• 제목/요약/키워드: UV-absorption

검색결과 1,096건 처리시간 0.032초

Morphology-Controlled Fabrication of ZnS Nanostructures with Enhanced UV Emission

  • 김연호;장두전
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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    • pp.587-587
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    • 2013
  • ZnS is well-known direct band gap II-VI semiconductor, and it attracts intense interest due to its excellent properties of luminescence which enable ZnS to have promising materials for optical, photonic and electronic devices. Especially, the emission wavelength of ZnS falls in the UV absorption band of most organic compoundsand biomolecules, thus it is envisaged that ZnS based devices may find applications in increasingly important fluorescence sensing. We have developed a facile and effective one-step process for the fabrication of single-crystalline and pure-wurtzite ZnS nanostructures possessing sharp band-edge emission at room-temperature having diverse length-to-width ratios. Each of nanostructures was composed of chemically pure, structurally uniform, single-crystalline, and defect-free ZnS. These features not only suppress trap or surface states emission centered at 420 nm, but also enhance UV band-edge emission centered at 327 nm, which give as-synthesized our ZnS nanostructures possible sharp UV emission at room temperature. The reaction medium consisting of mixed solvents such as hydrazine, ethylenediamine, and water as well as proper reaction time and temperature have played an important role in the crystallinity and optical properties of ZnS nanostructures. As-synthesized our ZnS nanostructures possessing sharp UV emission guarantee high potential for both fundamental research and technological applications.

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MWCNT와 여러가지 티탄알콕사이드 전구체를 사용하여 CNT/TiO2 복합체의 제조와 광촉매분해 (Preparation and photocatalytic degradation of CNT/TiO2 composites using MWCNT and various titanium alkoxide precursors)

  • 진명량;장봉군;오원춘
    • 분석과학
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    • 제21권6호
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    • pp.553-561
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    • 2008
  • MWCNT 와 여러 가지 티탄 알콕사이드 전구체를 사용하여 $CNT/TiO_2$ 복합제를 제조하였다. 이들 복합체들은 SEM, FE-SEM, XRD, EDX 및 UV-vis 분광기를 사용하여 종합적으로 분석하였다. UV 조사하에서 MB모델 수용액의 변이에 대한결과로부터 제조된 물질에 대한 광활성을 시험하였다. 마지막으로 MB 제거 실험의 결과에 따르면, 시료 CTOS의 경우 시료 CTIP 및 CTPP의 경우보다 우수한 MB제거 효과를 나타내었다.

박테리오파지 f2에 대한 자외광선의 살균효과 (The Inactivation Effects of UV Light on Bacteriophage f2)

  • Kim, Chi-Kyung;Quae Chae
    • 한국미생물·생명공학회지
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    • 제11권3호
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    • pp.155-161
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    • 1983
  • Bacteriophage f2에 대한 자외광선의 살균효과와 외투막 단백질의 구조에 미치는 영향을 Ray-onet photoreactor PPR-208을 사용하여 300nm의 광선으로 연구하였다. 처음 20분간의 조사에서는 약 4 log의 phage가 감소되고 그후 완만한 살균효과를 보이다가 90분 이상의 조사에서는 생존 바이러스가 발견되지 않았다. Tryptophan residue의 fluorescenve quenching, 자외선으로 조신한 phage에 부착시킨 ANS (8-anilino-1-napht-halene sulfonate)의 fluorescence emission의 감소, tryptophan에서 ANS로의 energy transfer 의 감소 등 spectroscopic technique에 의한 결과와 자외선 조사에 의하여 단백질 외투만이 파손되는 전자현미경 관찰의 결과에 의하여 자외광선은 phage f2의 외투막 단백질의 구조에 변화를 일으킨다는 것이 밝혀졌다.

