원심모형실험용 소형 콘 개발 및 콘 선단저항치 특성에 관한 연구

김재현,김동준,김동수,추연욱,Kim, Jae Hyun,Kim, Dong Joon,Kim, Dong Soo,Choo, Yun Wook 대한토목학회 2013 대한토목학회논문집 Vol.33 No.2

현장지반의 공학적 특성을 파악하기 위한 콘 관입시험(Cone Penetration Test; CPT)은 원지반의 연속적인 강도 특성을 분석하여 다양한 지반변수를 손쉽게 획득할 수 있다는 점에서 널리 활용되고 있으며, 원심모형실험에서도 널리 활용되고 있다. 본 연구에서는 원심모형실험에서 콘선단저항치를 계측할 수 있는 직경이 10 mm인 소형 콘을 개발하고 원심모형실험에서의 적용성을 평가하였다. 개발된 콘으로 4자유도 로봇을 활용하여 원심모형 가속 상태에서 콘 관입시험을 수행하였다. 이 때, 원심가속도 수준을 4회 변화시켜 다양한 유효응력상태에서 콘 관입시험을 실험을 수행하였다. 그 결과, 얕은 관입깊이의 동일한 유효응력에서 콘 선단저항치는 g-level에 영향을 받으며, 선단저항치가 임계 깊이 도달하는 깊이는 g-level과 상대밀도가 커질수록 깊어짐을 확인하였다. 또한, 각 실험에서 임계 깊이에 도달한 선단저항치와 실내실험에서 획득한 지반물성을 이용하여 기존 경험식과 비교하였다. The standard CPT(Cone Penetration Test), which can be easily performed to investigate in-situ soil engineering properties, has been widely used. CPT are also widely being utilized in centrifuge model tests. In this study, a miniature cone with 10mm diameter was developed and its applicability in the centrifuge was evaluated. The developed miniature cone was equipped with a four degree-of-freedom in-flight robot. A series of cone penetration tests was performed under four centrifuge acceleration levels. As results, the cone resistances measured at the same confining stress within shallow penetration depth were affected by the centrifugal accelerations. The critical depth was proportional to the cone diameter and relative density. Cone resistances results below the critical depth and soil parameters obtained from the laboratory tests were compared with those by previously proposed empirical relations.

고등학교 공통과학 학습을 위한 멀티미디어 자료 구축

김재현,이희복,김현섭,김희수,박종욱,박현주,Kim, Jae Hyun,Lee, Hee Bok,Kim, Hyun Sub,Kim, Hee Soo,Park, Jeong Wok,Park, Hyun Ju 대한화학회 2000 대한화학회지 Vol.44 No.3

This study was designed to develop learning materials of multimediafor general science instruction of high school.this learning material was made of HTML record for each middle unit according to the general science curriculum, and was included a variety of Ietter, graph, picture, drawing, animation, and other moving image materials. And it was composed five coursewares:Content, Dictionary, Science Story,lmage Material, and Questions.The learning material is uploaded an internet website under Science Education Research Institute of Kongju National University (http://science.kongju.ac.kr), and also is provided to a CD-ROM title. 본 연구는 고등학교 공통과학 학습을 위한 멀티미디어 자료를 구축하는데그 목적을 두었다.공통과학 교육과정을 기초로 하여 문자 자료, 도표, 그림, 사진, 애니메이션, 동영상 및 음성 자료 등을 HTML 사용하여 멀티미디어 학습 자료를 개발하였다. 멀티미디어 학습 자료의 구성은 내용, 용어사전, 과학이야기, 영상자료, 그리고 질문의 다섯 분야로 나뉜다. 개발된 멀티미디어 자료는 공주대학교 과학교육연구소 홈페이지 (http://science.kongju.ac.kr)에 올려놓았으며, 또한 CR-ROM으로 제공된다.

