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A benchmark-based method for evaluating hyperparameter optimization techniques of neural networks for surface water quality prediction

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Frontiers of Environmental Science & Engineering 2024年第5期18卷 13-27页

作者： xuan Wang yan Dong Jing yang Zhipeng liu Jinsuo Lu School of Environmental and Municipal Engineering Xi’an University of Architecture and TechnologyXi’an710055China Shaanxi Key Laboratory of Environmental Engineering Xi’an University of Architecture and TechnologyXi’an710055China State Key Laboratory of Green Building in West China Xi’an University of Architecture and TechnologyXi’an710055China

Neural networks(NNs)have been used extensively in surface water prediction tasks due to computing algorithm improvements and data *** essential step in developing an NN is the hyperparameter *** practice,it is common to manually determine hyperparameters in the studies of NNs in water resources *** may result in considerable randomness and require significant computation time;therefore,hyperparameter optimization(HPO)is *** study adopted five representatives of the HPO techniques in the surface water quality prediction tasks,including the grid sampling(GS),random search(RS),genetic algorithm(GA),Bayesian optimization(BO)based on the Gaussian process(GP),and the tree Parzen estimator(TPE).For the evaluation of these techniques,this study proposed a method:first,the optimal hyperparameter value sets achieved by GS were regarded as the benchmark;then,the other HPO techniques were evaluated and compared with the benchmark in convergence,optimization orientation,and consistency of the optimized *** results indicated that the TPE-based BO algorithm was recommended because it yielded stable convergence,reasonable optimization orientation,and the highest consistency rates with the benchmark *** optimization consistency rates via TPE for the hyperparameters hidden layers,hidden dimension,learning rate,and batch size were 86.7%,73.3%,73.3%,and 80.0%,*** the evaluation of HPO techniques directly based on the prediction performance of the optimized NN in a single HPO test,the proposed benchmark-based HPO evaluation approach is feasible and robust.

关键词： Neural networks Hyperparameter optimization Surface water quality prediction Bayes optimization Genetic algorithm

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Understanding the Activity Performance of Comets 38P/Stephan-Oterma,64P/Swift-Gehrels and C/2017 M4(ATLAS) through Broadband Photometric Observations

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Research in Astronomy and Astrophysics 2024年第8期24卷 149-158页

作者： xuan Zhang Jin-Zhong liu Le-Tian Wang Xinjiang Astronomical Observatory Chinese Academy of Sciences

In this work,we report observations of three comets:38P/Stephan-Oterma,64P/Swift-Gehrels,and C/2017 M4（ATLAS）,conducted with the Nanshan one-meter wide-field telescope in 2018 August and November,and *** extracted morphological features through image enhancement techniques and calculated the dust activity parameter,Afρ,along with dust mass loss rates and coma color indices using broadband photometric *** morphological analysis uncovered a spectrum of dust characteristics among the observed comets,ranging from a significant twisted structure in comet 38P/Stephan-Oterma’s coma to the regular coma envelope surrounding comet 64P/*** Afρvalues varied between 148.8±0.3 cm for 64P/Swift-Gehrels and1118.5±6.2 cm for C/2017 M4 （ATLAS）(measured within a reference aperture radius ofρ=6″),indicating a range from moderate to high activity *** mass loss rates were estimated from 328.1 kg s-1for comet 64P/Swift-Gehrels to 1395.5 kg s-1for comet C/2017 M4 （ATLAS）.The color indices of comets 38P/Stephan-Oterma and C/2017 M4 （ATLAS） closely resemble the average colors of active short-period comets and active longperiod comets,*** contrast,64P/Swift-Gehrels exhibits a significantly bluer hue than typical Jupiter family comets.

