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基于Surface Evolver模拟液桥断裂距离 被引量:3
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作者 于洋 王学卫 吴群 《医用生物力学》 EI CAS CSCD 2011年第5期436-440,共5页
目的研究面间液桥断裂距离随着液桥体积、球面半径和固-液接触角的变化规律。方法利用SurfaceEvolver程序模拟介于球形表面和平面间一定体积液桥的拉伸、断裂的演变过程,从模拟结果中得到给定液桥体积、球面半径以及固体表面润湿性质这... 目的研究面间液桥断裂距离随着液桥体积、球面半径和固-液接触角的变化规律。方法利用SurfaceEvolver程序模拟介于球形表面和平面间一定体积液桥的拉伸、断裂的演变过程,从模拟结果中得到给定液桥体积、球面半径以及固体表面润湿性质这些参数下的液桥的断裂距离。结果以Lian等和Willett等所给出公式为基础得到液桥断裂距离关于参数液体体积、球面半径和接触角的理论公式,模拟结果与理论预测结果比较,发现当固体表面为亲水性质时,模拟结果与理论结果整体上吻合很好(偏差<4.3%);当固体表面为疏水性质时,模拟结果随着疏水性质的增加与理论估计的偏差会增大。结论 Surface Evolver可以很好地模拟液桥准静态拉伸和断裂过程,从而得到液桥断裂距离。Lian等和Willett等所给出的理论公式是由亲水表面数据拟合出来的,这也是在疏水性质表面上本文所给液桥断裂距离的理论公式预测结果与模拟结果偏差增大的原因。 展开更多
关键词 SURFACE evolver模拟 液桥 断裂距离 拉伸 亲水性 疏水性 生物力学
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微重力状态下自由液面构型的Surface Evolver软件计算 被引量:1
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作者 李永强 叶致君 李利辉 《东北大学学报(自然科学版)》 EI CAS CSCD 北大核心 2016年第9期1364-1368,共5页
以扇柱形贮箱为研究对象,根据微重力状态下液体的毛细现象,基于Surface Evolver软件平台,建立了三维分析模型.利用该模型进行数值模拟,深入研究了微重力状态下扇柱形贮箱内角处自由液面的爬升特性,数值分析结果与实验结果吻合良好,证明... 以扇柱形贮箱为研究对象,根据微重力状态下液体的毛细现象,基于Surface Evolver软件平台,建立了三维分析模型.利用该模型进行数值模拟,深入研究了微重力状态下扇柱形贮箱内角处自由液面的爬升特性,数值分析结果与实验结果吻合良好,证明了该方法的合理有效性.通过数值分析,详细探讨了接触角及容器中心角对微重力条件下自由液面爬升的影响规律,发现液体与容器壁接触角之和小于90°时,液体会不断爬升;当中心角大于50°时,液体爬升高度变化很小. 展开更多
关键词 SURFACE evolver 数值模拟 微重力 自由液面界面 毛细现象
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基于Surface Evolver的小电流CO_2焊熔滴自由过渡的数值模拟
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作者 宋加强 肖珺 +1 位作者 张广军 吴林 《焊接学报》 EI CAS CSCD 北大核心 2013年第5期75-78,98,共5页
为实现小电流CO2焊熔滴自由可控过渡,需对此条件下熔滴的受力状态和临界过渡尺寸及其影响因素进行研究.为此在主要考虑斑点电磁阻力、重力和表面张力的前提下,建立了基于Surface Evolver的CO2焊熔滴形态的数值模型,依据能量最小原理仿... 为实现小电流CO2焊熔滴自由可控过渡,需对此条件下熔滴的受力状态和临界过渡尺寸及其影响因素进行研究.为此在主要考虑斑点电磁阻力、重力和表面张力的前提下,建立了基于Surface Evolver的CO2焊熔滴形态的数值模型,依据能量最小原理仿真获得了静力平衡状态下自由过渡熔滴的形态.进而重点研究了斑点电磁阻力对熔滴过渡临界尺寸的影响.结果表明,电流负脉冲可消除斑点阻力使熔滴由托起状态转为自然下垂,为下一步实现附加外力小电流的熔滴自由过渡提供了依据. 展开更多
关键词 CO2焊 数值模拟 SURFACE evolver软件 熔滴自由过渡 斑点电磁阻力
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基于Surface Evolver的推进剂贮箱气液界面分析 被引量:2
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作者 姜志杰 吴宗谕 +2 位作者 刘常青 黄奕勇 韩伟 《空间科学学报》 CAS CSCD 北大核心 2020年第6期1066-1073,共8页
推进剂贮箱是航天器系统的重要部件,用于实现推进剂的管理与输运.在空间微重力条件下,贮箱内部液面呈弯曲状,掌握其液面分布特性是保证贮箱正常工作的前提.针对球形推进剂贮箱,采用Surface Evolver软件对其内部气液自由界面分布特性展... 推进剂贮箱是航天器系统的重要部件,用于实现推进剂的管理与输运.在空间微重力条件下,贮箱内部液面呈弯曲状,掌握其液面分布特性是保证贮箱正常工作的前提.针对球形推进剂贮箱,采用Surface Evolver软件对其内部气液自由界面分布特性展开研究,分析充液比、接触角、Bond数等参数对贮箱液面的影响,得到液面分布随各参数的变化规律.研究结果表明,球形贮箱液面曲率随充液比的增大而增大,随接触角或Bond数的增大而减小.研究结果有助于实现推进剂贮箱液面快速分析,为贮箱及推进剂管理装置设计提供参考. 展开更多
关键词 推进剂贮箱 气液界面 微重力 SURFACE evolver
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基于能量最小化的CCGA焊点形态仿真研究
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作者 张威 刘坤鹏 +3 位作者 王宏 杭春进 王尚 田艳红 《电子与封装》 2024年第8期51-57,共7页
为了确定某陶瓷柱栅阵列(CCGA)器件实现高焊接可靠性时的工艺参数组合范围,并研究焊点形态随不同参数变化的规律,以钎料润湿角、钎料体积以及焊柱偏移量作为关键变量因素,利用基于能量最小化原理的Surface Evolver软件,计算了不同因素... 为了确定某陶瓷柱栅阵列(CCGA)器件实现高焊接可靠性时的工艺参数组合范围,并研究焊点形态随不同参数变化的规律,以钎料润湿角、钎料体积以及焊柱偏移量作为关键变量因素,利用基于能量最小化原理的Surface Evolver软件,计算了不同因素水平组合下的实际焊点形态,并对参数化建模过程进行了详细介绍。通过对比形态结果与焊点可接收标准,寻找能够产生合格焊点的参量范围,为实际焊点微连接生产工艺提供合理的工艺指导。 展开更多
关键词 封装技术 Surface evolver 焊点形态 CCGA
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PBGA焊点形态对疲劳寿命的影响
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作者 张威 刘坤鹏 +3 位作者 张沄渲 于沐瀛 王尚 田艳红 《电子与封装》 2024年第8期40-46,共7页
通过Surface Evolver软件预测了塑料球栅阵列(PBGA)焊点形态,将焊点形态结果导入Ansys软件中进行-55~125℃热循环仿真实验,通过Coffin-Masson模型预测焊点寿命。选取焊点钎料量、焊点高度、下焊盘直径作为影响焊点寿命的主要因素进行了... 通过Surface Evolver软件预测了塑料球栅阵列(PBGA)焊点形态,将焊点形态结果导入Ansys软件中进行-55~125℃热循环仿真实验,通过Coffin-Masson模型预测焊点寿命。选取焊点钎料量、焊点高度、下焊盘直径作为影响焊点寿命的主要因素进行了3因素3水平正交实验,通过均值响应分析得到了影响凸点寿命的最敏感因素及最优形态尺寸组合。结果表明对焊点寿命影响最大的因素为下焊盘半径,其次是钎料量,最后是焊点高度,且上下等大的焊盘具有较好的可靠性。 展开更多
