武器装备测试性设计探讨

在研制武器装备时,要同时考虑装备的测试性设计和研制测试设备.针对现役武器系统测试性存在的问题,本文对测试性设计的必要性和测试性设计的方法等问题提出若干看法和设想.     

武器装备研制中测试性设计探讨

在研制武器装备时要同时考虑装备的测试性和研制测试设备。本文对现役武器系统测试性存在的问题,测试性设计的必要性,提高测试性的方法和在产品各个研制阶段测试性工作的进程等问题提出若干看法和设想。     

即时存在性和生长性在交互设计中的解读

目的提出并阐述即时存在性和生长性的概念并对二者特性进行解读。方法指出交互设计的根本要素是变动性,即时存在性和生长性是其外在的体现。分析了即时存在性和生长性的特性及其在交互设计中的价值,进而论述了两种特性的应用原则。结论即时存在性和生长性的应用有助于增强交互过程中的灵活性和创新性,增进用户与产品人机关系的和谐,这里旨在为交互设计的实现提供新的思路与方法。     

能力验证物品均匀性检验所用统计方法探讨

根据不同版本相关标准和指南对能力验证物品均匀性检验的规定和描述,辨析了相关统计方法的基本概念,探讨了能力验证物品均匀性检验的相关问题,对标准式指南中存在的问题进行了分析和说明。     

铌基合金的抗高温氧化性研究

综述了铌基合金抗高温氧化性研究的现状，并且对铌基合金抗高温氧化性研究的进展及存在的问题进行了阐述，提出了解决铌基合金抗高温氧化问题的可能途径。     

武器装备计量保障工作的分析

计量保障工作是武器装备研制生产过程中一项重要内容,本文从装备全寿命计量保障的角度,对武器装备计量保障工作存在的问题进行了分析,并从装备可测试性、可计量性设计等方面,提出了做好武器装备计量保障工作的方法和建议.     

座椅的热舒适性及其评价方法的探讨

文章分析了座椅温湿度条件对人体舒适性的影响,阐述了座椅材料的导热性、透湿性和透气性等热舒适性能及国内外相关研究进展,概述了座椅热舒适性的几种评价方法,提出了座椅热舒适性研究方面存在的问题和展望。     

浅谈我国动物源性食品安全现状及对策分析

近些年,食品安全问题备受关注,其中动物源性食品的质量与安全尤为重要。论文首先分析了当前我国动物源性食品安全现状,结果令人堪忧,并针对存在问题提出相应的解决措施,提出了符合国际标准的动物源性食品原料供应、生产加工、企业管理和政府监管模式,以解决动物源性食品安全问题,提高动物源性食品质量。     

广义二阶不变凸向量变分类不等式

研究了广义二阶不变凸向量变分类不等式问题解的存在性，并讨论其与多目标优化问题解之间的关系。引入了两种广义二阶不变凸函数和一种广义二阶单调函数，并给出具体实例说明了它们的存在性。在广义二阶不变凸性假设下，利用分析的方法给出了向量变分类不等式与多目标优化问题解之间的关系。利用KKM定理，在广义二阶单调性假设下得到了向量变分类不等式问题解的存在性定理。研究表明在广义二阶单调性假设下，向量变分类不等式存在解，并且在适当的广义二阶凸性条件下，其解与多目标优化问题解之间相互等价。     

一类伪抛物型方程初边值问题

本文讨论和一些重要的物理过程有着密切关系的一类伪抛物方程的初边值问题。首先利用强制不等式和连续性方法推广了现有的线性问题解的存在惟一性结果,然后利用Hilbert空间中Leray-Schauder度的同伦不变性,给出了一类非线性伪抛物方程解的存在性定理。     

Fano effect for pairs of impurity ions in solids

The existence of a Fano effect in optical transitions of pairs of dissimilar ions solids is discussed. The use of Fano's formalism for such pairs is justified on the basis of a simplified model of the pairs, and the relationships between his notation and that of the model system are derived. Possible forms for the excitation profile are presented for a more complex model in which at least one ion has a state intermediate in energy between the ground state and the excited state involved in the Fano effect. In this case the lineshape function for excitation of the coupled antiresonant spectral range is not necessarily the same as that for absorption. Inconclusive results of attempts to observe an antiresonance in the spectra of Cr³⁺-Nd³⁺ pairs in several laser host crystals are summarized, and used to suggest constraints which restrict candidate systems for further experimental investigations.     

