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Discontinuity development patterns and the challenges for 3D discrete fracture network modeling on complicated exposed rock surfaces 被引量:1
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作者 Wen Zhang Ming Wei +8 位作者 Ying Zhang Tengyue li Qing Wang Chen Cao Chun Zhu zhengwei li Zhenbang Nie Shuonan Wang Han Yin 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第6期2154-2171,共18页
Natural slopes usually display complicated exposed rock surfaces that are characterized by complex and substantial terrain undulation and ubiquitous undesirable phenomena such as vegetation cover and rockfalls.This st... Natural slopes usually display complicated exposed rock surfaces that are characterized by complex and substantial terrain undulation and ubiquitous undesirable phenomena such as vegetation cover and rockfalls.This study presents a systematic outcrop research of fracture pattern variations in a complicated rock slope,and the qualitative and quantitative study of the complex phenomena impact on threedimensional(3D)discrete fracture network(DFN)modeling.As the studies of the outcrop fracture pattern have been so far focused on local variations,thus,we put forward a statistical analysis of global variations.The entire outcrop is partitioned into several subzones,and the subzone-scale variability of fracture geometric properties is analyzed(including the orientation,the density,and the trace length).The results reveal significant variations in fracture characteristics(such as the concentrative degree,the average orientation,the density,and the trace length)among different subzones.Moreover,the density of fracture sets,which is approximately parallel to the slope surface,exhibits a notably higher value compared to other fracture sets across all subzones.To improve the accuracy of the DFN modeling,the effects of three common phenomena resulting from vegetation and rockfalls are qualitatively analyzed and the corresponding quantitative data processing solutions are proposed.Subsequently,the 3D fracture geometric parameters are determined for different areas of the high-steep rock slope in terms of the subzone dimensions.The results show significant variations in the same set of 3D fracture parameters across different regions with density differing by up to tenfold and mean trace length exhibiting differences of 3e4 times.The study results present precise geological structural information,improve modeling accuracy,and provide practical solutions for addressing complex outcrop issues. 展开更多
关键词 Complicated exposed rock surfaces Discontinuity characteristic variation Three-dimensional discrete fracture network modeling Outcrop study Vegetation cover and rockfalls
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Edaravone promotes functional recovery after mechanical peripheral nerve injury 被引量:4
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作者 Teng Zhang zhengwei li +3 位作者 Jianli Dong Feng Nan Tao li Qing Yu 《Neural Regeneration Research》 SCIE CAS CSCD 2014年第18期1709-1715,共7页
Edaravone has been shown to reduce ischemia/reperfusion-induced peripheral nerve injury. However, the therapeutic effect of edaravone on peripheral nerve injury caused by mechanical factors is unknown. In the present ... Edaravone has been shown to reduce ischemia/reperfusion-induced peripheral nerve injury. However, the therapeutic effect of edaravone on peripheral nerve injury caused by mechanical factors is unknown. In the present study, we established a peripheral nerve injury model by crushing the sciatic nerve using hemostatic forceps, and then administered edaravone 3 mg/kg intraperitoneally. The sciatic functional index and superoxide dismutase activity of the sciatic nerve were increased, and the malondialdehyde level was decreased in animals in the edaravone group compared with those in the model group. Bcl-2 expression was increased, but Bax expres- sion was decreased in anterior horn cells of the L4-6 spinal cord segments. These results indicated that edaravone has a neuroprotective effect following peripheral nerve injury caused by mechan- ical factors through alleviating free radical damage to cells and inhibiting lipid peroxidation, as well as regulating apoptosis-related protein expression. 展开更多