关键词： comets: general comets: individual (38P/Stephan-Oterma, 64P/Swift-Gehrels, C/2017 M4 (ATLAS)) techniques: photometric

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Enantioselective Synthesis of Benzimidazole Atropisomers Featuring a N-N Axis

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Chinese Journal of Chemistry 2024年第7期42卷 711-718页

作者： Fang-Bei Ge Qi-Kun yin Chuan-Jun Lu xuan xuan Jia Feng Ren-Rong liu College of Chemistry and Chemical Engineering Qingdao UniversityQingdaoShandong 266071China School of Pharmacy Key Laboratory of Molecular Pharmacology and Drug EvaluationMinistry of EducationYantai UniversityYantaiShandong 264005China

Atroposelective synthesis of N-N atropisomers is an emerging area but remains underexplored;in particular,the synthesis of N-N benzimidazole atropisomers is still ***,the first enantioselective synthesis of N-N benzimidazole atropisomers via the palladium-catalyzed de novo construction of benzimidazole skeleton is *** readily available palladium catalyst and biphosphine ligand,a broad range of nonbiaryl benzimidazole and indole-benzimidazole atropisomers were conveniently ac-cessed in high yields and with excellent ***,these N-N benzimidazole atropisomers showed great anti-tumor activity and selectivity to breast cancer MCF-7 *** simple catalytic system,broad substrate scope,high enantioselectivi-ty,and good bioactivity make this approach highly attractive.

关键词： Asymmetric synthesis Atropisomerism Palladium Benzimidazole Antitumor

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Intelligent Reflecting Surface Assisted Transmission Optimization Strategies in Wireless Networks

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China Communications 2024年第4期21卷 120-135页

作者： He Xinxin Qi xuan Meng Wei liu Wei yin Changchuan School of Electronic Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China

Wireless Power Transfer(WPT)technology can provide real-time power for many terminal devices in Internet of Things(IoT)through millimeterWave(mmWave)to support applications with large capacity and low *** the intelligent reflecting surface(IRS)can be adopted to create effective virtual links to address the mmWave blockage problem,the conventional solutions only adopt IRS in the downlink from the Base Station(BS)to the users to enhance the received signal *** practice,the reflection of IRS is also applicable to the uplink to improve the spectral *** is a challenging to jointly optimize IRS beamforming and system resource allocation for wireless energy acquisition and information *** this paper,we first design a Low-Energy Adaptive Clustering Hierarchy(LEACH)clustering protocol for clustering and data ***,the problem of maximizing the minimum system spectral efficiency is constructed by jointly optimizing the transmit power of sensor devices,the uplink and downlink transmission times,the active beamforming at the BS,and the IRS dynamic *** solve this non-convex optimization problem,we propose an alternating optimization(AO)-based joint solution *** results show that the use of IRS dynamic beamforming can significantly improve the spectral efficiency of the system,and ensure the reliability of equipment communication and the sustainability of energy supply under NLOS link.

关键词： intelligent reflecting surface(IRS) joint optimization millimeter wave wireless information transmission(WIT) wireless power transfer(WPT)

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Climate change,ambient air pollution,and students'mental health

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World Journal of Psychiatry 2024年第2期14卷 204-209页

作者： Jing-xuan Wang Xin-Qiao liu School of Education Tianjin UniversityTianjin 300350China

The impact of global climate change and air pollution on mental health has become a crucial public health *** public awareness of health,advancements in medical diagnosis and treatment,the way media outlets report environmental changes and the variation in social resources affect psychological responses and adaptation methods to climate change and air *** the context of climate change,extreme weather events seriously disrupt people's living environments,and unstable educational environments lead to an increase in mental health issues for *** pollution affects students'mental health by increasing the incidence of diseases while decreasing contact with nature,leading to problems such as anxiety,depression,and decreased cognitive *** call for joint efforts to reduce pollutant emissions at the source,improve energy structures,strengthen environmental monitoring and governance,increase attention to the mental health issues of students,and help student groups build resilience;by establishing public policies,enhancing social support and adjusting lifestyles and habits,we can help students cope with the constantly changing environment and maintain a good level of mental *** these comprehensive measures,we can more effectively address the challenges of global climate change and air pollution and promote the achievement of the United Nations Sustainable Development Goals.

