Electrodeposition and characterization of Zn–Sn alloy coatings from a deep eutectic solvent based on choline chloride for corrosion protection

With the aim of obtaining high corrosion resistant Zn–Sn alloy coatings from an ionic liquid, the effects of electrodeposition potential and electrolyte composition on the electrodeposition behavior, film composition, morphology and corrosion performance were investigated. Cyclic voltammograms indicate that Zn and Sn were co‐deposited at distinct reduction potentials as pure Zn and Sn elements. In addition, the phase composition analysis also showed that the obtained Zn–Sn alloy deposits (8 wt.%–45 wt.% Zn) consist of a two‐phase mechanical mixture of small aggregates of Zn and Sn metals. The Zn content of the alloy significantly increases as the electrodeposition potential and electrolyte Zn (II)/Sn (II) ratio increase. The corrosion performance study of the obtained Zn–Sn coatings showed that they have a passivation behavior and their corrosion resistance increases as the alloy‐Sn content increases. To improve their morphological properties, ethylene diamine tetraacetic acid additive was introduced into the electrolyte and greatly improved the morphology and corrosion resistance of the deposits. For the first time, it was shown that high corrosion resistance Zn–Sn coatings can be obtained from ionic liquids. Copyright © 2014 John Wiley & Sons, Ltd.     

Artanomadimers A–F: six new dimeric guaianolides from Artemisia anomala

A novel dimeric guaianolide with an unprecedented skeleton, named artanomadimer A (1), and five new analogues, artanomadimers B–F (2–6), were isolated from the aerial parts of Artemisia anomala. Their structures and stereochemistry were elucidated by extensive spectroscopic methods, and the absolute stereochemistry of compound 4 was confirmed by X-ray crystallographic analysis. Artanomadimer A (1) is probably formed through a Diels–Alder reaction with the new carbon–carbon bond formation of C-11/C-2′ and C-13/C-5′ based on its structure. A cytotoxic evaluation showed that compounds 1 and 6 exhibited significant inhibitory effects against the cell growth of BGC-823 tumor cell lines with IC₅₀ values of 2.71 and 6.25 μM, respectively.     

Application of polarity switching in the identification of the metabolites of RO9237

Polarity switching mass spectrometry is an efficient way to collect structural data on drug metabolites. The value of this approach is illustrated with the in vitro metabolism of RO9237. Metabolites are identified by positive and negative electrospray ionization (ESI) full scan mass spectrometry, MS/MS and MS(3) using unlabelled and (14)C-radiolabelled versions of the drug. Comparison of the relative detectability of these metabolites by +ESI and -ESI shows that neither ESI mode is universal. It is advantageous to screen for metabolites using both positive and negative ionization modes. This is especially true for phase II metabolism which tends to make molecules more polar and often more acidic. Identification of phase II metabolites also benefits greatly from MS(3) experiments because the conjugating groups typically are cleaved in MS/MS and information on the core structure is only obtained in MS(3). A special case of phase II metabolism is the generation of glutathione (GSH) conjugates from reactive metabolites. The detection of GSH conjugates also benefits from generating both positive and negative ESI mass spectral data.     

Novel calix[4]arene-thiacrown ether for selective and efficient extraction of Ba(II), Pb(II), and Hg(II)

A di-ionizable p-tert-butylcalix[4]arene-1,3-thiacrown-5 ether extractant was synthesized. Its cone conformation and polyether ring attachment regioselectivity were verified by NMR spectroscopy. The metal ion-complexing properties of this ligand were evaluated by solvent extractions of metal cations from aqueous solutions into chloroform. The ligand was found to be an efficient extractant with Ba²⁺ selectivity in competitive solvent extraction of alkaline earth metal cations. It also exhibits high extraction ability for Pb²⁺ and for Hg²⁺ in single species solvent extractions.     

