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Suppressing the donor-like effect via fast extrusion engineering for high thermoelectric performance of polycrystalline Bi_(2)Te_(2.79)Se_(0.21)

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Journal of Materiomics 2023年第2期9卷 345-352页

作者： Xusheng liu Tong Xing Pengfei Qiu Tingting Deng Peng li xuewen li Xiaoya li Xun Shi State Key Lab of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai200050China Key Lab for light-weight Materials Nanjing Tech UniversityNanjing211816China

Bi2Te3-based alloys are the most mature commercial thermoelectric(TE)materials for the cooling application near room ***,the poor mechanical properties of the commercial zone melting(ZM)ingot severely limits the further ***,due to the donor-like effect,the robust polycrystalline n-type bulks usually have low TE performance near room ***,based on the commercial ZM ingots,a high figure of merit(zT)of 1.0 at 320 K and good mechanical properties are achieved via the hot *** dynamic recrystallization in the hot-extrusion process can suppress the donor-like effect and refine the large ZM grains into fine-equiaxed ***,the obtained polycrystalline Bi2Te2.79Se0.21 has good preferential orientation and high carrier mobility(m).The high m and the weaken donor-like effect maintain the high power factor(PF)of 43.1 mW cm^(-1)K^(-2)in the hot-extruded ZM *** to the enhanced phonon scattering,the total thermal conductivity ktot decreased to 1.35 W·m^(-1)·K^(-1).To demonstrate the good mechanical properties of the extruded ZM sample,micro TE dices with the cross sections of 300μm×300 mm and 200μm×200 mm are successfully cut from the extrusion *** study provided a fast and low-cost extrusion technique to improve the TE and mechanical properties of the commercial ZM ingot at room temperature.

关键词： Thermoelectric Bismuth telluride Donor-like effect Hot extrusion

Metal organic polymers with dual catalytic sites for oxygen reduction and oxygen evolution reactions

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Carbon Energy 2023年第5期5卷 127-137页

作者： Sijia liu Minghao liu xuewen li Shuai Yang Qiyang Miao Qing Xu Gaofeng Zeng CAS Key Laboratory of Low-Carbon Conversion Science and Engineering Shanghai Advanced Research Institute(SARI)Chinese Academy of Sciences(CAS)ShanghaiChina School of Physical Science and Technology ShanghaiTech UniversityShanghaiChina School of Chemical Engineering University of Chinese Academy of SciencesBeijingChina

Metal-organic frameworks and covalent organic frameworks have been widely employed in electrochemical catalysis owing to their designable skeletons,controllable porosities,and well-defined catalytic ***,the poor chemical stability and low electron conductivity limited their activity,and single-functional sites in these frameworks hindered them to show multifunctional roles in catalytic ***,we have constructed novel metal organic polymers(Co-HAT-CN and Ni-HAT-CN)with dual catalytic centers(metal-N_(4) and metal-N_(2))to catalyze oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).By using different metal centers,the catalytic activity and selectivity were *** them,Co-HAT-CN catalyzed the ORR in a 4e^(-)pathway,with a half-wave potential of 0.8 V versus RHE,while the Ni-HAT-CN catalyze ORR in a 2e^(-)pathway with H_(2)O_(2) selectivity over 90%.Moreover,the Co-HAT-CN delivered an overpotential of 350 mV at 10 mA cm^(-2) with a corresponding Tafel slope of 24 mV dec^(-1) for OER in a 1.0 M KOH aqueous *** experimental results revealed that the activities toward ORR were due to the M-N_(4) sites in the frameworks,and both M-N_(4) and M-N_(2) sites contributed to the *** work gives us a new platform to construct bifunctional catalysts.

