ANALYSIS OF AN SI EPIDEMIC MODEL WITH NONLINEAR TRANSMISSION AND STAGE STRUCTURE

A disease transmission model of SI type with stage structure is formulated. The stability of disease free equilibrium, the existence and uniqueness of an endemic equilibrium, the existence of a global attractor are investigated.     

Weighted integral inequalities for conjugate A-harmonic tensors

We first prove a local weighted integral inequality for conjugate A-harmonic tensors. Then, as an application of our local result, we prove a global weighted integral inequality for conjugate A-harmonic tensors in L^s(μ)-averaging domains, which can be considered as a generalization of the classical result. Finally, we give applications of the above results to quasiregular mappings.     

用低次叠样条函数逼近导函数

本文讨论了用低次样条函数的叠样条来逼近导函数的问题.给出了叠样条的构造、误差分析及余项的逐项渐进展开式.     

光子扫描隧道显微镜的光电成像系统研究

本文论述了光子扫描隧道显微镜（ＰＳＴＭ）的显微成像机理、成像规律，针对具体的物理模型进行数值模拟计算，并得到了与实际探测相一致的场分布规律。采用自行研制的光子扫描隧道显微镜（ＰＳＴＭ）的显微实验系统对多种样品进行了表面显微成像研究，获得了关于样品表面三维立体图像信息，通过多种图像处理手段对原始图像进行后期处理，得到了更具视觉效果、更为逼真的样品表面图像。     

ICP－AES法分析水质的探讨

本文用ＩＣＰ－ＡＥＳ（电感耦合等离子体－原子发射光谱法）测定水中Ａｌ、Ｂ、Ｂａ、Ｂｅ、Ｃａ、Ｃｄ、Ｃｏ、Ｃｒ、Ｃｕ、Ｆｅ、Ｍｇ、Ｍｏ、Ｍｎ、Ｎｉ、Ｐｂ、Ｓｒ、Ｖ、Ｚｎ等１８种微量元素。方法简便、快速，只将样品简单酸化，即可测定。方法检出限为０．０００５－０．５μｇ／ｍＬ。相对标准偏差＜１８％     

Urn模型的B网及其应用

Urn模型的离散概率分布被用于构造逼近格式,具有Bernstein多项式的许多特性。本文用B网技术对Urn模型概率分布给出新的解释,指出了Urn模型B网的诸多性质,导出分布函数曲线的导数公式,构造了Urn分布的对偶基及与此相关的拟插值算子。     

沉浮,俯仰及控制面振动引起的跨音速非定常气动载荷计算

本文将文献[9]提出改进的通量分裂方法,应用于随时间变化的贴体网格中,建立了可用于求解非定常Euler方程的通量分裂方法.该方法是以连续的特征值分离为基础,它具有方法简单,便于推广使用的特点.同时克服了Steger-Warming通量分裂方法存在的问题.对通量分裂后的Euler方程.利用MUSCL型迎风差分建立了具有二阶精度的有限体积方程.文中以NACA64A—10翼型为例,对其在跨音速流场中进行沉浮、俯仰及带有振动控制面引起的非定常气动载荷进行了计算.部分计算结果与相应的实验结果进行了比较,吻合良好     

First-principles study on the metallic antiferromagnet Co[PhPO3]·H2O

The electronic structure and the magnetic properties of transition metal phosphonate Co(PhPO₃)·H₂O have been studied by first-principles within the density-functional theory (DFT) and the full potential linearized augmented plane wave (FP-LAPW) method. The total energy, the total magnetic moment, the atomic spin magnetic moments and the density of states(DOS) of Co(PhPO₃)·H₂O were all calculated. The calculations reveal that the title compound is a metallic antiferromagnet and has a metallic ferromagnetic metastable state, which are in good agreement with the experiment. The spin magnetic moment of Co(PhPO₃)·H₂O is about 4.93 _μB${\mu }_{\mathrm{B}}$ per molecule, and it is mainly assembled at the cobalt atom, at the same time, with a little contribution from the P, O1, O2, O3.     

Entropy of Einstein—Maxwell-Dilaton—Axion Black Holes

The entropy of Einstein—Maxwell-dilaton—axion black holes is calculated by using the improved brick-wall model. Taking into account of the statistical physics, we propose not to consider the superradiant modes. The result shows that the nonsuperradiant modes do contribute exactly the area-law entropy for extreme black hole. Moreover, our cut-off which does not require an angular cut-off is independent of angle . As for the extreme black hole, we found that its entropy is zero.     

幂硬化介质中平面应力动态裂纹的尖端弹塑性场

本文采用塑性动力学方程,对幂硬化介质中平面应力动态裂纹尖端场进行了渐近分析,其结果表明:在裂纹尖端附近,应力具有的奇异性,应变具有的奇异性,其中A是一个与塑性区尺寸有关的常数因子,r是离开裂纹尖端的距离,n为硬化指数,文中给出了尖端场的控制参量D,它依赖于马赫数;并且给出了各物理量的角函数。