单柱离子色谱法同时测定磷酸中痕量钠（Ⅰ）和铁（Ⅲ）

以酒石酸－乙二胺为淋洗液的单柱离子色谱法同时测定磷酸中痕量钠（Ⅰ）和铁（Ⅲ）。淋洗液最佳浓度为４．０ｍｍｏｌ．Ｌ￣（－１）、酒石酸／１．０ｍ　ｍｏｌ·Ｌ￣（－１）乙二胺。最低检测限为Ｎａ￣＋０．０５μｇ／ｍＬ、　Ｆｅ３＋　０．４５μｇ／ｍＬ。电导检测灵敏度为２．０μｇ／ｃｍ。线性范围Ｎａ￣＋、Ｆｅ３＋０．２～１．５×１０３μｇ／ｍＬ、２．５～１．０×１０３μｇ／ｍＬ。相对平均偏差Ｎａ￣＋为２．０３％、Ｆｅ３＋为０．８３％。平均回收率Ｎａ￣＋为９８．２６％、Ｆｅ３＋为９７．６２％。本法简便、快速、准确、选择性好。     

CAHN－2000磁天平的调试与数据处理系统的研制

叙述了ＣＡＨＮ－２０００磁天平（美国）调试过程中如何解决液氮温区的测试，自制了磁天平与计算机的接口，编写了数据采集、处理和控制等高原 软件，节省了几万美元，部分指标超过原配套水平，三年来仪器在对国同外开放过程中，液氮温区的工作一直正常，实测了上千个样品，提供的数据已撰写数十篇文章在国内外刊物上发表。由此说明，要充分发挥进口仪器的使用效率，必须对仪器的工作原理、结构特点有透乇的了解，同时要有相当的自     

质子交换膜燃料电池电流密度分布特性和研究展望

质子交换膜燃料电池具有无污染、噪声低、能量密度高、燃料转换效率高、响应速度快的显著优点,得到了迅速发展,但寿命仍然是制约其大规模商业化的重要原因。局部电流密度作为质子交换膜燃料电池运行过程中的重要参数,既能作为电池运行过程中的故障诊断和定位工具,提升电池运行的稳定性和和耐久性;又能提供电池运行期间其内部现象的有关信息,为深入理解电池反应机理以及优化电池设计提供有力指导,因此研究局部电流密度具有非常重要的意义。本文介绍并分析了实时原位测量局部电流密度的方法,比较了前人实验所得结果与模拟所得结果,阐述了相关参数对局部电流密度分布的影响机制,回顾并评析了局部电流密度用于燃料电池分析中的实际工作。最后,立足于局部电流密度的研究现状,给出了局部电流密度下一步的研究方向。     

A new rapid multicomponent domino reaction for the formation of functionalized benzo[h]pyrazolo[3,4-b]quinolines

A new multicomponent domino reaction for rapid and regioselective synthesis of highly functionalized benzo[h]pyrazolo[3,4-b]quinolines has been established. The reaction can be conducted by using readily available and inexpensive substrates under microwave irradiation within short periods of 10-26 min. Good to excellent chemical yields (61-91%) and complete regioselectivity have been achieved for 22 examples. Tedious work-up procedure can be avoided due to the direct precipitation of products from the reaction solution. The resulting benzoquinolines have been readily converted into quinoxaline-fused benzo[h]isoxazolo[5,4-b]quinoline analogues by treating with benzene-1,2-diamine under microwave irradiation. The structural assignment has been ambiguously confirmed by X-ray analysis. A new mechanism has been proposed for this new multicomponent domino process.     

Mesoporous Co3O4 monolayer hollow-sphere array as electrochemical pseudocapacitor material

A Co(3)O(4) monolayer hollow-sphere array with mesoporous walls exhibits high pseudocapacitances of 358 F g(-1) at 2 A g(-1) and 305 F g(-1) at 40 A g(-1), as well as excellent cycling stability for application as pseudocapacitors.     

Electrochemiluminescent sensing of dopamine using CdTe quantum dots capped with thioglycolic acid and supported with carbon nanotubes

We have synthesized water-dispersible CdTe quantum dots (QDs) capped with thioglycolic acid. Their quantum yield is higher than 54%. A sensitive electrochemiluminescence (ECL) method was established based on the modification of the composite of the QDs, carbon nanotubes and chitosan on indium tin oxide glass. The sensor displays efficient and stable anodic ECL which is quenched by dopamine. A respective sensor was designed that responds to dopamine linearly in the range of 50?pM to 10?nM, and the detection limit is 24?pM. Dopamine was determined with this sensor in spiked cerebro-spinal fluid with average recoveries of 95.7%.