Reliability-estimation and stopping-rules for software testing,based on repeated appearances of bugs

Software-testing (debugging) is one of the most important components in software development. An important question in the debugging process is, when to stop. The choice is usually based on one of two decision criteria: (1) when the reliability has reached a given threshold, and (2) when the gain in reliability cannot justify the testing cost. Various stopping rules and software reliability models are compared by their ability to deal with these two criteria. Two new stopping rules, initiated by theoretical study of the optimal stopping rule based on cost, are more stable than other rules for a large variety of bug structures. The 1-step-ahead stopping rules based on the Musa et. al. basic execution and logarithmic Poisson models, as well as the stopping rule by Dalal and Mallows (1990), work well for software with many relatively small bugs (bugs with very low occurrence rates). The comparison was done by simulation     

BID: a novel BH3 domain-only death agonist

The BCL-2 family of proteins consists of both antagonists (e.g., BCL-2) and agonists (e.g., BAX) that regulate apoptosis and compete through dimerization. The BH1 and BH2 domains of BCL-2 are required to heterodimerize with BAX and to repress cell death; conversely, the BH3 domain of BAX is required to heterodimerize with BCL-2 and to promote cell death. To extend this pathway, we used interactive cloning to identify Bid, which encodes a novel death agonist that heterodimerizes with either agonists (BAX) or antagonists (BCL-2). BID possesses only the BH3 domain, lacks a carboxy-terminal signal-anchor segment, and is found in both cytosolic and membrane locations. BID counters the protective effect of BCL-2. Moreover, expression of BID, without another death stimulus, induces ICE-like proteases and apoptosis. Mutagenesis revealed that an intact BH3 domain of BID was required to bind the BH1 domain of either BCL-2 or BAX. A BH3 mutant of BID that still heterodimerized with BCL-2 failed to promote apoptosis, dissociating these activities. In contrast, the only BID BH3 mutant that retained death promoting activity interacted with BAX, but not BCL-2. This BH3-only molecule supports BH3 as a death domain and favors a model in which BID represents a death ligand for the membrane-bound receptor BAX.     

Laser welding of Al55-Zn coated steel sheet

A study has been made of the procedures used for the lap and butt welding of 0.62 and 1.16 mm thickness steel sheets coated with Al55-Zn alloy, using laser-beam technology. The main problems arise in lap welding as a result of zinc evaporation from the coating. The vapour pressures of this element lead to cratering and blistering of the welds which are visible from the external surface and imply severe weld defects. An efficient solution to this problem consists in leaving a gap between the internal faces, thus allowing the zinc vapours to escape. Excessive gaps, however, lead to the molten metal collapse and to lack of penetration. In the present work, acceptable results were obtained with a maximum interface separation of 0.1 mm. This allows excellent continuity of the joints, without cracks, pores or non-metallic inclusions and with moderate hardnesses, thus demonstrating the good laser weldability of the coated material. A difficulty arises, however, in relation to the coating in zones close to the weld. In these high-temperature zones the coating is lost, and in the immediately adjacent areas the coating microstructure and phases are altered, as was shown by scanning electron microscope analyses.     

对我国催化重整工艺专利市场的思考

根据我国专利法的原则，在对我国催化重整和芳烃生产专利检索过程和结果进行分析的基础上，阐述了对目前我国催化重整工艺专利市场的几点看法并提出对策。     

Requirement of cysteine-rich repeats of the Fas receptor for binding by the Fas ligand

The Fas receptor is a member of a family of cell death receptors, including tumor necrosis factor receptor I (TNFR I), death receptor 3 and 4 (DR3 and DR4), and cytopathic avian receptor 1 (CAR1). The Fas receptor is composed of several discrete domains, including three cysteine-rich domains (CRDs), a transmembrane domain, and an intracellular domain responsible for transmitting an apoptotic signal. While the mechanism of Fas-mediated cell death has become elucidated, the requirements for Fas ligand binding to the receptor have not been fully defined. Using a series of chimeric Fc-receptor fusion proteins between the human Fas receptor and TNFR I, each cysteine-rich domain of Fas was found to be required for interaction with the Fas ligand. Interestingly, TNFR I CRD1 could partially substitute for the Fas CRD1. The importance of this domain was underscored by the analysis of a Fas extracellular mutation (C66R), which resulted in a complete loss of ligand binding. This mutation was cloned from a human patient suffering from Canale-Smith syndrome, which is characterized by autoimmunity resembling that observed in the lpr and lprcg mice. The localization of essential ligand binding domains in the Fas receptor correlated exactly with the ability of the Fas receptor fusion proteins to prevent cell death mediated by the Fas ligand.     

An extraction method to determine interconnect parasitic parameters

Interconnect parasitic parameters in integrated circuits have significant impact on circuit speed. An accurate monitoring of these parameters can help to improve interconnect performance during process development, provide information for circuit design, or give useful reference for circuit failure analysis. Existing extraction methods either are destructive (such as SEM measurement) or can determine only partial parasitic parameters (such as large capacitor measurement). In this paper, we present a new method for extracting interconnect parasitic parameters, which can simultaneously determine the interlayer and intralayer capacitances, line resistance, and effective line width. The method is based on two test patterns of the same structure with different dimensions. The structure consumes less wafer area than existing methods. The method shows good agreement with SEM measurement of dielectric thickness in both nonglobal planarized and chemical-mechanical polished processes, and gives accurate prediction of the process spread of a ring oscillator speed over a wafer     

CTS-26型超声探伤仪典型故障的分析与排除

在简要介绍CTS-26型超声探伤仪工作原理及组成的基础上。对其几种典型故障作了具体的分析和处理。     

气囊内模制作桥面板在华丰湾防洪工程中的应用

采用气囊作内模进行浇筑桥面板混凝土 ,加快了预制桥面板施工进度 ,确保工程施工质量 ,并降低了工程施工成本