Study of surfactant-polymer system containing a novel ternary sulfonated polyacrylamide on the oil-water interface properties

A novel ternary sulfonated polyacrylamide was synthesized using 2,2′-azobis[2- methylpropionamidine] dihydrochloride and redox initiation system as initiator, respectively. The competitive adsorption of the ternary sulfonated polyacrylamide (TSPAM) and sodium dodecyl benzene sulfonate (SDBS) on the oil-water interface was investigated by equilibrium interfacial tension, interfacial viscoelasticity, zeta potendial and interfacial film strength. The SDBS molecules in the surfactant-polymer (SP) system preferentially adsorb on the oil-water interface due to the amphiphilic structure of the SDBS molecules. Electrostatic force between the charged groups of the polyacrylamide and the head groups of surfactant adsorbed on the interface in the SP system leads to the formation of the complex interface film, which is helpful to enhance the stability of the oil-water interface. The ternary sulfonated polyacrylamide (TSPAM) has a similar influence on the other interface properties with SDBS except the interfacial tension. The interfacial tension decreases and then increases with increasing of the TSPAM concentration due to the competitive adsorption of the TSPAM molecules and the SDBS molecules on the oil-water interface. Moreover, TSPAM has the more influence on the stability of oil-water interface than partially hydrolyzed polyacrylamide (HPAM) in the SP system, and the addition of TSPAM is better to improve the stability of emulsion in the SP flooding.     

碳硅二炔结构及性质分子动力学模拟研究

采用基于量子力学的半经验哈密顿量的计算方法,即SCED-LCAO方法,模拟研究了碳硅二炔的稳定性结构、成键特点、电子结构等性质. 得出其最稳定的结构是单层平面结构,晶格常数为12.251 Å. 它通过 含有两个Si-C三键的链连接六元环构成. 这种平面结构在很大高温范围内都可以保持其稳定特性,直到1520 K时,该基本结构才被破坏,且结构中出现四元环. 体系温度低于1520 K时,均可通过降温,恢复其零温时的结构. 研究还发现这种共轭结构中Si,C 原子间存在稳定的sp杂化形式,对分布函数得出其键长为1.58 Å左右. 高温时sp杂化逐渐转变成其他杂化形式. 计算结果表明,在零温下,该电中性系统中存在离域π键,使得系统中的Si-C键长呈现平均化趋势. 研究表明,碳硅二炔的能隙为1.416 eV,LUMO,HOMO能级分别是0.386 eV和–1.03 eV表明了其n型半导体特性. 关键词： 碳硅二炔 分子动力学模拟 sp杂化 稳定性     

苯甲酸氯代衍生物稀土配合物的荧光表征

分别以典型的芳香羧酸苯甲酸及其一氯代衍生物（邻、间、对三种）为第一配体,以邻菲罗啉(phen)或2,2′ 联吡啶((bipy)为第二配体,合成了一系列Tb(III)、Eu(III)的配合物.通过红外光谱、紫外可见光谱、荧光光谱等方法探讨了不同位置的取代基或不同的第二配体对配合物荧光性质的影响.结果显示,邻菲罗啉能够增强Eu(III)芳香羧酸配合物的荧光强度而减弱Tb(III)羧酸配合物的荧光强度;2,2′ 联吡啶则显示相反的结果.     

两种藻类对水体氮、磷去除效果

借助人工装置和露天水池,通过分析实验水体中氮、磷元素浓度的变化,研究了实验室条件下一种绿球藻(Chlorococcumsp.)和露天小型生态系统中寡枝刚毛藻(Cladophora oligoclonaKütz).对污水中氮磷营养的去除效果.结果显示:绿球藻在高浓度氮和磷的污水中生长良好并维持较高的氮磷去除率,在6天处理期间,人工污水中总溶解性氮、硝酸盐氮、氨氮、总溶解性磷的去除率分别达到46.2%,37.8%,98.4%和79.3%;在对天然湖泊水的处理中,绿球藻对总溶解性磷的去除率在第5天为79.2%.室外条件下,该刚毛藻通过吸收水体中的氮、磷营养维持自身正常生长代谢,从而降低水体的电导率和改善水质.根据本次研究,结果两种被试藻类均可作为污水处理用藻类,其中Chlorococcumsp.适合用于静态水体的修复与改善,Cladophora oligoclona适合于流动水体的减负与治理.     

