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Corrosion prevention of sintered Nd-Fe-B magnet by a phosphate chemical conversion treatment

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Rare Metals 2021年第1期40卷 185-189页

作者： Xia Ding xiu-chun wang Kai-Hong Ding Sheng-Li Cui Yong-Cong Sun Mu-Sen Li Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of EducationShandong UniversityJinan 250061China New Material Institute of Shandong Academy of Sciences.Jinan 250014 China Yantai Shougang Magnetic Materials Inc Yantai 265500China

The corrosion-resistant coating formed on the surface of sintered Nd-Fe-B magnet by a phosphate chemical conversion(PCC)treatment was *** morphology,phase composition and thickness of the coating were investigated by field emission scanning electron microscopy(FE-SEM),energy-dispersive spectrometer(EDS),Fourier transform infrared(FTIR)spectrometer and coating thickness *** corrosion behaviour of the phosphated magnet was evaluated by copper sulphate spot test,neutral salt spray test and electrochemical potentiodynamic polarization *** magnetic properties of the phosphated magnet were also *** experimental results show that the phosphate coating has such characteristics as dense granular growth,uniform distribution and thickness range of 10-18μ*** corrosion resistance of the magnet is significantly improved by phosphate coating without losing magnetic ***,this highly efficient PCC was a good way for increasing the corrosion resistance of the sintered Nd-Fe-B magnets.

关键词： Nd-Fe-B magnet Phosphate chemical conversion Microstructure Corrosion resistance

Formation of Ultrafine Apatite Fibers by Sol-gel/Electrospinning

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Chemical Research in Chinese Universities 2007年第3期23卷 366-369页

作者： DING Ya-mei YUAN Xiao-yan ZHAO Jin GUO Wan-chun wang xiu-kui School of Materials Science and Engineering Tianjin University Tianjin 300072 P. R. China

Ultrafine apatite fibers were prepared by electrospinning of sol-gel precursor/poly（ vinyl pyrrolidone）（PVP） solutions followed by subsequent calcination. The as-electrospun and calcinated fibers were observed under a scanning electron microscope and an optical polarizing microscope. Results show that the morphology and the diameter of as-electrospun fibers strongly depend on the viscosity and the surface tension of sol-gel precursor/PVP solutions. After calcination, the smooth as-electrospun fibers shrink and the fiber diameter decreases because of the removal of the polymer. The chemical evolution upon the transformation of the precursor from a gel to the final apatite fibers was investigated by thermogravimetric-differenfial thermal analysis, X-ray diffraction, and Fourier transform infrared spectroscopy. It is thus suggested that the crystalline structure of the calcined fibers is largely influenced by the calcination temperature. After being calcined at 600 ℃, the apatite fibers with a diameter of about 280 nm containing β-tricalcium phosphate were obtained.

关键词： Apatite Ultrafine fiber Sol-gel Electrospinning

STUDIES ON THE SYNTHESIS AND BIOLOGICAL ACTIVITY OF 1-ARYLOXYACETYL-4-AROYLTHIOSEMICARBAZIDE DERIVATIVES

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Chinese Chemical Letters 1993年第1期4卷 5-8页

作者： Ji Chou CHEN Tai Bao WEI xiu chun wang Su You YANG Department of Chemistry Northwest Normal UniversityLanzhou730070 Department of Biology Northwest Normal UniversityLanzhou730070

A series of new 1-aryloxyacetyl-4-aroylthiosemicarbazides were synthesized by means of solid-liguid phase transfer catalysis. The promoting effects of these new compounds on wheat growth were observed.

关键词： STUDIES ON THE SYNTHESIS AND BIOLOGICAL ACTIVITY OF 1-ARYLOXYACETYL-4-AROYLTHIOSEMICARBAZIDE DERIVATIVES Chen

A homopolymolybdate-supported plate-like 2D cobalt network constructed from a new pyrazole-amide-pyridyl ligand: highly electrochemical activity in both capacitive performance and the detection of Cr(Ⅵ)

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Tungsten 2024年第2期6卷 422-427页

作者： xiu-Li wang Yong-Zhen Chen Zhi-Han Chang Yu-chun Lin Jing-Yi Ma College of Chemistry and Materials Engineering Bohai UniversityJinzhou 121013China Professional Technology Innovation Center of Liaoning Province for Conversion Materials of Solar Cell Jinzhou 121013China

