Determination of chemical composition and nutritional attributes of silage corn hybrids by near-infrared spectroscopy on chopper: evaluation of traits, sample presentation systems and calibration transferability

Determination of dry matter and feeding value of silage corn ( Zea mays L.) limits the number of genotypes that can be evaluated in breeding programmes. Measuring plot material by near-infrared spectroscopy on chopper (NOC) allows to increase the number of genotypes to evaluate, and improves dramatically the efficiency of the data collection processes. The objectives of our study were to (i) compare the performance of two NOC sample presentation systems (conveyor belt vs. spout) for determination of dry matter and feeding value of silage corn hybrids (ii) identify limiting parameters in the performance of alternative NOC sample presentation designs and (iii) evaluate the calibration transferability between NOC systems equipped with different sample presentation designs. Two chopper machines were equipped with near-infrared diode array spectrometers. Sample presentation designs comprised the conveyor belt and spout systems. Drying-oven and laboratory near-infrared spectroscopy were used as reference methods to develop NOC calibrations. In association with its higher dynamic signal range the conveyor belt system yielded lower standard errors of prediction than the spout system for most traits. Calibration transferability between NOC systems with different sample presentation designs was feasible.     

A load identification algorithm for contactless power transmission systems

When contactless power transmission (CPT) systems are operating normally, load variation will cause the system operating frequency to drift and the resonance frequency scope to deviate from the desired level. These fluctuations in turn cause the system to vary substantially and affect its normal operation. Considering the slip road track of the primary circuit and the phase angle change between the front of the sub network rectifier circuit current and the voltage, we employ different circuit models to analyze the nature and size of the load for the two types of anti perceptual situations. An algorithm is derived to calculate the junior circuit parameters with the load on the rails. Simulation analysis for the load identification under two different load conditions is conducted, and the expected results achieved.     

Modeling and control of An LCL bi-directional inductive power transfer system

Since there exist high-frequency switching networks and complicated operating modes in bi-directional inductive power transfer (IPT) system, it is easy to result in high harmonics and EMI interference. An LCL filter network is introduced to effectively filter out the unwanted harmonics in track current and reduce EMI interference. Based on a mathematical model of the power transmission established by complex analysis of the AC variables, under the condition of maximum transmission efficiency, the phase angle differences between the primary input voltage and secondary output voltage U·so are ±90° and the energy is respectively transferred in forward or backward direction. Moreover, the power magnitude can be controlled by adjusting the modulus of U·pi and U·so. In addition, to keep the track current constant, different phase-shifting control strategies are designed in the primary and secondary parts. Simulation and experimental results show that these strategies can not only adjust track current to keep constant but also dynamically change the direction and magnitude of power transmission according to the working conditions and actual needs of the system load to improve the system operating efficiency.     

Simulation of the Dynamic Performance of CHANASTAR Minicar with Automatic Transmission

According to the AT minicar project of Changan Automobile CO.Ltd.,the system for simulating the dynamic driving mode of the powertrain with Automatic Transmission is established.The engine and hydraulic torque converter are tested,and the character diagrams are protracted.The two parameter shift rule and the driver fuzzy control module are established.On the basis of dynamical equation,the kinetic model of car is established.With the system,the dynamic and economical performances and ten-mode driving status are simulated.The simulation results show that the system can simulate the actual driving status well,the dynamic and economical performances of the minicar basically meet the technical requirements.The theoretic foundation is provided to the project.The foundation of cruise control is constituted.     

An Attentive Problem of 35 kV Power Lines in Mountain Area on Protecting Against

To counteract capacitive current and resume power system, the neutral point of 35 kV power system at the mountainous area is grounding through the arc winding widely. In fact, there is great difficult in selecting the arc winding to satisfy the requirement of system. In a 35 kV power system which neutral point is grounding through the arc winding, the capacitance current are measured in site when a single-phase is grounding. From the measure data, the imbalance of three-phase voltage whether the arc winding exist or not and the operating situation of arc winding are discussed, and bring forward an attentive problem about operation of arc winding and decrease of lightning outage rates.     

A Sort of Design Model of Embedded Multitasking Real-time Operating System Applied in Chip

In terms of the design of Traditional Embedded Real-time Operating System(ERTOS),the authors make use of the integration and big Kernel structure,which has the limitation in some aspects,such as the retractable,portable,supportable for hardware platform with new structure and open for interface standard and so on.Based on the analysis of RTOS,a sort of design model of embedded multitasking real-time operating system is proposed.First,the hardware(abstract) layer and operating system kernel are studied.Then,the highly scalable,real-time,transplantable and application programming preface design of ERTOS are presented.This design model takes use of the hardware Bard Support Package(BSP) to support the transplanting in sorts of OEM board or hardware system board,therefore solves the questions in traditional system,and last meets the current need for ERTOS.     

