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Hygrothermal effect on high-velocity impact resistance of woven composites

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Defence Technology（防务技术） 2022年第5期18卷 823-833页

作者： Xiao-chen Yang nan jia School of Urban Construction Eastern Liaoning UniversityWenhua 325Dandong118003China College of Safety Science and Engineering Liaoning Technical UniversityFuxin123000China China Coal Technology&Engineering Group Shenyang Research Institute Fushun113122China State Key Laboratory of Coal Mine Safety Technology Fushun113122China

The woven glass fiber reinforced composites(GFRP)subjected to high-speed impact is investigated to identify the hygrothermal aging effect on the impact resistance.Both the hygrothermal aged and unaged glass/epoxy laminates are subjected to different impact velocities,which is confirmed as a sensitive factor for the failure modes and mechanisms.The results show the hygrothermal aging effect decreases the ballistic limit by 14.9%,but the influence on ballistic performance is limited within the impact velocity closed to the ballistic limit.The failure modes and energy dissipation mechanisms are confirmed to be slightly influenced by the hygrothermal aging effect.The hygrothermal aging effect induced localization of structural deformation and degradation of mechanical properties are the main reasons for the composite undergoing the same failure modes at smaller impact velocities.Based on the energy absorption mechanisms,analytical expressions predict the ballistic limit and energy absorption to reasonable accuracy,the underestimated total energy absorption results in a relatively poor agreement between the measured and predicted energy absorption efficiency.

关键词： Hygrothermal aging effect Woven glass/epoxy composite Impact resistance Dynamic failure Energy absorption

Constellation shaping optimization for nonlinearity mitigation in CAP UVLC system

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Science China(Information Sciences) 2023年第9期66卷 274-290页

作者： Junlian jia Junwen ZHANG nan CHI Key Laboratory for Information Science of Electromagnetic Waves(MoE) Fudan University Shanghai Engineering Research Center of Low-Earth-Orbit Satellite Communication and Applications Shanghai Collaborative Innovation Center of Low-Earth-Orbit Satellite Communication Technology Peng Cheng Laboratory

In the sixth-generation communication(6G), wireless communication will cover not only conventional air links but also underwater links. Underwater visible light communication(UVLC) is an expected technique that achieves a high data rate. However, UVLC systems suffer from severe nonlinear distortions for the high-power transmitting, thus nonlinear compensation is vital to the system. Carrier-less amplitude and phase(CAP) modulation is a promising modulation, especially for the scenes with high nonlinear effects.In this paper, for the first time, we proposed a constellation optimization method for the UVLC system supporting the native artificial intelligence in 6G. The proposed framework, based on the complete process of the CAP modulation and demodulation, fulfills an end-to-end learning scheme with a neural network at the transmitter side and the conventional demodulation processes at the receiver side. A loss function is further designed to support the training without needing a fixed signal-to-noise ratio(SNR). The proposed framework is simulated and then tested in an experiment. In a 1.2-meter nonlinear UVLC channel, compared with 1.5 Gbit/s supported by the conventional grid encoding, the proposed method brings an extra 200 Mbit/s data rate.

关键词： underwater visible light communication nonlinearity compensation constellation optimization

Heterogeneity of the tumor immune microenvironment and clinical interventions

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Frontiers of Medicine 2023年第4期17卷 617-648页

作者： Zheng Jin Qin Zhou jia-nan Cheng Qingzhu jia Bo Zhu Department of Oncology Xinqiao HospitalArmy Medical UniversityChongqing 400037China Key Laboratory of Tumor Immunotherapy Chongqing 400037China Research Institute GloriousMed Clinical Laboratory(Shanghai)Co.Ltd.Shanghai 201318China Institute of Life Sciences Chongqing Medical UniversityChongqing 400016China School of Pharmacy and Bioengineering Chongqing University of TechnologyChongqing 400054China

The tumor immune microenvironment(TIME)is broadly composed of various immune cells,and its heterogeneity is characterized by both immune cells and stromal cells.During the course of tumor formation and progression and anti-tumor treatment,the composition of the TIME becomes heterogeneous.Such immunological heterogeneity is not only present between populations but also exists on temporal and spatial scales.Owing to the existence of TIME,clinical outcomes can differ when a similar treatment strategy is provided to patients.Therefore,a comprehensive assessment of TIME heterogeneity is essential for developing precise and effective therapies.Facilitated by advanced technologies,it is possible to understand the complexity and diversity of the TIME and its influence on therapy responses.In this review,we discuss the potential reasons for TIME heterogeneity and the current approaches used to explore it.We also summarize clinical intervention strategies based on associated mechanisms or targets to control immunological heterogeneity.

