• 한국전기전자재료학회논문지
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• 제28권1호
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• pp.57-63
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• 2015

Recently, LED is widely used in the kinds of display devices or lighting. In this paper, we fabricated LED chamber light for naval vessels to replace to conventional chamber light using incandescent lamp. The LED package of chamber light was designed with luminous intensity of 5.5 cd, color temperature of $6,000{\pm}500K$, forward voltage of 3~3.2 V and input current of 60 mA. A LED module was composed of 36 LED packages and metal PCB. The VF and luminous intensity of LED package were getting down when temperature increased. The temperature of LED chamber light was measured by changing the number of LED package and applied current for one hour when an electric current flow. The heat transfer capability have been improved by using metal PCB. The power consumption of LED chamber light reduced by 86% compared to the conventional chamber light using incandescent lamp.

• 한국광학회:학술대회논문집
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• 한국광학회 2009년도 동계학술발표회 논문집
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• pp.147-148
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• 2009

We have fabricated a down tapered polymer tip on optical fiber end-face by a guided UV light. One side of fiber was aligned with a mercury-xenon lamp and another was put into UV curable polymer. A shape of tip was controlled by adjusting an irradiance of lamp and time of exposure. A bending effect also affects the result. Optical characteristic was achieved preliminarily with solution of minute particles.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.915-923
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• 2011

Our country is promoting the introduction of new means of transportation due to insufficient supply according to the existing demand of road traffic. Among them, manless light railroad transit is settled down as the most definite alternative. However, new traffic systems such as manless light railroad have certain difference between characteristics of hardware and software and subway system. Therefore, there will be many differences compared to the existing contingency system when accidents occur. Railway management organization has to establish railway contingency plan and acquire permission from the minister of the Ministry of Land, Transport, and Maritime Affairs. However, as commercial transportation is available, a new traffic system also should establish contingency plan. Therefore, the establishment of systematic contingency plan is suggested in order to analyze characteristics of manless light railroad in the beginning of introduction and to make contingency response available.

• 반도체디스플레이기술학회지
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• 제3권4호
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• pp.45-49
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• 2004

We examined large particles and filter size effects of Central Chemical Supplying (CCS) system for STI-CMP on Light Point Defects (LPDs) after polishing. As manufacturing process recently gets thinner below 0.1 um line width, it is very important to keep down post-CMP micro-scratch and LPDs in case of STI-CMP. Therefore, we must control the size distribution of large particles in a slurry. With optimization of final filter size, CCS system is one of the solutions for this issue. The oxide and nitride CMP tests were accomplished using nano-ceria slurries made by ourselves. The number of large particles in a slurry and the number of LPDs on the wafer surface after CMP were reduced with decrease of the final filter size. Oxide removal rates slightly changed according to the final filter size, showing the good performance of self-made nano ceria slurries.

• 한국철도학회논문집
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• 제9권1호
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• pp.23-28
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• 2006

Many services have been served by the exiting subway systems since they have opened in 1975. But its efficiency and competition were going down because of the high construction cost and difficult connection with other transportations, etc. Otherwise, the light rail transit system is much lower construction cost than the subway and the high way building. Also those systems are good at the inexpensive operation cost, the fixed time and safety, the easy access. Recently, the several provinces are planning or advancing the light rail transit system because of these many benefits. Consequently, those system's economical feasibility analysis is required rapidly to show the resonable construction's cause and to get the private investment. This paper offers the system's economical feasibility through the several benefit analysis after the light rail transit system's construction.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1993년도 제5회 학술발표회 논문개요집
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• pp.39-39
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• 1993

A finite element analysis and Monte Carlo method have been applied to calculate the ppressure pprofiles around the ppohang Light Source (ppLS) electron storage ring with the aim of ppredicting the pperformance of the vacuum system designed for the ppLS vacuum system. After ppropperly choosing the design pparameters, the ppressure distribution are calculated as a function of the integrated stored beam current [AmppHrs]. The effect of changes of the vacuum pparameters, such as installed ppumpping sppeeds and synchrotron radiation induced gas desorpption rates on the ppressure pprofile, is also studied. The results indicate that the use of lumpped non-evapporable getter ppumpps together with spputter ion ppumpps for ppumpping the ppLS down to the required ppressure is ppossible in the ppresence of synchrotron induced gas loads, after resonable beam cleaning time.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.92-92
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• 2010

Replacing the existing illumination with solid-state lighting devices, such as light-emitting diodes (LEDs) are expected to reduce energy consumption and environmental pollution as they provide better efficiency and longer lifetimes. Currently, white light emitting diodes are composed of UV or blue LED with down-converting materials such as highly luminescent phosphors White light-emitting diodes (LED) were fabricated with multi-shell nanocrystal quantum dots for enhanced luminance and improved stability over time. Multi-shell quantum dots (QDs) were synthesized through one pot process by using the Successive Ionic Layer Adsorption and Reaction (SILAR) method. As prepared, the multi-shell QD has cubic lattice of zinc-blend structure with semi-spherical shape with quantum yield of higher than 60 % in solution. Further, highly fluorescent multi-shell QD was deposited on the blue LED, which resulted in QD-based white LED with high luminance with excellent color rendering properties.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전기물성,응용부문
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• pp.273-275
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• 2003

본 실험은 고출력 반도체 레이저의 p-side-down 마운팅용 솔더로서 AuSn 합금 솔더(80wt%:20wt%)의 적합성에 대해 연구하였다. $1{\mu}m$이하의 균일도로 폴리싱 된 Cu heat sink의 표면에 두께 $1{\mu}m$의 Ni로 코팅을 한다음, AuSn 다층박막은 e-beam 증착기로 AuSn 합금 솔더는 열증착기로 각각 증착하였다. 열처리는 산화 방지를 위해 $N_2$ 분위기에서 행하였으며, 동일한 압력으로 마운팅을 하였다. 표면의 거칠기와 형상은 AFM(Atomic Force Microscope)과 SEM(Scanning Electron Microscopy)으로 그리고 Au와 Sn의 성분비는 AES(Auger Electron Spectroscopy) 로 비교하였다. 또한 CW(연속발진)을 통한 L-I(Light-Current)측정을 통해 본딩상태를 비교하였다.

• Applied Microscopy
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• 제24권4호
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• pp.52-60
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• 1994

The developing ovarian oocyte of Dendrolimus spectabilis has been studied by using electron microscopical techniques. After yolk formation the vitelline membrane was laid down in the intercellular space between the follicle cell and the oocyte. But before the vitelline membrane formation the granules with high electron density that the vitelline membrane precusor are observed in the follicle cell. At the late vitellogenesis stage these granules were transported into the intercellular space between the follicle cells and the oocyte. These granules fuse to each other and larger bodies which eventually produce the vitelline membrane. The vitelline membrane was distinguished into the light inner and dark outer membrane. Next the chorion was laid down. It was apparent that the chorion was laid down in the intercellular space immediately adjacent to the vitelline membrane, and that it was formed by the follicle cells only.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 추계학술대회 논문집
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• pp.263-266
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• 2003

The high power factor converters are classified step-up, step-up-down and step-down converter, The power conversion system must be increased switching frequency in order to achieve a small size, a light weight and a low noise. And the power system brings on a high efficiency and high power factor. When a switch of the step down converter is operated with a commercial frequency(60Hz), a reactor using the converter is gone with a great number of harmonics waveforms of low grade. As results of this, the converter is decreased input power factor and is increased system size. To improved these, this paper proposes a PSM(Pulse Size Modulation) control strategy operated with high power factor.