• 제목/요약/키워드: Reflected pressure

검색결과 249건 처리시간 0.023초

The Characteristics of Risk Factors in Korean CAD Patients Comparing to American Counterpart and Its Implications to Prevention of CAD

  • Kim, Wan-Soo
    • 대한물리의학회지
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    • 제12권2호
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    • pp.9-20
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    • 2017
  • PURPOSE: The purpose of this study is to understand the difference in the risk factors of coronary artery disease (CAD) between Korean and American CAD patients to determine the discriminant factor for each group, as well as to provide useful information to be reflected in the national concern of health. METHODS: Data were collected from 248 Korean and 107 American CAD patients who underwent either percutaneous coronary intervention or coronary artery bypass grafting. By using t-test and $X^2$-test, risk factors were compared between the Koreans and Americans. To elucidate which risk factor was the most discriminant for each group, logistic regression analysis was performed. RESULTS: All risk factors, except diastolic blood pressure, showed a significant difference between the two groups. $X^2$-test showed statistical significance with respect to the smoking rate between the female groups. Moreover, there was a statistically significant difference between the two groups regarding blood total cholesterol (TC) and triglyceride, and between the male groups, here was a statistically significant difference with respect to blood high-density lipoprotein cholesterol (HDL). Diabetes mellitus (DM) was the most discriminant factor for Korean patients while TC/HDL is the most discriminant for the Americans. CONCLUSION: The characteristics of CAD risk factors were determined to be different between Koreans and Americans in this study. TC/HDL was a discriminant factor for Americans while DM was a discriminant factor for Koreans. This result implies that DM should primarily be given attention to prevent CAD in Korean adults.

수중반사파 환경에서의 근접음장 홀로그래피 적용에 대한 오차 고찰 (Error Investigation in use of Near-field Acoustic Holography in the Underwater Environment of Reflected Wave)

  • 이종주;강명환;한승진;정현주;배수룡;정우진
    • 한국소음진동공학회논문집
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    • 제24권12호
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    • pp.969-976
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    • 2014
  • Nowadays, it is required for naval ships to estimate 3D underwater radiated noise pattern in all direction at peak frequencies of hull vibration for the reduction of being detected and doing the effective operation. For this purpose, the numerical method has to be developed to calculate 3D underwater radiated noise pattern with experimental data. It is very difficult to obtain the experimental data for the real ship. Alternative to get the experimental results is to use NAH(near-field acoustic holography) in acoustic tank with experimental model. Application of NAH in acoustic tank for the experimental model needs some investigation of reflection wave from the wall of the acoustic tank and unmeasured zone of the experimental model due to the supporting structure for it. In this study, the effect of reflection wave in the acoustic tank and unmeasured area of the experimental model when using the NAH was investigated with experiment and numerical model. From these, it is known for the error due to reflection wave can be reduced when the distance between the measurement plane and source is being shorten. Also, unmeasured area of the experimental model gives rise to some error in the estimation of the far-field acoustic pressure.

수위-유속 분산 그래프를 통한 하수흐름 특성 분석 (Sanitary sewer flow characteristics through a depth-velocity scatter graph analysis)

  • 손주영;오재일
    • 상하수도학회지
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    • 제28권6호
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    • pp.647-655
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    • 2014
  • To perform long-term sewer monitoring, It is important to understand the nature of the wastewater flow that occurs at the point on early stage of the monitor and to prevent in advance a problem which may caused. We can infer the flow properties and external factors by analyzing the scatter graph obtained from the measured data flow rate monitoring data since an field external factor affecting the sewage flow is reflected in the flow rate monitoring data. In this study, Selecting the three points having various external factors, and we Inferred the sewer flow characteristics from depth-velocity scatter graph and determined the analysis equation for the dry-weather flow rate data. At the'point 1' expected non-pressure flow, we were able to see the drawdown effect caused by the free fall in the manhole section. At the'point 2', existed weir and sediments, there was backwater effect caused by them, and each of size calculated from the scatter graph analysis were 400 mm and 130 mm. At the'Point 3', there is specific flow pattern that is coming from flood wave propagation generated by the pump station at upstream. In common, adequate equations to explain the dry weather flow data are flume equation and modified manning equation(SS method), and the equations had compatibility for explaining the data because all of $R^2$ values are over 0.95.

