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81.
Han QB Lee SF Qiao CF He ZD Song JZ Sun HD Xu HX 《Chemical & pharmaceutical bulletin》2005,53(8):1034-1036
From the antibacterial fraction of the roots of Garcinia kola, 3',4',4',5,5',7,7'-heptahydroxy-3,8'-biflavanone (GB1) was isolated as the major constituent, whose interesting conformations were studied on the basis of its 1D and 2D NMR spectra obtained at different temperatures and in different solvents. GB1 showed antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) with MIC of 32 and 128 microg/ml, respectively. 相似文献
82.
Jixin Qiao Petra Lagerkvist Ilia Rodushkin Susanna Salminen-Paatero Per Roos Syverin Lierhagen Karl Andreas Jensen Emma Engstrom Yann Lahaye Lindis Skipperud 《Journal of Radioanalytical and Nuclear Chemistry》2018,315(3):565-580
Inductively coupled plasma mass spectrometry (ICP-MS) techniques are widely used for determination of long-lived radionuclides and their isotopic ratios in the nuclear fields. Uranium (U) and Plutonium (Pu) isotopes have been determined by many researchers with ICP-MS due to its relatively high sensitivity and short measurement time. In this work, an inter-laboratory comparison exercise among the Nordic countries was performed, focusing on the measurement of U and Pu isotopes in certified reference materials by ICP-MS. The performance and characters of different ICP-MS instruments are evaluated and discussed in this paper. 相似文献
83.
The Hydrogen Evolution Reaction in Alkaline Solution: From Theory,Single Crystal Models,to Practical Electrocatalysts 下载免费PDF全文
Dr. Yao Zheng Dr. Yan Jiao Anthony Vasileff Prof. Shi‐Zhang Qiao 《Angewandte Chemie (International ed. in English)》2018,57(26):7568-7579
The hydrogen evolution reaction (HER) is a fundamental process in electrocatalysis and plays an important role in energy conversion for the development of hydrogen‐based energy sources. However, the considerably slow rate of the HER in alkaline conditions has hindered advances in water splitting techniques for high‐purity hydrogen production. Differing from well documented acidic HER, the mechanistic aspects of alkaline HER are yet to be settled. A critical appraisal of alkaline HER electrocatalysis is presented, with a special emphasis on the connection between fundamental surface electrochemistry on single‐crystal models and the derived molecular design principle for real‐world electrocatalysts. By presenting some typical examples across theoretical calculations, surface characterization, and electrochemical experiments, we try to address some key ongoing debates to deliver a better understanding of alkaline HER at the atomic level. 相似文献
84.
Maximizing the Number of Interfacial Sites in Single‐Atom Catalysts for the Highly Selective,Solvent‐Free Oxidation of Primary Alcohols 下载免费PDF全文
Tianbo Li Dr. Fei Liu Yan Tang Dr. Lin Li Prof. Shu Miao Yang Su Dr. Junying Zhang Prof. Jiahui Huang Hui Sun Prof. Masatake Haruta Prof. Aiqin Wang Prof. Botao Qiao Prof. Jun Li Prof. Tao Zhang 《Angewandte Chemie (International ed. in English)》2018,57(26):7795-7799
The solvent‐free selective oxidation of alcohols to aldehydes with molecular oxygen is highly attractive yet challenging. Interfacial sites between a metal and an oxide support are crucial in determining the activity and selectivity of such heterogeneous catalysts. Herein, we demonstrate that the use of supported single‐atom catalysts (SACs) leads to high activity and selectivity in this reaction. The significantly increased number of interfacial sites, resulting from the presence of individually dispersed metal atoms on the support, renders SACs one or two orders of magnitude more active than the corresponding nanoparticle (NP) catalysts. Lattice oxygen atoms activated at interfacial sites were found to be more selective than O2 activated on metal NPs in oxidizing the alcohol substrate. This work demonstrates for the first time that the number of interfacial sites is maximized in SACs, providing a new avenue for improving catalytic performance by developing appropriate SACs for alcohol oxidation and other reactions occurring at metal–support interfacial sites. 相似文献
85.
Man-Zhu Zhao Dong-Bing Cheng Zhao-Ru Shang Lei Wang Zeng-Ying Qiao Jing-Ping Zhang Hao Wang 《高分子科学》2018,36(10):1103-1113
The interfacing study of biopolymer and supramolecular chemistry enables a better understanding of fundamental biochemical processes and the creating of new high-performance biomaterials. In this review, we introduced an “in vivo self-assembly” strategy which means in situ construction of functional self-assembled superstructures in specific physiological or pathological conditions in cell, tissue or animal levels that exhibit diverse biomedical effects. By using this strategy, unexpected phenomena and insights, e.g, assembly/aggregation induced retention (AIR) effect have been demonstrated where the self-assembled nanostructures showed extraordinary enhanced accumulation and retention of therapeutics in targeted sites. 相似文献
86.
87.
