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101.
China-type petroleum domains include onshore China and adjacent belts,which is enwrapped by Asia-type petroleum domain. Such small, intensively active continental nucleus did not generate a unified platform by continental overgrowth until the end of the Paleozoic, and was separated by the subducted and closed Tethys Sea during Mesozoic and Neozoic period, resulting in the most complex tectonic features in the world. Within the petroleum domains, the hydrocarbon-bearing Paleozoic, Mesozoic and Neozoic sequences were superimposed in a basin. With an exception of the active continental margin basins, the intra-cratonic basins had disappeared, and the foreland basins and rift basins were different from others in the world, so they can be called China-type basins. 相似文献
102.
J.S.Sun J.Q.Gao Y.Feng Y.W.Luan MOE Key Lab.of Liquid Structure Heredity of Materials Shandong University Ji’nan China Technology Center Ji’nan Iron Steel Group Ji’nan China 《金属学报(英文版)》2004,17(2):189-193
A mathematical model describing the behavior of metal inert gas (MIG) welding isformulated in the paper. By means of numerical simulation, the influence of surface-active elements on fluid flow of MIG weldpool is studied. The calculation resultsshow that by adding surface-active elements, the fluid flow behavior is drasticallychanged and the flow fluid flows from lower to upper in vertical direction at the rearof weldpool (w>0). The physical phenomenon is explained from the viewpoint of fluidflow behavior of weldpool that the properties of weld metal is greatly improved andthe content of diffused hydrogen is reduced, thus providing a basis for developing newwelding materials. 相似文献
103.
Shen Linlin Ji Zhen Bai Li Xu Chen 《电子科学学刊(英文版)》2007,24(6):835-837
A novel Discrete Wavelet Transform (DWT) based Hidden Markov Module (HMM) for face recognition is presented in this letter. To improve the accuracy of HMM based face recognition algorithm, DWT is used to replace Discrete Cosine Transform (DCT) for observation sequence ex- traction. Extensive experiments are conducted on two public databases and the results show that the proposed method can improve the accuracy significantly, especially when the face database is large and only few training images are available. 相似文献
104.
S.Y. Gao Y.Z. Zhang L.K. Shi B.L. Du M.Z. Xi H.Z. Ji 《金属学报(英文版)》2007,20(3):171-180
Laser direct deposition (LDD) of metallic components is an advanced technology of combining CAD/CAM (computer aided design/computer aided manufacturing), high power laser, and rapid prototyping. This technology uses laser beam to melt the powders fed coaxiaUy into the molten pool by the laser beam to fabricate fuUy dense metallic components. The present article mainly studies the LDD of Ti-6Al-4V alloy, which can be used to fabricate aircraft components. The mechanical properties of the Ti-6Al-4V alloy, fabricated by LDD, are obtained using the tension test, and the oxygen content of used powders and deposited specimens are measured. In the present article, it can be seen that the mechanical properties obtained using this method are higher than the ones obtained by casting, and equal to those got by wrought anneal. One aircraft part has been made using the LDD process. Because of this aircraft part, with sophisticated shape, the effect of the laser scanning track on the internal soundness of the deposited part was discussed. 相似文献
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