In this paper a telescope remote control experiment, based on the embedded internet platform-TINI (Tiny Internet Interface)is described.With developing a set of applications, the control of a small telescope equipped with servo system is succeeded.
Abstract Microstructure and creep strength evolution in the ruptured 2.6 wt% W G115 specimens after creep tests were investigated under stresses of 120∼200 MPa at 650 °C. The growth of the lath during the creep tests was accompanied with the coarsening of second phase particles and the reduction of dislocation density. The tempered martensitic lath structure (TMLS) transformed into polygonal sub-grain structure when the pinning force due to the precipitates was lower than about 0.68 MPa. The Laves phase particles were irregular during the short-term creep and grew to be equiaxed shape after long-term creep.
The thermal fatigue behavior of multicomponent Al-7Si-0.3Mg alloys in four different treatment states at typical temperature amplitudes 20 °C→350 °C was studied. The morphology of the second phase particles and crack propagation, and distribution characteristics of dislocations in the thermal fatigue specimens of multicomponent Al-7Si-0.3Mg alloys, were analyzed by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDAX spectrum), and transmission electron microscopy (TEM). The influencing factors, the process, and the mechanism of thermal fatigue crack propagation were mainly studied. The results show that under the same temperature amplitude, the thermal fatigue properties and dislocation densities of the new aluminum alloy and the new aluminum alloy under T6 heat treatment are significantly higher than that of the multicomponent Al-7Si-0.3Mg alloy in cast and refined and modified treatment. The crack growth of thermal fatigue specimen depends on three factors: the temperature amplitude, oxidation, and residual stress. The process of thermal fatigue crack propagation mainly experiences crack initiation and the formation of microcracks, but only a few microcracks continue to expand rapidly or preferentially expand into main cracks. The mechanism of thermal fatigue crack propagation is mainly under the action of thermal stress, the crack tip undergoes a cycle of repeated alternation of sharpening → passivation → sharpening, and the crack continues to move forward from its tip intermittently in the way of propagation → stopping → propagation until fracture failure.
The phenomenon and determinant method of the finished state of coal carbonization in the coking chambers are introduced.Based on the actual production of coke oven of BaoSteel,an experiment has been done,and an experiential formula has been put forward.The result indicated that this formula had a good veracity and can replace artificially judg-ment of the exact time of finished carbonization.All work done have an important reference meaning for the similar coke oven.
The effect of grit-blasting on the oxidation of Ni-based single crystal at 1150 and 1250 °C was studied. The oxide scales formed on the samples with or without grit-blasting were characterized by SEM, XRD, EDS, and EPMA. The results indicate that grit-blasting introduces a plenty of oxide nodules with lamellar structure into the oxide scale of samples after oxidation. The oxide nodule is composed of external and internal part. The external part is multi-layered with outer Cr2O3 layer, inner Al2O3 layer and transitional layer. The internal part includes several alternative alloy layers lack of Al and Al2O3 layer. Hf and Ta segregate at the oxide/alloy and oxide/oxide interface in two parts. Two recrystallized grains are formed under the blasted alloy surface after grit-blasting and heat exposure. The formation of oxide nodules accelerates the development of equiaxed recrystallization. Grit-blasting introduces abundant paths of oxygen diffusion and residual stress into the alloy, promoting the formation of oxide nodules and recrystallization.
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