• Journal of Astronomy and Space Sciences
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• 제31권2호
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• pp.177-186
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• 2014

The Immersion Grating Infrared Spectrometer (IGRINS) is a near-infrared wide-band high-resolution spectrograph jointly developed by the Korea Astronomy and Space Science Institute and the University of Texas at Austin. IGRINS employs three HAWAII-2RG Focal Plane Array (H2RG FPA) detectors. We present the design and fabrication of the detector mount for the H2RG detector. The detector mount consists of a detector housing, an ASIC housing, a Field Flattener Lens (FFL) mount, and a support base frame. The detector and the ASIC housing should be kept at 65 K and the support base frame at 130 K. Therefore they are thermally isolated by the support made of GFRP material. The detector mount is designed so that it has features of fine adjusting the position of the detector surface in the optical axis and of fine adjusting yaw and pitch angles in order to utilize as an optical system alignment compensator. We optimized the structural stability and thermal characteristics of the mount design using computer-aided 3D modeling and finite element analysis. Based on the structural and thermal analysis, the designed detector mount meets an optical stability tolerance and system thermal requirements. Actual detector mount fabricated based on the design has been installed into the IGRINS cryostat and successfully passed a vacuum test and a cold test.

• 대한기계학회논문집
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• 제12권3호
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• pp.440-449
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• 1988

본 연구에서는 미소한 진동진폭의 정밀한 측정을 위해 비교적 광선정렬(opti- cal alignment)이 쉽고 광손실이 적으며 국소부위의 진동측정이 가능한 다중반사계를 Michelson간섭계에 도입하였다.미소 진동진폭의 정밀한 값을 결정하기 위해서는 간 섭신호를 측정하여 간섭무늬 보간법과 곡선 맞춤법을 이용하는 방법이 있다. 전자는 간단한 계산과 시간을 절약할 수 있는 반면 후자는 복잡한 계산으로 인해 많은 시간이 소요된다. 그러나 정밀계측장비의 교정에서와 같이 경우에 따라서는 많은 시간과 노 력이 소요되더라도 정밀한 측정결과를 얻어야할 필요가 있기 때문에 이들 두가지 방법 의 정밀도를 확인하기 위해 컴퓨터에 의한 모의실험을 수행하였다.

• 한국자동차공학회논문집
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• 제15권1호
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• pp.116-124
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• 2007

An optical method to measure the size and number density of soot aggregates in diesel exhaust has been proposed in this study. Two laser beams in co-axial alignment transmit a soot loaded exhaust gas flow, and the transmittance at each wavelength is detected by a photo diode simultaneously. The volume equivalent diameter and number density of soot aggregates in the optical path can be theoretically given by the transmittance values measured at two wavelengths. A test conducted by a single cylinder, 4 cycle, small and DI diesel engine shows that the temporal variations of the size and number density of soot aggregates in the diesel exhaust can be measured by the proposed method at a transient mode operation. It is found that the volume equivalent diameter varied temporally from 70 to 110 nm during the period that high soot concentration is observed. One can also conclude that the optical length longer than 1 m in the dynamic range regarding this method is preferable for measuring soot concentration at the level of $1\;mg/m^3$.

• KSBB Journal
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• 제20권4호
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• pp.311-316
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• 2005

EH의 catalytic nucleophile residue, His-Asp로 구성된 charge relay system, oxyanion hole 등의 EH 관련 conserved domain의 아미노산 공통 서열을 참고로 하여 G. westfalica megaplasmid로부터 putative EH를 선별할 수 있었다. Bioinformatics를 기반으로 스크리닝한 G. westfalica에 의한 라세믹 styrene oxide 기질에 대한 입체선택성 가수분해 반응에 있어 중요 반응 parameter들인, pH 및 온도 등이 초기 가수분해반응속도에 미치는 영향을 분석하고, 최적 회분식 반응조건을 결정하였다. 최적 반응조건인 pH 7, 반응 온도 $30^{\circ}C$, 생촉매량 40 mg의 조건에서 약 5시간 20분간 반응을 통해 20 mM 라세믹 기질로부터 광학순도 $100\%$ ee인 (S)-styrene oxide를 $36.5\%$의 수율로 얻을 수 있었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.95-95
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• 2014

