POSITIVE SOLUTIONS OF TWO-POINT BOUNDARY VALUE PROBLEMS OF DIFFERENTIO-INTEGRAL EQUATIONS

１ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｔｈｉｓｐａｐｅｒｗｅｃｏｎｓｉｄｅｒｔｈｅｅｘｉｓｔｅｎｃｅｏｆｐｏｓｉｔｉｖｅｓｏｌｕｔｉｏｎｓｏｆｔｈｅｆｏｌｏｗｉｎｇｓｅｃｏｎｄｏｒｄｅｒｎｏｎｌｉｎｅａｒｄｉｆｅｒｅｎｔｉｏ－ｉｎｔｅｇｒａｌｅｑｕａｔｉｏｎ...     

模糊数学及其应用简介

模糊数学及其应用简介黄兰德（汕头大学５１５０６３）模糊数学是解决模糊性问题的数学分支．所谓“模糊”是相对于“精确”而言的．过去人们研究的问题大都是“精确”的．比如一个电路，不是断开的就是接通的，非此即彼，决不模棱两可．反映这种现象的数学基础是经典集合...     

ICP-AES测定中药黄连中微量元素

以HNO3-H2O2体系湿法消解黄连,在确定的ICP-AES条件下测定其中的Ca、Cu、Fe、Mg、Mn、Zn元素含量.结果表明该方法相对标准偏差为2.4%-6.6%,回收率在92.5%-103.9%之间.湿法消解和ICP-AES测定黄连中6种微量元素,方法简便可靠.     

Compact extended cavity diode laser system for small optically pumped cesium beam frequency standards

A compact extended cavity diode laser (ECDL) system operating at 852 nm for small optically pumped cesium (Cs) beam frequency standards was reported. ECDL and a saturated absorption spectroscopy setup were all built in an aluminum box with dimension of 10×10×7 (cm). ECDL was based on a Littman-Metcaff configuration, whose free-running linewidth was less than 600 kHz. A digital automatic frequency lock unit (AFLU) was developed to lock the laser frequency to specify Cs absorption lines automatically and re-lock it in case of lock broken. With AFLU, the laser frequency was continuously locked for several weeks.     

拓宽思路进行课堂演示的一点尝试

介绍了利用激光器及改装的螺旋测微计在课堂上演示障碍边缘衍射，反映衍射、单缝衍射和散斑现象的方法及取得的教学效果。     

230-300MHz太阳射电声光频谱仪

为了观测太阳米波射电现象的动态频谱,研制了一台数字式米波太阳射电声光频谱仪。其设计指标适合于观测太阳宁静期间不太罕见的Ⅰ型射电爆发。频带范围230—300MHz,频谱分辨率250kHz,时间分辨率80ms。声光器件是采用钼酸铅偏转器,数据采集使用光电二极管阵加微计算机。软件具有爆发判断、仪器频响修正和自动绘图输出功能。馈源采用对数周期天线。该声光频谱仪与云南天文台的10m口径射电望远镜相连接,可清晰地观测到与太阳黑子群相关的Ⅰ型射电爆发的动态频谱图象。     

借助函数图像解不等式恒成立问题

“不等式恒成立,求参数的取值范围”是不等式中的一大题型,不等式有千姿百态,因此常令同学们不知如何着手解决,当不等式经过变形后,不等式两边的函数图像易画出时,可借助图像来求解.     

LiYF_4:Pr~(3+)能级晶场分裂链的计算

本文首次在稀土离子晶场光谱拟合中引进了唐敖庆等人的张量算符方法,从而获得了激光和上转换材料LiYF_4:Pr~(3+[2])对应于晶场群链(R_3T_dD_(2d)S_4)的能级分裂链,逐级晶场参量值和逐级近似波函数。这就为分析其有关空间电荷分布构形,讨论其光谱强度和其它光学、磁学、热力学性质等提供了逐级近似的依据。     

ON THE FINITE DISPLACEMENT PROBLEM OF A HOLLOW CYLINDER UNDER INTERNAL AND EXTERNAL PRESSURES

Using the method of successive approximations we find of this boundary-value problem the first-and second-order solutions. And then we obtain the formulae in the second approximation for the displacement, strain, and stress fields. Also, our results show that after deformation (ⅰ) a cross-section of the cylinder must be displaced into a plane section perpendicular to the central axis of the cylinder; and (ⅱ) neither the sum of the strain components E_(RR)~(2) and E_(φφ)~(2) nor the sum of the stress components ∑_(RR)~(2) and ∑_(φφ)~(2) maintains contant throughout the Cylinder. The latter effect, which is absent from classical elasticity, bears respensibility for the presence of the ∑_(ZZ)~(2). Moreover, there exhibits a linear relation between ∑_(ZZ)~(2) and (∑_(RR)~(2)+∑_(φφ)~(2)). with the proportionality coefficients depending only on the material of the cylinder.     

一类数列极限的级数解法

介绍一类数列极限存在性的级数解法.