• Smart Structures and Systems
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• v.24 no.6
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• pp.803-812
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• 2019

Triplex composite is an epoxy-bonded joint structure, which constitutes the secondary barrier in a liquefied natural gas (LNG) carrier. Defects in the triplex composite weaken its shear strength and may cause leakage of the LNG, thus compromising the structural integrity of the LNG carrier. This paper proposes an autonomous triplex composite inspection (ATCI) system for visualizing and classifying hidden defects in the triplex composite installed inside an LNG carrier. First, heat energy is generated on the surface of the triplex composite using halogen lamps, and the corresponding heat response is measured by an infrared (IR) camera. Next, the region of interest (ROI) is traced and noise components are removed to minimize false indications of defects. After a defect is identified, it is classified as internal void or uncured adhesive and its size and shape are quantified and visualized, respectively. The proposed ATCI system allows the fully automated and contactless detection, classification, and quantification of hidden defects inside the triplex composite. The effectiveness of the proposed ATCI system is validated using the data obtained from actual triplex composite installed in an LNG carrier membrane system.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.2
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• pp.146-153
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• 2013

CNG buses has contributed to improve air quality in cities. But it is difficult to meet the next emission regulations such as EURO-VI without the help of additional post-processing device. Hydorgen has higher flame speed and lower combustion temperature that make it thermal efficiency increase with leaner operation. Using hydrogen natural gas blend (HCNG) fuel is promising technology which can reduce $NO_x$ and $CO_2$ emissions for a natural gas vehicle. However, fuel flow rate of HCNG should be increased since hydrogen's energy density per volume is much smaller than natural gas. In the present study, the characteristics of fuel supply system and its applicability were evaluated in a heavy duty natural gas engine. The results showed that the potential of fuel pressure regulator and fuel metering valve had enough capacity with HCNG. Employed mixer did not affect the distribution characteristics of mixture.

• Journal of the Korean Institute of Gas
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• v.14 no.1
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• pp.42-46
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• 2010

BOG(Boil Off Gas) is formed about 0.05 vol%/day from LNG(Liquefied Natural Gas) tanks of LNG receiving terminal. To recycle the BOG using direct contacting, Previously the quantities of LNG and BOG is mixed at the ratio of 11:1 by mass. However simple this process uses, there is the difficulty of processing operation resulted from decrease of using LNG in summer. To complement these shortcomings, Advantages of the process are investigated by comparison of cost and analysis of the indirect contact method using LNG cold energy. It was studied that principles and types of development using LNG cold energy which is abandoned in the carburettor and found how to contact each to find the appropriate cold energy development process. Therefore, in this research, the indirect contact method will be investigated the feasibility of a comparative analysis by using HYSYS.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05b
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• pp.1-6
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• 2002

Plasma processing of semiconductor materials plays a dominant role in microelectronic technology. During last century, plasma have gone a way from laboratory phenomena to industrial applications due to intensive progress in both scientific and industrial trends. Improvement and development of new experience together with development of plasma theory and plasma diagnostics methods. A most parameters (pressure, flow rate, power density) and various levels of plasma system (energy distribution, volume gas chemistry, transport, heterogeneous effects) to understand the whole process mechanism. It will allow us to choose a correct ways for processes optimization.

• Journal of the Korean Society of Visualization
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• v.2 no.1
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• pp.25-31
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• 2004

Droplet size is one of the most important parameter which controls the performance of the combustion system using liquid fuel or oxidizer. Droplet formation and its size are mainly affected by the injection velocity and ambient gas density. Recently, droplet size measurement was conducted by PDPA or Malvern particle analyzer using laser light. But at this paper image processing method was developed to measure droplet size. And its validation was investigated with reticle.

• Journal of the Semiconductor & Display Technology
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• v.1 no.1
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• pp.9-13
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• 2002

A polyimide-type electrostatic chuck (ESC) was fabricated for the application of holding 8-inch silicon wafers in the oxide etching equipment. For the fabrication of the unipolar ESC, core technologies such as coating of polyimide films and anodizing treatment of aluminum surface were developed. The polyimide films were prepared on top of thin coated copper substrates for the good electrical contacts, and the helium gas cooling technique was used for the temperature uniformity of the silicon wafers. The ESC was essentially working with an unipolar operation, which was easier to fabricate and operate compared to a bipolar operation. The chucking force of the ESC has been measured to be about 580 gf when the applied voltage was 1.5 kV, which was considered to be enough force to hold wafers during the dry etching processing. The employment of the ESC in etcher system could make 8% enhancement of the wafer processing yield.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.919-920
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• 2009

