Photoresponsive characteristics and hysteresis of soluble 6,13-bis(triisopropyl-silylethynyl)-pentacene-based organic thin film transistors with and without annealing

Cho, Mi Yeon,Han, Yoon Deok,Kang, Han Saem,Kim, Kihyun,Kim, Kyung Hwan,Cho, Min Ju,Choi, Dong Hoon,Joo, Jinsoo American Institute of Physics 2010 JOURNAL OF APPLIED PHYSICS - Vol.107 No.3

Use of CFD Analyses to Predict Disk Friction Loss of Centrifugal Compressor Impellers

CHO, Leesang,LEE, Seawook,CHO, Jinsoo THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIEN 2012 Transactions of the Japan Society for Aeronautical Vol.55 No.3

<P>To improve the total efficiency of centrifugal compressors, it is necessary to reduce disk friction loss, which is expressed as the power loss. In this study, to reduce the disk friction loss due to the effect of axial clearance and surface roughness is analyzed and methods to reduce disk friction loss are proposed. The rotating reference frame technique using a commercial CFD tool (FLUENT) is used for steady-state analysis of the centrifugal compressor. Numerical results of the CFD analysis are compared with theoretical results using established experimental empirical equations. The disk friction loss of the impeller is decreased in line with increments in axial clearance until the axial clearance between the impeller disk and the casing is smaller than the boundary layer thickness. In addition, the disk friction loss of the impeller is increased in line with the increments in surface roughness in a similar pattern as that of existing experimental empirical formulas. The disk friction loss of the impeller is more affected by the surface roughness than the change of the axial clearance. To minimize disk friction loss on the centrifugal compressor impeller, the axial clearance and the theoretical boundary layer thickness should be designed to be the same. The design of the impeller requires careful consideration in order to optimize axial clearance and minimize surface roughness.</P>

Geometric Image Compensation Method for a Portable Projector Based on Prewarping Using 2D Homography

( Jinsoo Cho ),( Jongkil Won ),( Jongwoo Bae ) 한국인터넷정보학회 2013 KSII Transactions on Internet and Information Syst Vol.7 No.9

As portable multimedia devices become more popular and smaller, the use of portable projectors is also rapidly increasing. However, when portable projectors are used in mobile environments in which a dedicated planar screen is not available, the problem of geometric distortion of the projected image often arises. In this paper, we present a geometric image compensation method for portable projectors to compensate for geometric distortions of images projected on various types of planar or nonplanar projection surfaces. The proposed method is based on extraction of the two-dimensional (2D) geometric information of a projection area, setting of the compensation area, and prewarping using 2D homography. The experimental results show that the proposed method allows effective compensation for waved and arbitrarily shaped projection areas, as well as tilted and bent surfaces that are often found in the mobile environment. Furthermore, the proposed method is more computationally efficient than conventional image compensation methods that use 3D geometric information.

Fully Gravure-Printed Flexible Full Adder Using SWNT-Based TFTs

Jinsoo Noh,Kyunghwan Jung,Joonseok Kim,Sungho Kim,Sungho Cho,Gyoujin Cho IEEE 2012 IEEE electron device letters Vol.33 No.11

<P>A single-walled carbon nanotube (SWNT)-based 1-b full-adder circuit was realized on flexible plastic substrates through an all gravure printing process by minimizing intertransistor process variation and leakage current between crossing interconnects. The circuit comprised 27 printed SWNT thin-film transistors, with a variation of up to only ±25% in electrical characteristics among them. Furthermore, the circuit showed a maximum propagation delay of 13.7 ms, with a 50-Hz input signal, and a supply voltage of -20 V. The process could be used for low-cost flexible arithmetic logic units in a variety of applications.</P>

Chemistry and Design Considerations for Zinc Application Into Reactor Coolants of I-SMR

Jinsoo Choi,Daseul Ham,Cho-Rong Kim,Yong-Sang Cho,Hyuk-chul Kwon,Kyu-Min Song 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.1