Effect of branched alkyl chains attached at sp3 silicon of donor–acceptor copolymers on their morphology and photovoltaic properties

We study the degree of π?π interactions in two copolymers composed of 2‐octylbenzotriazole and dialkyldithienosiloles with linear hexyl (P1) and branched 2‐ethylhexyl groups (P2). Although the branched ethyl group can be positioned above the π‐plane of dithienosilole to bring disadvantage to stack among the polymers, the solid‐state absorption spectra of the polymers reveal that P2 possesses stronger interchain interactions than P1. We also evaluate the photovoltaic properties of each polymer with [6,6]‐phenyl‐C₇₁‐butyric acid methyl ester. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

硫酸铵提高裂殖壶菌不饱和脂肪酸积累的代谢组学研究

采用基于气相色谱-质谱(GC-MS)联用技术的代谢组学方法,通过分析裂殖壶菌胞内代谢物的变化,研究(NH4)2SO4提高裂殖壶菌不饱和脂肪酸积累的作用机制.利用GC-MS技术对添加0,1.5,2.5和3.5g/L (NH4)2SO4的发酵样品进行分析,结合K-Means算法对数据进行聚类分析,得到胞内代谢物的热图.主成分分析(PCA)和偏最小二乘判别分析(OPLS-DA)得分图可将不同添加条件下裂殖壶菌胞内物质明显区分.运用PLS-DA载荷图及模型的变量重要性因子(VIP)值,发现了7种代谢物可作为区别4种不同条件下的生物标志物.经NIST和Wiley谱库检索,它们分别为葡萄糖、肌醇、甘露醇、果糖、磷酸、乙醇胺、乙胺.代谢途径分析结果表明,(NH4)2SO4是通过弱化糖酵解途径和乙酸合成支路,提高苹果酸酶的活力,强化氨基酸代谢和NADPH的积累,从而提高不饱和脂肪酸积累.     

C−C Coupling of Benzyl Fluorides Catalyzed by an Electrophilic Phosphonium Cation

The activation and cleavage of benzyl fluorides by the electrophilic organofluorophosphonium catalyst, [(C₆F₅)₃PF][B(C₆F₅)₄], is reported and used for the preparation of 1,1‐diarylalkanes (37 examples) and substituted aryl homoallylic alkenes (14 examples). This procedure involves mild conditions, avoids harmful waste, and is compatible with a range of substituted arenes and allylic silanes.     

New cyclic tetrapeptide from the coral-derived endophytic bacteria Brevibacterium sp. L-4 collected from the South China Sea

One new cyclic tetrapeptide cyclic-(Tyr-Ala-Leu-Ser) (1) along with four natural compounds firstly obtained 3H-imidazole-4-carboxylic acid (2), 2-methyl-3H-imidazole-4-carboxylic acid (3), 3-ethylidene-6-isopropyl-piperazine-2,5-dione (4), and 3-isobutylidene-6-methyl piperazine-2,5-dione (5) have been isolated from the coral derived endophytic bacteria Brevibacterium sp. L-4 collected from the South China Sea. Their structures were elucidated through spectroscopic techniques including NMR (1D and 2D), MS, and EA, and their relative configurations were also assigned by NMR analysis.     

New cytotoxic constituents from the Red Sea soft coral Nephthea sp.

Nephthea are soft coral species rich in sesquiterpenoids and steroids. An organic extract of Nephthea sp. resulted in the isolation of a new steroid (1), as well as several previously reported metabolites (2–9). Structures were elucidated by employing NMR and HR-EI-MS analyses. The total extract, fractions and purified compounds exhibited differential cytotoxicity against the breast cancer MCF-7 cell line.     

PdII‐Catalyzed Intermolecular Amination of Unactivated C(sp3)H Bonds

Pd^II‐catalyzed intermolecular amination of unactivated C(sp³)?H bonds has been successfully developed for the first time. This method provides a new way to achieve the challenging intermolecular amination of unactivated C(sp³)?H bonds, producing a variety of unnatural β²‐amino carboxylic acid analogues. This C(sp³)?H amination protocol is demonstrated with a broad substrate scope, good functional‐group tolerance, and chemoselectivity. It is operated without use of phosphine ligand or external oxidant.