• 한국정보통신학회논문지
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• 제11권9호
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• pp.1717-1723
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• 2007

본 연구에서는 PLZT(10/30/70), PLT(10), PZT(30/70) 강유전체 박막을 이용한 quasi-MFISFET (Metal-Ferroelectric-Insulator-Semiconductor FET) 소자를 제작하여 드레인 전류 특성을 조사하였다. 이로부터, quasi-MHSFET 소자의 드레인 전류 크기가 강유전체 박막의 분극 크기에 따라 직접적인 영향을 받으며 결정된다는 사실을 알 수 있었다. 또, ${\pm}5V$ 와 ${\pm}10V$의 게이트 전압변화를 주었을 때 메모리 윈도우는 각각 0.5V 와 1.3V 이었고, 강유전체 박막에 인가되는 전압에 의해 만들어지는 항전압의 변동에 따라 메모리 윈도우가 변화된다는 사실을 확인할 수 있었다. MFISFET 소자의 retention 특성을 알아보기 위 해 PLZT(10/30/70) 박막의 전기장과 시간지연에 따른 누설전류 특성을 측정하여 전류밀도 상수 $J_{ETO}$, 전기장 의존 요소 K, 시간 의존 요소 m을 구하고, 이들 파라미터를 이용하여 시간에 따른 전하밀도의 변화를 정량적으로 분석하였다.

• Bulletin of the Korean Chemical Society
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• 제34권7호
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• pp.2056-2062
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• 2013

The dihydroxy naphthalene/$TiO_2$ complexes with different substitution patterns were prepared by surface modification. X-ray diffraction, UV-Vis spectroscopy, photoluminescence, and X-ray photoelectron spectroscopy were used to characterize the prepared composite materials. The results indicated that the surface modification did not influence the crystallization of $TiO_2$. The visible-light absorbances of prepared dihydroxy naphthalene/$TiO_2$ complexes could be assigned to the ligand-to-metal charge transfer. The obtained catalyst exhibited outstanding photocatalytic activity and stability under visible light. A linear relationship existed between the percentages of hydroxynaphthalenes coordinated on $TiO_2$ surface and $H_2$ production ability. The substitution pattern of dihydroxy naphthalene and $CH_3OH$ content could also influence the photocatalytic performance remarkably. The photocatalytic $H_2$ production ability was further improved after loading with ultra low concentration of Pt, 0.02 wt %. The possible mechanism was proposed.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.431-432
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• 2012

In the era of 20 nm scaled semiconductor volume manufacturing, Microelectronics Manufacturing Engineering Education is presented in this paper. The purpose of microelectronic engineering education is to educate engineers to work in the semiconductor industry; it is therefore should be considered even before than technology development. Three Microelectronics Manufacturing Engineering related courses are introduced, and how undergraduate students acquired hands-on experience on Microelectronics fabrication and manufacturing. Conventionally employed wire bonding was recognized as not only an additional parasitic source in high-frequency mobile applications due to the increased inductance caused from the wiring loop, but also a huddle for minimizing IC packaging footprint. To alleviate the concerns, chip bumping technologies such as flip chip bumping and pillar bumping have been suggested as promising chip assembly methods to provide high-density interconnects and lower signal propagation delay [1,2]. Aluminum as metal interconnecting material over the decades in integrated circuits (ICs) manufacturing has been rapidly replaced with copper in majority IC products. A single copper metal layer with various test patterns of lines and vias and $400{\mu}m$ by $400{\mu}m$ interconnected pads are formed. Mask M1 allows metal interconnection patterns on 4" wafers with AZ1512 positive tone photoresist, and Cu/TiN/Ti layers are wet etched in two steps. We employed WPR, a thick patternable negative photoresist, manufactured by JSR Corp., which is specifically developed as dielectric material for multi- chip packaging (MCP) and package-on-package (PoP). Spin-coating at 1,000 rpm, i-line UV exposure, and 1 hour curing at $110^{\circ}C$ allows about $25{\mu}m$ thick passivation layer before performing wafer level soldering. Conventional Si3N4 passivation between Cu and WPR layer using plasma CVD can be an optional. To practice the board level flip chip assembly, individual students draw their own fan-outs of 40 rectangle pads using Eagle CAD, a free PCB artwork EDA. Individuals then transfer the test circuitry on a blank CCFL board followed by Cu etching and solder mask processes. Negative dry film resist (DFR), Accimage$^{(R)}$, manufactured by Kolon Industries, Inc., was used for solder resist for ball grid array (BGA). We demonstrated how Microelectronics Manufacturing Engineering education has been performed by presenting brief intermediate by-product from undergraduate and graduate students. Microelectronics Manufacturing Engineering, once again, is to educating engineers to actively work in the area of semiconductor manufacturing. Through one semester senior level hands-on laboratory course, participating students will have clearer understanding on microelectronics manufacturing and realized the importance of manufacturing yield in practice.