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UV-Vis와 ED-XRF를 이용한 자연 색상의 담수 흑 양식진주 분석 (UV-Vis and ED-XRF Analyses of Natural Black Colored Pearls from Freshwater Cultured Shells)

  • 김혜연;박종완
    • 한국패류학회지
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    • 제24권3호
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    • pp.243-251
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    • 2008
  • 진주의 감별기법상 UV-Vis의 흡수 스펙트럼 분석과 반사율 분석은 흑진주의 색깔이 자연 그대로인지 아니면 처리에 의한 결과인지를 구별하는데 중요한 요소가 된다. 또한 ED-XRF을 이용한 미량 원소 분석은 진주가 해수산인지 담수산인지 여부와 은염 또는 염색 처리 유무를 판단하는데 이용될 수 있다. 본 연구에서는 은염 또는 염색 처리되지 않은 여러 종류(담수양식진주, 아코야양식진주, 타히티흑양식진주)의 진주에 은염처리를 한 결과, 은 이온 고유의 스펙트럼이 진주 고유의 스펙트럼에 영향을 주어 UV-Vis흡수 스펙트럼이 변화되었다. 또한 반사율도 은염처리하기 전보다 낮아짐을 알 수 있었다. 특히 자연 색상의 타히티흑양식진주의 경우 400 nm, 500nm, 700 nm의 고유 흡수 스펙트럼을 갖고 있었으며, 자연색상의 담수흑양식진주의 경우 380-400 nm, 480-500 nm 두 개의 특징적인 흡수 스펙트럼으로 나타났다. 자연 색상의 담수흑진주에서는 자연 색상의 타히티흑진주와는 달리 700nm의 흡수 스펙트럼이 관찰되지 않았다. 직접 은염처리한 진주 9 개를 ED-XRF를 이용하여 분석한 결과, 처리시간이 증가함에 따라 진주 층에 침투된 은의 함량이 점차로 증가했음을 알 수 있었다. 또한 시중에서 구입한 흑진주 18 개를 분석한 결과, 은 이온의 상대 함유량이 약 0.1%를 경계로 은염 또는 염색 처리 여부를 판단하는 데 도움을 줄 수 있을 것으로 생각되었다.

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Preparation of the Polymers Containing Phenylamide and Dimethylaminoethyl Groups and their Properties as a Nagative Photoresist

  • Chae, Kyu-Ho;Kang, Jin-Koo;Kim, Su-Kyung;Chough, Sung-Hyo
    • Journal of Photoscience
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    • 제7권2호
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    • pp.47-52
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    • 2000
  • The copolymmers of N, N-dimethylaminoethyl methacrylate(DAEM) and N-arylmethacrylamide (AMA) were prepared, and their photochemical properties as a negative photoresist were studied by the measurements of insoluble fraction, and by UV and IR absorption spectral changes. These copolymers are soluble in DMF, actone, methanol, of acidic buffer solutions. Solubility of these copolymer films in the vuffer solutions increased with the amount of DAEM units in the copolymer and decreased with the pH value. The insoluble fraction of the copolymer films in the buffer solution of pH 4 of in methanol increased with irradiation time and the amount of AMA units in the copolymer. UV and IR spectral changes indicated that not only photo-crosslinking but also the photo-Fries rearrangement took place upon irradiation with a 254nm UV light.

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시멘트 복합체 내에서 UV처리에 따른 PVA 및 PET섬유의 계면 및 매입인발특성 (Interfacial and Pull-out Properties of PVA and PET Fiber with UV Irradiation in Cementitious Composites)

  • 전에스더;이상수;윤현도
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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    • pp.401-404
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    • 2006
  • Much of requirements to the civil and building structures have been changed in accordance with the social and economic progress. Ductility of high performance fiber reinforced cementitious composites(HPFRCCs), which exhibit strain hardening and multiple crackling characteristics under the uniaxial tensile stress is drastically improved. In HPFRCC application, PVA fiber has been dominantly used as a reinforcement because of its excellent alkali resistant nature as well as high strength. But the inherent strong hydrophilicity of PVA fiber promotes the moisture absorption in cement matrix and thus it may cause the corrosion of steel structure. Therefore, it is necessary to control the interfacial adhesion of cement composites. In present study, to control the interfacial adhesion of the cementitious composites reinforced by PVA fiber, UV irradiation of the PVA fiber were performed and their effects on the adhesion property and general characteristics were investigated extensively.

