• 한국세라믹학회지
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• 제52권3호
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• pp.221-223
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• 2015

In this work, we report on the preparation of the anodically-grown $TiO_2$ nanotube arrays sensitized with $In_2S_3$ nanoparticles by using the SILAR (successive ionic layer adsorption and reaction) process. We evaluate the photo-catalytic properties of the prepared hetero-structures under visible-light illumination. The results reveal that the $TiO_2/In_2S_3$ system has enhanced photo-catalytic characteristics including higher chopping height. Improved performance of the heterojunction is attributed to the narrower band gap of $In_2S_3$ and its favorable position within the conduction band relative to that of $TiO_2$.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.217-217
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• 2012

Solution-processed tungsten oxide thin film with thickness of about 30 nm is prepared from ammonium tungstate. This layer is introduced into the interface between the poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) layer and the ITO electrode to be used as an electron blocking layer. The annealed tungsten oxide thin films at $150^{\circ}C$ and $300^{\circ}C$ show amorphous phase, while the $400^{\circ}C$ -annealed tungsten oxide film shows crystalline phase. At $150^{\circ}C$ annealing temperature, the conversion efficiency is significantly improved from 0.71% to 1.42% as the condition is changed from vacuum to air atmosphere, which is related to oxidation state of tungsten in amorphous phase. For the air annealing condition, the conversion efficiency is further increased from 1.42% to 2.01% as the temperature is increased from $150^{\circ}C$ to $300^{\circ}C$, which is mainly due to the removal of the chemisorbed water. However, a slight deterioration in photovoltaic performance is observed when the temperature is increased to $400^{\circ}C$, which is ascribed to poor electron blocking ability due to the formation of crystalline phase. It is concluded that $W^{6+}$ oxidation state and amorphous nature in tungsten oxide interlayer is essential for blocking electron effectively from the active layer to the ITO electrode.

• 대한본초학회지
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• 제22권1호
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• pp.71-79
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• 2007

Objectives : This study was designed to establish a characteristic discrimination of internal and external morphological standard of original plants and herbal states in Polygoni Multiflori and Cynanchi Wilfordii Radix. Methods : In this studies, the external-internal morphological standards were determined by using stereoscope and butanol series. Results: 1. The external characteristics of original plants: Polygonum Multiflorum has alternate leaves, and its flower with white color blooms at the shoot apex or leaf axil. In the other hand, Cynanchum wilfordii has opposite leaves, and its flower with yellowish green color blooms at the leaf axil. 2. The physical characteristics of herbal slates: Polygoni Multiflori Radix is red-brown in outer surface pink-brown in section. In the other hand, Cynanchi Wilfordii Radix is earthly-brown in outer surface greyish white in section. 3. The physical characteristics according to the place of production: Demonstrable difference according to the place of production is not seen. Polygoni Multiflori Radix is brown or dark brown in outer surface, soft $Yellow{\sim}dark$ brown in section. In the other hand, Cynanchi Wilfordii Radix is white in outer surface, $white{\sim}weak$ red in section, and has power type. 4. The internal characteristics: Polygonum multiflorum has hetero-vascular bundle and lignification of cork layer is progressive. In the other hand, Cynanchum wilfordii has not hetero-vascular bundle, and lignification of cork layer is weak. Conclusion: In the future, many fundamental study such as how to discriminate between Polygoni Multiflori Radix and Cynanchi Wilfordii Radix in origin and efficacy will be necessary. Also the standard of discrimination must be specific and distinct in that several kinds of fo-ti has been traded. It is considered the results of this study will be furnish κ I the basis Lo succeeding studies and it is needed to extensive comparative study for the same genus-degree of relatedness.

