Papers by Keyword: Reverse Monte Carlo

Abstract: A novel near space target optical properties modeling method based on the reverse Monte Carlo optical tracking is proposed. Both the environment characteristics in near space and the light transmission characteristics in different detection platform mode are considered and analysis in detail. The invalid light can be eliminated adaptively in this model. According to the phase relationship of target-observing systems-the sun, the optical properties of the target can be obtained. Some numerical simulations are made to test the accuracy and capability of the proposed modeling method.

Abstract: A fast and accurate infrared radiation calculation method was investigated. Reverse Monte Carlo (RMC) method was adopted to calculate the Infrared (IR) Radiation characteristic of surface. The computational code used Mersenne Twister (MT) method to generate random number, and bounding box method to accelerate computational speed. The Infrared Radiation characteristics of some typical geometric structures were calculated and verified. The effects of emission photons number and mesh number on calculation results were analyzed. The results show the error between calculation value and theoretical value is less than 0.02%. The calculation time is proportional to emission photons number and mesh number.

Abstract: The aerodynamic heating and infrared radiation characteristics of BrahMos supersonic cruise missile were investigated. The aerodynamic heating was simulated using finite volume method, and the infrared radiation characteristics were simulated by reverse Monte Carlo method. Infrared radiation characteristics of missile surface were analyzed in different surface emissivity and flight altitudes, and the effects of environmental radiation and atmospheric attenuation were considered. The results show 8~14μm and 3~5μm environment radiation were approximately 10% and 2.4% of total radiation respectively, when the surface emissivity is 0.3. The proportion of environmental radiation reduces nearly half when the surface emissivity increases by 0.2.

Abstract: We use neutron total scattering measurements with reverse Monte Carlo analysis methods incorporating an atom-swapping algorithm to investigate the short-range Zr/Ti cation ordering at the perovskite crystalloraphic B sites and micro structure within PbZr_0.5Ti_0.5O₃ solid solution at different temperature. Our results show that there is no Zr/Ti ordering at the B sites. TiO₆ and ZrO₆ units are rotated and distorted. The amplitude of rotations of the TiO₆ units is larger than that of the ZrO₆ units, accompanied by more distortions of the angles within the TiO₆ units.

Abstract: We present the modelled local structure for undercooled silicon beginning from its liquid state, ~1730K to ~1550K. The modelling procedure was achieved by using reverse Monte Carlo (RMC) modelling technique fitting to x-ray static structure factors. The calculated radial distribution functions satisfied experimental observes either liquid or undercooled region. To make a detailed analysis on the modelled local environment we have focused on the distributions both average numbers of atoms within first coordination shell and bond angles whereas the uniqueness of model is discussible. In order to construct model that is more close to nature, the minimum and maximum bond lengths and the average coordination number constraints could have been used. The predicted results using RMC technique show that there is a possible structural transition and it slightly transforms into covalent-like bounded open network structure from its metallic structure, while decreasing temperature.