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Based on the in-orbit state of the Beidou Navigation Satellites, the state of the satellite's platform and payload is analyzed in this paper. To make customs comprehend the Beidou Satellites more deeply, and to expand its applicat...
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Based on the in-orbit state of the Beidou Navigation Satellites, the state of the satellite's platform and payload is analyzed in this paper. To make customs comprehend the Beidou Satellites more deeply, and to expand its application scope, the analyzed result of the main character data about the satellite's platform and payload is given. The analysis Result of the in-orbit data shows that the Beidou Navigation Satellites have had the ability to supply the demanded services for user in the predefined region.
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摘要 :
Based on the in-orbit state of the Beidou Navigation Satellites, the state of the satellite's platform and payload is analyzed in this paper. To make customs comprehend the Beidou Satellites more deeply, and to expand its applicat...
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Based on the in-orbit state of the Beidou Navigation Satellites, the state of the satellite's platform and payload is analyzed in this paper. To make customs comprehend the Beidou Satellites more deeply, and to expand its application scope, the analyzed result of the main character data about the satellite's platform and payload is given. The analysis Result of the in-orbit data shows that the Beidou Navigation Satellites have had the ability to supply the demanded services for user in the predefined region.
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This paper describes the development of a three-dimensional computational fluid dynamic (CFD) model to study the aerodynamics of an active goaf. The aim of this work is to develop a better understanding of gas flow of an active go...
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This paper describes the development of a three-dimensional computational fluid dynamic (CFD) model to study the aerodynamics of an active goaf. The aim of this work is to develop a better understanding of gas flow of an active goaf so that an optimized ventilation and drainage system can be developed and implemented. Two 3D CFD models of the goaf were developed. The first model used the standard features of the FLUENT CFD code to simulate the goaf gas flow. The second model was developed by using specially written external functions to model the effect of porosity on the aerodynamics of the goaf. The results show a more realistic continuous distribution of porosity, the suction effect of the goaf holes and their influence on the distribution of pressure, and the concentration of oxygen and carbon dioxide.
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This paper describes the development of a threedimensional computational fluid dynamic (CFD) model to study the aerodynamics of an active goaf. The aim of this work is to develop a better understanding of gas flow of an active ...
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This paper describes the development of a threedimensional computational fluid dynamic (CFD) model to study the aerodynamics of an active goaf. The aim of this work is to develop a better understanding of gas flow of an active goaf so that an optimized ventilation and drainage system can be developed and implemented. Two 3D CFD models of the goaf were developed. The first model used the standard features of the FLUENT CFD code to simulate the goaf gas flow. The second model was developed by using specially written external functions to model the effect of porosity on the aerodynamics of the goaf. The results show a more realistic continuous distribution of porosity, the suction effect of the goaf holes and their influence on the distribution of pressure, and the concentration of oxygen and carbon dioxide.
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Nitrification inhibitors (NI) are widely used in fertilization to modify nitrogen (N) transformation in soil for matching crop N requirement and reducing N loss to environments. However, the effects of major NI products in China o...
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Nitrification inhibitors (NI) are widely used in fertilization to modify nitrogen (N) transformation in soil for matching crop N requirement and reducing N loss to environments. However, the effects of major NI products in China on inorganic N transformation in purple soil are poorly quantified. Therefore, incubation experiment was carried out to study the effects of major NI products including Entrench (En), 3,4-dimethylpyrazole phosphate (DMPP) and dicyandiamide (DCD) on inorganic N transformation in typical purple soil which is the predominant soil in Sichuan Basin, China. With the same incubation condition (soil moisture: 70% of water hold capacity at 25℃), the contents of ammonium nitrogen (NH_4~+-N), nitrite nitrogen (NO_3~--N), and pH value were measured, and then the apparent nitrification rate and inhibitory rate of the three nitrification inhibitors were calculated. Results showed that the NI can significantly reduce the acidification rate of the purple soil. And a strong nitrification process was showed in the soil without nitrification inhibitors (CK), with 81.4% of NH_4~+-N disappearing from the mineral nitrogen pool during the whole incubation period of 100 days. Compared with CK treatment, addition of NI products resulted in a reduced disappearance of NH_4~+-N by 9.8% for En, 24.6% for DMPP and 26.1% for DCD, respectively. The nitrification process of nitrogen in soil was obviously inhibited by NI products, with the inhibition rate of 7.1% to 95.8% for DMPP and of 3.8% to 97.2% for DCD, respectively. Thus, the nitrification process was delayed by up to 30 days for these two treatments. The inhibition effect of nitrification process by En product was less than that of DMPP and DCD. Under the recommendation rate of NI products, the nitrification inhibition rates were in the order of DCD (5% w/w)>DMPP (1% w/w)>En (2.4% w/w). We concluded that all the major NI products in China could significantly inhibit the process of nitrification in purple soil. While, DMPP and DCD are superior to En product in maintaining NH_4~+-N, inhibiting nitrification process and reducing acidification of the purple soil.
