忆N.F.Mott教授

读了《物理》杂志34卷第9期吴自勤和阎守胜两位同志写的关于N.F.Mott教授的纪念文章,很有感触,这使我回忆起Mott教授的一些往事.从这些往事中我深受教育,所以多年来未能忘怀。     

俄国物理学家N.G.巴索夫去逝

20 0 1年 7月 1日 ,著名俄国物理学家Ｎ .Ｇ .巴索夫逝世 ,终年 78岁 .巴索夫和美国物理学家汤斯、俄国物理学普罗霍罗夫一起由于发明微波激射器、激光器和从事量子电子学方面的基础研究 ,获得过196 4年诺贝尔物理奖 .巴索夫 192 2年 12月 14日生于莫斯科南面 4 80公里的沃罗涅茨附近的乌斯曼 .194 1年在沃罗涅茨中学毕业 .卫国战争期间他在军队中服役 ,194 3年在基辅军医学校毕业 ,在军队中工作到 194 5年卫国战争胜利 .194 6年到 195 0年 ,在莫斯科机械学院学习 .从 194 8年起 ,巴索夫开始在前苏联科学院列别捷夫物理研究所的振荡实验室工…     

Academician A.N. Sissakian 14.10.1944–01.05.2010

Chronicle

Academician A.N. Sissakian 14.10.1944–01.05.2010     

N.M.R. spectra of the XnAA′ Xn′ type

The method described previously for the calculation of the X spectrum for spin systems of of the X_nAA′X_n′ type is extended by means of magnetic equivalence factoring to cases in which the long-range coupling constant J_x is non-zero. This coupling is treated as a first-order perturbation to the energy levels obtained when J_x =0, and it is found that J_x may be measured directly from the separations between easily identified lines in the spectrum. A detailed account of the X ₃ AA′X ₃′ system is given, and the N.M.R. spectrum of fluoro-N,N′-dimethyl-1,3,2,4-diazadiphosphetidine is analysed. The spectral parameters obtained are discussed. A computer programme which calculates the spectra of systems involving magnetic equivalence is used to examine the validity of the approximations in the method.     

Mössbauer and N.M.R. studies of ErFe2Hx

Hydrides of Intermetallic compounds have been the object of many studies because of their potential applications/1/. Recent papers were devoted to the problem of interstitial site occupation in connection with H-H exclusion rule (d_H–H > 2.1 A). The present work deals with ErFe₂H_X, which has been investigated both by⁵⁷Fe Mössbauer Effect and by¹⁶⁷Er N.M.R. Previous studies were limited to X 2, 3.5, 4.1. Here five values of x (1.45, 1.6, 1.84, 2.6, 3.3) are considered, in order to obtain information on hydrogen location, filling and diffusion as a function of x, and also on hydrogen contribution to the electric field gradient (E.F.G.) and crystalline field at the Rare Earth.     

N.A.0.75平场复消色差显微物镜光学设计

为解决普通生物显微物镜视场小、场曲和色差严重的问题,本文利用光学软件Code V设计了一款20×平场复消色差显微物镜,通过合理的结构优化、光焦度分配及材料选择,使该物镜具有大视场、高数值孔径、平场复消色差的特点。设计分析结果表明,该物镜平场数为0.11 μm,最大焦移量为0.5 μm,满足显微物镜国际标准的规定;光学传递函数(MTF)曲线与理论衍射极限接近,达到指标要求,该物镜在可见光范围内实现了平场复消色差设计。公差分析结果表明RMS波前差劣化至0.24λ,能够满足加工和实际应用要求。     

Conformational Studies of α-Substituted Carbonyl Compounds by I. R. Spectroscopy. II. α-Heterosubstituted N,N-Diethylacetamides

Abstract

The α-heterosubstituted N, N?diethylacetamides(1–8) cis/gauche conformations population ratio have been estimated through the analysis of the carbonyl group stretching vibration in the carbon tetrachloride and in chloroform. The substituent steric properties determine the cis/gauche ratio which decreases as the substituent size increases. For most of the studied amides, the gauche rotamer carbonyl band exhibits larger shifts to lower frequencies than in the corresponding α-heterosubstituted propanones¹, but for the α-chloro-(4) and for the α-bromo-N,N?diethylacetamide(5) a reverse trend is observed. This behavior can be related to changes in the πC=O C—X Dihedral angle, an hyperconjugative effect being sugges ted to explain the frequency shifts of the gauche rotamers.     

Beugung elektromagnetischer Wellen in Braunbekscher Näherung. II

The extension, given in a previous paper, ofBraunbek's approximation method to the diffraction of electromagnetic waves, is applied to the near field of the circular aperture and the circular disk. The field distributions along the central axis and in the plane of the screen are calculated and compared with the results of both the rigorous solution andKirchhoff's approximation. The relation ofBraunbek's method to other approximation methods for the optical region is discussed.     

The 1/N F expansion of the γ and β functions in Q.E.D.

