分形粗糙面的电磁散射－扩展边界条件

用扩展边界条件方法对分形粗糙良导体面及介质面的电磁散射问题进行了分析。用推广的Floquet模式，在分界面处将场分量用Fourier级数展开，根据边界条件及扩展边界条件得到了水平极化和垂直极化散射场的幅度分量的表达式。用其它近似方法（Kirchhoff和Rayleigh方法）及能量守恒准则验证了此方法的有效性。     

短模型上的明渠非恒定流试验

水工整体模型试验中,明渠非恒定流至今大多被简化为恒定流,而效果有时并不理想。本文指出,只要设置固定式曲线尾门,并有必要的动态量测设备,便可模拟原型非恒定流;即使模型偏短,也能得出比恒定流试验更接近原型的成果。在同一模型上,既做恒定流试验,又进行必要的非恒定流试验,二者相辅相成,必将有助于试验水平的提高。作为例证,本文介绍了泄洪调度导致航道水面波动的一项试验成果,并以岩基冲刷、通航水流条件、围堰过水、河床冲淤等研究课题为例,讨论了采用“短模型非恒定流试验方式”的必要性与可行性。     

提高曲面近似展开精度的方法与实现

通过对不可展曲面近似展开精度的研究，提出了根据曲面曲率的大小对曲面自动进行网格划分，通过对综合展开误差数据场进行数据拟合来选取最优展开基点，基于空间曲面与其展开图间近似的等距变换关系进行展开样形的误差矫正等3种方法，这几种方法的实现在不同程度上有效地减小了曲面的近似展开误差，提高了曲面的近似展开精度。     

Signed line intercept count

Elements of surfaces that bound a phase (β) in a two phase mixture (α+β) may be classified as: (a) convex (++) if both principal curvatures are positive; (b) concave (? ?) if both are negative; and (c) saddle (+ ?) if one is positive and the other negative. This classification excludes the limiting cases for which one or both of the principal curvatures is zero. The traces of these surfaces that form the boundaries of the β areas on a representative two dimensional section may also be: (a) convex (+) if the local curvature is positive; or (b) concave (?) if it is negative. Line intercepts may be tabulated separately for intersections with convex (+) and concave (?) segments of boundary. This paper presents a derivation of fundamental stereological formulae that relate these counting measurements to three-dimensional geometric properties of the structure they sample.     

具有初曲率板弯曲的边界元分析

由于具有初曲率板弯曲问题的控制微分方程较复杂，直接求解原问题基本解推导边界积分方程较为困难。本文通过引入等效荷载，将此问题的控制微分方程化成与普通板弯曲基本方程形式相同的微分方程，利用一般求解板弯曲问题的边界元法迭代求解，建立了分析具有初曲率板弯曲问题的边界元法。算例表明本方法理论准确、精度良好。     

挡土墙填土曲线破裂面的地震主动土压力分析

在地震作用影响下，墙后填土处于极限平衡状态时，假定破裂面为一条通过墙趾的旋轮线。从墙后土楔中取出一微薄水平层，研究其在水平惯性力下的平衡，得到的地震土压力分布和土压力合力作用点位置均与实验结果相吻合。     

Adaptive generation of surfaces in volume data

A widespread approach to generating polygonal approximations of iso-surfaces or contour surfaces in volume data is the socalled marching-cubes algorithm. This algorithm, however, has the disadvantage that the number of polygonal chains generated is considerable. The splitting-box algorithm presented here reduces the number of polygonal chains by adapting their size to the shape of the surface. The resulting polygonal chains offer a wide spectrum for representing the contour surface. An exact representation is achieved by a new type of generic patches calculated from the polygonal chains. Approximations of different quality may be obtained by combining the algorithm generating the patches with simple triangulations.     

Some kinetic aspects of unsteady-state partial oxidation reactions. Dynamic processes on metal oxide surfaces

It is shown that steady-state kinetic data do not allow the discrimination between the redox and associated mechanisms of the partial oxidation reactions. A discrimination between these mechanisms was performed using transient experiments. The obtained rate expressions are in agreement with experimental kinetic data for catalytic partial oxidation of o-xylene.

An influence of the conjugate oxidation of a catalyst surface on dynamics and kinetics of the heterogeneous catalytic oxidative reactions is considered. Computing simulation of methane oxidative coupling of methane reaction at lowered temperature and elevated pressure has been performed. It showed that the reaction order with respect to oxygen exceeding unity is consistent with the chain branching mechanism of the reaction in the presence of TiSi₂ and TiB₂ and showed the important role of the branching chain cycles in the low-temperature OCM reaction at elevated pressure.     

Deformation analysis of skew ruled surface shells by moiré interference

The use of thin film grids coated on surfaces is described in relation to the determination of deformations in doubly curved shells. The technique is called the coating film moiré interference method and employs a laser holographic approach.     

Ecological aspects of the manufacture and application of highly pure liquid substances

The action mechanism for aggressive and highly pure media on fluoropolymer constructional elements is assumed to consist of two basic microeffects: destructive changes in the fluoropolymer and contamination of the environment. Our approach to a quantitative estimation of the physicochemical stability is based on logic similar to that of a thermodynamic model of a two‐component system. A fluoropolymer and changes in its microstructure are considered the first component of the system. The second component is composed of liquid media contaminated with fluoroorganic compounds extracted from the fluoropolymer. The proposed methods for delivering aggressive and highly pure fluids to consumers allow the exclusion of pollution from working areas with gaseous products through an exception to a number of intermediate stages of product transport. The discussed principles allow the creation of a modern, highly effective, and safe (with respect to the ecology and raw materials) production of aggressive liquid chemicals for consumers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 906–910, 2002