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A unified theory for gas dynamics and aeroacoustics in viscous compressible *** *** fluid

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Acta Mechanica Sinica 2022年第12期38卷 65-79,I0002页

作者： Feng Mao Linlin Kang Luoqin Liu Jiezhi wu State Key Laboratory for Turbulence and Complex Systems College of EngineeringPeking UniversityBeijing100871China Shenzhen Tenfong Technology Co. LTDShenzhen518055China School of Engineering Westlake UniversityHangzhou310024China department of Modern mechanics University of Science and Technology of ChinaHefei230026China Physics of Fluids Group University of Twente7500 AEEnschedeThe Netherlands

This paper presents a deep reflection on the advective wave equations for velocity vector and dilatation discovered in the past *** show that these equations can form the theoretical basis of modern gas dynamics,because they dominate not only various complex viscous and heat-conducting gas flows but also their associated longitudinal waves,including aero-generated *** aeroacoustics theory has been developing in a manner quite independently of gas dynamics;it is based on the advective wave equations for thermodynamic variables,say the exact Phillips equation of relative disturbance pressure as a representative ***,these equations do not cover the fluid flow that generates and propagates sound *** using them,one has to assume simplified base-flow models,which we argue is the main theoretical obstacle to identifying sound source and achieving effective noise ***,we show that the Phillips equation and alike is nothing but the first integral of the dilatation equation that also governs the longitudinal part of the flow ***,we conclude that modern aeroacoustics should merge back into the general unsteady gas dynamics as a special branch of it,with dilatation of multiple sources being a new additional and sharper sound variable.

关键词： Gas dynamics-aeroacoustics viscous compressible flow Advective wave equations Thermodynamic variables Dilatation Process splitting and coupling

CEPC Technical Design Report

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Radiation Detection Technology and Methods 2024年第1期8卷 I0003-I0016,1-1091页