关键词 Surface evolver 塑料球栅阵列 焊点形态预测 热循环 疲劳寿命 封装技术
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容器内角处流体界面特性与Surface Evolver程序适用性的研究 被引量:1
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作者 徐升华 王林伟 +1 位作者 孙祉伟 王彩霞 《物理学报》 SCIE EI CAS CSCD 北大核心 2012年第16期375-382,共8页
微重力条件下内角处液体行为的研究对于认识表面张力主导的液体行为,预测和控制空间微重力条件下的液体位置、瞬时状态,以及对空间流体进行有效的管理等方面都非常重要.通过分析接触角与流体界面在容器内角处的接触线方向之间的关系,并... 微重力条件下内角处液体行为的研究对于认识表面张力主导的液体行为,预测和控制空间微重力条件下的液体位置、瞬时状态,以及对空间流体进行有效的管理等方面都非常重要.通过分析接触角与流体界面在容器内角处的接触线方向之间的关系,并与Concus-Finn理论进行比较,提出了内角处接触线、接触角和几何形状之间相互关联的机理,并探讨了Concus和Finn等的相关理论结果的物理内涵.在此基础上,进一步将内角处的相关理论结果与SurfaceEvolver程序得出的数值结果进行了比较,指出当容器中的内角小于180°时,SurfaceEvolver程序通过自动划分网格即可比较准确地预言内角处的接触线和液面行为,但是当内角大于180°时,自动划分网格得到的数值结果有较大的误差,需要通过手动划分网格减少网格奇异才能减小误差.因此,对于具有复杂几何形状的容器,需注意网格的奇异性,并对内角处的液面进行定量的验证,才能有效判断Surface Evolver程序结果的正确性.本工作对于深入认识内角处的液面特性和机理,理解Surface Evolver程序的适用条件,以及分析微重力条件下容器内角处的液体行为等方面都具有明显意义. 展开更多
关键词 接触线 接触角 内角 SURFACE evolver
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Co-pyrolysis of Sewage Sludge with Distillation Residue: Kinetics Analysis via Iso-conversional Methods
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作者 ZHOU Shangqun ZHAO Qinglin +1 位作者 YU Tian YAO Xiaojie 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第5期1188-1198,共11页
This study explored the synergistic interaction of sewage sludge(SS)and distillation residue(DR)during co-pyrolysis for the optimized treatment of sewage sludge in cement kiln systems,utilizing thermogravimetric analy... This study explored the synergistic interaction of sewage sludge(SS)and distillation residue(DR)during co-pyrolysis for the optimized treatment of sewage sludge in cement kiln systems,utilizing thermogravimetric analysis(TGA)and thermogravimetric analysis with mass spectrometry(TGA-MS).The results reveal the coexisting synergistic and antagonistic effects in the co-pyrolysis of SS/DR.The synergistic effect arises from hydrogen free radicals in SS and catalytic components in ash fractions,while the antagonistic effect is mainly due to the melting of DR on the surface of SS particles during pyrolysis and the reaction of SS ash with alkali metals to form inert substances.SS/DR co-pyrolysis reduces the yielding of coke and gas while increasing tar production.This study will promote the reduction,recycling,and harmless treatment of hazardous solid waste. 展开更多
关键词 sewage sludge CO-PYROLYSIS distillation residue KINETICS evolved gas analysis
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Role of fullerenols derivative 3HFWC in the treatment of Alzheimer's disease
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作者 Sanja Ivkovic Djuro Koruga 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第8期1641-1642,共2页
Fullerenes:The extensive development of nanoscience that has marked this century continues to evolve,producing new materials,structures,and devices for the treatments of diverse pathologies.Fullerenes are a family of ... Fullerenes:The extensive development of nanoscience that has marked this century continues to evolve,producing new materials,structures,and devices for the treatments of diverse pathologies.Fullerenes are a family of nanoparticles with great applicative promise due to their small size(approximately 1 nm in diameter),structure,and capacity to cross biological barriers. 展开更多
关键词 TREATMENT evolve SIZE
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Co-pyrolysis of Sewage Sludge with Paint Sludge: Kinetics and Thermodynamic Analysis via Iso-conversional Methods
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作者 周尚群 赵青林 +1 位作者 YU Tian YAO Xiaojie 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第3期716-727,共12页
