期刊文献+
共找到176,380篇文章
< 1 2 250 >
每页显示 20 50 100
Two-dimensional nanomaterials for environmental catalysis roadmap towards 2030
1
作者 Jing Guo Jianzhong Ma +18 位作者 Junli Liu Guanjie Huang Xiaoting Zhou Francesco Parrino Riccardo Ceccato Leonardo Palmisano Boon-Junn Ng Lutfi Kurnianditia Putri Huaxing Li Rongjie Li Gang Liu Yang Wang Nikolay Kornienko Shan-Shan Zhu Zhenwei Zhang Xiaoming Liu Nur Atika Nikma Dahlan Siang-Piao Chai Jianmin Ma 《Chinese Chemical Letters》 2025年第9期223-235,共13页
Environmental catalysis has been considered one of the important research topics.Some technologies(e.g.,photocatalysis and electrocatalysis)have been intensively developed with the advance of synthetic technologies of... Environmental catalysis has been considered one of the important research topics.Some technologies(e.g.,photocatalysis and electrocatalysis)have been intensively developed with the advance of synthetic technologies of catalytical materials.In 2019,we discussed the development trend of this field,and wrote a roadmap on this topic in Chinese Chemical Letters(30(2019)2065-2088).Nowadays,we discuss it again from a new viewpoint along this road.In this paper,several subtopics are discussed,e.g.,photocatalysis based on titanium dioxide,violet phosphorus,graphitic carbon and covalent organic frameworks,electrocatalysts based on carbon,metal-and covalent-organic framework.Finally,we hope that this roadmap can enrich the development of two-dimensional materials in environmental catalysis with novel understanding,and give useful inspiration to explore new catalysts for practical applications. 展开更多
关键词 environmental catalysis two-dimensional materials ELECTROCATALYSIS PHOTOCATALYSIS NANOMATERIALS
原文传递
Two-Dimensional MXene-Based Advanced Sensors for Neuromorphic Computing Intelligent Application
2
作者 Lin Lu Bo Sun +2 位作者 Zheng Wang Jialin Meng Tianyu Wang 《Nano-Micro Letters》 2026年第2期664-691,共28页
As emerging two-dimensional(2D)materials,carbides and nitrides(MXenes)could be solid solutions or organized structures made up of multi-atomic layers.With remarkable and adjustable electrical,optical,mechanical,and el... As emerging two-dimensional(2D)materials,carbides and nitrides(MXenes)could be solid solutions or organized structures made up of multi-atomic layers.With remarkable and adjustable electrical,optical,mechanical,and electrochemical characteristics,MXenes have shown great potential in brain-inspired neuromorphic computing electronics,including neuromorphic gas sensors,pressure sensors and photodetectors.This paper provides a forward-looking review of the research progress regarding MXenes in the neuromorphic sensing domain and discussed the critical challenges that need to be resolved.Key bottlenecks such as insufficient long-term stability under environmental exposure,high costs,scalability limitations in large-scale production,and mechanical mismatch in wearable integration hinder their practical deployment.Furthermore,unresolved issues like interfacial compatibility in heterostructures and energy inefficiency in neu-romorphic signal conversion demand urgent attention.The review offers insights into future research directions enhance the fundamental understanding of MXene properties and promote further integration into neuromorphic computing applications through the convergence with various emerging technologies. 展开更多
关键词 two-dimensional MXenes SENSOR Neuromorphic computing Multimodal intelligent system Wearable electronics
在线阅读 下载PDF
Two-dimensional conjugated metal-organic framework nanosheets:Synthesis and applications
3
作者 Jin Yan Yong Li +10 位作者 Ziming Qiu Zhenyang Meng Shengnan Zhou Limei Liu Chengze Li Hao Lin Qixin Mao Xiang Yu Yu Fan Yecan Pi Huan Pang 《Nano Research》 2026年第1期50-74,共25页
Two-dimensional conjugated metal-organic framework(2D c-MOF)nanosheets have garnered significant research interest owing to their suite of distinctive properties.Consequently,diverse synthetic methodologies have been ... Two-dimensional conjugated metal-organic framework(2D c-MOF)nanosheets have garnered significant research interest owing to their suite of distinctive properties.Consequently,diverse synthetic methodologies have been established for the fabrication of 2D c-MOFs exhibiting welldefined nanosheet morphology.In addition,the structural engineering of 2D c-MOF nanosheets for energy storage and conversion has emerged as a prominent research focus.This review comprehensively summarizes recent advancements in 2D c-MOF nanosheets.We commence with a concise overview of diverse synthesis strategies for these materials.Subsequently,progress in their utilization as electrode materials or catalysts for batteries,supercapacitors,and electrocatalysis/photocatalysis is systematically examined.Finally,prevailing challenges and prospective research directions are discussed.Collectively,this review aims to stimulate the development of sophisticated 2D c-MOF nanosheets for high-performance energy applications. 展开更多
