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1.
Fritzsch like mass matrices with non-zero 22-elements both in U sector and D sector have been investigated in the context
of latest data regardingm
t
phys
, |V
ub|, |V
cb|, |V
td| and |V
ts|. Unlike several other phenomenological models, the present model not only accommodates the value ofm
t
phys
in the range 150–240 GeV, encompassing the CDF and D0 values, but is also able to reproduce |V
cb| ≊0.040 and |V
ub/Vcb| = 0.08±0.02 and |V
td| is predicted to lie in the range 0.005–0.014. Further, the angles of the unitarity triangle, related to the CP-violating
asymmetries, are calculated to be in the ranges −1.0⩽sin2α⩽−0.1, 0.6 ⩽sin2α⩽1.0 and 0.48⩽sin2β⩽0.56, which are in agreement
with other recent calculations. 相似文献
2.
L-shell photoelectric cross-sections have been measured at 6 keV for eight elements in the range 40⩽Z⩽53. The measurements
agree with theoretical calculations. 相似文献
3.
A study is reported of the thermoelectric and galvanomagnetic properties of n-Bi2Te3−x−y
SexSey solid solutions for 0.12⩽x⩽0.36 and 0.12⩽y⩽0.21 within the 80–300 K temperature region. The thermoelectric figure-of-merit Z has been found to correlate with the parameters of the many-valley energy-band model including anisotropic carrier scattering.
It is shown that a decrease in the constant-energy surface anisotropy and scattering anisotropy results in a growth of Z for optimum carrier concentrations in the solid solution.
Fiz. Tverd. Tela (St. Petersburg) 41, 187–192 (February 1999) 相似文献
4.
S. Baunack 《The European Physical Journal A - Hadrons and Nuclei》2007,32(4):457-461
The A4 Collaboration at the MAMI accelerator in Mainz measures the parity-violating asymmetry in the cross-section of elastic
scattering of longitudinally polarized electrons off unpolarized protons from which the contribution of strange sea quarks
to the vector form factors of the proton can be derived. Measurements at forward angles 30° ⩽ θ ⩽ 40° and two different momentum transfers Q2 of 0.23 (GeV/c)2 and 0.11 (GeV/c)2 have been performed in the past. Measurements at backward angles 140° ⩽ θ ⩽ 150° are underway for a separate determination of the strange electric and the strange magnetic form factor at Q
2 = 0.23(GeV/c)2 . 相似文献
5.
TheL shell x-ray intensity ratios have been measured for the elements Ta and W by photoionization ofL shell electrons in the photon energy region 14⩽E⩽44 keV. The experimental results are compared with those calculated at the photon energies used in the present measurements.
The measured values show fairly good agreement with the calculated values within the experimental uncertainties. 相似文献
6.
N. Türkan 《Physics of Atomic Nuclei》2007,70(9):1477-1484
We determined the most appropriate Hamiltonian that is needed for calculations of nuclei in the A ≅ 130 region from the viewpoint of the interacting boson model (IBM). Using the best-fitted values of parameters in the Hamiltonian,
we have calculated energy levels and B(E2) values for a number of transitions in some doubly even Nd nuclei of 128 ⩽ N ⩽ 140. The results were compared with the previous experimental and theoretical data, and it is observed that they are in
good agreement. The calculations have been extended to Nd isotopes for which some B(E2) values are still not known.
The text was submitted by the author in English. 相似文献
7.
Anomalous behavior of the interlayer resistance of a BSCCO-2212 crystal in a parallel magnetic field
V. N. Zavaritskii 《JETP Letters》1996,63(2):139-145
The electrical resistance across the Cu-O layers of a BSCCO-2212 single crystal is investigated in the range of angles 0°⩽φ⩽90°
between the magnetic field H⩽15 T and the ab plane. It is found that the temperature dependence R(T) at the transition into the mixed state is much sharper for φ≃0° than for 1°≲φ≲90°, where R is determined by the perpendicular component of the magnetic field and is described by the Arrhenius law R∼exp(−U/T). For H∥ ab hysteretic jumps in R(T, H), which vanish as the current increases, are observed at fields in the range 5.5⩽H⩽11 T. This effect can be attributed to
a commensurate phase transition in a lattice of Josephson vortices.
