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累积叠轧工艺对AA3003铝合金显微组织和性能的影响

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机械工程材料 2019年第10期43卷 41-46页

作者：赖春明李泽志秦南张麦秋王明湖南化工职业技术学院中南大学材料科学与工程学院新兴铸管股份有限公司

对AA3003铝合金板进行4道次累积叠轧加工,研究了不同道次累积叠轧后铝合金板的显微组织、拉伸性能和成形性能。结果表明:随着叠轧道次的增加,铝合金板中晶粒发生细化并趋于等轴形状,板厚方向上的组织均匀性增强;累积叠轧铝合金板的中心... 详细信息

对AA3003铝合金板进行4道次累积叠轧加工,研究了不同道次累积叠轧后铝合金板的显微组织、拉伸性能和成形性能。结果表明:随着叠轧道次的增加,铝合金板中晶粒发生细化并趋于等轴形状,板厚方向上的组织均匀性增强;累积叠轧铝合金板的中心层主要为轧制织构,表层主要为剪切织构;累积叠轧工艺提高了铝合金板的强度,但降低了其塑性和成形性能,随着叠轧道次的增加,铝合金板的屈服强度和抗拉强度增大、伸长率变化不大、成形性能略微下降。

关键词：累积叠轧 AA3003铝合金显微组织拉伸性能织构

Realizing high thermoelectric performance for p-type SiGe in medium temperature region via TaC compositing

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Journal of Materiomics 2023年第5期9卷 984-991页

作者： Zheng Fan JiSheng Liang Jun-Liang Chen Ying Peng Huajun lai Jian Nong Chengyan Liu Wangyang Ding Lei Miao Guangxi Key Laboratory for Relativity Astrophysics State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite StructuresSchool of Physical Science and TechnologyGuangxi UniversityNanning530004China engineering Research Center of Electronic Information Materials and Devices Ministry of EducationGuangxi Key Laboratory of Information MaterialGuilin University of Electronic TechnologyGuilin541004China Guangxi Key Laboratory of Precision Navigation technology and Application Guilin University of Electronic TechnologyGuilin541004China Guangxi Academy of sciences Nanning530007China

SiGe is recognised as an excellent thermoelectric material with superior mechanical properties and thermal stability in regions with high *** study explores a novel strategy for coregulating thermoelectric transport parameters to achieve high thermoelectric properties of p-type SiGe in the mid-temperature region by incorporating nano-TaC into SiGe combined ball milling with spark plasma *** optimizing the amount of TaC in the SiGe matrix,the power factors were significantly increased due to the modulation doping effect based on the work function matching of SiGe with ***,the ensemble effect of the nanostructure leads to a significant decrease in thermal ***,a high ZT of 1.06 was accomplished at 873 K,which is 64%higher than that of typical radioisotope thermoelectric *** research offers a novel strategy for expanding and enhancing the thermoelectric properties of SiGe materials in the medium temperature range.

关键词： SiGe Thermoelectric Work function matching Modulation doping effect Phonon scattering

Predicting the electromechanical properties of small caliber projectile impact igniter using PZT dynamic damage constitutive model considering crack propagation

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Defence technology（防务技术） 2023年第10期28卷 121-135页

作者： Rui-zhi Wang Zhi-qiang Wang En-ling Tang Lei Li Guo-lai Yang Chun Cheng Li-ping He Ya-fei Han Key Laboratory of Transient Physical Mechanics and Energy Conversion Materials of Liaoning Province Shenyang Ligong UniversityShenyang110159LiaoningChina school of mechanical engineering Nanjing University of Science and TechnologyNanjing210094JiangsuChina Key Laboratory of Impact and Safety engineering Ministry of EducationNingbo UniversityNingbo315211ZhejiangChina

Block piezoelectric ceramics(PZTs)are often used in impact igniters to provide activation energy for electric *** the action of strong impact stress,PZTs release electric energy accompanied by crack initiation,propagation and *** present,the electrical output performance of PZTs in projectile is usually calculated by quasi-static piezoelectric equation without considering the dynamic effect caused by strong impact and the influence of crack propagation on material *** the ignition parameters are always not accurately *** tackle this,a PZT dynamic damage constitutive model considering crack propagation is established based on the dynamic impact test and the crack propagation theory of brittle *** model is then embedded into the ABAQUS subroutine and used to simulate the electromechanical response of the impact igniter during the impact of a small caliber projectile on the ***,the experiments of projectile with impact igniter impact on the target are carried *** comparison between experimental and numerical simulation results show that the established dynamic damage model can effectively predict the dynamic electromechanical response of PZTs in the missile service environment.