关键词 two-dimensional materials conjugated metal-organic frameworks NANOSHEETS SYNTHESIS energy storage and conversion
原文传递
Physicochemical regulations of nanoconfined two-dimensional spacing toward highly-selective NH_(3) sensing
4
作者 Tianshu Chu Xinyuan Mao +4 位作者 Linfeng Li Tao Wang Xiaoyuan Wang Bowei Zhang Fu-Zhen Xuan 《Nano Research》 2026年第1期1145-1155,共11页
Nanoscale confinement environments often affect the transport mechanisms of nanofluids.Understanding the dynamic behavior of molecules in two-dimensional(2D)confined channels is of great importance in the areas of sen... Nanoscale confinement environments often affect the transport mechanisms of nanofluids.Understanding the dynamic behavior of molecules in two-dimensional(2D)confined channels is of great importance in the areas of sensing,catalysis and energy storage.As a popular candidate for a new type of gas sensing material,MXenes have the problem of nonselectivity towards polar gases with slow responses,which severely limits their applications.Here,we report a study on regulating the confinement effect of 2D channels between MXene layers through annealing treatment and ion(Na^(+))intercalation for high-performance ammonia(NH_(3))sensing.Firstly,the annealing treatment accurately modulates the size of the 2D channels to effectively block the entry of large-size gas molecules and improve the selectivity for NH_(3).Ab initio molecular dynamics(AIMD)also confirms that the modulated channel size has a special"nano-pumping effect",which can accelerate the dynamic behavior of NH_(3) molecules in the 2D confined space.Moreover,the intercalation of Na+ions increases the adsorption capacity of NH_(3).Therefore,the"nano-pumping effect"and theintercalation of Na+ions effectively enhance the response speed and sensitivity of MXene to NH_(3),respectively.The experimental results show that the modified Ti_(3)C_(2) exhibits high sensitivity(0.17),rapid response(181 s),excellent selectivity and stability towards NH_(3). 展开更多
关键词 two-dimensional(2D)materials physicochemical regulation ion intercalation gas sensing nanoconfined space
原文传递
Impact of Data Processing Techniques on AI Models for Attack-Based Imbalanced and Encrypted Traffic within IoT Environments
5
作者 Yeasul Kim Chaeeun Won Hwankuk Kim 《Computers, Materials & Continua》 2026年第1期247-274,共28页
With the increasing emphasis on personal information protection,encryption through security protocols has emerged as a critical requirement in data transmission and reception processes.Nevertheless,IoT ecosystems comp... With the increasing emphasis on personal information protection,encryption through security protocols has emerged as a critical requirement in data transmission and reception processes.Nevertheless,IoT ecosystems comprise heterogeneous networks where outdated systems coexist with the latest devices,spanning a range of devices from non-encrypted ones to fully encrypted ones.Given the limited visibility into payloads in this context,this study investigates AI-based attack detection methods that leverage encrypted traffic metadata,eliminating the need for decryption and minimizing system performance degradation—especially in light of these heterogeneous devices.Using the UNSW-NB15 and CICIoT-2023 dataset,encrypted and unencrypted traffic were categorized according to security protocol,and AI-based intrusion detection experiments were conducted for each traffic type based on metadata.To mitigate the problem of class imbalance,eight different data sampling techniques were applied.The effectiveness of these sampling techniques was then comparatively analyzed using two ensemble models and three Deep Learning(DL)models from various perspectives.The experimental results confirmed that metadata-based attack detection is feasible using only encrypted traffic.In the UNSW-NB15 dataset,the f1-score of encrypted traffic was approximately 0.98,which is 4.3%higher than that of unencrypted traffic(approximately 0.94).In addition,analysis of the encrypted traffic in the CICIoT-2023 dataset using the same method showed a significantly lower f1-score of roughly 0.43,indicating that the quality of the dataset and the preprocessing approach have a substantial impact on detection performance.Furthermore,when data sampling techniques were applied to encrypted traffic,the recall in the UNSWNB15(Encrypted)dataset improved by up to 23.0%,and in the CICIoT-2023(Encrypted)dataset by 20.26%,showing a similar level of improvement.Notably,in CICIoT-2023,f1-score and Receiver Operation Characteristic-Area Under the Curve(ROC-AUC)increased by 59.0%and 55.94%,respectively.These results suggest that data sampling can have a positive effect even in encrypted environments.However,the extent of the improvement may vary depending on data quality,model architecture,and sampling strategy. 展开更多
