• Title/Summary/Keyword: light spectra

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Calculation of Proton-Induced Reactions on Tellurium Isotopes Below 60 MeV for Medical Radioisotope Production

  • Kim, Doohwan;Jonghwa Chang;Yinlu Han
    • Nuclear Engineering and Technology
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    • v.32 no.4
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    • pp.361-371
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    • 2000
  • The 123Te(p,n)123I, 124Te(p,n)124I and 124Te(p,2n)123I reactions, among the many reaction channels opened, are the major reactions under consideration from a diagnostic purpose because reaction residuals as the gamma emitters are used for most radiophamaceutical applications involving radioiodine. Based on the available experimental data, the absorption cross sections and elastic scattering angular distributions of the proton-induced nuclear reaction on Te isotopes below 60 MeV are calculated using the optical model code APMNK. The transmission coefficients of neutron, proton, deuteron, trition and alpha particles are calculated by CUNF code and are fed into the GNASH code. By adjusting level density parameters and the pair correction values of some reaction channels, as well as the composite nucleus state density constants of the pre-equilibrium model, the production cross sections and energy-angle correlated spectra of the secondary light particles, as well as production cross sections and energy distributions of heavy recoils and gamma rays are calculated by the statistical plus pre-equilibrium model code GNASH. The calculated results are analysed and compared with the experimental data taken from the EXFOR. The optimized global optical model parameters give overall agreement with the experimental data over both the entire energy range and all tellurium isotopes.

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Charge Redistribution of Pt-based Alloys

  • Lim, K.Y.;Chung, Y.D.;Kwon, S.Y.;Lee, Y.S.;C.N.Whang;Y.Jeon;Park, B.S.
    • Proceedings of the Korean Vacuum Society Conference
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    • 1999.07a
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    • pp.171-171
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    • 1999
  • We studied the charge redistribution in the Pt-M (M=Cu, Co) alloys by X-ray Absorption Near Edge Spectroscopy(XANES) and X-ray Photoelectron Spectroscopy(XPS). These analysis tools provide us information about the charge transfer in the valence band of intermetallic bonding. The samples were prepared by arc-melting method. After annealing this samples in vacuum for several hours, we cold get the ordered samples, which were confirmed with XRD analysis. the core and valence level energy shift in these system were investigated by Mg $K\alpha$(1253.6eV) x-ray source for Pt-Co alloys and monochromatized Al $K\alpha$ (1486.6eV) for Pt-Cu alloys. Pt L2, L3-edge, and Cu, Co K-edge XANES spectra were measured with the total electron-yield mode detector at the 3Cl beam line of the PLS (Pohang light source0. from the changes of White line (WL) area and the core level shifts of the each metal sites, we can obtain the information about the electrons participating in the intermetallic bonding of the Pt-Cu and Pt-Co alloys.

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The 105-month Swift-BAT all-sky hard X-ray survey

  • Oh, Kyuseok;Koss, Michael;Markwardt, Craig B.;Schawinski, Kevin;Baumgartner, Wayne H.;Barthelmy, Scott D.;Cenko, Bradley;Gehrels, Neil;Mushotzky, Richard;Petulante, Abigail;Ricci, Claudio;Lien, Amy;Trakhtenbrot, Benny
    • The Bulletin of The Korean Astronomical Society
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    • v.43 no.1
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    • pp.36.3-37
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    • 2018
  • We present a new catalog of hard X-ray sources detected in the first 105 months of observations with the Burst Alert Telescope (BAT) on board the Neil Gehrels Swift observatory. The 105 month Swift-BAT survey is a uniform hard X-ray all-sky survey performed in the 14-195 keV band. The Swift-BAT 105 month catalog provides 1632 (422 new detections) hard X-ray sources in the 14 - 195 keV band above the 4.8 sigma significance level. Adding to the previously known hard X-ray sources, 34% (144/422) of the new detections are identified as Seyfert AGN in nearby galaxies (z < 0.2). The majority of the remaining identified sources are X-ray binaries (7%, 31) and blazars/BL Lac objects (10%, 43). As part of this new edition of the Swift-BAT catalog, we release eight-channel spectra and monthly sampled light curves for each object in the online journal and at the Swift-BAT 105 month Web site.

