고체로켓모터의 비선형 연소 불안정성 예측 기법

홍지석(Ji-Seok Hong),문희장(Hee-Jang Moon),성홍계(Hong-Gye Sung),엄원석(Won-Seok Um),서성현(Seonghyeon Seo),이도형(Do-hyung Lee) 한국추진공학회 2016 한국추진공학회지 Vol.20 No.1

고체모터의 인히비터에 의한 압력 진동 특성 LES 연구

홍지석(Ji-Seok Hong),문희장(Hee-Jang Moon),성홍계(Hong-Gye Sung) 한국추진공학회 2015 한국추진공학회지 Vol.19 No.1

대형 고체로켓의 그레인간 인히비터에 의한 유동 교란 특성 LES

홍지석(Ji-Seok Hong),허준영(Junyoung Heo),문희장(Hee-Jang Moon),성홍계(Hong-Gye Sung),이도형(Dohyung Lee),김윤곤(Yoon-Gon Kim) 한국추진공학회 2011 한국추진공학회 학술대회논문집 Vol.2011 No.11

대형 고체로켓에 존재하는 그레인간 인히비터로 인해 발생하는 유동과 압력의 교란 현상을 조사하기 위해 Large Eddy Simulation과 Proper Orthogonal Decomposition(POD) 기법을 적용하였다. 해석 결과는 실험 결과와 유사하며 정량적 및 정성적 분석을 수행하였다. 인히비터에서 발생하는 와류(vortex)는 노즐헤드와 충돌하여 발생하는 음향가진(acoustic source)에 영향을 받아 주기적으로 발생하는 것을 확인하였다. 또한 3차원 해석 결과 와류가 노즐헤드에 충돌하는 과정에서 유동이 불균형한 형상으로 분해되면서 노즐 출구 유동이 회전하여 롤 토크를 유발함을 확인 하였다. Detail flow structure in a large solid rocket motor with two inhibitors has been investigated using 3D Large Eddy Simulation and Proper Orthogonal Decomposition(POD) analysis. Vortex shedding frequencies periodically occurred by inhibitors are coupled with flow acoustics induced by the impinging of vorticity on nozzle head. As a result of 3D analysis, it was observed that the nozzle exit flow causes roll-torques from the vortex being decomposed in unbalanced shape for the impinging of vorticity on the nozzle head.

다중 인히비터가 존재하는 고체로켓모터의 내부 유동 불안정과 롤토크 특성에 대한 LES

홍지석(Ji-Seok Hong),문희장(Hee-Jang Moon),성홍계(Hong-Gye Sung),이도형(Do-hyung Lee) 한국추진공학회 2013 한국추진공학회 학술대회논문집 Vol.2013 No.5

고체로켓의 그레인간 인히비터로 인해 발생하는 유동과 압력의 교란 현상을 조사하기 위해 Dynamic Large Eddy Simulation 기법을 적용하였다. 주파수 분석 해석 결과는 실험 결과와 유사하며, 불안정성을 가진하는 원인을 찾기 위해 인히비터의 위치를 변경하여 정량적 및 정성적 분석을 수행하였다. 인히비터에서 발생하는 와류(vortex)는 노즐헤드와 충돌하여 발생하는 음향가진(acoustic source)에 영향을 받아 주기적으로 발생하는 것을 확인하였다. 연소실 내부 불안정성을 가진하는 요인은 공명주파수와 관계가 있는 것을 확인하였다. 인히비터에서 발생한 와류가 불균형한 형상으로 분해되면서 노즐 출구 유동이 회전하여 롤 토크를 유발함을 확인 하였다. Detail flow structures in a solid rocket motor with two inhibitors havev been investigated using a 3D Dynamic Large Eddy Simulation. The oscillation frequencies from two inhibitors compare reasonably well with the experimental data. And the locations of the rear inhibitor have been numerically tested to find the location agitating pressure oscillation in the chamber. Vortex shedding frequencies periodically occurred by inhibitors are coupled with flow acoustics induced by the impinging of vorticity on nozzle head. The major source of triggering pressure oscillation in the combustor is the resonance with the acoustic longitudinal half mode. It was observed that the counter rotating vortices in the nozzle flow produce roll torque.

