2，3—二氨基吩嗪的薄层光谱电化学研究

研究了2，3—二氨基吩嗪(DAP)在金圆盘电极、金超微电极上的循环伏安行为 和在金网栅电极上的薄层循环伏安行为．在pH2．0的B—R缓冲溶液中的2，3—二氨 基吩嗪在金圆盘电极上为准可逆氧还过程；以超微电极法求得了2，3—二氨基吩嗪 在pH2．0的B—R缓冲溶液中的扩散系数，由耗竭性库仑电解和循环伏安法求得其电 极反应电子转移数和H+反应级数均为2，实验说明参与电极反应的H+也为2，并用循 环伏安法求得其标准电极反应速率常数．采用紫外—可见薄层光谱电化学方法测得 2，3—二氨基吩嗪的克式量电位和电子转移数，与电化学实验结果一致；双电位阶 跃—计时吸收紫外—可见薄层光谱电化学实验说明，2，3—二氨基吩嗪电还原无随 后化学反应，其在电极上经历了H+eH+e的两步一电子过程，生成产物2，3—二氨基 -5，10-二氢吩嗪．     

原子探针的发展及其对金属内界面的研究

简要介绍了原子探针，特别是三维原子探针（３ＤＡＰ）的最新发展及其特点３ＤＡＰ在探测到单个原子位置的同时能临别其种类，因而几乎能以原子分和显示出材料中大部分原子在实空间中的三维分布，文章例说明了常规ＡＰ和３ＤＡＰ在研究金属内界面中的应用。     

A novel liquid chromatographic method with fluorescence detection for quantitation of tadalafil and dapoxetine hydrochloride in pharmaceutical dosage form and human plasma北大核心CSCD

Tadalafil( TAD)and dapoxetine HCl( DAP)are recently co-formulated and both show native fluo-rescence. Therefore,a novel,accurate,specific and sensitive reversed-phase high performance liquid chroma-tographic method with fluorescence detection was developed and validated for their separation and quantitation in dosage form and human plasma using avanafil as an internal standard( IS). Separation was achieved using isocratic elution within 7. 0 min on C18 column and acetonitrile-0. 15% triethylamine( 40∶60,v/v;pH 4)as a mobile phase. The flow rate was 1. 0 mL/min and the detection was time-programmed at 330,410 and 370 nm for TAD,DAP and IS,respectively,after excitation at 236 nm. The linear ranges from 0. 01 to 30. 00 μg/mL for each drug with the limits of detection of 4. 20 and 7. 20 ng/mL for TAD and DAP,respectively. The method was validated in accordance to the International Conference on Harmonization( ICH)guidelines and was successful-ly applied to spiked human plasma with mean recoveries of 98. 17% and 98. 83% for TAD and DAP respectively.     

Reduction in etching time for fission tracks in diallyl phthalate resin

Diallyl phthalate (DAP) resin plates were irradiated with fission fragments, and then etched in a conventional aqueous solution of KOH or a PEW solution containing ethanol, water and KOH. Etched tracks were observed and counted by using an optical microscope. The PEW solution made the fission tracks etch-pits clearer in an incomparably shorter etching time. The large and round etch-pits developed on a smooth surface were convenient for optical automatic counting. These etching characteristics of DAP in a PEW solution are suitable for quantitative analysis of fissionable materials and neutron dosimetry.     

Separation of phthalates by cyclodextrin modified micellar electrokinetic chromatography: Quantitation in perfumes

A new CE method has been developed for the simultaneous separation of a group of parent phthalates. Due to the neutral character of these compounds, the addition of several bile salts as surfactants (sodium cholate (SC), sodium deoxycholate (SDC), sodium taurodeoxycholate (STDC), sodium taurocholate (STC)) to the separation buffer was explored showing the high potential of SDC as pseudostationary phase. However, the resolution of all the phthalates was not achieved when employing only this bile salt as additive, being necessary the addition of neutral cyclodextrins (CD) and organic modifiers to the separation media. The optimized cyclodextrin modified micellar electrokinetic chromatography (CD-MEKC) method consisted of the employ of a background electrolyte (BGE) containing 25 mM β-CD-100 mM SDC in a 100 mM borate buffer (pH 8.5) with a 10% (v/v) of acetonitrile, employing a voltage of 30 kV and a temperature of 25 °C. This separation medium enabled the total resolution of eight compounds and the partial resolution of two of the analytes, di-n-octyl phthalate (DNOP) and diethyl hexyl phthalate (DEHP) (Rs ~ 0.8), in only 12 min. The analytical characteristics of the developed method were studied showing their suitability for the determination of these compounds in commercial perfumes. In all the analyzed perfumes the most common phthalate was diethyl phthalate (DEP) that appeared in ten of the fifteen analyzed products. Also dimethyl phthalate (DMP), diallyl phthalate (DAP), dicyclohexyl phthalate (DCP), and di-n-pentyl phthalate (DNPP) were found in some of the analyzed samples.     

