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1.
Traunmüller (1981) suggested that the tonotopic distance between the first formant (F 1) and the fundamental frequency (F 0) is a major determinant of perceived vowel height. In the present study, subjects identified a vowel-height continuum ranging in formant pattern from /?/ to /ε/, at fiveF 0 values. IncreasingF 0 led to an increased probability of /I/ responses (i.e., the phoneme boundary shifted toward the /ε/ end of the continuum). Various conditions of filtering out the lower harmonics of the stimuli caused only marginal shifts of the phoneme boundary. The experiments provide evidence against interpretations of Traunmüller’s (1981) results that claim that vowel height is determined by the distance betweenF 1 and the lowest harmonic that is present in the basilar membrane excitation pattern.  相似文献   

2.
The static permittivity (εm ) and the permittivity at the high-frequency limit (ε∞m ) of a binary mixture of propionic acid with tetrahydrofuran (THF) have been determined for different concentrations at temperatures of 303, 308, 313, and 318 K. The data have been used to compute the Kirkwood correlation factor, the excess permittivity, and the excess free-energy of the mixtures. The Kirkwood correlation factor is found to increase with increasing THF concentration. The mixture exhibited positive values of the excess permittivity and negative values of the excess free-energy of mixing, respectively. UV-Vis and FT-IR spectral measurements have also been carried out. The observed bathochromism and hypochromism in the UV-Vis spectra have been explained in terms of complex formation and ordering of dipoles of the complex. The FT-IR spectrum of the mixture shows considerable shifts in the positions of some of the absorption bands, indicating extensive hydrogen bonding between solute and solvent molecules.  相似文献   

3.
The directional solidification process of ternary Ag42.4Cu21.6Sb36 eutectic alloy within a wide growth rate range from 2 to 60 μm/s was accomplished at a constant temperature gradient of 50 K/cm. As growth rate increases, the ternary (θ(Cu2Sb) + ε(Ag3Sb) + Sb) eutectic morphology evolves from “lamellar (θ + ε) plus fibrous (Sb)” structure into “(θ + Sb) fibres in continuous ε matrix” structure. The θ and (Sb) phase spacings decrease with the increase of growth rate according to power functions with exponent values of 0.55 and 0.56, respectively. It is also found that the microhardness of directionally solidified Ag42.4Cu21.6Sb36 alloy samples is enhanced with the increase of growth rate, and the decrease of θ and (Sb) phase spacings.  相似文献   

4.
One of the high-temperature metastable phases found in the MgGa2O4–Ga2O3 system is the εMg non-stoichiometric Mg gallate. It has a one-dimensional periodic antiphase boundary (PAPB) structure based on the spinel structure. The APBs are parallel to the {3?1?0} planes and the APB vectors are of the 1/4?1 1 0? type when referred to the spinel structure. This generally leads to the existence of 12 monoclinic twin variants in the studied samples. By comparing the X-ray or electronic diffraction patterns of both phases, it will be shown that the recently discovered?λ?transition-alumina has the same type of structure.  相似文献   

5.
Dielectric relaxation measurements on alkyl methacrylates (methyl methacrylate, ethyl methacrylate and butyl methacrylate) with 1-alcohols (1-propanol, 1-pentanol, 1-heptanol, 1-octanol and 1-decanol) have been carried out using time-domain reflectometry (TDR) over the frequency range 10?MHz to 20?GHz at 303?K for different concentrations of alcohols. The dielectric parameters, namely the static dielectric constant (ε 0), the dielectric constant at microwave frequencies (ε ) and the relaxation time (τ) were determined. The Kirkwood correlation factor, which contains information regarding solute–solvent interaction and corresponding structural information, the excess permittivity and the excess inverse relaxation time were also determined. The values of the static dielectric constant and the relaxation time increase with the percentage of alkyl methacrylates in the alcohol, whereas the static dielectric constant decreases and the relaxation time increases with an increase in the alkyl chain length of both the methacrylates and the alcohols.  相似文献   

