PREDICTION OF QUATITIES CONTROL OF STRAIGHT BEVEL GEAR SHAPING

Based on the forming and meshing theories of gears, the relationship between machining parameters and driving quatity of straight bevel gears has been discussed. The forming and meshing processes have been simulated with a microcomputer. The correctness of the theoretical analysis and calculation has been proved by shaping experiment.     

水稻地上鲜生物量的高光谱遥感估算模型研究

不同氮素营养水平的水稻田间试验,采用单变量线性与非线性拟合模型和逐步回归分析,用1999年试验数据为训练样本,建立水稻鲜生物量的高光谱遥感估算模型,用2000年试验数据作为测试样本数据,对其精度进行评价和验证.结果表明,高光谱变量与地上鲜生物量之间的线性与非线性拟合分析中,一些高光谱特征值如红边波长(λr)、绿峰最大     

THE ERRECT OF HIGH HARMONICS ON THE SELECTION OF THE SIZE OF TRANSFORMER CONDUCTOR

This paper analyses the additional stray losses of transformer winding caused by harmonics,and suggests that the influence of harmonics should be taken into consideration in the selection of the conductor' s size in rectifier transformer and converter transformer design.     

水稻数量性状的基因效应分析

利用9个水稻品种杂交得到11个组合的 P_1、P_2、F_1、F_2和 B_1、B_2世代群体的数据进行了世代平均值分析。文中估算了 a、d、aa、ad 和 dd 各类基因效应、其相应的方差及平方和百分比。分析发现世代间有显著差异,其差异大小取决于杂交双亲。8个性状中加性率超过50%的是出穗期、株高和百粒重。穗长和总粒数的加性率与显性率之     

THE ANISOTROPY DISCONTINUITY MODEL DUO TO THE STRIKE OF THE TAGGED DISCONTINUITIES

In this paper, on the base of the original shapes of discontinuities in engineering gedogy, we mainly discuss the ralations among the shape of discontinuity, the restraining effects of discontinuity deformations (including the normal deformation and the shear deformation ) and the crustal stress. Then we put forword the concept of the pseudo-dilatancy ungle which can indicate the motion direction, set up the anisotropic discontinuity model, and give some important results and formula for illustrating truly the discontinuities in rock engineering.     

The Affection of Learning Mechanism to Unequal Strategic Alliance Partnership

Some symmetric mathematical models, such as Tech-Tech or Tech & Market - Tech & Market, had been set up in the researches of theoretical models of cooperative behavior among firms in strategic alliances. An asymmetric model is established in this paper by discussing the Tech-Market type strategic alliances and expressing the strength contrast between the partners in an alliance by the Bass diffusion models. The benefits changes of alliances partners are studied in several different occasions, and the model about the influences of learning upon partnership is built by introducing the learning mechanism to retrofit the Bass models. Then it is proved that the learning mechanism possesses strategic significance to the partnership, that is to say, the development of an alliance is beneficial to the partner who has higher learning efficiency and unfavorable to the other one. At the same time, the original cause of the strategy, i.e., gaining foreign investment and technology by let foreign firms own some domestic market share, was not work well in last ten years in China, has been revealed. It is pointed out that China's firms should do their best to improve their learning efficiency when they participate in the international alliances.     

THE PRINCIPLE AND EXPERIMENT OF TRANSIENT LINE-SOURCE METHOD FOR MEASURING THERMAL CONDUCTIVITY OF BLOOD

According to the analysis of one-dimensional radial unsteady heat conduction in an infinite medium,a transient line-source method to measure thermal conductivity of blood is provided, which is effective,accurate and easy to be carried out. By means of this method,it takes only a few seconds to accomplish the measurement. This would be a particular advantage for blood since it coagulates very quickly. With a simple apparatus,experiment has been performed and the results match the existing data of blood' s thermal conductivity very well.     

THE APPLICATION OF TNE SPATIALLY MECHANICAL THEORY OF ROBOT

A kinematic simulation model has been designed for a cantilever manipulator ofhydraulic exacvator and the kinematic performance of a 20 t hydraulic excavator' s cantilever ma-nipulator is simulated on IBM-PC/XT microcomputer.     

“食品分析”实验课教学模式的改革探索

“食品分析”课程是一门技能性、实践性、科学性很强的专业基础课,传统的教学模式已经不能适应时代发展的需要。因此,教学团队对该课程的实验课进行了教学模式的改革与实践探索。经过2年的实践证明,“食品分析”课程改革有效促进了学生的学习兴趣和积极性,评定学生的学习成绩更加合理,获得了较好的教学效果,进一步提高了学生的培养质量。     

大豆表观接触弹性模量的测定

利用质构仪按照美国农业与生物工程师协会ASAE S368.4DEC2000(R2006)标准,结合大豆的生理结构特点,对2011年东北黑龙江产大豆样品分别从长(L),宽(W),高(H)对应的Z、Y、X三个方向进行了压缩实验,测量了加载载荷与对应变形量的关系,运用SPSS软件对数据进行分析处理.得到大豆的表观接触弹性模量、最大破坏力、最大破坏能、破坏点的变形量、破坏点的变形百分比。     

Performance Simulation of EHE for 300MW CFB

With the development of circulating fluidized bed boiler(CFB),the study field of external heat exchanger(EHE) is greater in extent and degree.In order to research the working process of EHE,the model which deals with flow and heat transfer of EHE for 300MW CFB of Dong Fang Boiler Grou PCo.Ltd.is presented.Based on the cell modeling theory,the EHE is divided into several chamber by heating surfaces.The mass and energy conservation equations of each cell have been developed according to some reasonable assumption.The complete mathematical model has been compiled by Fortran and solved by classical Algorithm of Runge-Kutta.The static test and perturbation experiment of simulating model has been performed.The simulation results show that the model has been reached the steady state rapidly,the dynamic responses are reasonable and the modeling presented in the paper is reliable and appropriate.     

