Influence of steric factors on the direction of reactions

Russian Journal of Organic Chemistry -     

热压铁氧体的制备条件和磁性

本文从实验上研究了起始粉料的制备方法和热压条件对磁头用的Mn-Zn及Ni-Zn热压铁氧体的密度、显微结构和磁性的影响。实验结果表明,化学共沉淀法制备的铁氧体粉料比氧化物法及硫酸盐法制备的要好。适当选择热压条件,可以获得晶粒分布均匀、晶粒大小不同(10μm—300μm)的高密度铁氧体;可以获得μ₀=7420以及B_m=4950Gs的高密度Mn-Zn铁氧体和μ₀等于100—2500的高密度Ni-Zn铁氧体。     

干法显影的电子束抗蚀剂——聚环己烯砜叠氮系

本文研究了用四氟化碳-氧等离子体进行干法显影的电子束刻蚀技术。负型电子束抗蚀剂是由聚环己烯砜和2,6-双-(4'-叠氮苯亚甲基)-4-甲基环己酮组成,其灵敏度为1.5×10^-5C/cm²,分辨率小于1μm,反差约1.43。并讨论了干法显影的影响因素和机理。     

钕玻璃的光泵感应热畸变

本文对钕玻璃的光泵感应热畸变作了理论分析,给出了光泵感应热畸变与钕玻璃热光性质的关系,并对高重复率脉冲器件和单次脉冲器件作了热畸变的定量测量,实验结果在一定程度上与理论分析相符。     

三丁胺胺化强碱性阴离子交换树脂催化苯乙腈的α-丁基化反应

以大孔型苯乙烯系三丁胺胺化强碱性阴离子交换树脂为催化剂，催化苯乙腈的α-丁基化反应，研究了反应温度，催化剂用量和反应时间等因素对反应产率的影响。并考察了催化剂的重复使用性能，结果表明：在优化条件下，该催化剂催化苯乙腈的α-丁基化反应产率高达88%以上，且催化剂具有良好的重复使用性能。     

THE HAUSDORFF MEASURE FOR THE SAMPLE PATH OF THE WESTWATER PROCESS

91.IntroductionTheso-calledWestwaterprocessisthecoordinateprocessunderthepolymermeasureu(g)in3-dimensionsconstructedbyWestwater(see[7,8]),andthepolymermeasurev(g)onCo([O,1]-R')isformallydefinedbywhereC,isthenormalization,gE[o,oo)isacouplingconstant,pistheWienermeasureonCo([o,11-R').Inarecentpaper(see[9]),weprovedthattheHausdorffdimensionofthesamplepathoftheWestwaterprocess{X,,t6[O,1]}isalsotwowithprobability1tou(g).Actually,weprovedin[9]thatgh(ImX)5C,y(g)-a.e.(1.1)m(ImX)5C,y(g)-a.e.(1.…     

一种新型亲水性胺基羧酸树脂的合成及其性能研究

以交联聚甲基丙烯酸缩水甘油酯为起始聚合物，经氨解和氯乙酸化反应，制得了一类骨架结构与聚甲基丙烯酸羟乙酯类似的亲水性胺基羰酸树脂，研究了这类树脂对Cu^2 的吸附性能，发现这类树脂对Cu^2 的吸附量可高达1.78mmol/g，且可以重复使用。     

Pressure-driven "molecular metal" to "atomic metal" transition in crystalline Ga

We present the ultrasonic study of gallium (Ga I) under high pressure up to 1.7 GPa, including the measurements of the density and elastic properties during phase transitions to Ga II and to a liquid state. The observed large drop of both bulk and shear moduli (by 30% and 55%, correspondingly) during the phase transition to Ga II, as well as the increase of the Poisson's ratio from typically "covalent" ( approximately 0.22) to "metallic" ( approximately 0.32) values, experimentally testifies to the coexistence of a molecular and metallic behavior in Ga I and to the disappearance of the "covalency" during the transition to Ga II. A high value of the pressure derivative of the bulk modulus for Ga I and the increase in the Poisson's ratio can be associated with the weakening of the covalency in compressed Ga I and considered as a precursor of the transition to normal metal.     

THE SYMMETRY OF STRATONS IN

In this paper,the color symmetry of stratons for a theoretical model proposed some times ago is investigated.This symmetry contains two kinds of transformations, the first is color gauge transformations which leave the color mumber of stratons conserved,the second is color permutations which indicate the equivaluence of dif- ferent color stratons.The structure of this symmetry group（S3α）is investigated.The irreducible representations（IR's）of S3α and the reduction of their direct product are given.The relation between IR's of S3α and those of color U（3）group is discussed. In a simplest physical model only two neutral vector gluons are needed and the super-strong ihteraetions among stratons exhibit saturation properties similar to but somewhat different from the case of the Han-Nambu model.Not only the color singlet, but also other color neutral states belonging to IR's 2 or 1 of S3α all belong to the lowest energy level of the super-strong interactions.If there were eight degenerate vector gluons belonging to IR's 2 and 6,the Han-Nambu model would be reproduced.