Abstract:实验研究了内插螺旋线圈的水平圆管内30~#透平油的对流强化传热及流阻特性,探索了螺旋丝径的影响。实验圆管为φ10×0.5×900mm的紫铜圆管。其它参数范围为:193.97≤Pr≤464.36;2.7×10~2≤Re≤2.5×10~3;0.333≤t/D≤1.333和3.75≤t/d≤24.实验表明,Re及丝径的增大均使换热系数及阻力增大;Re的增大亦同时造成h/h_及△P/△P_两个比值的增加。Pr的减小可使换热增强,流阻减小,采用(Nu/Nu_)/(f/f_)~(0.29)作为评估传热及流阻综合性能的判据,实验范围内该判据之值介于2.09～3.23之间。此外,综合实验数据得到了传热及流阻两个关系式。

Abstract:This paper presents the experimental results of convective heat transfer performance in 5 copper tubes with three dimensional internally extended surface, with flow of various test fluid in the Reynolds number range of 8,000 to 80,000. Water and mixture of ethylene glycol with water (the ethylene glycol weight content equals 55%) are chosen as test fluid. The effect of the physical properties for test fluid on heat transfer performance in the tubes with three dimensional internally extended surface is discussed. The heat transfer correlation is obtained by the experimental data.

Abstract:Based on a thermomechanically consistent mechanical model consisting of springs and plastic dashpots, a plastic constitutive equation for large deformation is derived. Then the incremental form of elastoplastic constitutive equation is developed, which can easily be applied to the finite element analysis and other numerical approaches. The method for the determination of the involved material constants is suggested, which is based on the concept of nonstress configuration proposed by Lee. The necking process of a circular bar subjected to large elastoplastic deformation is simulated and the comparison between the analytical and experimental results is quite satisfactory. The developed model does not use the eoncept of a yield surface, which effectively improves the convergence and computation efficiency.

Abstract:Author gives out his views of point on some fundamental concepts commonly used in soil mechanics based on author' s understanding. Discussed properties of soils include: ELAS- T1CITY and PLASTICITY, discussion is focused on how different definitions of elasticity have the effect on theory verification. HOMOGENEITY and MICROSTRUCTURE. Pore motion and evolution and the sublayer of microstructures, which consists of heterogeneity, is the essence of intricate mechanical behaviors of soils. MACRO-FIELD and MICROFIELD. The first is how to express micro-field complextely ,fractal may be a useful tool. The second is how to connect the complex index with macroscopic mechanical behaviors. A method is suggested which considers energy dissipation mechanism in microscopic scale. DILATANCY and DEVIATORIC PLASTICITY. A definite relation is verified by many experimental data. Author derived out it from a micromechanical model. Discussed recognition theories include two:RELATIONSHIP BETWEEN DRUCKER POSTULATE, I-LYUSHIN POSTULATE and IRREVERSIBLE THERMODYNAMICS. The postulates are the direct sequence of entropy inequality, expressing complementary energy (Drucker) and free energy (I-Ivushin) reach maximum and minimum respectively,and are unnecessary for plasticity. So it is impossible to describe total behaviors of soils based on them. MACRO / MICRO COMBINATION THEORIES. A simplified micromechanics method, whose material functions and constants determined by macroscopic test data,makes micromechanics applicable in engineering. Other problems are also discussed in this paper.

Abstract:An analysis is made for various kinds of possible breakdown modes during hydrofracture,and the corresponding breakdown pressure,from which a method is given to distinguish which kind of failure mode practically occured. The analysis shows that the initial failure mode at the wellbore wall may be the pure tension failure or shear failure according to different stress states and mechanical properties of rock,therefore there are two different stress state configurations resulting in vertical shear fractures.

Abstract:The communication of the application program among work tations of 3+ network is realized by the shared file on harddisk of the network server,which does not support the application program' s real-time communication among the network workstations nor supplies software or hardware needed for information refreshing, nor fits for field multibatch continuous real-time transmission and processing of working condition information, by using the NETBIOS function call method, the real-time communication among network workstations is realized and a power plant working information background real-time communication and data processing system is developed which effectively traces working condition from tow 200 MW power plant generators, altogether 321 points from a cycling detecting system and 78 binary points for broadcasting the information to other workstations,and realizes a complx display of 14 working condition graphs and a real-time data simulation graph.

Abstract:This paper shows a scheme for intersection traffic real-time sign-controlling, by which the most optimized green-time can be achieved during a sign period. The optimized objection is traffic density. A loop-dector is requested for each approach,and the dynamic flow is simulated. So that it is possible for predicting the density disbrution during the next period. The model is characterized by real simulation and real-time.

Abstract:The relations between reliable communication networks and reliable multi-bus structures are investigated in this paper. By means of the graph theory we can easily design a reliable network,which then can be made further with the help of a multi-bus structure.

Abstract:The method that the MASM assembler is interlaced to the MS-FORTRAM 5. 0 is used to store some step structural mode drawings in the designated disk file through their visiting VRAM,which are then restored in it when needed in order to realize the quick animation display of the mode. This method solves the problem of insufficient memories in storing multistep structural mode drowings with the ordinary method. As a functional modular of finite element analysis programs SAPS and ADINA transplanted to a microcomputer,the modular programed with the above method can quickly display the animation of large structure with multistep modes.