An OLED(Organic Light-Emitting Diode) device based on the emissive electroluminescent layer a film of organic materials. OLED is used for many electronic devices such as TV, mobile phones, handheld games consoles. ULVAC's mass production systems are indispensable to the manufacturing of OLED device. ULVAC is a manufacturer and worldwide supplier of equipment and vacuum systems for the OLED, LCD, Semiconductor, Electronics, Optical device and related high technology industries. The SMD Series are single-substrate sputtering systems for deposition of films such as metal films and TCO (Transparent Conductive Oxide) films. ULVAC has delivered a large number of these systems not only Organic Evaporating systems but also LTPS CVD systems. The most important technology of thin-film encapsulation (TFE) is preventing moisture($H_2O$) and oxygen permeation into flexible OLED devices. As a polymer substrate does not offer the same barrier performance as glass substrate, the TFE should be developed on both the bottom and top side of the device layers for sufficient lifetimes. This report provides a review of promising thin-film barrier technologies as well as the WVTR(Water Vapor Transmission Rate) properties. Multilayer thin-film deposition technology of organic and inorganic layer is very effective method for increasing barrier performance of OLED device. Gases and water in the organic evaporating system is having a strong influence as impurities to OLED device. CRYO pump is one of the very useful vacuum components to reduce above impurities. There for CRYO pump is faster than conventional TMP exhaust velocity of gases and water. So, we suggest new method to make a good vacuum condition which is CRYO Trap addition on OLED evaporator. Alignment accuracy is one of the key technologies to perform high resolution OLED device. In order to reduce vibration characteristic of CRYO pump, ULVAC has developed low vibration CRYO pumps to achieve high resolution alignment performance between Metal mask and substrate. This report also includes ULVAC's approach for these issues.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.134-134
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• 2012

We investigated the interface of poly (3-hexylthiophene) (P3HT) and C61-butyric acid methylester (PCBM) by using photoelectron spectroscopy (PES). These are the most widely used materials for bulk heterojunction (BHJ) organic solar cells due to their high efficiency. Study of the BHJ interfaces is difficult because the organic films are typically prepared by spin coating in ambient conditions. This is incompatible with the interface electronic structure probes such as PES, which requires ultrahigh vacuum conditions. Study of interface requires gradual deposition of thin films that is also incompatible with the spin coating process. In this work, we used electrospray vacuum deposition (EVD) technique to deposit P3HT and PCBM in high vacuum conditions. EVD allows us to form polymer thin films onto ITO substrate in a step-wise manner directly from solutions and to use PES without exposing the sample to the ambient condition. Although the morphology of the EVD deposited P3HT films observed by optical and atomic force microscopes is quite different from that of the spin coated ones, the valence region spectra were similar. PCBM was deposited on the P3HT film in a similar manner and the energy level alignment between these two materials was studied. We discuss the relation between Voc of P3HT:PCBM solar cell and HOMO-LUMO energy offset obtained in this study.

• 한국광학회지
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• 제17권3호
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• pp.285-289
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• 2006

광섬유형 콜리메이터와 광 진행 경로의 수직 방향으로 삽입된 주기적으로 식각된 줄무늬(stripe) 평판에 의해 진행하는 빔의 일부에 광 경로차를 유도하는 마이크로 옵틱형 마하젠더 간섭형 필터를 제안하고 구현하였다. 제안된 마이크로 옵틱 필터는 주기적으로 식각된 줄무늬(stripe) 구조의 평판을 빔 경로에 삽입하여 측방향 정렬에 무관하게 특정 소멸비 값 이상의 특성을 구현할 수 있으며, 식각된 박막의 두께를 조정함으로써 원하는 대역폭 및 주기의 전달특성을 가지는 필터를 구현할 수 있다. 네거티브 포토레지스터인 SU-8을 기반으로 줄무늬(stripe) 구조의 주기적으로 식각된 평판을 제작하였으며 이를 이용하여 구현된 필터의 소멸비는 측방향 정렬에 무관하게 30 dB이상의 값을 가진다. 제작된 필터의 FSR(Free Spectral Range)은 장파장 대역에서 약 237 nm이고 그리고 삽입손실은 2 dB 미만의 값을 가진다. 통과대역에서의 PDL(Polarisation Dependent Loss)값은 0.15 dB 미만이다.

