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Ore-forming Fluid and Metallogenic Mechanism of Wolframite-Quartz Vein-type Tungsten Deposits in South China

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Acta Geologica Sinica(English Edition) 2020年第6期94卷 1774-1796页

作者： NI Pei li wensheng PAN Junyi State Key Laboratory for Mineral Deposits Research Institute of Geo-FluidsSchool of Earth Sciences and EngineeringNanjing UniversityNanjing 210023China

South China is endowed with copious wolframite-quartz vein-type W deposits that provide a significant contribution to the world‘s tungsten *** is spatially associated with highly evolved granites,which have been interpreted as products of ancient crustal *** veins are mainly hosted in low-grade metamorphosed quartz sandstone,slate and granitic *** ore minerals mainly comprise wolframite,cassiterite,scheelite and pyrite,with minor molybdenite,arsenopyrite and *** steeply dipping veins can be divided into five zones from top to the bottom,namely:(Ⅰ)thread,(Ⅱ)veinlet,(Ⅲ)moderate vein,(Ⅳ)thick vein,and(Ⅴ)thin out *** general,three types of fluid inclusions at room temperature are commonly recognized in wolframite and/or quartz from these veins:two-phase liquid-rich(type L),two-phase CO2-bearing(type CB),and CO2-rich(type C).Comparative microthermometry performed on fluid inclusions hosted in wolframite and associated quartz indicates that most wolframite was not coprecipitated with the coexisting *** petrographic observation and cathodoluminescence(CL)imaging on coexisting wolframite and quartz of the Yaogangxian deposit,show repeated precipitation of quartz,wolframite,and muscovite,suggesting a more complex fluid process forming these *** studies of H-O isotopes and fluid inclusions suggested that the main ore-forming fluids forming the wolframite-quartz vein-type deposits had a magmatic source,whereas an unresolved debate is centered on whether mantle material supplemented the ore-forming *** variable CO2 contents in the ore-forming fluids also implies that CO2 might have had a positive effect on ore *** inclusion studies indicate that wolframite was most likely deposited during cooling from an initial H2 O+Na Cl±CO2 magmatic *** addition,fluid-phase separation and/or mixing with sedimentary fluid might also have played an important role in promoting wolframite de

关键词： metallogeny wolframite-quartz vein fluid inclusions microthermometry Nanling region

Synthesis of dimethyl ether from methane mediated by HBr

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Journal of Natural Gas Chemistry 2009年第3期18卷 306-311页

作者： Qin You Zhen liu wensheng li Xiaoping Zhou Department of Chemical Engineering Hunan University Changsha 410082 Hunan China College of life Science and Pharmaceutical Engineering Nanjing University of Technology Nanjing 210009 Jiangsu China

Dimethyl ether （DME） was synthesized from methane through a two-step process, in which CH3Br was prepared from the oxidative bromination reaction of methane in the presence of HBr and oxygen over a Rh-SiO2 catalyst and then, in the second step, CH3Br was hydrolyzed to DME over a silica supported metal chloride catalyst. 12 mol%ZnCl2/SiO2 catalyst was found to be the most active, but it deactivated because of Cl- losing.

关键词： din]ethyl ether methane oxidative bromination methyl bromide catalyst

Facile modification of aluminum hypophosphate and its flame retardancy for polystyrene

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Chinese Journal of Chemical Engineering 2023年第8期60卷 90-98页

作者： wensheng li liangyuan Qi Daolin Ye Wei Cai Weiyi Xing State Key Laboratory of Fire Science University of Science and Technology of ChinaHefei 230026China Nano Science and Technology Institute University of Science and Technology of ChinaSuzhou 215123China Suzhou Key Laboratory of Urban Public Safety Suzhou Institute for Advanced StudyUniversity of Science and Technology of ChinaSuzhou 215000China

A phosphorus-containing flame retardant, aluminum hypophosphite(AHPi), has been modified by(3-aminopropyl) triethoxysilane(KH550) to prepare flame-retardant polystyrene(PS). The influence of modified AHPi on the morphology and characterization was investigated, and differences in flame retardant properties of the PS/AHPi and PS/modified AHPi were compared. The PS composite can pass the vertical burning tests(UL-94 standard) with a V-0 rating when the mass content of modified AHPi reaches20%, compared with the mass content of 25% AHPi. The element mapping of the PS composite shows that modified AHPi has better dispersion in PS than AHPi. Thermogravimetric analysis results indicated that adding modified AHPi can advance the initial decomposition temperature of the composite *** the addition of modified AHPi, the decrease in peak heat release rate(p HRR) is more evident than AHPi, and the char yield of the resultant PS composites gradually increased. With the addition of 25%modified AHPi, the p HRR and total heat release of PS composites decreased by 81.4% and 37.6%. The modification of AHPi promoted its dispersion in the PS matrix and improved the char formation of PS composites. The results of real-time infrared spectrometry of PS composites, Fourier transform infrared spectra and X-ray photoelectron analysis of the char layer indicated that modified AHPi has flame retardancy in condensed and gas phases.