关键词： tumor immune heterogeneity clinical intervention tumor microenvironment

A numerical study of hydrodynamic influence on collision of brash ice with a structural plate

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Journal of Hydrodynamics 2022年第1期34卷 43-51页

作者： Li Zhou Zhi Zong jia-nan Li School of Naval Architecture Dalian University of TechnologyDalian116024China Tianjin Branch HuaDian Heavy Industries Co.Ltd Tianjin300010China

The ice-structure collision is a transient process, which is further complicated by the presence of the water. It remains unclear how important the hydrodynamic influences are during the collision. This problem is partially investigated in this paper using numerical methods. To simplify the problem as much as possible without loss of generality, a short ice cylinder of circular section is assumed to collide with a vertical large structure plate under a variety of collision scenarios. Among them the most important cases are: (1) the rigid ice cylinder collision with the rigid or elastic structural plate at different collision velocities, (2) the elastic ice cylinder collision with the rigid or elastic structural plate at different collision velocities and (3) the elastoplastic ice cylinder collision with the rigid or elastic structural plate at different collision velocities. The numerical results show that: (1) the hydrodynamic influences are negligible in the first case, (2) the hydrodynamic influences in the second and third cases are not negligible, and become very significant in the third case. The influences are numerically estimated to be in the range of 20%–60% in terms of the momentum change. If the ice response is approximately decomposed into the rigid-body motions and the deformation modes at the instant of the collision with the structure, the previous conclusions show that the hydrodynamic influences on the rigid-body motions of the ice are negligible, but those on the elastic and elastoplastic modes of the ice are significant. Comparison with the case of a submerged ice cylinder (although not a practical case) reveals that the hydrodynamic influences are small in the first case due to the fact that the energy loss is used to produce the water splash and the cavity behind the ice cylinder. Through this study we come into the conclusion that the hydrodynamic influences are not important for the rigid-body motions, but important for the elastic or elastoplastic modes.

关键词： Ice-structure collision hydrodynamic influence numerical rigid mode elastic mode

Dependence of Estimating Whitecap Coverage on Currents and Swells

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Journal of Ocean University of China 2021年第3期20卷 512-520页

作者： LIU Min YANG Bailin JIA Nan ZOU Zhongshui Ocean College Hebei Agriculture UniversityQinhuangdao 066000China School of Resources and Materials Northeastern University at QinhuangdaoQinhuangdao 066004China PLA Information Engineering University Zhengzhou 450001China School of Marine Science Sun Yat-Sen UniversityZhuhai 519082China

The shipboard measurements of whitecap coverage(W)and the meteorological and oceanographic information from two cruises in the South China Sea and Western Pacific are explored for estimating W.This study aims at evaluating how to im-prove the parameterizations of W while considering the effects of currents and swells on wave breaking.Currents indeed affect W in a way that winds with following currents can decrease W,whereas winds with opposing currents can increase W.Then,10-m wind speed over sea surface(U_(10))is calibrated by subtracting the current velocity from U_(10) when the propagating directions of winds and currents are aligned.By contrast,when the direction is opposite,U_(10) is calibrated by adding the parallel velocity com-ponent of the opposing current to U_(10).The power fits of W dependence on the U_(10)-related parameters of U_(10),friction velocity,wind sea Reynolds number in terms of this calibrated-U_(10) obtain better results than those directly fitted to U_(10).Different from the effect of currents on W,wind blowing along the crest line of swells may contribute to the increase in W.The conclusions suggest that U_(10) should be calibrated first before parameterizing W in areas with a strong current or some swell-dominant areas.

关键词： whitecap coverage currents friction velocity wind sea Reynolds number swells

Universal dynamic scaling and Contact dynamics in quenched quantum gases

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Frontiers of physics 2024年第2期19卷 213-220页

作者： jia-nan Cui Zhengqiang Zhou Mingyuan Sun School of Science Beijing University of Posts and TelecommunicationsBeijing 100876China State Key Lab of Information Photonics and Optical Communications Beijing University of Posts and TelecommunicationsBeijing 100876China

Recently universal dynamic scaling is observed in several systems,which exhibit a spatiotemporal self-similar scaling behavior,analogous to the spatial scaling near phase transition.The latter one arises from the emergent continuous scaling symmetry.Motivated by this,we investigate the possible relation between the scaling dynamics and the continuous scaling symmetry in this paper.We derive a theorem that the scaling invariance of the quenched Hamiltonian and the initial density matrix can lead to the universal dynamic scaling.It is further demonstrated both in a two-body system analytically and in a many-body system numerically.For the latter one,we calculate the dynamics of quantum gases quenched from the zero interaction to a finite interaction via the non-equilibrium high-temperature virial expansion.A dynamic scaling of the momentum distribution appears in certain momentum-time windows at unitarity as well as in the weak interacting limit.Remarkably,this universal scaling dynamics persists approximately with smaller scaling exponents even if the scaling symmetry is fairly broken.Our findings may offer a new perspective to interpret the related experiments.We also study the Contact dynamics in the BEC−BCS crossover.Surprisingly,the half-way time displays a maximum near unitarity while some damping oscillations occur on the BEC side due to the dimer state,which can be used to detect possible two-body bound states in experiments.

