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Geodesy and Geodynamics 2022年第1期13卷 1-10页

作者： Feng Li peng zhai Jinshui Huang Hongbo Tan Mengcheng National Geophysical Observatory School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei230026China Earthquake Administration of Jiangsu Province Nanjing210014China CAS Center for Excellence in Comparative Planetology Hefei230026China

The study of postseismic deformation is important for constraining the viscoelastic properties of the Earth and inverting the post-earthquake process.The levelling survey revealed that the area near Bei-chuan elevated 5.3 cm about two years after the M_(W) 7.9 Wenchuan earthquake(05/12/2008),during which the area underwent significant downward movement.The GPS horizontal displacements showed a non-monotonic variation after the Wenchuan earthquake.In this study,a 3-D viscoelastic finite element model is employed to simulate the coseismic and postseismic deformation of the Wenchuan earthquake.The numerical simulations show that the lateral heterogeneity across the Longmenshan fault plays an important role in the postseismic displacements.The results reveal that the coseismic defor-mation is not sensitive to the horizontal heterogeneity,but the postseismic deformation is sensitive to it.The postseismic deformation of the horizontally heterogeneous model is generally consistent with the observations of all geodetic surveys,such as GPS,InSAR and levelling,but not for the horizontally homogenous model.We also find that the non-monotonous variation of the postseismic deformation of the Wenchuan earthquake could be explained by a viscoelastic relaxation model with lateral heterogeneous medium across the Longmenshan fault.

关键词： M_(W)7.9 Wenchuan earthquake Postseismic deformation Viscoelastic relaxation Horizontal heterogeneity Three-dimensional finite element

High-performance multifunctional(Hf^(0.2)Nb_(0.2)Ta_(0.2)Ti_(0.2)Zr_(0.2))C high-entropy ceramic reinforced with low-loading 3D hybrid graphene–carbon nanotube

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Journal of Advanced Ceramics 2023年第2期12卷 341-356页

作者： Jialin SUN Jun ZHAO Yonghui ZHOU peng zhai Xialun YUN Zhifu HUANG Hui ZHANG Guohua ZHANG School of Mechanical Electrical&Information EngineeringShandong University(Weihai)Weihai 264209China State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and EngineeringXi’an Jiaotong UniversityXi’an 710049China Key Laboratory of High Efficiency and Clean Mechanical Manufacture of Ministry of Education School of Mechanical EngineeringShandong UniversityJinan 250061China State Key Laboratory for Manufacturing System Engineering School of Mechanical EngineeringXi’an Jiaotong UniversityXi’an 710049China State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China

There has been growing interest in the high-entropy ceramic(HEC)recently owing to its tailorable compositions and microstructures,versatile properties,together with promising structural and functional applications.However,inferior fracture toughness(KIC)and damage tolerance restricted many practical applications of the HEC.Herein,we addressed this challenge by incorporating a threedimensional graphene–carbon nanotube(3D G–CNT)as toughening agent in(Hf_(0.2)Nb_(0.2)Ta_(0.2)Ti_(0.2)Zr_(0.2))C.The resulting enhanced 3D G–CNT/(Hf_(0.2)Nb_(0.2)Ta_(0.2)Ti_(0.2)Zr_(0.2))C featured an outstanding toughness of 8.23 MPa·m^(1/2),while remaining superior strength(763 MPa)and hardness(24.7 GPa).An ultralow friction coefficient(0.15)coupled with an ultralow wear rate(w,2.6×10^(−7) mm^(3)/(N·m))in the 3D G–CNT/(Hf_(0.2)Nb_(0.2)Ta_(0.2)Ti_(0.2)Zr_(0.2))C was obtained primarily as a function of lubricating scrolls,in which two-dimensional(2D)graphene acted as a tribolayer,and one-dimensional(1D)carbon nanotubes acted as nano ball bearings embedded inside.Strikingly,the 3D G–CNT/(Hf_(0.2)Nb_(0.2)Ta_(0.2)Ti_(0.2)Zr_(0.2))C exhibited rather low thermal conductivity(κ)yet excellent electrical conductivity(σ,1.3×10^(6) S/m)in comparison with the pure(Hf_(0.2)Nb_(0.2)Ta_(0.2)Ti_(0.2)Zr_(0.2))C.This study provided great potential for maximizing the physical and functional properties of the HEC for various applications.

