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锆富氢新材料中发现高于70 K的高温超导性质

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Science Bulletin 2022年第9期67卷 907-909,M0003页

作者： Changling Zhang Xin He Zhiwen Li Sijia Zhang Shaomin Feng xiancheng Wang Richeng yu Changqing Jin Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China

氢是周期表里质量最轻的元素,早期理论预测氢在超高压条件可以呈现固体金属态,根据BCS电声耦合理论推测金属氢可能具有高温超导特性.然而实现纯氢的金属化需要很高的压力,技术复杂极具挑战.富氢化合物可以对氢提供“化学预压缩”,有可... 详细信息

氢是周期表里质量最轻的元素,早期理论预测氢在超高压条件可以呈现固体金属态,根据BCS电声耦合理论推测金属氢可能具有高温超导特性.然而实现纯氢的金属化需要很高的压力,技术复杂极具挑战.富氢化合物可以对氢提供“化学预压缩”,有可能在较低压力实现以氢为主的金属化和超导,目前实验上已经在硫、稀土和碱土金属等富氢化物材料发现高温超导现象.本文作者运用自行研发的先进的超高压和激光加热一体化的极端条件集成技术,在~220 GPa、2000 K的高压高温条件下成功合成了高质量的锆富氢新化合物,并在锆富氢化合物中发现高压在位诱导的临界转变温度(T;)高达71 K的超导现象,这是首次在4d过渡金属氢化物发现高温超导.

关键词：高温超导超导现象高压高温激光加热金属化临界转变温度极端条件金属氢

A numerical model for bird strike on sidewall structure of an aircraft nose

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Chinese Journal of Aeronautics 2014年第3期27卷 542-549页

作者： Liu Jun Li yulong Gao Xiaosheng yu xiancheng School of Aeronautics Northwestern Polytechnical University Department of Mechanical Engineering The University of Akron

In order to examine the potential of using the coupled smooth particles hydrodynamic （SPH） and finite element （FE） method to predict the dynamic responses of aircraft structures in bird strike events, bird-strike tests on the sidewall structure of an aircraft nose are carried out and numerically simulated. The bird is modeled with SPH and described by the Murnaghan equation of state, while the structure is modeled with finite elements. A coupled SPH-FE method is developed to simulate the bird-strike tests and a numerical model is established using a commercial software PAM-CRASH. The bird model shows no signs of instability and correctly modeled the break-up of the bird into particles. Finally the dynamic response such as strains in the skin is simulated and compared with test results, and the simulated deformation and fracture process of the sidewall structure is compared with images recorded by a high speed camera. Good agreement between the simulation results and test data indicates that the coupled SPH-FE method can provide a very powerful tool in predicting the dynamic responses of aircraft structures in events of bird strike.

关键词： Bird strike Experiment Sidewall structure Simulation Smooth particles hydrodynamic （SPH） method

Precipitation and heterogeneous strengthened CoCrNi-based medium entropy alloy with excellent strength-ductility combination from room to cryogenic temperatures

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Science China(Technological Sciences) 2022年第8期65卷 1780-1797页

作者： XIE yu ZHAO PengCheng TONG YongGang TAN JianPing SUN BinHan CUI Yan WANG RunZi ZHANG xiancheng TU ShanTung Key Laboratory of Pressure Systems and Safety Ministry of EducationSchool of Mechanical and Power EngineeringEast China University of Science and TechnologyShanghai 200237China College of Automobile and Mechanical Engineering Changsha University of Science and TechnologyChangsha 410114China Key Laboratory for Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center Institute of Fine ChemicalsSchool of Chemistry&Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China

The improved understandings of the mechanical properties as well as deformation mechanisms at cryogenic temperatures are the prerequisite for realizing the application of any new engineering materials to cryogenic industries.Here,a(CoCrNi)_(94)Al_(3)Ti_(3) medium entropy alloy(MEA)with nanoscale L12 coherent precipitates and heterogeneous grain structures was prepared by codoping Al and Ti elements with subsequent cold rolling and heat treatment processes.The mechanical properties were evaluated at the temperature range of 293–113 K.The ultimate strength of the MEA increases almost linearly from 1326 to 1695 MPa as the temperature decreases from 293 to 113 K,while the total elongation remains approximately constant of~35%.The underlying deformation and strengthening mechanisms were investigated using various characterization techniques.Due to the effect of co-doped Al/Ti on channel width of the matrix and the increasing critical twinning stress induced by heterogeneous ultrafine grain size,the formation of deformation twins is inhibited at all temperatures.Consequently,only a slight increase of the deformation twins and stacking faults in the deformed specimens with a decreasing temperature,which leads to the relative temperature-independence of the ductility.The dislocation cutting mechanism of L1_(2) coherent precipitates and the heterodeformation induced(HDI)hardening both significantly contribute to the strain hardening so that an excellent combination of strength and ductility is obtained.Additionally,the evolution of lattice friction stress with deformation temperature is determined by quantitative analysis,indicating an approximately linear relationship between the lattice friction and temperature.The present work provides new insights into the strategy of achieving outstanding strength-ductility synergy of the MEA under the wide temperature range by coupling heterogeneous ultrafine-grained structure and coherent precipitation strategy.

