共查询到20条相似文献,搜索用时 15 毫秒
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前两篇论文是基於Арцимович-Recknagel公式,讨论了轴对称发射式系统中光电子初速度分布对於电子像品质的影响。本文在同样的基础上,但假定电子的初速度是按麦克斯韦分布,讨论了对应於点源和简单几何图形的面源所形成的电子像的强度分布,以及它们的分辨距离。不仅热电子发射可以用麦克斯韦分布描写,而且二次发射及光电发射也可以近似地用麦克斯韦分布描写。因此,本文的结果也可以用於光电发射及二次发射的浸没电子光学系统。具体计算的结果表明分辨距离的理论极限比Recknagel所获得而为大家所公认的结果(δ=4(kT)/(eE),不考虑强度分布的影响)要小一个数量级,其数值舆面源的几何形状有关,也舆像平面的位置有关。本文所得的公式舆结果可以应用於均匀平行的电磁场系统;并且对Wendt的论文提出一些意见。最后,对加速电源设计的要求略加讨论。 相似文献
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约瑟夫·约翰·汤姆孙爵士(SirJosephJohn Thomson,1856-1940)[1],1906年因发现电子而荣获诺贝尔奖金物理学奖.1911年他解释了正射线(positiverays),成为F.W.Aston(1877-1945)关于质谱研究工作的先导,并促进了同位素的发现.他一生发表过许多著作,并曾任英国皇家学会会长,是科学史上一位卓越的科学家.1893年,J.J.汤姆孙发表了?... 相似文献
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介绍了J.J.汤姆孙的科学生涯,探讨了汤姆孙对物理学的贡献,其中包括提出电磁质量、发现电子、进行原子结构的现代理论和极燧射线的研究等.最后,论述了汤姆孙在组织科学研究和培养科学人才方面取得的成就. 相似文献
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<正>众所周知,创建于1871年而竣工于1874年的卡文迪什实验室(Cavendish laboratory),是20世纪世界著名的物理学研究中心。经过100多年的发展,随着它规模的不断扩大,仪器设备的 相似文献
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《光谱学与光谱分析》2009,29(4)
著名光谱化学专家P.w.J.M鲍曼斯于2008年10月26 日逝世,享年76岁. 鲍曼斯1932年生予荷兰,于阿姆斯特丹大学化学物理系毕业.1961年获博士学位.1961~1968年间在阿姆斯特丹大学任教,从事原子光谱分析,发射光谱光源激发机理的研究.1966年出版专集:"Theory of Spectrochemical Excitation"1968年他进入Eindhoven的Philips研究实验室,曾任该实验室主任研究员 相似文献
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简要地论述了阴极射线的研究和电子的发现过程,以及J.J.汤姆孙和勒纳德在这些研究中的贡献。 相似文献
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《Surface science》1995,329(3):L624-L628
In a recent letter [A.B. McLean, C.E.J. Mitchell and I.G. Hill, Surf. Sci. 314 (1994) L925] it was suggested that life-time broadening alone could explain why surface state photoemission line-widths have been observed to increase as the initial states approach the Fermi level. I wish to point out that the used model is unphysical, that the agreement with experimental data is quite fortuitous, and that the experimental observations are satisfactorily understood in terms of established models. 相似文献
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《Surface science》1993,289(3):L638-L640
We calculate the dissociation energy of Ni clusters containing up to 13 atoms adsorbed on Ni(111), in order to elucidate its dependence on the cluster size. As opposed to what is claimed by Liu and Adams [Surf. Sci. 268 (1992) 73] the dissociation energy of Ni/Ni(111) does not display a marked peak for N =5, its value for this cluster size being indeed very close to what is found for N = 4 and N = 6. 相似文献
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《Solid State Communications》1986,60(3):299-300
Under the above title Galeener and Wright (GW) have criticized [1] a lengthy review article by me [2]. Their six-page discussion includes some cogent observations but also a number of misinterpretations of my model which I wish to correct here. I also wish to draw the reader's attention to recent refinements of my model not discussed by GW. 相似文献
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B. H. Lavenda 《Foundations of Physics Letters》2000,13(5):487-492
Fundamental errors in the Uffink and van Lith paper [Found. Phys.
29, 655-92 (1999)] are highlighted. Contrary to their claim, thermodynamic uncertainty relations are derived from the second law. To first order in the energy difference, the increase in entropy when two systems at slightly different temperatures are placed in thermal contact is equal to the product of the second subsystems multiplied by the change in energy of the first subsystem. This expression for the increase in entropy has the same range of validity as the thermodynamic uncertainty relations and the Fisher information, i.e., they are second order quantities. The dispersion in the inverse temperature of either subsystem cannot be less than the inverse of the Fisher information, or the inverse of the dispersion in energy of the composite system at the lowest possible equilibrium temperature, where the equality applies strictly to reversible processes and the inequality to irreversible ones. 相似文献
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