Pis’ma Zh. éksp. Teor. Fiz. 63, No. 2, 123–128 (25 January 1996) 相似文献
8.
L Satpathy 《Pramana》1989,32(4):319-330
The ground-state energy of an atomic nucleus with asymmetryβ is considered to be equivalent to the energy of a perfect sphere made up of the infinite nuclear matter of the same asymmetry
plus a residual energyη called the local energy,η represents the energy due to shell, deformation, diffuseness and exchange Coulomb effect etc. Using this picture and the
generalized Hugenholtz- Van Hove theorem of many-body theory a new mass formula has been developed. Based on this, a mass
table containing the mass excesses of 3481 nuclei in the range 18 ⩽A ⩽ 267 has been made. This mass formula is compared with other mass models. 相似文献
9.
B. Pümpin H. Keller W. Kündig I. M. Savić J. W. Schneider H. Simmler P. Zimmermann E. Kaldis S. Rusiecki C. Rossel 《Hyperfine Interactions》1991,63(1-4):25-31
A systematic μSR study of the local magnetic field distribution in a series of oxygen deficient YBa2Cu3O
x
samples with 6.5⩽x⩽7.0 is reported. Special attention was given to perform the experiments under the same conditions, so that the oxygen content
of the measured samples was the only parameter varied. The behavior of the depolarization rate σ as a function of the oxygen
contentx was found to have strong similarities with the behavior of the critical temperatureT
c
as a function ofx. In particular, two step-like increases of σ were observed abovex=6.7 and 6.9. The temperature dependence of the normalized depolarization rate σ(T)/σ(0) is well described by the two-fluid model forx⩾6.781(1) and clearly deviates from this behavior forx⩽6.704(1). Our results are compared to those obtained by other groups. 相似文献
10.
Yoshiyuki Takahashi J. N. Capdevielle A. Kawahara Y. Takao T. Sugitate O. Miyamura T. Ogata B. L. Dong Y. Takahashi O. Miyamura K. Asakimori T. H. Burnett M. L. Cherry M. J. Christl S. Dake J. H. Derrickson W. F. Fountain M. Fuki J. C. Gregory R. Holynski A. Iyono W. V. Jones A. Kawahara M. Kobayashi J. Lord K. H. Moon H. Oda T. Ogata E. D. Olson T. A. Parnell S. C. Strausz T. Sugitate Y. Takahashi Y. Takao T. Tominaga J. P. Wefel B. Wilczynska H. Wilczynski R. J. Wilkes W. Wolter H. Yokomi E. Zager 《Hyperfine Interactions》1996,103(1):99-111
The search for cosmic strangelet nuclei was carried out by two experiments with emulsion chambers. A balloon-borne JACEE emulsion
chamber was flown at 3.5 g/cm2 for 200 h in Antarctica (JACEE-10 experiment) and the Concorde flights were made by ECHOS at an atmospheric depth of 110
g/cm2 between Paris and New York. No nuclei withZ⩾30 survived after traversing 60–120 g/cm2 of the detector materials in the JACEE instruments. No evidence for a long mean free path were found in the zenith angle
distribution forZ/β⩾26 nuclei. The exposure factor used by the JACEE was 72 m2hsr. The intensity upperbounds,I⩽(2.2–9.7)×10−2/m2h sr, were obtained for strangelets having an atmospheric attenuation length of 220−50 g/cm2, which corresponds to the case for mass numberA=100–10000 andZ/β > 13. Concorde experiments (ECHOS) used both a thin and a thick emulsion chamber. The total exposure was 209 m2 h sr and no candidates with chargeZ⩾30 were found. The largest track hadZ/β=28.6±1.29 withβ ∼ 1. Nuclei observed with charge 13⩽Z⩽30 were consistent with the survival intensity of ordinary nuclei. The flux bounds from the ECHOS experiments were I⩽(2.1–5.0)
x 10−2/m2h for strangelets with mass number 100⩽A⩽1000. 相似文献
11.