The Callan-Symanzik- and-functions are calculated analytically for Q.E.D. in the limit of a large number of leptons (N _F) up to terms of order 1/N _F inclusive. We give closed analytic expressions for the coefficients of these terms in their series expansion in powers ofK N _F/. We have been able to sum these series and to obtain some striking results.     

Beugung elektromagnetischer Wellen in Braunbekscher Näherung. I

An approximation method proposed by Braunbek for the diffraction of scalar waves by plane obstacles, or apertures in a plane screen, is extended to the diffraction of electromagnetic waves. As an example, the diffraction of a linearly polarized plane electromagnetic wave normally incident on a circular aperture in a perfectly conducting plane screen and on a perfectly conducting plane circular disk is considered in detail. The results are compared with those obtained from the exact solution ofMeixner andAndrejewski and with the results ofKirchhoff's approximations. It is shown that, in contrast to theKirchhoff approximations,Braunbek's method leads in all cases to the correct ‘optical’ limits and represents a good approximation even for wavelengths comparable with the size of the obstacle. After a general formulation ofBraunbek's method in the electromagnetic diffraction problem, we calculate in the present paper the far field of the circular aperture and the transmission coefficient by means of the cross section theorem. The near field of the circular aperture and the circular disk will be considered in a subsequent paper.     

Complex relativity and real solutions. III. Real type-N solutions from complexN ⊗N ones

Einstein's vacuum field equations are integrated in complex relativity in a major subcase of the class whose Weyl tensor is of the type NN, i.e., when the left and right Weyl spinors and are each of typeN. The subcase is the complex equivalent of the real nontwisting case. Five separate families of solutions are found. Three of these are complexified versions of the two families of plane-fronted waves and the Robinson-Trautman real type-N metrics and two are complex solutions which do not have any real slices of Lorentz signature. Before the equations are integrated, the relevant general theory and equations are developed in a tetrad frame which is well suited to the discussion of these and a wider class of complex solutions and is called aleft quarter flat frame. The relationship between this frame and the coordinates used and some other frames and coordinates, including the complexified version of the frame often used for real type-N metrics, is discussed.     

关于T.Shiraiwa与N.Fujino的荧光X射线强度公式的研究

本文揭示了T.Shiraiwa及N.Fujino推导荧光X射线强度公式的思路,解决了dx_1/sinψ、dx_2/sinψ及(2πr_1dr_1)/(4πR_1~2)等项的物理意义含糊不清的疑团,指出了他们的两个错误及出错的原因,并作了恰当的相同校正。     

Field-induced spin-orientational phase transitions in Néel ferrimagnets. I

The breakdown of the aligned states of Néel ferrimagnets in an applied magnetic field is considered. The behaviour of isotropic two-and three-sublattice ferrimagnets is treated in the framework of the mean-field approximation. A phenomenological method also limited by the mean-field approximation is used to analyse the behaviour of the anisotropic ferrimagnet. Particular emphasis is placed on the vicinity of the compensation temperature. Approximate analytical expressions which are valid near the compensation temperature are given for the phase-boundary positions, typical magnetic fields, and temperature ranges of the phase diagrams.     

Comment on “Foam imbibition in microgravity. An experimental study” by H. Caps,H. Decauwer,M.-L. Chevalier,G. Soyez,M. Ausloos and N. Vandewalle

In a recent paper, [1] described parabolic flight experiments showing the movement of liquid into the foam during the microgravity phase. In this comment, we present a detailed theory of this process, supported by numerical calculations, confirming their conclusion that the wetting front moves with the square root of time. We further show that this diffusion process is similar for different surfactant systems, which allows us to provide bounds on the value of the diffusion coefficient.Received: 28 April 2004, Published online: 3 August 2004PACS: 82.70.Rr Aerosols and foams - 83.80.Iz Emulsions and foams     

Development of A. N. Terenin’s Ideas at Tomsk State University: Stages and Personalia

Russian Physics Journal - The stages of development of molecular photonics at Tomsk State University are presented. It was A. N. Terenin’s student, N. A. Prilezhaeva, who pioneered the...     

Singular Dimensions of the¶N= 2 Superconformal Algebras. I

Verma modules of superconfomal algebras can have singular vector spaces with dimensions greater than 1. Following a method developed for the Virasoro algebra by Kent, we introduce the concept of adapted orderings on superconformal algebras. We prove several general results on the ordering kernels associated to the adapted orderings and show that the size of an ordering kernel implies an upper limit for the dimension of a singular vector space. We apply this method to the topological N= 2 algebra and obtain the maximal dimensions of the singular vector spaces in the topological Verma modules: 0, 1, 2 or 3 depending on the type of Verma module and the type of singular vector. As a consequence we prove the conjecture of Gato-Rivera and Rosado on the possible existing types of topological singular vectors (4 in chiral Verma modules and 29 in complete Verma modules). Interestingly, we have found two-dimensional spaces of singular vectors at level 1. Finally, by using the topological twists and the spectral flows, we also obtain the maximal dimensions of the singular vector spaces for the Neveu–Schwarz N= 2 algebra (0, 1 or 2) and for the Ramond N= 2 algebra (0, 1, 2 or 3). Received: 19 August 1998 / Accepted: 15 March 1999