排序方式: 共有32条查询结果,搜索用时 15 毫秒
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Moez Trigui Imen Belhadj Abdelmajid Benamara 《The International Journal of Advanced Manufacturing Technology》2017,88(1-4):219-227
A three-dimensional numerical model is established to study the temperature and fluid flow fields in the twin-wire gas metal arc welding (GMAW) process. The high-speed photography system is used to capture the images of the weld pool during the welding. Based on simulation and experimental results, the weld pool formation, convection, and stability in twin-wire GMAW process are investigated. Both “push-pull” and outward flow patterns exist in the twin-wire GMAW weld pool, which can contribute to decreasing the height of the bulge and increasing the width of the pool. The convection in the weld pool can proceed adequately, the arc force between the leading and trailing arcs is relatively balanced, surface tension normal force is uniform along the liquid channel, and the liquid channel is capillary stable, all of those contribute to the stability of the weld bead. The simulation results are in good agreement with those in the experiment. 相似文献
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Tariq Benamara Piotr Breitkopf Ingrid Lepot Caroline Sainvitu 《Structural and Multidisciplinary Optimization》2016,54(4):843-855
This paper presents a reformulation of the “Gappy Proper Orthogonal Decomposition” (Gappy-POD) multi-fidelity modeling approach and proposes an enrichment criterion associated with an adaptive infill algorithm. The latter is here applied to the study of the flight domain of the RAE-2822 transonic airfoil at two different levels of accuracy to demonstrate its ability to detect areas in a two-dimensional design space where the surrogate model needs improvement to better drive the optimization process. 相似文献
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O. Laguerre S. Benamara D. Remy D. Flick 《International Journal of Heat and Mass Transfer》2009,52(25-26):5691-5700
Heat, moisture transfers and airflow by natural convection in a rectangular cavity containing on line cylinders were studied. The work zone was arranged in such a way that 2D transfer and flow were established. At steady state, temperature, velocity and humidity fields on the symmetry plane were measured in un-humidified and humidified cavity. These results were then used to compare with CFD simulation. The thermal stratification and circular air flow in the cavity was observed. Humidification at the bottom face of cavity contributes to increase air velocity. The influence of radiation near the cold and warm walls is significant. 相似文献
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Jiang Wu Seungyong Lee V.R. Reddy M.O. Manasreh B.D. Weaver M.K. Yakes C.S. Furrow Vas.P. Kunets M. Benamara G.J. Salamo 《Materials Letters》2011,65(23-24):3605-3608
Photoluminescence enhancement due to dipole field from gold nanoparticles was observed at 77 K for GaAs capped InAs quantum dots. The gold nanoparticles were coupled to the surface of the cap layer by using dithiol ligands. The enhancement was investigated as a function of the GaAs capped layer thickness. An order of magnitude enhancement in the emission was observed in samples with a cap thickness of 12 nm. This enhancement however is drastically decreased in samples with a cap thickness of 200 nm. The observed enhancement is interpreted in terms of photon scattering from the large dipole scattering cross section. 相似文献
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Rabehi A. Amrani M. Benamara Z. Akkal B. Ziane A. Guermoui M. Hatem-Kacha A. Monier G. Gruzza B. Bideux L. Robert-Goumet C. 《Semiconductors》2018,52(16):1998-2006
Semiconductors - In this paper, we studied the electrical characteristic of Schottky diodes based on gold contact on nitridated GaAs substrates. The used (100) GaAs substrate is n-type with... 相似文献
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Al2O3-YAG-ZrO2 eutectic ceramic rods of 5 mm in diameter were grown by micro-pulling down technique. The seeding and the solidification rate affect microstructure, morphology, crystallography, and thermal stress of the solidified ceramics. The ternary eutectic grown through zirconia (111) seed had inhomogeneous and irregular cellular microstructures. At the stationary stable regime, the microstructure spacing (λ) depends on the pulling rate (v). Under solidification rate of 0.5 mm.min?1, the rods grown by using eutectic poly-crystal, (100), (111) YAG, and c(0001), A(1?210), M(10?10) sapphire seeds, the YAG and ZrO2 phases are oriented along the <100> direction parallel to the growth direction. The zirconia (111) seeding X-ray diagram eutectic presents additional peaks and the monoclinic ZrO2 phase appears at the solidification rate of 1 mm.min-1. The rods grown through ZrO2 seeding are more stressed than those solidified by using eutectic, YAG and sapphire seeds, respectively. 相似文献
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This study was carried out to gain a better insight into evaporation and condensation phenomena due to natural convection in a domestic refrigerator. An experiment was undertaken in a refrigerator loaded with 40 humid plaster cylinders (50 mm diameter). The weight variation of the cylinders was followed over 12 days and the rate of water evaporation (or condensation for some cylinders) was calculated. This measured experimental rate was compared with one obtained from a CFD simulation which took into account air flow by free convection, heat transfer (convection, conduction and radiation) and mass transfer (water evaporation and condensation). The position of high evaporation or condensation rate was well predicted despite the fact that the simulation most often underestimated the experimental values. Near the cold wall where condensation was observed (or near the warm wall where evaporation was observed), the cylinder temperature was lower (or higher) than that of air. This demonstrates the importance of the radiative exchanges between the walls and the products inside a refrigerator which in turn can explain condensation or dehydration phenomena. 相似文献