This study explored the synergistic interaction of sewage sludge(SS)and automotive paint sludge(PS)during co-pyrolysis for the optimized treatment of sewage sludge in cement kiln systems,utilizing thermogravimetric an... This study explored the synergistic interaction of sewage sludge(SS)and automotive paint sludge(PS)during co-pyrolysis for the optimized treatment of sewage sludge in cement kiln systems,utilizing thermogravimetric analysis(TGA)and thermogravimetric-mass spectrometry(TGA-MS).The result reveals the coexisting synergistic and antagonistic effects in the co-pyrolysis of SS/PS.The synergistic effect arises from hydrogen free radicals in SS and catalytic components in PS,while the main source of the antagonistic effect is that,during the mechanical mixing process,the SS/PS is converted from the particulate form into a dough-like rubbery which contributes to the film-forming effect,hindering the volatilization of volatile components.SS/PS co-pyrolysis reduces the yielding of tar production while increasing coke and gas.This study will provide some in-depth insights into the co-pyrolysis of SS/PS,and offer theoretical support for the subsequent research on the collaborative disposal processes in cement kilns. 展开更多
关键词 sewage sludge CO-PYROLYSIS automotive paint sludge evolved gas analysis
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Ultrathin Limit on the Anisotropic Superconductivity of Single-Layered Cuprate Films
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作者 冉峰 陈潘 +5 位作者 李丁艺 熊沛雨 樊子鑫 凌浩铭 梁艳 张坚地 《Chinese Physics Letters》 SCIE EI CAS CSCD 2024年第2期94-101,共8页
Exploring dimensionality effects on cuprates is important for understanding the nature of high-temperature superconductivity.By atomically layer-by-layer growth with oxide molecular beam epitaxy,we demonstrate that La... Exploring dimensionality effects on cuprates is important for understanding the nature of high-temperature superconductivity.By atomically layer-by-layer growth with oxide molecular beam epitaxy,we demonstrate that La_(2−x)Sr_(x)CuO_(4)(x=0.15)thin films remain superconducting down to 2 unit cells of thickness but quickly reach the maximum superconducting transition temperature at and above 4 unit cells.By fitting the critical magnetic field(μ0H_(c2)),we show that the anisotropy of the film’s superconductivity increases with decreasing film thickness,indicating that the superconductivity of the film gradually evolves from weak three-to two-dimensional character.These results are helpful to gain more insight into the nature of high-temperature superconductivity with dimensionality. 展开更多
关键词 dimensionality FILM evolve
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Genetic mechanism of body size variation in groupers:Insights from phylotranscriptomics
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作者 Wei-Wei Zhang Zhuo-Ying Weng +5 位作者 Xi Wang Yang Yang Duo Li Le Wang Xiao-Chun Liu Zi-Ning Meng 《Zoological Research》 SCIE CSCD 2024年第2期314-328,共15页
Animal body size variation is of particular interest in evolutionary biology,but the genetic basis remains largely unknown.Previous studies have shown the presence of two parallel evolutionary genetic clusters within ... Animal body size variation is of particular interest in evolutionary biology,but the genetic basis remains largely unknown.Previous studies have shown the presence of two parallel evolutionary genetic clusters within the fish genus Epinephelus with evident divergence in body size,providing an excellent opportunity to investigate the genetic basis of body size variation in vertebrates.Herein,we performed phylotranscriptomic analysis and reconstructed