• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.283.2-283.2
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• 2002

Organochlorine pesticides and polychlorinated biphenyls (PCBs) have been used intensively in agriculture and industry for a long time. They belong to a group of contaminants whose occurrence in the environment is a serious concern to environmental chemists and toxicologists due to their resistance to degradation in the environment as well as their potential toxicity. Also. the lipophilic characteristics of these substances are responsible for their ability to bioaccumulate in tissues and organs rich in lipids of men and animals through food chain. Therefore, the measure of the levels of organochlorine pesticides and PCBs in human tissues are good markers in detemining the extent to exposure and evaluating the hazards. This study was preformed to compare concentrations of organochlorine pesticides(${\alpha}-BHC, {\beta}-BHC, {\gamma}-BHC, {\delta}-BHC$, p.p'-DDT,p.p'-DDD,p.p.'-DDE. endrin. dieldrin. aldrin) and seven marker PCBs(PCB nos. 28. 52. 101. 118. 138. 153. 180) in liver. kidney cortex, lung blood and adipose tissue collected at autopsies of 10men and 10 women using gas chromatography equipped with electron capture detector to express the data on a lipid adjusted basis. From the results, the significant differences in the levels of organochlorines of PCBs between sexes, districts where they had lived and ages were also investigated.

• 한국화재소방학회논문지
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• 제14권2호
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• pp.33-38
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• 2000

전자산업의 공정에서 PCB기판납땜은 괼수적이며 이에 사용하는 Flux내 용제인 IPA(Iso--propyl alcohol)와 메탄올은 인화성과 폭발성이 강한 물질로 화재위험성이 대단히 높다. 또한 메탄올은 유독성물질로 지정되어 있으며, 환경법상 VOC(Volatile Organic Compound : 휘발성유기화합물)규제물질로 지정되어 있어 대체물질 개발이 절실히 요구된다. 이에 기존 Flux특성을 가지고 있으면서 화재위험성은 없고, 휘발성유기화합물 규제물질에는 해당되지 않는 디클로로프로판(Dichloropropane, DCP)를 주성분으로 하여 Flux 특성에 맞는 안정제 및 첨가제를 적정 조성비로 조합하여 용제를 개발하였다. 그 결과 200ppm의 작업환경허용농도를 470 ppm으로 완화시킬 수 있었으며 납땜불량율은 0.083%에서 0%로, 퍼짐성은 85%에서 87%로, 전연저항은 1.0$\times$$10^{12}$$\Omega$에서 6.9$\times$$10^{12}$/$\Omega$으로 기존 Flux보다 우수하였다. 그러므로 Flux의 안정성은 물론 환경안전측면과 품질, 생산성도 향상이 가능함을 확인하였고, 품질 특성시험 및 제품 신뢰성 시험 결과 만족할 만한 곁과를 얻었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.504-509
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• 1994

Recently SMT is used widely to place the SMD on bare board which is very small and highly integrated. And that is one of the issue directly in the electric products assembly process and especiallly in the field of optimizing electric product's performance, automatically tuning method which is highly demanded in the electronics industry. To tune product's performance, variable resistances's resistivity should be changed until it has good performance characteristics. In this paper to automatically regulate the 8mm camcoder's performance, it is proposed variable resistence's center position and orientation detection algorithm by image processing, which has very precise and accurate result. And we found optimal conditions which can have effects on image acquisition process. And real time processing is done by DSP to detect vr's center and orientation. This results make it possible to utilize proposed image processing algorithm and system directly in electronics industry.

• 한국산업융합학회 논문집
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• 제4권3호
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• pp.289-294
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• 2001

In this paper a POCSAG receiver interface circuit for wireless remote control using pager system is presented. SM8212A and AT89C51 chips are used for the core of system design. The proposed system is able to communicate with computers through RS-232C interface, which enables users to manage the data from the pager system on computers in real time. Analysis of SM8212A for Ole algorithm of CPU control program is described. The hardware is implemented on a PCB and the control program is made by C++ and assembly language. The performance of designed system is confirmed by experiments using the TESCOM equipments.