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Influence of Fluxing Agents in Sr3SiO5:Eu2+ Phosphors for Fabrication of Warm White Light Emitting Diodes (따뜻한 백색 LED의 제조를 위한 Sr3SiO5:Eu2+ 형광체에서의 융제 첨가 영향)

  • Kim, Hyun-Ho;Chung, Kang-Sup;Lee, Seoung-Won;Kim, Byoung-Gyu
    • Journal of the Korean Ceramic Society
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    • v.49 no.1
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    • pp.105-110
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    • 2012
  • In this paper, a yellow phosphor $Sr_3SiO_5:Eu^{2+}$ that emits efficiently at the 450 nm excitation for warm white LED is studied. In addition, the effects of various flux $BaF_2$, $NH_4Cl$ on the emission spectra were investigated. The samples were synthesized through conventional solid state reaction under reducing atmosphere of 95% $N_2$-5% $H_2$ mixture at the high temperature. All phosphors showed a excitation band from 450 nm and broad band emission peaking at region of 580 nm. The optimal concentration of $BaF_2$ flux is 3 wt% for $Sr_3SiO_5$ with doping 0.05mol Eu phosphors fired in a reductive atmosphere. The phosphor showed highest emission peaking at 582 nm.

Regulation of Chlorophyll-Protein Complex Formation and Assembly in Wheat Thylakoid Membrane

  • Guseinova, I.M.;Suleimanov, S.Y.;Aliev, J.A.
    • BMB Reports
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    • v.34 no.6
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    • pp.496-501
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    • 2001
  • Lincomycin, an inhibitor of plastid protein synthesis, was found to block the synthesis of apoprotein P700 with a molecular mass of 72 kDa and the assembly of the Chl a-protein of PS I. Synthesis of the polypeptides of 48, 43.5, and 32 kDa of the PS II complex is also suppressed. This process is accompanied by the disappearance of the PS Two reaction center Chl a at 683 nm, and of the PS One reaction center Chl a at 690, 696, and 705 nm on the fourth derivative of the absorption spectra at 77K. Lincomycin does not affect the synthesis of LHC subunits. It increases the content of the two main Chl forms of LHC at 648 nm (Chl b) and 676 nm (Chl a). The low-temperature fluorescence ratio F736/F685 is also increased. However, the effect of cycloheximide (an inhibitor of cytoplasmic protein synthesis) leads to the reduction of polypeptides of the light-harvesting Chl a/b-protein complex in the range of 29.5-22 kDa. Under these conditions, the relative amount of Chl b and the F736/ F685 fluorescence ratio decrease significantly. This is obviously the result of blocking the LHC I and LHC II synthesis. At the same time rifampicin and actinomycin D (inhibitors which block transcription in chloroplast and nuclear genome, respectively) inessentially affect the characteristics of these complexes.

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A study on the development of oxygen measurement device for diagnosis of peripheral vascular disease in lower extremity (하지 (下脂) 조직내의 말초 혈관계 질환 진단을 위한 산소 측정장치의 개발에 관한 연구)

  • 임현수;이준규;박동철
    • Progress in Medical Physics
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    • v.10 no.1
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    • pp.9-15
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    • 1999
  • The oxygen saturation of blood can be measured by the difference absorption in optical spectra of Hb and Hb0$_2$, as the well known previous study. In this study we developed the non-invasive oxygen measurement device for diagnosis of peripheral vascular disease in lower extremity using infrared and red LED which produce a peak spectral emission at a wavelength of 660 nm, and 940 nm. To evaluate the clinical application of the oxygen measurement device, we performed lower extremity study to measure the oxygen changes in response to physiological changes within biological tissue. The results showed that oxygen saturation of blood in biological tissue can be monitored from the separation arrangement light source and detector.