关键词： high-entropy ceramic(HEC) three-dimensional graphene-carbon nanotube(3D G-CNT) toughening lubricating thermal conductivity(κ)/electrical conductivity(σ)

物联网环境下基于SM9算法和区块链技术的身份认证方法

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信息网络安全 2024年第2期24卷 179-187页

作者：翟鹏何泾沙张昱北京工业大学信息学部北京100124 济宁学院计算机科学与工程学院济宁273100

物联网环境下的终端设备需要进行相互识别和身份认证来保障网络安全和数据安全,身份认证是物联网安全保障的第一道防线,现有的传统公钥密码体制(PKI)过程繁琐、计算量大,不能很好地满足资源受限、开放、分布式物联网环境。文章基于SM9... 详细信息

物联网环境下的终端设备需要进行相互识别和身份认证来保障网络安全和数据安全,身份认证是物联网安全保障的第一道防线,现有的传统公钥密码体制(PKI)过程繁琐、计算量大,不能很好地满足资源受限、开放、分布式物联网环境。文章基于SM9标识密码算法设计了一种基于区块链的物联网终端身份认证方案,基于计算性Diffie-Hellman困难问题、q-Diffie-Hellman逆问题和双线性DH困难问题的假设下,可以极大满足机密性和不可伪造性,更加符合物联网实际应用环境。该方案采用设备身份标识作为公钥,简化了密钥分发管理流程,另外区块链作为一种去中心化的底层存储数据库,用来记录密钥、证书、签名等信息,可以为认证流程进行可信背书。通过性能和Proverif形式化安全性分析,并与目前主流的几种认证方式进行比较,证明该方案可以满足物联网环境下时间、性能及安全性的需求。

关键词：物联网 SM9算法身份认证区块链

Influences of across-strike heterogeneous viscosity on the earthquake cycle in a three-dimensional strike-slip fault model

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Earthquake Research Advances 2023年第3期3卷 30-41页

作者： peng zhai Feng Li Jinshui Huang Mengcheng National Geophysical Observatory School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei230026China Jiangsu Earthquake Agency Nanjing210014China CAS Center for Excellence in Comparative Planetology Hefei230026China

Geodetic observations have shown that there exist large differences in the viscosity of the deep lithosphere across many large strike-slip faults.Heterogeneity in lithospheric viscosity structure can influence the efficiency of stress transfer and thus may have a significant effect on the earthquake cycle.Until now,how the lateral viscosity variation across strike-slip faults affects the earthquake cycles is still not well understood.Here,we investigate the effects of across-strike viscosity variation on long-term earthquake behaviors with a three-dimensional strike-slip fault model.Our model is a quasi-static model which is controlled by the slip-weakening friction law and powerlaw rheology.By comparing with the reference case,we find that low viscosity on one side of the fault results in a smaller rupture area but with a higher Coulomb stress drop on the ruptured fault region.In addition,low viscosity also leads to a small Coulomb stress accumulation rate.These combined effects increase the earthquake recurrence interval by approximately 10%and the earthquake moments by about 30%when the low viscosity is related to a geothermal gradient of 30 K/km.In addition,across-strike viscosity variation causes asymmetric interseismic ground surface deformation rate.As the viscosity contrast increases,the difference in the interseismic ground surface deformation rate between the two sides of the fault gradually increases,although the asymmetric feature is not pronounced.This asymmetry of interseismic ground deformation rate across a strike-slip fault is supposed to result in asymmetric coseismic deformation if the long-term plate motion velocity is invariant.As a result,this kind of asymmetry of interseismic deformation may influence the evaluation of potential earthquake hazards along large strike-slip faults with lateral viscosity contrast.

关键词： Across-strike viscosity variation Friction law Power-law rheology Earthquake cycle Asymmetric interseismic deformation

Novel crosslinked alginate/hyaluronic acid hydrogels for nerve tissue engineering

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Frontiers of Materials Science 2013年第3期7卷 269-284页

作者： Min-Dan WANG peng zhai David J. SCHREYER Ruo-Shi ZHENG Xiao-Dan SUN Fu-zhai CUI Xiong-Biao CHEN Division of Biomedical Engineering University of Saskatchewan 57 Campus Dr. Saskatoon SK S7N5A9 Canada Department of Anatomy and Cell Biology University of Saskatchewan 107 Wiggins Rd. Saskatoon SK S7N5E5 Canada School of Materials Science and Engineering Tsinghua University Beijing 100084 China Department of Mechanical Engineering University of Saskatchewan 57 Campus Dr. Saskatoon SK S7N5A9 Canada