关键词： medium entropy alloy cryogenic temperature heterogeneous structure precipitation strengthening twinning

Development of an experimental method for well-controlled blast induced traumatic limb fracture in rats

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Defence Technology（防务技术） 2024年第4期34卷 168-176页

作者： Luyang Xu Xiancheng YU Clement DFavier Ibidumo Igah Thuy-Tien Nguyen Warren Macdonald Anthony MJ.Bull Centre for Blast Injury Studies Imperial College LondonLondonUnited Kingdom Department of Bioengineering Imperial College LondonLondonUnited Kingdom Dyson School of Design Engineering Imperial College LondonLondonUnited Kingdom Department of Trauma and Orthopaedics Royal Free London National Health Service Foundation TrustLondonUnited Kingdom

Heterotopic ossification(HO)is a consequence of traumatic bone and tissue damage,which occurs in 65%of military casualties with blast-associated amputations.However,the mechanisms behind blast-induced HO remain unclear.Animal models are used to study blast-induced HO,but developing such models is challenging,particularly in how to use a pure blast wave(primary blast)to induce limb fracture that then requires an amputation.Several studies,including our recent study,have developed platforms to induce limb fractures in rats with blast loading or a mixture of blast and impact loading.However,these models are limited by the survivability of the animal and repeatability of the model.In this study,we developed an improved platform,aiming to improve the animal's survivability and injury repeatability as well as focusing on primary blast only.The platform exposed only one limb of the rat to a blast wave while providing proper protection to the rest of the rat's body.We obtained very consistent fracture outcome in the tibia(location and pattern)in cadaveric rats with a large range of size and weight.Importantly,the rats did not obviously move during the test,where movement is a potential cause of uncontrolled injury.We further conducted parametric studies by varying the features of the design of the platform.These factors,such as how the limb is fixed and how the cavity through which the limb is placed is sealed,significantly affect the resulting injury.This platform and test setups enable well-controlled limb fracture induced directly by pure blast wave,which is the fundamental step towards a complete in vivo animal model for blast-induced HO induced by primary blast alone,excluding secondary and tertiary blast injury.In addition,the platform design and the findings presented here,particularly regarding the proper protection of the animal,have implications for future studies investigating localized blast injuries,such as blast induced brain and lung injuries.

关键词： Blast injury Biomechanics Heterotopic ossification Limb fracture Blast wave Animal model

Effects of post annealing on the microstructure,precipitation behavior,and mechanical property of a(CoCrNi)_(94)Al_(3)Ti_(3)medium-entropy alloy fabricated by laser powder bed fusion

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Journal of Materials Science & Technology 2023年第4期135卷 142-155页

作者： Zhuang Li Pengcheng Zhao Tiwen Lu Kai Feng Yonggang Tong Binhan Sun Ning Yao yu Xie Bolun Han xiancheng Zhang Shantung Tu Key Laboratory of Pressure Systems and Safety Ministry of EducationSchool of Mechanical and Power EngineeringEast China University of Science and TechnologyShanghai 200237China Shanghai Key Laboratory of Materials Laser Processing and Modification School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China College of Automobile and Mechanical Engineering Changsha University of Science and TechnologyChangsha 410114China

The additive manufacturing of multi-principal element alloys has remarkable potential for industrial ap-plications.In this study,a(CoCrNi)_(94)Al_(3)Ti_(3)medium-entropy alloy(MEA)with adequate strength-ductility synergy was prepared via laser powder bed fusion.The microstructural evolution,mechanical property,and deformation mechanisms of the MEA were investigated after post annealing for a short period(0.5 h)at a temperature range of 773-1373 K using various microstructural characterization techniques and quantitative analysis.The static recrystallization temperature of the(CoCrNi)_(94)Al_(3)Ti_(3)MEA ranged from 973 to 1073 K.The average grain size first decreased and then increased,while the dislocation den-sity persistently decreased and texture gradually weakened with increasing annealing temperature.Cr-richσ-phase precipitates formed after 1073 K and then gradually dissolved at 1373 K,while Ni,Al,and Ti elements were aggregated to form a small amount of fine L1_(2)coherent precipitates with an aver-age diameter of approximately 70 nm at 1373 K.The evolution of the dislocation density,grain size,and precipitates significantly influenced the propensity of deformation twins and stacking faults,which consequently affected the strain hardening behavior and mechanical properties.The quantitative calcu-lation of strengthening mechanisms showed that dislocation strengthening played a dominant role at annealing temperatures below 1073 K,and it significantly weakened at 1373 K.Precipitation and grain boundary strengthening both markedly increased owing to the formation of precipitation particles and recrystallization-induced grain refinement after annealing at 1073 K.

