 20 combustion cycles and maximum pressures under economic speed and medium load operation were recorded. Consequently, cycle-to-cycle variations of maximum pressures and combustion characteristic were analyzed. The results reveal that, under the conditions of pure diesel, with the increase of oxygen concentration, the maximum cylinder pressures increase, and the cyclic variability of the maximum cylinder pressures and the ignition timing decrease. Using water emulsion diesel, with the increase of volume fraction of water, the ignition timing increases, but it still decreases with the oxygen concentration increasing. When the fraction of water is over 30%, the ignition delay increases dramatically, the in-cylinder burning deteriorates, and the variations of maximum pressure grow.

Abstract:The main influencing factors of starting system under low temperature were analyzed, while maximum output power of the ISG motor was determined. According to starting resistance torque, minimum start-up speed, electrical operating characteristics, electric transmission coefficient and thermal effects, the influence of plate structure on battery capacity was also reviewed. The match relationship among starting resistance torque, ISG motor power and storage battery capacitance was summarized, and the changes of starting resistance torque along with ambient temperature and starting speed has been measured. The experiment result shows that as far as the environment temperature decreases by 5℃, starting resistance torque increases by 3~5N?m at above 200r/min; keeping speed constant, starting resistance torque increases by 4～11N?m with every enhanced 50r/min. The first fire speed of ISG diesel engine at -25℃ is increased, which is up to more than 350r/min .The starting time is shorter than original diesel engine, and fluctuations in speed is smaller.

Abstract:A non-thermal plasma reactor was designed based upon dielectric barrier discharge theory. The non-thermal plasma assisted catalyst system was established with a Na-Rh/γ-Al2O3 catalyst system. The experiment was carried out and the reduction of diesel engine harmful emissions had been investigated with NPAC technology. Results showed that the particulate matter was reduced effectively and the maximum of soot removal efficiency was around 58%. The NOx emission was decreased remarkably by NPAC system. Under the low load conditions, the speed of 3 600r/min was corresponding to higher NOx conversion, and the maximum conversion was around 81.5%. Under the high load condition, the speed of 2 000r/min showed higher NOx conversion. 

Abstract:The characteristics of gasoline spray after wall impingement from a high-pressure gasoline direct injection injector were investigated. To examine the effects of various factors on the impingement development, experiments were conducted at different injection pressures, ambient pressures, wall distances and angles. The impinging spray development, spray height, spray radius, and spray growth rate were measured. Experimental results show that the spray penetration increases with the increase of injection pressure, wall distance and angle. The penetration decreases with the increase of ambient pressure. High injection pressure and low ambient pressure increased the fuel contact area and accelerated the evaporation. The predicted penetrations with the empirical equations in all cases agree with measurements, to a certain extent.

Abstract:Based on the design requirements of non-overload centrifugal pump, blade outlet angle β2, blade outlet width b2, throat area Ft and the inlet diameter of short blade Di, all of which affects the performance of centrifugal pump with complex impeller were chosen to design nine centrifugal pump models with complex impeller. Numerical simulation of whole flow field based on Fluent was adopted to do orthogonal test, the important order of geometric parameters affect the performance of centrifugal pump with complex impeller. The best design scheme for pump model was acquired. Through the test of specimen of the best design scheme, it demonstrated that the excellent selection by using numerical simulation of whole flow field was non-overload and high efficiency. Orthogonal test based on numerical simulation of whole flow field was verified by the research result.

Abstract:A decomposition-dynamic programming aggregation method, which was applied to solve the mathematical model of daily optimal operation with adjustable-blade for multiple pump units in single pumping station, has been proposed. Taking minimal daily electric cost as objective function, the water quantity pumped by units as coordinated variable, this model was decomposed into several sub-models of daily optimal operation with adjustable-blade for single pump unit, in which the blade angle was taken as decision variable, the discrete values of water quantity pumped by each unit as state variable, and was solved by means of dynamic programming method. The constructed aggregation model takes water quantity pumped by each pump unit as decision variable, the discrete values of water quantity pumped by pumping station as state variable, and was also solved by dynamic programming method. This method could solve the optimal operation issues for multiple pump units with different types or performance differences in single pumping station. Taking operation of No.4 Huaian Pumping Station as a study case, a set of optimization results was obtained.

