The work of the revolution has not yet been completed. Let all my comradescontinue to work hard. --- The Last Words of Dr. Sun Yatsen The Chinese people entered the present century with unforgettable nationalshame. Be...The work of the revolution has not yet been completed. Let all my comradescontinue to work hard. --- The Last Words of Dr. Sun Yatsen The Chinese people entered the present century with unforgettable nationalshame. Beijing was full of smoke of gunpowder in 1900 with the invasion of the al-展开更多
Recently, the area located within the Unfinished Obelisk (UO) archeological site showed numerous seepages and accumulations of groundwater in a small pond located a few meters from the Unfinished Obelisk. The Supreme ...Recently, the area located within the Unfinished Obelisk (UO) archeological site showed numerous seepages and accumulations of groundwater in a small pond located a few meters from the Unfinished Obelisk. The Supreme Council of Antiques sponsored integrated geological, geophysical, and hydrogeological studies to identify the possible sources of groundwater and the optimum technique to manage the groundwater flow system that may jeopardize this invaluable sculpture. The geological units and the prevailing structure have been studied in detail using Landsat imagery and field work over two consecutive seasons. The field studies indicated the development of several fault/joint systems oriented mainly ENE-WSW with clear indications of mineralization and intensive weathering effects along these fabrics. Several resistivity (vertical seismic profile and resistivity imaging) measurements extending down to at least 20 m depth and Radar imaging down to 10 m depth are gathered to investigate the extension of outcrop units and the dominant structures prevailing the near subsurface. Geophysical data indicated the development of at least three hydrostratigraphic units arranged from top to bottom as valley fill, fractured/weathered granite, and slightly fractured to massive granitic unit. In addition, the major faults mapped by resistivity images helped to locate several observation wells and a production well to test the transmissivity across the groundwater system. The results of a pumping test indicated very low aquifer conductivity and the development of an aquitard with preferential vertical flow at the study area. This enforces a local interference through a shallow underground drainage system with sump and pump to maintain low groundwater level at the UO-archeological site.展开更多
Xie Ximing, a 73-year old Beijing resident, describes his life over the past 13 years as ＂busy＂ and ＂happy＂ since he retired from Beijing BeierMachine Tool Works Co. Ltd., a state-owned enterprise. But the machine...Xie Ximing, a 73-year old Beijing resident, describes his life over the past 13 years as ＂busy＂ and ＂happy＂ since he retired from Beijing BeierMachine Tool Works Co. Ltd., a state-owned enterprise. But the machine tool engineer recalls he was not in such jovial spirits when the curtain came down on his working life back in 2005.展开更多
In this paper, by considering the stochastic proces s of the busy period and the idle period, and introducing the unfinished work as a supplementary variable, a new vector Markov process was presented to study th e M...In this paper, by considering the stochastic proces s of the busy period and the idle period, and introducing the unfinished work as a supplementary variable, a new vector Markov process was presented to study th e M/G/1 queue again. Through establishing and solving the density evolution equa tions, the busy-period distribution, and the stationary distributions of waitin g time and queue length were obtained. In addition, the stability condition of th is queue system was given by means of an imbedded renewal process.展开更多
文摘The work of the revolution has not yet been completed. Let all my comradescontinue to work hard. --- The Last Words of Dr. Sun Yatsen The Chinese people entered the present century with unforgettable nationalshame. Beijing was full of smoke of gunpowder in 1900 with the invasion of the al-
文摘Recently, the area located within the Unfinished Obelisk (UO) archeological site showed numerous seepages and accumulations of groundwater in a small pond located a few meters from the Unfinished Obelisk. The Supreme Council of Antiques sponsored integrated geological, geophysical, and hydrogeological studies to identify the possible sources of groundwater and the optimum technique to manage the groundwater flow system that may jeopardize this invaluable sculpture. The geological units and the prevailing structure have been studied in detail using Landsat imagery and field work over two consecutive seasons. The field studies indicated the development of several fault/joint systems oriented mainly ENE-WSW with clear indications of mineralization and intensive weathering effects along these fabrics. Several resistivity (vertical seismic profile and resistivity imaging) measurements extending down to at least 20 m depth and Radar imaging down to 10 m depth are gathered to investigate the extension of outcrop units and the dominant structures prevailing the near subsurface. Geophysical data indicated the development of at least three hydrostratigraphic units arranged from top to bottom as valley fill, fractured/weathered granite, and slightly fractured to massive granitic unit. In addition, the major faults mapped by resistivity images helped to locate several observation wells and a production well to test the transmissivity across the groundwater system. The results of a pumping test indicated very low aquifer conductivity and the development of an aquitard with preferential vertical flow at the study area. This enforces a local interference through a shallow underground drainage system with sump and pump to maintain low groundwater level at the UO-archeological site.
文摘Xie Ximing, a 73-year old Beijing resident, describes his life over the past 13 years as ＂busy＂ and ＂happy＂ since he retired from Beijing BeierMachine Tool Works Co. Ltd., a state-owned enterprise. But the machine tool engineer recalls he was not in such jovial spirits when the curtain came down on his working life back in 2005.
基金Project supported by the National Natural Science Foundation of China(Grant No.70171059)
文摘In this paper, by considering the stochastic proces s of the busy period and the idle period, and introducing the unfinished work as a supplementary variable, a new vector Markov process was presented to study th e M/G/1 queue again. Through establishing and solving the density evolution equa tions, the busy-period distribution, and the stationary distributions of waitin g time and queue length were obtained. In addition, the stability condition of th is queue system was given by means of an imbedded renewal process.
