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Local magnetic moment oscillation around an Anderson impurity on graphene

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 192-201页

作者： Shuai Li zhen Ma Jin-Hua gao School of Science Hebei University of Science and Technology School of Electronics and Information Zhengzhou University of Light Industry School of Physics and Wuhan National High Magnetic Field Center Huazhong University of Science and Technology

We theoretically investigate the spin resolved Friedel oscillation （FO） and quasiparticle interference （QPI） in graphene induced by an Anderson *** the impurity becomes magnetic,the resulted FO becomes spin dependent,which gives rise to a local magnetic moment oscillation with an envelop decaying as r-2in real space in the doping ***,at half filling,the electron density and local magnetic moment will not oscillate but decay as *** spin resolved FO has both sublattice and spin ***,the local magnetic moment decay at half filling only occurs at one sublattice of graphene,which is quite like the phenomenon observed in the STM experiment (***ález-Herrero et al.,Science 352,437 （2016）).We further give an analytic formula about such spin dependent FO based on the stationary phase ***,we study the interference of quasiparticles around the magnetic impurity by calculating the spin dependent Fourier-transformed local density of states （FT-LDOS）.Our work gives a comprehensive understanding about the local magnetic moment oscillation around an Anderson impurity on graphene.

关键词： Friedel oscillation local magnetic moment graphene Anderson impurity

Wafer‑Scale Ag_(2)S‑Based Memristive Crossbar Arrays with Ultra‑Low Switching‑Energies Reaching Biological Synapses

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Nano-Micro Letters 2025年第3期17卷 328-339页

作者： Yuan Zhu Tomas Nyberg Leif Nyholm Daniel Primetzhofer xun Shi zhen Zhang Division of Solid‑State Electronics Department of Electrical EngineeringUppsala University75121 UppsalaSweden Department of Chemistry Uppsala UniversityUppsalaSweden Department of Physics and Astronomy Uppsala UniversityUppsalaSweden State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050People’s Republic of China

Memristive crossbar arrays(MCAs)offer parallel data storage and processing for energy-efficient neuromorphic ***,most wafer-scale MCAs that are compatible with complementary metal-oxide-semiconductor(CMOS)technology still suffer from substantially larger energy consumption than biological synapses,due to the slow kinetics of forming conductive paths inside the memristive *** we report wafer-scale Ag_(2)S-based MCAs realized using CMOS-compatible processes at temperatures below 160℃.Ag_(2)S electrolytes supply highly mobile Ag+ions,and provide the Ag/Ag_(2)S interface with low silver nucleation barrier to form silver filaments at low energy *** further enhancing Ag+migration in Ag_(2)S electrolytes via microstructure modulation,the integrated memristors exhibit a record low threshold of approximately−0.1 V,and demonstrate ultra-low switching-energies reaching femtojoule values as observed in biological *** low-temperature process also enables MCA integration on polyimide substrates for applications in flexible ***,the intrinsic nonidealities of the memristive units for deep learning can be compensated by employing an advanced training *** impressive accuracy of 92.6%in image recognition simulations is demonstrated with the MCAs after the *** demonstrated MCAs provide a promising device option for neuromorphic computing with ultra-high energy-efficiency.

关键词： Wafer-scale Ag_(2)S films Reactive sputter Silver nucleation Ag^(+)migration Energy-efficient neuromorphic computing

基于LPT近似算法的CFD并行计算网格分配算法

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工程力学 2015年第5期32卷 243-249,256页

作者：唐逸豪高振勋蒋崇文李椿萱北京航空航天大学航空科学与工程学院北京100191

针对结构网格CFD并行计算中的负载平衡问题,基于排序理论设计了LPT(Largest Processing Time)近似负载平衡算法。利用贪心策略理论对应用LPT近似算法求解负载平衡问题的可行性与局限性进行了证明与理论分析,并提出了一种LPT改进优化算... 详细信息

