液晶聚酯与环氧嵌段共聚物的合成及表征

近年来 ,人们利用高分子液晶作为热固性环氧树脂的改性剂 ,不仅可以提高环氧树脂的韧性和强度 ,而且可以改善其热性能 ,为制备高性能的环氧树脂提供了一条新的途径[1,2 ] .目前报道所使用的液晶聚合物大多为液晶聚酯[3 ] 或液晶性聚氨酯[4] ,这些液晶聚合物与环氧树脂由于存在相容性不好的问题 ,给其实际应用带来了困难 .为了改善二者的相容性 ,本文采用溶液法合成了末端带有反应活性基团的聚酯型液晶聚合物 ,将它再与双酚Ａ环氧预聚物反应 ,制得了高分子液晶环氧嵌段共聚物 ,其合成路线如下 :2ＨＯＣＯＯＣＨ3+ ＨＯ(ＣＨ2 ) 6 ＯＨ　　Ｈ…     

SPECIFIC PROTEIN OCCURRENCE RELATED WITH PHOTOPERIODIC FLOWER INDUCTION IN THE COTYLEDONS OF Pharbitis nil CV. VIOLET

In our experiment, three groups of seedlings of SDP Pharbitis nil cv. violet were sepa-rately treated with three different photoperiods (1,16 h dark period--SD; 2, continuous illumi-nation--CL; 3, 16 h dark treatment with 10 min white light in the middle of the dark period--NB). By analysing proteins in the cotyledons from three groups with 2-D PAGE, we found nodifference in protein pattern between the three groups at 0 or 8 h after photoperiodic treatments.At 24 h after the treatments, a specific protein(MW:19 kD; pI: 4.5)appeared only in the cotyledonsof the seedlings which endured SD. This protein disappeared at 72 h after SD. ActinomycinD could inhibit flowering and the specific protein occurrence when applied to cotyledonsprior to SD, but it had no inhibition effect on flowering as well as the specific proteinoccurrence when applied to cotyledons after SD. Chloroamphenicol, a protein synthesisinhibitor, inhibited flowering when applied to cotyledons prior to or immediately after SD,but it did not i     

一例可分离的双核铁氢自由基阳离子

成功分离得到了一例双核铁氢自由基阳离子盐cis-[Fe₂Cp₂（μ-H）（μ-PPh₂）（CO）₂]^·+[Al（OC（CF₃）₃）₄]^-（cis-1^·+[Al（OC（CF₃）₃）₄]^-）晶体，并使用单晶X射线衍射、电子顺磁共振、红外光谱、紫外-可见光谱以及密度泛函理论对它进行了表征和理论计算。电子顺磁共振和密度泛函理论计算分析表明，自由基的自旋密度主要均等分布于2个铁原子上。     

纳米钯粒子的超声制备与表征

Monodispersed nano-Pd particles were prepared by sonochemical reduction of a 1∶12 molar mixture of palladium(Ⅱ) chloride(PdCl₂), and sodium dodecyl sulfate (SDS) in double deionized aqueous solution. The reducing substance was characterized by transmission electron microscopy (TEM) with selected area electron diffraction (SAED), Fourier transform infrared (FTIR) and X-ray photo electron specstropy analysis (XPS). The results show that the reduction of Pd(Ⅱ) to metallic Pd is achieved and that the obtained suspensions have a long life period. The Pd nanoparticles are highly dispersed and uniform in size (in the range of 1～10 nm). The protective effect of SDS for Pd nanoparticles was investigated and the results indicate that there are interactions between Pd and SDS.     

高比表面积窄孔分布氧化铝的制备研究 Ⅰ.沉淀条件的影响

 以硫酸铝液为原料，以氨水、氢氧化钠和铝酸钠为碱沉淀剂，采用pH摆动法制备了高比表面积、大孔径、窄孔分布、大孔体积氧化铝，考察了沉淀剂、沉淀温度及沉淀时酸侧pH值对氧化铝物性的影响，并对pH摆动法与等pH沉淀法的结果进行了比较．结果表明，通过改变制备参数可以获得高比表面积、大孔体积的氧化铝，当沉淀温度为70℃，pH摆动3或4次时，氧化铝的孔体积可高达1．0ml／g，比表面积仍大于300m2／g．用pH摆动法制得的样品比用等pH沉淀法制得的样品容易酸溶，对挤压成型有利．不同样品在酸溶液中的分散性表明，用氨水沉淀剂可获得相对较小的沉淀粒子．改变沉淀时酸侧的pH值，可导致沉淀粒子的结构发生变化．     

白杨素-6-磺酸钠及其Zn(Ⅱ)、Ca(Ⅱ)配位化合物与NDA作用的研究

采用紫外、荧光、粘度法研究了白杨素-6-磺酸钠、白杨素-6磺酸双核锌及白杨素-6-磺酸四核钙与小牛胸腺DNA的结合常数分别是KNa=1.52×104L.mol-1、KZn=3.56×104L.mol-1和KCa=1.54×104L.mol-1。实验结果表明,白杨素-6-磺酸双核锌和白杨素-6-磺酸四核钙;白杨素-6-磺酸钠与DNA间的作用方主要为静电结合。     

环氧烷化合物在有机合成中的应用

综述了近年来环氧烷化合物在有机合成中的应用。环氧烷化合物的开环反应可以用来合成其它方法难以合成的多官能团化合物，或通过开环和修饰合成其他环状化合物。另外，利用该反应还可以提供保护基以及立体、区域选择性地合成各种有机化合物。参考文献23篇。     

毗邻沙漠地区微分博弈模型与宏观环境治理策略研究

工业化发展导致了脆弱的土地进一步沙漠化,沙漠地区政府应综合考虑经济发展与土地沙漠化导致的生态质量降低。通过构建两个沙漠化地区微分博弈模型,研究了两个地区的沙漠治理问题。研究结果表明,提高工业生产排放技术或沙漠治理技术均能够提高均衡经济产出水平,在工业生产收益系数较高的情况下也能够提高沙漠治理投入水平,并且两种技术提高存在交互效应;只有对生产排放技术水平和沙漠治理技术水平较高的地区,延长地方政府领导任期有利于沙漠治理;实现沙漠完全治理情况下控制土地再沙化的治理投入低于控制沙漠稳定在一定规模的治理投入。     

Isolation, Mapping, DNA Sequence and RFLPs Studies of Random Single-Copy DNA Segments on Human X Chromosome

Using the total human/mouse DNA as the probe, screening has been carried out three times with in situ plaque hybridization to obtain the single-copy DNA sequence from the human X chromosome genomic library. The effective rate of screening is 1. 45%. DNAs from clones containing single-copy inserts have been analyzed by a panel of hybrid cells with or without human X chromosome. Three segments, designated by DXFD52,73,75, are mapped to the X chromosome. DXFD52 has been precisely localized on Xq12-q13 with in situ chromosomal hybridization. DXFD52 has been partially sequenced. The results indicate that DXFD52 is a new isolated single-copy segment on the X chromosome. Great progress in the RFLPs study with DXFD52 has been achieved in the population of Chongqing, Sichuan Province. The results show that the DXFD52 can be used to detect the RFLP with Hind Ⅲ, Bgl Ⅱ, and Hinf Ⅰ. DXFD52 will be a potential "landmark" for the construction of the complete linkage map of human genome and the analysis of genomic s     

Two New Pyrrolizidines from Ligularia lankongensis

Two new pyrrolizidines named lankongensisine A (1), B (2) were isolated from the roots of Ligularia lankongensis collected in Lijiang, Yunnan, and their structures were established by spectroscopic analysis.