WATER-BLOWN POLYURETHANE RIGID FOAMS MODIFIED BY CHEMICAL PLASTICATION

1. INTRODUCTIONThese years, HCFC-141b may be the most used blowing agent for its useful properties. But, because of its high global warming effect leading to the destruction of the ozone layer, production of HCFC141b has been forbidden. However, there are…     

1,3,4,6-四-O-乙酰基-β-D-氨基葡萄糖的合成

分别用对甲氧基苯甲醛和苯甲醛保护D-氨基葡萄糖的氨基，再将羟基用乙酰基保护，以氯化氢脱去氨基上的保护基团，最后脱去氯化氢得到1，3，4，6-四-0-乙酰基-β-D-氨基葡萄糖。两种方法的总产率分别为59％和61％。道关键中间体3b未见报，其结构经^1H NMR表征。     

SYNTHESIS, STRUCTURE AND PROPERTIES OF INTERPENETRATING SULFONIC ACID RESINS WITH HIGH CAPACITY

Two series of interpenetrating sulfonic acid resins (ISAR), 10×n and n×10, were prepared by means of the wet method, and the physicochemical, thermodynamic and kinetic properties of the ISAR were measured. The results show: 10×n resins exhibit better properties than n×10 ones, mainly in higher apparent degree of crosslinking and larger conformational entropy effect, among which, 10×1 resin exhibits the best thermodynamic and kinetic properties. In the DTA graphs of n×10 resins, there are two T_g and two T_(ox), but in those of 10×n, only one T_g and one T_(ox). This result well supports the conclusion that 10×n resins have much better interpenetrating structural aspects.     

电化学方法对两性接枝星形聚合物LB膜屏蔽效应的研究

本文将自制Y式玻碳电极拉上两性接枝星形聚合物(GPSMA)的LB膜,用循环伏安法研究谈膜的屏蔽效应,讨论了接枝量、成膜条件等对膜缺陷的影响,并提出了减少缺陷的办法。     

NMR SPECTROSCOPIC STUDY ON COPOLYMER OF ETHYLENE-NORBORNENE

A series of ethylene-norbornene copolymers were synthesised using VO (OEt) Cl_2/Al_2Et_3Cl_3 catalytic system and their structure was characterized by ~1H-NMR, ~1H-~1HCOSY NMR and ~(13)C-NMR. Assignments of NMR spectra were given and discussed indetail.     

O-烷基-O-(2′-甲酰缩氨基硫脲苯基)-N-烷基硫代磷酰胺的合成(一)

本文报道了O-烷基-O-(2′-甲酰缩氨基硫脲苯基)-N-烷基硫代磷酰胺类化合物的合成方法,化合物3c和3e具有良好的除草活性。     

Rapid—In—situ Determination of Chromium （VI） in Water Using Modified Diphenylcarbazine with Citrate

In recent years, the determination of Cr (VI) has attracted great attention because of its toxicity to human, plants and animals1-5. Usually, in the industrial waste water, the concentration of Cr (VI) is relatively high and should be determined frequently. So, an accurate, quick, and convenient method for the measurement of Cr (VI) in environmental water, as well as in river, lake, sea and tap water, is of great importance. The method for determination of Cr (VI) by diphenylcarbazine …     

ELECTRON PARAMAGNETIC RESONANCE STUDIES OF SINGLE CRYSTAL SODIUM HEXAMOLYBDOCHROMATE (Ⅲ)Cr~(3+)/Na_3(AlMo_6O_(24)H_6)·8H_2O

An X-band EPR study on a Na_3(CrMo_6O_(24)H_6)·8H_2O single crystal diluted by its isomor-phic compound Na_3(AlMo_6O_(24)H_6)·8H_2O at room temperature is reported. Using the least squares-fitting method to simulate the EPR data for principal planes, the Hamiltonian parameterswere obtained. The principal values of the g tensors are g_(ZZ) = 1.904, g_(XX)= 1.973, g_(YY)=1.933. The zero field splitting tensor parameters are D = 0.275 cm~(-1), E = 0.05 cm~(-1). The fielddependence of Cr~(3+) energy levels with field at different angles from the principal axes whenthe field is along the principal planes is calculated based on these experimental parameters.The isofrequency plots of calculated field vs. angle are also shown. They agree well with theexperimental results.     

两种计算吸光光度法同时测定钙镁

研究了在pH10．5的硼砂-氢氧化钾缓冲溶液和乙醇的增敏作用条件下，偶氮氯膦Ⅰ与钙、镁的吸收特性，建立了多波长光度法同时测定钙和镁的方法。采用两种矩阵算法对试验数据进行处理，并对结果进行比较和分析。钙和镁含量在0～25μg／25ml范围内用计算法Ⅱ能得到准确结果。     

人参中总皂甙的超声波快速提取方法研究

建立了人参中总皂甙超声波半微量快速提取方法，与索氏提取法相比，此法提取时间由索氏法的1－2个工作日缩短到30min，节省大量试剂，综合提取效率提高数十倍，与索氏提取法对照分析表明，此法可完全满足人参中总皂甙的快速测定要求。