烷烃的蒸发热与其分子结构关系的研究

本文提出了烷烃在标准状态下蒸发热的简易计算式△H_(v,298)~0=0.43438M+sum from i to n(C_(lj)~-+mδ式中M为分子量,C_(lj)和δ为结构常数,n和m分别为分子中碳数和季碳、叔碳相邻接的个数。按此式计算了150多个烷烃在标准状态下的蒸发热。计算值与实验值的平均误差小于1％。     

White light emission from Dy3+-doped LiLuF4 single crystal grown by Bridgman method

Lithium lutetium fluoride （LiLuF4） single crystals doped with different Dy3＋ ion concentrations were grown by Bridgman method. The Judd-Ofelt （J-O） strength parameters （Ω2, Ω4, Ω6） of Dy3＋ in LiLuF4 crystal are calculated according to the measured absorption spectra and the J-O theory, by which the asymmetry of the Dy3＋：LiLuF4 single crystal and the possibility of attaining stimulated emission from 4F9/2 level are analyzed. The capability of the Dy3＋：LiLuF4 crystal in generating white light by simultaneous blue and yellow emissions under excitation with ultra- violet light is produced. The effects of excitation wavelength and doping concentration on chromaticity coordinates and photoluminescence intensity are also investigated. Favorable CIE coordinates, x=0.319 3 and y=0.349 3, can be obtained for Dy3＋ ion in 2.701% molar doping concentration under excitation of 350 nm.     

丙烯与醋酸直接催化合成醋酸异丙酯

丙烯与醋酸在 NSE 0 1催化剂上直接加合成醋酸异丙酯。研究了丙烯与醋酸的配比 ,反应温度 ,接触时间等反应条件。较佳条件是 :反应温度 4 0 3 ,丙烯与醋酸的的流速分别为 1 2 L/h和 7m L/h,催化剂用量 1 0m L,丙烯与醋酸摩尔比为 3～ 4∶ 1。在较佳条件下醋酸异丙酯时空产率达 30 0～ 4 0 0 g/( h· L)。催化剂连续运行 50 0 h活性未见下降。     

烯烃,脂环烃和芳烃的蒸发热与分子结构关系的研究

标准状态下烯烃、环烷烃和芳烃蒸发热的计算式可表示为：△Ｈ＾０ｖ，２９８＝０．４３４３８Ｍ＋ΣＣｉｊ＋ΣｍＧｘｊ＋Σ１δｙ按式计算了２６０多个烷烃、烯烃、环烷烃和芳烃分子的蒸发热，计算值与实验值的平均误差小于１．１％。     

丙烯与醋酸直接合成醋酸异丙酯的新途径

丙烯与醋酸直接合成醋酸异丙酯的新途径章哲彦，王冬杰，任元龙，邵颖（宁波师范学院化学系，３１５０２０）醋酸酯是一类重要的化工原料和溶剂，传统的制备方法是由相应的醇和醋酸在硫酸催化下合成。由于醇来自粮食或由相应的烯烃水合而得，因此该法成本高。本文则介绍由...     

Tunable emission,concentration quenching and crystallographic sites of Eu^2＋ in Sr3Y（PO4）3

A series of Sr3Y（PO4）3：Eu^2＋ samples are synthesized by the high temperature solid-state method. Sr3Y（PO4）3：Eu^2＋shows an asymmetrical emission band under excitation of 350 nm. The emission peaks at 426 nm and 497 nm are assigned to the nine-coordination Eu^2＋ and six-coordination Eu^2＋, respectively. The effects of Eu^2＋ doping content on the emission intensity and color are observed, and the concentration quenching effect is also observed. For two different Eu^2＋ luminescence centers, the quenching mechanisms are dipole-dipole interaction and quadrupole-quadrupole interaction, respectively. And the critical distance of energy transfer is calculated by concentration quenching and turns out to be about 3.67 nm. The results above show that the asymmetrical emission band of Sr3Y（PO4）3：Eu^2＋ comes from two different Eu2＋ luminescence centers in the lattice.     

零价铁去除U(Ⅵ)的作用机理及其影响因素

在核废料处理中,如何将毒性大、易迁移的放射性核素U(Ⅵ)转化为毒性小、难迁移的U(Ⅳ)是非常关键的处理步骤。零价铁还原技术由于其价格廉价、环境友好、工艺简单等优点,在放射性核素U(Ⅵ)的还原处理方面也显示了较好的应用前景。本文详细地论述了零价铁去除U(Ⅵ)的3种界面化学作用机理：还原沉淀机理、吸附机理、共沉淀机理;还就各种水化学因素：氧化还原条件、介质pH、共存离子、天然有机质及微生物等对反应作用机理的影响进行了较为深入的讨论;并对如何有效、深入开展零价铁去除U(Ⅵ)的今后研究方向进行了展望。     

甲烷芳构化反应催化剂Ｍｏ-Ｍ／ＨＺＳＭ-５表面性质的研究

对甲烷芳构化催化剂Ｍｏ-Ｍ／ＨＺＳＭ-５进行了异丙醇分解、ＮＨ３-ＴＰＤ-ＭＳ、积炭量测定表征,其结果均与芳构化性能有关。芳烃收率高,稳定性好,积炭量较少,而且具有相当量的酸量和一定量强酸量及较强的脱氢中心。     

掺杂卟啉铜的TiO2/SiO2有机-无机复合材料制备及其非线性折射率

以正硅酸乙酯与钛酸丁酯为前驱体,用溶胶-凝胶法将水溶性的5,10,15,20-四(4-磺酸苯基)卟啉铜(tetra(4-sulfonatophenyl)porphine,TPPS)(Cu(Ⅱ)-TPPS)掺杂到TiO2/SiO2固体介质中,制备了Cu(Ⅱ)-TPPS掺杂TiO2/SiO2有机-无机复合材料.通过分析样品...     

铁系催化剂的鉴定与分析

应用因素分析法于铁系催化剂体系的紫外光谱,对六种样品进行了成份的鉴定。其二种成份为乙酰丙酮和α,α’—联吡啶,并测定了它们的组成。实验值与予计值颇为一致。