Self Excitation Simulation for Hydro-Synchronous Generators

The capacity,voltage,and length of modern electric power system are increasing ceaselessly.Synchronous generators will cause self excitation with the help of armature reaction,its stator current and voltage will increase.The self excitation conditions and the transient process are two aspects for studying self excitation.Now,self excitation conditions are mathematical formulas under certain postulate.The model of transient process of self excitation is linear.The conditions of self excitation are presented based on simulation,and the results of self excitation effected by the electromagnetic parameters of hydro generators operating extra high voltage long transmission line are simulated,based on a saturation model of hydro generators.The conclusions are very helpful for operation and design of hydro generators.     

Electromechanical coupling experimental analysis of permanent magnet AC servo precision drive system

To research the dynamic characteristics of the permanent magnet AC servo precision drive system coupled with multi-factors, the experiment system is constructed with PMAC as the core and IPC as the support platform. Through software prototype system, response signals such as the current, speed and torque are acquired when the system is in the no-load and in the loading operating state, then the theoretical analysis results are compared with the experimental results. So the experiment validates that the electromechanical coupling analysis of the system is correct. This research helps to analyze the influence mechanism and law that the design parameters and electromechanical coupling parameters exerted on the system performance. At the same time, the research is beneficial for dynamic design of the permanent magnet AC servo precision drive system.     

Agroecological principles for the redesign of integrated crop–livestock systems

Combining crops and livestock within integrated crop–livestock systems (ICLS) represents an opportunity to improve the sustainability of farming systems. The objective of this paper is to analyse how agroecological principles can help farmers to redesign and improve the resilience, self-sufficiency, productivity, and efficiency of ICLS. Relying on case studies from Brazil and France, we examine how the transformation of two conventional, specialised systems into more integrated-production systems illustrates the different dynamics towards agroecological ICLS. The French case study, based on self-sufficient farming systems belonging to a sustainable agriculture network, highlights that cost-cutting management led to a win–win strategy comprising good economic and environmental performances. The farms decreased their dependence on external inputs and had only a limited loss of production. The past trajectories of the farms illustrate how increasing the interactions between subsystems improved the self-sufficiency and efficiency of the farms. The Brazilian case study compares slash-and-burn agriculture in the Amazonian region with the recovery of degraded grazing area by ICLS. A small increase in chemical inputs linked to a diversification of productions led to a large increase in production and a large decrease in environmental impacts (deforestation). The Brazilian case study also illustrates how the diversification of production increased the resilience of the system to market shocks. Reconstructing the links among soil, crops, and animals following agroecological principles could improve the different performances of ICLS. New agroecological ICLS, benefiting from diversified productions and increased interactions between subsystems, are likely to offset the trade-off between agricultural production and environmental impacts observed in current ICLS.     

Research on Current Situation and Trend of Control Strategies for Hybrid Electric Vehicles

The vehicle's driving performances is determined by the control strategies and constructions of hybrid electric vehicles (HEV). The constructions of HEV are classified according to the change of state of charge of battery pack, and a study on current situation and trend of control strategies for HEV is presented in this paper. The research indicated that the current control strategies for HEV are not perfect and need further optimization. The control strategies should realize the optimum match among engine, motor, battery and transmission according to the characteristics of each component and vehicle's driving conditions. Many aspects including the fuel economy, emission, the life of battery pack, drivability, the reliability of each component and HEV's manufacture cost should be considered in the control strategies. A study on the control strategies and its optimization that take account of the aspects mentioned above is a work emphasis in the future. This paper also points out the PHEV equipped with small motor, small engine and continuously variable transmission is an ideal system construction for getting optimal fuel economy, lower emissions, steady drivability, lower manufacture cost and HEV's mass.     

Control Strategy for Asychronized Turbogenerators

Asynchronized Generator can better solve the excessive reactive and stability problem in power system.In order to improve the dynamic and transient performances of an asynchronized turbogenerator(ASTG),excitation control equation of it in the dynamic synchronous reference frame is presented.Control results are simulated in the synchronous and dynamic synchronous reference frames for ASTG.It is shown that the dynamic and transient performances in the dynamic synchronous reference frame are better than those in the synchronous reference frame.Consequently,the control strategy of dynamic synchronous reference frame can shorten more time on the dynamic process of ASTG.     

SERIES-PARALLEL CORRECTION AND CAA FOR CANONICAL SYSTEM TYPE 2

This paper presents a simple and efficient engineering design method of series-parallel correction for canonical system type 2 and gives a practical design example.The following and anti-disturbance performances of the system by means of digital simulation are analyzed.The performance indexes in different design parameters are listed.This paper is available for reference in engineerng design.     

