负载型Pd-Cu催化剂的制备及富氢气氛下CO优先氧化性能

分别以Al₂O₃, SiO₂和C₃N₄为载体, 通过简单浸渍法制备了3种负载型Pd-Cu催化剂(PC-Al₂O₃, PC-SiO₂, PC-C₃N₄), 考察了其在室温下富氢气氛中CO优先氧化反应性能. 采用X射线衍射(XRD)、 傅里叶变换红外光谱(FTIR)、 氮气物理吸附仪(N₂-physisorption)、 氢气程序升温还原(H₂-TPR)、 二氧化碳程序升温脱附(CO₂-TPD)、 X射线光电子能谱(XPS)和原位漫反射傅里叶变换红外光谱(In situ DRIFTS)等手段对其进行了表征. 结果表明, 与PC-SiO₂和PC-C₃N₄相比, PC-Al₂O₃具有更高的CO优先氧化性能. 这是由于PC-Al₂O₃上形成了大量与Pd物种具有强相互作用的Cu₂Cl(OH)₃物种; 而PC-SiO₂中仅有少量的Cu₂Cl(OH)₃, 且与Pd物种相互作用较弱; PC-C₃N₄中Cu物种则更易与C₃N₄基质配位, 由此削弱了Pd, Cu之间的相互作用. 在反应气氛下PC-Al₂O₃表面还易形成具有更强CO活化能力的Pd⁺物种, 通过与大量Cu⁺物种紧密相互作用, 在一定程度上抑制Pd⁺被过度还原为Pd⁰, 从而维持了其催化活性. 与SiO₂和C₃N₄相比, Al₂O₃更适合负载Pd-Cu用于富氢气氛下CO优先氧化反应.     

New approximate formula for the generalized temperature integral

A new procedure to approximate the generalized temperature integral $ \int_{0}^{T} {T^{m} {\text{e}}^{ - E/RT} } {\text{d}}T, $ which frequently occurs in non-isothermal thermal analysis, has been developed. The approximate formula has been proposed for calculation of the integral by using the procedure. New equation for the evaluation of non-isothermal kinetic parameters has been obtained, which can be put in the form: $$ \ln \left[ {{\frac{g(\alpha )}{{T^{(m + 2)0.94733} }}}} \right] = \left[ {\ln {\frac{{A_{0} E}}{\beta R}} - (m + 2)0.18887 - (m + 2)0.94733\ln {\frac{E}{R}}} \right] - (1.00145 + 0.00069m){\frac{E}{RT}} $$ The validity of the new approximation has been tested with the true value of the integral from numerical calculation. Compared with several published approximation, the new one is simple in calculation and retains high accuracy, which indicates it is a good approximation for the evaluation of kinetic parameters from non-isothermal kinetic analysis.     

Modification of unsaturated polyester resins (UP) and reinforced UP resins via plasma treatment

Unsaturated polyester resins (UP) and reinforced composite unsaturated polyester resins (RCP) were made superhydrophobic by plasma assisted methods. Both CF₄-plasma-enhanced chemical vapor deposition (CF₄-PECVD) and alternative method were tested. The surfaces were characterized by water contact angle (CA) measurements and scanning electron microscopy (SEM). Water contact angle results indicated that CF₄-PECVD can significantly improve the wettability of UP surfaces, but suffer from difficulties for RCP surfaces. Alternatively, O₂ plasma followed by self-assembly of octadecyltrichlorosilane (OTS) self-assembled monolayer (SAM) was tested. It was shown that regardless of the filler percentage, O₂ plasma followed by self-assembly of OTS monolayer formation all led to superhydrophobic surfaces. The results provided a means to improve the wettability of reinforced UP resins (RCP).     

