On the verge of <Emphasis Type="Italic">Umdeutung</Emphasis> in Minnesota: Van Vleck and the correspondence principle. Part one

In October 1924, The Physical Review, a relatively minor journal at the time, published a remarkable two-part paper by John H. Van Vleck, working in virtual isolation at the University of Minnesota. Using Bohr’s correspondence principle and Einstein’s quantum theory of radiation along with advanced techniques from classical mechanics, Van Vleck showed that quantum formulae for emission, absorption, and dispersion of radiation merge with their classical counterparts in the limit of high quantum numbers. For modern readers Van Vleck’s paper is much easier to follow than the famous paper by Kramers and Heisenberg on dispersion theory, which covers similar terrain and is widely credited to have led directly to Heisenberg’s Umdeutung paper. This makes Van Vleck’s paper extremely valuable for the reconstruction of the genesis of matrix mechanics. It also makes it tempting to ask why Van Vleck did not take the next step and develop matrix mechanics himself. This paper was written as part of a joint project in the history of quantum physics of the Max Planck Institut für Wissenschaftsgeschichte and the Fritz-Haber-Institut in Berlin.     

高速磁浮曲线地段简支轨道梁墩体系动力响应仿真

应用桥梁动力学、车辆动力学和电磁相互作用原理建立了高速常导磁浮交通车-梁-墩体系动力分析模型,利用数值积分求解了大规模非线性耦合动力方程.在此基础上结合具体线路条件进行了车线耦合动力学检算,得到了曲线地段车辆及梁墩体系动力响应基本规律.该部分的研究为制订合理的高速磁浮线路设计标准提供了理论依据.     

The Response of Debris-Flow Events to Solar Proton Flares （Ⅰ）

By analyzing the observation data from Dongchuan Debris Flow Observation and Research Station and historical data from year 1965 to 1990 gotten from National Astronomical Ob-servatories/Yunnan Observatory,the responding of debris flow in Jiangjia Ravine to Solar Proton Flare is studied. The following conclusion can be drawn. Solar Proton Flare,as one of most im-portant astronomical factors,affects the activity of debris flow in Yunnan. Generally,from 1965 to1990,the more active Solar Pro-ton Flare is,the greater the probability of high frequency and large runoff of debris flow is. On the contrary,the less active Solar Pro-ton Flare is,the greater the probability of low frequency,small runoff,and low sediment transport of debris flow is.     

卢梭自然主义教育思想及其现实意义

本文在阐述卢梭自然主义教育思想的理论基础和主要内容的基础上，理论联系实际，结合现代社会的教育问题，揭示了卢梭自然主义教育思想的现实意义。     

首达渗流中关于时间常数μ的上界估计

对2维首达渗流的时间常数μ给出了一个上界估计．     

Spectroscopic study on the photophysical properties of chlorine substituted tetraphenylporphyrin-histidine and its zinc(Ⅱ)complexes

As the structural analogues of (bacterio)chlorophylls in photosynthetic organisms, porphyrins play an important role in building up artificial photosynthetic systems[13]. In natural photosynthetic pigment-protein complexes,certain amino acid residuals modulate the reactions ofcharge transfer and energy transfer via coordination andother types of interactions with chlorophyll molecules.For instance, in higher-plant photosynthetic reaction cen-ter PSⅡ, the oxidization-reduction system consistin…     

Bang bang control of unified chaotic system

The unified chaotic system contains the Lorenz system and the Chen system as two dual systems at the two extremes of its parameter spectrum. This paper presents the design of bang bang controller for unified system and multitude of numerical experiments under various control parameters. Numerical experiments meet the theoretic proof perfectly and convincingly demonstrated the controller can be effectively used for unified systems with uncertainty of the equilibrium points. The method enriches the applications of chaotic control. Foundation item: Supported by the National Natural Science Foundation of China(50209012) Biography: Deng Xiao-ming (1980-), male, Master candidate, research direction: chaos control.     

西藏高山草原土放线菌研究初探

本文采用常规方法研究西藏6个分布于海拔4,240～4,850m 的高山草原土的放线菌数量,对从6个土样中分离纯化所得的454株放线菌中选出具有代表性的84株菌进行分离鉴定。结果表明:西藏同一土类不同土样中放线菌数量差异很大;84株代表性菌可分为9个属,链霉菌属(76.2%)占优势。     

计算复特征灵敏度的代数法

对于复特征灵敏度分析问题，文中给出了一种代数法求解公式。从理论分析的角度来说，所提出的方法既适全于单频，也适合于重频。为了说明算法的数值稳定性，文中给出了严格的数学证明。     

碱金属对焦炭反应性和反应后强度的影响

作者通过焦炭的浸碱试验，阐述了碱金属对焦炭反应性和反应后强度的影响，认为碱金属加速了焦炭的气化反应。显微组织研究表明，气化后的焦炭有明显的烧蚀现象。由此产生裂隙，形成许多脆弱薄壁的连通孔，导致焦炭强度下降，块度变小