• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.189-194
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• 2002

Many researches in the past have shown that a majority initial cracking in concrete are caused during early age period. Therefore, the close examination of early age concrete behavior under various stress conditions is necessary to fully understand the cracking mechanism of concrete. In this study early age cement paste specimen is axially strained up to 20% of its original length by laterally reinforcing it. This type of test is called "Tube Squash Test" and has been previously used to apply up to 50% axial strain on concrete. Microscopic analyses (XRD, FESEM, EDS and DSE/TG) are performed on 20% axially strained early age cement paste specimen. The analysis results show that the microscopic structures and material characteristics of 20% axially strained cement paste remained same as the unstrained cement paste.

• 콘크리트학회논문집
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• 제14권3호
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• pp.331-340
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• 2002

본 연구에서는 해사를 사용한 초기재령 콘크리트의 자기 및 건조 수축의 구속에 의한 균열발생을 재현하기 위해 유한요소 해석을 실시하였다. 이를 위해 미시역학적 관점에서 열역학적 평형관계를 토대로 해사를 사용한 초기재령 콘크리트의 수화발열 모델, 수분이동 모델 및 건조수축 예측 모델 등의 재료 모델을 정립하여 해석알고리즘을 제안하였고 초기재령에서 해사를 사용 한 콘크리트의 자기 및 건조수축의 구속에 의해서 발생하는 구속응력의 경시변화와 그에 따른 균열발생 및 시기에 관한 균열평가를 목적으로 염분 함유량을 변화시킨 콘크리트의 시편에 대하여 일축 방향 변형구속 실험을 실시하였다. 실험결과 초기재령 콘크리트내 염분 함유량의 증가가 강도발현에 큰 영향을 미치지 못하는 반면 건조수축량을 증가시키므로 일축 방향 변형 구속시 동일 재령에서 높은 구속인장력이 발생하고 그로 인해 균열발생시기를 앞당기는 것을 밝혔다. 또한 구속시험과 동일한 조건으로 해사를 사용한 콘크리트 시편에 대한 응력해석을 실시하여 부재내부에 도입된 건조수축 응력 및 균열 발생의 시간 의존적 변화를 재현하여 그 타당성을 실험결과와 비교를 통해 검증하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
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• pp.79-80
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• 2010

곡선형 강 박스 거더의 상부 플랜지를 구성하는 콘크리트의 건조수축 및 크리프 현상으로 인해 발생하는 재령종속적 비틀림 거동을 분석하기 위한 실험실 실험을 수행하였다. 재령종속 증분탄성계수(Age-Dependent Incremental Tangent Modulus, ADITM) 에 근거하는 유한요소해석법을 사용하여 실험체의 시간종속적 거동을 예측하였다.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제28권2호
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• pp.281-302
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• 2014

우리는 본 연구에서 황금비의 역사, Markowsky의 황금비 판단 기준, 그리고 황금비에 대한 오해를 알아보았다. 쿠푸왕의 대 피라미드에는 황금비가 존재하지 않는다는 Markowsky의 주장에 반하여 필자는 황금비의 존재를 주장하였다. 초 중등 교과서와 수학사 관련 국내 출판 책자에서는 황금비의 예로 쿠푸왕의 대 피라미드와 파르테논 신전을 사용하고 있는데 이에 대한 잘못된 서술을 알아보고 황금비 지도의 대안으로 동적 조화 입장에서 현대 산업 디자인, 항공공학, 건축 디자인, 스크린 디자인 등의 예를 제시하였다. 또한, 기축시대가 우리나라 학교수학에 미친 영향을 탈레스와 황금비 중심으로 알아보았다.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제29권2호
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• pp.157-196
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• 2015

본 논문의 목적은 중등 수학교과서에 기술되어 있는 수학사의 주요 문제점을 알아보고, 그리고 중등 수학교과서에 수학문화의 전이가 반영되어야함을 주장하는데 있다. 교과서에서 다루는 수학사는 기축시대와 고대 그리스에서 고대 이집트, 고 바빌로니아, 그리고 이슬람 수학을 제외한 유럽으로의 수학문화의 전이가 반영되어 있다. 우리는 이를 알아보고 수학사적 문제의 대안을 제시하였다.

• Clinical Pain
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• 제18권2호
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• pp.82-87
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• 2019

Objective: To evaluate which Korean pain descriptors are frequently used in the patients with neuromusculoskeletal diseases and compare the frequency of Korean pain descriptor according to age, gender, pain pattern and intensity, and clinical diagnosis. Method: Two hundreds sixty nine patients with neuromusculoskeletal diseases were enrolled in this study. The patients were asked to fill out a pain questionnaire using Korean. The Korean pain descriptors were collected and classified according to neurophysiological mechanism. The frequency of Korean pain descriptor was analyzed by age, gender, pain pattern and intensity, and clinical diagnosis. They were divided into axial spine and peripheral joint pain group depending on the location of causal disease and shoulder pain descriptors were divided into intra-articular and bursa group. Results: Among 24 Korean pain descriptors, 'arida' was the most common pain descriptor, followed by 'ssusida' and 'jjireunda'. When the pain descriptors were classified according to neurophysiological mechanism, superficial somatic pain was the most common, followed by deep somatic pain. There was a significant difference in the frequency of the pain descriptor between axial spine and peripheral joint pain group (p=0.007). The pain descriptor 'danggida' was used significantly more in the patients with axial spine pain than peripheral joint pain (p=0.024). However, there was no significant difference in other factors. Conclusion: The patients with neuromusculoskeletal diseases expressed their pain using various Korean pain descriptors with stabbing nature and superficial somatic pain. Our results may be helpful to assess and develop a new Korean pain quality measure in the patients with neuromusculoskeletal diseases.