关键词： Nanomaterials Safety Thermodynamic properties Aluminum hypophosphite Char formation mechanism

One-step separation and recovery of rare earth and iron from NdFeB slurry via phosphoric acid leaching

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Journal of Rare Earths 2022年第2期40卷 338-344,I0006页

作者： ling He Qipeng Xu wensheng li Qizheng Dong Weimin Sun State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of TechnologyLanzhou 730050China School of Materials Science and Engineering Lanzhou University of TechnologyLanzhou 730050China

The recovery of rare earth elements(REEs)from NdFeB slurry by traditional hydrometallurgy has been limited becuase a large number of REEs are lost during separation together with *** this paper,a simple and sustainable method is proposed to efficiently separate and recover REEs and iron from NdFeB *** were recovered by one-step selective precipitation in phosphoric acid,and the dissolved iron was recovered by oxalic *** acid leaching results show that under the conditions of 4 mol/L phosphoric acid,80℃,L/S of 30:1 and 90 min,the leaching efficiencies of Fe and REEs reach 98.76%and1.09%,*** the rest of REEs remained in the leaching residue in the form of REEPO_(4)·nH_(2)O *** mixed rare earth oxide(rare earth oxalate roasted at 800℃)and FeC_(2)O_(4)·2 H_(2)O are obtained by oxalic acid precipitation with purities of 99.49%and 97.17%from the REEPO4·nH_(2)O dissolving solution and the phosphoric acid leaching ***,the phosphoric acid is regenerated while recovering iron,and it can be reused in the phosphoric acid leaching step after removing the impurity C_(2)O_(4)^(2-).In summary,this work provides an efficient and environmentally friendly method for recovering REEs and iron from NdFeB slurry waste.

关键词： NdFeB slurry Phosphoric acid leaching Iron Rare earth elements Oxalic acid

A response to numerical benchmark for solidification of binary alloys: macro-segregation with thermo-solutal convection

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China Foundry 2012年第2期9卷 171-177页

作者： li wensheng Shen Houfa liu Baicheng Key Laboratory for Advanced Materials Processing Technology Ministry of EducationDepartment of Mechanical EngineeringTsinghua University Beijing 100084China

As a necessary step toward the quantitative predictions of macro-segregation commonly found in metal castings, classical experiments and numerical benchmarks have been used to validate a simplified binary- alloy solidification model. The model consists of fully coupled conservation equations for the transport phenomena （heat transfer, solute redistribution, ~tnd melt convection） that lead to macro-segregation in a solidifying ingot with a fixed solid phase. Simulations were performed for solidification of either a Pb-48wt.%Sn or a Sn-5wt.%Pb alloy in a rectangular cavity. The present predictions were compared with experimental data and numerical reference results reported in the literature. Subsequently, the model was applied to a numerical benchmark problem described in the literature for solidification of a Sn-10wt.%Pb alloy. Simulation results for flow velocity, liquid fraction evolution, and macro-segregation maps also were compared with literature predictions, showing similar trends. It is concluded that additional comparisons to experimental results are still required to assess more complex solidification models.

关键词： benchmark solidification macro-segregation thermo-solutal convection

Characterizations and mechanical properties of impregnated diamond segment using Cu-Fe-Co metal matrix

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Rare Metals 2012年第1期31卷 81-87页

作者： li, wensheng Zhang, Jie Wang, Shucai Dong, Hongfeng li, Yaming liu, Yi State Key Laboratory of AdvancedNon-Ferrous Materials Lanzhou University of Technology Lanzhou 730050 China National Center for Advanced Tribology School of Engineering Sciences University of Southampton Southampton SO171BJ UK

Diamond impregnated Cu-Fe-Co based saw-blade segments are directly processed by vacuum and pressure-assisted sintering at different temperature,with the purpose of reducing the cobalt content in diamond *** and iron are used as the bonding elements and co-balt-chrome pre-alloyed powder is used as the hardening *** of sintering temperature on microstructures and mechanical properties of the sintered matrix and diamond graphitization were investigated by X-ray diffraction analysis,electron probe micro-analyzer,universal testing machine,digital Rockwell hardness tester and Raman scattering *** showed that microstructures of the sintered matrix were refined and porosities in the sintered matrix were closed to a more spherical-like shape with the increase of the sintering ***,hardness and tensile strength of the matrix sintered at 820 ℃ were 12.75%,2.72% and 156.38% higher than that of the matrix sintered at 740 ℃,*** graphitization was not occurred at 820 ℃.The hardness and the tensile strength rose 32.8% and 13.5%,respectively,after 7.5 h ageing *** matrix densification ascent and the dispersed distribution of Co-Cr pre-alloyed powders contributed a hardness improvement and a tensile strength improvement to the Cu-Fe based matrix.