By employing a new semi-rigid pyrazole-amide-derived bis(pyridyl)ligand[N,N'-bis(4-picolylamine)-1-hydropyrazole(4-dpap)],a new homopolymolybdate-based two-dimensional(2D)plate-like complex[Co(4-dpap)(H_(2)O)(β-Mo_(8)O_(2)6)1/2](1)has been prepared under solvothermal condition and structurally ***β-Mo_(8)anions are fi xed between the 2D metal–organic networks[Co(4-dpap)(H_(2)O)]n 2n+via hydrogen-bonding *** 1 possesses satisfactory specifi c capacitance of 1512.4 F·g^(−1)(current density:1 A·g^(−1))and good cycling stability(90.8%after 1000 cycles).Moreover,1 represents a promising amperometric sensor for measurement of Cr(Ⅵ)with low detection limit(0.042μmol·L^(−1))and high *** insertion ofβ-Mo_(8)anions between the unique 2D metal−organic networks improves the active area of polyoxometalates,which further promotes electrochemical performance.

关键词： Homopolymolybdate Metal–organic network Pyrazole-amide-derived bis(pyridyl)ligand Supercapacitor Electrochemical sensor

Stereodivergent synthesis ofα-fluoroα-azaarylγ-butyrolactones via cooperative copper and iridium catalysis

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Fundamental Research 2024年第1期4卷 77-85页

作者： Kui Tian Xin Chang Lu Xiao xiu-Qin Dong chun-Jiang wang College of Chemistry and Molecular Sciences Engineering Research Center of Organosilicon Compounds&MaterialsMinistry of EducationWuhan UniversityWuhan 430072China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryShanghai 230021China Suzhou Institute of Wuhan University Suzhou 215123China

The development of stereodivergent synthetic methods to access all four stereoisomers of biologically importantα-fluoroγ-butyrolactones containing vicinal stereocenters is of great importance and poses a formidable challenge owing to ring strain and steric ***,a novel asymmetric[3+2]annulation ofα-fluoroα-azaaryl acetates with vinylethylene carbonate was successfully developed through Cu/Ir-catalyzed cascade allylic alkylation/lactonization,affording a variety of enantioenrichedα-fluoroγ-butyrolactones bearing vicinal stereogenic centers with high reaction efficiency and excellent levels of both stereoselectivity and regioselectivity(up to 98%yield,generally>20:1 dr and>99%ee).Notably,all four stereoisomers of these pharmaceutically valuable molecules could be accessed individually via simple permutations of two enantiomeric *** addition,other azaaryl acetates bearingα-methyl,α-chlorine orα-phenyl group were tolerated well in this *** mechanistic investigations were conducted to explore the process of this bimetallic catalysis based on the results of reaction intermediates,isotopic labelling experiments,and kinetic studies.

关键词： Asymmetric catalysis α-Fluoroγ-butyrolactones Synergistic catalysis Cascade reaction Stereodivergent synthesis

Using the modified Delphi method to research the influencing factors of longterm health-related quality of life in patients with unruptured intracranial aneurysms after endovascular treatment

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Chinese Neurosurgical Journal 2020年第2期6卷 70-75页

作者： Xiao-Dong Zhai chun-xiu wang Yong-Jie Ma Jia-Xing Yu Si-Shi Xiang Han-Yi Jiao Peng Shao Xin Guan Jun wang Hong-Qi Zhang Department of Neurosurgery Xuanwu HospitalCapital Medical UniversityNo.45 Changchun StreetXicheng DistrictBeijing 100053China China International Neuroscience Institute(China-INI) BeijingChina Department of Evidence-Based Medicine Xuanwu HospitalCapital Medical UniversityBeijingChina