• 한국결정성장학회지
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• 제31권6호
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• pp.233-239
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• 2021

본 연구에서는 산화갈륨의 방열 특성 향상을 위해 산화갈륨/다이아몬드 이종 박막 성장을 진행하였다. 먼저, 핫필라멘트 화학기상증착법을 이용하여 다결정 다이아몬드를 증착시킨 후, 미스트 화학기상증착법을 통해 450~600℃ 사이의 온도구간에서 산화갈륨 박막을 성장시켰다. 열처리 전후 비교를 통해 500℃에서 산화갈륨/다이아몬드 계면 분리 현상이 발생함을 확인하였다. 이는 비정질과 결정질이 혼재된 산화갈륨 박막이 성장된 후, 냉각 과정에서 열팽창계수의 차이로 인해 계면이 분리된 것으로 판단하였다. 따라서, 본 연구를 통한 산화갈륨/다이아몬드 계면의 물리적 안정성을 통해 산화갈륨의 열물성 보완및 고전력 반도체로의 활용이 기대된다.

• 한국잠사곤충학회지
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• 제21권2호
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• pp.1-6
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• 1979

잠체의 몇가지 양적형질에 관여하는 유전자의 우성정도, 유전력, 유전자의 분포상태등을 알기 위하여 누에의 6개 품종을 교배친으로 하여 이면교잡을 한 F$_1$세대와 교배친품종을 재료로 유전분석을 한바 그 결과를 요약하면 다음과 같다. 1. 각 형질의 측정치는 품종과 조합에 따라서 다르고 특히 전견양과 견층양은 자잠이 웅잠보다 많고, 견층비율은 자잠보다 웅잠이 크게 나타났다. 2. 각 형질별 분산성분중 상가적효과에 의한 분산D보다 Herterosis등에 의한 분산 H가 크며 우성정도가 모두 1이상으로 나타났으므로 품종 자체가 hetero상태라는 것을 알 수 있었다. 3. 광의의 유전력은 모두 높았으나 협의의 유전력이 비교적 높은 형질은 전령경과일수, 5영경과일수, 견층비율의 3개형질이었다. 4. 유전자의 분포상태를 보면 전령경과일수, 5영경과일수, 견층비율의 3개형질은 불완전우성으로, 전견양과 견층양의 2개형질은 초우성으로 나타났다. 5. 전령경과일수와 5영경과일수에 관여하는 유전자는 B(112)품종에 우성유변자가 많고, A(111)품종이나 E(경추)품종에 열성 유전자가 많이 관여하고 있는 것으로 보인다. 견층비율에는 자웅에 따라서, 품종에 따라서 우성 또는 열성유전자가 관여하는 정도가 다르며 전견양과 견층양의 2개형질은 초우성으로 나타나고, F(연일) 품종과 E(경추) 품종에 우성유전자가 많이 관여하고 B(112)품종과 A(111)품종에 열성유전자가 많이 관여하고 있는 것으로 보인다. 이상의 결과를 미루어 보아 전견양과 견층양을 증가시키기 위한 교배친으로서는 F(연일) 품종이 제일 좋고 다음으로 E(경추)품종이 유리할 것으로 사료된다.

• ETRI Journal
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• 제27권5호
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• pp.569-578
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• 2005

The purpose of this paper is to describe the implementation of monolithically matching circuits, interface circuits, and RF core circuits to the same substrate. We designed and fabricated on-chip 1 to 6 GHz up-conversion and 1 to 8 GHz down-conversion mixers using a 0.8 mm SiGe hetero-junction bipolar transistor (HBT) process technology. To fabricate a SiGe HBT, we used a reduced pressure chemical vapor deposition (RPCVD) system to grow a base epitaxial layer, and we adopted local oxidation of silicon (LOCOS) isolation to separate the device terminals. An up-conversion mixer was implemented on-chip using an intermediate frequency (IF) matching circuit, local oscillator (LO)/radio frequency (RF) wideband matching circuits, LO/IF input balun circuits, and an RF output balun circuit. The measured results of the fabricated up-conversion mixer show a positive power conversion gain from 1 to 6 GHz and a bandwidth of about 4.5 GHz. Also, the down-conversion mixer was implemented on-chip using LO/RF wideband matching circuits, LO/RF input balun circuits, and an IF output balun circuit. The measured results of the fabricated down-conversion mixer show a positive power conversion gain from 1 to 8 GHz and a bandwidth of about 4.5 GHz.

