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101.
As shown previously for two-dimensional geometries, anisotropy effects should not be ignored in electrical impedance tomography (EIT) and structural information is important for the reconstruction of anisotropic conductivities. Here, we describe the static reconstruction of an anisotropic conductivity distribution for the more realistic three-dimensional (3-D) case. Boundaries between different conductivity regions are anatomically constrained using magnetic resonance imaging (MRI) data. The values of the conductivities are then determined using gradient-type-algorithms in a nonlinear-indirect approach. At each iteration, the forward problem is solved by the finite element method. The approach is used to reconstruct the 3-D conductivity profile of a canine torso. Both computational performance and simulated reconstruction results are presented together with a detailed study on the sensitivity of the prediction error with respect to different parameters. In particular, the use of an intracavity catheter to better extract interior conductivities is demonstrated 相似文献
102.
V. B. Baiburin Yu. P. Volkov E. M. Il’in S. V. Semenov 《Technical Physics Letters》2002,28(12):981-982
The surface of a palladium-barium cathode was studied using scanning probe microscopy techniques. Data from the tunneling spectroscopy showed the pattern of the electron work function distribution over a microscopic region on the emitter surface. This pattern is compared to the distribution of various phases in the palladium-barium alloy employed. 相似文献
103.
E. V. Astrova V. V. Ratnikov R. F. Vitman A. A. Lebedev A. D. Remenyuk Yu. V. Rud’ 《Semiconductors》1997,31(10):1084-1090
The results of an investigation of layers of porous silicon (PS), which was obtained by electrochemical etching of p-Si under different illumination conditions — natural light, incandescent light, and light from a mercury lamp with and without
a filter — are reported. The structure of the layers was studied by double-crystal x-ray diffractometry, the composition was
monitored by means of the IR absorption spectra, and the radiative properties were monitored according to the photoluminescence
(PL) spectra. It was established that electrochemical etching under illumination produces PS with a higher porosity and more
intense PL whose maximum is shifted into the short-wavelength region. These changes are accompanied by a large disordering
of the structure and an increase in the oxygen content in the layer. It is concluded that illumination accelerates the chemical
interaction of PS with the electrolyte due to oxidation. High-porosity porous silicon stored in air exhibits quenching of
PL. Conversely, PL is excited in layers with a lower porosity. Aging of PS is characterized by an increase in the microdeformation
of the layers, a decrease in the crystallite sizes with a partial loss of coherence between the crystallites and the substrate,
and an increase in the fraction of the amorphous phase.
Fiz. Tekh. Poluprovodn. 31, 1261–1268 (October 1997) 相似文献
104.
V. B. Mikhailov A. N. Chernenko A. G. Kas’yanov A. B. Shutikhin L. I. Bryukhanov 《Metallurgist》1997,41(9-11):314-316
The Zlatoust Metallurgical Plant has developed a technology that employs semi-dry pressing to make two-layer (composite) heat-insulating inserts for ingot-mold hot tops. The working layer is made of a mixture of materials based on quartz sand, while the insulating layer is based on foamed vermiculate. The binders are sodium silicate solution and commercial lignosulfonate with a density of 1.12–1.20 g/cm3. 相似文献
105.
Translated from Kibernetika i Sistemnyi Analiz, No. 5, pp. 137–145, September–October, 1993. 相似文献
106.
Yu. B. Afanas’ev E. V. Mokrushina A. A. Nechitailov V. V. Prokof’ev 《Technical Physics Letters》1997,23(3):181-183
The parameters of Bi12TiO20 crystals grown with bismuth oxide of different degrees of purity were measured by a holographic recording technique in an
external ac electric field and were compared with a crystal specially doped with chromium. Various crystal parameters such
as the diffusion length of the photoexcited carriers and the Debye screening length were determined. It was found that the
absorption spectrum of the material and the holographic recording efficiency were strongly influenced by light chromium doping
and by insufficient purity of the starting mixture.
Pis’ma Zh. Tekh. Fiz. 23, 27–32 (March 12, 1997) 相似文献
107.
108.
109.
I. V. Gervas’eva D. P. Rodionov Yu. V. Khlebnikova N. F. Vil’danova A. S. Shtyrlov G. A. Dosovitskii A. R. Kaul’ 《The Physics of Metals and Metallography》2007,103(6):600-608
The texture, structure, and magnetic and mechanical properties of thin ribbons of nickel-palladium alloys have been studied. It has been demonstrated that in Ni94Pd6 and Ni92.5Pd5W2.5 alloys, a sharp cube texture can be formed that is stable up to rather high annealing temperatures. Segregation of palladium atoms to surface layers of ribbons has been found, which gives additional advantages for using these ribbons as substrates for epitaxial deposition of high-temperature superconductors. 相似文献
110.
E. S. Gorkunov S. Yu. Mitropol’skaya A. M. Povolotskaya 《Russian Journal of Nondestructive Testing》2005,41(3):175-181
Stacks of steel plates having different values of magnetic hardness and separated with nonferromagnetic gaps are investigated. The coercive force and the residual magnetic induction of a stack measured in a closed magnetic circuit depend on the layout of the plates in the stack and on the thickness of nonmagnetic gaps between them.__________Translated from Defektoskopiya, Vol. 41, No. 3, 2005, pp. 55–62.Original Russian Text Copyright © 2005 by Gorkunov, Mitropol’skaya, Povolotskaya.Dedicated to the Anniversary of the 100th Birthday of Corresponding Member of the Russian Academy of Sciences M. N. Mikheev 相似文献