ICP—AES法同时测定海洋沉积物中七个元素

本法采用高频小功率等离子体为原子发射光谱源,用HF-HClO~4-HNO_3溶解样品,对海洋沉积物中Fe、Mn、Al、Mg、Ca、Ti和Sr进行定量分析。不加内标,不去溶,单次摄谱,简单、快速,各元素21次测定变动系数为:1.63～5.53%。     

角动量守恒的一个演示实验

用一个漏斗和一些沙可以方便地演示角动量守恒定律。我们所用的是马口铁做成的漏斗,其上口直径约15cm。取几条粗铜线焊在漏斗的上口边缘上,使漏斗能够自由地沿其轴线悬挂起来。在悬挂点,用一个低摩     

2DNMR鉴定吗啉付产物的结构

本文用~H—NMR,反门控定量~(13)C—NMR,异核丁—分解2D、同核化学位移相关2D、异核化学位移相关2D等技术,鉴定了二种未见报道的吗啉付产物结构。     

Darboux Transformation and Variable Separation Approach： the Nizhnik-Novikov-Veselov Equation

Darboux transformation (DT) is developed to systematically find variable separation solutions for the Nizhnik-Novikov-Veselov equation. Starting from a seed solution with some arbitrary functions, the one-step DT yields the variable separable solutions, which can be obtained from the truncated Painleve analysis, and the two-step DT leads to some new variable separable solutions, which are the generalization of the known results obtained by using a guess ansatz to solve the generalized trilinear equation.     

推广的Boussinesq方程和KdV方程——Painlevé性质,Bcklund变换和Lax对

本文从Kadomtsev-Petviashvili方程的对称性约化出发,得到了具有任意函数作为变系数的推广的Boussinesq方程和推广的KdV方程.利用Weiss和Kruskal等建立的奇性分析方法,我们证明了这两个方程可积的充分条件:Painlevé性质。得到了这两个方程的Bcklund变换和奇性流形方程(推广的Schwartz-Boussinesq方程和Schwartz-KdV方程)。并由此将这两个方程线性化,即给出这两个方程的Lax对并包含有明显的与时间无关的任意谱参数。     

排序原理在微积分中的一些应用

利用排序原理证明了数列{(1 1/n)~n}收敛性,级数∑(n!e~n)/(n~n p)在p≤3/2时是发散的和几个不等式。     

多孔岩芯渗透率与孔隙度的MRI研究

运用自旋回波序列,得到一系列用盐水饱和的多孔岩芯的磁共振自旋密度象,可以直观、准确地观察岩芯的结构,并对象的信号强度与渗透率和孔隙度之间的相关关系进行了分析,发现它们之间存在良好的定性关系,得到了较好的结果.     

三倍折反式电视跟踪变焦距物镜的设计

<正> 一、引言根据高斯光学,物象垂轴放大率为:β=(y′/y)=-(f/x)=-(x′/f′)此式表明,某一确定距离上的固定大小目标,通过定焦系统所成象的大小是一定的。随着距离的改变,象的大小也相应地改变。如果要求象的大小不随距离x的变化而变化,则必须使焦距f作相应的变化,即应用变焦距系统。     

Low Resistivity C54 Phase TiSi2 Films Synthesized by a Novel Two—Step Method

Synthesis and growth properties of the TiSi2 film on a Si (001) substrate are investigated. A novel two-step method is used for deposition of the C54 phase TiSi2 film with low resistivity. The first step is the formation ofthe C49 phase TiSi2 at a relative low substrate temperature of 400℃, followed by rapid thermal annealing processat 850℃ in N2 for the formation of the C54 phase TiSi2 as the second step. Finally, selective wet, etching isemployed to remove the un-reaction Ti on the surface and the low resistivity C54 TiSi2 film can be obtained. Thefilms deposited under various parameters are evaluated by scanning electron microscopy, x-ray diffraction and the resistivity measurement. Compared with other sputtering technologies used commonly for TiSi2 synthesis,this two-step method has apparent advantages such as the mild synthesis temperature and the high purity of the final product with low resistivity, uniform large area and improving surface roughness. In addition, the film also shows that the low coefficient of resistivity-temperature appears in the temperature range from 20℃to 800℃.     

Symmetries and Strong Symmetries of the （3＋1）-Dimensional Burgers Equatio

The strong symmetries (recursion operators) and the inverse strong symmetries of a (3 1)-dimensional Burgers equation are given explicitly.Infinitely many symmetries of the considered model are obtained by acting the strong symmetries and the inverse strong symmetries on some seeds.An infinite-dimensional full Lie point symmetry algebra is also given.