Software quality improvement: a model based on managing factors impacting software quality

Software quality is recognized as being very significant for achieving competitiveness in the software industry, so improvements in this area are gaining increasing importance. Software quality improvements can only be achieved by managing all of the factors that influence it. However, in a real business system, there are a great number of factors impacting software quality, while the processes are stochastic and resources are limited, so economic data should also be taken into consideration. This paper uses a Markov chain and proposes a systematic framework for modelling the stochastic processes of a quality management system and selection of the optimum set of factors impacting software quality. A methodology is presented for managing the factors that affect software quality with an illustrative hypothetical example for convenience of application of the proposed methodology.     

Highly efficient Raman frequency converter with strontium tungstate crystal

A highly efficient extracavity Raman laser pumped by the infrared nanosecond laser pulses is presented utilizing the recently recommended Raman medium-strontium tungstate crystal (SrWO/sub 4/). The maximum conversion efficiency of the first and second Stokes pulses both reached about 50%, and the maximum total conversion efficiency of the first and second Stokes was obtained to be 70% in the experiment. The conversion efficiency dependence on the polarization and the temporal characteristics of the Stokes and pump pulses were also studied. A theoretical model for the solid-state extracavity Raman laser was established based on the radiation transfer equations describing stimulated Raman scattering processes, and solved numerically. This model can accurately predict the energy transfer dynamics observed in extracavity Raman lasers.     

Theoretical and experimental study on the self-Raman laser with Nd:YVO/sub 4/ crystal

The intracavity photon densities and the initial population inversion density were assumed to be Gaussian distributions in the rate equations of the laser diode end-pumped actively Q-switched intracavity Raman laser. These space-dependent rate equations were solved numerically. In the experiment, an efficient self-Raman laser was realized based on the multifunctional Nd:YVO/sub 4/ laser crystal with the acoustooptic Q-switch. The output, temporal, and spectral characteristics of the self-Raman laser were investigated experimentally in detail. The performance of the self-Raman laser was studied numerically, and the theoretical results showed the main trends of the intracavity Raman laser, which are in agreement with the experimental ones.     

基于知识的故障诊断模型研究

本文在各种诊断方法研究的基础上,结合诊断对象的各种知识,构造基于知识的分层混合推理诊断模型,给出模型中面向对象的知识表示方法及混合推理机制.该模型能有效的利用诊断信息,在理论和方法上为诊断系统的开发提供了有益的参考.     

Merging Nanowires and Formation Dynamics of Bottom-Up Grown InSb Nanoflakes

Indium Antimonide (InSb) is a semiconductor material with unique properties, that are suitable for studying new quantum phenomena in hybrid semiconductor-superconductor devices. The realization of such devices with defect-free InSb thin films is challenging, since InSb has a large lattice mismatch with most common insulating substrates. Here, the controlled synthesis of free-standing 2D InSb nanostructures, termed as “nanoflakes”, on a highly mismatched substrate is presented. The nanoflakes originate from the merging of pairs of InSb nanowires grown in V-groove incisions, each from a slanted and opposing {111}B facet. The relative orientation of the two nanowires within a pair, governs the nanoflake morphologies, exhibiting three distinct ones related to different grain boundary arrangements: no boundary (type-I), Σ3- (type-II), and Σ9-boundary (type-III). Low-temperature transport measurements indicate that type-III nanoflakes are of a relatively lower quality compared to type-I and type-II, based on field-effect mobility. Moreover, type-III nanoflakes exhibit a conductance dip attributed to an energy barrier pertaining to the Σ9-boundary. Type-I and type-II nanoflakes exhibit promising transport properties, suitable for quantum devices. This platform hosting nanoflakes next to nanowires and nanowire networks can be used to selectively deposit the superconductor by inter-shadowing, yielding InSb-superconductor hybrid devices with minimal post-fabrication steps.     

基于t-SNE的脑网络状态观测矩阵降维方法研究

针对基于功能核磁共振重构的脑网络状态观测矩阵维数过高和无特征的特点,对其降维方法展开研究,给出了基于t-SNE的脑网络状态观测矩阵降维算法,并且利用Python实现了降维及可视化平台。实验结果表明,与目前主流的其他降维算法相比较,使用该方法得到的脑网络状态观测矩阵低维空间的映射点有明显的聚类表现,并且在多个样本上的降维结果显现出一定的规律性,从而证明了该算法的有效性和普适性。     

WS-BPEL Extensions for Versioning

This article proposes specific extensions for WS-BPEL (Business Process Execution Language) to support versioning of processes and partner links. It introduces new activities and extends existing activities, including partner links, invoke, receive, import, and onmessage activities. It proposes version-related extensions to variables and introduces version handlers. The proposed extensions represent a complete solution for process-level and scope-level versioning at development, deployment, and run-time. It also provides means to version applications that consist of several BPEL processes, and to put temporal constraints on versions. The proposed approach has been tested in real-world environment. It solves major challenges in BPEL versioning.     

Actinide reformer concept

The partitioning and transmutation technology is effective to reduce the environmental impact from disposition of high-level radioactive wastes and improve the efficiency of geological disposal. However, Am and Cm and their daughter nuclides are difficult to handle in the fuel cycle because of their high decay heat and radioactivity. These nuclides also give the chemical instability which harms the soundness of fuel pellet properties.

We propose a new system concept “actinide reformer”, which reforms Am and Cm into Pu by neutron capture reactions and decay. Am and Cm are separated from the PUREX reprocessing process and converted to chloride molten-salt fuel. Using liquid-type fuel, above mentioned defects can be compensated. Actinide reformer is an accelerator-driven system which is composed of a 10 MW-class cyclotron, a tungsten target and a subcritical core. Spent molten-salt fuel is reprocessed as an on-line fuel exchange manner to extract fission products and recover Pu to send back to a power generation cycle. The decay heat and neutron emission from the fuel with recovered Pu are smaller than those of MOX fuel with 5% of minor actinide addition. It expects no significant engineering difficulties and cost increase for construction of MOX fuel based reprocessing/fabrication plant and power reactors.     

多孔SiO2凝胶玻璃的制备及孔径控制

以正硅酸乙酯（ＴＥＯＳ）为原料，采用溶胶－凝胶法制备了多孔ＳｉＯ２凝胶玻璃，研究了氨水，盐酸，硝酸，氢氟酸等不同种类的催化剂对孔的影响，制备了多孔ＳｉＯ２凝胶玻璃，利用氮气吸附法对孔结构进行了分析。在透射电镜下观察了凝胶颗粒形貌。     

Current-gain cutoff frequency comparison of InGaAs HEMTs

The current-gain cutoff frequency performance of pseudomorphic InGaAs/AlGaAs (20% InAs composition) high-electron-mobility transistors (HEMTs) on GaAs is compared to that of lattice-matched InGaAs/InAlAs HEMTs on InP. The current-gain cutoff frequency (f_t) characteristics as a function of gate length (L_g) indicate that the f_t-L_g product of ~26 GHz-μm in InGaAs/InAlAs HEMTs is 23% higher than that of ~21 GHz-μm in InGaAs/AlGaAs HEMTs. The performance of InGaAs/AlGaAs HEMTs is also 46% higher than that of conventional GaAs/AlGaAs HEMTs (~18 GHz-μm). These data are very useful in improving the device performance of HEMTs for a given gate length