As with the fast advances in the technologies of big Earth data and information communication,Web-based 3D GIS system has come a long way from a few years ago.These advances reflect in many aspects of 3D GIS such as h...As with the fast advances in the technologies of big Earth data and information communication,Web-based 3D GIS system has come a long way from a few years ago.These advances reflect in many aspects of 3D GIS such as higher real-time performance,enhanced interactivity,more realistic 3D visualization effect and improved user interface.This paper aims to present a comprehensive and upto-date 3D Web GIS for Emergency Response using the current vue.js web application framework and the well-known Cesium APl,taking landslide disaster as an example.Building upon recent advances in WebGL technology,we developed a suite of enhanced 3D spatial analysis functions,including interactive route planning,instant text/image/video messaging being incorporated into both 3D WebGL page and mobile GIS applications,and progressive 3D construction and AR visualization using LiDAR and camera over local emergency network or internet.Moreover,professional functions such as landslide susceptibility mapping,landslide monitoring,spatial temporal contingency plan management,landslide information management,personnel and equipment management,and communication are all implemented and integrated in the 3D GIS system.Most of the functions of the system are implemented using open-source projects,which is beneficial to the development of the 3D GIS research community.展开更多
Using the electrochemical technology to split water molecules to produce hydrogen is the key to obtain green hydrogen for solving the energy crisis. The large-scale application of hydrogen evolution reaction (HER) in ...Using the electrochemical technology to split water molecules to produce hydrogen is the key to obtain green hydrogen for solving the energy crisis. The large-scale application of hydrogen evolution reaction (HER) in water dissociation requires a highly active catalyst. In this paper, the highly dispersed PtCo bimetallic nanoparticles loading on MXene (PtCo/MXene) were prepared by using a step-to-step reduction strategy. The mentioned PtCo/MXene catalyst exhibits a high current density of −100 mA/cm2 in an acidic medium with just a 152 mV overpotential. In addition, the PtCo/MXene catalyst also displays a superior stability. Computational analysis and experimental testing demonstrate that the electronic interaction between Pt and Co can effectively modify the electronic structure of the active site, thereby enhancing the inherent catalytic performance of the material. More importantly, MXene two-dimensional nanosheets can expose more active sites because of their large specific surface area. Furthermore, MXene substrate with excellent electrical conductivity and harmonious interfaces between PtCo and MXene enhance charge transfer efficiency and lower the reaction activation energy.展开更多
Global Navigation Satellite Systems(GNSS)is able to achieve centimeter-level accuracy in open-sky areas.However,their performance declines in urban canyons and outdoor shadow areas.Conversely,commercial Fifth Generati...Global Navigation Satellite Systems(GNSS)is able to achieve centimeter-level accuracy in open-sky areas.However,their performance declines in urban canyons and outdoor shadow areas.Conversely,commercial Fifth Generation Mobile Communications Technology(5G)New Radio(NR)signals,with their wider bandwidth and shorter wavelengths,ofer better range accuracy.To enhance positioning accuracy in challenging environments,we developed a deeply integrated method to combine commercial 5G NR signals with the GNSS.This method involves three key steps:Firstly,we use the Secondary Synchronization Signal to aid the Demodulation Reference Signal(SA-DMRS)in the 5G NR synchronization channel,which aims to improve the tracking loop robustness.Secondly,a Phase-Stabilized Kalman Filter(PSKF)is integrated into the Phase-Locked Loop to boost performance under low Carrier-to-Noise Density Ratio conditions.Lastly,the Extended Kalman Filter(EKF)is applied to fuse 5G and GNSS signals for positioning,and the results are fed back to correct the 5G NR tracking loop.Field tests revealed that SA-DMRS boosted range accuracy by 42.3%,PSKF contributed a further 17%improvement,and GNSS-aided improved the range accuracy by about 33.3%.Compared to the GPS(Global Positioning System)-EKF method,our fusion approach enhances horizontal positioning accuracy by approximately 49.8%,and the vertical positioning accuracy is improved by about 53.3%.Additionally,compared to the GPS-only method,the proposed method can still provide positioning services when there are three usable satellites.Compared with the GNSS-only method,the deep coupled method improved the accuracy in the horizontal and vertical by about 51.2%and 24.0%,respectively.These confrm the method’s efectiveness for accurate and reliable positioning in challenging environments.展开更多
基金supported by the National Key Research and Development Program of China under[Grant number 2019YFC1511304].
