排序方式: 共有48条查询结果,搜索用时 15 毫秒
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M.H.P. Corrêa A. Vasquez M.I. da Costa P.J. Viccaro C.E.T. Gonçalves da Silva 《Solid State Communications》1981,40(3):211-213
Ordered alloys of Pd3Fe are shown to readily absorbe hydrogen through electrolytic loading. The resultant ternary hydride phase is observed to retain the fcc structure of Pd3Fe with approximately the same lattice constant. The 57Fe hyperfine field determined by Mössbauer spectroscopy is found to be 30% smaller in the hydride compared to Pd3Fe. The reduction appears to be associated with a perturbation of the Pd moment by hydrogen. The results suggest the occupation of one type of interstitial site in the structure. The absence of the site in disordered Pd3Fe would explain the much smaller hydrogen capacity observed for this alloy. 相似文献
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The ternary hydride phases ErFe3Hx (with x=1.5 and 2.7) has been studied by57Fe Mössbauer effect. The spectra show that the spin reorientation temperature is increased by the presence of hydrogen in the ErFe3 lattice and is independent of hydrogen concentration for the two hydrides investigated. A preferential filling of the interstitial sites in the RFe3 structure is indicated by the data.Work supported in part by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Financiadora de Estudos e Projetos (FINEP). 相似文献
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Shaofeng Ran Christian Burger Igors Sics Kyunghwan Yoon Dufei Fang Kwangsok Kim Carlos Avila-Orta Jongkahk Keum Benjamin Chu Benjamin S. Hsiao David Cookson Dave Shultz Myungae Lee Jim Viccaro Yasuo Ohta 《Colloid and polymer science》2004,282(8):802-809
The structural development of a nanocomposite, containing 95 wt% isotactic polypropylene (iPP) and 5 wt% modified carbon nanofiber (MCNF), during fiber spinning was investigated by in situ synchrotron small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) techniques. The modification of carbon nanofibers (CNFs) was accomplished by a chemical surface treatment using in situ polymerization of olefin segments to enhance its compatibility with iPP, where the iPP/MCNF nanocomposite was prepared by twostep blending to ensure the dispersion of MCNF. X-ray results showed that at low spin-draw ratios, the iPP/MCNF nanocomposite fiber exhibited much higher iPP crystalline orientation than the control iPP fiber. At higher spin-draw ratios, the crystalline orientation of the nanocomposite fiber and that of the pure iPP fiber was about the same. The crystallinity of the composite fiber was higher than that of the control iPP fiber, indicating the nucleating effect of the modified carbon nanofibers. The nanocomposite fiber also showed larger long periods at low spin-draw ratios. Measurements of mechanical properties indicated that the nanocomposite fiber with 5 wt% MCNF had much higher tensile strength, modulus and longer elongation to break. The mechanical enhancement can be attributed to the dispersion of MCNF in the matrix, which was confirmed by SEM results.Dedicated to Prof. E D. Fischer on his 75th birthday. 相似文献
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We investigate nonlinear oscillations in a fourth-order partialdifferential equation which models a suspension bridge. Previouswork establishes multiple periodic solutions when a parameterexceeds a certain eigenvalue. In this paper, we use Leray-Schauderdegree theory to prove that if the parameter is increased further,beyond a second eigenvalue, then additional solutions are created. 相似文献
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F.W. Kutzler D.E. Ellis T.I. Morrison G.K. Shenoy P.J. Viccaro P.A. Montano E.H. Appelman L. Stein M.J. Pellin D.M. Gruen 《Solid State Communications》1983,46(11):803-806
X-ray absorption near edge structure (XANES) spectra of gaseous Kr, solid Kr and solid KrF2 have been obtained and compared to differentiate between continuum resonances near the edge and bound state transitions. By comparing experimental and ab initio (MSW-Xα) calculated spectra the influence of environment as well as molecular bonding on XANES is demonstrated. 相似文献
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Cara L Ryan David C Baranowski Babykumari P Chitramuthu Suneil Malik Zhi Li Mingju Cao Sandra Minotti Heather D Durham Denis G Kay Christopher A Shaw Hugh PJ Bennett Andrew Bateman 《BMC neuroscience》2009,10(1):1-22