Studies on Chemical Constituent of Zizyphus Jujuba in Hebei China

Introduction Jujuba is the fruit of Zizyphus genus(Rhamnaceae) which has been used as a crude drug. Now quite a lot of botanists, chemists and pharmacologists at home and abroad have been deeply interested in the studies on it. Besides the studies on its fruit, a great deal of research work on its other parts has been done So far more     

聚[丙烯酸甲酯-甲基丙烯酸2-(二甲氨基)乙酯]/环氧树脂IPN力学性能的研究

用同步法合成聚[丙烯酸甲酯-甲基丙烯酸2-(二甲氨基)乙酯]/环氧树脂(P(MA-DMA)/EP)互穿聚合物网络(IPN),对其力学性能进行了研究,结果表明,该体系IPN由于两网络间接枝导致相客性比较好,动态力学谱仅出现一个转变温度,当P(MA-DMA)/EP=20/80时,力学性能显示正协同效应,对环氧树脂的增韧效果最佳,不同组成比的IPNT_g实-T_g计与(d_实-d_计)差值成正比。     

Baker-Nathan顺序中烷基的键参数及超共轭本质探讨

用甲基超共轭模型和多电子共轭的经验公式及合理的键积分参数K,计算了Baker-Nathan顺序中烷基的超共轭能,探讨了超共轭的本质。     

微乳液反应法制备聚甲基丙烯酸甲酯超细粒子

水/油微乳液;微乳液反应法制备聚甲基丙烯酸甲酯超细粒子     

H2BPMPBD和HAP协同萃取Ln(Ⅲ)

镧系元素;H2BPMPBD和HAP协同萃取Ln(Ⅲ)     

Sb(Ⅲ)-甲基橙-溴化十六烷基三甲铵的高灵敏显色反应研究及应用

在ｐＨ３．５～４．５的邻苯二甲酸氢钾－ＨＣｌ缓冲介质中,Ｓｂ（Ⅲ）与甲基橙、溴化十六烷基三甲铵形成有色多元配合物的显色反应,建立了测定微量锑的高灵敏光度分析法。配合物最大吸收波长为５４０ｎｍ,表观摩尔吸光系数为４．８９×１０５Ｌ·ｍｏｌ－１·ｃｍ－１,锑的质量浓度在０～１２μｇ／２５ｍＬ范围内符合比尔定律,配合物中Ｓｂ（Ⅲ）与甲基橙（ＭＯ）的组成比为ｎ（Ｓｂ（Ⅲ））∶ｎ（ＭＯ）＝１∶１。采用巯基棉分离,可消除共存离子的影响,提高体系的选择性。已用于铜合金中微量锑的测定,结果满意。     

Simulation of the reaction front propagation during co oxidation on Pt (100) under unsteady-state conditions

Acid tetrabutylammonium salts of Ti(IV)-monosubstituted heteropolytungstate, PW₁₁TiO₄₀ ⁵⁻, show high catalytic acitivity in the oxidation of methyl phenyl sulfide with hydrogen peroxide, while the corresponding tetrabutylammonium salts containing no protons are poor catalysts for this reaction.     

薄层色谱法分析2-丙烯酰胺基-2-甲基丙烷磺酸

应用薄层色谱法对工业品２ 丙烯酰胺基 ２ 甲基丙烷磺酸（简称ＡＭＰＳ）进行了分析,以硅胶ＧＦ２５４作为吸附剂,从几种溶剂系统中优选了Ｖ（苯）∶Ｖ（甲醇）＝２∶１溶液作为展开剂,用２５４ｎｍ紫外分析仪检测展开后的样品斑点。实验表明：ＡＭＰＳ的Ｒｆ为０３６,而其主要杂质丙烯酰胺（ＡＭ）的Ｒｆ为０．６４;ＡＭＰＳ的最小检出限为５μｇ,展开时间约为２５ｍｉｎ。方法简便、快速、重现性好,有利于在生产过程中快速分析ＡＭＰＳ及其所含杂质,从而指导对ＡＭＰＳ的纯化处理。     

Phase Separation in Aqueous Polymer Solutions as Studied by NMR Methods

Some possibilities of ¹H NMR spectroscopy in investigations of structural-dynamic changes and polymer-solvent interactions during the temperature-induced phase transitions in aqueous polymer solutions are described. Results obtained recently on D₂O solutions of poly(vinyl methyl ether) (PVME), poly(N-isopropylmethacrylamide) (PIPMAm), negatively charged copolymers of N-isopropylmethacrylamide and sodium methacrylate, and PIPMAm/PVME mixtures are discussed. A markedly different rate of dehydration process in dilute solutions on the one hand, and in semidilute and concentrated solutions on the other hand, was revealed from ¹H spin-spin relaxation measurements.     

Volatile Organic Compounds from Bacillus aryabhattai MCCC 1K02966 with Multiple Modes against Meloidogyne incognita

Plant-parasitic nematodes cause severe losses to crop production and economies all over the world. Bacillus aryabhattai MCCC 1K02966, a deep-sea bacterium, was obtained from the Southwest Indian Ocean and showed nematicidal and fumigant activities against Meloidogyne incognita in vitro. The nematicidal volatile organic compounds (VOCs) from the fermentation broth of B. aryabhattai MCCC 1K02966 were investigated further using solid-phase microextraction gas chromatography-mass spectrometry. Four VOCs, namely, pentane, 1-butanol, methyl thioacetate, and dimethyl disulfide, were identified in the fermentation broth. Among these VOCs, methyl thioacetate exhibited multiple nematicidal activities, including contact nematicidal, fumigant, and repellent activities against M. incognita. Methyl thioacetate showed a significant contact nematicidal activity with 87.90% mortality at 0.01 mg/mL by 72 h, fumigant activity in mortality 91.10% at 1 mg/mL by 48 h, and repellent activity at 0.01–10 mg/mL. In addition, methyl thioacetate exhibited 80–100% egg-hatching inhibition on the 7th day over the range of 0.5 mg/mL to 5 mg/mL. These results showed that methyl thioacetate from MCCC 1K02966 control M. incognita with multiple nematicidal modes and can be used as a potential biological control agent.