作者： Waleed Abdallah Tiago Carlos Adorno de Freitas Konstantin Afanaciev Shakeel Ahmad Ijaz Ahmed Xiaocong Ai Abid Aleem Wolfgang Altmannshofer Fabio Alves Weiming An Rui An Daniele Paolo Anderle Stefan Antusch Yasuo Arai Andrej Arbuzov Abdesslam Arhrib Mustafa Ashry Sha Bai Yu Bai Yang Bai Vipul Bairathi Csaba Balazs Philip Bambade Yong Ban Tripamo Bandyopadhyay Shou-Shan Bao Desmond P.Barber Ayse Bat Varvara Batozskaya Subash Chandra Behera Alexander Belyaev Michele Bertucci Xiao-Jun Bi Yuanjie Bi Tianjian Bian Fabrizio Bianchi Thomas Biekotter Michela Biglietti Shalva Bilanishvili Deng Binglin Denis Bodrov Anton Bogomyagkov Serge Bondarenko Stewart Boogert Maarten Boonekamp Marcello Borri Angelo Bosotti Vincent Boudry Mohammed Boukidi Igor Boyko Ivanka Bozovic Giuseppe Bozzi Jean-Claude Brient Anastasiia Budzinskaya Masroor Bukhari Vladimir Bytev Giacomo Cacciapaglia Hua Cai Wenyong Cai wujun Cai Yijian Cai Yizhou Cai Yuchen Cai Haiying Cai Huacheng Cai Lorenzo Calibbi Junsong Cang Guofu Cao Jianshe Cao Antoine Chance Xuejun Chang Yue Chang Zhe Chang Xinyuan Chang Wei Chao Auttakit Chatrabhuti Yimin Che Yuzhi Che Bin Chen Danping Chen Fuqing Chen Fusan Chen Gang Chen Guoming Chen Hua-Xing Chen Huirun Chen Jinhui Chen Ji-Yuan Chen Kai Chen Mali Chen Mingjun Chen Mingshui Chen Ning Chen Shanhong Chen Shanzhen Chen Shao-Long Chen Shaomin Chen Shiqiang Chen Tianlu Chen Wei Chen Xiang Chen Xiaoyu Chen Xin Chen Xun Chen Xurong Chen Ye Chen Ying Chen Yukai Chen Zelin Chen Zilin Chen Gang Chen Boping Chen Chunhui Chen Hok Chuen Cheng Huajie Cheng Shan Cheng Tongguang Cheng Yunlong Chi Pietro Chimenti Wen Han Chiu Guk Cho Ming-Chung Chu Xiaotong Chu Ziliang Chu Guglielmo Coloretti Andreas Crivellin Hanhua Cui Xiaohao Cui Zhaoyuan Cui Brunella D'Anzi Ling-Yun Dai Xinchen Dai Xuwen Dai Antonio De Maria Nicola De Filippis Christophe De La Taille Francesca De Mori Chiara De Sio Elisa Del Core Shuangxue Deng Wei-Tian Deng Zhi Deng Ziyan Deng Bhupal Dev Tang Dewen Biagio Di Micco Ran Ding Siqin Dingl Yadong Ding Haiyi Dong Jianin AGH University of Science and Technology Faculty of Physics and Applied Computer ScienceKrakow Anhui University HefeiAnhui Applied Physics department Federal Urdu University of ArtsScience and TechnologyIslamabad Banaras Hindu University Institute of ScienceVaranasi Bandirma Onyedi Eylul University Bandirma Beihang University Beijing Beijing Computational Science Research Center Beijing Beijing Conveyi LTD Beijing Beijing Glass Research Institute Co. LtdBeijing Beijing Institute of Technology Beijing Beijing Normal University Beijing Brown University ProvidenceRI Budker Institute of Nuclear Physics Novosibirsk Cadi Ayyad University Laboratory of Fundamental and Applied PhysicsPolydisciplinary FacultyMarrakech Cairo University Giza Center for Theory and Computation National Tsing Hua UniversityHsinchu Central china Normal University WuhanHubei Central South University ChangshaHunan Centro de Fisica Teorica de Particulas Universidade Tecnica de LisboaLisboa Chengdu KaitengSifang Digital Radio&TV Equipment Co. LtdChengduSichuan china academy of engineering physics MianyangSichuan china building materials academy Beijing china Center of Advanced Science and Technology Beijing china Institute of Atomic Energy Beijing china Jiliang University HangzhouZhejiang china Nuclear Instrument CO. LTDBeijing china University of Geosciences Beijing china University of Geosciences WuhanHubei china University of Mining and Technology XuzhouJiangsu china West Normal University NanchongSichuan Chongqing University Department of PhysicsChongqing Chulalongkorn University Bangkok City University of Hong Kong Department of PhysicsHong Kong Cockcroft Institute Daresbury Cornell University IthacaNY CPPM(AMU/IPhU&CNRS/INP) Marseille Dalian Minzu University DalianLiaoning Dalian University of Technology Department of PhysicsDalian Deutsches Elektronen-Synchrotron DESY Hamburg Dzhelepov Laboratory of Nuclear Problems of Joint Institute for Nuclear Research(DLNP JINR) Dubna East china University Of Science And Technol

The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by china,fostered through extensive collaboration with international *** complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs *** its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs *** the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of *** Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering ***,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection *** is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 *** commencement of experiments and data collection could potentially be initiated in the mid-2030s.

关键词： initiated exceeding precise

Pulse-like ground motion observed during the 6 February 2023 M_(W)7.8 Pazarcık Earthquake(Kahramanmaraş,SE Türkiye)

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地震学报:英文版 2023年第4期36卷 328-339页

作者： Fan wu Junju Xie Zhao An Chenghao Lyu Tuncay Taymaz Tahir Serkan Irmak Xiaojun Li Zengping Wen Baofeng Zhou Institute of Geophysics China Earthquake AdministrationBeijing 100081China School of Earth and Space Sciences Peking UniversityBeijing 100871China department of Geophysical Engineering The Faculty of Minesİstanbul Technical UniversityMaslak 34467SarıyerİstanbulTürkiye department of Geophysical Engineering Kocaeli UniversityUmuttepe 41380KocaeliTürkiye College of Architecture and Civil Engineering Beijing University of TechnologyBeijing 100124China Institute of Engineering mechanics China Earthquake AdministrationHarbin 150080China

