Intelligent transportation system (ITS) has become a popular research topic to meet the increased demands of transportation safety,traffic efficiency,comfort in the journey and environment protection,etc. ITS applicat...Intelligent transportation system (ITS) has become a popular research topic to meet the increased demands of transportation safety,traffic efficiency,comfort in the journey and environment protection,etc. ITS applications impose higher requirements on wireless communication systems. For example,safety-related ITS services must always be low latency and entertainment-related ITS services need high data rate. The ITS dedicated short range communications (DSRC) technology to support the safetyrelated application is still under development, while long term evolution (LTE),as the next generation mobile communication systems,offers an efficient communication platform for ITS information exchange , which can meet most ITS services requirements of latency,data rate as well as communication range. In this paper,based on the time-division duplex (TDD) mode of LTE,i.e. TD-LTE,an enhanced TD-LTE network architecture is introduced to better support safety-related ITS application with low latency requirement,and some enhanced access schemes of TD-LTE are proposed to improve the performance of supporting the high-speed IP-based ITS applications in hotspots. At last,two practical application scenarios of enhanced TD-LTE systems are given.展开更多
Polycarboxylate water-reducing admixture possesses the capability which could meet with the comprehensive performance of high performance concrete used in passenger dedicated line engineering.The problems of polycarbo...Polycarboxylate water-reducing admixture possesses the capability which could meet with the comprehensive performance of high performance concrete used in passenger dedicated line engineering.The problems of polycarboxylates water-reducing admixtures existed in the engineering application of were analyzed.At present the key for polycarboxylates application was to settle the compatibility between the water-reducing admixture and the cement and to keep the quality retention of this admixture.展开更多
基金National Science and Technology Major Project (No.2012ZX03005010-005)
文摘Intelligent transportation system (ITS) has become a popular research topic to meet the increased demands of transportation safety,traffic efficiency,comfort in the journey and environment protection,etc. ITS applications impose higher requirements on wireless communication systems. For example,safety-related ITS services must always be low latency and entertainment-related ITS services need high data rate. The ITS dedicated short range communications (DSRC) technology to support the safetyrelated application is still under development, while long term evolution (LTE),as the next generation mobile communication systems,offers an efficient communication platform for ITS information exchange , which can meet most ITS services requirements of latency,data rate as well as communication range. In this paper,based on the time-division duplex (TDD) mode of LTE,i.e. TD-LTE,an enhanced TD-LTE network architecture is introduced to better support safety-related ITS application with low latency requirement,and some enhanced access schemes of TD-LTE are proposed to improve the performance of supporting the high-speed IP-based ITS applications in hotspots. At last,two practical application scenarios of enhanced TD-LTE systems are given.
文摘Polycarboxylate water-reducing admixture possesses the capability which could meet with the comprehensive performance of high performance concrete used in passenger dedicated line engineering.The problems of polycarboxylates water-reducing admixtures existed in the engineering application of were analyzed.At present the key for polycarboxylates application was to settle the compatibility between the water-reducing admixture and the cement and to keep the quality retention of this admixture.
