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271.
The photo-detachment cross section of H^- near two parallel elastic interfaces is derived and calculated by using the closed orbit theory. The photo-detachment cross section of H^- near two interfaces is shown to exhibit multi-periodic oscillations when the distance between the H^- and the interface is varied. Each peak in the Fourier transformed photo-detachment cross section corresponds to the length of a closed orbit, which is quite similar to the case of atomic spontaneous emissions in a dielectric slab. This study provides a new understanding of the photo=detachment process of H^- in the presence of interfaces.  相似文献   
272.
We introduce a solver method for mobile and immobile transport regions. The motivation is driven by transport processes in porous media (e.g. waste disposal, chemical deposition processes). We analyze the coupled transport‐reaction equation with mobile and immobile areas. We apply analytical methods, such as Laplace‐transformation, and for the numerical methods we apply Godunov's scheme, see (Mat. Sb. 1959; 47 :271–306; Finite Volume Methods for Hyperbolic Problems. Cambridge University Press: Cambridge, 2002). The method is based numerically on flux‐based characteristic methods and is an attractive alternative to the classical higher‐order TVD methods, see (J. Comput. Phys. 1993; 49 :357–393). In this paper, we will focus on the derivation of analytical solutions for general and special solutions of the characteristic methods that are embedded in a finite‐volume method. At the end of the paper, we illustrate the higher‐order method for different benchmark problems. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   
273.
We consider the estimation of three-dimensional ROC surfaces for continuous tests given covariates.Three way ROC analysis is important in our motivating example where patients with Alzheimer’s disease are usually classified into three categories and should receive different category-specific medical treatment.There has been no discussion on how covariates affect the three way ROC analysis.We propose a regression framework induced from the relationship between test results and covariates.We consider several practical cases and the corresponding inference procedures.Simulations are conducted to validate our methodology.The application on the motivating example illustrates clearly the age and sex effects on the accuracy for Mini-Mental State Examination of Alzheimer’s disease.  相似文献   
274.
The transformation from ferrihydrite to various iron oxides and iron oxyhydroxides has been given much attention not only in environmental science and geochemistry but also in biology and material science. This laboratory study attempted to investigate Fe(II)-induced transformation of ferrihydrite in sulfate-rich medium. The results indicate that the transformation in sulfate-rich medium differs from that in Cl medium in the species, the amount and the morphology of products and transformation rate. Lepidocrocite is a main ingredient in the product in Cl medium at room temperature (RT), while goethite is the only product in SO42− medium at RT. Goethite particles obtained in Cl medium are star-like but rod-like in SO42− medium. The transformation rate in the latter medium is obviously slower than that in the former medium. The formation of lepidocrocite depends on both the ionic strength of the system and the dissolution rate of ferrihydrite.  相似文献   
275.
Guojun Deng 《Tetrahedron letters》2008,49(39):5601-5604
A novel direct addition of cycloalkanes to imines mediated by peroxide was developed. The reaction tolerates a wide range of functionalities as well as aqueous conditions.  相似文献   
276.
An asymptotic formula for periodic eigenvalues, due to Titchmarsh, is taken to a higher degree of accuracy using a Prüfer transformation method, not depending on Floquet theory. With the idea of the rotation number, this method is then extended to the p-Laplacian.  相似文献   
277.
After the cultured cells from Hyoscyamus muticus + Nicotiana tabacum somatic hybridswere cocultivated with different virulent strains of Agrobacterium tumefaciens harboringoctopine- type Ti plasmid or nopaline- type Ti plasmid using the transformation procedurein vitro developed in the present investigation, the TiT- DNA genes were introducedinto the host cells. The onc genes and ocs or nos genes located on TiT- DNA were expres-sed in transformed colonies derived from the cocultivated cells. Although the platingefficiencies of recipient cells were reduced by the agrobacterial treatment, the frequenciesof phytohormone autotrophy ranged from 33.9 to 76 .8% in the cells infected with viru-lent strains in hormone- free conditions, and the frequencies of opine synthase activityamounted to 9.7- 47 .5%. Teratomatous shoots were regenerated from the transformed col-onies. During the course of culture the shoots were no longer to lengthen when theygrew up to 1 -3 cm in length, and they could not be rooted. Follo  相似文献   
278.
We evaluate two coordinate transformation techniques in combination with grid stretching for pricing basket options in a sparse grid setting. The sparse grid technique is a basic technique for solving a high-dimensional partial differential equation. By creating a small hypercube sub-grid in the ‘composite’ sparse grid we can also determine hedge parameters accurately. We evaluate these techniques for multi-asset examples with up to five underlying assets in the basket.  相似文献   
279.
The effects of dilatational phase transformation on the target strength of ceramic materials are investigated based on Tate's model. The constitutive behavior of materials in different regions (elastic, cracked, plastic and phase transformation) are taken into account. It is found that, with a proper choice of material parameters, the dilatational phase transformation can increase effectively the target strengthR. This would be of importance in penetration-resistance design. This work is partially supported by the Excellent Youth Foundation of Harbin Institute of Technology  相似文献   
280.
Partially substituting Sb for In, we found an irreversible transformation of martensite to intermartensite at 90 K in Ni50Mn34In12Sb4 alloy during heating. The reverse transformation of martensite and intermartensite to the parent phase induced by a magnetic field has been investigated. The results indicate that, if a sufficiently high magnetic field is applied, the intermartensite state is no longer necessary as an intermediate state. Thus, a difference of the transformation originating from magnetic and from thermal energies has been found. In this competition, lattice distortions play an important role to promote the occurrence of the intermediate intermartensitic path.  相似文献   
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