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941.
A technique for estimating and correcting nonuniform sampling distortions in magnetic resonance imagery is presented. The technique consists of first estimating the sampling grid distortion using a parametric model, and then estimating the uniformly sampled data by interpolation on the nonuniform grid. Parameterized models for two particular sampling grid distortion are presented. Maximum likelihood and maximum a posteriori estimators are developed for these distortions. Using computer simulated data, these estimators are shown to perform well. 相似文献
942.
I A Pelishenko V B Letski? A M Dediurin A N Galushkin E I Tikhonova 《Eksperimental?nai?a onkologii?a》1988,10(2):34-37
The simple method of polarographical testing of the peripheral blood serum is recommended as a part of the complex cancer diagnosis for the evaluation of the effectivity of cancer treatment and for the mass preventive examination. This method modified by I. A. Pelishenko (POISK-test) has permitted detecting a protein substance in the serum of cancer patients as well as in the serum both of the rats bearing Pliss sarcoma and in the serum of the irradiated dogs. It was proved that this protein indicates the presence of malignancy and represents polarographically active fraction of the alpha 1-unstable glycoprotein. This substance was designated as "Informative Pelishenko Protein" (IPP), and may be revealed by the polarographic indicator (IPM-01) made in Leningrad. 相似文献
943.
Margaret C. Etter Zofia Urbańczyk-Lipkowska Touradj M. Ameli Thomas W. Panunto 《Journal of chemical crystallography》1988,18(5):491-507
The crystal structures, solid-state infrared patterns, and thermal properties of two polymorphs of 4-nitrosalicylanilide are presented. In both polymorphs, intramolecular hydrogen bonds are found between the phenol oxygen and the amide proton, and intermolecular hydrogen bonds are found between the amide carbonyl oxygen and the phenol proton. These hydrogen bond patterns are compared to those found in other known salicylamide derivatives and an analysis is given of the factors contributing to preferences for intra- or intermolecular hydrogen bonds in these structures. Crystal data: polymorph, orthorhombic,Pbca,a=11.003(4),b=27.959(7),c=7.622(5) Å,Z=4,V=2345(3) Å3, andR=0.038 (1351 reflections); polymorph, monoclinic,P21/a,a=28.36(1),b=11.64(1),c=7.293(8) Å,=90.68(6)°,Z=8,V=2408 Å3, andR=0.043 (2425 reflections). 相似文献
944.
A. B. Voronetskii 《Journal of Mathematical Sciences》1988,43(5):2635-2645
Let f1, ..., fh be representatives of classes in the genus of a positive quadratic form f, ri(k) the number of representations of k by the form fi, (k) the value of the singular Hardy-Littlewood series, Ei the number of integer automorphisms of fi. We derive an expression for in terms of the values of singular series of genus 1 and 2. This expression is evaluated for the simplest model f(x)=x
1
2
+...+x
m
2
, m1 (mod 8), k is a prime in-integer, k=1(mod 8).Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 151, pp. 26–39, 1986. 相似文献
945.
C. Kessler 《Probability Theory and Related Fields》1988,78(2):253-259
Summary We show that, given a general Markov type property M, and a finite dimensional set of probability measures , the set of elements of having M can be described by finitely many quadratic equations. We apply the result to the problem of the global Markov property for nonextremal Gibbs states.This work was prepared during the author's stay at the University of Hull, England, and supported by the Science and Engineering Research Council of Great Britatin 相似文献
946.
In this paper we show that a hodograph method first introducedby Budd & Wheeler (1987) to develop a new numerical algorithmto solve the space charge equation ()=0 can be employedto derive all the known exact solutions, which have recentlybeen found by Smith (1988). All these solutions are shown tobe separable solutions of the equations resulting from the applicationof the hodograph transformation. We also briefly describe thisnew numerical method and use one of the exact solutions to demonstrateits accuracy. 相似文献
947.
C C Church 《The Journal of the Acoustical Society of America》1988,84(5):1758-1764
A reinterpretation of existing theory for rectified diffusion, the process by which bubbles in a sound field may grow in radius, is presented in order to quantitate the effect of acoustic microstreaming on bubble growth rates. The 1/t term in the growth rate equation is defined as the "decay term" and t as the "decay time," the time required for the gas concentration in the liquid contacting the bubble to rise (or fall) from its initial to its final value. In the absence of microstreaming, t is the duration of sonification. In the presence of microstreaming, t may be calculated from the streaming velocity and the bubble radius. A comparison between theory and the experimental results of Eller [A. Eller, J. Acoust. Soc. Am. 46, 1246-1250 (1969)] and of Gould [R.K. Gould, J. Acoust. Soc. Am. 56, 1740-1746 (1974)] shows reasonable agreement in the low kHz range. Theoretical results in the frequency range of 1-10 MHz at 1 and 4 bar are also presented. 相似文献
948.
For an Ising ferromagnet with nearest-neighbour interactions of strengthK and surface magnetic fieldh, the surface free energy in the presence of a positively (or negatively) magnetized zero-field bulk phase is shown to be analytic inh for Reh<K–/, where =2.96 ... and is the inverse temperature. This puts the lower boundK–/ on the values ofh at which wetting and layering transitions can take place. 相似文献
949.
The thermal conductivity of PrNi5 in the temperature range 0·5 to 20 K is investigated. The analysis of crystalline electric field effect on the experimentally obtained temperature dependence of the thermal conductivity indicates that beside the main electronic component also other contributions (phonons, magnetic excitons) can take place in the heat transport in this intermetallic compound.The authors would like to thank Dr. G. Eska for lending the sample and Dr. . Jáno for his interest in the work and stimulating discussions. 相似文献
950.
By applying magnetic fields up to 2 kG, the equation of state and the critical dynamics of a spin system near its critical point can be studied with the Mössbauer effect. As an example, the equation of state near the Curie temperature of iron is investigated yielding the critical exponent =4.84±0.15. 相似文献