纳米晶MgSO4·5Mg(OH)2·3H2O合成与表征

纳米材料由于具有表面、体积和量子尺寸效应的特殊性而受到广泛重视[1～3]. 微米级硫氧镁晶须作为塑料添加增强和阻燃剂已有报道[4～7]. 纳米晶MgSO4*5Mg(OH)2*3H2O不仅对塑料起补强作用, 而且其粒度小, 使塑料变得更致密, 强度、韧性与防水性能大大提高. 目前纳米材料的合成方法多种多样[8～10], 本文采用水热法制得纳米硫氧镁晶粒, 产物纯度高、分散性好且粒度易控制.     

[Co(ptma)(amp)Cl]2+体系的一反式经式异构体(m3[ZnCl4]·0.5H2O)的晶体结构

在合成[Co(bpma)(tn)Cl]²⁺体系配合物的实验中,得到[Co(ptma)(amp)Cl]²⁺体系的一反式(ptma中仲胺上的氢相对于Cl)经式异构体(m3[ZnCl₄]·0.5H₂O),其中bpma=N,N′-二(2-吡啶基甲基)胺,tn=1,3丙二胺,ptma=N-(2-吡啶基甲基)丙二胺,amp=2-(氨基甲基)吡啶。此配合物异构体构型选择性形成的原因可能主要是其结构中配体间C-H…π相互作用使之更稳定的结果。利用单晶X-射线衍射法测定的晶体学参数:单斜晶系,空间群C2/c,a=1.55978(19)nm,b=1.33324(16)nm,c=2.2077(3)nm,β=94.832(3)°,V=4.5748(10)nm³,D_c=1.696g·cm^-3,Z=8,F₀₀₀=2360,μ(MoKα)=23.72cm^-1,R=0.0475,R_w=0.1204。配合物离子中Co³⁺为六配位。晶胞中含8个配合物阳离子,8个[ZnCl₄]^2-阴离子及4个水分子,对映体的比例为1∶1。     

缩聚合成聚芳酯和聚酯－聚醚弹性体的微相复合物

通过原位直接缩聚反应，制备了刚性棒状聚对羟基苯甲酸酯（ＰＨＢ）和聚对苯二甲酸丁二醇酯－聚四亚甲基醚多嵌段共聚物（ＰＢＴ－ＰＴＭＧ）的微相复合物．复合物可溶于氯仿等溶剂，可以浇铸成膜．本文研究了ＰＨＢ含量和聚合过程中，基体聚合物溶液浓度对微相复合物形态以及力学性能影响．同共混法相比，原位缩聚法可得到分散更均匀，力学性能更优良的微相复合物．     

THE COMPARISON OF LANZHOU LOESS PROFILE WITH VOSTOK ICE CORE IN ANTARCTICA OVER THE LAST GLACIATION CYCLE

Loess near Lanzhou in the late Pleistocene is very sensitive to climatic fluctuations. The Beiyuan terrace profile in Linxia City, of which the curve of susceptibility tallies with the trend of isotopic curves of Vostok 2083 m ice core in Antarctica, is 35m thick. There are five layers of paleosols under Malan loess(L_1). Upper three layers (S_(1-a),S(1-b)and S_(1-c) correspond to three warm stages in last interglaciation, Interstadial of Last Glacial (C stage in Antarctic ice core)was clearly recorded in the Beiyuan profile, in which three layers of paleosols and two of loess were formed. The lowest section of the profile belongs to penultimate glaciation, in which fossils of cold-drought-resistant mammal and mollusc have been discovered.     

