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981.
Dabdoub Paz Eduardo D. Santana Maria Helena A. Eguchi Silvia Y. 《Applied biochemistry and biotechnology》1993,39(1):455-466
Applied Biochemistry and Biotechnology - The addition of α-alumina to the aqueous solution of sodium alginate for imobilization of viable cells allows the production of denser particles than... 相似文献
982.
Alexandre Cortés-Ayaso J. Carlos Díaz-Ramos Eduardo García-Río 《Annals of Global Analysis and Geometry》2008,34(2):185-193
It is shown that any four-dimensional Walker metric of nowhere zero scalar curvature has a natural almost para-Hermitian structure.
In contrast to the Goldberg–Sachs theorem, if this structure is self-dual and *-Einstein, it is symplectic but not necessarily
integrable. This is due to the non-diagonalizability of the self-dual Weyl conformal curvature tensor.
相似文献
983.
Alvaro Valencia Darren Ledermann Rodrigo Rivera Eduardo Bravo Marcelo Galvez 《国际流体数值方法杂志》2008,58(10):1081-1100
Hemodynamics plays an important role in the progression and rupture of cerebral aneurysms. The current work describes the blood flow dynamics and fluid–structure interaction in seven patient‐specific models of bifurcating cerebral aneurysms located in the anterior and posterior circulation regions of the circle of Willis. The models were obtained from 3D rotational angiography image data, and blood flow dynamics and fluid–structure interaction were studied under physiologically representative waveform of inflow. The arterial wall was assumed to be elastic, isotropic and homogeneous. The flow was assumed to be laminar, non‐Newtonian and incompressible. In one case, the effects of different model suppositions and boundary conditions were reported in detail. The fully coupled fluid and structure models were solved with the finite elements package ADINA. The vortex structure, pressure, wall shear stress (WSS), effective stress and displacement of the aneurysm wall showed large variations, depending on the morphology of the artery, aneurysm size and position. The time‐averaged WSS, effective stress and displacement at the aneurysm fundus vary between 0.17 and 4.86 Pa, 4.35 and 170.2 kPa and 0.16 and 0.74 mm, respectively, for the seven patient‐specific models of bifurcating cerebral aneurysms. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
984.
Eduardo Conde 《Operations Research Letters》2008,36(2):271-275
The minmax regret optimization model of the doubly weighted centdian location on trees is considered. Assuming that both types of weights, demands and relative importance of the customers, are partially known through interval estimates, an exact algorithm of complexity O(n3logn) is derived. This bound is improved in some special cases. 相似文献
985.
Harmonic-intensity analysis of normal and hoarse voices 总被引:1,自引:0,他引:1
N Hiraoka Y Kitazoe H Ueta S Tanaka M Tanabe 《The Journal of the Acoustical Society of America》1984,76(6):1648-1651
Objective evaluation of normal and hoarse voices is performed considering the characteristic that hoarse voices show a prominent fundamental frequency intensity compared with harmonics in the voice spectrum. The relative harmonic intensity Hr, obtained from a stable portion of the sustained vowel/a/, is defined as the intensity of the second and higher harmonics expressed as a percentage of the total voice intensity. Ninety-five percent of the normal voices examined have Hr larger than the critical value of 67.2%, whereas 90% of the hoarse voices have Hr smaller than the critical value. The harmonic-intensity analysis thus provides good discrimination between normal and hoarse voices. 相似文献
986.
Eduardo Mizraji 《Mathematical Logic Quarterly》1996,42(1):27-40
Vector logic is a mathematical model of the propositional calculus in which the logical variables are represented by vectors and the logical operations by matrices. In this framework, many tautologies of classical logic are intrinsic identities between operators and, consequently, they are valid beyond the bivalued domain. The operators can be expressed as Kronecker polynomials. These polynomials allow us to show that many important tautologies of classical logic are generated from basic operators via the operations called Type I and Type II products. Finally, it is described a matrix version of the Fredkin gate that extends its properties to the many-valued domain, and it is proved that the filtered Fredkin operators are second degree Kronecker polynomials that cannot be generated by Type I or Type II products. Mathematics Subject Classification: 03B05, 03B50. 相似文献
987.
988.
We have analyzed simultaneous recordings of respiration and heartbeat intervals in diabetic patients and control subjects. Our main findings are that in diabetic patients the heart beat-to-beat interval variability and cardiorespiratory crosscorrelation are decreased, the autocorrelation time of the interval series is increased, and the phase relation of the respiration with the heartbeat interval oscillations is often reversed in comparison with the control subjects. We have been able to reproduce the data using a biophysical model in which the time dependent input signal to the sinoatrial node was constituted of quasiperiodic and aperiodic components. The quasiperiodic input was obtained from the recording of the respiratory signal and the aperiodic input was obtained from selected realizations of correlated noise. Our study indicates that both input components to the sinoatrial node are modified in diabetic patients. 相似文献
989.
Katsufumi Tanaka Yuichiro Tanabe Takatoshi Morina Ryuichi Akiyama 《Liquid crystals》2008,35(3):253-264
Solid cast films with polydomain textures were prepared on a glass substrate with transparent interdigitated electrodes from an isotropic aqueous solution of hydroxypropyl cellulose via its liquid crystalline phase under the sinusoidal electric field with small amplitude and frequency of 0.05 V µm-1 and 105 Hz, respectively. The process was monitored using microdielectrometry as well as polarised optical microscopy. The apparent dielectric constant εr' and loss factor εr' sensitively changed with time depending on the process conditions. On the other hand, the logarithmic relation between εr' and εr' showed a single curve, when they were normalised by an effective portion of the electrostatic energy density estimated using each solid-film thickness. The conversion to the solid film was estimated during the process based on the concentration dependences of εr' and εr'. Characteristic times were reported for the onset of the biphasic phase, fully developed cholesteric phase and termination of the process. 相似文献
990.
We propose and study a numerical method for time discretization of linear and semilinear integro-partial differential equations that are intermediate between diffusion and wave equations, or are subdiffusive. The method uses convolution quadrature based on the second-order backward differentiation formula. Second-order error bounds of the time discretization and regularity estimates for the solution are shown in a unified way under weak assumptions on the data in a Banach space framework. Numerical experiments illustrate the theoretical results.