Normal state electrical resistivity of the Chevrel phase compounds of the type Cu1.8Mo6S8−y
Se
y
, 0⩽y⩽8 and Cu1.8Mo6S8−y
Te
y
, 0⩽y⩽4 is analysed on the basis of the generalized diffraction model which incorporates a postulate on electron-phonon interaction,viz phonons with wavelength exceeding the electron mean-free path are ineffective electron scatterers. Fit obtained by this model
was found to be superior to other models based on the interbands-d scattering of electrons. 相似文献
12.
V. N. Berzhanskiĭ A. I. Gorbovanov S. N. Polulyakh N. V. Pronina 《Physics of the Solid State》1998,40(8):1357-1359
The effect of silicon impurities on the damping of spin-echo signals from the 57Fe nuclei of tetrahedral Fe3+ ions in epitaxial yttrium-iron-garnet films was investigated. It was found that for silicon concentrations 0.015⩽x⩽0.037 the damping of the spin echo is a two-component process, which made it possible to separate nuclei into two types,
differing by both the longitudinal and transverse magnetic relaxation times. For silicon concentrations 0.044⩽x⩽0.073 the decay of the echo can be described by one exponential and all nuclei in the sample have the same transverse relaxation
times and the same longitudinal relaxation times. The experimental results are interpreted on the basis of the supposition
that impurity “macromolecules” form around the Si4+ ions. The relaxation times of the iron nuclei in a “macromolecule” are much shorter than the relaxation times of iron nuclei
belonging to the matrix ions. The radius of a “macromolecule” is estimated on the basis of percolation theory.
Fiz. Tverd. Tela (St. Petersburg) 40, 1494–1497 (August 1998) 相似文献
13.
14.
N. N. Loshkareva Yu. P. Sukhorukov S. V. Naumov N. I. Solin I. B. Smolyak E. V. Panfilova 《JETP Letters》1998,68(1):97-100
In a study of the infrared optical absorption spectra of polycrystalline La1−x
CaxMnO3 (0.1⩽x⩽0.8), a contribution from free charge carriers is observed below the Curie temperature for compositions with x⩽0.4. The existence of this contribution for samples with a high resistivity is a direct proof of the existence of “metallic”
drops in an insulating matrix. The relative volume of the “metallic” phase is estimated.
Pis’ma Zh. éksp. Teor. Fiz. 68, No. 1, 89–92 (10 July 1998) 相似文献
15.
Feng Hu Jiamin Yang Chuanke Wang Gang Jiang Xuefeng Zhao Huaping Zang 《Central European Journal of Physics》2011,9(5):1228-1236
Relativistic configuration interaction calculations with the inclusion of the Breit interaction, quantum electrodynamics and
finite nuclear mass corrections have been carried out in the extended optimal level scheme using multiconfiguration Dirac-Fock
wavefunctions on the forbidden transition probabilities for the 2p
4 ground state configuration of the oxygen isoelectronic sequence for 8 ⩽ Z ⩽ 42. Electric quadrupole and magnetic dipole transition probabilities are reported for transitions between several of these
levels. Our results are compared with those from other theories and experiments. Our energy levels are in better agreement
with experiment than other theories. 相似文献
16.
