三个具有抗菌活性的新化合物的分离及结构确证

从标号为F14945的发酵液中分离出三个新化合物:F14945-B1、14945-C、F14945-D1,其化学结构得到确证,经测定这三个化合物都有一定的抗菌活性。     

Equilibrium solubility of sodium 3-sulfobenzoate in binary (sodium chloride + water), (sodium sulfate + water), and (ethanol + water) solvent mixtures at temperatures from (278.15 to 323.15) K

The solubility of sodium 3-sulfobenzoate in binary (sodium chloride + water), (sodium sulfate + water), and (ethanol + water) solvent mixtures was measured at elevated temperatures from (278.15 to 323.15) K by a steady-state method. The results of these experiments were correlated by a modified Apelblat equation. The dissolution enthalpy and entropy of sodium 3-sulfobenzoate in aqueous solutions of different mole fraction were obtained.     

纳米银/二维石墨相氮化碳/还原氧化石墨烯复合材料的制备及其光催化降解抗生素

为优化石墨相氮化碳(g-C₃N₄)光催化剂的结构,改善其对污染物的降解性能,本文以三聚氰胺为前驱体,通过高温煅烧和热氧化剥离制备了二维石墨相氮化碳(2D-C₃N₄),并用光还原法一步合成纳米银/二维石墨相氮化碳/还原氧化石墨烯(Ag/2D-C₃N₄/rGO)复合光催化剂。通过X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、紫外-可见漫反射光谱(UV-Vis DRS)、光致发光光谱(PL)、X射线光电子能谱(XPS)、氮气吸附脱附等温曲线(BET)等对材料进行表征。 以头孢曲松钠为目标污染物,探究pH值、催化剂用量、头孢曲松钠初始浓度等因素对催化剂的吸附、降解性能的影响,并探究降解反应机理。 当pH=6.0,催化剂用量为0.3 g/L,头孢曲松钠初始浓度为10.0 mg/L时,复合材料对头孢曲松钠的降解率可达到89.1%。 催化剂的稳定性较强,具有实际应用价值,可用于处理含头孢类抗生素的废水。     

火花放电原子发射光谱法测定钛及钛合金中主要元素

采用火花放电原子发射光谱法测定了钛及钛合金中碳、铁、铝和钒的含量。通过对钛合金样品的表面处理方式、氩气流量和压力、类型标准化等参数的摸索,确立了一套系统的分析方法。结果表明,4种元素测定的相对标准偏差在0.40%～6.8%,测定结果和化学湿法分析结果相比基本一致,比较适合批量检测。     

A dipping method for radioactivity measurement in water using plastic scintillator

Journal of Radioanalytical and Nuclear Chemistry - A new dipping method was studied for the measurement of radioactive solution using plastic scintillator sheets and pellets (PSs) and a liquid...     

离子色谱法分析保险粉工业回收甲酸钠中的阴离子

利用单柱阴离子交换色谱法测定了保险粉工业回收产品中的甲酸,Cl－,SO,NO,羟乙基硫代硫酸盐,SO和S2O。以1．8mmol／L邻苯二甲酸和1．35mmol／L三羟甲基氨基甲烷的混合溶液作淋洗液,流速为1．0mL／min时,分离效果良好。7种离子的加标回收率在96％～102％之间,检测下限在0．2～5mg／L之间,方法准确、简便。     

一个多因子信用违约互换定价模型

考虑一个违约互换的多因子的简化模型,通过测度的转化并求解一个多变量Riccati常微分方程而得出了这个模型的解析解.此模型是Duffie-Pan-Singleton(2000)模型的特例,但是这个模型存在解析解,而Duffie-Pan-Singleton模型并不存在解析解.模型的解析解对获得直觉的判断和进行模型的计算都非常有帮助,而且模型的解析解对实证检验也是有帮助的.     

Direct measurement of sidewall roughness of polymeric optical waveguides

Sidewall roughness (SWR) of fluorinated polyether waveguides fabricated using reactive ion etching in pure oxygen gas was directly measured using atomic force microscopy (AFM). We confirm that SWR is not the replicate of line edge roughness (LER) of the waveguides. Statistical information such as standard deviation of roughness, autocovariance function (ACF), and autocorrelation length (ACL) have been obtained from AFM measurements. The ACL varies in the similar manner as SWR along the depth of the waveguide, and both are dependent on the etch depth. The depth dependence can be explained by the change in the arrival dynamics of etchant ions in a mechanism involving both shadowing and first-order reemission effects.     

On the direction of the magnetic line and the circulating supercurrent of a vortex in type-II superconductors

The relationship between the direction of the magnetic line and the circulating supercurrent of a vortex in type-II superconductors is discussed. Contrary to the views presented in some articles, we will make it clear that the magnetic line and the circulating supercurrent of a vortex have a “right hand” relationship by considering basic electrodynamics and the lowest energy principle.     

Ultrasonic pre-treatment modifies the pH-dependent molecular interactions between β-lactoglobulin and dietary phenolics: Conformational structures and interfacial properties

There is a need to understand the ultrasound-induced changes in the interactions between proteins and phenolic compounds at different pH. This study systematically explored the role of high-intensity ultrasound pre-treatment on the binding mechanisms of β-lactoglobulin (β-LG) to two common phenolic compounds, i.e., (−)-epigallocatechin-3-gallate (EGCG) and chlorogenic acid (CA) at neutral and acidic pH (pH 7.2 and 2.4). Tryptophan fluorescence revealed that compared to proteins sonicated at 20% and 50% amplitudes, 35%-amplitude ultrasound pre-treatment (ULG-35) strengthened the binding affinities of EGCG/CA to β-LG without altering the main interaction force. After phenolic addition, ULG-35 displayed a similar but a greater extent of protein secondary and tertiary structural changes than the native protein, ascribed to the ultrasound-driven hydrophobic stacking among interacted molecules. The dominant form of β-LG (dimer/monomer) played a crucial role in the conformational and interfacial properties of complexes, which can be explained by the distinct binding sites at different pH as unveiled by molecular docking. Combining pre-ultrasound with EGCG interaction notably increased the foaming and emulsifying properties of β-LG, providing a feasible way for the modification of bovine whey proteins. These results shed light on the understanding of protein–phenolic non-covalent binding under ultrasound and help to develop complex systems with desired functionality and delivery.