共查询到20条相似文献,搜索用时 15 毫秒
1.
Z. H. Cao P. Liu X. K. Meng S. C. Tang H. M. Lu 《Applied Physics A: Materials Science & Processing》2009,94(2):393-398
The crystallization of amorphous Ge films has been studied as a function of annealing temperature between 400 and 700°C by
in situ transmission electron microscopy (TEM). It is found that crystallization does not occur until the annealing temperature
reaches 650°C, which is nearly 250°C higher than the crystallization temperature in previous reports. The high crystallization
temperature and average crystal size obtained by in situ TEM are in agreement with those from Raman spectroscopy and X-ray
diffraction measurement. The kinetics analysis indicates that homogeneous nucleation is the dominant crystallization mode
and the activation energy is up to about 3.1 eV. 相似文献
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3.
Ratul Chowdhury Ritabrata Biswas Nairwita Mazumder Subenoy Chakraborty 《International Journal of Theoretical Physics》2011,50(5):1628-1642
This paper deals in the thermodynamic properties of Einstein-Gauss-Bonnet and Einstein-Yang-Mills-Gauss-Bonnet black holes.
It exhibits the various stable and unstable phases of the black holes in these two modified gravity theories. In the first
section, that reveals the various aspects of Einstein-Gauss-Bonnet black holes, we chose to study the changes in the Hawking
Temperature with variations in the radius of event horizon (r) and charge (Q); and tried to justify them physically. Secondly in case of Einstein-Yang-Mills-Gauss-Bonnet black holes, we have attempted
to compare the changes in the various thermodynamic parameters with varying r and Q; with the Einstein-Gauss-Bonnet black holes at a macroscopic level. Here we have considered the Yang Mills tensor, electromagnetic
Lagrangian added to the action integrand. Again this very work deals in drawing out the similarities between these two types
of black holes, thereby throwing some light on the aspect of black hole stability. Later we have also introspected the effects
of the Gauss-Bonnet coupling parameter α, whose function (6αr), is added as a correction term to the black hole entropy. We have especially focused on what changes does it have upon the
nature of the plots as to whether it enhances or reduces the effect of Q on the behavior of the curves. Finally this paper has also kept an eye at estimating the stability domains of the black holes
described in these two gravity theories. 相似文献
4.
《Nuclear Physics A》1987,462(4):791-802
We investigate suggestions that quark matter with strangeness per baryon of order unity may be stable. We model this matter at nuclear matter densities as a gas of close packed Λ-particles. From the known mass of the Λ-particle we obtain an estimate of the energy and chemical potential of strange matter at nuclear densities. These are sufficiently high to preclude any phase transition from neutron matter to strange matter in the region near nucleon matter density. Including effects from gluon exchange phenomenologically, we investigate higher densities, consistently making approximations which underestimate the density of transition. In this way we find a transition density ρtr≳7ρ0, where ρ0 is nuclear matter density is not far from the maximum density in the center of the most massive neutron stars that can be constructed. Since we have underestimated ρtr and still find it to be ∼7ρ0, we do not believe that the transition from neutron to quark matter is likely in neutron stars. Moreover, measured masses of observed neutron stars are ≅1.4 M⊙, where M⊙ is the solar mass. For such masses, the central (maximum) density is ρc<5ρ0. Transition to quark matter is certainly excluded for these densities. 相似文献
5.
James F. Woodward 《Foundations of Physics》1992,22(2):187-203
It is noted that Popper separates the creation of concepts, conjectures, hypotheses and theories—the context of invention—from the testing thereof—the context of justification—arguing that only the latter is susceptible of rigorous logical analysis. Efforts on the part of others to shift or eradicate the demarcation established by this distinction are discussed and the relationship of these considerations to the claims of strong artificial intelligence is pointed out. It is argued that the mode of education of scientists, as well as reports of celebrated scientists, support Popper's judgement in this matter. An historical episode from Faraday's later career is used to illustrate the historiographical strength of Lakatos' methodology of research programs. 相似文献
6.
Jun Ren 《International Journal of Theoretical Physics》2009,48(7):2088-2097
In this paper, we study the thermal properties of the inner horizon of a Kerr-Newman black hole. By adopting Damour-Ruffini
method and the thin film model which is developed on the base of brick wall model suggested by ’t Hooft, we calculate the
temperature and the entropy of the inner horizon of a Kerr-Newman black hole. We conclude that the temperature of inner horizon
is positive and the entropy of the inner horizon is proportional to the area of the inner horizon. The cut-off factor is same
as it in calculation of the entropy of the outer horizon, 90β. In addition, we write the integral and differential Bekenstein-Smarr formula as the parameters of the inner horizon. Then,
we discuss that if the contribution of the inner horizon is taken into account to the total entropy of the black hole, the
Nernst theorem can be satisfied. At last, We calculate the tunneling rate of the outer horizon Γ+ and the inner horizon Γ−. The total tunneling rate Γ should be the product of the rates of the outer and inner horizon, Γ=Γ+⋅Γ−. We find that the total tunneling rate is in agreement with the Parikh’s standard result, Γ→exp (ΔS
BH
), and there is no information loss. 相似文献
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8.