ISOLATION,CHARACTERIZATION AND EXPRESSION OF THE COMPLEMENTARY DNA FOR HUMAN TUMOR NECROSIS FACTOR (TNF-α)

A cDNA for human TNF-α (615bp) was isolated by means of polymerase chain reaction (PCR) using first strand cDNA from PMA-induced HL-60 cells as template. The result from sequencing the 615 bp cDNA fragment indicated that it corresponded to the entire sequence of mature human TNF coding region. Direct expression of mature human TNF was achieved using a plasmid pHT-1 constructed by ligation of the cDNA and a synthetic DNA. The IPTG-induced bacterial product (hTNF) showed cytotoxicity to mouse L-929 cells. The TNF activity was further identified by neutralization of a specific monoclonal antibody against human TNF-α. Approximately 80,000 units of activity were detected per ml of culture at A600=2.     

共軛高分子的研究——Ⅲ.苯乙炔的热聚合

研究了苯乙炔在1.5,6和10小时的热聚合过程中温度对聚合物分子量的影响。所得结果表明,在150—500°的温度范围内,随着聚合温度的增高,聚合物的分子量都是逐渐降低,表明在高温时聚合物有裂解现象发生。红外光谱显示,400°所得聚合物的光谱吸收峯较之200°聚合物的为小,500°聚合物则出现无明显吸收峯的连续吸收,并且背景升高(“背景效应”)。聚合物的碳氢含量此同样随着聚合温度的升高而增大。这些结果,以及300°以上聚合物在溶液中显示明显的萤光等,被认为是表明聚苯乙炔在高温时发生结构改变,除裂解成小分子外,可能还有环化、脱氢、芳构化等发生,从而由链状结构变为稠环结构乃至三维共轭结构。 聚合物的电子自旋共振测试表明,聚苯乙炔的自由基浓度随下列顺序递增: 300°聚合物<400°聚合物<500°聚合物。     

Determination of Partial Molar Volumes of EPA and DHA Ethyl Esters in Supercritical Carbon Dioxide

The use of supercritical fluids (SCFs) as solvents has been attracting widespread interest in the research and commercial applications. The study of partial molar volumes of solutes at infinite dilution in the near-critical region is of considerable fundamental importance, as these data reflects the interactions occurring between the solute and the solvent. Experimental measurements of partial molar volumes may be divided into two categories: direct and indirect methods. The direct methods…     

Alkaloids from Fritillaria Hupehensis

Phytochemical investigation of the bulbs of Fritillaria hupehensis resulted in the isolation and structural elucidation of a new highly conjugated alkaloid of veratramine type identified as 3β,23β-dihydroxy-7,12（14）-dien-5α- veratramin-6-one （1）, together with two known alkaloids, ebeinine （2） and zhebeinine （3）, which were isolated for the first time from F. hupehensis. The structures of alkaloids 1-3 were established by extensive 1D and 2D NMR spectral analyses.     

微波辐射下无催化剂一锅法合成N-甲基十氢吖啶-1,8-二酮化合物

为了研究从简单易得的原料在无催化剂的条件下一锅法合成N-甲基十氢吖啶-1,8-二酮化合物，我们以各类醛（脂肪醛、芳香醛、二醛）、达咪酮或1,3-环己二酮和甲胺为原料，以乙二醇或水为溶剂，经微波辐射，一步反应得到了一系列N-甲基十氢吖啶-1,8-二酮化合物。反应时间从传统热反应的4-5小时缩短至2-10分钟，产率较高（56-95%），并且不需要使用催化剂。该反应后处理方便，只需要简单洗涤，环境友好，为合成此类化合物提供了一种简便、有效的合成方法。该方法不仅适用于一元脂肪醛、芳香醛，还适用于芳香二醛，因此可以合成含有一个或两个十氢吖啶结构单元的杂环化合物。     

一种包覆型聚合物高效液相色谱固定相的制备与评价

当代应用最广的HPLC固定相中,硅胶基质填料化学稳定性较低,并且由于残存硅羟基而表现所谓第二效应,特别使碱性化合物的峰形拖尾;聚合物基质填料虽提高了化学稳定性,没有离子基团,但刚性降低,并且由于溶胀难于进行梯度淋洗;面包覆型聚合物填料则可综合二者的优点,本文对我们制备的这种固定相作初步报道。