• 제목/요약/키워드: absorption spectrum

검색결과 764건 처리시간 0.025초

Absorption Spectroscopy of Biological Specimens Near X-ray Absorption Edges of Constituent Elements

  • Ito, Atsushi;Shinohara, Kunio
    • Journal of Photoscience
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    • 제9권2호
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    • pp.460-462
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    • 2002
  • Absorption spectra of biological specimens in the soft X-ray region have been presented with special reference to the XANES (X-ray absorption Near Edge Structure) of constituent elements. Absorption spectrum in this wavelength region is characterized by the absorption edges from which elemental content could be derived. In addition, XANES has a characteristic profile for chemical environment around the element such as chemical bond. Using the specific absorption peak we can assign not only the chemical bond but also molecules having such a chemical bond. In the present paper, absorption spectrum of DNA was measured in the wavelength range from 1.5nm to 5nm. Spectrum of Chinese Hamster Ovary (CHO) cells was compared with the DNA spectrum. XANES were distinct at the K absorption edges of major elements, C, N and O. In the spectrum of the cells prominent peaks at the L absorption edge of minor element Ca were also detectable. XANES profiles in small local areas in a cell could also be measured in combination with X-ray microscopy. These give information about local chemical environment in a cell. XANES at the phosphorus K absorption edge in a human HeLa cell was successfully obtained corresponding to a sharp and intensive XANES peak of DNA.

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Size Dependent Absorption Spectrum of ZnO Nanocrystals

  • Chang Ho Jung;Wang Yongsheng;Suh Kwang-Jong;Son Chang-Sik
    • 한국재료학회지
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    • 제15권7호
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    • pp.431-434
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    • 2005
  • To investigate the dependences of the absorption spectrum and electronic structure properties on the ZnO nano-particle size, ZnO nanocrystals were synthesized by a sol-gel method. The absorption onset peak exhibits a systematic blue-shift with decreasing particle size due to the quantum confinement effect, as well as, with decreasing $Zn^{2+}$ concentration. The increase of particle size is mainly controlled by coarsening and aggregation step during the nucleation and growth of ZnO nano-particles. The onset absorption spectrum of ZnO colloids changes from 310 to 355 nm as $Zn^{2+}$ concentration increases from 0.01 to 0.1 mole. The average particle size as a function of aging- time can be determined from the absorption spectra. The freshly prepared nanocrystal size was about 2.8nm.

캐스팅법으로 제작한 Poly(3-hexylthiophene)의 흡수스펙트럼에 따른 형광 특성 (Characteristics of Electronic Absorption Spectrum and Photoluminescence in Cast-Poly(3-hexylthiophene) Films)

  • 김주승;구할본;조재철
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1998년도 추계학술대회 논문집
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    • pp.57-60
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    • 1998
  • Poly(3-hexylthiophene)(P3HT) was synthesized by use of FeCl$_3$ as a oxidizing agent at $25^{\circ}C$. The infrared spectrum of our polymer gave good evidence for the conjugation of 3-hexylthiophene monomer unit. P3HT contains the HT(head-to-tail) linkage larger than 64% based on NMR analysis. Electronic absorption and photoluminescence studies show that cast films of P3HT have three exciting state. Absorption spectrum was separated with three maximum peaks by Giese-French method and shifted to the shorter wavelength with increasing temperature. Separated absorption spectrum of P3HT is well adapted to PL peak appeared at longer wavelength. Low temperature PL spectrum is well separated at 669nm, 733nm and 812nm.

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THE ABSORPTION LINE SPECTRUM OF QSO 1225+317

  • HUANG KELIANG;YUAN QIRONG
    • 천문학회지
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    • 제29권spc1호
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    • pp.105-106
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    • 1996
  • In this paper, we present observations of absorption line spectrum of QSO 1225+317 with resolution of 18 km $sec^{-1}$. Four possible new heavy element line systems are identified. The properties of Lyman $\alpha$ forest lines are discussed.

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Spectral Distribution and Spectral Absorption of Suspended particulates in Waters of Sanya Bay

  • Yang, Dingtian;Cao, Wenxi
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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    • pp.495-498
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    • 2006
  • Optical profile and spectral absorption of suspended solids in waters of Sanya bay was measured on August 8-14, 2003. Optical profile was taken by using MicroPro optical profile. Apparent optical indexes, vertical diffuse attenuation coefficient ($K_d$) and water leaving radiance (Lw), were calculated. $K_d$ at the blue end of the spectrum was greater than that at the red end of the spectrum in waters near Sanya River mouth, however, in waters near open sea, $K_d$ at the blue end of the spectrum was smaller than that at the red end of the spectrum. Distribution of water leaving radiance was relatively higher in waters near Sanya River mouth, but relatively weaker in near open sea water. Spectral absorption of suspended particulates was also measured. Results showed that the spectral absorption of chlorophyll a was greater in waters near Sanya river mouth, but relatively weaker in waters near open sea, which indicated higher concentration of phytoplankton in waters near Sanya river mouth. Except for water at the 5th sampling station, the ratio of spectral absorption of chlorophyll a to total suspended particulates in surface waters was greater than that in bottom waters at all stations.

