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Biomimetic porous silicon oxycarbide ceramics with improved specific strength and efficient thermal insulation

Journal of Materials Science & Technology 2024年第1期168卷 185-193页

作者： Zhuoqing Zhang Jinghan Li lei cao Yu Shi Huajie Yang Rui Yang Fan Xie Xing Zhang Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China School of Materials Science and Engineering Shenyang Ligong UniversityShenyang 110159China Shenyang Aircraft Design and Research Institute Shenyang 110035China

Considering the challenge of aerodynamic heating,the development of high-performance insulating ce-ramic materials with lightweight and low thermal conductivity is crucially important for aerospace vehi-cles to achieve flight at high speed for a long *** this work,macro-porous silicon oxycarbide(SiOC)ceramics with directional pores(DP-SiOC)(mean pore size of 88.1μm)were prepared using polysiloxane precursors via freeze casting and photocrosslinking,followed by *** DP-SiOC samples were lightweight(density∼0.135 g cm^(-3))with a porosity of 90.4%,which showed good shapability through the molding of polysiloxane *** DP-SiOC samples also exhibited an ultra-low thermal con-ductivity of 0.048 W(m K)^(-1)at room temperature,which can also withstand heat treatment at 1200°C for 1 *** addition,scaffolds with triply periodic minimal surfaces(TPMS)were fabricated using digital light processing(DLP)printing,which was further filled with polysiloxane precursors for increasing the strength of *** TPMS scaffolds filled with macro-porous SiOC ceramics(TPMS-DP-SiOC)showed good integration between TPMS and macro-pore structures,which had a porosity∼75%and high specific strength of 9.73×10^(3)N m kg^(-1).The thermal conductivity of TPMS-DP-SiOC samples was 0.255 W(m K)^(-1)at room *** biomimetic TPMS-DP-SiOC ceramics developed in this study are likely used for thermal protection systems.

关键词： Thermal insulation Light weight Macro-porous ceramics SiOC

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Migration routes,population status and important sites used by the globally threatened Black-faced Spoonbill(Platalea minor):a synthesis of surveys and tracking studies

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Avian Research 2021年第4期12卷 425-441页

作者： Yiwen Chen Yat-tung Yu Fanjuan Meng Xueqin Deng lei cao Anthony David Fox School of Life Sciences University of Science and Technology of ChinaHefei 230026China State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of Sci-encesBeijing 100085China Hong Kong Bird Watching Society Hong Kong SARChina University of Chinese Academy of Sciences Beijing 100049China Department of Bioscience Aarhus UniversityKaløGrenåvej 148410 RøndeDenmark.

Background:The Black-faced Spoonbill(Platalea minor)is a globally threatened species,nesting mainly in western Korea with smaller numbers breeding in Liaoning Province,China,and Far East *** winter field surveys to estimate the species'population size were almost totally conducted in coastal areas,but tracking studies showed that some individuals now winter *** ensure its long-term survival,we need a more comprehensive assessment of the current distribution and abundance of the ***:We combined the most recent count data and satellite tracking information to update existing informa-tion about the population abundance and distribution of the Black-faced Spoonbill at all stages of its annual life cycle,and how these have changed during ***:Black-faced Spoonbills mainly breed on the west coast of the Korean peninsula,while immature birds show a wider summer distribution throughout Yellow Sea coastal areas,when a few remain on wintering sites in the *** tracking results and mid-winter counts confirmed known wintering sites on the east and south coasts of China,but showed that the species also winters on wetlands in the Yangtze River floodplain and in Southeast *** 2004-2020,counts of wintering birds in coastal habitats increased from 1198 to 4864,with numbers wintering on the island of Taiwan contributing most to the overall *** counts found 5222 in *** also identify key wintering and stopover sites as well as their current conservation ***:This study revised the known summering and wintering ranges of the Black-faced Spoonbill and assessed the conservation status of key sites based on a combination of field survey and satellite tracking *** recommend prioritisation of further field research to identify and survey inland wintering areas in the Yangtze River floodplain and summering areas of immature *** tracking of adult individuals and birds during spring migration is