the phylogeny of 13 epinephelids originating from the South China Sea.Two genetic clades with an estimated divergence time of approximately 15.4 million years ago were correlated with large and small body size,respectively.A total of 180 rapidly evolving genes and two positively selected genes were identified between the two groups.Functional enrichment analyses of these candidate genes revealed distinct enrichment categories between the two groups.These pathways and genes may play important roles in body size variation in groupers through complex regulatory networks.Based on our results,we speculate that the ancestors of the two divergent groups of groupers may have adapted to different environments through habitat selection,leading to genetic variations in metabolic patterns,organ development,and lifespan,resulting in body size divergence between the two locally adapted populations.These findings provide important insights into the genetic mechanisms underlying body size variation in groupers and species differentiation. 展开更多
关键词 Phylotranscriptomics GROUPER Body size Rapidly evolving genes(REGs) Positively selected genes(PSGs)
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Position-Aware and Subgraph Enhanced Dynamic Graph Contrastive Learning on Discrete-Time Dynamic Graph
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作者 Jian Feng Tian Liu Cailing Du 《Computers, Materials & Continua》 SCIE EI 2024年第11期2895-2909,共15页
Unsupervised learning methods such as graph contrastive learning have been used for dynamic graph represen-tation learning to eliminate the dependence of labels.However,existing studies neglect positional information ... Unsupervised learning methods such as graph contrastive learning have been used for dynamic graph represen-tation learning to eliminate the dependence of labels.However,existing studies neglect positional information when learning discrete snapshots,resulting in insufficient network topology learning.At the same time,due to the lack of appropriate data augmentation methods,it is difficult to capture the evolving patterns of the network effectively.To address the above problems,a position-aware and subgraph enhanced dynamic graph contrastive learning method is proposed for discrete-time dynamic graphs.Firstly,the global snapshot is built based on the historical snapshots to express the stable pattern of the dynamic graph,and the random walk is used to obtain the position representation by learning the positional information of the nodes.Secondly,a new data augmentation method is carried out from the perspectives of short-term changes and long-term stable structures of dynamic graphs.Specifically,subgraph sampling based on snapshots and global snapshots is used to obtain two structural augmentation views,and node structures and evolving patterns are learned by combining graph neural network,gated recurrent unit,and attention mechanism.Finally,the quality of node representation is improved by combining the contrastive learning between different structural augmentation views and between the two representations of structure and position.Experimental results on four real datasets show that the performance of the proposed method is better than the existing unsupervised methods,and it is more competitive than the supervised learning method under a semi-supervised setting. 展开更多
关键词 Dynamic graph representation learning graph contrastive learning structure representation position representation evolving pattern
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Spatial-temporal distribution and geochemistry of highly evolved Mesozoic granites in Great Xing’an Range,NE China:Discriminant criteria and geological significance
