This study investigates the impact of angular mesh dispersion, scattering albedo, and surface emissivity on the computational accuracy of the Monte Carlo method for solving the radiation heat transfer problem with participating medium in a three-dimensional cylindrical coordinate system under isothermal radiation equilibrium conditions. The relationship between the surface emissivity and the minimum number of beams is quantitatively analyzed by collating the data, and the maximum allowable optical thickness under a certain number of bundles is obtained.
Monte Carlo algorithm’s performance change is studied when collision method and path length method are used as the energy beam tracking method for calculating radiative heat transfer under the same physical property condition.The results show that when the surface emissivity, scattering albedo and dielectric absorptivity are fixed at 0.5 and the average optical thickness of a single mesh is less than 0.1, the surface performance factor of the collision method is stable, but the spatial performance factor decreases with the increase of the average optical thickness, and these changes do not change much with the increase of the number of beams.Under the same conditions, the surface performance factor and the space performance factor decrease with the increase of the average optical thickness.Under the same conditions, the surface performance factor and the space performance factor of the path length method decrease with the increase of the average optical thickness.
GF-2 remote sensing products have been widely used in many fields for its high-quality information, which provides technical support for the the macroeconomic decisions. Atmospheric correction is the necessary part in the data preprocessing of the quantitative high resolution remote sensing, which can eliminate the signal interference in the radiation path caused by atmospheric scattering and absorption, and reducting apparent reflectance into real reflectance of the surface targets. Aiming at the problem that current research lack of atmospheric date which are synchronization and region matching of the surface observation image, this research utilize the MODIS Level 1B synchronous data to simulate synchronized atmospheric condition, and write programs to implementation process of aerosol retrieval and atmospheric correction, then generate a lookup table of the remote sensing image based on the radioactive transfer model of 6S (second simulation of a satellite signal in the solar spectrum) to correct the atmospheric effect of multispectral image from GF-2 satellite PMS-1 payload. According to the correction results, this paper analyzes the pixel histogram of the reflectance spectrum of the 4 spectral bands of PMS-1, and evaluates the correction results of different spectral bands. Then conducted a comparison experiment on the same GF-2 image based on the QUAC. According to the different targets respectively statistics the average value of NDVI, implement a comparative study of NDVI from two different results. The degree of influence was discussed by whether to adopt synchronous atmospheric date. The study shows that the result of the synchronous atmospheric parameters have significantly improved the quantitative application of the GF-2 remote sensing data.
KEYWORDS: Clocks, System on a chip, Signal generators, Stereolithography, Bridges, Electrical engineering, Semiconductors, Electronic design automation, Visualization, Image processing
The new problems of traditional clock design in hierarchical mode were analyzed in this paper and a new method of clock design was proposed. A phase_sync signal was used as a bridge of top-level and sub-design in this method. It effectively prevents the 'damage' to the internal timing of sub-design caused by top-level timing closure. The application of this method avoids reset design of clock divider circuit and reduces the difficulty of physical design
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