浙江大学海外教师主导的研究生全英文课程建设项目于2013年开始进行建设,高分子科学与工程学系借此契机,在原研究生课程《高分子材料表面与界面》的基础上,邀请德国海德堡大学M.Grunze教授进行全英文教学。本课程旨在建设与国际接轨的,具有基础性、前沿性、交叉性且受益面广的全英文课程,提高高分子专业研究生的专业水平,扩大学生知识面,提高英语交流水平,同时培养一支具有国际化教学能力的中青年师资队伍。本文就该课程三年建设期以来的教学内容形式、课堂管理、学生学习体验等方面进行了总结,并针对研究生学习过程中存在的问题,结合当前我国研究生的基本现状,提出了一系列教学经验。 相似文献
88.
Yong-Ming Cui Lu Qiao Yi Li Qian Wang Wu Chen Wen-Xuan Yan 《Transition Metal Chemistry》2017,42(1):51-56
A series of dioxomolybdenum(VI) complexes with similar hydrazone ligands have been prepared, specifically [MoO2L1(MeOH)] (1), [MoO2L2(MeOH)] (2) and [MoO2L3(MeOH)] (3), where L1, L2 and L3 are the dianionic forms of 2-chloro-N′-(2-hydroxybenzylidene)benzohydrazide, 2-chloro-N′-(2-hydroxy-5-methylbenzylidene)benzohydrazide and N′-(3-bromo-5-chloro-2-hydroxybenzylidene)-2-chlorobenzohydrazide, respectively. The complexes were characterized by physicochemical and spectroscopic methods and also by single-crystal X-ray determination. The hydrazone ligands coordinate to the Mo atoms through their phenolate O, imine N and enolic O atoms. The Mo atoms are six-coordinated in octahedral geometries. The complexes show high catalytic activities and selectivities in the epoxidation of cyclohexene with tert-butylhydroperoxide as primary oxidant. 相似文献
89.
以交联密度不同的同类轮胎胎面胶A1和A2为研究对象,通过动态拉伸实验得到储能模量及损耗模量随频率变化的曲线.建立了黏弹性广义Maxwell模型来定量分析不同温度的橡胶在不同频率的动态载荷下的能量损耗.采用非线性规划的方法分别在低频(10~25 Hz)及高频(25~60 Hz)下拟合模量-频率曲线,得到黏弹性广义Maxwell模型的参数值.采用有限元软件Abaqus模拟胎面胶动态拉伸过程并计算胎面胶的损耗角正切,得到不同温度下胎面胶的损耗角正切随激振频率的变化规律,通过和实验结果的比较证明文中所述黏弹性广义Maxwell模型及其参数获取方法可准确应用于胎面胶的动态拉伸性能分析.预测了在不同温度及频率下每一循环载荷周期中胎面胶的应力-应变迟滞回线以及单位体积胶料的能量损耗,阐释了不同温度下的胎面胶的能量损耗随频率的变化规律,同时结合2种胎面胶的交联密度测试数据分析了胶料的构效关系. 相似文献
90.
Antibacterial membranes based on chitosan and quaternary ammonium salts modified nanocrystalline cellulose 下载免费PDF全文
Ying Liu Mei Li Mingyu Qiao Xuehong Ren Tung‐Shi Huang Gisela Buschle‐Diller 《先进技术聚合物》2017,28(12):1629-1635
Etherification of nanocrystalline cellulose (NCC) with three kinds of quaternary ammonium salts epoxypropyltrimethylammonium chloride, N,N‐dimethyl‐N‐dodecyl‐N‐(1,2‐epoxypropyl) ammonium chloride (DMDEPAC), and N,N‐dimethyl‐N‐octadecyl‐N‐(1,2‐epoxypropyl) ammonium chloride (DMOEPAC) was successfully performed via a nucleophilic addition reaction. The synthesized DMDEPAC and DMOEPAC were characterized by nuclear magnetic resonance. The modified NCC particles, NCC epoxypropyltrimethylammonium chloride, NCC‐DMDEPAC, and NCC‐DMOEPAC, were characterized by energy dispersive spectrometer. Nanocomposite films based on chitosan (CS) containing quaternary ammonium salts modified NCC were prepared with nanoparticle loadings of 5.0, 7.5, and 10.0%, respectively. The effect of nanoparticle content on the tensile strength of composite films was studied. The results indicated that the films with 5.0% nanoparticle loading exhibited the biggest increase in tensile strength. Surface morphology, smoothness, and antibacterial properties of composite films containing 5% modified NCC were also studied. CS/NCC‐DMDEPAC‐5.0 and CS/NCC‐DMOEPAC‐5.0 displayed excellent biocidal abilities against both Gram‐positive Staphylococcus aureus (ATCC 6538) and Gram‐negative Escherichia coli O157:H7 (ATCC 43895). The bio‐based nanocomposite films with increased mechanical strength and excellent antibacterial properties show great potential as food packaging materials. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献