关键词 Encrypted traffic attack detection data sampling technique AI-based detection IoT environment
在线阅读 下载PDF
Two-dimensional nanomaterials confined single atoms: New opportunities for environmental remediation 被引量:3
6
作者 Yu Yin Lei Shi +4 位作者 Shu Zhang Xiaoguang Duan Jinqiang Zhang Hongqi Sun Shaobin Wang 《Nano Materials Science》 EI CAS CSCD 2023年第1期15-38,共24页
Two-dimensional(2D)supports confined single-atom catalysts(2D SACs)with unique geometric and electronic structures have been attractive candidates in different catalytic applications,such as energy conversion and stor... Two-dimensional(2D)supports confined single-atom catalysts(2D SACs)with unique geometric and electronic structures have been attractive candidates in different catalytic applications,such as energy conversion and storage,value-added chemical synthesis and environmental remediation.However,their environmental appli-cations lack of a comprehensive summary and in-depth discussion.In this review,recent progresses in synthesis routes and advanced characterization techniques for 2D SACs are introduced,and a comprehensive discussion on their applications in environmental remediation is presented.Generally,2D SACs can be effective in catalytic elimination of aqueous and gaseous pollutants via radical or non-radical routes and transformation of toxic pollutants into less poisonous species or highly value-added products,opening a new horizon for the contami-nant treatment.In addition,in-depth reaction mechanisms and potential pathways are systematically discussed,and the relationship between the structure-performance is highlighted.Finally,several critical challenges within this field are presented,and possible directions for further explorations of 2D SACs in environmental remediation are suggested.Although the research of 2D SACs in the environmental application is still in its infancy,this review will provide a timely summary on the emerging field,and would stimulate tremendous interest for designing more attractive 2D SACs and promoting their wide applications. 展开更多
关键词 Single-atom catalysis two-dimensional material Advanced oxidation process Degradation Transformation Industrial wastewater
在线阅读 下载PDF
2020 Roadmap on two-dimensional nanomaterials for environmental catalysis 被引量:2
7
作者 Yulu Yang Mingguang Wu +36 位作者 Xingwang Zhu Hui Xu Si Ma Yongfeng Zhi Hong Xia Xiaoming Liu Jun Pan Jie-Yinn Tang Siang-Piao Chai Leonardo Palmisano Francesco Parrino Junli Liu Jianzhong Ma Ze-Lin Wang Ling Tan Yu-Fei Zhao Yu-Fei Song Pardeep Singh Pankaj Raizada Deli Jiang Di Li R.A.Geioushy Jizhen Ma Jintao Zhang Song Hu Rongjuan Feng Gang Liu Minghua Liu Zhenhua Li Mingfei Shao Neng Li Jiahe Peng Wee-Jun Ong Nikolay Kornienko Zhenyu Xing Xiujun Fan Jianmin Ma 《Chinese Chemical Letters》 SCIE CAS CSCD 2019年第12期2065-2088,共24页
Environmental catalysis has drawn a great deal ofattention due to its clean ways to produce useful chemicals or carry out some chemical processes.Photocatalysis and electrocatalysis play important roles in these field... Environmental catalysis has drawn a great deal ofattention due to its clean ways to produce useful chemicals or carry out some chemical processes.Photocatalysis and electrocatalysis play important roles in these fields.They can decompose and remove organic pollutants from the aqueous environment,and prepare some fine chemicals.Moreover,they also can carry out some important reactions,such as 02 reduction reaction(ORR),O2 evolution reaction(OER),H2 evolution reaction(HER),CO2 reduction reaction(C02 RR),and N2 fixation(NRR).For catalytic reactions,it is the key to develop high-performance catalysts to meet the demand fortargeted reactions.In recentyears,two-dimensional(2 D) materials have attracted great interest in environmental catalysis due to their unique layered structures,which offer us to make use of their electronic and structural characteristics.Great progress has been made so far,including graphene,black phosphorus,oxides,layered double hydroxides(LDHs),chalcogenides,bismuth-based layered compounds,MXenes,metal organic frameworks(MOFs),covalent organic frameworks(COFs),and others.This content drives us to invite many famous groups in these fields to write the roadmap on two-dimensional nanomaterials for environmental catalysis.We hope that this roadmap can give the useful guidance to researchers in future researches,and provide the research directions. 展开更多
关键词 two-dimensional materials Graphene Black phosphorus C3N4 Metal organic frameworks MXenes
原文传递
Wearable Biodevices Based on Two-Dimensional Materials:From Flexible Sensors to Smart Integrated Systems 被引量:1