关键词： covalent organic frameworks metal organic polymers oxygen evolution reaction oxygen reduction reaction single atom catalysts

Oxidation resistance of powder metallurgy Ti-45Al-10Nb alloy at high temperature

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International Journal of Minerals,Metallurgy and Materials 2022年第12期29卷 2232-2240页

作者： Xuchen Jin Peihao Ye Hongrui Ji Zhuanxia Suo Boxin Wei xuewen li Wenbin Fang School of Materials Science and Engineering Harbin University of Science and TechnologyHarbin 150040China The State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China

TiAl alloy with high Nb content,nominally Ti-45Al-10Nb,was prepared by powder metallurgy,and the oxidation resistance at 850,900,and 950℃was *** high-temperature oxidation-resistance mechanism and oxidation dynamics were discussed following the oxide skin morphology and microstructural evolution *** oxide skin structures were similar for 850 and 900℃,with TiO_(2)+Al_(2)O_(3)mixture covering TiO_(2)with dispersed Nb_(2)O_(5).At 950℃,the oxide skin was divided into four sublayers,from the outside to the parent metal:loose TiO_(2)+Al_(2)O_(3),dense Al_(2)O_(3),dense TiO_(2)+Nb_(2)O_(5),and TiO_(2)matrix with dispersed Nb_(2)O_(5).The Nb layer suppressed the outward diffusion of Ti atoms,hindering the growth of TiO_(2),and simultaneously promote the formation of a continuous Al_(2)O_(3)protective layer,providing the alloy with long-term high-temperature oxidation resistance.

关键词： Ti-45Al-10Nb elemental powder metallurgy microstructure high-temperature oxidation resistance

Effect of processing parameters on the microstructure and mechanical properties of TiAl/Ti_(2)AlNb laminated composites

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Journal of Materials Science & Technology 2022年第14期109卷 228-244页

作者： Donghai li Binbin Wang liangshun Luo xuewen li Yanjin Xu BinQiang li Diween Hawezy liang Wang Yanqing Su Jingjie Guo Hengzhi Fu National Key Laboratory for Precision Hot Processing of Metals School of Materials Science&EngineeringHarbin Institute of TechnologyHarbin 150001China Key Laboratory for lightweight Materials Nanjing Tech UniversityNanjing 211816China AVIC Manufacturing Technology Institute Beijing 100024China Materials Research Centre College of EngineeringSwansea UniversityBay CampusSwansea SA18ENUK

In order to improve the intrinsic brittleness of TiAl alloys,Ti_(2)AlNb alloys with outstanding ductility and toughness at room temperature,and good high-temperature performance are competitive candidates in constructing the TiAl-based laminated *** this work,TiAl/Ti_(2)AlNb laminated composites are successfully synthesized by vacuum hot pressing combined with the foil-foil(sheet)*** the pressure of 65 MPa,different holding time and temperature of hot pressing are tried and the optimized fabrication parameter is acquired as 1050℃/120 min/65 *** with the changes of processing parameters,the defect,microstructure,interface,phase transformation and the corresponding mechanical properties are detailly *** results show that the TiAl/Ti_(2)AlNb laminated composite fabricated at 1050℃ for 2 h achieves a good metallurgical interface *** corresponding interface microstructure is composed of region I and region *** region I consists of O,α_(2)and B2/βphase,and region II is made up ofα***,the tensile tests indicate that the composite synthesized at 1050℃ for 2 h possesses a maximum strength of 812 MPa and a total elongation of 1.31%at room temperature,and a strength of 539.71 MPa and the highest total elongation of 10.34%at 750℃.The well synergistic deformation ability between the interface and the two base alloys endows the composite an excellent tensile ***,the composite processed at 1050℃ for 2 h behaves the best fracture toughness in both arrester orientation and divider orientation with the value of 32.6 MPa.m^(1/2)and 30.1 MPa.m^(1/2),*** Ti_(2)AlNb alloy in the laminated structure effectively release the stress around the crack tip and plays a role in ***,crack deflection,crack bridging,crack blunting and fragmentation also make contributions to enhance the fracture toughness of the laminated composites.

关键词： TiAl/Ti_(2)AlNb laminated composite Hot pressing Processing parameters Microstructure Mechanical properties Fracture

Vacuum wetting of Ag/TA2 to develop a novel micron porous Ti with significant biocompatibility and antibacterial activity

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Journal of Materials Science & Technology 2022年第21期116卷 180-191页

