Composite C60-LB films were fabricated by the Langmuir-Blodgett (LB) technique, their micro- structures, micro- and macro-tribological properties were investigated using atomic force microscope/ friction force microsc...Composite C60-LB films were fabricated by the Langmuir-Blodgett (LB) technique, their micro- structures, micro- and macro-tribological properties were investigated using atomic force microscope/ friction force microscope (AFM/FFM). The results showed that in the confined C60-LB films there were two kinds of structures for the special C60 assembly: grain diameters of one kind were in the range of 150 -230 nm; the other was smaller than 20 nm. Mi- cro-tribological studies showed that topographical images of tiny C60 aggregates (<20 nm) were con- sistent with their frictional ones very well, namely, low friction occurred on tiny C60 aggregates compared with fatty chains LB monolayer, and ‘Micro-rolling effect’ was apparent; but for big large ones frictional forces were relatively high and ‘ratchet mechanism’ was seen apparently. Macro-tribological data proved large C60 aggregates had wear resistance and load-carrying capacities and anti-wear lives for com- posite C60-LB films were prolonged greatly with dis- persibility of C60 improved and its grain diameter re- duced. Tiny C60 aggregates were mainly the lubri- cating agents. Friction coefficients of composite C60-LB films gradually reduced with loads increasing having the same friction coefficient-load relations with boundary lubrication films.展开更多
微信小程序凭借其便捷性、轻量化、社交属性及开发成本低等优势,已成为移动应用开发的重要方向。本文基于中国铁塔“通信塔”向“数字塔”转型的实际需求,设计并开发了一款基于微信小程序的LBS(Location Based Services,LBS)定位管理系...微信小程序凭借其便捷性、轻量化、社交属性及开发成本低等优势,已成为移动应用开发的重要方向。本文基于中国铁塔“通信塔”向“数字塔”转型的实际需求,设计并开发了一款基于微信小程序的LBS(Location Based Services,LBS)定位管理系统,用于通信塔站址勘察及外业管理。该系统通过整合地图服务、多坐标系转换及数据交互功能,优化了传统外出作业工作流程,显著提升了勘察效率,节约了30%以上的时间与人力成本。此外,系统通过数据增值服务(如智能导航、多业务集成)拓展了应用场景,为通信基础设施的数字化管理提供了创新解决方案。展开更多
为解决当前行蓄洪区管理和运用存在的管理方式粗放、安全运用手段单一、信息资源管理分散、预警难以全覆盖等问题,提出建设行蓄洪区数字“一张图”,利用卫星遥感、卷帘展示、基于位置服务(Location Based Services,LBS)靶向预警、洪水...为解决当前行蓄洪区管理和运用存在的管理方式粗放、安全运用手段单一、信息资源管理分散、预警难以全覆盖等问题,提出建设行蓄洪区数字“一张图”,利用卫星遥感、卷帘展示、基于位置服务(Location Based Services,LBS)靶向预警、洪水风险推演等技术,基于数字孪生水利的总体架构,打造行蓄洪区基础信息查询、违建巡查管理、安全运用分析、通信预警指挥及运用补偿管理5个典型应用场景,并建设业务后台,提高对行蓄洪区的运行监管能力。行蓄洪区数字“一张图”建成并投入使用后,在支撑安徽省行蓄洪区日常管理及安全运用方面发挥了重要的作用,研究成果可为行蓄洪区管理及数字孪生流域防洪建设、应用,以及全生命周期管理提供可行途径和经验借鉴。展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.90306010,20371015,and 20571024)the Program for New Century Excellent Talents in University(Grant No.NCET-04-0653).
文摘Composite C60-LB films were fabricated by the Langmuir-Blodgett (LB) technique, their micro- structures, micro- and macro-tribological properties were investigated using atomic force microscope/ friction force microscope (AFM/FFM). The results showed that in the confined C60-LB films there were two kinds of structures for the special C60 assembly: grain diameters of one kind were in the range of 150 -230 nm; the other was smaller than 20 nm. Mi- cro-tribological studies showed that topographical images of tiny C60 aggregates (<20 nm) were con- sistent with their frictional ones very well, namely, low friction occurred on tiny C60 aggregates compared with fatty chains LB monolayer, and ‘Micro-rolling effect’ was apparent; but for big large ones frictional forces were relatively high and ‘ratchet mechanism’ was seen apparently. Macro-tribological data proved large C60 aggregates had wear resistance and load-carrying capacities and anti-wear lives for com- posite C60-LB films were prolonged greatly with dis- persibility of C60 improved and its grain diameter re- duced. Tiny C60 aggregates were mainly the lubri- cating agents. Friction coefficients of composite C60-LB films gradually reduced with loads increasing having the same friction coefficient-load relations with boundary lubrication films.
文摘在对享受基于位置服务(LBS)用户进行位置隐私保护时,传统k-匿名技术在执行匿名操作时没有全面考虑时间开销和位置背景信息。针对上述问题,提出了一种基于Alt-Geohash编码的k-匿名位置隐私保护方案(k-anonymous location privacy protection scheme based on Alt-Geohash coding,KLPPS-AGC)。首先,通过位置泛化和Alt-Geohash编码技术实现对历史数据的快速检索;其次,根据历史查询概率筛选出能与用户构建高位置熵的位置;再次,利用海伦公式改善匿名集的位置分散度;最后,构建安全匿名集实现对用户的位置隐私保护。实验证明,该方案拥有较低的时间开销和较高的隐私性。
文摘微信小程序凭借其便捷性、轻量化、社交属性及开发成本低等优势,已成为移动应用开发的重要方向。本文基于中国铁塔“通信塔”向“数字塔”转型的实际需求,设计并开发了一款基于微信小程序的LBS(Location Based Services,LBS)定位管理系统,用于通信塔站址勘察及外业管理。该系统通过整合地图服务、多坐标系转换及数据交互功能,优化了传统外出作业工作流程,显著提升了勘察效率,节约了30%以上的时间与人力成本。此外,系统通过数据增值服务(如智能导航、多业务集成)拓展了应用场景,为通信基础设施的数字化管理提供了创新解决方案。
文摘为解决当前行蓄洪区管理和运用存在的管理方式粗放、安全运用手段单一、信息资源管理分散、预警难以全覆盖等问题,提出建设行蓄洪区数字“一张图”,利用卫星遥感、卷帘展示、基于位置服务(Location Based Services,LBS)靶向预警、洪水风险推演等技术,基于数字孪生水利的总体架构,打造行蓄洪区基础信息查询、违建巡查管理、安全运用分析、通信预警指挥及运用补偿管理5个典型应用场景,并建设业务后台,提高对行蓄洪区的运行监管能力。行蓄洪区数字“一张图”建成并投入使用后,在支撑安徽省行蓄洪区日常管理及安全运用方面发挥了重要的作用,研究成果可为行蓄洪区管理及数字孪生流域防洪建设、应用,以及全生命周期管理提供可行途径和经验借鉴。
