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CCS chemistry 2024年第4期6卷 1060-1070页

作者： Sifan Li Hai-Wu Du Paul W.Davies Wei Shu Department of chemistry Shenzhen Grubbs InstituteSouthern University of Science and TechnologyShenzhen 518055Guangdong School of chemistry University of BirminghamEdgbastonBirmingham B152TT

Sterically congestedα-tertiary primary amines are ubiquitous substructures in pharmaceutical and agrochemical agents yet are challenging to ***,straightforward photoredox-catalyzed access to structurally diverseα,α,α-trisubstituted primary amines from denitrogenative alkylarylation or dialkylation of vinyl azides with N-hydroxyphthalimide(NHPI)esters and cyanoarenes or aryl aldehydes has been *** use of vinyl azide as a precursor to a primary aminewas enabled by the dual role of the Hantzsch ester to form an electron donor-acceptor complex and serve as a sacrificial *** strategy provides a modular synthesis ofα-tertiary primary amines,including unprotected 1,2-amino alcohols,from simple materials with excellent functional group *** synthetic applicability of this method was demonstrated by streamlined access to 2,2-disubstituted *** investigations support two parallel reductive photocatalytic cycles allowing for the denitrogenative alkylarylation or dialkylation of vinyl azides via decarboxylative radical addition followed by heteroradical cross-coupling betweenα-amino radicals and aryl anion radicals or ketyl anion radicals.

关键词： photocatalysis α-tertiary primary amines 1 2-amino alcohols vinyl azide electron donor-acceptor complex

Carbene-catalyzed enantioselective seleno-Michael addition as access to antimicrobial active Se-containing heterocycles

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Science China chemistry 2024年第7期67卷 2199-2205页

作者： Hongyan Long Sha Zhao Chunyan Jian Xiuli Wu Fengfei Lu Minghong Liao Fengrui Che Xingxing Wu Yonggui Robin Chi State Key Laboratory of Green Pesticide Key Laboratory of Green Pesticide and Agricultural BioengineeringMinistry of EducationGuizhou UniversityGuiyang 550025China School of chemistry Chemical Engineeringand BiotechnologyNanyang Technological UniversitySingapore 637371Singapore

Organoseleniums exhibit a diverse set of biological activities that are pivotal for drug discovery and are widely explored in synthetic chemistry and material *** many transformations have been developed for non-enantioselective C–Se bond formations,the catalyst-controlled stereoselective preparation of chiral organoseleniums continues to be of considerable *** particular,there are limited studies on the enantioselective seleno-Michael addition reactions to access chiral selenium functional ***,we disclose a carbene-catalyzed highly enantioselective nucleophilic C–Se bond construction through formal[3+3]annulations between selenocarboxamides and bromoenals,affording seleno-thiazinone products with good yields and excellent *** choice of a weak inorganic base was pivotal to suppressing the unproductive racemization and decomposition of the selenium ***,the catalytically generated chiral selenium-containing heterocyclic products feature remarkable antimicrobial activities that could serve as promising lead scaffolds for further agrochemical development.

关键词： seleno-Michael addition organocatalysis N-heterocyclic carbene seleno-heterocycles antimicrobial activity

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Effect of inorganic additives on physical and chemical properties of PEO-LiClO_4 polymer electrolyte for lithium-ion batteries

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Journal of Harbin Institute of technology(New Series) 2009年第6期16卷 869-872页

作者：顾大明李已才杨柳王淑堂 dept. of chemistry Harbin Institute of Technology

Inorganic additives-added PEO-based solid composite polymer electrolyte (SCPE) was prepared using solution casting method. The effects of LiNi0.8Co0.2O2 on the physical and chemical properties of the electrolyte were investigated. The products were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR) and differential scanning calorimetry (DSC). The electrochemical performances of SCPE were measured. Results show that properties of the SCPE are improved significantly by adding LiNi0.8Co0.2O2 into PEO polymer electrolyte. Its conductivity reaches 5×10-4 S/cm(25 ℃) while retaining good mechanical and processing properties.

