The 1,3-Dipolar Cycloadditions of Nitrile Oxides and Nitrile Imines to Alkyl Dicyanoacetates

The readily available alkyl dicyanoacetates 1 reacted with the 1,3-dipolar reagents arenecarbonitrile oxides 2 ′ and arenecarbonitrile imines 5 ′ to afford 1,2,4-oxadiazol and 1,2,4-triazol derivatives. The arenecarbonitrile oxides 2 ′ with electron-donating groups on the arene ring gave products 3a – d resulting from addition on both CN groups of 1 , and those with electron-withdrawing groups provided mono-adducts 4a – e (Scheme 1). Arylnitrile imines 5 ′ reacted with 1 to offer both bis- and mono-addition products (Scheme 2); the bis-adducts 8a , b possess an ester structure, whereas the mono-adducts 6a – d present a ketene-hemiacetal structure.     

Uniform hierarchical silica film with perpendicular macroporous channels and accessible ordered mesopores for biomolecule separation

Herein, we demonstrate that silica films with perpendicular macroporous channels and accessible ordered mesopores can be conveniently prepared. The hierarchical macroporous–mesoporous silica films are synthesized by using zinc oxide nanorod array as macroporous template and CTAB surfactant as mesoporous template. In basic surfactant-containing solution, ordered mesoporous silica shells homogeneously grow on the zinc oxide nanorod array. The growth of the mesostructures do not require any chemical modification for the zinc oxide nanorod, which opens a new way for preparing hierarchical silica films with perpendicular mesochannels. The prepared hierarchical macroporous–mesoporous silica films possess a uniform thickness of 2 mm, large perpendicular macropores with a length of 1.8 mm and a width of 80 nm, and accessible ordered mesopores. Separation experiment demonstrates that this macroporous–mesoporous film can effectively separate biomolecules with different sizes.     

多支链烷基苯磺酸钠水溶液的表面性质

用自制的四种高纯度多支链烷基苯磺酸钠,研究了支链结构对其表面性质的影响.结果表明,随支链烷基碳数增加,临界胶束浓度降低,标准吸附自由能DGadӨ更负;但是,饱和吸附量Γmax却随支链烷基碳数增加而减小,且临界胶束浓度时的表面张力γcmc随吸附量减小而降低,表现出与一般表面活性剂不同的变化趋势.从多支链烷基苯磺酸钠的分子结构特点,解释了随支链烷基碳数增加Γmax和γcmc的变化规律,探讨了分子的独占面积(as)对Γmax及γcmc的影响.     

Influence of demulsifiers of different structures on interfacial dilational properties of an oil-water interface containing surface-active fractions from crude oil

The influences of two commercial demulsifiers that have a straight chain and branch chain, respectively, on the dilational viscoelasticity of an oil-water interfacial film containing surface-active fractions from crude oil were investigated. The branch-chain demulsifier AE-121 could efficiently substitute surface-active fractions of different average molecular weights from the oil-water interface, while straight-chain SP-169 could only efficiently substitute those of large average molecular weight. It was apt to form a mix-adsorption layer with surface-active fractions of small average molecular weight. The results showed that the molecular size (or represented by average molecular weights) of the surface-active fractions was an important factor influencing the reciprocity of demulsifiers and surface-active fractions at the oil-water interface. This effect could be well explained by the difference between sizes of surface-active fraction molecules and vacancies between demulsifier molecules at the interface. The results of SDBS also proved this explanation.     

CuAl2O4 powder synthesis by sol-gel method and its photodegradation property under visible light irradiation

Nanocrystalline spinel CuAl₂O₄ powders were prepared by sol-gel method from nitrate Cu(NO₃)₂·3H₂O, Al(NO₃)₃·9H₂O and complex C₆H₈O₇·H₂O. Sintering was carried out at 400, 500, 600, 700, 800°C respectively for 2 h in air. The XRD patterns started to appear CuAl₂O₄ peaks after sintering of 500°C and consist of only CuAl₂O₄ peaks as spinel crystal after sintering of 700°C. The powders were analyzed by TEM and UV-vis diffuse reflectance spectrum to be round, about 10–30 nm in size and Eg=1.77 eV. Photodegradation property of nanocrystalline CuAl₂O₄ powders was investigated by using methyl orange as model pollutant and mercury lamp (λ>400 nm) as energy source. The results indicated that CuAl₂O₄ powders sintered at 700°C had the excellent visible photocatalytic property. Under the irradiation of visible light, methyl orange could be degraded 97% in 120 min.     

直接甲醇燃料电池阳极电催化剂

直接甲醇燃料电池作为未来清洁的动力能源，由于具有下列优点：操作温度低(<100℃)、燃料易储存和运输、能量效率高、污染低和燃料启动快而受到人们广泛的关注。阳极电催化剂是直接甲醇燃料电池最重要的组成部分。本文综述了近三年来直接甲醇燃料电池阳极电催化剂最新的研究进展，主要对催化剂制备方法、新型碳载体材料、催化剂类型作了详细的评述，展望了未来甲醇电催化氧化催化剂的发展，指出了电催化剂面临的问题。     

城市化背景下农用地价格体系的构建与量化--以宜兴市为例

把农地的生态环境价值、社会价值以及生产经济价值一起作为农地非农化中农地的转化价格，讨论了其价格体系的构建方法，对生产经济价格采用收益还原法，社会保障价格采用养老保险法，社会稳定价格采用耕地开垦费法，生态环境价格采用影子价格法来分别进行该价格体系的量化，得到了宜兴市农用地价格体系，进行了土地增值收益的测算，指出目前我国征地补偿价格过低的现象，并初步探讨了土地增值收益在国家、集体和农民之间的分配问题．     

神经网络专家系统在试井解释中的应用

论述了应用专家系统和人工神经网络自动识别试井解释模型的新方法．首先应用人工智能对试井解释模型的压力导数图进行识别，建立了用专家系统构成模块式识别系统；然后应用人工神经网络实现试井解释模型识别；该系统能根据新的试井资料识别试井解释模型；最后，神经网络和专家系统相结合用于试井解释．油田实际试井数据的识别结果说明该方法是一种非常有效的识别方法，对不完全的，有噪声的试井数据也能有效地识别，识别准确率较其它方法都有较大提高     

pH effect of· OH radical induced oxidation of phosphoryl- methionine in aqueous solution

Conclusion The results of pulse radiolytical research on the · OH radical-induced oxidation of NDM in aqueous solution demonstrate that pH value has a great influence on the radiolytical mechanism of NDM. At low pH value, the product is mainly stabilization of the oxidizing sulfur centre in the three-electron-bonded cation radical NDM₂ ·⁺ [S]; with the increase of pH value, NDM₂ ·⁺ [S] gradually decays to become the reducing α-amino radical which was verified by the chemical method and whose yield was also calculated. Compared with Met₂ ·⁺ [S] produced by the · OH radical-induced oxidation in aqueous solution [1], the stability of NDM₂·⁺ [S] increases and the yield of α-amino radical decreases. This suggests that the introduction of phosphoryl group has a coordinating effect on the radioprotection of methionine to biological systems, and provides the essentially theoretical foundation for the thorough clarification of the reversible phosphorylation of proteins.