Korean innovative SMR has been implemented developing with improved safety/economy and i- SMR technology development project to secure a competitive edge in SMR. For nuclear power plants, according to the revision of the Nuclear Safety Act (2013.6), it is mandatory to be reflected in the aging management program of nuclear power plants, and the aging management and regulation of major nuclear power plants are being strengthened. For i-SMR, chemistry environment and management strategy is essential to mitigate corrosion and radiation fields, since it has compacted and integrated module designs. Since 1994, zinc injection into the reactor coolant system (RCS) has been applied more than 100 PWRs in the world to mitigate primary water stress corrosion cracking (PWSCC) and to reduce outof- core radiation fields. In domestic NPPs, 7 have been applying zinc injection and had up to 90% radiation field reductions. For this reason, SMR needs to apply zinc injection for chemistry strategy. Zinc target concentration will be 5~40 ppb at i-SMR, based on Ni-Fe-Cr materials as same as PWRs. Zinc injection location is in volume and purification control system between the volume control tank and charging P/P where the pressure is moderate. Zinc injection skid can consist of two micro-controllable pump (one for operation and one for stand-by) and one injection tank (batching tank for zinc solution). Zn, Ni, Si, Fe, and activated corrosion products should be monitored to identify zinc injection controls and trends. Flux mapping for core performance monitoring should be evaluated. The application of zinc will be essential and effective and bring sustainable reliability for corrosion control and mitigation strategy to meet the risk-free i-SMR development.

비선형 필터 기반의 적응적 슈트제거 방법

조진수(Jinsoo Cho),배종우(Jongwoo Bae) 대한전자공학회 2008 電子工學會論文誌-SC (System and control) Vol.45 No.2

TV를 포함하는 최근의 디스플레이 시스템들은 디지털화 및 대형화 되는 추세이며, 이러한 시스템들의 화질은 현재의 디스플레이 시스템 시장에서 매우 중요한 상품 경쟁력의 하나로 인식되고 있다. 이에 디지털 디스플레이 시스템의 화질을 개선하기 위한 다양한 연구들이 진행되어 왔다. 선명도 개선 기술은 디지털 영상(혹은 동영상)의 화질개선을 위한 중요한 기술들 중 하나로서, 일반적으로 영상경계(edge)의 천이시간(transition time)을 줄여 주는 천이향상(transient improvement) 기술을 기반으로 하고 있다. 하지만, 이 기술은 흔히 천이가 향상된 영상경계 주변에 원치 않는 휘도(혹은 색차)의 변화를 가져올 수 있는 오버슈트(overshoot) 및 언더슈트(undershoot) 현상을 발생시킨다. 이에 본 논문에서는 천이향상 시 발생하는 오버슈트 및 언더슈트를 효과적으로 제거하여 시각적으로 보다 선명하고 깨끗한 디지털 영상(혹은 동영상)을 얻기 위한 새로운 방식의 비선 형 필터 기반의 적응적 슈트제거 방법(nonlinear filter-based adaptive shoot elimination method)을 제안한다. 제안한 방법은 두 가지 직교 방향(orthogonal directional)의 최소/최대 비선형 필터들과 적응적 슈트제거 방식을 적용하여 시각적으로 민감한 오버슈트 및 언더슈트를 효과적으로 제거한다. 실험을 통하여, 제안한 방법이 영상경계의 천이향상 정도는 그대로 유지하면서 영상의 왜곡을 초래하는 오버슈트 및 언더슈트를 거의 완벽하게 제거한다는 것을 보여 주었다. 제안한 방법이 적용될 수 있는 제품들로는 디지털 TV, 디지털 모니터, 디지털 카메라/캠코더, 휴대형 멀티미디어 플레이어(PMP) 등이 있다. The current display systems including TVs are going digital and large-sized, and high visual quality of those systems becomes a very important selling point in the current display system market. Thus, various researches have been carried out for enhancing the visual quality of digital display systems. One of the important digital image(or video) enhancement techniques is sharpness enhancement, and it is generally based on a transient improvement technique that reduces the edge transition time. However, this technique often generates overshoot and undershoot, which cause undesirable pixel-level changes around the transient improved edge. In this paper, we propose a new nonlinear filter-based adaptive shoot elimination method for effectively suppressing the overshoot and undershoot that occur in the transient improvement, so that we can obtain visually sharper and clearer digital images(or videos). The proposed method uses two orthogonal directional min/max nonlinear filters with an adaptive shoot elimination scheme in order to effectively suppress the visually sensitive overshoot and undershoot. Experimental results show that the proposed method suppresses the overshoot and undershoot almost perfectly while maintaining the effect of the transient improvement. The applications of the proposed method include digital TVs, digital monitors, digital cameras/camcoders, portable media players(PMP), etc.