Background:The purpose of this study was to use the modified Delphi method to identify the influencing factors of health-related quality of life(HRQoL)in patients with unruptured intracranial aneurysms(UIAs)after endovascular ***:A modified Delphi method to obtain expert consensus on the content of potential influencing factors of HRQoL in patients with UIAs treated by endovascular intervention was *** research team consists of three neuroradiologists and one epidemiologist from Xuanwu Hospital of Capital Medical *** randomly selected 21 well-known experts in cerebrovascular disease diagnosis and treatment as participating *** importance of the indicator is based on the 5-Likert *** standard deviation(SD),coefficient of variation(CV),mean(x),and minimum and maximum scores of each indicator were *** consistency was described by Kendall coefficient of concordance with a p value<0.05 indicating that the expert consistency was ***:Twenty-one and 18 questionnaires were responded in 2 rounds,with effective response rates of 85.7%and 100.0%,*** average authoritative coefficient(Cr)of all 21 experts was 0.88,familiarity with the indicators(Cs)was 0.82,and the judgment basis of the indicators(Ca)was ***,the x values of arterial puncture hematoma,hyperlipidemia,gender,marital status,and hospitalization for other diseases were lower than 3.5;CV for marital status and gender was higher than *** Kendall coefficient of concordance in the first round was 0.19(p<0.001),and the second round was 0.15(p<0.001).Conclusion:In this study,the factors affecting the recovery of HRQoL after endovascular treatment in patients with UIAs were analyzed by the modified Delphi method,which provided a valuable evidence for the clinical management and daily life guidance for UIAs patients.

关键词： Modified Delphi method Unruptured intracranial aneurysms Health-related quality of life

Pb induced dislocation defects of PtCo systems: Strain-triggered oxygen reduction reaction for PEMFC

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Nano Research 2024年第4期17卷 2462-2472页

作者： chun Jin Qiheng wang Jingjun Liu Beijing Key Laboratory of Electrochemical Process and Technology for Materials Beijing 100029China Beijing University of Chemical Technology Beijing 100029China

Design and development of advanced electrocatalysts with high performance and low Pt consumption are crucial for reducing the kinetic energy barrier of the cathode oxygen reduction reaction(ORR)and improving the efficiency of proton exchange membrane fuel cells(PEMFC).In this study,we demonstrate a Pb-modulated PtCo system for efficient ORR,in which the inclusion of Pb in ternary alloys induces dislocation defects due to the significant difference in atomic ***-PtCoPb was confirmed to exhibit significantly higher ORR activity and stability in acidic *** practical PEMFC applications,it outperforms the corresponding commercial Pt/C with a mass activity of 0.58 A·mgPt^(-1),making it a promising alternative to state-of-the-art Pt-based *** combination of experimental results and density functional theory(DFT)calculations offers valuable atomic-level insights into the dislocation *** with a larger atomic radius is located in the lattice stretching region below the dislocation slip plane,forming a structure similar to a Cottrell atmosphere,which reduces the dislocation energy and puts the system in a lower energy *** Cottrell atmosphere pins the dislocation structure and stabilizes the ternary *** adjusting the amount of added Pb,a moderate level of dislocation density induces a tuned strain effect,thereby enhancing the electrocatalytic mechanism by optimizing the electronic structure of the alloy surface and the adsorption and desorption of oxygen *** work provides valuable insights into the design and development of lattice dislocation defect structures to trigger strain effects for improving ORR performance.

关键词： dislocation defect strain effect Pb-modulated oxygen reduction reaction

Ore Geology,H-O-C Isotopes and 40Ar-39Ar Dating of the Wutonggou Iron Deposit,Eastern Tianshan,NW China:Implications for the Source,Timing,and Genesis of Hydrothermal Mineralization in a Sedimentary Iron Deposit

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Journal of Earth Science 2024年第4期35卷 1170-1185页

作者： chun-Long wang Yi-Tian wang State Key Laboratory of Geological Processes and Mineral Resources Collaborative Innovation Center for Exploration of Strategic Mineral ResourcesSchool of Earth ResourcesChina University of GeosciencesWuhan430074China MNR Key Laboratory of Metallogeny and Mineral Assessment Institute of Mineral ResourcesChinese Academy of Geological SciencesBeijing100037China

