• Transactions on Electrical and Electronic Materials
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• 제10권4호
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• pp.107-110
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• 2009

In this study, the Hall effect has been studied in n-GaAs samples characterized by V/IIl growth ratios of 25, 50 and 100 and prepared by metal organic chemical vapor deposition. For the Hall effect measurements, the grown samples were cut to a size of 1${\times}$1 cm. The measurements were carried out at room temperature, using Indium contact metal at the four corners of the samples. According to the experimental results, the Schottky effect was not ovservation. Also for the n-GaAs sample of V/Ill 100 ratio the electron drift velocity was very high.

• Rapid Communication in Photoscience
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• 제1권1호
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• pp.11-12
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• 2012

The naphthalic amide derivatives were synthesized by simple condensation and were crystallized by acetonitrile solution. The SEM images of products with methyl group and nitro group, respectively, showed rod shape while the SEM images of products with other groups ($N(CH_3)_2$, $OCH_3$, H, F, and Cl), respectively, showed plate shape. We were known from these results that the substituent of ending group played an important role in the crystallization of single molecule and the morphology of naphthalic derivatives could be controlled by only change of ending group in single molecule.

• Rapid Communication in Photoscience
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• 제3권4호
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• pp.64-66
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• 2014

Synthesis of a deuterium-labeled derivative of nitrospirobenzopyran (NSP), one of representative photochromic compounds, has been described. Four deuteriums were successfully introduced on 1-methyl and ${\alpha}$-methyne relative to spiro-carbon in the title compound with more than 95atom%D purity. Main photodegraded products of NSP were two oxindoles in acetonitrile, and additional products were formed in poly(isobutyl-methacrylate) films possibly due to restricted molecular motion in polymer matrix. Quantitative HPLC analysis revealed that partial introduction of deuterium to NSP brought a noticeable isotope effect, recognizable enhancement in photo-resistivity of NSP, i.e.,8.3% in solutions and 29% in polymeric films.

• 한국인쇄학회:학술대회논문집
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• 한국인쇄학회 2001년도 국제학술발표회
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• pp.45-45
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• 2001

자료의 보존에 있어서 종이의 열화로 인해 자료의 분석, 열화메커니즘의 해석, 종이의 보존이란 측면 하에서의 관심이 서서히 집중되고 있는 실정이며, 그 중요성도 크게 대두되고 있는 실정이다. 산성지를 중성화하는 화학적시스템, 즉, 탈산성화처리는 알카리계금속(Ca, Mg, Zn, Na)과 유기용매, 수용성용매를 이용하여 이들 약품을 종이내에 침투시켜 중성화(pH 6-8) 함으로써 종이의 주성분인 cellulose를 보다 안정화시키는 방법으로 산을 중화하여 보존성을 향상시킬 수 있는 것이다. 즉, 탈산처리란 화학적으로 종이속에 생기는 산 또는 산을 발생하는 물질을 알칼리물질로 중화하는 것이다. 또한 중화후 알칼리 물질이 종이에 잔류하면 장래에 내부적으로 발생하는 산이나 외부(대기중의 오염물질 등) 로부터 침입하는 산도 중화하여 보존성을 향상시킬 수가 있다. 따라서, 본 연구는 산성초지법에 의해 제조된 용지들의 열화특성과 알카리 토금속을 처리한 후에 알카리도를 상승시킨 용지의 열화특성을 물리·화학적 변화를 통하여 종이의 보존성을 비교 검토·규명함으로써 문(도)서의 보존체계를 마련하고자 하며, 보존과 관련된 기초자료를 얻고자 실시하였다.

• 한국전기전자재료학회논문지
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• 제15권3호
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• pp.275-280
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• 2002

The peculiarities of using Self-propagating High-temperature Synthesis (SHS) and solid-stave chase synthesis for production of high temperature superconductor materials were discussed. Oxide superconductors with general formula of $ReBa_2Cu_3O_{7-x}$ (Re=Y, Sm) haute been made by using barium oxide initial powder instead of traditional barium carbonate. Phenomena observed during the grinding of the reactants mixture are presented. Mechano-chemical activation - as a pre-treatment of the reactants mixture - strongly influences the kinetic parameters, the reaction mechanism, and the composition and structure of the final product.

