• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.434-435
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• 2005

In this work, the ITO thin films were prepared by FTS (Facing Targets Sputtering) system under different sputtering conditions which were varying $O_2$ gas flow, input current and working gas pressure. As a function of sputtering conditions, electrical and optical properties of prepared ITO thin films were measured. The electrical characteristics, surface roughness and transmittance of the ITO thin films were evaluated by Hall Effect Measurement, AFM, and UV-VIS spectrometer respectively. In addition, I-V properties of OLED cells were measured by 4156A(HP).

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.11 no.3
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• pp.219-228
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• 2001

Objective : For the purpose of preparing the fundamental data and health promotion and control program on organic solvents in air of manufacturing industry. Methods : The author surveyed number of organic solvent components which was used in working site and also determined the organic solvents concentration in air of 927 manufacturing industries and 1,267 working process with gas chromatography(NIOSH manual) for five years from 1995 to 1999. Results : Mean number of solvents components by type of industry, working process was number of 12. There were exceeded to TLV of 1,2-dichloroethane in textile manufacturing industry N,N-dimethyl furan in tanning and dressing of leather ; luggage, handbags, saddlery, harness and footwear manufacturing industry and chemical and chemical product manufacturing industry by type of industry. There were exceeded to TLV of 1,2-dichloroethane in handwriting and drawing process, cellosolve in adhesive spreading process, N,N-dimethly furan in production of solvent process and adhesion process by working process Total exceeded rate to threshold limit values of organic solvents mixture were 12.9% for EI(Exposure index) and 10.0% for Em(Estimation of mixture) by type of industry, 11.3% for EI and 8.2% for Em by type of working process. The highest exceed rate was 36.7% for EI in tanning and dressing of leather ; luggage handbags, saddlery, harness and footwear manufacturing industry and 29.0% for Em in textile manufacturing industry. The highest exceeded rate was 23.1% for EI and 12.5% for Em in adhesive spreading process by working process. Mean values of total subjects by type of industry and type of working process were $0.7{\pm}1.8$ for EI and $0.7{\pm}1.7$ for Em respectively. Conclusions : As above results, the author suggest that it makes the environmental control program on 1.2-dichloroethane, N,N-dimethyl furan, cellosolve by kind of organic solvent and on textile manufacturing industry, tanning and dressing of leather ; luggage, handbags, saddlery harness and footwear manufacturing industry by type of industry, and on handwriting, drawing process and adhesive spreading process and adhesion process by type of working process.

• Transactions of the Korean Society of Mechanical Engineers
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• v.5 no.2
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• pp.151-157
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• 1981

The concept of available evergy has been adopted in terms of effectiveness for and evaporator of vapor power cycle. This kind of practice is emphasezed in a case of heat and power cogeneration in order to find optimum condition for the energy utilzation of the exhaust gas. It has beed shown that the optimum condition can be given in terms of the saturation pressure or the saturation temperature of the working fluid. Similar method has been applide to show that the effectiveness is increased asymptotically with the number of evaporator stanges.

• Proceedings of the Korean Geotechical Society Conference
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• 1993.10b
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• pp.133-162
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• 1993

The environment of underground spaces might be considered in view of working environment during the construction and living environment after completion of the construction work. For controlling environment of underground space, an appropriate measures have to be taken on the governing factors such as air flow, dust, gases, heat, radiation, noise, illumination and water. The more critical matter, in underground environmental point of view, is underground disasters such as fire, gas explosion and water inrush. This paper presents the general introduction of these factors mentioned above and some outcomes of research works as of now.

• Proceedings of the KAIS Fall Conference
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• 2001.05a
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• pp.79-81
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• 2001

저압 기상 영역에서 Anhydrous HF 가스와 Methanol vapor를 사용하는 산화막 식각공정을 수행하기 위하여 (1) 반응기 부피의 최소화, (B) 공정압력의 최소화, (3) 고순도 알루미나 Reactor 적용, (4) Cluster화의 개념을 적용한 VPC 장치를 제작하였다. Wafer의 온도, HF의 분압 및 Working Pressure 등의 공정변수에 따른 Oxide Wafer의 식각특성의 변화를 확인하였다. 또한 Etch Uniformity를 향상시키기 위하여 Shower Head 구조를 변경시켜서 실험하였으며, CFD Simulation을 이용하여 Reactor내에서의 HF gas 및 Methanol vapor의 분율을 예측하였다.