The Wutonggou iron deposit is located in the well-known iron metallogenic belt in the eastern Tianshan,NW China,and has been regarded as a sedimentary iron *** hydrothermal overprinting could play indispensable roles in the formation of high-grade iron ores in sedimentary iron deposits,previous studies mainly focused on sedimentary-related iron mineralization,while the nature and contribution of hydrothermal fluids are poorly ***,an integrated study of ore geology,H-O-C isotopes and^(40)Ar-^(39)Ar dating,is conducted on the Wutonggou deposit,in order to reveal the features,source,and timing of hydrothermal *** studied deposit includes two mining sections namely the Jianshan and ***δ^(18)O values of early magnetite from the Jianshan section range from+3.0‰to+5.8‰that nearly consistent with classic magmatic magnetite,while increase to 6.3‰-8.0‰in the late *** from the two sections shows comparable H-O isotopic compositions and identical fractionation trends,and is plotted in or periphery to the primary magmatic water *** from the two sections are broadly similar in carbon and oxygen isotopic compositions,and siderite from the Wutonggou section is plotted in the same ***,comparable stable isotopic compositions and evolution trends indicate similar magmatic fluids contributed hydrothermal iron mineralization in the two mining ***,water-rock interactions of varying degrees generated distinct mineralization styles in the Jianshan and Wutonggou sections,and caused the isotopic fractionation in late *** extracted from a hydrothermal siderite ore yielded a^(40)Ar-^(39)Ar plateau age of 299.5±2.0 Ma,indicates the timing of hydrothermal iron mineralization is corresponding to the emplacement of vicinity *** together,the hydrothermal mineralization in the Wutonggou iron deposit was the product of remobilization and upgrading of early sedimentary iron ores,a

关键词： iron deposits H-O-C isotopes 40Ar-39Ar dating sedimentary iron deposits Wutonggou iron deposit eastern Tianshan

A bifunctional POM-based Cu-viologen complex with mixed octamolybdate clusters for rapid oxidation desulfurization and effective photogeneration of hydrogen

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Rare Metals 2024年第1期43卷 236-246页

作者： Lin Yang Zhong Zhang Chao-Nan Zhang xiu-Li wang College of Chemistry and Materials Engineering Bohai UniversityJinzhou 121013China Professional Technology Innovation Center of Liaoning Province for Conversion Materials of Solar Cell Bohai UniversityJinzhou 121013China

The design and synthesis of catalysts for the oxidation desulfurization and production of hydrogen are extremely important for solving environmental pollution and energy ***,a novel bifunctional [α-Mo_(8)O_(26)]^(4-)/[β-Mo_(8)O_(26)]^(4-)-based Cu-viologen complex H_(4)[Cu_(2)~ⅠCl_(2)(Hbcbpy)_(4)] [α-Mo_(8)O_(26)] [β-Mo8O_(26)]·H_(2)O(BHU-2,Hbcbpy=1-(4-carboxybenzyl)-4,4'-bipyridinium) was synthesized and characterized by single-crystal X-ray diffraction(XRD),infrared radiation spectra,powder X-ray diffraction(PXRD) and X-ray photoelectron spectroscopy(XPS) *** structural characteristic of BHU-2 is the presence of two types of octamolybdate clusters [α-Mo_(8)O_(26)]^(4-)/[β-Mo_(8)O_(26)]^(4-)and a new binuclear Cu~Ⅰ-Hbcbpy complex linked by Cl-bridges[Cu_(2)ⅠCl_(2)(Hbcbpy)_(4)]^(4+).BHU-2 as a heterogeneous catalyst exhibits excellent activities to the oxidation desulfurization and photocatalytic hydrogen *** room temperature,BHU-2 can catalyze 96% conversion of methyl phenyl sulfide with 98% selectivity,and the process obeys the pseudo-first-order reaction kinetic with the half-life of9.6 *** notorious 2-chloroethyl ethyl sulfide can achieve 99% conversion with 98% selectivity within only1 min at the presence of BHU-2,and the turnover frequency(TOF) is up to 7400 h^(-1).BHU-2 also exhibits high catalytic activity for the oxidation of other aromatic and aliphatic thioethers within short time at room ***,BHU-2 shows a high catalytic activity for visible-light-driven hydrogen evolution with an H_(2) evolution rate of 1677.85 μmol·g^(-1)·h^(-1) within 10 ***,the catalytic activities do not decrease evidently after three cycles,revealing the prominent structural stability and recyclability.

关键词： Polyoxometalate Metal-organic complex Viologen Oxidation desulfurization Photocatalytic hydrogen production