On concepts of directional differentiability

Various definitions of directional derivatives in topological vector spaces are compared. Directional derivatives in the sense of Gâteaux, Fréchet, and Hadamard are singled out from the general framework of -directional differentiability. It is pointed out that, in the case of finite-dimensional spaces and locally Lipschitz mappings, all these concepts of directional differentiability are equivalent. The chain rule for directional derivatives of a composite mapping is discussed.     

Random walks generated by affine mappings

This article is concerned with Markov chains on ^m constructed by randomly choosing an affine map at each stage, and then making the transition from the current point to its image under this map. The distribution of the random affine map can depend on the current point (i.e., state of the chain). Sufficient conditions are given under which this chain is ergodic.     

新的酰胺型开链冠醚的合成与性质

Simon在70年代开发了一类酰胺型开链冠醚,能选择性配位碱土金属离子并可作为中性载体制备离子选择性电极.由于酰胺型开链冠醚易于制备,因此受到人们广泛地重视.Vgtle等提出的“末端基”概念为开链冠醚的合成、设计起了重要的指导作用.前文报道2-甲氧基-1-氨甲基萘与三甘醇二碘化物在无水碳酸钠存在下于乙腈中反应得到双手臂的套索冠醚与碘化钠的配合物.X射线衍射晶体结构分析表明萘环上的甲氧基中的氧原子参加了与钠离子的配位,生成了扭曲的六边形双锥结构配合物.因此2-甲氧基-1-氨基萘可以作为开链冠醚的“末端基”.开链冠醚的合成路线是:     

MONTE CARLO STUDY ON THE CRITICAL ADSORPTION POINT OF BOND-FLUCTUATED POLYMER CHAINS TETHERED ON ADSORBING SURFACES

 The behavior of three-dimensional bond fluctuation model chains tethered on an adsorbing flat surface was simulated by the Monte Carlo method. The dependence of the number of surface contacts M on the interaction strength e and the chain length N was investigated by a finite-size scaling law M = N[a₀ + a₁N^1/v_k + O((N ^1/v_k)²)] for e near the critical adsorption point e_c, i.e., k ≡(e-e_c)/e_c closes to 0. The critical adsorption point was estimated to be e_c = 0.93, and the exponents  = 0.49 and 1/v= 0.57.     

Stereoselective electrocatalytic cyclization of 3-substituted 2,2-dicyanocyclopropane-1,1-dicarboxylic acid esters to form 6-substituted (1R,5R,6R)*-4,4-dialkoxy-5-cyano-2-oxo-3-azabicyclo[3.1.0]hexane-1-carboxylic acid esters

Electrolysis of 3-substituted 2,2-dicyanocyclopropane-1,1-dicarboxylic acid esters in alcohols in an undivided cell in the presence of NaBr or NaOAc afforded 6-substituted (1R,5R, 6R)*-4,4-dialkoxy-5-cyano-2-oxo-3-azabicyclo[3.1.0]hexane-1-carboxylic acid esters in 80–95% yields. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 102–107, January, 2006.     

Detection of processed genetically modified food using CIM monolithic columns for DNA isolation

The availability of sufficient quantities of DNA of adequate quality is crucial in polymerase chain reaction (PCR)-based methods for genetically modified food detection. In this work, the suitability of anion-exchange CIM (Convective Interaction Media; BIA Separations, Ljubljana, Slovenia) monolithic columns for isolation of DNA from food was studied. Maize and its derivates corn meal and thermally pretreated corn meal were chosen as model food. Two commercially available CIM disk columns were tested: DEAE (diethylaminoethyl) and QA (quaternary amine). Preliminary separations were performed with standard solution of salmon DNA at different pH values and different NaCl concentrations in mobile phase. DEAE groups and pH 8 were chosen for further isolations of DNA from a complex matrix-food extract. The quality and quantity of isolated DNA were tested on agarose gel electrophoresis, with UV-scanning spectrophotometry, and by amplification with real-time PCR. DNA isolated in this way was of suitable quality for further PCR analyses. The described method is also applicable for DNA isolation from processed foods with decreased DNA content. Furthermore, it is more effective and less time-consuming in comparison with the existing proposed methods for isolation of DNA from plant-derived foods.     

氰根桥连的异金属配位聚合物{[Ni(pn)2][Fe(CN)4(bipy)]}2·3H2O(pn=1,3-丙二胺,bipy=2,2′-联吡啶)的合成与结构

以[Fe(CN)₄(bipy)]^2-为建筑块和[Ni(pn)₂]²⁺在水溶液中反应,合成了{[Ni(pn)₂][Fe(CN)₄(bipy)]}₂·3H₂O(pn=1,3-丙二胺)。通过X-射线单晶衍射确定了其晶体结构。该配合物属单斜晶系,P2₁/n空间群,晶胞参数为:a     

铝钛合金溴化物对直链烷烃异构化反应的催化作用

首次研究了铝铁合金溴化物的合成及其对直链烷烃异构化反应的催化作用,讨论了正戊烷的异构化反应,得到其动力学方程为1nC/C_0=-0.50t,表观活化能为26.3 kJ/moJ,测定了正己烷、正庚烷、正辛烷在不同溶剂中、不同温度下催化异构化反应的动力学曲线,为铝铁合金溴化物的工业应用提供了理论依据。     

傅立叶变换红外光谱对灰指甲组织结构的研究

对健康指甲和灰指甲的红外光谱特征吸收峰进行了指认,并对其相应官能团的吸收峰进行了对比分析.结果表明,灰指甲增厚、变脆的原因系α-角蛋白螺旋结构遭到破坏,肽链伸展并发生断裂,形成了不同化学环境的氨基酸,同时蛋白质分子的有序排列也发生了改变.