关键词 nerve regeneration peripheral nerve injury mechanical injury sciatic nerve injury EDARAVONE lipid peroxidation free radical damage MALONDIALDEHYDE superoxide dismutase Bcl-2 Bax NSFC grant neural regeneration
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Model free optimization of building cooling water systems with refined action space 被引量:2
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作者 Qiaofeng Xiong zhengwei li +1 位作者 Wenxia Cai Zhechao Wang 《Building Simulation》 SCIE EI CSCD 2023年第4期615-627,共13页
Deep Q Network(DQN)is an efficient model-free optimization method,and has the potential to be used in building cooling water systems.However,due to the high dimension of actions,this method requires a complex neural n... Deep Q Network(DQN)is an efficient model-free optimization method,and has the potential to be used in building cooling water systems.However,due to the high dimension of actions,this method requires a complex neural network.Therefore,both the required number of training samples and the length of convergence period are barriers for real application.Furthermore,penalty function based exploration may lead to unsafe actions,causing the application of this optimization method even more difficult.To solve these problems,an approach to limit the action space within a safe area is proposed in this paper.First of all,the action space for cooling towers and pumps are separated into two sub-regions.Secondly,for each type of equipment,the action space is further divided into safe and unsafe regions.As a result,the convergence speed is significantly improved.Compared with the traditional DQN method in a simulation environment validated by real data,the proposed method is able to save the convergence time by 1 episode(one cooling season).The results in this paper suggest that,the proposed DQN method can achieve a much quicker learning speed without any undesired consequences,and therefore is more suitable to be used in projects without pre-learning stage. 展开更多
关键词 building cooling water system cooling tower cooling water pump DQN controller convergence speed
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Mechanics of bioinspired imaging systems 被引量:1
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作者 zhengwei li Yu Wang Jianliang Xiao 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2016年第1期11-20,共10页
Imaging systems in nature have attracted a lot of research interest due to their superior optical and imaging characteristics, Recent advancements in materials science, mechanics, and stretchable electronics have led ... Imaging systems in nature have attracted a lot of research interest due to their superior optical and imaging characteristics, Recent advancements in materials science, mechanics, and stretchable electronics have led to successful development of bioinspired cameras that resemble the structures and functions of biological light-sensing organs. In this review, we discuss some recent progresses in mechanics of bioinspired imaging systems, including tunable hemispherical eyeball camera and artificial compound eye camera. The mechanics models and results reviewed in this article can provide efficient tools for design and optimization of such systems, as well as other related optoelectronic systems that combine rigid elements with soft substrates. 展开更多
关键词 Mechanics Bioinspired imaging system Eyeball camera Compound eye camera Stretchable electronics
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Pose Estimation of Space Targets Based on Model Matching for Large-Aperture Ground-Based Telescopes
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作者 zhengwei li Jianli Wang +2 位作者 Tao Chen Bin Wang Yuanhao Wu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2018年第11期271-286,共16页
With the development of adaptive optics and post restore processing techniques,large aperture ground-based telescopes can obtain high-resolution images(HRIs)of targets.The pose of the space target can be estimated fro... With the development of adaptive optics and post restore processing techniques,large aperture ground-based telescopes can obtain high-resolution images(HRIs)of targets.The pose of the space target can be estimated from HRIs by several methods.As the target features obtained from the image are unstable,it is difficult to use existing methods for pose estimation.In this paper a method based on real-time target model matching to estimate the pose of space targets is proposed.First,the physicallyconstrained iterative deconvolution algorithm is used to obtain HRIs of the space target.Second,according to the 3D model,the ephemeris data,the observation time of the target,and the optical parameters of the telescope,the simulated observation image of the target in orbit is rendered by a scene simulation program.Finally,the target model searches through yaw,pitch,and roll until the correlation between the simulated observation image and the actual observation image shows an optimal match.The simulation results show that the proposed pose estimation method can converge to the local optimal value with an estimation error of about 1.6349°. 展开更多