6.
Three experiments investigated whether extrinsic vowel normalization takes place largely at a categorical or a precategorical level of processing. Traditional vowel normalization effects in categorization were replicated in Experiment 1: Vowels taken from an [?]–[ε] continuum were more often interpreted as /?/ (which has a low first formant, F 1) when the vowels were heard in contexts that had a raised F 1 than when the contexts had a lowered F 1. This was established with contexts that consisted of only two syllables. These short contexts were necessary for Experiment 2, a discrimination task that encouraged listeners to focus on the perceptual properties of vowels at a precategorical level. Vowel normalization was again found: Ambiguous vowels were more easily discriminated from an endpoint [ε] than from an endpoint [?] in a high-F 1 context, whereas the opposite was true in a low-F 1 context. Experiment 3 measured discriminability between pairs of steps along the [?]–[ε] continuum. Contextual influences were again found, but without discrimination peaks, contrary to what was predicted from the same participants’ categorization behavior. Extrinsic vowel normalization therefore appears to be a process that takes place at least in part at a precategorical processing level.  相似文献   

7.
Oxoborates have both dielectric and magnetic properties useful for magnetodielectric devices, sensors, or biological tools. Such compounds Fe2BO4, Fe3BO5, or Fe3BO6 are known to grow easily as single crystals in a liquid flux. A polycrystalline phase forms only on controlled conditions of a solid state reaction of the basic oxides. In this study, we report highly dielectric Fe3BO6 when grown in a specific shape of nanorods (~200?nm diameter and 50–100?µm length) from an iron borate glass, which offers devisable shapes of sheets, discs, and fibers. Frequency (f)-temperature reliant dynamics of dielectric constant εr is studied over 25–300°C at 0.1–103?kHz frequencies. At low frequency such as 100?Hz, a large εr -value 40,000, better than most of high εr -value ferroelectrics, incurs at room temperature. At f?≥?50?kHz, although only an order of diminished εr -value lasts, it increases steadily with temperature, possibly due to increasing electrical conductivity in a specific resistor–capacitor network. Suppressed dielectric relaxation and spin-flops share a merely weak spin-reorientation transition near 160°C. A stable power loss ≤0.5 lasts at f?>?10?kHz useful for possible applications of magnetodielectric materials.  相似文献   

8.
Abstract

New electron spin resonance (ESR) lines with g1 = 2·0017 and g2 and g3 = 2·0006 have been found in the ESR spectra of as-deposited a-Si1–x Cx:H films prepared by magnetron sputtering of silicon in the gas mixtures of methane and argon. Similarities between the observed spectra and those for the E′ centre in glassy SiO2 are discussed.  相似文献   

9.
Quadrature frequency resolved spectroscopy (QFRS) on green (~550 nm) upconversion photoluminescence (UCPL) of Ge–Ga–S: Er3+ glasses pumped at 975 nm revealed double-peaked spectra with long lifetime τ1 ranging from 0.2 to 2 ms and short lifetime τ2 ≈ several tens of μs. The results are analysed in terms of the transfer function derived by linearizing rate equations for a three-level model. The τ1 component is attributed to the relaxation at the intermediate level 4I11/2 of Er3+ ions and the τ2 component, to that at the upper 4S3/2 manifold. The dominance of energy transfer upconversion over excited state absorption in the UCPL manifest itself as a greater dependence of τ1 on the pump power and a lower ratio of the components of τ2 to τ1 in the QFRS spectra of a heavily Er-doped sample.  相似文献   

10.
Abstract

The experimental Lα1,2 and Lβ1 X-ray emission spectra of Zn, Ga and Ge are presented. The high-energy satellite structure of the lines is considered. It appears that the intensity of these satellites relative to the main lines is much larger for Zn than for Ga and Ge. This enhancement effect is interpreted as arising mainly from the 2p?1 1/2 → 2p?1 3/23d?1 3/2,5/2 Coster-Kronig transition occurring in metallic Zn, which is absent in the case of Ga and Ge. Furthermore, for all these elements it is suggested that a significant contribution to the high-energy satellites of the Lα1,2; X-ray emission band arises from the 2s?1 1/2 → 2p?1 3/23d?1 3/2,5/2 Coster-Kronig process, whereas in the case of the satellites of the Lβ1 X-ray emission spectrum the main cause would be the 2s?1 1/2 → 2p?1 1/23d?1 3/2,5/2transition.  相似文献   

