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Molecular Dynamics Simulations and Experimental Investigations of Atomic Diffusion Behavior at Bonding Interface in an Explosively Welded Al/Mg Alloy Composite Plate

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Acta Metallurgica Sinica(English Letters) 2017年第10期30卷 983-991页

作者： Ting-Ting Zhang Wen-xian Wang Jun Zhou Xiao-Qing Cao Rui-Shan Xie Yi Wei College of Materials Science and Engineering Taiyuan University of Technology Shanxi Key Laboratory of Advanced Magnesium-Based Materials Ministry of Education Key Laboratory of Interface Science and Engineering in Advanced Materials Ministry of Education Department of Mechanical Engineering Pennsylvania State University ErieThe Behrend College Department of Mechanical Engineering Key Laboratory for Advanced Materials Processing TechnologyTsinghua University

In this study, 6061 aluminum alloy and AZ31 B magnesium alloy composite plate was fabricated through explosive welding. Molecular dynamics（MD） simulations were conducted to investigate atomic diffusion behavior at bonding interface in the AI/Mg composite plate. Corresponding experiments were conducted to validate the simulation results. The results show that diffusion coefficient of Mg atom is larger than that of A1 atom and the difference between these two coefficients becomes smaller with increasing collision velocity. The diffusion coefficient was found to depend on collision velocity and angle. It increases linearly with collision velocity when the collision angle is maintained constant at 10° and decreases linearly with collision angle when the collision velocity is maintained constantly at 440 m/s. Based on our MD simulation results and Fick＇s second law, a mathematical formula to calculate the thickness of diffusion layer was proposed and its validity was verified by relevant experiments. Transmission electron microscopy and energy-dispersive system were also used to investigate the atomic diffusion behavior at the bonding interface in the explosively welded 6061/AZ31B composite plate. The results show that there were obvious Al and Mg atom diffusion at the bonding interface,and the diffusion of magnesium atoms from magnesium alloy plate to aluminum alloy plate occurs much faster than the diffusion of aluminum atoms to the magnesium alloy plate. These findings from the current study can help to optimize the explosive welding process.

关键词： Al/Mg composite plate Explosive welding Molecular dynamics simulation Atomic diffusionbehavior

Modified Harn Authentication Key Exchange Scheme

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The Journal of China Universities of Posts and Telecommunications 2000年第1期7卷 75-77页

作者： LIZi-chen LIZhong-xian 等 InformationSecurityCenter BeijingUniversityofPostsandTelecommunicationsBeijing100876P.R.China Infor

Recently, Harn proposed one digital signature scheme for Diffie-Hellman key exchange system. In this paper, we point out at first that there is a weakness in Harn's system and then we propose two modified schemes to a... 详细信息

关键词： Digital signature Key exchange Cryptography

Enhanced alumina film adhesion of Hf/Y-doped iron-aluminum alloys during high-temperature oxidation:a new observation

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Rare Metals 2019年第9期38卷 877-884页

作者： Dong-Qing Li Li-xian Zhou Jun Zhan Jing-Chao Wang Jian Gu Jia-Jun Si Department of Transmission and Transformation Engineering Mechanics China Electric Power Research Institute

The cyclic oxidation behavior of Hf/Y-doped B2 FeAl intermetallics at 1373 K was *** an undoped FeAl alloy,premature spallation of the alumina film occurs due to the formation of numerous voids at the film/alloy interface and apparent shrinkage in the *** contrast to this,doping with either Hf or Y significantly improves the interfacial adhesion between the alumina film and the alloy substrate,particularly with *** observation in combination with Anger electron spectroscopic analysis suggests that in addition to prohibiting interfacial void formation and alleviating film shrinkage,the addition of Hf in the FeAl alloy could consolidate the film/alloy interface by directly participating in chemical bonding across the interface as a Hf *** causes the spallation of alumina film from the equiaxed grains/columnar grains interface rather than the bottom of the film.

关键词： Intermetallics Reactive elements Thermal cycling Alumina film Interfacial adhesion Segregation

Growth and in situ transformation of TiO2 and HTiOF3 crystals on chitosan-polyvinyl alcohol co-polymer substrates under vapor phase hydrothermal conditions

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Nano Research 2016年第3期9卷 745-754页

作者： Tianxing Wu Guozhong Wang Xiaoguang Zhu Porun Liu xian Zhang Haimin Zhang Yunxia Zhang Huijun Zhao Key Laboratory of Materials Physics Centre for Environmental and Energy Nanomaterials Anhui Key Laboratory of Nanomaterials and Nanostructures Institute of Solid State Physics Chinese Academy of Sciences Hefei 230031 China Centre for Clean Environment and Energy Gold Coast Campus Griffith University Queensland 4222 Australia