关键词 Ground-based TELESCOPE POSE estimation CORRELATION MATCHING space TARGET image RESTORATION
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Collagen-based bioinks for regenerative medicine: Fabrication, application and prospective
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作者 zhengwei li Changshun Ruan Xufeng Niu 《Medicine in Novel Technology and Devices》 2023年第1期15-33,共19页
In the field of regenerative medicine,the importance of 3D bioprinting is self-evident and nonnegligible.However,3D bioprinting technology also requires bioink with excellent performance as support material to fabrica... In the field of regenerative medicine,the importance of 3D bioprinting is self-evident and nonnegligible.However,3D bioprinting technology also requires bioink with excellent performance as support material to fabricate a multi-functional bioinspired scaffold.Collagen-based bioink is regarded as an ideal 3D bioprinting ink for its excellent biocompatibility,controllable printability and cell loading property.It is an important breakthrough in regenerative medicine with the progress of collagen-based bioink,which fabricates bioinspired scaffolds with different functions and is applied in different repair scenarios.This review summarizes the different applications of collagen-based bioink and classifies them as soft tissue and hard tissue according to the target region.The applications of target region in soft tissues include skin,cartilage,heart and blood vessels,while in hard tissues include femur,skull,teeth and spine.When the collagen-based bioink is applied in repairing soft tissue,the requirements of function are higher,while the mechanical properties must be further improved in repairing hard tissue.We further summarize the characteristics of collagen-based bioink and point out the most important properties that should be considered in different repair scenarios,which can provide reference for the preparation of bioinks with different functions.Finally,we point out the main challenges faced by collagen-based bioink and prospect the future research directions. 展开更多
关键词 COLLAGEN 3D printing Bioink Soft tissue Hard tissue
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Construction and Empirical Research of Comprehensive Financial Analysis Index System Based on Cash Flowl
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作者 zhengwei li 《Journal of Contemporary Educational Research》 2020年第10期55-57,共3页
This paper first elaborates on the importance of cash flow in building a comprehensive financial indicator system.On one hand,it is the relationship between cash flow and the assessment of the company’s solvency,prof... This paper first elaborates on the importance of cash flow in building a comprehensive financial indicator system.On one hand,it is the relationship between cash flow and the assessment of the company’s solvency,profitability,and operating ability.On the other hand,it is the theoretical basis of financial analysis based on cash flow.We then introduced the construction principles of the financial analysis index system based on cash flow,and lastly analyzed the financial data of Xiaomi for empirical research. 展开更多
关键词 Financial indicator system Cash Flow
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Overview to the Hard X-ray Modulation Telescope (Insight-HXMT) Satellite 被引量:19
