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Differences in Variations of Long-Lived and Short-Lived Summer Heat Waves during 1981-2020 over Eastern China and Their Corresponding Large-Scale Circulation Anomalies

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Journal of Meteorological Research 2024年第3期38卷 414-436页

作者： Liqun ji Haishan chen Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Key Laboratory of Meteorological Disaster Ministry of EducationNanjing University of Information Science&TechnologyNanjing210044China School of Atmospheric Sciences Nanjing University of Information Science&TechnologyNanjing210044China

Using daily maximum temperature(Tmax)data from 516 observation stations in eastern China from 1981 to 2020,this study employed a relative threshold method to define short-and long-lived heat waves(HWs)by considering regional climate differences to investigate the spatial characteristics and evolution of large-scale circulation during summer *** results demonstrated spatial disparities in the frequency distribution of HWs of different durations and differences in the magnitude of duration and intensity between short-and long-lived *** orthogonal function analysis revealed three dominant spatial modes for both short-and long-lived *** first mode showed that short-lived HWs occur prominently in both northern and southern regions,whereas long-lived HWs mainly occur in the northern *** second mode was characterized by a meridional dipole pattern in both *** third mode exhibited a quadrupole pattern for short-lived HWs and a tripole pattern for long-lived *** in the center locations of anomalies in the 500-hPa geopotential height and 850-hPa wind fields significantly influenced the temperature and precipitation anomaly distribution of typical HWs by affecting the warm column in the lower troposphere,cloud distribution,and moisture ***,the atmospheric circulation evolution processes of typical HWs associated with the different modes of long-and short-lived HWs were linked to distinct teleconnection *** the three modes of long-lived(short-lived)HWs,there was stronger(weaker)wave flux activity with multiple(single)propagation *** westward Atlantic wave train activity at 300 hPa triggered the synergistic action of meridional and zonal wave fluxes,favoring the strengthening and maintenance of positive anomalies in geopotential height of 500 *** may have contributed to the formation of long-lived *** findings provide valuable insights to enhance our understanding and prediction of summer

关键词： short-lived heat waves(HWs) long-lived HWs empirical orthogonal function(EOF)modes large-scale atmospheric circulation

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Influence of Film Thickness on Nanofabrication of Graphene Oxide

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Nanomanufacturing and Metrology 2024年第2期7卷 13-25页

作者： chuan Tang Lei chen Linmao Qian Tribology Research Institute The State Key Laboratory of Rail Vehicle SystemSchool of Mechanical EngineeringSouthwest Jiaotong UniversityChengdu 610031China

Nanofabrication of two-dimensional materials through mechanical machining is normally influenced by not only process parameters such as load and velocity but also intrinsic properties such as strength and ***,we examined the effects of graphene oxide(GO)film thickness on nanofabrication on the plane surfaces and at the step edges using scanning probe microscope *** material removal of GO initiates at the load above a critical value,which strongly depends on film thickness and *** the increase in film thickness,the critical load decreases monotonically on the plane surfaces but increases gradually at the step ***,the critical load for the GO monolayer at the step edges is at least 25 times lower than that on the plane surfaces,and the gap decreases to around 3 times when GO thickness increases to four ***,mechanical nanofabrication initiating from the GO step edge allows producing various nanopatterns under extremely low loads around 1 ***,the GO nanostructures are deoxidized by annealing at 800°C in high-purity argon to restore their highly functionalized conjugated structures,which are supported by X-ray diffraction and Raman *** work provides a novel approach to fabricating graphene-like nanostructures by deoxidizing GO after nanofabrication,which holds significant potential for applications in graphene-based devices.

关键词： Graphene oxide Nanofabrication Film thickness step edge Nanopattern Deoxidized treatment

In-situ powder mixing for laser-based directed energy deposition of functionally graded materials

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Advances in Manufacturing 2024年第1期12卷 150-166页

作者： ji-Peng chen Shou-Chun Xie He Huang School of Mechanical and Electronic Engineering Nanjing Forestry UniversityNanjing210037People’s Republic of China Nanjing Huirui Photoelectric Technology Co. LtdNanjing211121People’s Republic of China

The mixing of powders is a highly relevant field under additive manufacturing,however,it has attracted limited interest to *** in-situ mixing of various powders remains a significant *** paper proposes a new method utilizing a static mixer for the in-situ mixing of multiple powders through the laser-based directed energy deposition(DED)of functionally graded ***,a powder-mixing experimental platform was established;WC and 316L powders were selected for the mixing ***,scanning electron microscopy,energy dispersive spectroscopy,and image processing were used to visually evaluate the homogeneity and proportion of the in-situ mixed ***,powder-mixing simulations were conducted to determine the powder-mixing *** the simulations,a powder carrier gas flow field and particle mixing were ***,a WC/316L metal matrix composite sample was produced using laser-based DED to verify the application potential of the static *** was found that the static mixer could adjust the powder ratio online,and a response time of 1–2 s should be considered when adjusting the ratio of the mixed powder.A feasible approach for in-situ powder mixing for laser-based DED was demonstrated and investigated,creating the basis for functionally graded materials.

