黄昆的创新思想与科学贡献

黄昆是我国著名物理学家,也是国际著名物理学家.他的学术生涯不同凡响,值得学界研究,值得物理界年轻学人借鉴;他的科学创新方法以及严谨的科学态度值得深入系统研究、学习;他的科学贡献,尤其对于新中国物理界的突出奉献,应写入中国物理学史册.     

真人真知 典范永存

吴大猷先生（1907—2000）是中国老一辈物理学家和教育家,他因在分子物理、核物理等领域做出的重要贡献而享誉国际物理学界。他毕生献身于科研和教学．为祖国培养出一批很杰出的科学技术人才,对20世纪中国近代物理学的发展具有深刻的、划时代的影响。特别是．20世纪50年代以来他对我国台湾地区的科学与教育事业做出了巨大的贡献。2008年6月7日,为缅怀吴大猷先生高尚的风范和杰出的贡献,中国物理学会、中科院数理学部、中国高等科技中心、北京大学和南开大学联合在京主办“吴大猷先生诞辰100周年纪念会”,周光召、朱光亚、陈佳洱、杨振宁、李政道等物理学家将参加纪念会并发言。本刊被授权独家刊登部分发言,以飨读者。让我们永远怀念吴大猷先生。     

吴大猷先生与狄拉克的交往

 和一位一代泰斗的物理学家相处三个月的经验,是很难得的.--吴大猷吴大猷先生诞生于1907年9月29日,今年是他86岁寿庆.狄拉克出生于1902年8月8日,逝世于1984年10月20日,今年是他冥诞91周年.吴先生是中国的一代名师;他培养了李政道和杨振宁两颗灿烂的明珠,狄拉克是著名数学物理学家、量子力学的创始人之一.在吴先生和狄拉克之间有过一段亲密的交往,这在今后若干年内的中国物理学界和中国科学史界中必将引起人们长久的津津乐道.     

《对玻恩及其学派的系列研究》连载⑧——玻恩对弟子杨立铭研究工作的高度评价

杨立铭是玻恩培养的第三个中国物理博士,也是他培养的最后一位中国学生.1950年至1951年,玻恩在写给一些重要物理学家(如玻尔、海森伯、费米、魏格纳、约当等人)以及写给一些重要期刊的信函中,高度评价杨立铭当时的研究成果.阅读这些信函,可以感觉到玻恩培养学生的强烈责任心以及那份对中国弟子的欣赏与喜爱.这些以前不为世人所知晓的信函,是中国物理学与世界接轨的宝贵、动人的文献,需要中国物理学史研究者进一步深入研究,需要更多中国物理界人士了解并关注.     

纪念卓益忠先生

<正>卓益忠先生,福建罗源县人,理论物理学家,我心中敬爱的良师益友。他物理思想活跃,在核物理、统计物理和生物物理的理论发展方面都作出了重要贡献,是中国核事业和国防科学技术事业的基础核数据研究的开拓者之一,我国镇国重器后时期核物理基础科学研究的开拓者之一。卓益忠先生1932年1月24日出生,2017年1月29日辞世,享年86岁。他1951年就读于吉林大学物理系,1955年毕业分配到中国科学院     

为了忘却的怀念——回忆晚年的叶企孙

叶企孙 (1898— 1977)是中国物理学界卓越的先辈学者之一 ,曾先后任清华大学和北京大学物理学教授 .除了在测定普朗克常数和高压磁学方面贡献优异之外 ,他的最大成就还是培养了中国几代物理学家 .出入其门的优秀物理人才之多不下于国际上任何一个“物理中心”或“学派” .本文是作者经历的叶企孙晚年情景之点滴 .叶企孙是 195 4年成立的全国自然科学史委员会副主任委员 .在他的积极倡导与建议下 ,于 195 7年成立了中国自然科学史研究室 .该研究室成立时隶属中国科学院哲学社会科学部 .1978年哲学社会科学部改组成中国社会科学院 ,中国自然科…     

