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Water Science and Engineering 2024年第2期17卷 129-138页

作者： Guo-fen Hua Shang-qing Liu xiang-dong Liu Jin-li Li Yue Fang Wen-ting Xie xiang Xu College of Water Conservancy and Hydroelectric Power Hohai UniversityNanjing 210098China College of Renewable Energy Hohai UniversityNanjing 210098China

Coastal wetlands are hotspots for nitrogen(N)cycling,and crab burrowing is known to transform N in intertidal marsh ***,the underlying mechanisms remain *** study conducted field experiments and used indoor control test devices to investigate the seasonal response of nitrogen to crab disturbance at the sediment-water interface in coastal tidal flat *** results showed that crab disturbance exhibited significant seasonality with large seasonal differences in cave density and *** to crab disturbance,nitrogen fuxes at the sediment-water interface were much greater in the box with crabs than in the box without *** summer,NH-N showed a positive flux from the sediment to the overlying water,but NO2-N and NOg-N showed positive fluxes from the sediment to the overlying water only in early *** winter,NH-N showed a positive flux from the sediment to the overlying water,but NO-N and NO,-N both exhibited positive and negative *** results indicated that the presence of crab burrows can cause the aerobic layer to move downward by approximately 8-15 cm in summer and directly promote nitrification at the sediment surface.

关键词： Coastal tidal flat wetland Crab disturbance Nitrogen flux Nitrification Denitrification Sediment-water interface

Capacity Market Mechanism Design,Considering Network Optimization and Energy Transition

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CSEE Journal of Power and Energy Systems 2024年第4期10卷 1676-1687页

作者： Nan Shang Yihang Song xiang Zhang You Lin China Southern Power Grid Co. Ltd.Guangzhou 510663China Southern Methodist University Junkins 3086251 Airline Road DallasTX 75205US

The coordination of enrgy transition,fixed cost recovery,and sufficient generation supply leads to a new challenge for a traditional capacity market ***,in order to better match network expansion at the same time,it is crucial to redesign the capacity market mechanism considering system *** this paper,a novel capacity market mechanism is proposed considering spot market operations,network expansion,and energy transition,which can minimize the total cost of capacity investment,network expansion,and generation operations,while satisfying the energy transition constraints and topology ***,the capacity market mechanism co-ordinated with spot market operations is illustrated,in which the energy transition and network constraints are ***,a bi-level optimization model is established where the trade organizers minimize the total cost of both investment and operations,subject to the spot power market simultaneously minimizing the local dispatching *** numerical results of a test system show that more economical capacity portfolios can be obtained by constructing reasonable transmission lines,thereby obtaining a more optimal market cost.A detailed multi-scenario simulation is further analyzed to verify the effectiveness of the proposed market mechanism.

关键词： Capacity market energy transition network expansion spot market operation

A Novel Fall Detection Framework Using Skip-DSCGAN Based on Inertial Sensor Data

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Computers, Materials & Continua 2024年第1期78卷 493-514页

作者： Kun Fang Julong Pan Lingyi Li Ruihan xiang College of Information Engineering China Jiliang UniversityHangzhou310018China

With the widespread use of Internet of Things(IoT)technology in daily life and the considerable safety risks of falls for elderly individuals,research on IoT-based fall detection systems has gainedmuch *** paper proposes an IoT-based spatiotemporal data processing framework based on a depthwise separable convolution generative adversarial network using skip-connection(Skip-DSCGAN)for fall *** method uses spatiotemporal data from accelerometers and gyroscopes in inertial sensors as input data.A semisupervised learning approach is adopted to train the model using only activities of daily living(ADL)data,which can avoid data imbalance ***,a quantile-based approach is employed to determine the fall threshold,which makes the fall detection frameworkmore *** proposed fall detection framework is evaluated against four other generative adversarial network(GAN)models with superior anomaly detection performance using two fall public datasets(SisFall&MobiAct).The test results show that the proposed method achieves better results,reaching 96.93% and 92.75% accuracy on the above two test datasets,*** the same time,the proposed method also achieves satisfactory results in terms ofmodel size and inference delay time,making it suitable for deployment on wearable devices with limited *** addition,this paper also compares GAN-based semisupervised learning methods with supervised learning methods commonly used in fall *** clarifies the advantages of GAN-based semisupervised learning methods in fall detection.

