Abstract:A numerical study is carried out for the combined heat transfer of turbulent natural convection and surface radiation in an two-dimensional open square cavity with only one heated wall. The results show that the radiation significantly affects the velocity and temperature fields,and it can reduce the turbulent natural convection heat transfer as well as enhance it. For different Rayleigh number and temperature difference ratio,the overall heat transfer rates and the portion of radiation present different variation patterns.

Abstract:An implicit enthalpy solution is developed for analysis of one-dimensional conduction controlled phase change problems. The solution is based on separating the sensible and latent heat terms in an enthalpy formulation. By making the assumption of equal volume node-jumping,a variable time together with a fixed space grid is used to ensure that the phase boundary is always on a node point,so that the nonlinearity associated with the latent heat can be effectively dealt with via the source term. A freezing problem around a pipe with analytical solution is applied to demonstrate the effect of the present method.

Abstract:This paper presents a new method for the probabilistic stability evaluation of AC/DC power systems. The transient stability model is described and the stochastic factors having effects on the stability behaviors are analysed and modeled. A theorem governing the probabilistic relations among the occurences of different types of disturbances is derived. A method of parallel computation is oresented, which is based on Monte Carlo simulation. An illustrative example is also given to show the application of the concepts and method presented in this paper.

Abstract:This paper presents a decomposed optimization model for power network planning. The planning problem is divided into master problem to determine the investment decisions and subproblems to deterimne the operation decisions. In the proposed model, the effects of multi load levels,stochastic line outages,power loss cost and load curtailment cost on the investment decisions are considered. The results of the examples prove the feasibility and effectiveness of the proposed model.

Abstract:According to the basic idea of phasar analysis and by applying a special multiplier, a new on line and real time method is derived for determining harmonic current and reactive current of an electric network. This method has a good dynamic response characteristic and solves for the first time the determining problem for the compensation system in single phase system,which is also appliable to the three-phase system.

Abstract:A calculation formula of stirring energy in liquid steel is set up for bottom-blown O2 and CH,| in the combined blown converter, and the main factors which have an effect on stirring energy and the variation law of stirring energy in steel-making process are discussed.

Abstract:在研究板料的极限应变时,提出了一种新的初始几何缺陷模型——椭圆缺陷模型。用大变形弹塑性有限元法,按大变形J_2塑性流动理论,大变开J_2塑性变形理论分析了具有不同长短半轴椭圆缺陷模型,标准的M-K缺陷模型,圆形缺陷模型对双向受拉金属板极限应变的影响。分析结果表明,椭圆缺陷对双向受拉金属板极限应变的影响与椭圆的长短半轴比及椭圆区板厚有关。根据圆形缺陷模型算出的极限应变值是上限,根据标准的M-K缺陷模型算出的极限应变值是下限。圆形缺陷模型和标准的M-K缺陷模型是椭圆缺陷模型的特殊情况。分析还表明,大变形J_2塑性流动理论对缺陷比大变形J_2塑性变形理论更敏感。分析时,假定双向受拉金属板处于平面应力状态,在弹性、塑性状态下都是体积不可压缩的。

Abstract:在一类其定义域内无紧支集的函数空间~(-2)(Ω)上建立了一个带余项的Sobolev不等式。

Abstract:Norming M - decomposition and strong M -decomposition are introduced, and their characterization are given. The necessary and sufficient condition that the generalized biorthogonal system becomes unconditional Schauder decomplsiton is acquired.

Abstract:In order to improve the convergence rate of the algorithms, an acceleration search method along a straight or curve is proposed,and the specific calculation steps of the algorithms are presented. The numerical results in model parameter estimation show that the convergence rate is improved and the calculation accords with the practical demands.

Abstract:在Cole-Cole提出的阻抗轨迹图和RC三元件网络的基础上,设计制作了测量人体肢体细胞内外液分布阻抗测量仪。整个系统在微机控制下实现了全自动测量和系统校正,提高了测量精度。采用多次测量平均技术,提高了抗干扰能力和信噪比。用光耦合实现电气隔离,隔离部分用隔离式DC/DC供电,激励电流选为100μA,保证了被测者的安全。

Abstract:The aromaticity and condensational degree of coal macromloecular structure are studied through the correction for the presence of aliphatic side chains and hetero-atoms in coal rnacromolecule, which enables the coal structure to be considered as the purely hydro-aromatic hydrocarbon. The results agree with the properties of coal rnareomolecule.

Abstract:A procedure of fracture control blasting for achieving directional breaking of rocks by blasting is presented. The criterion for initiating of radial cracks in borehole wall under dynamic load and the method for determining the permissible rang of initial gas pressure (p0) in the charge cavity are developed .and the branching of radial cracks and the effeets of the pressure (p0) and blasthole geometry (R0.a.L3) on final dimensions of directed cracks are studied .with Fracture Mechanics analysis in all three aspects of fracture process including crack initiation .crack propagation and crack arrest.

Abstract:A Monte Carlo approach is appplied to the error estimation and error analysis of X-ray diffraction standardless quantitative phase analysis and the coefficient of its variation is cal dilated .which is compared with the error estimation by the condition number of the coefficient matrix of linear equations. The Monte Carlo error estimation is applied to the standardless quantitative matrix-flushing method, in which the mixture of KC1. CaCO3. ZnO and BaCO3 is analyzed as an example.

Abstract:The yandongkai' s 2-stories "v' shape sequence of natural number is generalized to 2-stories and n-stories "v" shape sequence of real number,and some very interesting properties are given.x

Abstract:The singular function is combined with Laplace' s transformation to calculate the deflection of stepwise beam. In this way the deflection equation of the beam is conveniently determined. This method is suited for both statically determinate and indeterminete stepwise beams and can simplify the calculation.

Abstract:Calculations and analyses are made with the CVDA, IIW, JWES standards for the strength and welding defects of two spherical tanks of natural gas in CHONG QING. The results of the analyses indecate that though there are some problems with the welding quality in these tanks, they may still be used with the desingned presure. Now the formal working of these two spherical thanks has verified of the validity the calculations and analyses.

Abstract:This paper introduces the method of extracting hespredin from fresh citrus peel, and states the extracting conditions in detail. Hesperidin is an improtant medical material. The firstrate hesperidin can be obtainted by using this method.