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内蒙古交通网络结构特征与城镇空间关联研究

干旱区资源与环境 2022年第7期36卷 93-99页

作者：董秉坤郑陈柔雨杨叶飞吉林大学管理学院长春130022 中国科学院东北地理与农业生态研究所长春130102 中国科学院大学资源与环境学院北京100049 北京交通大学经济管理学院北京100044

交通网络是反映城镇联系和结构的重要途径。文中基于内蒙古公路、铁路、航空的客运班次数据和复杂网络分析方法,在对交通网络结构解析的基础上,探讨分析城镇相互作用关系,提炼城镇关联模式。结果表明:1)交通网络下的内蒙古表现为核心城... 详细信息

交通网络是反映城镇联系和结构的重要途径。文中基于内蒙古公路、铁路、航空的客运班次数据和复杂网络分析方法,在对交通网络结构解析的基础上,探讨分析城镇相互作用关系,提炼城镇关联模式。结果表明:1)交通网络下的内蒙古表现为核心城市和重要节点城镇指向性。2)公路网络具备空间邻近和属地特征,局部范围呈现带状集聚模式。铁路网络以呼包银-集通线为发展轴进行延伸扩展,航空网络以呼和浩特的对外联系为主。3)各个交通网络具有小世界效应,但关键性城镇节点影响作用有限,网络化发育不完善。4)公路、铁路、航空网络下的城镇联系模式分别凝练为单核-多点分散型、轴线型、轴-辐型,显示出内蒙古内外联系的空间组织形式。研究结果为内蒙古交通体系优化和区域布局完善提供科学参考。

关键词：交通网络空间结构城镇关联内蒙古

Computer Simulation of the Interphase Boundary Evolution in Ni_(75)Al_xV_(25-x) Alloy

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Journal of Materials Science & Technology 2005年第3期21卷 395-398页

作者： YongshengLI zhengchen YanliLU YongxinWANG SchoolofMaterialsScienceandEngineering NorthwesternPolytechnicalUniversityXi'an710072China SchoolofMaterialsScienceandEngineering NorthwesternPolytechnicalUniversityXiran710072China//StateKeyLaboratoryofSolidificationProcessingNorthwesternPolytechnicalUniversityXi'an710072China SchoolofMaterialsScienceandEngineering NorthwesternPolytechnicalUniversityXi'an710072China

The interphase boundary evolution of ordered phase in Ni75AlxV25-x alloy during precipitation was simulated on atomic-scale based on the microscopic phase-field dynamic model. The results show that the second phase precipitated from the interphase boundary formed by the first phase and the disordered matrix at high temperature, and from the interphase boundaries of the first phase at low temperature. L12 phase had obvious selective orientation when precipitated from the interphase boundaries of D022- L12 phase nucleated easily at the interphase boundaries formed by [10] and [01] directions of D022 projection along [001] direction, and grew easily at [10] direction. There was no the selective orientation when L12 phase precipitated from the interphase boundary formed by D022 and the disordered matrix. D022 phase had the selective orientation when precipitated from the interphase boundaries of L12, and grew along the [10] direction.

关键词： Microscopic phase-field Atomic-scale Interphase boundary Simulation Ni75AlxV25-x

A robotic laparoscopic tool with enhanced capabilities and modularactuation

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Science China(Technological Sciences) 2019年第1期62卷 47-59页

作者： DAI zhengchen WU ZhongHao ZHAO JiangRan XU Kai The RII Lab(Lab of Robotics Innovation and Intervention) UM-SJTU Joint Institute Shanghai Jiao Tong University State Key Laboratory of Mechanical System and Vibration School of Mechanical Engineering Shanghai Jiao Tong University

Due to the improved treatment outcomes, research on robotic MIS(Minimally Invasive Surgery) thrived in the past decades. A benchmark example is the da Vinci system that dominates robotic laparoscopy via its technology excellence and strong holding of intellectual properties. This study provides an alternative approach to realize robotic laparoscopic surgeries, by presenting the development and experimentation of the SMARLT(Strengthened Modularly Actuated Robotic Laparoscopic Tool) for MIS. A dual continuum mechanism is used in the design to achieve enhanced distal dexterity, improved reliability, increased payload capability, and actuation modularity. With kinematics modelling and actuation compensation, the SMARLT can be manipulated by a generic manipulator to carry out typical laparoscopic MIS tasks, such as tissue peeling, suturing, and knot tying. Payload capability was also experimentally characterized. The SMARLT-manipulator system essentially formed a continuum-rigid hybrid structure that makes full use of the advantages from each component: the continuum mechanism as a wrist for distal dexterity and other rigid parts for position accuracy and payload capability. With the experimental demonstration of the desired functionalities, the SMARLT design can lead to promising opportunities for commercialization.

