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1.
On the basis of electron Hall concentration temperature dependences in n-type silicon samples with relatively low content of oxygen (the majority impurity), it is found that divacancies are annealed through their decay, combining oxygen-stimulated dissociation with free dissociation in monovacancies. Such a mechanism is compared with direct conversion of divacancies into more complex defects by way of association with dopant atoms in p-type silicon.  相似文献   

2.
As the human ear is dull to the phase in speech, little attention has been paid to phase information in speech coding. In fact, the speech perceptual quality may be degenerated if the phase distortion is very large. The perceptual effect of the STFT (Short time Fourier transform) phase spectrum is studied by auditory subjective hearing tests. Three main conclusions are (1) If the phase information is neglected completely, the subjective quality of the reconstructed speech may be very poor; (2) Whether the neglected phase is in low frequency band or high frequency band, the difference from the original speech can be perceived by ear;(3) It is very difficult for the human ear to perceive the difference of speech quality between original speech and reconstructed speech while the phase quantization step size is shorter than π/7.  相似文献   

3.
1IntroductionXUYi[l]classifiesjuncturesofChineseinfourcategories'inner-syllablejuncture,between-syllablejuncture,rhythmjuncture,andpausejuncture.Amongthefourcategories,theinner-syllablejunctureisthestrongestone,thebetween-syllablejunctureisthesecond,andtheothertwokindsofjuncturesareweaker.SincemonosyllablesusuallyareadoptedasChinesesyntheticunits,theinner-syllablejuncturehasbeenpreservedinsyllables.Thereforetheinfiuenceofbetween-syllablejunctureonperceptionofnaturalnessofsynthesisChineseisth…  相似文献   

4.
The perceptive multi-dimension structure of Chinese syllables is studied by psychological-physical experiment. The results indicate that FO and duration are interrelated to two main dimensions of the perceptive structure of Chinese syllable. And the prosodic characteristics such as the position of syllable in prosodic hierarchical structure, as well as the stress will be induced the various distribution of syllable in perception space.  相似文献   

5.
It is difficult to establish structure-property relationships in a defective solid because of its inhomogeneous-geometry microstructure caused by defects. In the present research, the effects of pores and cracks on the Young’s modulus of a defective solid are studied. Based on the law of the conservation of energy, mathematical formulations are proposed to indicate how the shape, size, and distribution of defects affect the effective Young’s modulus. In this approach, detailed equations are illustrated to represent the shape and size of defects on the effective Young’s modulus. Different from the results obtained from the traditional empirical analyses, mixture law or statistical method, for the first time, our results from the finite element method (FEM) and strict analytical calculation show that the influence of pore radius and crack length on the effective Young’s modulus can be quantified. It is found that the longest crack in a typical microstructure of ceramic coating dominates the contribution of the effective Young’s modulus in the vertical direction of the crack.  相似文献   

6.
Both horizontal and vertical binocular disparities produce depth perception in adults. In developmental studies, infants aged around 4 to 6 months were shown to perceive depth from horizontal disparity. However, infants’ sensitivity to vertical disparity has not been shown clearly. To examine the sensitivity in infants, this study measured preferential looking behavior of infants aged 20 to 27 weeks. Results showed a significant preference for the stimulus with vertical disparity, providing the first evidence of infants’ sensitivity to vertical disparity. The infants in the same age group did not show preference for stimulus with horizontal disparity when the stimulus were comparable to the stimulus with vertical disparity, while their sensitivity to horizontal disparity was confirmed with the stimuli used in a previous study. Our results would suggest that properties in processing horizontal and vertical disparities are different in infancy, and that the sensitivity to horizontal disparity are still premature in 27 weeks after birth.  相似文献   

7.
8.
The absorption spectra of agglutinating sera were used to determine blood groups. It was shown experimentally that the sera color significantly affects the resolving power of the acousto-optical method of blood typing. In order to increase the resolving power of the method and produce an invariance of the method for sera color, we suggested introducing a probing light beam individually for different sera. The proposed technique not only improves the resolving power of the method, but also reduces the risk of false interpretation of the experimental results and, hence, error in determining the blood group of the sample. The latter is especially important for the typing of blood samples with weak agglutination of erythrocytes. This study can be used in the development of an instrument for instrumental human blood group typing based on the acousto-optical method.  相似文献   

9.
The problem of a small magnet levitating above a very thin superconducting disc in the Meissner state is analysed. The dipole-dipole interaction model is employed to derive analytical expressions for the interaction energy, levitation force, magnetic stiffness and frequency of small vibrations about the equilibrium position in two different configurations, i.e. with the magnetic moment parallel and perpendicular to the superconductor. The results show that the frequency of small vibrations decreases with the increasing levitation height for a particular radius of the superconducting disc, which is in good agreement with the experimental results. However, the frequency increases monotonically up to saturation by increasing the radius of the disc for a particular height of the magnet. In addition, the frequency of vibrations is higher when the system is in the vertical configuration than that when the system is in the horizontal configuration.  相似文献   

