Dual Si-H effects in platinum-catalyzed silane reduction of carboxamides leading to a practical synthetic process of tertiary-amines involving self-encapsulation of the catalyst species into the insoluble silicone resin formed

Combination of commercially available platinum catalysts with siloxanes containing more than two Si-H groups is found to be an efficient catalyst system for the reduction of carboxamides to amines. In particular, facile removal of silicon and platinum residues from the product can be achieved by the use of polymethylhydrosiloxanes as reducing reagents.     

A hybrid genetic algorithm-heuristic for a two-dimensional orthogonal packing problem

In this paper we address a two-dimensional (2D) orthogonal packing problem, where a fixed set of small rectangles has to be placed on a larger stock rectangle in such a way that the amount of trim loss is minimized. The algorithm we propose hybridizes a placement procedure with a genetic algorithm based on random keys. The approach is tested on a set of instances taken from the literature and compared with other approaches. The computation results validate the quality of the solutions and the effectiveness of the proposed algorithm.     

A 3D-BPP approach for optimising stowage plans and terminal productivity

This paper addresses the problem of determining stowage plans for containers in a ship, that is the so-called master bay plan problem (MBPP).     

k-边覆盖对策及其核心

本文针对从图的k-边覆盖问题引出的合作对策模型，利用线性规划对偶理论得到了其核心非空的一个充分条件和构造核心分配的多项式时间算法，并将这一结果推广到了一般的k-集合覆盖对策模型中．     

双波长分光光度法同时测定岩石矿物中的微量金和钯

本文提出以硫代米蚩酮为显色剂，用双波长分光光度法同时测定岩石矿物中的微量金和钯的方法，消除了测定金钯的相互干扰，该方法简便，快速，选择性好，用于矿石样品中金和钯的测定，结果满意。     

Convergence of optimal stochastic bin packing

Consider independent identically distributed random variables (X_i) valued in [0,1]. Let B(n) be the optimal (minimum) number of unit size bins needed to pack n items of size X₁, X₂,…,X_n. We prove that there exists a numerical constant C such that for t > 0,

$\text{Pr(∣B(n)?E(B(n))∣>t}\text{n}\text{)≤ C exp(? t).}$

The constant C does not depend on the distribution of X.     

Crystallization of chiral compounds. 1. Spectroscopic,thermochemical, and crystallographic investigation of homochiral and racemic glycidyl p-toluenesulfonate

Crystalline specimens of homochiral and racemic glycidyl p-toluenesulfonate were studied by IR spectroscopy, differential scanning calorimetry, and X-ray diffraction analysis. The melting phase diagram of glycidyl p-toluenesulfonate was constructed. The stacking effect in the crystals of the racemic sulfonate is responsible for a more dense molecular packing, with the result that a heterochiral type of crystallization becomes more favorable.     

双功能催化剂体系作用下乙烯二聚和共聚合的研究

用乙烯为原料在双功能催化剂体系的作用下通过二聚和共聚合反应，直接合成线性低密度聚乙烯（ＬＬＤＰＥ）．所用二聚反应催化剂为钛酸正丁酯（Ｔｉ（ＯＢｕ）_４），共聚催化剂为ＴｉＣｌ_４／ＭｇＣｌ_２（ＺＭ－１催化剂）．研究了二聚反应动力学行为及影响双功能催化剂体系动力学过程的一些因素．结果表明利用这两种催化剂组成双功能催化剂体系能够很方便地制得密度范围在０．９０－０．９３，Ｅｔ／１０００Ｃ在１０－４０的ＬＬＤＰＥ．     

Copolymer of Di (methacryloyloxymethyl) naphthalene and divinylbenzene as a column packing for high-performance liquid chromatography

Summary A new porous polyaromatic ester packing was synthetized for high performance liquid chromatography. The relationship between retention and chain length of the members of homologous series of alkylbenzenes, N-alkylanilines, alkylarylethers, alkylbenzoates and alkylarylketones on this new stationary phase using different eluents was investigated. Using the alkylarylketone scale the retention indices of the homologues and test compounds were calculated. The results were compared with those obtained for poly (styrene-divinylbenzene) polymers. For both types of packing the first members of each homologous series gave non-linear behaviour. The methylene group index increments are different for the studied homologous series; thus there is no simple additivity of the retention indices. The efficiency of the porous polymeric columns is a function of the capacity factor of the solute and the organic component of the eluent.