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51.
The boundary element spline collocation method is studied for the time-fractional diffusion equation in a bounded two-dimensional
domain. We represent the solution as the single layer potential which leads to a Volterra integral equation of the first kind.
We discretize the boundary integral equation with the spline collocation method on uniform meshes both in spatial and time
variables. In the stability analysis we utilize the Fourier analysis technique developed for anisotropic pseudodifferential
equations. We prove that the collocation solution is quasi-optimal under some stability condition for the mesh parameters.
We have to assume that the mesh parameter in time satisfies
(ht=c h\frac2a)(h_t=c h^{\frac{2}{\alpha}}), where (h) is the spatial mesh parameter. 相似文献
52.
Jyrki K. Kauppinen Ilkka K. Salomaa Jari O. Partanen Matti R. Hollberg 《Optical Review》1997,4(2):293-296
The carousel interferometer is a new type of an interferometer, which has been invented at the University of Turku. It consists of a beamsplitter and five plane mirrors. Four of the mirrors are mounted on a carousel, which rotates back and forth. We have modified the interferometer for use in the Fourier-transform ultraviolet (FT-UV) spectroscopy. Test measurement with plasma radiation gives favourable results. The most important property, which makes the carousel interferometer suitable for UV measurements, is its good stability in modulation.Presented at 1996 International Workshop on Interferometry (IWI ‘96), August 27–29, Saitama, Japan. 相似文献
53.
Matti Jrvisalo Ilkka Niemel 《Journal of Algorithms in Cognition, Informatics and Logic》2008,63(1-3):90
The techniques for making decisions (branching) play a central role in complete methods for solving structured instances of propositional satisfiability (SAT). Experimental case studies in specific problem domains have shown that in some cases SAT solvers can determine satisfiability faster if branching in the solver is restricted to a subset of the variables at hand. The underlying idea in these approaches is to prune the search space substantially by restricting branching to strong backdoor sets of variables which guarantee completeness of the search. In this paper we present an extensive experimental evaluation of the effects of structure-based branching restrictions on the efficiency of solving structural SAT instances. Previous work is extended in a number of ways. We study state-of-the-art solver techniques, including clause learning and related heuristics. We provide a thorough analysis of the effect of branching restrictions on the inner workings of the solver, going deeper than merely measuring the solution time. Extending previous studies which have focused on input-restricted branching, we also consider relaxed branching restrictions that are based on underlying structural properties of the variables. 相似文献
54.
Conformal invariants and quasiregular mappings 总被引:2,自引:0,他引:2
Matti Vuorinen 《Journal d'Analyse Mathématique》1985,45(1):69-115
55.
Matti Varpula Pentti Kiilholma Pekka Klemi Markku Komu 《Magnetic resonance imaging》1994,12(8):1139-1145
The purpose of this investigation was to analyze the normal anatomy and leiomyomas of the uterus with an ultra low field (0.02 T) magnetic resonance imaging (MRI) device. MR imaging was performed on 18 uteri, 11 of which were imaged both preoperatively (in vivo) and as an operative specimen (in vitro), 6 only as an operative specimen, and 1 only preoperatively. All uteri were examined histologically after imaging. The junctional zone was much better delineated in vivo than in vitro, indicating that its appearance on MR is partly due to blood flow. No structures contributing to its visibility in vitro could be demonstrated histologically. Twenty leiomyomas (size range 7–79 mm) in 12 uteri were found with MRI. They were slightly better discerned in vivo than in vitro. The leiomyomas, having no degenerative changes, had a signal intensity which was the same or lower than that of the myometrium. On images obtained in vitro the signal intensity of these leiomyomas relative to that of myometrium correlated directly with their muscular content (R = 0.74, p = .002). The authors conclude that the junctional zone is a sum of physiological and structural factors, the latter being responsible for its in vitro delineation. MR imaging of the uterus in vitro did not give more information than MR imaging in vivo. All leiomyomas larger than 10 mm could be detected, indicating that MR imaging at 0.02 T is an accurate method for the imaging of the uterine leiomyomas. 相似文献
56.
Analysis of ALD-processed thin films by ion-beam techniques 总被引:1,自引:0,他引:1
Putkonen M Sajavaara T Niinistö L Keinonen J 《Analytical and bioanalytical chemistry》2005,382(8):1791-1799
This review introduces the possibilities of ion-beam techniques for the analysis of thin films and thin-film structures processed by atomic layer deposition (ALD). The characteristic features of ALD are also presented. The analytical techniques discussed include RBS, NRA and ERDA with its variants, viz. the TOF-ERDA and HI-ERDA. The thin film examples are taken from flat-panel display technology (TFEL structures) and the semiconductor industry (high-k insulators).Dedicated to the memory of Wilhelm Fresenius 相似文献
57.
Olli Martio Vladimir Miklyukov Matti Vuorinen 《Proceedings of the American Mathematical Society》2005,133(5):1451-1458
The system which yields Beltrami's system if , is considered. Under a condition for the coefficients a non-existence theorem is proved.
58.
M.Matti Maricq 《Chemical physics》1985,100(2):203-215
The average hamiltonian theory is used to examine the effect of molecular vibration on low-energy scattering. When the relative motion of the colliding molecules is slow on the timescale of molecular vibration, it is appropriate to transform the problem into an oscillating reference frame and to describe the collision in that frame by the average hamiltonian over one period of oscillation. The first-order result is identical to the distorted-wave Born approximation. High-order corrections introduce phase shifts for elastic scattering due to molecular vibration and provide transition amplitudes for inelastic scattering. The extent to which the higher-order corrections modify the distorted waves establishes criteria for the validity of the DWA. These criteria are used to examine recent distorted-wave calculations of V-V energy transfer rate constants. 相似文献
59.
60.
Alegria EC Martins LM Haukka M Pombeiro AJ 《Dalton transactions (Cambridge, England : 2003)》2006,(41):4954-4961
The trioxo [ReO(3){SO(3)C(pz)(3)}] (1) (pz = pyrazolyl) and oxo [ReOCl{SO(3)C(pz)(3)}(PPh(3))]Cl (2) compounds with tris(pyrazolyl)methanesulfonate were obtained by treatment of Re(2)O(7) or [ReOCl(3)(PPh(3))(2)], respectively, with Li[SO(3)C(pz)(3)], whereas [ReCl(3){HC(pz)(3)}] (3), [ReCl(3){HC(3,5-Me(2)pz)(3)}] (4) and [ReCl(4){eta(2)-HC(pz)(3)}] (5) were prepared by reaction of [ReOCl(3)(PPh(3))(2)] (3,4) or [ReCl(4)(NCMe)(2)] (5) with hydrotris(pyrazolyl)methane HC(pz)(3) (3,5) or hydrotris(3,5-dimethyl-1-pyrazolyl)methane HC(3,5-Me(2)pz)(3) (4). [ReO{SO(3)C(pz)(3)}{OC(CH(3))(2)pz}][ReO(4)] 6, with a chelated pyrazolyl-alkoxide, was derived from an unprecedented ketone-pyrazolyl coupling on reaction of crude 1 with acetone. The compounds have been characterized by elemental analyses, IR and NMR spectroscopies, FAB-MS spectrometry and cyclic voltammetry and, in the case of 5 and 6, also by single-crystal X-ray diffraction. The electrochemical E(L) Lever parameter has been estimated, for the first time, for the SO(3)C(pz)(3)(-) and oxo ligands allowing the measurement of their electron-donor character and comparison with other ligands. Compounds 1, 2 and 6 appear to be the first tris(pyrazolyl)methanesulfonate complexes of rhenium to be reported. 相似文献