关键词： Medium-entropy alloy Additive manufacturing Heat treatment Strengthening mechanism Microstructural evolution

Colossal negative magnetoresistance in spin glass Na(Zn,Mn)Sb

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Journal of Semiconductors 2023年第3期44卷 62-67页

作者： Shuang yu Yi Peng Guoqiang Zhao Jianfa Zhao xiancheng Wang Jun Zhang Zheng Deng Changqing Jin Beijing National Laboratory for Condensed Matter Physics and Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physics University of Chinese Academy of SciencesBeijing 100190China

We report the study of magnetic and transport properties of polycrystalline and single crystal Na(Zn,Mn)Sb,a new member of“111”type of diluted magnetic materials.The material crystallizes into Cu2Sb-type structure which is isostructural to“111”type Fe-based superconductors.With suitable carrier and spin doping,the Na(Zn,Mn)Sb establishes spin-glass ordering with freezing temperature(Tf)below 15 K.Despite lack of long-range ferromagnetic ordering,Na(Zn,Mn)Sb single crystal still shows sizeable anomalous Hall effect below Tf.Carrier concentration determined by Hall effect measurements is over 1019 cm-3.More significantly,we observe colossal negative magnetoresistance(MR≡[ρ(H)−ρ(0)]/ρ(0))of-94%in the single crystal sample.

关键词： colossal negative magnetoresistance spin glass diluted magnetic materials

全身麻醉下个体化病人体温调节反应的计算机仿真

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医用生物力学 2020年第2期35卷 163-170页

作者：俞快张现成刘浩上海交通大学船舶海洋与建筑工程学院上海200240 上海交通大学千叶大学国际合作研究中心上海200240 中国科学深圳先进技术研究院广东深圳518055 日本千叶大学工学院千叶263-8522

目的通过构建计算机仿真模型分析全身麻醉引起的体温调节系统损伤和手术室低温环境对个体化病人围手术期体温调节的影响。方法开发一个麻醉模型,通过降低基本代谢率、皮下血管收缩和骨骼肌颤抖的阈值来模拟麻醉效果,并耦合到作者建立的... 详细信息

目的通过构建计算机仿真模型分析全身麻醉引起的体温调节系统损伤和手术室低温环境对个体化病人围手术期体温调节的影响。方法开发一个麻醉模型,通过降低基本代谢率、皮下血管收缩和骨骼肌颤抖的阈值来模拟麻醉效果,并耦合到作者建立的"皮肤-体核"二节点体温调节模型中。该模型可通过设置骨骼肌颤抖产热、出汗、及皮下血管舒缩能力的强弱模拟年龄衰老导致的热调节能力损伤,设置不同脂肪厚度模拟肥胖以及设置心血管模型参数模拟不同的心血管疾病,进而计算分析这些个体化特征对低温麻醉条件下体温调节的影响。结果在低温环境下,与年轻人相比,老年人体核温度较低,体表温度较高。脂肪厚度增加或左心室功能衰竭加重,都有可能缓解低温环境中体核温度下降。风速或相对湿度增加会导致体核温度降低。当麻醉引起的血管收缩阈值降低0.5~3℃时,会引起体核温度显著降低。结论通过对比模型预测与实验测量的结果,验证了该模型的可靠性。身体的个体化特征对低温环境下人体温度调节具有重要影响。个体体征与全身麻醉结合进一步复杂化了人体的体温调节,给临床医师带来巨大挑战。

关键词：人体体温调节生物热传导模型全身麻醉围手术期低体温个体化特征

赞助事实揭露与否下微信营销信息质量对分享意愿的影响研究

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上海管理科学 2022年第5期44卷 90-95页

作者：连宪成余明阳上海交通大学安泰经济与管理学院上海200030

影响力营销可将微信作为执行平台,已有许多微信第三方公众号与产品厂商合作,其以代言人式的营销期望扩大信息分享范围,然而存在营销过程中是否揭示收受厂商赞助的差异处。因此,主要研究信息质量对于用户分享意愿的效应,并检验赞助事实... 详细信息

影响力营销可将微信作为执行平台,已有许多微信第三方公众号与产品厂商合作,其以代言人式的营销期望扩大信息分享范围,然而存在营销过程中是否揭示收受厂商赞助的差异处。因此,主要研究信息质量对于用户分享意愿的效应,并检验赞助事实揭露在其中的调节效果。实验结果显示:(1)当微信营销信息质量较高时,用户将有相对高的信息可信度感知,从而引发更高的信息分享意愿;(2)当微信营销过程中进行产品厂商赞助事实明确揭露时,会抑制用户的信息分享意愿。

关键词：微信营销赞助事实揭露信息质量信息可信度分享意愿

Superconducting properties of “111” type LiFeAs iron arsenide single crystals

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Science China(Physics,Mechanics & Astronomy) 2010年第7期53卷 1199-1201页

作者： xiancheng Wang QingQing Liu yuXi Lv Zheng Deng Kan Zhao RiCheng yu JinLong Zhu ChangQing Jin Chinese Acad Sci Inst Phys Beijing 100190 Peoples R China

LiFeAs single crystal has been grown with superconducting transition temperature Tc comparable to that of polycrystals.A magnetic transition is found at about 160 K,which suggests the correlation of superconductivity ... 详细信息

关键词： iron based superconductor LiFeAs magnetic order