作者： Guanpeng liu Yulong li Ming Yan Jicai Feng Jian Cao Min Lei Quanwen liu Xiaowu Hu Wenqin Wang xuewen li Key Lab for Robot and Welding Automation of Jiangxi Province Mechanical and Electrical Engineering SchoolNanchang UniversityNanchang 330031China Jiangxi Provincial Key Laboratory of Interdisciplinary Science Nanchang UniversityNanchang 330031China Department of Materials Science and Engineering and Shenzhen Key Laboratory for Additive Manufacturing of High-Performance Materials Southern University of Science and TechnologyShenzhen 518055China State Key Lab of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China The National Engineering Research Center for Bioengineering Drugs and the Technologies Institute of Translational MedicineNanchang UniversityNanchang 330031China The Engineering Training Center of Nanchang University Mechanical and Electrical Engineering SchoolNanchang UniversityNanchang 330031China

Porous Ti with low modulus,excellent bio-corrosion resistance,biocompatibility,and antibacterial activity is highly pursued as advanced implant *** this work,a new approach to prepare micron porous structures on the surface layer of a grade 2 commercially-pure Ti(TA2)was proposed,which utilized a simple vacuum wetting process of pure Ag on the surface of *** microstructure,corrosion resistance,biocompatibility,mechanical properties,antibacterial ability,and formation mechanism of the asfabricated porous Ti were *** results show that the pores(with average pore sizes of 0.5-5μm)are distributed on the surface layer of the TA2 with a depth of~10μ*** particular,a large number of silver nanoparticles(Ag NPs)form which are dispersed on the porous *** formation mechanisms of the porous structures and Ag NPs were elucidated,suggesting that the volatilization/sublimation of Ag in TA2 is *** porous Ti possesses excellent bio-corrosion resistance,surface wettability,biocompatibility,antibacterial activity,and a relatively low elastic modulus of 40-55 GPa,which may have a promising future in the field of orthopedic *** work also provides a novel idea for the development of advanced porous Ti materials for orthopedic-related basic research and biomedical applications.

关键词： Porous titanium Biomaterials Vacuum wetting Porous surface Antibacterial activity

Effects of the layer thickness ratio on the enhanced ductility of laminated aluminum

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Journal of Materials Science & Technology 2022年第16期111卷 256-267页

作者： Yiping Xia Hao Wu Kesong Miao xuewen li Chao Xu lin Geng Honglan Xie Guohua Fan School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China Key Laboratory for light-weight Materials Nanjing Tech UniversityNanjing 211816China Shanghai Synchrotron Radiation Facility Shanghai Institute of High Energy Applied PhysicsShanghai 200000China

The layered structural parameters have been reported to be critical for tuning the tensile properties of laminated ***,we investigated the effects of the thickness ratio(rc/f)of coarse-grained layers(CLs)to fine-grained layers(FLs)on the enhanced ductility of the laminated *** local strain evolution demonstrates that the strain delocalization ability of laminated Al is improved with the decrease of rc/*** interfacial strain gradients,which can produce extra work hardening,gradually approach and cover the CLs with the rc/fdecreasing,explaining the trend of uniform elongation in laminated Al with various rc/*** integrated fracture morphology characterization reveals that the increase of the rc/fleads to an improvement in the tolerance of the interfacial microcracks,which is corresponding to the variation of fracture elongation in the laminated ***,there is an evident transition of transverse propagation path of interfacial microcracks from the CLs to FLs with increasing the rc/*** on a geometrical criterion of microcracks connectivity,the preferential transverse propagation path of interfacial microcracks in these laminated Al was *** calculation based on this criterion also predicted the critical rc/fcorresponding to the optimal combination of strength and fracture *** work deepens the understanding of the role of structural parameters of laminated metals in achieving the strength and ductility synergy.

关键词： Layered structure Structural parameter Digital image correlation Crack propagation

Responses of Wheat Production, Quality, and Soil Profile Properties to Biochar Applied at Different Seasons in a Rice-Wheat Rotation

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Phyton-International Journal of Experimental Botany 2023年第12期92卷 3359-3370页

作者： lipei Chen Rilie Deng xuewen li Min Yu Hongdong Xiao Department of Horticulture Foshan UniversityFoshan528000China

In the rice-wheat rotation system,biochar(BC)can be applied at the initiation of the rice or wheat ***,we compared the effects of BC that were applied at two different crop seasons on wheat production,quality,and soil profile properties in a rice-wheat rotation system with nitrogen(N)fertilizer applied at 280 kg/ha *** showed that both wheat grain production and N recovery use efficiency were influenced by BC applied at two crop *** application did not affect the total non-essential amino-acid,but when applied during wheat season,BC significantly(pline(+48.2%),methionine(+43.8%),and isoleucine(+10.3%).We found that BC significantly(plication,however,the effect of BC on NO3–-N content varied with the application season and profile ***,BC applied at wheat and rice season significantly(plied during wheat season performed better in enhancing soil available phosphorus,potassium,and organic matter *** conclusion,we suggest that the optimum application time of BC for enhancing crop production and quality(take amino-acid content for example)and improving soil fertility is at the initiation of the wheat season.