关键词： Climate change Ambient air pollution Mental health Energy structure Public policy Sustainable development

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Effects of dimethyl ether and ethanol additions on soot transition in ethylene counterflow diffusion flames

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Science China(Technological Sciences) 2024年第4期67卷 1094-1112页

作者： GUO LinGe yING yaoyao CHEN Chen ZHAO xuan liu Dong MIIT Key Laboratory of Thermal Control of Electronic Equipment School of Energy and Power EngineeringNanjing University of Science and TechnologyNanjing 210094China Advanced Combustion Laboratory School of Energy and Power EngineeringNanjing University of Science and TechnologyNanjing 210094China

This paper investigates the effect of blending dimethyl ether(DME)and ethanol on the soot transition periods in ethylene counterflow diffusion flames by using a novel optical diagnostic *** soot critical transition point in different conditions is identified experimentally and *** kinds of flames are carried out to gain the soot critical transition point in counterflow diffusion flames by changing oxygen fraction(Xo)and changing volume flow rates of fuel and oxidizer(Qv).The red-green-blue(RGB)ratio method is used to precisely identify the soot critical transition point,and chemical kinetic simulations are performed to analyze the detailed reaction *** results show that compared to the ethylene flame,the soot critical transition point occurs at a higher Xoand a lower Qvwhen DME or ethanol is *** addition of DME and ethanol can inhibit soot formation,due to the degree of soot formation reaction being lower than the degree of the oxidation reaction in the blending flames.

关键词： optical diagnosis sooting tendency counterflow diffusion flame dimethyl ether ethanol

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Evolution of mechanical properties,localized corrosion resistance and microstructure of a high purity Al-Zn-Mg-Cu alloy during non-isothermal aging

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Journal of Central South University 2024年第6期31卷 1790-1807页

作者： DAI xuan-xuan LI yu-zhang liu Sheng-dan yE Ling-ying BAO Chong-jun School of Materials Science and Engineering Central South UniversityChangsha 410083China Key Laboratory of Lightweight and High-strength Structural Materials Changsha 410083China Key Laboratory of Non-ferrous Metals Science and Engineering(Ministry of Education) Changsha 410083China Kunming Metallurgical Research Institute Co. Ltd.Kunming 650031China

The evolution of mechanical properties,localized corrosion resistance of a high purity Al-Zn-Mg-Cu alloy during non-isothermal aging(NIA)was investigated by hardness test,electrical conductivity test,tensile test,intergranular corrosion test,exfoliation corrosion test,slow strain rate tensile test and electrochemical test,and the mechanism has been discussed based on microstructure examination by optical microscopy,electron back scattered diffraction,scanning electron microscopy and scanning transmission electron *** NIA treatment includes a heating stage from 40℃to 180℃with a rate of 20℃/h and a cooling stage from 180℃to 40℃with a rate of 10℃/*** results show that the hardness and strength increase rapidly during the heating stage of NIA since the increasing temperature favors the nucleation and the growth of strengthening precipitates and promotes the transformation of Guinier-Preston(GPI)zones toη'*** the cooling stage,the sizes ofη'phase increase with a little change in the number density,leading to a further slight increase of the hardness and *** NIA proceeds,the corroded morphology in the alloy changes from a layering feature to a wavy feature,the maximum corrosion depth decreases,and the reason has been analyzed based on the microstructural and microchemical feature of precipitates at grain boundaries and subgrain boundaries.

关键词： Al-Zn-Mg-Cu alloy non-isothermal aging mechanical properties localized corrosion resistance microstructure

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A STAMP-Game model for accident analysis in oil and gas industry

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Petroleum Science 2024年第3期21卷 2154-2167页

作者： Huixing Meng Xu An Daiwei Li Shijun Zhao Enrico Zio xuan liu Jinduo Xing State Key Laboratory of Explosion Science and Safety Protection Beijing Institute of TechnologyBeijing100081China School of Emergency Management and Safety Engineering China University of Mining and Technology(Beijing)Beijing100083China Energy Department Politecnico di MilanoVia La Masa 34Milan20156Italy Mines Paris PSL Centre de Recherche sur les Risques et les CrisesSophie Antipolis06904France School of Mechanical-Electronic and Vehicle Engineering Beijing University of Civil Engineering and ArchitectureBeijing100044China

Accidents in engineered systems are usually generated by complex socio-technical *** is beneficial to investigate the increasing complexity and coupling of these factors from the perspective of system *** on system and control theories,System-Theoretic Accident Model and Processes(STAMP)is a widely recognized approach for accident *** this paper,we propose a STAMP-Game model to analyze accidents in oil and gas storage and transportation *** in accident analysis by STAMP can be regarded as players of a *** theory can,thus,be adopted in accident analysis to depict the competition and cooperation between ***,we established a game model to study the strategies of both supervisory and supervised *** obtained results demonstrate that the proposed game model allows for identifying the effectiveness deficiency of the supervisory entity,and the safety and protection altitudes of the supervised *** STAMP-Game model can generate quantitative parameters for supporting the behavior and strategy selections of the supervisory and supervised *** quantitative data obtained can be used to guide the safety improvement,to reduce the costs of safety regulation violation and accident risk.

