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891.
Gaurav Shukla 《Applied Physics A: Materials Science & Processing》2009,97(1):115-118
In this paper, we report on pulsed laser deposition of n-type Cu-doped ZnO thin films on c-plane sapphire substrates at 700°C.
XRD and HRTEM were employed to study the epitaxial growth relationship between the Zn1−x
Cu
x
O film and sapphire substrate. Absorption measurements showed excitonic nature of the thin films and a decrease in the bandgap
energy with increased Cu concentration was observed. Such as-deposited films showed room temperature ferromagnetism with Curie
temperature (T
c
) at around 320 K. The moment per Cu atom decreases as the Cu concentration increases. The largest magnetic moment about 0.81μ
B
/Cu atom was observed for Zn0.95Cu0.05O thin films. The presence of any magnetic second phase was ruled out and the ferromagnetism was attributed to Cu ions substituted
directly into the ZnO lattice. 相似文献
892.
Since the introduction of binomial state as an intermediate state, different intermediate states have been proposed. Different nonclassical effects have also been reported in these intermediate states. But till now higher order antibunching is predicted in only one type of intermediate state, which is known as shadowed negative binomial state. Recently we have shown that the higher order antibunching is not a rare phenomenon [P. Gupta, P. Pandey, A. Pathak, J. Phys. B 39 (2006) 1137]. To establish our earlier claim further, here we have shown that the higher order antibunching can be seen in different intermediate states, such as binomial state, reciprocal binomial state, hypergeometric state, generalized binomial state, negative binomial state and photon added coherent state. We have studied the possibility of observing the higher order subpoissonian photon statistics in different limits of intermediate states. The effects of different control parameters on the depth of non classicality have also been studied in this connection and it has been shown that the depth of nonclassicality can be tuned by controlling various physical parameters. 相似文献
893.
P. U. Sharma M. K. Roy Ravi Kumar H. C. Verma H. H. Joshi K. B. Modi 《Hyperfine Interactions》2008,187(1-3):117-124
The consequences of swift heavy ion (SHI) irradiation (Li3?+?, 50 MeV, fluence =?5 × 1013 ions/cm2) on the structural and microscopic magnetic properties of Y3?+?-substituted yttrium iron garnet (Y3?+?x Fe5???x O12, x = 0.0, 0.2 and 0.4) have been studied at 300 K. It is found that an additional YFeO3-phase observed along with bcc garnet phase, is completely removed for x = 0.2 composition while its percentage formation considerably reduces for x = 0.4 composition after irradiation. Similar effect has been observed for specimens sintered at 1,500°C. The SHI-induced ion beam mixing has been revealed through X-ray diffraction and Mössbauer spectroscopy. 相似文献
894.
A method based on wavelet transform is developed to characterize variations at multiple scales in non-stationary time series.
We consider two different financial time series, S&P CNX Nifty closing index of the National Stock Exchange (India) and Dow
Jones industrial average closing values. These time series are chosen since they are known to comprise of stochastic fluctuations
as well as cyclic variations at different scales. The wavelet transform isolates cyclic variations at higher scales when random
fluctuations are averaged out; this corroborates correlated behaviour observed earlier in financial time series through random
matrix studies. Analysis is carried out through Haar, Daubechies-4 and continuous Morlet wavelets for studying the character
of fluctuations at different scales and show that cyclic variations emerge at intermediate time scales. It is found that Daubechies
family of wavelets can be effectively used to capture cyclic variations since these are local in nature. To get an insight
into the occurrence of cyclic variations, we then proceed to model these wavelet coefficients using genetic programming (GP)
approach and using the standard embedding technique in the reconstructed phase space. It is found that the standard methods
(GP as well as artificial neural networks) fail to model these variations because of poor convergence. A novel interpolation
approach is developed that overcomes this difficulty. The dynamical model equations have, primarily, linear terms with additive
Padé-type terms. It is seen that the emergence of cyclic variations is due to an interplay of a few important terms in the
model. Very interestingly GP model captures smooth variations as well as bursty behaviour quite nicely.
相似文献
895.
The yrast bands of even-even selenium isotopes with A = 68–78 are studied in the framework of projected shell model, by employing quadrupole plus monopole and quadrupole pairing
force in the Hamiltonian. The oblate and prolate structures of the bands have been investigated. The yrast energies, backbending
plots and reduced E2 transition probabilities and g-factors are calculated and compared with the experimental data. The calculated results are in reasonably good agreement with
the experiments.
相似文献
896.
B. G. Verma 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1970,21(1):119-124
Zusammenfassung Die Ähnlichkeitslösung von Lin für starke zylindrische Stösse wird verallgemeinert für den Fall, dass der Stoss in einem Plasma und in einem Magnetfeld parallel zur Zylinderachse sich ausbreitet. 相似文献
897.
Satya Dev Verma 《Proceedings Mathematical Sciences》1967,66(3):125-143
Calculations are carried out to determine the flux and energy spectra of secondary electrons which are produced by the cosmic radiation in the upper layers of the atmosphere. The calculations are valid to an atmospheric depth of about 10 g./cm.2 Electron spectra are presented for different depths and locations where measurements of the electron flux have been carried out: Ft. Churchill, Manitoba; Sioux Falls, South Dakota; Palestine, Texas; and Hyderabad, India. The calculations are compared with observed electron fluxes during the ascents of balloon flights. 相似文献
898.
899.
900.
Cottrell’s binding energy between a dislocation and vacancy and concentration of vacancies has been calculated using ultrasonic
attenuation measurements in single crystals of pure tin at 300K for frequencies varying from 3 to 50 MHz and at different
dislocation densities. 相似文献