In this study,we analyzed 100 three-component strong ground motion records observed within 200 km of the causative fault of the 6 February 2023 M_(W)7.8 Pazarcık(Kahramanmaraş)Earthquake in SE Tü*** wavelet method was utilized to identify and analyze the characteristics of pulse-like ground motions in the near-fault region,while considering the uncertainty of the pulse orientation during the *** investigation focused on the effects of the focal mechanism and rupture process on the spatial distribution,pulse orientation,and maximum pulse direction of the observed pulse-like ground *** also analyzed the amplitude and period of the observed ground pulses and the effect of long-period amplification on the ground motion response *** results indicated the following:(1)A total of 21 typical ground velocity pulses were observed during this earthquake,exhibiting complex characteristics due to the influence of the strike-slip mechanism and rupture *** ground pulses(17 out of 21)were recorded within 20 km of the fault,in a wide range of orientations,including normal and parallel to the fault *** waveforms exhibited unidirectional features,indicating the effects of left-lateral fault *** pulses observed more than 20 km from the fault were mainly oriented normal to the *** waveforms were bidirectional with double-or multi-round trips as a result of rupture directivity.(2)The amplitudes of the observed pulses ranged from 30.5 to 220.0 cm/s,with the largest peak velocity of 220.0 cm/s observed at Station *** pulse periods ranged from 2.3 to 14.5 s,with the longest pulse period of 14.5 s observed at Station *** amplitude and period of the pulses observed during this earthquake were comparable to those of similar-magnitude global *** amplitude of the pulses decreased significantly with increasing fault distance,whereas the pulse period was not significantly affected by the fault distance.(3)Com

关键词： 2023 M_(W)7.8 Pazarcık Earthquake pulse-like ground motion response spectrum predominant period

Graphene-CdSe Nanobelt Solar Cells with Tunable Configurations

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Nano Research 2011年第9期4卷 891-900页

作者： Luhui Zhang Lili Fan Zhen Li Enzheng Shi Xinming Li Hongbian Li Chunyan Ji Yi Jia Jinquan Wei Kunlin Wang Hongwei Zhu Dehai wu Anyuan Cao department of Advanced Materials and Nanotechnology College of Engineering Peking University Beijing 100871 China Key Laboratory for Advanced Materials Processing Technology and department of Mechanical Engineering Tsinghua University Beijing 100084 China Center for Nano and Micro mechanics Tsinghua University Beijing 100084 China

We have combined two planar nanostructures, graphene and CdSe nanobelts, to construct Schottky junction solar cells with open-circuit voltages of about 0.5 V and cell efficiencies on the order of 0.1%. By covering transparent graphene or carbon nanotube （CNT） films on selected positions along macroscopically long CdSe nanobelts, we have demonstrated the fabrication of active solar cells with many different configurations and parallel connections from individual or multiple assembled nanobelts. The graphene-CdSe nanobelt solar cells reported here show a great flexibility in creating diverse device architectures, and might be scaled up for cell integration based on assembled nanobelt arrays and patterned graphene （or CNT） films.

关键词： Graphene CdSe nanobelts solar cells Schottky junction

Particle-in-cell simulations of laser–plasma interactions at solid densities and relativistic intensities: the role of atomic processes

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High Power Laser Science and Engineering 2018年第3期6卷 112-126页

作者： D. wu X. T. He W. Yu S. Fritzsche State Key Laboratory of High Field Laser Physics Shanghai Institute of Optics and Fine Mechanics Shanghai 201800 China Helmholtz lnstitut Jena D-07743 Jena Germany Key Laboratory of HEDP of the Ministry of Education Center for Applied Physics and Technology Peking University Beijing 100871 China Theoretisch-Physikalisches lnstitut Friedrich-Schiller-University Jena D-07743 Jena Germany