8
作者 Yingzhi Sun Weiyi He +3 位作者 Can Jiang Jing Li Jianli Liu Mingjie Liu 《Nano-Micro Letters》 2025年第5期207-255,共49页
The proliferation of wearable biodevices has boosted the development of soft,innovative,and multifunctional materials for human health monitoring.The integration of wearable sensors with intelligent systems is an over... The proliferation of wearable biodevices has boosted the development of soft,innovative,and multifunctional materials for human health monitoring.The integration of wearable sensors with intelligent systems is an overwhelming tendency,providing powerful tools for remote health monitoring and personal health management.Among many candidates,two-dimensional(2D)materials stand out due to several exotic mechanical,electrical,optical,and chemical properties that can be efficiently integrated into atomic-thin films.While previous reviews on 2D materials for biodevices primarily focus on conventional configurations and materials like graphene,the rapid development of new 2D materials with exotic properties has opened up novel applications,particularly in smart interaction and integrated functionalities.This review aims to consolidate recent progress,highlight the unique advantages of 2D materials,and guide future research by discussing existing challenges and opportunities in applying 2D materials for smart wearable biodevices.We begin with an in-depth analysis of the advantages,sensing mechanisms,and potential applications of 2D materials in wearable biodevice fabrication.Following this,we systematically discuss state-of-the-art biodevices based on 2D materials for monitoring various physiological signals within the human body.Special attention is given to showcasing the integration of multi-functionality in 2D smart devices,mainly including self-power supply,integrated diagnosis/treatment,and human–machine interaction.Finally,the review concludes with a concise summary of existing challenges and prospective solutions concerning the utilization of2D materials for advanced biodevices. 展开更多
关键词 two-dimensional material Wearable biodevice Flexible sensor Smart integrated system Healthcare
在线阅读 下载PDF
Coupling Coordination Development and Driving Factors of New Energy Vehicles and Ecological Environment in China 被引量:3
9
作者 XU Zonghuang 《Wuhan University Journal of Natural Sciences》 2025年第1期79-90,共12页
Studying the coupling coordination development of new energy vehicles(NEVs)and the ecological environment in China is helpful in promoting the development of NEVs in the country and is of great significance in promoti... Studying the coupling coordination development of new energy vehicles(NEVs)and the ecological environment in China is helpful in promoting the development of NEVs in the country and is of great significance in promoting high-quality development of new energy in China.This paper constructs an evaluation index system for the development of NEVs and the ecological environment.It uses game theory combining weighting model,particle swarm optimized projection tracking evaluation model,coupling coordination degree model,and machine learning algorithms to calculate and analyze the level of coupling coordination development of NEVs and the ecological environment in China from 2010 to 2021,and identifies the driving factors.The research results show that:(i)From 2010 to 2021,the development index of NEVs in China has steadily increased from 0.085 to 0.634,while the ecological environment level index significantly rose from 0.170 to 0.884,reflecting the continuous development of China in both NEVs and the ecological environment.(ii)From 2010 to 2012,the two systems—new energy vehicle(NEV)development and the ecological environment—were in a period of imbalance and decline.From 2013 to 2016,they underwent a transition period,and from 2017 to 2021,they entered a period of coordinated development showing a trend of benign and continuous improvement.By 2021,they reached a good level of coordination.(iii)Indicators such as the number of patents granted for NEVs,water consumption per unit of GDP,and energy consumption per unit of GDP are the main driving factors affecting the coupling coordination development of NEVs and the ecological environment in China. 展开更多
关键词 new energy vehicles(NEVs) ecological environment coupling coordination development machine learning driving factors
原文传递
Obtaining Electromagnetic Properties of Multi-Type Media in Realistic Environments:State-of-the-Art and Prospects 被引量:2
10
作者 Guo Lantu Guan Ke +5 位作者 Liu Ting He Danping Zhang Haixia Zhu Qiuming Lu Jun Zhang Minggao 《China Communications》 2025年第1期25-40,共16页
