Concerning the issue of mine pressure behaviors occurred in fully mechanized caving mining of thick coal seams beneath hard stratum in Datong Mining Area, combined with thin and thick plate theory, the paper utilizes ...Concerning the issue of mine pressure behaviors occurred in fully mechanized caving mining of thick coal seams beneath hard stratum in Datong Mining Area, combined with thin and thick plate theory, the paper utilizes theoretical analysis, similar experiments, numerical simulations and field tests to study the influence of remaining coal pillars in Jurassic system goaf on hard stratum fractures, as well as mine pressure behaviors under their coupling effects. The paper concludes the solution formula of initial fault displacement in hard stratum caused by remaining coal pillars. Experiments prove that coupling effects can enhance mine pressure behaviors on working faces. When inter-layer inferior key strata fractures, mine pressure phenomenon such as significant roof weighting steps and increasing resistance in support.When inter-layer superior key strata fractures, the scope of overlying strata extends to Jurassic system goaf, dual-system stopes cut through, and remaining coal pillars lose stability. As a result, the bottom inferior key strata also lose stability. It causes huge impacts on working face, and the second mine pressure behaviors. These phenomena provide evidence for research on other similar mine strata pressure behaviors occurred in dual-system mines with remaining coal pillars.展开更多
A Multi-channel Oceanographic Fluorescence Lidar(MOFL), with a UV excitation at 355 nm and multiple receiving channels at typical wavelengths of fluorescence from oil spills and chlorophyll-a(Chl-a), has been develope...A Multi-channel Oceanographic Fluorescence Lidar(MOFL), with a UV excitation at 355 nm and multiple receiving channels at typical wavelengths of fluorescence from oil spills and chlorophyll-a(Chl-a), has been developed using the Laser- induced Fluorescence(LIF) technique. The sketch of the MOFL system equipped with a compact multi-channel photomultiplier tube(MPMT) is introduced in the paper. The methods of differentiating the oil fluorescence from the background water fluorescence and evaluating the Chl-a concentration are described. Two field experiments were carried out to investigate the field performance of the system, i.e., an experiment in coastal areas for oil pollution detection and an experiment over the Yellow Sea for Chl-a monitoring. In the coastal experiment, several oil samples and other fluorescence substances were used to analyze the fluorescence spectral characteristics for oil identification, and to estimate the thickness of oil films at the water surface. The experiment shows that both the spectral shape of fluorescence induced from surface water and the intensity ratio of two channels(I495/I405) are essential to determine oil-spill occurrence. In the airborne experiment, MOFL was applied to measure relative Chl-a concentrations in the upper layer of the ocean. A comparison of relative Chl-a concentration measurements by MOFL and the Moderate Resolution Imaging Spectroradiometer(MODIS) indicates that the two datasets are in good agreement. The results show that the MOFL system is capable of monitoring oil spills and Chl-a in the upper layer of ocean water.展开更多
In order to evaluate the nutritional quality of Lota lota(Linnaeus) muscle,the common nutrient components,amino acid composition and fatty acid composition in muscle of wild Lota lota(captured in Hailang reaches of Mu...In order to evaluate the nutritional quality of Lota lota(Linnaeus) muscle,the common nutrient components,amino acid composition and fatty acid composition in muscle of wild Lota lota(captured in Hailang reaches of Mudan River) were determined by routine methods. The results showed that the contents of moisture,crude protein,crude fat and ash were 81. 82%,15. 93%,0. 44% and 1. 06% in fresh muscle of Lota lota,respectively. Totally 17 amino acids,including seven kinds of essential amino acids(EAA),were detected in dry muscle of Lota lota(Linnaeus),accounting for 72. 