Direct numerical simulation of intense laser-solid interactions is still of great challenges, because of the many coupled atomic and plasma processes, such as ionization dynamics, collision among charged particles and collective electromagnetic fields, to name just a few. Here, we develop a new particle-in-cell （PIC） simulation code, which enables us to calculate laser-solid interactions in a more realistic way. This code is able to cover almost ＇all＇ the coupled physical processes. As an application of the new code, the generation and transport of energetic electrons in front of and within the solid target when irradiated by intense laser beams are studied. For the considered case, in which laser intensity is 1020 W. cm-2 and pre-plasma scale length in front of the solid is 10 Izm, several quantitative conclusions are drawn：（i） the collisional damping （although it is very weak） can significantly affect the energetic electrons generation in front of the target, （ii） the Bremsstrahlung radiation will be enhanced by 2-3 times when the solid is dramatically heated and ionized, （iii） the ＇cut-off＇ electron energy is lowered by an amount of 25% when both collision damping and Bremsstrahlung radiations are included, and （iv） the resistive electromagnetic fields due to Ohmic heating play nonignorable roles and must be taken into account in such interactions.

关键词： high energy density physics laser plasmas interaction

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基于人工神经网络的亚格子应力建模

力学学报 2021年第10期53卷 2667-2681页

作者：吴磊肖左利北京大学工学院力学与工程科学系北京100871 湍流与复杂系统国家重点实验室北京100871

亚格子(SGS)应力建模在湍流大涡模拟(LES)中有着极为重要的作用.传统亚格子应力模型存在相对误差较大、耗散过强等问题.近年来,计算机技术的发展使得人工神经网络(ANN)等机器学习方法逐渐成为亚格子应力建模型的新研究范式.本文着重考... 详细信息

亚格子(SGS)应力建模在湍流大涡模拟(LES)中有着极为重要的作用.传统亚格子应力模型存在相对误差较大、耗散过强等问题.近年来,计算机技术的发展使得人工神经网络(ANN)等机器学习方法逐渐成为亚格子应力建模型的新研究范式.本文着重考虑滤波宽度及雷诺数影响,在不可压缩槽道湍流中建立了亚格子应力的ANN模型.该模型以滤波后的直接数值模拟(f DNS)流场物理量及滤波尺度为输入信息,相应滤波尺度下的亚格子应力为输出量.通过对不同滤波尺度及不同雷诺数数据的训练,ANN模型能够给出与直接数值模拟(DNS)高度吻合的亚格子应力.此外,模型在亚格子耗散等非ANN建模量上也有着优异的预测性能,与基于DNS获得的对应物理量的相关系数大都在0.9以上,较梯度模型及Smagorinsky模型有明显提升.在后验测试中,ANN模型对流向平均速度剖面的预测同样优于梯度模型、Smagorinsky模型及隐式大涡模拟(ILES)等传统LES模型.在脉动速度均方根预测方面,除了某些法向位置外ANN模型的性能整体上相对其他3个模型有所提升.然而,随着网格尺度的增大ANN模型预测的结果与fDNS结果的偏差逐渐增大.总之,ANN方法在发展高精度亚格子应力模型上具有很大的潜力.

关键词：湍流大涡模拟人工神经网络亚格子应力滤波宽度

Facile fabrication of a biocompatible composite gel with sustained release of aspirin for bone regeneration

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Bioactive Materials 2022年第5期7卷 130-139页

作者： Yunfan Zhang Xueyu Dou Lingyun Zhang Hufei Wang Ting Zhang Rushui Bai Qiannan Sun Xing Wang Tingting Yu Decheng wu Bing Han Xuliang Deng department of Orthodontics Peking University School and Hospital of StomatologyBeijingPR China National Center of Stomatology National Clinical Research Center for Oral DiseasesNational Engineering Laboratory for Digital and Material Technology of StomatologyBeijing Key Laboratory for Digital StomatologyResearch Center of Engineering and Technology for Computerized Dentistry Ministry of HealthNMPA Key Laboratory for Dental MaterialsBeijingPR China Beijing National Laboratory for Molecular Sciences Institute of ChemistryChinese Academy of SciencesBeijingPR China University of Chinese Academy of Sciences BeijingPR China department of Geriatric Dentistry Peking University School and Hospital of StomatologyBeijingPR China

