过渡金属钼钒砷杂多化合物的合成与TPR,TPD研究

Seven transition metal molybdovanadoarsenic heteropoly compounds have been synthesized and characterized using IR, UV, TG-DTA, pH potential titration techniques. The molecular formulae of these compounds are pro-posed to be H_xM_yAsMO₁₀V₂O₄₀·zH₂O(x=1～3, y=1,2, M=Cr, Mn, Fe, Co, Ni, Cu, Zn).They are all keggin structure. Surface nature of these compounds have been investigated by temperature programmed desorption and temperature programmed reduction techniques. NH₃-TPD results show that in TPD profiles of the compounds there are two desorption peaks corresponding to weak acid sites of desorption, respectively. Desorbing activativon energy and preexponential factor of weak acid site of desorption for compounds have been calculated. H₂-TPR re-sults show that introducting transtion metal to molybdovanarsenic acid, the reduction peak temperatures of H₂-TPR shift regularly with increasing d electron numbers of transition metals. In addition, Zn and Cu heteropoly com-pounds have yet apparent effect of hydrogen spill over.     

试剂加入次序不同造成镉对肝脂质过氧化的诱导或拮抗作用

采用TBA检测方法，体外观察了CaCl2对大鼠线粒体脂质过氧化产物丙二醛(MDA)生成的毒性作用和对半胱氨酸-Fe^2 诱导的线粒体脂质过氧化的影响。结果表明，1 μmol／L～1mol／L CdCl2均能诱导肝线粒体的脂质过氧化，使MDA含量增加，但只有CdCl2浓度高于1 mmol／L时，诱导作用才与对照组有显著性差异。在Fe^2 -Cd^2 半胱氨酸共同对肝线粒体作用时，由于试剂加入顺序的不同，100～1000 mmol／L CdCl2对线粒体脂质过氧化可产生诱导或拮抗作用。结果提示，CdCl2可直接诱导线粒体脂质过氧化，在做几种金属离子体外协同对肝脂质过氧化影响的实验时，应考虑试剂加入顺序所产生的不同影响。     

ADSORPTION OF 2,4-DICHLOROBENZOXYACETIC ACID ONTO HYPERCROSSLINKED RESIN MODIFIED BY PHENOLIC HYDROXYL GROUP (AM-1)

INTRODUCTIONAdsorption has been considered to be the best available technology for removing organics from water in the USSafe Drinking Water Act[1]. Due to many drawbacks of activated carbon[2-7], the most widely used adsorbent,hypercrosslinked polymeric adsorbents developed by Tsyurupa and Davankov[8] have been increasingly viewedas an alternative to activated carbon for selective removal of specific organic substances from contaminatedwater[9-12], and series of researches have been do…     

High-efficiency, environment-friendly electroluminescent polymers with stable high work function metal as a cathode: green- and yellow-emitting conjugated polyfluorene polyelectrolytes and their neutral precursors

A series of aminoalkyl-substituted polyfluorene copolymers with benzothiadiazole (BTDZ) of different content were synthesized by Suzuki coupling reaction, and their quaternized ammonium polyelectrolyte derivatives were obtained through a postpolymerization treatment on the terminal amino groups. Copolymers are soluble in environmentally friendlier solvents, such as alcohols. It was found that the efficient energy transfer occurs by exciton trapping on the narrow band gap BTDZ site under UV illumination. Only 1% of BTDZ content is needed to completely quench a fluorene emission for both the neutral and the quaternized copolymers in the neat film. Absolute PL efficiencies of copolymer films were greatly enhanced as a result of the suppression of excimer formation. Light-emitting devices fabricated from these copolymers show high external quantum efficiencies over 3% and 1% for the neutral precursor and the quaternized copolymers, respectively, with high work function metals such as Al as a cathode. To the best of our knowledge, this is the first report on an electroluminescent polymer which bears the high EL efficiency, the electron-injection ability from high work function metals, and the solubility in environment-friendly solvents at the same time. These features make them a promising candidate for the next generation of light-emitting copolymers in PLED flat panel display application.     

A Minor New Flavone from Scutellaria baicalensis Georgi

A new flavone,6,2′-dihydroxy-5,7,8,6′-tetramethoxyflavone,was isolated from the roots of Scutellaria baicalensis. Its structure was established on the basis of spectral evidences.     

破碎-絮凝法分离细长碳纳米管与碳纤维

根据碳纤维与细长碳纳米管耐磨性能与絮凝沉降性能的差异，提出了一种有效分离细长碳纳米管与碳纤维的物理方法——破碎-絮凝法.该方法包括研磨破碎、液相分散、絮凝沉降、过滤分离等步骤，可高效去除混杂于细长碳纳米管样品中的碳纤维，同时还可去除螺旋状碳纤维及细小碳颗粒等易悬浮杂质.纯化过程对细长碳纳米管无损伤.用电子显微镜和热重分析表征了纯化效果，并初步分析了纯化机理.     

A Novel Plasticizer for the Preparation of Thermoplastic Starch

TPS was a biodegradable material based on starch. Starch was an inexpensive and natural renewable polysaccharide, which was widely investigated as the substitute of petroleum-derived plastics. Native starch commonly existed in granule structure with about…     

氧化锶催化性质：Ⅱ.SrO,MgO上异丙醇的分解反应

ＳｒＯ，ＭｓＯ对异丙醇的分解反应有各自的作用形式，因而产物分布也有明显差别．ＭｇＯ上异丙醇分解，在较低温度时，主要产物为丙酮和丙烯；随温度升高，生成丙烯的量增加，而丙酮的量减少，直至消失，在ＳｒＯ上，异丙醇在较高温度时反应，产物几乎为丙酮，丙烯的生成量极少。认为：产物中丙烯来源于异丙醇在催化剂表面强酸中心上的脱水；丙酮在ＭｇＯ上来源于强碱中心和酸中心协同作用异丙醇的脱氢，而在ＳｒＯ上则是ＳｒＯ表面极强的碱中心作用异丙醇而脱氢制得。     

Two New Xanthone Glycosides from Polygala tenuifolia

Two new xanthone glycosides,polygalaxanthone IV and V were isolated from the roots of Polygala tenuifolia Willd. Their structures were established as 6-O-[α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl]-1-hydroxy-3,7-dimethoxyxanthone(polygalaxanthone IV), and 6-O-[α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl]-1,3-dihydroxyl-7-methoxyxanthone (polyga-laxanthone V),respectively, on the basis of chemical and spectral evidence.