关键词： Black-faced Spoonbill Breeding distribution Coastal mudflats Conservation status Platalea minor Population abundance Winter distribution Yangtze River floodplain

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Functional recovery of injured sciatic nerve by intraperitoneal injection of multiwalled carbon nanotubes

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Neural Regeneration Research 2011年第7期6卷 505-509页

作者： Qigang Yang Qiong Zhang Yongping Chen lei cao Wei Jiang Guihai Chen Department of Neurology the First Affiliated Hospital of Anhui Medical University Hefei 230022 Anhui Province China Department of Biomedical Engineering Johns Hopkins University Baltimore MD 212053 USA

Some evidence suggests that multiwalled carbon nanotubes can promote neuronal differentiation and growth. The present study investigated the effect of functional multiwalled carbon nanotubes （MWCNTs） on functional recovery of injured sciatic nerves in mice. The results revealed that MWCNTs accelerated the recovery of functional index scores of injured sciatic nerves in mice. Moreover, the medullary sheath was significantly thicker in the injured sciatic nerve following MWCNTs administration. These effects were dose-dependent.

关键词： carbon nanotubes sciatic nerve functional recovery neural regeneration

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Magnetic Hardening of Rapidly Quenched Co-M-Zr(M=B,Fe)Alloys

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Chinese Physics Letters 1993年第3期10卷 175-178页

作者： SHEN Baogen YANG Linyuan cao lei GUO Huiqun State Key Laboratory of Magnetism Institute of PhysicsAcademia SinicaBeijing 100080

Effects of the quenching rate and annealing temperature on hard magnetic properties of rapidly quenched Co_(84-x)B_(x)Zr_(16)and Co_(82-x)Fe_(x)Zr_(18)alloys were *** B-or Fe-content dependence of room temperature coercivity H_(c),remanence B_(r) and maximum energy product(BH)_(max) are *** H_(c) is suggested to originate from the microstructure with the optimal grain size.

关键词： microstructure grain alloys

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Conceptual design and heat transfer performance of a flat-tile water-cooled divertor target

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Plasma Science and Technology 2021年第9期23卷 194-205页

作者： lei LI Le HAN Pengfei ZI lei cao Tiejun XU Nanyu MOU Zhaoliang WANG lei YIN Damao YAO Institute of Plasma Physics Chinese Academy of SciencesHefei 230031People's Republic of China

The divertor target components for the Chinese fusion engineering test reactor(CFETR)and the future experimental advanced superconducting tokamak(EAST)need to remove a heat flux of up to20 MW *** view of such a high heat flux removal requirement,this study proposes a conceptual design for a flat-tile divertor target based on explosive welding and brazing *** water-cooled channels with a special thermal transfer structure(TTS)are designed in the heat sink to improve the flat-tile divertor target’s heat transfer performance(HTP).The parametric design and optimization methods are applied to study the influence of the TTS variation parameters,including height(H),width(W*),thickness(T),and spacing(L),on the *** research results show that the flat-tile divertor target’s HTP is sensitive to the TTS parameter changes,and the sensitivity is T>L>W*>*** HTP first increases and then decreases with the increase of T,L,and W*and gradually increases with the increase of *** optimal design parameters are as follows:H=5.5 mm,W*=25.8 mm,T=2.2 mm,and L=9.7 *** HTP of the optimized flat-tile divertor target at different flow speeds and tungsten tile thicknesses is studied using the numerical simulation method.A flat-tile divertor mock-up is developed according to the optimized *** addition,high heat flux(HHF)tests are performed on an electron beam facility to further investigate the mock-up *** numerical simulation calculation results show that the optimized flat-tile divertor target has great potential for handling the steady-state heat load of 20 MW m-2under the tungsten tile thickness<5 mm and the flow speed7 m s^(-1).The heat transfer efficiency of the flat-tile divertor target with rectangular cooling channels improves by13%and30%compared to that of the flat-tile divertor target with circular cooling channels and the ITER-like monoblock,*** HHF tests indicate that the flat-tile divertor mock-up can successfully withstand

关键词： CFETR heat transfer performance parametric design and optimization HHF tests flat-tile divertor target

