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Regulating Melting Process in the Energy Storage of Solid-Liquid PCM based on Double MRT-LBM Simulation

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Journal of Thermal Science 2024年第5期33卷 1688-1700页

作者： CheN Weiqi SONG Zhichao QUAN dongliang he Yurong School of Energy Science&Engineering Harbin Institute of TechnologyHarbin 150001China heilongjiang Key Laboratory of New Energy Storage Materials and Processes Harbin 150001China Zhengzhou Research Institute of Harbin Institute of Technology Zhengzhou 450000China Innovation&Research Institute of Hiwing Technology Academy Beijing 100074China

The melting process of solid-liquid phase change materials(PCM)has a significant impact on their energy storage *** more effectively apply solid-liquid PCM for energy storage,it is crucial to study the regulation of melting process of solid-liquid PCM,which is numerically investigated based on double multiple relaxation time lattice Boltzmann method(MRT-LBM)in this *** this work we pay more attention to the effects of different Stefan numbers(Ste)and Rayleigh numbers(Ra)on the melting *** results indicate that the PCM melting is greatly influenced by the Ste number and Ra number,which can be divided into the heat conduction dominant stage and the convection dominant stage,according to the onset time of convection Fo_(C).In order to describe the contribution of the heat conduction dominant stage to the whole melting process quantitatively,we firstly propose the ratio of the heat conduction dominant stage R_(pc),which can be defined as the ratio of Fo_(C)to the complete melting time Fo_(M).R_(pc)gradually decreases as the Ra number increases,and when the Ste number rises:R_(pc)=90.0%when Ste=1.0 and Ra=1×10^(5),R_(pc)=39.6%when Ste=0.1 and Ra=1×10^(5),and R_(pc)=14.0%when Ste=1.0 and Ra=1×10~7.A regime map about the effects of different Ste numbers and Ra numbers on R_(pc)has been further *** discovered findings would be helpful in regulating melting process in the energy storage of solid-liquid PCM.

关键词： latent thermal energy storage solid-liquid phase change double MRT-LBM dominant melting mechanism

Junction matters in hydraulic circuit bio-design of microfluidics

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Bio-Design and Manufacturing 2023年第1期6卷 38-50页

作者： Yao Lin dongliang he Zerui Wu Yurou Yao Zhanhao Zhang Yuheng Qiu Shan Wei Guangzhu Shang Xingyue Lei Ping Wu Weiping Ding Liqun he Department of Thermal Science and Energy Engineering University of Science and Technology of ChinaHefei 230027China School of Chemistry and Materials Science University of Science and Technology of ChinaHefei 230027China GeneMind Biosciences Company Limited Shenzhen 518023China Department of Electronic Engineering and Information Science University of Science and Technology of ChinaHefei 230027China

Microfluidic channels are at micrometer scales;thus,their fluid flows are laminar,resulting in the linear dependence of pressure drop on flow rate in the length of the *** ratio of the pressure drop to flow rate,referred to as resistance,depends on channel size and dynamic ***,a microfluidic chip is analogous to an electric circuit in design,but the design is adjusted to optimize channel ***,whereas voltage loss is negligible at the nodes of an electric circuit,hydraulic pressure drops at the nodes of microfluidic chips by a magnitude are comparable to the pressure drops in the straight ***,we prove by experiment that one must fully consider the pressure drops at nodes so as to accurately design a precise microfluidic *** the process,we numerically calculated the pressure drops at hydraulic nodes and list their resistances in the range of flows as *** resorted to machine learning to fit the calculated results for complex ***,we obtained a library of node resistances for common junctions and used them to design three established chips that work for single-cell analysis and for precision allocation of solutes(in gradient and averaging concentration microfluidic networks).Endothelial cells were stimulated by generating concentrations of adriamycin hydrochloride from the last two microfluidic networks,and we analyzed the response of endothelial *** results indicate that consideration of junction resistances in design calculation brings experimental results closer to the design values than *** approach may therefore contribute to providing a platform for the precise design of organ chips.

关键词： Junctions Hydraulics Microfluidic chip design

Broadband high-efficiency dielectric metalenses based on quasi-continuous nanostrips

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Opto-Electronic Advances 2024年第5期7卷 43-51页

作者： Xiaohu Zhang Qinmiao Chen dongliang Tang Kaifeng Liu Haimo Zhang Lintong Shi Mengyao he Yongcai Guo Shumin Xiao Key Laboratory of optoelectronic Technology and Systems of the Education Ministry of China Chongqing UniversityChongqing 400044China Ministry of Industry and Information Technology Key Lab of Micro-Nano Optoelectronic Information System Guangdong Provincial Key Laboratory of Semiconductor Optoelectronic Materials and Intelligent Photonic SystemsHarbin Institute of TechnologyShenzhen 518055China Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education&Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices School of Physics and ElectronicsHunan UniversityChangsha 410082China

Benefiting from the abrupt phase changes within subwavelength thicknesses,metasurfaces have been widely applied for lightweight and compact optical *** broadband and high-efficiency characteristics are highly attractive for the practical implementation of ***,current metasurface devices mostly adopt discrete micro/nano structures,which rarely realize both merits *** this paper,dielectric metasurfaces composed of quasi-continuous nanostrips are proposed to overcome this *** quasi-continuous nanostrips metasurface,a normal focusing metalens and a superoscillatory lens overcoming the diffraction limit are designed and experimentally *** quasi-continuous metadevices can operate in a broadband wavelength ranging from 450 nm to 1000nm and keep a high power *** average efficiency of the fabricated metalens reaches 54.24%,showing a significant improvement compared to the previously reported metalenses with the same *** proposed methodology can be easily extended to design other metadevices with the advantages of broadband and high-efficiency in practical optical systems.

