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Deformation bands in fully pearlitic steel during wire drawing

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Science China(Technological Sciences) 2014年第4期57卷 796-803页

作者： GUO Ning SONG Bo LUAN BaiFeng chen zhiqian LIU Qing School of Materials Science and Engineering Southwest University School of Materials Science and Engineering Chongqing University

The deformation of fully pearlitic steels during wire drawing has been investigated for botb longitudinal section and transverse section by back-scattered electron imaging （BSEI）, electron back-scattered diffraction （EBSD）, and transmission electron mi- croscope （TEM）. The results show that a large number of deformation bands （DBs） composed of a mixture of kink-like bands and shear-like bands were observed both in the longitudinal section and the traverse section of the drawn wires. The formation of such bands involves two aspects： heterogeneous deformation in the scale of pearlite colonies and instability of fer- rite-cementite interfaces due to stress concentration during wire drawing. The development of suck bands in fully pearlitic steels dominates the formation of metallograpbic texture, reduces the pearlite interlamellar spacing and promotes the development of 〈 110〉 fiber crystalline texture of ferrite matrix during wire drawing.

关键词： pearlitic steel wire drawing deformation bands microstructure

LiBH4 for hydrogen storage-New perspectives

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Nano Materials Science 2020年第2期2卷 109-119页

作者： Zhao Ding Shaoyuan Li Yang Zhou zhiqian chen Weijie Yang Wenhui Ma Leon Shaw Department of Mechanical Materials and Aerospace EngineeringIllinois Institute of TechnologyChicagoIL60616USA Faculty of Metallurgical and Energy Engineering Kunming University of Science and TechnologyKunming650091China School of Photovoltaic and Renewable Energy Engineering University of New South WalesSydneyNSW2052Australia School of Textile Science and Engineering State Key Laboratory of New Textile Materials and Advanced Processing TechnologyWuhan Textile UniversityWuhan430200China Department of Computer Science Virginia TechFalls ChurchVA22043USA School of Energy and Power Engineering North China Electric Power UniversityBaoding071003China

Hydrogen energy has been recognized as“Ultimate Power Source”in the 21st *** is a boon in these days of energy crunches and concerns about climate change because of the characterized advantages,such as high energy density,large calorific value,abundant resource,zero pollution,zero carbon emission,storable and ***-of-the-art perspectives on tuning the stable thermodynamics and sluggish kinetics of dehydrogenation and re-hydrogenation of LiBH4,which has been regarded as a promising hydrogen storage alternative for onboard energy carrier applications have been *** major technological approaches are involved,including nanoengineering,catalyst modification,ions substitution,reactant destabilization and a novel process termed as high-energy ball milling with in-situ aerosol spraying(BMAS).It is worth noting that BMAS has the potential to help overcome the kinetic barriers for thermodynamically favorable systems like LiBH4 t MgH2 mixture and provide thermodynamic driving force to enhance hydrogen release at a lower temperature.

关键词： Hydrogen storage materials LiBH4 Nanoengineering MgH2 BMAS

Autologous fibroblasts induce fibrosis of the nucleus pulposus to maintain the stability of degenerative intervertebral discs

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Bone Research 2020年第1期8卷 63-75页

作者： chen chen Tangjun Zhou Xiaojiang Sun chen Han Kai Zhang Changqing Zhao Xunlin Li Haijun Tian Xiao Yang Yifan Zhou zhiqian chen An Qin Jie Zhao Shanghai Key Laboratory of Orthopaedic Implants Department of Orthopaedic Surgery Shanghai Ninth People’s Hospital Shanghai Jiao Tong University School of Medicine

Lumbar degenerative disc diseases cause low back pain(LBP). The maintenance of the height and stability of the intervertebral disc(IVD) space is an effective treatment for LBP. The following study evaluated the effects of fibroblast injection on intervertebral disc degeneration(IDD) in a preclinical setting. Compared with the IDD group, the fibroblast treatment group demonstrated effective maintenance of IVD height, reduced endplate degeneration, and improved nuclear magnetic resonance signals and overall histological structure. In doing so, fibrotic IVDs maintained the stability and biomechanics of the vertebra. This finding is in agreement with clinical findings that human nucleus pulposus(NP) fibrosis is essential for the maintenance of IVD height and mechanical properties in patients following percutaneous endoscopic lumbar discectomy(PELD). Mechanistically, we demonstrated that injected fibroblasts not only proliferated but also induced NP cells to adopt a fibrotic phenotype via the secretion of TGF-β.Finally, to better mimic human conditions, the efficacy of autologous fibroblast injection in the treatment of IDD was further examined in a nonhuman primate cynomolgus monkey model due to their capacity for upright posture. We showed that the injection of fibroblasts could maintain the IVD height and rescue IVD signals in cynomolgus monkeys. Taken together, the results of our study reveal that autologous fibroblast injection can enhance the natural process of fibrosis during acute and subacute stages of stress-induced IDD. Fibrotic IVDs can maintain the stability, biological activity, and mechanical properties of the intervertebral space, thus providing a new direction for the treatment of intervertebral space-derived lumbar degenerative diseases.

