• 한국전기전자재료학회논문지
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• 제13권10호
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• pp.812-816
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• 2000

It is very important to understand the correlation of between inter dielectric(ILD) CMP process and various facility factors supplied to equipment to equipment system. In this paper, the correlation between the various facility factors supplied to CMP equipment system and ILD-CMP process was studied. To prevent the partial over-polishing(edge hot-spot) generated in the wafer edge area during polishing, we analyze various facilities supplied at supply system. With facility shortage of D.I water(DIW) pressure, we introduced an adding purified $N_2$(P$N_2$)gas in polishing head cleaning station for increasing a cleaning effect. DIW pressure and P$N_2$gas factors were not related with removal rate, but edge hot-spot of patterned wafer had a serious relation. We estimated two factors (DIW pressure and P$N_2$gas) for the improvement of CMP process. Especially, we obtained a uniform planarity in patterned wafer and prohibited more than 90% wafer edge over-polishing. In this study, we acknowledged that facility factors supplied to equipment system played an important role in ILD-CMP process.

• 유기물자원화
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• 제25권3호
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• pp.79-89
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• 2017

경기도 포천시 관내 하수 및 인분 처리장들에서 발생하는 유기성 슬러지를 지렁이 먹이로 공급하였을 때, 지렁이 사육상의 수용성 양이온, 음이온 농도 및 pH, 전기전도도 등의 이화학 성상 변화를 추적하였다. 먹이로 공급된 슬러지의 pH, 전기전도도, 유기물 함량 및 함수율은 지렁이의 단기적 섭식이 가능한 범위였으나, 슬러지의 공급량이 늘어감에 따라 섭식속도가 느려지고 결국 지렁이 사멸현상이 나타났다. 또한 슬러지 공급량이 늘어감에 따라 지렁이 사육상이 산성화되었고, 전기전도도가 높아지는 것으로 보아 염류집적 현상이 일어난 것을 알 수 있었으며, 동시에 사육상의 수용성 음이온 및 양이온 농도가 높아졌다. 특히 수용성 이온 중 ${NO_3}^-$의 농도 집적이 두드러졌다.

• Tribology and Lubricants
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• 제38권2호
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• pp.33-40
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• 2022

In this study, we present rotor dynamic analysis and operation test of a turbo expander for a hydrogen liquefaction plant. The turbo expander consists of a turbine and compressor wheel connected to a shaft supported by two hydrostatic radial and thrust bearings. In rotor dynamic analysis, the shaft is modeled as a rigid body, and the equations of motion for the shaft are solved using the unsteady Reynolds equation. Additionally, the operating test of the turbo expander has been performed in the test rig. Pressurized helium is supplied to the bearings at 8.5 bar. Furthermore, we monitor the shaft vibration and flow rate of the helium supplied to the bearings. The rotor dynamic analysis result shows that there are two critical speeds related with the rigid body mode under 40,000 rpm. At the first critical speed of 36,000 rpm, the vibration at the compressor side is maximum, whereas that of the turbine is maximum at the second critical speed of 40,000 rpm. The predicted maximum shaft vibration is 3 ㎛, whereas sub-synchronous vibration is not presented. The operation test results show that there are two critical speeds under the rated speed, and the measured vibration value agrees well with predicted value. The measured flow rate of the helium supplied to the bearing is 2.0 g/s, which also agrees well with the predicted data.

• 한국전기전자재료학회논문지
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• 제28권2호
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• pp.85-91
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• 2015

A gasoline engine automobile uses high voltage generation of the ignition coil, igniting and burning mixed fuel in the combustion chamber, which drives the engine. When the electronic control unit intermits a current supplied to the power transistor, counter electromotive force with a low voltage is generated by self induction action in the ignition primary coil and a high voltage is induced by mutual induction action with the primary ignition coil in the second ignition coil. The high voltage is supplied to the ignition plug in the combustion chamber, causing a spark, igniting the compressed mixed fuel. If a very small defect occurs inside the insulating material when a voltage is applied in said ignition coil, the performance of the insulation material will get worse and breakdown by a partial discharge of corona discharge. Thus, in this experiment, we are to contribute to improve the performance and ensure the reliability of the ignition coil by investigating partial discharge characteristics according to the change of voltage and temperature when a voltage is applied to the specimen of the epoxy molding ignition coil.

