Perceptual compensation for effects of reverberation in speech identification

Listeners were asked to identify modified recordings of the words "sir" and "stir," which were spoken by an adult male British-English speaker. Steps along a continuum between the words were obtained by a pointwise interpolation of their temporal-envelopes. These test words were embedded in a longer "context" utterance, and played with different amounts of reverberation. Increasing only the test-word's reverberation shifts the listener's category boundary so that more "sir"-identifications are made. This effect reduces when the context's reverberation is also increased, indicating perceptual compensation that is informed by the context. Experiment 1 finds that compensation is more prominent in rapid speech, that it varies between rooms, that it is more prominent when the test-word's reverberation is high, and that it increases with the context's reverberation. Further experiments show that compensation persists when the room is switched between the context and the test word, when presentation is monaural, and when the context is reversed. However, compensation reduces when the context's reverberation pattern is reversed, as well as when noise-versions of the context are used. "Tails" that reverberation introduces at the ends of sounds and at spectral transitions may inform the compensation mechanism about the amount of reflected sound in the signal.     

PIV Measurements of side-cavity open-channel flows —Wando model in rivers—

PIV measurements in side-cavity open-channel flows that simulate “Wando” in rivers, were conducted in a laboratory flume. Five types of side cavities were built by using a transparent plate at the wando flow. The pattern of the instantaneous flow fields was quite different from that of time-averaged ones. It was found that a vortex, which is located in the side cavity, is stable when the junction mouth between the side-cavity and main channel is narrow. In contrast, large-scale unstable vortices are generated semi-periodically when the junction mouth is wide. The free-surface fluctuations in and outside the wando were also measured by three sets of supersonic wave gauges. The amplitude of the watersurface fluctuations is large when the junction mouth is wide as compared with when its mouth is narrow. When the elevation of the free surface in the side-cavity is rising, its elevation in the main channel is falling, and vice versa when the junction mouth is wide.     

Study of characteristics of ultrasound pulse generated by a laser pulse

I.IntroductionThegenerationofacousticpulsebylaserirradiationofametalsurfacewasfirstsuggestcdbyWhitein1963[1l.SincethatdateLaserU1trasoundtechniquchasbeendcvclopedrapidly.Becausethistechniquehasanumberoftechnicalfcatures,suchasnon-contact,highbandwidth,highhme-spacia1resolution,quantitativeteshng,generationoflongitudinal,shcarandRay1cighwaves(simu1taniously),andsoon,ithasbccnwidelyapp1icdtomcasurementsofmatcrialproperties,detectionofdefects,andcalibrationoftransd.ccrsl'-'o].Inordertodcve1opth…     

Oscillating edge-flames

It has been known for some years that when a near-limit flame spreads over a liquid pool of fuel, the edge of the flame can oscillate. It is also known that when a near-asphyxiated candle-flame burns in zero gravity, the edge of the (hemispherical) flame can oscillate violently prior to extinction. We propose that these oscillations are nothing more than a manifestation of the large Lewis number instability well known in chemical reactor studies and in combustion studies, one that is exacerbated by heat losses. As evidence of this we examine an edge-flame confined within a fuel-supply boundary and an oxygen-supply boundary, anchored by a discontinuity in data at the fuel-supply boundary. We show that when the Lewis number of the fuel is 2, and the Lewis number of the oxidizer is 1, oscillations of the edge occur when the Damköhler number is reduced below a critical value. During a single oscillation period there is a short premixed propagation stage and a long diffusion stage, behaviour that has been observed in flame spread experiments. Oscillations do not occur when both Lewis numbers are equal to 1.     

Quasi-ballistic electron transport in quantum wires

Electron transport in a three-dimensional quantum wire is analyzed by taking into account electron scattering by a single point impurity. It is shown that the magnetoconductance plotted versus chemical potential μ has narrow peaks and closely located peaks separated by a dip when the scattering length is positive and negative, respectively. The peaks lie near the conductance steps. The thermopower plotted versus μ has narrow peaks and closely located peaks separated by a dip when the scattering length is positive and negative, respectively.     

Phase singularities and coherence vortices in linear optical systems

It is demonstrated for a time-invariant linear optical system that there exists a definite connection between the optical vortices (phase singularities of the field amplitude) which appear when it is illuminated by spatially coherent light and the coherence vortices (phase singularities of the field correlation function) which appear when it is illuminated by partially coherent light. Optical vortices are shown to evolve into coherence vortices when the state of coherence of the field is decreased. Examples of the connection are given. Furthermore, the generic behavior of coherence vortices in linear optical systems is described.     

