双[1,3-二苯基-2-咪唑烷叉]和几种卤代烷的自由基型反应

在促进自由基型反应的条件(紫外光照射、无溶剂、室温振荡48小时)下,双[1,3-二苯基-2-咪唑烷叉](Ⅰ)与过量四氯化碳反应后生成较复杂产物(转化率约24%),自其中可分离检定二氯化物Ⅲe(约39%),一氯化物Ⅳ(约15%)及少量六氯乙烷.双体Ⅰ与1-氯丁烷反应(转化率约11%),亦可得二氯化物Ⅲe(约52%).同样,自过量1-溴丙烷可得二溴化物Ⅲd(产率约59%,反应转化率约29%),自过量碘乙烷可得二碘化物Ⅲb(产率约70%,反应转化率约41%).在离子型或异裂性的反应条件(室温、乙腈溶液、无引发自由基因素)下,各卤素与双体Ⅰ迅速反应,并以100%转化率及高产率形成其相应二卤化物Ⅲ.计:二氯化物Ⅲe,产率98%;二溴化物Ⅲd,产率90%;二碘化物Ⅲb,产率90%.新化合物Ⅲe及Ⅲd的结构通过几近定量的化学转化、紫外吸收光谱的对比、不同方法合成同一产物的熔点及混合烷点的对比以及元素分析得到证明.本工作说明,双体Ⅰ的反应方式不仅限于作为亲核卡宾Ⅱ的来源.双体Ⅰ本身是活泼分子,既能参与离子型反应,也能参与自由基型反应.     

交流示波极谱滴定的研究——Ⅱ.用铬酸钾滴定常量铅

在前文^[1]中,作者以EDTA滴定镓的络合反应为例,说明交流示波极谱滴定可应用于常量分析,准确度符合一般容量分析的要求。本文报告以铬酸钾滴定铅。实验结果表明:对沉淀反应而言,交流示波极谱滴定也可应用于常量分析,准确度符合一般容量分析要求。     

DIMENSIONAL METHOD TO SOLVE THE DIFFUSION CONVECTION EQUATION OF SOLAR COSMIC RAYS

Physical processes of the propagation of the solar cosmic rays in the interplanetary space include the diffusion in interplanetary disordered magnetic fields and the convection in solar winds. Dimensional method can be applied to solve those equations convertible into Bessel equation, the results obtained are identical with those solved by the commonly used separate variable method. In order to derive an analytic solution to the diffusion convection equation in an unbounded, uniform medium, two dimensionless parameters reflecting the diffusion and convection characteristics of the particles are introduced. In the diffusion dominated case, the solution is similar in form to the diffusion of a source moving with the convection velocity and is modified by another convection term, which can be expanded into a power series of the convection parameter with coefficients composed of the generalized hypergeometric function series of the diffusion parameter. This solution has a clear physical meaning, and can suitably be used in the discussion of the rise phase characteristics of the solar cosmic rays from medium to high energies （E_p≥10¹ MeV）.     

基于晶体生长法的磁性石墨化碳黑的制备及在茶叶农药残留检测中的应用

基于晶体生长法制备了一种均匀稳定的四氧化三铁负载石墨化碳黑磁性纳米材料(GCB/Fe3 O4),通过扫描电镜、傅里叶变换红外光谱仪、X射线衍射仪和振动磁强计对GCB/Fe3 O4的表面形貌、晶体结构、磁学性能进行了分析,并以儿茶素、姜黄素、槲皮素、叶绿素铜钠和β-胡萝卜素为对象,研究了GCB/Fe3 O4对色素、多酚等...     

Klein-Gordon方程初达值问题的一个新的守恒差分格式

本文对非线性Klein－Gordon（NKG）方程的初边值问题提出了一种新的差分格式,它保持了NKG方程初边值问题的能量守恒．证明了该格式的收敛性和稳定性．特别地,由于该格式是完全隐式的,故对求长时解有着重要的作用．数值计算结果表明该方法计算速度快,精度好．     

α-羟基-α-烷基苯乙酮引发MMA光聚合的研究

本文研究了两种α-羟基-α-烷基苯乙酮类的光敏引发剂(α-羟基-α,α-戊撑-苯乙嗣I^-184和α-羟基-α,α-二甲基-对-异丙基-苯乙酮D-1116)引发MMA光聚合的反应。结果表明,它们具有和安息香醚类相类似的效果,聚合速度R_p和引发剂浓度的0.4次方成正比,K_p/K_t^1/2值为0.054(I^-184)和0.053(D-1116),而溶剂极性的影响很小。这类光敏引发剂适用于引发丙烯酸酯类的光聚合反应,并具有色稳定性好的优点。     

ON THE EFFECTIVE LAGRANGIAN FOR THE PURE SUPER YANG-MILLS THEORY DERIVED FROM RENORMALIZATION GROUP CONSIDERATIONS

Further comments and analysis are made on the derivation of the effective Lagrangian for the N=1 pure super Yang-Mi11s theory from renormalization group considerations and on the implications of results obtained.     

CALCULATION OF THE NUCLEAR FISSION BY NUMERICAL SOLUTION OF F-P EQUATION

In this paper, the two-dimensional Fokker-Planck Equation is exactly solved by means of the numerical method. The velocity distribution at the saddle point, the second moments of the coordinate and velocity, and the time development of the nuclear fis-sion rate are studied. The maximum fission rate at a certain viscosity is exhibited by studying the dependence of the fission rate on the nuclear viscosity.     

克拉霉素酚性糖苷衍生物的合成

以克拉霉素为起始原料,经脱克拉定性糖、2′-OH选择性酰化和脱乙酰基反应得到2′-O-对羟基苯甲酰基-3-羟基-克拉霉素中间体,继续在相转移催化的条件下,通过酚羟基Koenigs-Knorr糖苷化反应,合成了克拉霉素2-氨基葡萄糖糖苷化衍生物、半乳糖苷化衍生物和葡萄糖苷化衍生物,总收率为50～60％.所有产物结构经NM...