Sol-gel 법을 이용한 내오염 반사방지 코팅막 제조

김정엽,이지선,황종희,임태영,이미재,현승균,김진호,Kim, Jung-Yup,Lee, Ji-Sun,Hwang, Jonghee,Lim, Tae-Young,Lee, Mi-Jai,Hyun, Soong-Keun,Kim, Jin-Ho 한국재료학회 2014 한국재료학회지 Vol.24 No.12

Anti-reflection coating films have used to increase the transmittance of displays and enhance the efficiency of solar cells. Hydrophobic anti-reflection coating films were fabricated on a glass substrate by sol-gel method. To fabricate an anti-reflection film with a high transmittance, poly ethylene glycol (PEG) was added to tetraethyl orthosilicate (TEOS) solution. The content of PEG was changed from 1 to 4 wt% in order to control the morphology, thickness, and refractive index of the $SiO_2$ thin films. The reflectance and transmittance of both sides of the coated thin film fabricated with PEG 4 wt% solution were 0.3% and 99.4% at 500 nm wavelength. The refractive index and thickness of the thin film were n = 1.29 and d = 105 nm. Fluoro alkyl silane (FAS) was used for hydrophobic treatment on the surface of the anti-reflection thin film. The contact angle was increased from $13.2^{\circ}$ to $113.7^{\circ}$ after hydrophobic treatment.

도로터널 화재발생시 연기유동에 관한 축소모형실험 연구

김정엽,신현준,강세구,안경철,Kim, Jung-Yup,Shin, Hyun-Joon,Kang, Se-Gu,Ahn, Kyung-Chul 한국터널지하공간학회 2004 터널기술 Vol.6 No.2

도로터널내 화재가 발생한 경우 자연환기와 종류식 환기시스템에서의 연기유동에 대한 연구가 수행되었다. Froude Scaling에 기초한 1/18 축적의 축소모형실험장치가 제작되었으며, 화원으로는 연료심지를 이용한 14.55kW 규모의 연소기가 사용되었다. 화원으로부터 등비간격으로 터널천정부근과 수직방향의 온도분포가 측정되었으며, 연소가스의 농도가 피난대피구 입구에서 측정되었다. 연구결과로서 자연환기시스템에서 비상대피구가 225m 간격으로 설치되어 있을 경우 비상대피구 구간의 연기확산시간은 256초가 되며, 20MW의 화재강도에 대해 화염역류를 완전히 방지하기 위해서는 터널풍속을 2.8m/s로 형성해 주어야 한다. In this study, smoke movement in tunnel fire with natural and longitudinal ventilation systems has been investigated. Reduced-scale experiments were carried out under the Froude scaling using 14.55kW fire source with a wick and experimental data is obtained with 1/18 model tunnel test. Temperature profiles were measured under the ceiling and vertical direction along the center of the tunnel and poisonous gas was measured at emergency exit point. The results show that refuge time for 225m intervals of emergency exit in case of natural ventilation systems is 256 seconds and critical velocity for sufficient back-layer prevention is 2.8m/s for fire strength of 20MW.

