http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
김주한,이상재,오미경,강유성,Kim, Juhan,Lee, Sangjae,Oh, Mi Kyung,Kang, Yousung 한국전자통신연구원 2020 전자통신동향분석 Vol.35 No.1
Just as it is possible to distinguish people by using physical features, such as fingerprints, irises, veins, and faces, and behavioral features, such as voice, gait, keyboard input pattern, and signatures, the an IoT device includes various features that cannot be replicated. For example, there are differences in the physical structure of the chip, differences in computation time of the devices or circuits, differences in residual data when the SDRAM is turned on and off, and minute differences in sensor sensing results. Because of these differences, Sensor data can be collected and analyzed, based on these differences, to identify features that can classify the sensors and define them as sensor-based device DNA technology. As Similar to the biometrics, such as human fingerprints and irises, can be authenticatedused for authentication, sensor-based device DNA can be used to authenticate sensors and generate cryptographic keys that can be used for security.
합성가스 충돌제트화염에서 수소함량 증가에 따른 열음향 불안정성 - Part I : 자려진동에 의한 소음방사 특성
김주한(Juhan Kim),이기만(Keeman Lee) 한국연소학회 2021 한국연소학회지 Vol.26 No.1
In this study, various equivalence ratios and Reynolds numbers were used to investigate the thermo-acoustic instability in the impinging jet flame using syngas fuel. Various instability modes occurred in syngas of H2:CO=50:50 composition ratio, and this study focused on the description of the characteristic of each mode and tendency analysis. It was classified into 4 types of Regime by equivalence ratio and Reynolds number, that is, Regime II-1, II-2, II-3, and II-4 respectively. The shapes of the flame and the flow field in representative conditions of each regime were visualized, and the pressure fluctuation data were verified to be clearly different through various methods (FFT, phase portrait, recurrence plot). Also, there was a section in which the frequency and intensity of the noise decreased as the heat capacity(equivalent ratio or Reynolds number) increased, and it is another criterion for dividing the regime. Finally, the sensitivity was confirmed through the correlation between the two dominant frequencies (II-1, II-3) and Reynolds number, equivalence ratio.
Rapid Fabrication of Magnesium Hydroxide Layer on Magnesium Alloy to Improve Corrosion Resistance
김주한(JuHan Kim),박병락(Byungrak Park),황운봉(Woonbong Hwang) Korean Society for Precision Engineering 2019 한국정밀공학회지 Vol.36 No.5
A simple and rapid method of fabricating Mg(OH)2 layer by chemical immersion was developed to improve the corrosion resistance of the magnesium alloy AZ31. The fabricated surface was superhydrophobic with a self-assembled monolayer coating of silane. The surface characteristics were evaluated by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Photoelectron Spectroscopy (XPS). The average water contact angle and sliding angle were determined to be 160° and 7° respectively as a result of wettability test. Potentiodynamic polarization indicated that both Mg(OH)2 layer and the thin layer of air were effective in improving anti-corrosion. This method which is efficient with regard to time and cost would be useful for magnesium industries and its application
프랙탈 난류생성판을 갖는 V-shape 화염에서 난류 예혼합 화염 분석: Part. II 난류화염의 구조 특징
김주한(Juhan Kim),이기만(Keeman Lee) 한국연소학회 2021 한국연소학회지 Vol.26 No.3
This study focuses on the characteristics of turbulent flame structures in V-shape turbulent premixed flames to evaluate the turbulent combustion dynamics of fractal turbulence generator. The details of the non-reactive turbulent flow characteristics with the fractal turbulence plate were explained in the previous study of Part I. In this work, the integral length scale of non-reactive flow was additionally investigated to obtain a Borghi-Peters diagram. By comparing the Borghi-Peters diagram shown as a result of the non-reactive flow with the reaction OH-PLIF image, it was confirmed that the flame characteristics for each regime were well represented. Also, the irregular turbulence of premixed flame was quantitatively analyzed using the flame brush obtained by the mean progress variable method. As a result, the flame brush of the fractal turbulence generator was wider than the perforated plate and mesh type. Finally, it was found that the thickness and angle of the flame brush were proportional to the turbulence intensity and turbulent Reynolds number, which are dimensionless numbers of turbulent flow.
프랙탈 난류생성판을 갖는 V-shape 화염에서 난류 예혼합 화염 분석 : Part. Ⅲ 난류 연소속도
김주한(Juhan Kim),이기만(Keeman Lee) 한국연소학회 2021 한국연소학회지 Vol.26 No.4
This study focused on calculating the turbulent flame speed in a V-shape turbulent premixed flame using a circular fractal turbulence generator. In previous studies [Part. I turbulent flow characteristics in a Non-Reacting Field], [Part. II characteristics of turbulent flame structures], the non-reactive turbulent flow and turbulent flame structure for the V-shape flame of a fractal turbulence generator were investigated in detail. Two types of turbulent burning velocities are evaluated : local displacement and consumption speeds. The local consumption speed is calculated via the image processing of flame surface density. The results show that turbulent burning velocity increases much with fractal grids as compared with the conventional grids perforated plate and mesh. Finally, it was confirmed that the correlation between the turbulent flow factor and the two turbulent burning velocities of each turbulence generator was collapsed well with a specific correlation equation.