• Journal of the Korean Society of Physical Medicine
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• v.8 no.2
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• pp.263-269
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• 2013

PURPOSE: The purpose of this study was to examine the effects of breathing retraining on asymmetry of diaphragm thickness in stroke patients. METHODS: This study was nonequivalent control group pre-post test design. Subjects were assigned to two different groups(intervention group=10, control group=12). Intervention group conducted breathing retraining program for six-week. Diaphragm thickness was assessed by ultrasound in B-mode with a 7.5 MHz linea probe. The collected data analyzed by Wilcoxon signed rank test and Mann-Whitney U test. RESULTS: The intervention group significantly increased diaphragm thickness ratio on paretic side but the control group showed no significant difference in diaphragm thickness ratio. The control group significantly increased asymmetry of diaphragm thickness, but intervention group showed no significant difference in asymmetry of diaphragm thickness. CONCLUSION: This study showed that breathing retraining increased diaphragm thickness ratio in stroke patients and prevent the increase of asymmetry in diaphragm thickness with stroke patients.

• Annals of Clinical Neurophysiology
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• v.19 no.2
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• pp.131-135
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• 2017

Background: Neuromuscular ultrasound can be used to assess the diaphragm. Before it can be used clinically, the reference ranges of diaphragm thickness and contractility must be determined. Methods: We measured the thickness of the diaphragm and the diaphragmatic thickening fraction (DTF) in 80 healthy volunteers with ultrasound and collected their demographic information to determine if age, sex, and body mass index (BMI) influence these measures. Results: The thickness of the diaphragm at resting end expiration was $0.193{\pm}0.044cm$ on the right side and $0.187{\pm}0.039cm$ on the left. The DTF was $104.8{\pm}50.6%$ on the right side and $114.9{\pm}49.2%$ on the left. Sex, weight, height, and BMI significantly affected the thickness of the diaphragm, but had little effect on the DTF. Conclusions: Normal reference values for the diaphragm should be helpful when evaluating the diaphragm. The DTF appears more useful than resting diaphragm thickness because it is affected less by individual variation.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.4
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• pp.1-5
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• 2015

In this work, a study was conducted to investigate the effect of diaphragm thickness on the regression rate of the hybrid rocket motor. To observe the flow pattern and the recirculation zone, visualizations of combustion chambers with different diaphragm thickness (5mm, 10mm) were performed. It was found that the case with 5 mm thickness had a larger recirculation zone and therefore, had a higher regression rate than the case with 10mm thickness due to the increased residence time and heat transfer toward the fuel surface. Finally, it was concluded that the thickness of diaphragm can be a critical parameter for the enhancement of the regression rate.

• Journal of the Korean Society of Physical Medicine
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• v.6 no.4
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• pp.437-445
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• 2011

Purpose : The purpose of this study was to analysis on diaphragm thickness and lung function of stroke patients by walking ability. Methods : We recruited thirty-five adults after stroke(20 male, 15 female) for our study. The subjects were divided into two groups; independent walking group(11 male, 9 female) and non-independent walking group(9 male, 6 female). Assessment of diaphragm thickness was performed using ultrasound in B-mode with a 7.5 MHz linea probe. During the experiment, the subject was seated in the chair. All subjects performed maximal expiratory flow maneuvers using a spirometer in order to determine the forced expiratory volume in 1 second ($FEV_1$), forced vital capacity(FVC), peak expiratory flow(PEF) and $FEV_1$/FVC. Chest expansion was measured with a tape-measure placed circumferentially around the chest wall at the xiphoid process. The collected data analyzed by independent t-test. Results : The diaphragm thickness were significant differences between the independent walking and nonindependent walking group. Values of forced vital capacity, forced expiratory volume at one second, peak expiratory flow in pulmonary function tests were significant differences between the independent walking and non-independent walking group. However, chest expansion were not significant differences in both of the group. Conclusion : This study showed that walking ability of stroke patients have influenced on diaphragm thickness and pulmonary function.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.551-554
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• 2005

This study uses a characteristic function to explain correlations between the objective function and design variables. Analysis of means and table of orthogonal array were carried out. The change of shape of diaphragm, thickness of diaphragm and voice coil weight based on the table of orthogonal array is made. Therefore this study carried to decide shape of diaphragm, voice coil weight and thickness of diaphragm for minimizing 1st natural frequency and maximizing 2nd natural frequency of diaphragm using design of experiments and characteristic function with constraints. we showed improved design factors that minimized 1st natural frequency and maximized 2nd natural frequency of diaphragm.

