우리시대 사진의 상황 : Magic Space ( 이현호 )

이현호 현대사진영상학회 1998 우리시대 사진의 상황 Vol.- No.-

갓김치에서 분리한 NaCl 및 캡사이신 내성 세균인 Bacillus amyloliquefaciens G-13의 혈전용해활성

이현호,석지원,오계헌 한국생물공학회 2019 KSBB Journal Vol.34 No.3

The purpose of this work was to investigate thefibrinolytic activities of NaCl- and capsaicin-resistant bacterium,Bacillus amyloliquefaciens G-13 isolated from fully fermentedmustard leaf kimchi. Initially, the physiological andbiochemical characteristics of strain G-13 were examined. 16SrRNA sequencing analysis was performed to identify the strain,and the strain was designated as B. amyloliquefaciens G-13. B. amyloliquefaciens G-13 grew well in the different concentrationsof NaCl (1-10%) and capsaicin (0-300 μg/mL) at 37oC. B. amyloliquefaciens G-13 showed the strongest fibrinolyticactivity (3.42 unit/mL) in the absence of NaCl and capsaicin. When B. amyloliquefaciens G-13 was cultivated in harsh conditions,such as in LB media containing 10% NaCl and 300 μg/mLcapsaicin, the culture showed 0.74 unit/mL of fibrinolyticactivity for 84 h. To our knowledge, this is the first report ofthe fibrinolytic activities of NaCl- and capsaicin-resistant bacteriumisolated from kimchi, including mustard leaf kimchi. Considering its high fibrinolytic activity and significant NaClandcapsaicin-resistance, B. amyloliquefaciens G-13 can beused as a starter culture for various food fermentations.

웹 커뮤니티 - 웹 커뮤니티 시스템 모델링(1)

이현호,Lee, Hyeon-Ho 한국데이터베이스진흥원 2002 디지털콘텐츠 Vol.1 No.-

슬릿형상에 따른 강재댐퍼의 이력거동

이현호,김세일 한국구조물진단유지관리공학회 2011 한국구조물진단유지관리공학회 논문집 Vol.15 No.5

본 연구의 목적은 강재댐퍼 면내에 형성되는 슬릿 형상이 댐퍼의 강도 및 변형 능력에 미치는 영향을 평가하는데 있다. 이를 위하여 댐퍼 스트럿의 높이 및 각도에 대한 실험체 12개를 만들어 전단실험을 수행하였다. 분석결과, 댐퍼의 초기강성, 항복강도 및 항복 후 2차강성의 크기를 고려할 때 스트럿 높이가 200mm이고, 스트럿 각도 60°인 S형 강재댐퍼의 내진성능이 가장 우수한 것으로 평가되었다. 또한 기존내력식을 이용한 댐퍼의 항복강도 비교결과, 내력식의 결과보다 실험 결과값이 크게 나와 댐퍼의 항복강도는 스트럿높이, 스트럿각도 등의 크기정도에 지배 받는 것으로 나타났다. The purpose of this study is to evaluate of the strength and deformation capacity of metallic dampers with the variable slit shape. For this purpose, 12 metallic damper specimens were prepared and shear testing was performed. According to the test results, the S shaped metallic damper with the strut height of 200mm and angle of 60° shows better hysteretic performance than any other specimens. By making a comparison between the yield strength in test and the proposed strength formula, test results shows larger yield strength than calculation method.

Phosphate Associated Cadmium Immobilization Mechanism Depending on the Original Concentration of Cd in Soil

이현호,홍창오 한국토양비료학회 2016 한국토양비료학회지 Vol.50 No.4

Adsorption and precipitation of cadmium (Cd) could be dependent on rate of P addition and Cd level in soil. Therefore, the objective of this study was to examine how addition rate of P affect mechanisms of Cd immobilization such as adsorption and precipitation in different levels of Cd in soil. Arable soils were spiked with inorganic Cd (CdCl2) to give a total Cd concentration of 10, 100, and 1,000 mg Cd kg-1. Monopotassium phosphate (KH2PO4, MPP) was selected as phosphate material and mixed with the pretreated arable soil at the rates of 0, 800, 1,600 and 3,200 mg P kg-1. The mixture soils were incubated at 25°C for 8 weeks in dark condition. Soil pH decreased with increasing MPP addition rate in all levels of Cd but negative charge of soil increased, thereby reducing 1 M NH4OAc extractable Cd. Soil solutions were undersaturated with respect to CdCO3 and Cd3(PO4)2 with all P addition rate in soil with low Cd level (≤ 100 mg Cd kg-1) but supersaturated in soil with high Cd level (1,000 mg Cd kg-1). From the above results, Cd solubility was controlled by precipitation of Cd minerals such as CdCO3 and Cd3(PO4)2 in soil with high Cd level but by Cd adsorption induced by increase in negative charge of soil with low level of Cd.

