The thermal conductivity of alumina nanoparticles dispersed in ethylene glycol

The thermal conductivities of several nanofluids (dispersions of alumina nanoparticles in ethylene glycol) were measured at temperatures ranging from 298 to 411 K using a liquid metal transient hot wire apparatus. Our measurements span the widest range of temperatures that have been investigated to date for any nanofluid. A maximum in the thermal conductivity versus temperature behavior was observed at all mass fractions of nanoparticles, closely following the behavior of the base fluid (ethylene glycol). Our results confirm that additional temperature contributions inherent in Brownian motion models are not necessary to describe the temperature dependence of the thermal conductivity of nanofluids. Our results also show that the effect of mass or volume fraction of nanoparticles on the thermal conductivity of nanofluids can be correlated using the Hamilton and Crosser or Yu and Choi models with one adjustable parameter (the shape factor in the Hamilton and Crosser model, or the ordered liquid layer thickness in the Yu and Choi model).     

Laser-Induced Fluorescence (LIF) Probe for <Emphasis Type="Italic">In-situ</Emphasis> Nitric Oxide Concentration Measurement in a Non-thermal Pulsed Corona Discharge Plasma Reactor

Laser-induced fluorescence (LIF) is an effective in-situ probe for NO concentrations below 300 ppm in a non-thermal plasma reactor. A new method has been developed to measure in-situ NO concentration in the reactor discharge region using a long-time—on the order of seconds—averaged fluorescence detection. This method, for quantifying NO concentration in a nonthermal plasma reactor, is simpler than a short-time—on the order of nanoseconds—fluorescence detection. For accurate measurement based on the new method, the LIF intensity must be close to the corona-induced fluorescence (CIF) intensity; the CIF intensity serves as a guide in selecting the LIF intensity. We find that a kinetic model proposed earlier works for two-tube reactors and represents the NO concentration in the middle of the reactor, which verifies the assumption of gas plug flow.     

Synthesis of four diastereomeric 3,5-dialkoxy-2,4-dimethylalkanals by a simple extension of the non-aldol aldol process to bis(propionates)

[formula: see text] The synthesis of all four diastereomers of bis(propionates), 3,5-dialkoxy-2,4-dimethylalkanals, by non-aldol aldol chemistry is described. The epoxy alcohols (3, 4) were converted into the mesylates (9, 11) which were cleanly rearranged to the desired 3,5-bis(oxygenated)-2,4-dimethylalkanals (10, 12) in high yield. The epoxy mesylates (13, 16) gave the desired products (14, 17) in good yield on treatment with TMSOTf and a hindered base.     

高分子固体电解质研究进展

高分子固体电解质具有质轻、粘弹性了、易成膜等许多无机电解质和有机溶剂电解质所不可比拟的优点，近年来得到了很大的发展，这种新型材料的应用主要集中开发全固态锂电池和锂离子电池。本文对ＳＰＥ的电性能，离子传导特性以及提高ＳＰＥ性能的途径等作了综述，并对其发展前景作了简要探讨。     

射频磁控溅射CNx薄膜的结构与衬底温度关系的研究

使用射频磁控溅射方法在不同衬底温度下（ts=室温，350，500℃）于Si(001)衬底上沉积了CNx膜，并利用拉曼（Raman)光谱、傅里叶变换红外光谱（FTIR）及X射线衍射光电子能谱（XPS）对CNx膜的化学结合状态与温度的关系进行了研究。Raman光谱结果表明，随衬底温度（ts) 增加，D带向低频方向移动，G带向高频方向移动；它们的半高宽分别由375和150cm^-1减小至328和142cm^-1；ID／IG由3．76减小至2.88。FTIR谱中除无序D带（1400cm^-1)和石墨G带（1570cm^-1)外，还有－700cm^-1,～2210cm^-1(C=N),2330cm^-1(C-O)及3255－3351cm^-1(N-H)等峰。XPS测试结果表明：随衬底温度增加，N与C的物质的量比由0.49下降至0.38，sp^2(C-N)组分与sp^3(C-N)组分强度比呈增大趋势。低温（350℃）退火并未对CNx膜的化学结合状态产生较大影响；高温（900℃）退火样品则显示出较好的结晶化程度。     

Convenient and Efficient Synthesis of L—Rhamnopyranosyl Phosphoramidates via H—Phosphonate

It is known that saccharides linked to proteins via a phosphoester hinge can function as immunological determinants. Under regular physiological conditions, it has been suggested that the role of phosphonate group is to direct the protease towards basic substrates1. Phosphoramidon a, which was isolated from a culture filtrate, is a potent inhibitor of the thermolysin, a metallo-endopeptidase. It is a glycosylated dipeptide, which has a L-rhamnose attached to the N-terminal of Leu-Trp dipep…     

Chemical species produced in the reaction between ethanedial (glyoxal) and 5-amino-1,10-phenanthroline and their iron(II) complexes: preparation and some spectrometric studies

Chemical species obtained by reaction of 5-amino-1, 10-phenanthroline with ethanedial (glyoxal) are reported with regard to their preparation, chemical composition and spectrometric characterization (UV-visible, infrared and liquid secondary ion mass spectrometry). Products of the reaction are postulated to be a mixture of species with molecular weights of 339, 371,480 and 524 u. Chemical reactions leading to these products and possible structural formulas for each of these species are presented. The iron complexes of these ligands, because of their extremely low solubility in most solvents, find application as redox mediators when incorporated in carbon paste electrodes, particularly for sensing in continuous-flow systems.     

聚醚氨酯的氧化及其接枝共聚合的研究

本文研究了在聚醚氨酯表面上进行接枝共聚合的新方法。首先在聚醚氨酯薄膜上通过过氧化氢光氧化引入过氧化氢基,然后在还原剂亚铁盐或N,N-二甲基对甲苯胺的作用下引发丙烯酰胺接枝共聚合,反应具有低温快速的特点。产物经吸水性实验及扫描电子显微镜观察均证实了是一接枝共聚物。通过模型化合物的研究证明,接枝反应具有较高的选择性,接枝共聚占优势地发生在聚醚软段上,接枝地点很可能就在醚键旁的α-碳原子上。     

Construction of a 2,6-difunctionalized 2-methyl-2H-1-benzopyran library by using a solid-phase synthesis protocol

[reaction: see text] A library containing 1200 analogues of 2,6-difunctionalized 2-methyl-2H-1-benzopyran was constructed by using a solid-phase synthesis protocol. Polymer-bound 6-amido-, 6-sulfonamido-, and 6-uredo-functionalized 2-hydroxymethyl-2-methylbenzopyrans 10 were prepared as part of a first-generation diversification step by employing reactions of respective acid halides, sulfonyl chlorides, and isocyanates with the amine precursor 7. Transformations of the resin-bound intermediates 10 by reactions with alkyl and acid halides were then used to produce a diverse series of 2,6-difunctionalized 2-methyl-2H-1-benzopyran analogues 12 and 14.