An automatic class generation mechanism by using method integration

The paper presents a mechanism for automatically generating new classes from classes existing in a library by using their modification histories. To generate classes that are likely to meet a programmer's requirements and that are consistent with the existing classes, we propose three actors: a Specifier, a Finder, and an integrator. The Specifier records the history of modifications between methods with the same interface of a parent class and its heir. If the required method is not defined in the existing class which a programmer is referring to, the Finder retrieves classes similar to the referenced class and the Integrator applies the past modifications of similar classes to the referenced class. Classes are determined to be similar, based on their positions in a class hierarchy tree. Both the Specifier and Integrator are achieved by using a method integration algorithm based on object oriented bounded program slicing and class dependence graph matching. This mechanism enables programmers to reuse classes with little or no modification, and thus, easily create object oriented programs     

Ultrashallow junction formation by self-limiting LTP and its application to sub-65-nm node MOSFETs

We have developed a novel laser thermal process that dramatically enhances laser exposure windows by controlling the heating process in a self-limiting way. Key technology is realized by introducing a new process combination of preamorphization implantation and a heat absorber with a phase switch layer, and by optimizing them. The V/sub th/ rolloffs of MOSFETs formed by this method were remarkably improved compared to those by rapid thermal annealing when offset-spacer and halo-implantation processes were not applied. Its effectiveness was also verified in 50-nm gate complementary metal-oxide semiconductor devices for the first time by confirming that the drain current increased with laser fluence beyond the conventional exposure limit.     

InGaAs quantum dots formed in tetrahedral-shaped recesses on GaAs (111)B grown by metalorganic chemical vapor deposition

Novel semiconductor quantum dots (QDs), grown in tetrahedral-shaped recesses (TSRs) formed on a (111)B GaAs substrate, are described from both material science and device application points of view. After explaining the fabrication procedure for TSRs, growth of InGaAs QDs and their optical properties are explained. It is revealed that an InGaAs QD of indium-rich chemical composition is formed spontaneously at the bottom of each TSR. The mechanism of the QD formation is discussed in detail. It is proved from magneto-photoluminescence that the QDs actually have optical properties peculiar to zero-dimensional confinement. Several experimental results indicating excellent growth controllability of the QDs are presented. Finally, recent challenges to apply the QDs to electronic memory devices are reported. Two kinds of devices, where the position of individual QD is artificially controlled, are proposed for the first time and the preliminary experimental results are explained.     

硅橡胶表面分离水珠放电特性的研究

通过试品模拟试验研究了硅橡胶表面存在单个和多个水珠时的放电特性 ,分析了洁净硅橡胶表面凝结水珠时的闪络过程。结果表明 ,硅橡胶表面的分离水珠使水珠、硅橡胶和空气的三者交接处的场强加强 ,产生强烈局放以及间歇式的小电弧 ,水珠周围局部丧失憎水性和电场力的作用使水珠拉长 ,场强进一步加强发生闪络。     

A salient‐pole synchronous generator with permanent magnets between the field poles

In this paper, a new salient‐pole synchronous generator (SG) termed the PMa‐SG is presented. In the PMa‐SG, permanent magnets (PMs) are placed between the pole shoes to reduce the magnetic saturation in the field poles. By using finite element analysis (FEA), the internal magnetic fields and basic characteristics of a 2.8‐MVA PMa‐SG are compared with those of a conventional SG of the same size, and the reduction effect of the magnetic saturation of the PMs is examined. The FEA simulations are also validated by experiments on a 2.0‐kVA prototype machine. The PMs placed between the pole shoes reduce the magnetic saturation in the pole bodies and pole tips and effectively increase the terminal voltage and output power. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 174(4): 58–67, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21132     

Analysis of Eddy‐Current Losses in Solid Iron Under dc‐Biased Magnetization Considering Minor Hysteresis Loops

In designing solid‐pole synchronous machines, it is important to take into account the surface eddy‐current losses in the field pole cores. In this study, a solid‐iron ring specimen is adopted as an approximate model of solid‐pole surfaces in order to conduct a fundamental study of the surface losses. The influence of the minor hysteresis loops on the losses under dc‐biased magnetization is investigated. The losses in the ring under dc‐biased magnetization are measured and analyzed by finite element analysis (FEA). The losses computed by the FEA considering minor loops are nearly the same as those measured. In contrast, the eddy‐current losses computed by FEA without considering minor loops are considerably inaccurate because the incremental permeability is overestimated and the skin depth is underestimated. It is important to consider hysteresis for the accurate calculation of the surface eddy‐current losses under dc‐biased magnetization.     

Experimental and theoretical investigation of molecular diffusion coefficient of propylene in NMP

In this study, the absorption of propylene in N-methyl pyrolidone (NMP) was experimentally performed at three different temperatures (276.15, 293.15, and 328.15 K) using the pressure decay method and as a result, the equilibrium data, Henry's law constants, and kinetic data were reported. It was shown that the solubility and diffusivity are two important factors affecting the kinetic behavior of the system. This absorption system was mathematically modeled using Fick's second law accompanied by a time dependent boundary condition. An analytical method followed by numerical optimization was used to estimate the diffusion coefficient of propylene in NMP at different operating temperatures. The results demonstrated that the calculated diffusion coefficient obeys an Arrhenius type model. The resulting mathematical model was applied to calculate the number of absorbed moles of the gas. It shows a deviation of about 10% in comparison with the experimental measurements. Furthermore, the time dependent concentration profile along the liquid depth was also predicted.     

Functional Qbeta replicase genetically fusing essential subunits EF-Ts and EF-Tu with beta-subunit

Qbeta replicase, an RNA-dependent RNA polymerase of RNA coliphage Qbeta, is a heterotetramer composed of a phage-encoded beta-subunit and three host-encoded proteins: the ribosomal protein S1 (alpha-subunit), EF-Tu, and EF-Ts. Several purification methods for Qbeta replicase were described previously. However, in our efforts to improve the production of Qbeta replicase, a substantial amount of the beta-subunit overproduced in Escherichia coli cells was found as insoluble aggregates. In this paper, we describe two kinds of method of producing Qbeta replicase. In one kind, both EF-Tu and EF-Ts subunits were expressed with the beta-subunit, and in the other kind, the beta-subunit was genetically fused with EF-Tu and EF-Ts. The fused protein, a single-chain alpha-less Qbeta replicase, was mostly found in the soluble fraction and could be readily purified. These results pave the way for the large-scale production of the highly purified form of this enzyme.     

Synthesis and characterization of cobalt–nickel alloy nanowires

We report on the synthesis and magnetic characterization of ordered arrays of cobalt–nickel alloy nanowires. These alloy nanowires were electrodeposited into the pores of anodic alumina templates. The physical properties of the samples were investigated using scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, and vibrating sample magnetometer. We found that for the alloy nanowires the field at which the magnetization saturates increases with increasing Co fraction and the saturation field in the normal direction is smaller than the parallel direction, indicating easy magnetization direction normal to wire axis. Nanowires with different compositional ratio of cobalt and nickel showed a nonlinear dependence of coercivity as a function of cobalt concentration. These findings will help tailor magnetic nanoalloys with controlled properties for various applications, such as high density magnetic storage or nanoelectrode arrays.