关键词： intervertebral degenerative degeneration

High-strength wrought magnesium alloy with dense nano-scale spherical precipitate

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Chinese Science Bulletin 2007年第13期52卷 1867-1871页

作者： YU WenBin chen zhiqian chenG NanPu GAN BingTai HE Hong LI XueLian HU JinZhu School of Materials Science and Engineering Southwest University Chongqing 400715 China

This paper reported the influences of Yb addition on the precipitate and mechanical properties of wrought magnesium alloy ZK60. The ingots of ZK60-1.78Yb (wt%, 0.26 at%) alloys were cast using permanent mould and extruded at 370℃ . By means of TEM and HRTEM, it was observed that Yb affected the precipitate and precipitation of ZK60-1.78Yb alloys significantly. Dynamic precipitation occurred in the as-extruded alloy and spherical nano-scale precipitate with high density and homoge-neity exhibited in the aged alloys. The precipitate particles were about 5-20 nm in diameter, 10-30 nm in average space length. The tensile test results showed that the ZK60-1.78Yb alloy had excellent pre-cipitation strengthening response with the maximum tensile strength 417.5 MPa at ambient tempera-ture.

关键词：镁合金镱元素动力学沉淀物张力强度

Polyphenol based hybrid nano-aggregates modified collagen fibers of biological valve leaflets to achieve enhanced mechanical,anticoagulation and anti-calcification properties

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Journal of Leather Science and Engineering 2022年第4期4卷 394-408页

作者： Shufen Li Shiying Lang zhiqian chen Jingruo chen Weihua Zhuang Yangrui Du Yawen Yao Gongyan Liu Mao chen Laboratory of Heart Valve Disease West China HospitalSichuan University37 Guoxue AlleyChengdu 610041China The Key Laboratory of Leather Chemistry and Engineering of Ministry of Education College of Biomass Science and EngineeringSichuan UniversityChengdu 610065China University of California Davis 1 Shields AveDavisCA 95616USA Faculty of Science and Engineering Aachen-Maastricht Institute for Biobased Materials(AMIBM)Maastricht UniversityBrightlands Chemelot Campus6167 RD GeleenThe Netherlands Department of Cardiology West China HospitalSichuan University37 Guoxue AlleyChengdu 610041China Regenerative Medicine Research Center West China HospitalSichuan University37 Guoxue AlleyChengdu 610041China

Glutaraldehyde(Glut)-crosslinked porcine pericardium and bovine pericardium are mainly consisted of collagen and widely used for the preparation of heterogenous bioprosthetic heart valves(BHV),which play an important role in the replacement therapy of severe valvular heart disease,while their durability is limited by degeneration due to calcification,thrombus,endothelialization difficulty and prosthetic valve ***,we develop a novel BHV,namely,TPly-BP,based on natural tannic acid and polylysine to improve the durability of Glut crosslinked bovine pericardium(Glut-BP).Impressively,tannic acid and polylysine could form nanoaggregates via multiple hydrogen bonds and covalent bonds,and the introduction of nanoaggregates not only improved the mechanical properties and collagen stability but also endowed TPly-BP with good biocompatibility and *** to Glut-BP,TPly-BP showed significantly reduced cytotoxicity,improved endothelial cell adhesion,a low hemolysis ratio and obviously reduced platelet ***,TPly-BP exhibited great antibacterial and in vivo anti-calcification ability,which was expected to improve the in vivo durability of *** results suggested that TPly-BP would be a potential candidate for BHV.

关键词： Tannic acid Bioprosthetic heart valve Antibacterial and anti-calcification

The Properties of Elasticity, Thermology, and Anisotropy in Pd-Based Alloys

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Journal of Materials Science and Chemical Engineering 2017年第3期5卷 17-34页

作者： Kuankuan chen Meng Hu Chunmei Li Guannan Li zhiqian chen Faculty of Materials and Energy Southwest University Chongqing China

This work is devoted to investigate the elasticity, anisotropy, plastic properties, and thermal conductivity of PdSnYb, PdSn2Yb and Heusler alloy Pd2SnYb via employing the first-principles. The magnetic properties of Pd2SnYb, PdSnYb and PdSn2Yb are obtained by the geometry optimization combining with spin polarization. And the stability of these three kinds of materials is ensured by comparing with the enthalpy of formation and binding energy. The Fermi energy has same trend with stability. The details of bulk and Young’s modulus are demonstrated in 3D plots, embodied the elastic anisotropies of PdSnYb, PdSn2Yb, and Pd2SnYb. The calculations of plastic properties are also anisotropic. And the minimum thermal conductivities are small enough for these three materials to be used as thermal barrier coatings.

