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961.
Rennies J Brand T Kollmeier B 《The Journal of the Acoustical Society of America》2011,130(5):2999-3012
Reverberation usually degrades speech intelligibility for spatially separated speech and noise sources since spatial unmasking is reduced and late reflections decrease the fidelity of the received speech signal. The latter effect could not satisfactorily be predicted by a recently presented binaural speech intelligibility model [Beutelmann et al. (2010). J. Acoust. Soc. Am. 127, 2479-2497]. This study therefore evaluated three extensions of the model to improve its predictions: (1) an extension of the speech intelligibility index based on modulation transfer functions, (2) a correction factor based on the room acoustical quantity "definition," and (3) a separation of the speech signal into useful and detrimental parts. The predictions were compared to results of two experiments in which speech reception thresholds were measured in a reverberant room in quiet and in the presence of a noise source for listeners with normal hearing. All extensions yielded better predictions than the original model when the influence of reverberation was strong, while predictions were similar for conditions with less reverberation. Although model (3) differed substantially in the assumed interaction of binaural processing and early reflections, its predictions were very similar to model (2) that achieved the best fit to the data. 相似文献
962.
Yanagisawa H Hengsberger M Leuenberger D Klöckner M Hafner C Greber T Osterwalder J 《Physical review letters》2011,107(8):087601
Energy distribution curves of laser-induced electron pulses from a tungsten tip have been measured as a function of tip voltage and laser power. Electron emission via tunneling through and/or excitation over the surface barrier from photoexcited nonequilibrium electron distributions are clearly observed. The spectral shapes largely vary with the emission processes and are strongly affected by electron dynamics. Simulations successfully reproduce the spectra, thus allowing direct insight into the involved electron dynamics and revealing the temporal tunability of electron emission via the two experimental parameters. These results should be useful to optimize the pulse characteristics for many applications based on ultrafast laser-induced electron emission. 相似文献
963.
964.
We describe two experiments in which we investigate the synchronization of coupled periodic oscillators. Each experimental system consists of two identical coupled electronic periodic oscillators that display bursts of desynchronization events similar to those observed previously in coupled chaotic systems. We measure the degree of synchronization as a function of coupling strength. In the first experiment, high-quality synchronization is achieved for all coupling strengths above a critical value. In the second experiment, no high-quality synchronization is observed. We compare our results to the predictions of the several proposed criteria for synchronization. We find that none of the criteria accurately predict the range of coupling strengths over which high-quality synchronization is observed. (c) 2000 American Institute of Physics. 相似文献
965.
Given continuous functionsu and ∈ on a closed subsetF of a Riemann surface, we seek a harmonic functionv on the surface (possibly with logarithmic singularities) such that |u−v|<∈ onF.
Research supported in part by NSERC—Canada and FCAR—Quebec. 相似文献
966.
Thomas H Pate 《Journal of Differential Equations》1979,34(2):261-272
If m and n are positive integers then let S(m, n) denote the linear space over R whose elements are the real-valued symmetric n-linear functions on Em with operations defined in the usual way. If is a function from some sphere S in Em to R then let (i)(x) denote the ith Frechet derivative of at x. In general (i)(x)∈S(m,i). In the paper “An Iterative Method for Solving Nonlinear Partial Differential Equations” [Advances in Math. 19 (1976), 245–265] Neuberger presents an iterative procedure for solving a partial differential equation of the form , where k > n, is the unknown from some sphere in Em to R, A is a linear functional on S(m, n), and F is analytic. The defect in the theory presented there was that in order to prove that the iterates converged to a solution the condition was needed. In this paper an iteration procedure that is a slight variation on Neuberger's procedure is considered. Although the condition cannot as yet be eliminated, it is shown that in a broad class of cases depending upon the nature of the functional A the restriction may be replaced by the restriction . 相似文献
967.
D. Wayne Cooke Melvin Leon Michael A. Paciotti Peter F. Meier Stephen F. J. Cox Edward A. Davis Thomas L. Estle Bassam Hitti Roger L. Lichti Carolus Boekema John Lam Anny Morrobel-Sosa Jean Oostens 《Hyperfine Interactions》1994,86(1):699-704
A distinctive longitudinal magnetic field dependence of the muon polarization for anomalous muonium in polycrystalline semiconductor targets has been predicted. The polarization exhibits a cusp,i.e., a discontinuous jump in the slope from negative to positive. Measurements of the longitudinal polarization for polycrystalline silicon in fields up to 0.5 T, and temperatures 53 and 200 K have been made at LAMPF. A cusp in the field dependence indeed occurs at 0.345 T, in excellent agreement with the prediction. No cusp is observed at 200 K because Mu* has been thermally ionized. 相似文献
968.
Thomas Höglund 《Journal of statistical physics》1988,53(3-4):825-834
A one-dimensional model is studied with nearest neighbor interaction and certain forbidden configurations. In this model it is possible to investigate the phase transition even on the microcanonical level, and it turns out that phases can coexist under certain circumstances. 相似文献
969.
The transient sound radiation from the impact of a spherical object with a slab is analysed theoretically and compared with experimental results. It is shown that the major source of sound radiation when a sphere impinges on a massive plate is due to the sudden change of velocity of the sphere. By using the method of images, an analytical expression predicting the sound pressure waveform is obtained. Experimental results confirm the theoretical analysis and provide further explanation of this rigid body type of acoustic radiation. 相似文献
970.
Thomas Kühn Mieczys?aw Masty?o 《Journal of Mathematical Analysis and Applications》2010,369(1):408-1265
We estimate Weyl numbers and eigenvalues of operators via studying their abstract summing norms. In particular we prove estimates of these summing norms for abstract interpolation Lorentz spaces. For this we combine factorization theorems with estimates of concavity constants. Finally we apply our general eigenvalue results to integral operators with kernels of weakly singular type. We obtain asymptotically optimal estimates which extend the well-known classical results. 相似文献