著名物理学家吴大猷教授逝世

 吴大猷先生,１９０７年９月２９日生于广东,于２０００年３月４日在台北逝世,享年９３岁．海内外的华人物理学工作者无不为失去了一位对物理学研究做出了重要贡献的中国现代物理学的先驱而感到十分悲痛．吴大猷教授学识渊博,学术造诣精深,是国际上著名的物理学家．他１９２９年毕业于南开大学,１９３１年赴美国密歇根大学在塞缪尔·高德斯密特（ＳａｍｕｅｌＡ．Ｇｏｕｄｓｍｉｔ）教授的指导下,从事研究工作,１９３３年取得物理学博士学位．他有关重元素的工作指出了自然界存在超铀元素．他１９３４年２７岁从密歇根大学学成回国,到北京大学任教授,是中国历史上最早获得美国大学物理博士的三人之一．     

一代宗师,科学泰斗--黄昆院士

黄昆先生是世界著名的物理学家，他对固体物理学作出了许多开拓性的重大贡献，是我国固体物理学和半导体物理学的奠基人之一．他的理论产生着深远的影响，不仅对固体物理学的发展具有重要的理论意义，而且对信息产业具有重要的现实指导意义．新中国成立以来，他投身于国家教育事业，从事于普通物理、固体物理和半导体物理等的教学工作，培养了一批又一批国家科技栋梁之才．黄昆先生与《物理》有着深厚的缘分，他在《物理》上发表的文章受到读者的广泛关注，令《物理》增色；黄先生也曾多次表示《物理》是他晚年以来唯一坚持阅读的期刊，足见黄先生对《物理》的喜爱．2005年7月6日，黄昆先生不幸逝世，我刊特组织这组文章以表达我们对先生的深切悼念和深深的哀思．伟人已逝，但先生的精神与风范长存．     

纪念吴有训先生

吴有训先生是中国近代物理学的先驱者,是中国物理学会的创始人之一.他不仅是一位有成就的物理学家,而且是一位杰出的教育家和科学研究的组织者.他一生中培养了许多物理人才,至今还活跃在我国物理学领域中. 我不是吴老的学生,但吴老对我的关心和教诲决不亚于对他自己的学生.三十     

费因曼:巧解航天失事之谜的科学通才与教育家

本文通过对理查德·费因曼在现代物理学与物理教育领域内的卓越贡献,巧解“挑战者号”航天飞机失事之谜,以及他对科学美的鉴赏、评判和执着的追求等的论述,详实地揭示了他不愧为20世纪最杰出的物理学家、教育家和科学通才之一.     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

Femtosecond Transform-Limited Pulse Generation by Compensating for the Linear Chirp of SPM Spectra in Dispersion Shifted Fibers

A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.     

Sorting of bending magnets for the SSRF booster

The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.     

Measurement of nonlinear coefficient of optical fiber based on small chirped soliton transmission

We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG),and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed.     

Resonance scattering of canonical elastic shells in absorbing fluid medium

Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell.     

Single-beam self-referenced phase-sensitive surface plasmon resonance sensor with high detection resolution

A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.     

Influences of SiO2 protective layers and annealing on the laser-induced damage threshold of Ta2O5 films

Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.     

A stereo matching algorithm using multi-peak candidate matches and geometric constraints

Gray cross correlation matching technique is adopted to extract candidate matches with gray cross correla- tion coefficients less than some certain range of maximal correlation coefficient called multi-peak candidate matches. Multi-peak candidates are extracted corresponding to three closest feature points at first. The corresponding multi-peak candidate matches are used to construct the model polygon. Correspondence is determined based on the local geometric relations between the three feature points and the multi-peak candidates. The disparity test and the global consistency checkout are applied to eliminate the remaining ambiguous matches that are not removed by the local geometric relational test. Experimental results show that the proposed algorithm is feasible and accurate.