To meet the requirements of electromagnetic(EM)theory and applied physics,this study presents an overview of the state-of-the-art research on obtaining the EM properties of media and points out potential solutions tha... To meet the requirements of electromagnetic(EM)theory and applied physics,this study presents an overview of the state-of-the-art research on obtaining the EM properties of media and points out potential solutions that can break through the bottlenecks of current methods.Firstly,based on the survey of three mainstream approaches for acquiring EM properties of media,we identify the difficulties when implementing them in realistic environments.With a focus on addressing these problems and challenges,we propose a novel paradigm for obtaining the EM properties of multi-type media in realistic environments.Particularly,within this paradigm,we describe the implementation approach of the key technology,namely“multipath extraction using heterogeneous wave propagation data in multi-spectrum cases”.Finally,the latest measurement and simulation results show that the EM properties of multi-type media in realistic environments can be precisely and efficiently acquired by the methodology proposed in this study. 展开更多
关键词 electromagnetic properties of media multi-type media parameter inversion ray tracing realistic environment
在线阅读 下载PDF
Research progress on environmental behavior of arsenic in Qinghai-Tibet Plateau soil 被引量:1
11
作者 Xitong Li Chuangchuang Zhang +5 位作者 Aofan Wang Tieliang Zhang Zeying He Yujie Zhao Wenjing Liu Qiwen Zhou 《Journal of Environmental Sciences》 2025年第7期237-250,共14页
The Qinghai-Tibet Plateau,with its high altitude and cold climate,is one of the most fragile ecological environments in China and is distinguished by its naturally elevated arsenic(As)levels in the soil,largely due to... The Qinghai-Tibet Plateau,with its high altitude and cold climate,is one of the most fragile ecological environments in China and is distinguished by its naturally elevated arsenic(As)levels in the soil,largely due to its rich mineral and geothermal resources.This review provides a comprehensive analysis of As content,focusing on its distribution,environmental migration,and transformation behavior across the plateau.The review further evaluates the distribution of As in different functional areas,revealing that geothermal fields(107.2 mg/kg),mining areas(53.8 mg/kg),and croplands(39.3 mg/kg)have the highest As concentrations,followed by river and lake sediments and adjacent areas(33.1 mg/kg).These elevated levels are primarily attributed to the presence of As-rich minerals,such as arsenopyrite and pyrite.Additionally,human activities,including mining and geothermal energy production,exacerbate the release of As into the environment.The review also highlights the role of localmicroorganisms,particularly those fromthe phyla Proteobacteria and Actinobacteria,which possess As metabolic genes that facilitate As translocation.Given the unique climatic conditions of the plateau,conventionalmethods for As controlmay not be fully effective.However,the review identifies promising remediation strategies that are environmentally adaptable,such as the use of local microorganisms,specific adsorbents,and integrated technologies,which offer potential solutions for managing and utilizing Ascontaminated soils on the plateau. 展开更多
关键词 Qinghai-Tibet Plateau SOIL ARSENIC Migration and transformation Ecological environment
原文传递
Challenges and Innovations in Ideological and Political Education for College Students in the Micro-Public Opinion Environment 被引量:1
12
作者 Haoyue Zhang Shumin Yan 《Journal of Contemporary Educational Research》 2025年第9期218-224,共7页
The micro-public opinion environment,characterized by information fragmentation,instantaneous dissemination,emotional contagion,and diverse values,has profoundly transformed the information acquisition patterns and co... The micro-public opinion environment,characterized by information fragmentation,instantaneous dissemination,emotional contagion,and diverse values,has profoundly transformed the information acquisition patterns and cognitive formation processes of college students.It also poses new challenges and opportunities for innovation in ideological and political education(hereinafter referred to as“IPE”)for college students.Starting from the contemporary value of IPE for college students,this paper analyzes the logical connection between the micro-public opinion environment and IPE,thoroughly examines the core challenges faced by IPE in this context,and proposes specific innovative paths from four perspectives:content,methods,subjects,and mechanisms.The aim is to provide insights for enhancing the pertinence and effectiveness of IPE for college students in the micro-public opinion environment. 展开更多
关键词 Micro-public opinion environment College students Ideological and political education Educational innovation
在线阅读 下载PDF