Accurate determination of the number density of G-phase precipitates in thermally aged duplex stainless steel

G-phase precipitation in the ferrite phase in thermally aged duplex stainless steel (DSS) was investigated. A needle-shaped sample of DSS aged at 673?K for 5000?h was observed by transmission electron microscopy (TEM), and subsequently by atom probe tomography (APT). The precipitates of the G-phase observed by TEM corresponded well to clustering atoms observed by APT. On the other hand, regarding the precipitates of the G-phase that formed in an earlier stage of aging, the present study suggests that not all the precipitates can be detected by TEM. A large area of DSS aged at 673?K for 5000?h containing both the ferrite and austenite phases was observed. The number density of precipitates of the G-phase in the ferrite phase was small in the vicinity of the phase boundary and increased with the distance between the phase boundary and each field of view. The number density reached an almost constant value at a distance of approximately 4?µm from the phase boundary. The suppression of G-phase precipitation in the vicinity of the phase boundary is discussed in terms of the depletion of alloying elements that comprise the G-phase.     

Ag掺杂p型ZnO薄膜及其同质结的光电性质

采用磁控溅射技术在Si基片上生长了Ag掺杂的ZnO薄膜,XRD测试表明所得薄膜结晶性质良好,未出现Ag的分相。未掺杂和Ag掺杂氧化锌薄膜的低温(10K)光致发光(PL)谱显示:Ag的掺入使得中性施主束缚激子发射(D0X)显著减弱,并且在3.315eV处观测到了与Ag有关的施主-受主对(DAP)发射,受主缺陷的形成归因于掺入的Ag替位Zn。计算得到受主能级离价带顶约110meV。霍尔效应测得电阻率约0.1Ω.cm,迁移率约36cm2/V.s,空穴浓度约1.7×1018cm-3。在此基础上制备了ZnO∶Ag/ZnO的同质结,I-V测试显示了明显的整流特性,且反向漏电流很小。所有结果表明Ag掺杂的氧化锌薄膜已经转化为p型。     

Recent developments in manufacturing emulsions and particulate products using membranes

Membrane emulsification (ME) is a relatively new technique for the highly controlled production of particulates. This review focuses on the recent developments in this area, ranging from the production of simple oil-in-water (O/W) or water-in-oil (W/O) emulsions to multiple emulsions of different types, solid-in-oil-in-water (S/O/W) dispersions, coherent solids (silica particles, solid lipid microspheres, solder metal powder) and structured solids (solid lipid microcarriers, gel microbeads, polymeric microspheres, core-shell microcapsules and hollow polymeric microparticles). Other emerging technologies that extend the capabilities into different membrane materials and operation methods (such as rotating membranes, repeated membrane extrusion of coarsely pre-emulsified feeds) are introduced. The results of experimental work carried out by cited researchers in the field together with those of the current authors are presented in a tabular form in a rigorous and systematic manner. These demonstrate a wide range of products that can be manufactured using different membrane approaches. Opportunities for creation of new and novel entities are highlighted for low throughput applications (medical diagnostics, healthcare) and for large-scale productions (consumer and personal products).     

Novel asymmetric 3,5‐bis(arylidene)piperidin‐4‐one derivatives: synthesis,crystal structures and cytotoxicity

3,5‐Bis(arylidene)piperidin‐4‐one derivatives (BAPs) display good antitumour activity because of their double α,β‐unsaturated ketone structural characteristics. Reported BAPs have generally been symmetric and asymmetric BAPs have been little documented. Three asymmetric BAPs, namely (5E)‐3‐(4‐tert‐butylbenzylidene)‐5‐(4‐fluorobenzylidene)‐1‐methylpiperidin‐4‐one, C₂₄H₂₆FNO, ( 5 ), (5E)‐3‐(4‐tert‐butylbenzylidene)‐5‐(3,5‐dimethoxybenzylidene)‐1‐methylpiperidin‐4‐one, C₂₆H₃₁NO₃, ( 6 ), and (5E)‐3‐{3‐[(E)‐(2,3‐dihydroxybenzylidene)amino]benzylidene}‐5‐(2‐fluorobenzylidene)‐1‐methylpiperidin‐4‐one, C₂₇H₂₃FN₂O₃, ( 12 ), were generated by Claisen–Schmidt condensation. They are characterized by NMR and FT–IR spectroscopies, and elemental analysis. Single‐crystal structure analysis reveals that the two arylidene rings on both sides of the BAP structures adopt an E stereochemistry of the olefinic double bonds and the compounds are E,E isomers. Molecules of ( 5 ) and ( 12 ) generate one‐dimensional chains through intermolecular hydrogen bonds, while compound ( 6 ) generates a two‐dimensional network through hydrogen bonds. Preliminary cytotoxicities toward human liver hepatocellular carcinoma cell line (HepG2), human acute mononuclear granulocyte leukaemia (THP‐1) and human normal hepatical cell line (LO2) were evaluated.