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作者 Shuang-Nan Zhang TiPei li +116 位作者 FangJun Lu liMing Song YuPeng X u CongZhan liu Yong Chen XueLei Cao QingCui Bu Zhi Chang Gang Chen li Chen TianXiang Chen YiBao Chen YuPeng Chen Wei Cui WeiWei Cui JingKang Deng YongWei Dong Yuan Yuan Du MinXue Fu GuanHua Gao He Gao Min Gao MingYu Ge YuDong Gu Ju Guan Can Gungor ChengCheng Guo DaWei Han Wei Hu Yue Huang Jia Huo ShuMei Jia LuHua Jiang WeiChun Jiang Jing Jin YongJie Jin Bing li ChengKui li Gang li MaoShun li Wei li Xian li XiaoBo li XuFang li YanGuo li ZiJian li zhengwei li XiaoHua liang JinYuan liao GuoQing liu HongWei liu ShaoZhen liu XiaoJing liu Yuan liu YiNong liu Bo Lu XueFeng Lu Tao Luo Xiang Ma Bin Meng Yi Nang JianYin Nie Ge Ou JinLu Qu Na Sai RenCheng Shang GuoHong Shen liang Sun Ying Tan lian Tao Youli Tuo Chen Wang ChunQin Wang GuoFeng Wang HuanYu Wang Juan Wang WenShuai Wang YuSa Wang XiangYang Wen BaiYang Wu BoBing Wu Mei Wu GuangCheng Xiao Shaolin Xiong linli Yan JiaWei Yang Sheng Yang YanJi Yang QiBin Yi Bin Yuan AiMei Zhang ChunLei Zhang ChengMo Zhang Fan Zhang HongMei Zhang Juan Zhang Qiang Zhang ShenYi Zhangs Shu Zhang Tong Zhang WanChang Zhang Wei Zhang WenZhao Zhang Yi Zhang YiFei Zhang YongJie Zhang Yue Zhang Zhao Zhang Zhi Zhang Ziliang Zhang HaiSheng Zhao XiaoFan Zhao ShiJie Zheng JianFeng Zhou YuXuan Zhu Yue Zhu Renlin Zhuang 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2020年第4期2-19,共18页
As China’s first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band(1-250 ke V) slat-collimator-based X-ray as... As China’s first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band(1-250 ke V) slat-collimator-based X-ray astronomy satellite with the capability of all-sky monitoring in 0.2-3 Me V. It was designed to perform pointing, scanning and gamma-ray burst(GRB)observations and, based on the Direct Demodulation Method (DDM), the image of the scanned sky region can be reconstructed.Here we give an overview of the mission and its progresses, including payload, core sciences, ground calibration/facility, ground segment, data archive, software, in-orbit performance, calibration, background model, observations and some preliminary results. 展开更多
关键词 X-and γ-ray telescopes and instrumentation neutron stars black holes X-ray binaries γ-ray bursts
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The High Energy X-ray telescope (HE) onboard the Insight-HXMT astronomy satellite 被引量:12
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作者 CongZhan liu YiFei Zhang +30 位作者 XuFang li XueFeng Lu Zhi Chang zhengwei li AiMei Zhang YongJie Jin HuiMing Yu Zhao Zhang MinXue Fu YiBao Chen JianFeng Ji YuPeng Xu JingKang Deng RenCheng Shang GuoQing liu FangJun Lu ShuangNan Zhang YongWei Dong TiPei li Mei Wu YanGuo li HuanYu Wang BoBing Wu YongJie Zhang Zhi Zhang Shaolin Xiong Yuan liu Shu Zhang HongWei liu YiJung Yang Fan Zhang 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2020年第4期20-34,共15页
The Insight-Hard X-ray Modulation Telescope(Insight-HXMT) is a broadband X-ray and γ-ray(1-3000 ke V) astronomy satellite. One of its three main telescopes is the High Energy X-ray telescope(HE). The main detector pl... The Insight-Hard X-ray Modulation Telescope(Insight-HXMT) is a broadband X-ray and γ-ray(1-3000 ke V) astronomy satellite. One of its three main telescopes is the High Energy X-ray telescope(HE). The main detector plane of HE comprises 18 Na I(Tl)/Cs I(Na) phoswich detectors, where Na I(Tl) is used as the primary detector to measure ~ 20-250 ke V photons incident from the field of view(FOV) defined by collimators, and Cs I(Na) is used as the active shielding detector to Na I(Tl) by pulse shape discrimination. Additionally, Cs I(Na) is used as an omnidirectional γ-ray monitor. The HE collimators have a diverse FOV,i.e. 1.1°×5.7°(15 units), 5.7°×5.7°(2 units), and blocked(1 unit). Therefore, the combined FOV of HE is approximately5.7°×5.7°. Each HE detector has a diameter of 190 mm resulting in a total geometrical area of approximately 5100 cm2, and the energy resolution is ~15% at 60 ke V. For each recorded X-ray event by HE, the timing accuracy is less than 10 μs and the deadtime is less than 10 μs. HE is used for observing spectra and temporal variability of X-ray sources in the 20-250 ke V band either by pointing observations for known sources or scanning observations to unveil new sources. Additionally, HE is used for monitoring the γ-ray burst in 0.2-3 Me V band. This paper not only presents the design and performance of HE instruments but also reports results of the on-ground calibration experiments. 展开更多
关键词 X-RAY TELESCOPE HXMT calibration scintillation DETECTOR
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Bioinspired mineralized collagen scaffolds for bone tissue engineering 被引量:18