关键词： dexterous wrist dual continuum mechanism medical robotics modular laparoscopic tools surgical instruments

Self‑Assembly MXene‑rGO/CoNi Film with Massive Continuous Heterointerfaces and Enhanced Magnetic Coupling for Superior Microwave Absorber

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Nano-Micro Letters 2022年第5期14卷 20-33页

作者： Xiao Li zhengchen Wu Wenbin You Liting Yang Renchao Che Laboratory of Advanced Materials Shanghai Key Lab of Molecular Catalysis and Innovative MaterialsFudan UniversityShanghai 200438People’s Republic of China Department of Materials Science Fudan UniversityShanghai 200438People’s Republic of China

MXene, as a rising star of two-dimensional(2 D) materials, has been widely applied in fields of microwave absorption and electromagnetic shielding to cope with the arrival of the 5 G era. However, challenges arise due to the excessively high permittivity and the difficulty of surface modification of few-layered MXenes severely, which infect the microwave absorption performance. Herein, for the first time, a carefully designed and optimized electrostatic selfassembly strategy to fabricate magnetized MXene-r GO/Co Ni film was reported. Inside the synthesized composite film, r GO nanosheets decorated with highly dispersed Co Ni nanoparticles are interclacted into MXene layers, which effectively suppresses the originally self-restacked of MXene nanosheets, resulting in a reduction of high permittivity. In addition, owing to the strong magnetic coupling between the magnetic Fe Co alloy nanoparticles on the r GO substrate, the entire MXener GO/Co Ni film exhibits a strong magnetic loss capability. Moreover, the local dielectric polarized fields exist at the continuous heterointerfaces between 2 D MXene and r GO further improve the capacity of microwave loss. Hence, the synthesized composite film exhibits excellent microwave absorption property with a maximum reflection loss value of-54.1 d B at 13.28 GHz. The electromagnetic synergy strategy is expected to guide future exploration of high-efficiency MXene-based microwave absorption materials.

关键词： MXene Microwave absorption Composite materials Graphene Electron holography

Numerical modeling of the seasonal circulation in the coastal ocean of the Northern South China Sea

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Frontiers of Earth Science 2020年第1期14卷 90-109页

作者： Yang DING Zhigang YAO Lingling ZHOU Min BAO zhengchen ZANG Physical Oceanography Laboratory/CIMST Ocean University of China and Qingdao National Laboratory for Marine Science and TechnologyQingdao 266100China College of Oceanic and Atmospheric Sciences Ocean University of ChinaQingdao 266100China State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyState Oceanic AdministrationHangzhou 310012China Department of Oceanography and Coastal Sciences Louisianan State UniversityBaton RougeLA 70803USA

The Finite Volume Community Ocean Model(FVCOM)was adapted to the Northern South China Sea(NSCS)to investigate the seasonality of coastal circulation,as well as along-shelf and cross-shelf *** fall and winter,southwestward current dominates the NSCS shelf,while the currenfs direction shifts to northeast in *** circulation pattern in spring is more complicated:both southwestward and northeastward currents are detected on the NSCS *** mean shelf circulation pattern in winter does not show the permanent counter-wind South China Sea Warm Current(SCSWC)along the 100-200 m ***,the model results indicate a northeastward current flowing along 50-100 m isobaths in *** along-shelf transport varies from 0.30-1.93 Sv in fall and winter,and it redirects to northeast in summer ranging jfrom 0.44—1.09 *** transport is mainly through the shelf break segment southeast of the Pearl River Estuary.

关键词： Northern South China Sea coastal ocean seasonal circulation along-shelf and cross-shelf transport Ocean model FVCOM

Anti-Phase Relationship Between the East Asian Winter Monsoon and Summer Monsoon During the Holocene?

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Journal of Ocean University of China 2017年第2期16卷 175-183页

作者： GE Qian XUE Zuo YAO Zhigang ZANG zhengchen CHU Fengyou Second Institute of Oceanography State Oceanic AdministrationHangzhou 310012P.R.China Key Laboratory of Submarine Geosciences State Oceanic AdministrationHangzhou 310012P.R.China Department of Oceanography and Coastal Sciences Louisiana State UniversityBaton RougeLA 70803USA Center for Computation and Technology Louisiana State UniversityBaton RougeLA 70803USA Coastal Studies Institute Louisiana State UniversityBaton RougeLA 70803USA Key Laboratory of Physical Oceanography Ocean University of ChinaQingdao 266100P.R.China