CT： Artificial tissue engineering scaffods can potentially provide supportand guidance for the regrowth of severed axons following nerve injury. In this study a hybrid biomaterial composed of alginate and hyaluronic acid （HA） was synthesized characterized in terms of its suitability for covalent modification, biocompatibility fir living Schwann cells and feasibility to construct three dimensional （3D） Carbodiimide mediated amide formation for the purpose of covalent crosslinking of the HA was carried out in the presence of calcium ions that ionically crosslink alginate.Amide formation was found to be dependent on the concentrations of cabodiimide and calclum chloride. The double-crosslinked composite hydrogels display blocompatibllity that is comparable to simple HA hydrogels, allowing for Schwann cell survival and significant difference was found between composite hydrogels made from different of alginate and HA. A 3D BioPIotterTM rapid prototyping system was used to fabricats 3D scaffolds. The result indicated that combining HA with alginate facilitated the fabrication process and that 3D scaffolds with porous inner structure can be fabricated ;from the composite hydrogels, but not from HA alone. This information provides a basis for continuing in vitro and in vivo tests of the suitability of alginate/HA hydrogel as a biomaterial to create living cell scaffolds to support nerve regeneration.

关键词： hyaluronic acid （HA） alginate hydrogel scaffold nerve injury tissueengineering

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基于非局部注意力机制的在线多目标跟踪算法

计算机应用与软件 2024年第2期41卷 178-187页

作者：郑龙澍林野翟鹏张立华复旦大学工程与应用技术研究院上海200433 上海智能机器人工程技术研究中心上海200433 智能机器人教育部工程研究中心上海200433 季华实验室广东佛山528000 吉林省人工智能与无人系统工程研究中心吉林长春130000

针对多目标跟踪任务在人群拥挤场景存在目标漏检、遮挡等问题,在CenterTrack框架基础上引入非局部注意力机制以捕捉多个目标之间、目标与场景之间的非局部依赖关系,提出基于空间非局部注意力残差块的跟踪模型;并进一步扩展到时空域,建... 详细信息

针对多目标跟踪任务在人群拥挤场景存在目标漏检、遮挡等问题,在CenterTrack框架基础上引入非局部注意力机制以捕捉多个目标之间、目标与场景之间的非局部依赖关系,提出基于空间非局部注意力残差块的跟踪模型;并进一步扩展到时空域,建立基于时空关系非局部注意力模块的跟踪模型,同时实现检测和跟踪任务。在MOT17、MOT16、2D MOT15三个数据集的实验结果表明,提出的两种在线跟踪模型较CenterTrack算法有明显提升,且在MOT17中MOTA(Multiple Object Tracking Accuracy)指标达到了目前较为先进的水平,为62.4%和62.5%,验证了该算法的有效性。

关键词：多目标跟踪计算机视觉非局部注意力机制深度学习

An underwater acoustic direct sequence spread spectrum communication system using dual spread spectrum code

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Frontiers of Information Technology & Electronic Engineering 2018年第8期19卷 972-983页

作者： Lan-jun LIU Jian-fen LI Lin ZHOU peng zhai Hao ZHAO Jiu-cai JIN Zhi-chao LV College of Engineering Ocean University of China The First Institute of Oceanography State Oceanic Administration College of Underwater Acoustic Engineering Harbin Engineering University

With the goal of achieving high stability and reliability to support underwater point-to-point communications and code division multiple access(CDMA) based underwater networks, a direct sequence spread spectrum based underwater acoustic communication system using dual spread spectrum code is proposed. To solve the contradictions between the information data rate and the accuracy of Doppler estimation, channel estimation, and frame synchronization, a data frame structure based on dual spread spectrum code is designed. A long spread spectrum code is used as the training sequence, which can be used for data frame detection and synchronization, Doppler estimation, and channel estimation. A short spread spectrum code is used to modulate the effective information data. A delay cross-correlation algorithm is used for Doppler estimation, and a correlation algorithm is used for channel estimation. For underwater networking, each user is assigned a different pair of spread spectrum codes. Simulation results show that the system has a good anti-multipath, anti-interference, and anti-Doppler performance, the bit error rate can be smaller than 10^(-6) when the signal-to-noise ratio is larger than-10 dB, the data rate can be as high as 355 bits/s, and the system can be used in the downlink of CDMA based networks.