Hydrogels are extracellular-matrix-like biomimetic materials that have wide biomedical applications in tissue engineering and drug ***,most hydrogels cannot simultaneously fulfill the mechanical and cell compatibility *** the present study,we prepared a semi-interpenetrating network composite gel(CG)by incorporating short chain chitosan(CS)into a covalent tetra-armed poly(ethylene glycol)*** addition to satisfying physicochemical,mechanics,biocompatibility,and cell affinity requirements,this CG easily encapsulated acetylsalicylic acid(ASA)via electrostatic interactions and chain entanglement,achieving sustained release for over 14 days and thus promoting periodontal ligament stem cell(PDLSC)proliferation and osteogenic *** vivo studies corroborated the capacity of PDLSCs and ASA-laden CG to enhance new bone regeneration in situ using a mouse calvarial bone defect *** might be attributed to PDLSCs and host mesenchymal stem cells expressing monocyte chemoattractant protein-1,which upregulated M2 macrophage recruitment and polarization in situ,indicating its appealing potential in bone tissue engineering.

关键词： Hydrogel Aspirin Chitosan Drug sustained-release Bone tissue engineering

Oil spill cleanup from sea water by carbon nanotube sponges

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Frontiers of Materials Science 2013年第2期7卷 170-176页

作者： Ke ZHU Yuan-Yuan SHANG Peng-Zhan SUN Zhen LI Xin-Ming LI Jin-Quan WEI Kun-Lin WANG De-Hai wu An-Yuan CAO Hong-Wei ZHU School of Materials Science and Engineering Tsinghua University Beijing 100084 China department of Materials Science and Engineering College of Engineering Peking University Beijing 100871 China Center for Nano and Micro mechanics Tsinghua University Beijing 10008i China

Oil spills in the sea have caused many serious environmental problems worldwide. In this study, carbon nanotube （CNT） sponges were used to cleanup oil slicks on sea waters. This method was compared with two traditional representative sorbents, including polypropylene fiber fabric and woolen felt. The CNT sponges had a larger oil sorption capacity than the other two sorbents. The maximum oil sorption capacity （Qm） of the CNT sponge was 92.30 g/g, which was 12 to 13.5 times larger than the Qm of the other two sorbents （the Qm of the polypropylene fiber fabric and woolen felt were 7.45 and 6.74 g/g, respectively）. In addition, unlike the other two sorbents, the CNT sponge was super- hydrophobic and did not adsorb any water during oil spill cleanup. CNT sponges are potentially very useful for cleaning up oil spills from sea water.

关键词： carbon nanotube (CNT) sponge oil spill sorption capacity sea water

CuI-Si Heterojunction Solar Cells with Carbon Nanotube Films as Flexible Top-Contact Electrodes

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Nano Research 2011年第10期4卷 979-986页

作者： Peixu Li ShanshanWang Yi Jia Zhen Li Chunyan Ji Luhui Zhang Hongbian Li Enzheng Shi Zuqiang Bian Chunhui Huang Jinquan Wei Kunlin Wang Hongwei Zhu Dehai wu Anyuan Cao department of Mechanical Engineering Tsinghua University Beijing 100084 China College of Chemistry and Molecular Engineering Peking University Beijing 100871 China College of Engineering Peking University Beijing 100871 China Center for Nano and Micro mechanics Tsinghua University Beijing 100084 China These authors contributed equally to this work.

We report the fabrication of CuI-Si heterojunction solar cells with carbon nanotubes （CNTs） as a transparent electrode. A flexible CNT network was transferred onto tile top of a polycrystalline CuI layer, making a conformal coating with good contact with the underlying CuI. The solar cells showed power conversion efficiencies in the range of 6% to 10.5%, while the efficiency degradation was less than 10% after the device was stored in air for 8 days. Compared with conventional rigid electrodes such as indium tin oxide （ITO） glass, the flexibility of the CNT films ensures better contact with the active layers and removes the need for press-contact electrodes. Degraded cells can recover their original performance by acid doping of the CNT electrode. Our results suggest that CNT films are suitable electrical contacts for rough materials and structures with an uneven surface.

关键词： Carbon nanotubes flexible electrodes heterojunction solar cells