Some Phonatory and Resonatory Characteristics of the Rock, Pop, Soul, and Swedish Dance Band Styles of Singing

This investigation aims at describing voice function of four nonclassical styles of singing, Rock, Pop, Soul, and Swedish Dance Band. A male singer, professionally experienced in performing in these genres, sang representative tunes, both with their original lyrics and on the syllable /pae/. In addition, he sang tones in a triad pattern ranging from the pitch Bb2 to the pitch C4 on the syllable /pae/ in pressed and neutral phonation. An expert panel was successful in classifying the samples, thus suggesting that the samples were representative of the various styles. Subglottal pressure was estimated from oral pressure during the occlusion for the consonant [p]. Flow glottograms were obtained from inverse filtering. The four lowest formant frequencies differed between the styles. The mean of the subglottal pressure and the mean of the normalized amplitude quotient (NAQ), that is, the ratio between the flow pulse amplitude and the product of period and maximum flow declination rate, were plotted against the mean of fundamental frequency. In these graphs, Rock and Swedish Dance Band assumed opposite extreme positions with respect to subglottal pressure and mean phonation frequency, whereas the mean NAQ values differed less between the styles.     

Decomposition of Vocal Cycle Length Perturbations into Vocal Jitter and Vocal Microtremor, and Comparison of Their Size in Normophonic Speakers

A statistical method that enables raw vocal cycle length perturbations to be decomposed into perturbations ascribed to vocal jitter and vocal tremor is presented, together with a comparison of the size of jitter and tremor. The method is based on a time series model that splits the vocal cycle length perturbations into uncorrelated cycle-to-cycle perturbations ascribed to vocal jitter and supra-cycle perturbations ascribed to vocal tremor. The corpus was composed of 114 vocal cycle length time series for sustained vowels [a], [i], and [u] produced by 22 male and 16 female normophonic speakers. The results were the following. First, 100 out of 114 time series were decomposed successfully by means of the time series model. Second, vocal perturbations ascribed to tremor were significantly larger than perturbations ascribed to jitter. Third, the correlation between vocal jitter and vocal tremor was moderate, but statistically significant. Fourth, small but statistically significant differences were observed among the three vowel timbres in the relative jitter and the arithmetic difference of jitter and tremor. Fifth, the differences between male and female speakers were not statistically significant in the relative raw perturbations, the relative jitter, or the modulation level owing to tremor.     

Glottal airflow and electroglottographic measures of vocal function at multiple intensities

Ten normal female subjects produced syllables at 5 dB increments from soft to loud. The differentiated electroglottogram (dEGG) open and speed quotients were compared to similar quotients from the inverse-filtered airflow waveform. The latter were measured according to objective and subjective criteria. The data indicate that the open quotient from the airflow waveform decreased as the intensity increased. The dEGG open quotient did not demonstrate this trend. The speed quotient from airflow increased initially with vocal intensity and decreased again as the intensity ceiling was approached. The ratio of closing to opening slopes calculated from peaks in the dEGG signal followed a similar pattern. While the trends across intensity conditions were found to correspond for several of the measures, the absolute values obtained using the different methodologies were not comparable.     

Aerodynamic Measurements: Normative Data for Children Ages 6:0 to 10:11 Years

Normative measures of open quotient, speed quotient, maximum flow declination rate (MFDR), and subglottal pressure were determined for 75 children between the ages of 6 years 0 months and 10 years 11 months. The participants produced a sustained /a/ at low, comfort, and high pitches for a minimum of 5 seconds, and five to seven repetitions of /pa/ at low, comfort, and high pitches. No statistically significant differences were found in the mean measures of any aerodynamic variables (open quotient, speed quotient, maximum flow declination rate, subglottal pressure) between the frequency levels (low, comfort, high pitches). Also, no strong evidence (P > .05) exists that age or sex effect differed between the frequency levels (low, comfort, high) for any of the aerodynamic measures. For /a/ response tasks, mean open quotient measures increased slightly from low to comfort frequency and from comfort to high frequency. Mean speed quotient measures showed minimal differences between low and comfort frequency, with decreased mean measures for high frequency. Mean MFDR measures increased from low to comfort frequency and from comfort to high frequency. Mean subglottal pressure measures increased slightly from low to comfort frequency and from comfort to high frequency.     