• 한국생활환경학회지
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• 제18권3호
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• pp.330-337
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• 2011

This research quantified(/m²) the supplied materials at the construction stage of apartments, the main architecture form domestically, and presented the average CO₂ emission by analyzing 50 apartment complexes. The results are as follows. CO₂ emission of each type of constructions by supplied materials is architecture (78.8%), machine (8.8%), electricity (5.3%), civil engineering (3.4%), landscaping (3.4%), and communication (1.0%). The building construction charged about 79%. Average CO₂ emission of total 50 apartment complexes according to supplied material expense appeared to be 950 kg-CO₂/m², and when core-type pillar was included CO₂ emission largely increased.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 춘계학술대회 논문집 전자세라믹스 센서 및 박막재료 반도체재료 일렉트렛트 및 응용기술
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• pp.31-34
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• 2000

It is very important to understand the correlation of between inter layer dielectric(ILD) CMP process and various facility factors supplied to equipment system. In this paper, the correlation between the various facility factors supplied to CMP equipment system and ILD CMP process were studied. To prevent the partial over-polishing(edge hot-spot) generated in the wafer edge area during polishing, we analyzed various facilities supplied at supply system. With facility shortage of D.I. water(DIW) pressure, we introduced an adding purified $N_2(PN_2)$ gas in polishing head cleaning station for increasing a cleaning effect. DIW pressure and PN2 gas factors were not related with removal rate, but edge hot-spot of patterned wafer had a serious relation. We estimated two factors (DIW pressure and PN2 gas) for the improvement of CMP process. Especially, we obtained a uniform planarity in patterned wafer and prohibited more than 90% wafer edge over-polishing. In this study, we acknowledged that facility factors supplied to equipment system played an important role in ILD-CMP process.

• 한국환경과학회지
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• 제32권11호
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• pp.821-831
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• 2023

Recently, landscaping construction has played a significant role in enhancing the quality of life for citizens by creating and maintaining outdoor spaces. However, landscaping projects vary in material procurement depending on the contracting method, and they also present various challenges in defect occurrence and defect rectification due to their specialized nature. In this study, we classified different types of projects based on material procurement ratios and conducted on-site assessments of defect status by specific processes. We also analyzed the itemization of material ratios and defect rectification costs. The results revealed it was found that projects with a higher proportion of government-provided materials had the poorest defect status in terms of planting works and also incurred the highest defect rectification costs. Moreover, conflicts concerning the responsibility for defects arose. Currently, there are no specific guidelines for setting standards for the proportion of government-provided materials in landscaping construction contracts. Furthermore, there is ambiguity in the management of defect rectification. Therefore, it is necessary to establish a systematic landscaping construction contracting framework by providing institutional guidelines tailored to local governments or the circumstances of contracting entities and to conduct thorough reviews of construction processes.

• 한국전기전자재료학회논문지
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• 제26권8호
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• pp.629-634
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• 2013

The rectified voltage supplied to LED lamp is used in load and then the surplus voltage can be produced in LED lighting. In this case, LED lighting is proposed that can recyclable the excess voltage to supply power to the controller.

• 기술사
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• 제14권2호
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• pp.5-11
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• 1981

This analysis has been conducted for 8 chemical plants built in Korea during 1975-1976 and the results have been compared with those in U.S.A. observed by Kenneth M. Guthrie. Equipment and materials supplied by domestic makers are limited in activity field and occupy only 12% of all equipment and material cost. However, unit costs of most materials supplied by home such as cement, steel, cables and carbon steel pipes, etc. being relatively cheaper than those of abroad, their effects on material-to-equipment ratios are apparent. There is a deep difference in labor wage rates between Korea and U.S.A. as much as 16 times. However, the labor productivity observed in these model projects is in the range of 1.1-1.4 to the Gulf Coast, U.S.A. during the same period. And this low wage rate and relatively high productivity have the greatest influence on deviation of Korean cost structure from that of U.S.A. In these model projects, engineering and construction management was conducted by foreign contractors (mostly U.S.A.), and the resulting project indirect cost amounts to 7.5 times as high as most cases executed by Korean contractors alone. Weighted percentage of each component and L/M-ratio by activities of direct field cost derived from this analysis are shown in detail in Tables 2 and 5 to provide a basis for futher study and comparison.

• 한국전기전자재료학회논문지
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• 제35권5호
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• pp.466-470
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• 2022

In order to widely disseminate LED lighting, LED lighting technology that directly uses AC commercial power has been recently introduced. AC powered LED lighting technology has a problem in that the light brightness of the LED changes because the voltage applied to the LED and the current flowing through the LED continuously change. In this study, when the LED current is greater than the design current, the current control signal generated by the controller is supplied to the current source to supply only the design current to the LED by increasing the voltage drop at the current source. If it is smaller than the design current, the controller is adjusted so that the current is supplied only to the LED without a voltage drop in the current source. It can be seen that the higher the maximum rectified voltage, the faster the lighting time of the LED light emitting block is, so that the power factor of the LED lighting is improved. The LED lighting technology proposed in this study enables LED lighting with constant light brightness, reduced power consumption, and long lifetime.