Design of a solar concentrator combining paraboloidal and hyperbolic mirrors using ray tracing method

A solar concentrator combining primary paraboloidal and secondary hyperboloidal mirrors is numerically designed by using the ray tracing method to obtain higher concentration ratio when the concentrator tracing error exists. It is found that, when the concentrator tracing errors are 0.5° or 1°, the concentration ratios are about 2027 or 1220 without the detector in the radial-direction, and the concentration ratios are about 5447 or 4701 with the detector in the radial-direction. It is shown that such method can increase the concentration solar flux by two folds when the concentrator tracing error exists. Obviously, it is an effective method to reduce the effect of concentrator tracing error even when the angle of concentrator tracing error is considered. In addition, when the angle of concentrator tracing error is small than 1°, a set of mirror shapes is suggested where the primary mirror has a f-number of 0.22 and the secondary mirror has a numerical aperture (NA) of 0.61.     

Mechanoelectrical transformations upon the elastic impact excitation of composite dielectric materials

The elastic impact excitation of dielectric materials leads to an ac electromagnetic field that is a superposition of the following several fields: the field appearing when a striker approaches a surface with an excess surface charge, a field induced by electrification processes when a striker is in contact with a material surface, the field created by a shift in the acoustic wave of charges at internal inhomogeneities, the field appearing upon acoustic surface-charge oscillations, and the field that is induced in piezoactive heterogeneous materials by the piezoelectric effect.     

A hydrodynamic model for diamagnetic induced currents in molecules

The current set up when a single bound electron moves in a magnetic field obeys simple hydrodynamic equations, which arise from a variational principle. When the ground state is not degenerate they have a unique solution, determined by the unperturbed electron density. The theory is closely related to Wick's irrotational flow model for the currents in a rotating molecule, to Tillieu and Guy's variational method, and London and Rebane's ideas of gauge invariance. Difficulties arise when there is more than one electron, when the wave function has nodes, or when it is degenerate; but the method may be useful for calculating magnetic properties of some small molecules.     

Transform information: A symmetry breaking measure

A connection between two fundamental concepts of information and symmetry breaking (SB) is established. A concept called transform information (TI) is introduced. The known information measures (Hartley, von Neumann-Shannon-Wiener, Fisher informations, Renyi entropies) can be derived as (or mathematically expressed by) the particular forms of TI for certain transforms of a physical systems (when they are described by the probability measures). As TI is zero when the system is invariant under respective transform, it can be considered, when nonzero, as a quantitative SB measure in the system under study. The classical information measures that are derived from TI also can be perceived as SB measures. This fact is a base for assigning a sense to information. The concept of TI is extended to the cases when systems are described without the use of probability concept.     

Jets

This is a discussion of concentrated large-scale flows in planetary atmospheres and oceans, argued from the viewpoint of basic geophysical fluid dynamics. We give several elementary examples in which these flows form jets on rotating spheres. Jet formation occurs under a variety of circumstances: when flows driven by external stress have a rigid boundary which can balance the Coriolis force, and at which further concentration can be caused by the beta effect; when there are singular lines like the line of vanishing windstress or windstress-curl, or the Equator; when compact sources of momentum, heat or mass radiate jet-like beta plumes along latitude circles; when random external stirring of the fluid becomes organized by the beta effect into jets; when internal instability of the mass field generates zonal flow which then is concentrated into jets; when bottom topographic obstacles radiate jets, and when frontogenesis leads to shallow jet formation. Essential to the process of jet formation in stratified fluids is the baroclinic life cycle described in geostrophic turbulence studies; there, conversion from potential to kinetic energy generates eddy motions, and these convert to quasibarotropic motions which then radiate and induce jet-like large-scale circulation. Ideas of potential vorticity stirring by eddies generalize the notion of Rossby-wave radiation, showing how jets embedded in an ambient potential vorticity gradient (typically due to the spherical geometry of the rotating planet) gain eastward momentum while promoting broader, weaker westward circulation. Homogenization of potential vorticity is an important limit point, which many geophysical circulations achieve. This well-mixed state is found in subdomains of the terrestrial midlatitude oceans, the high-latitude circumpolar ocean, and episodically in the middle atmosphere. Homogenization expels potential vorticity gradients vertically to the top and bottom of the fluid, and sideways to the edges of flow domains or gyres; in both these ways is jet formation enhanced.     

Local Higgs-Kibble type theories in the unitary gauge

A general formal foundation of local theories using the Higgs-Kibble mechanism is given in the unitary gauge. The general term that is added to the Lagrangian owing to the presence of a gauge group is found both when the gauge group has and has not a non-trivial unbroken subgroup. The conjecture made by Weinberg about the form of this term when there is a non-trivial unbroken subgroup is found to be false in general. However when the unbroken subgroup is Abelian the conjecture is shown to be correct.     

Dynamic exchange coupling in magnetic bilayers

A long-range dynamic interaction between ferromagnetic films separated by normal-metal spacers is reported, which is communicated by nonequilibrium spin currents. It is measured by ferromagnetic resonance and explained by an adiabatic spin-pump theory. In such a resonance the spin-pump mechanism of spatially separated magnetic moments leads to an appreciable increase in the resonant linewidth when the resonance fields are well apart, and results in a dramatic linewidth narrowing when the resonant fields approach each other.     

