A STUDY OF THE OPTIMIZATION OF CIRCULAR ARC TOOTH PROFILE TRANSMISSION

For the first time, we point out the new idea that we can approximate the involute tooth profile transmission to circular arc tooth profile transmission. Looking upon it as a fourbar linkage we try to minimax the error of the velocity ratio and evaluate the strong-weak point of circular arc tooth profile transmission.     

大米水分测量结果不确定度的评定

对大米水分的测量结果标准不确定度、扩展不确定度及不确定度表述进行了系统的分析和评定,并编写了相应的计算程序,对测量结果不确定度评定中的建模、分量计算、合成标准不确定度、扩展不确定度的评定和计算方面作了有益的尝试.描述了影响大米水分测定结果各分量对其不确定度的相对贡献.     

谷物通风干燥的数学模拟及试验

根据已发表的谷物干燥数学模型编写了谷物通风干燥模拟计算程序。利用该程序玉米,稻谷在不同干燥条件下的干燥时间,计算干燥过程中沿气流运动方向谷堆各点的水分及粮温变化,并可对谷物机械通风干燥的性能进行综合分析研究。     

水稻早熟性的初步研究进展

水稻早熟品种在农业生产上有重要意义,根据水稻早熟高产育种的理论基础,初步提出培育早熟高产稻组合的各种可能途径并阐述国内外水稻早熟性品种遗传模式且对当前预测杂交水稻生育期杂种优势的方法进行简要概述,以期为水稻遗传育种的利用提供参考。     

Research on Error Automatic Revised Method of LSI Wafer Honing Process

A new automatic revised method of wafer profile error which uses CCD measuring error,sets up machining data base and carries out a wedge structure for stepless compensating error in honing process is described.Using this technology,a high precision LSI wafers can be obtained.     

APPROXIMATION OF INVOLUTE PROFILE BY MOON-SHAPED RING SECTION

In this paper,we study the approximation of involute profile by moor-shaped ring section. By using the minimax method, we find parameter of the best approximation moon-shaped ring section of invelute piofile. The error of approximation is 35% - 70% that of [1] and [2]. Thus the approximation precision of dressing a wheel for involute gear forming-grinding by approximating method has been greatly improved. In order to simplify calculation, the error function is defined according to the implicit equation of curve and its rationalization is proved.     

THE NEW SECTION PLANE OF NORMAL CYLIDRICAL WORM TOOTH FLAND ERROR ON THREE COORDINATE MEASURING MACHINE

The concept of "New Section Plane" has been proposed when the tooth flank error of normal cylidrical worm is measured on the three coordinate measuring machine .and it has been compared in many respects with the general" First Section Plane". It has been pointed out that "The New Section Plane" is superior to "The First Section Plane     

An Exchange Algorithm for the Best Chebyshev Normal Approximation by Quadratic Curves

According to the criterion of measuring profile error,a mathematical model for the best approximation to profile of gear is presented;the characteristic of the best quadratic curve approximation is derived.An algorithm and its convergence are discussed.Finally,the quadratic curve approximations to the profiles of many gears are obtained efficiently by the algorithm.The approximation errors are less than 0.8 micrometers.     

INVESTIGATION ON THE FORMATION OF SINE IMAGE OF RECTANGULAR GRATING

OTF of a diffraction - limited incoherent imaging system is equivalent to a linear filter of the spectrum of the intensity when thesystem focusing error is very serious,we derive a formularand these results of calculation agree with the experimental data, which is exact explanation to the sine image of rectangular grating.     

DEVELOPMENT AND TEST ON ROLLING CONE ENVELOPING HOURGLASS WORM PAIR

The rolling cone enveloping hourglass worm pair has been successfully developed, in which there is almost only rolling friction between the meshing tooth surfaces, and both the worm and wormwheel have hard surfaces. Such a new type of hourglass worm pair is particularly-favorable for power transmission. This paper presents the design. manufacting and testing of this worm pair.     

冬季供暖工况下混凝土辐射顶板传热特性

针对冬季供暖工况下混凝土辐射顶板的传热问题,建立顶板辐射供暖的简化数学模型,利用MATLAB软件计算其供热量,并通过该顶板辐射供暖的热工特性实验验证模型的合理性。研究表明:顶板温度计算值与实验结果的误差在5.01%以内,供热量计算值与实验结果的误差在5.15%左右。通过对实验和计算结果的分析发现:在定流量稳态工况下,顶板温度随供水温度的增大呈指数性增大,随换热盘管间距的增大而减小。     

小麦种子饱满度及其与灌浆特性关系的研究

通过对10个小麦品种不同灌浆期的种子测定，分析了各种灌浆特性及种皮收缩度与籽粒饱满度的关系，并计算出不同品种在达到1级饱满度时的粒重、灌浆速度、灌浆期等理论值，阐述了这些理论值在改良小麦品种籽粒饱满度的意义。     

INFORMATION THEORY COMBINATION FOR ERROR ANALYSIS OF. SAMPLING-QUANTIZATION FOR DIGITAL MEASUREMENT SYSTEMS

This paper presents a new error analysis method based on the information theory. The analyse results of error of a digital measurement system will be illustrated more reasonably. This method is defined information theory combination, it will overcome the unintention between the uncertainty and the standard error of measuring results by traditional error analysis. On the basis of error spectrum analysis of sampling and quantization, an optimum digital filtering method is also presented in this paper. Simulation and testing show that the method is more resultful.     