广东省小麦分蘖成穗、幼穗形成、籽粒灌浆特性与高产栽培的关系

研究表明:广东小麦具有分蘖期短,成穗少,分蘖高峰期出现早,高峰持续时间长;幼穗分化早,分化期短,小花退化晚,退化集中;籽粒灌浆期长等特点。在广东的生态条件下,根据小麦上述特点对品种选用、增产途径、播种期、培育壮苗以及防止后期阴雨天气对籽粒灌浆等影响,趋利避害,以达到高产稳产,提出一些看法。     

Study on Software for Hydraulic Model Experiment on Chencun Waterway in Zhujiang Delta

In this paper,the software developed on the basis of Windows platform is introduced, which is used in Chencun Waterway hydraulic model experiment. The efficiency in data analyzing and post processing has been improved. Since the various techniques in Windows platform (such as OLE, DDE) has been adopted, the development works are more efficient and an experimental analytic software with powerful and perfect functions can be developed conveniently.     

AN ON-LINE ALGORITHM FOR PREDICTING THE TEMPERATURE OF POWER TRANSFORMER WINDINGS

The paper presents an on-line algorithm for predicting the average temperature of power transformer winding according to its load current. The algorithm has accounted for the whole history of load current and variations of ambient temperature. The overload capabilities of transformer can be increased by monitoring and controlling the winding temperature and the necessary durability of the transformer can be ensured. The algorithm can also forecast the future winding temperature and the time of reaching the max, permitted the assumed future load current and oil temperature.     

Mathematical Model of Selective Catalytic Reaction of Nox in Reactor and Its Simulation

As the domestic technology of selective catalytic reduction(SCR) has not been mature.A assembled-parameter dynamic mathematical model is established for the primary chemistry reaction process in SCR reactor.The mass balance equation of the NH3 adsorption-desorption on the catalyzer surface and six gas components,and total energy balance equation in SCR reactor are set up respectively.A dynamic simulation model has developed by using MATLAB simulation tool.The steady calculation for model is carried on.Based on the established dynamic simulation model,two dynamic simulation experiments have been done,which include the simulation experiment of step disturbance about NOx concentration and temperature.The simulation results current is correctl.The analyzed results indicate that the established dynamic mathematical model for SCR reactor is credible,and prove that the simulation model is practical.     

THE PRECISE SOLUTION OF MATHEMATICAL MODEL FOR TWO-STEP CARBURIZATION TREATMENT

The precise solution of mathematical model for two-step carburigation has been induced which is under the condition of the third boundary. This solution has been compared with the finite difference technique and its correctness and practicality have been proved.     

CropSyst, a cropping systems simulation model

CropSyst is a multi-year, multi-crop, daily time step cropping systems simulation model developed to serve as an analytical tool to study the effect of climate, soils, and management on cropping systems productivity and the environment. CropSyst simulates the soil water and nitrogen budgets, crop growth and development, crop yield, residue production and decomposition, soil erosion by water, and salinity. The development of CropSyst started in the early 1990s, evolving to a suite of programs including a cropping systems simulator (CropSyst), a weather generator (ClimGen), GIS-CropSyst cooperator program (ArcCS), a watershed model (CropSyst Watershed), and several miscellaneous utility programs. CropSyst and associated programs can be downloaded free of charge over the Internet. One key feature of CropSyst is the implementation of a generic crop simulator that enables the simulation of both yearly and multi-year crops and crop rotations via a single set of parameters. Simulations can last a fraction of a year to hundreds of years. The model has been evaluated in many world locations by comparing model estimates to data collected in field experiments. CropSyst has been applied to perform risk and economic analyses of scenarios involving different cropping systems, management options, and soil and climatic conditions. An extensive list of references related to model development, evaluation, and application is provided.     

近红外光谱法测定玉米秸秆纤维素和半纤维素含量

为了解玉米秸秆资源可转化碳水化合物物质基础,建立了玉米秸秆中纤维素及半纤维素近红外分析模型。利用傅里叶变换近红外漫反射光谱(NIRS)技术和化学计量学软件,结合偏最小二乘法(PLS),通过光谱采集,进行了近红外光谱模型预测及验证。探讨了不同预处理方法对玉米秸秆纤维素和半纤维素含量的NIRS模型影响,获得理想分析模型,相关系数(R)≥0.909。实验结果表明模型对纤维素、半纤维素含量预测平均相对误差为2.34%和2.13%,预测值与化学值误差较小。说明该模型可准确、快速并大量检测玉米秸秆中纤维素和半纤维素含量,提高秸秆生物质资源利用率,促进生物质转化工艺过程。     

THE TEMPERATURE RESTRAINT STRESSES ON THE LAYER-FACE OF PHOTOELASTIC MODEL WITH VARIABLE ELASTIC MODULUS

The producing mechanism and developing law of the temperature restraint stresses on the layer-face of photoelastic model with variable elastic modulus are investigated with experimental studies and theoretical analysis, and the stability of the fringe figure of the restraint stresses or the fixedness of the restraint is verified repeatedly with the experiment. Thus the single model method of eliminating the influence is put forward, and the formula with superposing of fringe parameters of the method is given. The single model method is of great importance to eliminat the influence of the restraint stresses on photoelastic modelling with variable elastic modulus for soil and rock engineering and improving the experiment accurcy.