• 소성∙가공
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• 제26권5호
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• pp.314-322
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• 2017

In the high-speed forming analysis, dynamic material properties considering a high strain rate are required. The split Hopkinson pressure bar (SHPB) experiment was performed for measuring dynamic material properties under high strain rate. The pulse shaping method was used to improve the accuracy of the SHPB experiment. A pulse shaper attached to the front of the incident bar was used for specimen dynamic stress equilibrium through stress wave control. Numerical analysis and SHPB test were performed to verify whether the pulse shaper affects the dynamic stress equilibrium in copper and Al6061 specimens. The results of SHPB test and numerical analysis show that the pulse shaper contributes to the dynamic stress equilibrium. Based on the improved stress equilibrium using a pulse shaper, the flow stress curves for copper and Al6061 materials were obtained at strain rates of 1344.4/sec and 1291.6/sec, respectively.

• 대한임상검사과학회지
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• 제53권3호
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• pp.241-248
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• 2021

본 연구는 고혈압이 있는 대한민국 성인에서 아스파르트산 아미노전이효소(aspartate aminotransferase, AST)/알라닌 아미노전이효소(alanine aminotransferase, ALT) 비율과 맥압(pulse pressure, PP) 사이의 관계를 평가하기 위해 수행되었다. 제6차 국민건강영양조사(KNHANES VI-3, 2015)에서 성인 1,515명의 데이터를 분석했다. 본 연구에서는 몇 가지 중요한 결과가 있다. 첫째, AST (odds ratio [OR], 1.018; 95% confidence interval [CI], 1.002~1.033), ALT (OR, 0.982; 95% CI, 0.969~0.996) 및 AST/ALT ratio (OR, 1.367; 95% CI, 1.027~1.819)는 고PP 결정하는 독립적인 요인이었다. 둘째, 관련변수(연령, 성별, 흡연, 음주, 규칙적인 운동, TC, TG, HDL-C, FBG, BMI, WC)를 조정한 후의 결과에서 AST/ALT ratio의 1 사분위에 대한 고PP의 OR을 기준으로, AST/ALT ratio의 2 사분위(OR, 1.188; 95% CI, 0.817~1.727) 및 AST/ALT ratio의 3 사분위(OR, 1.169; 95% CI, 0.800~1.710)는 유의하지 않았지만, AST/ALT ratio의 4 사분위(OR, 1.632, 95% CI, 1.113~2.393)에서 유의하게 높았다. 결론적으로, 고혈압이 있는 대한민국 성인에서 고PP은 AST/ALT ratio 및 AST와 양의 상관관계가 있었지만 ALT와 음의 상관계가 있었다.

• 대한예방한의학회지
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• 제3권1호
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• pp.173-179
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• 1999

압력을 증가시켜가며 맥파를 측정하여 맥파의 진동수와 푸리에 진폭이 가해준 압력에 따라 어떠한 양상을 보이는지 조사하였다. 맥파의 기본 진동수는 압력에 따른 변화를 거의 보이지 않았으며, 푸리에 진폭은 개인의 체질에 따라 몇 가지 유형으로 분류될 수 있음을 보였다. 이 유형들을 다시 푸리에 진폭이 최고점에 이를 때의 압력의 크기와 최고점에서의 상태를 유지할 수 있는 압력의 범위에 따라 맥상의 여러 형태와 연관지을 수 있음을 보였다.

• 대한임상검사과학회지
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• 제47권1호
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• pp.28-34
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• 2015

Pulse wave velocity (PWV) is used to non-invasively estimate the severity of arteriosclerosis by measuring arterial stiffness. Increased arterial stiffness measured by PWV stands for progressive arteriosclerosis and is caused by atherosclerotic risk factors. This study is focused on how brachial-ankle pulse wave velocity (baPWV) is related to the leading risk factors for arteriosclerosis or atherosclerosis. Subjects were 114, 69 males and 45 females who are in 60's and had baPWV test for acute stroke. The results are as follows: the group with increased arterial stiffness showed significant increase in HbA1c, total cholesterol, BSBP (brachial artery systolic blood pressure), BDBP (brachial artery diastolic blood pressure), CSBP (central artery systolic blood pressure), CDBP (central artery diastolic blood pressure), augmentation index (AIx) and diabetes mellitus. Correlation analysis between baPWV and atherosclerotic risk factor showed significant relationship in age, HbA1c, LDL cholesterol, BSBP, BDBP, CSBP, CDBP and augmentation index. baPWV was independently related to age and BSBP in multiple linear regression analysis. The group with increased arterial stiffness was independently related to BDBP in multiple logistic regression analysis. This study might be meaningful in evaluating the relationship between arterial stiffness and atherosclerotic risk factor in a new way, and be helped to make various studies for cardiovascular disease.

• 기본간호학회지
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• 제18권3호
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• pp.348-355
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• 2011

Purpose: This study was done to examine the effects of heat therapy on low back pain, blood pressure and pulse rate after percutaneous coronary intervention. Method: The participants in this study were 40 patients who were admitted after having percutaneous coronary intervention. The experimental group, 20 patients, had heat therapy and the control group, 20 patients, maintained a supine position for 12 hours after the intervention. Back pain (VAS), blood pressure and pulse rate were measured just after removal of the sheath, and at 2-hour intervals up to 6 hours. Data were analyzed using SPSS 15.0. Results: The experimental group had significantly lower VAS for low back pain (F=23.44, p=.001). However no significant differences were found between two groups for blood pressure and pulse rate. Conclusion: The findings indicate that heat therapy is effective in reducing low back pain in patients who have had percutaneous coronary intervention. Therefore, heat therapy could be used as nursing intervention percutaneous coronary intervention.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.551-554
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• 1999

In this paper, we developed a radial pulse transducer that has strain-gauge cantilever type load cell for total pulse detection on chongu arterial. The transducer consist of load cell and driving electronic circuits. Load cell consist of cantilever and two metal film strain gauge. The Pressure signal from chongu artery is delivered to load cell using artery rider that attached to cantilever Therefore the pressure signal convert to voltage signals by the developed transducer As the results of experiment, the developed transducer has very good linearity at pressure to voltage conversion. The total pulse detection transducer can detected three kinds of chongu artery pulse with conveniently.