Intensity range as a function of task and training

This study examined intensity range as a function of elicitation task (reading and automatic speech sequences), musical training, and the interaction between task and musical training in 31 college students. The results indicated significant differences in loudness range by experiental task. Intensity range for the descending automatic sequence was significantly greater than that for the ascending and reading tasks. While the overall effect of musical training was nonsignificant, there was a significant interaction between task and training, with musicians having a significantly greater mean range on the ascending task. A comparison between ascending and descending tasks indicated a significant mean difference between lower limits and no significant mean difference between upper limits. The range for the reading probe was located approximately in the middle of the total available intensity range.     

Oral Breathing Increases Pth and Vocal Effort by Superficial Drying of Vocal Fold Mucosa

Oral breathing superficially dehydrates the airway lumen by decreasing the depth of the sol layer in humans and animals. Conversely, nasal breathing can increase the humidity of inspired air. We compared the effects of short-term oral and nasal breathing on P_th and perceived vocal effort in 20 female subjects randomly assigned to two groups: oral breathing (N = 10, age 21–32 years); nasal breathing (N = 10, age 20–36 years). We hypothesized that short-term oral breathing, but not nasal breathing, would increase P_th, and that subjects would perceive this change as an increase in vocal effort. Following 15 minutes of oral breathing, P_th increased at comfortable and low pitch (p < 0.01) with 6 of 10 subjects reporting increased vocal effort. Nasal breathing reduced P_th at all three pitches (p < 0.01), and 7 of 10 subjects reported decreased vocal effort. Over all subjects, 49% of the variance in treatment-induced change in P_th was accounted for by change in vocal effort (R = 0.70). We posit that obligatory oral breathing places healthy subjects at risk for symptoms of increased vocal effort. The facilitatory role of superficial hydration on vocal fold oscillation should be considered in biomechanical models of phonation and in the clinical prevention of laryngeal dryness.     

Vocal loudness and frequency capabilities of the voice

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.     

Clinical Characteristics and Voice Analysis of Patients With Mutational Dysphonia: Clinical Significance of Diplophonia and Closed Quotients

The aim of this study was to investigate the acoustic and electroglottographic characteristics of patients with mutational dysphonia before and after voice therapy. The clinical records of 15 patients with mutational dysphonia were reviewed, and their voice recordings were analyzed with the help of the Lx Speech Studio program (Laryngograph Ltd, London, UK). After voice therapy combined with the manual compression method, the subjects' voices lowered in pitch and improved in quality. In addition, we classified the mutational dysphonia into four categories according to the presence of diplophonia and closed quotients. The most common type among the categories was characterized by a bimodal distribution of fundamental frequency (diplophonia), accompanied by a low closed quotient (falsetto voice) at high frequencies. However, the results also showed that mutational dysphonia cannot be generalized as always having a falsetto voice, as shown in other types. The effect of therapy was different for each type, and those cases with both diplophonia and a non-trained falsetto voice could be treated more readily. Consequently, the diplophonia and closed quotient, which were easily analyzed using Lx Speech Studio program, are important factors in the classification of mutational dysphonia. Identification of these characteristics may affect treatment choices, facilitate monitoring of the efficacy of therapy, and aid in estimating prognosis.     

