http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
손지하,오명훈,송인범,조경식,박용일,홍재근,박노광 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.
The aim of this study was to determine the effect of particle size distribution on the microstructure and mechanical properties of sparkplasma-sintered titanium made from commercial pure titanium (CP-Ti) powders. The spark plasma sintering (SPS) of 100-mesh, 200-mesh, 325-mesh CP-Ti powders and mixtures thereof (100-mesh and 325-mesh powders mixed in weight ratios of 3:7, 5:5, and 7:3)was carried out in a flowing atmosphere of Ar + H2 gas at 800~850oC under a pressure of 30 MPa. Dense titanium with a relativedensity of up to 99% was found to form for SPS conditions of over 850oC and 30 MPa. The sintered body showed a difference insintered properties depending on the particle size of the powder: the smaller the particle size, the more rapid the densification, andin terms of the grain size of the sintered body, equiaxed grain of about 20~40 μm in diameter was formed regardless of the particlesize distribution of the powder. Regarding the hardness and tensile properties in the fully densified sintered body, smaller averageparticle sizes gave rise to higher values because of the increase in the content of interstitial solid solution and the formation of ahomogeneous and fine-grained structure through the rapid densification process.
연도별 신조선 주요제원의 변화를 통한 대형화 추세 분석
손우주,구정민,문지하,조명환,조익순 한국항해항만학회 2023 한국항해항만학회 학술대회논문집 Vol.2023 No.1
대형 컨테이너 선박의 주요 제원 예측에 관한 과거 연구는 단순 회귀분석에 기반한 결과로 제시되었으며, 이를 현재 운항 중인24,000TEU급 선박의 제원과 과거의 연구 결과를 비교할 경우, 선박의 전장이 과대 예측한 경향이 있었다. 본 연구에서는 선형회귀분석 및box plot의 통계 분석기법을 활용하여 최근 20년의 신조 컨테이너선을 대상으로 연도별 주요제원의 변화량을 통해 선박의 대형화 추세를 분석하였다. 그 결과, 컨테이너선의 대형화는 시간의 흐름에 따라 점점 폭이 넓어지는 형태로 변화하고 있는 것으로 분석되었다. 그러나 선폭위주의 대형화는 선박 운항의 측면에서 조종성능의 감소로 인해 운항난이도가 증대된다는 단점이 있다. 즉, 미래 대형화 선박을 안전하게 운항하기 위해서는 적절한 항만 인프라 구축 및 선박길이와 폭의 조화를 이루는 대형화가 필요할 것으로 판단된다.
최적 교통분포를 고려한 해상교량의 안전 통항 폭에 관한 연구
손우주,문지하,구정민,조익순 한국항해항만학회 2022 한국항해항만학회지 Vol.46 No.4
Bridges across waterways act as interference factors, that reduce the navigable water area from the perspective of navigation safety. To analyze the safety navigational width of ships navigating bridges across waterways, the optimal traffic distribution based on AIS data was investigated, and ships were classified according to size through k-means clustering. As a result of the goodness-of-fit analysis of the clustered data, the lognormal distribution was found to be close to the optimal distribution for Incheon Bridge and Busan Harbor Bridge. Also, the normal distributions for Mokpo Bridge and Machang Bridge were analyzed. Based on the lognormal and normal distribution, the analysis results assumed that the safe passage range of the vessel was 95% of the confidence interval, As a result, regarding the Incheon Bridge, the difference between the normal distribution and the lognormal distribution was the largest, at 64m to 98m. The minimum difference was 10m, which was revealed for Machang Bridge. Accordingly, regarding Incheon Bridge, it was analyzed that it is more appropriate to present a safety width of traffic by assuming a lognormal distribution, rather than suggesting a safety navigation width by assuming a normal distribution. Regarding other bridges, it was analyzed that similar results could be obtained using any of the two distributions, because of the similarity in width between the normal and lognormal distributions. Based on the above results, it is judged that if a safe navigational range is presented, it will contribute to the safe operation of ships as well as the prevention of accidents. 해상교량은 선박의 통항 안전성 관점에서 가항수역을 줄이는 간섭요인으로 작용한다. 본 연구에서는 선박의 안전한 통항을 위해 최적 통항분포에 기반한 안전 통항폭을 분석하였다. 해상교량을 통항하는 선박의 안전 통항 폭에 대한 분석을 위해 AIS data에 기반한 선박 교통분포를 조사하여 K-means clustering을 통해 선박을 크기에 따라 분류하였다. 군집화된 데이터에 대하여 최적분포 분석을 한 결과, 인천대교와 부산항대교에서는 대수정규분포, 목포대교와 마창대교에서는 정규분포가 최적분포에 가까운 것으로 분석되었다. 대수정규분포와 정규분포를 기준으로 선박 안전 통항 범위를 신뢰구간의 95%로 가정하여 분석한 결과, 인천대교의 경우 정규분포와 대수정규분포 간의 차이가 64~97m로 가장 큰 것으로 나타났으며, 최소 차이는 10m로 마창대교에서 나타났다. 이에 따라, 인천대교의 경우에는 정규분포보다 대수정규분포로 안전 통항 폭을 제시하는 것이 적합한 것으로 분석되었다. 타 교량의 경우에는 정규분포와 대수정규분포 간의 통항 폭 차이가 크지 않기 때문에 둘 중 어떤 분포를 사용해도 유사한 결과를 얻을 수 있는 것으로 분석되었다. 위 결과를 토대로, 해상교량의 안전통항 범위를 제시한다면 선박의 안전한 운항 및 사고 예방에 도움이 될 것이다.
