中心为氨基、末端为硝基的苯乙炔树枝状分子的合成

将固定相合成与“收敛/发散”方法相结合,合成了第一、二代苯乙炔树枝状分子.通过Heck-Cassar-Sonogashira-Hagihara偶联反应,将其中心和末端分别修饰上供电子的氨基和拉电子的硝基,得到第一、二代中心为氨基、末端为硝基的苯乙炔树枝状分子NH₂-G1-(NO₂)₂和NH₂-G2-(NO₂)₄.用傅里叶变换红外光谱跟踪了整个固定相合成过程.苯乙炔树枝状分子的紫外-可见吸收光谱呈现出规律性变化.     

On the Extrapolation of Perturbation Series

We discuss certain special cases of algebraic approximants that are given as zeroes of so-called effective characteristic polynomials and their generalization to a multiseries setting. These approximants are useful for the convergence acceleration or summation of quantum mechanical perturbation series. Examples are given and some properties discussed.     

无机化学教学中“原子结构”内容怎样突破重点和难点*

基于对“原子结构”内容的科学界定,认为章节定名为“原子与原子结构”较为合理,讲授内容应包含原子的结构和性质、原子结构模型的建立和演变、核外电子的排布、原子核结构模型简介和原子结构与元素周期律的关系等5大模块。提出在系统性中突出“玻尔原子模型、核外电子运动状态的描述、4个量子数、核外电子的排布和原子结构与元素周期律的关系”的教学重点;通过提前举办“量子力学基本概念”专题讲座,有利于“量子化的原子结构模型”这一教学难点的突破,并针对每一难点提出了具体的方法措施。提议讲授采用发散思维为主、收敛思维为辅以及有所为有所不为、张弛有度的哲学方法;目的在于通过本章学习后, 使学生在获得基础知识的同时,能学到些许科学的思想方法、学习方法和研究方法。     

Bifurcation of a Main Steady-State Viscous Fluid Flow in a Plane Divergent Channel

The evolution of steady-state viscous incompressible fluid flows in a plane divergent channel is investigated. For the classical formulation of the Jeffery-Hamel problem a complete solution is given as a function of the determining parameters. For a fixed angle of divergence the behavior of the main unimodal flow is determined as a function of the Reynolds number. Critical values at which the flow pattern bifurcates and the steady-state unimodal flow ceases to exist are found. The mechanism of bifurcation is established and its diagram is constructed. This mechanism and the diagram were not previously known in the scientific literature in connection with the investigation of the Jeffery-Hamel problem. The critical Reynolds number at which bifurcation occurs is given as a function of the channel divergence angle. The results may be of interest for hydromechanical, technological, and geophysical applications.__________Translated from Izvestiya Rossiiskoi Academii Nauk, Mekhanika Zhidkosti i Gaza, No. 3, 2005, pp. 25–36.Original Russian Text Copyright © 2005 by Akulenko and Kumakshev.     

O_2（~1△_g）二聚物的兰色激光振荡

通过微波（２．４５０ＧＨｚ）激励高纯氧产生Ｏ２（１△ｇ）二聚物，利用放大自发辐射法首次测得了Ｏ２（１△ｇ）二聚物在４８６ｎｍ处的小信号增益系数。采用平凹稳定谐振腔观察到了４８６ｎｍ的兰色激光振荡，最大激光输出功率为１３０μＷ，发散角为２８ｍｒａｄ。     

Short and Divergent Total Synthesis of (+)‐Machaeriol B, (+)‐Machaeriol D, (+)‐Δ8‐THC,and Analogues

Short and highly efficient stereoselective syntheses provide machaeriols and cannabinoids in a divergent approach starting from a common precursor, commercially available (S)‐perillic acid. Key features of the novel strategy are a stereospecific palladium‐catalyzed decarboxylative arylation and a one‐pot sequence comprising a stereoselective hydroboration followed by oxidation or reduction of the corresponding intermediary boranes. The divergent approach is convincingly demonstrated by the five‐step syntheses of (+)‐machaeriol B, (+)‐machaeriol D, and related analogues, and the four‐step synthesis of (+)‐Δ⁸‐THC and an analogue.     

概率统计课程中研究性学习方法探讨

研究性学习的关键问题之一是充分调动学生主动学习的兴趣与热情,提高学生学习效率,变被动学习为主动学习.结合实例给出了四种激发学生学习兴趣的研究性学习方法,即逆向思维、发散思维、基于Matlab的验证学习以及基于实际问题的教学研究方法.这四种学习方式的有机结合能在理论和实践上有效激发学生主动学习热情及学习兴趣,从而大大提高学生学习效率.     

一种新型激光测距机检测仪

提出在环境应力条件下，室内检测激光测距机性能的专门仪器－激光测距机检测仪，并论述该仪器的构成，设计要点及应用范围。