57Fe Mössbauer study of La0.67Ca0.33Mn1 − x Fe x O3 CMR system

The structural changes of near-equiatomic α-FeCr alloys, ground in a vibratory mill in vacuum and in argon, were followed as a function of milling time. An amorphous phase forms in both cases but at a much faster rate when milling in argon than when milling in vacuum. Amorphisation by ball-milling of α-FeCr alloys is deduced to be an intrinsic phenomenon which is however speeded-up by oxygen. The amorphous phase crystallizes into a bcc Cr-rich phase and a bcc Fe-rich phase when annealed for short times.     

Correlation of speckle patterns generated by laser point source — Illuminated diffusers

In this paper it is shown that, when a ground-glass transilluminated by a diverging or converging beam is axially translated, there exists a particular plane in which the corresponding speckle pattern remains correlated. Consequently, under some experimental conditions on this incident beam and the geometry of the optical setup, a speckle pattern generated by a set of two parallel ground-glasses suffers no decorrelation when one of them is axially or laterally translated.     

高密度光盘径向倾斜对DPD循轨误差信号影响分析

根据高密度光盘参数 ,计算了聚焦光斑在光盘表面扫描过程中每个位置的光瞳光强分布 ,得到DPD(Differ entialPhaseDetection)循轨误差信号。考虑盘片的径向倾斜 ,在光瞳光强分布方程中引入盘片的径向倾斜角度参数 ,计算了高密度盘片产生径向倾斜时DPD循轨误差信号的变化 ,进而分析了盘片的径向倾斜引入的循轨伺服误差及其对循轨伺服的负面影响。结果表明 ,高密度盘片产生 0 .5°的径向倾斜相当于引入了 0 .0 12 μm的循轨误差     

Modulation of the secondary Bjerknes force in multi-bubble systems

The behaviours of insonated bubble clusters are regulated by the secondary Bjerknes force between bubble pairs. While the force has been investigated extensively for two-bubble systems, the modulation of the force by nearby bubbles remains unclear. This problem is investigated in this paper by theoretical analyses and numerical simulations of a three bubble system. For weak oscillations, the third bubble is found to have strong effects when its radius is close to the resonant radius. The equilibrium distance between the bubble pair is reduced when the radius of the third bubble is smaller than the resonant threshold, and increased when it is larger. For strong oscillations of bubbles with radii of a few microns, the third bubble reduces the magnitude of the force, hence increasing the equilibrium distance. The modulation effects depend strongly on the relative sizes of the bubbles. Stronger effects can be produced when the third bubble is placed closer to the smaller bubble in the bubble pair. The findings highlight the need for a more accurate parametrization of the secondary Bjerknes force in the simulation and manipulation of bubble clusters.     

非相干耦合的亮和暗光伏空间孤子对的偏转特性

采用数值方法研究了在一个具有扩散效应的光伏光折变晶体中的非相干耦合的亮和暗光伏空间孤子对的偏转特性.结果表明,由于非相干相互作用,晶体中的一个亮孤子和一个暗孤子互相俘获,且两个孤子的中心沿着相同的轨迹移动.发现,当亮孤子的入射峰值强度不变时,通过调节暗孤子的入射背景强度可以控制亮孤子的偏转;当暗孤子的入射背景强度处于一个特殊值时,亮孤子的偏转被抑制,而当暗孤子的入射背景强度偏离这个特殊值时,亮孤子发生偏转.同样,当暗孤子的入射背景强度不变时,其偏转可以通过调节亮孤子的入射峰值强度来控制.     

Random Walk Quantum Clustering Algorithm Based on Space

In the random quantum walk, which is a quantum simulation of the classical walk, data points interacted when selecting the appropriate walk strategy by taking advantage of quantum-entanglement features; thus, the results obtained when the quantum walk is used are different from those when the classical walk is adopted. A new quantum walk clustering algorithm based on space is proposed by applying the quantum walk to clustering analysis. In this algorithm, data points are viewed as walking participants, and similar data points are clustered using the walk function in the pay-off matrix according to a certain rule. The walk process is simplified by implementing a space-combining rule. The proposed algorithm is validated by a simulation test and is proved superior to existing clustering algorithms, namely, Kmeans, PCA + Kmeans, and LDA-Km. The effects of some of the parameters in the proposed algorithm on its performance are also analyzed and discussed. Specific suggestions are provided.     

多光束叠加方法对Lyot改进型退偏器的偏振相关性研究

为深入研究Lyot改进型退偏器的性能,首次利用多光束叠加方法,分析其退偏性能的偏振相关性。理论分析发现:在楔角足够大的情况下,线偏振光振动方向与入射端晶体光轴夹角,即振动方位角为0°或90°时,退偏效果理想,夹角为45°时一般最差,但当退偏器对入射波长相当于1/4波片时,任意方位角的入射光都有同样好的退偏效果。实验较好验证了理论分析结果,并通过改变入射角使样品的总延迟量达到1/4波片效果,此时退偏度在99%以上。该研究为退偏器的理论分析和设计提供了新的参考依据。