효율향상을 위한 프로펠러 형상의 최적설계

조진수(Jinsoo Cho),이승철(Seoung-chul Lee) 한국항공우주학회 1996 韓國航空宇宙學會誌 Vol.24 No.4

광열 소재 일체형 태양열 막증류 시스템의 공정 구성별 효율 평가

조진수 ( Jinsoo Cho ),최지혁 ( Jihyeok Choi ),차호영 ( Hoyoung Cha ),정진호 ( Jinho Jung ),송경근 ( Kyung Guen Song ) 한국물환경학회 2023 공동춘계 학술발표회 논문집 Vol.2023 No.0

북한에서의 학교체육을 통한 학생의 몸의 통제

조진수(Cho, Jinsoo) 한양대학교 평화연구소 2017 문화와 정치 Vol.4 No.3

국가재건 시기에 북한은 소비에트식 모델로 빠르게 사회주의 국가를 건설하고자 했다. 이러한 사회주의의 근대적 기획은 교육 분야에서도 적용되어 사회주의 교육체계가 빠르게 정립되었다. 사회주의 교육의 목표는 사회주의 인간형의 창출이다. 이를 위해 다양한 교육시스템의 정비가 이루어졌는데 특히 사회주의 교육의 특징이라고 할 수 있는 체육교육의 강화가 북한교육에서도 이루어졌다. 본 연구는 1950년대 국가재건 시기에 북한이 새로운 사회주의 인간형을 창출하기 위해 학생의 몸을 규율하고 통제하기 위한 수단으로 학교체육에 개입한 이유와 이때 활용된 전략을 생명관리정치의 규율권력기제를 사용하여 분석하였다. From the beginning of modern society, the politics of disciplinary power has tried to control the human body as a crucial way to rule the society as a whole. This is the crucial meaning of biopolitics that seems to have worked in the social context of the liberal government. In its national reconstruction period (1953-1960), however, the North Korean government used the bio-politics in a radical way in order to construct a socialist state as quickly as possible based upon the Soviet system. After the Korean War, North Korea strengthened the educational policy of the physical exercise since schools were the most crucial places for controlling the bodies of people. The purpose of this article is to show that the disciplinary power of North Korea can be found in various forms of the educational method of physical exercises. The modern socialist regime of North Korea in 1950s attempted to create a new type of the socialist man by primarily controlling the students’ bodies.

Aerodynamic Design and Analysis of a Propeller for a Micro Air Vehicle

Leesang Cho,Jaemin Yoon,Cheolheui Han,Jinsoo Cho 대한기계학회 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.10

A U-80 propeller and its modified version, U-75 propeller, are used for a micro air vehicle. The performance characteristics of a U-80 propeller and a U-75 propeller have not much known in the published literature. Thus, their aerodynamic characteristics are investigated using a lifting surface numerical method. The lifting surface method is validated by comparing computed results with measured data in a wind tunnel. From the computed results, it is found that the U-75 propeller produces larger thrust with higher efficiency than the U-80 propeller. To enhance the performance of these propellers, a new propeller is designed by following the sequential design procedures with the design parameters such as hub-tip ratio, maximum camber and its position, and chord length distribution along the radial direction. The performance of the designed propeller is shown to be improved much comparing with those of both the U-80 and U-75 propellers.