• 대한디지털의료영상학회논문지
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• 제17권1호
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• pp.13-18
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• 2015

Purpose : Skip the repetitive HRCT axial scan in order to reduce the exposure of patients during chest HRCT scan, Helical Scan Data into a reconstructed image, and exposure of the patient change and visually evaluate the usefulness of the HRCT images. Materials and method : Patients were enrolled in the survey are 50 people who underwent chest CT scans of patients who presented to the hospital from January 2015 to March 2015. 50 people surveyed 22 people men and 28 people women people showed an average distribution of 30 to 80 years age was 48 years. 50 patients to Somatom Sensation 64 ch (Siemens) model with 120 kVp tube voltage to a reference mAs tube current to mAs (Care dose, Siemens) as a whole, including the lungs and the chest CT scan was performed. Scan upon each patient CARE dose 4D (Automatic exposure control, Siemens Medical Solution Erlangen, Germany) was to maintain the proper radiation dose scan every cross-section through a device that automatically adjusts the tube current of. CT scan is the rotation time of the Tube slice collimation, slice width 0.6 mm, pitch factor was made under the terms of 1.4. CT scan obtained after the raw data (raw data) to the upper surface of the axial images and coronal images for each slice thickness 1 mm, 5 mm intervals in the high spatial frequency calculation method (hight spatial resolution algorithm, B60 sharp) was the use of the lung window center -500 HU, windows were reconstructed into images in the interval -1000 HU to see. Result : 1. Measure the total value of DLP 50 patients who proceed to chest CT group A (Helical Scan after scan performed with HRCT) and group B (Helical Scan after the HR image reconstruction to the original data) compared with the group divided, analysis As a result of the age, but show little difference for each age group it had a decreased average dose of about 9%. 2. A Radiation read the results of the two Radiologist and a doctor upper lobe and middle lobe of the lung takes effect the visual evaluation is not a big difference between the two images both, depending on the age of the patient, especially if the blood vessels of the lower lobe (A: 3.4, B: 4.6) and bronchi(A: 3.8, B4.7) image shake caused by breathing in anxiety (blurring lead) to the original data (raw data) showed that the reconstructed image is been more useful in diagnostic terms. Conclusion : Scan was confirmed a continuous, rapid motion video to get Helical scan is much lower lobe lung reduction in visual blurring, Helical scan data to not repeat the examination by obtaining HRCT images reorganization reduced the exposure of the patient.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.427-432
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• 2003

An analytical method to predict the flexural behavior of composite girder is presented in which the early-age properties of concrete are specified including maturing of elastic modulus, creep and shrinkage. The time dependent constitutive relation accounting for the early-age concrete properties is derived in an incremental format by expanding the total form of stress-strain relation by the first order Taylor series with respect to the reference time. The sectional analysis calculates the axial and curvature strains based on the force and moment equilibriums. The deflection curve of the box girder approximated by the quadratic polynomial function is calculated by applying to the proper boundary conditions in the consecutive segments. Numerical applications are made for the 3-span double composite steel box girders which is a composite bridge girder filled with concrete at the bottom of the steel box in the negative moment region. The one dimensional finite element analysis results are compared with those of the three dimensional finite element analysis and the analytical method based on the sectional analysis. Close agreement is observed among the three methods.

• 대한치과교정학회지
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• 제12권1호
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• pp.27-30
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• 1982

The growth changes in position of upper and lower jaws, incisal inclination in relation to inferior cranial base have been described. Twenty five males was studied quantitavely by means of serial cephalometric reontgenogram from seven to thirteen years of age. The findings seem to warrant the following conclusions: 1. Growth change in anteroposterior relationship of upper and lower jaws to the anterior cranial base showed very little change before eleven years of age but axial inclination of incisal teeth tended to become labiaization in relation to the anterior cranial base. 2. kiter eleven years of age, there wasn't nearly labialization of incisal teeth but jaw prognathism occurred a little in relation to the anterior cranial base.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
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• pp.147-148
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• 2010

콘크리트 구조물의 재령종속적 거동에 대한 유도된 구성관계의 예측특성과 정도 분석을 목적으로 세 종류의 실험을 수행하였다. 이 실험은 구성관계를 정의하기 위해 요구되는 건조수축과 크리프 및 탄성계수발현에 관한 세 기본관계식을 유도하기 위한 원통형 공시체 실험과 원통형공시체 내에 축방향 철근을 매립한 철근매립형 공시체 축하중 실험 및 자중과 함께 등분포하중을 받는 RC 보 실험으로 구성하였다.