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Of all risks facing coal mines, spontaneous combustion (sponcom) of coal, resulting from the reaction of coal and other carbonaceous materials with oxygen, is the major safety concern. The heating not only threatens lives but ...
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Of all risks facing coal mines, spontaneous combustion (sponcom) of coal, resulting from the reaction of coal and other carbonaceous materials with oxygen, is the major safety concern. The heating not only threatens lives but also causes delays in production and can seriously damage the resource, making some of it un-mineable and emits toxic and greenhouse gases such as carbon monoxide and carbon dioxide. A number of sponcom incidents have occurred in recent years in Australia coal mines, leading to the closure of a coal mine, major production losses, and safety concerns. The sponcom continues to occur in the Australian coal mines. This paper gives an introduction to the status of the sponcom, describes current sponcom management systems and control technologies, and discusses the future needs to better manage and control the sponcom in the Australian coal mining industry.
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摘要 :
Of all risks facing coal mines, spontaneous combustion (sponcom) of coal, resulting from the reaction of coal and other carbonaceous materials with oxygen, is the major safety concern. The heating not only threatens lives but also...
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Of all risks facing coal mines, spontaneous combustion (sponcom) of coal, resulting from the reaction of coal and other carbonaceous materials with oxygen, is the major safety concern. The heating not only threatens lives but also causes delays in production and can seriously damage the resource, making some of it un-mineable and emits toxic and greenhouse gases such as carbon monoxide and carbon dioxide. A number of sponcom incidents have occurred in recent years in Australia coal mines, leading to the closure of a coal mine, major production losses, and safety concerns. The sponcom continues to occur in the Australian coal mines. This paper gives an introduction to the status of the sponcom, describes current sponcom management systems and control technologies, and discusses the future needs to better manage and control the sponcom in the Australian coal mining industry.
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The direct method of fast desorption test is the preferred method of gas content measurement. The gas content of the coal in place in the ground is determined by summing the gas lost from coring, gas measured during desorption, an...
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The direct method of fast desorption test is the preferred method of gas content measurement. The gas content of the coal in place in the ground is determined by summing the gas lost from coring, gas measured during desorption, and the residual gas in the coal. This paper covers some of the issues in relation to gas diffusion and validation of gas content test results. Two specific aspects of the analysis are included; the relationship of the three gas content components, Q_1, Q_2and Q_3, and the initial gas desorption rate model. The results of 33 direct method tests are summarized inform. These results include data on the gas content of 13th coalbed in Guqiao colliery.
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In this paper, the spatial measurement performance of the Beidou inter-satellite-link is analyzed, including the spatial geometric performance analysis of the static inter-satellite network and the dynamic inter-satellite network ...
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In this paper, the spatial measurement performance of the Beidou inter-satellite-link is analyzed, including the spatial geometric performance analysis of the static inter-satellite network and the dynamic inter-satellite network (including the analysis of the number of ranging) and the accuracy of the in-orbit range measurement of the Beidou experimental satellites.
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In this paper, the spatial measurement performance of the Beidou inter-satellite-link is analyzed, including the spatial geometric performance analysis of the static inter-satellite network and the dynamic inter-satellite network ...
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In this paper, the spatial measurement performance of the Beidou inter-satellite-link is analyzed, including the spatial geometric performance analysis of the static inter-satellite network and the dynamic inter-satellite network (including the analysis of the number of ranging) and the accuracy of the in-orbit range measurement of the Beidou experimental satellites.
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