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A comparative study of using two numerical strategies to simulate the biochemical processes in microbially induced calcite precipitation

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Journal of Rock Mechanics and Geotechnical engineering 2022年第2期14卷 592-602页

作者： Dianlei Feng Xuerui wang Udo Nackenhorst Xuming Zhang Pengzhi Pan Department of Hydraulic engineering Tongji UniversityShanghai200092China institute of fluid Mechanics and Environmental physics in Civil engineering Leibniz University HannoverHannover30167Germany institute of Mechanics and Computational Mechanics Leibniz University HannoverHannover30167Germany State Key Laboratory of Geomechanics and Geotechnical engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China

In this study,we carried out a comparative study of two different numerical strategies for the modeling of the biogeochemical processes in microbially induced calcite precipitation(MICP)process.A simplified MICP model was used,which is based on the mass transport *** numerical strategies,namely the operator splitting(OS)and the global implicit(GI)strategies,were adopted to solve the coupled reactive mass transport *** two strategies were compared in the aspects of numerical accuracy,convergence property and computational efficiency by solving the presented MICP *** look more into the details of the model,sensitivity analysis of some important modeling parameters was also carried out in this paper.

关键词： Microbially induced calcite precipitation(MICP) Advection-diffusion-reaction(ADR)equation Time discontinuous Galerkin(TDG)method Open Geo Sys-PHREEQC

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多孔平衡式液氢流量计的流动特性研究

低温工程 2024年第2期 8-14,77页

作者：田一含崔晨高诏诏陈六彪王俊杰中国科学院理化技术研究所低温科学与技术重点实验室北京100190 中国科学院大学北京100049 齐鲁中科光物理与工程技术研究院济南250000

设计并加工了一种具有流阻小、无运动部件的多孔平衡流量计,在使用初步实验数据验证建立的仿真模型准确性基础上,仿真分析了入口流速、液氢过冷度、内壁面粗糙度、入口气相含率对流出系数、压力损失系数和空化特性的影响。结果表明,在... 详细信息

设计并加工了一种具有流阻小、无运动部件的多孔平衡流量计,在使用初步实验数据验证建立的仿真模型准确性基础上,仿真分析了入口流速、液氢过冷度、内壁面粗糙度、入口气相含率对流出系数、压力损失系数和空化特性的影响。结果表明,在孔板结构和取压方式一定时,雷诺数决定了流体的流态和空化现象,过冷度影响了空化的发生条件,粗糙度影响了流体的摩擦阻力,气相含率影响了流体的密度。

关键词：液氢多孔平衡流量计流动阻力特性空化效应

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二维材料微观摩擦学研究进展

微纳电子技术 2024年第9期61卷 1-10页

作者：赵永康王优强于童童青岛理工大学机械与汽车工程学院山东青岛266520 工业流体节能与污染控制教育部重点实验室山东青岛266520 中国科学院兰州化学物理研究所固体润滑国家重点实验室兰州730000

综述了二维材料在微观摩擦学领域的研究进展,系统介绍了二维材料的分类和制备方法以及用于微观摩擦学研究的常用设备。按照单峰接触模型和异/同质结接触模型,重点介绍了二维材料在微观摩擦学的研究现状,概括分析了二维材料的结构性质、... 详细信息

综述了二维材料在微观摩擦学领域的研究进展,系统介绍了二维材料的分类和制备方法以及用于微观摩擦学研究的常用设备。按照单峰接触模型和异/同质结接触模型,重点介绍了二维材料在微观摩擦学的研究现状,概括分析了二维材料的结构性质、针尖与样品之间的相互作用、材料与衬底之间的相互作用,以及外加电场等对微观摩擦学的影响机制。总结了基于二维材料在微观摩擦学领域的摩擦和磨损机制,包括声子作用机制、电子-声子耦合机制以及电子作用机制。基于上述机制,通过利用削弱乃至消除褶皱效应、调控电-声耦合及构建非公度接触等手段,可以实现微观尺度的超低摩擦乃至超润滑。指出了发展微观尺度超低摩擦乃至超润滑薄膜的方法及思路。最后展望了二维材料在微观摩擦学领域的未来发展方向。

关键词：二维材料微观摩擦学原子力显微镜摩擦起源磨损本质

高压下硝酸肼结构演化的中远红外光谱和第一性原理计算研究

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高压物理学报 2024年第3期38卷 103-110页

作者：曾阳阳朱刚贝王文涛白莎郑朝阳于国洋杨延强中国工程物理研究院流体物理研究所四川绵阳621999 中国科学院大连化学物理研究所辽宁大连116023 西北大学化学与材料学院陕西西安710127

