Structures and stability of Al<Subscript><Emphasis Type="Bold">7</Emphasis></Subscript>C and Al<Subscript><Emphasis Type="Bold">7</Emphasis></Subscript>N clusters

We report results of the atomic and electronic structures of Al₇C cluster using ab initio molecular dynamics with ultrasoft pseudopotentials and generalized gradient approximation. The lowest energy structure is found to be the one in which carbon atom occupies an interstitial position in Al₇ cluster. The electronic structure shows that the recent observation [Chem. Phys. Lett. 316, 31 (2000)] of magic behavior of Al₇C^- cluster is due to a large highest occupied and lowest unoccupied molecular orbital (HOMO-LUMO) gap which makes Al₇C^- chemically inert. These results have further led us to the finding of a new neutral magic cluster Al₇N which has the same number of valence electrons as in Al₇C^- and a large HOMO-LUMO gap of 1.99 eV. Further, calculations have been carried out on (Al₇N)₂ to study interaction between magic clusters. Received 28 July 2001     

人参果引种高寒地区的试验研究

文章主要阐述了在引种人参果过程中的栽培管理技术措施和引种所取得的效果。     

基于RL&SM通用夹具系统的主动寻位技术及其实现方法

介绍了RL&SM通用夹具的寻位系统 ,描述了主动寻位与制造信息转换问题 ,提出和实现了相应的控制方法及其系统实现中的关键技术。理论分析与实验结果表明 ,提出的解决方法和技术是可行的 ,为RL&SM通用夹具系统的实际应用奠定了理论基础和技术支持     

The instability degree in the diemnsion of spaces of bivariate spline

In this paper, the dimension of the spaces of bivariate spline with degree less that 2r and smoothness order r on the Morgan-Scott triangulation is considered. The concept of the instability degree in the dimension of spaces of bivariate spline is presented. The results in the paper make us conjecture the instability degree in the dimension of spaces of bivariate spline is infinity.     

金属β-二酮化合物用于MOCVD法生长铁电氧化物薄膜

对用于MOCVD法生长铁电氧化物薄膜的金属β－二酮化合物的制备、结构及性质进行了评述，对它们在生长铁电薄膜中的应用现状进行了介绍，并对它们的应用前景作了展望。     

Solitary waves and their bifurcations of KdV like equation with higher order nonlinearity

We investigate the KdV like equation with higher order nonlinearity ut + a(1 +bun)unux + uxxx = 0with n ≥ 1, a, b ∈ R and α≠ 0. The bifurcations and explicit expressions of solitary wave solutions for theequation are discussed by using the bifurcation method and qualitative theory of dynamical systems. Thebifurcation diagrams, existence and number of the solitary waves are given.     

Can Millimeter Waves Generate Electroporation?

Analysis of the field distributions in a single biological cell under electromagnetic wave is given. With Debye approximation, the dielectric relaxation of each part of the cell, including the extracellular and cellular media, the cell membrane and the nuclear membrane, was taken into account. Making use of some typical parameters for a cell, the voltage across nuclear and cytoplasma membranes under electromagnetic waves are calculated up to millimeter wave frequency range. The calculated result indicates that it is unlikely to generate electroporation by present available millimeter wave sources.     

平果铝高压溶出过程结疤形成影响因素探索

平果铝高压溶出过程，结疤的形成是不可避免的，而且对生产带来的危害也很大。对结疤形成影响因素的研究，对于生产中结疤的治理，强化氧化铝生产具有十分重要的意义。     

Note on Bernstein polynomials and Kantorovich polynomials

We obtain two asymptotic representations of remainder of approximation of derivable functions by Bernstein polynomials and Kantorovich polynomials separately.     

The existence of Chern-Simons vortices

A new type of vortices called Chern-Simons vortices is considered and the existence is established.