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支原体研究:历史回顾与热点分析 被引量:1
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作者 s.razin L.Hayflick +1 位作者 徐泽锋 蒋小刚 《中国家禽》 北大核心 2012年第6期37-43,共7页
支原体研究始于1898年。支原体不仅是目前已知能自由生活的最小微生物,在自然界中广泛存在,很多种类还是动植物和人类的重要病原体,加上体外培养的细胞常常被多种支原体污染,其体积很小,能通过细菌滤器,因此支原体曾在最初的好几年中都... 支原体研究始于1898年。支原体不仅是目前已知能自由生活的最小微生物,在自然界中广泛存在,很多种类还是动植物和人类的重要病原体,加上体外培养的细胞常常被多种支原体污染,其体积很小,能通过细菌滤器,因此支原体曾在最初的好几年中都被认为是一种病毒。随后,人们发现了L型细菌,这种细菌和支原体形态相似,它也具有奇特的"油煎蛋"样菌落,于是,支原体与这种部分或全部缺失细胞壁的L型细菌混淆。20世纪五六十年代,关于支原体的文献对将支原体定义为L型细菌存在分歧。直到60年代末期,用DNA杂交技术获得的第一份基因分析数据,排除了支原体与稳定L型细菌的任何关系。现在已经认为L型细菌是有细胞壁的。尽管如此,从长远发展的眼光来看,将支原体与L型细菌联系起来也不是完全错误的。尽管现在对支原体已不陌生,但对微生物学家来说,支原体的性质、与其它微生物的关系和分类学情况在很长一段时间里都是谜团。因此,支原体研究越来越备受关注。本专题从支原体细胞形态学、生态学、体外培养、代谢途径、基因组测序、构建合成、致病机制研究,以及支原体黏附、抗原变异、免疫系统的调节作用等进行了全面系统的阐述,供兽医工作者参考。 展开更多
关键词 支原体 自由生活 致病力 细胞壁
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Gasdynamic ECR Sources of Multicharged Ions
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作者 S.Golubev A.Boldaanov +5 位作者 I.Izotov s.razin A.Sidorov V.Skalyga A.Vodopyanov V.Zorin 《Chinese Physics C》 SCIE CAS CSCD 北大核心 2007年第S1期238-238,共1页
A new type of pulse sources of multicharged ions,namely,a quasi-gasdynamic ECR source is propose.Its main difference from the classical ECR ion sources is a different,quasi-gasdynamic regime of plasma confinement in a... A new type of pulse sources of multicharged ions,namely,a quasi-gasdynamic ECR source is propose.Its main difference from the classical ECR ion sources is a different,quasi-gasdynamic regime of plasma confinement in a magnetic trap.A zero-dimensional model was constructed that describes gas breakdown, formation of charge state distribution in a plasma,and plasma flux through the plugs of the trap.A wide spectrum of model experimental studies was covered.Plasma was produced and heated by a pulse(1ms) gyrotron at the frequency of 37.5GHz and power of 100kW in a cusp magnetic trap with magnetic field in plugs up to 2.5T.Such a trap has axisymmetric configuration and allows one to realize a quasi-gasdynamic regime of confinement with reliable stabilization of MHD perturbations.It was demonstrated that with such a confinement regime it is possible to generate multicharged ions and create intense(more than 1A/cm^2)ion fluxes through the trap plugs.Comparison of results of calculations and data of experiments shows that they are in a good agreement,which allows us to predict with a high degree of certainty creation of an ECR source of a new generation. The data obtained were used to design a pulse quasi-gasdynamic ECR ion source with pumping at the frequency of 100GHz,effective trap size lm,average ion charge in plasma comparable with that in the best classical MCI ECR sources but with an order of magnitude higher flux density and absolute magnitude of plasma flux through trap plugs.Creation of intense plasma fluxes allows one to extract high-current MCI beams of high brightness.Transverse homogeneity of a plasma flux makes it possible to use multi-aperture extraction system for formation on broad intense MCI beams. 展开更多
关键词 电荷态 离子源 脉冲式
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