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作者 WU Haoran YANG Hao +4 位作者 GE Wenchun JI Zheng DONG Yu JING Yan JING Jiahao 《Global Geology》 2024年第1期20-34,共15页
Highly evolved granite is an important sign of the mature continent crust and closely associated with deposits of rare metals.In this work,the authors undertake systematically zircon U-Pb ages and whole rock elemental... Highly evolved granite is an important sign of the mature continent crust and closely associated with deposits of rare metals.In this work,the authors undertake systematically zircon U-Pb ages and whole rock elemental data for highly evolved granitic intrusions from the Great Xing’an Range(GXR),NE China,to elucidate their discriminant criteria,spatial-temporal distribution,differentiation and geodynamic mecha-nism.Geochemical data of these highly evolved granites suggest that high w(SiO_(2))(>70%)and differentiation index(DI>88)could be quantified indicators,while strong Eu depletion,high TE_(1,3),lowΣREE and low Zr/Hf,Nb/Ta,K/Rb could only be qualitative indicators.Zircon U-Pb ages suggest that the highly evolved gran-ites in the GXR were mainly formed in Late Mesozoic,which can be divided into two major stages:Late Ju-rassic-early Early Cretaceous(162-136 Ma,peak at 138 Ma),and late Early Cretaceous(136-106 Ma,peak at 126 Ma).The highly evolved granites are mainly distributed in the central-southern GXR,and display a weakly trend of getting younger from northwest to southeast,meanwhile indicating the metallogenic potential of rare metals within the central GXR.The spatial-temporal distribution,combined with regional geological data,indicates the highly evolved Mesozoic granites in the GXR were emplaced in an extensional environ-ment,of which the Late Jurassic-early Early Cretaceous extension was related to the closure of the Mongol-Okhotsk Ocean and roll-back of the Paleo-Pacific Plate,while the late Early Cretaceous extension was mainly related to the roll-back of the Paleo-Pacific Plate. 展开更多
关键词 highly evolved granite Great Xing’an Range spatial-temporal distribution extensional environment
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Closer Trade Ties:An Engine for Economic Growth
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作者 Chiang Hee Tze 《China Report ASEAN》 2024年第6期54-55,共2页
The origins of Malaysia-China ties can be traced back to ancient trade of goods.Throughout history,the bilateral relationship has endured ebbs and flows to evolve into full-fledged diplomatic and economic interactions... The origins of Malaysia-China ties can be traced back to ancient trade of goods.Throughout history,the bilateral relationship has endured ebbs and flows to evolve into full-fledged diplomatic and economic interactions.This evolution reflects changes in Southeast Asian and global landscapes,which have been heavily influenced by post-World War II realignment,Cold War politics,and the rise of China. 展开更多
关键词 LANDSCAPE ENGINE evolve
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Design of an Interconnection Architecture and Sizing of Two (2) EPC Core Networks: The Case of Orange-Guinea
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作者 Mamadou Sadigou Diallo Kadiatou Aissatou Barry +4 位作者 Amadou Lamarana Bah Mamadou Sanoussy Camara Janvier Fotsing Amadou Barry Amadou Oury Bah 《Journal of Energy and Power Engineering》 CAS 2024年第2期59-70,共12页