• 한국정보통신학회논문지
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• 제7권4호
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• pp.750-757
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• 2003

현재 XML응용 분야 가운데 XML 표준 데이터를 이용하여 정보의 교환 및 변환을 하여 시스템의 이식성과 확장성을 증대시키고자 하는 연구가 활발하게 이루어지고 있다. 본 논문은 클라이언트와 서버사이에서 비호환성과 확장에 따른 개발비용 문제를 해결하기 위해 클라이언트와 서버사이에 XML 중간계층을 이용한 시스템 설계를 제시한다. 이 방법은 클라이언트와 서버사이의 프로그램 개발시 중간 조정 역할을 하며, 이질적인 환경에서의 이식성과 시스템의 확장성을 증대시킨다. 본 논문은 XML 기반 DB를 이용하여 전자상거래를 위한 XML 데이터 처리 시스템을 설계 및 구현하였다. 기대효과로는 XML 기반의 전자상거래 구조를 활용함으로서 시스템 확장성과 시스템의 유지보수를 위한 비용절감이 기대된다.

• 센서학회지
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• 제24권4호
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• pp.219-223
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• 2015

Indium free consisting of three alternating layers GTO/Ag/GTO has been fabricated by radio-frequency (RF) sputtering for the applications as transparent conducting electrodes and the structural, electrical and optical properties of the gallium tin oxide (GTO) films were carefully studied. The gallium tin oxide thin films deposited at room temperature are found to have an amorphous structure. Hall Effect measurements show a strong influence on the conductivity type where it changed from n-type to p-type at $700^{\circ}C$. GTO/Ag/GTO multilayer structured electrode with a few nm of Ag layer embedded is fabricated and show the optical transmittance of 86.48% in the visible range (${\lambda}$ = 380~770 nm) and quite low electrical resistivity of ${\sim}10^{-5}{\Omega}cm$. The resultant power conversion efficiency of 2.60% of the multilayer based OPV (GAG) is lower than that of the reference commercial ITO. GTO/Ag/GTO multilayer is a promising transparent conducting electrode material due to its low resistivity, high transmittance, low temperature deposition and low cost components.

• 전자공학회논문지A
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• 제31A권9호
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• pp.104-113
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• 1994

We have fabricated n-p-n HBTs using 3-inchAlgaAs/GaAs hetero structure epi-wafers grown by MBE. DC and AC characteristics of HBT devices were measured and analyzed. For HBT epi-structure, Al composition of emitter was graded in the region between emitter cap and emitter. And base layer was designed with concentration of 1${\times}10^{19}/cm^{3}$ and thickness of 50nm, and Be was used as the p-type dopant. Principal processes for device fabrication consist of photolithography using i-line stepper, wet mesa etching, and lift-off of each ohmic metal. The PECVD SiN film was used as the inslator for the metal interconnection. HBT device with emitter size of 3${\times}10{\mu}m^{2}$ resulted in cut-off frequency of 35GHz, maximum oscillation frequency of 21GHz, and current gain of 60. The distribution of the ideality factor of collector and base current was very uniform, and the average values of off-set voltage and current was very uniform, and the average values of off-set voltage and current gain were 0.32V and 32 within a 3-inch wafer.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.481.2-481.2
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• 2014

Bulk hetero junction (BHJ) polymer solar cell (PSCs) is one of the most promising fields as alternative energy source. Especially, the development of new p-type conjugated polymer is one of the main issues to get core technology. In this study, we investigated the chemical doping effects of incorporating 3,6-carbazole units into conjugated polymers based on 2,7-carbazole. We assessed the structural effects of this chemical doping by measuring the photovoltaic device performance of the copolymers with and without annealing. Note that the use of nanostructures in the bulk heterojunction layer could be a major obstacle to commercialization because nano-morphologies are frequently unstable at high temperatures. Therefore, the development of thermally stable polymer:fullerene blends with optimized PCEs is an important goal in this area of research. We studied the morphologies of the copolymers incorporating 3,6-carbazole units resulting from thermal annealing to investigate the effects of the difference between the T g values of the 2,7-carbazole unit and the 3,6-carbazole unit.