关键词： broadband high-efficiency metalens sub-diffraction quasi-continuous

股权质押违约事件的风险传导——基于股票价格联动的分析

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现代经济探讨 2022年第5期 43-52页

作者：何东良北京大学光华管理学院北京100871

基于2014-2019年中国A股市场上市公司的样本,探究股权质押违约事件是否通过价格联动导致风险传导。研究发现,存在控股股东股权质押的公司在股票价格上呈现显著的联动效应,且股权质押比例越高股价联动水平越高。基于双重差分模型(DID)和... 详细信息

基于2014-2019年中国A股市场上市公司的样本,探究股权质押违约事件是否通过价格联动导致风险传导。研究发现,存在控股股东股权质押的公司在股票价格上呈现显著的联动效应,且股权质押比例越高股价联动水平越高。基于双重差分模型(DID)和倾向评分匹配方法(PSM)的结果显示,股权质押违约事件发生后,未违约的股权质押公司之间的股价联动效应将显著上升,受到了违约事件的风险传导。进一步研究发现,股权质押公司的盈余相关性在违约事件发生后并未显著变化,基本面信息相关性因素不是违约事件提升股价联动效应的原因。投资者有限关注和控股股东持股网络会加剧违约事件后的股价联动,反映出股权质押违约事件导致的市场风险传导是非理性的。

关键词：股权质押风险传导股价联动性有限关注

A numerical model study on the spatial and temporal variabilities of dissolved oxygen in Qinzhou Bay of the northern Beibu Gulf

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Acta Oceanologica Sinica 2024年第6期43卷 49-59页

作者： Gaolei Cheng Shiqiu Peng Bin Yang dongliang Lu State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and TechnologyQingdao 266237China Guangxi Key Laboratory of Marine Environmental Change and Disaster in the Beibu Gulf Beibu Gulf UniversityQinzhou 535011China

Oxygen facilitates the breakdown of the organic material to provide energy for *** concentration of dissolved oxygen(DO) in the water must exceed a certain threshold to support the normal metabolism of marine *** in the northern B eibu Gulf,Qinzhou B ay receives abundant freshwater and nutrients from several rivers which significantly influence the level of the dissolved ***,the spatial-temporal variations of DO as well as the associated driving mechanisms have been rarely studied through field *** this study,a three-dimension al coupled physical-biogeochemical model is used to investigate the spatial and seasonal variations of the DO and the associated driving mechanisms in Qinzhou B *** validation against observations indicates that the model can capture the seasonal and inter-annual variability of the DO concentration with the range of 5-10 mg/*** experiments show that the river discharges,winds and tides play crucial roles in the seasonal variability of the DO by changing the vertical mixing and stratification of the water column and the circulation *** winter,the tide and wind forces have strong effects on the DO distribution by enhancing the vertical mixing,especially near the bay *** summer,the river discharges play a dominant role in the DO distribution by inhibiting the vertical water exchange and delivering more nutrients to the Bay,which increases the DO depletion and results in lower DO on the bottom of the estuary salt *** findings can contribute to the preservation and management of the coastal environment in the northern Beibu Gulf.

关键词： river plume dissolved oxygen stratification physical-biological model

Data-Model Hybrid Driven Topology Identification Framework for Distribution Networks

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CSEE Journal of Power and Energy Systems 2024年第4期10卷 1478-1490页

作者： dongliang Xu Zaijun Wu Junjun Xu Qinran Hu School of Electrical Engineering Southeast UniversityNanjing 210096China College of automation Nanjing University of Posts and TelecommunicationsNanjing 210096China

Extensive penetration of distribution energy resources(DERs)brings increasing uncertainties to distribution *** topology identification is a critical basis to guarantee robust distribution network *** algorithms that estimate distribution network topology have already been ***,most are based on data-driven alone method and are hard to deal with ever-changing distribution network physical *** these backgrounds,this paper proposes a data-model hybrid driven topology identification scheme for distribution ***,a data-driven method based on a deep belief network(DBN)and random forest(RF)algorithm is used to realize the distribution network topology rough ***,the rough identification results in the previous step are used to make a model of distribution network *** model transforms the topology identification problem into a mixed integer programming problem to correct the rough topology *** of the proposed method is verified in an IEEE 33-bus test system and modified 292-bus system.