Shanhong Wan Liping Wang Qunji Xue 《Applied Physics A: Materials Science & Processing》2011,102(3):753-760
Sulfur-doped DLC nanocomposite films have been successfully deposited by the electrochemical method using the mixture of methanol
and thiofuran as the precursor at ambient atmospheric pressure. In contrast to DLC film, the effects of sulfur incorporation
on the microstructural transformation and properties of sulfur-doped DLC nanocomposite films were investigated in detail in
terms of atomic force microscopy, X-ray photoelectron spectroscopy, Raman spectrum and photoluminescence and magnetic tests.
The experimental results showed that the unexpected organic molecular structure was formed like sulfone or thiols in sulfur-doped
DLC nanocomposite films, and the concentration of sulfur in films was readily manipulated by the volume ratio of thiofuran
to methanol. Meanwhile, the sp3-hybridized carbon content gradually decreased in films as the volume of thiofuran increased. Furthermore, sulfur-doped DLC
nanocomposite films showed the monochromatic photoluminescence performance with a wide band centered at 510 nm, which could
be attributed to carrier localization within an increasing sp2 clusters and the defects along with the sulfur doping. Particularly, ferro-like magnetic performance of sulfur-doped DLC
nanocomposite film might originate from the magnetic moment of localized sp2 clusters with different charged carriers near the Fermi level after sulfur incorporation. 相似文献
9.
P. Narayana Swamy 《International Journal of Theoretical Physics》2009,48(8):2432-2440
Many of us are familiar with Feynman’s “proof” of 1948, as revealed by Dyson, which demonstrates that Maxwell equations of
electromagnetism are a consequence of Newton’s laws of motion of classical mechanics and the commutation relations of coordinate
and momentum of quantum mechanics. It was Feynman’s purpose to explore the universality of dynamics of particles while making
the fewest assumptions. We re-examine this formulation in the context of quantum gravity and show how Feynman’s derivation
can be extended to include quantum gravity. 相似文献
10.
Xue-Xiang Xu 《International Journal of Theoretical Physics》2011,50(5):1643-1655
In this work, we find that a set of energy eigenstates of the Hamiltonian of two coupled oscillators can be classified as
the atomic coherent state in the Schwinger Bosonic realization. The statistical properties of these states are also discussed
by analytically calculating their Wigner function, Husimi function and tomogram. 相似文献
11.
Viqar Husain 《General Relativity and Gravitation》1998,30(10):1439-1443
Initial data for general relativity may be such that there are trapped surfaces on a spatial initial data surface. Penrose has proposed that if the cosmic censorship hypothesis is true, the ADM mass M of asymptotically flat initial data and the area A of the outermost apparent horizon surface should satisfy the inequality A 16M2. Initial data which does not satisfy this inequality may be viewed as providing a counterexample of the cosmic censorship conjecture. We describe initial data that appears to violate this inequality. 相似文献
12.
Are citations of scientific papers a case of nonextensivity? 总被引:1,自引:0,他引:1
C. Tsallis M.P. de Albuquerque 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,13(4):777-780
The distribution N(x) of citations of scientific papers has recently been illustrated (on ISI and PRE data sets) and analyzed by Redner (Eur.
Phys. J. B 4, 131 (1998)). To fit the data, a stretched exponential () has been used with only partial success. The success is not complete because the data exhibit, for large citation count
x, a power law (roughly for the ISI data), which, clearly, the stretched exponential does not reproduce. This fact is then attributed to a possibly
different nature of rarely cited and largely cited papers. We show here that, within a nonextensive thermostatistical formalism,
the same data can be quite satisfactorily fitted with a single curve (namely, [0pt] for the available values of x. This is consistent with the connection recently established by Denisov (Phys. Lett. A 235, 447 (1997)) between this nonextensive formalism and the Zipf-Mandelbrot law. What the present analysis ultimately suggests
is that, in contrast to Redner's conclusion, the phenomenon might essentially be one and the same along the entire range of the citation number x.
Received 13 April 1999 相似文献
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14.
