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排序方式: 共有10000条查询结果,搜索用时 15 毫秒
931.
I. R. Martin V. D. Rodriguez M. Morales U. R. Rodriguez-Mendoza V. Lavin 《Journal of Applied Spectroscopy》1995,62(5):865-871
This work has been partially supported by Gobierno Autonomo de Canarias under contact number 226–265/93. 相似文献
932.
We discuss possible experiments which can exploit recently-developed techniques to accumulate, store, and manipulate low-energy positrons to measure the parameters associated with positron annihilation radiation from media of astrophysical interest. Media discussed include collections of dust grains, partially ionized gases, He, H2, and other molecular gases and gas mixtures, including polycyclic aromatic hydrocarbon (PAH) molecules relevant to the interstellar medium. 相似文献
933.
934.
Recently we used a method of stable analytic extrapolation to test whether strictly local duality between the asymptotic and the resonance region, which is believed to be valid in QCD, appears already at the present stage of QCD calculations. Probing the QCD ?-amplitude, we found a prominent bump structure in the resonance region, i.e. a rather direct evidence for the validity of local duality. In the present paper we confirm and extend this result by giving two further applications, theA 1-meson and the ?-meson. While we do not meet theA 1, as was to be expected since other sum rules can not separate it from the continuum, too, the extrapolation of the ?-amplitude leads to an enormous bump. Comparing this ?-bump with our ?-bump, we recover at least qualitatively the real proportions. 相似文献
935.
M. I. Dykman D. G. Luchinsky R. Mannella P. V. E. McClintock N. D. Stein N. G. Stocks 《Il Nuovo Cimento D》1995,17(7-8):661-683
Summary We outline the historical development of stochastic resonance (SR), a phenomenon in which the signal and/or the signal-to-noise
ratio in a nonlinear system increase with increasing intensity of noise. We discuss basic theoretical ideas explaining and
describing SR, and we review some revealing experimental data that place SR within the wider context of statistical physics.
We emphasize the close relationship of SR to some effects that are well known in condensed-matter physics.
Paper presented at the International Workshop ?Fluctuations in Physics and Biology: Stochastic Resonance, Signal Processing
and Related Phenomena?, Elba, 5–10 June 1994. 相似文献
936.
It is experimentally demonstrated that the image resolution from an in-line Fraunhofer hologram degrades appreciably when the centre of the diffraction pattern from a 5-bar resolution target is located asymmetrically in the hologram aperture. This effect is confirmed and analysed using calculated and experimentally measured images from holograms of a one-dimensional wire. Increasing asymmetry results in an increasing error in the measured linewidth, and a reduction of image resolution. A simple model based on average fringe contrast is used to predict this decrease in resolution with transverse object position. 相似文献
937.
We consider a flower-like Ising model, in which there are some additional bonds (in the “flower-core”) compared to a pure
Ising chain. To understand the behaviour of this system and particularly the competition between ferromagnetic (usual) bonds
along the chain and antiferromagnetic (additional) bonds across the chain, we study analytically and iteratively the main
thermodynamic quantities. Very interesting is, in the zero-field and zero-temperature limit, the behaviour of the magnetization
and the susceptibility, closely related to the ground state configurations and their degeneracies. This degeneracy explains
the existence of non-zero entropy at zero temperature, in our results. Also, this model could be useful for the experimental
investigations in studying the saturation curves for the enzyme kinetics or the melting curves for DNA-denaturation in some
flower-like configurations. 相似文献
938.
939.
We calculate the spin fluctuation spectra of VN and NbN in the relevant frequency- and wave vector regime. Significant quantitative differences between the dynamical spin susceptibilities of both substances are found. While in the case of VN their amplitudes are large, especially towards the Brillouin zone boundary and for frequencies below 1 eV, enhancement effects in NbN are of minor importance. 相似文献
940.