진피내 멜라닌세포성 병변에서 Integrin 표현과 아포프토시스 세포에 관한 연구

홍문희 ( Moon Hee Hong ),정병수 ( Byound Soo Chung ) 대한피부과학회 1998 대한피부과학회지 Vol.36 No.1

Background: Many mammals normally have a population of dermal melanocytes but these are not found in man, In humans, persistent dermal melanocytes can occur in the Mongolian spot, the nevus of Ota, and the blue nevus. Mongolian spot develops in the fetal or neonatal time and disapperars almost invariably during childhood. In contrast, nevus of Ota and blue nevus are not usually present at birth and persists in adult life. Recently, it was established that apoptosis can be involved in the development of melanocytes. The integrins mediate cell-cell and cell-matrix interactions, and apoptosis can be induced by disruption of cell-matrix interactions. Objective : The purpose of this study was to investigate the expression of integrins (a2 , a3 , ar) and in situ detection of fragmented DNA in Mongolian spot, nevus of Ota, and blue nevus. Methods : Formalin-fixed and paraffin-embedded tissues from 8 cases of Monglian spot, 5 cases of nevus of Ota, and 4 cases of blue nevus were immunolabelled with monoclonal antibodies TM directed against az, ay, and av integrin, and stained with ApopTag in situ using an Apoptosis Detection kit. The cases of Mongolian spot were divided into two groups in which group A represented the the cases of more than 45 melanocytes and group B represented the cases of less than 10 melanocytes in a tissue section of 4-mm taken from punch biopsy specimens. Results: Blue nevi showed az and e integrin expressions in dermal melanocytes and weak to negative staining of g v integrin in comparison with all positive expressions of a z, a s, and g y integrin in A group-Mongolian spots and nevi of Ota. The B group-Mongo]ian spots showed the continuous expressions of a z and a y integrin with negative expressions of a v integrin. The ApopTag kit staining was all negative in the Mongolian spots, nevi of Ota, and blue nevi. Conclusion . Our results support the view that dermal melanocytic tumors, such as the Mongolian spot, the nevus of Ota, and the blue nevus, might be induced by the disturbance or inhibition of the apoptotic process of the melanocytes, and that the spontaneous disappearance of the Mongolian spot may not be related to the apoptosis. (Korean J Dermatol 1998;36(1): 52-58)

용융아연도금강판 코팅층 접합강도에 미치는 스팽글 크기의 영향

홍문희 ( Moon Hi Hong ),이주연 ( Ju Youn Lee ),백두진 ( Doo Jin Paik ) 대한금속재료학회(구 대한금속학회) 2011 대한금속·재료학회지 Vol.49 No.11

Effects of spangle size and crystallographic characteristics on the surface appearance, galling properties, and adhesive strength of hot-dip galvanized steel sheets have been investigated. Both spangle size and crystallographic orientation measured by optical microscopy, scanning electron microscopy, and X-ray diffraction were identified as critical factors influencing the galvanized coating performance. By decreasing the spangle size, surface appearance and galling properties related to the friction coefficient were significantly improved. However, low temperature adhesive-strength with small spangle galvanized steel sheets showed lower values compared to commercially used galvanized coating. The variation of adhesive strength in terms of spangle size has been clarified.

초극저탄소 Cu강화형 자동차용 강판 변형시효에 미치는 Aluminum 및 고용질소의 영향

홍문희 ( Moon Hi Hong ),양혜미 ( Hye Mi Yang ),송승우 ( Seung Woo Song ),한성호 ( Seong Ho Han ) 대한금속재료학회 2009 대한금속·재료학회지 Vol.47 No.2

용융아연 도금특성에 미치는 Mg 미량첨가 영향

홍문희 ( Moon-Hi Hong ),강덕구 ( Deok-Gu Kang ),백두진 ( Doo-Jin Paik ),황현석 ( Hyeon-Seok Hwang ),박성호 ( Sung-ho Park ) 대한금속재료학회(구 대한금속학회) 2016 대한금속·재료학회지 Vol.54 No.10

The effect of a small amount of added Mg on the microstructure. Fe-Al inhibition layer, corrosion resistance and welding properties of hot-dip galvanized and galvannealed steel sheets were investigated. Both the microstructure and distribution of Mg were measured by scanning election microscopy, transmission electron microscopy, glow discharge spectrometer and electron probe micro analyzer. A thin Mg layer was inhomogeneously precipitated between the Zn-coating and Al inhibition layer. During the annealing process around 470-510°C, the Mg layer was completely diffused into the inside and/or extreme surface of the Zn coating. The corrosion resistance of galvannealed steel sheets produced in a commercial galvanizing line was significantly improved by adding a small amount of Mg into the molten zinc pot. Fe content, the formation of the Fe-Al inhibition layer and weldability were also influenced by the Mg addition.

