二维整环的刻划

设R是整环,在本文中我们证明了R的弱整体维数不超过2当且仅当每一对w-模是平坦模,当且仅当每一有限型的w-模是投射模．     

Left almost split morphisms and generalized weyl algebras

It is proved that the category of modules of finite length over a broad class of generalized Weyl algebras contains no left almost split morphism starting from a simple module. It is shown that a similar assertion holds for the algebraUsl₂(k) over an algebraically closed field k of characteristic 0. As a by-product, a new series of simple modules for such algebras is constructed. Translated fromMatematicheskie Zametki, Vol. 66, No. 5 pp. 734–740, November, 1999.     

A Generalization of Auslander's Last Theorem

Before his death, Auslander announced that every finitely generated module over a local Gorenstein ring has a minimal Cohen–Macaulay approximation. Yoshimo extended Auslander's result to local Cohen–Macaulay rings admitting a dualizing module.Over a local Gorenstein ring the finitely generated maximal Cohen–Macaulay modules are the finitely generated Gorenstein projective modules so in fact Auslander's theorem says finitely generated modules over such rings have Gorenstein projective covers. We extend Auslander's theorem by proving that over a local Cohen–Macaulay ring admitting a dualizing module all finitely generated modules of finite G-dimension (in Auslander's sense) have a Gorenstein projective cover. Since all finitely generated modules over a Gorenstein ring have finite G-dimension, we recover Auslander's theorem when R is Gorenstein.     

Flat Modules over Group Rings of Finite Groups

Let k be a commutative ring of coefficients and G be a finite group. Does there exist a flat k G-module which is projective as a k-module but not as a k G-module? We relate this question to the question of existence of a k-module which is flat and periodic but not projective. For either question to have a positive answer, it is at least necessary to have |k| ≥ ?_ω. There can be no such example if k is Noetherian of finite Krull dimension, or if k is perfect.     

On nonsingular modules over infinite-dimensional simple novikov algebra of characteristic 0

In this paper we show that an A-module is a direct sum of a trivial module and a nosingular module, and we also give the structure of nonsingular module over infinite dimensional simple Novikov algebras of types (II) and (III) over a field F of Characteristic 0.     

液晶模块与背光源的频率干涉现象分析

从液晶模块的显示原理、驱动原理入手,阐述液晶模块的帧频率与光源频率叠加,从而产生频率干涉的现象,并给出了相应的解决方法。     

采用新型多层基板的多芯片组件封装技术

介绍了一种采用铜-聚酰亚胺薄膜多屡蒸板的多芯片组件（MCM）,它解决了高频下维持较低变调噪声带来的传输损耗增大,以及大量LSI芯片的同时切换噪声增大的问题。     

功放组件冷板的制造工艺

功放组件液冷方式主要通过组件冷板上布置的冷却液通道来实现.针对某雷达功放组件冷板的结构设计,详细阐述了工艺方案的选择对冷板材料和冷却液通道热加工方法的考虑,制定了冷板的制造工艺.     

通信用过流过压保护模块的工作机理分析

本文分析了通信用过流过压保护模块YD-CLP200M在过压保护、正浪涌和负浪涌过流保护模式下的工作原理,给出了与器件结构参数有关的内部等效电路.针对不同的器件结构参数,利用MEDICI器件模拟软件模拟了器件的开启电压、正浪涌开启电流的I-V特性曲线,模拟结果揭示了影响这些直流参数的主要因素,得到了优化直流特性所需的结构参数调整方法.     

Ideals of Finite-Dimensional Pointed Hopf Algebras of Rank One

Let H be a finite-dimensional pointed Hopf algebra of rank one over an algebraically closed field of characteristic zero.In this paper we show that any finite-dimensional indecomposable H-module is generated by one element.In particular,any indecomposable submodule of H under the adjoint action is generated by a special element of H.Using this result,we show that the Hopf algebra H is a principal ideal ring,i.e.,any two-sided ideal of H is generated by one element.As an application,we give explicitly the generators of ideals,primitive ideals,maximal ideals and completely prime ideals of the Taft algebras.