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排序方式: 共有114条查询结果,搜索用时 46 毫秒
31.
We prove the existence of C0 semigroups related to some birth-and-death type infinite systems of ODEs with possibly unbounded coefficients, in the scale
of spaces lp,
For some particular cases we also provide a characterization of the spectra of their generators. For the proof of the generation
theorem in the case p > 1 we extend the Chernoff perturbation result ([9]) on relatively bounded perturbations of generators.
The results presented here have been used in [5] and they play important role for analysing chaoticity of dynamical systems
considered there. As a by-product of our approach we obtain a result related to the classical Shubin theorem [20]. We show
that this theorem, saying that for a class of bounded infinite matrices the spectrum of the corresponding maximal operator
in lp is independent on
cannot be extended to unbounded matrices. 相似文献
32.
33.
Marian Kryszewski Jerzy Morawiec Miroslaw Pluta Pawel Uznaski 《Macromolecular Symposia》1994,78(1):171-186
Structure and properties of polyolefins-poly(ethylene oxide) (PEO) blends were studied by combination of thermal analysis, light microscopy and fluorescence probe technique. Mixing and preparation conditions influence the calorimetric behavior, changing heat and temperature of melting and crystallinity degree of blended polymers. Values of the static mechanical parameters as well as flow characteristic parameters of the blends are lower for the higher PEO fraction in the samples. Fluorescence investigation of pyrene (changes in the vibrational fine structure) showed a nonhomogeneous distribution of the probe molecules between polyolefin and PEO environment. From these data the partition coefficient between polyolefin and PEO phase can be calculated and correlated with the crystallinity changes of the mixture composition. 相似文献
34.
Andrzej W. Domanski Rafal Cieslak Miroslaw A. Karpierz Daniel Budaszewski Tomasz R. Wolinski 《Central European Journal of Physics》2008,6(3):628-633
This paper analyzes the second harmonic generation (SHG) efficiency of light with partial temporal coherence due to depolarization
effects in birefringent media. It discusses relations between SHG efficiency fading, light source spectrum, crystal birefringence,
and phase matching conditions. The efficiency of SHG pumped by the partially coherent light beam that may depolarize light
in nonlinear birefringent crystal is also analyzed. The basic theory of SHG with its modification for partially coherent light
with depolarization and some numerical calculations of the SHG process are described.
Presented at 9-th International Workshop on Nonlinear Optics Applications, NOA 207, May 17–20, 2007, Świnoujście, Poland 相似文献
35.
T.L. Khoo F.M. Bernthal C.L. Dors M. Piiparinen S. Saha P.J. Daly J. Meyer-Ter-Vehn 《Physics letters. [Part B]》1976,60(4):341-343
Positive parity levels in 191Pt obtained from (α, xnγ) reactions and β-decay are presented as a first example of a rather complete level family. The spectrum confirms triaxial shapes found before from and proton structures in this mass region. In addition to the usual decoupled yrast band, a second ΔI = 2 band within the family, built on a low-lying state, is observed in agreement with theory. 相似文献
36.
Miroslaw Krzyzanski 《Annali di Matematica Pura ed Applicata》1955,40(1):89-97
Résumé L'auteur construit la solution fondamentale pour l'équation aux dérivées partielles du type parabolique à deux variables indépendantes
en partant de celle de l'équation
construite parJ. Hadamard.
à Mauro Picone pour son 70me anniversaire. 相似文献
37.
Yukari Tajika Yumi Yasuoka Hiroyuki Nagahama Toshiyuki Suzuki Yoshimi Homma Tetsuo Ishikawa Shinji Tokonami Takahiro Mukai Miroslaw Janik Atsuyuki Sorimachi Masahiro Hosoda 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(3):1709-1714
Gas-flow ionization chambers for radioisotope (RI) monitoring systems at RI institutes throughout Japan are commonly used to measure RIs which leak from the RI institutes. Before the Japan’s 2011 Tohoku earthquake [11 March 2011, moment magnitude (M w) 9.0], ionization current data measured with a gas-flow ionization chamber at the RI institute of Fukushima Medical University were found to change. The question we must raise is whether the variation ionization current can be considered to the variation of outdoor radon concentration. The conversion factors (from ionization current to radon concentration in air) of the gas-flow ionization chamber can be obtained by measuring four levels of radon concentration (outdoor air, indoor air, high level and radon-free gas) with an AlphaGUARD monitor and the chamber itself. The two gas-flow ionization chambers consist of the air intake and terminal exhaust duct of the RI institute. It was found that the radon concentration in the exhaust air was the same as that in the air intake. This study provided evidence that variations of outdoor radon concentration could be determined using gas-flow ionization chambers for RI monitoring systems. 相似文献
38.
Anna Kovářová Vladimíra Novotná Milada Glogarová Miroslaw Salamonczyk Damian Pociecha 《Liquid crystals》2013,40(12):1501-1513
New liquid crystalline (LC) compounds containing the [2]benzothiophene chromophore unit have been synthesised and their mesomorphic properties studied. Mesomorphic and fluorescent properties have been modified by various chemical moieties. Among others, terminal fluoroalkyl and/or chiral chains were introduced to stabilise mesophases and support the formation of polar phases. In spite of the bent shape due to the central 1,3-diphenylbenzo[c]thiophene unit, all compounds exhibit phases typical for the rod-like LC: nematic, smectic A and smectic C or their chiral analogues using the chiral (S)-C2H5CH(CH3)(CH2)6CO or (S)-C10H21OCH(CH3)CO chain. The orientational order in the nematic phase was studied by polarised infrared measurements. The fluorescent properties of the studied compounds have been measured and their parameters established. 相似文献
39.
Kwasny M Piccardi A Alberucci A Peccianti M Kaczmarek M Karpierz MA Assanto G 《Optics letters》2011,36(13):2566-2568
We investigate the attractive interaction between spatial solitons in nematic liquid crystals with a tunable nonlinearity and a constant nonlocality. The experimental study, carried out by controlling the orientation of the optic axis via the electro-optic response, shows how the interactions depend on reorientation, in excellent agreement with a model accounting for the anisotropic nature of the dielectric. 相似文献
40.
Concetta De Santi Bjørn Altermark Marcin Miroslaw Pierechod Luca Ambrosino Donatella de Pascale Nils-Peder Willassen 《BMC biochemistry》2016,17(1):1