• 제목/요약/키워드: spectroscopic methods

검색결과 633건 처리시간 0.04초

왕불류행의 Ecdysteroid성분 (Ecdysteroids from Melandrii Herba)

  • 김호경;전원경;고병섭
    • 약학회지
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    • 제45권5호
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    • pp.455-459
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    • 2001
  • Melandrii Herba has been used for tympanitis, sore throat, dysentery and dehumidifying diuretic. From the BuOH fraction of methanol extracts, three ecdysteroids (ecdysterone, ecdysterone 22-acetate and inokosterone) were isolated by column chromatography using Amberlite XAD-4, ODS and Sephadex LH-20 gel and by HPLC method. The structures of these compounds were identified on the basis of spectroscopic methods.

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Synthesis of Substituted Phenyltrichlorocyclopropene Derivatives Using Friedel-Crafts Reaction

  • Choi, Sam-Kwon;Suk ,Won-Kyung
    • Bulletin of the Korean Chemical Society
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    • 제2권3호
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    • pp.83-85
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    • 1981
  • Tetrachlorocyclopropene has been prepared smoothly by the dehydrochlorination of pentachlorocyclopropane which could be obtained easily from sodium trichloroacetate and trichloroethylene in 1,2-dimethoxyethane. By the reaction of aromatic hydrocarbons with tetrachlorocyclopropene and aluminium chloride, new substituted phenyltrichlorocyclopropene derivatives have been prepared. The structures of these compounds were characterized by means of spectroscopic methods.

Convolution and Deconvolution Algorithms for Large-Volume Cosmological Surveys

  • Park, KeunWoo;Rossi, Graziano
    • 천문학회보
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    • 제40권2호
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    • pp.50.4-51
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    • 2015
  • Current and planned deep multicolor wide-area cosmological surveys will map in detail the spatial distribution of galaxies and quasars over unprecedented volumes, and provide a number of objects with photometric redshifts more than an order of magnitude bigger than that of spectroscopic redshifts. Photometric information is statistically more significant for studying cosmological evolution, dark energy, and the expansion history of the universe at a fraction of the cost of a full spectroscopic survey, but intrinsically carries a bias due to noise in the distance estimates. We provide convolution- and deconvolution-based algorithms capable of removing this bias -- thus able to exploit the full cosmological information -- in order to reconstruct intrinsic distributions and correlations between distance-dependent quantities. We then show some direct applications of our techniques to the VIMOS Public Extragalactic Redshift Survey (VIPERS) and the Sloan Digital Sky Survey (SDSS) datasets. Our methods impact a broader range of studies, when at least one distance-dependent quantity is involved; hence, they will be useful for upcoming large-volume surveys, some of which will only have photometric information.

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국내 토양 휴믹물질의 특성 규명 및 DB 구축에 대한 연구 (Characterization of Humic and Fulvic Acids Extracted at the Soils of Korea and Its DB Establishment)

  • 이창훈;유지호;신현상;정근호;이창우
    • 한국지하수토양환경학회:학술대회논문집
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    • 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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    • pp.397-400
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    • 2003
  • In this study, humic and fulvic acids in soils at the vicinity of domestic atomic power plants(NPPs), located in Yungkwang(YK), Uljin(UJ), Kori(KR), Koseong(KS), Wolseong(WS) area, and in volcanic ash soils of the Cheju island(Mt. Hanla(HL), Manjanggul(MJ)) were isolated, and characterized using chemical(elemental analysis, proton exchange capacity, molecular size distribution) and spectroscopic(UV/Vis., IR, FL, $^{13}$ C NMR spectra) methods. The results were compared with one another and compiled for their DB establishments. The humic substances distribution (humic acid, fulvic acid, Humin) in the soils were also determined by IHSS standard method. Main purpose of this study was to provide a basic data needed to evaluate the effect of humic substances on the migrational behaviour of radioactive elements in contaminated surface soil.