Abstract:In order to develop a new type of precision spraying equipment, a set of variable-rate spray system based on electric control valve device as a converter was developed, and the step response characteristics of the system were studied by using experimental methods. The result shows that the maximum rise time is 1 s in the condition of step amplitude ΔQ=0.4, 1.4, 3.4, 3.9, 4.4L/min, which is comparable with variable-rate spray system controlled by changing flow press; the rise time, peak time and overshoot show correlation with the amplitude, which indicates that the system belongs to nonlinear system. So the control design of this type of variable-rate continuous spray system must take nonlinear problems into account.

Abstract:For the sake of rational exploitation and utilization of shallow layer underground saline water in Huang Huai Hai Plain, through the serial saline water farm irrigation experiment during the years of 2003~2005 at Nanpi Ecological Experimental Station of Chinese Academy of Science in Hebei Province, irrigating winter wheat with saline water of 3g/L, the long term effect of soil salinity, soil solution content, electric conductivity as well as winter wheat yield irrigated with saline water were analyzed. The objective of above works is to establish a rational saline water irrigation program of winter wheat in North China and to supply a theoretical basis for utilization of saline water. The results showed that the salt was cumulated on upper soil layer when the saline water of 3g/L mineralization degree was utilized continuously, and plant would be subjected to salt stress, especially, in the rainfall deflection crop year. Yield will increase when irrigated with saline water comparing with that of dry farming and the yield is higher with three times irrigations than that of twice. The repeated saline water irrigations should be avoid if the precipitation is small.

Abstract:On the basis of the non-sufficient and sufficient water supplied infiltration test of homogenous soil, the infiltration processes for both non-sufficient and sufficient water supplies were analyzed; the correlations of Kostiakov three model parameters for the non-sufficient and sufficient water supplies were established. The result shows that the ponding infiltration process with non-sufficient water supply accords with asymptotic curve of infiltration process with sufficient water supply; the infiltration parameter ratio m increases as the three elements of water supply, namely, intensity, clay content of soil grain and soil bulk density augment, while the parameter ratio m decreases as the two elements of sand content, and moisture content, the steady infiltration rate of non-sufficient water supply equals to steady infiltration rate of sufficient water supply; the infiltration coefficient K1 of non-sufficient water supply equals to the value of the difference between water supplied intensity of water supply and steady infiltration rate.

Abstract:Through laboratory evaporation experiments of soil column with different heights and mulched at different open-hole ratios, the difference of the distributions of soil water and soil salt and their connections were studied at different heights of soil column. The results showed that, the variations between cumulative evaporation at unit depth and evaporation time fit Gardner’s theory for all the soil column heights. There were 2-variable linear functions between cumulative evaporation at unit depth, evaporation time and total soil height. There was relatively good relationship between cumulative evaporation at unit depth and total soil height as well as open-hole ratios. There were also relatively good relationship between cumulative evaporation at unit depth by unit area of film holes and total soil height as well as open hole ratios. The smaller the total soil height, the larger the variation ranges of soil salt content at unit depth and soil salt concentration. The total soil height was a factor that influenced on upward movement of soil salt. Because plastic mulch with open holes restrained soil water evaporation rates and also affected accumulation of soil salt on soil surface, it was effective to decrease soil salt accumulation on soil surface by decreasing open-hole ratios of plastic.

Abstract:A simple visual device for scheduling irrigation based on pan evaporation for drip-irrigated cotton under plastic mulch was designed, and an irrigation scheduling model based on field water budget was established. The most suitable plant-pan coefficient for drip-irrigated cotton under plastic mulch and the indicators to schedule irrigation were determined in field conditions, while a revision method for the indicators was proposed under rainfall conditions. The field test proved that it was an effective way to program drip-irrigated cotton irrigation, once marked, there was no need for human intervention beyond checking the position of the water level in relation to the irrigation control marks. The suitable irrigation intervals based on pan evaporation at 140, 75, 50 and 120mm and irrigation water amount of 0.15, 0.4, 0.7 and 0.25 times of accumulated pan evaporation for seedling stage, bud stage, flowering and bolling stage, and boll opening stage, respectively, could be recommended for drip-irrigation cotton under plastic mulch in the north of Xinjiang area, China.

