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L.R. Testardi 《Solid State Communications》1975,17(7):871-874
The temperature dependence of the superconducting critical current density Jc(T) in zero applied field from 4.2 K to Tc has been measured for 15 films of Nb-Ge with varying composition, deposition conditions, and radiation damage. The results show (i) the enhanced superconductivity observed in stoichiometric Nb3Ge as well as nonstoichiometric films is “bulk like” rather than filamentary, (ii) a simple correlation of the form which is reasonably independent of how the Tc has been achieved, and (iii) some additional evidence that the enhanced Tc of the films is not due to their chemical composition alone. 相似文献
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The resistive superconducting transition width in Nb3Ge after defect producing 4He bombardment shows unusual structure including an oscillatory variation of ? at the onset to superconductivity. 相似文献
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The change in reflectivity of a transporming sample of V3Si between 19 and 11.5 K exhibits not only the expected superconducting gap behavior (at 4 < ?ω < 6 meV) but unusual structure between 6 and 25 meV. One possible cause is the Holstein absorption process which would indicate an unexpected peak in the phonon parameter α2F at 6 ± 2 meV. Data at 19 and 30 K show that no change in reflectivity due to the structural transformation (~ 21 K) occurs to within ≈ over the same energy range. 相似文献
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We have investigated the elastic properties of several one-dimensional compounds using a vibrating reed technique. A model calculation shows that a vanishing Young's modulus will occur for elastic one-dimensionality. TTF-TCNQ exhibits a small modulus which decreases with increasing temperature extrapolating to zero at T ≈ 500–700K. The uniaxial stress dependence of the metal-insulator transition temperature is calculated to be . KCP shows a much higher modulus and a phase transformation at ~ 35 K. 相似文献
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Theresa Hague Andrea Petroczi Paul LR Andrews James Barker Declan P Naughton 《Chemistry Central journal》2010,4(1):2
This is a correction to the following paper: Hague T, Petroczi A, Andrews PR, Barker J, Naughton DP: Determination of metal
ion content of beverages and estimation of target hazard quotients: a comparative study. Chem Central J 2008, 2:13. 相似文献
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Theresa Hague Andrea Petroczi Paul LR Andrews James Barker Declan P Naughton 《Chemistry Central journal》2008,2(1):13
Background
Considerable research has been directed towards the roles of metal ions in nutrition with metal ion toxicity attracting particular attention. The aim of this study is to measure the levels of metal ions found in selected beverages (red wine, stout and apple juice) and to determine their potential detrimental effects via calculation of the Target Hazard Quotients (THQ) for 250 mL daily consumption. 相似文献9.
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G.S. Brown L.R. Testardi J.H. Wernick A.B. Hallak T.H. Geballe 《Solid State Communications》1977,23(12):875-878
We have measured the Extended X-ray Absorption Fine Structure (EXAFS) spectra for superconducting thin films of Nb3Ge prepared at variable deposition temperature by sputtering and electron beam coevaporation. As the deposition temperature is varied from 1050 K to 875 K, the film structure changes continuously from the A15 phase to a quasi-amorphous phase. This amorphous phase is characterized by a mean Ge-Nb distance of 2.66 A, as compared to the A15 distance, 2.87 A. The mean coordination of the Ge sites is reduced from 12 to 8±2, and the mean square spread in Ge-Nb distances (thermal + spatial) has decreased by only 0.01 A2. 相似文献