With the arrival of the 4G and 5G,the telecommunications networks have experienced a large expansion of these networks.That enabled the integration of many services and adequate flow,thus enabling the operators to res... With the arrival of the 4G and 5G,the telecommunications networks have experienced a large expansion of these networks.That enabled the integration of many services and adequate flow,thus enabling the operators to respond to the growing demand of users.This rapid evolution has given the operators to adapt,their methods to the new technologies that increase.This complexity becomes more important,when these networks include several technologies to access different from the heterogeneous network like in the 4G network.The dimensional new challenges tell the application and the considerable increase in demand for services and the compatibility with existing networks,the management of mobility intercellular of users and it offers a better quality of services.Thus,the proposed solution to meet these new requirements is the sizing of the EPC(Evolved Packet Core)core network to support the 5G access network.For the case of Orange Guinea,this involves setting up an architecture for interconnecting the core networks of Sonfonia and Camayenne.The objectives of our work are of two orders:(1)to propose these solutions and recommendations for the heart network EPC sizing and the deployment to be adopted;(2)supply and architectural interconnection in the heart network EPC and an existing heart network.In our work,the model of traffic in communication that we use to calculate the traffic generated with each technology has link in the network of the heart. 展开更多
关键词 5G network 4G network(EPS(evolved packet system)) 3G network(UMTS:Universal Mobile Telecommunications System) EPC network of the heart architecture dimensional Orange Guinea technology service
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英国高中地理教材栏目设置的特点及启示——以Geography B Evolving Planet为例
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作者 徐波 安龙 +3 位作者 袁圆 欧然然 谢庆玲 冯婷 《咸阳师范学院学报》 2023年第4期84-88,共5页
以英国中学地理教材Geography B Evolving Planet中的教材栏目为研究对象,结合其在教材中实际发挥的功能,将八种主要的教材栏目划分为问题思考类、技能训练类、信息提示类和考试导向类四大类。这四大类教材栏目体现出了不同的特点。问... 以英国中学地理教材Geography B Evolving Planet中的教材栏目为研究对象,结合其在教材中实际发挥的功能,将八种主要的教材栏目划分为问题思考类、技能训练类、信息提示类和考试导向类四大类。这四大类教材栏目体现出了不同的特点。问题思考类栏目指向不同教学目标,技能训练类栏目凸显实用性和应用性的学科特色,信息提示类栏目关注学生心理特点,考试导向类栏目提高应试答题技巧。受此启发,未来我国中学地理教材栏目设置应有所侧重,即教材栏目在内容设置上要注重针对性,在形式设置上要增加多样性,在外观设置上要注重醒目性。 展开更多
关键词 地理教材 Geography B Evolving Planet 教材栏目
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Editorial:Driving into Future with Reliable,Secure,Efficient and Intelligent MetaVehicles
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作者 Qing-Long Han 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2023年第6期1355-1356,共2页
Welcome to the sixth issue of the IEEE/CAA Journal of Automatica Sinica(JAS)in 2023!In the first issue in 2023,I briefly discussed about MetaVehicles,a technological expression of intelligent vehicles,robotics,AI,bloc... Welcome to the sixth issue of the IEEE/CAA Journal of Automatica Sinica(JAS)in 2023!In the first issue in 2023,I briefly discussed about MetaVehicles,a technological expression of intelligent vehicles,robotics,AI,blockchain,knowledge automation,networking and communication[1].As the concept of the Metaverse continues to evolve and expand,the range of vehicle entities is diversely enlarged,including passenger vehicles,heavy duty vehicles,rail vehicles,marine vehicles,aerial vehicles,and other types of transportation.The development and use of MetaVehicles are likely to become more sophisticated.Therefore,from a systems and control perspective,new methods of control,estimation and optimization should be developed to achieve the improved vehicular control system stability and reliability in the physical space. 展开更多
关键词 estimation LIKELY evolve
