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排序方式: 共有288条查询结果,搜索用时 31 毫秒
31.
A. A. Blinkin V. V. Derevyanko T. V. Sukhareva V. L. Uvarov V. A. Finkel Yu. N. Shakhov I. N. Shlyakhov 《Physics of the Solid State》2011,53(2):245-255
This paper reports on the results of investigations of the influence of irradiation of the two-band BCS superconductor MgB2 by electrons with an average energy $
\bar {\rm E}
$
\bar {\rm E}
∼ 10 MeV at high doses (0 ≤ ϕt ≤ ∼2.5 × 1018 cm−2) on the temperature and width of the transition to the superconducting state, the temperature dependence of the electrical
resistivity in the normal state, the crystal lattice parameters, and the diffraction line intensity. An increase in the electron
irradiation dose ϕt leads to the following effects: a decrease in the critical temperature T
c
; an increase in the width of the superconducting transition ΔT
c
; and a decrease in the “residual electrical resistivity” ρ273 K/ρ40 K, in the parameters a and c of the hexagonal crystal lattice, and in the ratio between the diffraction line intensities I
110/I
100. From analyzing the results obtained, it has been established that the main type of radiation damages under irradiation of
the BCS superconductor MgB2 by high-energy electrons is the formation of vacancies in the B sublattice, which leads to a narrowing of the large band
gap Δσ on the Fermi surface. 相似文献
32.
33.
Liondas CA; Chrissoulidis DP 《The Quarterly Journal of Mechanics and Applied Mathematics》2007,60(3):275-287
This paper is intended to clarify a misunderstanding concerningthe source singularity of the electric Green's tensor for aperfectly conducting semi-infinite cone of circular cross-section.Tai's series expansion of the Green's tensor is known to lacka singular term at the source region. Jones has reconstructedthe solution to this problem and has pointed out the differencebetween his result and that of Tai. The aim of our paper isto demonstrate that, although Jones's closed-form solution iscorrect, there is a mistake in his comparison with Tai's seriessolution. We conclude that one of the two additional singularterms that Jones claims as missing from Tai's formula must beomitted. Besides, we compare Jones's closed-form solution withSmyshlyaev's solution to the very same problem. We concludethat the magnetic field expressions given by Jones and Smyshlyaevcoincide, but a singular term is missing from Smyshlyaev's expressionfor the electric field. 相似文献
34.
F. Botterweck M. M. Chapkin M. Charlet P. V. Chliapnikov A. De Roeck E. A. De Wolf K. Dziunikowska A. Eskreys Z. C. Garutchava G. R. Gulkanyan T. Haupt L. P. Kishinevskaya W. Kittel I. V. Nikolaenko K. Olkiewicz V. M. Ronjin L. N. Smirnova O. G. Tchikilev L. A. Tikhonova V. A. Uvarov F. Verbeure R. Wischnewski S. A. Zotkin 《Zeitschrift fur Physik C Particles and Fields》1991,51(4):541-548
Inclusive production of direct soft photons is studied inK + p andK + π interactions at 250 GeV/c. Total cross sections, Feynman-x and transverse momentum distributions of direct γ's are presented. The measured cross sections are several times larger than expected from QED inner bremsstrahlung, indicating the presence of an anomalous soft photon source. The model of Lichard and Van Hove, based on the “cold quark-gluon plasma” picture, agrees with the data. 相似文献
35.
Goodman TNT; Micchelli CA; Rodriguez G; Seatzu S 《IMA Journal of Numerical Analysis》1998,18(3):331-354
It is shown that, under certain conditions, orthonormalizingthe positive integer shifts of an exponentially decaying functionon the half line by the Gram-Schmidt process leads to a limitingprofile given by orthonormalizing all their integer shifts onthe whole line. These results derive from properties of Choleskyfactorization of bi-infinite and semi-infinite matrices. Anexample is provided by the negative exponential function andconjectures are given, supported by numerical evidence, forthe Gaussian and Lorentz function. 相似文献
36.