Abstract:Based on the analysis of high-speed cutting principle, the numerical simulation of a flow field within the crushing chamber in pulverizing process was performed by CFD technique, and Fluent software, in which RNG k-ε turbulence model was adopted. The effects of impeller blade shape, blade angle and impeller speed on the flow field were revealed, and the crush velocity, pressure, and shear strain rate were analyzed. The linear relationships between the impeller speed and various parameters were obtained. In case of straight blade impeller with 2° deflection angle the obtained flow field shows the optimal efficiency for cutting crush. The experiments for various materials indicate that the high-speed cutting grinder has the broad prospects with physical adaptability and smashing effect.

Abstract:Based on mechanism of processing bamboo fiber by combing method, a concept of average combing strength was put forward. Calculation model of relationship between average combing strength of fiber and fiber length and fineness was established with dynamic principle. The model was analyzed and validated, and the results showed that the model of bamboo fiber length and fineness against average combing strength, roller speed and comb-pins parameters was correct. The values calculated for bamboo fiber length by the model agree well with the experimental values. The length and fineness of bamboo fiber can be calculated by the model.

Abstract:In order to meet the requirements of digital design technology of agricultural equipments, a virtual experiments system platform on agricultural equipments by using MultiGen Creator, Vega Prime software and VC++ programming language was developed. The whole component of the virtual experiment system platform was introduced, together with its function, framework, and system process. Furthermore, the methods, processes and other key techniques related to the modeling process were discussed as well. The key techniques and difficult points of Vega Prime application were analyzed, such as dynamics simulation of custom model and realization of motion. The experimental results show stable operation of the system with the reliability and validity.

Abstract:A field information acquisition instrument for positioning, rapid and simultaneous measurement of soil moisture content and compaction was designed. Based on the measurement theory and the software and hardware design of the instrument, the accuracy of measurement was analyzed. 30 soil samples were taken from a tree nursery with the sampling interval of 5 m×5 m. The soil moisture content was measured by the field information acquisition instrument and drying method, respectively. The correlation analysis of the measurement values was carried out and the correlation coefficient is 0.9179. In the same way, 30 samplings of soil compaction in deeps of 10cm and 20cm were measured by the field information acquisition instrument and SC900 digital soil compactness instrument. The correlation analysis to the measurement values of tow depths by both methods was carried out and the correlation coefficients were 0.8267 and 0.9245, respectively. The test results showed that the measurement accuracy of acquisition instrument for the soil moisture content and compaction in field satisfied the requirement of agriculture production.

Abstract:0.804和0.759。By using self-developed portable instrument for crop nitrogen monitoring, the information of rice canopy reflectance spectra was obtained from the field experiments with two rice varieties and four nitrogen application rates, and the rice plant was sampled from each plot for measurement of leaf nitrogen concentration (LNC) simultaneously. The correlations and the quantitative relationships between LNC and rice canopy reflectance spectra were analyzed, and the performance of portable nitrogen monitoring instrument was evaluated. Results show that its ability in monitoring nitrogen is excellent, and its performance is steady in field condition. Testing the correlations between LNC and canopy reflectance spectrum of four characteristic bands included in the instrument, the correlations in the mono-band of 660nm, 710nm and 810nm are all more than 0.5 with a significance testing (p<0.01). During the all growth stages, the coefficients of determination R2between LNC and spectral vegetation index （VI）with double-bands are more than 0.7, especially in the flowering and mature stages (R2＞0.83). In the whole growth period, the VI are significantly correlated with LNC, such as NDVI（810,710）and NDVI(710,546), the determination of coefficients R2 are 0.804 and 0.759. 