The Relationship Between Obesity, Overweight, and the Human Development Index in World Health Organization Eastern Mediterranean Region Countries

  • Ataey, Amin;Jafarvand, Elnaz;Adham, Davoud;Moradi-Asl, Eslam
    • Journal of Preventive Medicine and Public Health
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    • 제53권2호
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    • pp.98-105
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    • 2020
  • Objectives: Obesity is regarded as one of the most prominent health threats worldwide and a serious risk factor for non-communicable diseases, such as diabetes mellitus type 2, high blood pressure, cardiovascular diseases, and some types of cancer. Given the role that societal development-as reflected by the Human Development Index (HDI)-may play in the prevalence of obesity and overweight, this study aimed to investigate the degree to which the prevalence of obesity and overweight is affected by HDI and its components. Methods: In this ecological study, the required data on HDI and its components were gathered from the latest report of the United Nations Development Program, and data on obesity and overweight were acquired from the latest reports published on the World Health Organization website. Statistical analyses were conducted using SPSS version 24.0. Results: The prevalence of obesity was determined to be significantly higher among females than males, and the gross national index per capita was found to be significantly higher for males than females (p<0.05). Significant positive correlations were found between HDI and its components and sex, as well as indices of obesity and overweight. Conclusions: A significant positive correlation exists between HDI and obesity. As policy-makers attempt to improve the general welfare of the people, they should be aware of potential unwanted effects of development on the risk of obesity and overweight among the population.

정밀질량분석기를 활용한 우레탄폼의 장기열전도도 예측을 위한 분석기법 (Long-Term Thermal Conductivity Prediction of Polyurethane Foam Applying Precision Mass Spectrometer for Cell Gas Analysis)

  • 김진석;전종한;이진복;이효진
    • 설비공학논문집
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    • 제22권10호
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    • pp.679-686
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    • 2010
  • A proprietary device is adopted to break out the membrane of cell in the rigid polyurethane foam. As it is known, the membrane of cell is hardly tearing-off thoroughly in a mechanical way due to both its elastic characteristic and micro sized pores. In this study, a novel experimental approach is introduced to burst out all gases inside the cells of the rigid polyurethane foam by abrasively grinding micro-cells completely into fine powder. The biggest advantage of this approach is to be capable of releasing all gases out from the cell even in the micro pores. As clearly reflected from the repeatability, the accuracy of the result is highly improved and high confidence in the data sets as well. For the measurements of not only gas composition but partial pressure for each gas simultaneously as well, a precision gas mass spectrometer is used in-line directly to the abrasive grinding device. To control the starting point of the polyurethane foam, all samples were prepared on site in the laboratory. Manufactured time is one of the most critical factors in characterization of cell gas composition because it is known that one of gas composition, especially, carbon dioxide, is diffused out dramatically in a short period of time as soon as it is foamed.

팽창률이 일정한 초음속 노즐흐름에 있어서 비평형 응축이 경사충격파에 미치는 영향 (Effects of Nonequilibrium Condensation on an Oblique Shock Wave in a Supersonic Nozzle of Constant Expansion Rate)

  • 강창수;권순범;김병지;홍종우
    • 대한기계학회논문집
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    • 제14권5호
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    • pp.1311-1319
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    • 1990
  • 본 연구에서는 작동유체로서 습증기와 거동이 유사한 습증기를 대기흡입식 간 헐 초음속 풍동을 이용하여, 팽창율이 일정한 노즐을 통하여 팽창시키는 경우에 대하 여 비평형 응축영역내 입치하는 경우에 대하여, 정체점 상태량의 변화에 기인되는 응 축 및 응축형격파가 경사형격파의 형상과 변화에 미치는 영향을 다음의 관점으로부터 연구하였다.

3D 디지털 현미경으로 측정한 당백가시 인쇄본의 형상 특징 (An Image Characteristics of Metal Movable Type Printing on One Hundred Poets of the Tang Dynasty by the Measurement of 3D Digital Microscope)

  • 김혜경;오카다 요시히로
    • 보존과학회지
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    • 제33권1호
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    • pp.43-49
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    • 2017
  • 류코쿠 대학 소장 "당백가시"를 중심으로 3D 디지털 현미경으로 인쇄된 종이 표면에 남아있는 금속활자의 미세표면을 관찰하여 굴곡구조와 표면 거칠기를 정량화하는 측정 방법을 소개하고자 한다. 인쇄된 종이 표면을 기준으로 활자 표면의 굴곡 현상을 선으로 측정하고 활자의 미세표면은 면으로 측정하여 수치화하여 인쇄된 종이 표면의 특성을 제시하였다. 3D 디지털 현미경 측정 방법은 비접촉, 비파괴 방법으로 많은 자료 분석과 반사광에 의한 직접 관찰이 가능하다. 그리고 클리닝이나 배접 그리고 주름을 펴기 위하여 강한 힘으로 압력을 주는 과정에서 고문서에 함유된 정보가 손실될 수 있으므로 사전 조사 방법으로 종이 표면에 남아있는 인쇄 정보를 수집하는데 유용한 방법이라고 할 수 있다.