Abstract:The structure of FCC: BCC partially coherent interface is simulated by computer. The results show that the interface structure is varied with the orientation relationships. The structural models of varied orientations are made, which are defined by the lattice parameter ratio afcc/abcc= 1. 26 and ranged from K-S to N-W orientation relationship. The amount of deviation of the apparent habit plane from atomic habit plane {111}fcc is a function of orientation,and ranges from ca. 12 degrees to ca. 30 degrees. Computer simulations also found that the misfit dislocations could not be certain to exiet on the FCC:CC partially coherent interface.

Abstract:The solidification microstructures and their nucleation models are discussed,and the effect of the shape effect of moving melton pool on the solidification features is anslyzed on the basis of experiments. The experimental results show that its solidification behavior is complex,because the continuous laser alloying is a dynamical process. The reason for this complexity is that the dynamical solidification characteristic is significantly controlled by the laser alloying parameters and the molten pool shape. On the other hand,the solidification structures of laser alloying have a series of specialities,and their nucleation mechanisms are mainly heteroepitaxial growth and heterogeneous nucleation growth.

Abstract:In order to investigate how to increase the concentrate sintering productivity,the particle properties of the concentrate have been studied. It was found that the essential reasons for low sintering productivity are the difficulties to pelletize and poor permeability because of particle' s size bigger,smooth surface, poor activity and hydrophobe.

Abstract:In this paper,the adherence and thermal barrier properties of A12O3-based ceramic metal gradient coating with the method of oxyacetylene-flam-spray are studied. The results show that the physical and chemical compatibilities between the coating and the substrate are improved by adding Cu,Ni/Al and the gradient coating,and to relax thermal stress and interface stress in coat and at the same time to increase adherence property of coating. Besides,the gradient coating has good spalling resistance,erosion resistance to high temperature liquid iron and the effect of thermal barrier properties is remarkable.

Abstract:The boundary-value problem for the electrostatic field with anisotropic media is formulated on the basis of introducing the medium property coefficient tensor. The boundary integral equations for this problem are deduced by the weighted residual method. The elementary solutions to the two-and three-dimensional anisotropic problems are derived. A two dimensional example with anisotropic media is given.

Abstract:The operating mode of the single-phase capacitor-run induction machine is analyzed with the theory of double rotating field. Since there are two stable generators and two stable motor operating speed regions,with the balanced operation condition the better speed region can be decided for the generator,i. e. reverse direction of the rotor.

Abstract:The status quo of heauy-metals pollution in water phase of course of Long-Tan hydropower statian was eualuated by water Quality Standand Level Method. With this special method,mone objectiue and definite results were obtained.

Abstract:In this paper two reasons-the deviation of the data from the origin and the size of the data-causing the ill-conditioned normal equations in the least square fitting of a polynomial are discussed. And a method to improve the ill-condition is put forward. The method is the data processing in advance. By the means of the data processing in advance the spectral conditional number can be reduced greatly,then the result of the fitting is reliable.

Abstract:本文讨论了排队系统M/M/n、和GeO/Geo/n的K(K ≥0)阶忙期,给出了K阶忙期的分布和前两阶矩的简单表达式。

Abstract:A three critical point theorem is proved. As its applications, Dirichlet problem for a class of quasilinear elliptic equations cf second order is considered.

Abstract:Based on the definition about the idea of Flexible Manufacture Systems(FMS), a three dimensional systematic views to represent the concept of the FMS production planning and scheduling problem is presented firstly. Next,a four-layer framework model of FMS' s production scheduling problem is put forward. Then, the operations research models and techniques in the static and dynamic scheduling of FMS operation are systematically analyzed, and the existing difficulties are pointed out. Finally,a brief introduction about the trend of using other approaches,such as artificial intelligence (AI) and artificial neural network (ANN), to solve the FMS planning and scheduling problems is given.

Abstract:This paper deals with the force property analysis,strength design and use of the clutch-screw press.

Abstract:The basic theory of multi-rigid body system kinematics is introduced, the idea of train component method which relates to kinematics analysis is presented. Using the above theory and method,this paper makes kinematics analysis for the four-axle steering system of LT1080 autocrane.

Abstract:Under the condition of imitating the smelting process.the investigation has been carried out to the properties of melt dropping behaviours and reduction for several kinds of vanadium titaniferrous magnetites,such as sinter,pellet and lump ores;and especially the relation between the mineral constitute basicity of ores and its high temperature metallurgical quality is studied with its influence on the reduction process at the low and high temperature zones and the titanium reduction. So the reasonable burden mixture of smelting vanadium titaniferrous magnetites is high basicity sinter and acidity pellet. However,with the existing conditions of the steel plant.it is essential to improve the basicity of the sinter.

Abstract:对南桐煤田的青年矿煤样、南桐矿煤样及鱼田堡矿煤样的导电性质进行了实验测定和理论研究。研究表明,在实验电场强度范围(3.3×10~3～1.7×10~5v/m)内,煤的电阻率是外加电场强度的函数,随着外电场强度的增高,煤的电阻率将下降。实验结果还表明,煤的变质程度越高,其导电性也越好。