• 제목/요약/키워드: $\gamma$-spectroscopy

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Analysis of Protein and Moisture Contents in Pea(Pisum sativum L. Using Near-Infrared Reflectance Spectroscopy

  • Jung, Chan-Sik;Kim, Byung-Joo;Kwon, Yil-Chan;Han, Won-Young;Kwack, Yong-Ho
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.43 no.2
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    • pp.101-104
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    • 1998
  • This study was conducted to establish a rapid analysis method for determining protein and moisture contents of pea. Ninety and eighty pea (Pisum sativum L.) lines were analyzed to determine protein and moisture contents, respectively using near-infrared reflectance spectroscopy. Simple correlations (${\gamma}$) of protein content in a ground sample and an intact grain sample by an automatic regression method were 0.978 and 0.910, respectively. Simple correlations by partial least square regression/principal component analysis (PLS/PCA) methods were 0.982 and 0.925, respectively. Standard error of performance (SEP) in protein content was the lowest value, 0.446 in ground sample by PLS/PCA methods. Simple correlation of moisture content was the highest at 0.871 in ground samples. when using a standard regression method. Accuracy for the moisture content was slightly lower than for protein content. It was concluded that the NIRS method would be applicable only for rapid determination of protein content in pea.

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Effect of γ-Irradiation on the Molecular Properties of Myoglobin

  • Lee, Yong-Woo;Song, Kyung-Bin
    • BMB Reports
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    • v.35 no.6
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    • pp.590-594
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    • 2002
  • To elucidate the effect of gamma-irradiation on the molecular properties of myoglobin, the secondary and tertiary structures, as well as the molecular weight size of the protein, were examined after irradiation at various irradiation doses. Gamma-irradiation of myoglobin solutions caused the disruption of the ordered structure of the protein molecules, as well as degradation, cross-linking, and aggregation of the polypeptide chains. A SDS-PAGE study indicated that irradiation caused initial fragmentation of the proteins and subsequent aggregation, due to cross-linking of the protein molecules. The effect of irradiation on the protein was more significant at lower protein concentrations. Ascorbic acid protected against the degradation and aggregation of proteins by scavenging oxygen radicals that are produced by irradiation. A circular dichroism study showed that an increase of the irradiation decreased the a-helical content of myoglobin with a concurrent increase of the aperiodic structure content. Fluorescence spectroscopy indicated that irradiation increased the emission intensity that was excited at 280 nm.

고분자 물질을 사용한 토양 중 방사성 핵종의 고정화

  • 원휘준;김계남;김민길;오원진
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2003.09a
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    • pp.293-297
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    • 2003
  • A series of laboratory experiments was conducted to investigate the fixation characteristics of poly(vinylalcohol)-poly(methacrylic acid)(PVA-PMAA) mixed solution on the soluble (equation omitted)-radionuclides. Using the potentiometric titration technique, it was found out that the PVA and PMAA in a solution form intermacromolecular complex. The mobilized portion of each radionuclide by water from sand surface treated with a fixative was measured by ${\gamma}$-ray spectroscopy, The mobilized portion of minor radionuclides such as $^{241}$ Am, $^{154}$ Eu, $^{155}$ Eu and $^{144}$ Ce were higher than those of $^{134}$ Cs and $^{137}$ Cs. The capability of PVA-PMAA system was better among the candidate solutions for the fixation of total (equation omitted)-radioactivity, $^{134,137}$Cs which is composed of more than 85 % of total ${\gamma}$-radioactivity could be fixed effectively by the PVA-PMAA solution.

