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가진 펌프에 연결된 곡관 출구의 직관에서 난류진동유동의 속도분포와 전단응력분포
손현철,이행남,박길문 대한기계학회 2002 大韓機械學會論文集B Vol.26 No.10
In the present study, velocity profile and wall shear stress distributions of developing turbulent oscillatory flows in an oscillator connected to straight duct located in exit region of a curved duct was investigated experimentally. The experimental study for air flows was conducted to measure axial velocity profiles, shear stress distributions by using the Laser Doppler Velocimetry(LDV) system with the data acquisition and processing system of Rotating Machinery Resolver(R.M.R) and PHASE software. The results obtained from experimental studies are summarized as follows. The critical Reynolds number for a change from transitional oscillatory flow to turbulent flow was about 7500, in the 60region of dimensionless axial position which was considered as a fully developed flow region. The turbulent oscillatory flow, velocity profiles of the inflow period in the entrance region were gradually developed, but those of the outflow period were not changed nearly. Velocity profiles of inflow and outflow were shown as a symmetric form in a fully developed flow region. The wall shear stress distributions of turbulent oscillatory flow increase rapidly as the flow proceeds to downstream and flow was in good agreement with the theoretically.
曲管덕트 입구 영역에서 遷移定常流動의 速度分布와 壁面剪斷應力分布에 관한 연구
손현철,김명호,박길문 朝鮮大學校 機械技術硏究所 1998 機械技術硏究 Vol.1 No.1
In the present study, the flow characteristics of developing transitional steady flows in a square - sectional 180° curved duct are investigated experimentally. The experimental study for air flow in a square - sectional 180° curved duct is carried out to measure the axial velocity profiles and wall shear stress distributions by using Laser Doppler Velocimeter (LDV) system with data acquisition and processing the system of FIND software at 7 sections from the inlet (ø=0°) to the outlet (ø=180°) in 30° intervals of a curved duct. The results obtained from experimental studies are summarized as follows : (1) The critical Dean number of transitional steady flow is about 450. They show that critical Reynolds number in a curved duct is larger than that in a straight duct. (2) For transitional steady flows, the maximum velocity position of axial velocity profiles begins to incline toward the outer wall from ø=30°bended angle, velocity profiles in center of the duct have lower value than those of the inner and outer walls because of the centrifugal forces. (3) Wall shear stress distributions of transitional steady flows are increased at the entrance region because of increasing shear stress and pressure loss by the influence of flows.
곡관덕트에서 난류정상유동의 벽면전단응력분포와 입구길이에 관한 실험적 연구
손현철,이홍구,김대욱,김명호,박길문 朝鮮大學校 機械技術硏究所 2000 機械技術硏究 Vol.3 No.1
In this paper, an experimental investigation of characteristics of developing turbulent steady flows in a square-sectional 180°curved duct is presented. The experimental study using air in the square-sectional 180°curved duct is carried out to measure entrance length and wall shear stress distributions by using Laser Dopper Velocimeter(LDV) system with data acquisition and processing the system of FIND6260 software at 7 sections from the inlet(ø=0°) to the outlet(ø=180°)in 30°intervals of the curved duct. The results obtained from experimental studies are summarized as follows : (1) The critical Dean number of turbulent steady flow is about 560. (2) The value of the wall shear stress becomes minimum in the inner wall and gradually increases toward the outer wall where it becomes maximum. (3) The entrance length of the turbulent steady flow is shorter than that of the traditional steady flow, reaching the vicinity of bend angle 90°
손현철,김경진 한국구조생물학회 2017 Biodesign Vol.5 No.2
meso-Diaminopimelic acid decarboxylase from Corynebacterium glutamicum (CgDAPDC) is the key enzyme for theproduction of L-lysine and it catalyzes meso-DAP to produce the final product, L-lysine. The CgDAPDC was overexpressedand purified to homogeneity by Ni-NTA affinity and size-exclusion chromatography. The CgDAPDC protein was crystallizedusing sitting-drop vapor-diffusion method in the presence of 0.8 M sodium citrate tribasic and 0.1 M sodium cacodylate,pH 6.5 at 293 K. X-ray diffraction data were collected to a maximum resolution of 2.4 Å. The crystal belonged to spacegroup P21212, with unit cell parameters a = 114.54 Å, b = 91.702 Å, c = 95.161, α = β = γ = 90°. With one molecules perasymmetric unit, the crystal volume per unit protein mass was 2.64 Å3 Da-1, which correspond to a solvent content ofapproximately 53.37%.
손현철(HyeonCheol Son),김성영(SungYoung Kim) 한국정보기술학회 2021 Proceedings of KIIT Conference Vol.2021 No.11
태양광 패널의 불량은 그 특성으로 인해 열을 발산하여 높은 온도를 가진다. 따라서 열화상 카메라로 패널의 열을 촬영하고 열화상 영상으로 태양광 불량을 분류하는 네트워크를 제안한다. 열화상 영상은 그 자체로 특징을 나타내기 때문에 Residual block을 이용해 입력데이터의 Identity를 보존하는 과정을 포함한다. 네트워크의 분류 정확도는 57.14%로 향후 데이터의 많은 수집을 통해 정확도 향상을 기대해 볼 수 있다. The defect of the solar panel has a high temperature by dissipating heat due to the characteristics of the defect. Therefore, photographing heat of a panel with thermal imaging camera and a network that classifying solar defects into thermal imaging images is proposed. Since thermal images themselves represent characteristics, they include the precess of preserving the identity of input data using Residual block. The proposed network classification accuracy is 57.14%, which can be expected to improve accuracy through a large collection of data in the future.
손현철(Hyeon-Cheol Son),김호한(Ho-Han Kim),김성영(Sung-Young Kim) 한국정보기술학회 2019 Proceedings of KIIT Conference Vol.2019 No.6
본 논문에서는 자신의 골프 동작을 프로 골프의 동작과 비교하여 골프 자세를 교정하는 방법을 개발하였다. 이를 위해 특정 골격 지점에 대한 위치 변화 그래프 view, 2D View, data view, 교정사항 view의 6가지의 뷰화면을 제공하여 프로그램을 개발하여 원본군(자신의 골프 동작)과 대조군(프로 골퍼 골프 동작) 사이의 동작비교가 가능하도록 한다. 본 논문에서 제안하는 방법은 키넥트를 통해 실시간으로 촬영되는 움직임에 대한 골격 정보와 깊이 정보를 사용하여 골프 자세 구간을 4구간으로 구분하여 비교에 사용한다. 뿐만 아니라, Openpose를 사용하여 기존에 녹화된 비디오 영상으로부터 골격 정보를 생성하여 사용하는 것이 가능하도록 한다. 분석한 정보를 바탕으로 자신의 골프 자세와 프로 골퍼의 자세 간의 거리, 각도, 몸의 중심, x-factor에 대한 데이터를 비교하여 제공함으로써 자세 분석이 가능하도록 하였다. In this paper, we developed a method to correct the golf posture by comparing the golf motion of a golfer with the motion of the pro-golfer. To do this, we provide a program with six views of the position change graph for a specific skeleton point, 2D view, data view, and correction view, and with comparing the motion between the original group (own golf action) and the control group (professional golfer golf action). The method proposed in this paper uses skeleton information and depth information for motion captured in real time through Kinect and divides the golf posture into four sections and uses it for comparison.In addition, it is possible to generate and use skeleton information from existing video images using Openpose. Based on the analyzed information, the posture analysis is made possible by comparing the data of distance, angle, body center, and x-factor between a golfer’s position and the professional golfer"s posture.