• 대한의용생체공학회:의공학회지
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• 제25권3호
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• pp.207-215
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• 2004

본 연구에서는 유전 프로그램을 이용하여 6가지 형태의 금속 와이어 배치를 가진 전극을 생성하여 각 전극이 3차원 형태의 달팽이관에 미치는 기계적인 영향과 그 거동을 유한요소법을 이용하여 분석하였다. 그리고 전극이 삽입되는 달팽이관은 helico-spiral 근사방법에 의해 결정된 식을 이용하였으며, 고실계단(scala tympani)의 형태는 실제 고실계단 단면의 영상정보를 추출하여 얻어내었다. 해석결과 금속 와이어가 평행하게 배치될 경우 가장 큰 힘을 달팽이관 외벽에 전달하며, 삽입에도 가장 큰 힘이 필요한 것을 알 수 있었다. 그리고 달팽이관은 3차원 구조이므로 전극이 삽입되면서 삽입 전에 자극 사이트가 바라보도록 설정한 방향보다 조금 돌아감을 확인하였다. 이 연구의 결과로부터 전극의 강성이 외상(trauma)을 줄이는데 중요하다는 것을 알 수 있다.

• 한국정밀공학회지
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• 제31권10호
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• pp.857-863
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• 2014

In this work, we introduce various bonding technologies for 3D package and suggest Insert-Bump bonding (ISB) process newly to stack multi-layer chips successively. Microstructure of Insert-Bump bonding (ISB) specimens is investigated with respect to bonding parameters. Through experiments, we study on find optimal bonding conditions such as bonding temperature and bonding pressure and also evaluate in the case of fluxing and no-fluxing condition. Although no-fluxing bonding process is applied to ISB bonding process, good bonding interface at $270^{\circ}C$ is formed due to the effect of oxide layer breakage.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2005년도 제31회 KOSCO SYMPOSIUM 논문집
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• pp.238-244
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• 2005

This study performs the pilot-plant experiments to evaluate the effect of the oxygen enrichment on the co-incineration of municipal solid waste and organic sludge from a wastewater treatment facility. The design capacity of the stoker-type incinerator pilot-plant is 150 kg/h. Combustion chamber temperatures were measured as well as the stack gas concentrations, i.e., NOx, CO, and the residual oxygen. The maximum ratio of organic sludge waste to the total waste input is 30%. Also the oxygen-enriched air with 23% of oxygen in supplied air is used for stable combustion. As the co-incineration ratio of the sludge increased up to 30% of the total waste input, the primary and the secondary combustion chamber temperature was decreased $to900^{\circ}C$ (primary combustion chamber), $750^{\circ}C$(secondary combustion chamber), respectively, approximately $200^{\circ}C$ below the incineration temperature of the domestic waste only (primary: $1,100^{\circ}C$, secondary: $950^{\circ}C$). However, if the supplied air was enriched to 22% oxygen content in air, the incinerator temperature was high enough to burn the waste mixture with 30% sludge, which has the heating value of 1,600 kcal/kg.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2004년도 제28회 KOSCO SYMPOSIUM 논문집
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• pp.149-157
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• 2004

In the present paper we studied experimentally fundamental optimization of oxygen enriched pyrolysis melting incinerator, Characteristics of this system was confirmed dealing with the gas flow and combustion properties for the inside secondary air injection. The experiment setup has a disposal rate of 30kg/hr which was measured by the inside temperature and gas. Along with above experiments, the three-dimensional computation was employed to analyse the combustion fluid dynamics and gas residence time. Equations for turbulence and heat - transmission as well as chemical reactions were solved by using common codes. The experimental combustion chamber was composed of staged combustion types structure for reducing NOx. Finally, it was verified that the control of the secondary air and air ratio of thermo stack were important. In the computational analysis, it showed reasonable agreement with the experimental results regarding the temperature and discharged gas concentration.

• 한국응용과학기술학회지
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• 제28권4호
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• pp.455-463
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• 2011

The average sulfur content of crude oil is 2.2%. Coal is about 0.3 to 4.0 percent of the sulfur gases or particles being discharged into the atmosphere through the chimney as 1 to 2% $SO_3$(Sulfur trioxide) and about 95% of the $SO_2$ is reported. $SO_3$ gas, which has many different causes of, as the combustion of sulfur containing fuel during the air due to the excess $SO_2$ gas is oxidized to $SO_3$ gas. Sulfur trioxide emitted from high sulfur heavy oil fired boiler caused white plume in stack and high temperature and cold end corrosion of facilities. So, in order to control sulfur trioxide concentration of Fuel gas in boiler, various of additives are used in other foreign. They are injected to Fuel Oil and consumed in boiler and reduce ash and the conversion rate of sulfur trioxide. In domestic, MgO compounds are used as additives but the total volume of them are made from other foreign company. In this study, MgO compounds were developed with liquid MgO compounds and field application was accomplished. The effect of newly developed chemicals and process were nearly equal to foreign products. In Consequent, the chemicals and process produced by newly developed technology can be substituted for foreign products and reduce the cost of plant operation.

