A knowledge-based system for sensor selection

This paper presents a Knowledge-based system (KBS) developed to allow users, who may not be knowledgeable about sensors, to select sensors suitable for their specific needs. The KBS runs on a micro-computer. The selection criteria are user specified and are based on the desired measurement parameters. The system output includes all of the operational and dimensional parameters of the recommended sensor, price, and vendor information.     

微重力落塔电磁悬吊、释放技术研究

论述了微重力落塔电磁悬吊、释放、提升机构的关键技术,电磁释放过程的特性分析以及微重力落塔实际试验的情况。分析说明:悬吊、释放性能的好坏决定了试验落舱的微重力水平,也是微重力落塔试验能否成功的关键技术。     

WC对铜基和镍基喷焊覆层材料耐气蚀性能的影响

在CuNiSiB,NiCrSiB自熔合金粉末中添加WC陶瓷颗粒，利用氧乙炔焰粉末喷焊工艺制备覆层材料，用超声波振动气蚀仪对覆层材料进行耐气蚀性能研究，用扫描电子显微镜对覆层材料表面气蚀破坏形貌进行观察，结果表明：复合覆层材料的耐气蚀能力比基体强；提高CuNiSiB覆层材料耐气蚀能力的途径是强化晶界，还探讨了覆层材料的气蚀破坏机理。     

标准椅全身计数器对不同年龄组均匀体模源全能峰效率的刻度

本文介绍了用标准液体源均匀充入聚氯乙烯制的体模,刻度标准椅全身计数器〔φ8″×4″(NaI)〕的方法和结果。分别就代表6个年龄组的体模,测定了标准椅全身计数器对5种能量(364,637,898,1460和1836keV)γ射线的全能峰效率;给出了全能峰效率与γ射线能量和被测对象体重的关系曲线。     

北京谱仪端盖簇射计数器工作气体的研究

为使北京谱仪端盖族射计数器更好地工作在自猝灭流光ＳＱＳ模式下，提高其能量分辨以及线性等指标，用Ａｒ，ＣＯ２，Ｌｓｏｂｕｔａｎｅ三元工作气体对探测器的工作性能进行了仔细研究，找出了一适合于主雇地数器的工作气体，此外，还研究了异丁的纯度对探测器性能的影响。     

太钢电弧炉上应用四星接法MOA的必要性

分析了太钢电弧炉变压器高压侧相间过电压的产生原因，比较了用于限制过电压的避雷器的两种接法．结论是用四垦接法ＭＯＡ限制过电压的效果较显著．     

Do We Stand on Common Ground? A Threat Appraisal Model for Terror Alerts Issued by the Department of Homeland Security

The fabric and faces of threat, and the expediency and efficiency in the communication of threat, are examined with a threat appraisal model. This model is empirically tested on an ongoing communication challenge, the issuance of terror alerts by the United States' Department of Homeland Security (DHS), focusing on how threat is appraised by both the conservative and liberal audiences. Findings showed a shared view by the DHS and conservative audiences on the levels and nature of threats; liberal audiences thought otherwise. Though there appeared to be a consensus between the conservative and liberal audiences on the efficacy of threat communication, more internal consistency within DHS is needed to optimise its effectiveness.     

FBOLES—outline of a frequency-based on-line expert system approach for fault diagnoses in nuclear power plants

The basic concept of a novel frequency-based on-line expert system (FBOLES) approach for on-line fault diagnoses in nuclear power plants has been presented previously. This paper reports further progress, and includes how to express the uncertainties of expert opinion in knowledge-bases and propagate then in inferences, and how to deal with imperfect knowledge-bases. It also describes the main elements of FBOLES and outlines how the system works under complex conditions including the dynamic behavior of signals during accidents, multiple failures, and on-line changes of plant operation mode. Its ability to diagnose root causes of accidents has been tested using the main steam and feedwater condensate systems of a full-scale, three-loop, 950 MW nuclear power plant simulated by the Tsinghua simulator. So far the results seem good.     

Purification and renaturation of recombinant human lymphotoxin (tumour necrosis factor beta) expressed in Escherichia coli as inclusion bodies

High level expression of recombinant human tumour necrosis factor β (rh TNF-β) in Escherichia coli results in the formation of two portions of protein, namely soluble active protein and insoluble protein which is inactive and aggregates in the form of inclusion bodies (IBs). In this study, a procedure for purification and renaturation of rh TNF-β from inclusion bodies has been designed and verified experimentally with a product purity of more than 90% and a recovery of about 30%. The procedure includes washing of IBs with specific wash buffer (Triton X-100/EDTA/lysozyme/PMSF), their solubilization with 8 mol dm^?3 alkaline urea, purification with ion-exchange columns, refolding with renaturation buffer and finally concentration and desalination with an ultrafiltration membrane. The characteristics of the renatured protein were identical with those of purified protein from the soluble fraction as demonstrated by (1) SDS-PAGE, (2) cytotoxic activity on mouse L929 cells, (3) N-terminal amino acid sequence, and (4) gel filtration chromatography.