Qualitative and quantitative analysis of voice onset by means of a multidimensional voice analysis system (MVAS) using high-speed imaging

High-speed filming is one of the most informative methods for assessing voice physiology data. Tracing high-speed images of the glottis provides quantitative parameters such as the glottal area and the glottal width function. By way of example, a number of studies are discussed which extract quantitative data from high-speed images showing voice onsets. Furthermore, a new computer system (MVAS; multi-dimensional voice analysis system) is presented that synchronously displays a laryngoscopic high-speed film, the electroglottographical signal, and several acoustic analyses of the recorded voice sample. The automatic measurement of glottal width and glottal area from the laryngoscopic images is also provided. Looking at former studies and our analyses of voice onsets reveals a tremendous intersubject and even intrasubject variability (different prephonatory closure, different time span until full amplitude is reached, different open quotient).     

The membranous contact quotient: A new phonatory measure of glottal competence

The membranous contact quotient (MCQ) is introduced as a measure of dynamic glottal competence. It is defined as the ratio of the membranous contact glottis (the anterior-posterior length of contact between the two membranous vocal folds) and the membranous vocal fold length. An elliptical approximation to the vocal fold contour during phonation was used to predict MCQ values as a function of vocal process gap (adduction), maximum glottal width, and membranous glottal length. MCQ is highly dependent on the vocal process gap and the maximum glottal width, but not on vocal fold length. Five excised larynges were used to obtain MCQ data for a wide range of vocal process gaps and maximum glottal widths. Predicted and measured MCQ values had a correlation of 0.93, with an average absolute difference of 9.6% (SD = 10.5%). The model is better at higher values of MCQ. The theory for MCQ is also expressed as a function of vocal process gap and subglottal pressure to suggest production control potential. The MCQ measure is obtainable with the use of stroboscopy and appears to be a potentially useful clinical measure.     

An experimental study of the effect of the blow-in rate on the size of the flow separation region

Experimental results are presented concerning the effect of the air blow-in rate on the size of the flow separation region downstream of a rearward-facing step at different step heights. The stream function is found from the experimental velocity profiles, the streamline = 0 being taken as the boundary line. It is shown that the separation region increases as the blow-in rate is increased. Generalization of the experimental results for different blow-in rates and step heights has made it possible to obtain an analytical expression describing the location of some characteristic lines in the separation region (boundary streamline, reverse-flow boundary, line of reverse-flow maximum velocity, line of variable-velocity layer thickness, and the displacement thickness line). Velocity profiles are obtained by means of a hot-wire anemometer. Analytical expressions are written as polynomials with unknown coefficients. The results obtained may be helpful in developing techniques for the treatment of heat transfer under flow separation conditions.     

送风方式对飞机座舱内污染物传播影响研究

采用数值模拟方法研究了波音737-200座舱模型内的气流场以及污染物传播过程,并通过实验数据加以验证;分析了天花板加侧壁送风(混合送风)、侧壁送风以及天花板送风三种送风方式下座舱内的速度场、涡量场、污染物浓度场和空气龄,并且解释了舱内流场结构对污染物传播过程的影响。研究结果表明:不同送风方式下飞机座舱内污染物的传播过程差异明显,这是由流场结构特征的差异造成的,特别是在小尺度范围内,涡结构十分复杂,严重影响污染物的传播规律;在聚集过程中,污染物更容易在漩涡范围内聚集,而变形主导的气流运动会阻碍污染物向更大范围传播;在排除过程中,天花板送风形式下污染物的排除效率最快,混合送风次之,侧壁送风最慢。这对于防控新冠肺炎是有参考价值的。     

Pushing exercise program to correct glottal incompetence

A voice therapy program using pushing exercises to correct glottal incompetence is described. The program utilizes various types of instrumentation to determine whether or not a given patient is likely to benefit from the treatment. The program also provides feedback of target voices. Three cases with incomplete glottal closure and subsequent vocal dysphonia characterized by an asthenic breathy quality are used to illustrate the program. Details of the program, termination criteria, and problems and precautions learned from treating 29 patients over a 3-year period are presented.     

Objective measures of voice production in patients complaining of laryngeal fatigue

The purpose of this retrospective study is to describe results of acoustic, aerodynamic, and videostroboscopic measures in patients complaining of laryngeal fatigue. Data were collected from 88 patients whose primary complaint was chronic laryngeal fatigue in the absence of visible laryngeal pathologies. The results revealed an abnormally high airflow rate and decreased maximum phonation time. An anterior glottal chink, anterior and posterior glottal chinks, or spindle-shaped glottal closure were found in 61% of the subjects.     

THE NUMERICAL STUDY OF AIRFLOW ALTERATION CAUSED BY NASAL TEXTURAL ANOMALY AND DIORTHOSIS 1)

鼻腔结构的改变将伴随鼻腔空气动力学特性改变,进而促使下鼻甲等发生自适应性变化。选取鼻中隔偏曲患者并行鼻中隔偏曲矫正术,部分行下鼻甲骨折外移术,将术前和术后患者行鼻腔CT 扫描,根据CT数据对鼻腔气道进行表面三维重建,运用计算流体动力学方法分析术前和术后鼻腔气道的空气动力学特征。通过研究发现,鼻腔结构矫正手术不是以双侧鼻腔气道容积对称为目的,而是应将整个鼻腔结构看作一个整体,尽可能地保护鼻腔的\绿化带",最终达到重塑鼻腔结构之目的,使鼻腔的生理功能恢复正常。     

螺旋槽端面微间隙高速气流润滑密封特性

考虑入口气流压力损失和出口阻塞效应,建立了微间隙端面高速气体润滑密封分析数学模型,对螺旋槽端面微间隙高速气流润滑密封特性进行研究.重点分析了不同密封间隙、密封压力和转速等工况条件下,入口压力损失和出口阻塞效应对开启力、泄漏率及气膜刚度等密封特性参数的影响规律.结果表明:高速气体阻塞效应使出口压力高于环境压力,压力损失使入口气膜压力下降,导致泄漏率和气膜刚度明显下降,并使开启力增加.随着密封压力和密封间隙的增加,阻塞效应增强,导致泄漏率和气膜刚度显著降低.密封压力10 MPa时,泄漏率降低可达20%,气膜刚度的下降可达30%以上.