Rivers are the basic natural resources for various human activities. For that reason, the river banks have encouraged pioneers to construct their new towns. River transport has always been of vital importance for the ...Rivers are the basic natural resources for various human activities. For that reason, the river banks have encouraged pioneers to construct their new towns. River transport has always been of vital importance for the economy of various nations. This could be done fhrough descriptive and analytic navigation in rivers and navigation at sea specially in confined waters. Vessel traffic services （VTS） system deals with managing ship traffic and suggesting best routes for vessels at busy and confined waters. Nile traffic service （NTS） as a Nile traffic monitoring system established by rivers protective authorities, can be alike to VTS maximum economic returns coming from fiver routes can be recognized with assistance of Nile traffic services which keep significant river information available for all users at all times. It also helps keep waters safer and more controlled by detecting illegal cargo activities the paper aims to re-plan River Nile for using in navigation and transportation due to its significant importance for a country like Egypt.展开更多
Wet dust removal is one of the main technical measures in coal dust control,and coal dust wetting is the key factor to determine the effect of wet dust removal.In order to explore the micro-wetting process of coal dus...Wet dust removal is one of the main technical measures in coal dust control,and coal dust wetting is the key factor to determine the effect of wet dust removal.In order to explore the micro-wetting process of coal dust,this paper uses molecular dynamics simulation to study the micro-wetting process of coal dust in different simulation conditions.The molecular dynamics simulation was carried out under different ensemble,thermodynamic states as well as relaxation pretreatment methods,then the H_(2)O molecular layer and coal dust molecular layer in each simulation were quantitatively analyzed by relative concentration.The research results show that a method for establishing molecular model of lignite is proposed and the 2D periodic surface structure is more reasonable.The surface system of coal-H_(2)O molecule is established by NVT aeration method,where the simulation result is close to the actual coal dust wetting process.The simulation effect of medium and large coal dust-H_(2)O molecular system is better than that of small coal dust-H_(2)O molecular system.This study provides a new solution for changing the empirical method of molecular dynamics simulation of coal system wetting and oversimplification of coal system.展开更多
An algorithm for detecting low-frequency seismic events is developed and applied to the detection of low-frequency events before the 2008 Wenchuan and the 2013 Lushan earthquakes. Continuous vertical-component wavefor...An algorithm for detecting low-frequency seismic events is developed and applied to the detection of low-frequency events before the 2008 Wenchuan and the 2013 Lushan earthquakes. Continuous vertical-component waveforms of some broadband stations in the few months before the Wenchuan and Lushan earthquakes are processed by applying a bandpass filter in 2- 8Hz,and then converted to envelopes with a smoothing time of 10 s window and a median filter with a 20 min window. As a result,teleseismic,long-period noise and local small earthquakes are removed,the filtered amplitude is obviously larger than that of the noise and lasts for a dozen minutes to several hours during a few days in a few stations before the Wenchuan and Lushan earthquakes,respectively. The waveform and envelope are similar to that of a non-volcanic tremor( NVT). There are suspected NVT before the two earthquakes. Preliminary application demonstrates that this algorithm is potentially useful for extracting NVT signals from continuous seismic waveforms.展开更多
文摘Rivers are the basic natural resources for various human activities. For that reason, the river banks have encouraged pioneers to construct their new towns. River transport has always been of vital importance for the economy of various nations. This could be done fhrough descriptive and analytic navigation in rivers and navigation at sea specially in confined waters. Vessel traffic services （VTS） system deals with managing ship traffic and suggesting best routes for vessels at busy and confined waters. Nile traffic service （NTS） as a Nile traffic monitoring system established by rivers protective authorities, can be alike to VTS maximum economic returns coming from fiver routes can be recognized with assistance of Nile traffic services which keep significant river information available for all users at all times. It also helps keep waters safer and more controlled by detecting illegal cargo activities the paper aims to re-plan River Nile for using in navigation and transportation due to its significant importance for a country like Egypt.
基金supported by the National Natural Science Foundation of China(51874290)Jiangsu Province"Qinglan Project"and the Fundamental Research Funds for the Central Universities(2019XKQYMS74).
文摘Wet dust removal is one of the main technical measures in coal dust control,and coal dust wetting is the key factor to determine the effect of wet dust removal.In order to explore the micro-wetting process of coal dust,this paper uses molecular dynamics simulation to study the micro-wetting process of coal dust in different simulation conditions.The molecular dynamics simulation was carried out under different ensemble,thermodynamic states as well as relaxation pretreatment methods,then the H_(2)O molecular layer and coal dust molecular layer in each simulation were quantitatively analyzed by relative concentration.The research results show that a method for establishing molecular model of lignite is proposed and the 2D periodic surface structure is more reasonable.The surface system of coal-H_(2)O molecule is established by NVT aeration method,where the simulation result is close to the actual coal dust wetting process.The simulation effect of medium and large coal dust-H_(2)O molecular system is better than that of small coal dust-H_(2)O molecular system.This study provides a new solution for changing the empirical method of molecular dynamics simulation of coal system wetting and oversimplification of coal system.
基金funded by the National Science & Technology Pillar Program in the 12th "Five-year Plan" Period,China(2012BAKI9B02)
文摘An algorithm for detecting low-frequency seismic events is developed and applied to the detection of low-frequency events before the 2008 Wenchuan and the 2013 Lushan earthquakes. Continuous vertical-component waveforms of some broadband stations in the few months before the Wenchuan and Lushan earthquakes are processed by applying a bandpass filter in 2- 8Hz,and then converted to envelopes with a smoothing time of 10 s window and a median filter with a 20 min window. As a result,teleseismic,long-period noise and local small earthquakes are removed,the filtered amplitude is obviously larger than that of the noise and lasts for a dozen minutes to several hours during a few days in a few stations before the Wenchuan and Lushan earthquakes,respectively. The waveform and envelope are similar to that of a non-volcanic tremor( NVT). There are suspected NVT before the two earthquakes. Preliminary application demonstrates that this algorithm is potentially useful for extracting NVT signals from continuous seismic waveforms.