• 한국초전도ㆍ저온공학회논문지
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• 제6권4호
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• pp.46-50
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• 2004

The Experimental results of the in-line type inertance tube pulse tube cryocooler for cooling superconductor RF filter are presented in this paper. The pulse tube refrigerator, which has no moving parts at its cold section, is attractive in obtaining higher reliability, simpler construction, and lower vibration than any other small refrigerators. The purpose of this study is to analyze the characteristics of in-line type inertance tube pulse tube refrigerator (IPTR), and to get main factor to improve the performance of the in-line type IPTR. Firstly, design parameters of the in-line IPTR are discussed by ARCOPTR program, and then to find optimal conditions of in-line type IPTR, cool down characteristics according to the variations of the charging pressure, inertance tube volume, regenerator volume and pulse tube volume are measured by the experiment. The lowest temperature of the cold end was about 50 K. Cooling capacity was the highest in the charging pressure of 32 atm. and 5W at 72K. On the other hand, COP of the in-line type IPTR was the highest in the charging pressure of 21 atm. and 0.018 at 77K.

• 대한한의진단학회지
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• 제16권3호
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• pp.33-40
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• 2012

Objectives: Existing cardiovascular simulators are used to evaluate artificial organs such as artificial hearts, prosthetic valves, and artificial blood vessels, and pulses are typically triggered using artificial hearts. However, the forms of pulse waves vary according to the location of arteries, and for precise assessment of artificial blood vessels, the development of simulators that generate diverse pressure pulse waves is necessary. This study developed a novel cardiovascular simulator that generates different forms of pulse waves. Methods: This simulator consists of a stepping motor, a slider-crank mechanism that transforms the rotation movement of a motor into the straight-line motion of a piston, a piston that generates pulsatile flows, a water tank that supplies fluids, an elastic tube made of silicon, and a device that adjusts the terminal resistance of fluids. Results & Conclusion: This study examined motor rotation and its operation under conditions similar to the physiological conditions of the heart. The simulator developed in this study produced diverse forms of waves, and the generated pressure waves well satisfied physiological conditions.

• 동의생리병리학회지
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• 제21권6호
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• pp.1601-1610
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• 2007

The purpose of this study was to determine whether a pulse analyzer was useful 1) to characterize the variables of pulse wave of diabetes mellitus group, compared with those of healthy subjects, and 2) to determine Sasang Constitution in diabetes mellitus group and healthy subjects. 1. The sum of pulse pressure (energy) and the ratio of systolic period area (As%), called pulse pressure-related variables, were higher in diabetes mellitus group than healthy group, while the height of dicrotic wave (h5) and the ratio of height of dicrotic wave to height of percussion wave (h5/h1), correlated with arterial compliance, were lower in diabetes mellitus group than healthy group. 2. Taeumin of diabetes mellitus group showed higher pressure-related variables than that of healthy group. 3. Soumin of diabetes mellitus group had shorter the time to dicrotic wave (t5) than that of healthy group. 4. Soyangin of diabetes mellitus group showed higher heart rates and lower values in pulse wave time-related variables, including time to dicrotic wave(t5), time to incisura (t4), total time minus time to incisura (t-t4), total time (t), width of percussion wave (w), and the ratio of width of percussion wave to total time (w/t), than that of healthy group. 5. Contact pressure (CP), sum of pulse pressure (energy), height of pre-incisura (h2), height of incisura (h4), width of percussion wave (w), time to incisura (t4), time to percussion wave (t1), variance of total time (Vt), variance of height of percussion wave(Vp) and the ratio of height of incisura to height of percussion wave (h4/h1) were used to develop the rules of Sasang Constitution Classification with about seventy five percents accuracy. These suggested that the pulse analyzer was useful to evaluate the risk degree of diabetes mellitus and to determine Sasang Constitution among either diabetes mellitus group or healthy group.

• Journal of Preventive Medicine and Public Health
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• 제22권3호
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• pp.303-312
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• 1989

To show the distribution and change of blood pressure according to age and to find factors affecting the level of blood pressure in primary school children, a follow-up study was conducted from 1986 to 1989 on 401 first grade children attending primary school in Kangwha County in 1986 and their parents. The blood pressure of the children was significantly increased according to age. The average annual increase was 1.8mmHg in systolic blood pressure and 2.5mmHg in diastolic blood pressure. The level of blood pressure did not show any significant difference in both sexes. Among children who were at or above the 80th percentile of blood pressure in the first grade, 35 and 30% of them have remained at the same level of systolic and diastolic blood pressure respectively in the fourth grade. But we could not find any significance in the tracking of blood pressure of children who were at or above the 90th percentile of blood pressure in the first grade. Weight and pulse rate were shown to be significant factors affecting systolic blood pressure in children of both sexes and mother's blood pressure and skinfold thickness were also affected systolic blood pressure in girls. The variables significantly affecting diastolic blood pressure were arm circumference and pulse rate for boys and height and pulse rate for girls.