外加盐作用形成的正负离子表面活性剂双水相

癸基三乙基溴化铵-癸基磺酸钠（C10NE-C10SO3）等摩尔混合均相体系（即使在表面活性剂总浓度高达0.2 mol•L－1时仍然可形成稳定的均相溶液）在外加盐NaF、Na2SO4和Na3PO4的作用下可自发分离成两个水相（双水相）.研究了该类双水相体系的形成、相行为及其对牛血清蛋白（BSA）的分配，并与普通的正负离子表面活性剂混合双水相体系进行了比较.结果表明，该类双水相体系克服了普通的正负离子表面活性剂混合双水相体系的一些不足，具有一些独特的优点.该类双水相体系的相行为可以通过外加盐进行调控,通过外加盐的种类来调控和优化BSA的分配行为.图1表2参8     

单核锇配合物的合成、晶体结构及其与DNA的作用

使用溶剂热合成法,以p-bitmb配体(1,4-二(1-咪唑基-亚甲基)-2,3,5,6-四甲基苯)与[(η6-cymene)Os(μ-Cl)Cl]2或[(η6-bip)Os(μ-Cl)Cl]2为原料,合成了2种单核芳基锇配合物,并利用核磁、质谱、元素分析和X射线单晶衍射等手段对配合物进行了表征。配合物1属于单斜晶系,P21/c空间群,为一个单核锇的结构。中心锇原子与2个配体p-bitmb上的氮原子以及氯原子进行配位,2个配体的另一个咪唑基团通过一个亚甲基碳原子进行连接形成咪唑嗡离子,形成一个类似"碗"状的结构。一个氯离子通过氢键装载在结构的空腔内。利用核磁共振氢谱研究了结构中亚甲基的来源,并研究了配合物在缓冲溶液中的稳定性。用紫外吸收光谱、圆二色谱以及粘度法研究了配合物与DNA的相互作用,结果表明,配合物中的亚甲基来自于溶剂二氯甲烷。配合物以嵌入的方式与CT-DNA相互作用,结合常数分别为3.222×10~4 L·mol-1 (1)和1.53×10~4 L·mol-1 (2),同时配合物会减弱DNA的碱基堆积作用并可以使DNA发生解旋。     

凸四边形的边长与直径的不等式

设单位直径的平面凸四边形的边长是ａ,ｂ,ｃ,ｄ,Ｔａｍｖａｋｉｓ与Ｇｏｌｉｋｏｖ在１９８７年给出了ａ＋ｂ＋ｃ＋ｄ≤２＋√６－√２,本文作者证明了１／ａ＋１／ｂ＋１／ｃ＋１／ｄ≥４√２,ａｂｃｄ≤２－√３,ａ＾ｋ＋ｂ＾ｋ＋ｃ＾ｋ＋ｄ＾ｋ≤３（ｋ≥２）,这些界都是最佳的。     

Synthesis of diblock copolymers containing poly(N‐vinylcarbazole) by reversible addition‐fragmentation chain transfer polymerization

The reversible addition‐fragmentation chain transfer (RAFT) polymerization of N‐vinylcarbazole (NVK) mediated by macromolecular xanthates was used to prepare three types of block copolymers containing poly(N‐vinylcarbazole) (PVK). Using a poly(ethylene glycol) monomethyl ether based xanthate ( PEG‐X ), the RAFT polymerization of NVK proceeded in a controlled way to afford a series of PEG‐b‐PVK with different PVK chain lengths. Successive RAFT polymerization of NVK and vinyl acetate (VAc) with a small molecule xanthate ( X1 ) as the chain transfer agent was tested to prepare PVK‐b‐PVAc. Though both monomers can be homopolymerized in a controlled manner with this xanthate, only by polymerizing NVK first could give well‐defined block copolymers. The xanthate groups in the end of PVK could be removed by radical‐induced reduction using tributylstannane, and PVK‐b‐PVA was obtained by further hydrolysis of PVK‐b‐PVAc under basic conditions. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

运动黏度在FLC薄膜-白油固液复合润滑体系中的作用

利用直流等离子体沉积技术制备了含氢类富勒烯碳膜(FLC),在工业级白油润滑条件下考察了FLC薄膜润湿性、摩擦学特性和白油运动黏度对整个固液复合润滑体系的影响。研究结果表明:在5~150 mm~2/s的考察范围内,白油的运动黏度越小,其对FLC薄膜的润湿性越好;随着运动黏度的增大,白油分子量增加且分子链变长,在薄膜表面油膜吸附增强,油膜厚度增加,FLC薄膜摩擦系数逐渐减小,于32 mm~2/s时达到最小值(0.114),随着黏度进一步增大,过高的运动黏度增加了黏性阻力和摩擦阻力,FLC薄膜摩擦系数反而上升;同时,FLC薄膜的磨损率随黏度增大而减小,当黏度超过26 mm~2/s之后,变化幅度趋缓。     

聚龙一号装置的强电磁干扰对PDV的影响研究

光子多普勒测速系统(PDV)常采用全光纤模式, 操作方便, 已成为材料超高压动态实验获取动力学特性的重要诊断技术。测速范围和精度与光电传感器和数据采集仪器有关, 激光到达靶面后返回光电转换器, 速度由多普勒引起的频率变化直接解读。聚龙一号装置是开展材料动态实验的重要平台, 放电电流峰值5~8MA, 0~100%上升时间300~750ns。在装置放电过程中, 靶室和大厅中的强电磁干扰可以达到10~300MHz, 当干扰耦合进返回光信号后, 导致速度剖面解读困难。采用聚四氟乙烯绝缘膜和导电铝膜包覆测速探针很好地抑制了强电磁干扰信号对光信号的干扰, 大大提高了速度测量数据的有效性。     