关键词： Laser Deposition Static mixer Powder mixing Functionally graded materials

A Dual Closed-Loop Digital Twin Construction Method for Optimizing the Copper Disc Casting Process

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IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 581-594页

作者： Zhaohui jiang chuan Xu jinshi Liu Weichao Luo Zhiwen chen Weihua Gui IEEE the School of Automation Central South UniversityChangsha 410083China the Peng cheng Laboratory Shenzhen 518000China

The copper disc casting machine is core equipment for producing copper anode plates in the copper metallurgy *** copper disc casting machine casting package motion curve(CPMC) is significant for precise casting and efficient ***,the lack of exact casting modeling and real-time simulation information severely restricts dynamic CPMC *** this end,a liquid copper droplet model describes the casting package copper flow pattern in the casting ***,a CPMC optimization model is proposed for the first *** top of this,a digital twin dual closed-loop self-optimization application framework(DT-DCS) is constructed for optimizing the copper disc casting process to achieve self-optimization of the CPMC and closed-loop feedback of manufacturing information during the casting ***,a case study is carried out based on the proposed methods in the industrial field.

关键词： Copper disc casting machine digital twin(DT) mechanism modeling self-optimization

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Polyoxometalates for continuous power generation by atmospheric humidity

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Nano Research 2024年第3期17卷 1875-1885页

作者： Tuo ji Weilin chen Zhenhui Kang Liming Zhang Key Laboratory of Polyoxometalate and Reticular Material Chemistry of Ministry of Education Northeast Normal UniversityChangchun 130024China Institute of Functional Nano&Soft Materials(FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials&Devices DepartmentSoochow UniversitySuzhou 215123China Macao Institute of Materials Science and Engineering Macao University of Science and TechnologyTaipaMacao 999078China Institute of Functional State Key Laboratory of Luminescence and Applications Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China

Atmospheric humidity is a sustainable low-value energy widely existing in natural environment,which is a promising candidate to solve the noncontinuous and low efficiency of low-value energy power *** the mono-substituted Dawson-type polyoxometalates are constructed to be highly dispersed organic ammonium-polyoxoanion clusters and are assembled into thin films power generators with micropores,working in atmospheric *** optimal polyoxometalates generator with the thickness of 7.2μm and the area of 0.36 cm^(2) produces a voltage of 0.68 V and a current density of 19.5μA·cm^(-2) under simulated natural environment,and works continuously and stably under almost all-natural environments(humidity 10%–90%).The highly dispersed polyoxometalate nanoclusters can form microporous in polyoxometalate films to effectively absorb atmospheric humidity and spontaneously form distribution gradient of water,which is the structural basis of power *** continuous power generation may be maintained by the effective adsorption and utilization of H_(2)O,the huge electrostatic field of organic ammonium-polyoxoanion clusters,and the reasonably designed polyoxometalates containing inorganic small ions with high *** is the first humidity generator designed with polyoxometalates,which may provide a new research direction for polyoxometalates in sustainable utilization of low-value energy.

关键词： atmospheric humidity continuous power generations nanomaterials polyoxoanions polyoxometalates

Transitional Revenue Scheme for High-cost Generator Unit in Guangdong Electricity Market Based on Government Authorized Contracts

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 208-221页

作者： jisong Zhu Baike chen Tianyao ji Zhaoxia jing School of Electric Power Engineering South China University of TechnologyGuangzhou 510640China

High-cost generator units are at a cost disadvantage in electricity spot *** study focuses on revenue mechanisms of gas-fired units affected by power market reform in Guangdong province,*** the first time,we compare impacts on market indicators of five settlement mechanisms:feed-in tariff(FiT),location marginal price(LMP),contract for difference(CFD),direct subsidy(DS),and estimated revenue method(ERM).In particular,we design key parameters,including authorized CFD and ERM of two kinds of government authorized contracts based on traditional dispatching patterns to avoid significant profit fluctuations brought by market *** also analyze impact of factors such as climbing performance,seasonal load,and subsidy amount on the overall market and its *** of a case study show to directly subsidize gasfired units will lead higher-cost units to generate more electricity,with a resulting loss of social *** of market prices and provision of unreasonable incentives are fatal disadvantages of this subsidy *** government and policymakers should consider financial means to adjust benefits to reduce production costs and increase social ***,by case analysis,the ERM shows its stable performance in revenue of high-cost units,while we find that authorized CFD is not applicable for gas-fired units whose output is unstable as a marginal unit ***,we suggest government agencies adopt ERM to sign contracts with gas-fired units,to attain a balance between fairness and efficiency.

