This article mainly discusses the direct sum decomposition of type G_2 Lie algebra, which, under such decomposition, is decomposed into a type A_1 simple Lie algebra and one of its modules. Four theorems are given to ...This article mainly discusses the direct sum decomposition of type G_2 Lie algebra, which, under such decomposition, is decomposed into a type A_1 simple Lie algebra and one of its modules. Four theorems are given to describe this module,which could be the direct sum of two or three irreducible modules, or the direct sum of weight modules and trivial modules, or the highest weight module.展开更多
Let R be a ring with an identity and C（R） be the category of right R-modules. In this paper we introduce the notion of semi-McCoy module. With this notion we show that McCoy modules of C（R） are closed under kernel...Let R be a ring with an identity and C（R） be the category of right R-modules. In this paper we introduce the notion of semi-McCoy module. With this notion we show that McCoy modules of C（R） are closed under kernels of epimorphisms, and they are also closed under extensions and direct sums with certain conditions. We also get some results on the subcategories of McCoy modules of C（R[x]） and C（R[x; x（-1）]）.展开更多
In this paper, we show that if C is a module with finite Goldie dimension, and A ＋ C≌B ＋ C, then there are essential submodules A＇△ A, B＇△ B such that A＇≌ B＇.
In this paper, we study modules having only finitely many submodules over any ring which is not necessarily commutative. We try to understand how such a module decomposes as a direct sum. We justify that any module V ...In this paper, we study modules having only finitely many submodules over any ring which is not necessarily commutative. We try to understand how such a module decomposes as a direct sum. We justify that any module V having only finitely many submodules over any ring A is an extension of a cyclic A-module by a finite A-module. Under some assumptions on A, such as commutativity of A, we prove that an A-module V has finitely many submodules if and only if V can be written as a direct sum of a cyclic A-module having only finitely many A-submodules and a finite A-module.展开更多
揭示一种新型多电平电压源换流器(voltage source converter,VSC),即模块化多电平VSC的起源与工作机制;介绍其子模块与VSC拓扑及相应工作原理;针对此新型换流器拓扑,并结合基于VSC的高压直流输电领域(high voltage direct current trans...揭示一种新型多电平电压源换流器(voltage source converter,VSC),即模块化多电平VSC的起源与工作机制;介绍其子模块与VSC拓扑及相应工作原理;针对此新型换流器拓扑,并结合基于VSC的高压直流输电领域(high voltage direct current transmission system based on VSC,VSC-HVDC),提出一种基于幂和理论的改进型多电平基频开关调制策略。与通常策略中所使用的数字迭代技术,如"牛顿-拉夫逊"法相比,该文所提算法可显著简化运算、降低计算量,且能求出开关角的所有解;而通常算法仅能求出单一解,忽略了可能存在的其他解,最后进行了仿真验证。理论分析与仿真结果均说明关于模块化多电平VSC本质揭示的正确性及所提调制策略的优越性。展开更多
基金The CLRPF(17pzxmyb10) of Guangdong Peizheng College
文摘This article mainly discusses the direct sum decomposition of type G_2 Lie algebra, which, under such decomposition, is decomposed into a type A_1 simple Lie algebra and one of its modules. Four theorems are given to describe this module,which could be the direct sum of two or three irreducible modules, or the direct sum of weight modules and trivial modules, or the highest weight module.
基金Supported by the National Natural Science Foundation of China(Grant No.11471017)the Natural Science Foundation of Anhui Higher Education Institutions of China(Grant No.KJ2018A0304)the Doctoral Research Foundation and the Research Culture Foundation of Anhui Normal University(Grant No.2014xmpy11)
文摘Let R be a ring with an identity and C（R） be the category of right R-modules. In this paper we introduce the notion of semi-McCoy module. With this notion we show that McCoy modules of C（R） are closed under kernels of epimorphisms, and they are also closed under extensions and direct sums with certain conditions. We also get some results on the subcategories of McCoy modules of C（R[x]） and C（R[x; x（-1）]）.
文摘In this paper, we show that if C is a module with finite Goldie dimension, and A ＋ C≌B ＋ C, then there are essential submodules A＇△ A, B＇△ B such that A＇≌ B＇.
文摘In this paper, we study modules having only finitely many submodules over any ring which is not necessarily commutative. We try to understand how such a module decomposes as a direct sum. We justify that any module V having only finitely many submodules over any ring A is an extension of a cyclic A-module by a finite A-module. Under some assumptions on A, such as commutativity of A, we prove that an A-module V has finitely many submodules if and only if V can be written as a direct sum of a cyclic A-module having only finitely many A-submodules and a finite A-module.
文摘揭示一种新型多电平电压源换流器(voltage source converter,VSC),即模块化多电平VSC的起源与工作机制;介绍其子模块与VSC拓扑及相应工作原理;针对此新型换流器拓扑,并结合基于VSC的高压直流输电领域(high voltage direct current transmission system based on VSC,VSC-HVDC),提出一种基于幂和理论的改进型多电平基频开关调制策略。与通常策略中所使用的数字迭代技术,如"牛顿-拉夫逊"法相比,该文所提算法可显著简化运算、降低计算量,且能求出开关角的所有解;而通常算法仅能求出单一解,忽略了可能存在的其他解,最后进行了仿真验证。理论分析与仿真结果均说明关于模块化多电平VSC本质揭示的正确性及所提调制策略的优越性。
