硫脲和富马酸为主体晶格的四丁基铵包合物的合成及晶体结构

合成了硫脲和富马酸为主体晶格的正四丁基铵阳离子包合物(C4H9)4N ·1/2C4H2O2-4·1/2C4H4O4·3(NH2)2CS, 并通过单晶X射线衍射法对其进行了晶体结构测定. 结果表明: 晶体属三斜晶系, P1(No.2)空间群, a=0.94620(13) nm, b=1.18428(16) nm, c=1.6703(2) nm, α=93.742(2)°, β=91.171(2)°, γ=109.783(2)°, Z=2, V=1.7557(4) nm3, Dc=1.108 g·cm-3, μ(MoKα)=0.071 mm-1, F(000)=636, 对6113个独立衍射点的最终偏离因子R1=0.0910. 包合物中, 独立的硫脲分子间通过氢键连接, 形成沿(001)点阵面无限延伸的二维氢键褶皱网格, 构成类长方形管道的1对管壁, 富马酸分子与富马酸阴离子间以氢键连接形成二聚体,构成管道的另一对管壁, 每个管道内包含了2列规则排列的正四丁基铵阳离子(n-C4H9)4N .     

氧化钛纳米晶溶胶作为共振光散射探针检测L-酪氨酸

以自制粒径约6 nm的氧化钛纳米晶与L-酪氨酸结合后对共振光散射有增敏作用为基础,建立了以TiO2纳米晶溶胶为探针的共振光散射法检测溶液中L-酪氨酸的方法. 考察了pH、超声时间、静置时间、纳米晶浓度和干扰组分对测定的影响. 酪氨酸浓度在0.5～4.0×10-6 g·mL-1 范围呈现较好的线性, 工作曲线的回归方程为ΔIRLS=640.9c+163.4,r=0.993,检出限为1.0×10-7 g·mL-1. 测定了复方氨基酸注射液(18AA)中酪氨酸的含量, 回收率为(99.5～102.0)%,相对     

多规则产品协同设计任务动态排序

针对基于单一特征的任务排序规则的局限性,提出了一种基于复合规则的协同设计任务动态排序方法.在该方法中,建立了协同产品开发中任务完成时间模型、任务排序特征体系.通过仿真方法并在仿真结果基础上,构建了规则权重的多目标函数,求得了各规则的权重.然后用权重对各规则下的排序进行复合和优序处理,确定出优化的设计任务排序.     

废弃混凝土代替天然石灰石煅烧水泥熟料实验

从4个不同地点取得4个以破碎石灰石为粗集料的废弃混凝土样品,破碎、分离,获得以石灰石为主的颗粒,取代天然石灰石作为钙质原料煅烧出4个波特兰水泥熟料样品,并与重庆拉法基水泥厂生产的熟料和市售水泥样品进行对比.研究结果表明:废弃混凝土熟料的4种主要矿物的XRD特征峰明显;游离CaO低于1%;可以用其制备出52.5级硅酸盐水泥.     

相转移法合成哒嗪类糖苷

本文采用相转移法,使乙酰基-α-D-溴代糖1(A-C)与6-(4-甲氧基)苯基-3(2H)-哒嗪酮2以及6-(4-羟基苯基)-4,5-二氢-3(2H)-哒嗪酮5反应合成了3(A,C)及6(A,B)四个乙酰基糖苷化合物.其中3A经氨解脱去保护基又得到一个化合物4A′.其结构被IR、1HNMR和元素分析所证实.     

Atmospheric heterogeneous reaction of acetone: Adsorption and desorption kinetics and mechanisms on SiO2 particles

Acetone plays an important role in photooxidation processes in the atmosphere. Up to date, little is known regarding the heterogeneous fate of acetone. In this study, the adsorption and desorption processes of acetone on SiO2 particles, which are the major constituent of mineral dust in the atmos-phere, have been investigated for the first time under the simulated atmospheric conditions, using in situ transmission Fourier transform infrared spectroscopy. It is found that acetone molecules are adsorbed on the surfaces of SiO2 particles by van der Waals forces and hydrogen bonding forces in a nonreactive and reversible state. The rates of initial adsorption and initial desorption, initial uptake coefficients and adsorption concentrations at equilibrium have been determined at different relative humidity. The presence of water vapor cannot result in the formation of new substances, but can decrease the adsorption ability by consuming or overlapping the isolated OH groups on the surfaces of SiO2 particles. In the desorption process, a considerable amount of acetone molecules will remain on SiO2 particles in dry air, whereas acetone molecules are almost completely desorbed at a high relative humidity. In order to evaluate the role of heterogeneous reactions of acetone and other carbonyl compounds in the atmosphere, a new model fitting the atmospheric conditions is needed.     

Progress and prospect for high temperature single-phased magnetic ferroelectrics

Magnetic ferroelectrics are one of the most important functional materials. The present bottleneck limiting applications of them is lacking of high-temperature single-phased ferromagnetic-ferroelectric multiferroics with strong magnetoelectric coupling effect. Here, those progresses of the mechanism for coexistence of ferroelectric and magnetic order, experimental and theoretical studies on single-phased magnetic ferroelectrics, and the relationship between magnetic structure and crystal symmetry are summarized. With examples of BiFeO3, BiMnO3 and Bi2FeCrO6, the difficulties encountered in this field are analyzed. At last, some prospects to develop high-temperature single-phased ferromagnetic-ferroelectric multiferroics are also presented.     

个体保单在两种分布模型下的平均索赔额

本文在索赔次数服从混合Poisson分布与复合Poisson—Geometric分布的基础上,当个体保单索赔额服从指数分布时,给出了累计索赔额服从的分布及个体保单的平均索赔额表达式．     

铁氧化合物对多孔陶瓷滤料表面改性的研究

通过液相沉积、多次涂层法研究了陶瓷滤料的改性.用均匀试验设计方法优化了改性工艺,并对改性滤料的铁覆盖量、抗酸碱和抗机械耐磨性能、比表面积、表面形貌和铁氧粉末的物相组成进行了表征分析.结果表明,2号样品改性工艺为最佳,其比表面积、铁覆盖量、抗酸碱和抗机械耐磨铁脱落率最大或最少,分别为4.987 m2/g、12.181 2 mg/g、0.016 22%、0.015 09%、0.230 7%,铁涂层的主晶相为α-Fe2O3,为多孔结构.改性滤料的这些特性为增强其除污能力奠定了基础.图5,表1,参8.     

复合型英语人才的培养模式研究

伴随着国际化、市场化进程的加速,我国高等教育改革和发展面临着前所未有的机遇,同时也面临着空前的考验。在这种形势下,针对我国英语教育存在的实际问题,必须加大英语专业复合型人才的培养力度,使学生的综合素质进一步提高,使之适应社会发展的需要。