스크린 프린팅법에 의한 탄소나노튜브 전계방출소자의 제조기술
이만,손지하,주학림,정효수,고남제,이동구,Yi, Mann,Son, Ji-Ha,Chu, Haang-Rhym,Jeong, Hyo-Soo,Koh, Nam-Je,Lee, Dong-Gu 한국재료학회 2002 한국재료학회지 Vol.12 No.6
The carbon nanotube emitters for field emission displays were fabricated by using screen printing techniques. The pastes for screen printing are composed of organic binders, carbon nanotubes (multiwalled or singlewalled), and some additive materials. The pastes were printed on Cr-coated/Ag-printed soda-lime glass substrates. From the I-V characteristics, the turn-on field of SWNT was lower than that of MWNT. The decrease in the mesh size of screen masks (i.e. increase in the opening size of the screen mesh) resulted in decreasing the turn-on field and increasing the electron emission current. When the carbon nanotubes were mixed with silver pastes, silver powders appeared to contribute to the vertically aligning of carbon nanotubes on a glass.
도영수 ( Young Su Do ),손지하 ( Je Ha Shon ),박노진 ( No Jin Park ),박용일 ( Yong Il Park ),최환 ( Hwan Choi ),오명훈 ( Myung Hoon Oh ) 한국열처리공학회 2013 熱處理工學會誌 Vol.26 No.3
In this study, effects of silicon addition on the spheroidizing annealing of hyper-eutectoid steel was investi-gated,Heat treatment at various temperatures in they +θ region was also conducted in order to systematically control the kinetics of undissolved cementite. It was found that amount of Si addition could increase both A1 and Acm transformation temperature by both the JMat Pro evaluation and dilatometric measurement. It was also revealed by the microstrural observation that the volume fraction of retained cementite during heat treatment increased with decreasing temperature as well as increasing Si content. Based on the results obtained, it could be suggested that sphe-roidization at relatively higher temperature above 950℃ could be achieved by small addition of Si. (Receivied March 19, 2013, Revised April 25, 2013; Accepted May 19, 2013)
전해질 연료전지용 복합분리판의 특성에 미치는 TiB 2 첨가효과
박종문 ( Jong Moon Park ),손지하 ( Je Ha Sohn ),박용일 ( Yong Il Park ),이동구 ( Dong Gu Lee ),오명훈 ( Myung Hoon Oh ) 한국열처리공학회 2014 熱處理工學會誌 Vol.27 No.4
The effect of varying amounts of graphite and TiB2 on the electrical conductivity of composite bipolarplates was systematically studied. In this study, Titanium diboride (TiB2) which has a high electrical conductivity,was selected as a filler and a additive material instead of conventional graphite. For proper distribution of the fillerand matrix materials, ball milling using alumina balls was conducted for 1h, and then the hot press method wasapplied for the preparation of composite samples. The results showed a rapid increase in the electrical conductivityof composite bipolar plates at the critical filler content. However, TiB2 and graphite composite bipolar platesshowed similar increases in the electrical conductivity even though TiB2 has a higher electrical conductivity thangraphite. In addition, it was also found that a small addition of TiB2 to graphite filler could be very effective forincreasing the electrical conductivity and flexural strength of the composite bipolar plate.
김동욱(Dong Wook Kim),김종식(Jong Sik Kim),박병호(Byung Ho Park),손지하(Je Ha Shon),이진현(Jin Hyeon Lee) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11
A circular saw is a machine using a toothed metal cutting disc or blade. This study is to investigate the dynamic characteristics of circular sawing machine. For the dynamic analysis of the machine system, the modal and frequency response analysis are carried out using finite element method based on the three-dimensional solid model. Analysis results are used to evaluate vibration stability of the circular sawing machine.