띠 굽힘 시험을 이용한 마이크로/나노 구조물의 기계적 특성 평가

김재현,이학주,최병익,Kim, Jae-Hyeon,Lee, Hak-Ju,Choe, Byeong-Ik 재료연구소 2005 機械와 材料 Vol.17 No.4

파이핑 발생으로 인한 제방보강시 고 지형조건을 고려한 설계사례

김재현,차달성,Kim, Jae-Hyeon,Cha, Dal-Seong (사)한국토질및기초기술사회 2009 지반과 기술 Vol.6 No.2

노인의 보행에 대한 평가 도구의 신뢰도와 타당도 조사 연구

김재현,Kim, Jae-Hyun 대한물리치료학회 2009 대한물리치료학회지 Vol.21 No.1

Purpose: The examine the Reliability and Validity of the modified Emory Functional Ambulation Profile (mEFAP), Tinetti. Gait (TG), Timed Up & Go Tes t (TUG), Comfortable Gait Speed (CGS), Berg Balance Scale (BBS) in assessing gait function and balance in elderly person. Methods: The 45 community-dwelling subjects were participated in this study. Reliability was determined by intra-class correlation coefficient (ICC$_{3,1}$), Bland and Altman method (Standard Error of Measurement (SEM), Smallest Real Difference (SRD)). Results: Validity was examined by correlation the mEFAP, TG, TUG, CGS, BBS. The intra-rater reliability were High (ICC$_{3,1}$ : mEFAP=0.95, TG=0.96, TUG=0.94, CGS=0.96, BBS=0.92) and Absolute reliability were excellent (SEM: mEFAP=1.90, TG=0.21, TUG=0.28 CGS=0.25, BBS=0.52), (SRD: mEFAP=5.26, TG=0.58, TUG=0.77, CGS=0.69, BBS=1.44). There were significant correlations between assessment tool (r=.0.58$\sim$0.78, p<0.01) indicating good validity. Our results provide strong evidence that the assessment tool has good reliability, validity for assessing elderly person undergoing rehabilitation. Conclusion: The gait assessment tool is a useful scale for measuring walking function and recovery in elderly person.

기술현황분석 - 나노제품의 안전성 설계 절차

김재현,김광섭,이학주,Kim, Jae-Hyeon,Kim, Gwang-Seop,Lee, Hak-Ju 재료연구소 2013 機械와 材料 Vol.25 No.3

나노제품의 안전성은, 나노제품에 사용된 나노물질의 독성과 나노물질의 노출가능성을 동시에 고려함으로써 평가할 수 있다. 본 문서는 나노물질의 독성 데이터는 이미 확보된 것으로 가정하고, 나노제품의 안전성을 향상시키는 설계 절차에 대하여 기술한다. 나노제품에서 나노물질이 노출되는 정도를 기계적인 손상의 관점에서 평가함으로써 노출 가능성을 추정하고, 이 추정치를 나노물질의 독성값 및 노출 한계와 비교함으로써 나노제품의 안전성을 평가하거나 예측한다. 나노제품의 설계 단계에서 이러한 안전성 평가 및 예측 방안을 적용하는 방법을 설명한다.

전이성 대장암에서 표적치료와 면역치료

김재현,박선자,Jae Hyun Kim,Seun Ja Park 대한소화기암연구학회 2018 Journal of digestive cancer reports Vol.6 No.2

Colorectal cancer (CRC) is the third most common cause of cancer-related death in the world. Although the long-term outcome of patients with metastatic CRC is still poor, target therapy including anti EGFR agents and anti VEGF agents and immunotherapy including anti PD-1 antibody and anti CTLA-4 antibody have shown clinical benefits in the treatment of patient with metastatic CRC. In the future, the personalized treatment strategy based on the clinical characteristics and biologic features of patients with metastatic CRC will be necessary. In this review, we summarized the mechanisms and clinical evidences of target therapy and immunotherapy, and the guideline of clinical practice in patients with metastatic CRC.