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作者 zhengwei li Tianming Du +1 位作者 Changshun Ruan Xufeng Niu 《Bioactive Materials》 SCIE 2021年第5期1491-1511,共21页
Successful regeneration of large segmental bone defects remains a major challenge in clinical orthopedics,thus it is of important significance to fabricate a suitable alternative material to stimulate bone regeneratio... Successful regeneration of large segmental bone defects remains a major challenge in clinical orthopedics,thus it is of important significance to fabricate a suitable alternative material to stimulate bone regeneration.Due to their excellent biocompatibility,sufficient mechanical strength,and similar structure and composition of natural bone,the mineralized collagen scaffolds(MCSs)have been increasingly used as bone substitutes via tissue engineering approaches.Herein,we thoroughly summarize the state of the art of MCSs as tissue-engineered scaffolds for acceleration of bone repair,including their fabrication methods,critical factors for osteogenesis regulation,current opportunities and challenges in the future.First,the current fabrication methods for MCSs,mainly including direct mineral composite,in-situ mineralization and 3D printing techniques,have been proposed to improve their biomimetic physical structures in this review.Meanwhile,three aspects of physical(mechanics and morphology),biological(cells and growth factors)and chemical(composition and cross-linking)cues are described as the critical factors for regulating the osteogenic feature of MCSs.Finally,the opportunities and challenges associated with MCSs as bone tissue-engineered scaffolds are also discussed to point out the future directions for building the next generation of MCSs that should be endowed with satisfactorily mimetic structures and appropriately biological characters for bone regeneration. 展开更多
关键词 COLLAGEN MINERALIZATION SCAFFOLD Bone repair 3D printing BIOMECHANICS
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基于合成磁场的声学非互易
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作者 陈召宪 李正伟 +4 位作者 翁经锴 梁彬 陆延青 程建春 Andrea Alù 《Science Bulletin》 SCIE EI CAS CSCD 2023年第19期2164-2169,M0003,共7页
通过设计特定的时空调制,合成磁性的概念最近被提出以实现对光子和声子等电荷中性粒子的非互易操控,但现有方案存在着隔离度低、信号频率变化等问题.本文设计了一种新型耦合共振腔系统,其中动态耦合的相位作为实现声学合成磁场的新机制... 通过设计特定的时空调制,合成磁性的概念最近被提出以实现对光子和声子等电荷中性粒子的非互易操控,但现有方案存在着隔离度低、信号频率变化等问题.本文设计了一种新型耦合共振腔系统,其中动态耦合的相位作为实现声学合成磁场的新机制并打破了系统的时间反演对称性,最终取得了优异的声波非互易传输.基于旋转波近似方法,作者严格推导出了实现系统强非互易声传输的参数条件.通过优化动态耦合之间的相位差以及耦合强度,实验展示了隔离度达45-dB和正向传输率达0.85的优异单向声传输.此外,这种单向声传输具有始末态频率不变和隔离方向可电控等重要特性.该研究突破了现有声波单向操控机制在效率和隔离度方面的局限,并为实现弗洛奎和非线性声学拓扑绝缘体提供了新途径. 展开更多
关键词 隔离度 信号频率 动态耦合 非线性声学 拓扑绝缘体 耦合共振 耦合强度 声传输
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Migrating behaviors of interfacial elements and oxide layers during diffusion bonding of 6063Al alloys using Zn interlayer in air
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作者 Pu Zhao zhengwei li +3 位作者 Zhiwu Xu Xuesong Leng Anqi Tong Jiuchun Yan 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2023年第24期119-131,共13页
The oxide layer on the surface has always been a key obstacle to achieving the diffusion bonding of Al alloys.It is a challenge for performing diffusion bonding without removing oxide layers.Herein,diffusion bonding o... The oxide layer on the surface has always been a key obstacle to achieving the diffusion bonding of Al alloys.It is a challenge for performing diffusion bonding without removing oxide layers.Herein,diffusion bonding of Al alloy retaining continuous oxide layers was successfully achieved in the air by a low-temperature and low-pressure diffusion bonding mothed using a Zn interlayer.During the bonding processes,conducted at 360℃ and 3 MPa,Zn diffused into Al through cracks of thin oxide layers to form the joint composed Al/(diffusion layer)/(oxide layer)/(Zn)/(oxide layer)/(diffusion layer)/Al.The diffusion layers were composed of Zn-Al eutectoid,and the oxide layer included nanocrystals and amorphous Al_(2)O_(3).The shear strength of joints containing continuous oxide layers was about 30 MPa.Interestingly,the migration behavior toward the joint center of the interfacial oxide layers was observed with consuming of the Zn interlayer.The cracking phenomenon,the“subcutaneous diffusion”and the migration behavior of oxide layers were verified and analyzed by the diffusion bonding of anodized 6063Al-6063Al.Subsequently,the dynamic migration mechanism of oxide layers with elements diffusion and bonding interface strengths were discussed in detail.The ability to join Al alloys in the air at low temperatures and low pressure suggests a highly practical and economic method for diffusion bonding. 展开更多
