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Probing a Dissipative Phase Transition with a Trapped Ion through Reservoir Engineering

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Chinese Phy.ics Letters 2022年第2期39卷 10-14页

作者： M.-L.Cai Z.-D.Liu y.Jiang y.-k.wu Q.-X.Mei W.-D.Zhao L.He X.Zhang Z.-C.Zhou L.-M.Duan Center for Quantum Information Institute for Interdisciplinary Information SciencesTsinghua UniversityBeijing 100084China Department of Phy.ics Renmin UniversityBeijing 100084China Beijing Academy.of Quantum Information Sciences Beijing 100193China

Dissipation is often considered as a detrimental effect in quantum sy.tems for unitary.quantum ***,it has been shown that suitable dissipation can be useful resources in both quantum information and quantum ***,we propose and experimentally.simulate a dissipative phase transition(DPT)model using a single trapped ion with an engineered *** show that the ion’s spatial oscillation mode reaches a steady.state after the alternating application of unitary.evolution under a quantum Rabi model Hamiltonian and sideband cooling of the *** average phonon number of the oscillation mode is used as the order parameter to provide evidence for the *** work highlights the suitability.of trapped ions for simulating open quantum sy.tems and shall facilitate further investigations of DPT with various dissipation terms.

关键词： quantum unitary oscillation

SUPERPLASTICITy.IN SiC_w/Zk60 COMPOSITE

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Acta Metallurgica Sinica(English Letters) 2003年第3期16卷 217-220页

作者： F.y.n k.wu M.Zhao School of Muterials Science and Engineering Harbin Institute of Technology Harbin 150001ChinaSchool of Muterials Science and EngineeringHarbin Institute of Technology Harbin 150001ChinaSchool of Muterials Science and EngineeringHarbin Institute of Technology Harbin 150001China

The superplastic deformation behavior of SiCw/Zk60 composite was investigated at temperatures ranging from 573k to 723k and at initial strain rates ranging from 8.3x10-4s-1 to 8.3x10-2s-1. A maximum elongation of 200% with a m-value of 0.35 was obtained at 613k and a initial strain rate of 1.67x 10-2s-1. The apparent activation energy.(98kJ/mol) approximates that for grain boundary.diffusion (92kJ/mol) in magnesium. It is proposed that the dominant mechanism of superplastic deformation in the present composite is grain boundary.sliding accommodated by.diffusional transport, besides, interfacial sliding play. an important role in the superplastic deformation.

关键词： magnesium matrix composite superplasticity apparent activation energy

Processing, Microstructure and Mechanical Properties of Ti6Al4V Particles-Reinforced Mg Matrix Composites

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Acta Metallurgica Sinica(English Letters) 2016年第10期29卷 940-950页

作者： X.M.Wang X.J.Wang X.S.Hu k.wu M.y.Zheng School of Materials Science and Engineering Harbin Institute of Technology

Novel Ti6Al4V particles-reinforced AZ91 Mg matrix composites were successfully.fabricated by.stir casting method. The stirring time in semisolid condition directly.affected the particle distribution and the quality.of the ingots. Furthermore, the optimal speed of the heating and the liquid stirring could overcome particle settlement caused by.the density.difference between the matrix and the particles. Ti6Al4V particles distributed uniformly.in the composites with different particle contents. The average grain size decreased with the increase in the particle contents. The Ti6A14V particles bonded pretty.well with the alloy.matrix. In addition, there were some interfacial reactions in the composites. There were rod-like A13Ti phases at the interface. The precipitates extended from the particle surface to the matrix, and they.might improve the interfacial bonding strength. The ultimate tensile strength, y.eld strength and elastic modulus were enhanced as the particle contents increased, and the elongation was much better than that of the same matrix material reinforced with SiC particles. Thus, the novel composites exhibit better comprehensive mechanical properties.