Abstract:Considering carbon partial conversion and heat loss of the system, a thermodynamic model of biomass gasification was established based on mass balance, energy balance and chemical equilibrium, which was solved with Newton-Raphson method. The model is validated by comparison with the literature data. The effects of air preheat temperature, moisture content, reaction temperature and equivalence ratio on gasification performance were analyzed by the model. The detailed process of modeling and the calculating results are valuable for the development of the biomass gasification.

Abstract:As a new energy project in recent years, biomass power generation is playing a significant role in social and economic life. Recent years, more and more biomass generation projects have been approved, however, some of them are suspending and some are suffering from running troubles. So, it’s very important to build an evaluation system for running and managing such projects. An evaluation system based on the fuzzy synthetic evaluation approach and AHP methods was established in this work, which had been testified effective in practical applications and can be taken as an advisable example of starting and running biomass power generation projects.

Abstract:With compost, ZVI, and ZVI-compost as reaction media respectively, the feasibility and effectiveness of Cr-polluted groundwater by PRB were studied. The results showed that the reactor packed with ZVI-compost had a better performance than that with compost or ZVI alone; increasing the amount of compost ZVI could increase the removal effects; moreover the removal effects were little influenced by the time of composting; totle iron of effluent meet the requirement of standards for drinking water quality. 

Abstract:In order to improve the accuracy and robust of NIR spectroscopy modules in predicting the firmness of strawberry，simulated annealing algorithm (SAA) was used to select the wavenumbers in NIR spectra. A preprocessing method was also selected to adapt the SAA. Firstly, 150 strawberries were selected to collect NIR spectra. Secondly, preprocessing methods, such as SNV, MSC, 1st order derivation, 2nd order derivation, were used to denoise the NIR spectra of strawberry. Thirdly, 24 wavenumbers were selected by simulated annealing algorithm. At last, partial least square was employed to establish the calibration models of firmness. The calibration model was obtained with the correlation coefficient rc of 0.9342, the root mean square error of calibration of 0.665N/cm2 and the correlation coefficient rp of 0.9197，the root mean square error of prediction of 0.673N/cm2. The results show that SAA can improve the robust and accuracy and simplify NIR spectra models.

Abstract:Prediction ability of visible/near-infrared spectroscopy for intramuscular fat content assessment on-line was studied. Totally 208 longissimus dorsi muscle samples were collected from different carcasses. Sample spectra were scanned while the samples were moving at the speed of 0.25m/s. Wavelet transform was employed to eliminate the spectra noise. Partial least squares regression (PLSR) based on the de-noised spectra, combined with different pretreatment methods, was explored to predict intramuscular fat. Daubechies of vanishing moment6 at decomposition level 6 with the minimax threshold gave good de-noising results. PLSR model based on the de-noised spectra without any pretreatment had poor prediction performances. And through pretreatment, including multiplicative signal correction (MSC), standard normalized variate (SNV) and derivative, the performances are improved. The first derivative spectral in conjunction with SNV yielded the best PLSR model with correlation coefficient of 0.892 and 0.834 in calibration and validation sets, respectively, alongwith root mean square error of calibration of 0.090 and root mean square error of 0.080 for validation. Results indicate that it is possible to predict intramuscular fat content on-line. However, the best ratio of the standard deviation to the SEP of the validation set (RPD) value was 1.738, and the accuracy and the robustness of the model needed further improvement for practical on-line application.

Abstract:The effects of hypobaric storage under different pressures on the physiological and quality characteristics of flesh-melting textured juicy peach fruit were studied. The pressures were controlled at (10±5)kPa and (80±5)kPa, respectively with air storage as control. The results indicate that hypobaric storage not only significantly slows down respiratory and ethylene production rates, but also inhibits the decreases of fruit firmness, L*, titratable acids and Vitamin C contents. Hypobaric storage can maintain higher SOD and CAT activities, maintain the stability of membrane system, and retard occurrence of senescence and decay. Hypobaric storage under (10±5)kPa can extend the storage life up to 30 days. It is concluded that the hypobaric storage is an effective method of prolonging the postharvest life of juicy peach fruit.