关键词： Fall detection skip-connection depthwise separable convolution generative adversarial networks inertial sensor

The Completeness of Accreting Neutron Star Binary Candidates from the Chinese Space Station Telescope

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Research in Astronomy and Astrophysics 2024年第9期24卷 28-36页

作者： Hao Shen Shun-Yi Lan xiang-Cun Meng Yunnan Observatories Chinese Academy of SciencesKunming 650216China University of Chinese Academy of Sciences Beijing 100049China International Centre of Supernovae Yunnan Key LaboratoryKunming 650216China

A neutron star(NS)has many extreme physical conditions,and one may obtain some important information about an NS via accreting neutron star binary(ANSB)*** upcoming Chinese Space Station Telescope(CSST)provides an opportunity to search for a large sample of ANSB *** goal is to check the completeness of the potential ANSB samples from CSST *** this paper,we generate some ANSBs and normal binaries under the CSST photometric system by binary evolution and binary population synthesis method and use a machine learning method to train a classification *** the Precision(94.56%)of our machine learning model is as high as before study,the Recall is only about 63.29%.The Precision/Recall is mainly determined by the mass transfer rate between the NSs and their *** addition,we also find that the completeness of ANSB samples from CSST photometric data by the machine learning method also depends on the companion mass and the age of the *** candidates with a low initial mass companion star(0.1 M_(⊙)to 1 M_(⊙))have a relatively high Precision(94.94%)and high Recall(86.32%),whereas ANSB candidates with a higher initial mass companion star(1.1 M_(⊙)to 3 M_(⊙))have similar Precision(93.88%)and quite low Recall(42.67%).Our results indicate that although the machine learning method may obtain a relatively pure sample of ANSBs,a completeness correction is necessary for one to obtain a complete sample.

关键词： stars:neutron X-rays:binaries methods:analytical

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Assessing the dynamics of O2 desorption from cobalt phthalocyanine by in situ electrochemical scanning tunneling microscopy

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Journal of Energy Chemistry 2024年第11期98卷 144-148页

作者： Yu-Qi Wang Yue Feng xiang Wang Dong Wang CAS Key Laboratory of Molecular Nanostructure and Nanotechnology CAS Research/Education Center for Excellence in Molecular Sciences Beijing National Laboratory for Molecular Science (BNLMS) Institute of Chemistry Chinese Academy of Sciences University of Chinese Academy of Sciences

We report here the in situ electrochemical scanning tunneling microscopy（ECSTM） study of cobalt phthalocyanine（CoPc）-catalyzed O2evolution reaction（OER） and the dynamics of *** self-assembled CoPc monolayer is fabricated on Au（111） substrate and resolved by ECSTM in 0.1 M KOH *** OH-adsorption on CoPc prior to OER is observed in ECSTM *** OER,the generated O2adsorbed on Co Pc is observed in the CoPc *** step experiment is employed to monitor the desorption of OER-generated O2from CoPc,which results in the decreasing surface coverage of CoPc-O2with *** rate constant of O2desorption is evaluated through data *** insights into the dynamics of Co-O2dissociation at the molecular level via in situ imaging help understand the role of Co-O2in oxygen reduction reaction（ORR） and OER.

关键词： Cobalt phthalocyanine Electrochemical scanning tunneling microscopy Oxygen evolution reaction

Exploring multiple phases and first-order phase transitions in Kármán Vortex Street

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Science China(Physics,Mechanics & Astronomy) 2024年第11期67卷 47-54页

作者： Xu Li Xing xiang Tingting Xue Limin Wang Xiaosong Chen School of Systems Science and Institute of Nonequilibrium Systems Beijing Normal UniversityBeijing 100875China State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy ofSciencesBeijing 100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China

Kármán Vortex Street, a fascinating phenomenon of fluid dynamics, has intrigued the scientific community for a long time. Many researchers have dedicated their efforts to unraveling the essence of this intriguing flow pattern. Here, we apply the lattice Boltzmann method with curved boundary conditions to simulate flows around a circular cylinder and study the emergence of Kármán Vortex Street using the eigen microstate approach, which can identify phase transition and its order-parameter. At low Reynolds number, there is only one dominant eigen microstate W_(1) of laminar flow. At Re_(c)^(1)= 53.6, there is a phase transition with the emergence of an eigen microstate pair W^(2,3) of pressure and velocity fields. Further at Re_(c)^(2)= 56, there is another phase transition with the emergence of two eigen microstate pairs W^(4,5) and W^(6,7). Using the renormalization group theory of eigen microstate,both phase transitions are determined to be first-order. The two-dimensional energy spectrum of eigen microstate for W^(1), W^(2,3) after Re_(c)^(1), W^(4-7) after Re_(c)^(2) exhibit-5/3 power-law behavior of Kolnogorov's K41 theory. These results reveal the complexity and provide an analysis of the Kármán Vortex Street from the perspective of phase transitions.