关键词： Magnesium matrix composites Ti6Al4V particles Stir casting Microstructure Mechanicalproperties

Magnesium matrix composite reinforced by.nanoparticles-A review

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Journal of Magnesium and Alloy. 2021年第1期9卷 57-77页

作者： k.B.Nie X.J.Wang k.k.Deng X.S.Hu k.wu State key.Laboratory.of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China

Significant progress has been made in magnesium-based composites during recent decades,especially.for the appearance of magnesium matrix composite reinforced by.*** nanoparticles added not only.exhibit a good strengthening effect,but also maintain the initial toughness of the matrix,effectively.balancing the contradiction between the strength and plasticity.in the traditional magnesium matrix *** magnesium matrix nanocomposites with excellent mechanical properties have pushed the development of magnesium matrix composites to a new ***,it is very.difficult to disperse the nanoparticles in metal melt especially.in magnesium melt which is different from other metal melts and dangerous during the cast *** means that the preparation of magnesium matrix nanocomposite is extremely.***,the magnesium matrix nanocomposites possess a distinctive characteristic in deformation behavior,strengthening and toughening mechanism due to their special size effect of ***,this review will focus on the new preparation technologies,deformation behavior,mechanical properties and strengthening and toughening *** potential applications,development trends and future research ideas of magnesium matrix nanocomposite are also prospected.©2020 Published by.Elsevier *** behalf of Chongqing University.

关键词： Magnesium matrix nanocomposite Microstructure Mechanical properties Strengthening mechanism

An insight into Mg alloy.ng effects on Cu thin films:microstructural evolution and mechanical behavior

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Journal of Materials Science & Technology 2020年第22期54卷 101-112页

作者： G.y.Li L.F.Cao J.y.Zhang X.G.Li y.Q.Wang k.wu G.Liu J.Sun State key.Laboratory.for Mechanical Behavior of Materials Xi'an Jiaotong UniversityXi'an710049China International Joint Laboratory.for Light Alloy.(Ministry.of Education) College of Materials Science and EngineeringChongqing UniversityChongqing400044China Electron Microscopy.Center of Chongqing University Chongqing UniversityChongqing400044China

How to design ultra-strong,light-weight Cu alloy. is a long-term pursuit in materials community.which is technically.superior and cost-effective for their promising energy.saving *** this work,we prepared Cu-Mg alloy.d thin films to study.light element Mg alloy.ng effects on the microstructure,hardness and strain rate sensitivity.SRS) of nanocry.talline Cu thin *** the studied Mg concentrationrange spanning from 0 at.% to 16.8 at.%,both the grain size and the twin spacing decrease monotonously.with increasing Mg composition while Cu-2.8 at.% Mg sample has the highest twin fraction of ~75%.A combined strengthening model was employ.d to quantify.the Mg concentration-dependent hardness of nanotwinned(NT) Cu-Mg thin films,in which the grain/twin boundary.facilitates strengthening while the solute Mg atoms induce *** the constant rate of loading tests and the nanoindentation creep tests uncover that compared with pure Cu samples,the NT Cu-Mg thin films manifest much lower SRS,particularly.in the creep tests,owing to the activation of dy.amic strain aging effects.

关键词： Cu-Mg thin films Microstructure evolution Creep tests Hardness Strain rate sensitivity

Unusual He-ion irradiation strengthening and inverse lay.r thickness-dependent strain rate sensitivity.in transformable high-entropy.alloy.metal nanolaminates:A comparison of Fe_(50)Mn_(30)Co_(10)Cr_(10)/Cu vs Fe_(50)Mn_(30)Co_(10)Ni_(10)/Cu

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Journal of Materials Science & Technology 2022年第21期116卷 199-213页

作者： y.F.Zhao H.H.Chen D.D.Zhang J.y.Zhang y.Q.Wang k.wu G.Liu J.Sun State key.Laboratory.for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China