关键词 6063Al alloy Diffusion bonding Zn interlayer Oxide layers Migration behavior
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The enhanced X-ray Timing and Polarimetry mission—eXTP 被引量:18
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作者 ShuangNan Zhang Andrea Santangelo +149 位作者 Marco Feroci YuPeng Xu FangJun Lu Yong Chen Hua Feng Shu Zhang Sφren Brandt Margarita Hernanz Luca Baldini Enrico Bozzo Riccardo Campana Alessandra De Rosa YongWei Dong Yuri Evangelista Vladimir Karas Norbert Meidinger Aline Meuris Kirpal Nandra Teng Pan Giovanni Pareschi Piotr Orleanski QiuShi Huang Stephane Schanne Giorgia Sironi Daniele Spiga Jiri Svoboda Gianpiero Tagliaferri Christoph Tenzer Andrea Vacchi Silvia Zane Dave Walton ZhanShan Wang Berend Winter Xin Wu Jean J.M.in't Zand Mahdi Ahangarianabhari Giovanni Ambrosi Filippo Ambrosino Marco Barbera Stefano Basso Jörg Bayer Ronaldo Bellazzini Pierluigi Bellutti Bruna Bertucci Giuseppe Bertuccio Giacomo Borghi XueLei Cao Franck Cadoux Francesco Ceraudo TianXiang Chen Yu Peng Chen Jerome Chevenez Marta Civitani Wei Cui WeiWei Cui Thomas Dauser Ettore Del Monte Sergio Di Cosimo Sebastian Diebold Victor Doroshenko Michal Dovciak YuanYuan Du Lorenzo Ducci QingMei Fan Yannick Favre Fabio Fuschino JoséLuis Ga'lvez Min Gao MingYu Ge Olivier Gevin Marco Grassi QuanYing Gu YuDong Gu DaWei Han Bin Hong Wei Hu Long Ji ShuMei Jia WeiChun Jiang Thomas Kennedy Ingo Kreykenbohm Irfan Kuvvetli Claudio Labanti Luca Latronico Gang li MaoShun li Xian li Wei li zhengwei li Olivier limousin HongWei liu XiaoJing liu Bo Lu Tao Luo Daniele Macera Piero Malcovati Adrian Martindale Malgorzata Michalska Bin Meng Massimo Minuti Alfredo Morbidini Fabio Muleri Stephane Paltani Emanuele Perinati Antonino Picciotto Claudio Piemonte JinLu Qu Alexandre Rachevski Irina Rashevskaya Jerome Rodriguez Thomas Schanz ZhengXiang Shen liZhi Sheng JiangBo Song liMing Song Carmelo Sgro liang Sun Ying Tan Phil Uttley Bo Wang DianLong Wang GuoFeng Wang Juan Wang LangPing Wang YuSa Wang Anna L.Watts XiangYang Wen Jörn Wilms Shaolin Xiong JiaWei Yang Sheng Yang YanJi Yang Nian Yu WenDa Zhang Gianluigi Zampa Nicola Zampa Andrzej A.Zdziarski AiMei Zhang ChengMo Zhang Fan Zhang Long Zhang Tong Zhang Yi Zhang Xiaoli Zhang Ziliang Zhang BaoSheng Zhao ShiJie Zheng Yu Peng Zhou Nicola Zorzi J.Frans Zwart 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2019年第2期3-27,共25页
In this paper we present the enhanced X-ray Timing and Polarimetry mission—eXTP. eXTP is a space science mission designed to study fundamental physics under extreme conditions of density, gravity and magnetism. The m... In this paper we present the enhanced X-ray Timing and Polarimetry mission—eXTP. eXTP is a space science mission designed to study fundamental physics under extreme conditions of density, gravity and magnetism. The mission aims at determining the equation of state of matter at supra-nuclear density, measuring effects of QED, and understanding the dynamics of matter in strong-field gravity. In addition to investigating fundamental physics, eXTP will be a very powerful observatory for astrophysics that will provide observations of unprecedented quality on a variety of galactic and extragalactic objects. In particular, its wide field monitoring capabilities will be highly instrumental to detect the electro-magnetic counterparts of gravitational wave sources.The paper provides a detailed description of:(1) the technological and technical aspects, and the expected performance of the instruments of the scientific payload;(2) the elements and functions of the mission, from the spacecraft to the ground segment. 展开更多
关键词 X-ray instrumentation X-ray polarimetry X-ray timing space mission:eXTP
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Refill friction stir spot welding of 5083-O aluminum alloy 被引量:12
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作者 Zhiwu Xu zhengwei li +1 位作者 Shude Ji liguo Zhang 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2018年第5期878-885,共8页
