• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.5
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• pp.63-68
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• 1998

The absolute pressure sensor using SDB wafer has been fabricated. the structure of the sensor consists of two wheatstone bridges and a diaphragm. One of the two wheatstone bridges is located on the edge of diaphragm, and the other is located on the center of diaphragm. The diaphragm cavity is sealted in vacuum (~10$^{5}$ Torr) to reduce the effect of temperature due to the vapor in the cavity on the sensitivity of pressure sensor. This is the minor method of temperature compensation method. In this experiment the main compensation method is to use the difference of the two bridge offset voltages. The drift of offset voltage with temperature is reduced by using this method so that temperature charcteristics is improved. In this method the temperature effect in the range of 22~100.deg. C was compensated over 80%.

• Journal of Trauma and Injury
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• v.37 no.1
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• pp.37-47
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• 2024

Purpose: This study aimed at developing a novel tube thoracostomy technique using the sternum, a fixed anatomical structure, as an indicator to reduce the possibility of incorrect chest tube positioning and complications in patients with chest trauma. Methods: This retrospective study analyzed the data of 184 patients with chest trauma who were aged ≥18 years, visited a single regional trauma center in Korea between April and June 2022, and underwent chest computed tomography (CT) with their arms down. The conventional gold standard, 5th intercostal space (ICS) method, was compared to the lower 1/2, 1/3, and 1/4 of the sternum method by analyzing CT images. Results: When virtual tube thoracostomy routes were drawn at the mid-axillary line at the 5th ICS level, 150 patients (81.5%) on the right side and 179 patients (97.3%) on the left did not pass the diaphragm. However, at the lower 1/2 of the sternum level, 171 patients (92.9%, P<0.001) on the right and 182 patients (98.9%, P= 0.250) on the left did not pass the diaphragm. At the 5th ICS level, 129 patients (70.1%) on the right and 156 patients (84.8%) on the left were located in the safety zone and did not pass the diaphragm. Alternatively, at the lower 1/2, 1/3, and 1/4 of the sternum level, 139 (75.5%, P=0.185), 49 (26.6%, P<0.001), and 10 (5.4%, P<0.001), respectively, on the right, and 146 (79.3%, P=0.041), 69 (37.5%, P<0.001), and 16 (8.7%, P<0.001) on the left were located in the safety zone and did not pass the diaphragm. Compared to the conventional 5th ICS method, the sternum 1/2 method had a safety zone prediction sensitivity of 90.0% to 90.7%, and 97.3% to 100% sensitivity for not passing the diaphragm. Conclusions: Using the sternum length as a tube thoracostomy indicator might be feasible.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.1
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• pp.75-81
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• 1998

This paper is to optimize single-element piezoresistor shear stress strain gauge related to aspect ratio of rectangular diaphragm. The shear stress distribution on diaphragm has been simulated by finite-element method(FEM). As simulation results, the maximum sensitivity for strain gauge was appeared at the center of diaphragm with aspect ratio 3, and in along to long edge with the ratio 2. The diaphragm with ratio 2 is not acceptable due to the yield of mask alignment in IC process technology. The optimum condition of diaphragm with respect to good sensitivity was realized in the case of ratio 3. In this case, the area by gauge was 8% of overall size of rectangular diaphragm.

• Journal of Sensor Science and Technology
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• v.28 no.1
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• pp.58-63
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• 2019

This research aims at designing a diaphragm made of SUS316L stainless steel for ultra high pressure sensors and evaluating its performance with a PZT driven deformation tester instead of high pressure chamber testing up to 100 MPa. Finite element method analysis indicates that the optimum thickness of a flat diaphragm is 1.5 mm not only to secure safety of sensors up to 100 MPa but also to enhance displacement measuring sensitivity. For this thickness, the maximum displacement at the center of the diaphragm is $5.3{\mu}m$. The PZT actuator must offer a force of 1,669 N to create a pressure of 100 MPa at the diaphragm surface in order to obtain a displacement of $5.3{\mu}m$. The performance evaluation by the PZT driven tester demonstrates nearly the same results as the same results as the sensors tested in the ultra high pressure chamber.

• Journal of the Korean Vacuum Society
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• v.14 no.2
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• pp.59-68
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• 2005

We developed a national medium vacuum standard by static expansion method. A 133 Pa capacitance diaphragm gauge was calibrated and analysed according to the document of 'Guide to the Expression of Uncertainty in Measurement' of ISO. The results showed that the expanded uncertainty of $2.628\times10^{-3}$ Pa at $95\%$ confidence level and coverage factor of k=2.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.763-766
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• 2004

Recently, various acoustic artifacts that contains speaker have been produced such as cellular phone. Speaker consists of diaphragm generating sound and coil vibrating diaphragm. Generally, good speaker means that it has a wide frequency range, high output power rate to input power and flat sound pressure level in specified frequency range. Acoustic characteristic was estimated through the experiment and computer simulation, or sound power was controlled with acoustic sensitivity in a natural frequency range fer last decade. However, the flatness of sound pressure level has not been considered to enhance the sound quality of a speaker. Tn this study, a method for speaker design is proposed for a good acoustic characteristic, which is flatness of SPL(sound pressure level) and wideness between the first and second natural frequency. SYSNOISE is used fer acoustic analysis and ANSYS is used for harmonic response analysis and modal analysis. Optimization for acoustic characteristics of a speaker diaphragm is performed using ModelCenter. All analyses are done within a frequency domain. And we confirm that the experimental and computational simulations have similar trend.

