The influence of enlarged section parameters on pressure transients of high-speed train passing through a tunnel was investigated by numerical simulation.The calculation results obtained by the structured and unstruct...The influence of enlarged section parameters on pressure transients of high-speed train passing through a tunnel was investigated by numerical simulation.The calculation results obtained by the structured and unstructured grid and the experimental results of smooth wall tunnel were verified.Numerical simulation studies were conducted on three tunnel enlarged section parameters,the enlarged section distribution along circumferential direction,the enlarged section area and the enlarged section distribution along tunnel length direction.The calculation results show that the influence of the different enlarged section distributions along tunnel circumferential direction on pressure transients in the tunnel is basically consistent.There is an optimal enlarged section area for the minimum value of the pressure variation amplitude and the average pressure variation in the tunnel.The law of the pressure variation amplitude and the average pressure variation of the enlarged section distribution along tunnel length direction are obtained.展开更多
Based on the data recorded by the regional digital seismic network of Yunnan and using new methods, the short-term variations of the ambient stress field of Yunnan and its adjacent areas are monitored in real time. Wi...Based on the data recorded by the regional digital seismic network of Yunnan and using new methods, the short-term variations of the ambient stress field of Yunnan and its adjacent areas are monitored in real time. With the in-depth analyses of the spatial-temporal evolution of the ambient stress field prior to the 2004, Shuangbai M_S5.0 earthquake, concrete procedures for predicting the three elements of the earthquake are presented.展开更多
Femtosecond time-resolved fluorescence non-collinear optical parametric amplification spec- troscopy can extract the curve of spectral gain from its parametric superfluorescence. This unique spectrum correction method...Femtosecond time-resolved fluorescence non-collinear optical parametric amplification spec- troscopy can extract the curve of spectral gain from its parametric superfluorescence. This unique spectrum correction method enables fluorescence non-collinear optical parametric amplification spectroscopy acquiring the genuine transient fluorescence spectrum of the studied system. In this work we employ fluorescence non-collinear optical parametric amplification spectroscopy technique to study the solvation dynamics of DCM dye in ethanol solution, and confirm that genuine solvation correlation function and shift of peak frequency can be derived from transient fluorescence spectra after the spectral gain correction. It demonstrates that fluorescence non-collinear optical parametric amplification spectroscopy can benefit the research fields, which focuses on both fluorescence intensity dynamics and fluorescence spectral shape evolution.展开更多
In the study and the research of the troposphere, the knowledge about its pressure variation on the height is necessary and important. Of course, exist the sounding to make this work, but not always it is possible to ...In the study and the research of the troposphere, the knowledge about its pressure variation on the height is necessary and important. Of course, exist the sounding to make this work, but not always it is possible to access to sounding data when is necessary, so then, it is important to has others alternatives methods in order to replace it. The troposphere is basically a fluid, susceptible to be studied under the fluid mechanics and thermodynamics of the ideals gases without loss generalities. So, it is possible to study of the atmospheric air like as a continuous perfect gas. These facts are important questions to study the troposphere under the laws and beginning Physics, using its respective equations, in order to get a theoretical model to simulate the behavior of its thermodynamics variables and parameters. Working on this line, it was developed a model in order to simulate the tropospheric pressure variation on the height from its measure on surface data.展开更多
Thermo-gravimetric-analysis(TGA) was used to analyze the combustion characteristics of an oil shale and semi-cokes prepared from it.The effect of prior pyrolysis and TGA heating rate on the combustion process was stud...Thermo-gravimetric-analysis(TGA) was used to analyze the combustion characteristics of an oil shale and semi-cokes prepared from it.The effect of prior pyrolysis and TGA heating rate on the combustion process was studied.Prior pyrolysis affects the initial temperature of mass loss and the ignition temperature.The ignition temperature increases as the volatile content of the sample decreases.TG/DTG curves obtained at different heating rates show that heating rate has little effect on ignition temperature.But the peak of combustion shifts to higher temperatures as the heating rate is increased.The Coats-Redfern integration method was employed to find the combustion-reaction kinetic parameters for the burning of oil shale and oil shale semi-coke.展开更多
The parameter identification model of largr scale chromatography separation process is proposed. The Phase equilibrium constants and lumped mass transfer coefficients of sugar and reducing sugar adsorption on D1, D2 a...The parameter identification model of largr scale chromatography separation process is proposed. The Phase equilibrium constants and lumped mass transfer coefficients of sugar and reducing sugar adsorption on D1, D2 and D3 resins as well as the axial dispersion coefficients of the fluid through packed columns are determined by means of the pulse-response experiment technique with an inert substance as a tracer and the chromatography measuring technique. The elution curve calculated from these parameters is good agreement with the experimental elution curve. The sensitivity analysis of these parameters is carried out, and the ressult shows that the elation curves of chromatography separation are more sensitive to the variations Of the Phase equilibrium relationship than to the variation of the axial dispersion as well as the lumped mass transfer coefficients.展开更多