Abstract:Viscoelastic properties of Korla pear (Pyrus bretschneideri rehd) tissue osmotically treated in iso-, hypo- or hypertonic sucrose solutions were investigated using oscillatory shear and creep-recovery tests. Results indicate that storage moduli (G′) is much higher than loss moduli (G″) over the entire frequency range. Both G′ and G″ show frequent independent, but increase with the increasing of turgor. In creep testing, the creep compliance responses of low, normal and high turgor tissues were characterized by a generalized Kelvin-Voigt model with six elements. The instantaneous (J0), retarded compliance (J1 and J2) and steadystate fluidity (1/η0) increased as turgor was reduced. By scanning electron microscopy (SEM), many rheological parameters (G″, G′, J0, J1, J2 and 1/η0) show the marked changes among the three turgor levels, which relates with the changes of cells and intercellular spaces due to the turgor manipulation.

Abstract:A mathematical model was developed for the heat and mass transfer in vacuumizing process. Computational fluid dynamics technology was employed for simulation based on the unsteady model. The simulation results fitted experimental data well. After that, several parameters (pumping speed, free volume, and clapboard etc.) which would affect the flow field were analyzed. The higher the pumping speed is, the lower the pressure limitation is, the lower the minimum air temperature of vacuum chamber is and the more time spent in reaching minimum temperature. The free volume did not affect pressure limitation of the vacuum chamber. The greater the free volume is, the higher the minimum air temperature of vacuum chamber is and the less time spent in reaching minimum temperature. Referring to the pressure limitation and the average temperature of the flow field, the placement of clapboard can be equivalent to the reduction of free volume. 

Abstract:The effect of heat inducible gelatin of salt soluble protein of venison on water retention property, breakdown strength and viscosity was investigated. The conclusions was as follows: as the amount of NaCl, sodium hexametaphosphate, sodium pyrophosphate and sodium polyphosphate increase, water retention property and breakdown strength increase first and then decrease, viscosity increases gradually; as pH value increases, water retention property first increases strikingly and smoothly then, breakdown strength and viscosity first increase and then decrease; as the temperature increases, water retention property first decreases and increases then, breakdown strength first increases and decreases then, and viscosity first increases and decreases then. The relation between affecting factors and water retention property, breakdown strength and viscosity was discussed through homogeneous experimental design and quadratic regression equations. The effect of factors on water retention property is as follows: the effect of sodium pyrophosphate and temperature is not notable while interaction effect among factors is notable. The influencing factors on breaking strength and viscosity are as follows: odium hexametaphosphate, ionic strength, temperature, pH value, sodium polyphosphate and sodium pyrophosphate, and interaction effect among factors is notable.

Abstract:CaCl2豆腐。Compared with tofu gelating by CaCl2, the differences between okara-containing tofu and control tofu in composing component, color, texture, microstructure and water holding capacity (WHC) was analyzed. The results show that their color difference is 3.76, which could be discriminated by naked eyes. Okara-containing tofu is darker than control. Because of soybean polysaccharide and cellulose, okara-containing tofu has the higher yield and WHC than control, and the effect of CaCl2 concentration decreases on okara-containing tofu. Due to the interaction of polysaccharide and protein, the okara-containing tofu is in chaos of block microstructure, while the control has an ordered and refined networks structure in SEM. Because polysaccharide interferes with the formation of protein networks, which weakens the gel strength, the okara-containing tofu has the lower value than control in the hardness, springiness and chewiness.

Abstract:In order to improve enzymolysis technology for preparation of angiotensin-converting enzyme(ACE) inhibiting peptides from oat-seed protein by alcalase protease, ultrasonic pretreatment of oat-seed protein solution was investigated. Based on the inhibitory activity of ACE and degree of hydrolysis (DH), the effects of ultrasonic power, pretreatment time and the on-off time ratio on ultrasonic pretreatment efficacy were studied. The results show that the optimum conditions of ultrasonic pretreatment are 500W of ultrasonic power, 20min of pretreatment time and 2s/2s of ultrasonic on-off time ratio. Under the optimum conditions, half inhibiting concentration (IC50) value of ACE decreases from 0.533mg/mL to 0.299mg/mL, and the time of enzymolysis reduces from 90min to 60min. Experiments also show that ultrasonic pretreatment parameters have made a significant impact on ACE inhibitory activity while no significant effect on the DH. It is verified that the increase of protein hydrophobicity caused by ultrasound is one of main reasons for significant improvement of hydrolysates ACE inhibitory activity. 

