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41.
This paper presents a bimodal (audio-visual) study of speech loudness. The same acoustic stimuli (three sustained vowels of the articulatory qualities "effort" and "noneffort") are first presented in isolation, and then simultaneously together with an appropriate optical stimulus (the speaker's face on a video screen, synchronously producing the vowels). By the method of paired comparisons (law of comparative judgment) subjective loudness differences could be represented by different intervals between scale values. By this method previous results of effort-dependent speech loudness could be verified. In the bimodal study the optical cues have a measurable effect, but the acoustic cues are still dominant. Visual cues act most effectively if they are presented naturally, i.e., if acoustic and optical effort cues vary in the same direction. The experiments provide some evidence that speech loudness can be influenced by other than acoustic variables. 相似文献
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Some distinctive features in the behavior of small-scale artificial ionospheric irregularities at mid-and high latitudes 总被引:1,自引:0,他引:1
N. F. Blagoveshchenskaya T. D. Borisova V. A. Kornienko V. L. Frolov M. T. Rietveld A. Brekke 《Radiophysics and Quantum Electronics》2007,50(8):619-632
We present the results of experimental studies of some features in the behavior of small-scale artificial irregularities (SSAIs)
at mid-and high latitudes based on the “Sura” and EISCAT/HEATING HF facilities. Observations were performed by the method
of aspect scattering using a network of diagnostic paths having a common reception point located near St. Petersburg. We found
that an extremely long duration of the second (slow) stage of SSAI relaxation of up to 5 min occurs in the evening hours when
the ionosphere above the “Sura” facility is illuminated by the Sun, but the solar terminator travels through the magnetically
conjugated ionosphere. The conjecture is made that the processes initiated by the terminator are mostly responsible for secondary
ionospheric turbulence maintaining the irregularities above “Sura.” A drastic increase in the Doppler spectra width of the
scattered signals is revealed when the magnetically conjugate point of the ionosphere is located on the shade side of the
terminator, but the ionosphere above the “Sura” facility is still lighted. It is assumed that the “ run away” of photoelectrons
from the day to the night side could reduce the threshold of excitation of artificial irregularities, leading to an increase
in their intensity. The presence of fairly intense scattered signals was detected from the “Sura” and EISCAT/HEATING experimental
results both under conditions of pulsed HF heating after continuous heater-on periods and cycled HF heating by short pulses.
In the case of pulsed heating by short pulses with duration τp < 100 ms and average radiated power Pa below the threshold power Pthr of the SSAI generation cutoff the irregularities can be maintained due only to striction parametric instabilities. The excitation
of irregularites under the cycled HF pumping with the pulse duration τp = 384 ms for Pa comparable with Pthr was detected. The aspect-angle dependence, or the so-called magnetic zenith effect, was found in the SSAI intensity. The
residual turbulence aftereffects played a significant role in the SSAI development.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 50, No. 8, pp. 678–694, August 2007. 相似文献
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This paper aims to present a newly developed distance friction minimization (DFM) method in the context of data envelopment analysis (DEA) in order to generate an appropriate (non-radial) efficiency-improving projection model, for both input reduction and output increase. In this approach, a generalized distance function, based on a Euclidean distance metric in weighted spaces, is proposed to assist a decision making unit (DMU) to improve its performance by an appropriate movement towards the efficiency frontier surface. A suitable form of multidimensional projection function for efficiency improvement is given by a Multiple Objective Quadratic Programming (MOQP) model. The paper describes the various steps involved in a systematic manner. 相似文献
48.
H. Morawitz I. Bozovic V. Z. Kresin G. Rietveld D. van der Marel 《Zeitschrift für Physik B Condensed Matter》1993,90(3):277-281
The plasmon density of states (DOS)p() of a layered electron gas (LEG) is studied theoretically. It is shown thatp() is a linear function of frequency as goes to 0, and then increases more rapidly as tends to the screened, three dimensional plasma frequency p. We also study the partial densities of state for constantK andq
z
, whereK andq
z
are the magnitude of the transverse and perpendicular momentum transfers. A possible experimental probe for the plasmon DOS is discussed. 相似文献
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Uniaxial negative thermal expansion in crystals of tienoxolol 总被引:1,自引:0,他引:1
Béatrice Nicolaï Ivo B. Rietveld Maria Barrio Nathalie Mahé Josep-Lluís Tamarit René Céolin Christophe Guéchot Jean-Marie Teulon 《Structural chemistry》2013,24(1):279-283
The thermal expansion of tienoxolol has been investigated by X-ray powder diffraction up to its melting temperature. The data indicate that the expansion is anisotropic and even negative in one direction of the unit cell. The supramolecular structure formed by hydrogen-bonds reflects that of a trellis, which explains the observed behavior of tienoxolol crystals. 相似文献