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Quadratic Dissipation Effect on the Moonpool Resonance

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China Ocean Engineering 2017年第6期31卷 665-673页

作者： LIU Heng-xu CHEN Hai-long zhang Liang zhang Wan-chao LIU Ming College of Shipbuilding Engineering Harbin Engineering University College of Naval Architecture and Ocean Engineering Jiangsu University of Science and Technology

This paper adopted a semi-analytical method based on eigenfunction matching to solve the problem of sharp resonance of cylindrical structures with a moonpool that has a restricted entrance. To eliminate the sharp resonance and to measure the viscous effect, a quadratic dissipation is introduced by assuming an additional dissipative disk at the moonpool entrance. The fluid domain is divided into five cylindrical subdomains, and the velocity potential in each subdomain is obtained by meeting the Laplace equation as well as the boundary conditions. The free-surface elevation at the center of the moonpool, along with the pressure and velocity at the restricted entrance for first-order wave are evaluated. By choosing appropriate dissipation coefficients, the free-surface elevation calculated at the center of the moonpool is in coincidence with the measurements in model tests both at the peak period and amplitude at resonance. It is shown that the sharp resonance in the potential flow theory can be eliminated and the viscous effect can be estimated with a simple method in some provided hydrodynamic models.

关键词： in-fluid quadratic dissipation viscous effect moonpool sharp resonance

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某低品位高铁铝土矿焙烧-碱浸预脱硅试验

有色金属（冶炼部分） 2025年第1期 77-83,118页

作者：张笑天徐璐李超李昃霖杨耀辉徐莺冀成庆中国地质科学院矿产综合利用研究所成都610041 自然资源部战略性矿产综合利用工程技术创新中心成都610041

针对云南某地铝土矿低铝、高硅和高铁的特点,采用焙烧—碱浸预脱硅工艺,获得高铝硅比铝精矿。考察焙烧温度、焙烧时间、碱液Na_(2)O浓度、碱浸时间、液固比对预脱硅效果的影响。在焙烧温度1050℃,焙烧时间30 min,浸出剂Na_(2)O浓度80 g... 详细信息

针对云南某地铝土矿低铝、高硅和高铁的特点,采用焙烧—碱浸预脱硅工艺,获得高铝硅比铝精矿。考察焙烧温度、焙烧时间、碱液Na_(2)O浓度、碱浸时间、液固比对预脱硅效果的影响。在焙烧温度1050℃,焙烧时间30 min,浸出剂Na_(2)O浓度80 g/L,碱浸时间90 min,液固比L/S=8 mL/g的最佳预脱硅条件下,可将低品位铝土矿的铝硅比由4.08提升至17.98,脱硅率高达77.31%,同时预脱硅精矿氧化铝相对溶出率可达94.56%,溶出效果理想。结合热重-示差扫描量热、X射线衍射分析、红外光谱等多种表征手段,分析了焙烧—碱浸预脱硅机理,该铝土矿铝硅比的提高得益于原矿中高岭土类硅酸盐矿物通过焙烧可转化为碱溶性的无定型SiO_(2),采用常压碱浸即可实现铝硅高效分离,获得高铝硅比的铝精矿。

关键词：铝土矿焙烧碱浸预脱硅

Construction of metal chalcogenolate cluster linked organic frameworks

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Chinese Journal of Structural Chemistry 2023年第8期42卷 4-7页

作者： Zhongqi Wu Qian-Feng zhang chao xu Institute of Molecular Engineering and Applied Chemistry Anhui University of TechnologyMa'anshan243002PR China Division of Nanotechnology and Functional Materials Department of Materials Science and EngineeringÅngström LaboratoryUppsala UniversityUppsala75121Sweden

Metal chalcogenide/chalcogenolate clusters(MCCs)are nanoclusters composed of metal and chalcogen ligands,typically containing several to hundreds of metal and chalcogen atoms[1-4].Within these structures,chalcogen ligands(RE^(-)or E^(2-),where R=organic group and E=S,Se,Te)can adopt a variety of bridging coordination modes that connect metal centers into nanoscale *** typically have a well-defined crystal structure,allowing for the study of the structure-properties relationships at the atomic and molecular ***,they usually exhibit unique physicochemical properties that differ from their bulk *** example,the electronic structure and optical properties of MCCs can be precisely tuned by controlling their molecular size,core structure,peripheral organic ligands,and spatial arrangement[5-8].As a result,MCCs are promising materials for applications in energy conversion,sensing,luminescence,and photocatalysis[9-12].