关键词： Accident analysis STAMP System engineering Gametheory Oil and gas storage and transportation systems

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Atmospheric iron deposition in a megacity of northwest China:Solubility,speciation,and deposition fluxes

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Particuology 2024年第7期90卷 383-393页

作者： Xiaotao yang Pingping liu Zhiwei Xue Hao Zhang xuan Li Hongmei Xu Zhenxing Shen Department of Environmental Science and Engineering Xi'an Jiaotong UniversityXi'anChina State Key Laboratory of Loess and Quaternary National Key R&D of China Geology Institute of Earth EnvironmentChinese Academy of SciencesXi'anChina No.203 Research Institute of Nuclear Industry Xi'an710086China Xi'an Environmental Monitoring Station Xi'an 710054China

Atmospheric iron has crucial effects on biogeochemical cycles,atmospheric processing,global climate,and human *** this study,atmospheric dustfall samples were collected from six functional areas in Xi'an,China,from 2020 to *** spatiotemporal distributions and deposition fluxes of total and water-soluble(ws)Fe as well as the speciation and potential sources of ws-Fe were *** areas had the highest concentrations of total Fe and ws-Fe,which were mainly due to copious emissions of heavy metals during *** total Fe concentrations peaked in spring,primarily due to the substantial input of crustal dust,which also led to the lowest Fe solubility in this *** contrast,the highest levels of ws-Fe occurred during winter due to an increase in biomass *** the water-soluble forms,ws-Fe(II)was dominant and accounted for 74.8%of the total amount of *** dust was the main contributor to total Fe,whereas biomass burning primarily contributed to peak ws-Fe *** average total and ws-Fe deposition fluxes in Xi'an were the highest in spring and lowest in autumn,which were related to the distributions of the dustfall deposition fluxes and their Fe contents during these *** study provided a broader and comprehensive understanding of atmospheric iron deposition in Chinese urban area,which is of positive significance for understanding atmospheric chemistry and global climate change.

关键词： Atmospheric dustfall Iron Speciation distribution Seasonal variation Functional area Sources

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Dynamic interactive bitwise meta-holography with ultra-high computational and display frame rates

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Opto-Electronic Advances 2024年第1期7卷 36-46页

作者： yuncheng liu Ke Xu Xuhao Fan Xinger Wang xuan yu Wei Xiong Hui Gao Wuhan National Laboratory for Optoelectronics and School of Optical and Electronic Information Huazhong University of Science and TechnologyWuhan 430074China Optics Valley Laboratory Wuhan 430074China

Interactive holography offers unmatched levels of immersion and user engagement in the field of future *** of the substantial progress has been made in dynamic meta-holography,the realization of real-time,highly smooth interactive holography remains a significant challenge due to the computational and display frame rate *** this study,we introduced a dynamic interactive bitwise meta-holography with ultra-high computational and display frame *** our knowledge,this is the first reported practical dynamic interactive metasurface holographic *** spa-tially divided the metasurface device into multiple distinct channels,each projecting a reconstructed *** switching states of these channels were mapped to bitwise operations on a set of bit values,which avoids complex holo-gram computations,enabling an ultra-high computational frame *** approach achieves a computational frame rate of 800 kHz and a display frame rate of 23 kHz on a low-power Raspberry Pi computational *** to this methodology,we demonstrated an interactive dynamic holographic Tetris game system that allows interactive gameplay,color display,and on-the-fly hologram *** technology presents an inspiration for advanced dynamic meta-holography,which is promising for a broad range of applications including advanced human-computer interaction,real-time 3D visualization,and next-generation virtual and augmented reality systems.

关键词： interactive display meta-holography bitwise operation ultra-high frame rate

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