11.
A spectroscopic characterization of Er3+-doped SrAl2O4 phosphor materials synthesized by a solid-state reaction method with Er concentrations varying from 0.1 to 1?mol% has been performed by studying photoluminescence (PL) in the temperature range 10 to 360?K and absorption spectra. PL signals containing five emission bands at 1492, 1529, 1541, 1558, and 1600?nm, respectively, have been observed at room temperature for Er3+ transitions in the near infrared region. The samples exhibit a main luminescence peak at 1.54?µm, which is assigned to recombination via an intra-4f Er3+ transition. Sharp bands centered at around 378, 488, 521, 651, 980, 1492, and 1538?nm in the absorption spectra can be associated with transitions from 4I15/2 level to 2H9/2, 4F7/2, 2H11/2, 4F9/2, 4I11/2, 2H11/2, and 4I13/2 levels, respectively. The sharp emission peaks and excellent luminescence properties show that SrAl2O4 is a suitable host for rare-earth-doped phosphors, which may be suitable for optical applications.  相似文献   

12.
Hilbert's ε-calculus is based on an extension of the language of predicate logic by a term-forming operator e x . Two fundamental results about the ε-calculus, the first and second epsilon theorem, play a rôle similar to that which the cut-elimination theorem plays in sequent calculus. In particular, Herbrand's Theorem is a consequence of the epsilon theorems. The paper investigates the epsilon theorems and the complexity of the elimination procedure underlying their proof, as well as the length of Herbrand disjunctions of existential theorems obtained by this elimination procedure.  相似文献   

13.
Rare-earth (RE) elements are helpful in improving the mechanical properties of cemented carbides. In this work, the formation of Y2O3 in functionally graded cemented carbides is investigated using transmission electron microscopy. The results indicate that Y2O3 can stabilize the Co phase with the face-centred cubic structure (α-Co), since it has a cubic structure similar to the high-temperature Co phase. The α-Co phase has a higher plasticity than ε-Co, and this suggests a possible mechanism for the role of RE elements in toughening cemented carbides.  相似文献   

14.
The electric-field enhancement of hopping conductivity in amorphous solids can be described in terms of an effective temperature T eff given by for hopping, at a temperature T and field F, within a uniform distribution of electronic states with localization length γ?1. We have derived this expression analytically and find at low fields a value for C of 1/21/2, which is consistent with the F-independent value C = 0.67 previously obtained numerically for band-tail hopping. With increasing electric field, the decrease in C(F) matches the hopping transport characteristics in amorphous semiconductors (hydrogenated amorphous silicon and hydrogenated amorphous carbon nitride) better than previous numerical simulations.  相似文献   

15.
Professor Ryszard Wójcicki once asked whether the degree of maximality of the consequence operationC determined by the theorems of the intuitionistic propositional logic and the detachment rule for the implication connective is equal to \(2^{2^\aleph 0} \) ? The aim of the present paper is to give the affirmative answer to the question. More exactly, it is proved here that the degree of maximality ofC Ψ — theΨ — fragment ofC, is equal to \(2^{2^\aleph 0} \) , for every such that → εΨ.  相似文献   

16.
Theoretical calculations of the optical absorption and electron paramagnetic resonance (EPR) spectra of VO2+ in NaHC2O4?·?H2O single crystals were performed using the complete diagonalization energy matrix method (CDM) and the perturbation theory method (PTM) for the 3d 1 electronic configuration. The calculated results are in good agreement with experimental results. The negative signs of hyperfine structure constants A and A for VO2+ in NaHC2O4·H2O single crystals are suggested from the calculations. Comparison of the two calculation methods indicates that the PTM is a good approximation of CDM and that both theoretical methods are valid in interpretation of the optical and EPR spectra for VO2+ ions in NaHC2O4?·?H2O crystals.  相似文献   