关键词： Amino-acid biochar paddy soil rice-wheat rotation soil fertility soil organic matter

Laboratory and Semi-Field Evaluation on S-Methoprene Formulations Against Anopheles sinensis(Diptera:Culicidae)—Yuxi City,Yunnan Province,China

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China CDC weekly 2024年第6期6卷 105-108页

作者： Wenbo Hu Yijin Chen Ying liang Tianyun Su Qiyong liu xuewen li Xiaobo liu School of Public Health Cheeloo College of MedicineShandong UniversityJinan CityShandong ProvinceChina National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases WHO Collaborating Centre for Vector Surveillance and ManagementDepartment of Vector Biology and ControlNational Institute for Communicable Disease Control and PreventionChinese Center for Disease Control and PreventionBeijingChina EcoZone International Riverside CityCAUSA Department of Environment and Health School of Public HealthCheeloo College of MedicineShandong UniversityJinan CityShandong ProvinceChina Department of Vector Control School of Public HealthShandong UniversityJi’nan CityShandong ProvinceChina Xinjiang Key Laboratory of Vector-borne Infectious Diseases Urumqi CityXinjiang830002

Summary What is already known about this topic?Anopheles sinensis(***)is the predominant malaria vector in *** impact of S-methoprene on the emergence process of mosquito larvae suggests its potential as a control met... 详细信息

关键词： sinensis China. predominant

Biochar can Increase Chinese Cabbage(Brassica oleracea L.)Yield,Decrease Nitrogen and Phosphorus Leaching Losses in Intensive Vegetable Soil

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Phyton-International Journal of Experimental Botany 2022年第1期91卷 197-206页

作者： Haijun Sun Paramsothy Jeyakumar Hongdong Xiao xuewen li Jiayou liu Min Yu Prabal Bir Jung Rana Weiming Shi Co-Innovation Center for Sustainable Forestry in Southern China College of ForestryNanjing Forestry UniversityNanjing210037China Department of Horticulture College of Food Science and TechnologyFoshan UniversityFoshan528000China Environmental Sciences School of Agriculture and EnvironmentMassey UniversityPalmerston North4442New Zealand State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing210008China

There are few evidences on the effect of biochar on vegetable yield,nitrogen(N)and phosphorus(P)leaching losses under intensive vegetable production *** current field plot scale study evaluated responses of Chinese cabbage(Brassica oleracea L.)yield,N and P leaching losses using five N treatments of common N application rate according to local farmers’practice(N100%),reducing 20%or 40%N fertilizer(N80%and N60%),and reducing 40%N fertilizer but incorporating 10 or 20 t/ha biochar(N60%+BC10 and N60%+BC20).Results showed that N80%and N60%decreased both the cabbage economic and leaf yields by 6.8%-36.3%and 27.4%-37.7%,*** of biochar with reduced N fertilizer rates improved the cabbage yield,in particular the N60%+BC20 matched the yield that observed in N100%*** N and P uptake capacities of cabbage shoot probably contributed the higher vegetable production under both biochar amendment *** application mitigated the NH_(4)^(+)-N and total P leaching losses by 20%-30%and 29%-32%,respectively,compared with their counterpart treatment N60%.Nevertheless,biochar exerted no influence on the NO_(3)^(-)-N *** addition,soil organic matter content was recorded with 7.4%-28.7%higher following 10-20 t/ha biochar *** conclusion,biochar application can increase economic yield of cabbage via increasing N and P use efficiency,decrease N and P leaching losses,and improve soil quality in an intensive vegetable production system.

关键词： Biochar leachate non-point source pollution vegetable yield soil quality