破碎大米入仓过程分级问题理论研究

通过观察粮食在入仓过程中产生的物料自动分级现象,研究了自动分级在矩形筒仓储粮装粮过程中空气阻力带来的影响。根据牛顿第二定律对粮食下落运动时进行受力分析,建立物料入仓到装粮完毕在仓内的运动方程,并且根据物料下落过程中不同的受力情况推导出物料大米垂直落下与水平抛出时位移与时间关系方程。通过理论计算得出物料自由下落时间,随着物料粒径的增大而减小。根据分析,提出有效缓解物料自动分级的措施,减少损失。     

THE ALGEBRATIC CRITERION OF THE UNCONDITIONAL STABILITY OF THE THIRD-ORDER LINEAR RETARDED DIFFERENTIAL DIFFERENCE EQUATIONS

The sufficient and necessary conditions of the unconditional stability of the third-order linear retarded differential-difference equations with constant coefficients are given. The conditions are brief and practical algebratic criterion.     

THE UNIQUENESS OF FLAT SOLUTION ON SOME FUCHSIAN EQUATIONS

This paper studies the uniqueness of flat solutions on some Fuchsian equations. First, Carleman's estimate for a first order P_sDO is proved, then the uniqueness of the solution of first and second order Fuchsian equations are proved by classic method. Finaly, the uniqueness of t-involutive equations is obtained.     

THE INSERTING SYNTHETICAL METHOD FOR COMPILING NETWORK STATE EQUATION

This paper begins with the analysis of factors affecting the esta-blishmet of network state equations. On the basis of characteristics of networkclement, a rational formntation order of elements as twigs and links is proved.According to the order, a best tree can be drawn, which is helpful to for-mulate state equations, Two examples are enumerated On the basis of the besttree, topological equations of network are written. By inserting operationswith both topological equations and characteristic formulas, a standard stateequation is derived as a result of eliminating the undesired variables. Thismethod is simpler and more convenient as compared with the others in theand has advantage of both the topological method and the direct operations,method.     

THE ELIMINATION OF UNDETERMINED MULTIPLIERS OF MOTION EQUATIONS OF NONHOLONOMIC SYSTEMS

This paper studies several kinds of motion equations of nonlinear nonholonomic constraint systems. On the basis of the motion equations of the first order nonholonomic system and the theory of the zero factor of matrix multiplying from the left, the general equations of the system without undetermined multipliers is derived. By applying the method to arbitrary order nonholonomic systems, the motion equations of the systems are gained.     

THE MATRIX METHOD FOR ESTABLISHING DISCRETE SYSTEM DYNAMIC EQUATIONS

In this paper a matrix method for establishing discrete system dynamic equations is presented. Using this method to establish discrete system dynamic equations, netting but the derivative of function, and matrix multiplication are required. This method suits to the holonomic system as well as the linear nonholomic system.     

THE CALCULATION OF INTERNAL FORCES AND DISPLACEMENTS IN FRAME-SHEARING WALL STRUCTURE UNDER THE HORIZONTAL LOADS

In general,the calculating result of a comparatively regular frame-shearing wall system in tall buildings,a 4-order differential equations are established according to the deformation-coordination of beams,columns and four boundary conditions.Then a series of formulas concerning internal forces and displacement is obtained These formulas are hyperbolic functions.This paper presents a method,which changes 4-order differential equations into 2-order and solves them by the expressions of new homogeneous solutionThen the formulas of internal forces and displacements become exponential functions By this method,the calculation is very convenient The result of suggested method agrees well with the general by comparison This paper is also applicable to buildings with some part of different height of storey or stiffness.     

THE EVALUATION OF SHEAR STRENGTH TAKING ACCOUNT OF SPAN-TO-HEIGHT RATIO OF SIMPLE BEAMS UNDER UNIFORM LOADS

By introducing the span-to-height ratio,this paper deduces wo evaluating equations of shear strength of simple reinforced concrete beamwith stirrups and under uniform loads.This makes the shear stressing concept consistent with the evaluating equations,thus improves the evaluating equationsof shear strength of the New Code.Two equations are provided with auto-regulating function on shear strength for a cross section of beam.They aresimple and convenient in evaluation.The working time used for design is not increased and 10% of stirrups is economized in frequent conditions of span-to-height ratio.     

ORTHOGONAL COLLOCATION METHOD AND IT APPLICAIONS IN THE CALCULATION OF DYNAMIC CHARACTERISTICS OF HEAT EXCHANGER

Being a kind of MWR, the orthogonal colloacation method can be conveniently used to reduce the initial-boundary value problems of the partial differential equations to initial value problems of ordinary differential equations. In this paper, the orthogonal collocation method is introduced in detail and by using it the dynamic characteristics of a steam-water heater are investigated.     

THE COMPILING OF EIGHTH AND SIXTEENTH ORDER MAGIC SQUARE

This paper introduces how to compile the mathematic model ofeighth and sixteenth order magic square and how to change twofold magic squ-are problem into onefold magic square problem.The twofold magic square is made by solving liner equations and thus the difficulty of making the twofoldmagic square is reduced.     

