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61.
The time-differential perturbed angular correlation (TDPAC) experiments involving the 133–482 keV γ-γ cascade in181Ta have been performed in the presence of an external magnetic field along the quantization axis to measure the hyperfine magnetic field experienced by181Ta nuclei at the Hf site in the pseudobinary compounds HfFe2?xSix with x=0.1 and x=0.3. The hyperfine magnetic fields measured at 298 K are Hhf=133.1±12.0 kG in the cubic (C15) Laves phase compound HfFe1.9Si0.1 and Hhf=76.8±7.0 kG in the hexagonal (C14) Laves phase compound HfFe1.7Si0.3. The measured hyperfine fields are discussed within the framework of the Campbell-Blandin model. 相似文献
62.
M. I. El-Zaiki W. Z. Megalaa H. R. Saad A. A. Youssef 《Zeitschrift für Physik A Hadrons and Nuclei》1970,234(5):398-404
Angular distributions of gamma rays following the inelastic scattering of protons from Mn55 have been measured at proton energies below 2.50 MeV. The mixture multipole orders for the transition 983→126 keV and 1,530→0 in Mn55 have been obtained. 相似文献
63.
Adams Peter Bryant Darryn El-Zanati Saad I. Gavlas Heather 《Graphs and Combinatorics》2003,19(3):289-296
In this paper, we show that K10n can be factored into C5-factors and 1-factors for all non-negative integers and satisfying 2+=10n–1.Research partially supported by an NSF-AWM Mentoring Travel Grant 相似文献
64.
The response characteristics of the solid state cyanide ion selective electrode towards some benzylnitriles are investigated. In 10M KOH solution, the electrode exhibits nearly Nernstian response over the concentration range of 10–2 to 10–4
M of various substituted benzylnitriles with an anionic slope of 53–59 mV/concentration decade. The response time varies from 10 to 20 min depending on both the nature of the substituent group and the concentration of the nitrile compound. Direct potentiometric measurement of some nitrile compounds at the concentration level of 0.01 to 1 mg/ml shows an average recovery of 98.2% and a mean standard deviation of 2.3%. Many nitrogen functional groups do not interfere. 相似文献
65.
Cu-doped borate glass co-doped with SnO2 nanoparticles is fabricated by melt quenching. The structure and morphology of the samples are examined by X-ray diffraction and field emission scanning electron microscopy. Up-conversion enhancement is observed in the photoluminescence (PL) and thermolumines- cence (TL) intensities of the glass. PL emission spectra are identified in the blue and green regions, and a fourfold increase in emission intensity may be observed in the presence of embedded SnO2 nanoparticles. The glow curve is recorded at 215℃, and fourfold increases in TL intensity are obtained by addition of 0.1 mol% SnO2 nanoparticles to the glass. Higher TL responses of the samples are observed in the energy range of 15-100 KeV. At energy levels greater than -0.1 MeV, however, flat responses are obtained. The activation energy and frequency factor of the second-order kinetic reaction are calculated by the peak shape method. 相似文献
66.
67.
Darryn E. Bryant Saad El-Zanati Charles Vanden Eynden Dean G. Hoffman 《Graphs and Combinatorics》2001,17(1):55-59
Let S
k
denote the complete bipartite graph K
1,
k
and let Q
n
denote the n-cube. We prove that the obvious necessary conditions for the existence of an S
k
-decomposition of Q
n
are sufficient.
Received: July 21, 1999 Final version received: May 16, 2000 相似文献
68.
Ali Saad Manef Abderrabba Mohamed M. Chehimi 《Surface and interface analysis : SIA》2017,49(4):340-344
Mesoporous silica SBA‐15 was synthesized and silanized with azidopropyl triethoxysilane in order to design a clickable material. Fourier transform infrared analysis permitted to prove the attachment of the azidopropylene groups to SBA‐15 resulting in the reactive and functional material N3‐SBA‐15. X‐ray photoelectron spectroscopy was used to determine the surface composition of SBA‐15. However, we unexpectedly found that the surface bound azido groups undergo X‐ray induced decomposition during the X‐ray photoelectron spectroscopy analysis resulting in the formation of nitrenes. These are very reactive groups able to intercalate C―C and C―H bonds of the propylene chains as judged from the N1s peak shape. Possible mechanisms of intercalation are suggested. C1s and N1s peaks were recorded at different exposure time. N/C, N+/N and N+/C undergo exponential decay. N+/N reaches the value of zero in less than 80 min of exposure to the X‐ray source. The N+/C decay plot was fitted with first‐order kinetics, and the decomposition kinetic constant (kdec) was found to equal to 516.4 s?1. This is a fast X‐ray induced degradation which must be considered with care when examining clickable materials with surface bound alkyl azido groups. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
69.
Single crystals of the title compound are obtained from a melt of U3O8, MoO3, and excess Cs2CO3 (Pt crucible, 950 °C, 12 h, cooling rate 5 °C/h). 相似文献
70.
Three sorbent materials (A18C6-MS, DA18C6-MS and AB18C6-MS) based on the crown ether ligands, 1-aza-18-crown-6, 1,4,10,13-tetraoxa-7,16-diazacyclo octadecane and 4′-aminobenzo-18-crown-6, respectively, were prepared by the chemical immobilization of the ligand onto mesoporous silica support. The sorbents were characterized by FT-IR, scanning electron microscopy-energy dispersive X-ray microanalysis, elemental analysis and nitrogen adsorption-desorption test. The applicability of the sorbents for the extraction of biogenic amines by the batch sorption method was extensively studied and evaluated as a function of pH, biogenic amines concentration, contact time and reusability. Under the optimized conditions, all the sorbents exhibited highest selectivity toward spermidine (SPD) compared to other biogenic amines (tryptamine, putrescine, histamine and tyramine). Among the sorbents, AB18C6-MS offer the highest capacity and best selectivity towards SPD in the presence of other biogenic amines. The AB18C6-MS sorbent can be repeatedly used three times as there was no significant degradation in the extraction of the biogenic amines (%E > 85). The optimized procedure was successfully applied for the separation of SPD in food samples prior to the reversed-phase high performance liquid chromatography separation. 相似文献