The relationship between the East Asian winter monsoon(EAWM) and East Asian summer monsoon(EASM) during the Holocene is complicated and remains *** this study,analysis of grain size and benthic foraminiferal oxygen isotope,as well as accelerator mass spectrometry ^(14)C dating was performed on a sediment core retrieved from the newly revealed muddy deposit on the northern South China Sea continental *** history of the EAWM and EASM were reconstructed for the last 8200 a *** analysis in conjunction with previously published paleo-climate proxies revealed that the relationship between the EAWM and EASM during the Holocene is more complex than a simple and strict anti-phase one-both negative and positive correlations were *** EAWM and EASM are negatively correlated around 7500,4800,4200,3200,and 300 a BP(cooling periods),while positively correlated around 7100,3700,and 2100 a BP(warm periods).In particular,both the EAWM and EASM intensified during the three positive correlation ***,we also found that the relationship between these two sub-monsoons is anti-phase during the final phase of particularly hot periods like Holocene Optimum and Medieval warm *** possible impact from variations of solar irradiance on the relationship between the EAWM and EASM was also discussed.

关键词： grain size oxygen isotope South China Sea East Asian winter monsoon East Asian summer monsoon Holocene

First-principles investigation of the impurity-kink interaction in bcc iron

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Chinese Science Bulletin 2008年第12期53卷 1796-1803页

作者： YU Tao CHEN LiQun WANG ChongYu QIU zhengchen DU JunPing Central Iron and Steel Research Institute Beijing 100081 China College of Sciences Central South University of Forestry and Technology Changsha 410004 China Department of Physics Tsinghua University Beijing 10084 China

Using the first-principles self-consistent discrete variational method based on density functional theory, we investigated the effect of light impurities C and N on the electronic structure of kink on the [100](010) edge dislocation (ED) in bcc iron. Our energetic calculations show that the light impurities have a strong segregation tendency to enter the kink. The results of the charge distribution and the local den-sity of states indicate that the strong bonds between the impurity atoms and the neighboring Fe atoms are formed due to the hybridizations of impurity atoms 2p states and Fe 3d4s4p states. The introduction of light impurities can stabilize the kink system, and impedes the sideward motion of the kink in the [100](010) ED. This is, the light impurities induce a strong pinning effect on the [100](010) ED and may result in the solid solute hardening.

关键词：电子结构交互作用杂质密度泛函理论铁

The impacts of base level and lithology on fluvial geomorphic evolution at the tectonically active Laohu and Hasi Mountains,northeastern Tibetan Plateau

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Science China Earth Sciences 2021年第6期64卷 906-919页

作者： zhengchen LI Xianyan WANG Yang YU Huiping ZHANG Qi SU Xiaodong MIAO Huayu LU School of Geography and Ocean Science Nanjing UniversityNanjing210023China Institute of Geology China Earthquake AdministrationBeijing100029China School of Resource and Environmental Sciences Linyi UniversityLinyi276000China

Previous researches had emphasized tectonic impacts on the fluvial system at the tectonically active areas,while the effects of lithology and local base level change have received relatively rare *** we investigated fluvial landforms at different spatial scales,focusing on knickpoints and channel network reorganization from an area affected by the Haiyuan Fault in the northeastern Tibetan *** geomorphic indices,i.e.,drainage pattern andχanomalies,were calculated and *** results show that two regional radial drainages formed around the Laohu and Hasi *** the interior of the radial drainage,tributaries from the southeast side of the Laohu Mountain experienced near 180°direction *** interpret this as the gradual drainage capture originating from the height difference(~190 m)of the local base level between the two *** tributaries from the Hasi Mountain show alternating gorges and broad valleys controlled by ***,tectonic uplift and the lowering of base level(from the incision of the Yellow River)triggered an autogenic positivefeedback transition from parallel to dendritic drainage *** observations suggest that base level change and lithology play a crucial role in landscape evolution,even in a tectonically active region.

关键词： River piracy Base level Lithology Geomorphic index Haiyuan Fault Northeastern Tibetan Plateau

Maximum and Continuous Wavelength Tuning Ranges of a Grating External- cavity Laser Diode

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Semiconductor Photonics and Technology 1999年第3期5卷 129-133,138页

作者： LUHong－chang zhengchen SchoolofPhysics UniversityofBathBathBA27AYUK Dept.ofComput. UniversityofBradfordBradfordBD71DPU

The wavelength tuning ranges of a grating external-cavity laser diode (ECLD) have been studied by the equivalent cavity method. The maximum tuning range (MTR) and the continuous tuning range (CTR), which are related to the maximum and the minimum threshold carrier densities, are deduced from the threshold condition. We define a ratio of the CTR to the MTR. This ratio is only determined by the reflectivities of the external and internal facets of the ECLD. The analysis shows that there is an appropriate combination of the external and internal-cavity reflectivities to obtain a given CTR in the design of an ECLD.

关键词： External-cavity Laser Diode Reflectivity Tuning CLC number: TN248.4 Document code:A