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Study on Thermal Neutron Efficiency for Neutron Induced Prompt Gamma-ray Spectrometer Using Various Reflectors (즉발감마선 계측시스템의 반사체를 이용한 열중성자 효율증대 연구)

  • Park, Y.J.;Song, B.C.;Jee, K.Y.
    • Analytical Science and Technology
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    • v.16 no.5
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    • pp.426-429
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    • 2003
  • Neutron induced prompt gamma-ray spectroscopy (NIPS) system equipped with a $^{252}Cf$ neutron source and a n-type coaxial HPGe detector was installed for the quantitative analysis of aqueous samples in KAERI, Korea. Since the thermal neutron flux for the $^{252}Cf$ neutron source is relatively low compared to that for the reactor, the use of a thermal neutron reflector in the NIPS system may lead to improved results. The enhancement by using various reflectors was carried out by comparing the Cl peak with or without a cadmium plate between sample and the $^{252}Cf$ source. The use of pyrolitic graphite as a reflector provided a good result.

GRB 140304A at z=5.283: Implications on the high redshift universe and the observed flaring activities

  • Jeong, Soomin
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.1
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    • pp.38.1-38.1
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    • 2016
  • Gamma ray burst, the most brightest explosion phenomena in the current universe is well suited for study of high redshift universe. We report the afterglow multi-wavelength observation and GTC spectroscopy follow up of GRB 140304A which was exploded at z=5.283. The spectrum was shown damped Lyman alpha features and a series of absorption lines S, Si, SiII*, Oi, CII, CII*, SiIV are clearly detected at common redshift. Clear optical flares are detected when X-ray flare happened and a possible gamma-ray excess also. At this conference, we report on implications for the GRB host and environments using its absorption features which place the results in context to other well studied high redshift GRBs and studies about the ejecta using its observed flaring activities.

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A Possible Enzymatic Catabolism of L-Ascorbic Acid via $\alpha$-Ketoaldehydes (L-Ascorbic Acid의 생체분해)

  • 강사욱
    • Korean Journal of Microbiology
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    • v.23 no.4
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    • pp.302-308
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    • 1985
  • It is shown by means of nuclear magnetic resonance spectroscopy that 3,4,5-trihydroxy-2-keto-L-valeraldehyde (L-xylosone), an ${\alpha}$-ketoaldehyde, is formed during the oxidative catabolism of L-ascorbic acid. It is proposed that this substance serves as a substrate for the glyoxalase system by which it is transformed to L-xylonic acid. As L-xylonic acid is further oxidized to L-erythroascorbic acid, a biochemical pathway is proposed for the action of vitamin C which consists of two further ${\gamma}$-lactones and three different substrates of the glyoxalase system.

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Molybdenum(VI), -(V), and -(IV) Oxo Complexes with S-methyl 3-(2-hydroxypheny)methylenedithiocarbazate and Its Derivatives

  • Hee-Jung Kim;Bon-Kweon Koo
    • Bulletin of the Korean Chemical Society
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    • v.15 no.9
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    • pp.766-771
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    • 1994
  • A number of molybdenum(VI), -(V), and -(IV) oxo complexes with S-methyl 3-(2-hydroxyphenyl)methylenedithiocarbazate and its derivatives as the ONS-donor metal-binding substrate are synthesized. The Mo(VI)-dioxo complexes are cis-dioxo Mo$O_2$L(D), where D is solvent molecules such as MeOH, DMF, Py(pyridine), DMSO, and ${\gamma}$-Pic(${\gamma}$-picoline). The Mo(V)-oxo complexes are of the type (PyH)[MoO(NCS$)_2$L] with an octahedral geometry. The Mo(IV)-oxo complexes, MoOL are derived from corresponding Mo(VI)-dioxo complexes by oxo abstraction with PP$h_3$. The complexes are characterized by IR, $^1$H-NMR, UV-Vis spectroscopy and cyclic voltammetry. On the basis of ligand displacement reaction, the qualitative order of D binding for Mo$O_2$L(D) complexes is also discussed.