针对结构网格CFD并行计算中的负载平衡问题,基于排序理论设计了LPT(Largest Processing Time)近似负载平衡算法。利用贪心策略理论对应用LPT近似算法求解负载平衡问题的可行性与局限性进行了证明与理论分析,并提出了一种LPT改进优化算法。通过数值仿真考察了LPT近似算法及LPT改进优化算法的性能,结果表明LPT近似算法可应用于求解CFD并行计算的负载平衡问题,而该文提出的LPT改进优化算法比LPT近似算法在负载分配上更为均衡。

关键词：并行计算负载平衡排序理论贪心策略 LPT近似算法

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车厢间风挡形式对高速列车气动性能的影响

铁道学报 2012年第11期34卷 29-35页

作者：杨加寿蒋崇文高振勋吕宇超张劲柏李椿萱北京航空航天大学国家计算流体力学实验室北京100191

以3节车厢组成的CRH380型列车简化模型为基础,在速度分别为360、420、500km/h的条件下,研究车厢间7种风挡形式对各车厢和车厢连接处气动性能的影响。对比分析结果表明:车厢间风挡形式对车厢的压差阻力和黏性阻力影响不大;上下风挡比侧... 详细信息

以3节车厢组成的CRH380型列车简化模型为基础,在速度分别为360、420、500km/h的条件下,研究车厢间7种风挡形式对各车厢和车厢连接处气动性能的影响。对比分析结果表明:车厢间风挡形式对车厢的压差阻力和黏性阻力影响不大;上下风挡比侧风挡对车厢的升力影响更大;车厢间采用全风挡与采用典型风挡相比,前者车厢连接处的气动阻力约为后者的7%,而无风挡的车厢连接处的气动阻力约为其50%;若车厢间采用上下和两侧闭式风挡,则车厢连接处的压差阻力约为典型风挡的30%。综合考虑气动性能和工程易实现性,采用上下和两侧闭式风挡形式更适用于高速列车。

关键词：高速列车空气动力学车厢间缝隙风挡数值模拟

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飞行器气动设计教学的思考与实践

教育教学论坛 2017年第8期 210-211页

作者：吴宗成邹辉高振勋北京航空航天大学航空科学与工程学院北京100191

飞行器设计空气动力学是重要的研究生专业课,本课程综合性强,涉及面广,将经典理论和飞行器前沿设计技术紧密结合,直接面向飞行器设计工程应用部门,本文重点讨论了课程的特点、课程内容的组织实施、教学方法的综合应用等方面。

关键词：气动设计教学

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基于神经网络的翼型气动力计算和反设计方法

气体物理 2018年第5期3卷 41-47页

作者：刘凌君周越高振勋北京航空航天大学航空科学与工程学院北京100191

开展了机器学习在翼型气动力计算和反设计方法中的应用研究,实现了在更大翼型空间范围内,人工神经网络的训练和优化,建立了翼型气动力计算模型,和给定目标压力分布的翼型反设计优化模型.作为机器学习领域兴起的研究热点,人工神经网络的... 详细信息

开展了机器学习在翼型气动力计算和反设计方法中的应用研究,实现了在更大翼型空间范围内,人工神经网络的训练和优化,建立了翼型气动力计算模型,和给定目标压力分布的翼型反设计优化模型.作为机器学习领域兴起的研究热点,人工神经网络的研究工作不断深入,有研究者尝试将其应用于流体力学的学科范畴内.文章实现人工神经网络在翼型计算领域中应用的方法如下:首先通过Parsec参数化方法,围绕基准翼型构造了一定翼型空间范围的翼型库,利用XFOIL进行数值模拟,搭建了和翼型库具有一一映射关系的流场信息库.通过训练和优化神经网络,实现了基于此模型的快速、高可信度的翼型气动力预测,以及新型的翼型优化设计方法.通过自动化编程实现样本库的批量生成,实现了不同翼型空间的样本量下,神经网络的训练和优化过程.实验结果表明,在机器学习领域中,基于神经网络的翼型反设计模型的精确性高度依赖于训练样本量的大小和覆盖范围.