关键词：聚合物电解质无机添加剂化学性质 PEO 锂离子电池物理傅立叶变换红外光谱仪氯酸锂

Statistical Characteristics of Metastable Pitting of 316 Stainless Steel

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Journal of Materials Science & technology 2000年第3期16卷 286-290页

作者： Yu ZUO, Haiou DU and Jinping XIONG (dept. of Applied chemistry, Beijing University of Chemical technology, Beijing 100029, China) dept. of Applied chemistry Beijing University of Chemical Technology Beijing 100029 China

The statistical characteristics of the current fluctuations during metastable pitting of 316L stainless steel in NaCI solution were studied using potentiostatic method. The growth rates and peak currents of metastable pits followed log-normal distributions. As potential and chloride concentration increased, both growth rate and peak current of metastable pits increased. The lifetime of metastable pits also followed log-normal distribution, and was almost not affected by potential. Higher growth rates did not definitely result in larger metastable pits. A certain propagation rate range was found beneficial for the micropit to remain growth. At constant potential, the maximum peak currents in different time intervals during a potentiostatic test followed extreme distribution. The statistical characteristics of metastable pitting may be used to predict the tendency of pitting corrosion.

关键词： Statistical Characteristics of Metastable Pitting of 316 Stainless Steel

Diffusion of Hydrogen in Amorphous NiCrFeSiB Alloy

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Journal of Materials Science & technology 1996年第1期12卷 15-18页

作者： Zuo, Y Yang, B Xu, RS dept. of Applied chemistry Beijing University of Chemical Technology Beijing 100029 China

The diffusion of hydrogen in amorphous NiCrFeSiB alloy has been studied by electrochemical method. In the temperature range of 20 similar to 50 degrees C, diffusion coefficient of hydrogen in the alloy follows the equation: D(cm(2)/s) = 9.27x10(-8) exp(-53.4 kJ/RT). At room temperature the diffusion coefficient D and the solubility C-0 are 6.125 x 10(-12) cm(2)/s and 0.007 mol/cm(3), respectively. When As2O3 is added into the cathodic solution or the charging current density is increased, the diffusion coefficient and solubility increase, and the diffusion activation energy decreases. The influence of amorphous structure on diffusion and solution of hydrogen is discussed.

关键词： Nickel alloys

Effects of Nitrogen Doping on Microstructure and Photocatalytic Activity of Nanocrystalline TiO_2 Powders

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Journal of Wuhan University of technology(Materials Science) 2007年第3期22卷 457-461页

作者：杨志远 dept. of chemistry and Chemical Engineering Xi’an University of Science and Technology

Nitrogen-doped TiO2 nanocrystalline powders were prepared by hydrolysis of tetrachloride titanium （TiCl4） in a mixed solution of ethanol and ammonium nitrate （NH4NO3） at ambient temperature and atmosphere followed by calcination at 400 ℃ for 2 h in air. FTIR spectra demonstrate that amine group in original gel is eliminated by calcination, and the TiO2 powder is liable to absorb water onto its surface and into its capillary pore. XRD and SEM results show that the average size of nanocrystalline TiO2 particles is no more than 60 nm and with increasing the calcination temperature, the size of particles increases. XPS studies indicate the nitrogen atom enters into the TiO2 lattice and occupies the position of oxygen atom. The nitrogen doping not only depresses the grain growth of TiO2 particles, but also reduces the phase transformation temperature of anatase to futile. The photocatalytic activity of the nitrogen-doped TiO2 powders has been evaluated by experiments of photocatalytic degradation aqueous methylene blue.

关键词： titanium oxide nitrogen doping photocatalytic activity nanocrystalline methylene blue

Electro-catalytic oxidation of phenol with Ti-base lead dioxide electrode

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Journal of Harbin Institute of technology(New Series) 2003年第1期10卷 19-23页

作者：王东田魏杰于秀娟杨红 dept. of Applied chemistry Harbin Institute of Technology

The Ti base PbO 2 electrode prepared by electrodeposition of PbO 2 on the surface of titanium was used for electro catalytic oxidation of phenol in waste water. The experimental results show that the electrodeposition of PbO 2 at a higher current density for a short time, then followed by a lower current density can get a compact and combinative PbO 2 layer. The properties of a Ti/PbO 2 electrode with an interlayer of oxide are the best. When this kind of electrode is used to treat phenol containing waste water, the phenol removal rate is higher and the slot voltage is lower. In addition, by using the phenol removal rate as an index, the influences of electrolysis current density, mass transfer condition and pH were studied and the optimal condition was confirmed.