In this paper,we analyzed the One Foundations relief and reconstruction activities after the Yaan earthquake.The analysis shows that the participation of NGOs in disaster relief activities has undergone different stag...In this paper,we analyzed the One Foundations relief and reconstruction activities after the Yaan earthquake.The analysis shows that the participation of NGOs in disaster relief activities has undergone different stages.In the Jiujiang earthquake,NGOs participation was in the rudimentary stage.In the Wenchuan earthquake,they became one of the active participants.In the Yaan earthquake,they played an active role through a cooperation mechanism.That means NGOs have had the capability of resource mobilization and cooperation with them will improve disaster management capacities,especially in the national significant seismic monitoring and protection regions.展开更多
Because of the importance of gravity waves （GWs） in coupling different atmospheric regions, further studies are necessary to investigate the characteristics of GW propagation in a non-isothermal atmosphere. Using a ...Because of the importance of gravity waves （GWs） in coupling different atmospheric regions, further studies are necessary to investigate the characteristics of GW propagation in a non-isothermal atmosphere. Using a nonlinear numerical model, we simulate the propagation of small amplitude GWs with various wavelengths in different non-isothermal atmospheres. Our re- sults show that the GW vertical wavelength undergoes sharp changes above the stratopause and mesopause region. Specifically for a GW with an initial vertical wavelength of 5 km, the seasonal background temperature structure difference at 50° latitude can cause the vertical wavelength to vary by -2 krn in the mesosphere and by as large as -4.5 km in the lower thermosphere. In addition, the GW paths exhibit great divergence in the height range of -65-110 kin. Our results also show that the variations of GW path, vertical wavelength and horizontal phase velocity are not synchronized in a non-isothermal atmosphere as in an isothermal atmosphere. Despite the fact that all GWs change their characteristics as they propagate upward in a non-isothermal atmosphere, the variations relative to the initial parameters at a reference height are similar for different initial vertical wavelengths. Our results indicate that the changing characteristics of a gravity wave in a non-isothermal atmosphere need to be considered when investigating the relationship of GWs at two different heights.展开更多
基金Project (2016YFB1200602-11) supported by National Key R&D Plan of China
文摘The influence of enlarged section parameters on pressure transients of high-speed train passing through a tunnel was investigated by numerical simulation.The calculation results obtained by the structured and unstructured grid and the experimental results of smooth wall tunnel were verified.Numerical simulation studies were conducted on three tunnel enlarged section parameters,the enlarged section distribution along circumferential direction,the enlarged section area and the enlarged section distribution along tunnel length direction.The calculation results show that the influence of the different enlarged section distributions along tunnel circumferential direction on pressure transients in the tunnel is basically consistent.There is an optimal enlarged section area for the minimum value of the pressure variation amplitude and the average pressure variation in the tunnel.The law of the pressure variation amplitude and the average pressure variation of the enlarged section distribution along tunnel length direction are obtained.
基金the Key Science andTechnology R&D Project of the 10th "Five-Year Plan" of Yunnan Province , entitled "Study of Med- and Short-term Prediction Techniques for Strong Earthquakein Yunnan"(2001NG46) andthe construction of Earthquake Monitoring andPrevention Center of West Yunnan (YN150105T037-045)
文摘Based on the data recorded by the regional digital seismic network of Yunnan and using new methods, the short-term variations of the ambient stress field of Yunnan and its adjacent areas are monitored in real time. With the in-depth analyses of the spatial-temporal evolution of the ambient stress field prior to the 2004, Shuangbai M_S5.0 earthquake, concrete procedures for predicting the three elements of the earthquake are presented.
文摘Femtosecond time-resolved fluorescence non-collinear optical parametric amplification spec- troscopy can extract the curve of spectral gain from its parametric superfluorescence. This unique spectrum correction method enables fluorescence non-collinear optical parametric amplification spectroscopy acquiring the genuine transient fluorescence spectrum of the studied system. In this work we employ fluorescence non-collinear optical parametric amplification spectroscopy technique to study the solvation dynamics of DCM dye in ethanol solution, and confirm that genuine solvation correlation function and shift of peak frequency can be derived from transient fluorescence spectra after the spectral gain correction. It demonstrates that fluorescence non-collinear optical parametric amplification spectroscopy can benefit the research fields, which focuses on both fluorescence intensity dynamics and fluorescence spectral shape evolution.
