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From the view of systems science, Agricultural Sustainable Development (ASD) is a complex dynamic system, which consists of many basic factors influencing and acting one another. On the basis of briefty demonstrating fundamental n...
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From the view of systems science, Agricultural Sustainable Development (ASD) is a complex dynamic system, which consists of many basic factors influencing and acting one another. On the basis of briefty demonstrating fundamental notions and intentions about ASD, this paper palces an emphasis on analyzing system structure, basic elements and objects by using system analysis theory. It provides a kind of new clue and method for the theoretical research on ASD.
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The remote sensing image has been widely used in AutoCAD, but AutoCAD lack of the function of remote sensing image processing. In the paper, ObjectARX was used for the secondary development tool, combined with the Image Engine SDK...
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The remote sensing image has been widely used in AutoCAD, but AutoCAD lack of the function of remote sensing image processing. In the paper, ObjectARX was used for the secondary development tool, combined with the Image Engine SDK to realize remote sensing image pixel attribute data acquisition in AutoCAD, which provides critical technical support for AutoCAD environment remote sensing image processing algorithms.
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Most monopropellant propulsion system use highly toxic hydrazine as the propellant in conventional spacecraft. The development of "green" propulsion was initiated as an alternative to hydrazine. One of the "green" propellants is t...
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Most monopropellant propulsion system use highly toxic hydrazine as the propellant in conventional spacecraft. The development of "green" propulsion was initiated as an alternative to hydrazine. One of the "green" propellants is the Hydroxyl ammonium Nitrate (HAN) based monopropellant which is a blend of HAN, water, fuel and other additives. HAN-based propulsion clearly provides numerous benefits over monopropellant hydrazine, including: lower toxic, higher volumetric efficiency, significantly reduced transportation/handling hazards and costs, greatly simplified/shortened pre-launch operations.
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Usually people use the input software to type Chinese language on a computer. The software takes a three-step approach: (1) receive the English keyboard input; (2) convert it to Chinese words; (3) output the words. Traditional Chi...
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Usually people use the input software to type Chinese language on a computer. The software takes a three-step approach: (1) receive the English keyboard input; (2) convert it to Chinese words; (3) output the words. Traditional Chinese spelling correction algorithms focus on the errors in the output Chinese, but ignore the errors introduced in the original keyboard input. These algorithms do not work well because the errors in the output are usually not the type of the typographical errors, which these algorithms are good at. In this paper, we propose a novel Chinese spelling correction model directly targeting at the original keyboard input. We integrate this model to an online Chinese input method, to improve the spelling suggestion feature. Experiments using real-word data show that this model helps the spelling suggestion achieve a 93.3% accuracy.
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摘要 :
Usually people use the input software to type Chinese language on a computer. The software takes a three-step approach: (1) receive the English keyboard input; (2) convert it to Chinese words; (3) output the words. Traditional Chi...
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Usually people use the input software to type Chinese language on a computer. The software takes a three-step approach: (1) receive the English keyboard input; (2) convert it to Chinese words; (3) output the words. Traditional Chinese spelling correction algorithms focus on the errors in the output Chinese, but ignore the errors introduced in the original keyboard input. These algorithms do not work well because the errors in the output are usually not the type of the typographical errors, which these algorithms are good at. In this paper, we propose a novel Chinese spelling correction model directly targeting at the original keyboard input. We integrate this model to an online Chinese input method, to improve the spelling suggestion feature. Experiments using real-word data show that this model helps the spelling suggestion achieve a 93.3% accuracy.
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As a novel thermal protection technique for hypersonic vehicles, Magnetohydrodynamic (MHD) heat shield system has been proved to be of great intrinsic value in the hypersonic field. In order to analyze its effective working condit...
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As a novel thermal protection technique for hypersonic vehicles, Magnetohydrodynamic (MHD) heat shield system has been proved to be of great intrinsic value in the hypersonic field. In order to analyze its effective working condition during the hypersonic reentry flight, a physical model is constructed for the MHD heat shield system equipped with a normal solenoid magnet. By taking the real gas effect into account, numerical simulations are conducted for the thermochemical nonequilibrium MHD flow field around a typical hypersonic reentry vehicle, namely Oribital Reentry Experiment (OREX) capsule. After that, the performances of MHD thermal protection and MHD shock control under different flight conditions are analyzed. Results show that, for the OREX capsule, the MHD heat flux mitigation is not obvious until the magnetic interaction parameter is above 1.0 with a corresponding flight altitude above 55.74 km and a flight Mach number above 17.41. Considering that the magnetic interaction parameters of the high altitude cases are larger, the saturation effect of MHD heat flux mitigation is stronger. Moreover, the performance of MHD shock control is also improved with the increase of flight altitude, but the saturation effect of shock control is absent. The performance of the system can be significantly improved by seeding the inflow with potassium particles. There also exists a saturation effect in the seeding amount, and an adequate seeding mass fraction is suggested to be 0.01.