기온과 강수특성을 고려한 남한의 기후지역구분 (Classification of Climate Zones in South Korea Considering both Air Temperature and Rainfall)

  • 박창용;최영은;문자연;윤원태
    • 대한지리학회지
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    • 제44권1호
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    • pp.1-16
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    • 2009
  • 본 연구에서는 기온과 강수특성을 함께 고려하여 남한의 기후지역을 구분하였다. 먼저 계절별 기온 및 강수량 분포를 살펴보았는데, 기온은 모든 계절에서 지형 및 위도에 의해 영향을 받았다. 강수량은 여름철에 집중되고 지역적으로는 강원 영동, 남해안, 제주에서 많았고 경북 중부지역에서 적은 분포를 보였다. 기온 및 강수량의 경험적 직교함수(Empirical Orthogonal Function)분석을 통해서 산출된 주성분점수를 입력변수로 하여 평균연결법과 Ward법을 이용한 군집분석을 수행하였다. Ward법은 지형, 위도, 해양의 효과와 기압계 이동 방향에 따른 특성을 잘 반영하였으며 행정구역에도 잘 맞게 구분되어 가장 좋은 군집결과를 보여주었다.

간호학과 신입생의 문제중심학습(PBL)의 경험에 관한 주관성연구 (Subjectivity on Problem Based Learning(PBL) Experience of Freshmen in Nursing students)

  • 박주영;양남영
    • 디지털융복합연구
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    • 제11권1호
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    • pp.329-338
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    • 2013
  • 연구의 목적은 간호학과 신입생의 문제중심학습(PBL)의 경험에 대한 주관성을 유형화하고 유형별 특성과 차이점을 분석하기 위한 것이다. 연구 대상은 간호학과 신입생 25명으로 구성하였다. 연구방법은 Q 방법론을 적용하였고, 수집된 자료는 pc-QUANAL 프로그램에 의한 주인자분석법으로 처리하였다. 심층면담과 문헌고찰을 통하여 선정된 31개의 진술문을 9점 척도의 Q 분포도상에 연구대상자에게 강제 분포하도록 하였다. 연구결과는 간호학과 신입생의 문제중심학습(PBL)에 대한 경험은 4개의 유형으로 분류되었으며 이들 유형에 의해 설명된 전체 변량은 71.6%이었다. 제 1유형은 '긍정적 부담형', 제 2유형은 '관계적 친화형', 제 3유형은 '창의적 유익형', 제 4유형은 '참여적 발전형'으로 명명하였다. 결론으로는 문제중심학습(PBL)은 간호학과 신입생에게 유용한 경험이었고 그 경험은 다양한 관점으로 인식되었다. 따라서 이상의 연구결과를 실무 중심의 간호교육을 위한 일 전략으로서 효율적인 문제중심학습(PBL) 활동에 대한 운영방안을 모색하는 데 그 기초자료로 반영해야 할 것이다.

환경문제로 인한 미소국가 이주의 지리학: 투발루의 사례 (Geography of Microstate Migration Caused by Environmental Problems: The Case of Tuvalu)

  • 숀션
    • 대한지리학회지
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    • 제51권2호
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    • pp.185-200
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    • 2016
  • 지리학은 대체적으로 인간과 환경 간의 상호연관에 대해 관심을 가지고 있다. 특히, 인간과 환경 간의 연관성은 작은 도서국가의 환경이 변화하는 모습에서 나타난다. 태평양의 저지대 산호도인 투발루는 기후변화의 원인에 주된 책임을 갖고 있지 않지만 투발루의 인구압은 지속적으로 기후변화로 인한 자원의 이용불가능과 환경적 불안정성에 영향을 받고 있다. 환경지리학과 인구지리학의 맥락 속에서 투발루의 환경적 위기와 이주민에 대한 주변 태평양 도서국과의 관계를 살펴보려 한다. 투발루인의 이주는 인구과잉과 직면된 수용 능력면에서 어떠한 어려움을 겪고 있으며 국내, 국외 이주민의 정착상황에 대해 알아볼 것이다. 이 연구는 환경 변화의 관계에서 투발루인의 이주패턴, 담론 및 전망을 분석하면서 인구지리학적인 맥락에서 현대이주문헌을 조사하려 한다.

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