43% of total dry muscle. The content of EAA was 29. 82%,accounting for 41. 17% of TAA,meeting the amino acid composition of high-quality protein standard required by Food and Agriculture Organization /Word Health Organization(FAO /WHO). There were four delicious amino acids(DAA) in dry muscle,accounting for 28. 34% of total dry weight.The percentage of DAA to TAA was 39. 13% in dry muscle. The contents of C20:5n- 3(EPA) and C22:6n- 3(DHA) in dry muscle were 8. 65% and 20. 32%respectively,which were significantly higher than that of the artificially cultured fish species,such as Oxyeleotris marmorata(EPA:2. 24%,DHA:4. 74%),Spinibarbus sinensis(EPA:0. 87%,DHA:3. 08%) and Glossogobius giuris(EPA: 3. 94%,DHA: 8. 10%). Based on the amino acids score(AAS) and chemical score(CS),the first limited amino acid in Lota lota(Linnaeus) was sulfur-containing amino acid(methionine + cysteine). The essential amino acids index(EAAI) of Lota lota(Linnaeus) was 62.58. It is concluded that Lota lota(Linnaeus) is abundant in amino acids and high-unsaturated fatty acids,and rational in composition of amino acids. Thus,Lota lota(Linnaeus) is a high quality freshwater fish with high nutritional value and health value,possessing good exploitation and utilization prospects.展开更多
In order to develop new basic light-weight refractory raw materials,natural forsterite(<0.045 mm)and magnesite(<0.045 mm)were batched according to the chemical composition of forsterite(2MgO·SiO_(2)),wet mi...In order to develop new basic light-weight refractory raw materials,natural forsterite(<0.045 mm)and magnesite(<0.045 mm)were batched according to the chemical composition of forsterite(2MgO·SiO_(2)),wet milled,semi-dry molded and calcined at different temperatures.Then cylinder samples with diameter of 36 mm were prepared.The effects of the wet milling jar rotation speed,the calcination temperature and the anthracite addition on the properties of the samples were researched.The results show that:when the calcination temperature exceeds 1300℃,all the mineral phases have converted to the desired phases;with the increase of the rotation speed and the calcination temperature,the bulk density of the samples increases,the apparent porosity decreases and the compressive strength improves.By comprehensive consideration,400 r·min^(-1) and 1450℃ are taken as the optimal scheme.High addition of anthracite makes the samples light,so series of light-weight raw materials with uniformly distributed micro-pores can be gained.The light-weight raw materials achieved were used for insulation refractory castables,obtaining good application.展开更多
基金provided by the National Natural Science Foundation of China(No.51104191)the National Natural Science Foundation of China(No.51374258)the Program for Changjiang Scholars and Innovative Research Team in University of China(No.IRT13043)
文摘Concerning the issue of mine pressure behaviors occurred in fully mechanized caving mining of thick coal seams beneath hard stratum in Datong Mining Area, combined with thin and thick plate theory, the paper utilizes theoretical analysis, similar experiments, numerical simulations and field tests to study the influence of remaining coal pillars in Jurassic system goaf on hard stratum fractures, as well as mine pressure behaviors under their coupling effects. The paper concludes the solution formula of initial fault displacement in hard stratum caused by remaining coal pillars. Experiments prove that coupling effects can enhance mine pressure behaviors on working faces. When inter-layer inferior key strata fractures, mine pressure phenomenon such as significant roof weighting steps and increasing resistance in support.When inter-layer superior key strata fractures, the scope of overlying strata extends to Jurassic system goaf, dual-system stopes cut through, and remaining coal pillars lose stability. As a result, the bottom inferior key strata also lose stability. It causes huge impacts on working face, and the second mine pressure behaviors. These phenomena provide evidence for research on other similar mine strata pressure behaviors occurred in dual-system mines with remaining coal pillars.
