In order to investigate the characteristics of re-oxidation of residual coal in goafs in close coal seam mining,scanning electron microscope and infrared spectrometer are used to study the changes of coal microstructu...In order to investigate the characteristics of re-oxidation of residual coal in goafs in close coal seam mining,scanning electron microscope and infrared spectrometer are used to study the changes of coal microstructure and chemical reaction of functional groups of eight coal samples at different ranks.Result shows that after initial oxidation,the surface morphology of pore are different,and the porosity of coal is increased and the oxygen adsorption capacity of coal is improved.The change of coal molecular structure and presence of a large amount of active oxygen-containing functional groups lead to increasing tendency of coal to further oxidation.In addition,the higher lever of the initial oxidation is,the easier the re-oxidation occurs.展开更多
This work aimed at studying the feasibility of calculating the coal-oxygen diffusion properties during the low temperature oxidation process of lignite so as to predict its spontaneous combustion process. Coal samples...This work aimed at studying the feasibility of calculating the coal-oxygen diffusion properties during the low temperature oxidation process of lignite so as to predict its spontaneous combustion process. Coal samples were oxidized in air ambient under different temperatures. Scanning Electron Microscope was used to indicate the surface morphology changes of oxidization. Then, based on fractal theory and flow characteristics, the ffactal dimension of gas diffusion in the pore ways was calculated under different temperature. Considering pore size distribution, connectivity distribution and Fick diffusion mechanisms, the relationship between the gas diffusivity change with pore area ffactal dimension and porosity was investigated, and multiple linear equation of the coal- oxygen diffusion coefficients and pore parameters was obtained. Comparison between the experimental data and model prediction verifies the validiW of the model. The research provides a theoretical basis for the prediction model of coal-oxygen diffusion law.展开更多
Using time-dependent 3D tomography method, the electron density distributions in the low-latitude ionosphere during November 2004 super-storm are reconstructed from GPS observations of joint ground-based IGS network a...Using time-dependent 3D tomography method, the electron density distributions in the low-latitude ionosphere during November 2004 super-storm are reconstructed from GPS observations of joint ground-based IGS network and onboard CHAMP/GRACE satellites. The reconstructed electron densities are validated by satellite in situ measurements of CHAMP and GRACE satellites. It is indicated by computer tomography （CT） reconstructions that the long-lived positive storm phase during the first main phase of the storm （November 8） is mainly attributed to enhancement of electron density in the upper F region above the F2 peak. It is found by the CT imaging that the top-hat-like F2-3 double layers occurred in the equatorial ionization anomaly region during the main phase of the storm （at forenoon of November 8）. The structures of column-like enhanced electron density are found at the time near the minimum of Dst and in the longitudinal sector about 157°E, which extend from the topside ionosphere toward plasmasphere, reaching at least about 2000 km as high. Their footprints stand on the two peaks of the EIA.展开更多
The evolution of energetic outer zone electron fluxes during the strong magnetic storm on September 28, 2002 is investigated based on the observations of SAMPEX and GOES-10 satellites. The observations of both satelli...The evolution of energetic outer zone electron fluxes during the strong magnetic storm on September 28, 2002 is investigated based on the observations of SAMPEX and GOES-10 satellites. The observations of both satellites showed that energetic electron fluxes increased significantly during the storm recovery phase, and reached the maximum on October 6. The 1.5–14 MeV and 2.5–14 MeV electron fluxes observed by SAMPEX peaked around L=3.5 with values of 6×10 2 cm -2 s -1 sr -1 keV -1 and 5×10 3 cm -2 s -1 sr -1 keV -1 , which were about 10 and 8 times the pre-storm values. At the geostationary orbit, the >0.6 MeV and >2 MeV electron fluxes observed by GOES-10 showed enhancement up to 50 and 30 times. The plasma parameters and whistler-mode chorus waves in the outer radiation belt are also analyzed based on the data from Cluster C3 satellite. Cluster C3 satellite went through the outer radiation belt twice from 1 October to 4 October, and observed whistler-mode chorus waves with high intensity (10 -5 –10 -4 nT 2 Hz -1 ). Numerical calculations indicated that the observed chorus waves were in gyro-resonance with the radiation belt electrons. The current observations and calculations provide new evidence for that the gyro-resonance with chorus waves contribute significantly to the buildup of energetic outer zone electron fluxes during storms.展开更多
