Large-scale field shear tests on ten specimens of the red-sandstone embankment at a highway in Hunan,China,were performed to examine mechanical characteristics and parameters of red-sandstone.The curves of thrust-disp...Large-scale field shear tests on ten specimens of the red-sandstone embankment at a highway in Hunan,China,were performed to examine mechanical characteristics and parameters of red-sandstone.The curves of thrust-displacement,failure mode,and shear strength parameters for red-sandstone with different water contents,different compactions,and different grain size distributions were obtained from the tests.A practical procedure of in-situ test for red-sandstone embankment was proposed to normalize the test equipment and test steps.Based on three-dimensional thrust-sliding limit equilibrium method,the formulas for calculating strength parameters of red-sandstone considering three-dimensional sliding surface were inferred.The results show that red-sandstone has typical complete curves of stress-strain,strain softening,which are caused by the special structure of red-sandstone;water content and compaction are important factors for strength and failure mode of red-sandstone;The average value of cohesion and internal friction angle of the specimens calculated by three-dimensional technique are 21.56 kPa and 29.29°,respectively,and those by traditional two-dimensional method are 25.52 kPa and 33.76°,respectively.展开更多
The advantages and disadvantages of various outburst prevention measures inheading face were analyzed.The mechanism of outburst prevention about hydraulic extrusionmeasure was studied, the technological parameters wer...The advantages and disadvantages of various outburst prevention measures inheading face were analyzed.The mechanism of outburst prevention about hydraulic extrusionmeasure was studied, the technological parameters were introduced, and the effectof outburst prevention was investigated.The in-situ experimental results show that thehydraulic extrusion measures are applied in serious outburst mine, not only the stress ofstimulate outburst is eliminated effectively but also the gas in coal seam is released efficiently,the measures get obvious effect on coal and gas outburst prevention, and theroadway driving speed is increased by 1.5 times, implementing a safe and rapid excavation.展开更多
Korapuzha is a short river of 40 km with a drainage area of 624 km^2, flowing from dense forest and empties into the Arabian sea. It is formed by the confluence of two streams Agalapuzha and Punnoorpuzha. In this stud...Korapuzha is a short river of 40 km with a drainage area of 624 km^2, flowing from dense forest and empties into the Arabian sea. It is formed by the confluence of two streams Agalapuzha and Punnoorpuzha. In this study the samples were collected from Agalapuzha, Punnoorpuzha and Korappuzha, Korapuzha estuaries. The temperature and pH were monitored on the site and the remaining parameters were analyzed in the laboratory. The physical quality parameters such as color, odor, appearance and chemical quality parameters such as pH, alkalinity, chloride, nitrate, nitrite, sulphate, ammonia, dissolved oxygen, total solids, total hardness, and iron have been evaluated. Compare the physical and chemical parameters. The physico-chemical analysis shows that the samples have high level of salinity, sulphate, total solids and total hardness. The results show that the water is affected by the intrusion of sea water into the river by excess excavation of sands from river for the construction of buildings and other anthropogenic activities which leads to environmental destruction.展开更多
Dredging plume dispersion studies, use dredging plume models to predict the fate of sediment plumes resulting from dredging activities and dredge spoil disposal. The model results are applied as input to environmental...Dredging plume dispersion studies, use dredging plume models to predict the fate of sediment plumes resulting from dredging activities and dredge spoil disposal. The model results are applied as input to environmental impact assessment of the proposed dredging, particularly those associated with suspended sediments and sedimentation. Model validation and performance are still not resolved because of the difficulty of site measurements and the understanding of the parameters used in the model. This paper presents a 3-D dredging plume model based on the MIKE3 software package to investigate parameters which affect the model performances. As a result of lack of site data for the public domain uses, the model scenarios are designed artificially for sensitive runs to identify the key parameters affecting plume behaviours. The factors include dredging spill rates using different dredging methods, equipment and sediment settling velocities. The influence of wave and wind effects combined with tidal forces on the sediment re-suspended rates and the advection/dispersion scales are also assessed.展开更多
Electron-positron pair production in an arbitrary polarized ultrastrong laser field is investigated in the first order perturbation approximation in which the Volkov states are used for convenient calculation of scatt...Electron-positron pair production in an arbitrary polarized ultrastrong laser field is investigated in the first order perturbation approximation in which the Volkov states are used for convenient calculation of scattering amplitude and cross section. It is found surprisingly that the optimal pair production depends strongly on the polarization. For some cases of field parameters, the optimal field is e11iptically polarized or evenly circularly polarized one, rather than the usual linear polarization as indicated by previous works interesting unexpected features are a/so discussed briefly. Some insights into pair generation are given and some展开更多
Because China has been uniquely successful in pursuing maximum growth and political stability, it now faces new challenges of sustainability. The essence of sustainable development in an increasingly prosperous and co...Because China has been uniquely successful in pursuing maximum growth and political stability, it now faces new challenges of sustainability. The essence of sustainable development in an increasingly prosperous and complex China is to avoid crises. Avoiding crises requires both strategic political guidance of the market in order to avoid economic crises, and modernization of politics in order to avoid societal crises. Government must ensure that the economic base is broadened, that citizens are not exposed to excessive risk by market forces, and that inputs and outputs of production do not degrade or exhaust the environment. Meanwhile, the diversification of Chinese society requires political modernization, including comprehensive expansion of the rule of law, transparency, active citizen participation, and democratization within the Party. While these two directions of reform are different, they depend on one another for their success in the long term.展开更多
基金Project(200612) supported by Hunan Province Transportation Department of China
文摘Large-scale field shear tests on ten specimens of the red-sandstone embankment at a highway in Hunan,China,were performed to examine mechanical characteristics and parameters of red-sandstone.The curves of thrust-displacement,failure mode,and shear strength parameters for red-sandstone with different water contents,different compactions,and different grain size distributions were obtained from the tests.A practical procedure of in-situ test for red-sandstone embankment was proposed to normalize the test equipment and test steps.Based on three-dimensional thrust-sliding limit equilibrium method,the formulas for calculating strength parameters of red-sandstone considering three-dimensional sliding surface were inferred.The results show that red-sandstone has typical complete curves of stress-strain,strain softening,which are caused by the special structure of red-sandstone;water content and compaction are important factors for strength and failure mode of red-sandstone;The average value of cohesion and internal friction angle of the specimens calculated by three-dimensional technique are 21.56 kPa and 29.29°,respectively,and those by traditional two-dimensional method are 25.52 kPa and 33.76°,respectively.