Abstract:25.68%提高到61.39%。In order to select suitable macroporous resin, to improve the purity of pumpkin polysaccharide and to determine purification process parameters, 9 kinds of macroporous resin were chosen to carry out static and dynamic adsorption-desorption experiments. With the indexes of adsorption capacity and elution rate, the suitable macroporous resin was selected and process parameters were confirmed. The results show that D101-I resin has the best performance of adsorption and desorption effects for purification of pumpkin polysaccharide, the optimum technology parameters are sample concentration of 4.79mg/mL, sample volume of 3.2BV, flow rate of 3BV/h, 25% ethanol for elution, elution velocity of 4BV/h, elution volume of 3.6BV. The purity of pumpkin polysaccharide increases from 25.68% to 61.39% by using the above technology. 

Abstract:Purification process of triterpenes in Cyclocarya paliurus by macroporous resins was studied. The suitable macroporous resin was screened, the technological conditions of purification were studied, and the optimum purification processing was obtained by the static adsorption and desorption tests as well as dynamic adsorption and desorption tests. The results show that, in three types of the experimented macroporous resins, D-101 macroporous resin presents the best effect of separation with the adsorption capacity and desorption rate of 57.5mg/g and 96.51%, respectively; through dynamic adsorption experiments, the optimum sampling rate and mass concentration is 2BV/h and 1.5mg/mL respectively; through dynamic desorption experiments, the optimum ethanol content is 50%, with eluting velocity of 2BV/h By macroporous resin, the purity of Cyclocarya paliurus triterpenes is 4.1 times higher than crude extracts, the recovery reaches 74.66%. In conclusion, D-101 resin can be applied to purify triterpenes in Cyclocarya paliurus. 

Abstract:2cm。An apple recognition method with normalized color difference (R-G)/(R+G) was presented. The apples in the images taken under different lighting conditions were recognized. Some pretreatments were applied to get contour images. The shape features of the apples were extracted from the contour images based on the method of random circle ring. A matching algorithm based on area feature and epipolar geometry was discussed to position the apples. The apples with similar areas were matched according to the principle of left-right order consistency by calculating the maximum value of cross-correlation function of vertical projections. The experiments results show that the proposed recognition method can eliminate influence of shade, and soil, to a certain extent. The recognition rate reaches 92%. The circle centers and radius are extracted precisely and rapidly based on the method of random circle ring. The errors are less than 2cm when the measure distance is between 60cm and 150cm. 

Abstract:A new type of end-effector was developed based on flexible pneumatic actuator (FPA), which was designed as a bending joint. The mathematical model of bending joints and end-effector was established with mechanical analysis method, the relationship between pressure and bending capacity, as well as the relationship between pressure and output bending force was analyzed. The mathematical model for end-effector of crawling apple was built. The experimental results show that the force of the end-effector is quite strong and the actuator can grasp apples perfectly and flexibly. 

Abstract:95%。The control technique of variable rate fertilization is introduced. Using single chip microcomputer as CPU, a control system of variable rate fertilization was designed, including force sensor, AD data acquisition system and servo-actuator. An assorted software was designed for selecting data and sending commands. Through test-bed experiment and analysis, the system can complete the control of variable rate fertilization, which has a simple structure, stable operation and high , fertilization precision up to 95%.

Abstract:A combined sensor for soil moisture content (MC) and electrical conductivity (EC) with 4-ring electrode was developed, based on the dielectric theory. The calibration tests with NaCl solution, moist soil sampler and mixed soil sampler were conducted. The results demonstrated that the combined sensor could response the variation of soil MC and EC. By means of analyzing the outputs of 4-ring sensor in mixed soil sampler, statistical prediction models for soil MC and EC were established, respectively. 