关键词： First-Principles Pd-Based Alloys Elasticity Thermal Conductivity Anisotropy

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基于传导思维的人防工程专项规划编制方法

地下空间与工程学报 2024年第2期20卷 369-377页

作者：陈智乾江苏省规划设计集团江苏省城镇与乡村规划设计院有限公司南京210000

伴随着新时期国土空间规划体系的建立,新一轮人防工程专项规划编制需要与时俱进,不断提升其传导思维,以解决现行人防工程专项规划与城市规划衔接不够、内容传导不足等问题。本文首先阐述了国土空间专项规划横向、纵向以及内在三方面的... 详细信息

伴随着新时期国土空间规划体系的建立,新一轮人防工程专项规划编制需要与时俱进,不断提升其传导思维,以解决现行人防工程专项规划与城市规划衔接不够、内容传导不足等问题。本文首先阐述了国土空间专项规划横向、纵向以及内在三方面的传导需求,并基于以上需求,提出新一轮人防工程专项规划的编制框架及编制要点,结合A城市规划实践,从"加强现状问题识别传导规划目标、强化市域综合防护体系建设引导、突出城区人防工程体系逐级传导、构建防空区片管控要素传导机制、加强规划传导促进各类空间融合"五方面详细阐述了传导需求在具体城市人防工程专项规划中如何落实,期望为新时期人防工程专项规划的编制提供参考和借鉴。

关键词：传导思维国土空间规划体系人防工程编制方法

电网对称故障下定速异步风电场STATCOM容量配置研究

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电工技术学报 2016年第1期31卷 45-54页

作者：姚骏周特陈知前输配电装备及系统安全与新技术国家重点实验室(重庆大学) 重庆400044

从建立并网异步风电场简化等效模型出发,详细分析了含线路参数的大容量异步风电场暂态特性和功率特性,并在此基础上定量分析了异步风电场的临界切除时间与无功设备补偿容量间的关系,最终提出了基于风电场转矩特性和功率潮流的大容量异... 详细信息

从建立并网异步风电场简化等效模型出发,详细分析了含线路参数的大容量异步风电场暂态特性和功率特性,并在此基础上定量分析了异步风电场的临界切除时间与无功设备补偿容量间的关系,最终提出了基于风电场转矩特性和功率潮流的大容量异步风电场静止同步补偿器的容量配置方法。该配置方法可计算满足电网导则中低电压穿越要求的大容量异步风电场所需配置的最小静止同步补偿器无功补偿设备容量,并通过仿真平台验证了所提计算方法的正确性。最后对影响异步风电场的低电压穿越能力的相关因素进行了深入分析,揭示了大电网与异步风电场间电气距离与其所需配置静止同步补偿器设备容量间的关系以及静止同步补偿器配置容量对异步风电场暂态运行特性的影响。

关键词：定速异步风电场低电压穿越静止同步补偿器容量配置暂态特性分析

First-principles investigation of mechanical and electronic properties of LaAg5 Laves phase under pressure

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Journal of Rare Earths 2016年第1期34卷 105-112页

作者：高恩强黄福祥陈志谦王兰兰张照超 College of Materials Science & Engineering Chongqing University of Technology Chongqing 400054 China Faculty of Materials and Energy Southwest University Chongqing 400715 China

The effects of applied pressure on the structural, mechanical, and electronic properties of LaAgs compound were investi- gated employing the first-principles method based on the density fimctional theory. The mechanical results demonstrated that bulk modulus, shear modulus and Young＇s modulus presented the linearly increasing dependences on the external pressure; the B/G and Poisson＇s ratio indicated that LaAg5 compound was a ductile material with central forces in interatomic under pressure from 0 to 40 GPa; the universal anisotropic index was performed to investigate the elastic anisotropic of LaAgs. Additionally, the pressure de- pendence of the density of states and Mulliken charge were also discussed. The bonding characterization in LaAg5 was composed of metallic, covalent and ionic. The metallic component was derived from free-electron transferring from Ag-s and Ag-d to Ag-p, and from La-s to La-d. The ionic component was due to the charge movement from La to Ag. The covalent was owing to Ag-p-La-d bonding hybridization and Ag-s-Ag-p in the Ag atomic chains. The covalent and ionic bonds were stronger under pressure but there was no significant change in metallic nature.

关键词： LaAg5 Laves phase elastic properties electric structure density functional theory rare earths