金霉素产生菌F—303的选育及发酵特性

以金霉素产生菌H-502作为出发菌株,采用紫外线加氯化锂作为复合诱变剂,通过生物技术手段获得了F-303变株。投产结果表明,该复株具有孢子萌发率高,发酵周期短,发酵单位高和放罐体积大的特点,发酵指数超过国际先进水平。     

走近"京东方(BOE)"(下)

京东方十多年来飞速发展的基本经验被归纳为四个字:战略致胜.我国早在两千多年前就认识到战略决策的重要作用:运筹帷幄之中,决胜千里之外.正确的战略思想,成功的战略手段和有效的战略执行力就是京东方战略制胜的基本内涵.……     

果酸脂质体的制备

以高纯度大豆卵磷脂为包装材料，用反相蒸发法制备出果酸脂质体。用透射电子显微镜表征了其形态结构，并证实其直径为100－300nm，比较了果酸质量浓度对包封率的影响，脂质体溶液浓度和温度对泄漏率的影响，稳定剂用量对脂质体液的影响。结果表明，果酸质量浓度是0．3g／L时可以得到较好的包封率，丙二醇的适宜质量分数是5％－15％，一般浓度增加会使脂质体的泄漏率升高。     

Pushing Multiple Convertible Constrains into Frequent Itemsets Mining

Constraint pushing techniques have been developed for mining frequent patterns and association rules. How ever, multiple constraints cannot be handled with existing techniques in frequent pattern mining. In this paper, a new algorithm MCFMC （mining complete set of frequent itemsets with multiple constraints） is introduced. The algorithm takes advantage of the fact that a convertible constraint can be pushed into mining algorithm to reduce mining research spaces. By using a sample database, the algorithm develops techniques which select an optimal method based on a sample database to convert multiple constraints into multiple convert ible constraints, disjoined by conjunction and/or, and then partition these constraints into two parts. One part is pushed deep inside the mining process to reduce the research spaces for frequent itemsets, the other part that cannot be pushed in algorithm is used to filter the complete set of frequent itemsets and get the final result. Results from our detailed experi ment show the feasibility and effectiveness of the algorithm.     

信息化概念和意义探讨

从信息理论、信息技术的基本概念出发,探讨信息化的本质和信息化建设对社会的作用和意义.也提出信息化建设与系统高效率、知识经济和创新的相关关系.     

Eavesdropping on the Orderly-Encrypting Multiparty Quantum Secret Sharing Protocols

0 IntroductionSuppose the president of a bank,Alice,wantsto give ac-cess to a vault to two vice-presidents ,Bob and Charlie,whomshe does not entirely trust .Instead of givingthe secretto any one of them,she may desire to distribute the informa-tioninsuch a waythat no vice-president alone has any knowl-edge of the secret ,but both of themcanjointly determine thesecret .Cryptography provides the answer to this question inthe formof secret sharing[1 ,2],where secret messages are dis-tributed amo…     

相控阵雷达的自适应旁瓣对消系统中的几个问题

本文讨论了相控阵雷达旁瓣对消系统中的几个问题,经过分析,都得到明确的结论,可用于工程设计。     

组合夹具CAD中子组装模块参数化设计的研究

本文提出了组合夹具CAD子组装模块的概念,进行了参数化设计的探讨。文中重点叙述了参数化设计的方法及其优越性,并对设计中的具体问题,如夹具元件的确定,参数的输入、模块的生成等,做了深入的介绍。     

Chemical investigation of hassium (element 108)

The periodic table provides a classification of the chemical properties of the elements. But for the heaviest elements, the transactinides, this role of the periodic table reaches its limits because increasingly strong relativistic effects on the valence electron shells can induce deviations from known trends in chemical properties. In the case of the first two transactinides, elements 104 and 105, relativistic effects do indeed influence their chemical properties, whereas elements 106 and 107 both behave as expected from their position within the periodic table. Here we report the chemical separation and characterization of only seven detected atoms of element 108 (hassium, Hs), which were generated as isotopes (269)Hs (refs 8, 9) and (270)Hs (ref. 10) in the fusion reaction between (26)Mg and (248)Cm. The hassium atoms are immediately oxidized to a highly volatile oxide, presumably HsO(4), for which we determine an enthalpy of adsorption on our detector surface that is comparable to the adsorption enthalpy determined under identical conditions for the osmium oxide OsO(4). These results provide evidence that the chemical properties of hassium and its lighter homologue osmium are similar, thus confirming that hassium exhibits properties as expected from its position in group 8 of the periodic table.