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排序方式: 共有106条查询结果,搜索用时 15 毫秒
1.
Bulk superconducting samples of type Tl0.5Pb0.5Sr1.6Ba0.4CaCu2−x
Ru
x
O7−δ, (Tl, Pb)/Sr-1212, with 0.0 ≤ x ≤ 0.525 were prepared by the conventional one-step solid-state reaction technique. The prepared samples were investigated
using X-ray powder diffraction, electrical resistivity and electron paramagnetic resonance (EPR) measurements. Enhancement
of the phase formation, superconducting transition temperature T
c and hole carriers concentration P was observed up to x = 0.075. For x > 0.075, a reverse trend was observed. EPR spectra were measured at different temperatures (120–290 K) for all prepared samples.
The number of spins N participating in the resonance and the paramagnetic susceptibility χ were calculated as a function of both Ru-content and
temperature. N and χ increased as the Ru-content increased. A linear relationship between logN and 1/T was established, from which the activation energy E
a was calculated as a function of the Ru-content. The temperature dependence of χ was fitted according to Curie–Weiss type
of magnetic behavior. Curie constant C, Curie temperature θ, the effective magnetic moment μ and the electronic specific heat γ were estimated as a function of the Ru-content. 相似文献
2.
3.
G. Finch 《Fresenius' Journal of Analytical Chemistry》1914,53(8):528-529
Ohne Zusammenfassung 相似文献
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5.
Baurin N Aboul-Ela F Barril X Davis B Drysdale M Dymock B Finch H Fromont C Richardson C Simmonite H Hubbard RE 《Journal of chemical information and computer sciences》2004,44(6):2157-2166
We have designed four generations of a low molecular weight fragment library for use in NMR-based screening against protein targets. The library initially contained 723 fragments which were selected manually from the Available Chemicals Directory. A series of in silico filters and property calculations were developed to automate the selection process, allowing a larger database of 1.79 M available compounds to be searched for a further 357 compounds that were added to the library. A kinase binding pharmacophore was then derived to select 174 kinase-focused fragments. Finally, an additional 61 fragments were selected to increase the number of different pharmacophores represented within the library. All of the fragments added to the library passed quality checks to ensure they were suitable for the screening protocol, with appropriate solubility, purity, chemical stability, and unambiguous NMR spectrum. The successive generations of libraries have been characterized through analysis of structural properties (molecular weight, lipophilicity, polar surface area, number of rotatable bonds, and hydrogen-bonding potential) and by analyzing their pharmacophoric complexity. These calculations have been used to compare the fragment libraries with a drug-like reference set of compounds and a set of molecules that bind to protein active sites. In addition, an analysis of the overall results of screening the library against the ATP binding site of two protein targets (HSP90 and CDK2) reveals different patterns of fragment binding, demonstrating that the approach can find selective compounds that discriminate between related binding sites. 相似文献
6.
M. J. Jackson C. Gilligan A. V. Davies R. Britton J. I. Friese L. R. Greenwood B. D. Pierson Z. S. Finch B. N. Gartman D. Dry I. May N. C. Smythe A. J. Gaunt E. R. Thomas K. E. Roberts N. K. Harward K. J. Thomas P. T. Woody P. Zhao 《Journal of Radioanalytical and Nuclear Chemistry》2018,318(1):107-115
Samarium-153 (\({}^{153}\hbox {Sm}\)) is a short-lived radionuclide that decays to stable europium-153 via beta emission, with subsequent de-excitation via gamma emission and internal conversion. Historical measurements of \({}^{153}\hbox {Sm}\) by gamma spectrometry and beta liquid scintillation counting have shown a low bias compared to beta proportional counting. In order to investigate this, four national laboratories jointly conducted an experimental inter-comparison exercise on a certified \({}^{153}\hbox {Sm}\) sample, created from neutron activation of samarium-152. Radiometric measurements were conducted using gamma spectrometry, liquid scintillation counting, gas proportional counting, and passivated implanted planar silicon detectors and compared across the four institutions against the certified value. The results from this experiment are presented together with a number of conclusions which suggest that the current published cumulative fission yield for \({}^{153}\hbox {Sm}\), as used by many laboratories, is approximately 15% high and is the likely cause of the previously observed bias. 相似文献
7.
Michael Dion Greg Eiden Orville Farmer Zach Finch Martin Liezers 《Journal of mass spectrometry : JMS》2016,51(8):591-595
A technique that uses the intrinsic mass‐based separation capability of a quadrupole mass spectrometer has been used to resolve spectral radiometric interference of two isotopes of the same element. In this work the starting sample was a mixture of 137Cs and 134Cs and was (activity) dominated by 137Cs. This methodology separated and ‘implanted’ 134Cs that was later quantified for spectral features and activity with traditional radiometric techniques. This work demonstrated a 134Cs/137Cs activity ratio enhancement of >4 orders of magnitude and complete removal of 137Cs spectral features from the implanted target mass (i.e. 134). Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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From measurement of the heat of hydrolysis, at 25°C , the enthalpy of formation of rubidium tetrafluoroiodate is derived: ΔH°f [RbIF4, cryst.]298= ?191.12±4.43 kJ mol?1. Heat capacity measurements for RbIF4 over the range 273–303 K are also reported. 相似文献
10.