关键词： dynamic scaling Contact dynamics quantum gases cold atom quench dynamics virial expansion continuous scaling symmetry

Remarks on convexity estimates for solutions of the torsion problem

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Science China Mathematics 2023年第5期66卷 1003-1020页

作者： Xiaohan jia Xi-nan Ma Shujun Shi School of Mathematical Sciences Xiamen UniversityXiamen 361005China School of Mathematical Sciences University of Science and Technology of ChinaHefei 230026China School of Mathematical Sciences Harbin Normal UniversityHarbin 150025China

In this paper,for the solution of the torsion problem about the equation Δu=-2 with homogeneous Dirichlet boundary conditions in a bounded convex domain in Rn,we find a superharmonic function which implies the strict concavity of u ^(1/2) and give some convexity estimates.It is a generalization of Makar-Limanov’s result(Makar-Limanov(1971))and Ma-Shi-Ye’s result(Ma et al.(2012)).

关键词： convexity estimate superharmonicity maximum principle torsion problem

Psychological interventions for depression in children and adolescents:A bibliometric analysis

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World Journal of Psychiatry 2024年第3期14卷 467-483页

作者： nan Wang jia-Qi Kong nan Bai Hui-Yue Zhang Min Yin School of Nursing Lanzhou UniversityLanzhou 730000Gansu ProvinceChina

BACKGROUND Depression has gradually become a common psychological disorder among children and adolescents.Depression in children and adolescents affects their physical and mental development.Psychotherapy is considered to be one of the main treatment options for depressed children and adolescents.However,our understanding of the global performance and progress of psychological interventions for depression in children and adolescents(PIDCA)research is limited.AIM To identify collaborative research networks in this field and explore the current research status and hotspots through bibliometrics.METHODS Articles and reviews related to PIDCA from January 2010 to April 2023 were identified from the Web of Science Core Collection database.The Charticulator website,CiteSpace and VOSviewer software were used to visualize the trends in publications and citations,the collaborative research networks(countries,institutions,and authors),and the current research status and hotspots.RESULTS Until April 16,2023,1482 publications were identified.The number of documents published each year and citations had increased rapidly in this field.The United States had the highest productivity in this field.The most prolific institution was the University of London.Pim Cuijpers was the most prolific author.In the context of research related to PIDCA,both reference co-citation analysis and keywords co-occurrence analysis identified 10 research hotspots,including thirdwave cognitive behavior therapy,short-term psychoanalytic psychotherapy,cognitive behavioral analysis system of psychotherapy,family element in psychotherapy,modular treatment,mobile-health,emotion-regulation-based transdiagnostic intervention program,dementia risk in later life,predictors of the efficacy of psychological intervention,and risks of psychological intervention.CONCLUSION This bibliometric study provides a comprehensive overview of PIDCA from 2010 to present.Psychological intervention characterized as psychological-process-focused,short,family-involved,modular,inte

关键词： Child Adolescent Depression Psychological intervention Bibliometrics

Energy efficient data collection in UAV-assisted Internet of things:trajectory planning and aerodynamic-based attitude control

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The Journal of China Universities of Posts and Telecommunications 2022年第2期29卷 97-107页

作者： Wang Shiyu Chen Hao Hu nan jia Zekun School of Information and Communication Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China Science and Technology on Communication Networks Laboratory The 54th Research Institute of CETCShijiazhuang 050091China

Due to its inherent characteristics of flexible mobility,unmanned aerial vehicle(UAV) is exploited as a cost-efficient mobile platform to assist remote data collection in the 5 th generation or beyond the 5 th generation(5 G/B5 G) wireless systems.Compared with static terrestrial base stations,the line-of-sight(LoS) link between UAVs and ground nodes are stronger due to their flexibility in three-dimensional(3 D) space.Due to the fact that flexible mobility of UAVs requires high propulsion power,the limited on-board energy constrains the performance of UAV-assisted data collection.It is worth noting that UAVs can be categorized into rotary-wing UAVs and fixed-wing UAVs,either has its own characteristics in propulsion energy consumption.In this article,a comprehensive review of state-of-art studies on trajectory design schemes for rotary-wing UAVs,as well as aerodynamic-aware attitude control strategies for fixed-wing UAVs was provided.Then,two case studies for energy-efficient data collection using rotary-wing UAVs and fixed-wing UAVs were presented,respectively.More specifically,an age-energy aware data collection scheme was demonstrated for rotary-wing UAVs to optimize the timeliness of collected data.Moreover,an aerodynamic-aware attitude control strategy for fixed-wing UAVs was also demonstrated under data collection requirements.

关键词： unmanned aerial vehicle(UAV) path planning wireless communication network data collection