Ultracold Fermi Gases : The BEC-BCS Crossover

We give an introduction to the present state of research in the field of ultracold atomic Fermi gases. Of particular interest is the search for (BCS) superfluidity in these systems. The existence of Feshbach resonance have made these systems especially flexible, allowing to control at will the strength and the sign of the effective interaction. In particular it has allowed an experimental realization of the Bose-Einstein Condensation (BEC)-BCS crossover allowing to display on one side a Bose condensate of molecules and on the other side a BCS superfluid produced by Cooper pairs. Then we focus more specifically to the shift of the molecular threshold, produced by Pauli exclusion in these degenerate gas. We discuss also briefly collective modes corresponding to oscillations of the gas in the harmonic trap in which it is confined.      

Vortex dynamics and decay of supercurrent in 2-d superconductors

The decay of supercurrent in a 2-d superconductor through the homogenous quantum nucleation of vortex-antivortex pairs is formulated as a (2+1)-d scalar quantum electrodynamic problem. The calculation of the quantum decay rate can then be simplified to the usual single particle WKB calculation. We show explicitly that the homogeneous quantum nucleation of vortex-antivortex pairs is incompatible to the existence of the magnus force in the absence of dissipation, and point out more complicated nucleation processes needed to be studied by the vortex dynamics method in such case.     

椭圆型方程的一种新型混合有限元格式

基于实际问题对通量较低的正则性要求,本文建立了椭圆型方程的一种新型混合变分形式.在鞍点问题框架下,通过验证LBB条件,证明了该混合形式解的存在唯一性.由于压力空间不再是传统的H(div),而是平方可积空间,因此混合元的选取变得简单容易.同时本文给出了相应的有限元逼近形式,并对于由分片常数速度元和分片线性压力元构成的协调...     

整车悬架的最优模糊半主动控制

以配置四个磁流变阻尼器的整车悬架为控制对象,提出顶层最优控制与底层模糊控制相结合的最优模糊控制思想。首先由整车悬架随机最优控制获得4对期望的控制力,再通过模糊控制器使各磁流变阻尼器的反力逼近这4对控制力,从而实现对整车悬架的振动半主动控制。仿真研究表明,最优模糊控制的控制效果明显优于现有的开关最优控制,特别是对簧载质量的垂直加速度、俯仰角加速度以及悬架动挠度抑制效果明显,可不同程度改善车辆的行驶平顺性和操纵稳定性。     

Primitive elements in finite fields and costas arrays

In [7] Golomb made four conjectures concerning the existence of pairs of primitive elements in finite fields. In this note we resolve each of the conjectures in the affirmative. As a consequence several conjectured classes of Costas arrays do indeed exist.This author would like to thank the National Security Agency for partial support under grant agreement #MDA904-87-H-2023     

Cr-Tm ion pairs in Gd3Ga5O12 garnet

A study is presented about Cr³⁺→Tm³⁺ energy transfers in Gd₃Ga₅O₁₂ garnet at 10 K. By time-resolved spectroscopy and analysis of decay kinetics we determine the nature of the interaction and we show the existence of chromium-thulium pairs in which the chromium emission wavelength is shifted from 693.6 to 694 nm.     

Two-dimensional solitons in a Kerr cavity

Abstract

We study the existence and nature of soliton-like localized states in a passive cavity containing a Kerr medium driven by a plane-wave input field. As the background intensity is increased, these structures are always created in pairs, for topological reasons. The smaller ‘soliton’ is always unstable, while in two transverse dimensions the larger ‘soliton’ usually collapses to a singularity or decays.     

正则周期矩阵对分离度的估计

正则周期矩阵对在分析和设计线性离散周期控制系统中有重要应用．正则周期矩阵对的分离度是测量周期矩阵对的周期收缩子空间敏感性的一个重要指标,因此,计算这个分离度显得非常重要．然而,这需要的太多的计算量．目前对单个矩阵和矩阵对的分离度的估计,常用的处理方法有二种：一种是利用矩阵的Schur分解,另一种则是利用矩阵的约当分解．本文应用正则周期矩阵对的周期Schur分解,给出这个分离度的上界和下界．这与计算精确的分离度相比较可大大减少运算量．另外,这些界可以看成是两正则矩阵对分离度的上、下界的推广．最后,数值例子验证了所给的下界和上界．     

Quantum confinement effects in chemically grown,stable ZnSe nanoclusters

Stable ZnSe quantum dots have been prepared by a wet chemical route. Sodium Hexameta Phosphate, an inorganic polymer, is used to encapsulate the ZnSe quantum dots and to enhance the stability of quantum dots. X-ray Photoelectron Spectroscopic analysis confirms the high purity of ZnSe clusters. The optical absorption spectra exhibit a blue shift of about 0.6 eV, suggesting the existence of quantum size effects. Room temperature photoluminescence measurements show a strong feature which originates from the radiative recombination of the quantum confined electron-hole pairs.