In this work,refill friction stir spot welding(RFSSW) was used to weld 2 mm-thick 5083-O alloy.The Box–Behnken experimental design was used to investigate the effect of welding parameters on the joint lap shear pro... In this work,refill friction stir spot welding(RFSSW) was used to weld 2 mm-thick 5083-O alloy.The Box–Behnken experimental design was used to investigate the effect of welding parameters on the joint lap shear property.Results showed that a surface indentation of 0.3 mm effectively eliminated the welding defects.Microhardness of the stir zone(SZ) was higher than that of the base material(BM) and the hardness decreased with increasing the heat input during welding.The optimum failure load of 7.72 k N was obtained when using rotating speed of 2300 rpm,plunge depth of 2.4 mm and refilling time of 3.5 s.Three fracture modes were obtained during the lap shear test and all were affected by the hook defect. 展开更多
关键词 Refill friction stir spot welding KEYHOLE Secondary phases MICROHARDNESS Lap shear failure load
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Insight-HXMT observations of the first binary neutron star merger GW170817 被引量:20
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作者 TiPei li Shaolin Xiong +107 位作者 ShuangNan Zhang FangJun Lu liMing Song XueLei Cao Zhi Chang Gang Chen li Chen TianXiang Chen Yong Chen YiBao Chen YuPeng Chen Wei Cui WeiWei Cui JingKang Deng YongWei Dong YuanYuan Du MinXue Fu GuanHua Gao He Gao Min Gao MingYu Ge YuDong Gu Ju Guan ChengCheng Guo DaWei Han Wei Hu Yue Huang Jia Huo ShuMei Jia LuHua Jiang WeiChun Jiang Jing Jin YongJie Jin Bing li ChengKui li Gang li MaoShun li Wei li Xian li XiaoBo li XuFang li YanGuo li ZiJian li zhengwei li XiaoHua liang JinYuan liao CongZhan liu GuoQing liu HongWei liu ShaoZhen liu XiaoJing liu Yuan liu YiNong liu Bo Lu XueFeng Lu Tao Luo Xiang Ma Bin Meng Yi Nang JianYin Nie Ge OU JinLu Qu Na Sai liang Sun Yin Tan lian Tao WenHui Tao Youli Tuo GuoFeng Wang HuanYu Wang Juan Wang WenShuai Wang YuSa Wang XiangYang Wen BoBing WU Mei Wu GuangCheng Xiao He Xu YuPeng Xu linli Yan JiaWei Yang Sheng Yang YanJi Yang AiMei Zhang ChunLei Zhang ChengMo Zhang Fan Zhang HongMei Zhang Juan Zhang Qiang Zhang Shu Zhang Tong Zhang Wei Zhang WanChang Zhang WenZhao Zhang Yi Zhang Yue Zhang YiFei Zhang YongJie Zhang Zhao Zhang Ziliang Zhang HaiSheng Zhao Jianling Zhao XiaoFan Zhao ShiJie Zheng Yue Zhu YuXuan Zhu Changlin Zou 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2018年第3期26-33,共8页
Finding the electromagnetic (EM) counterpart of binary compact star merger, especially the binary neutron star (BNS) merger, is critically important for gravitational wave (GW) astronomy, cosmology and fundament... Finding the electromagnetic (EM) counterpart of binary compact star merger, especially the binary neutron star (BNS) merger, is critically important for gravitational wave (GW) astronomy, cosmology and fundamental physics. On Aug. 17, 2017, Advanced LIGO and Fermi/GBM independently triggered the first BNS merger, GW170817, and its high energy EM counterpart, GRB 170817A, respectively, resulting in a global observation campaign covering gamma-ray, X-ray, UV, optical, IR, radio as well as neutrinos. The High Energy X-ray telescope (HE) onboard Insight-HXMT (Hard X-ray Modulation Telescope) is the unique high-energy gamma-ray telescope that monitored the entire GW localization area and especially the optical counterpart (SSS17a/AT2017gfo) with very large collection area (M000 cm2) and microsecond time resolution in 0.2-5 MeV. In addition, Insight-HXMT quickly implemented a Target of Opportunity (TOO) observation to scan the GW localization area for potential X-ray emission from the GW source. Although Insight-HXMT did not detect any significant high energy (0.2-5 MeV) radiation from GW170817, its observation helped to confirm the unexpected weak and soft nature of GRB 170817A. Meanwhile, Insight-HXMT/HE provides one of the most stringent constraints (-10-7 to 104 erg/cm2/s) for both GRB170817A and any other possible precursor or extended emissions in 0.2-5 MeV, which help us to better understand the properties of EM radiation from this BNS merger. Therefore the observation of Insight-HXMT constitutes an important chapter in the full context of multi-wavelength and multi-messenger observation of this historical GW event. 展开更多
关键词 GW170817 BNS merger gravitational wave electromagnetic counterpart