Effect of thermally stable metal nenoparticles as compatibilizers on rheological and thermal properties of homopolymer blends

이현호 한국고분자학회 2010 한국고분자학회 학술대회 연구논문 초록집 Vol.2010 No.10

Surface Coverage Enhancement of a Mixed Halide Perovskite Film by using an UV-Ozone Treatment

이현호,Seunghyun Rhee,Jaeyoul Kim,Changhee Lee,김혁 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.3

Recently, a significant breakthrough in emerging photovoltaics occurred. Now, perovskite solar cells, hybrid types of organic and inorganic solar cells, are considered as reliable next-generation solar cells due to their outstanding photovoltaic performance. Records of the National Renewable Energy Laboratory (NREL) on cell efficiency research indicates a prominent growth in the power conversion efficiency (PCE) of a perovskite solar cells which is now approaching 20.1%. Perovskite solar cells are, in general, classified into three types based on their structures; the mesoporous type with TiO2 nanoparticles, the meso-superstructure type with Al2O3 and the planar hetero-junction type. Among them, planar-structured perovskite solar cells have strong advantages due to their easy processibility and flexibility. We can replace the materials in the electron transport layer (ETL) and the hole transport layer (HTL) with common materials that are available in organic solar cells. However, a great challenge is to fabricate a high-quality perovskite film because the perovskite morphology is highly sensitive to its fabrication conditions. For control of the film’s morphology, some experiments, such as changing the annealing temperature or time and adding some additives, have been done to increase the surface coverage of perovskite films. In this work, we introduce normal, planar, perovskite solar cells with a hetero-junction structure based on compact TiO2 and a mixed halide perovskite (CH3NH3PbI3−xClx). To enlarge the surface coverage of perovskite film, we used an UV-ozone treatment on top of the compact TiO2, which made the surface of TiO2 hydrophilic. Because a perovskite precursor is hydrophilic, an UV-ozone treatment is expected to improve the wettability between the compact TiO2 and the perovskite film. Here, we present the photovoltaic performance, along with the surface coverage difference, for various UV-ozone treatment time. In addition, the effect of the UV-ozone treatment was examined by using an opto-electronic analysis.

수치 모델을 이용한 2022년 8월 집중호우 사례의 미세물리적 특성 분석

이현호 한국기상학회 2022 한국기상학회 학술대회 논문집 Vol.2022 No.10

꺽쇠형 강재 댐퍼의 변위 및 속도 의존성

이현호 한국구조물진단유지관리공학회 2013 한국구조물진단유지관리공학회 논문집 Vol.17 No.2

본 연구의 목적은 일자형 슬릿형 강재댐퍼보다 에너지 소산능력 등이 우수할 것으로 평가된 꺽쇠형 강재 댐퍼의 변위 및 속도의존성 평가에 있다. 이를 위하여 6개의 시험체를 대상으로 의존성 시험을 수행하였다. 시험변수는 변위의존성 및 속도의존성이다. 변위의존성 시험결과, 큰 목표변위 (50mm)의 반복횟수 및 누적에너지소산능력은 적은 목표변위 (25mm)에 비하여 감소하였다. 또한 짧은 목표변위보다 큰 항복강도 및 조기파단을 나타내었다. 속도의존성 평가에서는 빠른 목표속도(60mm/sec)의 반복횟수 및 누적에너지소산능력이 느린 목표속도 (40mm/sec)에 비하여 감소하였다. 따라서 강재댐퍼의 이력 의존성은 가력 변위 및 속도와 밀접한 연관이 있는 것으로 평가되었다. The purpose of this study is the displacement and velocity dependence evaluation of clamped shape metallic damper, which were evaluated superior in energy dissipation capacity than straight type slit damper. For this purpose, 6 metallic damper specimens are prepared and dependence test are performed. Test variables are displacement dependence and velocity dependence. According to displacement dependence test results, larger target displacement (50mm) shows lower cyclic numbers and cumulated energy dissipated area than lower target displacement (25mm). Also it shows higher strength and early failure than short target displacement. In velocity dependence evaluation, fast target velocity (60mm/sec) shows lower cyclic numbers and cumulated energy dissipated area than slow target velocity (40mm/sec). Therefore the hysteresis dependence of metallic damper were evaluated as close relation to the loading displacement and velocity conditions.

비선형 대기 모형에서 수치 해의 시간 간격 민감도

이현호,백종진,한지영 한국지구과학회 2013 한국지구과학회지 Vol.34 No.1

An appropriate determination of time step is one of the important problems in atmospheric modeling. In this study, we investigate the sensitivity of numerical solutions to time step in a nonlinear atmospheric model. For this purpose, a simple nondimensional dynamical model is employed, and numerical experiments are performed with various time steps and nonlinearity factors. Results show that numerical solutions are not sensitive to time step when the nonlinearity factor is not influentially large and truncation error is negligible. On the other hand, when the nonlinearity factor is large (i.e., in a highly nonlinear regime), numerical solutions are found to be sensitive to time step. In this situation, smaller time step increases the intensity of the spatial filter, which makes small-scale phenomena weaken. This conflicts with the fact that smaller time step generally results in more accurate numerical solutions owing to reduced truncation error. This conflict is inevitable because the spatial filter is necessary to stabilize the numerical solutions of the nonlinear model. 대기 모델링 연구에서 시간 간격을 적절하게 결정하는 것은 중요한 문제이다. 본 연구에서는 비선형 대기 모형에서 수치 해의 시간 간격에 대한 민감도를 조사하였다. 이를 위해 간단한 무차원화된 역학 모형을 사용하여 시간 간격과 비선형성 인자를 바꾸어가며 수치 실험을 수행하였다. 실험 결과, 비선형성 인자가 영향을 줄 만큼 크지 않고 절단 오차를 무시할 수 있는 경우에는 수치 해가 시간 간격에 민감하지 않았다. 그러나 비선형성 인자가 큰 경우에는 수치 해가 시간 간격에 민감한 것으로 밝혀졌다. 이 경우, 시간 간격이 감소할수록 공간 필터의 강도가 증가하여 작은 규모의 현상이 약하게 모의되었다. 이는 일반적으로 시간 간격이 감소하면 절단 오차가 감소하여 더 정확한 수치 해가 도출된다는 사실과 상충한다. 이러한 충돌은 비선형 모형의 수치 해를 안정하게 하기 위해 공간 필터가 반드시 필요하기 때문에 피할 수 없다.