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ULTRAVIOLET AND VISIBLE SPECTROSCOPIC DATABASE FOR ATOMS AND MOLECULES IN CELESTIAL OBJETS

  • Kim, Sang-J.
    • 천문학논총
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    • 제9권1호
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    • pp.111-166
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    • 1994
  • I have developed a UV and visible spectroscopic database (UVSD) for atoms and molecules, which are found in interstellar medium, stars, galaxies, and in the atmospheres of the earth, planets, satellites, and comets. This UV and visible database, which is machine-readable, consists of three different sub-databases depending upon the characteristics of the sub-databases: (A) atomic and molecular line listings from laboratory observations or theoretical studies; (B) absorption spectra measured in laboratories; and (C) solar UV, visible, and infrared spectral atlases. The UVSD is in a very initial stage of development compared with other well organized and established infrared and microwave databases. In order to make a good quality and complete database, substantial efforts should be made for the acquisition of scattered important data from laboratories or institutions, and then the acquired heterogeneous data should be peer-reviewed and standardized.

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광섬유 대기오존 모니터 (Optical Fiber Atmospheric Ozone Monitor)

  • 정완영
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2002년도 하계종합학술대회 논문집(5)
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    • pp.201-204
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    • 2002
  • A high accuracy ozone monitor using UV absorption method was developed for ambient ozone monitoring. The system was mainly composed of a high power pulsed xenon lamp as UV source, an optical spectrometer with a high sensitivity linear CCD array as UV detector and signal processing unit. The optical signal from the CCD array that provides unusually high response and excellent optical resolution for ozone concentration was converted to digital signal and the digital signal was displayed on screen using PC interface. The optical signal was propagated using optic fiber to reduce optical loss to increase the accuracy of the measuring system. This paper has been studied a interworking signalling protocol between two hybrid networks by analyzing Satellite B-ISDN architecture, DSS2 Layer 3 Signalling protocol, B-ISUP protocol, S-BISUP protocol stack and so on. Also in the paper, messages and primitives have been defined for B-ISDN's Connection Type, Ownership and each protocol in order to connect point-to-multipoint. The ozone sensing properties of the CCD ozone monitor was compared with those of the photo multiplier ozone monitor.

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$TiO_2$ 나노합성물에서 Dye의 광열화 특성 (Photodegration Properties of Dye in $TiO_2$ Nanocomposite)

  • 정재훈;조종래;문정오;양종현;문병기;손세모;정수태
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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    • pp.517-520
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    • 2001
  • The optical properties of $TiO_2$ thin films dispersed in epoxy film, which were prepared with bis-(4, 4'-P-toluenesulfonylacidic isoproplyidene) cycolhexadiol(BTSPC) and UVI 6990 in dry sol-gel process, were investigated. In the case of irradiating UV light on $TiO_2$ thin films, how many nanopartlcles of $TiO_2$ are dispersed in epoxy film was investigated by AFM. The absorption peak of the films was showed at 360nm. Squarylium dye was dispersed in $TiO_2$-epoxy film. Photodegration concerned with amount of dye and time of UV light irradiation was investigated. UV light irradiation on the film occurred dramatical photodegration.

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장쇄지방산의 길이에 따른 단분자막의 특성 변화 (A length dependance of monolayer films of long-chain fatty acids)

  • 구창권;김무군;송경호;박태곤
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1996년도 춘계학술대회 논문집
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    • pp.38-42
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    • 1996
  • The pressure-area isotherm of monolayer at the air-water interface were obtained and the LB films were fabricated onto a quartz slides and quartz crystal by conventional Langmuir-Blodggett(LB) method. The UV absorption spectra of Langmuir-Blodggett(LB) film on quartz slides and spectrum of monolayer formed on quartz crystal have been measured. The photoisomerization of the long-chain fatty avid containing azobenzene were obtained by the application of UV and visible light. The reversibility of photoisomerization were more clear difference when the number of C$\_$n/ increased. At the pressure-area isotherms, the value of surface pressure increment were decreased when the number of C$\_$n/ increased, A surface pressure of 20mN/m was obtained as a proper one for a film deposition. The photoisomerization at LB films were also obtained by application of UV and visible light. So the LB film of long-chain fatty acid containing azobenzene has possibility to being applies to functional molecular devices such as photomemory and light switching.

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