关键词： typically structure cluster

Functional lithiophilic polymer modified separator for dendrite-free and pulverization-free lithium metal batteries

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Journal of Energy Chemistry 2021年第1期30卷 262-268,I0009页

作者： Lingdi Shen Xin Liu Jing Dong Yuting zhang Chunxian xu chao Lai Shanqing zhang School of Chemistry and Materials Science Jiangsu Normal UniversityXuzhou 221116JiangsuChina Center for Clean Environment and energy School of Environment and ScienceGriffith UniversityQueensland 4222Australia

Severe performance drop and fire risk due to the uneven lithium(Li) dendrite formation and growth during charge/discharge process has been considered as the major obstacle to the practical application of Li metal *** inhibiting dendrite growth and producing a stable and robust solid electrolyte interface(SEI) layer are essential to enable the use of Li metal *** this work,a functional lithiophilic polymer composed of chitosan(CTS),polyethylene oxide(PEO),and poly(triethylene glycol dimethacrylate)(PTEGDMA),was homogeneously deposited on a commercial Celgard separator by combining electrospraying and polymer photopolymerization *** lithiophilic environment offered by the CTS-PEO-PTEGDMA layer enables uniform Li deposition and facilitates the formation of a robust homogeneous SEI layer,thus prevent the formation and growth of Li *** a result,both Li/Li symmetric cells and LiFePO4/Li full cells deliver significantly enhanced electrochemical performance and cycle *** after 1000 cycles,the specific capacity of the modified full cell could be maintained at65.8 mAh g^(-1), twice which of the unmodified cell(32.8 mAh g^(-1)).The long-term cycling stability in Li/Li symmetric cells,dendrite-free anodes in SEM images and XPS analysis suggest that the pulverization of the Li anode was effectively suppressed by the lithiophilic polymer layer.

关键词： Lithium metal batteries Functional separators Anode protection Solid electrolyte interface Long cycling life

Byzantine Fault-Tolerant Routing for Large-Scale Wireless Sensor Networks Based on Fast ECDSA

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Tsinghua Science and Technology 2015年第6期20卷 627-633页

作者： Jiawei xu Keda Wang chao Wang Feng Hu Zhenhua zhang Shiyi xu Jie Wu Department of Communication and Information Engineering Shanghai University China Information Security Research Institute Ltd. Huawei Institute of Computer Engineering and Science Shanghai University Department of Computer and Information Sciences Temple University

Wireless sensor networks are a favorite target of Byzantine malicious attackers because of their limited energy, low calculation capability, and dynamic topology, and other important characteristics. The Byzantine Generals Problem is one of the classical problems in the area of fault tolerance, and has wide application, especially in distributed databases and systems. There is a lot of research in agreement and replication techniques that tolerate Byzantine faults. However, most of this work is not suited to large-scale wireless sensor networks, due to its high computational complexity. By introducing Fast ECDSA(Elliptic Curve Digital Signature Algorithm), which can resist timing and energy attacks, and reduce the proportion of verifying signature algorithm to generating signature algorithm to 1.2 times, we propose a new Byzantine fault-tolerant routing algorithm for large-scale wireless sensor networks with double-level hierarchical architecture. In different levels, the algorithm runs different BFT *** and simulation results have proved that this algorithm has high security and the number of communication rounds between clusters is reduced by 1/3, which balances the network load. At the same time, the application of Fast ECDSA improves the security level of the network without burdening it.

关键词： wireless sensor networks Byzantine Generals Proble

A general Boolean semantic modelling approach for complex and intelligent industrial systems in the framework of DES

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Journal of Systems Engineering and Electronics 2024年第5期35卷 1219-1230页

作者： xu Changyi WANG Yun DUAN Yiman zhang chao Key Laboratory of Intelligent Control and Optimization for Industrial Equipment of Ministry of Education School of Control Science and EngineeringDalian University of TechnologyDalian 116024China State Key Laboratory of Fluid Power and Mechatronic Systems School of Mechanical EngineeringZhejiang UniversityHangzhou 310027China

Discrete event system(DES)models promote system engineering,including system design,verification,and *** advancement in manufacturing technology has endowed us to fabricate complex industrial ***,the adoption of advanced modeling methodologies adept at handling complexity and scalability is ***,industrial systems are no longer quiescent,thus the intelligent operations of the systems should be dynamically specified in the *** this paper,the composition of the subsystem behaviors is studied to generate the complexity and scalability of the global system model,and a Boolean semantic specifying algorithm is proposed for generating dynamic intelligent operations in the *** traditional modeling approaches,the change or addition of specifications always necessitates the complete resubmission of the system model,a resource-consuming and error-prone *** with traditional approaches,our approach has three remarkable advantages:(i)an established Boolean semantic can be fitful for all kinds of systems;(ii)there is no need to resubmit the system model whenever there is a change or addition of the operations;(iii)multiple specifying tasks can be easily achieved by continuously adding a new ***,this general modeling approach has wide potential for future complex and intelligent industrial systems.

