针对干线铁路、城际铁路采用的中国列车控制系统(China train control system,CTCS)系统与城市轨道交通采用的基于通信的列车控制系统(communication based train control system,CBTC)系统互不兼容,阻碍四网融合发展和轨道交通系统整...针对干线铁路、城际铁路采用的中国列车控制系统(China train control system,CTCS)系统与城市轨道交通采用的基于通信的列车控制系统(communication based train control system,CBTC)系统互不兼容,阻碍四网融合发展和轨道交通系统整体运输效率低下的问题,对支持四网融合的列控系统的车载设备、地面设备、重叠区设计、制式切换过程等关键技术进行研究,具体包括列车自动防护技术、列车自动驾驶技术、人机接口技术、列车接口技术的一体化车载设备关键技术,支持列车跨线运行的重叠区地面设备关键技术,支持列车不停车安全、平滑切换制式的重叠区设计技术,并分析列车在重叠区内不停车从CTCS到CBTC制式的互相切换过程。研究结果表明:通过车载设备兼容地面设备实现跨线运行,可以减少地面设备数量,简化系统结构,提高系统安全性、可靠性和可维护性,且具有成本优势;采用一体化车载设备,系统结构简单,设备成本低,对安装空间要求较低,是未来技术的发展方向;提出的兼容CTCS和CBTC的列控系统关键技术可用于指导系统设计、研发和应用,对实现四网融合具有指导意义。展开更多
The rapid development of cross-border e-commerce has brought a potentially huge market. But due to the complexity of logistics, capital flow, the credit mechanism is involved in cross-border electronic commerce, a ser...The rapid development of cross-border e-commerce has brought a potentially huge market. But due to the complexity of logistics, capital flow, the credit mechanism is involved in cross-border electronic commerce, a serious impediment to the further development of China＇s cross-border B2C e-commerce enterprises. In order to better promote the development of cross-border e-commerce, improve the competitiveness of cross-border e-commerce and logistics services, we must pay attention to the construction of cross-border logistics. Therefore, it can be improved and perfected through logistics control, personnel training and so on.展开更多
We report a unique shell margin that differed from the usual shell structure of Pinctada fucata.We observed empty organic envelopes in the prismatic layer and the formation of the nacreous layer in the shell margin.Al...We report a unique shell margin that differed from the usual shell structure of Pinctada fucata.We observed empty organic envelopes in the prismatic layer and the formation of the nacreous layer in the shell margin.All the characteristics of the growing margin indicated that the shell was growing rapidly.To explain this anomaly,we propose the concept of "jumping development".During jumping development,the center of growth in the bivalve shell jumps forward over a short time interval when the position of the mantle changes.Jumping development explains the unusual structure of the anomalous shell and the development of annual growth lines in typical shells.Annual growth lines are the result of a discontinuity in the shell microstructure induced by jumping development.展开更多
文摘针对干线铁路、城际铁路采用的中国列车控制系统(China train control system,CTCS)系统与城市轨道交通采用的基于通信的列车控制系统(communication based train control system,CBTC)系统互不兼容,阻碍四网融合发展和轨道交通系统整体运输效率低下的问题,对支持四网融合的列控系统的车载设备、地面设备、重叠区设计、制式切换过程等关键技术进行研究,具体包括列车自动防护技术、列车自动驾驶技术、人机接口技术、列车接口技术的一体化车载设备关键技术,支持列车跨线运行的重叠区地面设备关键技术,支持列车不停车安全、平滑切换制式的重叠区设计技术,并分析列车在重叠区内不停车从CTCS到CBTC制式的互相切换过程。研究结果表明:通过车载设备兼容地面设备实现跨线运行,可以减少地面设备数量,简化系统结构,提高系统安全性、可靠性和可维护性,且具有成本优势;采用一体化车载设备,系统结构简单,设备成本低,对安装空间要求较低,是未来技术的发展方向;提出的兼容CTCS和CBTC的列控系统关键技术可用于指导系统设计、研发和应用,对实现四网融合具有指导意义。
文摘The rapid development of cross-border e-commerce has brought a potentially huge market. But due to the complexity of logistics, capital flow, the credit mechanism is involved in cross-border electronic commerce, a serious impediment to the further development of China＇s cross-border B2C e-commerce enterprises. In order to better promote the development of cross-border e-commerce, improve the competitiveness of cross-border e-commerce and logistics services, we must pay attention to the construction of cross-border logistics. Therefore, it can be improved and perfected through logistics control, personnel training and so on.
基金supported by the National Natural Science Foundation of China (Grant Nos. U0831001 and 40876068)the National High Technology Research and Development Program of China (Grant Nos. 2010CB126405 and 2010AA09Z405)
文摘We report a unique shell margin that differed from the usual shell structure of Pinctada fucata.We observed empty organic envelopes in the prismatic layer and the formation of the nacreous layer in the shell margin.All the characteristics of the growing margin indicated that the shell was growing rapidly.To explain this anomaly,we propose the concept of "jumping development".During jumping development,the center of growth in the bivalve shell jumps forward over a short time interval when the position of the mantle changes.Jumping development explains the unusual structure of the anomalous shell and the development of annual growth lines in typical shells.Annual growth lines are the result of a discontinuity in the shell microstructure induced by jumping development.