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Spectroscopic Studies on the Oxidation of Catechin in Aqueous Solution

  • Bark, Ki-Min;Yeom, Ji-Eun;Yang, Jeong-Im;Yang, Ik-Jun;Park, Chul-Ho;Park, Hyoung-Ryun
    • Bulletin of the Korean Chemical Society
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    • 제32권9호
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    • pp.3443-3447
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    • 2011
  • The spectroscopic behavior of catechin (5,7,3',4'-tetrahydroxyflavan-3-ol), has been studied in the presence and the absence of air using UV-vis absorption spectrophotometry and fluorescence spectroscopy. The UV-vis absorption spectrum of catechin shows a very sharp and strong absorption maximum peak at 275 nm in deaerated water. New absorption maximum peaks appeared in aerated water, as well as in basic aqueous solution, caused by the oxidation of catechin. The absorbances in the UV-vis absorption spectrum of catechin decreased when the solution was left in the dark for a long time. The fluorescence emission spectrum of catechin after a long time period differs markedly from that in freshly prepared solution; the fluorescence maxia shifted as time passes after adding catechin to the solutions. When the deaerated basic catechin solutions were left in the dark for a long time, their fluorescence quantum yields were found to be nearly zero. This suggests that the oxidized catechin molecules were seen to have slowly undergone successive chemical reactions in basic buffer solution.

Spectroscopic Evidence for Aggregation of Stilbene Derivatives in Solution

  • Aguiar, M.;Akcelrud, L.;Pinto, M.R.;Atvars, T.D.Z.;Karasz, F.E.;Saltiel, Jack
    • Journal of Photoscience
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    • 제10권1호
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    • pp.149-155
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    • 2003
  • The absorption, fluorescence and fluorescence-excitation spectra of concentrated toluene solutions of selected para substituted trans-stilbene derivatives provide strong evidence for aggregation. A red-shifted fluorescence spectrum peaking at 420 nm gains in intensity as the stilbene concentration is increased. The excitation spectrum of this new emission is well to the red of the normal stilbene absorption spectrum, consistent with the appearance of a red shifted shoulder in the UV spectrum. Formation of a fluorescent ground state dimer (or higher aggregate) is proposed to account for these observations. The presence of polar substituents is crucial to the formation of this ground state complex.

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Saturated Absorption Spectroscopy of 13C2H2 in the Near Infrared Region

  • Moon, H. S.;Lee, W. K.;Suh, H. S.
    • Journal of the Optical Society of Korea
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    • 제8권1호
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    • pp.1-5
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    • 2004
  • Using the external cavity spectroscopy method, we have observed the saturated absorption spectrum of the P(16) line of the v$_1$+v$_3$ band of $^{13}C$_2$H$_2$$. The frequency of a laser has been stabilized to the saturated absorption spectrum. The relative contrast of the saturation spectrum is about 7% with respect to the linear absorption and the linewidth is about 1.8 MHz. The frequency fluctuation of the stabilized LD is about $\pm$ 20 KHz for a sampling time of 100 ms.

국내 지진동 특성에 대한 기기 용접 정착부의 비탄성에너지 흡수계수를 고려한 지진취약도 평가 (Seismic Fragility Analysis of Equipment Considering the Inelastic Energy Absorption Factor of Weld Anchorage for Seismic Characteristics in Korea)

  • 임승현;김건규;최인길;곽신영
    • 한국지진공학회논문집
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    • 제27권1호
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    • pp.69-75
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    • 2023
  • In Korea, most nuclear power plants were designed based on the design response spectrum of Regulatory Guide 1.60 of the NRC. However, in the case of earthquakes occurring in the country, the characteristics of seismic motions in Korea and the design response spectrum differed. The seismic motion in Korea had a higher spectral acceleration in the high-frequency range compared to the design response spectrum. The seismic capacity may be reduced when evaluating the seismic performance of the equipment with high-frequency earthquakes compared with what is evaluated by the design response spectrum for the equipment with a high natural frequency. Therefore, EPRI proposed the inelastic energy absorption factor for the equipment anchorage. In this study, the seismic performance of welding anchorage was evaluated by considering domestic seismic characteristics and EPRI's inelastic energy absorption factor. In order to reflect the characteristics of domestic earthquakes, the uniform hazard response spectrum (UHRS) of Uljin was used. Moreover, the seismic performance of the equipment was evaluated with a design response spectrum of R.G.1.60 and a uniform hazard response spectrum (UHRS) as seismic inputs. As a result, it was confirmed that the seismic performance of the weld anchorage could be increased when the inelastic energy absorption factor is used. Also, a comparative analysis was performed on the seismic capacity of the anchorage of equipment by the welding and the extended bolt.

1550 nm 영역에서 아세틸렌 분자의 포화흡수분광 (Saturated absorption spectroscopy of 13C2H2 in the 1550 nm region)

  • 문한섭;이원규;서호성
    • 한국광학회지
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    • 제15권2호
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    • pp.177-182
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    • 2004
  • 우리는 외부공진분광법을 이용하여 $^{13}$C$_2$H$_2$ 분자의 회전-진동전이의 V$_1$+V$_3$ 밴드 P(16)전이선의 포화흡수신호를 관측하고, 이 포화 흡수 스펙트럼을 이용하여 1550 nm 영역에서 반도체 레이저 주파수 안정화를 수행하였다. 측정된 포화흡수 스펙트럼의 크기는 선형 흡수에 대해서 약 7%이고, 선폭은 약 1.8 MHz로 측정되었다. 반도체 레이저 주파수를 $^{13}$C$_2$H$_2$ 분자P(16) 전이선에 안정화했을 때 안정화된 레이저의 상대주파수 흔들림은 게이트 시간 0.1 s에서 약 $\pm$20 KHz로 측정되었다.