关键词： Guangdong electricity market high-cost generator unit settlement mechanism subsidy

Coupled DEM-FDM analyses of the effects of falling rock’s shape and impact angle on response of granular cushion and rock shed

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 3353-3364页

作者： jingyu Xue chen Cao jianhua Yan Yaopeng ji jianping chen College of Construction Engineering Jilin UniversityChangchun130026China School of Earth Sciences and Engineering Hohai UniversityNanjing210098China

Rock shed is an effective protection measure against *** investigate the influences of falling rock’s shape and impact angle on the impact effect of the cushioned rock shed,a modeling approach for a rock shed with a cushion layer using *** granular cushion is modeled as an aggregate of discrete non-cohesion particles,while the concrete plate and the beam are modeled as *** falling rock with different sphericities and impact angles is modeled as a rigid *** numerical model is validated by comparing the simulation results with experimental and numerical results from previous *** model is applied to analyze the effects of rock shape and impact angle on the dynamic interaction effects between falling rock and cushioned rock shed,including the impact force,transmitted bottom force,penetration depth,and plate *** numerical results show that the variation in the falling rock’s shape has different effects on the falling rock with different impact *** findings could support rock shed design by revealing the limitations of the assumptions in the past research,which may result in unsafe rock sheds for some rockfall cases.

关键词： Rockfall Coupled DEM-FDM analysis Rock’s shape Impact angle Granular cushion Rock shed

Axial enantiomers with donor-regulated TADF feature for multicolor circularly polarized electroluminescence

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Science China Chemistry 2024年第6期67卷 2039-2045页

作者： chen-Hao Guo Wen-Long Zhao Ke-Ke Tan Wei-chen Guo Liheng Feng chuan-Feng chen Meng Li School of Chemistry and Chemical Engineering Shanxi UniversityTaiyuan030006China Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Molecular Recognition and FunctionInstitute of ChemistryChinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100049China

This study optimized the TADF feature of axial chiral enantiomers through precise donor engineering,and multicolor CP-TADFwas achieved in the axial chiral *** pairs of axial enantiomers with donor-regulated TADF feature,namely(R/S)-TPCBD,(R/S)-DPCBD,and(R/S)-DPACBD,were synthesized by introducing carbazole donors with different substituents onto biphenyl cyanide *** the electron-donating ability of donors increases,the emission of these axial enantiomers ranges from 455,476 to 552 nm,their singlet-triplet energy gaps(ΔE_(ST))gradually decrease from 0.30,0.22 to 0.02 e V,accompanied by an increasement in the transition rate(k_(RISC))of RISC process,and the k_(RISC)of DPACBD could reach up to 7.16×10^(5)s^(-1).These axial enantiomers also exhibit mirror-image CD and circularly polarized luminescence(CPL)***,OLEDs based on TPCBD,DPCBD,and DPACBD as emitter were then fabricated,which displayed blue,green,and orange electroluminescence with EQE_(max)of 13.0%,16.4%,and 25.0%,*** results also exhibited a phenomenon of device efficiency increasing with the enhancement of donor ***,the CP-OLEDs using(R/S)-TPCBD,(R/S)-DPCBD and(R/S)-DPACBD as emitters displayed intense CPEL signals with g_(EL)values of 3.4×10^(-3)/-4.1×10^(-3),3.2×10^(-3)/-3.1×10^(-3)and2.3×10^(-3)/-2.1×10^(-3),*** convenient molecular engineering of donor regulation in the same molecular skeleton,CP-TADF materials with multicolor CPEL and improved device performance could be conveniently achieved.

关键词： axial chirality thermally activated delayed fluorescence circularly polarized luminescence electroluminescence organic light-emitting diodes

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Breakthrough architecture conquers dark current:echoes of Dujiangyan in perovskite photodetectors

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Advanced Photonics 2024年第3期6卷 5-6页

作者： Yujin Liu Zhong ji Xueli chen Xidian University Guangzhou Institute of Technology Innovation Center for Advanced Medical Imaging and Intelligent Medicine Xidian University School of Life Science and Technology Center for Biomedical-photonics and Molecular ImagingXi'an Key Laboratory of Intelligent Sensing and Regulation of Trans-Scale Life Information

Metal halide perovskites（MHPs） photodetectors（PDs） exhibiting outstanding and tunable photoelectric properties have attracted extensive global attention owing to their low-temperature solution-processable fabrication, lightweight nature, and flexibility.1However, MHPs-based PDs still face challenges of high and unstable dark current, which limit their operational stability and practical applications.2

关键词： Dark current Perovskite Palladium Ions Electrodes Photodetectors Control systems Electric fields Photocurrent Signal detection