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Luminescent Properties of the $Tb^{3+}$-Activated $ABCO_4$ and $ABC_3O_7$ Phosphors (A=Ca, Sr ; B=Y, RE ; C=AI, Ga)

  • Kim, Chang-Hae;Park, Sang-Mi;Park, Joung-Kyu;Park, Hee-Dong;Park, Joon-Taik
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.635-638
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    • 2002
  • In $ABCO_4$ and $ABC_3O_7$ (A=Ca, Sr; B=Y, Rare earth; C=Al, Ga), random distribution of static crystalline fields in activator sites results in inhomogeneous broadening of spectral lines of luminescent materials. In this study, we investigated luminescent properties of above-mentioned materials by excitation and emission spectra. In result, both $ABCO_4$:Tb and $ABC_3O_7$:Tb phosphors emit the green light. $ABC_3O_7$:Tb phosphors absorbed shorter wavelength energy than $ABCO_4$ phosphors so that the emission efficiencies of $ABC_3O_7$:Tb phosphors were higher than those of $ABCO_4$:Tb phosphors under vacuum UV.

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Formation of Oxidative Cleavage from Phytofluene by Autoxidation (자동산화에 의한 Phytofluene으로부터 산화개열산물의 생성)

  • 김선재
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.29 no.4
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    • pp.568-574
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    • 2000
  • Phytofluene was subjected to ozonolysis in ice-cold dichloromethane. The ozonolysis products were fractionated with a silica column and the carbonyl fraction was analyzed by ODS-HPLC with a photodiode array detector. Phytofluene was solubilized in 5% tween 40, and then oxidized by incubating under dim yellow light at 37$^{\circ}C$, 24 hr with continuous shaking. Carbonyl compound and acidic compound were produced. In comparison with autoxidation and ozonolysis, each compound showed the same retention time and UV-vis spectra were identical to the reference cleavage products prepared by ozeonolysis of phytofluene. Absorption spectrum of acidic compound was similar to that of standard 4,5-didehydrogeranyl geranyl acid which is known to possess biological activity. Thus, eccentric cleavage of phytofluene was confirmed to occur in vitro under oxidation condition.

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Characteristics of the Purple Pigment Compound in Halophytic Plant, Suaeda japonica (내염성 식물 칠면초 (Suaeda japonica )가 갖는 자색 색소의 특징)

  • Chung, Sang-Ho
    • Proceedings of the Korea Contents Association Conference
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    • 2013.05a
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    • pp.361-362
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    • 2013
  • As one of the steps toward understanding how the plant is well adapted to strongly saline habitats, the purple pigment compound that is accumulated in Suaeda japonica was extracted and characterized. The extracted pigment compound exhibited typical characteristics of betacyanin that were represented by water solubility, pH- and temperature-dependent color changes, sensitivity to light, UV-Vis spectra, and gel electrophoretic migration pattern. LC-MS of the extracted pigment compound showed the presence of two major protonated molecular ions ($[M+H]^+$) at m/z 651.1 and m/z 827.1. According to the DPPH assay, it was found to have an antioxidant activity that is linearly increased in proportion to the reaction time for up to 30 min, and the activity was comparable to that of control BHA at 9.0 mg/ml. The cytotoxic activity against several tumor cell lines was also examined following the MTT assay. The significant growth inhibitory effect was observed on two tumor cell lines, SW-156 (human kidney carcinoma) and HEC-1B (human endometrial adenocarcinoma). Probably, the pigment compound may function as an osmolyte to uphold halotolerant physiological processes in saline environment.

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A Study on the Development of Noninvasive Tissue-Reflectance Oximeter (Noninvasive Tissue-Reflectance Oximeter의 개발에 관한 연구)

  • Chang, S.Y.;Kim, N.J.;Koo, C.H.;Lee, J.K.;Lim, H.S.
    • Proceedings of the KOSOMBE Conference
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    • v.1997 no.11
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    • pp.420-423
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    • 1997
  • The oxygen saturation of blood can be measured by sensing the difference absorption in optical spectra of Hb and $HbO_2$, as the well known previous study. [1] In this study we developed the noninvasive tissue reflectance oximeter(TRO) using three kinds of LEDs which produce a peak spectral emission at a wavelength of 565, 660 and 940nm. And we tested the unction of the TR oximeter by comparing the output signals measured on normal tissue to measured on low oxygenated tissue. The results showed that oxygen saturation of blood and biological tissue can be monitored from the separation arrangement light source and detector.

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