全光纤激光器自启动锁模特性的理论研究

分析了带非线性放大光纤环的全光纤激光器的自启动锁模特性，得到了计算该激光器中光脉冲的有效能量增益的理论模型．结果表明，激光器的自启动锁模同掺Ｅｒ３＋光纤的增益及纤芯的有效截面积有关，并计算了自启动锁模的阈值峰值功率大小．应用本文的理论模型能成功地解释观察到的实验现象．     

On the range of reversible random walks onZ 2 in a random environment

In this paper, a weak law of large numbers is obtained for the range of two dimensional reversible random walk in a random environment.Partly supported by NSF of China.     

Correlations between the quantum-chemical parameters of amino acids and regioselectivity of isotope exchange with the spillover hydrogen

The effective charges and the proton affinity of carbon atoms of α-amino acids were calculated by quantum-chemical methods. The relative reactivity of the C−H bonds of amino acids under conditions of high-temperature solid-state catalytic isotope exchange (HSCIE) was studied. Correlations between the electron structure of amino acids and the regioselectivity of the solid-state isotope exchange were established. The reactivity of the carbon atoms with high proton affinity increases under HSCIE conditions. An assumption was made that the interaction of a solid organic compound with the spillover hydrogen can be described as the electrophilic substitution at the saturated and aromatic carbon atoms. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1611–1617, September, 1997.     

最小方差组合证券集的性质

从分析最小方差组合证券集入手 ,研究了均值方差有效组合证券边界的性质 ,给出最小方差组合证券集是一个仿射集 ,并且对有效组合证券结构的统计特性进行了分析 ,对证券投资有一定的指导意义     

Superheavy nuclei in deformed mean--field calculations

The ground–state properties of superheavy nuclei are investigated within various parametrisations of relativistic and nonrelativistic nuclear mean–field models. The heaviest known even–even nuclei starting with Z = 98 are used as a benchmark to estimate the predictive power of the models and forces. From that starting point, deformed doubly magic nuclei are searched in the region 100 ≤ Z ≤ 130 and 142 ≤ N ≤ 190. Received: 6 April 1998 / Revised version: 16 June 1998     

光致气溶胶粒子加热的等效吸收系数

当激光加热气溶胶粒子,所有气溶胶粒子都将吸热,部份吸收的热量将储存在内部构成一个热阱;部分加热周围空气,改变周围空气的温度分布。本文将现有连续激光加热单个气溶胶粒子热晕的理论引入群体气溶胶粒子,建立了群体气溶胶粒子加热空气的等效吸收系数公式,计算了不同类型的粒子的等效吸收系数以及延迟时间。     

Low energyK + scattering onN =Z nuclei

The data for the total cross-section ofK ⁺ scattering on various nuclei have been analysed in the Glauber multiple scattering theory. Energy-dependentK ⁺ -nucleus optical potential is generated using the forwardK ⁺ -nucleon scattering amplitude and the nuclear density distribution. Along with this, the calculated totalK ⁺ -nucleus cross-sections using the effectiveK ⁺ -nucleon crosssection inside the nucleus are also presented.     

Current algebra results for theB - D systems

Using the equal time commutation relations for the components of the vector and axialvector currents and keeping single particle states we obtain relations for the weak form factors for theB - D systems. In the heavy quark effective theory (HQET) limit these relations determine the Isgur-Wise function.     

关于丢番图方程的一个注记

本文得到了Ｓｈｏｒｅｙ和Ｔｉｊｄｅｍａｎ关于不定方程的一个猜想的一个结果，并且基本上解决了Ｅｄｇａｒ的关于上述不定方程的一个猜想．     

Symmetry Restoring Phase Transitions at High Density in a 4D Nambu-Jona-Lasinio Model with a Single Order Parameter

High density phase transitions in a 4-dimensional Nambu-Jona-Lasinio model containing a single symmetry breaking order parameter coming from the fermion-antifermion condensates are researched and expounded by means of both the gap equation and the effective potential approach. The phase transitions are proven to be second-order at a high temperature T; however at T = 0 they are first- or second-order, depending on whether A/m(0), the ratio of the momentum cutoff A in the fermion-loop integrals to the dynamicalfermion mass m(0) at zero temperature, is less than 3.387 or not. The former condition cannot be satisfied in some models. The discussions further show complete effectiveness of the critical analysis based on the gap equation for second order phase transitions including determination of the condition of their occurrence.