| 1 | Laser Remelting of Plasma Sprayed NiCrAlY and NiCrAlY-Al_2O_3 Coatings显示文摘Two types of plasma sprayed coatings (NiCrAlY and NiCrAlY-A12O3) were remelted by a 5 kW cw CO2 laser. With increasing laser power and decreasing traverse speed in the ranges of 200-700 W and 5-30 mm/s respectively, the melted track grew in width and depth. In the optimum range of laser parameters, a homogeneous remelted layer without voids, cavities, unmelted particles and microcracks was formed. On the surface of remelted layers, Al203 and YAIO3 were detected. As a result of isothermal oxidation tests, weight gains of laser remelted coatings were obviously lower than that only plasma sprayed, especially laser remelted NiCrAlY-Al2O3 coatings. The effects of laser remelting and incorporation of A12O3 second phase in N1CrAlY matrix on high temperature oxidation resistance were discussed. | Yingna WU, Gang ZHA NC, Bingchun ZHANG, Zhongchao FENG and Yong LIANG Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China Fangjun LIU Key Laboratory for High Energy Density Beam Processing Technology, Beijing Aeronautical Manu | 2001 | Journal of Materials Science & Technology2001，17，5： | 3 |
| 4 | The pre-stack migration imaging technique for damages identification in concrete structures显示文摘Pre-stack migration imaging (PMI) method,which is used in geophysical exploration by the performance of single side detection and visually display,can be used to identify the location,orientation,and severity of damages in concrete structure.In particular,this letter focuses on the experimental study by using a finite number of sensors for further practical applications.A concrete structure with a surface-mounted linear PZT transducers array is illustrated.Three types of damages,horizontal,dipping and V-shaped crack damage,have been studied.A pre-stack reverse time migration technique is used to back-propagate the scattering waves and to image damages in concrete structure.The migration results from the scattering waves of an artificial damage are presented.It is shown that the existence of the damage in concrete structure is correctly revealed through migration process. | Ying Luo,1,Ziping Wang,1,Baiqiang Xu,1,2,and Fuhgwo Yuan 1,3,1) Key Laboratory for Mechanical Structure Damage Detection Technology of China Machinery Industry Federation,Jiangsu University,Zhenjiang 210013,China 2) Faculty of Science,Jiangsu University,Zhenjiang 210013,China 3) Department of Mechanical and Aerospace Engineering,North Carolina State University,Raleigh NC 27695-7921,USA | 2011 | Theoretical & Applied Mechanics Letters2011，1，5： | 0 |
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