基金supported by the National High Technology Research and Development Program (2006AA06Z415)the Global Change Research Program of China (2012CB955603)
文摘A Multi-channel Oceanographic Fluorescence Lidar(MOFL), with a UV excitation at 355 nm and multiple receiving channels at typical wavelengths of fluorescence from oil spills and chlorophyll-a(Chl-a), has been developed using the Laser- induced Fluorescence(LIF) technique. The sketch of the MOFL system equipped with a compact multi-channel photomultiplier tube(MPMT) is introduced in the paper. The methods of differentiating the oil fluorescence from the background water fluorescence and evaluating the Chl-a concentration are described. Two field experiments were carried out to investigate the field performance of the system, i.e., an experiment in coastal areas for oil pollution detection and an experiment over the Yellow Sea for Chl-a monitoring. In the coastal experiment, several oil samples and other fluorescence substances were used to analyze the fluorescence spectral characteristics for oil identification, and to estimate the thickness of oil films at the water surface. The experiment shows that both the spectral shape of fluorescence induced from surface water and the intensity ratio of two channels(I495/I405) are essential to determine oil-spill occurrence. In the airborne experiment, MOFL was applied to measure relative Chl-a concentrations in the upper layer of the ocean. A comparison of relative Chl-a concentration measurements by MOFL and the Moderate Resolution Imaging Spectroradiometer(MODIS) indicates that the two datasets are in good agreement. The results show that the MOFL system is capable of monitoring oil spills and Chl-a in the upper layer of ocean water.
基金Supported by National Key Technology R&D Program(2012BAD25B10)
文摘In order to evaluate the nutritional quality of Lota lota(Linnaeus) muscle,the common nutrient components,amino acid composition and fatty acid composition in muscle of wild Lota lota(captured in Hailang reaches of Mudan River) were determined by routine methods. The results showed that the contents of moisture,crude protein,crude fat and ash were 81. 82%,15. 93%,0. 44% and 1. 06% in fresh muscle of Lota lota,respectively. Totally 17 amino acids,including seven kinds of essential amino acids(EAA),were detected in dry muscle of Lota lota(Linnaeus),accounting for 72. 43% of total dry muscle. The content of EAA was 29. 82%,accounting for 41. 17% of TAA,meeting the amino acid composition of high-quality protein standard required by Food and Agriculture Organization /Word Health Organization(FAO /WHO). There were four delicious amino acids(DAA) in dry muscle,accounting for 28. 34% of total dry weight.The percentage of DAA to TAA was 39. 13% in dry muscle. The contents of C20:5n- 3(EPA) and C22:6n- 3(DHA) in dry muscle were 8. 65% and 20. 32%respectively,which were significantly higher than that of the artificially cultured fish species,such as Oxyeleotris marmorata(EPA:2. 24%,DHA:4. 74%),Spinibarbus sinensis(EPA:0. 87%,DHA:3. 08%) and Glossogobius giuris(EPA: 3. 94%,DHA: 8. 10%). Based on the amino acids score(AAS) and chemical score(CS),the first limited amino acid in Lota lota(Linnaeus) was sulfur-containing amino acid(methionine + cysteine). The essential amino acids index(EAAI) of Lota lota(Linnaeus) was 62.58. It is concluded that Lota lota(Linnaeus) is abundant in amino acids and high-unsaturated fatty acids,and rational in composition of amino acids. Thus,Lota lota(Linnaeus) is a high quality freshwater fish with high nutritional value and health value,possessing good exploitation and utilization prospects.
基金The work was supported by Student Research Training Program of Henan University of Science and Technology in 2020(No.2020029).
文摘In order to develop new basic light-weight refractory raw materials,natural forsterite(<0.045 mm)and magnesite(<0.045 mm)were batched according to the chemical composition of forsterite(2MgO·SiO_(2)),wet milled,semi-dry molded and calcined at different temperatures.Then cylinder samples with diameter of 36 mm were prepared.The effects of the wet milling jar rotation speed,the calcination temperature and the anthracite addition on the properties of the samples were researched.The results show that:when the calcination temperature exceeds 1300℃,all the mineral phases have converted to the desired phases;with the increase of the rotation speed and the calcination temperature,the bulk density of the samples increases,the apparent porosity decreases and the compressive strength improves.By comprehensive consideration,400 r·min^(-1) and 1450℃ are taken as the optimal scheme.High addition of anthracite makes the samples light,so series of light-weight raw materials with uniformly distributed micro-pores can be gained.The light-weight raw materials achieved were used for insulation refractory castables,obtaining good application.
