关于弱Hilbert性质的一个问题

本文证明了这样一个主要结果：设（Ｋ，Ｓ）和（Ｋ，Ｓ）都是亚序域，且（Ｋ，Ｓ）是（Ｋ，Ｓ）的有限生成扩张，则当Ｋ在Ｋ上是超越时，（Ｋ，Ｓ）具有弱Ｈｉｌｂｅｒｔ性质．这一结果否定地回答了作者在文献［１］中所提的一个公开问题．此外，一些关于弱Ｈｉｌｂｅｒｔ性质的结果被建立．     

二参数有限随机事件流

本文讨论二参数无后效有限随机事件流的鞅性和各种二参数Ｍａｒｋｏｖ性。     

Operators which have a closed quasi-nilpotent part

We find several conditions for the quasi-nilpotent part of a bounded operator acting on a Banach space to be closed. Most of these conditions are established for semi-Fredholm operators or, more generally, for operators which admit a generalized Kato decomposition. For these operators the property of having a closed quasi-nilpotent part is related to the so-called single valued extension property.

     

Monge properties,discrete convexity and applications

Starting from Monge’s mass transportation problem we review the role Monge properties play in optimization. In particular we discuss transportation problems whose cost functions fulfill a Monge property, Monge sequences, algebraic Monge properties, the recognition of permuted Monge arrays and multidimensional Monge arrays and the connections between Monge properties and discrete convexity. Finally we discuss Prékopa’s recent approach using Monge arrays in bounding multivariate probability distribution functions.     

On the pth moment exponential stability criteria of neutral stochastic functional differential equations

The paper discusses the pth moment exponential stability for a general class of neutral stochastic functional differential equations of the Ito type. This investigation can be very complicated, even in many special cases, by using usual methods based on Lyapunov functionals. In this paper we present criteria which are relatively easy to verify the pth moment exponential stability of the solutions of such equations.     

三项记忆梯度法及其投影算法的收敛性分析

对于无约束优化问题,提出了一类新的三项记忆梯度算法．这类算法是在参数满足某些假设的条件下,确定它的取值范围,从而保证三项记忆梯度方向是使目标函数充分下降的方向．在非单调步长搜索下讨论了算法的全局收敛性．为了得到具有更好收敛性质的算法,结合Solodov and Svaiter(2000)中的部分技巧,提出了一种新的记忆梯度投影算法,并证明了该算法在函数伪凸的情况下具有整体收敛性．     

Set-valued increasing-along-rays maps and well-posed set-valued star-shaped optimization

In this paper we introduce a class of set-valued increasing-along-rays maps and present some properties of set-valued increasing-along-rays maps. We show that the increasing-along-rays property of a set-valued map is close related to the corresponding set-valued star-shaped optimization. By means of increasing-along-rays property, we investigate stability and well-posedness of set-valued star-shaped optimization.     

Enhancement of magnetoresistances at room temperature in YSZ doping La0.67Sr0.33MnO3 system

The temperature dependence of the resistance of composite samples (1−x)La_0.67Sr_0.33MnO₃+xYSZ with different YSZ doping level x was investigated at magnetic fields 0-3 T, where YSZ represents yttria-stabilized zirconia. Results show that the YSZ dopant does not only adjust the metal-insulator transition temperature, but also increases the magnetoresistance effect. With increase of YSZ doping level for the range of x<2%, the metal-insulator transition temperature values T_P of the composites decrease, but T_P increases with increase of x further for the range of x>2%. Meanwhile, in the YSZ-doped composites, a broad metal-insulator transition temperature region was found at zero and low magnetic field, which results in an obvious enhanced magnetoresistance in the temperature range 10-350 K. Specially, a larger magnetoresistance value was observed at room temperature at 3 T, which is encouraging with regard to the potential application of magnetoresistance materials.     

间接驱动的冲击波特性实验

报道在星光激光器上进行的X光辐射驱动(间接驱动)和激光直接驱动的冲击波实验。实验观察到了铝背冲击波发光信息。结果表明,间接驱动比直接驱动的冲击波平面性好。     

On completely nonmeasurable unions

Assume that there is no quasi-measurable cardinal not greater than 2^ω . We show that for a c. c. c. σ -ideal 𝕀 with a Borel base of subsets of an uncountable Polish space, if 𝒜 is a point-finite family of subsets from 𝕀, then there is a subfamily of 𝒜 whose union is completely nonmeasurable, i.e. its intersection with every non-small Borel set does not belong to the σ -field generated by Borel sets and the ideal 𝕀. This result is a generalization of the Four Poles Theorem (see [1]) and a result from [3]. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)