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1.
未知耦合腔体积活塞发声器声压级的检测   总被引:2,自引:0,他引:2       下载免费PDF全文
张明铎 《应用声学》2002,21(6):28-31,35
本文简要介绍了活塞发声器的工作原理及其声压级的测量原理,着重分析了未知耦合腔体积活塞发声器的有效体积与声压级的测量方法。  相似文献
2.
论声压级平均算法   总被引:2,自引:0,他引:2       下载免费PDF全文
钟恭良 《应用声学》2009,28(3):174-176
本文阐述了求声压级平均值的几种算法,特别论述了对声压级数据直接进行算术平均的运算方法。  相似文献
3.
The fundamental frequency (F0) for the habitual pitch (F0HAB), F0 for the lowest physiological tone (F0L), F0 for the highest physiological tone (F0H), F0 range of phonation (F0 Rg), sound pressure level (SPL) for habitual loudness (SPLHAB), SPL for the softest tone (SPLS), SPL for the loudest tone (SPLL), and SPL range of phonation (SPL Rg) were measured in 40 normal adult subjects and 1,563 voice patients with varying diseases. F0H, F0 Rg, SPLL, and SPL Rg were decreased in many disease groups. F0HAB and F0L varied. SPLHAB and SPLS were increased in some disease groups. F0-related parameters reflected effects of treatments in the cases with polyp, Reinke's edema, epithelial hyperplasia, carcinoma, and paralysis. Effects of treatments were manifested in SPL-related parameters in the cases with nodule, polyp, carcinoma, and paralysis.  相似文献
4.
A phonetogram is a graph showing the sound pressure level (SPL) of softest and loudest phonation over the entire fundamental frequency range of a voice. A physiological interpretation of a phonetogram is facilitated if the SPL is measured with a flat frequency curve and if the vowel /a/ is used. It was found that in soft phonation, the SPL is mainly dependent on the amplitude of the fundamental, while in loud phonation, the SPL is mainly determined by overtones. The short-term SPL variation, i.e., the level variation within a tone, was about 5 dB in soft phonation and close to 2 dB in loud phonation. For two normal voices the long-term SPL variation, calculated as the mean standard deviation of SPL for day-to-day variation, was found to be between 2.4 and 3.4 dB in soft and loud phonation. Speakers who raise their loudness of phonation also tend to raise their mean voice fundamental frequency. Measures obtained from speaking at various voice levels were combined so that typical pathways could be introduced into the phonetogram. The average slope of these pathways was 0.3–0.5 st/dB for healthy subjects. Averaged phonetograms for male singers and male nonsingers did not differ significantly, but averaged phonetograms for female singers and female nonsingers did, in that the upper contour was higher for the female singers. Averaged phonetograms for female patients with non-organic dysphonia showed significantly lower SPL values in loudest phonation as compared to healthy female subjects, while no corresponding difference was seen for males in this regard. With respect to the SPL values for softest phonation, male dysphonic patients showed significantly higher SPL values than healthy male subjects, while no corresponding difference was seen in female subjects. The subglottal pressure mirrored these phonetogram differences between healthy and pathological voices. The averaged phonetograms of female patients after voice therapy showed an increased similarity with those of normal voices. For the male patients the averaged phonetogram did not change significantly after therapy.  相似文献
5.
A noninvasive pressure-flow technique was used to assess laryngeal airway resistance (Rlaw) in eight young adult women and seven men. Syllable structures used were consonant-vowel (/pi/) and consonant-vowel-consonant (/bip/). The data were obtained from oscillographic records of intraoral air pressure and transglottal airflow over 2 consecutive days. Repetitions of each syllable context were produced at each subject's 25th, 50th, and 75th percentiles of vocal sound pressure level. No significant differences in Rlaw were found across days for the two groups. Women had significantly greater Rlaw than did men for the /pi/ and /bip/ contexts. Men showed a significantly greater average airflow rate than did women for both syllable contexts. Airflow, air pressure, and the ratio Rlaw increased as the sound pressure level of voice increased. The technique appears to be useful for characterizing certain features of laryngeal airway resistance for men and women.  相似文献
6.
