http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
殘留應力을 考慮한 鎔接材의 疲勞龜裂 進展擧動에 關한 硏究
최병기,이을호,국중민,기준호,임선빈,정장만 朝鮮大學校 機械技術硏究所 2000 機械技術硏究 Vol.3 No.1
The effect of welding residual stress on the initiation and propagation of fatigue crack is investigated so as to study the fatigue behavior in welding residual stress field. Especially, the relation between welding residual stress and fatigue crack opening behavior is investigated and the redistribution of residual stress as a fatigue crack propagates is examined. Following results are obtained. 1) In case of the load range is constant, as the stress ratio is changing to 0.1, 0.33, 0.5 the propagation life is constant but the growth life decreases. And than, when maximum load or minimum load is constant, as the stress ratio increases the growth life and propagation life increase. 2) The fatigue crack propagations rate da/dN appears to accelerate when the stress intensity factor range ΔK is less than 15MPa-m^1/2. 3) The residual stress that is appeared by welding decreases after cutting. 4) Fatigue crack propagation ratio is affected by tensional and compressible residual stress at the initial time, but it's similar to the original in the more than 20mm of crack length.
적외선 영상 획득을 위한 직육면체형 지상 표적에 대한 열해석 연구
이상엽,최준혁,박원희,김태국 중앙대학교 기술과학연구소 2003 기술과학연구소 논문집 Vol.33 No.-
육면체형 지상 표적의 적외선 영상을 획득하기 위하여 표적을 등성질의 사각형 격자로 세분하여 열해석을 수행하였다. 열해석을 위하여 전도, 대류 및 복사를 고려하였으며, 태양복사에 의한 입사량은 LOWTRAN 7을 이용하여 산출하였다. 다양한 조건에서 열해석을 수행하여서 물리적 온도를 산출하였으며, 이는 열상장비에서의 적외선 화상을 시뮬레이션을 하는데 기본 도구로 사용될 수 있다. The thermal modeling of a 3D ground target by considering the solar radiation through various atmospheric conditions and the eonvection by the atmospheric air is studied. Since the heat is dissipated by the conduction within the target, the target is subdivided into small rectangular elements to determine the local temperature distribution on the target which is the most important information in generating the infrared images from the target. For the thermal modeling, simple experimental models are applied for the conduction within the target and the convection by the atmospheric air and a realistic model called as the LOWTRAN 7 in used to determine the solar incidence on the target after passing through the atmospheric layer. The physical temperature distribution on the target is determined for various atmospheric conditions from the thermal modeling, and these data can be utilized for various purposes such as the infrared image generation of the target considered.
Zn-Al 아크 금속용사 피막을 적용한 구리분말 혼입 시멘트 모르타르의 전자파 차폐 성능 평가
최현준 ( Choi Hyun-jun ),최현국 ( Choi Hyun-kuk ),김형철 ( Kim Hyeong-cheol ),이한승 ( Lee Han-seung ) 한국건축시공학회 2017 한국건축시공학회 학술발표대회 논문집 Vol.17 No.1
In this study, the shielding effectiveness of the Zn-Al arc thermal metal film coated cement-mortar mixed with copper powder by reflection, absorption, multi-reflection loss in 2.25~2.65 GHz was reviewed. By enhancing the mixing ratio of copper powder, the shielding effectiveness by absorption and multi-reflection loss was increased, but shielding rate(%) based on 80 dB showed below 20%. The Zn-Al arc thermal metal film coated on specimen, the shielding rate increased 3.5 times by reflection loss.
기준구의 온도 해석을 통한 지상 물체의 표면 온도 예측 기법 연구
최준혁(Jun-Hyuk Choi),길태준(Tae-Jun Gil),김태국(Tae-Kuk Kim) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6
This paper is aimed at the development of a software that predicts the surface temperature profiles over 3-D objects on the ground by considering the spectral solar radiation through the atmosphere. This software considers the thermal energy balance within control volumes on the reference sphere by considering the direct and diffuse solar irradiance obtained by using the LOWTRAN7. The conduction within the reference sphere is assumed as one-dimensional and the results obtained from the reference sphere can then be used to obtain temperature profiles of the object with more complicated shapes by simply comparing the directions of the surface elements on the reference sphere and the actual object. In this paper, the transient temperature distribution over a cylinder is calculated by using the semi-implicit method. Results obtained by using different numbers of control volumes on the reference sphere are tested to examine the dependency of the C.V. numbers on the final accuracy.