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Plasma spray of biofunctional(Mg, Sr)-substituted hydroxyapatite coatings for titanium alloy implants

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Journal of Materials Science & Technology 2019年第5期35卷 719-726页

作者： lei cao Ihsan Ullah Na Li Shiyu Niu Rujie Sun Dandan Xia Rui Yang Xing Zhang Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China University of the Chinese Academy of Sciences Shijingshan District Beijing 100049 China School of Materials Science and Engineering University of Science and Technology of China. Hefei 239056 China Shenyang Pharmaceutical University Shenyang 110016 China University of Utah Salt Lake City UT 84112 USA

Plasma-sprayed hydroxyapatite (HA) coatings have been widely utilized in load-bearing titanium alloy implants. In this study, Mg, Sr co-substituted HA ((Mg,Sr)-HA) nano-scale powders have been synthesized, which are further used to prepare (Mg,Sr)-HA coatings on Ti-6A1-4V alloys in order to improve the biological functions. The average size of (Mg,Sr)-HA nano particles is ~75nm. The average bonding strength for (Mg,Sr)-HA coating and samples after heat treatment at 500℃ or 600℃ for 3h are 26.17±2.11 MPa, 36.07±4.48 MPa and 37.07 ±2.95 MPa, respectively. There is a significantly increase of bonding strength likely due to low residual stress after heated ***3T3-E1 cells show a high proliferation rate when cultured with (Mg,Sr)-HA coating extract compared to the normal culture medium, which also exhibit large extension and depositi on of extracellular matrices when adhered on the coating surfaces. Thus, these (Mg,Sr)-HA coatings show high bonding strength and improved biological functions, which offer promising future applications in the fields of orthopedics and dentistry.

关键词： Plasma spray Hydroxyapatite Titanium alloys Biological functions Bon ding strength

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Synthesis and characterization of high entropy(TiVNbTaM)_(2)AlC(M=Zr,Hf)ceramics

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Journal of Advanced Ceramics 2024年第2期13卷 237-246页

作者： lei cao Qiqiang Zhang Lijing Du Shuai Fu Detian Wan Yiwang Bao Qingguo Feng Chunfeng Hu Key Laboratory of Advanced Technologies of Materials Ministry of EducationSchool of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China State Key Laboratory of Green Building Materials China Building Materials AcademyBeijing 100024China

The high-entropy design of MAX phases is expected to confer superior properties,but its study was hindered by the complex synthesis method and limited purity of *** this work,two noteworthy types of high-entropy MAX phase structural ceramics,high-entropy(TiVNbTaM)_(2)AlC(M=Zr,Hf),were designed and prepared by the in-situ synthesis using spark plasma sintering(SPS).The microstructure and lattice parameters of sintered samples were *** with the single-component MAX phases,the highly pure high-entropy(TiVNbTaZr)_(2)AlC sample had good physical and mechanical properties,including electrical conductivity of 0.96×106Ω^(-1)·m^(-1),thermal expansion coefficient of 3.65×10^(-6) K^(-1),thermal conductivity of 8.98 W·m^(-1)·K^(-1),Vickers hardness of 9.80 GPa,flexural strength of 507 MPa,fracture toughness of 5.62 MPa·m^(1/2),and compressive strength of 1364 MPa,which exhibited the remarkable hardening-strengthening effect.

关键词： MAX phase high-entropy ceramic microstructure physical properties mechanical properties

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Dielectric properties of Simon poplar wood flour/polypropylene composite at oven-dry state

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Forestry Studies in China 2008年第4期10卷 265-269页

作者： WANG lei cao Jin-zhen WANG Yi College of Materials Science and Technology Beijing Forestry University Beijing 100083 E R. China

