Unified physical and model representation of the magnetosensitive properties of bipolar transistor structures

The main physical mechanisms of operation of bipolar semiconductor transistor structures referred to as bipolar magnetosensitive structures (BMS) are analyzed. It is demonstrated that vertical magnetosensitive structures must be excluded from the BMS class, whereas horizontal structures form one class from the viewpoint of model representations irrespective of the direction of their magnetic axis. The mechanisms of BMS sensitivity in which the determining parameter is the mobility of carriers admit a common model representation and hence can be considered as a common redistribution mechanism. The BMS magnetic sensitivity, when estimating its conversion efficiency, is sufficiently correctly described by the one-dimensional continuity equation irrespective of the concrete boundary conditions. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 58–66, January, 2009.     

沿法线方向改进非DEA有效DMU

现有的非DEA有效DMU的改进方法造成DMU的投入或产出的波动太大,因而难以进行改进.提出了沿法线方向改进非DEA有效DMU的新方法.可以使非DEA有效DMU尽快到达有效前沿面,成为DEA有效,减小了波动幅度,并结合12所重点理工高校效评价的实际,验证了本方法的优势.     

Effect of high gamma dose on the PADC properties

The effect of the properties of PADC nuclear track detectors after exposure to high doses of gamma absorbed doses up to 5×10⁵ Gray (50 Mrad) were studied. The gamma source was a 9.03 PBq (244 KCi), Co-60 source. Results indicate that each of the bulk etch rate (V_b), the tracks etch rate (V_t) and the sensitivity (V) of the detectors increases with the high gamma absorbed dose, but there is a drop in these parameters at the low gamma absorbed dose. Signs of surface roughness were observed by increasing the gamma absorbed doses and changes in color observed for doses larger than 2×10⁵ Gray. The temperature of detectors during irradiation time reached 41°C. The fission fragment tracks (from Cf-252 source) disappeared quickly within the etching time (minutes) for total absorbed doses greater than 3×10⁵ Gray due to their high bulk etch rate.     

A Hydrocarbon-sensitized Argon Ionization Detector for the Detection of Inorganic Compunds

Noble gas ionization detectors make it possible to determine inorganie trace components in gases. Among the several modes of operation of these detectors the hydrocarbon-sensitized argon detector is a farourable compromise with regard to the relation of the expense to the attainable detection limit. The suitability of this detector for the determination of H₂, O₂, N₂, CH₄ and CO₂, in pure gases is shown.     

Bestimmung der Empfindlichkeit bei Tc-99-NMR-Messungen an einem 250-MHz-Spektrometer

By means of different concentrations the signal-to-noise ratios of Tc-99-NMR spectra were determined applying well measurable Tc-samples [tetrabutylammoniwn pertechnetate, TBA (TcO₄)J and a 250 MHz-spectrometer. The signal-to-noise ratios of the spectra were determined by using the integrated routines of the firm's software and accumulating different number of scans. By fittings of data of the signal-to-noise ratio dependence and by extrapolation the minimum Tc-concentralion could be empirically found out. Applying a duration of measurements of 12 hours about 10^?7 molar concentrations can be determined.     

Robust nonlinear optimization with conic representable uncertainty set

The robust optimization methodology is known as a popular method dealing with optimization problems with uncertain data and hard constraints. This methodology has been applied so far to various convex conic optimization problems where only their inequality constraints are subject to uncertainty. In this paper, the robust optimization methodology is applied to the general nonlinear programming (NLP) problem involving both uncertain inequality and equality constraints. The uncertainty set is defined by conic representable sets, the proposed uncertainty set is general enough to include many uncertainty sets, which have been used in literature, as special cases. The robust counterpart (RC) of the general NLP problem is approximated under this uncertainty set. It is shown that the resulting approximate RC of the general NLP problem is valid in a small neighborhood of the nominal value. Furthermore a rather general class of programming problems is posed that the robust counterparts of its problems can be derived exactly under the proposed uncertainty set. Our results show the applicability of robust optimization to a wider area of real applications and theoretical problems with more general uncertainty sets than those considered so far. The resulting robust counterparts which are traditional optimization problems make it possible to use existing algorithms of mathematical optimization to solve more complicated and general robust optimization problems.     

基于多项式混沌的全局敏感度分析

回顾基于多项式混沌和方差分解的全局敏感度分析方法,针对高维数随机空间和高阶多项式混沌展开面临的“维数灾难”问题,采用回归法、稀疏网格积分及基于l₁优化的稀疏重构技术（即压缩感知技术）来减少非嵌入式多项式混沌方法所需的样本配置点数目.针对几个典型响应面模型（包括Ishigami函数、Sobol函数、Corner peak函数和Morris函数）进行Sobol全局敏感度指标计算,展示多项式混沌方法在基于方差分解的全局敏感度分析中的有效性.     

Robust improvement schemes for road networks under demand uncertainty

This paper is concerned with development of improvement schemes for road networks under future travel demand uncertainty. Three optimization models, sensitivity-based, scenario-based and min–max, are proposed for determining robust optimal improvement schemes that make system performance insensitive to realizations of uncertain demands or allow the system to perform better against the worst-case demand scenario. Numerical examples and simulation tests are presented to demonstrate and validate the proposed models.     

金属纳米结构对光谱响应及折射率灵敏度的影响

推导了任意形状金属纳米结构对复杂环境折射率的局域表面等离子体共振(LSPR)光谱响应的解析解,给出了体折射率和局部折射率灵敏度公式,并进行了详细的理论分析和数值验证。结果表明,金属纳米结构的光谱响应与被分析物厚度呈指数增长关系,并与被分析物的折射率、敏感层厚度、金属纳米结构的材料和形状等因素有关。被分析物折射率越高,光谱响应越大。敏感层越厚,局部折射率灵敏度越差。同时,尖锐的金属纳米结构形状可以获得更大的体折射率灵敏度。对金属纳米结构光谱响应及折射率灵敏度的研究对制作高灵敏度LSPR传感器具有重要的指导意义。