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211.
Z. Adonyi 《Journal of Thermal Analysis and Calorimetry》1994,42(2-3):491-503
Dimensionless number has been developed and introduced for quantitative analysis of the effect of thermogravimetric measuring factors like sample quantity, heating rate, etc. The TG, DTG and T data of different thermogravimetric measurements can be used directly for calculation of the three constants of analogy. TG data of CaCO3 measured in very different conditions show the method of transformation and its applicability for calculation of the correlation of measurements. 相似文献
212.
Z. D. Zivkovic 《Journal of Thermal Analysis and Calorimetry》1994,41(1):99-104
The results of comparative thermal analysis (TG-DTG-DTA-DSC) of the thermal decomposition of hexamminecobalt(III) chloride in air atmosphere are reported. The kinetics and mechanism of the thermal decomposition, the process enthalpy and the variation in specific thermal capacity of the solid product reaction with temperature were determined. 相似文献
213.
J. M. Godoy M. L. Godoy Z. L. Carvalho D. C. Lauria 《Journal of Radioanalytical and Nuclear Chemistry》1994,183(1):19-26
A short overview of HPLC column packings is presented. The properties of chromatographic carriers and the possibilities to combine the solid matrices with organic polymeric stationary phases are elucidated in detail. The latest achievements and anticipated future developments in the area are outlined. 相似文献
214.
Z. Szeglowski H. Bruchertseifer V. B. Brudanin G. V. Buklanov O. Constantinescu Dinh Thi Lien V. P. Domanov L. I. Guseva M. Hussonnois G. S. Tikhomirova I. Zvara Yu. Ts. Oganessian 《Journal of Radioanalytical and Nuclear Chemistry》1994,186(4):353-359
The short-lived isotopes of W and their descendants have been isolated from the products of the bombardment of144Sm with24Mg by a fast continuous ion-exchange method, using HF solution media. The feasibility of this method for isolation of element 106 is discussed. 相似文献
215.
X.T Zhang Y.C LiuZ.Z Zhi J.Y ZhangY.M Lu D.Z ShenW Xu X.W FanX.G Kong 《Journal of luminescence》2002,99(2):149-154
The properties of the excitonic luminescence for nanocrystalline ZnO thin films are investigated by using the dependence of excitonic photoluminescence (PL) spectra on temperature. The ZnO thin films are prepared by thermal oxidation of ZnS films prepared by low-pressure metalorganic chemical vapor deposition (LP-MOCVD) technique. The X-ray diffraction (XRD) indicates that ZnO thin films have a polycrystalline hexagonal wurtzite structure with a preferred (0 0 2) orientation. A strong ultraviolet (UV) emission peak at 3.26 eV is observed, while the deep-level emission band is barely observable at room temperature. The strength of the exciton-longitudinal-optical (LO) phonon coupling is deduced from the temperature dependence of the full-width at half-maximum (FWHM) of the fundamental excitonic peak, decrease in exciton-longitudinal-optical (LO) phonon coupling strength is due to the quantum confinement effect. 相似文献
216.
Summary This paper uses Hamiltonian structures to study the problem of the limit of three-dimensional (3D) elastic models to shell
and rod models. In the case of shells, we show that the Hamiltonian structure for a three-dimensional elastic body converges,
in a sense made precise, to that for a shell model described by a one-director Cosserat surface as the thickness goes to zero.
We study limiting procedures that give rise to unconstrained as well as constrained Cosserat director models. The case of
a rod is also considered and similar convergence results are established, with the limiting model being a geometrically exact
director rod model (in the framework developed by Antman, Simo, and coworkers). The resulting model may or may not have constraints,
depending on the nature of the constitutive relations and their behavior under the limiting procedure.
The closeness of Hamiltonian structures is measured by the closeness of Poisson brackets on certain classes of functions,
as well as the Hamiltonians. This provides one way of justifying the dynamic one-director model for shells. Another way of
stating the convergence result is that there is an almost-Poisson embedding from the phase space of the shell to the phase
space of the 3D elastic body, which implies that, in the sense of Hamiltonian structures, the dynamics of the elastic body
is close to that of the shell. The constitutive equations of the 3D model and their behavior as the thickness tends to zero
dictates whether the limiting 2D model is a constrained or an unconstrained director model.
We apply our theory in the specific case of a 3D Saint Venant-Kirchhoff material andderive the corresponding limiting shell and rod theories. The limiting shell model is an interesting Kirchhoff-like shell model
in which the stored energy function is explicitly derived in terms of the shell curvature. For rods, one gets (with an additional
inextensibility constraint) a one-director Kirchhoff elastic rod model, which reduces to the well-known Euler elastica if
one adds an additional single constraint that the director lines up with the Frenet frame.
This paper is dedicated to the memory of Juan C. Simo
This paper was solicited by the editors to be part of a volume dedicated to the memory of Juan Simo. 相似文献
217.
We give characterizations of continuous distributions in terms of moments of order statistics when the sample size is random.
In particular, we characterize uniform, exponential, Pareto, and logistic distributions. Special cases of a random sample
size (logarithmic series, geometrical, truncated binomial, truncated negative binomial, and truncated Poisson distribution)
are also considered.
Proceedings of the XVII Seminar on Stability Problems for Stochastic Models, Kazan, Russia, 1995, Part I. 相似文献
218.
Yuval Z. Flicker 《Mathematische Annalen》1993,297(1):199-219
219.
The magnetic and electric properties of the Sr2FeMoO6 compound produced under different preparation conditions were studied. Depending on the preparation condition, a strong variation in the nonmagnetic SrMoO4 impurity content was found, which in turn determined the metallic or semiconducting behavior of the resistivity of the Sr2FeMoO6 compound. There was also evidence that SrMoO4 played a crucial role in modifying the low magnetic field intergrain tunneling magnetoresistance in Sr2FeMoO6. In addition, we have established a simple method to prepare the single phase Sr2FeMoO6 polycrystals. 相似文献
220.