염증성 치은에서 Proliferating Cell Nuclear Antigen(PCNA),${\alpha}$-1-antichymotrypsin, Fibronectin, Transqlutarninase의 분포에 관한 면역조직화학적 연구

김재현,유형근,김성호,Kim, Jae-Hyeon,Yoo, Hyung-Keun,Kim, Seong-Ho 대한치주과학회 1995 Journal of Periodontal & Implant Science Vol.25 No.2

Recently, available interests concerning the biologic significance of the extracellular matrix and proliferating cells associated with periodontal disease has been increased. The distribution or expression of cellular proliferation by PCNA, macrophage detection by ${\alpha}$-l-antichymotrypsin, fibronectin playing a important role in host defence mechanisms indirectly, and transglutaminase that cross linked to fibronectin and stimulate fibrin stabilization were studied in inflammed and healthy gingiva. The excised tissue samples were fixed neutral formalin for 24 hours, embedded with paraffin, sectioned at 4-61lffi in thickness, and immunohistochemically processed by LSAB method. The positive reaction to PCNA was localized in the suprabasal and basal layer of inflammed gingiva and an increasing reactivity was observed than healthy gingiva. ${\alpha}$-I-antichymotrypsin positive cells were localized in the basal layer of inflammed gingiva, and there was no or rare positive cells in healthy gingiva. The positive reaction to fibronectin in inflammed gingiva was more than healthy gingiva,"and shown in the connective tissue subjacent to basement membrane of epithelium and in the periphery of the collagen fiber bundles. The positive cells by transglutaminase in inflammed gingiva were noted in suprabasal, spinous, and keratin layer of epithelium, and slightly increased in the capillaries of connective tissues. But the results of this study demonstrated in vitro reaction. Therefore, the role of PCNA,${\alpha}$-l-antichyrnotrypsin, transglutaminase, fibronectin and coefficient with other growth factor and extracellular matrix were further investigated in vivo.

열원기기 및 펌프시스템 제어 및 운영방안

김재현,Kim, Jae-Hyeon 한국설비기술협회 1997 설비 : 공조ㆍ냉동ㆍ위생 Vol.14 No.3

자동차 시트 쿨링용 고성능·저소음 컴팩트 원심팬 개발

김재현,유서윤,정철웅,장동혁,안민기,Kim, Jaehyun,Ryu, Seo-Yoon,Cheong, Cheolung,Jang, Donghyeok,An, Mingi 한국음향학회 2018 韓國音響學會誌 Vol.37 No.6

본 논문에서는 쾌적한 운전 환경을 제공하기 위해 자동차 시트를 냉각시키기 위한 고성능 및 저소음 원심팬을 개발하였다. 먼저 팬 성능 테스터 및 전산유체역학(Computational Fluid Dynamics, CFD) 시뮬레이션을 이용하여 기존 팬 장치의 유동 특성을 분석하였다. 예측한 유동장 분석을 통하여 팬 허브 팁 근처의 와류 및 팬 허브 상단의 정체된 유동 현상이 관측되었다. 이러한 와류 및 정체 유동을 줄이기 위해 두 가지 설계 요소를 고안하였다. 첫째, 팬 날개와 팬 하우징 최소 간극(cut-off)를 증가시켜 난류강도를 줄이고 그 결과로 전체적인 음압 레벨을 줄이고자 하였다. 둘째, 허브 형상은 정체 유동을 줄이기 위해 형상을 변경하였다. 제안된 설계의 타당성을 수치해석을 통해 확인하였다. 수치해석결과를 바탕으로 프로토타입을 제작하고 팬 테스터에서 측정한 성능 곡선(P-Q curve)과 반무향실에서 측정한 음압 레벨의 분석을 통해서 유동과 소음 성능의 향상을 확인하였다. In this paper, a high-performance and low-noise centrifugal fan is developed for cooling automotive seats which provide a driver with pleasant driving environment. First, the flow characteristics of the existing fan unit was analyzed using a fan performance tester and CFD (Computational Fluid Dynamics) simulations. The analysis of the predicted flow field indicated vortex flow near the tip of fan hub and stagnation flow on the top of fan hub. Two design points are devised to reduce the vortex flow and the stagnation flow observed in the existing fan unit. First, the cut-off clearance which is the minimum distance between the fan blade and the fan housing is increased to reduce the vortex strength and, as a result, to reduce the overall sound pressure level. Second, the hub shape is more modified to eliminate the stagnation flow. The validity of proposed design is confirmed through the numerical analysis. Finally, a prototype is manufactured with a basis on the numerical analysis result and its improved flow and noise performances are confirmed through the P-Q curves measured by using the Fan Tester and the SPL (Sound Pressure Level) levels measured in the anechoic chamber.