• 한국통신학회논문지
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• 제38C권8호
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• pp.725-732
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• 2013

최근 LED의 저전력, 장수명, 동작 속도, 제어성, 고품질의 색 연출성, 지속 가능성 등의 이유로, LED 응용 분야가 확대되고 있다. 그러나 고출력 LED 조명 시스템을 구현하는데 있어, 방열은 큰 걸림돌이 되고 있다. 본 논문에서는 고출력 투광등 설계를 위한 방열 방안으로 메탈 PCB 설계, 열전 소자, 히트 파이프, 방열판, 팬(fan) 등의 적층 연동 구조를 제안하고 구현 방안을 제시하였다. 아울러 본 논문에서는 RS-485 통신을 통한 DMX512 프로토콜 기반 LED 조명 시스템 제어 방안을 제시하였다. DMX512 프로토콜은 조명장치와 조명제어 모듈의 연결에 대한 사실상 세계적 표준이며 이를 활용한 무대 조명이나 경관 조명 시스템 개발이 지속적으로 이루지고 있다. 본 논문에서는 이를 이용한 LED 조명 제어 및 응용 기술을 소개하고 주제어기를 무선으로 원격 제어하는 방안을 제안하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.624-627
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• 2001

Two kinds of Nd$_{1+x}$Ba$_{2-x}$Cu$_3$O$_{7-{\delta}}$, the sintering samples and zone melting samples, were heat treated under pure Ar at 95$0^{\circ}C$. The substitution of Nd ion for Ba ion in the Nd$_{1+x}$Ba$_{2-x}$Cu$_3$O$_{7-{\delta}}$ before and after the heat treatment were investigated by XRD. In order to know the effects of the heat treatment, the T$_{c}$ and J$_{c}$ of samples with the heat treatment and those without the heat treatment by Ar were comparatively studied. The results show that the substitution of Nd for Ba decreased, T$_{c}$, and J$_{c}$ increased after the treatment under Ar at 95$0^{\circ}C$. The Nd$_{1+x}$Ba$_{2-x}$Cu$_3$O$_{7-{\delta}}$ samples were oxygenated under pure oxygen at 30$0^{\circ}C$. From the XRD pattern it was found that the sample with x< 0.4 could transfer from tetragonal phase to orthorhombic phase after the oxygenation, but the sample with x>0.4 could not make the phase transition even after a long time oxygenation.ion even after a long time oxygenation.ation.n.ation.ation.