Abstract:Aiming at the two distinct phenomena appeared in the EC-5 sensor temperature experiment, a theoretical model on variation of soil moisture content with temperature was established according to the influence of temperature on soil permittivity and electrical conductivity. The simulation based on the model shows that the variation tendency of soil moisture content with temperature measured by the EC-5 sensor is closely related to the soil electrical conductivity. Using least squares support vector machine, the sensor temperature compensation function was built and corresponding compensation algorithm was proposed. The results of the experiment indicate that the sensor measurement errors caused by temperature are effectively offset.

Abstract:In order to heighten transmission distance and continuous monitoring, a remote collection and monitoring system of soil moisture content information was developed. Its structure and principle were described in detail, and the software and hardware design were given. The system can be charged by solar energy. Wireless transmission and satellite location of sample stations was realized by GSM net and GPS system. The large area real-time soil moisture content state was monitored and the spatial distribution map of soil moisture was drawn by a GIS software. The application results show that the proposed system is efficient. The established remote monitoring system provides reliable and foundation for fighting for drought. 

Abstract:In order to develop a method for rapid detection of moisture content in vinegar residue substrate, the spectral data of 69 representative samples were collected by using visible-near-infrared spectroradiometer, and the oven-drying method was applied to obtain the data of these samples moisture content. Partial least squares regression (PLS) method was selected to perform the calibration models for predicting the moisture content. For determining the number of principal component factors in the PLS model and the method of spectra preprocessing, the model with the lowest prediction residual error sum of square based on cross-validation for the calibration samples set was chosen. The determination coefficient between the predicted and the reference results for the prediction samples set, along with the root mean squared error of prediction (RMSEP), was used as evaluation parameters for the models. The results indicate that the forecast result of spectral data is optimal through the spectra preprocessing method of moving average filter (MAF) and first derivative (FD), with 5 principal component factors. The determination coefficients of the calibration and prediction models are 0.9930 and 0.9901, with root mean squared error of calibration (RMSEC) and prediction (RMSEP) of 0.0676 and 0.0715, respectively. Therefore， visible-near-infrared spectroscopy with PLS method can be used successfully to determine the moisture content of vinegar residue substrates.

Abstract:Taking detection of soil organic matter content as an example, this paper discussed the application method of empirical mode decomposition (EMD) for processing soil near-infrared (NIR) differential spectrum using empirical mode decomposition. And the principles and steps of processing were proposed. Then the soil organic matter content was calculated based on the de-noised spectrum, and it was compared with the result from the nine-point smoothing method and wavelet method. Experimental results showed that the SNR was improved from 3dB to 10dB, and the root mean square error of between raw signal and de-noised signal were reduced to 0.901 from 2.972. The correlation ratio of the prediction set was improved to 0.9803 from 0.9410, and the RMSEP was reduced to 0.3011 from 0.6702. This improved that EMD is effective to get the pretreatment of NIR spectrum, and the EMD method improves the accuracy of near-infrared spectrum detection of soil organic matter content. 

Abstract:9.5%。For an electro-hydraulic vibration exciter with a 2D valve, the frequency and the amplitude of the excited waveforms are separately controlled by rotary motion and sliding motion of valve core, respectively. Based on the work principle of the an electro-hydraulic vibration system, the mathematical model of an exciter was established. The equations of excited waveforms were solved by using the subsection integration method, and the real excited waveforms were obtained to validate the theoretical analysis result. The corresponding spectrum analysis and the distortion calculation were executed. The results reveal that in low frequency section, the ascent and descent slopes of excited waves demonstrated somewhat asymmetrical because of the changing direction of the elastic load. The extent of asymmetry depends on the axial opening of 2D valve. The waveform distortion is not greater than 9.5% as long as the linear opening of 2D valve is below a critical point. 