17.
If ≥r and ≥d are two quaternary relations on an arbitrary set A, a ratio/difference representation for ≥r and ≥d is defined to be a function f that represents ≥r as an ordering of numerical ratios and ≥d as an ordering of numerical differences. Krantz, Luce, Suppes and Tversky (1971, Foundations of Measurement. New York, Academic Press) proposed an axiomatization of the ratio/difference representation, but their axiomatization contains an error. After describing a counterexample to their axiomatization, Theorem 1 of the present article shows that it actually implies a weaker result: if ≥r and ≥d are two quaternary retations satisfying the axiomatization proposed by Krantz et al. (1971), and if ≥r′ and ≥d′ are the relations that are inverse to ≥r and ≥d, respectively, then either there exists a ratio/difference representation for ≥r and ≥d, or there exists a ratio/difference representation for ≥r′ and ≥d′, but not both. Theorem 2 identifies a new condition which, when added to the axioms of Krantz et al. (1971), yields the existence of a ratio/difference representation for relations ≥r and ≥d.  相似文献   

18.
Research on institutional betrayal has found that institutional wrongdoing that fails to prevent or respond supportively to victims of abuse adds to the burden of trauma. In this two-study investigation with young adult university students, we demonstrated parallels between institutional betrayal and ways that families can fail to prevent or respond supportively to child abuse perpetrated by a trusted other, a phenomenon we call family betrayal (FB). In Study 1, psychometric analysis of a new FB questionnaire provided evidence of its internal consistency, unidimensionality, and convergent and discriminant validity. The majority (approximately 72%) of young adults abused in childhood reported a history of FB, with an average of 4.26 FB events (SD = 4.45, range 0–14). Consistent with betrayal trauma theory, Study 2 revealed that FB was 4× more likely to occur in relation to childhood abuse by someone very close to the victim (vs. non-interpersonal victimization), with a particularly strong effect for female participants. FB history predicted significant delay to disclosure of a self-identified worst traumatic event (ηp2 = .017) and significant increases in dissociation (?R2 = .05) and posttraumatic stress (?R2 = .07) symptoms in young adulthood. Moreover, with FB in the regression models, only FB—not child abuse nor recent interpersonal victimization—predicted dissociation and clinically significant elevations in posttraumatic stress. Findings suggest that FB is a prevalent phenomenon among young adults abused as children and that it explains unique, clinically significant variance in posttraumatic distress, warranting increased attention from trauma researchers and clinicians.  相似文献   

19.
A complete diagonalization energy matrix method (CDM) is proposed for 3d 8 ions in orthorhombic site (D 2 h ) symmetry. As an application, the optical spectra of XF2 : Ni2+ (X = Mg, Zn) is well explained on the basis of both the CDM and the semi-self-consistent field d-orbital (semi-SCF d-orbital) theory. In addition, by establishing the relationship between the optical spectra and local structure, it has been possible to calculate the crystal structure parameters for XF2:Ni2+ from optical measurements on Ni2+ ions. The theoretical results are in good agreement with experimental findings.  相似文献   

20.
Texture development during multi-step cross rolling of a dual-phase Fe–Cr–Ni alloy has been investigated. X-ray diffraction was used to investigate changes in crystallographic texture of both the constituent phases (austenite and ferrite) through changes in orientation distribution function. After deformation, rotated brass (rotated along φ1, i.e. the sample normal direction ND), along with a weak cube texture was observed in austenite, while a strong rotated cube texture was obtained in ferrite. Texture was also simulated for various strains using a co-deformation model by self-consistent visco-plastic (VPSC) formulation. Simulations showed strong rotated brass texture in austenite and a strongly rotated cube, α-fibre (sample rolling direction RD //<1 1 0>) and γ-fibre (ND //<1 1 1>) in ferrite after highest strain (εt = 1.6). VPSC models could not effectively capture the change in crystallographic texture during cross rolling. In ferrite, simulations showed an overestimation of γ-fibre component and an underestimation of rotated cube component. Simulated texture of austenite, on the other hand, showed an overestimation of rotated brass with an absence of cube component. The results are rationalised based on the possible role of shear banding and activation of non-octahedral slip system during cross rolling, both of which are not incorporated in conventional VPSC models.  相似文献   

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