稀土在机动车尾气催化净化中的应用与研究进展

随着我国机动车尾气排放法规日趋严格,对机动车尾气净化催化剂性能提出了更高的要求.稀土元素由于独特的4f电子层结构和储放氧性能等特性,在机动车尾气催化剂中得到广泛应用.本文综述了稀土元素在机动车尾气催化剂中的应用及相关机理研究现状,并依据京V排放法规要求探讨了最新排放限值对尾气净化催化剂性能的要求,分析了稀土在开发高性能催化剂中的作用,并对稀土在机动车尾气净化催化剂中的应用前景进行了展望.     

1-芳酰基-4-(5-芳基-2-呋喃甲酰基)氨基硫脲衍生物的合成及其生物活性

酰胺基硫脲;芳基酰肼;1-芳酰基-4-(5-芳基-2-呋喃甲酰基)氨基硫脲衍生物的合成及其生物活性     

黄花倒水莲皂甙Reinioside C在大鼠体内代谢产物的鉴定

为了探讨五环三萜皂甙ReiniosideC在大鼠体内代谢产物的结构,单剂量口服ReiniosideC,5h后放血处死,用制备型高效液相色谱方法对血液和各脏器进行提取分离,从大肠内容物和粪中,分离得到了7种代谢产物.用FAB-MS,¹H NMR和¹³C NMR方法鉴定了它们的结构.     

聚苯胺复合材料研究进展

综述了聚苯胺/无机物复合材料和聚苯胺/有机高聚物复合材料的合成方法，性能特征，并展望了聚苯胺复合材料的研究，应用前景。     

磁性聚苯胺纳米微球的合成与表征

报道了具有核壳结构的Fe3O4-聚苯胺磁性纳米微球的合成方法和表征结果.微球同时具有导电性和磁性能.在优化的实验条件下,可得到饱和磁化强度Ms为55.4 emu/g,矫顽力Hc为62 Oe的磁性微球.微球的导电性随着微球中Fe含量的增加而下降.微球的磁性能则随着Fe含量的增加而增大.Fe3O4磁流体的粒径和磁性聚苯胺微球的粒径均在纳米量级.纳米Fe3O4粒子能够提高复合物的热性能.实验表明,磁流体和聚苯胺之间可能存在着一定的相互作用,但这种相互作用较为复杂,难于研究     

完美骨架全硅β沸石性质研究Ⅰ.合成全硅β沸石与脱铝β沸石的性质比较

以四乙基氢氧化铵为模板剂,正硅酸乙酯为硅源,静置水热法合成全硅β沸石.用硝酸(13 mol/L)对硅铝比(Si/Al)为20的Na-β沸石回流脱铝.焙烧后的上述两样品经粉末X射线衍射、低温氮吸附、核磁共振、红外光谱、吸附等温线等表征,发现合成的全硅β沸石骨架与孔道结构完美并具有很高的表面疏水/亲有机物的吸附特性.     

Two Typical Examples of Scaling Ionic Partition Scheme for Estimating Correlation Energy of A2 Type Molecules

Based on the calculation results of pair correlation energy contributions of the various electron pairs in Na2 and H2NNH2 systems and the application of the scaling ionic partition scheme for symmetrical A2 type systems, the total correlation energies of Na2 and H2NNH2 have been reproduced by using this simple scheme. The two results show that the absolute deviations are within an acceptable range of error, however, in this way, more than 90% of computational work can be saved. The most attractive result in present paper is that, in these two molecules the coefficients c1 and c2 in the estimation equation can be obtained by the proportion of correlation energy of A^- to that of A^ singlet system. Therefore, it is believed that the proposed ionic partition scheme for symmetrical A2 molecules would be very useful to estimate the correlation energies of large symmetrical molecules.     

Studies on Natural CXN Zeolite： Modification, Framework De-alumination and Ion-exchange

A natural CXN zeolite (stilbite, type code-STI) discovered in China was modified with NH4^ exchange by using ammonium salt and calcinations (procedure Ⅰ), or with NH4 exchange followed by treatment with acid (procedure Ⅱ). The coordination state of Si and A1 atoms in the framework, the property of ion exchange, and the adsorption of the H-STI zeolite samples prepared by different modification procedure were investigated with XRD,EDX,^29Si and ^27Al MAS NMR, Ag^ ion exchange and Ne adsorption. The results of the investigations indicate that different procedure of the modification made variety on the distribution of the framework Si atoms and A1 atoms,the content of non-framework aluminum, and the blocking channels and the shielding effect to the positions of the exchangeable cations. The H-STI zeolite prepared by the procedure Ⅱ possesses high ion exchange capacity, open and perfect pore system, and high thermal stability.     

MgO/NaY催化糠醛和丙酮合成航空燃料中间体的性能研究

采用"机械混合-焙烧"方法制备了负载型固体碱催化剂MgO/NaY,研究了糠醛与丙酮在水-乙醇体系中的羟醛缩合反应,考察了催化剂负载量、原料配比、反应温度、反应时间等因素对催化剂性能的影响。结果表明,20%MgO/NaY催化剂表现出最佳的催化性能,在85℃条件下反应8 h后,糠醛转化率达到99.6%,亚糠基丙酮(FA)和二亚糠基丙酮(F₂A)选择性分别达到42.2%和57.1%,缩合产物的总收率为98.6%。高温促进反应中间体向产物的转化,有利于提高产物的总选择性。改变糠醛/丙酮的摩尔比可调控两种缩合产物的选择性,较高的糠醛/丙酮摩尔比有利于提高F₂A的选择性,但会降低整体反应速率。重复性评价表明,催化剂具有较好的再生性能。     

食道癌患者血清铜／锌比值及血清硒含量的测定及临床意义

报道了３５例食道癌患者血清铜／锌比值及血清硒水平，结果发现食道癌患者血清铜／锌比值增加，血清硒水平下降，具有显著性差异（Ｐ〈０．００１）；同时提示随着食道癌分期增加，铜／锌比值进一步增加，血硒水平进一步下降，但无统计学差异。上述结果对临床诊断及观察病情变化有一定意义。