Rock Magnetic Evidence for the Seismogenic Environment of Large Earthquakes in the Motuo Fault Zone,Eastern Himalayan Syntaxis 被引量:1
13
作者 CAO Yong SUN Zhiming +5 位作者 GAO Yang LIU Jian LI Bin YANG Yuhan YE Hao XU Peng 《Acta Geologica Sinica(English Edition)》 2025年第3期896-907,共12页
Knowledge of the seismogenic environment of fault zones is critical for understanding the processes and mechanisms of large earthquakes.We conducted a rock magnetic study of the fault rocks and protoliths to investiga... Knowledge of the seismogenic environment of fault zones is critical for understanding the processes and mechanisms of large earthquakes.We conducted a rock magnetic study of the fault rocks and protoliths to investigate the seismogenic environment of earthquakes in the Motuo fault zone,in the eastern Himalayan syntaxis.The results indicate that magnetite is the principal magnetic carrier in the fault rocks and protolith,while the protolith has a higher content of paramagnetic minerals than the fault rocks.The fault rocks are characterized by a high magnetic susceptibility relative to the protolith in the Motuo fault zone.This is likely due to the thermal alteration of paramagnetic minerals to magnetite caused by coseismic frictional heating with concomitant hydrothermal fluid circulation.The high magnetic susceptibility of the fault rocks and neoformed magnetite indicate that large earthquakes with frictional heating temperatures>500℃have occurred in the Motuo fault zone in the past,and that the fault maintained an oxidizing environment with weak fluid action during these earthquakes.Our results reveal the seismogenic environment of the Motuo fault zone,and they are potentially important for the evaluation of the regional stability in the eastern Himalayan syntaxis. 展开更多
关键词 rock magnetism frictional heating seismogenic environment Motuo fault zone eastern Himalayan syntaxis
在线阅读 下载PDF
Inhibitory effect of the interlayer of two-dimensional vermiculite on the polysulfide shuttle in lithium-sulfur batteries
14
作者 CHEN Xiaoli LUO Zhihong +3 位作者 XIONG Yuzhu WANG Aihua CHEN Xue SHAO Jiaojing 《无机化学学报》 北大核心 2025年第8期1661-1671,共11页
A functional interlayer based on two-dimensional(2D)porous modified vermiculite nanosheets(PVS)was obtained by acid-etching vermiculite nanosheets.The as-obtained 2D porous nanosheets exhibited a high specific surface... A functional interlayer based on two-dimensional(2D)porous modified vermiculite nanosheets(PVS)was obtained by acid-etching vermiculite nanosheets.The as-obtained 2D porous nanosheets exhibited a high specific surface area of 427 m^(2)·g^(-1)and rich surface active sites,which help restrain polysulfides(LiPSs)through good physi-cal and chemical adsorption,while simultaneously accelerating the nucleation and dissolution kinetics of Li_(2)S,effec-tively suppressing the shuttle effect.The assembled lithium-sulfur batteries(LSBs)employing the PVS-based inter-layer delivered a high initial discharge capacity of 1386 mAh·g^(-1)at 0.1C(167.5 mAh·g^(-1)),long-term cycling stabil-ity,and good rate property. 展开更多
关键词 vermiculite nanosheets two-dimensional materials INTERLAYER shuttle effect lithium-sulfur batteries
在线阅读 下载PDF
Finite-Time Expected Present Value of Operating Costs until Ruin in a Two-Dimensional Risk Model with Periodic Observation
15
作者 TENG Ye XIE Jiayi ZHANG Zhimin 《应用概率统计》 北大核心 2025年第5期748-765,共18页
This paper investigates ruin,capital injection,and dividends for a two-dimensional risk model.The model posits that surplus levels of insurance companies are governed by a perturbed composite Poisson risk model.This m... This paper investigates ruin,capital injection,and dividends for a two-dimensional risk model.The model posits that surplus levels of insurance companies are governed by a perturbed composite Poisson risk model.This model introduces a dependence between the two surplus levels,present in both the associated perturbations and the claims resulting from common shocks.Critical levels of capital injection and dividends are established for each of the two risks.The surplus levels are observed discretely at fixed intervals,guiding decisions on capital injection,dividends,and ruin at these junctures.This study employs a two-dimensional Fourier cosine series expansion method to approximate the finite time expected discounted operating cost until ruin.The ensuing approximation error is also quantified.The validity and accuracy of the method are corroborated through numerical examples.Furthermore,the research delves into the optimal capital allocation problem. 展开更多
关键词 two-dimensional risk model Fourier cosine expansion capital injection DIVIDEND
在线阅读 下载PDF
Exploring the spatially and temporally varying impacts of built environment factors on rail transit ridership 被引量:1
16
作者 HU Mingxing WANG Chunxin 《Journal of Southeast University(English Edition)》 2025年第2期235-243,共9页