I. V. Ajinenko Yu. A. Belokopytoy H. Bialkowska H. Boettcher F. Bottorweck P. V. Chliapnikov F. Crijns A. de Roeck E. A. de Wolf K. Dziunikowska A. M. F. Endler A. Eskreys Z. C. Garutchava Y. Golubkov H. Graessler G. R. Gulkanyan P. van Hal R. Sh. Hakobyan T. Haupt W. Kittel D. Kisielewska B. B. Levchenko F. Meijers A. B. Micha?owska Th. Naumann V. I. Nikolaenko K. Olkiewicz B. Pawlik L. P. Petrovikh R. P?ll?nen V. M. Ronjin A. M. Rybin H. M. T. Saarikko W. Schmitz L. Scholten L. N. Smirnova O. G. Tchikilev A. G. Tomaradze V. A. Uvarov F. Verbeure R. Wischnewski EHS-NA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1989,42(3):377-385
Multiplicity distributions, observed inK + interactions with Al and Au nuclei at 250 GeV/c incident momentum are presented. They are analyzed in the framework of multiple collisions of the incident particle inside a nucleus. The probability distribution of the number of grey tracks is well described by the model of Andersson et al., if a negative binomial distribution is assumed for the distribution of the number of grey protons produced per elementary collision instead of the usual geometrical distribution. The analysis of the average and dispersion of the charge multiplicity distribution supports the validity of the multiple collision model, including results on correlations between forward and backward multiplicities. 相似文献
37.
E. A. Koteneva N. N. Pestereva I. E. Animitsa N. F. Uvarov 《Russian Journal of Electrochemistry》2017,53(7):739-743
Metal molybdates MMoO4 (M = Ca, Sr) and their composites with vanadium oxide V2O5 were synthesized. An X-ray diffraction analysis confirmed that the obtained molybdates were single-phase, and the heterogeneous systems were two-phase. The temperature dependences of the total conductivity of the composites were studied. The ion transport numbers in the {CaMoO4 · xV2O5} composites (x = 1–30 mol %) were studied by the EMF method. The conductivity of the composites at x ≤ 5 mol % was shown to be ionic. The conductivity of the composites was described using the mixing equation. 相似文献
38.
D. B. Vasil’chenko S. V. Korenev I. A. Baidina V. A. Drebushchak N. K. Moroz S. G. Kozlova A. S. Ulikhin N. F. Uvarov 《Russian Journal of Electrochemistry》2011,47(5):631-636
The method of deposition from solutions was used to synthesize [RhL
4Cl2]HSO4 · nH2SO4 · mH2O complex salts (L = Py, γ-picoline), n ≈ 0.5−0.6, m ≈ 5−6. According to the data of X-ray phase analysis, the crystal structure of these salts is formed by layers of cations
separated by layers consisting of anions molecules of sulfuric acid and water connected through a system of hydrogen bonds.
Calorimetric methods were used to study phase transitions and the range of thermal stability of salts. The method of 1H NMR spectroscopy discovered that protons within the {HSO4− · nH2SO4 · mH2O} subsystem featured enhanced conductivity. Conductivity studies showed that trans-[RhL
4Cl2]HSO4 · nH2SO4 · mH2O samples had high proton conductivity. 相似文献
39.
Yu. T. Pavlyukhin S. A. Petrov K. B. Gerasimov N. F. Uvarov 《Russian Journal of Electrochemistry》2011,47(6):657-662
High-temperature proton-conducting Ba2SnY1 ? x Fe x O6 ? δ oxides are studied by Mössbauer spectroscopy on 119Sn and 57Fe isotopes. For the perovskite structure, the possible states of anionic vacancies are discussed as a function of the nature of the nearest small cations. It is concluded that the energy of formation of a cation-vacancy-cation defect depends on the overall concentration of vacancies in the compound. As the result, with the increase in the water content in the Ba2SnYO6 ? δ compound, the equilibrium shifts to the tin-vacancy-tin state. 相似文献
40.
Ionic conductivity of high-temperature phases of alkaline metal perchlorates is studied. It is found that the conductivity passes through a minimum with increasing radius of cation, and KClO4 exhibits the lowest conductivity. This is explained by a decrease in the relative size of conduction channel, which hampers the cation transfer, and an increase in the relative free volume. The free-volume increase promotes the perchlorate anion reorientation and reduces the activation energy for ion transfer by the “paddle-wheel” mechanism; as a result, the conductivity increases. 相似文献