• Electrical & Electronic Materials
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• v.10 no.10
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• pp.1022-1028
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• 1997

In this paper we present the construction details and output characteristics of a diaphragm-type pressure sensor with Cu-Ni(53:47) thin-film strain gauges. In order to improve the sensitivity and the temperature compensation two circumferential gauges are placed near the center of the diaphragm and two radial gauges are located near the edge. For all the gauges the relative change in resistance ΔR/R with pressure is of the order 10$^{-3}$ for the maximum pressure. The output is found to be linear over the entire pressure range(0-30kfg/cm$^2$)and the output sensitivity obtained is 1.6mV/V. The maximum nonlinearity observed in output characteristics is 0.35%FS for 5V excitation and the hysteresis is less than 0.1%FS.

• International Journal of Automotive Technology
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• v.6 no.2
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• pp.87-93
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• 2005

Spray patterns were visualized using the shadowgraph method, and the droplet size and velocity were measured using PDPA for high-pressure injections up to 2,600 bars. The spray pattern and spray characteristics, such as penetration, spray width, spray angle, droplet size, injection duration, and droplet velocity, were investigated to determine the suitable injection pressure. Spray penetration, width, angle, and velocity increased continuously up to 2,600 bars with the injection pressure in a high-pressure region. The rate of improvement of the above spray characteristics, however, declined rapidly, when the injection pressure reached 2,000 bars. The injection duration and droplet size generally decreased with the increase in the injection pressure, while the rate of improvement decreased abruptly after 2,000 bars. Consequently, the improvement rate of the spray characteristics became blunt at over 2,000 bars. This means that the suitable injection pressure is around 2,000 bars.

• Journal of Korean Biological Nursing Science
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• v.21 no.4
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• pp.275-282
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• 2019

Purpose: This study aimed to identify the differences in blood pressure among adults in the community according to age and time of the blood pressure measurement. Methods: This was a secondary analysis study, using data from a 2015 community health survey, conducted by the Korea Centers for Disease Control and Prevention. The data of three-time-measured blood pressure were collected from 337 subjects, 25, 35, 45, 55, 65, 75 years old, which are median ages by each age group. Results: The primary systolic pressure was significantly higher than the secondary systolic pressure (t= 3.46, p= .001) and the tertiary systolic pressure (t= 4.83, p= .001). The secondary systolic pressure was higher than the tertiary measurement (t= 2.05, p= .041). There was no significant difference between the three-time-measured values for diastolic pressure. There was a significant interaction between measurement times and age in the systoic blood pressure readings (F= 1.95, p= .036). However, there was no significant interaction between measurement times and age in the diastolic blood pressure readings (F= 1.03, p= .418). Conclusion: The findings suggest that attention must be paid to the use of blood pressure values in studies or one-time-measured clinical blood pressure values. In particular, the differences in systolic pressure readings taken at different times in the older age groups were significant. Therefore, it is more important to carefully assess blood pressure in adults over the age of 45 compared to other age groups.

• Research in Community and Public Health Nursing
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• v.10 no.1
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• pp.154-172
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• 1999

In order to analyse the prevalence rate of hypertension and the actual conditions of control, we selected five districts out of eleven eups and myuns in Chinan Country. We administered structured questionaries to 309 adults above the age of 40, computerized the data using SPSS - PC+. More than 40.1% of adults over 40 in Chinan County have health disorders ranging from high blood pressure to hypertension including alert high blood pressure at 36.2%, relatively high. Among general characteristics, differences in the rate of hypertension were influenced by age, occupation and places of residence. Over 71 who are engaged in agriculture, who don't have jobs, who reside in Sungsu, Jungchun, Chinan-eup all have higher hypertension rates than other groups. Accordingly, the control of hypertension should be focused on these people. As a result of the control of blood pressure, the survey showed 93.0% of the subjects were checked mainly at hospitals clinics, health centers subhealth centers and community health posts more than once a year, relatively high level of blood pressure management. However, the difference between their blood pressure measurements at ordinary times and the level of blood pressure at the time of research was quite considerable. Only 47.3% of the subjects diagnosed with high blood pressure and 70.3% of the subjects with normal blood pressure recognized their blood pressure accurately 52.7% of the subjects diagnosed with high blood pressure showed errors in understanding their blood pressure at normal times. Because these errors can cause problems in the control of blood pressure, proper management should be executed through a systematic examination. As a result of the high blood pressure control condition, the average period of hypertension was 74.5( ${\pm}92.8$) months, 92.3% of the subjects were diagnosed with high blood pressure at hospitals clinics, health centers subhealth centers community health posts, but only 29.5% were examined after a general check up on high blood pressure was completed. 70.5% were diagnosed with high blood pressure only after measuring their blood pressure. 14.1% of the subjects were hospitalized because of falls influenced by high blood pressure. 33.3% attended hospitals and health centers regularily for medical treatment and this shows how low the rate of the control of blood pressure. Most people did not undergo medical treatment, because they had no painful symptoms (46.7%), they didn't need to take the medicine(28.9%), or they forget to take the medicine(20.0%). These problems in the control of hypertension were discovered in the process of diagnosing high blood pressure at health medical institutions. Many people did not recognize the need for consistent control of blood pressure. That is, although the diagnosis for high blood pressures performed at hospitals clinics, health centers subhealth centers and community health posts, was 92.3%, more than 70.5% of the subjects were not examined completely with regard to blood pressure. Accordingly, heath medical institutions must diagnose high blood pressure not only by only measuring blood pressure but also by using systematic process of examination. As for the people diagnosed with high blood pressure, one should perform consistent medical approaches and help them to recognize the importance of the continuous control of blood pressure through subject-oriented education. Problems the subjects experienced were the following numbness in the limbs easily paralyzed stitches in their shoulders which felt painful, stiff necks, occiputs felt heavy, headaches when they got up in the morning, felt dizzy when standing and moving their heads and poor eyesight. The rate of knowledge related to high blood pressure was 78.7 points, comparatively low. Whether they had normal blood pressure or hypertension made no difference. These results are not desirable. Adult-oriented education forgot the prevention and management of high blood pressure should be implemented. Hypertensive-oriented education should be especially reinforced. Because there was a difference in the level of knowledge according to age, academic career, occupation or place of residence, education related to hypertension should be intensified and focused on those over the age of 71 those who did not attend school, those who do not have jobs and are engaged in agriculture and residents living in Bugui, Jungchun regions. The degree of healthy life practice in hypertensives is poor, particularly weight control, as opposed to people who have normal blood pressure. It makes no difference in smoking, the amount of daily smoking, drinking, the control of salt because each result means that they are not practicing healthy life or modifying their life-style. The development and programs to improve a healthy life should be executed.

