STUDY ON PREPARATION OF INORGANIC COMPOSITE MEMBRANE AND ITS PROPERTIES FOR HYDROGEN PERMEATION

IntroductionDevclopmcntoftcchniqucsforthcscparationofgascousmixturesisofgrcatimportancetochemicalindustries.Rccentadvanccsinceramicmaterialprocessinghavcstimulatedtheeffortstodcvclopccramicormctallicmcmbrancsforgasseparation.Suchmembraneswouldbesuitableforthescparationsathightemperatureatx`hichthcx`ellcstablishedorganicpol}mermcmbranescannotfunctionButmostcommercialceramicmembranesxvhichcanbcobtainedinmarkctaremicroporous(porediamcterfromO.ItoloPm)whereseparationmcchanismisgovcrncdbyKnudscnd…     

微量元素锌促进儿童生长发育临床研究

报道以微量元素锌治疗缺锌患儿１１８例并与１１４例作对照观察．结果发现，衡量生长发育与营养的敏感指标：身高、体重、血清白蛋白及血色素等参数，治疗组比对照组都显著提高（Ｐ值＜０．０１）．证明锌制剂对缺锌儿童有显著的促进生长发育及改善营养状态作用，作者并对锌的作用机理作了论述．     

BaLaB_9O_（16）中Ce~（3＋）敏化Dy~（3＋）发光的机理

在紫外光激发下，研究了ＢａＬａＢ９Ｏ（１６）中Ｄｙ（３＋）、Ｃｅ（３＋）的发光光谱、激发光谱、发光强度及荧光寿命随着组成变化的规律性．结果表明：Ｄｅ（３＋）对Ｄｙ（３＋）的发光有相当强的敏化作用，Ｃｅ（３＋）→Ｄｙ（３＋）的能量传递效率可高达９３％，能量传递的机理为电偶极－偶极相互作用的共振传递．根据３４９ｎｍ激发下Ｄｙ（３＋）发光强度与浓度的关系，证明了Ｄｙ（３＋）发光的自身浓度猝灭机理也为电偶极－偶极相互作用．     

聚碳酸酯合成工艺开发的新进展

本文从工艺开发的角度，简要评介了目前聚碳酸酯两大工业生产工艺，即光气化界面缩聚工艺和熔融酯交换缩聚工艺的研究开发新动向。     

CnB-的激光等离子体产生与质谱分析

Time-of-flight mass spectrum of C_nB~- has been recorded on a selfbuilt instrument with laser vaporization of tetraphenylboron sodium. By analysis of the com-position of the anions, it is found that number of the boron atoms in any of these ions equals to the number of the charges carried by the anion, and the sum of the numbers of the carbon and boron atoms in these species are always the odd numbers. The experimental results show that boron atom has a strong tendency to attract an electron so that those C_nB~- will have similar electronic structures as C_n, and carbon clusters with odd members are always more stable than their even neighbors.     

Bis(m-phenylene)-32-crown-10-based cryptands, powerful hosts for paraquat derivatives

Four new bis(m-phenylene)-32-crown-10-based cryptands with different third bridges were prepared. Their complexes with paraquat derivatives were studied by proton NMR spectroscopy, mass spectrometry, and X-ray analysis. It was found that these cryptands bind paraquat derivatives very strongly. Specifically, a diester cryptand with a pyridyl nitrogen atom located at a site occupied by either water or a PF(6) anion in analogous complexes exhibited the highest association constant K(a) = 5.0 x 10(6) M(-1) in acetone with paraquat, 9000 times greater than the crown ether system. X-ray structures of this and analogous complexes demonstrate that improved complexation with this host is a consequence of preorganization, adequate ring size for occupation by the guest, and the proper location of the pyridyl N-atom for binding to the beta-pyridinium hydrogens of the paraquat guests. This readily accessible cryptand is one of the most powerful hosts reported for paraquats.     