• Journal of the Korean Vacuum Society
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• v.14 no.3
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• pp.103-109
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• 2005

A new medium vacuum primary standard using the static expansion method was developed in KRISS. In order to evaluate the performance of the equipment, we compared the medium vacuum standard with an ultrasonic interferometer manometer using two capacitance diaphragm gauges, the measuring ranges of which were 133 Pa and 1,333 Pa respectively. The result, Error normalized values, showed that the two standards are coincident each other within the range of combined uncertainty at calibrated pressure of $3pa\;\sim\;100pa$.

• Structural Engineering and Mechanics
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• v.64 no.2
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• pp.195-204
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• 2017

Analytical and experimental studies of the innovative pipe in pipe damper have been recently investigated by the authors. In this paper, by adding lead or zinc infill or slit diaphragm inside the inner pipe, it is tried to increase the equivalent viscous damping ratio improving the cyclic performance of the recently proposed multi-level control system. The damper consists of three main parts including the outer pipe, inner pipe and added complementary damping part. At first plastic deformations of the external pipe, then the internal pipe and particularly the added core and friction between them make the excellent multi-level damper act as an improved energy dissipation system. Several kinds of added lead or zinc infill and also different shapes of slit diaphragms are modeled inside the inner pipe and their effectiveness on hysteresis curves are investigated with nonlinear static analyses using finite element method by ABAQUS software. Results show that adding lead infill has no major effect on the damper stiffness while zinc infill and slit diaphragm increase damper stiffness sharply up to more than 10 times depending on the plate thickness and pipe diameter. Besides, metal infill increases the viscous damping ratio of dual damper ranging 6-9%. In addition, obtained hysteresis curves show that the multi-level control system as expected can reliably dissipate energy in different imposed energy levels.

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.2
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• pp.181-187
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• 2019

Purpose: The purpose of this study was to investigate the activity of respiratory muscle and lung capacity during deep breathing with electrical stimulation of the vagus nerve. Methods: This study was conducted on 30 healthy adults in their 20s. Subjects were randomly performed to deep breathing or deep breathing with vagus nerve electrical stimulation. All subjects' diaphragm and internal oblique muscle activity were measured during deep breathing by electromyography, and lung capacity was measured by spirometry immediately after beep breathing. In the vagus nerve stimulation method, the surface electrode was cut into the left ear and then electrically stimulated using a needle electric stimulator. Results: The activity of diaphragm was significantly increased in deep breathing with vagus nerve electrical stimulation than in deep breathing. However, lung capacity did not show any significant difference according to the condition. Conclusion: Vagus nerve electrical stimulation could induce diaphragm activity more than deep breathing alone. Deep breathing with vagus nerve electrical stimulation may enhance the activity of the respiratory muscles and is expected to be an effective treatment for the elderly or COPD patients with poor breathing ability.

• Progress in Medical Physics
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• v.28 no.1
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• pp.1-10
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• 2017

The difference between three-dimensional (3D) and four-dimensional (4D) dose could be affected by factors such as tumor size and motion. To quantitatively analyze the effects of these factors, a phantom that can independently control each factor is required. The purpose of this study is to develop a deformable lung phantom with the above attributes and evaluate the characteristics. A phantom was designed to simulate diaphragm motion with amplitude in the range 1~7 cm and period up to ${\geq}2s$ of regular breathing. To simulate different tumors sizes, custom molds were created using a 3D printer and filled with liquid silicone. The accuracy of the phantom diaphragm motion was assessed by comparing measured motion with predicted motion. Because the phantom diaphragm motion is not identical to the tumor motion, the correlation between the diaphragm and tumor motions was calculated by a curve fitting method to emulate user-intended tumor motion. Tumors of different sizes were located at same position, and tumor set-up positions were evaluated. The accuracy of phantom diaphragm motion was better than 1 mm. The diaphragm-tumor correlation showed that the tumor motion in the superior-inferior direction increased with increasing diaphragm motion. The tumor motion was larger in the $10cm^3$ tumor than in the $90cm^3$ tumor. The range of difference between the tumor set-up positions was 0 to 0.45 cm. This phantom showed independently adjusting factors such as tumor size and motion to facilitate quantitative analysis of the dosimetric impact of respiratory motion according to these factors.