关键词：神经网络气动力翼型反设计 PARSEC参数法计算流体力学

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辐射平衡壁温下有限催化模型数值模拟

气体物理 2021年第5期6卷 1-11页

作者：莫凡王锁柱高振勋北京航空航天大学航空科学与工程学院北京100191 北京航天长征飞行器研究所北京100076

文章发展了高超声速飞行器辐射平衡壁温下有限催化的数值方法,将数值模拟结果与基于返回舱外形的风洞实验数据进行了对比,并进一步针对典型高超声速飞行器钝双锥研究了辐射平衡壁温下有限催化对气动热环境的影响规律.针对返回舱外形的... 详细信息

文章发展了高超声速飞行器辐射平衡壁温下有限催化的数值方法,将数值模拟结果与基于返回舱外形的风洞实验数据进行了对比,并进一步针对典型高超声速飞行器钝双锥研究了辐射平衡壁温下有限催化对气动热环境的影响规律.针对返回舱外形的数值实验表明,完全催化与完全非催化边界条件下壁面热流密度均与风洞实验结果偏差较大,而采用合适的有限催化模型获得的壁面热流密度与风洞实验结果符合良好.针对典型高超声速飞行器钝双锥的研究表明,在辐射平衡温度边界条件下驻点附近氧原子的催化复合系数约为0.17,氮原子的催化复合系数约为0.026,大面积区则分别降为0.0053和0.01.在驻点热流密度方面,完全催化的壁面热流峰值比有限催化高约21%,而完全非催化的壁面热流峰值比有限催化低约29%.

关键词：高超声速化学非平衡有限催化辐射平衡

Jet Vectoring Control Using a Novel Synthetic Jet Actuator

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Chinese Journal of Aeronautics 2007年第3期20卷 193-201页

作者： LUO zhen-bing XIA Zhi-xun XIE Yong-gao College of Aerospace and Materials Engineering National University of Defense Technology Changsha 410073 China

A primary air jet vectoring control system with a novel synthetic jet actuator （SJA） is presented and simulated numerically. The results show that, in comparison with an existing traditional synthetic jet actuator, which is able to perform the duty of either ＂push＂ or ＂pull＂, one novel synthetic jet actuator can fulfill both ＂push＂ and ＂pull＂ functions to vector the primary jet by shifting a slide block inside it. Therefore, because the new actuator possesses greater efficiency, it has potentiality to replace the existing one in various appli- cations, such as thrust vectoring and the reduction of thermal signature. Moreover, as the novel actuator can fulfill those functions that the existing one can not, it may well be expected to popularize it into more flow control systems.

关键词： jet vectoring control synthetic jet actuator slide block flow control

Experimental study on compaction-induced anisotropic mechanical property of rockfill material

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Frontiers of Structural and Civil Engineering 2021年第1期15卷 109-123页

作者： Xiangtao ZHANG Yizhao gao Yuan WANG Yu-zhen YU xun SUN State Key Laboratory of Hydroscience and Engineering Department of Hydraulic EngineeringTsinghua UniversityBeijing 100084China

The anisotropy of rockfill materials has a significant influence on the performance of engineering ***,relevant research data are very limited,because of the difficulty with preparing specimens with different inclination angles using traditional ***,the anisotropy test of rockfill materials is complex and complicated,especially for triaxial tests,in which the major principal stress plane intersects with the compaction plane at different *** this study,the geometric characteristics of a typical particle fraction consisting of a specific rockfill material were statistically investigated,and the distribution characteristics of particle orientation in specimens prepared via different compaction methods were *** high-density rockfill materials,a set of specimen preparation devices for inclined compaction planes was developed,and a series of conventional triaxial compression tests with different principal stress direction angles were *** results reveal that the principal stress direction angle has a significant effect on the modulus,shear strength,and dilatancy of the compacted rockfill *** of the relationship between the principal stress direction angles,change in the stress state,and change in the corresponding dominant shear plane shows that the angle between the compacted surface and dominant shear plane is closely related to interlocking resistance associated with the particle *** addition,different principal stress direction angles can change the extent of the particle interlocking effect,causing the specimen to exhibit different degrees of anisotropy.

关键词： rockfill inclination of specimen preparation anisotropy mechanical property mechanism