萃取分光光度法测定废烟末中的尼古丁

本文在ｐＨ４．５的乙酸－乙酸钠缓冲溶液中，使烟碱与甲基橙生成稳定的黄色络合物，然后用二氯甲烷萃取。于λｍａｘ＝４３５ｎｍ处测定有机相的吸光度，烟碱浓度在０－６５μｇ／５ｍＬ范围内符合比尔定律，摩尔吸光系数为９．８％１０＾３Ｌ．ｍｏｌ＾－＾１．ｃｍ＾－＾１。方法快速，简便，应用于烟草中烟碱的定量分析，其加标回收率在８１－１０９％之间，相对标准偏差小于４．１％。     

PA.FPNS: its synthesis and use in spectrophotometric determination of magnesium

A new polymeric chromogenic reagent PA.FPNS has been synthesized by condensing polyallylamine (PA) with 3-(4-formylphenylazo)-4,5-dihydroxynaphthalene-2,7-disulfonic acid (FPNS) and its properties studied. In alkaline media, PA.FPNS reacts with magnesium to form a water-soluble blue complex, whose absorption maximum is at 604 nm. The molar absorptivity (varepsilon) of the complex is 5.2 x 10(4)l mol(-1) cm(-1), which is four times that of the FPNS-Mg complex, and Beer's law is obeyed over the range 0-0.35 mug ml(-1) magnesium. Compared to the corresponding low-molecular-weight FPNS and other chromogenic reagents, PA.FPNS offers considerably improved sensitivity and selectivity for magnesium, which may be attributed to incorporating FPNS into a water-soluble polymer and the effect of the polymeric chain on the reaction microenvironment. Also, a simple and sensitive spectrophotometric method for the determination of magnesium has been developed and applied to water and human fluid samples with satisfactory results.     

Oligodeoxyribonucleotide analogues with bridging dimethylene sulfide,sulfoxide, and sulfone groups. Toward a second-generation model of nucleic acid structure

Short DNA analogues with bridging dimethylene sulfide, sulfoxide, and sulfone groups replacing the phosphate diesters (S-DNAs) were synthesized from building blocks prepared via two routes, both starting from D-glucose. Building blocks for RNA analogues were prepared by stereoselective introduction of nucleobase into a 2'-acylated ribose analogue. The ribose analogues were converted to deoxyribose analogues by replacement of a 3'-OH group by a thioacetyl unit, followed by photolytic deoxygenation or radical-based 2'-deoxygenation. DNA analogues joined via CH(2)(-)S-CH(2) units were prepared by S(N)2 displacement of a 6'-mesyl group on one building block using a thiolate nucleophile of another. 4,4'-Dimethoxytrityl protection and deprotection schemes were established for both the thiol and hydroxyl groups. The corresponding sulfoxide DNA analogues were obtained by oxidation with hydrogen peroxide. Sulfone DNA analogues were obtained by oxidation of the sulfide DNA with persulfate or hydrogen peroxide in the presence of a titanium silicate catalyst. The physical properties of several representative oligonucleotide analogues were examined, and interpreted in light of a "second-generation" model for DNA strand-strand recognition, a model that emphasizes the role of the polyanionic backbone in diminishing unwanted tendencies of highly functionalized molecules to form "structure" in solution. Even short sulfide-linked DNA analogues displayed association properties different from those displayed by standard DNA molecules. Complex formation observed with sulfide-linked tetramers by HPLC study in different solvents suggested that the complex is formed using hydrogen bonding. Sulfone-linked dinucleotides display Watson-Crick behavior; the tetramer, however, displayed self-structure. Self-structure and self-aggregation become more prominent as the length of the oligonucleotide analogues increases. The tendency to self-aggregate can be decreased by adding a charged sulfonate group to the 3'-end of the DNA analogue. Features of the second-generation model are important for many areas of nucleic acid chemistry, from the design of nucleic acid therapeutic agents to the search for life on other planets.     

Synthesis and photophysics of one mononuclear Mn(III) and one dinuclear Mn(III,III) complex covalently linked to a ruthenium(II) tris(bipyridyl) complex

The preparation of donor (D)-photosensitizer (S) arrays, consisting of a manganese complex as D and a ruthenium tris(bipyridyl) complex as S has been pursued. Two new ruthenium complexes containing coordinating sites for one (2a) and two manganese ions (3a) were prepared in order to provide models for the donor side of photosystem II in green plants. The manganese coordinating site consists of bridging and terminal phenolate as well as terminal pyridyl ligands. The corresponding ruthenium-manganese complexes, a manganese monomer 2b and dimer 3b, were obtained. For the dimer 3b, our data suggest that intramolecular electron transfer from manganese to photogenerated ruthenium(III) is fast, k(ET) > 5 x 10(7) s(-)(1).