• 전자공학회논문지A
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• 제30A권10호
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• pp.33-40
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• 1993

A reflection type 16x8 S-SEED array from LP(Low Pressure)-MODVD-grown GaAs/AlGaAs extremely shallow quantum well(ESQW) structures, with 4% Al fraction, has been fabricated. Its intrinsic region consists of 50 pairs of alternating 100.angs. GaAs and 100.angs. $Al_{0.04}$Ga$_{0.96}$As layers. A multilayer reflector stack of $Al_{0.04}$/Ga$_{0.96}$ As(599$\AA$)/AlAs(723$\AA$) was incorporated for the reflection plane below the p-i-n structures. The device processing after the MOCVD growth includes the mesa etching, isolation etching, insulator deposition, p & n metallization, and AR(Anti-Reflection) coating. For switching characteristics of the S-SEED in the form of p-i-n ESQW diode, the maximum optical negative resistance was observed at 856nm. Reflectance measurements showed a change from 15.6% to 43.3% for +0.9V to -6V bias. The maximum contrast ration of the S-SEED array was 2.0 and all the 128 devices showed optical bistability with contrast ratios over 2.4 at 5V reverse bias.

• 전자공학회논문지SC
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• 제46권1호
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• pp.63-67
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• 2009

전하 펌프의 전류 부정합은 위상 고정 루프의 주파수 성분에 기준 스퍼를 발생시킴으로써 특성을 떨어뜨리게 한다. 전류 부정합은 캐스코드 출력단과 같이 전하 펌프의 출력 저항을 높여줌으로써 감소시킬 수 있다. 그러나 공급 전압이 낮아짐에 따라 트랜지스터를 쌓기 힘들어지게 된다. 본 논문에서는 전류 부정합을 줄이기 위한 새로운 방법을 제안하였다. 제안한 방법은 출력 단의 채널 길이 변조에 의한 전류 변화를 피드포워드 방식으로 보상해 주는 것이다. 새로운 방법에 대한 시뮬레이션은 CMOS $0.18{\mu}m$ 공정을 이용하였다.

• 한국수소및신에너지학회논문집
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• 제18권3호
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• pp.292-300
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• 2007

A dynamic system model of a proton exchange membrane fuel cell(PEMFC) has been developed. The PEMFC of this study has large active area with water cooling in order to simulate the performance of the commercially viable PEMFC system for the transportation. A PEMFC stack model is a transient thermal model which is respond to the dynamic change of the coolant temperature and the flow rate. The dynamic cooling system model has been developed to determine the coolant flow rate and the coolant temperature. Prior to the system level study, thermal management criteria have been set up and brought to the control command of the cooling system. Since the system model is designed to evaluate the effect of thermal management on the system performance, it is attempted to determine the proper control algorithm of the cooling system so that the PEMFC system is working on the thermal management criteria. As a result of simulation, feedback controlled cooling system consumes less power and produce more power comparing with that of conventionally controlled cooling system.

• 건설안전기술
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• 통권41호
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• pp.88-101
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• 2007

Recently, the condensation of walls often occurring in domestic high-rise apartment buildings is an important problem. The main purpose of this study is to develop the prediction method for the surface condensation on curtain wall in high-rise apartment buildings. Therefore, in this study, we first analyzed exterior climate factors through the analysis of the Seoul climate data and predicted the change of indoor temperature by using Apache program to find the cause of the condensation state and to prevent condensation. Also, according to this result, exterior climate factors and interior factors, which caused the condensation, was examined. The thermal performance of the curtain wall and the range of potential condensation were analyzed to focus on high-rise apartment buildings through computer simulation programs. The results are as $follows;^1$) The frame edge of curtain wall has a higher U-value than in the center by $30%^2$) Because of stack effect, the rooms on the higher floor have a lower external ventilation rate resulting to a higher relative humidity3) Installing a ventilation system($20m^3$/h. person) makes it possible to have a higher external ventilation rate, resulting to a lower relative humidity.

• 한국소음진동공학회논문집
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• 제14권11호
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• pp.1176-1181
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• 2004

In high-capacity disk drives with ever-growing track density, the allowable level of position error signal(PES) is becoming smaller and smaller. In order to achieve the high TPI(track per inch) disk drive, it is necessary to improve the writing accuracy during the servo track writing(STW) Process through the reduction of track mis-registration sources. Among the main contributors of the non-repeatable runout(NRRO) PES, the disk vibration and the head-stack assembly vibration is considered to be one of the most significant factors. Also the most contributors of repeatable runout(RRO) come from the contributors of NRRO which is written-in at the time of STW process. In this paper, the effect of NRRO on servo written-in RRO is Investigated by experimentally, and the experimental result shows that the written-in RRO can be effectively reduced through a STW process under low dense medium condition such as semi-vacuum.