UHF机械调谐器调谐电容片形的程序设计

采用传输线理论可以计算机械式UHF调谐器对应不同频率点的调谐电容量。在进行满足直线频率关系的调谐电容片形设计时,应当求出调谐电容量C_Τ与旋转角θ的显式函数关系。但对于分布参数的电路,这有一定的困难。本文采用数值计算方法完成了具有良好直线频率跟踪特性的调谐电容片形的设计,并由计算机自动绘出了片形。     

某些左零化子满足归纳条件的环

本文研究了某些特殊左零化子满足归纳条件的环的结构,得到:如果R是诣零环,P是使P半单环不含非零幂零理想的根性质,R为P根环的一个刻画。并对Goldie环的条件作了研究,得到了更一般的结果。     

MgCu4Sn型稀土镁合金相力学和热力学性质的第一性原理研究

采用基于密度泛函理论的第一性原理计算方法,系统研究了典型立方结构合金相LaMgX4(X=Co, Ni, Cu)的力学特性和热力学特性。根据广义胡可定律计算了合金相的单晶弹性常数;根据单晶弹性常数和Hershey’s averaging方法计算了合金相的多晶弹性模量、泊松比、Zener各向异性因子和德拜温度。采用基于准谐近似的Gibbs2代码计算了LaMgX4(X=Co, Ni, Cu)合金相的吉布斯自由能、熵和等体热容与温度的关系。LaMgNi4的计算结果与其他文献计算结果及实验结果符合的很好。结果表明：LaMgX4 (X= Co, Ni, Cu)合金均为延展性、塑性和弹性各向异性材料。德拜温度按以下顺序递减：LaMgNi4>LaMgCu4>LaMgCo4。     

Cr、Mn、Co、Ni掺杂对Al13Fe4相稳定性和力学性能影响的第一性原理研

采用基于密度泛函理论的第一性原理计算方法,系统地研究了不同掺杂浓度下过渡族元素Cr、Mn、Co、Ni在Al13Fe4相中的占位情况、结构稳定性和机械性能. 计算得到所有的Al13(Fe24-xMx) (M=Cr、Mn、Co、Ni;X=1,2,4)相都具有良好的热力学稳定性和机械稳定性. 相同掺杂浓度化合物的形成焓按如下顺序减小：Al78(Fe24-xCrx) > Al78(Fe24-xMnx) > Al13Fe4 > Al78(Fe24-xNix) > Al78(Fe24-xCox).形成焓的降低增加了Al13Fe4相成核驱动力,Co和Ni有利于促进Al-Fe合金中Al13Fe4相形核,细化Al13Fe4相. 过渡族元素可以改善金属间化合物的脆性,增强塑性变形能力. 并且随着掺杂浓度的增加,过渡族元素的加入对脆性的改善呈先增大后减小的趋势.     

On tolerance lattices of algebras in congruence modular varieties

We prove that the tolerance lattice TolA of an algebra A from a congruence modular variety V is 0-1 modular and satisfies the general disjointness property. If V is congruence distributive, then the lattice Tol A is pseudocomplemented. If V admits a majority term, then Tol A is 0-modular. This revised version was published online in June 2006 with corrections to the Cover Date.     

Approximating weak Chebyshev subspaces by Chebyshev subspaces

We examine to what extent finite-dimensional spaces defined on locally compact subsets of the line and possessing various weak Chebyshev properties (involving sign changes, zeros, alternation of best approximations, and peak points) can be uniformly approximated by a sequence of spaces having related properties.     

On the Pointwise Limit of Vector Charges with the Saks Property

The well-known theorem about the density of the space of probability charges with the Saks property in the space of all probability charges in the pointwise topology is proved in the vector case. New features are the uniform Saks property for the family of charges and sufficient conditions for the pointwise limit of a sequence of charges to have the Saks property.     

The Coordinatewise Uniformly Kadec–Klee Property in Some Banach Spaces

We introduce a new property UKK _c for a Banach space and show for an Orlicz sequence space the following: UKK _c H _{c 2}.     

On an Embedding Criterion for Interpolation Spaces and Application to Indefinite Spectral Problems

An embedding criterion for interpolation spaces is formulated and applied to the study of the Riesz basis property in the L _2,g space of eigenfunctions of an indefinite Sturm–Liouville problem u=gu on the interval (-1,1) with the Dirichlet boundary conditions, provided that the function g(x) changes sign at the origin. In particular, the basis property criterion is established for an odd g(x). Some connections with stability in interpolation scales are discussed.     

AFPP vs FPP

The main theme of this paper is that almost fixed point properties of discrete structures and fixed point properties of (topological) spaces are interdeducible via a suitable category which contains both graphs and spaces as objects. To carry out the program, we have to consider (almost) fixed points of multifunctions, and for this we need a preliminary discussion of power structures for graphs and simplicial complexes. Specific applications developed are: a digital convexity (discrete) version of Kakutani's fixed point theorem for convex-valued multifunctions; and fixed point properties of dendrites in terms of those of finite discrete trees.