关键词： Kármán Vortex Street first-order phase transition eigen microstate approach renormalization group theory of eigen microstate

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Toward a fundamental understanding of the heterogeneous multiphysics behaviors of silicon monoxide/graphite composite anodes

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Carbon Energy 2024年第1期6卷 142-158页

作者： xiang Gao Suli Li Jiachen Xue Dianyang Hu Jun Xu Department of Mechanical Engineering and Engineering Science University of North Carolina at CharlotteCharlotteNorth CarolinaUSA Vehicle Energy and Safety Laboratory(VESL) Battery ComplexityAutonomous Vehicleand Electrification(BATT CAVE)Research CenterUniversity of North Carolina at CharlotteCharlotteNorth CarolinaUSA Zhuhai CosMX Battery Co.Ltd. ZhuhaiGuangdongChina School of Data Science University of North Carolina at CharlotteCharlotteNorth CarolinaUSA

Silicon monoxide(SiO)(silicon[Si]mixed with silicon dioxide[SiO_(2)])/graphite(Gr)composite material is one of the most commercially promising anode materials for the next generation of high-energy-density lithium-ion *** major bottleneck for SiO/Gr composite anode is the poor cyclability arising from the stress/strain behaviors due to the mismatch between two heterogenous materials during the lithiation/delithiation *** date,a meticulous and quantitative understanding of the highly nonlinear coupling behaviors of such materials is still ***,an electro–chemo–mechanics-coupled detailed model containing particle geometries is *** underlying mechanism of the regulation between SiO and Gr components during electrochemical cycling is quantitatively *** discover that increasing the SiO weight percentage(wt%)reduces the utilization efficiency of the active materials at the same 1C rate charging and enhances the hindering effects of stress-driven flux on *** addition,the mechanical constraint demonstrates a balanced effect on the overall performance of cells and the local behaviors of *** study provides new insights into the fundamental interactions between SiO and Gr materials and advances the investigation methodology for the design and evaluation of next-generation high-energydensity batteries.

关键词： interactions lithium-ion batteries mechanical constraint multiphysics modeling Si-based anode

Crystal structure,phase transitions,and thermodynamic properties of magnesium metavanadate(MgV_(2)O_(6))

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Journal of Magnesium and Alloys 2024年第4期12卷 1449-1460页

作者： Guishang Pei Cheng Pan Dapeng Zhong Junyi xiang Xuewei Lv College of Materials Science and Engineering Chongqing UniversityChongqing 400044China Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and Advanced Materials Chongqing UniversityChongqing 400044China Pangang Group Research Institute Co. Ltd.Panzhihua 617000China

As a promising anode material for magnesium ion rechargeable batteries,magnesium metavanadate(MgV_(2)O_(6))has attracted considerable research interest in recent years.A MgV_(2)O_(6)sample was synthesized via a facile solid-state reaction by multistep-firing stoichiometric mixtures of MgO and V2O5 powder under an air *** solid-state phase transition fromα-MgV_(2)O_(6)toβ-MgV_(2)O_(6)occurred at 841 K and the enthalpy change was 4.37±0.04 kJ/*** endothermic effect at 1014 K and the enthalpy change was 26.54±0.26 kJ/mol,which is related to the incongruent melting ofβ-MgV_(2)O_(6).In situ XRD was performed to investigate phase transition of the as-prepared MgV_(2)O_(6)at high *** cell parameters obtained by Rietveld refinement indicated that it crystallizes in a monoclinic system with the C2/m space group,and the lattice parameters of a=9.280 A°,b=3.501 A°,c=6.731 A°,β=111.76°.The solid-state phase transition fromα-MgV_(2)O_(6)toβ-MgV_(2)O_(6)was further studied by thermal kinetics,indicating that this process is controlled first by a fibril-like mechanism and then by a spherulitic-type mechanism with an increasing heating ***,the enthalpy change of MgV_(2)O_(6)at high temperatures was measured utilizing the drop calorimetry,heat capacity was calculated and given as:Cp=208.3+0.03583T-4809000T^(−2)(298-923 K)(J mol^(−1)K^(−1)),the high-temperature heat capacity can be used to calculate Gibbs free energy of MgV_(2)O_(6)at high temperatures.

