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1.
Inverse diffusion problems allow the diffusion coefficients to be determined from experimental concentration profiles. Solutions
of the inverse diffusion problem are unstable toward perturbations of the initial concentration profiles. By the example of
inverse diffusion problem solution for a model binary system it is demonstrated that the use of the production entropy to
minimize the discrepancy functional stabilizes the solution even for significant perturbations of the initial concentration
profile. The choice of the entropy production for the smoothing component of the discrepancy functional is physically adequate
to the formulated problem, and the entropy production can be used to solve inverse problems of heat and mass transfer.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 79–83, June, 2006. 相似文献
2.
N. S. Emel´yanova N. Yu. Shmatko N. A. Sanina S. M. Aldoshin 《Russian Chemical Bulletin》2017,66(10):1842-1846
Possible reactions of the mononuclear iron nitrosyl complex [Fe(SC(NH2)2)2(NO)2]Сl?H2O in an aqueous solution were studied using quantum chemical modeling. The electronic structures of the possible intermediates were examined by the NBO and AIM methods. The substitution of the thio ligand in the iron—sulfur nitrosyl complex by a water molecule and the formation of dimeric intermediate complexes were found to facilitate the NO-donation process. 相似文献
3.
Changes in the atomic and electronic structures of free NaCl clusters as the cluster size function are analyzed based on density
functional theory and the finite difference method. It is shown that the geometric atomic structure of clusters distorts more
with decreasing size. Along with this, an increase in the HOMO-LUMO gap is observed. 相似文献
4.
N. Yu. Shmatko N. A. Sanina D. V. Anokhin A. A. Piryazev D. A. Ivanov A. V. Kulikov S. M. Aldoshin 《Russian Chemical Bulletin》2015,64(7):1616-1622
New homogeneous water-soluble polyvinylpyrrolidone composites containing iron sulfur nitrosyl complexes as nitric oxide donors with antitumor and antiseptic activities were synthesized. The morphology of the composites in the solid state was examined by X-ray diffraction and scanning electron microscopy. The study by small-angle X-ray scattering showed that samples of the composites do not contain 10–100-nm aggregates and that iron sulfur nitrosyl complexes are uniformly distributed in polymer matrices. The percentage of NO-releasing iron sulfur nitrosyl complexes in the composites was determined by ESR spectroscopy. An amperometric analysis demonstrated that the polymer composites decompose to yield NO within a few seconds after the dissolution in water without additional thermal and photoactivation. The dependences of the amount of NO and the maximum level of NO release on the duration of the storage of aqueous solutions for all of the synthesized films were determined at pH 7.0. Some of the synthesized polymer composites retain NO-donor activity of the starting pharmacologically active iron nitrosyl complexes and can be recommended to be used as targeted delivery systems of this class of compounds to biological targets. 相似文献
5.
Nonlinear free vibration of functionally graded shallow shells with complex planform is investigated using the R-functions method and variational Ritz method. The proposed method is developed in the framework of the first-order shear deformation shallow shell theory. Effect of transverse shear strains and rotary inertia is taken into account. The properties of functionally graded materials are assumed to be varying continuously through the thickness according to a power law distribution. The Rayleigh–Ritz procedure is applied to obtain the frequency equation. Admissible functions are constructed by the R-functions theory. To implement the proposed approach, the corresponding software has been developed. Comprehensive numerical results for three types of shallow shells with positive, zero and negative curvature with complex planform are presented in tabular and graphical forms. The convergence of the natural frequencies with increasing number of admissible functions has been checked out. Effect of volume fraction exponent, geometry of a shape and boundary conditions on the natural and nonlinear frequencies is brought out. For simply supported rectangular FG shallow shells, the results obtained are compared with those available in the literature. Comparison demonstrates a good accuracy of the approach proposed. 相似文献
6.
A new approach is proposed to study the dynamic behavior of shells with an arbitrary planform weakened by surface cuts (cracks.) The approach is based on the method of R-functions. The computer simulation is carried out using the POLE-SHELL problem-oriented system, which implements the method of R-functions and variational methods. Numerical results are presented 相似文献
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8.
In present work, an effective method to research geometrically nonlinear free vibrations of elements of thin-walled constructions that can be modeled as laminated shallow shells with complex planform is applied. The proposed method is numerical–analytical. It is based on joint use of the R-functions theory, variational methods, Bubnov–Galerkin procedure and Runge–Kutta method. The mathematical formulation of the problem is performed in a framework of the refined first-order shallow shells theory. To implement the developed method, appropriate software was developed. New problems of linear and nonlinear vibrations of laminated shallow shells with clamped cutouts are solved. To confirm reliability of the obtained results, their comparison with the ones known in the literature is provided. Effect of boundary conditions is studied. 相似文献
9.
The carbon K-edge NEXAFS spectra of initial and fluorinated and hydrogenated single-wall carbon nanotubes (SWCNTs) are analyzed theoretically with regard to the polarization dependence. Differences in the polarized theoretical spectra of SWCNTs with zigzag and chair chiralities are shown. As a result of the comparison of experimental and theoretical carbon K-edge NEXAFS spectra of hydrogenated and fluorinated SWCNTs it is found that it is most probable that hydrogen atoms attach to the outer surface of the tube wall and fluorine atoms to the outer and inner surfaces of the SWCNT wall. Based on the analysis of polarized theoretical spectra of fluorinated and hydrogenated SWCNTs differences in the symmetry of the final states of C-H and C-F bonds are shown. 相似文献
10.