磁旋光效应实验的旋光特性研究和数据分析

通过磁旋光效应(法拉第效应)实验,对不同物质的旋光特性有所认识。实验发现,磁旋光性物质具有左旋和右旋之分,而且它的旋光方向是由磁场的方向来决定。根据实验数据分析获得磁场强度与偏振角之关系,观察磁场电流与旋光方向的关系,进一步了解不同介质的旋光特性。     

高灵敏度光纤光栅压力传感器及其压力传感特性的研究

采用增敏罐封装的方法 ,设计并研究了一种新型高灵敏度的光纤光栅压力传感器 ,其压力灵敏系数可高达- 3.41× 10 - 3 MPa- 1 (相应于灵敏度 - 5 .2 77nm MPa) ,压力灵敏系数较裸光纤提高了 172 2倍 ,且线性度良好 ,可应用于低压情况下物理量的传感测量     

浆氮制备及其管内流动特性的实验研究

本文对冻结一融化法制备浆氮进行了研究,考查了真空泵抽速及冻结、融化时间对浆氮性质的影响,得到了制备含有细小固氮颗粒浆氮的方法。并研究了浆氮在内径10 mm的水平长直圆管中的流动性质。实验结果表明,当真空泵抽速大于4 L/s且冻结与融化时间分别为10 s与5 s时制备效率高且生成的固氮颗粒直径约1 mm。浆氮在水平圆管内流动时单位长度的压降略高于液相压降,且随流速和固相体积分数的增加而增加,在低速时固相体积分数对流动压降有明显影响。     

熊猫型保偏光纤光栅温度和压力传感特性的实验研究

对熊猫型保偏光纤光栅的传感特性进行了深入的实验研究,采用温箱和压力罐分别进行了温度和压力传感特性的实验研究.实验结果表明:在0～2.5 MPa的压强范围内,熊猫型保偏光纤光栅两个偏振方向上的压力敏感系数分别为0.004 88 nm/MPa和0.003 52 nm/MPa;在15～50 ℃的温度范围内,两个偏振方向上的温度敏感系数为0.01018 nm/℃和0.008 8 nm/℃.该光纤光栅两偏振态对温度和压力的不同敏感特性可用于解决光纤光栅的交叉敏感问题.     

Analogy between first-order phase transitions and blackbody radiation

The analogy between blackbody radiation and a phase equilibrium between vapor and liquid is drawn by deriving the Clapeyron equation in which the two probability distributions of blackbody radiation play the role of the two phases. The pressure of one of these distributions, which becomes negative at sufficiently high photon energies, is analogous to a negative pressure tending to break up a liquid. A similar type of critical phenomenon should be observed for blackbody radiation.     

不同卸围压速率下花岗岩的力学性质及声发射特征

为了研究不同卸围压速率下花岗岩的力学性质,利用RMT-150B岩石力学试验系统对花岗岩试样进行恒轴压卸围压应力路径试验。试验结果表明:相同的初始围压下,随着卸围压速率增大,岩样的延性减小,表现为脆性破坏。卸围压速率越大,卸围压阶段的应变率越高,但总变形量小;当卸围压的速率相同时,初始围压越高,卸围压阶段岩样的应变率和总变形量越大。采用Mogi-Coulomb强度准则对试验结果进行拟合,结果显示:卸围压速率对花岗岩的黏聚力有劣化作用,对岩石的内摩擦角有强化作用;卸围压速率越小,振铃计数的活跃期越长,表明在低卸围压速率下,花岗岩岩样内部损伤发展缓慢且完全。     

Characteristics of emission from laser-induced plasma of metallic compounds in gaseous condition: The effects of gas pressure and laser pulse energy

Low-pressure laser-induced breakdown spectroscopy (LIBS) was employed to measure mercury, strontium, and cesium under different conditions. Mercury was measured in detail to discuss the effects of pressure, laser pulse energy, delay time, and buffer gas. The continuum emission from plasma reduced dramatically to enhance signal-to-background ratio due to the change of influence of electron impact ionization process when reducing pressure and decreasing laser pulse energy to some extent. The comparison of mercuric chloride and mercury, as well as strontium and cesium measurements, demonstrates the enhancement of detection ability for trace species measurement using low-pressure LIBS.