关键词： MgV_(2)O_(6) Crystal structure Phase transitions Thermodynamic functions

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Enhancing corn stalk-based anaerobic digestion with different types of zero-valent iron added during the acidification stage:Performance and mechanism

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Journal of Environmental Sciences 2024年第11期145卷 64-74页

作者： xiang Liu Yue Liu Min Wang Qianzhen Deng Hao Yang College of Agricultural Science and Engineering Hohai UniversityNanjing 210098China State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution Wenzhou UniversityWenzhou 325035China Anhui Provincial Key Laboratory of Environmental Pollution Control and Resource Reuse Anhui Jianzhu UniversityHefei 230009China

Anaerobic digestion has been defined as a competitive approach to facilitate the recycling of corn ***,few studies have focused on the role of direct interspecies electron transfer(DIET)pathway in the acidification stage under the addition of different particle sizes of zero-valent iron(ZVI).In this study,three types of ZVI,namely iron filings,iron powder and nanoscale iron,were investigated,respectively,to enhance its high-value *** in volatile fatty acids(VFAs)and methane(CH4)production associated with the underlyingmechanisms were emphatically *** indicated that the addition of ZVI could increase the concentration of VFAs,with the most outstanding performance observed with the use of nanoscale ***,the conversion of propionic acid to acetic acid was driven by adding ZVI with no between-group differences in acidizing ***,the substrate was more fully utilized when supplied with iron powder compared with other groups in methanogenic phase,thereby displaying the maximumCH4 yield with a value of 263.1 mL/(g total solids(TS)).However,adding nanoscale iron could signally shorten the digestion time(T80),saving 7 days in comparison to the group of iron powder.

关键词： Zero-valent iron Corn stalk Anaerobic digestion Volatile fatty acids Methane

Electronic structural engineering of bimetallic Bi-Cu alloying nanosheet for highly-efficient CO_(2) electroreduction and Zn-CO_(2) batteries

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Nano Research 2024年第5期17卷 3684-3692页

作者： Wenbo Wu Jiaye Zhu Yun Tong Shuangfei xiang Pengzuo Chen School of Chemistry and Chemical Engineering Key Laboratory of Surface and Interface Science of Polymer Materials of Zhejiang ProvinceZhejiang Sci-Tech UniversityHangzhou 310018China

Regulating the electronic structure of Bi-based materials by alloying engineering is promising to promote the electrocatalytic activity,but it remains some challenges to be *** this study,a facile electrochemical co-deposition strategy is developed to synthesize the bimetallic Bi_(9)Cu_(1) alloy nanosheet on carbon cloth(Bi_(9)Cu_(1)/CC),which represents a novel self-supporting electrode for the electrocatalytic carbon dioxide(CO_(2))reduction reaction(CO_(2)RR).The Bi_(9)Cu_(1)/CC catalyst has achieved a remarkable catalytic performance with high Faradaic efficiencies(FE)of over 90%for formate at wide potentials from-0.7 to-1.2 V *** hydrogen electrode(RHE).Moreover,the reversible Zn-CO_(2) battery can be driven by Bi_(9)Cu_(1)/CC cathode with a largest power density of 1.4 mW·cm^(-2),and superior operating *** systematic characterizations and electrochemical results confirm that the improved catalytic active sites,the enhanced mass/charge transport and the optimal reaction kinetics of Bi nanosheet are realized for CO_(2)RR by Cu *** situ attenuated total reflection infrared(ATR-IR)result confirms the bimetallic Bi-Cu active sites prefer to follow the^(*)OCHO conversion *** density functional theory(DFT)calculations suggest that the Cu alloying contributes to the increased density of states near the Fermi surface of Bi and the optimized adsorption of^(*)OCHO intermediates on the Bi sites,resulting in the excellent catalytic performance.

关键词： electronic regulation bismuth nanosheet copper alloying CO_(2)electroreduction Zn-CO_(2)batteries