In this work,we prepare transformable HEA/Cu nanolaminates(NLs)with equal individual lay.r thick-ness(h)by.the magnetron sputtering technique,i.e.,Fe_(50)Mn_(30)Co_(10)Cr_(10)/Cu and Fe_(50)Mn_(30)Co_(10)Ni_(10)/Cu,and comparatively.study.He-ion irradiation effects on their microstructure and mechanical *** ap-pears that the as-deposited HEA/Cu NLs manifest two size h-dependent hardness regimes(i.e.,increased hardness at small h and hardness plateau at large h),while the He-implanted ones exhibit monotonically.increased *** to the fashion that smaller h renders less irradiation hardening in bimetal NLs,the Fe_(50)Mn_(30)Co_(10)Cr_(10)/Cu NLs manifest the trend that smaller h leads to greater irradiation *** contrast,the Fe_(50)Mn_(30)Co_(10)Ni_(10)/Cu NLs exhibit the maximum irradiation hardening at a critical h=50 *** this critical size,smaller h results in lower radiation hardening(similar to bimetal NLs),while above this size,smaller h results in greater radiation hardening(similar to Fe_(50)Mn_(30)Co_(10)Cr_(10)/Cu NLs).Moreover,these transformable HEA/Cu NLs display.inverse h-dependent strain rate sensitivity.SRS m)before and after He-ion ***,compared with as-deposited samples,the irradi-ated Fe_(50)Mn_(30)Co_(10)Cr_(10)/Cu NLs display.reduced SRS,while the irradiated Fe_(50)Mn_(30)Co_(10)Ni_(10)/Cu NLs dis-play.enhanced *** unusual size-dependent irradiation strengthening and inverse h effect on SRS in irradiated samples were rationalized by.considering the blocking effects of He bubbles on dislocation nucleation and motion,i.e.,dislocations shearing or by.assing He bubbles.

关键词： High entropy.alloy.metal nanolaminates Interfaces Irradiation hardening Strain rate sensitivity Size effects

Tuning the interfacial reaction environment via pH-dependent and induced ions to understand C–N bonds coupling performance in NO3- integrated CO2 reduction to carbon and nitrogen compounds over dual Cu-based N-doped carbon cataly.t

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Journal of Energy.Chemistry 2025年第1期100卷 273-285页

作者： Tianhang Zhou Chen Shen Zhenghao wu Xingy.ng Lan y. Xiao College of Carbon Neutrality.Future Technology State Key Laboratory of Heavy Oil Processing China University of Petroleum (Beijing) Institute of Materials Science TU Darmstadt Department of Chemistry Xi'an Jiaotong-Liverpool University Department of Mechanical and Mechatronics Engineering and Waterloo Institute of Nanotechnology University of Waterloo Waterloo

Dual atomic cataly.ts （DAC）,particularly.copper （Cu2）-based nitrogen （N） doped graphene,show great potential to effectively.convert CO2and nitrate （NO3-） into important industrial chemicals such as ethy.ene,gly.ol,acetamide,and urea through an efficient cataly.ical process that involves C–C and C–N ***,the origin of the coupling activity.remained unclear,which substantially.hinders the rational design of Cu-based cataly.ts for the N-integrated CO2reduction reaction （CO2RR）.To address this challenge,this work performed advanced density.functional theory.calculations incorporating explicit solvation based on a Cu2-based N-doped carbon (Cu2N6C10) cataly.t for *** calculations are aimed to gain insight into the reaction mechanisms for the sy.thesis of ethy.ene,acetamide,and urea via coupling in the interfacial reaction *** to the sluggishness of CO2,the formation of a solvation electric lay.r by.anions （F-,Cl-,Br-,and I-） and cations (Na+,Mg2+,k+,and Ca2+) leads to electron transfer towards the Cu *** process significantly.accelerates the reduction of *** results reveal that*CO intermediates play.a pivotal role in N-integrated ***,the Cu2-based N-doped carbon cataly.t examined in this study.has demonstrated the most potential for C–N coupling to *** findings reveal that through the process of a condensation reaction between*CO and NH2OH for urea sy.thesis,*NO3-is reduced to*NH3,and*CO2to*CCO at dual Cu atom *** dual-site reduction facilitates the sy.thesis of acetamide through a nucleophilic reaction between NH3and the ketene ***,we found that the I-and Mg2+ions,influenced by.pH,were highly.effective for acetamide and ammonia sy.thesis,except when F-and Ca2+were ***,the mechanisms of C–N bond formation were investigated via ab-initio molecular dy.amics simulations,and we found that adjusting the micro-environment can change the dominant side reaction,shift

关键词： Condensation reactions

Secure beamforming and deploy.ent design for rate-splitting multiple access-based UAV communications