Professional vocalists encounter demands requiring voluntary control of phonation, while utilizing a considerable range of frequency and intensity. These quantifiable acoustic events can be measured and represented in a phonetogram. Previous research has compared the phonetograms of trained and untrained voices and found significant differences between these groups. This study was designed to assess the effects of vocal training for singers over a period of nine months. Phonetogram contour changes were examined, with the primary focus on expansion of frequency range and/or intensity control. Twenty-one first-year, master's level, vocal music students, who were engaged in an intensive vocal performance curriculum, participated in this study. Following nine months of vocal training, significant differences were revealed in the subjects' mean frequency range and minimum vocal intensity across frequency levels. There was no significant difference for the mean maximum vocal intensity across frequency levels following vocal training.  相似文献
7.
Preschool teachers are at risk for developing voice problems such as vocal fatigue and vocal nodules. The purpose of this report was to study preschool teachers' voice use during work. Ten healthy female preschool teachers working at daycare centers (DCC) served as subjects. A binaural recording technique was used. Two microphones were placed on both sides of the subject's head, at equal distance from the mouth, and a portable DAT recorder was attached to the subject's waist. Recordings were made of a standard reading passage before work (baseline) and of spontaneous speech during work. The recording technique allowed separate analyses of the level of the background noise, and of the subjects' voice sound pressure level, mean fundamental frequency, and total phonation time. Among the results, mean background noise level for the ten DCCs was 76.1 dBA (range 73.0-78.2), which is more than 20 dB higher than what is recommended where speech communication is important (50-55 dBA). The subjects spoke on an average of 9.1 dB louder (p < 0.0001), and with higher mean fundamental frequency (247 Hz) during work as compared to the baseline (202 Hz) (p < 0.0001). Mean phonation time for the group was 17%, which was considered high. It was concluded that preschool teachers do have a highly vocally demanding profession. Important steps to reduce the vocal loading for this occupation would be to decrease the background noise levels and include pauses so that preschool teachers can rest their voices.  相似文献
8.
The effects of prolonged (5x45 minute) reading (vocal loading) on fundamental frequency (F0), sound pressure level (SPL), subglottal (intraroral) pressure (p), and two glottal flow waveform parameters (AC amplitude of glottal flow, f, and negative peak amplitude of differentiated flow (d) of normal female and male subjects (N = 80) were studied. Two rest (morning and noon) and three loading (two in the morning and one in the afternoon) samples were recorded and analyzed. The glottal waveforms were obtained by inverse filtering of the acoustic pressure waveforms of speaking voice samples. The analyses were based on measurement and inverse filtering of the first stressed syllable of "paappa" words repeated 3x5 times for normal, as soft as possible, and as loud as possible phonation. In normal phonation the parameter values changed statistically significantly due to loading. In many cases the values obtained in the morning samples changed after the first loading session. This is interpreted as a vocal "warming-up effect." Especially in soft phonation p, d, and f were sensitive indicators of vocal loading. In both normal and soft phonation, the SPL, p, d, and f values tended to rise due to prolonged reading in the morning and afternoon samples, indicating increased effort (normal phonation) and a rise in the phonatory threshold (soft phonation). The lunch break vocal rest ("rest effect") considerably affected the parameter values in many cases.  相似文献
9.
本文介绍了在近代与综合性物理实验中的一个综合性物理实验题目──室内混响时间的测量.主要说明了实验仪器、实验基本原理和方法.  相似文献
10.
Noninvasive measures of vocal fold activity are useful for describingnormal and disordered voice production. Measures of open and speed quotient from glottal airflow and electroglottographic (EGG) waveforms have been used to describe timing events associated with vocal fold vibration. To date, there has been little consistency in the measurement criteria used to calculate quotient values. In this study, criteria of 20% and 50% were applied to the AC amplitude of glottal airflow and inverted EGG waveforms for measurement of open quotient. Criteria of 20%, 50%, and 80%, and a midslope criterion that segmented the waveform between 20% and 80% of the waveform amplitude, were used for the calculation of speed quotient. Subjects produced waveforms at sound pressure levels (SPL) of 70, 75, 80 and 85 dB. Results indicated that approximations of open quotient obtained from the glottal airflow waveform significantly decreased using both the 20% and 50% criteria as SPL increased from 80 to 85 dB. No significant changes were found in open quotient from the EGG waveform as a function of SPL. Results of speed quotient measures from the glottal airflow and EGG waveforms showed a generally increasing trend as SPL increased, although the differences were not statistically significant. The data suggest that the signal type, measurement criterion and SPL must be considered in interpreting quotient measures.  相似文献
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