Measurement of deuterium concentration in heavy water utilizing prompt gamma neutron activation analysis (PGNAA) in comparison with MCNPX simulation results

  • Saeed Salahi;Mahdieh Mokhtari Dorostkar ;Akbar Abdi Saray
    • Nuclear Engineering and Technology
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    • v.54 no.11
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    • pp.4231-4235
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    • 2022
  • Considering the importance of deuterium in nuclear science including medical and industrial researches such as (BNCT) and nuclear reactors respectively, it is important to study various possible ways in addition to common methods for measuring its concentration. This study is an effort to measure deuterium concentration using PGNAA. The main idea is to calculate the area under 2.23 MeV gamma-rays photo peak resulting from neutron collision with Hydrogen atoms which are in mix with deuterium in samples. The study carried out by both simulation and experiment. Monte Carlo MCNPX2.6 code has been used for simulation and based on its acceptable results an experimental setup has been arranged. The coordination of results was in the range of R = 0.99 and R = 0.98 in simulation and experiment respectively. The accuracy of the study has been investigated by measuring the concentration of an unknown sample by both PGNAA and Fourier transform infrared spectroscopy (FT-IR) methods in which there were acceptable correlation between these two methods.

A Comparative Study of Branching Ratio of 167Yb Radioactive Isotope from Gamma-ray Spectrum Produced by 169Tm(p,3n)167Yb Reaction with 100-MeV Proton Beam (100-MeV 양성자 빔을 이용하여 169Tm(p,3n)167Yb 반응에 의해 생성된 167Yb 방사성동위원소에서 방출되는 감마선 스펙트럼 비교 연구)

  • Sam-Yol, Lee
    • Journal of the Korean Society of Radiology
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    • v.16 no.7
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    • pp.953-960
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    • 2022
  • The measurement of branching ratio of 167Yb radioactive isotopes from gamma-ray spectrum of 169Tm(p,3n)167Yb reaction were performed by using a 100-MeV proton linear accelerator of the Korea Multi-purpose Accelerator Complex (KOMAC). The 167Yb isotope has a half-life of 17.5 minutes and decays to 169Tm. The gamma rays generated from the 167Yb isotope were measured using an HPGe detector gamma ray spectroscopy system. The energy calibration of the detector and the efficiency measurement of the detector were determined using a standard source. The gamma rays of known main energy (62.9, 106.2, 113.3, 143.5 and 176.3 keV) were measured. On the other hand, information about the intensity of the generated gamma rays is very inaccurate. Therefore, in this study, the decay strength of the main gamma rays was accurately measured. Overall, it was different from the previously known results, and in particular, it was found that the intensity of the main decay gamma ray, such as the 113.3 and 106.2 keV gamma ray, was overestimated, and it was found that the gamma ray, such as 62.9, 116.7 and 143.5 keV was underestimated. The present results are considered to be important information in the fields of nuclear fusion, astrophysics and nuclear physics in the future.

Detection of Gamma-Irradiated Wheat Flour and Glutinous Rice Flour by Measuring Free Radical (Free radical의 측정을 통한 감마선 조사된 밀가루와 찹쌀가루의 검지)

  • Lee, Eun-Jeong;Yang, Jae-Seung
    • Korean Journal of Food Science and Technology
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    • v.34 no.2
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    • pp.170-173
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    • 2002
  • Electron spin resonance (ESR) spectroscopy was used to detect free radicals in irradiated wheat flour and glutinous rice flour. They were irradiated with doses of 0, 0.1, 0.5, 1 and 2 kGy at room temperature using a Co-60 irradiator. Free radicals detected for irradiated wheat flour and glutinous rice flour were higher than those of unirradiated ones. Since concentration of free radicals linearly increased with applied doses $(0.1{\sim}2\;kGy)$, highly positive correlation coefficients $(R^2=0.9995{\sim}0.9998)$ were obtained between irradiation doses and free radical concentrations right after irradiation. Although concentration of free radicals slowly decreased with storage time, the characteristic ESR signals of free radical in irradiated samples were observed even after 4 weeks of storage at room temperature.