武汉与重庆典型地质结构下的地埋管换热性能

地埋管地源热泵换热器的换热性能受到不同地质结构的影响。以武汉和重庆地区的典型地质构成为边界条件,建立了三维地埋管的单孔双U管换热模型,通过模型计算,获得了两种地质条件下的地埋管换热性能,以重庆地区的地源热泵热响应测试结果以及工程运行数据出发,对模型的计算结果进行了验证,结果表明,模型吻合度较好,可以应用于工程分析。以模型为条件,进行地质结构对换热性能的影响度分析,预测了两地地埋管地源热泵的换热性能并计算得到换热器的平均换热系数分别为武汉地区K₁=1.65（W/m·K）,重庆地区K₂=1.51（W/m·K）。     

Overall control strategy and operational performances of a doubly fed wind turbine generator system

In order to comprehensively and correctly analyze the real-time operational characteristics of a grid-connected wind turbine generator system, it is necessary to analyze the overall control strategies and operation performances of the wind turbine generator system. According to the type of a doubly fed wind turbine generator system, the mathematical models of wind turbine, drive train and doubly fed induction generator (DFIG) are presented. From the viewpoints of the maximum wind energy capture and safe operation of the wind turbine, a maximum power output control strategy is proposed by considering the DFIG loss minimization, and a variable pitch control strategy is also presented by considering generator rotational speed restriction and the output power restriction. Combined with a power decoupling strategy of DFIG, the overall operational performances of the doubly fed wind turbine generator system are simulated. By comparing the simulation, theoretical analysis and actual operational data, the results show that the presented model and overall control strategies of the doubly fed wind turbine generator system are valid.     

Operational Analysis of Open Untreated Sewage Source Heat Pump System

The effective sewage intake technology is prerequisite for the untreated sewage source heat pump system to run steadily. In terms of the insufficiency of current sewage intake technologies, an open sewage intake integration technology is proposed. The mathematical model and the distinguish basis of critical state are established for the sewage intake characteristic by defining some important operating parameters, such as the blocking coefficient, the contamination density and the section coefficient. Furthermore, the change rule of each critical operation parameter is observed along with the various initial parameters. The result can provide the theoretical basis to design the open intake integration technology.     

Analysis on the Electrochemical Performance of Solid Oxide Fuel Cell

This paper studies the electric potential of Solid Oxide Fuel Cell(SOFC).The activation over-potential,ohmic over-potential and concentration over-potential are solved by recently published equations.This paper also discusses the influence of operating temperature and steam to the SOFC's operating cell potential.Through the research,it is found that the temperature have great influence on SOFC's cell voltage.When the current density is high,the SOFC's cell voltage is higher with higher operating temperature.The steam ratio of the fuel have effects on SOFC's ideal electric potential and over-potentials.In summary,the less the steam ratio is,the greater the cell voltage we can achieve.     

Improvement of Natural Gas Engines Power Performances

The reasons of the power performances reduction for gasoline/natural gas engine have been analyzed when natural gas is used. Every measurement and their technical states for improving the power performances of the engine have been summarized. It is a workable and economic measure that a mixer is designed optimally and the intake system is matched carefully with engine and the ignition-advanced angle is increased slightly. The measure of boosting and cooling induction gas can increase the performances and worth being studied further.     

农业大棚嵌入式无线温控系统设计

为了有效实施农业大棚温度动态实时监控,提出采用Zigbee无线网络和Linux嵌入式操作系统设计大棚温度监控系统。系统采用C/S结构设计,分为下位机和上位机2部分。下位机系统分为温度采集节点和汇聚节点,温度采集节点完成大棚内不同地点的温度信息采集和无线数据传输功能;汇聚节点除了完成数据中继任务外,还可根据上位机反馈的控制指令完成排风扇的打开或电热系统的开启工作;服务器端的上位机系统完成数据的储存和分析,并根据分析结果完成对下位机系统的实时控制。实践证明,该系统可精确监控大棚温度,有效降低布线成本,有助于降低劳动成本和提高农作物产量。     

机体弹性变形对主轴承润滑特性的影响

为揭示机体弹性变形对曲轴主轴承润滑特性的影响,在考虑整机体和曲轴弹性的条件下,建立发动机曲柄连杆机构多柔体动力学模型,耦合基于质量守恒边界条件的广义雷诺方程和Greenwood/Tripp接触模型,分析机体弹性变形对曲轴主轴承润滑特性的影响。结果表明：与刚性机体相比,计入机体弹性变形后,各主轴承的润滑特性随曲轴转角的变化趋势与将缸体处理为刚性时基本一致;润滑油平均端泄量和总摩擦功耗在一个工作循环内均变化较小;润滑油最小油膜厚度、最大油膜压力和轴承的最大粗糙接触压力在一个工作循环内的某些时刻变化明显。     

在两种环境条件下玉米八个农艺性状的研究

在两种截然不同的生态环境条件下,研究了由7个玉米自交系所组配的21个单交组合八个性状的表现、基因型与地点的互作以及一般和特殊配合力与地点的互作。地点平均数经 t 测验的结果,除百粒重、全生育期的有效积温和株高外,其余各性状均达0.01差异显著水平。八个性状的基因型及其与地点的互作均方都达0.01显著水平。一般和特殊