The planetary radio occultation technique is one of the earliest suggested and achieved methods to detect the planetary atmosphere,and has been conducted by almost every deep space planetary probe.The principles,modul...The planetary radio occultation technique is one of the earliest suggested and achieved methods to detect the planetary atmosphere,and has been conducted by almost every deep space planetary probe.The principles,modules,inversion results and primary analysis of the SHAO Planetary Occultation observation Processing system(SPOPs) are presented in this paper.Utilizing open-loop and closed-loop Doppler residual data of the Mars Express radio occultation experiment provided by ESA PSA and NASA PDS,the temperature,pressure,molecular number density profiles of Martian atmosphere and electron density profiles of the ionosphere are successfully retrieved,and the results are validated by the released radio science level 04 products of the ESA MaRS group.This system can also process the atmosphere radio occultation observations of other planets and theirs natural satellites.The implementation of the planetary radio occultation technique is of significance to China's YH-1 Mars exploration project,as well as for future planetary exploration missions from China.展开更多
Five new diacid amides of di-cholesteryl L-glycinates were designed and prepared.The compounds with linkers containing 0,1, 2,3,or 4 methylene units are denoted as 1,2,3,4,and 5,respectively.Their gelation behaviors i...Five new diacid amides of di-cholesteryl L-glycinates were designed and prepared.The compounds with linkers containing 0,1, 2,3,or 4 methylene units are denoted as 1,2,3,4,and 5,respectively.Their gelation behaviors in 25 solvents were tested as novel low-molecular-mass organic gelators(LMOGs).It was shown that the length of the linker connecting the two-cholesteryl residues in a gelator plays a crucial role in the gelation behavior of the compound.1 gels 11 of the 25 solvents tested at a concentration lower than 1.0%,while 2 gels 17 of the solvents tested.4 and 5,however,gel only 2 and 4 of them,respectively. SEM observation reveals that the lengths of the linkers and the identity of the solvents are the main factors affecting the structures of the aggregates in the gels.Experimentally,a clear linker effect on the microstructures of the gels was observed.As example,the aggregates of 1,2 and 3 in benzene or 1-heptanol adopt structures of thin fibers,rods or lamellas,respectively. Furthermore,it was found that the gelation and aggregation behaviors of 2,3,4,and 5 in DMSO showed an even-odd effect.展开更多
基金the National Key Foundation for Exploring Scientific Instruments of China(No.2012YQ24012705)the National Natural Science Foundation of China(No.51174113)+2 种基金the special fund for Scientific Research Institutes of China(Nos.2013EG122192 and 2014EG122293)CCTEG Innovation Foundation of China(No. 2014MS030)Shenhua Innovation Foundation of China(No. SHGF-13-07)
文摘In order to investigate the characteristics of re-oxidation of residual coal in goafs in close coal seam mining,scanning electron microscope and infrared spectrometer are used to study the changes of coal microstructure and chemical reaction of functional groups of eight coal samples at different ranks.Result shows that after initial oxidation,the surface morphology of pore are different,and the porosity of coal is increased and the oxygen adsorption capacity of coal is improved.The change of coal molecular structure and presence of a large amount of active oxygen-containing functional groups lead to increasing tendency of coal to further oxidation.In addition,the higher lever of the initial oxidation is,the easier the re-oxidation occurs.
基金Supported by the National Natural Science Foundation of China(51204179,51204182)the Natural Science Foundation of Jiangsu Province,China(BK20141242)
文摘This work aimed at studying the feasibility of calculating the coal-oxygen diffusion properties during the low temperature oxidation process of lignite so as to predict its spontaneous combustion process. Coal samples were oxidized in air ambient under different temperatures. Scanning Electron Microscope was used to indicate the surface morphology changes of oxidization. Then, based on fractal theory and flow characteristics, the ffactal dimension of gas diffusion in the pore ways was calculated under different temperature. Considering pore size distribution, connectivity distribution and Fick diffusion mechanisms, the relationship between the gas diffusivity change with pore area ffactal dimension and porosity was investigated, and multiple linear equation of the coal- oxygen diffusion coefficients and pore parameters was obtained. Comparison between the experimental data and model prediction verifies the validiW of the model. The research provides a theoretical basis for the prediction model of coal-oxygen diffusion law.