Interfacial compatibility is a crucial factor to the performance of wood-plastic composites （WPCs）. Yet, so far, the coupling mechanisms of WPC have not been completely understood. In order to further clarify the interfacial coupling mechanism, the dielectric constant and dielectric loss factor of Simon poplar wood flour/polypropylene composites without additives at different wood contents were measured at oven-dry state, and parameters and thermodynamic quantities of the relaxation process were also analyzed and calculated. Consequently, an obvious relaxation process based on the reorientation of methanol groups in amorphous region of wood cell wall was observed exactly that its dielectric loss factor peak decreased with the decreasing wood content within the measured range of 50%-100%. With the trend of dielectric relaxation strength, the two changing trends both revealed that the existence of polypropylene could hinder reorientation of methanol groups. Following the decreasing wood contents, the effect of the hindrance on the dielectric properties turned obvious gradually. It elucidated that introduction of polypropylene caused the quantities of hydrogen bonds formed between each methanol group and the groups around it change. The same conclusion could be drawn from the analysis of thermodynamic quantities during the dielectric relaxation progress.

关键词： Simon poplar wood flour/polypropylene composite wood content dielectric relaxation methanol group

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Annual migratory patterns of Far East Greylag Geese(Anser anser rubrirostris)revealed by GPS tracking

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Integrative Zoology 2020年第3期15卷 213-223页

作者： Xianghuang LI Xin WANG lei FANG Nyambayar BATBAYAR Tseveenmyadag NATSAGDORJ Batmunkh DAVAASUREN Iderbat DAMBA Zhenggang XU lei cao Anthony David FOX State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijingChina University of Chinese Academy of Sciences BeijingChina School of Life Science University of Science and Technology of ChinaHefeiAnhuiChina Wildlife Science and Conservation Center of Mongolia UlaanbaatarMongolia Key Laboratory of Forestry Remote Sensing Based Big Data&Ecological Security for Hunan Province Central South University of Forestry and TechnologyChangshaChina Department of Bioscience Aarhus UniversityRøndeDenmark

Twenty Far East Greylag Geese,Anser anser rubrirostris,were captured and fitted with Global Positioning System/Global System for Mobile Communications(GPS/GSM)loggers to identify breeding and wintering areas,migration routes and stopover *** data for the first time showed linkages between their Yangtze River wintering areas,stopover sites in northeastern China,and breeding/molting grounds in eastern Mongolia and northeast China.10 of the 20 tagged individuals provided sufficient *** stopped on migration at the Yellow River Estuary,Beidagang Reservoir and Xar Moron River,confirming these areas as being important stopover sites for this *** median spring migration duration was 33.7 days(individuals started migrating between 25 February and 16 March and completed migrating from 1 to 9 April)compared to 52.7 days in autumn(26 September-13 October until 4 November-11 December).The median stopover duration was 31.1 and 51.3 days and the median speed of travel was 62.6 and 47.9 km/day for spring and autumn migration,re*** significant differences between spring and autumn migration on the migration duration,the stopover duration and the migration speed confirmed that tagged adult Greylag Geese traveled faster in spring than autumn,supporting the hypothesis that they should be more time-limited during spring migration.

关键词： Anser anser autumn migration greylag goose GPS/GSM loggers spring migration

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Boron Group Ions Direct Conversion of Carbon and Methane into Ethylene in DFT Study

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Chinese Journal of Structural Chemistry 2020年第2期39卷 255-262,185页

作者： HOU Xiu-Fang BAI Chuan cao Ya-lei FU Feng Laboratory of Analytical Technology and Detection College of Chemistry and Chemical EngineeringYan'an UniversityYan'an 716000China Qiushi Honors College Tianjin UniversityTianjin 300350China

In this study, density functional theory calculations reveal how boron group ions M^+(M = B, Al, Ga, In, and Tl) directly convert carbon and methane into ethylene at room temperature. M^+ reacts with the carbon atom to form the cation MC^+. Then, the reaction of MC^+ with methane leads to the cleavage of metal-carbon bond and the formation of CH2CH2 through C-C coupling, with the ion M^+ serving as a leaving group. The cycle then begins again. The mechanism of C/CH4 system catalyzed by five ion types is investigated herein, and the reasons for the different reactivity of five ion types are determined. The moderate strength of the Al^+-C bond results in Al^+ being the only appropriate catalyst of M^+(M?=?B, Al, Ga, In, and Tl) that can catalyze methane and carbon into ethylene.

关键词： boron group ion C–C coupling DFT ethylene

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