Reliability consideration on a compound redundant system with repair

This paper considers a standby-redundant system consisting of 2 systems, in which one is main and the other is its standby-redundant system. These systems also consist of 2 subsystems connected in series.A feature of this system is that the system has 2 switching devices connecting subsystems, in addition to one connecting main and standby systems, in order to utilize surviving subsystem. In this consideration it is assumed that all the units are repairable.We shall obtain the system reliability, the mean time to system failure, the steady state availability, and examine numerically the effects of this model to the usual one without particular switching devices.     

Simulated annealing and its application to cobb-douglas economic model

Recently, the simulated annealing has been applied to several combinatorial optimization problems. In this paper, the simulated annealing method for continuous functions is reviewed, and it is applied to an economic model having multiple optimal solutions, in which all optimal solutions cannot be simultaneously obtained by Scarf's algorithm.     

Oxygen permeability of calcia-stabilized zirconia

Oxygen permeability of commercial calcia-stabilized zirconia has been measured at 1673 to 1823 K by the following cell; O₂ ZrO₂(CaO) N₂ - O₂ (P’tO₂ = 1 atm) solid electrolyte (P″O₂ = 0.39 - 10^10-3 atm). Oxygen permeability of calcia-stabilized zirconia is proportional to (1 - P″O₂ ^1/4). From the permeability measurement, the conduction properties of the electrolyte were log σ-_‡ ^b+ = 0.28- 5100/T and logP_b+ =-0.87 + 15,400/T where σ-_‡ ^b+ is the t-@#@ type electronic conductivity at P_{O 2} = 1 atm, and P_b+ is the oxygen activity at which the t-@#@ type electronic conductivity and the ionic conductivity are equal.     

Initial-value system for linear smoothing problems by covariance information

A Cauchy system suitable for real-time calculation of the solution of integral equations with semi-degenerate kernels of the linear least squares smoothing problems for nonstationary signal process is developed using invariant imbedding theory. Digital simulation results indicate that the algorithms presented are leasible.     

Microdetermination of bromide in water by gas chromatography

For the determination of micro order bromide in waters, a rapid, selective and sensitive method was studied. Bromide reacted with citric acid and potassium permanganate to form pentabromoacetone, which then turned into bromoform. The bromoform was measured by a head space gas chromatograph. The ion-exchange chromatograph (Amberlite CG-400, 10 mm i.d. × 70 mm; elutant, 0.1 M sodium nitrate, 70 ml and 0.5 M sodium nitrate, 25 ml) was applied to bromide without interfering substances such as chloride and phenols. Bromide of ppb levels in water can be accurately determined by ion-exchange chromatograph, potassium permanganate oxidation and head space gas chromatograph (ECD).     

用SPring-8同步辐射研究流体水银的结构变化和金属-非金属转变

随着从液态到气态的连续体积膨胀，在临界点附近，典型的液态金属水银经历了金属-非金属（M-NM）。在Spring-8的BL04B1高温高压实验站，利用同步辐射白光，采用能量色散X射线衍射（EDXD）方法，我们研究了流体水银从液体到稠密气态的宽广密度范围中的结构变化。实验方面，我们成功地开发出一个新的高压容器，它具有7个出射窗口用于收集散射X射线，测量的温度和压力上限分别是1700℃和2000bar，适合于在高温和高压下对流体物质进行能量色散X射线衍射测量。结果表明，流体水银的结构因子S(k)的精确性和可靠性有了很大的提高，并获得了流体水银的配位数和配位距离与密度变化之间的准确关系。我们发现，除了存在由配位数减少所导致的非均匀膨胀阶段之外，在水银的金属-非金属转变时还存在一新的均匀膨胀现象，即配位距离随密度减少呈线性增长阶段。基于这些新的结果，我们提出了流体水银的膨胀模型，并讨论了流体水银的金属-非金属转变与结构的关系。     

Effects of uni-axial mechanical stress on IGBT characteristics

This paper describes the impacts of mechanical stress on vertical power devices. The stress dependence of the DC characteristics of trench insulated gate bipolar transistors (IGBTs) was measured. The experimental results could be reproduced by the device simulation, which included stress dependence models of the carrier mobility and the band gap. We found that the stress dependence of the on-state voltage mainly arose from the MOSFET portion of the IGBT. Using the device simulation, we estimated the effects of mechanical stress on the surge voltage and the saturation current, which give us the important information for designing a power module with higher ruggedness.