The low-lying levels in74As have been studied by means ofγ-ray and internal conversion electron spectroscopy following the74Ge(p,n)74As reaction. New levels at 372.7, 532.8, 632.1, 731.6, 752.7, 758.3, 801.6, 902.9 and 1128.5 keV, not observed in earlier
studies, have been established.J
π assignments have been made to several low-lying levels. An earlier ambiguity regarding the identification of an isomeric
level has been clarified. The half-life of a level at 271.4 keV has been measured to be 1.0±0.1 nsec; in addition, limits
on half-lives of levels at 182.7, 277.5 and 425.4 keV have been assigned. The level structure is discussed on the basis of
available nuclear models. 相似文献
17.
A low-temperature (0.4–4.2 K) measurement of the temperature dependences of the resistivity of two series of samples, SnTe1+y
and Sn0.8Pb0.2Te1+y
solid solution, doped with 5 at.% In, is reported. The parameters of the superconducting transition, namely, the critical
temperatures T
c and the second critical magnetic field H
c2, and their dependences on tellurium excess (0⩽y⩽0.06) have been determined. The observed variation of the critical parameters with increasing tellurium excess in the samples
is associated with a change in the filling by holes of the indium-impurity resonance states.
Fiz. Tverd. Tela (St. Petersburg) 41, 2132–2134 (December 1999) 相似文献
18.
I. O. Troyanchuk L. S. Lobanovskii D. D. Khalyavin V. P. Yarunichev N. V. Pushkarev H. Szymczak 《Journal of Experimental and Theoretical Physics》1999,89(2):321-324
A study is performed of the crystalline structure, magnetization, and magnetotransport properties of the system La2/3Ba1/3(Mn1−x
Cox)O3 with perovskite structure. It is shown that cubic solid solutions exist over the entire range of cobalt concentrations 0⩽x⩽1. Compositions with x⩽0.2 are ferromagnets with maximum resistance near T
C
. Compositions with 0.2<x<0.4 manifest properties of inhomogeneous ferromagnets. Measurements of magnetic properties indicate the absence of long-range
magnetic order in compositions with 0.5⩽x⩽0.9, which are probably spin glasses. The spontaneous magnetization of cobaltate (2μ
B
per formula unit) corresponds to ferromagnetic ordering of the moments of the Co3+ and Co4+ ions found in the intermediate spin state. It is conjectured that the magnetoresistance consists of an extrinsic and an intrinsic
contribution. The first arises as a result of intergrain transport of spin-polarized charge carriers, and the second, as a
result of magnetic ordering near T
C
. The magnetoresistance is essentially independent of the spontaneous magnetization and decreases abruptly as the cobalt concentration
is increased with a corresponding transition from long-range to short-range magnetic order.
Zh. éksp. Teor. Fiz. 116, 604–610 (August 1999) 相似文献
19.
YingTang Zhang ChunChang Wang WeiBin Liu Zhong Wang HuiBin Lu ZiYu Chen 《中国科学G辑(英文版)》2009,52(12):1893-1897
A series of samples of La1−x
Tb
x
MnO3 (0⩽x⩽0.15) are prepared. The static and dynamic magnetizations of La1−x
Tb
x
MnO3 have been investigated. The results indicate that the spins with the short-range order are frozen into random direction at
low enough temperatures which leads to the samples exhibiting the spin-glass like behavior. It is considered that the spin-glass
like behavior originates from the competition between ferromagnetic double exchange among Mn3+ and Mn2+ and antiferromagnetic superexchange among Mn3+ and Mn3+, as well as Tb3+ and Tb3+. 相似文献
20.
A. M. Ermolaev 《Hyperfine Interactions》1993,76(1):335-341
The theoretical ratioR
i of antiproton/proton cross sections for nondissociative ionization of hydrogen molecule has been obtained as a function of
the impact energyE in the range 30⩽E⩽2500 KeV lab. The required cross sections were computed in the close-coupling formulation of the semiclassical impact parameter
theory using a simple one-active electron model for the molecular target. The ratioR
i is important for the analysis of the recent experimental data of Andersen et al. on antiproton scattering and the understanding
of the collisional mechanisms in the KeV range. 相似文献