红外光谱法研究镍顺丁橡胶分级样品及凝胶的微结构

顺丁橡胶的链结构与其溶液性质和物理性能有密切关系,凝胶的存在往往影响加工和使用性能。付里叶变换红外光谱技术的发展使我们有可能考察顺丁分子链微结构与分子量的关系,研究凝胶与线性分子链结构的差别。     

黄土边坡剥落病害的发育特征及其发育程度评价

黄土边坡剥落病害影响黄土边坡的坡面稳定及环保美观。以黄延高速公路黄土路堑边坡剥落病害为背景,采用现场调查结合理论分析的方法,研究了黄土边坡剥落病害的发育特征; 将发育特征与可拓工程方法相结合,实现了黄土边坡剥落病害发育程度的评价。研究结果表明:(1)黄土中节理裂隙分布密度大于6条 ·m^-1 时,极易发生剥落,小于2条 ·m^-1 时,基本不发生剥落。黏粒含量大于15%时,剥落病害越易发生,小于5%时,不易发生剥落。黄土边坡开挖量越大、剥落产生的厚度越大。黄土边坡坡体节理裂隙促使剥落病害的发生。当黄土边坡单级坡高大于10m、坡度大于60°时,容易出现重力型剥落病害; 而单极坡高小于4m、坡度小于50°时,边坡坡面很少出现剥落病害。(2)针对影响黄土边坡剥落病害发育因素的复杂性和模糊性,重视实践中的经验,将可拓工程方法与黄土边坡剥落发育程度评价相结合,提出了黄土边坡剥落发育程度的物元关联函数及物元关联度的计算方法。建立了适合可拓学理论的黄土边坡剥落发育程度的分类标准,实现了定性与定量评价结合。     

Preparation, characterization and photocatalytic activity of metalloporphyrins-modified TiO2 composites

Three new Cu(II), Zn(II), Co(II) 5,15-di (4-hydroxyphenyl)-10, 20-diphenyl-porphyrin (CuDHPP, ZnDHPP, CoDHPP) and the corresponding metalloporphyrins–TiO₂ photocatalysts CuDHPP–TiO₂, ZnDHPP–TiO₂, CoDHPP–TiO₂ were synthesized and characterized by SEM, XRD, FT-IR, and DRS. The results revealed that the metalloporphyrins impregnated onto the surface of TiO₂ did not change the phase composition and particle sizes of TiO₂ samples, but increased the photocatalytic efficiency. In addition, photoluminescence study showed that the three photocatalysts could successfully increase the separation efficiency of the photoinduced electron and hole. The photodegrading 4-NP experiments indicated that the three photocatalysts greatly enhanced the photocatalytic activity of bare TiO₂, and the photocatalytic activity of CuDHPP–TiO₂ was the highest. Moreover, the possible mechanism for the photodegradation of 4-NP was also proposed.     

利用猫式自泵浦位相共轭镜的光学联想存储器

报道了以快速响应（１５０ｍｓ），成像质量高（分辨率＞５０ｐｌ／ｍｍ）的１６°切掺铜钾钠铌酸锶钡（Ｃｕ：ＫＮＳＢＮ）晶体猫式自泵浦位相共轭境作为取阈反馈器件，以低吸收薄晶体Ｃｅ：Ｆｅ：ＬｉＮｂＯ３作为存储介质的光学全息联想存储器，利用２５％原信息寻址，可得出完整的联想输出．     

应用诱导互泵浦位相共轭镜的实时图像处理

利用自泵浦诱导的互泵浦位相共轭镜，在１６°切掺铜钾钠铌酸锶钡晶体中，分别对信号图像的完整输出和边缘增强输出实现了两幅图像的实时相加和相减处理。位相共轭输出的成像分辨率高达５０ｐｌ／ｍｍ。     

Synthetic Studies in Phytochrome Chemistry

An account is given of the author's several approaches to the synthesis of the parent chromophore of phytochrome (1), a protein-bound linear tetrapyrrole derivative that controls photomorphogenesis in higher plants. These studies culminated in enantioselective syntheses of both 2R- and 2S-phytochromobilin (4), as well as several (13)C-labeled derivatives designed to probe the site of Z,E-isomerization during photoexcitation. When reacted in vitro, synthetic 2R-4 and recombinant-derived phytochrome apoprotein N-C produced a protein-bound chromophore with identical difference spectra to naturally occurring 1.