This study examined the influence of the built environment surrounding rail stations on rail transit ridership and its spatiotemporal variations,aiming to enhance rail transit operational efficiency and inform station... This study examined the influence of the built environment surrounding rail stations on rail transit ridership and its spatiotemporal variations,aiming to enhance rail transit operational efficiency and inform station planning and development.Data from 159 metro stations in Nanjing,collected over a 14-d period,were analyzed to identify changes in weekday and weekend ridership patterns.The analysis included explanatory variables grouped into three categories:urban spatial variables,socioeconomic vari-ables,and transit service variables.A geographically and temporally weighted regression(GTWR)model was developed,and its performance was compared with that of ordinary least squares(OLS)and geographically weighted regression(GWR)models.The results demonstrated that the GTWR model outperformed others in analyzing the relationship between rail transit ridership and the built environment.In addition,the coefficients of explanatory variables showed significant variation across spatiotemporal dimensions,revealing distinct patterns.Notably,the influence of commuter flows led to more pronounced temporal heterogeneity in the coefficients observed on weekdays.These findings offer valuable insights for optimizing urban public transportation systems and advancing integrated urban rail development. 展开更多
关键词 built environment rail transit ridership spatio-temporal analysis geographically and temporally weighted regression(GTWR)
在线阅读 下载PDF
Research on the Construction of Intellectual Property System and Optimization of Business Environment in China
17
作者 Zhang Xue Lyu Guofu 《科技与法律(中英文)》 2025年第1期125-137,共13页
With the rapid development of globalization and information technology,intellectual property has been one of the key drivers of economic growth,and the construction of intellectual property system has become an import... With the rapid development of globalization and information technology,intellectual property has been one of the key drivers of economic growth,and the construction of intellectual property system has become an important criterion for measuring the quality of business environment.This article is intended to explore the current status of intellectual property system construction in China,the challenges,and its relationship with the business environment,to propose the corresponding countermeasures and suggestions.The study finds that the legal system of intellectual property in China is gradually improving,and judicial and administrative protection are continuously strengthened.However,the challenges still remain such as frequent infringements,rights hard to protect and insufficient international cooperation.These issues not only affect the legitimate rights and interests of innovation entities,but also for the market fairness and the level of the business environment.Therefore,this article proposes that strengthening the perfection of the intellectual property legal system,enhancing intellectual property services and support capabilities,strengthening international cooperation and exchanges,and accelerating the cultivation of composite talents.It aims to provide theoretical references for the construction of intellectual property system and the optimization of the business environment,promote the high-quality development of economy and enhance the global competitiveness of the country. 展开更多
关键词 intellectual property business environment system construction economic development
在线阅读 下载PDF
Deep space environment empowering drug design and development
18
作者 FANG Yanpeng FENG Bin +3 位作者 LI Weizheng ZHU Liyong CHEN Fei ZENG Wenbin 《中南大学学报(医学版)》 北大核心 2025年第8期1371-1384,共14页
The unique characteristics of the deep space environment,microgravity,cosmic radiation,and extreme temperature fluctuations,are emerging as major driving forces for pharmaceutical innovation.These factors provide new ... The unique characteristics of the deep space environment,microgravity,cosmic radiation,and extreme temperature fluctuations,are emerging as major driving forces for pharmaceutical innovation.These factors provide new avenues for optimizing drug formulations,improving crystal structure quality,and accelerating the discovery of therapeutic targets.Advances in deep space research not only help overcome critical bottlenecks in terrestrial drug development but also promote progress in structure-based drug design and deepen understanding of cellular stress-response mechanisms.Current progress in space-based pharmaceutical research primarily includes the study of disease mechanisms under microgravity,protein crystallization in microgravity,and drug development utilizing deep space radiation and resources.However,the operational complexity,high costs,and limited data reproducibility of space experiments remain key challenges hindering widespread application.Looking ahead,with the integration of automation,artificial intelligence analysis,and on-orbit manufacturing,deep space drug development is expected to achieve greater scalability and precision,opening a new frontier in biopharmaceutical science. 展开更多