关键词： Underwater acoustic communication Direct sequence spread spectrum Doppler estimation and compensation Channel estimation and equalization Gold code Single carrier Code division multiple access

无人机平飞下激光雷达和双目视觉融合的SLAM建图

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计算机应用与软件 2024年第4期41卷 192-199页

作者：吴秉慧董志岩翟鹏张立华复旦大学工程与应用技术研究院上海200433 上海智能机器人工程技术研究中心上海200433 智能机器人教育部工程研究中心上海200433 季华实验室广东佛山528000

针对无人机在较快运动下使用单一传感器难以有效构建地图的问题,提出一种基于LiDAR与双目融合的建图方法。利用LiDAR获取远处环境信息,提取物体的边界信息减少数据冗余,实现预先地图的构建;使用双目获取近处的信息,同时利用改进的特征... 详细信息

针对无人机在较快运动下使用单一传感器难以有效构建地图的问题,提出一种基于LiDAR与双目融合的建图方法。利用LiDAR获取远处环境信息,提取物体的边界信息减少数据冗余,实现预先地图的构建;使用双目获取近处的信息,同时利用改进的特征金字塔法以实现特征快速提取,与LiDAR预建地图并行计算提高运行效率;最后将视觉特征与LiDAR预建地图融合构建二维地图。实验表明,该方法在无人机不同速度下可构建可靠性更高、更精确的环境地图,可为快速无人机的实时避障提供位置信息。

关键词：无人机同时定位与地图构建传感器融合特征提取金字塔法

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不同产地杜仲叶活性成分的定量分析

陕西科技大学学报 2024年第4期42卷 70-77页

作者：龚频柯瀛瀛翟鹏涛翟文俊李白存郑本忠崔梦娇陕西科技大学食品科学与工程学院陕西西安710021 陕西学前师范学院生命科学与食品工程学院陕西西安710000 陕西天承生物科技股份有限公司陕西西安710075

通过杜仲叶中主要活性成分绿原酸的提取率,优化杜仲叶活性成分的提取工艺,比较不同产地杜仲叶组成及含量的差异.以绿原酸为目标产物,通过单因素实验和Box-Behnken模型,并采用高效液相色谱法测定秦仲叶和华仲叶中芦丁、松脂醇二葡萄糖苷... 详细信息

通过杜仲叶中主要活性成分绿原酸的提取率,优化杜仲叶活性成分的提取工艺,比较不同产地杜仲叶组成及含量的差异.以绿原酸为目标产物,通过单因素实验和Box-Behnken模型,并采用高效液相色谱法测定秦仲叶和华仲叶中芦丁、松脂醇二葡萄糖苷、金丝桃苷、绿原酸及没食子酸五种活性成分含量.单因素条件对两者叶的提取效果影响均为:提取温度>提取时间>乙醇体积分数>料液比.在最佳提取条件下,秦仲叶绿原酸提取率为62.94%,华仲叶绿原酸提取率为47.84%.两者叶中绿原酸含量最高,秦仲叶中芦丁、松脂醇二葡萄糖苷含量比华仲叶高出1.97倍和6.59倍,但华仲叶中金丝桃苷和绿原酸含量比秦仲叶高出1.41倍和1.16倍.本研究旨在为不同地域杜仲树种的选育以及临床上应用标准提供理论依据,帮助更加全面地评价不同产地杜仲药材质量.

关键词：绿原酸响应面法高效液相色谱不同产地定量

Not in Control,but Liable?Attributing Human Responsibility for Fully Automated Vehicle Accidents

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Engineering 2024年第2期33卷 121-132页

作者： Siming zhai Lin Wang peng Liu Center for Psychological Sciences Zhejiang UniversityHangzhou 310063China Department of Library and Information Science Incheon National UniversityIncheon 22012Republic of Korea

Human agency has become increasingly limited in complex systems with increasingly automated decision-making capabilities.For instance,human occupants are passengers and do not have direct vehicle control in fully automated cars(i.e.,driverless cars).An interesting question is whether users are responsible for the accidents of these cars.Normative ethical and legal analyses frequently argue that individuals should not bear responsibility for harm beyond their control.Here,we consider human judgment of responsibility for accidents involving fully automated cars through three studies with seven experiments(N=2668).We compared the responsibility attributed to the occupants in three conditions:an owner in his private fully automated car,a passenger in a driverless robotaxi,and a passenger in a conventional taxi,where none of these three occupants have direct vehicle control over the involved vehicles that cause identical pedestrian injury.In contrast to normative analyses,we show that the occupants of driverless cars(private cars and robotaxis)are attributed more responsibility than conventional taxi passengers.This dilemma is robust across different contexts(e.g.,participants from China vs the Republic of Korea,participants with first-vs third-person perspectives,and occupant presence vs absence).Furthermore,we observe that this is not due to the perception that these occupants have greater control over driving but because they are more expected to foresee the potential consequences of using driverless cars.Our findings suggest that when driverless vehicles(private cars and taxis)cause harm,their users may face more social pressure,which public discourse and legal regulations should manage appropriately.

关键词： Fully automated vehicle accidents Responsibility attribution Controllability Foreseeability