排序方式: 共有127条查询结果,搜索用时 15 毫秒
121.
E. Gotsman E. Levin U. Maor J. S. Miller 《The European Physical Journal C - Particles and Fields》2008,57(4):689-709
In this paper we develop an approach to soft scattering processes at high energies which is based on two elements: the Good–Walker
mechanism for low mass diffraction and multi-pomeron interactions for high mass diffraction. The principal idea, which allows
us to specify the theory for pomeron interactions, is that the so called soft processes occur at rather short distances (r
2
∝1/〈p
t
〉2
∝
α′ℙ≈0.01 GeV−2), where perturbative QCD is valid. The value of the pomeron slope α′ℙ is obtained from a fit to the experimental data. Using this theoretical approach, we suggest a model that fits all soft data
in the ISR-Tevatron energy range: total, elastic, single and double diffractive cross sections, as well as the t dependence of the differential elastic cross section, and the mass dependence of single diffraction. In this model we calculate
the survival probability of diffractive Higgs production, and we obtain a value for this observable that is smaller than 1%
at the LHC energy range. 相似文献
122.
Methods for Thickness Determination of SiC Homoepilayers by Using Infrared Reflectance Spectroscopy 下载免费PDF全文
Infrared reflectance spectra have been widely used to measure layer thickness based either on calculation or on curve fitting, and two traditional methods for thickness determination have been studied. Considering the disadvantages of those two methods, we propose a new fitting model based on the fitting of the fringe order difference. In comparison with the measured results, the new fitting model shows its superiority not only for its stable and accurate results which have great agreement with the results from SEM, but also for its simple and quick fitting process. 相似文献
123.
J. P. Xu X. Zou C. X. Li P. T. Lai C. L. Chan 《Applied Physics A: Materials Science & Processing》2009,94(2):419-422
Reactive cosputtering is employed to prepare high-permittivity HfTiO gate dielectric on n-Ge substrate. Effects of Ge-surface
pretreatment on the interface and gate leakage properties of the dielectric are investigated. Excellent performances of Al/HfTiO/GeO
x
N
y
/n-Ge MOS capacitor with wet–NO surface pretreatment have been achieved with a interface-state density of 2.1×1011 eV−1 cm−2, equivalent oxide charge of −7.67×1011 cm−2 and gate leakage current density of 4.97×10−5 A/cm2 at V
g
=1 V. 相似文献
124.
Nasser Afify 《Journal of Physics and Chemistry of Solids》2008,69(7):1691-1697
In this work, a new method to study the transformation kinetics is introduced. With this method, the activation energy, Ec, for crystallization (phase transition or chemical reaction), the pre-exponential coefficient of effective overall reaction rate, ko, and the reaction order, n, can be determined. No approximation has been used in this method. This method can be used for isothermal and non-isothermal study. It is deduced from Avrami's equation without any approximation. This new method has been tested to study the amorphous-crystalline transformation kinetics under isothermal and non-isothermal conditions in the context of glassy selenium. The source of error is discussed. The calculated values of Ec, under isothermal and non-isothermal conditions are 75.3±2.5 and 79.4±2.3 kJ/mol, respectively. The predominant crystallization mechanism of the amorphous phase of glassy selenium in isothermal or non-isothermal conditions is one-dimensional growth. The deduced values of ko were found to be 19.4±0.9 and 20.8±0.7 s−1 for isothermal and non-isothermal conditions, respectively. Resulting values of the parameter, n, are compared with values obtained from other known methods used to study the reaction kinetics in thermal analyses. The difference in the results obtained with this method and the results obtained with other known methods is acceptable or lie within the experimental error range. 相似文献
125.
Shi Shusu Du Jiaxin Liu Lianshou 《The European Physical Journal A - Hadrons and Nuclei》2007,33(1):53-56
The inversion-asymmetry of the particle emission source in relativistic heavy-ion collision under the Bertsch-Pratt convention
is discussed and explicitly exhibited by a Monte Carlo model. The Gaussian source function popularly used in the HBT analysis
of relativistic heavy-ion collisions is invalid in this case. An inversion-asymmetric source function is suggested. A method
for extracting the inversion-asymmetry degree of the source together with the source size from experimental data is proposed. 相似文献
126.
J.C. Ewert G. Schmitz 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,17(3):391-403
A study of the reordering kinetics of ion-irradiated Ni3Al is presented. The development of long-range order during annealing treatments is measured by quantitative electron diffractometry.
According to the temperature dependence of the observed kinetics, the reaction is dominated by non-equilibrium vacancies.
As a consequence, the kinetics can be calibrated versus the absolute number of atomic jumps necessary to establish the observed degree of order. In order to analyse the experimental
data, Monte Carlo simulations are performed. It is shown that, beside the temperature dependence of the driving force, the
ordering efficiency of the vacancy jumps itself is temperature dependent due to different mobilities of the atomic species.
Received 6 December 1999 and Received in final form 23 June 2000 相似文献
127.
Orientational ordering in monolayers of solid hydrogen is discussed in view of recent experimental findings in NMR studies of (ortho)c-(para)1−c-hydrogen mixtures on boron nitride substrate reported for ortho-H2 concentrations 0.35≤c≤0.92 and temperatures 0.14≤T≤1.80 K. Analysis of the temperature-concentration behavior for the observed NMR frequency splitting is given on the basis of a two-dimension (J=1)c-(J=0)1−c-rotor model for which the fundamental parameters, quadrupolar coupling constant Γ0=0.50±0.03 K and the crystal-field amplitude V0=0.70±0.10 K, are derived from experiment. The two distinct para-rotational (PR) short-range ordered structures driven by positive and negative crystalline fields are described in terms of the local alignment and orientation of the polar principal axis. It is shown that they are rather different from the ferromagnetic-type ordering suggested earlier by Harris and Berlinsky as a unique PR structure. The common quadrupolar glass and a new hindered rotor phases found below the 2D site percolation threshold cp=0.72 are also discussed. 相似文献