THE ANALYTICAL EQUATIONS OF HYDRO-THERMAL POWER SYSTEM ECONOMIC DISPATCH

The paper developes the analytical equations of the power economic dispatch by using the modified coordination equation, it also developes the explicit functional relation between the hydro-coal conversion factor and the daily water consumption. Using these expressions,the calculating amount of the hydro-thermal system economic dispatch is greatly reduced and the convergency is much better. Finally a numerical example is given to show these advantages.     

THE PERFORMANCE EVALUATION AND REALIZATION FOR UNCONSTRAINED OPTIMIZATION SOFTWARE

In this paper, we propose some basic concepts of the performance evaluation on testing unconstrained optimization software and furtherdesign a performance testing package-OPTEST-1, which is used to test optimization programs on three areas: systems of nonlinear equations, nonlinear least squares, and unconstrained minimization. We also describe criteria of the performance evaluation, system functions, and the approach of performing OPTEST-1.     

THE APPLICATION OF MULTIBODY DISCRETE METHOD IN RING''S VIBRATION ANALYSIS

A ring's muJtibody discrete model is discussed in this paper. The ring's plane geometric nonlinear vibration equations are derived. Compared with the finite element and lump mass methods, this method is better. In the last pa it of the paper, the eigenvalues, the first 9 modes of the ring, the geometric nonlinear dynamic responses of the ring are calculated.     

INFLUENCE OF THE GEOMTRIC PARAMETERS OF LOW FINNED TUBE ON BOLHING HEAT TRANSFER AND OPTIMIZATION OF THE PARAMETERS

On the basis of the mechanism of the boiling heat transfer on low finned tube, the influence of the geometric parameters of low finned tube on boiling heat transfer is synthetically analyzed and relevant criteria which affect the optimal structure of low finned tube is deduced in this paper. The boiling heat transfer experiment on low finned tube is conducted. Distilled water and R-113 are used as test fluids The experiment is performed at local atmospheric pressure. Synthesizing a large amount of experimental data, the semiempirical equations for the optimal geometric parameters of lowfinned tube are established     

THE INCOMPLETE PARAMETER METHOD IN SYNTHESISING PLANAR SIX-BAR MECHANISM

28 to 70 nonlinear equations are required to solve for the path synthesis of planar six-bar mechanism when using the method of displacement matrix, this brings on a great deal difficuties in solving the problem and heavily limits the applied scope of the method. In this paper an incomplete parameter synthesis is presented in which the synthesis of six-bar mechanism is sim-plified to those of bar-group or four-bar machanism so that the solution becomes much easier.     

THE REAL RESISTIVE MODEL FOR FREQUENCY -DOMAIN ANALYSIS

A new model for frequency - domain analysis - the real resistive model which is based on Complex Network Theory is proposed in this paper. The network equations formed with the new model without contain complex numbers because there are only sources and resirtive elements in the model. A CAA algorithm for frequency analysis by using the new model is also given. It is shown that the trouble with the complex operation in the traditional algorithm has been avoided. The algorithm presented in this paper is simple and convenient,hence it is easy to popularize.     

ANALYSIS OF THE DYNAMIC STABILITY OF DUALEXCITED SYNCHRONOUS GENERATORS WITH NON-DAMPING WINDINGS

This paper analyses in detail the dynamic stability of thedual-excited synchronous generators with non-damping windings,and sets up theundamental equations and the linearized mathematical model for small distur- bance analysis.By an example with computer results,the paper also compareshe difference of the dynamic stabilities between the single-and dual-excited synchronous machines,which explains that the dual-excited synchronous gene- rators can increase the dynamic stability of machines under certain conditions.     

THE CALCULATION OF FLOW USING SEMI-IMPLICIT METHOD FOR PRESSURE-LINKED EQUATIONS

This paper briefly introduces Patankar-Spalding Method, which is systematical, active and widely applicable in numerical heat transfer and fluid flow. The corresponding dependent variables, diffusivities and source terms for the general differential equations under all circumstances are explained. By using this method the calculation of two-dimentional Poiseuiue Flow and Couette Flow compared with exact solutions are proved to be high precision. with two-dimentional path-flow in the heat convertor intersification devices as an example, the tilted method is used with FORTRAN 77 programming, and the calculation is done on a SIEMENS 7570c minicomputer.     

THE STUDY OF SINGLE CHIP COMPUTER BASED SYMMETRICAL COMPONENT DISTANCE PROTECTION

In this paper, a new microcomputer distance protection scheme with high property-cost ratio has been approached. The paper presents the performance equations based on the symmetrical components of current and voltage, proposes a new (1,a) coordinate plane and derives a Fourier symmetrical component algorithem with high accuracy and less calculation amount on the (1,a) plane. The protection program is debugged on the developing system of single chip computer. The digital imitation tests indicate that the proposed relaying system is satisfactory.     

LARGE DEFLECTION OF A CIRCULAR PLATE ON PASTERNAK FOUNDATION UNDER A CONCENTRATED LOAD AT THE CENTER

Based on Karman's nonlinear foundamental differential equations, the new method combines perturbation method with integral equation method is forward to solve nonlinear bending of a clamped circular plate on Pasternak foundation under a concentrated load at the center. This method is simple and easy to use. The numerical results show that the present solution is reliable.