关键词： Piezoelectric ceramics Impact Igniter Dynamic damage constitutive model Electromechanical response

Study on microscale adhesion between solid surfaces with scanning probe

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science china(Technological sciences) 2013年第12期56卷 2934-2952页

作者： lai TianMao HUANG Ping school of mechanical and Automotive engineering South China University of Technology

The adhesion between two parallel solid surfaces is of great interest with the rapid development of micro-nano devices and *** adhesion forces between a flat tip with a diameter^1.7μm and some surface have been determined by recording the force-displacement curves with an atomic force microscope(AFM).The flat tip is used to prevent wear and mimic the adhesion between two parallel *** free energy of the solid surface is calculated by the contact angles between the probe liquids and the *** adhesion force between parallel solid surfaces cannot be predicted by the theory of thermodynamic surface free *** adhesion measurements were carried out under ambient conditions,in a nitrogen-filled glove box,under distilled water,and under potassium chloride(KCl)*** outcome shows that the real contact area without the applied load is only a small proportion of the apparent contact *** measurement stability and repeatability of adhesion by the AFM depend on the surface characterization,measurement methods and the *** different environments,there are different interactions and factors affecting the adhesion force,and the dominant interactions and factors may be different *** various interactions and factors are mutually coupled to determine the final adhesion force.

关键词：固体表面粘附力扫描探针微尺度表面自由能原子力显微镜测量方法相互作用

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氧化淀粉的抑菌效果及草莓涂膜保鲜应用

食品科学 2022年第21期43卷 324-331页

作者：陈卓宋俏微张水洞胡长鹰暨南大学理工学院广东广州510632 暨南大学包装工程学院广东省普通高校产品包装与物流重点实验室广东珠海519070 华南理工大学机械与汽车工程学院广东广州510640

本实验采用抑菌圈法研究氧化淀粉(oxidized starch,OST)的抑菌作用,通过测定草莓的质量损失率、腐烂率、菌落总数等理化指标研究OST对草莓的保鲜效果。结果表明:OST对常见致病菌金黄色葡萄球菌、大肠杆菌和常见草莓腐败菌青霉菌均具有... 详细信息

本实验采用抑菌圈法研究氧化淀粉(oxidized starch,OST)的抑菌作用,通过测定草莓的质量损失率、腐烂率、菌落总数等理化指标研究OST对草莓的保鲜效果。结果表明:OST对常见致病菌金黄色葡萄球菌、大肠杆菌和常见草莓腐败菌青霉菌均具有明显的抑菌效果,OST中羧基相对含量越高则抑菌能力越强,其中羧基相对含量达57%的OST(OST-57)对金黄色葡萄球菌、大肠杆菌和青霉菌形成的抑菌圈直径分别为(29.00±0.87)、(28.00±1.73)、(15.75±0.65)mm;与未经处理草莓相比,OST-57对草莓的涂膜处理能够有效抑制菌落总数增长,显著降低草莓质量损失率和腐烂率(P<0.05),延缓草莓成熟过程中硬度和咀嚼性的变化,同时能够显著维持可溶性固形物和花色苷等营养物质含量(P<0.05)。结论:OST-57浸泡涂膜处理能够更有效地延缓草莓果实的成熟衰老,可作为新型的果蔬涂膜材料,对于果蔬的采后保鲜具有应用价值。

关键词：氧化淀粉抑菌涂膜草莓保鲜

Numerical Study of Controlling Jet Flow and Noise using Pores on Nozzle Inner Wall

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Journal of Thermal science 2018年第2期27卷 146-156页

作者： LIN Jian SHI Zhixiao lai Huanxin school of mechanical and Power engineering East China University of Science and Technology

In this paper, the feasibility of controlling the subsonic jet flow and its noise using pores of blind holes added on the nozzle inner wall is explored numerically. These pores are intended to introduce disturbances to the shear layer so as to change the flow mixing. This passive strategy has not been attempted so far.A convergent nozzle with a cylindrical extension is selected as the baseline case. Three nozzles with pores on the inner wall are set up. Validations of the numerical settings are carried out, then the compressible turbulent jets at the exit Mach number M_j=0.6 in the four nozzles are calculated by large eddy simulations(LES), while the radiated sounds are predicted by the FW-H acoustic analogy. The results show that the blind holes have produced some effects on weakening the turbulence intensity in the shear layer. Comparison reveals that both temporal and spatial correlations of the turbulent fluctuations in the modified cases are suppressed to some extent. Meanwhile,the porous nozzles are shown to suppress the pairing of vortices and enhance the flow mixing, and therefore, the development of shear layer and the fragmentation of large scale vortices are accelerated.

