Spatially Homogeneous Bianchi Type V Cosmological Model in the Scale-Covariant Theory of Gravitation

We discuss spatially homogeneous and anisotropic Bianchi type-V spacetime filled with a perfect fluid in the framework of the seale-covariant theory of gravitation proposed by Canuto et al. By applying the law of variation for Hubble＇s parameter, exact solutions of the field equations are obtained, which correspond to the model of the universe having a big-bang type singularity at the initial time t = 0. The cosmological model, evolving from the initial singularity, expands with power-law expansion and gives essentially an empty space for a large time. The physical and dynamical properties of the model are also discussed.     

一类分数次积分算子在Herz型Hardy空间上的有界性

通过放宽尺寸条件,得到了一类具有分数次积分性质的次线性算子从Herz型Hardy空间到(弱)Herz型Hardy空间有界性的判定条件,以及端点处的弱型估计.     

Banach空间中具有数列的渐近拟非扩张型映象的不动点及其具有误差的Ishikawa迭代逼近

1引言及相关定义 引文[1～5]讨论了渐近非扩张映象和渐近非扩张型映象不动点的迭代逼近问题.文[6]改进了文[1]中条件,将T由渐近非扩张型映象推广到T是渐近拟非扩张型映象.     

Littlewood-Paley算子交换子在加权Herz型Hardy空间上的有界性

研究了Littlewood-Paley算子交换子gψ,b在加权Herz型Hardy空间上的性质,并证明了gψ,b在某些条件下是HKa,pq(ω1,ω2)到Ka,pq(ω1,ω2)和HKa,pq(ω1,ω2)到WKa,pq(ω1,ω2)上的有界算子.     

群体决策随机偏爱数映射的若干性质

1引言近年来,群体决策在社会选择、福利、经济和军事等领域得到广泛应用,从而其理论研究越来越被人们所重视.20世纪中叶,K.J,Arrow提出了偏爱公理系和不可能性定理,并     

Some remarks on pseudo-umbilical totally real submanifolds in a complex projective space

This paper studies the relationship between the pseudo-umbilical totally real submanifolds and the minimal totally real submanifolds in a complex projective space. Two theo- rems which claim that some types of pseudo-umbilical totally real submanifolds must be minimal submanifolds are proved.     

半空间几何中含参数的抽象动力方程边值问题

本文在一般Banach空间中取值的向量值函数组成的Lebesgue空间中，用算子半群方法，研究了半空间几何中含参数的抽象动力方程边值问题的解．     

Morgan-Scott剖分上样条空间S_8~4(Δ_(ms))的维数

Ｍｏｒｇｅｎ－Ｓｃｏｔ剖分上样条空间的维数依赖于剖分的几何性质，本文证明了Ｄｉｅｎｅｒ１９９０年提出的猜想对ｒ＝４是不正确的，需要修正．     

基于LabVIEW的空间相机试验测控系统设计

在LabVIEW开发环境下,基于虚拟仪器和PXI总线,采用National Instrument(NI)公司的数据采集卡,设计了一个空间相机试验测控系统,实现了硬件设计和软件功能。该系统具有多个通道,可测试温度、应力、应变等多种参数,能实现测控参数设置、数据采集与处理、数据及曲线显示、信号分析与处理、远程通信等多种功能。在某空间相机分系统热平衡试验中,用于测试、控制36个热敏电阻测温点和14个热电偶测温点的温度。结果表明,系统达到了0.5℃的控温要求;热电偶的标定和标准水银温度计的比对结果表明,本系统测温精度可达到0.15℃。与传统的文本语言相比,利用LabVIEW节省了大约80%的时间。本系统具有延续开发能力和可移植性,其设计方法能为其它测控系统的开发提供参考。     

Terahertz Quantum Cascade Laser Operating at 2.94THz

The development of quantum cascade laser at 2.94 THz is reported. The laser structure is based on a bound-to-continuum active region and a semi-insulating surface-plasmon waveguide. Lasing is observed up to a heat-sink temperature of 70 K in pulsed mode with light power of 4.75 mW at 10 K and 1 mW at 70 K. A threshold current density of 296.5 A/cm2 and an internal quantum efficiency of 1.57 × 10-2 per cascade period are also observed at 10 K. The characteristic temperature of this laser is extracted to be T0 = 57.5 K.