Determination of the coefficient of electron transmission using temperature measurements

The problem of determining the coefficient of electron transmission through the potential barrier at the metal-vacuum interface is considered. The temperature dependence of the thermofield’s current density is studied using methods of mathematical modeling. The problem is reduced to the solution of a system of algebraic equations. It is shown that regularization of the solution of the problem is required. The results demonstrate that the coefficient of electron transmission can be determined in principle.     

基于S3C2440的嵌入式多媒体控制器设计

根据当今移动终端设备多功能、低功耗、易于移植的要求,分别从硬件和软件系统2方面提出了一种基于三星S3C2440芯片的嵌入式多媒体娱乐控制器的解决方案,同时介绍了利用μCLinux构造嵌入式系统的方法,并提出了基于MiniGUI开发多媒体娱乐软件的基本方案。通过测试,系统能够满足用户在文字、音视频处理以及常用有线、无线数据交换等多方面的要求。     

Calculation of the crosstalk between Mach-Zehnder interferometers with traveling-wave electrodes

The crosstalk of electrodes on lithium niobate (LiNbO₃) Mach-Zehnder interferometers was studied. Three specific electrode configurations—Z-cut twin-electrode, Y-cut twin-electrode, and Y-cut tri-electrode—were analyzed. The capacitive coupling coefficient between electrodes was calculated by the method of moment and measured by an impedance analyzer. A scaled-up experimental setup was used to measure this coupling coefficient. The experimental data show good agreement with the numerical results. From the results, it was found that the coupling coefficient on Z-cut substrate with symmetric twin-electrode is larger than that of Y-cut substrate using twin- and tri-electrodes. In the case of asymmetric electrodes, however, the crosstalk between electrodes becomes smaller as the electrode width is increased.     

THE RELATION BETWEEN STRENGTH AND RIGIDITY OF BEAM1)

本文提出了梁的强刚比的定义,用无量纲的形式定量地表达了梁的强度与刚度之间的关系,以期充分发挥材料的潜力并促进材料力学的课堂教学。强刚比与载荷大小无关,其数值可以通过有限元方法或者通过梁的载荷试验来获得。结合工程实际,从设计和试验两个方面对梁的强刚比 及其影响因素进行了简要地探讨和分析。     

Effect of electron correlation in Kronig-Penney model

A one-dimensional model is proposed to investigate the symmetry-breaking-induced transition from the band limit to the atomic limit. The model calculation shows sharper transition for stronger intra-atomic correlation effect.     

Thermodynamic properties of a two-site Hubbard model with orbital degeneracy

Exact numerical solutions are obtained for a two-site doubly degenerate Hubbard model with 2, 3 or 4 electrons to study the effect of intra-atomic exchange interaction on the ground state and the thermodynamic properties. Some properties of macroscopic systems are reproduced qualitatively. The condition of having the Hamiltonian rotationally invariant in spin space gets important with increasing electron density.     

Influence of the image quality deterioration of a tilted thick specimen on electron tomography

In electron tomography (ET) based on a transmission electron microscope, the effective thickness of a specimen increases with the tilt angle and, therefore, the projection quality may deteriorate because of electron scattering. The information-missing region, however, can be reduced by broadening the specimen tilt range. To clarify the general influence of these effects on ET, the projection quality varying with the tilt angle was quantitatively evaluated for a 5-microm thick specimen observed with a 3 MV ultrahigh-voltage electron microscope. Simulations of three-dimensional reconstruction were then performed for different specimen thicknesses and tilt ranges. As a result, the ET accuracy was shown to decrease as the specimen thickness increased. However, an optimum specimen-tilt range, at which ET could reach its highest accuracy, was found to exist and become small with the increase of the specimen thickness. The presented results are helpful for determining the specimen thickness limitation on the ET resolution and improving the ET fidelity of thick specimens.     

Bayes Estimation of Reliability for Special k-out-of-m:G Systems

Component lifetimes of a k-out-of-m: G system are s-independent and exponentially distributed. The Bayes-quadratic-loss estimator of reliability for the system is obtained using a conjugate (1-parameter case) or a noninformative (2-parameter case) prior when data are type-II censored. A simple approximation formula for the mean square error of the Bayes estimator is proposed. Based on the mean square-error criterion, the performance of the Bayes estimator under a noninformative prior is compared with that of the maximum likelihood and minimum variance s-unbiased estimators.