A chitosan-polyvinyl alcohol （CS/PVA） co-polymer substrate possessing a large number of amino and hydroxyl groups is used as a substrate to induce the direct growth and in situ sequential transformation of fitanate crystals under HF vapor phase hydrothermal conditions. The process involves four distinct formation/ transformation stages. HTiOF3 crystals with well-defined hexagonal shapes are formed during stage I, and are subsequently transformed into {001} faceted anatase TiO2 crystal nanosheets during stage II. Interestingly, the formed anatase TiO2 crystals are further transformed into cross-shaped and hollow square- shaped HTiOF3 crystals during stages III and IV, respectively. Although TiO2 crystal phases and facet transformations under hydrothermal conditions have been previously reported, in situ crystal transformations between different titanate compounds have not been widely reported. Such crystal formation/ transformations are likely due to the presence of large numbers of amino groups in the CS/PVA substrate. When celluloses possessing only hydroxyl groups are used as a substrate, the direct formation of {001} faceted TiO2 nanocrystal sheets is observed （rather than any sequential crystal transformations）. This substrate organic functional group-induced crystal formation/transformation approach could be applicable to other material systems.

关键词： vapor phasehydrothermal synthesis crystal transformation titanate compounds

Reparable Key Distribution Protocols for Internet Environments

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The Journal of China Universities of Posts and Telecommunications 2000年第1期7卷 86-88页

作者： YANGYi-xian NIUXin-xin 等 Information Security Center Beijing University of Posts and TelecommunicationsBeijing100876R.P.China Infor

It has claimed that any practical way to achieve perfect reparability for key distribution protocol (KDP) could only be futile. Fortunately, this paper presents reparable KDPs for internet environments with the use of... 详细信息

关键词： key distribution protocols cryptology network security

In situ analysis of dynamic evolution of the additive-regulated cathode processes in quasi-solid-state lithium-metal batteries

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Science China Chemistry 2023年第10期66卷 2921-2928页

作者： Jian-Xin Tian Hui-Juan Guo Jing Wan Gui-xian Liu Rui Wen Li-Jun Wan CAS Key Laboratory of Molecular Nanostructure and Nanotechnology CAS Research/Education Center for Excellence in Molecular SciencesBeijing National Laboratory for Molecular ScienceInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

The implementation of high-energy-density storage devices can be facilitated by the built-in situ cathode electrolyte interphase(CEI)between Ni-rich cathodes and gel polymer electrolytes,as it improves interfacial compatibility and enhances *** the interphase processes of cathode materials,including the structural evolution and the formation of cathode electrolyte interphase upon charging/discharging,is crucial for the design of solid-state lithium ***,we employed in situ atomic force microscopy(AFM)to investigate the effects of lithium difluoro(oxalato)borate(Li DFOB)on the dynamic evolution of the cathode *** the presence of Li DFOB,the adhesion of nanoparticles and a thin amorphous film on the cathode surface resulted in the formation of a homogeneous CEI,inducing the production of LixPFyas ***,the stable CEI formed between the cathode and electrolyte helps maintain the integrity of the composition and structure,reduces interfacial resistance,and improves the cycle stability of the *** visualization of in situ AFM in quasi-solid-state lithium-metal batteries provides valuable insights into the distinct nanostructures and growth dynamics of Li DFOB-mediated CEI on the LiNi_(6)Co_(2)Mn_(2)O_(2) cathode,thus offering a universal and convenient technique for interfacial analysis and a mechanistic understanding of solid-state batteries.

关键词： atomic force microscopy electrochemistry interfacial dynamics solid-state lithium batteries cathode electrolyte interphase

Spiro-fused bicyclo[3,2,2]octatriene-cored triptycene:synthesis,molecular packing,and functional aggregates

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Science China Chemistry 2021年第11期64卷 1976-1984页

作者： Qing Liu xian Chen Zhibiao Zhou Tingting Huang Yanpei Wang Sheng Xie Zebing Zeng Ben Zhong Tang State Key Laboratory of Chemo/Biosensing and Chemometrics College of Chemistry and Chemical EngineeringHunan UniversityChangsha410082China Aggregation-Induced Emission(AIE)Institute Guangzhou Development DistrictHuangpuGuangzhou510530China Shenzhen Institute of Aggregate Science and Technology School of Science and EngineeringThe Chinese University of Hong KongShenzhen518172China