터널에서 차량의 운행에 의해 생성되는 비정상 유동에 대한 실험적 연구

김정엽,신현준,Kim, Jung-Yup,Shin, Hyun-Joon 한국터널지하공간학회 2009 한국터널지하공간학회논문집 Vol.11 No.4

도로터널내 열유동장의 형성은 여러 가지 요인의 영향을 받는다. 즉 차량의 이동에 의한 피스톤 효과, 환기설비의 환기력, 자연풍 영향, 화재시 부력 등에 따라 도로터널내 기류가 형성된다. 차량의 이동에 의한 피스톤 효과는 도로터널내 기류생성의 일차적인 요인이며, 화재시 연기의 초기 거동에 영향을 줄 수 있다. 본 연구에서는 도로터널내 차량의 이동에 의해 생성되는 비정상 기류를 분석하기 위해서 단순한 형태의 터널과 차량에 대한 축소모형실험장치를 제작하고 실험을 수행하였다. 기본형, 전두부 사변형, 후두부 계단형의 3가지 형태로 차량의 형상을 변화시켜가며 차량운행에 따라 형성되는 터널내 압력과 기류속도를 측정하였다. 실험결과 터털내 생성되는 압력과 속도의 크기는 "기본형>후두부 계단형>전두부 사변형"의 순서로 증가하였다. 실험결과는 향후 3차원 수치해석 결과와의 비교, 검토를 통해서 수치해석 기술의 보완 및 신뢰성 확보를 위한 기초자료로 활용될 수 있다. The thermo-flow field in road tunnel is influenced by some facts such as piston effect of vehicle's move, operation of ventilation facilities, natural wind and buoyancy effect of fire plume. Among those, piston effect is one of primary causes for formation of air flow in road tunnel and has an effect on initial direction of smoke flow in tunnel fire. In this study to analyze the unsteady flow in the tunnel caused by the run of vehicle, the experimental study of vehicle-induced unsteady flow on a reduced-scale model tunnel is presented. While the three types of vehicle shape such as basic type of rectangular shape, diamond-head type and stair-tail type are changed, the pressure and air velocity variations with time are measured. The rising ratio of pressure and velocity are in order of "basic type of rectangular shape > stair-tail type > diamond-head type". The experimental results would be good data for development of a numerical method on the vehicle-induced unsteady tunnel flow.

PMMA 나노 기둥의 압축시험에 대한 분자동역학 해석

김정엽(Jung Yup Kim),김재현(Jae-Hyun Kim),최병익(Byung Ik Choi) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5

PMMA has been extensively adopted in Nano Imprint Lithography(NIL). PMMA nano-structures experience severe mechanical load and deformation during NIL process, and understanding its mechanical behavior is very important in designing and optimizing NIL process. One of the most promising techniques for characterizing the mechanical behavior of nano structures is nano pillar compression test. In this study, the mechanical behaviors of PMMA pillars during compression test are analyzed using Molecular Dynamics. Two methods for simulation of PMMA nano pillars are proposed. The stress-strain relationship of nano-scale PMMA structure is obtained based on CVFF(Covalent Valence Force Fields) potential and the dependency of the applied strain rate on the stress-strain relationship is analyzed. The obtained stress-strain relationships can be useful in simulating nano-scale PMMA structures using Finite Element Method(FEM) and understanding the experimental results obtained by compression test of PMMA nano pillars.

건축물 제배연시나리오 작성을 위한 구획실 발열특성 연구

김정엽(Jung-Yup Kim),신현준(Hyun-Joon Shin) 대한설비공학회 2009 대한설비공학회 학술발표대회논문집 Vol.2009 No.-

The theoretical bases on characteristics of heat release rate in compartment of building for scenario of smoke management are introduced and the numerical applications to simple compartment model are carried out. The growth stage which is important for smoke management design is modelled as t-squared fire curve including fire growth coefficient with related to growth rate. The conditions for the happening of flashover is presented such as 600℃ of temperature or 20㎾/㎡ of radiation heat flux. After the flashover happen, the fire in compartment changes to fully developed fire having the charateristics of ventilation-controlled fire. As the result of numerical analysis to simple compartment model, the time to reach 900K under ceiling for condition of medium growth is twice for condtion of fast growth.

Chilled Beam 공조시스템의 유인성능 해석

김정엽(Jung-Yup Kim),신현준(Hyun-Jun Shin),김지석(Ji-Seok Kim),주상현(Sang-Hyun Joo) 대한설비공학회 2013 설비공학 논문집 Vol.25 No.5

Since a chilled beam system can reduce the conveyance energy for air conditioning and has many advantages in terms of constructability and indoor environment, its supply has been rapidly expanding mainly in Europe. For this chilled beam system to be effectively available in Korea, a product suitable for the domestic climatic environment and HVAC system operating conditions needs to be developed. Also, domestic products need to have an edge in cost competitiveness compared to overseas products. In this study, the induction structure of a chilled beam is deduced and an analysis on the induction performance is carried out while the chilled beam system that meets domestic situations is in the process of development.