关键词 drug development deep space environment MICROGRAVITY protein crystallization RADIATION
暂未订购
Portable Software Environment for Ultrahigh-Resolution ELM Development on GPUs
19
作者 Dali Wang Peter Schwartz +5 位作者 Fengming Yuan Franklin Eaglebarge Danial Riccuito Peter Thornton Chris Layton Qinglei Cao 《Journal of Computer and Communications》 2025年第2期28-36,共9页
This paper presents our endeavors in developing the large-scale, ultra-high-resolution E3SM Land Model (uELM), specifically designed for exascale computers furnished with accelerators such as Nvidia GPUs. The uELM is ... This paper presents our endeavors in developing the large-scale, ultra-high-resolution E3SM Land Model (uELM), specifically designed for exascale computers furnished with accelerators such as Nvidia GPUs. The uELM is a sophisticated code that substantially relies on High-Performance Computing (HPC) environments, necessitating particular machine and software configurations. To facilitate community-based uELM developments employing GPUs, we have created a portable, standalone software environment preconfigured with uELM input datasets, simulation cases, and source code. This environment, utilizing Docker, encompasses all essential code, libraries, and system software for uELM development on GPUs. It also features a functional unit test framework and an offline model testbed for comprehensive numerical experiments. From a technical perspective, the paper discusses GPU-ready container generations, uELM code management, and input data distribution across computational platforms. Lastly, the paper demonstrates the use of environment for functional unit testing, end-to-end simulation on CPUs and GPUs, and collaborative code development. 展开更多
关键词 E3SM Land Model Ultrahigh-Resolution ELM Portable Software environment GPU-Ready environment
在线阅读 下载PDF
Influence of ultrafine cement on cement-soil in peat soil environment of Dianchi Lake
20
作者 CAO Jing SUN Huafeng +5 位作者 HUANG Siyang KONG Cheng LIU Fangyi LIU Fuhua TIAN Lin ZHU Weiming 《土木与环境工程学报(中英文)》 北大核心 2025年第2期1-12,共12页
Treatment of peat soil foundation in Yunnan surrounding Dianchi and Erhai Lakes poses complex problems for engineering projects.It is insufficient to rely on ordinary cement to reinforce peat soil.In order to make the... Treatment of peat soil foundation in Yunnan surrounding Dianchi and Erhai Lakes poses complex problems for engineering projects.It is insufficient to rely on ordinary cement to reinforce peat soil.In order to make the reinforcement reliable,this experiment mixed(ultrafine cement)UFC into ordinary cement to form a composite solidify agent.This study aimed to analyze the influence of UFC proportion on the strength of cement-soil in the peat soil environment.Unconfined compressive strength(UCS)and scanning electron microscope(SEM)tests were conducted on samples soaked for 28 and 90 days,respectively.The test results show that without considering the effects of Humic Acid(HA)and Fulvic Acid(FA),incorporating UFC can significantly improve the UCS of cement-soil.The rapid hydration of the fine particles generates a large number of cementitious products,improves the cohesion of the soil skeleton,and fills the pores.However,when the proportion of UFC increases,the aggregate structure formed by a larger quantity of fine particles reduces the hydration rate and degree of cement hydration,making the UCS growth rate of cement-soil insignificant.In the peat soil environment,HA significantly weakened the UCS of cement-soil in both physical and chemical aspects.However,UFC can mitigate the adverse effect of HA on cement-soil by its small particle size,high surface energy,and solid binding ability.In addition,FA has a positive effect on the UCS of cement-soil soaked for 28 days and 90 days.The UFC addition could promote the enhancement effect of FA on cement-soil UCS.SEM test results showed that cement hydration products increased significantly with the increase of UFC proportion,and cementation between hydration products and soil particles was enhanced.The size and connectivity of cement-soil pores were significantly reduced,thereby improving cement-soil structural integrity. 展开更多
关键词 peat soil environment ultrafine cement(UFC) cement-soil strength test MICROSTRUCTURE
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部