基金supported by the National Natural Science Foundation of China (Grant Nos. 40974087, 40674078)
文摘Using time-dependent 3D tomography method, the electron density distributions in the low-latitude ionosphere during November 2004 super-storm are reconstructed from GPS observations of joint ground-based IGS network and onboard CHAMP/GRACE satellites. The reconstructed electron densities are validated by satellite in situ measurements of CHAMP and GRACE satellites. It is indicated by computer tomography （CT） reconstructions that the long-lived positive storm phase during the first main phase of the storm （November 8） is mainly attributed to enhancement of electron density in the upper F region above the F2 peak. It is found by the CT imaging that the top-hat-like F2-3 double layers occurred in the equatorial ionization anomaly region during the main phase of the storm （at forenoon of November 8）. The structures of column-like enhanced electron density are found at the time near the minimum of Dst and in the longitudinal sector about 157°E, which extend from the topside ionosphere toward plasmasphere, reaching at least about 2000 km as high. Their footprints stand on the two peaks of the EIA.
基金supported by the National Natural Science Foundation of China (Grant Nos. 40925014, 40874076)
文摘The evolution of energetic outer zone electron fluxes during the strong magnetic storm on September 28, 2002 is investigated based on the observations of SAMPEX and GOES-10 satellites. The observations of both satellites showed that energetic electron fluxes increased significantly during the storm recovery phase, and reached the maximum on October 6. The 1.5–14 MeV and 2.5–14 MeV electron fluxes observed by SAMPEX peaked around L=3.5 with values of 6×10 2 cm -2 s -1 sr -1 keV -1 and 5×10 3 cm -2 s -1 sr -1 keV -1 , which were about 10 and 8 times the pre-storm values. At the geostationary orbit, the >0.6 MeV and >2 MeV electron fluxes observed by GOES-10 showed enhancement up to 50 and 30 times. The plasma parameters and whistler-mode chorus waves in the outer radiation belt are also analyzed based on the data from Cluster C3 satellite. Cluster C3 satellite went through the outer radiation belt twice from 1 October to 4 October, and observed whistler-mode chorus waves with high intensity (10 -5 –10 -4 nT 2 Hz -1 ). Numerical calculations indicated that the observed chorus waves were in gyro-resonance with the radiation belt electrons. The current observations and calculations provide new evidence for that the gyro-resonance with chorus waves contribute significantly to the buildup of energetic outer zone electron fluxes during storms.
基金supported by the Sino-Russian Cooperation "YH-1" Mars Exploration Project (Grant No. 2008AA12A209)the National High-tech Research and Development Program of China (Grant No. 2009AA122206, 2008AA12A210, 2009AA12Z319)the National Nataral Science Foundation of China (Grant No. 10973031)
文摘The planetary radio occultation technique is one of the earliest suggested and achieved methods to detect the planetary atmosphere,and has been conducted by almost every deep space planetary probe.The principles,modules,inversion results and primary analysis of the SHAO Planetary Occultation observation Processing system(SPOPs) are presented in this paper.Utilizing open-loop and closed-loop Doppler residual data of the Mars Express radio occultation experiment provided by ESA PSA and NASA PDS,the temperature,pressure,molecular number density profiles of Martian atmosphere and electron density profiles of the ionosphere are successfully retrieved,and the results are validated by the released radio science level 04 products of the ESA MaRS group.This system can also process the atmosphere radio occultation observations of other planets and theirs natural satellites.The implementation of the planetary radio occultation technique is of significance to China's YH-1 Mars exploration project,as well as for future planetary exploration missions from China.
基金supported by the Ministry of Science and Technology of China (2007AA03Z349)the National Natural Science Foundation of China (20773083, 20902055)
文摘Five new diacid amides of di-cholesteryl L-glycinates were designed and prepared.The compounds with linkers containing 0,1, 2,3,or 4 methylene units are denoted as 1,2,3,4,and 5,respectively.Their gelation behaviors in 25 solvents were tested as novel low-molecular-mass organic gelators(LMOGs).It was shown that the length of the linker connecting the two-cholesteryl residues in a gelator plays a crucial role in the gelation behavior of the compound.1 gels 11 of the 25 solvents tested at a concentration lower than 1.0%,while 2 gels 17 of the solvents tested.4 and 5,however,gel only 2 and 4 of them,respectively. SEM observation reveals that the lengths of the linkers and the identity of the solvents are the main factors affecting the structures of the aggregates in the gels.Experimentally,a clear linker effect on the microstructures of the gels was observed.As example,the aggregates of 1,2 and 3 in benzene or 1-heptanol adopt structures of thin fibers,rods or lamellas,respectively. Furthermore,it was found that the gelation and aggregation behaviors of 2,3,4,and 5 in DMSO showed an even-odd effect.