• 한국산업보건학회지
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• 제15권3호
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• pp.166-175
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• 2005

Health effects associated with metal working fluid (MWF) exposures include dermatitis, respiratory disease, hypersensitive pneumonitis, and asthma. Frequently, occupational exposures to MWFs are controlled by ventilating an enclosure with an air cleaning unit that includes a fan preceded by various kinds of filtration. There are several kinds of air cleaning units used in machining centers. But the associated troubles have hindered from efficiently using these devices. The main problem is the relatively short period of filter replacement. The reason is that the air cleaning units usually do not have the de-oiling systems, thus leading the earlier clogging of filters and reducing the flow rate of hood. Thus, the first stage of study was conducted to overcome this problem by developing the new oil mist collector equipped with the easy de-oiling system. The principle of de-oiling is that the centrifugal force generated by spinning the drum covered by filter fabric separates oils from the filter fabric. It would be very similar to the spin-dry laundry. By adopting this de-oiling technique, the problems associated with the conventional oil mist collectors could be solved. Several tests/analyses were performed to make the lab-scale oil mist collector. The collection efficiencies and the de-oiling efficiencies of commercially available filter fabrics were tested. Subsequently, the endurance test were conducted by observing SEM photos of filter fabrics and measuring tensile strength/expansion coefficient after spinning the filter drum for 20 minutes at the different rotation speeds. By doing these experiments, the most appropriate filter fabric and rotation speed/duration were selected. Finally, the new oil mist collector was designed. In the near future, this device must be tested in the real machining center.

• 한국전기전자재료학회논문지
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• 제31권4호
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• pp.267-271
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• 2018

A high directivity TIR (total internal reflection) lens in the UV-A region was designed using a silicone resin, and a UV light source module with a maximum irradiation density of $150mW/cm^2$ was fabricated. The beam angle of the TIR lens was designed to be $8.04^{\circ}$ and the maximum diameter of the TIR lens was Ø13.5. A silicone resin having a UV transmittance of 93% and a refractive index of 1.4 at a wavelength of 365 nm was used, and the lens was manufactured using an aluminum mold, from which silicone could be easily released. The module was fabricated in a metal printed circuit board of COB (chip on board) type using a $0.75{\times}0.75mm^2$ UV chip. A jig was used to adjust the focal length between lens and chip and to fix the position of the lens. The optical characteristics such as illumination distributions of the lens and module were designed using 'LightTools' optical simulation software. The heat dissipation system was designed to use a forced-air cooling method using a heat-sink and fan.

• 복식
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• 제33권
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• pp.117-142
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• 1997

This study is on perfume case that is one of a great number of ornaments which was designed by out ancestors. We had developed the tradition and the history of perfume case bag fan-weight etc. These have the same function as the present perfume. case. There were basket-shaped perfume cases which were the smellest one among the personal girdle ornaments in the silla era. The various patterned perfume case were made of gold metal coral platinum or green jadeite etc. In the single-crop trinkets a embroidered perfume bag with the gold and silver thread whose forms perfectly match their functions appeared during the Yi Dynasty. There was also a perfume bag which was one of the daily necessities. A precious "jul perfume" was carried by noble women. A fan-weight perfume bag was attached to the fan to emphasize the intrinsic beauty of utility and function. It is necessary to know the function of prefume case. As perfume case is weared on the clothes it was given more decorative effects as well as the function of medicinal amulet with a sweet smell. Therefore it is very important for us to study perfume case that has various function as an ornament. So The purpose of this study is to investigate the practical and decorative side of perfume case with the general examines of perfume finding how to practice use through our life. The results were as follows; 1. The first use of perfume is perfume through smoke which is for ceremony of religion It removes human body odor by degrees and spreads a sweet odor. Also the materials for making perfume of early age is aromatic plants which will be used flour-made flowers stems. As the materials for making perfume use is increasing today we can invent alcohol perfume today 2. Our country the custom of perfume-used is wide. Among them men's perfume-used was very special phenomenon. For example men were wearing perfume bag in the Silla era. Because perfume represented wealth and noble in those days. They shew off social position personality through perfume-used. 3. One of early religion ceremony article there was the perfume. And perfume case was means for containing perfume. Gradually the perfume case was used widly as increasing needs of perfume in human life. 4. In the middle period of 'Koryo' Dynasty perfume cases had a close relationship with clothes but after Mongolian has been attacked 'Koryo' there were changes in wearing clothes therefore the position of perfume cases were transfered to coat string that was the origin of decoration style that they began. That is to say the perfume case has been influenced the position of perfume case shapes with changing of fashion. 5. The perfume case has been made manifest various function as an ornament. In the practical side First medical-perfume in perfume case has been played an important role in first-aid medicine in critical condition. Second it was amulet for self protection. That is the shape pattern color materials perfume of the perfume case was represented the amuletive nature. Third it was used as substitute article of perfume. Modern women use liquid-perfume as our ancestors used perfume case bag or jul perfume As started above. Also In the decorative side the perfume case has a beautiful formative arts by itself as well as a close relationship with clothes. That well as a close relationship with clothes. That is when the perfume case is worn on the clothes costume is showed aesthetices. That is the materials shapes color pattern of the perfume case we can see the visual beauty also the materials colors embroidered pattern knots tassel that are used the perfume case are increased the decorative beauty of costume. Sixth the symbol in pattern of the pattern case is shown ancetor's wealth and rank health longevity immortality many-born-boy in those days. Today the perfume case is not used with changing of costume by degrees, Accordingly I hope that the result of this study is an influened in devlopment of the perfume case design with matching the modern fashion.