对于含能材料,6 THz(200 cm^(-1))以内的晶格振动模式对外部压力变化引起的结构变化非常敏感,因此,中远红外振动光谱可作为研究含能材料高压相变的有力手段。利用基于空气等离子体产生的中远红外超宽带光谱技术,结合金刚石对顶砧,获得... 详细信息

对于含能材料,6 THz(200 cm^(-1))以内的晶格振动模式对外部压力变化引起的结构变化非常敏感,因此,中远红外振动光谱可作为研究含能材料高压相变的有力手段。利用基于空气等离子体产生的中远红外超宽带光谱技术,结合金刚石对顶砧,获得了含能材料硝酸肼的高压振动光谱。同时,采用第一性原理方法,计算了硝酸肼的晶体结构和红外光谱,在此基础上对分子间的相互作用进行了分析。综合实验和计算结果,揭示了压力作用下分子间氢键和范德瓦尔斯相互作用对材料中分子结构和堆垛变化的影响,获得了硝酸肼的相变过程。

关键词：硝酸肼中远红外光谱第一性原理计算高压相变

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Effect of Zr on phase separation,mechanical and corrosion behavior of heterogeneous CoCrFeNiZr_(x) high-etropy alloy

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Journal of Materials Science & Technology 2022年第14期109卷 76-85页

作者： Wu Qi Wenrui wang Xiao Yang Lu Xie Jiaming Zhang Dongyue Li Yong Zhang School of Mechanical engineering University of Science and Technology BeijingBeijing 100083China Key Laboratory of fluid Interaction with Material Ministry of EducationBeijing 100083China Key Laboratory of Cryogenics Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China

CoCrFeNi high entropy alloy(HEA)has attracted extensive attention due to its excellent corrosion resistance,but the low strength limits its engineering application *** order to develop CoCrFeNi based HEAs with high strength,ductility and corrosion resistance,the effects of Zr content on the microstructure,mechanical properties and corrosion resistance of heterogeneous CoCrFeNiZr_(x)(x=0,0.25,0.5 and 1)HEAs were investigated in this *** results indicate that the increase of Zr content can significantly affect the phase stability of the alloy,and promote the formation of intermetallic compounds(Ni_(7)Zr_(2)and/or Laves phase)and the transformation of solid solution from face-centered cubic(FCC)structure(x=0,0.25 and 0.5)to body-centered cubic(BCC)structure(x=1).Reasonable control of the Zr content can endow the alloy excellent comprehensive ***,for CoCrFeNiZr_(0.25) alloy,composed of FCC matrix and a small amount of Ni_(7)Zr_(2)phases,the yield strength(~655 MPa)is increased by nearly four times higher than that of Zr-free alloy,and it also has good ductility(fracture stain>50%).Meanwhile,the corrosion resistance of CoCrFeNiZr_(0.25) alloy is better than that of *** EIS results show that the addition of Zr reduces the stability of the passive film on the alloy,which can be related to the content of the beneficial oxide in the passive film and the thickness of the passive film through XPS ***,the work functions of different phases in CoCrFeNiZr_(x)alloys were obtained by firstprinciples calculations,which further confirmed the selective corrosion mechanism of the CoCrFeNiZr_(x) alloy combining the experimental results.

关键词： High-entropy alloy Microstructure Corrosion resistance First-principles Work function

LONG PULSE HIGH POWER MICROWAVE GENERATION BY COAXIAL VIRCATOR

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LONG PULSE HIGH POWER MICROWAVE GENERATION BY COAXIAL VIRCAT...

The 17th International Conference on High-Power Particle Beams

作者： Shao Hao Zhang Yongpeng Liu Guozhi Song Zhimin Zhang Yuchuan Teng Yan Zhang Ligang Northwest institute of Nuclear Technology P.O.Box 69-13 Xi’an 710024 china

＜正＞Experiment results of long pulse high power microwave （HPM） generation by coaxial vircator is *** HV generator-MC55 is rebuilt to provide the diode voltage ranging from 300kV to 500kV under 10Ωdiode impedance with lOOns pulse *** pulse coaxial vircator system is built,and a power of 570MW,S band HPM pulse with 80ns FWHA is obtained in the *** relationship between pulse shortening effect and diode gap is experimentally studied,which shows that the HPM pulsed length is in direct ratio with diode *** the optimized experimental configuration,no pulse shortening effect caused by the factor other than diode voltage fluctuation is observed, which is also in consistent with the PIC simulation results

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PULSE SHORTENING IN THE IMPROVED MAGNETICALLY INSULATED TRANSMISSION LINE OSCILLATOR

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PULSE SHORTENING IN THE IMPROVED MAGNETICALLY INSULATED TRAN...

