A mobile satellite communication system (MSCS) is a device installed on a moving carrier for mobile satellite communication. It can eliminate disturbance and maintain continuous satellite communication when the carrie...
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A mobile satellite communication system (MSCS) is a device installed on a moving carrier for mobile satellite communication. It can eliminate disturbance and maintain continuous satellite communication when the carrier is moving. Because of many advantages of mobile satellite communication, the MSCSs are becoming more and more popular in modern mobile communication. In this paper, a typical ship-mounted MSCS is studied. The dynamic model of the system is derived using the generalized Lagrange method both in the joint space and in the workspace. Based on the dynamic model, a nonlinear computed torque controller with trajectory planning is designed to track an aimed satellite with a satisfied transient response. Simulation results in two different situations are presented to show the tracking performance of the controller.
Nucleate pool boiling heat transfer of micro-pin-fined surface structure is proposed for efficiently cooling electronic components with high heat flux in microgravity,and verified by experiments performed utilizing th...
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Nucleate pool boiling heat transfer of micro-pin-fined surface structure is proposed for efficiently cooling electronic components with high heat flux in microgravity,and verified by experiments performed utilizing the drop tower ***-pin-fins with the dimensions of 50μm×1.0(am （thickness×height）(denoted as Chip PF50-1.0) and the space of 50μm were fabricated on the chip surface by dry etching ***-72 was used as working *** pool boiling on a smooth surface was also tested for *** were conducted in terrestrial gravity before the release of the drop capsule and in short-term microgravity during the free falling in the drop tower Beijing. The facility satisfied the safety criteria to expose the apparatus in the drop capsule to different gravitational environments varying between microgravity（μg）(1.-1. g,g=9.81.m/s) in the free falling period and high-g level in the deceleration recovery system（1. go）.
We use non-equilibrium molecular dynamics simulations to calculate the self-diffusion coefficient, D, of a Lennard Jones fluid over a wide density and temperature range. The change in self-diffusion coefficient with t...
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We use non-equilibrium molecular dynamics simulations to calculate the self-diffusion coefficient, D, of a Lennard Jones fluid over a wide density and temperature range. The change in self-diffusion coefficient with temperature decreases by increasing density. For density ρ＊ = ρσ3 = 0.84 we observe a peak at the value of the self-diffusion coefficient and the critical temperature T＊ = kT/ε = 1.25. The value of the self-diffusion coefficient strongly depends on system size. The data of the self-diffusion coefficient are fitted to a simple analytic relation based on hydrodynamic arguments. This correction scales as N-α, where α is an adjustable parameter and N is the number of particles. It is observed that the values of a 〈 1.provide quite a good correction to the simulation data. The system size dependence is very strong for lower densities, but it is not as strong for higher densities. The self-diffusion coefficient calculated with non-equilibrium molecular dynamic simulations at different temperatures and densities is in good agreement with other calculations fronl the literature.
Boiling is a very complex and illusive process with very high efficiency of heat *** many sub-processes in boiling phenomenon,gravity can be involved and play much important *** reveal its influence,long-term,steady m...
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Boiling is a very complex and illusive process with very high efficiency of heat *** many sub-processes in boiling phenomenon,gravity can be involved and play much important *** reveal its influence,long-term,steady microgravity are ***,the opportunity is much ***,ground-based short-term microgravity experiment becomes an attractive alternative. Experiments of transient pool boiling of highly subcooled FC-72 on a smooth silicon chip with the dimensions of 1.×1.x0.5 mm3 were studied in short-term microgravity condition utilizing the drop tower *** heating currents were switched on near the release of the drop *** bubble behaviors and heat transfer of air-dissolved FC-72 on the silicon chip were obtained at the bulk
An empirical corrosion model for SS31.L in simulated proton exchange membrane fuel cell (PEMFC) environments is developed based on systematic experimental data on the effects of various factors, such as acidity, fluor...
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Thermal impact of the parallel laying of gas and oil pipelines remains unclear though that of two oil pipelines has been relatively well studied. A numerical simulation method combined by finite volume and finite diff...
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Thermal impact of the parallel laying of gas and oil pipelines remains unclear though that of two oil pipelines has been relatively well studied. A numerical simulation method combined by finite volume and finite difference was used to investigate the complex heat transfer in three typical parallel laying patterns between gas and oil pipelines: hot oil pipeline with cold gas pipeline;cold oil pipeline with hot gas pipeline and hot oil pipeline with hot gas pipeline. In terms of these three different parallel laying cases, the present paper analyzed characteristics of the maximum differential temperature range and thermal distribution of oil/gas temperatures at different intervals along pipelines relative to the single laying. The numerical simulation results can provide some guidelines for designs and safe operations of the parallel laying of oil/gas pipelines.
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