• Wind and Structures
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• v.33 no.6
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• pp.463-470
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• 2021

This study investigates the aerodynamic characteristics of NACA series airfoil by altering the trailing edge in the form of extended and serrated sections. This contemporary advent examined NACA 0020 airfoil experimentally at the angle of attack ranging from 0° to 45° and for the Reynolds number of 2.46 × 105. To figure out the flow behaviour, the standard average pressure distribution over the airfoil surface is estimated with 50 pressure taps. The time series surface pressure is recorded for 700 Hz of sampling frequency. The extended trailing edge of 0.1 c, 0.2 c and 0.3 c are attached to the base airfoil. Further, the triangular serration is introduced with the base length of 2 cm, 4 cm and 6 cm. Each base length with three different amplitudes of 0.1 c, 0.2 c and 0.3 c were designed and equipped with the baseline case at the trailing edge and tested. The aerodynamic force coefficient, as well as pressure coefficient are presented. The obtained data advises that modification in the trailing edge will reflect the aerodynamic characteristics and the flow behaviour over the section of a wing. Resultantly, the extended trailing edge as a thin elongated surface attached to a base airfoil without revising the main airfoil favors good lift increment. The serrated trailing edge acts as a flow control device by altering the flow pattern results to delay the stall phenomenon. Besides it, improves lift co-efficient with less amount of additional drag. This extended and serrated trailing edge approach can support for designing the future smart airfoil.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.812-817
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• 2001

Impinging spray characteristics were investigated to find suitable injection pressure by using high pressure injection system. Spray radius and spray height were increased continuously until 2,500bar but the rate of enhancement was decreased suddenly over this injection pressure region. It is expected that the maximum suitable injection pressure of impinging spray exists at around 2,500bar.

• Journal of ILASS-Korea
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• v.8 no.4
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• pp.17-23
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• 2003

To find suitable injection pressure, ultra high pressure impinging spray characteristics were investigated with a impinging distance and a impinging angle by using high pressure injection system. As impinging distance was increased, spray penetration was decreased but spray height was increased. For increase of injection pressure, spray penetration and spray height were increased until 2,500bar. But over this injection pressure region, the rate of increase was decreased suddenly.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.6
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• pp.7-12
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• 2005

In order to analyze the microscopic spray characteristics of free spray in ultra high pressure region, the droplets size and velocity of free spray injected under atmosphere condition were measured by PDPA. As injection pressure became ultra high pressure, the droplets size was decreased continuously due to the increase of mutual reaction between droplets and air. But the decreasing rate became moderate. The velocity was increased until 250 MPa, and then decreased over that of injection pressure. It was seemed that the droplet size was similar in range of $280\~350\;MPa$, but increased in 414 MPa, even though injection pressure was increased. The microscopic spray characteristics of free spray got worse in 414 MPa.

• 한국기계연구소 소보
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• s.20
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• pp.49-55
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• 1990

Filament-Wound composite pressure vessels offer significant weight saving over the conventional metal pressure vessels. S-2 glass/epoxy pressure vessel was designed, fabricated and tested. It was considered, in the analysis that the matrix and the metal liner of FRP pressure vessel shared the internal pressure. The thicknesses of hoop and helical layers were determinded by the computer program developed for the design of FRP/Metal structural pressure vessel. The computer program increased the structural efficiency about 14% comparing with the netting analysis. The experimental measurement on the deformation by internal pressure agrees with the theoretical analysis within the accuracy of 5%.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1190-1195
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• 2004

In this study, numerical investigation has been performed on the evolution of key-hole geometry during high-energy density laser welding process. Unsteady phase-change heat transfer and fluid flow with the surface tension and recoil pressure are simulated. To model the overheated surface temperature and recoil pressure considering subsonic/sonic vapor flow, the one-dimensional vaporization models proposed by Ganesh and Knight are coupled over liquid-vapor interface. It is shown that the present model predicts well both the vaporization physics and the fluid flow in the thin liquid layer over the other model.