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Subspace Clustering in High-Dimensional Data Streams:A Systematic Literature Review
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作者 Nur Laila Ab Ghani Izzatdin Abdul Aziz Said Jadid AbdulKadir 《Computers, Materials & Continua》 SCIE EI 2023年第5期4649-4668,共20页
Clustering high dimensional data is challenging as data dimensionality increases the distance between data points,resulting in sparse regions that degrade clustering performance.Subspace clustering is a common approac... Clustering high dimensional data is challenging as data dimensionality increases the distance between data points,resulting in sparse regions that degrade clustering performance.Subspace clustering is a common approach for processing high-dimensional data by finding relevant features for each cluster in the data space.Subspace clustering methods extend traditional clustering to account for the constraints imposed by data streams.Data streams are not only high-dimensional,but also unbounded and evolving.This necessitates the development of subspace clustering algorithms that can handle high dimensionality and adapt to the unique characteristics of data streams.Although many articles have contributed to the literature review on data stream clustering,there is currently no specific review on subspace clustering algorithms in high-dimensional data streams.Therefore,this article aims to systematically review the existing literature on subspace clustering of data streams in high-dimensional streaming environments.The review follows a systematic methodological approach and includes 18 articles for the final analysis.The analysis focused on two research questions related to the general clustering process and dealing with the unbounded and evolving characteristics of data streams.The main findings relate to six elements:clustering process,cluster search,subspace search,synopsis structure,cluster maintenance,and evaluation measures.Most algorithms use a two-phase clustering approach consisting of an initialization stage,a refinement stage,a cluster maintenance stage,and a final clustering stage.The density-based top-down subspace clustering approach is more widely used than the others because it is able to distinguish true clusters and outliers using projected microclusters.Most algorithms implicitly adapt to the evolving nature of the data stream by using a time fading function that is sensitive to outliers.Future work can focus on the clustering framework,parameter optimization,subspace search techniques,memory-efficient synopsis structures,explicit cluster change detection,and intrinsic performance metrics.This article can serve as a guide for researchers interested in high-dimensional subspace clustering methods for data streams. 展开更多
关键词 CLUSTERING subspace clustering projected clustering data stream stream clustering high dimensionality evolving data stream concept drift
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基于PDMS和玻璃材料的毛细管被动阀临界压力分析 被引量:7
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作者 杜新 张平 +1 位作者 刘永顺 吴一辉 《光学精密工程》 EI CAS CSCD 北大核心 2011年第8期1852-1858,共7页
针对现有的数值仿真方法不能够准确地计算矩形截面毛细阀用亲水性很好的玻璃作盖板时的临界压力,提出了一种分析复合壁面毛细管被动阀临界压力的方法。使用Surface Evolver(SE)自由软件,通过设置和实际流动相符的边界条件,并监测在扩张... 针对现有的数值仿真方法不能够准确地计算矩形截面毛细阀用亲水性很好的玻璃作盖板时的临界压力,提出了一种分析复合壁面毛细管被动阀临界压力的方法。使用Surface Evolver(SE)自由软件,通过设置和实际流动相符的边界条件,并监测在扩张段入口处接触角的变化范围,实现了对由玻璃盖板和PDMS微通道构成的被动阀的临界压力的计算。此时,接触线应该设置为可以进入到扩张段的侧壁上,而不能固定在扩张段入口处。对于深度为25μm,宽深比为2,4,8,16的毛细管被动阀,得到的临界压力分别为0.77,0.45,0.33,0.24 kPa。仿真结果和转台实验结果基本相符,证实了SE方法的有效性。文中分析了接触角对毛细阀有效性的影响,指出当通道和平板材料的接触角之和大于90°时,毛细阀才能控制流动。 展开更多
关键词 微流体 毛细阀 附加压力 SURFACE evolver
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