• 한국광학회지
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• 제3권2호
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• pp.77-85
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• 1992

Varied-line spacing concave grating을 이용하여 결상면에서 거의 균일한 분해능을 갖는 평면결상 극자외선 분광기를 설계하엿다. 레이저-프라즈마에서 복사되는 발산광의 집속과 분광기의 수차보정을 위해 toroidal mirror를 사용하였고, 비축광선에 의한 수차를 줄이기 위해 toroidal mirror와 회절격자 사이에 10$\mu \textrm m \times2$mm크기의 입사슬릿을 두었다. 평면결상이 가능한 파장영역은 50~300$\AA$이고, 계산된 분해능은 4000이상이다. 회절격자의 효율과 toroidal mirror에서의 반사율을 고려하면 복사 에너지의 집속도는 toroidal mirror를 사용하지 않았을 때보다 3.5배 증가하고, fluorescence는 파장 100.angs.에서 1000배 이상 증가했다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.252.2-252.2
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• 2013

ZnO nanostructures have a lot of interest for decades due to its varied applications such as light-emitting devices, power generators, solar cells, and sensing devices etc. To get the high performance of these devices, the factors of nanostructure geometry, spacing, and alignment are important. So, Patterning of vertically- aligned ZnO nanowires are currently attractive. However, many of ZnO nanowire or nanorod fabrication methods are needs high temperature, such vapor phase transport process, metal-organic chemical vapor deposition (MOCVD), metal-organic vapor phase epitaxy, thermal evaporation, pulse laser deposition and thermal chemical vapor deposition. While hydrothermal process has great advantages-low temperature (less than $100^{\circ}C$), simple steps, short time consuming, without catalyst, and relatively ease to control than as mentioned various methods. In this work, we investigate the dependence of ZnO nanowire alignment and morphology on si substrate using of nanosphere template with various precursor concentration and components via hydrothermal process. The brief experimental scheme is as follow. First synthesized ZnO seed solution was spun coated on to cleaned Si substrate, and then annealed $350^{\circ}C$ for 1h in the furnace. Second, 200nm sized close-packed nanospheres were formed on the seed layer-coated substrate by using of gas-liquid-solid interfacial self-assembly method and drying in vaccum desicator for about a day to enhance the adhesion between seed layer and nanospheres. After that, zinc oxide nanowires were synthesized using a low temperature hydrothermal method based on alkali solution. The specimens were immersed upside down in the autoclave bath to prevent some precipitates which formed and covered on the surface. The hydrothermal conditions such as growth temperature, growth time, solution concentration, and additives are variously performed to optimize the morphologies of nanowire. To characterize the crystal structure of seed layer and nanowires, morphology, and optical properties, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Raman spectroscopy, and photoluminescence (PL) studies were investigated.

• 한국광학회지
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• 제19권4호
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• pp.276-286
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• 2008

스테레오 카메라를 사용하여 입체영상을 획득하는 대표적인 방법으로는 수렴 및 평행방식이 있다. 본 연구는 수렴 및 평행타입의 장점을 갖추고 자연스런 입체영상을 획득할 수 있는 평행타입 기반의 변형평행타입 입체영상 획득 방법을 사용하여 수렴방식의 입체영상 획득방법을 모사할 수 있는 인자들의 추출 및 정량적 분석을 통하여 중요 핵심인자를 정의하였다. 결과적으로 변형평행 타입에서 수렴타입을 모사할 수 있는 인자들은 스테레오 카메라의 간격, 화각 및 수렴각이고, 융합영역 내에서의 핵심인자는 수렴각의 변화이다. 결론적으로 변형평행타입으로 수렴타입을 완벽히 모사할 수 있는 인자들의 정량적 범위는 사용환경에 따라 다르며, 초점길이가 짧을 수록, 수렴각이 작을수록 근거리 물체에 대한 수렴타입과 변형평행타입의 영상좌표의 오차량은 적다.