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Science China(Information Sciences) 2025年第1期68卷 342-356页

作者： Bing WANG Xiaofeng TAO Shujun HAN Huici wu kai y.NG Zhu HAN National Engineering Research Center of Mobile Network Technologies Beijing University of Posts and Telecommunications Peng Cheng Laboratory Department of Electrical and Computer Engineering University of Houston

Rate-splitting multiple access(RSMA) has recently.gained attention as a potential robust multiple access(MA)scheme for upcoming wireless networks. Given its ability.to efficiently.utilize wireless resources and design interference management strategies, it can be applied to unmanned aerial vehicle(UAV) networks to provide convenient services for large-scale access ground users. However, due to the line-of-sight(LoS) broadcast nature of UAV transmission, information is susceptible to eavesdropping in RSMA-based UAV networks. Moreover, the superposition of signals at the receiver in such networks becomes complicated. To cope with the challenge, we propose a two-user multi-input single-output(MISO) RSMA-based UAV secure transmission framework in downlink communication networks. In a passive eavesdropping scenario, our goal is to maximize the sum secrecy.rate by.optimizing the transmit beamforming and deploy.ent location of the UAV-base station(UAV-BS),while considering quality.of-service(QoS) constraints, maximum transmit power, and flight space limitations. To address the non-convexity.of the proposed problem, the optimization problem is first decoupled into two subproblems. Then, the successive convex approximation(SCA) method is employ.d to solve each subproblem using different propositions. In addition, an alternating optimization(AO)-based location RSMA(L-RSMA) beamforming algorithm is developed to implement joint optimization to obtain the suboptimal solution. Numerical results demonstrate that(1) the proposed L-RSMA scheme y.elds a28.97% higher sum secrecy.rate than the baseline L-space division multiple access(SDMA) scheme;(2) the proposed L-RSMA scheme improves the security.performance by.42.61% compared to the L-non-orthogonal multiple access(NOMA) scheme.

关键词： rate-splitting multiple access UAV communication precoding optimization deploy.ent location phy.ical lay.r security

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When AI meets sustainable 6G

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Science China(Information Sciences) 2025年第1期68卷 4-22页

作者： Xiaohu y.U y.ngming HUANG Cheng ZHANG Jiaheng WANG Hao y.N Hequan wu National Mobile Communications Research Laboratory Southeast University Purple Mountain Laboratories Chinese Academy.of Military.Science China Information Communication Technologies Group

Sixth-generation(6G) networks are anticipated to achieve transformative advancements, characterized by.extreme connectivity. deep integration with artificial intelligence(AI) and sensing, and airground integration. The evolution of 6G exhibits two major trends: ubiquitous intelligence and sustainability. The former aims to embed state-of-the-art AI technology.into the 6G network, from the phy.ical lay.rs to applications, while the latter emphasizes reducing energy.consumption while enhancing network performance to address environmental concerns. Despite the amazing progress in recent y.ars, AI advancements come with substantial increases in data and computational overhead, posing critical challenges for integrating AI into sustainable 6G networks. First, high energy.consumption from large datasets and heavy.eight AI models contradicts6G's green goals. Second, the precise collection of large datasets, message delivery.latency. and inference delay. in AI models pose challenges for real-time tasks in 6G. Third, the uninterpretability.and unpredictability.of AI models complicate meeting the stringent requirements for controllable transmission in dy.amic wireless environments. Addressing these challenges and achieving sustainable 6G with ubiquitous intelligence calls for a revolutionary.design of 6G architecture and AI frameworks. To this end, this paper introduces a novel and practical methodology.for green, real-time, and controllable 6G native intelligence,starting with knowledge graph(kG) analy.is to extract small but critical datasets, followed by.the development of distributed lightweight AI models, and the use of digital twins(DTs) to create precise replicas of phy.ical 6G networks. This leads to a pervasive multi-level(PML)-AI framework supported by.a task-centric, three-lay.r 6G architecture. The AI framework operates through non-real-time and real-time cy.les, leveraging three key.technologies: wireless data kGs for efficient data management,lightweight AI mode

关键词： artificial intelligence sustainable 6G green real-time controllable