Atomic-scale observation of plaquette antiferromagnetic order coexisting with iron superconductivity
Seokhwan CHOI,Won-Jun JANG,Jong Mok OK,Hyun Woo CHOI,Hyun-Jung LEE,Se-Jong KAHNG,Young KUK,Ja-Yong KOO,Sungbin LEE,Sang-Wook CHEONG,Jun Sung KIM,Jhinhwan LEE 한국진공학회 2016 한국진공학회 학술발표회초록집 Vol.2016 No.8
지상물체의 표면온도 계산을 위한 파장별 태양복사 흡수특성 모델링 연구
최준혁(Jun-Hyuk Choi),길태준(Tae-Jun Gil),김태국(Tae-Kuk Kim) 한국항공우주학회 2007 韓國航空宇宙學會誌 Vol.35 No.1
본 논문은 대기층을 통한 파장별 태양복사를 고려한 3차원 지상 물체의 표면 온도 분포를 예측하는 소프트웨어를 개발하는데 도움을 줄 것이다. 다양한 가스로 구성된 대기층을 통과하는 파장별 태양복사 에너지를 계산하기 위해서 LOWTRAN7을 이용하였으며, 여기서 얻어진 결과는 파장별 흡수 또는 총괄흡수 방식으로 에너지보존방정식에 반영하였다. 원통형 물체 위의 시간별 표면온도 분포를 나타내기 위해서 준 내재적 방법을 사용하여 계산하였으며 물체의 파장별 표면 복사 특성을 이용하기 위해서 태양복사를 흡수 거나 물체의 표면 방사가 이루어지는 모델을 사용하였다. 본 논문에서는 개발된 S/W의 성능 향상을 위하여 파장별 태양복사 분석 방법과 총괄태양복사 분석 방법을 각각 적용하여 본 결과 이들 두 방법 사이에는 약 3% 이내의 차이를 나타내었으나 두 방법 모두 실용적 관점에서 충분한 결과를 나타내었음을 알 수 있었다. This paper is aimed at the development of a software that predicts the surface temperature profiles of three-dimensional objects on the ground by considering the spectral solar radiation through the atmosphere. The spectral solar radiation through the atmosphere is modeled by using the well-known LOWTRAN7 code which analyzes the detailed spectral transmission characteristics by considering the atmospheric gas layers. In this paper, the transient temperature distribution over a cylinder is calculated by using the semi-implicit method. The spectral radiative surface properties such as the absorptivity and emissivity of the objects are used to model the effects of the solar irradiation and the surface emission. Both the detailed spectral modeling and the simple total modeling for the solar radiation absorption show fairly good agreement with each other by showing less than 3% difference in surface temperature.
HEMP를 대상으로 한 도전성 재료 혼입 콘크리트 전자파 차폐 벽체 시스템 개발에 관한 실험적 연구
최현준 ( Choi Hyun-jun ),최현국 ( Choi Hyun-kuk ),김재영 ( Kim Jae-young ),민태범 ( Min Tae-beom ),이한승 ( Lee Han-seung ) 한국건축시공학회 2016 한국건축시공학회 학술발표대회 논문집 Vol.16 No.2
In this study, the shielding properties of concrete with conductive materials as shielding material for electromagne- tic pulse(EMP) within 10kHz~18GHz were investigated. The shielding effectiveness of specimens were compared with different entrained materials. The shielding effectiveness were determined according to MIL-STD-188-125-1, IEEE-STD-299 at 28 days of concrete curing. The results of shielding effectiveness did not meet the criteria(80dB) severely.
최준국 ( June Kuk Choi ),최준용 ( Jun Yong Choi ),김선연 ( Sun Yeon Kim ),권선영 ( Sun Young Kwon ),신소진 ( So Jin Shin ),조치흠 ( Chi Heum Cho ),차순도 ( Soon Do Cha ),권상훈 ( Sang Hoon Kwon ) 대한산부인과학회 2012 Obstetrics & Gynecology Science Vol.55 No.11
Primary fallopian tube carcinoma is one of the rarest gynecological malignancies, accounting for 0.18% to 1.6% of all malignant neoplasms of the female reproductive tract. Preoperative diagnosis was difficult due to nonspecific symptoms and signs. This case of primary tubal cancer was diagnosed preoperatively on the basis of ultrasonography, computed tomography and magnetic resonance imaging. We have experienced a case of primary fallopian tube carcinoma before operation and so report with brief review of the literature.