A MODEL OF THE STRUCTURE OF MESONS WITH A COVARIANT OSCILLATOR POTENTIAL

In this paper the internal wave functions of mesons are obtained by solving the Bethe-Salpeter equation with a pseudoscalar covariant oscillator potential.The transi-tion probabilities of various weak and electromagnetic processes of mesons are calculat- ed by using these wave functions.The results are qualitatively in agreement with experiments.Quantitatively the results given are in good agreements with experi- ments for processes not involving π mesons,but are not so for processes involving π mesons,for which we give some speculative explanations.     

回热器功产生的临界温度梯度研究

热声机械作为一种能量转化装置，能够不通过运动部件将热量转变成压力波输出，实现这一功能的关键部件就是回热器，本文讨论了丝网型回热器能在纯行波状态下起振的临界温度梯度与结构参数及运行参数的关系。     

OPTIMAL MANAGEMENT OF INVASIVE SPECIES WITH DIFFERENT REPRODUCTION AND SURVIVAL STRATEGIES

Abstract In this paper, a numerical model is developed for analyzing the role of species life history and age structure for the optimal management of a commercial resident species that is exposed to an invasive species. It is shown that reproduction and mortality characteristics of both species ands age structure of the invader at the time of invasion are important for the costs of invasions when the invader and resident species compete for scarce resources. Commercially harvested species with low juvenile survival and high reproduction are found to be economically more robust against invasions. Species with these life‐history traits are also the most damaging as invaders. Properties of the harvesting cost function and the discount rate are shown to be of importance for the development of the invader population over time. Hence, it is possible to identify specific combinations of life‐history characteristics and economic conditions under which invasions cause particularly large economic damage.     

n-Hg0.80Mg0.20Te界面积累层中二维电子气的输运特性研究

通过变磁场霍耳测量研究了MBE生长的Hg_0.80Mg_0.20Te薄膜在15 —250K温度范围内的输运特性.采用迁移率谱(MS)和多载流子拟合过程(MCF)相结合的方法对 实验数据进行了分析,由该方法获得的结果和Shubnikov de Hass(SdH)振荡测量的结果都证 明材料中存在二维(2D)电子和三维(3D)电子.其中2D电子主要来自于Hg_1-xMgxTe-CdTe的界面积累层或Hg_1-x关键词： 变磁场霍耳测量 界面积累层 二维电子气 1-xMg_xTe')" href="#">Hg_1-xMg_xTe     

图类^-αKα∪βCP（b）中的整谱图

设图G是一个简单图,图G的补图记为^-G,如果G的谱都是整数,就称G是整谱图．鸡尾酒会图CP（n）=K2n-nK2（K2n是2n阶完全图）和完全图Kα都是整谱图．本文确定了图类^-αKα∪βCP（b）中的所有整谱图．     

Cation-induced assembly of Zn(Ⅱ),Cd(Ⅱ) and Hg(Ⅱ) coordination complexes and DFT calculations to evaluate weak interactions between the helical chains

Two new coordination polymers [ZnLI2]∞ (1) and [CdLI2]∞ (2) (L: 3,6-di-(1,2,4-triazole-1-yl)-N-hexylcarbazole) were synthesized and their crystal structures were determined by single-crystal X-ray diffraction techniques.Complexes are both constructed with the helical chains along the 21 screw axis.The coordination bond,C-H···I weak interactions and π-πinteractions play significant roles in constructing their 3D or 2D frameworks.Two different DFT calculations are performed for the weak interactions between t...