关键词：废水处理 PbO2电极钛基诱导氧化物电极 Ti 苯酚污染电极催化

Electric characteristics of Nd_2O_3 doped BaTiO_3 ceramics

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Journal of Harbin Institute of technology(New Series) 2003年第4期10卷 388-391页

作者：郝素娥韦永德 dept. of Applied chemistry Harbin Institute of Technology

Nd2O3 doped BaTiO3ceramics（the additive content was respectively 0.001, 0.002, 0.003, 0.005, 0.01 molar ratio）were prepared by Sol-Gel method to study their dielectric characteristics and electric conductivities through X-ray photoelectron spectrum （XPS）. The results showed that the dielectric characteristics of Nd2O3 doped BaTiO3 ceramics were improved by doping. When Nd2O3 content was 0.003 mol, the results were even better, the dielectric constant was increased, the dielectric loss was decreased, the Curie-temperature （Tc） was 110 ℃, and the frequency characteristic was also good. The resistivity of Nd2O3 doped BaTiO3 ceramics was lower than that of pure BaTiO3 ceramics, when Nd2O3 content was 0.001 mol,the resistivity was （2.364×）108 Ω·m, the smallest. The grain resistance of Nd2O3 doped BaTiO3 ceramics exhibited NTC effect, but the grain boundary resistance showed PTC effect, and the grain boundary resistance was larger than that of the grain resistance, so the PTC effect originated from the grain boundary. The analysis of the element binding energy through X-ray photoelectron spectrum were indicated that the quantivalence of Ba2+and Ti4+in Nd2O3 doped BaTiO3 ceramics was variable, and resulted in the improvement of the conductibility of BaTiO3 ceramics.

关键词： BaTiO3 导电性 Nd2O3 陶瓷材料 X射线光电子光谱

Microstructure of Co-Ni-Al2O3 Composite Coatings by Electroforming

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Journal of Materials Science & technology 2003年第Z1期19卷 133-134页

作者： Gang WU Ning LI Derui ZHOU Kurachi Mitsuo dept. of Applied chemistry Harbin Institute of Technology Harbin 150001 China1 Dept. of Applied Chemistry Harbin Institute of Technology Harbin 150001 China1 Dept. of Applied Chemistry Harbin Institute of Technology Harbin 150001 China1 Faculty of Engineering Kyoto University Kyoto 606-8283 Japan

The metal matrix composite coatings of Co-Ni-Al2O3 were studied by electrolytic codeposition of Co-Ni alloys and Al2O3 on a Cu substrate from a sulfamate electrolyte containing Al2O3 particles. It was illustrated from the examined results of SEM, AFM and XRD that surface morphology and microstructure of Co-Ni-Al2O3 coatings appear to be mainly influenced by variations in Co content. The high Co content coatings with hcp lattice structure have a more uniform and fine structure than that of low Co content coatings with fcc lattice structure. The codeposition of Al2O3 particles in Co-Ni alloys can not change the phase structure of solid solution, only affects the growth and orientation of crystal planes and mostly increase the d value of lattice.

关键词： Electroforming, Composite coatings, Cobalt-Ni alloys, Alumina

Ecological Risk Assessment of Heavy Metals Concentrations in Topsoil of Makurdi and Its Environs

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Journal of Geoscience and Environment Protection 2023年第8期11卷 49-64页

作者： Ada Florence Ogli Adams Udoji Itodo Raymond Ahulle Wuana Rufus Sha’Ato Department of chemistry Akawe Torkula Polytechnic Makurdi Benue State Nigeria Department of chemistry/Centre for agrochemical technology Joseph Sarwuan Tarka University Makurdi Benue State Nigeria

This work examined the concentrations of As, Cd, Cr, Hg and Pb pollution in soil and estimated the potential ecological risks of these metals in Makurdi and its environs, using established pollution indices. The information derived from pollution indices will help to assess the extent, and intensity of anthropogenic contaminant deposition on surface soil in the study area. The soil samples were collected from sixteen (16) locations across the investigated sites, sampled as appropriate and treated using established methods and analyzed using atomic absorption spectrometry (AAS). The findings have revealed that the concentrations of the metals in the topsoil samples were arranged in the sequence from increasing to decreasing order thus: Cr > Pb > Cd > Hg > As. It was observed that the pollution levels of As and Hg were insignificant, while, the level of pollution caused by Cd, Cr and Pb ranged from low level of contamination to high level of contamination across the investigated sites, except, for the control site (BZ) whose pollution level was insignificant with respect to the heavy metals studied. The results could be used as preliminary baseline data for heavy metal concentrations for future assessment and monitoring. Therefore, there is an urgent need to effect mitigation measures to reduce the ecological environmental risks, taking into consideration that human activities which are the main source of pollutants are still ongoing in the study area.

关键词： Pollution Contamination Single Indices Integrated Indices Makurdi