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Spectroscopic Studies of TP6F PI Switched by Hole-Injection

  • 이경재;임규욱;김동민;이문호;강태희;정석민
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2011년도 제40회 동계학술대회 초록집
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    • pp.297-298
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    • 2011
  • Metal/poly (4,4'-aminotriphen-ylene hexafluoroisopropylidenediphthalimide) (TP6F PI)/metal structure exhibited an electrically volatile phase transition with high (OFF) or low (ON) resistive states when voltage between electrodes swept. Here, we demonstrate a noble set-up in which holes are injected by photoelectron emission process during the voltage sweep instead of direct charge carrier injection via metal electrode, which enables direct investigation into changed electronic structures of TP6F PI both in ON and OFF states using photoemission spectroscopy methods. In the I-V measurement, TP6F PI shows a non-volatile behavior. In spectroscopic results, this non-volatile behavior is leaded from the structural modification of the O=C double bond in phthalimide of TP6F PI by hole injection.

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Evaluation of the Surface Anchoring Strength by Means of Renormalized Transmission Spectroscopic Ellipsometry

  • Kimura, Munehiro;Tanaka, Norihiko;Bansho, Ryota;Akahane, Tadashi
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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    • pp.191-194
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    • 2005
  • Evaluating methods of the polar and/or azimuthal anchoring strength coefficients by means of the renormalized transmission spectroscopic ellipsometry are demonstrated. The Anchoring strength coefficients can be evaluated from the measurement of ellipsometric parameters measured by the oblique incident transmission ellipsometry, where the effect of multiplebeam interference is eliminated. The device parameters such as the pretilt angle and cell gap can be determined simultaneously even in the case of the twisted nematic liquid crystal sample cells.

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Potentially Bioactive Two New Natural Sesquiterpenoids from the Rhizomes of Zingiber zerumbet

  • Jang Dae Sik;Seol Eun Kyoung
    • Archives of Pharmacal Research
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    • 제28권3호
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    • pp.294-296
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    • 2005
  • Repeated chromatography of the n-hexane-soluble fraction of the MeOH extract of the rhizomes of Zingiber zerumbet led to the isolation of two isomers of 6-methoxy-2E,9E-humula-dien-8-one (1 and 2) and stigmast-4-en-3-one. The structures of 1 and 2 were determined by spectroscopic methods including 10 and 2D-NMR elucidated by analysis of spectroscopic data as well as by comparison with published values. This is the first report on the isolation of compounds 1 and 2 from the nature. Stigmast-4-en-3-one was first isolated from this plant.

Iminoxyl Biradical의 합성과 분광학적인 연구 (Synthesis of Iminoxyl Biradical and the Spectroscopic Study)

  • 양정성;채희주;여철현
    • 대한화학회지
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    • 제25권1호
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    • pp.13-20
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    • 1981
  • Iminoxyl biradical은 biradical spin probe로 액체결정에 주입시켜 그 결정의 director분포에 관한 역학적성질을 조사하는데 유용한 물질이다. 새로운 방법으로 iminoxyl biradical을 합성하는 과정에서 각 단계의 합성중간 생성물들을 녹는점측정과 NMR, IR, UV 및 Mass 등과 같은 분광학적인 방법으로 확인하였다. 최종 생성물인 iminoxyl biradical은 EPR 분광법으로 확인하고 두 spin간의 상호작용도 EPR peaks로 고찰하였다.

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레이저 용접시 분광학적 수법에 의한 증발입자의 거동과 플라즈마 물성의 계측 (Evaporating Particle Behaviors and plasma Parameters by Spectroscopic Method in laser Welding)

  • 김윤해
    • Journal of Advanced Marine Engineering and Technology
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    • 제23권4호
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    • pp.514-522
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    • 1999
  • The laser-induced plasma affects greatly on the results of welding process. moreover selective evaporation loss of alloying elements leads to change in chemical composition of weld metal as well as the mechanical properties of welded joint. this study was undertaken to obtain a fundamental knowledge of pulsed laser welding phenomena especially evaporation mechanism of different aluminum alloys. The intensities of molecular spectra of AlO and MgO were different each other depeding on the power density of a laser beam Under the low power density condition the MgO band spectrum was predominant in intensity while the AlO spectra became much stronger with an increase in the power density. These behaviors have been attributed to the difference in evaporation phenomena of Al and Mg metals with different boiling points and latent heats of vaporization. The time-averaged plasma temperature and electron number density were determined by spectroscopic methods and consequently the obtained temperature was $3,280{\pm}150K$ and the electron number density was $1.85{\times}10^{19}\;l/m^3$.

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