关键词：流动毛孔喷气噪音控制大旋涡模拟学习墙

Numerical Study of Unsteady Flows with Cavitation in a High-Speed MicroCentrifugal Pump

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Journal of Thermal science 2017年第1期26卷 18-24页

作者： LI Yeqiang YUAN Shiwei lai Huanxin school of mechanical and Power engineering East China University of Science and Technology Shanghai 200237China. Shanghai First Fluid Machinery Co. Ltd Shanghai 201709 China.

The unsteady flows caused by the interaction between the impeller and the volute in a high-speed micro centrifugal pump are numerically studied. The internal flows of both with and without cavitations are analyzed using the CFX. The characteristics of unsteady pressure on the blade surfaces and the symmetric plane of the volute are presented and compared. The results show that the amplitudes of pressure fluctuations of critical cavitation on the blade pressure surface(PS) are bigger as compared with those at the non-cavitation condition, but on the suction surface(SS), the situation is on the contrary. When cavitation occurs, reduction of load in the impeller is a result. In the present study, such reduction of load is observed mainly on the first half of the blades. Pressure fluctuations at five monitoring points, denoted by WK1 to WK5 in the volute, are also analyzed. No matter at the critical cavitation or at the non-cavitation conditions, the monitored pressure fluctuations are at the same frequencies, which equal to the blade passing frequency(BPF) and its multiples. However, the amplitudes of the fluctuations at critical cavitation condition are considerably stronger, as compared with those for without cavitation.

关键词： Micro-centrifugal pump, Unsteady flow, Cavitation, Pressure fluctuation.

Mitigating thermal runaway hazard of high-energy lithium-ion batteries by poison agent

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能源化学:英文版 2023年第8期83卷 3-15,I0002页

作者： Xin lai Zheng Meng Fangnan Zhang Yong Peng Weifeng Zhang Lei Sun Li Wang Fei Gao Jie Sheng Shufa Su Yuejiu Zheng Xuning Feng school of mechanical engineering University of Shanghai for Science and TechnologyShanghai 200093China svoLT Energy technology Co.Ltd Changzhou 213200JiangsuChina State Key Laboratory of Automotive Safety and Energy Tsinghua UniversityBeijing 100084China State Grid Jiangsu Electric Power Co. LtdNanjing 211103JiangsuChina

Lithium-ion batteries with high-energy density are extensively commercialized in long-range electric vehicles. However, they are poor in thermal stability and pose fire or explosion, which has attracted the global attention. This study describes a new route to mitigate the battery thermal runaway(TR) hazard by poison agents. First, the self-destructive cell is built using the embedded poison layer. Then, the poisoning mechanism and paths are experimentally investigated at the material, electrode, and cell levels. Finally, the proposed route is verified by TR tests. The results show the TR hazard can be significantly reduced in the self-destructive cell based on a new reaction sequence regulation. Specifically, the maximum temperature of the self-destructive cell is more than 300℃ lower than that of the normal cell during TR. The drop in maximum temperature can reduce total heat release and the probability of TR propagation in the battery system, significantly improving battery safety.

关键词： Energystorage Lithium-ionbatteries Thermal runaway Self-poison Chemical reactions

Nanometric polishing of lutetium oxide by plasma-assisted etching

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Advances in Manufacturing 2020年第4期8卷 440-446页

作者： Peng Lyu Min lai Feng-Zhou Fang State Key Laboratory of Precision Measuring technology and Instruments Centre of Micro/Nano Manufacturing Technology(MNMT)Tianjin UniversityTianjin 300072People’s Republic of China Centre of Micro/Nano Manufacturing technology(MNMTDublin) School of Mechanical and Materials EngineeringUniversity College Dublin.Dublin 4Ireland

Plasma-assisted etching,in which the irradiation of hydrogen plasma and inorganic acid etching are integrated,is proposed as a novel polishing method for sesquioxide *** means of this approach,low damage and even damage-free surfaces with a high material removal rate can be achieved in lutetium oxide surface *** of transmission electron microscopy and X-ray photoelectron spectroscopy reveal that plasma hydrogenation converts the sesquioxide into hydroxide,which leads a high efficient way to polish the *** influences of process conditions on the etching boundary and surface roughness are also qualitatively investigated using scanning electron microscope and white light *** newly developed process is verified by a systematic experiment.

关键词： Plasma-assisted etching Lutetium oxide Surface roughness Subsurface damage