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摘要 :
As a novel thermal protection technique for hypersonic vehicles, Magnetohydrodynamic (MHD) heat shield system has been proved to be of great intrinsic value in the hypersonic field. In order to analyze its effective working condit...
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As a novel thermal protection technique for hypersonic vehicles, Magnetohydrodynamic (MHD) heat shield system has been proved to be of great intrinsic value in the hypersonic field. In order to analyze its effective working condition during the hypersonic reentry flight, a physical model is constructed for the MHD heat shield system equipped with a normal solenoid magnet. By taking the real gas effect into account, numerical simulations are conducted for the thermochemical nonequilibrium MHD flow field around a typical hypersonic reentry vehicle, namely Oribital Reentry Experiment (OREX) capsule. After that, the performances of MHD thermal protection and MHD shock control under different flight conditions are analyzed. Results show that, for the OREX capsule, the MHD heat flux mitigation is not obvious until the magnetic interaction parameter is above 1.0 with a corresponding flight altitude above 55.74 km and a flight Mach number above 17.41. Considering that the magnetic interaction parameters of the high altitude cases are larger, the saturation effect of MHD heat flux mitigation is stronger. Moreover, the performance of MHD shock control is also improved with the increase of flight altitude, but the saturation effect of shock control is absent. The performance of the system can be significantly improved by seeding the inflow with potassium particles. There also exists a saturation effect in the seeding amount, and an adequate seeding mass fraction is suggested to be 0.01.
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Abstract:In order to ensure the consistency of the images in different waveband, a common aperture ultraviolet
and mid wave infrared dual band microscope is designed.Based on the analysis of the factors that affect the image
consi...
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Abstract:In order to ensure the consistency of the images in different waveband, a common aperture ultraviolet
and mid wave infrared dual band microscope is designed.Based on the analysis of the factors that affect the image
consistency, the condition of the equal focal length is derived.Fitting the curve of the focal length difference
changing with the wavelength, and making the focal length of the two wavebands equal by reasonable matching of
the focal power, thus ensuring the good consistency of different band images.The working range of the optical
system is 0.24~0.28μm and 3~5μm; the field is 0.8mm, the numerical aperture is 0.25,the focal length is 13.86mm,
and the magnification is 10X.The transfer function value of UV is higher than 0.75at the spatial frequency of
37lp/mm, The transfer function value of MWIR is higher than 0.35 at the spatial frequency of 30lp/mm.
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摘要 :
Abstract:In order to ensure the consistency of the images in different waveband, a common aperture ultraviolet
and mid wave infrared dual band microscope is designed.Based on the analysis of the factors that affect the image
con...
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Abstract:In order to ensure the consistency of the images in different waveband, a common aperture ultraviolet
and mid wave infrared dual band microscope is designed.Based on the analysis of the factors that affect the image
consistency, the condition of the equal focal length is derived.Fitting the curve of the focal length difference
changing with the wavelength, and making the focal length of the two wavebands equal by reasonable matching of
the focal power, thus ensuring the good consistency of different band images.The working range of the optical
system is 0.24~0.28μm and 3~5μm; the field is 0.8mm, the numerical aperture is 0.25,the focal length is 13.86mm,
and the magnification is 10X.The transfer function value of UV is higher than 0.75at the spatial frequency of
37lp/mm, The transfer function value of MWIR is higher than 0.35 at the spatial frequency of 30lp/mm.
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In order to verify the strength and working reliability of aerostat system under the condition of greater than 30m/s speed, the paper takes a certain type of tethered balloon with a volume of approximately 6000m~3 as the object to...
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In order to verify the strength and working reliability of aerostat system under the condition of greater than 30m/s speed, the paper takes a certain type of tethered balloon with a volume of approximately 6000m~3 as the object to design a trial protocol of Rocket Sled test to meet the test requirements including low overload, low accelerated velocity and long-endurance, including the engine selection, selecting the optimal ignition scheme, determining the direction of cable aerostat and the brake program of sled trochlea, and the overall structural design. While the rationality and feasibility of the aerostat-rocket sled test program are verified by combining the theoretical calculations manner with comparing with a certain type of drag chute test techniques to aerostat to solve the difficulties in aerostat test under harsh environments (such as large wind speed), which has a certain value in engineering in aerospace, military and other areas.
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