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Films of nonuniform Cu100−xCox alloys with x = 6, 11, 20, and 35 at. %, obtained by electrolytic deposition, are investigated using quantum magnetometry
in fields of up to 5.5 T and temperatures of 2–300 K. In all the compositions a characteristic feature is the deviation from
pure superparamagnetic behavior, which increases as the annealing of the films and their cobalt content increase.
Institute of Solid State and Semiconductor Physics. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3,
pp. 60–62, March, 1998. 相似文献
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McSparron H Blythe MJ Zygouri C Doytchinova IA Flower DR 《Journal of chemical information and computer sciences》2003,43(4):1276-1287
JenPep is a relational database containing a compendium of thermodynamic binding data for the interaction of peptides with a range of important immunological molecules: the major histocompatibility complex, TAP transporter, and T cell receptor. The database also includes annotated lists of B cell and T cell epitopes. Version 2.0 of the database is implemented in a bespoke postgreSQL database system and is fully searchable online via a perl/HTML interface (URL: http://www.jenner.ac.uk/JenPep). 相似文献
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Dielectric relaxation occurring in single- and polycrystalline BaTiO3, following different polarization treatments of the specimens has been investigated in the temperature range 10 K<T<450 K. The observed relaxation phenomena are discussed in terms of polarization induced growth of extra-domains which, via corresponding enhancement of the total domain wall area, may account for the time dependence of the dielectric constant. On the basis of this relaxation model the activation parameters of the different processes are determined and discussed in terms of variations of the wall mobility within the different crystallographic phases occurring in BaTiO3. 相似文献
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An analytical method that enables detection and quantification of bromophenols (BPs) at taste threshold concentrations (2,6-DBP: 0.5 ng/L) was developed. This method involves conversion of the BPs to their acetates, followed by isolation of the acetates by a modified purge-and-trap procedure, and analysis by gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode. Bromophenyl acetates were synthesized so that each of the two steps in the method could be developed and optimised in isolation to the other. Deuterated BPs (phenol-d5, 2-BP-d4, 4-BP-d2, 2,6-DBP-d3, 2,4-DBP-d3 and 2,4,6-TBP-d2) were synthesized to enable quantification of analytes using the deuterated analogues of analytes as internal standards. This method allowed quantification of BPs at concentrations ranging from the detection limits (3 ng/L for phenol and 0.1-0.5 ng/L for each of the BPs) to 1000 ng/L for each analyte, with repeatabilities of < or =14% (RSD) for concentrations of 1 ng/L and < or =9% (RSD) for concentrations of 10-1000 ng/L, with recoveries ranging from 91 to 97%. 相似文献
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Abstract Magnetic after-effect measurements have been made in the temperature range 4.2–300 K on both polycrystalline and single-crystal cobalt samples following irradiation with 3 MeV electrons. The temperature of irradiation was 30 K and the dose 1023 m?2. All stable relaxation peaks have been analysed quantitatively and their correlated annealing behaviour investigated. The results are discussed in terms of both intrinsic interstitial clusters and also the interaction of intrinsic interstitials with interstitial carbon and substitutional impurity atoms. 相似文献
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The variation of the dielectric permittivity and loss factor with frequency and temperature has been measured for two polyethers with polar side groups, polyepichlorhydrin and polyepibromhydrin. Both polymers showed two distinct relaxation processes. The high-temperature relaxations correlate with the glass-to-rubber transition temperatures in accord with the WLF equation. For the low-temperature relaxations, attributed to rotational motion of the side groups, the activation energy for the bulkier—CH2Br case is smaller than—CH2Cl. This effect and the extreme broadness of these relaxations are explained by considering dipole-dipole interactions. Calculations for selected model conformations show that intramolecular dipole-dipole interactions are weak, but that inter-molecular dipole-dipole interactions can account for the observed order of activation energies. 相似文献
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P. J. Blythe A. Klein J. A. Phillips E. D. Sudol M. S. El-Aasser 《Journal of polymer science. Part A, Polymer chemistry》1999,37(23):4449-4457
The Mettler RC1 calorimeter was used to measure the rate of polymerization of conventional emulsion, homogenized emulsion, and miniemulsion polymerizations of styrene initiated with 2,2′-azobis(2-methylbutyronitrile). It was noted that the rate of polymerization significantly increased as the surface area of the monomer droplets increased. This was taken as strong evidence that in the miniemulsion and homogenized emulsion polymerizations, the fraction of the initiator soluble in the oil phase was responsible for single radical generation. The partitioning of AMBN at 70 °C was measured by high-pressure liquid chromatography to be 134 parts in the oil : 1 part in the water. Predissolving polystyrene in the miniemulsion prior to homogenization resulted in an enhancement in the rate of polymerization, although to a lesser extent than what has been previously noted for parallel miniemulsion polymerizations initiated with potassium persulfate. It was also noted that the method of addition of the oil-soluble initiator (either predissolved in the monomer prior to homogenization or dissolved in a small separate phase of monomer and added directly to the reactor) has a measurable effect on the kinetics in the miniemulsion polymerization of styrene. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4449–4457, 1999 相似文献