以Na2S2O4为还原剂光度法测定废水中硝基苯

对废水中硝基苯的分光光度测定法进行了改进。提出在碱性介质中,以连二亚硫酸钠(Na2S2O4)为还原剂将硝基苯还原为苯胺,经重氮化后与N (1 萘基) 乙二胺盐酸盐偶合生成紫红色化合物,其最大吸收波长为552nm,测定范围为0～2.4mg/L,摩尔吸光系数为3.36×104L·mol-1·cm-1。     

一种用于大容量逆流色谱制备的立式多层螺旋管行星式离心机

Owing to no complications caused by solid supports, such as adsorptive sample loss and deactivation, tailing of solute peaks, and contamination, countercurrent chromatography (CCC) has been an area of intense research since the first introduction of CCC in 1970,[1] and various apparatus and broad applications have been advanced[2,3]. For these developments, the type-J synchronous planet centrifuge has received considerable attention, which relies not only on its relatively simple mechanic design, but also on its high partition efficiency and short elution time caused by mixing and settling for the efficient chromatographic separations. In the past, however, almost all of type-J centrifuges rotated slowly were disposed horizontally due to the original design and some experiments that gravis plays an important role at a low rotary speed as similar to type-V rotating multilayer helical tube in unit gravity[4-9]. In fact,we discovered that the upright apparatus holds more retention of stationary phase than the horiziontal aparatus when large standard tubings were used as mutilayer coil column and the aparatus was operated under same contions. We report here a new coil planet centrifuge with four upright cylindrical columns for large scale countercurrent chromatographic preparation. The design principle and apparatus of UCCC is as samilar to type-J multilayer coil planet centrifuge. Four uptight cylindrical column holders are symmetrically arranged around the centrifuge axis as similar to the type-J HSCCC with three horizontal multilayer coils connected in series[8] . A series of experiments indicat that upright CCC has many advantages over the horizontal CCC when using a large-bore tube as multilayer coil column for large scale countercurrent chromatographic separation.Upright CCC provide a versatile countercurrent chromatographic method for large-scale preparation from very crude sample. It has good preparative capacity and flexible suitability to various sample and two-phase system.The present apparatus not only can be operated at a high speed as similar as commonly used HSCCC for the system having short settling time and but also can be run at a low speed for the system having relative long settling time. Because of automatical control and seal-free flow through device, the uptight CCC apparatus may be readily scaled up to industrial preparation.     

R基团搜索技术用于硼酸三肽蛋白酶体抑制剂的分子设计

本文采用Topomer CoMFA对44个Tyropeptin硼酸三肽类蛋白酶体抑制剂进行三维定量构效关系(3D-QSAR)分析。所得最优模型的拟合、交互验证、及外部验证的复相关系数分别为0.983、0.651、0.963。采用Topomer search对ZINC数据库进行R基团的虚拟筛选,得到具有特定活性贡献的R基团,以活性最高的分子为模板过滤,得到7个R1和5个R2基团。并以此设计得到活性优于模板分子的20个新化合物。结果表明,所建立的Topomer CoMFA模型具有良好的稳定性和预测能力,基于R集团的Topomer search技术可以有效筛选,并为设计出新的蛋白酶体抑制剂提供理论依据。     

一种高灵敏、多响应的Zn-MOF荧光传感器对Fe3+、2，4，6-三硝基苯酚和奥硝唑的检测

在水热条件下基于H₄bta(1,2,3,5-苯四酸)和bpy(4,4''-联吡啶)配体设计、合成了一个锌的金属有机骨架(Zn-MOF){[Zn₂(bta)(bpy)(H₂O)₂]·H₂O}_n(1),并用元素分析、红外光谱、X射线单晶衍射等对其进行了结构表征。MOF 1为三维网状结构。完全去质子化的(bta)^4-配体采用了μ₆-η¹-η²-η²-η¹螯合桥联配位方式。有意思的是,MOF 1是一种高灵敏度、选择性好、多响应的荧光传感器,可用于Fe³⁺、2,4,6-三硝基苯酚和奥硝唑的快速检测。此外还研究了1的热稳定性。     

压电弯曲元的夹层梁解析模型

压电弯曲元是一类传感和作动器件,已得到广泛的应用．基于一阶剪切变形理论发展了压电弯曲元夹层梁解析模型,对梁截面采用统一转角并将耦合电势沿厚度的分布假设为二次函数,进一步修正了横向剪应变对电位移的影响．以弯曲元简支梁自由振动为例进行数值分析,解析模型解与二维精确解相比具有良好的精度,为分析弯曲元动力机电响应提供了良好的解析模型．     

一道预赛试题的妙解

2009年全国高中数学联赛吉林省预赛填空题最后一题如下：题目对空间中有6个点两两连线，用红、黄两种颜色对这些边染色，则同色三角形至少有___个．     

金刚石膜合成条件下的鞘层与等离子体参数分布

本文报导了在用热阴极直流放电等离子体化学气相沉积（通常也称ＥＡＣＶＤ．即电子辅助化学气相沉积）方法合成金刚石的条件下的等离子体密度、电子温度、等离子体空间电位分布及基片附近等离子体鞘结构，并讨论其对成膜的影响．     

Boltzmann方程的奇异扰动解法(Ⅳ)——向非Maxwell分子的推广

将文献中求解具有小Knudsen数的Boltzmann方程的奇异扰动方法推广到非Maxwell分子情形。结果表明,对Maxwell分子所建立的方法及所得的主要结论仍然适用。 关键词：     

准上半连续性不必蕴含上半连续性的例子

<正> 1.命 X,Y 是拓扑空间,多值映象 T:X→2~Y 称为上半连续的(upper semi-continuous),如果对任何 x_0∈X 和任何开集 G(?)T(x_0),存在 x_0 在 X 中的邻域 U(x_0)使得 x∈U(x_0)蕴含 T(x)(?)G.F.E.Browder 证明了下述卓越的不动点原理([1]定理3).定理1 命 K 是局部凸隔离实拓扑向量空间 E 的非空紧致凸集,T:K→2~E 上半连续,使得对每个 x∈K,T(x)(?)E 是非空闭凸集,命δ(K)={x∈K|(?)y∈E,使 x+λy(?)K,(?)λ>0}表示 K 的代数边界.假设对每个 x∈δ(K),存在 y∈K,z∈T(x)和λ>0使得z-x=λ(y-x),那么存在 x_0∈K 使 x_0∈T(x_0).