关键词： Data-model hybrid driven DBN-RF mixed-integer programming topology identification

Effect of icosahedral phase formation on the stress corrosion cracking(SCC)behaviors of the as-cast Mg-8%Li(in wt.%)based alloys

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Journal of Magnesium and Alloys 2024年第1期12卷 225-236页

作者： Shuo Wang Daokui Xu dongliang Wang Zhiqiang Zhang Baojie Wang Key Lab of Electromagnetic Processing of Materials Ministry of EducationNortheastern UniversityShenyang110819China Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang110016China Engineering Research Center of Advanced Materials Preparing Technology Ministry of EducationNortheastern UniversityShenyang110819China School of Environmental and Chemical Engineering Shenyang Ligong UniversityShenyang110159China Binzhou Institute of Technology BinzhouShandong Province256606China Shandong Key Laboratory of Advanced Aluminium Materials and Technology BinzhouShandong Province256606China

Through exploring the stress corrosion cracking(SCC)behaviors of the as-cast Mg-8%Li and Mg-8%Li-6%Zn-1.2%Y alloys in a 0.1 M NaCl solution,it revealed that the SCC susceptibility index(I_(SCC))of the Mg-8%Li alloy was 47%,whilst the I_(SCC)of the Mg-8%Li-6%Zn-1.2%Y alloy was 68%.Surface,cross-sectional and fractography observations indicated that for the Mg-8%Li alloy,theα-Mg/β-Li interfaces acted as the preferential crack initiation sites and propagation paths during the SCC *** regard to the Mg-8%Li-6%Zn-1.2%Y alloy,the crack initiation sites included the I-phase and the interfaces of I-phase/β-Li andα-Mg/β-Li,and the preferential propagation paths were the I-phase/β-Li andα-Mg/β-Li ***,the SCC of the two alloys was concerned with hydrogen embrittlement(he)mechanism.

关键词： Magnesium-lithium alloy Stress corrosion cracking I-phase Fracture analysis

Enhanced photocatalytic performance by regulating the Ce^(3+)/Ce^(4+)ratio in cerium dioxide

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Frontiers of Chemical Science and Engineering 2024年第3期18卷 75-87页

作者： Zhi Li Dongsheng Jia Wei Zhang Ying Li Mitang Wang dongliang Zhang School of Materials and Chemistry University of Shanghai for Science and TechnologyShanghai200093China

Cerium dioxide(CeO_(2))photocatalysts are used in treating environmental pollution and addressing the energy crisis due to their excellent oxygen storage capacities and abundant oxygen *** this paper,CeO_(2)precursors were synthesized with different water-alcohol ratios via a solvothermal method,and CeO_(2)photocatalysts with different Ce^(3+)/Ce^(4+)ratios were obtained by changing the precursor calcination atmospheres(air,Ar)as well as the calcination *** effects of CeO_(2)with different Ce^(3+)/Ce^(4+)ratios in photocatalytic degradations of methylene blue under visible light were investigated.X-ray photoelectron spectroscopy results showed that the surfaces of the samples calcined under Ar had higher Ce^(3+)/Ce^(4+)ratios and oxygen vacancy concentrations,which reduced the band gaps of the catalysts and improved their utilization of visible *** addition,the many Ce^(3+)/Ce^(4+)redox centers and oxygen vacancies on the sample surfaces improved the separation and transfer efficiencies of the photogenerated *** sample C2-Ar calcined under Ar showed a high adsorption capacity and excellent photocatalytic activity by removing 96%of the methylene blue within 120 min,which was more than twice the degradation rate of the sample(C2-air)prepared via calcination under *** experiments showed that photogenerated holes played a key role in the photocatalytic *** addition,a synergistic photocatalytic mechanism for the Ce^(3+)/Ce^(4+)redox centers and oxygen vacancies was elucidated in detail,and the sensitization of cerium dioxide by dyes aided the degradation of methylene blue.

关键词： CeO_(2) oxygen vacancies Ce^(3+)/Ce^(4+)ratios photocatalytic dye-sensitization

Community-detection-based Approaches for Distribution Network Partition

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CSEE Journal of Power and Energy Systems 2024年第5期10卷 1965-1976页

作者： Mingming Mao Zaijun Wu dongliang Xu Junjun Xu Qinran Hu School of Electrical Engineering Southeast UniversityNanjing 210096China State Grid Shanghai Municipal Electric Power Company Pudong Power Supply Company Shanghai 200122China College of Automation and College of Artificial Intelligence Nanjing University of Posts and TelecommunicationsNanjing 210023China

A rational partition is the key prerequisite for the application of distributed algorithms in distribution *** paper proposes community-detection-based approaches to a distribution network partition,including a non-overlapping partition and a border-node partitioning ***,a novel electrical distance is defined to quantify the coupling relationships between buses and it is further used as the edge weight in a transformed equivalent ***,a vertex/link partition community detection approach is applied to over-partition the network into high intra-cohesive and low inter-coupled *** this,a greedy algorithm and a tabu search method are combined to merge these subregions into target numbers according to the scale similarity *** proposed approaches take the influence of three-phase imbalance into consideration and they are decoupled from the power ***,the approaches are tested on an IEEE 123-bus distribution system and the results verify the effectiveness and the credibility of our proposed methods.

关键词： Community detection distribution network partition three-phase imbalance