基于ASME应变限制准则的小冲杆试验等效断裂应变

为更清楚地了解阳江35kV服役导线的运行状态,从分析导线断线原因出发,通过对老旧导线的单丝断裂强度、弹性模量、应力应变曲线、拉断力、抗拉强度等综合指标的测试与分析,研究服役导线的力学性能,由试验结果得出：35kV老旧导线钢芯的直径变化对于架空导线的外径变化有直接的影响,老旧导线的铝线直径变化较小,其外径增大1.67％~4.24％;钢单线的拉断应力仍能达到标准中规定值的106%,且伸长率也满足要求;部分铝线的抗拉强度低于95%;绞线拉断力仍能达到95%的计算拉断力。但是相同规格下的老旧导线的抗拉强度比新导线的抗拉强度低2%~18%。结果表明：阳江地区服役三十年以上的老旧导线在力学性能上仍能继续承载。     

Experimental and Theoretical Studies on DNA‐Binding and Spectral Properties of ‘Light Switch’ Complexes [Ru(L)2(ppn)]2+ (L=2,2′‐Bipyridine and 1,10‐Phenanthroline; ppn=Pteridino[6,7‐f] [1,10]phenanthroline‐11,13‐diamine)

The ligand pteridino[6,7‐f] [1,10]phenanthroline‐11,13‐diamine (ppn) and its Ru^II complexes [Ru(bpy)₂(ppn)]²⁺ ( 1 ; bpy=2,2′‐bipyridine) and [Ru(phen)₂(ppn)]²⁺ ( 2 ; phen=1,10‐phenanthroline) were synthesized and characterized by elemental analysis, electrospray MS, ¹H‐NMR, and cyclic voltammetry. The DNA‐binding behaviors of 1 and 2 were studied by spectroscopic and viscosity measurements. The results indicate that both complexes strongly bind to calf‐thymus DNA in an intercalative mode, with DNA‐binding constants K_b of (1.7±0.4)?10⁶ M ^?1 and (2.6±0.2)?10⁶ M ^?1, respectively. The complexes 1 and 2 exhibit excellent DNA‐‘light switch’ performances, i.e., they do not (or extremely weakly) show luminescence in aqueous solution at room temperature but are strongly luminescent in the presence of DNA. In particular, the experimental results suggest that the ancillary ligands bpy and phen not only have a significant effect on the DNA‐binding affinities of 1 and 2 but also have a certain effect on their spectral properties. [Ru(phen)₂(ppn)]²⁺( 2 ) might be developed into a very prospective DNA‐‘light switch’ complex. To explain the DNA‐binding and spectral properties of 1 and 2 , theoretical calculations were also carried out applying the DFT/TDDFT method.     

Simultaneous determination of inorganic arsenic,antimony, selenium and tellurium by ICP-MS in environmental waters using SPE preconcentration on modified silica

This paper deals with a simplified multi-element profiling of inorganic arsenic, antimony, selenium and tellurium in the form of ⁷⁵As, ⁸²Se, ¹²¹Sb and ¹²⁵Te by ICP-MS for amounts less than 10?µg?L^?1. Internal standards such as ⁷²Ge and ²⁰⁹Bi were successfully used for the suppression of both influence of macro elements Na⁺, K⁺, Ca²⁺, Mg²⁺ or Al³⁺, and interference of limited concentrations of heavy metal ions. Modified silica sorbents Separon? SGX C18, C8, CN, NH₂, RPS and Phenyl were tested for the preconcentration of As, Sb, Se and Te (0.25–5?µg?L^?1) in the form of ion associates with cationic surfactants from 50–250?mL sample volume. 1-etoxycarbonyl-pentadecyltrimethylammonium bromide (Septonex®, 0.005?mol?L^?1) was suitable for this purpose in the presence of 4-(2-pyridylazo) resorcinol, 2-pyrrolidinecarbodithioate and 8-hydroxyquinoline-5-sulphonic acid. The quantitative retention occurred at pH 7?±?0.2 and the mixture of acetone with ethanol in ratio 1?:?1 in the presence of 0.1?mol?L^?1 HCl was used for the quantitative elution. Organic solvents and the excess of acid were removed by evaporation prior to the determination by ICP-MS. The determination of the above trace metalloids in various kinds of water with enrichment factor till 50 times on silica Separon? SGX C18 and the above reagents were compared with the standard addition method.     

A microchip-based proteolytic digestion system driven by electroosmotic pumping

Microchip-based proteomic analysis requires proteolytic digestion of proteins in microdevices. Enzyme reactors in microdevices, fabricated in glass, silicon, and PDMS substrates, have recently been demonstrated for model protein digestions. The common approach used for these enzyme reactors is employment of a syringe pump(s) to generate hydrodynamic flow, driving the proteins through the reactors. Here we present a novel approach, using electroosmotic flow (EOF) to electrokinetically pump proteins through a proteolytic system. The existence of EOF in the proteolytic system packed with immobilized trypsin gel beads was proven by imaging the movement of a neutral fluorescent marker. Digestions of proteins were subsequently carried out for 12 min, and the tryptic peptides were analyzed independently using capillary electrophoresis (CE) and MALDI-TOF mass spectrometry (MS). The results from CE analysis of the tryptic peptides from the EOF-driven proteolytic system and a conventional water bath digestion were comparable. MALDI-TOF MS was used to identify the parent protein and the tryptic peptides using MS-Fit database searching. The potential utility of the EOF-driven proteolytic system was demonstrated by direct electro-elution of proteins from an acrylamide gel into the proteolytic system, with elution and tryptic digestion achieved in a single step. The EOF-driven proteolytic system, thus, provides a simple way to integrate protein digestion into an electrophoretic micro total analysis system for protein analysis and characterization.