Hilbert空间上的算子值(p,q)-Bessel乘子

在Hilbert空间上引入算子值p-框架和算子值(p,q)-Bessel乘子等概念,重点研究乘子,这里1<p,q<∞且1/p+1/q=1.一个算子值(p,q)-Bessel乘子是由一个算子值p-Bessel序列、一个算子值q-Bessel序列和一个有界数列构成.结果表明:(1)在一定条件下,有界数列分别属于c_(0),l^(1)和l^(2)时,乘子分别是紧算子、迹类算子和Hilbert-Schmidt算子;(2)当算子值q-Bessel序列换成p-Riesz基时,有界数列与乘子之间的对应是一对一的;(3)乘子关于其构成元具有连续依赖性.

{P,Q,k+1}-reflexive solutions to a system of matrix equations

In this paper,we investigate the{P,Q,k+1}-reflexive and anti-reflexive solutions to the system of matrix equations AX=C,XB=D and AXB=E.We present the necessary and sufficient conditions for the system men-tioned above to have the{P,Q,k+1}-reflexive and anti-reflexive solutions.We also obtain the expressions of such solutions to the system by the singular value decomposition.Moreover,we consider the least squares{P,Q,k+1}-reflexive and anti-reflexive solutions to the system.Finally,we give an algorithm to illustrate the results of this paper.

从一次试验谈如何使电梯安全钳更加安全

由某次电梯安全钳试验发现，目前安全钳在制造和选用时有P＋Q值选取过大的误区，这意味着制动时产生过大的制动力，危及乘客安全。因此必须控制有关安全钳的各种误差，适当降低安全钳制动力，同时在轿厢设计中也需有相应的应对策略。