• Composites Research
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• 제33권5호
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• pp.275-281
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• 2020

본 논문에서는 항공기 팬 블레이드에 적용되는 복합재와 금속 간의 접합 구조물에 대한 온도, 습도에 따른 접착제의 물성 변화에 관해 연구하였다. 항공기 운용 시 노출되는 환경 조건을 고려하여 상온 건조(Room Temperature Dry, RTD), 고온 흡습(Evaluated Temperature Wet, ETW), 저온 건조(Cold Temperature Dry, CTD) 세가지 환경에서 강도 시험을 수행하였다. 접착전단강도 시험은 ASTM D3528을 기준으로 수행하였고, 파손 영역에 대한 마이크로 구조 특성을 SEM이미지를 통해 분석하였다. 연구 결과에 따르면 RTD 환경에서의 전단강도 대비하여 ETW 환경에서 72.8% 저하되었으며, CTD 환경에서는 56.5% 증가되었다. 이는 고온 및 수분 흡습이 접착제의 기계적 특성에 큰 영향을 미치는 것을 확인했고, 저온 환경에서는 모재와 접착제 모두 취성의 증가로 인해 접착 전단 강도가 향상된 것으로 분석되었다.

• 한국구조물진단유지관리공학회 논문집
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• 제24권2호
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• pp.9-14
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• 2020

필터가 장착 된 먼지 감소 팬을 포함하여 새로운 유형의 Composite Cyclone Scrubber를 개발하고, 목표 설치 및 유지 보수 비용에 대해서는 기존 도로 오염 저감 시스템 대비 64 %의 투자비 절감 (61 억 원 vs. 170 억 원), 기존 도로 오염 저감 조치 (72.6 억 원) 대비 사회적 비용편익이 43 % 증가, 50.8 억 원)가 예측되고 있다. 장치의 구성은 송풍기 형 나선형 가이드 베인이며, 분사 압력은 미세먼지를 포집한다. 분사 각도 및 접촉 범위가 다양한 노즐, 스프레이 액체 등과 순환 수를 이용한 스프레이이며, 분사 된 물이 Guide Vane과 45도 각도로 충돌로 인해 오염된 가스를 만나기 때문에 41.4 % 더 많은 미세 먼지를 포집한다. 이는 기존의 집진기보다 141 % 증가한 것이다. 포집 액체, 순환 빗물 및 우물 공급원과 관련하여 우리는 특허에서 막대한 양의 에너지와 경제적으로 절약되는 친환경 시스템을 기대한다. 가이드 베인 및 금속 필터는 90 % 이상의 미세 먼지를 줄였으며, 분무 된 물은 베인과 필터를 청소하여 유지 관리 예산을 최소화했다. 개발 된 설계의 예비 평가를 통해 특징적인 물분사로 인하여 유지 보수 예산을 줄일 수 있다.