文摘The advantages and disadvantages of various outburst prevention measures inheading face were analyzed.The mechanism of outburst prevention about hydraulic extrusionmeasure was studied, the technological parameters were introduced, and the effectof outburst prevention was investigated.The in-situ experimental results show that thehydraulic extrusion measures are applied in serious outburst mine, not only the stress ofstimulate outburst is eliminated effectively but also the gas in coal seam is released efficiently,the measures get obvious effect on coal and gas outburst prevention, and theroadway driving speed is increased by 1.5 times, implementing a safe and rapid excavation.
文摘Korapuzha is a short river of 40 km with a drainage area of 624 km^2, flowing from dense forest and empties into the Arabian sea. It is formed by the confluence of two streams Agalapuzha and Punnoorpuzha. In this study the samples were collected from Agalapuzha, Punnoorpuzha and Korappuzha, Korapuzha estuaries. The temperature and pH were monitored on the site and the remaining parameters were analyzed in the laboratory. The physical quality parameters such as color, odor, appearance and chemical quality parameters such as pH, alkalinity, chloride, nitrate, nitrite, sulphate, ammonia, dissolved oxygen, total solids, total hardness, and iron have been evaluated. Compare the physical and chemical parameters. The physico-chemical analysis shows that the samples have high level of salinity, sulphate, total solids and total hardness. The results show that the water is affected by the intrusion of sea water into the river by excess excavation of sands from river for the construction of buildings and other anthropogenic activities which leads to environmental destruction.
文摘Dredging plume dispersion studies, use dredging plume models to predict the fate of sediment plumes resulting from dredging activities and dredge spoil disposal. The model results are applied as input to environmental impact assessment of the proposed dredging, particularly those associated with suspended sediments and sedimentation. Model validation and performance are still not resolved because of the difficulty of site measurements and the understanding of the parameters used in the model. This paper presents a 3-D dredging plume model based on the MIKE3 software package to investigate parameters which affect the model performances. As a result of lack of site data for the public domain uses, the model scenarios are designed artificially for sensitive runs to identify the key parameters affecting plume behaviours. The factors include dredging spill rates using different dredging methods, equipment and sediment settling velocities. The influence of wave and wind effects combined with tidal forces on the sediment re-suspended rates and the advection/dispersion scales are also assessed.
基金Supported by the National Natural Science Foundation of China (NNSFC) under Grant Nos. 11175023, 11175020the Fundamental Research Funds for the Central Universities (FRFCU)
文摘Electron-positron pair production in an arbitrary polarized ultrastrong laser field is investigated in the first order perturbation approximation in which the Volkov states are used for convenient calculation of scattering amplitude and cross section. It is found surprisingly that the optimal pair production depends strongly on the polarization. For some cases of field parameters, the optimal field is e11iptically polarized or evenly circularly polarized one, rather than the usual linear polarization as indicated by previous works interesting unexpected features are a/so discussed briefly. Some insights into pair generation are given and some
文摘Because China has been uniquely successful in pursuing maximum growth and political stability, it now faces new challenges of sustainability. The essence of sustainable development in an increasingly prosperous and complex China is to avoid crises. Avoiding crises requires both strategic political guidance of the market in order to avoid economic crises, and modernization of politics in order to avoid societal crises. Government must ensure that the economic base is broadened, that citizens are not exposed to excessive risk by market forces, and that inputs and outputs of production do not degrade or exhaust the environment. Meanwhile, the diversification of Chinese society requires political modernization, including comprehensive expansion of the rule of law, transparency, active citizen participation, and democratization within the Party. While these two directions of reform are different, they depend on one another for their success in the long term.
