Let p is an element of (n/(n + 1), 1]. The authors investigate the (H-b(p)(R-n), L-p(R-n))-type and (H-b(p,infinity)(R-n), L-p,L-infinity(R-n))-type continuities for the maximal operators associated with the commutato...Let p is an element of (n/(n + 1), 1]. The authors investigate the (H-b(p)(R-n), L-p(R-n))-type and (H-b(p,infinity)(R-n), L-p,L-infinity(R-n))-type continuities for the maximal operators associated with the commutators of Bochner-Riesz operators with BMO(R-n) functions, where H-b(p)(R-n) and H-b(p,infinity)(R-n) are, respectively, the variants of the standard Hardy spaces and the standard weak Hardy spaces.展开更多
This paper establishes some strong type and weak type estimates for commutator [b,I1] on Herz-type spaces, where b E BMO(Rn) and I1 is a fractional integration with O < l < n.
Results of weakly commutative poe-semigroups are extended to Pseudo commutative po-semigroups. We prove that pseudo-commutative semigroups can bedecomposed into semilattices of Archimedean po-semigroups and such dec...Results of weakly commutative poe-semigroups are extended to Pseudo commutative po-semigroups. We prove that pseudo-commutative semigroups can bedecomposed into semilattices of Archimedean po-semigroups and such decomposition isnot unique.展开更多
We introduce the notion of weak k-hyponormality and polynomial hyponormality for commuting operator pairs on a Hilbert space and investigate their relationship with k-hyponormality and subnormality.We provide examples...We introduce the notion of weak k-hyponormality and polynomial hyponormality for commuting operator pairs on a Hilbert space and investigate their relationship with k-hyponormality and subnormality.We provide examples of 2-variable weighted shifts which are weakly 1-hyponormal but not hyponormal.By relating the weak k-hyponormality and k-hyponormality of a commuting operator pair to positivity of restriction of some linear functionals to corresponding cones of functions,we prove that there is an operator pair that is polynomially hyponormal but not 2-hyponormal,generalizing Curto and Putinar’s result(1991,1993)to the two-variable case.展开更多
引入拟正则Armendariz环并研究其性质。证明弱Armendariz环是拟正则Armendariz环,直积∏i∈I R i是拟正则Armendariz环当且仅当每个环R i(i∈I)是拟正则Armendariz环,同时证明R是拟正则Armendariz环当且仅当上三角矩阵环T n(R)(n≥2)是...引入拟正则Armendariz环并研究其性质。证明弱Armendariz环是拟正则Armendariz环,直积∏i∈I R i是拟正则Armendariz环当且仅当每个环R i(i∈I)是拟正则Armendariz环,同时证明R是拟正则Armendariz环当且仅当上三角矩阵环T n(R)(n≥2)是拟正则Armendariz环,并通过例子说明任意环R上的全矩阵环M n(R)(n≥2)不是拟正则Armendariz环。展开更多
当逆变侧交流系统发生故障引发换相失败时会导致送端母线出现过电压,特别是针对于弱送端交流电网,其过电压情形更加严重。提出了一种基于晶闸管全桥耗能子模块(thyristor full bridge power-consumption sub module,PCT-FBSM)的直流斩波...当逆变侧交流系统发生故障引发换相失败时会导致送端母线出现过电压,特别是针对于弱送端交流电网,其过电压情形更加严重。提出了一种基于晶闸管全桥耗能子模块(thyristor full bridge power-consumption sub module,PCT-FBSM)的直流斩波器(DC Chopper)拓扑结构,可以有效地抑制由换相失败引发的送端暂态过电压。文中首先分析了DC Chopper抑制过电压的机理,介绍了DC Chopper子模块的6种工作模式,然后设计了子模块在不同工况下的控制策略,并提出了子模块参数的设计方法,最后在PSCAD/EMTDC环境中搭建了相应的仿真模型,对所提拓扑结构对暂态过电压的抑制效果以及系统的运行特性进行了仿真分析,仿真结果表明所提DC Chopper可以有效抑制弱送端电网的暂态过电压。展开更多
基金Tang Lin and Yang Dachun are supported in part by the NNSF and the SEDF of China.
文摘Let p is an element of (n/(n + 1), 1]. The authors investigate the (H-b(p)(R-n), L-p(R-n))-type and (H-b(p,infinity)(R-n), L-p,L-infinity(R-n))-type continuities for the maximal operators associated with the commutators of Bochner-Riesz operators with BMO(R-n) functions, where H-b(p)(R-n) and H-b(p,infinity)(R-n) are, respectively, the variants of the standard Hardy spaces and the standard weak Hardy spaces.
文摘This paper establishes some strong type and weak type estimates for commutator [b,I1] on Herz-type spaces, where b E BMO(Rn) and I1 is a fractional integration with O < l < n.
文摘Results of weakly commutative poe-semigroups are extended to Pseudo commutative po-semigroups. We prove that pseudo-commutative semigroups can bedecomposed into semilattices of Archimedean po-semigroups and such decomposition isnot unique.
基金supported by National Natural Science Foundation of China(GrantNos.10801028 and 11271075)Science and Technology Development Planning Program of Jilin Province(GrantNo.201215008)Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20120043120003)
文摘We introduce the notion of weak k-hyponormality and polynomial hyponormality for commuting operator pairs on a Hilbert space and investigate their relationship with k-hyponormality and subnormality.We provide examples of 2-variable weighted shifts which are weakly 1-hyponormal but not hyponormal.By relating the weak k-hyponormality and k-hyponormality of a commuting operator pair to positivity of restriction of some linear functionals to corresponding cones of functions,we prove that there is an operator pair that is polynomially hyponormal but not 2-hyponormal,generalizing Curto and Putinar’s result(1991,1993)to the two-variable case.
文摘当逆变侧交流系统发生故障引发换相失败时会导致送端母线出现过电压,特别是针对于弱送端交流电网,其过电压情形更加严重。提出了一种基于晶闸管全桥耗能子模块(thyristor full bridge power-consumption sub module,PCT-FBSM)的直流斩波器(DC Chopper)拓扑结构,可以有效地抑制由换相失败引发的送端暂态过电压。文中首先分析了DC Chopper抑制过电压的机理,介绍了DC Chopper子模块的6种工作模式,然后设计了子模块在不同工况下的控制策略,并提出了子模块参数的设计方法,最后在PSCAD/EMTDC环境中搭建了相应的仿真模型,对所提拓扑结构对暂态过电压的抑制效果以及系统的运行特性进行了仿真分析,仿真结果表明所提DC Chopper可以有效抑制弱送端电网的暂态过电压。