文摘As with the fast advances in the technologies of big Earth data and information communication,Web-based 3D GIS system has come a long way from a few years ago.These advances reflect in many aspects of 3D GIS such as higher real-time performance,enhanced interactivity,more realistic 3D visualization effect and improved user interface.This paper aims to present a comprehensive and upto-date 3D Web GIS for Emergency Response using the current vue.js web application framework and the well-known Cesium APl,taking landslide disaster as an example.Building upon recent advances in WebGL technology,we developed a suite of enhanced 3D spatial analysis functions,including interactive route planning,instant text/image/video messaging being incorporated into both 3D WebGL page and mobile GIS applications,and progressive 3D construction and AR visualization using LiDAR and camera over local emergency network or internet.Moreover,professional functions such as landslide susceptibility mapping,landslide monitoring,spatial temporal contingency plan management,landslide information management,personnel and equipment management,and communication are all implemented and integrated in the 3D GIS system.Most of the functions of the system are implemented using open-source projects,which is beneficial to the development of the 3D GIS research community.
基金the Urban Carbon Neutral Science Innovation Foundation of Beijing University of Technology(Nos.048000514122664,048000514122656)the China Postdoctoral Science Foundation(2022M710273)+1 种基金Young Elite Scientists Sponsorship Program by BAST(BYESS2023341)the Beijing Postdoctoral Research Foundation(2022-ZZ-043).
文摘Using the electrochemical technology to split water molecules to produce hydrogen is the key to obtain green hydrogen for solving the energy crisis. The large-scale application of hydrogen evolution reaction (HER) in water dissociation requires a highly active catalyst. In this paper, the highly dispersed PtCo bimetallic nanoparticles loading on MXene (PtCo/MXene) were prepared by using a step-to-step reduction strategy. The mentioned PtCo/MXene catalyst exhibits a high current density of −100 mA/cm2 in an acidic medium with just a 152 mV overpotential. In addition, the PtCo/MXene catalyst also displays a superior stability. Computational analysis and experimental testing demonstrate that the electronic interaction between Pt and Co can effectively modify the electronic structure of the active site, thereby enhancing the inherent catalytic performance of the material. More importantly, MXene two-dimensional nanosheets can expose more active sites because of their large specific surface area. Furthermore, MXene substrate with excellent electrical conductivity and harmonious interfaces between PtCo and MXene enhance charge transfer efficiency and lower the reaction activation energy.
基金The National Natural Science Foundation of China(42171417)Medium-and Long-term Scientifc and Technological Planning Projects for Radio,Television and Audio-Visual Networks+1 种基金Guangxi Science and Technology Major Project(AA22068072)Major Science and Technology Project of Jiangsu Province(No.BG2024003).
文摘Global Navigation Satellite Systems(GNSS)is able to achieve centimeter-level accuracy in open-sky areas.However,their performance declines in urban canyons and outdoor shadow areas.Conversely,commercial Fifth Generation Mobile Communications Technology(5G)New Radio(NR)signals,with their wider bandwidth and shorter wavelengths,ofer better range accuracy.To enhance positioning accuracy in challenging environments,we developed a deeply integrated method to combine commercial 5G NR signals with the GNSS.This method involves three key steps:Firstly,we use the Secondary Synchronization Signal to aid the Demodulation Reference Signal(SA-DMRS)in the 5G NR synchronization channel,which aims to improve the tracking loop robustness.Secondly,a Phase-Stabilized Kalman Filter(PSKF)is integrated into the Phase-Locked Loop to boost performance under low Carrier-to-Noise Density Ratio conditions.Lastly,the Extended Kalman Filter(EKF)is applied to fuse 5G and GNSS signals for positioning,and the results are fed back to correct the 5G NR tracking loop.Field tests revealed that SA-DMRS boosted range accuracy by 42.3%,PSKF contributed a further 17%improvement,and GNSS-aided improved the range accuracy by about 33.3%.Compared to the GPS(Global Positioning System)-EKF method,our fusion approach enhances horizontal positioning accuracy by approximately 49.8%,and the vertical positioning accuracy is improved by about 53.3%.Additionally,compared to the GPS-only method,the proposed method can still provide positioning services when there are three usable satellites.Compared with the GNSS-only method,the deep coupled method improved the accuracy in the horizontal and vertical by about 51.2%and 24.0%,respectively.These confrm the method’s efectiveness for accurate and reliable positioning in challenging environments.
