阿基米德序半群的链的若干刻画

本文首先引入了一个序半群$S$的准素模糊理想的概念,通过序半群$S$上的一些二元关系以及它的理想的模糊根给出了该序半群是阿基米德序子半群的半格的一些刻画.进一步地借助于序半群$S$的模糊子集对该序半群是阿基米德序子半群的半格进行了刻画.尤其是通过序半群的模糊素根定理证明了序半群$S$是阿基米德序子半群的链当且仅当$S$是阿基米德序子半群的半格且$S$的所有弱完全素模糊理想关于模糊集的包含关系构成链.     

Ideals in the Roe Algebras of Discrete Metric Spaces with Coefficients in B（H）

The notion of an ideal family of weighted subspaces of a discrete metric space X with bounded geometry is introduced. It is shown that, if X has Yu＇s property A, the ideal structure of the Roe algebra of X with coefficients in B（H） is completely characterized by the ideal families of weighted subspaces of X, where B（H） denotes the C＊-algebra of bounded linear operators on a separable Hilbert space H.     

An Approximate Analytical Solution of Imploding Strong Shocks in a Non-Ideal Gas through Lie Group Analysis

The method of Lie group transformation is used to obtain an approximate analytical solution to the system of first-order quasilinear partial differential equations that govern a one-dimensional unsteady planer, cylindrically symmetric and spherically symmetric motion in a non-ideal gas, involving strong shock waves. Invariance groups admitted by the governing system of partial differential equations, which are indeed continuous group of transformations under which the system of partial differential equations remains invariant, are determined, and the complete Lie algebra of infinitesimal symmetries is established. The infinitesimal generators are used to construct the similarity variables. These similarity variables are used to reduce the governing system of partial differential equations into a system of ordinary differential equations.     

Effects of H on Electronic Structure and Ideal Tensile Strength of W: A First-Principles Calculation

We investigate the structure, energetics, and the ideal tensile strength of tungsten （W） with hydrogen （H） using a first-principles method. Both density of states （DOS） and the electron localization function （ELF） reveal the underlying physical mechanism that the tetrahedral interstitial H is the most energetically favorable. The firstprinciples computational tensile test （FPCTT） shows that the ideal tensile strength is 29.1 GPa at the strain of 14% along the [001] direction for the intrinsic W, while it decreases to 27.1 GPa at the strain of 12% when one impurity H atom is embedded into the bulk W. These results provide a useful reference to understand W as a plasma facing material in the nuclear fusion Tokamak.     

Rectifying and Photovoltage Properties of ZnO:Al/p-Si Heterojunction

An Al-doped ZnO/p-Si heterojunction is fabricated by a laser molecular beam epitaxy technique. The abnormally high ideality factors （n 〉〉 2） of the prepared heterojunction are observed in the interim bias voltage range. A theoretical model is proposed to understand the much higher ideality factor of the special heterojunction diode. The ZnO：Al film shows metal-like conductivity with the electrical resistivity about 6.56 × 10-4 Ω·cm at room temperature. The temperature dependence of the photovoltage indicates that the photovoltaic effect of the Al-doped ZnO based heterojunction can be changed by the intrinsic metal-semiconductor transition at 120 K.     

Electrical Characteristics of A1/CNT/NiPc/PEPC/Ag Surface-Type Cell

The blend of nickel phthalocyanine （NiPc） （2 wt. %） poly-N-epoxypropylcarbazole （PEPC）, （1 wt. %） and carbon nano-tube （CNT） powder （2 wt. %） in benzole is deposited by drop-casting on glass substrates with pre-deposited metallic electrodes to fabricate Ag/CNT/NiPc/PEPC/A1 surface type cell. It is assumed that the high nonlinearity of the I — V characteristics is related to deep traps in the nano-scale depletion region in NiPc that is observed experimentally. The values of ideality factor and barrier height are determined from the I — V curve and they are found to be 8.4 and 1.05eV, respectively. The values of mobility and conductivity are calculated to be 7.94 × 10？8 cm/Vs and 3.5 × 10？6 Ω？1 cm？1. The values of ideality factor and series resistance are also calculated by using Cheung＇s functions, which are in good agreement with the values calculated from the I — V curve.     

真实世界的近似图像——“拉普拉斯妖”随笔之四

一 物理学走过的路,往往是从一个理想模型开始的. 牛顿力学可以认为是近代物理学的一个起点,它的研究就是从一个最简单的理想模型--质点开始的.所以从某种意义上讲,近代物理的研究对象起源于一个点.这一事实蕴含着物理学一贯就有的重要研究方法,即对一个真实的系统建立一个与之相对应的理想模型,物理学家先通过对理想模型的探讨,寻找规律,建立理论,然后再去阐释真实世界中的事情.     

二元理想物系泡露点的简捷计算方法

提出了 2种计算二元理想物系的泡点和露点的简捷方法 ,通过实例说明计算过程 ,结果表明该方法收敛迅速 ,过程简单。     

平面光波导结构的FDTD分析

将各向异性理想匹配层(APML)吸收边界条件用于平面光波导结构的时域有限差分法(FDTD)分析中,导出了APML媒质中适用于角域和边缘的通用差分方程,并对平行介质带定向耦合器进行了数值模拟和验证,所得数值解与解析解非常一致.该方法可用于任意复杂结构的平面光波导的计算机辅助设计与分析.     

像增强器MTF测量理想像面选择方法研究

为了能够获得准确的调制传递函数测量结果,对测量系统中投射图像的理想成像面进行选择性调节。通过对微光像增强器调制传递函数测量系统光学成像性质的深入分析,讨论了光学系统的像差特性,利用平均中点取值法实现了微光像增强器调制传递函数测量中对理想成像面的选择。通过与微光像增强器已有测量结果的对比,证明所述方法能够保证微光像增强器调制传递函数测量的准确性。