文摘In the study and the research of the troposphere, the knowledge about its pressure variation on the height is necessary and important. Of course, exist the sounding to make this work, but not always it is possible to access to sounding data when is necessary, so then, it is important to has others alternatives methods in order to replace it. The troposphere is basically a fluid, susceptible to be studied under the fluid mechanics and thermodynamics of the ideals gases without loss generalities. So, it is possible to study of the atmospheric air like as a continuous perfect gas. These facts are important questions to study the troposphere under the laws and beginning Physics, using its respective equations, in order to get a theoretical model to simulate the behavior of its thermodynamics variables and parameters. Working on this line, it was developed a model in order to simulate the tropospheric pressure variation on the height from its measure on surface data.
基金Project CPEUKF08-04 support by the Key Laboratory of Coal Processing and Efficient Utilization, Ministry of Education of China
文摘Thermo-gravimetric-analysis(TGA) was used to analyze the combustion characteristics of an oil shale and semi-cokes prepared from it.The effect of prior pyrolysis and TGA heating rate on the combustion process was studied.Prior pyrolysis affects the initial temperature of mass loss and the ignition temperature.The ignition temperature increases as the volatile content of the sample decreases.TG/DTG curves obtained at different heating rates show that heating rate has little effect on ignition temperature.But the peak of combustion shifts to higher temperatures as the heating rate is increased.The Coats-Redfern integration method was employed to find the combustion-reaction kinetic parameters for the burning of oil shale and oil shale semi-coke.
文摘The parameter identification model of largr scale chromatography separation process is proposed. The Phase equilibrium constants and lumped mass transfer coefficients of sugar and reducing sugar adsorption on D1, D2 and D3 resins as well as the axial dispersion coefficients of the fluid through packed columns are determined by means of the pulse-response experiment technique with an inert substance as a tracer and the chromatography measuring technique. The elution curve calculated from these parameters is good agreement with the experimental elution curve. The sensitivity analysis of these parameters is carried out, and the ressult shows that the elation curves of chromatography separation are more sensitive to the variations Of the Phase equilibrium relationship than to the variation of the axial dispersion as well as the lumped mass transfer coefficients.
基金sponsored by the National Social Science Fund of China "Research on the Status,Efficiencies and the Policy on the National Significant Seismic Monitoring and Protection Regions"(11&ZD054)Policy Research Projects of China Earthquake Administration in 2014 "The Role of NGOs in Earthquake Relief and the Meaning to Policy"
文摘In this paper,we analyzed the One Foundations relief and reconstruction activities after the Yaan earthquake.The analysis shows that the participation of NGOs in disaster relief activities has undergone different stages.In the Jiujiang earthquake,NGOs participation was in the rudimentary stage.In the Wenchuan earthquake,they became one of the active participants.In the Yaan earthquake,they played an active role through a cooperation mechanism.That means NGOs have had the capability of resource mobilization and cooperation with them will improve disaster management capacities,especially in the national significant seismic monitoring and protection regions.
基金supported by the National Natural Science Foundation of China (Grant Nos. 40921063, 41004063, 41074109, 40890165, and 41174127)the National Important Basic Research Project (Grant No. 2011CB811405)+3 种基金the China Postdoctoral Science Foundation (Grant No. 20100470506)supported in part by the Specialized Research Fundthe Open Research Program of the State Key Laboratory of Space Weatherthe National Science Foundation of Unites States grant-ATM-0633418 to Miami University
文摘Because of the importance of gravity waves （GWs） in coupling different atmospheric regions, further studies are necessary to investigate the characteristics of GW propagation in a non-isothermal atmosphere. Using a nonlinear numerical model, we simulate the propagation of small amplitude GWs with various wavelengths in different non-isothermal atmospheres. Our re- sults show that the GW vertical wavelength undergoes sharp changes above the stratopause and mesopause region. Specifically for a GW with an initial vertical wavelength of 5 km, the seasonal background temperature structure difference at 50° latitude can cause the vertical wavelength to vary by -2 krn in the mesosphere and by as large as -4.5 km in the lower thermosphere. In addition, the GW paths exhibit great divergence in the height range of -65-110 kin. Our results also show that the variations of GW path, vertical wavelength and horizontal phase velocity are not synchronized in a non-isothermal atmosphere as in an isothermal atmosphere. Despite the fact that all GWs change their characteristics as they propagate upward in a non-isothermal atmosphere, the variations relative to the initial parameters at a reference height are similar for different initial vertical wavelengths. Our results indicate that the changing characteristics of a gravity wave in a non-isothermal atmosphere need to be considered when investigating the relationship of GWs at two different heights.