• 한국산업융합학회 논문집
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• 제12권4호
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• pp.215-219
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• 2009

A packaging technology based on flip-chip bonding and Pb-free solder for silicon pressure sensors on printed circuit board (PCB) is presented. First, the bump formation process was conducted by Pb-free solder. Ag-Sn-Cu solder and the pressed-screen printing method were used to fabricate solder bumps. The fabricated solder bumps had $189-223{\mu}m$ width, $120-160{\mu}m$ thickness, and 5.4-6.9 standard deviation. Also, shear tests was conducted to measure the bump shear strength by a Dage 2400 PC shear tester; the average shear strength was 74 g at 0.125 mm/s of test speed and $5{\mu}m$ shear height. Then, silicon pressure sensor packaging was implemented using the Pb-free solder and bump formation process. The characteristics of the pressure sensor were analogous to the results obtained when the pressure sensor dice are assembled and packaged using the standard wire-bonding technique.

• 한국산업융합학회 논문집
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• 제20권2호
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• pp.187-194
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• 2017

This study examined the validity and reliability of the thermal safety design, in order to maintain the heat generated from integrated circuit (IC) chips in the converter, condenser, resistor, and transistor (which are considered as heat sources for thermoelectric devices with a printed circuit board) below target levels during the process of developing a control board and a main power board. The study analyzed the heat generation and dissipation characteristics of the entire printed circuit board (PCB) model to examine its thermal safety.

• 멤브레인
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• 제23권1호
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• pp.92-99
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• 2013

본 연구는 인쇄회로기판(PCB) 제조 시 에칭공정에서 발생되는 구리이온($Cu^{+2}$)을 고농도로 함유한 황산 폐에칭액을 NF 막분리법을 사용하여 에칭액 회수와 구리이온 처리를 효율적으로 수행하기 위한 NF 막여과 공정의 운전 조건을 설정하기 위한 기본 자료를 확보하는데 있다. 이를 위해 미국 Koch사의 SelRO MPS-34 4040 NF 막을 대상으로 구리이온을 고농도(5~25 g/L)로 함유한 모의 황산 폐에칭액의 회분식(dead-end) 나노여과 실험을 수행하여 투과 플럭스와 구리이온의 총괄 배제도를 측정하였다. 이 결과 황산용액에의 막 보관기간이 길수록, 황산용액의 pH가 낮을수록 황산에 의한 NF 막의 손상이 더 크게 발생하여 순수 투과 플러스가 증가하였다. 황산 폐에칭액의 투과 플럭스는 황산용액 내 구리이온의 농도가 증가할수록 막 표면에의 구리이온 농축(농도분극)의 증가에 따라 감소하였으며, 구리이온의 배제도는 구리이온의 농도가 높을수록, pH가 낮을수록, 황산용액 내의 막 보관기간이 길수록 낮아져 초기 37%에서 최소 15% 수준으로까지 감소하였다.

• 청정기술
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• 제17권4호
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• pp.306-313
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• 2011