유압식 이족 휴머노이드 로봇의 ZMP 기반 게인 스위칭 알고리즘을 이용한 관절 위치 제어

김정엽(Jung-Yup Kim),Jessica K. Hodgins 제어로봇시스템학회 2009 제어·로봇·시스템학회 논문지 Vol.15 No.10

This paper proposes a gain switching algorithm for joint position control of a hydraulic humanoid robot. Accurate position control of the lower body is one of the basic requirements for robust balance and walking control. Joint position control is more difficult for hydraulic robots than it is for electric robots because of an absence of reduction gear and better back-drivability of hydraulic joints. Backdrivability causes external forces and torques to have a large effect on the position of the joints. External ground reaction forces therefore prevent a simple proportional-derivative (PD) controller from realizing accurate and fast joint position control. We propose a state feedback controller for joint position control of the lower body, define three modes of state feedback gains, and switch the gains according to the Zero Moment Point (ZMP) and linear interpolation. Dynamic equations of hydraulic actuators were experimentally derived and applied to a robot simulator. Finally, the performance of the algorithm is evaluated with dynamic simulations.

기계식 균형 장치가 적용된 전동 휠체어의 개발

김정엽(Jung-Yup Kim) 한국생산제조학회 2013 한국생산제조시스템학회 학술발표대회 논문집 Vol.2013 No.4

건축물 계단에서의 연돌효과 저감방안에 대한 현장실험 연구

김정엽(Jung-Yup Kim),김지석(Ji-Seok Kim),이수각(Su-Gak Lee) 대한설비공학회 2015 설비공학 논문집 Vol.27 No.9

The winter stack effect that occurs in vertical construction passages such as the stairwell or elevator shaft of a high-rise building negatively affects living environments, energy usage, and personal safety; therefore, a mitigation of the stack effect is required to improve building conditions. Recently, circulation-type facilities that comprise the usage of air blowers and vertical ducts were proposed as part of a mechanical approach to quantitatively control the stack effect. In this study, these circulation-type facilities were installed in a building stairwell and the performance of the device was evaluated during its operation. A numerical-analysis result was obtained under the test conditions using a network-model-based, numerical-analysis method, and the result was then used for a comparison with the test result.

실규모 연기제어 실험연구를 위한 Pre-Pilot Test Bed 구축

김정엽(Kim, Jung-Yup),신현준(Shin, Hyun-Joon),주상현(Joo, Sang-Hyun) 한국화재소방학회 2012 한국화재소방학회 학술대회 논문집 Vol.2012 No.춘계

건축물에서 화재가 발생할 경우 연기에 의한 요인이 인명피해의 주요 원인으로 파악되고 있다. 특히 건축물이 고층화, 복합화, 대형화되면서 화재시 연기에 취약한 건축물이 증가하고 있고, 또한 기존의 연기제어 설계기준이 개선되어야 할 필요가 발생하고 있다. 이러한 요구에 부응하기 위해서는 새로운 조건에 대한 연기확산 및 연기제어에 대한 수행되어야 하며, 이론 수치해석적 연구와 더불어 실제적인 실험적 연구가 되어야 한다. 한국건설기술연구원 화재안전연구센터에는 5층규모의 제배연 실험동이 건립되어 있으며, 다양한 건축물 조건 및 연기제어 방식에 따른 실규모의 실험적 연구가 가능하도록 설비가 구성되어 있다. 본 논문에서는 이러한 Pre-Pilot Test Bed의 구축현황과 관련 실험내용을 소개하고자 한다.