10.
Theoretical papers predict that prompt LII signals are weakly dependent on the soot size due to the fact that larger particles reach higher temperatures during the heating process by nanosecond laser pulses. This question is of crucial importance for establishing LII as a practical technique for soot volume fraction measurements. In this work two-color prompt LII measurements have been performed in several locations of diffusion and rich premixed ethylene-air flames. The experimental apparatus was carefully designed with a probe volume of uniform light distribution and sharp edges, a 4 ns integration time around the signal pulse peak and narrow spectral bandwidth. Measurements did not confirm the theoretical predictions concerning an increase of temperature for larger particles. On the contrary, larger particles in richer premixed flames exhibit a lower 400/700 signal ratio. This can probably be attributed to small differences in the refractive index of soot.  相似文献   

11.
A study was made of the pressure dependence of the intensity of the Mössbauer line, and the dependence of this quantity on the specific volume of the crystal, which has the same form for all these crystals in the first approximation, was derived for regular atomic crystals in the Grüneisen approximation. The change in intensity of the Mössbauer line due to pressure can be converted, except for a multiplication factor, to a change in intensity of this line caused by a change in temperature.  相似文献   

12.
1IlltroductionWiththedevelopmentofspeechsynthesistechnique,ChinesesynthesissystemhasbeendemonstratedtheabilityofsynthesizingclearandintelligibleStandardChin...[1].However,thenaturalnessofthesynthesizedspeechisnotasperfectasitisexpected[2].HowtoimprovethenaturalnessofsylltheticspeechhavedrawnmuchattentionsintheresearchofrecentStandardChinesetext-to--speechsystem.Impropercontroloftheprosodyofthesyntheticspeechisoneofthemainreasonsthatdescendthenaturalness.Soimprovingprosodicmodelisesselltialf…  相似文献   

13.
This paper,taking the distance between the piezoelectricceramic center and the displacement node location of the transducer asa parameter,investigates the relation of characteristic parameters oftransducer,such as force factor,equivalent resistance,potential maximumelectroacoustical efficiency,and loading performance,to the displacementnode location.Some design considerations about the selection of nodelocation are noted.  相似文献   

14.
Airport noise insulation programmes (NIPs) implement active measures for reducing the amount of noise to which people are exposed without impacting the operating capacity of an airport. This is the reason why they are one of the most extended actions adopted internationally by airport authorities to fight noise in airport surroundings.Beyond the assumption that a correct implementation of the NIP will significantly reduce sound exposure, this research aims to determine the efficacy of the NIP as a result of the beneficiaries’ subjective perception in terms of satisfaction, and the reduction of the reported annoyance.A telephone survey was carried out in more than 650 dwellings in the surroundings of several Spanish Airports (Alicante, Bilbao, Grand Canary, Malaga, Palma de Mallorca). The results have shown that: (a) the beneficiaries have a generally positive perception regarding the actions implemented, (b) they are quite satisfied regarding the insulation of the façades after NIP implementation, (c) they report a reduction of the annoyance, but (d) they still perceive aircraft noise as a source of disturbance.The statistical analysis of the results has also shown that there are some non-acoustic factors influencing citizens’ perception of NIPs. Factors such as the aesthetic of windows, or the reliability and professionalism of the workers and technicians involved in the NIP, have been shown to modify people’s reaction. But, the dissatisfaction with legal aspects of Spanish regulations concerning a lower protection of some practical spaces (like, bathrooms and kitchens that have been left out in many cases) has been found to be the factor most affecting people’s response.  相似文献   

15.
The values of effective breeding coefficient Keff in a reactor core of nuclear power plant are calculated for different values of parameters (core structure, fuel assembly component) by using the Monte Carlo method. The obtained values of Keff are compared and analysed, which can provide theoretical basis for reactor design.  相似文献   

16.
Because of the influence of OH groups in phosphate glasses on the radiation of rare-earth ions, the laser performance is degraded. The laser efficiency and the small signal gain experiment of several phosphate glass samples have been done, the concentration of OH groups in glasses was calculated from the measured absorption coefficient at 3.47 μm. It is shown that the concentration of OH groups in phosphate glasses can seriously influence the laser output characteristics, and the OH groups have worse influence on the laser amplifier than laser oscillator.  相似文献   

17.
The relation between the expanding universe and local vacuum solutions, such as that for the Solar System, is crucially mediated by Birkhoff’s theorem. Here we consider how that relation works, and give generalizations of Birkhoff’s theorem when there are geometric and matter and perturbations. The issue of to what degree dark matter might influence the solar system emerges as a significant question.  相似文献   

18.
19.
Hastings [12] recently provided a proof of the existence of channels which violate the additivity conjecture for minimal output entropy. In this paper we present an expanded version of Hastings’ proof. In addition to a careful elucidation of the details of the proof, we also present bounds for the minimal dimensions needed to obtain a counterexample.  相似文献   

20.
With the help of the replica method and imaginary-time functional-integrate technique, the spin glass model with the vibrations of crystal lattices is investigated. In the limit of the replica symmetry and the imaginary-time static approximation, the magnetic and thermodynamic quantities have been obtained. By the numerical calculations, we found that the magnetization of the system has the typical spin-glass behaviour. A peak is found in the susceptibility-temperature curve and is shifted to lower temperature with increasing applied field. Due to the lattice contribution, the specific heat increases strongly at high temperature.“ Due to the magnetic contribution, the anomaly in the specific heat-temperature curve forms a λ-type peak, which agrees with the observation of Rojo et al. [Phys. Rev. B 66 (2002) 094406].  相似文献   

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