인쇄회로기판(PCB)과 같은 전자부품을 제조시에 솔더링을 하기 위하여 플럭스나 솔더페이스트를 사용하며 솔더링 후에 부품에 잔류한 플럭스나 솔더페이스트를 제거하여야하는데 이것은 이들 물질이 잔류하였을 경우 부식이나 누전을 초래하여 부품의 성능을 떨어뜨리거나 고장을 일으킬 수 있다. 솔더링 후에 플럭스와 솔더플럭스 잔류물을 제거하기 위하여 오존파괴물질 세정제인 1,1,1-trichloroethane이나 HCFC-141b가 아직까지 많이 사용되고 있다. 본 연구에서는 이들 오존파괴성질을 가진 세정제를 대체하기 위하여 인화점이 존재하지 않는 비수계세정제를 개발하였고 산업현장 적용도 시도해 보았다. 인화점이 존재하지 않는 세정제를 개발하기 위해 탄화수소계 용제를 주 용제로 하고 글리콜에테르계, 에스테르계 및 불소계 용제를 첨가하여 비수계세정제를 배합하였고 이들의 물성 및 세정성을 평가하였다. 그리고 이들 배합세정제 중에 세정력이 뛰어난 세정제를 현장에 적용하여 보았다. 또한 배합된 비수계세정제의 사용후에 재활용 가능성을 평가하기 위하여 감압증류장치를 가동하여 사용 후의 세정제를 재활용시에 요구되는 운전 조건과 재활용율을 구하여 보았다. 배합세정제의 물성 측정 결과 모두 표면장력이 18.0~20.4 dyne/cm으로 비교적 낮았고 습윤지수도 비교적 높아 오염물에 대한 습윤력과 침투력이 우수할 것으로 기대되었고 불소계용제를 첨가하여 배합한 세정제는 인화성이 없음이 확인되어 사용하고 보관하기에 안전하리라 사료된다. 플럭스 및 솔더페이스트 세정 연구 실험 결과 대체목표세정제인 1,1,1-TCE와 HCFC-141b보다 세정력이 우수함을 확인할 수 있었다. 그리고 배합세정제 중에 우수한 세정제를 선정하여 HCFC-141b를 사용하는 산업현장의 PCB 세정에 적용한 결과 HCFC-141b보다 우수한 세정을 나타내어 산업현장에 적용 가능성을 보여 주었다. 또한 이들 제품을 감압증류장치를 이용하여 재활용 가능성을 평가 결과 운전조건 $100{\sim}110^{\circ}C$, 20~30 mbar에서 91.9~97.5%를 재활용할 수 있음을 보여주었다.

• Environmental Analysis Health and Toxicology
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• 제19권2호
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• pp.227-233
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• 2004

The main objectives of this study were to identify from literature review the potential sources and to provide a preliminary national emission inventory for the unintentionally produced polychlorinated biphenyls (PCBs) (i.e., by - product PCBs). In Korea, fuel combustion, waste combustion, thermal industrial processes, and transportation were identified as potential sources of by -product PCB s. According to the availability of the emission factors and/or activity data, emission inventory could be assessed only for fuel combustion, waste combustion, steel industry, non-ferrous industry, and non-metallurgical industry. The total national emission of by-product PCBs was estimated to be 1087kg for the year 2000. The preliminary estimation further indicated that the steel manufacturing was the single dominant emission category, contributing 93％ to the total emission. Of the steel manufacturing processes, the contribution of the electric arc furnace was about 80％ of the total emission. Due to high uncertainty associated with both the emission factors and activity statistics, the emission estimates in this study are likely to contain significant errors. However, the results of the present work could serve the first step toward future efforts to establish national source and emission inventories of by-product PCBs.

• 한국산업융합학회 논문집
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• 제22권3호
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• pp.373-379
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• 2019

Nowadays, the IoT portable electronic devices have become more useful and diverse, so they require various supply voltage levels to operate. This paper presents a DC-DC buck converter with pulse width modulation (PWM) for portable electronic devices. The proposed step-down DC-DC converter consists of passive elements such as capacitors, inductors, and resistors and an integrated chip (IC) for signal control to reduce power consumption and improves ripple voltage with the resolution. The proposed DC-DC converter is simulated and analyzed in PSPICE circuit design platform, and implemented on the prototype PCB board with a Texas Instruments LM5165 IC. The proposed buck converter is showed 92.6% of peak efficiency including a load current range of 4-10 mA, 3.29 mV of the voltage ripple at 5 V output voltage for the supply voltage 12 V. Measured and Simulated power efficiency are made good agreement with each other.