Writambhara Chakraborty Ujjal Debnath 《International Journal of Theoretical Physics》2009,48(1):232-247
In this work we have studied the possibility of obtaining cosmic acceleration in Brans-Dicke theory with varying or constant
ω (Brans-Dicke parameter) and with or without self-interacting potential, the background fluid being barotropic fluid or Generalized
Chaplygin Gas. Here we take the power law form of the scale factor and the scalar field. We show that accelerated expansion
can also be achieved for high values of ω for closed Universe. 相似文献
15.
Ning Guo Jinquan Wei Qinke Shu Yi Jia Zhen Li Kun Zhang Hongwei Zhu Kunlin Wang Shuang Song Ying Xu Dehai Wu 《Applied Physics A: Materials Science & Processing》2011,102(1):109-114
A?novel method of combining photolithography, wet chemical etching and oxidation process was proposed to fabricate large area of silicon microwire (SiMW) arrays. The dimensions of the SiMWs can be easily controlled by photomask and etching conditions. Solar cells based on the heterojunction between SiMW and double-walled carbon nanotubes (DWNTs) were constructed. The initial test on the DWNT/SiMW shows efficiency (??) of?0.59%. By adding a few drops of HBr/B2 electrolyte, the efficiency was improved to 1.96% with J sc=19.2?mA/cm2 and V oc=0.35?V, FF=29.2%, showing the potential of SiMWs in photovoltaic applications. 相似文献
16.
Saibal Ray Maxim Khlopov Partha Pratim Ghosh Utpal Mukhopadhyay 《International Journal of Theoretical Physics》2011,50(3):939-951
Among various phenomenological Λ models, a time-dependent model [(L)\dot] ~ H3\dot{\Lambda}\sim H^{3} is selected here to investigate the Λ-CDM cosmology. The model can follow from dynamics, underlying the origin of Λ. Using
this model the expressions for the time-dependent equation of state parameter ω and other physical parameters are derived. It is shown that in H
3 model accelerated expansion of the Universe takes place at negative energy density, but with a positive pressure. It has
also been possible to obtain the change of sign of the deceleration parameter q during cosmic evolution. 相似文献
17.
Mariano Anabitarte Mauricio Bellini 《The European Physical Journal C - Particles and Fields》2009,60(2):297-301
We revisit an extension of the well-known formalism for gauge-invariant scalar metric fluctuations to study the spectra for
both the inflaton and gauge-invariant (scalar) metric fluctuations in the framework of a single-field inflationary model,
in which the quasi-exponential expansion is driven by an inflaton which is minimally coupled to gravity. The proposal here
examined is valid also for fluctuations with large amplitudes, but for cosmological scales, where vector and tensor perturbations
can be neglected and the fluid is irrotacional. 相似文献
18.
Takatsu H Kadowaki H Sato TJ Lynn JW Tabata Y Yamazaki T Matsuhira K 《J Phys Condens Matter》2012,24(5):052201
Neutron scattering experiments on a polycrystalline sample of the frustrated pyrochlore magnet Tb(2)Ti(2)O(7), which does not show any magnetic order down to 50 mK, have revealed that it shows condensation behavior below 0.4 K from a thermally fluctuating paramagnetic state to a spin-liquid ground state with quantum spin fluctuations. Energy spectra change from quasielastic scattering to a continuum with a double-peak structure at energies of 0 and 0.8 K in the spin-liquid state. Specific heat shows an anomaly at the crossover temperature. 相似文献
19.
Fletcher NH 《The Journal of the Acoustical Society of America》2000,108(2):821-826
Evidence is presented that the basic vocalized sound produced by some cockatoos, specifically the Australian sulfur-crested cockatoo (Cacatua galerita) and the gang-gang cockatoo (Callocephalon fimbriatum), has a chaotic acoustic structure rather than the harmonic structure characteristic of most birdsongs. These findings support those of Fee et al. [Nature (London) 395(3), 67-71 (1999)] on nonlinear period-doubling transitions in the song of the zebra finch (Taeniopygia guttata). It is suggested that syllables with chaotic structure may be a feature of the songs of many birds. 相似文献
20.
According to hydrodynamic, acoustic, and NMR studies the superfluid transition temperature of 3He in aerogel ( T(a)(c)) is significantly suppressed with respect to that of bulk 3He. We have found in the range of temperatures between T(c) and T(a)(c) a large and unexpected NMR satellite line attributable to the liquid inside the aerogel. We propose that this anomalous behavior of liquid 3He corresponds to a new type of superfluid ordering related to magnetic and possibly orbital coherence. 相似文献