간호사의 의료기관인증제 인식, 감염관리 인지도 및 수행도

홍문희(Hong, Moon-Hee),박주영(Park, Ju-Young) 한국간호행정학회 2016 간호행정학회지 Vol.22 No.2

Purpose: This study was conducted to provide basic data necessary to develop a program to improve infection control by examining nurses" perception of accreditation and by identifying its relationship with awareness and performance of infection control. Methods: This cross-sectional study was performed using questionnaires. Data were collected from 210 nurses who were working at one hospital between May 14 and May 19, 2015. Data were analyzed using SPAW. Results: The mean score for nurses’ perception of accreditation was 3.10 points out of 5 points. Score for awareness of infection control was 4.63±0.39 points and for performance of infection control, 4.39±0.39 points. There were significant positive correlation among perception of accreditation, awareness of infection control, and performance of infection control. In the regression analysis, performance of infection control was influenced by awareness of infection control which accounted for 42.6% of the variance. It also showed additional improvement of 1.4% of the variance by when perception of accreditation was added. Conclusion: The result of this study show that nurses’ perception of accreditation is relatively positive and that performance of infection control is highly enhanced according to nurses" positive recognition of accreditation as well as attaching importance to accreditation.

일반논문 : 절충교역 계약 소요기간 영향요인

홍석수 ( Seok Soo Hong ),정태윤 ( Tae Yun Joung ),서재현 ( Jae Hyun Seo ),홍문희 ( Moon Hee Hong ) 기술경영경제학회 2012 Journal of Technology Innovation Vol.20 No.1

우리나라는 1983년에 절충교역 제도를 도입하여 국방 전력증강의 효율적 수단으로 활용하여 왔다. 그런데 절충교역은 계약체결이 획득기술에 대한 가치평가 결과를 근거로 이루어지기 때문에 국외업체와의 협상 등 업무과정상 지연될 가능성이 존재한다. 절충교역 계약체결이 지연되면 무기체계 구매사업이 늦어져 국방 전력증강에 심각한 악영향을 주게 된다. 따라서 본 연구에서는 절충교역 계약 과정, 특히 계약 소요기간에 영향을 미치는 요인들을 통계적으로 분석하여 소요기간을 결정하는 요인을 규명하고자 하였다. 영향 요인으로는 국외업체국적, 사업진행 형태 (경쟁/단독 입찰), 사업 특성 (최초/계속 사업), 최초 제안기술의 수, 국내무기체계 분야별 국방과학기술수준, 기본사업 규모 등 6개를 고려하였다. 가설 검증은 절충교역 계약이 체결된 25개 사업을 대상으로, 상관분석 및 다중회귀분석을 통하여 이루어졌다. 상관분석 결과에 의하면, 기본사업 규모, 최초 제안기술의 수, 사업 특성 등이 종속변수인 절충교역 계약 기간과 양의 상관관계를 갖고 있음을 알 수 있었다. 다중회귀분석 결과에서는 기본사업 규모와 사업진행 형태가 절충교역 계약 소요기간에 유의한 영향을 미치는 것으로 나타났다. Republic of Korea has been applying offset to defense acquisition program for some benefits such as modernization of defense industry and enhancement of R&D capabilities since 1983. But in point of implementation, there is the possibility of delay of offset agreements based on the value of proposed technologies. As it often happens that the delay of offset agreement negatively affects the time schedule of main defense deal, it is necessary to prepare for this issue. The purpose of this study is to extract some factors affecting the duration of offset agreement by statistical analysis. Reviewing existing papers and contract process, nationality of enterprise, the number of project participants, properties of project, the number of technologies in the first proposal, level of domestic defense technology in each weapons system, the amount of main contract were used as independent variable and duration of agreement as dependent variable. To hypothesis testing, correlation and multiple regression analysis were conducted using the previous 25 contract cases. As a result of correlation analysis, the amount of main contract, the number of technologies in the first proposal and properties of project have positive relationships with dependent variable. In multiple regression, the amount of main contract and the number of project participants have significant effect on the duration of offset agreement.