关键词： Cu-Fe-Co based matrix sintering temperature graphitization microstructure mechanical properties

A measurable evaluation method of visual comfort in underground space by intelligent sorting and classification algorithms

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Underground Space 2022年第3期7卷 453-464页

作者： Biao Zhou Yingbin Gui Xiongyao Xie wensheng li Qing li Key Laboratory of Geotechnical and Underground Engineering Tongji UniversityShanghaiChina Department of Geotechnical Engineering Tongji UniversityShanghaiChina China Railway Siyuan Survey and Design Group WuhanChina

Based on human perception and machine learning methods,this study proposes a measurable method for evaluating visual comfort in underground ***,a comfort evaluation index based on the characteristics of human visual perception is proposed,and color features and segmentation extraction methods for intelligent methods are ***,using probability statistics and machine learning methods,a multi-class intelligent sorting and classification algorithm for ranking visual comfort levels is constructed and a comparison is made of the suitability of different intelligent methods for evaluating visual *** random forest algorithm is then selected as the most effective measurable intelligent evaluation algorithm for underground ***,the proposed method is compared to intelligent methods employed by previous research,and a case study,the Wujiaochang underground space in Shanghai,China,is applied as the *** show that the proposed method can effectively improve the quantification and refinement of human perception and evaluation of comfort in underground spaces;this method will also be useful in computer-aided generative design in the future.

关键词： Underground space Visual comfort Measurable evaluation Machine learning

Influence of reduction energy match among CuO species in CuO-CeO_2 catalysts on the catalytic performance for CO preferential oxidation in excess hydrogen

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Journal of Natural Gas Chemistry 2011年第2期20卷 111-116页

作者： Zhigang liu Yunlong Xie wensheng li Renxian Zhou Xiaoming Zheng School of Chemistry and Chemical Engineering Hunan University Changsha 410082 Hunan China Institute of Catalysis Zhejiang University Hangzhou 310028 Zhejiang China Institute of Physical Chemical Zhejiang Normal University Jinhua 321004 Zhejiang China

In the present study, we have investigated the reducibility of CuO species on CuO-CeO2 catalysts and the influence of CuO species on the catalytic performance for CO preferential oxidation （CO PROX） in excess hydrogen. It is revealed that the smaller the difference of reduction temperature （denoted as ？T） for two adjacent CuO species is, the higher the catalytic activity of CuO-CeO2 for the PROX in excess hydrogen may be obtained. It means that if the reduction energy of Cu0-Cu2＋ pairs matched better, the reduction-oxidation recycle of Cu0-Cu2＋ pairs would go on more easily, then the transferring energy of Cu0-Cu2＋ pairs would be lesser. Therefore, the CuO-CeO2 catalysts will be largely improved in their catalytic performance if the different CuO species on the catalysts have matched the reduction energy, which would allows them to cooperate effectively.

关键词： energy match cooperative effect CuO-CeO2 preferential oxidation CO

Effect of Cu addition on the microstructure and tribological performance of Ni60 directional structure coating

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International Journal of Minerals,Metallurgy and Materials 2023年第4期30卷 715-723页

作者： Xiaotian Yang Xinhua Wang Jun Zhou Hengli Wei Rong Zeng wensheng li School of Materials Science and Engineering Lanzhou University of TechnologyLanzhou 730050China State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of TechnologyLanzhou 730050China Wenzhou Engineering Institute of Pump&Valve Lanzhou University of TechnologyWenzhou 325105China

The Ni60/15wt% Cu directional structure coating was prepared by the composite technology of flame spraying, induction remelting,and forced cooling, and the effect of Cu on the microstructure, phase, hardness, and wear performance of Ni60 coatings was investigated. Results showed that Cu addition makes the microstructure of Ni60 directional structure coating more compact, and Cu is mainly enriched within the crystal grain, resulting in the formation of Cu_(3.8)Ni as the bonding phase. Compared with Ni60 directional structure coating, Ni60/Cu directional structure coating has a lower hardness, lower friction coefficient, and lower wear rate, which indicate that Cu can effectively enhance the antifriction performance of Ni60 directional structure coating.

关键词： induction remelting directional structure coating microstructure tribological performance