• IE interfaces
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• v.6 no.2
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• pp.171-181
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• 1993

In this study, a process management system is designed that can automatically control the heat treating atmosphere, and a managment software is developed to monitor and control continously the heat treating process using a n interface device. Especially, a communication protocol is developed to control and monitor atmosphere condition, temperature, surrounding gas, and time. The developed interface device, called COMPORT SELECTOR is to send and receive information from PID controllers and PLC via RS-232C communication. This system will reduce manufacturing cost and cycle time, and improve the effectiveness of working process and quality.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.303-306
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• 2009

High temperature solid oxide fuel cells (SOFCs) offer a clean, pollution-free technology to electrochemically generate electricity at high efficiencies. Solid oxide fuel cells in several different designs have been investigated; these include planar and tubular geometries. The tubular type cell is widely researched due to it have advantages about thermal expansion and sealing issues. Unfortunately, lab scale tubular cell for testing has thermal expansion and sealing problems. The previous Jig for lab scale tubular cell testing has many sealing problems. When we feed fuel gas to jig inlet, ceramic glue sealant has amount of gas expansion pressure, because temperature of feeding gas changes ambient temperature to high temperature ($700{\sim}900^{\circ}C$). Furthermore, when we carry out long time test, something like degradation test, crack of ceramic glue sealant due to weakness of mechanical properties can make stop working the test. Additionally, we reduce setting process for assembling, because micanite is not required drying or debinding process.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.6
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• pp.769-777
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• 1999

This paper presents models for the dynamic simulation of a regenerative gas turbine and describes dynamic behaviors of a small regenerative engine. A quasi-steady model is introduced where the inertia of the working fluid is assumed to be negligible compared with the mechanical inertia of the rotating shaft. Based on this quasi-steady model, the transient model for the heat exchanger is employed to simulate the unsteady heat exchange in the recuperator. The effect of the thermal inertia of the recuperator metal on transient behaviors is analyzed by comparing the predicted results of the transient and steady state heat exchanger models. For several load change modes such as sudden increase, decrease and periodic variation, engine dynamic characteristics are investigated by applying a fuel control logic for the constant shaft speed. It is found that the thermal inertia of the recuperator metal has a dominant effect on the whole engine dynamic behavior.

• Journal of Welding and Joining
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• v.8 no.3
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• pp.60-69
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• 1990

Plasma arc cutting is a fusion cutting process in which a gas-constricted arc is employed to produce a high-temperature, high-velocity plasma jet on the workpiece. This process provides some advantages such as increased cutting velocity, excellent working accuracy and the ability to cut special materials (widely used stainless steels and Al-alloys, for example), when compared with iconventional oxyfuel gas cutting. From the view point of price and reliability of the power source, plasma arc cutting has also some distinct advantages over laser beam cutting. High-speed machines with NC or CNC systems are needed for the plasma arc or laser beam cutting process, while for oxyfuel gas cutting, low-speed machines with copying templates or optical-shape tracking sensors can be applied. The low price and high flexibility of the microprocessor arc contributing more and more the application of CNC system in the plasma arc cutting process, as in other manufacturing fields. From these points of view, a microprocessor-based plasma arc cutting system was developed by using a reference-pulse system, and its performance was tested. The interpolating routines were programmed in the assembly language for saving the memory volume and improving the compouting speed, which has an intimate relationship with the available cutting velocity.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1236-1238
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• 1994

TiAlN thin films were prepared by a multi target r.f magnetron sputtering system under different conditions. We have investigated the resistivity and T.C.R. (Temperature Coefficient of Resistance) characteristics of TiAlN films deposited on $Al_2O_3$ and glass substrates by sputtering in an $Ar:N_2$ gas mixture. We used Al and Ti metal as Target Material and $Ar:N_2$ gas as working gas. We varied the partial pressure ratio of $N_2/Ar$ from 0.2/7 to 1.0/6.2 (SCCM). And the R.F power of Ti and Al Target also were varied as 160/240, 200/200 and 240/160(W). In this experiment, we can get the precision thin film resistor with a very low T.C.R. (Temperature Coefficient of Resistance) below 25 ppm ${\Omega}/^{\circ}C$.