Aggregate science has led to the existence of functional properties at the aggregate level that significantly differs from those of corresponding single-molecule species,leading to a number of novel conceptual materials with state-dependent *** developing such materials,new molecular scaffolds that allow modulating the structural and functional properties of aggregates in a controlled manner could be extremely *** this study,we report a class of spiro-fused bicyclo[3,2,2]octatriene triptycene derivatives with a unique 3 D molecular scaffolding structure that displays aggregation-induced emission(AIE)activity with bright solid-state blue *** core scaffold features a Y-shaped bicyclo[3,2,2]octatriene backbone and a vertical crossover arrangement of adjacent spiro-conjugated *** classic bicyclo[2,2,2]octatrienes with high rigidity,this stereoscopic bicyclo[3,2,2]octatriene containing a seven-membered ring allows retaining certain flexibility in the molecular scaffold,which results in a weak fluorescence in dilute solutions(Φ_(F)<10%).However,the corresponding molecular aggregates emit intense fluorescence(Φ_(F)=50%-75%)and show prominent AIE activity because of the restriction of intramolecular scaffold ***,in principle,these stereoscopic scaffold constructions with partially restricted flexibility facilitate the assembly of multiple different crystalline packing structures in both porous and nonporous forms depending on the growth conditions of crystalline *** obtained crystals with regular voids(12.85×6.89Aeach)show reversible luminescence in response to the adsorption/desorption of iodine *** materials based on an unusual 3 D scaffold exhibit a high degree of structural modulation at the aggregate level and demonstrate potential applications in chemical sensing and flexible optoelectronics,which may open up the exploration of highly stereoscopic molecular building blocks for developing functi

关键词： aggregate science triptycene aggregation-induced emission organic porous material

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海上救助打捞知识图谱构建及应用

安全 2024年第6期45卷 32-38页

作者：彭忠卫陈思聪吴江湖李显焦宇交通运输部上海打捞局上海200082 上海海事大学海洋科学与工程学院上海201306

针对海上救助打捞(MRS)领域知识体系零散及海量救助打捞案例数据无法有效挖掘和利用的问题,通过对救助打捞事故案例和标准规范文件的详细分析,获取5类事故对象、19个场景及每个场景所需的关键救助打捞能力。基于这些场景和能力需求之间... 详细信息

针对海上救助打捞(MRS)领域知识体系零散及海量救助打捞案例数据无法有效挖掘和利用的问题,通过对救助打捞事故案例和标准规范文件的详细分析,获取5类事故对象、19个场景及每个场景所需的关键救助打捞能力。基于这些场景和能力需求之间的关系,采用自顶向下与自底向上方式相结合构建MRS内部实体和属性图,对数据进行结构化处理并映射到设计图谱,并结合决策推荐规则实现知识图谱的构建和应用。研究结果表明:MRS知识图谱能够有效进行救助打捞知识的检索查询、知识展示与信息统计可视化及辅助决策方案推荐,为相关领域的作业提供更加系统化和智能化的支持工具。

关键词：海上救助打捞(MRS) 知识图谱数据体系事故案例

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交锁髓内钉固定腓骨下段骨折合并下胫腓损伤

中国矫形外科杂志 2024年第14期32卷 1318-1321页

作者：徐政吕飞徐蔚蔚董献成杜建伟沈书明扬州大学附属医院(扬州市第一人民医院)骨科江苏扬州225000

[目的]探讨交锁髓内钉联合胫腓螺钉固定腓骨下段骨折合并下胫腓损伤的临床疗效。[方法]回顾性分析2019年1月—2022年2月在本院应用交锁髓内钉治疗的腓骨下段骨折合并下胫腓损伤29例患者的临床资料。评价临床及影像资料。[结果]所有患者... 详细信息

[目的]探讨交锁髓内钉联合胫腓螺钉固定腓骨下段骨折合并下胫腓损伤的临床疗效。[方法]回顾性分析2019年1月—2022年2月在本院应用交锁髓内钉治疗的腓骨下段骨折合并下胫腓损伤29例患者的临床资料。评价临床及影像资料。[结果]所有患者均顺利完成手术,手术时间(51.8±10.3)min,术中出血量(68.3±14.3)ml,切口总长度(42.5±3.6)mm,随访时间(13.7±2.4)个月。随时间推移,患者VAS评分、AOFAS评分及踝ROM均显著改善(P<0.05)。影像方面,与术前相比,患者术后6个月及末次随访下胫腓骨重叠(tibiofibular overlap,TFO)[(2.1±0.7)mm,(8.1±1.3)mm,(8.0±1.1)mm,P<0.001]、距骨小腿角(talocrural angle,TCA)[(73.9±4.2)°,(83.1±3.0)°,(82.4±2.9)°,P<0.001]均显著增加,而下胫腓间隙(tibiofibular clear space,TFCS)[(8.3±1.3)mm,(4.3±0.5)mm,(4.4±0.5)mm,P<0.001]显著减小。[结论]交锁髓内钉联合下胫腓螺钉可有效治疗腓骨下段骨折合并下胫腓损伤,具有切口小,出血少,抗旋转,且下胫腓固定可靠等优势。

关键词：腓骨下段骨折髓内钉下胫腓联合内固定