• Journal of the Korean Society of Physical Medicine
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• v.18 no.3
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• pp.31-37
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• 2023

PURPOSE: This study aimed to investigate the relationship between being underweight and respiratory function indicators such as pulmonary function, respiratory muscle strength, and diaphragm thickness in normal adults without lung disease. METHODS: The participants in this experiment were thirty young adults. To compare the respiratory function between the underweight and normal weight individuals, 15 participants were selected from each of the underweight and normal weight groups based on body mass index. Respiratory function tests were conducted through pulmonary function tests and respiratory muscle strength tests. Diaphragm thickness was measure with ultrasonography, and physical characteristics were obtained from grip strength and waist circumference. An independent t-test was used to compare the averages of the parameters measured in the two groups. RESULTS: In the respiratory function tests between the two groups, statistically significant differences (p < .05) emerged in the ratio of the predicted forced vital capacity (%FVC), the ratio of the predicted forced expiratory volume in one second (%FEV1), maximal expiratory pressure (MEP), and diaphragm thickness at the functional residual capacity (FRC). There was no statistically significant difference in the forced vital capacity, forced expiratory volume in one second, maximal inspiratory pressure, diaphragm thickness at the total lung capacity, and thickening ratio (p > .05). CONCLUSION: Decreases in some variables of respiratory function, such as the %FVC, %FEV1, MEP, and diaphragm thickness at the FRC were observed in underweight subjects. However, it is difficult to determine whether it affected the overall respiratory function. Future studies are needed to clearly identify the relationship between being underweight and respiratory function.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.6
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• pp.599-606
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• 2010

In the present study, actuators with diaphragms of different thickness and chambers of different diameter are fabricated to examine experimentally how the behavior characteristics of the actuator diaphragm in a thermopneumatic micropump are affected by diaphragm thickness and chamber diameter under various operating conditions with different values of input voltage and frequency. The actuator comprises a microheater set on Pyrex glass, a chamber, and a diaphragm. For all values of the input energy, as the frequency decreases below 10 Hz, the maximum center deflection of the diaphragm greatly increases irrespective of diaphragm thickness and chamber diameter. At low frequencies, as the heat energy supplied to the chamber increases, the center of deflection of the diaphragm increases; the magnitude of deflection is high for thin diaphragms and for diaphragms whose chambers have small diameters. At frequencies higher than 10 Hz, all the design variables such as diaphragm thickness, chamber diameter, and the input energy have negligible effect on the center deflection of the diaphragm.

• Korean Journal of Materials Research
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• v.21 no.7
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• pp.403-409
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• 2011

Micro speakers are used to reproduce sound in small electric and information and communications devices, such as cellular phones, PMPs, and MP3 players. The acoustical properties and sound quality, which are changed due to the decreased size of the speaker, are often adjusted varying the type and thickness of the diaphragm. The most widely used diaphragm material is thin polymer. It was previously reported by the author of this paper that the resonance frequency of a micro speaker is changed by the type and thickness of a polymer diaphragm. In this paper, the frequency response near the resonance frequency of a micro speaker was studied as functions of the type and thickness of the polymer diaphragm. While $R_{max}$ and $R_{DC}$ were affected by the type and thickness, an analysis of the electrical impedance curve revealed that $R_o(= R_{max}/R_{DC})$ and ${\Delta}f$ were not changed. Thus, $Q_{TS}$ which was function of $R_o$, ${\Delta}f$, and the resonance frequency, is only related to the resonance frequency. The increase of the resonance frequency led to a proportional rise of $Q_{TS}$. The change of the frequency response near the resonance frequency was not dependent on the type or thickness of the polymer diaphragm, but was affected by the resonance frequency.

• Steel and Composite Structures
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• v.7 no.4
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• pp.303-320
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• 2007

The objective of this study is to clarify the structural features of members consisting of connection, as a series of the previous study on the CFT column-to-beam tensile connection with combined cross diaphragm. This connection has the merits that the stress is distributed evenly on the beam flange and the diaphragm and the stress concentration is reduced, by improving the stress transfer route and restraining abrupt deformation of diaphragm. The finite element analysis was performed to find out the stress transfer through sleeve which is an important member of the connection with combined cross diaphragm. The length and thickness of sleeve were used as variables for the analysis. As the analysis results, the length and thickness of sleeve didn't influence on the capacity of the connection and played a role of a medium to transfer the stress from the diaphragm to the filled concrete. It is proposed that the appropriate length of sleeve be the same value as the diameter of sleeve and the appropriate ratio of sleeve diameter to sleeve thickness be 20. Two equations for evaluation of the load-carrying capacity of the connection were also proposed through the modification of the evaluation equation suggested in the previous study.

• JSTS:Journal of Semiconductor Technology and Science
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• v.5 no.1
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• pp.52-57
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• 2005

This paper describes a fabrication method of a circular diaphragm using boron etching stop method. It will be applied to acoustic transducers such as microphones or microspeakers and so on. The sensitivity is expected to be increased with the circular diaphragm through the simulation results to compare with a general rectangular diaphragm. The borondoped layer which is doped with solid source is sufficient for achieving an etching stop in 20 wt% TMAH, and the thickness is about $7.4{\mu}m$. The diameter of the circular silicon nitride diaphragm was measured to be 2 mm with $1{\mu}m$ thickness. The fabrication of piezoelectric acoustic devices was completed.