The 17th International Conference on High-Power Particle Beams

作者： Yu-Wei Fan Hui-Huang Zhong Zhi-Qiang Li Jin-Liang Liu Jian-Hua Yang Cheng-Wei Yuan Ling Luo College of Optoelectric Science and engineering National University of Defense Technology Changsha 410073 china

＜正＞Magnetically insulated transmission line oscillator （MILO） is a crossed field device designed specifically to generate microwave power at the gigawatt level, which is a major hotspot in the field of high-power microwaves （HPM） research at *** improved MILO has been developed in our *** the improved MILO is driven by a 550kV,54kA,80ns electron beam,HPM is generated with power of 3.2 GW,frequency of about 1.76 GHz,and duration of 40 *** order to lengthen the duration of the radiated microwave pulse,a long-pulse accelerator,whose voltage is about 450 kV and impedance is about 15Ω, is employed to drive the improved *** experiments,the diode voltage is increased gradually from about 350 kV to about 460 *** the diode voltages are 375 kV,438 kV and 458 kV,the corresponding microwave power are 0.7 GW,1.8 GW and 2.3 GW,and the pulse duration are 110 ns,100 ns, and 65 ns *** is obvious that pulse shortening is observed in the *** simulation and experimental results confirm that the leading reason for pulse shortening is the remarkable voltage variation in the *** conclusion,a sufficiently flat voltage pulse is crucial to achieving a longer microwave pulse.

关键词：

AN ADVANCES IN RELATIVISTIC BWOS AT REPETITIVE RATE

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AN ADVANCES IN RELATIVISTIC BWOS AT REPETITIVE RATE

The 17th International Conference on High-Power Particle Beams

作者： Chen Changhua Liu Guozhi Huang Wenhua Shao Hao Sun Jun Xiao Renzhen Zhang Xiaowei Zhang Yuchuan Northwest institute of Nuclear Technology P.O.Box 69-13 Xi’an 710024 china

＜正＞Advances of repetitively operated relativistic backward wave oscillator （BWOs） is *** of operating stability of BWO was obtained based on our earlier BWO operating at 100 Hz repetitive rates through changing the cathode and beam *** oil- immersed graphite cathode and water-cooled beam collector were introduced to increase output stability. Experimental results indicate that BWO’s efficiency is up to the highest 33 % at optimum diode voltage,which is consistent with numerical *** BWO could stably operate at rates of 100 Hz with microwave output power of over 1 GW,and the continuous time was up to 5 seconds.

关键词： HPM backward wave oscillator repetitive rate

铝合金板阵列微结构零件电磁冲击液压成形研究

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精密成形工程 2024年第3期16卷 123-130页

作者：颜子钦赵鹏朱玉德阳光王瀚鹏徐勇崔晓辉中南大学机电工程学院长沙410083 中南大学轻合金研究院长沙410083 恩普赛技术有限公司湖北襄阳441021 中国科学院金属研究所沈阳110016

目的解决室温条件下因铝合金塑性流动不均而导致的零件开裂和尺寸偏差等问题。方法利用高速冲击提高材料成形极限以及流体均匀载荷精确控形的优势,提出了电磁冲击液压工艺并实现了铝合金阵列结构零件的成形,采用实验手段研究了放电电压... 详细信息

目的解决室温条件下因铝合金塑性流动不均而导致的零件开裂和尺寸偏差等问题。方法利用高速冲击提高材料成形极限以及流体均匀载荷精确控形的优势,提出了电磁冲击液压工艺并实现了铝合金阵列结构零件的成形,采用实验手段研究了放电电压和放电次数对零件贴模精度和厚度分布的影响。结果随着放电电压的增大,零件的成形深度增大。在单次放电8kV下,板料最大成形深度达到模具深度的97%,连续3次放电8kV后,零件通道填充率达到89.7%。建立了与物理实验模型一致的电磁-流体-结构的多物理场耦合仿真模型,发现冲击液体对板料施加的瞬态压强超过200MPa,板料最大变形速度达到40.5m/s。模拟得到的板料变形轮廓与实验结果一致,证明了多物理场耦合仿真模型的准确性。结论电磁冲击液压成形是一种新型的高速成形方法,能够实现铝合金阵列微结构零件的精确制造,为提高复杂薄壁难变形构件的成形性能和精度提供了新的技术手段。

关键词：电磁冲击液压阵列微结构高速率成形多物理场耦合仿真流固耦合

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