虚拟关节臂式坐标测量机模型的构建与验证

关节臂式坐标测量机的测量误差受到众多因素的影响,且由物理构件带来的误差无法被消除。为此,笔者旨在构建一种虚拟关节臂式坐标测量机。首先,采用D-H矩阵建立其运动学模型,其次,利用PC-DMIS测量软件分析测量机数据并对模型的精确性进行检验,最后使用蒙特卡罗法和测量机模型完成仿真测量。通过与实际参数构建的模型、制造商参数构建的模型相对比,可知所构建测量机模型的测量精度能够满足要求。仿真结果表明提出的模型构建与验证方法对坐标测量的应用具有较高的工程价值。     

THE RESEARCH OF AERODYNAMIC PARAMETER ABOUT THE PIPE-CASING GUN OF THE EQUAL ACROSS-SECTION

The computation principle for the pipe-casing gun of the equal acress-section area is studied by applying the basic theory of compressible. The aerodynamic parameter of the pipecasing gun and the friction factor of rustless sted-pipes and copper-pipes of different diameters are measured. On the basis of this measurement, the outlet-velcity profile and the change of the rate and pressure on the axis are measured. The results show that the friction factor measured is reliable and the computation method is practical.     

THE DECOUPLJNG CALCULATION OF MULTI-AREA POWER SYSTEM LOAD FREQUENCY CONTROL

The calculating burden of the decoupling judgement of multi-area power system load frequeney centrel is very large by tranditional methods. This paper changcs the decoupling judgement problem into a minimum cost network flow problem. The solution algorithm is out-of-kilter . algorithm which is characterized by simple manipaultion, fast and reliable convergence. In the paper, we discuss and calculate the decoupling problem of two arca power system load frequency control. The results show that the proposed approach is feasible and effective.     

THE NEW REAPPEARING TECNNIQUE 0F SKY LUMINANCE DISTRIBUTION WITH THE HELP OF TNE COMPUTER FIGURCAND NUMCRICALSYSTEM

This paper introduces the new reappear technique of Sky Luminauce distributionwith the help of the computer figure and numerica system. Using this program, we can obtain theluantitative figure of Sky Luminance distribtion much conveniently and accurately so that studyingabout Sky luminauce distribtuion goes a step further;     

Estimating canopy cover from color digital camera image of rice field

Canopy cover (CC) is a good predictor variable for plant growth parameters such as leaf area index and aboveground biomass. A nondestructive, low-cost, and convenient method is presented for estimating CC using digital camera image analysis. CC was estimated by the ratio of plant pixels to total pixels of digital camera image of rice field. To determine the criteria for segmenting the rice plant from variable soil background, three mosaic images for rice plant, flooded/bare soil, and algae-infested background were prepared from digital camera images that were taken in various field conditions. An image analysis program was developed in Visual Basic to extract red, green, and blue (RGB) features from the mosaic images, calculate RGB-based color indices, and compute the minimum segmentation error for separating rice plant from background. When judged by the segmentation error, modified excessive green index (MEGI) showed the highest potential for segmenting rice plant from flooded/bare soil background, followed by normalized green (g) and excessive green index (EGI). At the threshold MEGI value of 0.03, the segmentation error was the lowest as 0.13%. Any single index considered was not satisfactory in segmenting rice plant from algae-infested background. However, a discriminant function of 1.2553EGI + 0.01735G − 0.01474B was successful in segmenting rice plant from flooded/bare soil and algaeinfested background with segmentation errors of 0.34 and 1.17%, respectively. CC for four rice varieties from tillering to booting stage was estimated based on the threshold value of MEGI and discriminant function and also manually using commercial software. Both estimates of CC showed good relationship of r² = 0.94, suggesting that a digital camera could be used efficiently for measuring the CC of rice field.     

THE CALCULATION OF THE LNS INDEX OF LARGE GENERATORS USING PIECEWISE ALGORITHM BY CAPACITIES

If generator capacity were not graded, the error in reliability evaluation would increase along with the large-capacity generators put into use.In this paper, the method for calculating LNS Index of generators is analyzed and studied using piecewise "algorithm by capacity, it can be used in reliability evaluating of unspecified under loaded generators.