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Effect of Reverse-threaded Pin on Mechanical Properties of Friction Stir Lap Welded Alclad 2024 Aluminum Alloy 被引量:9
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作者 Yumei Yue zhengwei li +2 位作者 Shude Ji Yongxian Huang Zhenlu Zhou 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2016年第7期671-675,共5页
In friction stir welding (FSW), tool geometry plays an important role in joint quality. In order to improve mechanical properties of friction stir lap welding (FSLW)joint, a tool with a reverse-threaded pin was de... In friction stir welding (FSW), tool geometry plays an important role in joint quality. In order to improve mechanical properties of friction stir lap welding (FSLW)joint, a tool with a reverse-threaded pin was designed in the present study. Using 2024-T4 aluminum alloy as the research object, tools with the full- threaded pin and reverse-threaded pin were used in FSLW. Results showed that, when using the same parameter combination, FSLW joint using the reverse-threaded pin owned bigger effective sheet thick- ness (EST), bigger lap width and better lap shear failure strength. Compared with the full-threaded pin, fracture mode of the FSLW joint changed from shear fracture mode to tensile fracture mode when the reverse-threaded pin was used. Fracture morphologies presented ductile fracture. 展开更多
关键词 Friction stir lap weldingReverse-threaded pinHookFracture position
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Mechanical, forming and biological properties of Ti-Fe-Zr-Y alloys prepared by 3D printing 被引量:1
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作者 liying Han Cunshan Wang zhengwei li 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2019年第7期1323-1333,共11页
Biomedical Ti-Fe-Zr-Y alloys were prepared by 3D printing on pure titanium substrate. The influences of Zr on mechanical, forming, and biological properties of the alloys were investigated in detail. The results showe... Biomedical Ti-Fe-Zr-Y alloys were prepared by 3D printing on pure titanium substrate. The influences of Zr on mechanical, forming, and biological properties of the alloys were investigated in detail. The results showed that with increasing the Zr addition, the surface roughness, friction coefficient and worn volume decrease at first and then increase, the lowest values obtained at 5.86Zr addition. The ultimate compression stress and specific strength gradually decrease. The studied alloys have no cytotoxicity. They can promote the early adhesion and proliferation of cells. The eutectic alloy with 5.86 at.% Zr addition has the best ability of apatite deposition, it exhibits a better comprehensive performance among the studied alloys, which is superior to the Ti70.5Fe29.5 and Ti-6Al-4V alloys. 展开更多
关键词 Laser 3D PRINTING TITANIUM alloy Properties
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Differential pressure reset strategy based on reinforcement learning for chilled water systems 被引量:1
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作者 Xinfang Zhang Zhenhai li +2 位作者 zhengwei li Shunian Qiu Hai Wang 《Building Simulation》 SCIE EI CSCD 2022年第2期233-248,共16页
Air conditioning water systems account for a large proportion of building energy consumption.In a pressure-controlled water system,one of the key measures to save energy is to adjust the differential pressure setpoint... Air conditioning water systems account for a large proportion of building energy consumption.In a pressure-controlled water system,one of the key measures to save energy is to adjust the differential pressure setpoints during operation.Typically,such adjustments are based either on certain rules,which rely on operator experience,or on complicated models that are not easy to calibrate.In this paper,a data-driven control method based on reinforcement learning is proposed.The main idea is to construct an agent model that adapts to the researched problem.Instead of directly being told how to react,the agent must rely on its own experiences to learn.Compared with traditional control strategies,reinforcement learning control(RLC)exhibits more accurate and steady performances while maintaining indoor air temperature within a limited range.A case study shows that the RLC strategy is able to save substantial amounts of energy. 展开更多
关键词 water system differential pressure reset reinforcement learning control energy saving
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