액화 천연 가스 플랜트 시뮬레이터는 막대한 자본 투자가 필요한 대형 시스템 설계 및 건설 단계에서 사전에 설계 오류 검출 및 시스템 검증을 함으로써 많은 비용을 절약해줄 수 있는 중요한 시스템이다. 이 연구에서는 플랜트, 시뮬레이터, 운전원 훈련 시스템 및 제어시스템을 운전하는 과정에서 발생하는 정보를 효과적으로 처리하기 위해서 구축되는 정보 처리 시스템의 기본 설계에 관한 내용을 소개한다. 전체 시스템은 물리적 플랜트와 가상 플랜트로 나눌 수 있고 가상 플랜트는 시뮬레이터와 운전원 훈련 시스템으로 구현되며, 제어 시스템은 PLC로 구현하고 Modubus 프로토콜과 OPC 서버를 통해 데이터 처리가 가능하다. 플랜트로부터 생성되는 데이터 처리에서는 실시간 데이터 처리 속도가 중요하므로 실시간 데이터베이스를 도입하였다. 실제 플랜트 데이터와 시뮬레이터 데이터는 상호 교환이 가능하도록 구성하였다. 본 시스템 설계는 기본 설계 단계이므로 향후 LNG 플랜트에 적용하기 위해서는 상세 설계가 필요하다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.440-447
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• 2002

This paper considerated about exact flow volume calculation method from factors having an influence on measurement and introduced in anesthesia ventilator realized spirometry system. System used differential pressure sensing method with factors, that is temperature, pressure, gas density, humidity and mucus etc. System optimized for low power system for mobile system. System composed analog interface part, signal processing part, display part. Analog interface part have differential pressure flow sensor and defferential pressure sensor. Signal processing part have AVR processor for low power system display part use serial port (RS232, SPT). so it display at pc monitor or send to anesthesia ventilator. System is stable by linearizing 2th characteristics of flow-differential pressure, auto correction of sensor. Noise reduced by algorithm with analog filter and digital processing. Small, light, low power system is good at mobile system and applied to patient in emergency or mobile. and, System is useful at anesthesia ventilator by using flow sensor.

• Journal of Biosystems Engineering
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• v.38 no.4
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• pp.306-311
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• 2013

Purpose: With the ever-rising energy prices, thermal energy heavily consuming facilities of the agricultural sector such as commercialized greenhouses and large-scale Rice Processing Complexes (RPCs) need to cut down their energy cost if they must run profitable businesses continually. One possible way to reduce their energy cost is to utilize combustible agricultural by-products or low-price oil instead of light oil as the fuel for their boiler systems. This study aims to analyze the heavy oil combustion characteristics of a newly developed hot water boiler system that can use both rice husk and heavy oil as its fuel convertibly. Methods: Heavy oil combustion experiments were conducted in this study employing four fuel feed rates (7.6, 8.5, 9.5, 11.4 $l/h$) at a combustion furnace vacuum pressure of 500 Pa and with four combustion furnace vacuum pressures (375, 500, 625, 750 Pa) at fuel feed rates of 9.5 and 11.4 $l/h$. Temperatures at five locations inside the combustion furnace and 20 additional locations throughout the whole hot water boiler system were measured to ascertain the combustion characteristics of the heavy oil. From the temperature measurement data, the thermal efficiency of the system was calculated. Flue gas smoke density and concentrations of air-polluting components in the flue gas were also measured by a gas analyzer. Results: As the fuel feed rate or combustion furnace vacuum pressure increased, the average temperature in the combustion furnace decreased but the thermal efficiency of the system showed no distinctive change. On the other hand, the thermal efficiency of the system was inversely proportionally to the vacuum level in the furnace. For all experimental conditions, the thermal efficiency remained in the range of 80.1-89.6%. The CO concentration in the flue gas was negligibly low. The NO and $SO_2$ concentration as well as the smoke density met the legal requirements. Conclusions: Considering the combustion temperature characteristics, thermal efficiency, and flue gas composition, the optimal combustion condition of the system seemed to be either the fuel feed rate of 9.5 $l/h$ with a combustion furnace vacuum pressure of 375 Pa or a fuel feed rate of 11.4 $l/h$ with a furnace vacuum pressure between 500 Pa and 625 Pa.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.156.1-156.1
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• 2011

It is of great importance to predict operating parameter characteristics of an integrated fuel processor by the increased life-time and system performance. In this study, computational analysis is performed to gain fundamental insights on transport phenomena and chemical reactions in reformer which consists of preheating, steam reforming, and water gas shift reaction beds. Also, a top-fired burner locates inside of the reforming system. The combustor is providing thermal energy necessary for the steam reforming bed which is a endothermic catalytic reactor. Two-dimensional numerical model of the integrated fuel processing system is introduced for the analysis of heat and mass transport phenomena as well as surface kinetics and catalytic process. A kinetic model was developed and then computational results were compared with the experimental data available in the literature. Subsequently, parameter study using the validated steam methane reforming model was conducted by considering operating parameters, i.e. steam to carbon ratio and temperature.