• Journal of information and communication convergence engineering
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• 제16권1호
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• pp.48-51
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• 2018

The traditional documents analysis was centered on words based system was implemented using a morpheme analyzer. These traditional systems can classify used words in the document but, cannot help to user's document understanding or analysis. In this problem solved, System needs extract for most valuable paragraphs what can help to user understanding documents. In this paper, we propose system extracts paragraphs of normalized XML document. User insert to system what filename when wants for analyze XML document. Then, system is search for keyword of the document. And system shows results searched keyword. When user choice and inserts keyword for user wants then, extracting for paragraph including keyword. After extracting paragraph, system operating maintenance paragraph sequence and check duplication. If exist duplication then, system deletes paragraph of duplication. And system informs result to user what counting each keyword frequency and weight to user, sorted paragraphs.

• Rapid Communication in Photoscience
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• 제4권2호
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• pp.29-30
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• 2015

Since the first report on long-term durable perovskite solar cell in 2012, a surge of interest in perovskite solar cell has been received due to its superb photovoltaic performance exceeding 20%. $MAPbI_3$ ($MA=CH_3NH_3$) perovskite film is able to be prepared simply by solution processesof either sequential two-step or single step procedure. Since $MAPbI_3$ shows balanced charge transport property with micrometer scale charge diffusion length, it can be applied to any kind of junction structures. Mostly studied structure is mesoscopic structure employing mesoporous oxide layer in perovskite film. Photovoltaic performance is primarilyin fluenced by the quality of perovskite film but interfaces are equally important. In this mini review, emergence and evolution of perovskite solar cell are described.

• 한국광학회지
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• 제5권2호
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• pp.340-346
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• 1994

2.5Gbps 광통신시스템용 수광소자로서 charge plate층을 갖는 링구조의 separate absorption grading multiplication avalanche photodiode를 제작하고 그 특성을 조사 분석하였다. Avalanche Photodiode의 제작은 Metal-Organic Chemical Vapor Deposition 과 Liquid Phase Epitaxy법을 이용한 에피성장과 Br:Methanol을 이용한 채널식각 방법을 사용하였고, passivation과 평탄화는 photosensitive polyimide를 이용하였다. 제작된 ADP는 10nA 이하의 작은 누설전류를 나타내었고, -38~39 V의 항복전압을 나타내었다. 제작된 ADP를 GaAs FET hybrid 전치증폭기와 결합하여 2.5Gbps 속도에서 $2^{23}-1$의 길이를 갖는 입력 광신호에 대해 $ 10^{-10}$ Bit Error Rate에서 -31.0dBm의 수신감도를 얻었다.

• Rapid Communication in Photoscience
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• 제5권1호
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• pp.8-10
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• 2016

The potential curves of OH bonds of liquid water are inhomogeneous because of a variety of interactions with other molecules and this leads to a wide distribution of vibrational frequency which hampers our understanding of the structure and dynamics of water molecules. Mixed quantum/classical (QM/CM) calculation methods are powerful theoretical techniques to help us analyze experimental data of various vibrational spectroscopies to study such inhomogeneous systems. In a type of those approaches, the interaction energy between OH bonds and other molecules is approximately represented by the interaction between the charges located at the appropriate interaction sites of water molecules. For this purpose, we re-calculated the values of charges by comparing the approximate interaction energies with quantum chemical interaction energies. We determined a set of charges at the TIP4P charge sites which better represents the quantum mechanical potential curve of OH bonds of liquid water.

• Rapid Communication in Photoscience
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• 제2권1호
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• pp.24-27
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• 2013

A polymeric photobase generator containing oxime-urethane groups is applied to a fluorescence micropatterning material. Polymer bearing oxime-urethane groups was prepared by copolymerization of methyl methacrylate with methacryloyloxyethyl benzophenoneoxime urethane (MBU). The reaction of amino groups in the irradiated copolymer film with dansyl chloride (Dns-Cl) was monitored by using UV absorption, IR absorption and fluorescence spectroscopy. The fluorescence spectrum of the Dns-Cl-treated irradiated copolymer film shows a strong fluorescence with a fluorescence maximum wavelength at 510 nm. A blue fluorescent micropattern with a line width of $2{\sim}3{\mu}m$ was obtained. Treatment of the irradiated copolymer film with Dns-Cl and rhodamine B mixture led to the formation of green, red, and orange-colored fluorescence micropatterns. Thus, various colored micropatterns on a single polymer film can be obtained by selective excitation of each dye molecules.