关键词： industrial complex system operation specifying Boolean semantic discrete event system(DES)theory intelligent operation

Reconstructing Local Volatility Using Total Variation

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Acta Mathematica Sinica,English Series 2017年第2期33卷 263-277页

作者： Rui Yan zhang Fang Fang xu Jian chao HUANG School of Mathematical Sciences University of the Chinese Academy of Sciences College of Mathematics and Systems Science Shandong University of Science and Technology Department of Mathematics Shanghai Jiao Tong University

The aim of this paper is to identify the volatility function in Dupire＇s equation from given option prices. This inverse problem is formulated as an infinite-dimensional minimization problem with PDE constraints. The computational cost of solving the discretized problem on a fine discretization level is expensive. A multi-grid method is proposed to explore the hierarchical structures of discretized problems on different levels. Computational examples are presented to demonstrate the efficiency of our method.

关键词： Volatility smile Dupire's equation finite difference optimization multigrid method

Confidence domain in the stochastic competition chemostat model with feedback control

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Applied Mathematics(A Journal of Chinese Universities) 2018年第4期33卷 379-389页

作者： xu chao-qun YUAN San-ling zhang Tong-hua Faculty of Science Jiangsu University College of Science University of Shanghai for Science and Technology Department of Mathematics Swinburne University of Technology

This paper studies a stochastically forced chemostat model with feedback control in which two organisms compete for a single growth-limiting substrate. In the deterministic counterpart, previous researches show that the coexistence of two competing organisms may be achieved as a stable positive equilibrium or a stable positive periodic solution by different feedback schedules. In the stochastic case, based on the stochastic sensitivity function technique,we construct the confidence domains for different feedback schedules which allow us to find the configurational arrangements of the stochastic attractors and analyze the dispersion of the random states of the stochastic model.

关键词： stochastic chemostat model feedback control white noise confidence domain

Experimental Constraints on Formation of Low-Cr# Chromitite: Effect of Variable H2O and Cr2O3 on Boninitic-Magma and Harzburgite Reactions

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Journal of Earth Science 2020年第4期31卷 709-722页

作者： Yage Zhao Yanfei zhang chao Wang Zhenmin Jin Qijin xu College of Oceanography Hohai UniversityNanjing 210098China State Key Laboratory of Geological Processes and Mineral Resources China University of GeosciencesWuhan 430074China

Reactions between a boninitic or basaltic magma and harzburgite at shallow mantle depths are thought to be closely related to the formation of podiform chromitites,but little experimental data is available on these *** this study,a series of experiments were conducted at 1.5GPa and 1 000–1 400 oC to investigate the interactions between boninitic magma and harzburgite in homogenous mixed systems with varied bulk concentrations of water(~0.7 wt.%–10 wt.%)and Cr2O3(~0.2 wt.%–4 wt.%).In the experimental charges,chromite grains can be observed coexisting with orthopyroxene,clinopyroxene±olivine,and quenched melt in the Cr-bearing *** bulk concentration of Cr2O3 in the starting material has a slight effect on compositional changes in the chromites ***,the Cr#(Cr#=100×Cr/(Cr+Al))and Mg#(Mg#=100×Mg/(Mg+Fe))values for the chromites exhibit positive and negative correlations,respectively,with the bulk H2O *** 1 100 oC,chromite Cr#values range from^33–35 to^58–65,and chromite Mg#values range from^70–73 to^55–58when bulk H2O contents in the starting material are increased from^0.7 wt.%to^10 wt.%.The experimentally produced chromites have compositions(as expressed by Cr#,Mg#,and Ni O and Mn O contents)similar to natural chromites from low-Cr#chromitite *** suggest that the interactions between boninitic magmas with varied H2O contents and harzburgite in a shallow mantle wedge could be a possible mechanism that forms the low-Cr#chromitites found in *** emphasize here that H2O may play an important role in the compositional evolutions of natural chromitites.

关键词： low-Cr#chromitite boninitic magma harzburgite melt-rock reaction