Abstract:As a new type of electroactive polymer (EAP), dielectric elastomers can work in both actuator and generator modes. Dielectric elastomers (DE) can achieve good performance in a generator mode, such as high energy density, good impedance matching to many energy sources, low cost, etc. Based on the structure of dielectric elastomers film, the fundamentals of dielectric elastomers, namely fundamentals of alterable capacitance are discussed. The theoretical models of dielectric elastomers film were analyzed, and the conclusion that Maxwell stress effects could be treated as a piezoelectric material with an effective piezoelectric coefficient was drawn. Power energy conversion cycle was analyzed by simulation and experiments, and the experimental curves of output voltages were investigated. The relation between electric field and elastic restoring stress, and its influence on power generating efficiency, were discussed. At last, the mechanical cycle of power generation for dielectric elastomers was determined approximately.

Abstract:A two-link flexible structure system consisting of a flexible bar and a flexible beam was proposed．The coupled bending-torsional vibration of the flexible structure system was investigated．The dynamic equation of the system was established. A piezoelectric torsional actuator was bonded onto the root of a flexible bar to suppress the torsional vibration of the flexible bar, and a piezoelectric bending actuator was bonded onto the root of the flexible beam to suppress the bending vibration of flexible beam．Experimental research was performed using a sliding mode variable structure control strategy with a saturation unit and a filter．The results show that the controlled system is stable, all the bending and torsional modes are effectively suppressed and the tip vibration of the flexible beam is dramatically attenuated．

Abstract:A lifting oil cylinder support with floating support structure was designed by the topological optimization technology. The hydraulic pressure lifting system was simulated by AMESim software, and the load curve and the maximum load of the lifting oil cylinder support were obtained during lifting. Based on the maximum load, the load and its effects on the frame carling were analyzed by FEM. Afterward, the comparison and analysis were done among floating support structure and the other two traditional structures of jointing on bottom steel board structure and carling structure. The analytical results indicate that the lifting oil cylinder support with floating support structure is obviously superior to the other two structures. 

Abstract:With the blind number theory, the mechanical structure’s time-dependent characteristic based on stochastic process was deduced. The uncertain variables in time-dependent stochastic process of mechanical structure were expressed in blind number, and its time-dependent reliability calculation model based on blind number theory was built. And what’s more, the corresponding program in LabVIEW language was given, and a free beam’s time-dependent reliability was also computed. The result showed that blind number as a kind of numerical tool is very convenient and effective for solving the complicated reliability calculation model.

Abstract:Aiming at detecting bearing fault information, which is easily to be submerged in heavy noise and whose characteristics is nonlinear and non-stationary, a method of fault diagnosis based on empirical mode decomposition (EMD) and Duffing oscillator was put forward. This method decomposed the original signals using EMD to find intrinsic mode function (IMF) of containing the fault information, then the dividing value of force making the Duffing oscillator phase orbit changed was got, the inner motivation force frequency was set to the same frequency as the bearing fault, at last the fault was determined according to the change of Duffing oscillator’s phase orbit. The results of experiments show that this method can detect the fault of bearing successfully. 

Abstract:A large-scale, direct computational model of crankshaft system was established for dynamics simulation and calculation of fatigue life of a crankshaft. The dynamics model was solved by use of high-performance-computing (HPC) technique and explicit finite element method. The calculation result describes the crankshaft dynamics characteristics including strength and distortion in detail. The fatigue life evaluation on crankshaft was accomplished by S-N analysis method straightly utilizing dynamics simulation result and the analytical result based on dynamic stress-time history makes it more reasonable. The computational process and calculation result prove the feasibility and validity of this method for a crankshaft system.

Abstract:The cutter location compensation method is often used for unequal diameter machining of globoidal cam surface. A new calculation method for the normal error is developed, and a self-adaptive cutter location compensation optimization algorithm is proposed, whose objective is to minimize the maximal normal error. This algorithm can find out the best compensation direction and value by the cutter location optimization for any cam rotation angle and make the cutter location self-adaptive and flexible compensation according to the machining error. The normal error calculation formula has been proved to be valid by an example. A conclusion has been drawn that the radius difference between the cutter and the roller is the best compensation value and the best compensation direction is not fixed. The results show that the correctness and effectiveness of the improved self-adaptive compensation method have been proved and machining errors can be evidently reduced. 