6,012 research outputs found
Enhanced microhardness of nanocrystalline carbon nanotube-reinforced Cu composite using planar shock-wave compaction
No full textPlanar shock-wave compaction (SWC), at a peak pressure of similar to 15 GPa, was used to fabricate 90% dense carbon nanotube-reinforced-Cu composite (SWC-CNT/Cu). Transmission electron microscopy analysis of SWC-CNT/Cu revealed retention of nanoscale size Cu grains, and the presence of shear bands and homogeneous dispersion of CNTs in the Cu matrix. These findings explain the significantly enhanced hardness observed. A Vickers hardness and nanoindentation test for SWC-CNT/Cu indicated enhanced microhardness of 1190 and 1794 MPa, respectively, proving the efficiency of the SWC technique. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.This work was financially supported by Defense Acquisition
Program Administration and Agency for Defense
Development under the contract UD060006AD
and the Korea Research Foundation Grant funded by
the Korean Government (MOEHRD) (KRF-2005-005-
J09701)
Observation on pathogenicity and epizootiology of Penaeus-monodon baculovirus (MBV) in cultured shrimp in Taiwan.
No full textInterfacial Reactions of Sn-Zn, Sn-Zn-Al, and Sn-Zn-Bi Solder Balls with Au/Ni Pad in BGA Package
No full textThe interfacial reactions of Sn-Zn and Sn-Zn-Al solder balls with Au/Ni surface finish under aging at 150\ue2 were investigated. With microstructure evolution, quantitative analysis, elemental distribution by X-ray color mapping from an electron probe microanalyzer (EPMA), the reaction procedure of phase transformation was proposed. During the reflow, Au dissolved into the solder balls and reacted with Zn to form \uce\ub3-Au3Zn7. As aging time increased, \uce\ub3-Au3Zn7 transformed to \uce\ub33-AuZn4. Finally, Zn precipitated near the Au-Zn intermetallic compound. On the other hand, Zn reacted with the Ni layer and formed Ni5Zn21. But the Al-Au-Zn IMC formed at the interface of Sn-Zn-Al solder balls, the reaction of Ni with Zn was inhibited. Even though the aging time increased to 50 days, no Ni5Zn21 was observed.
The Joule effect was more apparent than the electromigration in the biased solder balls. First of all, the new phase (Au, Ni)Zn4 was proposed in the biased condition and in 175\ue2aging. Secondly, the thickness of the Ni5Zn21 IMC were the same between the anode and the cathode. Finally, We directly measure the temperature of the biased solder balls which was up to 173\ue2
An internal variable approach to superplasticity of microduplex Pb-Sn alloys
No full textThe superplastic deformation behavior of microduplex Pb-Sn alloys has been investigated in this study. The effect of shape and volume fraction of constituent phases was examined within the framework of the recently proposed internal variable theory of structural superplasticity. A series of load relaxation and tensile tests as well as the observation of deformed surface using the technique of in-situ straining in a scanning electron microscope were conducted on Pb-Sn alloys at room temperature. The flow curves obtained from load relaxation tests of the superplastic Pb-Sn eutectic alloy were shown to consist of the contributions from interface sliding (IS) and the accommodating plastic deformation, regardless of grain sizes. The IS behavior could be described as a Viscous flow process characterized by the power index value of M-g = 0.5. From a series of surface observation during tensile tests, it was found that the value of M-g was attributed to the onset of intense phase boundary sliding (PBS). Superplasticity of hypoeutectic alloy (Pb-40 wt.% Sn), which is comparable to that of superplastic eutectic alloy, appeared to be superior to that of hypereutectic alloy (Pb-80 wt.% Sn).X111sciescopu
Immune concept of human papillomaviruses and related antigens in local cancer milieu of human cervical neoplasia.
No full textPurification and biochemical characteristics of occlusion body of Penaeus-monodon-type baculovirus (MBV).
No full textClinical experience with intra-aortic balloon counterpulsation over 10 years: A retrospective cohort study of 459 patients.
No full text
Studies on virogenesis and cyto-pathology of Penaeus-monodon baculovirus (MBV) in the giant tiger prawn (Penaeus-monodon) and the red tail prawn (Penaeus-penicillatus).
No full text- …
