• 한국연초학회지
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• 제14권2호
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• pp.126-132
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• 1992

This experiment was conducted to examine estimates of heterosis, degree of dominance, heritability and phenotypic and genotypic correlation for several mutant characters in flue-cured tobacco variety. Significant heterosis was noted, recording 2.73 and 6.16% for leaf width, -6.86 and -4.72 for leaf shape index, 19.8 and 23.4% for bacterial wilt disease index in Fl an4 F2 generation, respectively, and -1.44 for days to flower in F2 generation. And also leaf width was appeared partial dominance in Fl, and leaf shape index in Fl and F2, Leaf width in F2 was appeared overdominance. Estimated heritabilities in the broad sense ranged from 0.77 to 0.87 for plant and stalk height and days to flower, while those of leaf number, leaf length and width, leaf shape index and bacterial wilt disease index ranged from 0.50 to 0.65. And the heritabilities in the narrow sense were appeared 0.64 and 0.72 for stalk and plant height, respectively, and the others were ranged from 0.32 to 0.47 Positive genotpic correlations appeared among plant height, stalk height, leaf length and leaf width, and between leaf shape index ands day to flower. And negative genotypic correlations appeared between leaf shape index and plant height and stalk height and leaf width, and between bacterial wilt disease index and leaf length.

• 대한수의학회지
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• 제44권1호
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• pp.41-47
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• 2004

The alkaline single-cell gel electrophoresis (SCGE) assay, called the comet assay, has been applied to detect DNA damage induced by a number of chemicals and biological factors in vivo and in vitro. The DNA damage was analysed by tail moment (TM) and tail length (TL), which were markers of DNA strand breaks in SCGE. Human, mouse and rat peripheral blood lymphocytes (PBLs) were irradiated with different doses of $^{60}Co$ ${\gamma}$-rays, e.g. 1, 2, 4, and 8 Gy at a dose rate of 1 Gy/min. A dose-dependent increase in TM (p<0.01) and TL (p<0.01) was obtained at all the radiation doses (1-8 Gy) in human, mouse and rat PBLs. Mouse PBLs were more sensitive than human PBLs which were in turn more sensitive than rat PBLs when the treated dosages were 1 and 2 Gy. However, human PBLs were more sensitive than mouse PBLs which were in turn more sensitive than rat PBLs when the irradiation dosages were 4 and 8 Gy. Data from all three species could be fitted to a linear-quadratic model. These results indicated that there may be inherent differences in the radio-sensitivity among PBLs of mammalian species.

• 한국의학물리학회지:의학물리
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• 제24권3호
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• pp.140-144
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• 2013

본 연구에서는 방사선생물 분야에서는 사용하는 세슘-137 조사기에 대한 기준 흡수선량을 측정하고 시료의 방사선량 평가에 활용하기 위하여 유리선량계를 교정하였다. 세슘-137 감마선에 대하여 IAEA TRS-277 프로토콜을 적용하여 정밀하게 물흡수선량을 결정하였다. 기준 흡수선량 측정에는 PTW-TM300013 전리함과 PTW-TM41023 물팬텀을 사용하였으며, 유리선량계는 DoseAce사의 GD-302M 모델을 사용하였다. 교정된 유리선량계의 불확도(1 SD)는 약 2.7%로 평가되며, 본 결과는 연구용 시료의 방사선량 측정에 이용될 예정이다.

• Journal of Plant Biotechnology
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• 제5권1호
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• pp.25-31
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• 2003

As a consequence of tissue culture of rice, RAPD analysis was peformed to determine whether extended culture periods as undifferentiated calli affected the subsequent genetic constancy, and whether any resulting DNA rearrangements could be detected between sibling plants produced from the same callus. Somaclonal variation was induced at the initial stage of tissue culture and it increased with the length of culture maintenance. Of the 192 total bands, the number of polymorphic bands was 22 (11.5%), 33 (17.2%), and 49 (25.5%) in the callus of 1,3, and 6 months culture, respectively. A significantly higher level of genotypic polymorphisms between regenerants from two different somaclones was also detected, although all the regenerants were derived from a single genotype. In comparison of DNA polymorphisms between regenerants from non-irradiated and from irradiated calli, a scope of variation spectrum by gamma ray irradiation was larger than that by tissue culture. Consideration must be given to this genomic variation where attempts are to be made to use desirable somaclonal variants for plant breeding purpose and in genetic engineering program.

• Nuclear Engineering and Technology
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• 제34권6호
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• pp.545-552
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• 2002

We developed an ultra low background gamma ray spectrometer particularly suitable for experiment which require lower detection limit. The background of a germanium spectrometer is suppressed by applying active and passive shielding technique at the same time. The active shielding devices consist of plastic scintillating plates of 50 mm thick and anti-coincidence electronic system. The shielding is made of 150 mm thick walls of very low activity lead,20 mm with activity of <10 Bq/kg and 130 mm with activity of <50 Bq/kg. The observed background count rates are 1.2 $s^{-1}$ and 0.36 $s^{-1}$ without and with the active shielding, respectively, overall the energy regions from 30 keV to 3 MeV The cosmic ray induced background is suppressed by a rate of 0.8 $s^{-1}$ at the present work. The detection efficiency curve necessary to obtain the radioactivity of environmental samples has been precisely determined on the energy regions from 80 to 2000 keV with a 10$^3$ ml marinelli beaker sample, consisting of the calibrated radionuclides $^{109}$ Cd, $^{57}$ CO, $^{139}$ Ce, $^{203}$ Hg, $^{113}$ Sn, $^{85}$Sr, $^{137}$ Cs, $^{60}$ Co and $^{88}$ Y. Virtues Of the method are demonstrated by measuring the activity of $^{137}$ Cs contained in the powdered milk.

• 폴리머
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• 제26권6호
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• pp.792-802
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• 2002

본 연구에서는, 방사선($^{60}$Co ${\gamma}$-rays) 가교를 이용하여 poly(vinyl alcohol)(PVA)/poly(N-vinylpyrrolidone)(PYP)/글리세린/키토산의 혼합물로부터 하이드로겔을 제조하였다 하이드로겔이 상처 치료용 드레싱으로 사용될 수 있는지 예측하기 위해 겔화율, 팽윤도, 겔강도 같은 기계적 성질을 측정하였다. PVV와 PVP의 조성비는 6 : 4, 키토산은 0.3 wt%, 글리세린은 0~5 wt%, PVA/PVP/글리세린/키토산 수용액의 고형분의 농도는 15 wt%이었다. 하이드로겔의 기계적 성질에 조사선량이 미치는 영향을 예측하기 위해 PVA/PVP/글리세린/키토산 혼합물에 25~60 kGy의 감마선을 조사하였다. 겔화율과 겔강도는 글리세린 조성비가 작을수록 조사선량이 커질수록 증가하였다. 팽윤도는 글리세린 조성비가 클수록, 조사선량이 작을수록 증가하였다. PVA/PVP/글리세린/키토산 하이드로겔에서 글리세린은 겔 모양의 변형을 막는다. 제조된 하이드로겔이 상업용 바셀린 거즈보다 치료 효과가 우수하였다.

• Nuclear Engineering and Technology
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• 제4권1호
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• pp.3-10
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• 1972

수정의 영형광 glow curve 상,"before glow"의 생성원인중의 하나가 밀폐된 제한 공간내의 산란 감마선의 기여임을 확인하기 위하여 산란선대 일차선의 기여비(S/P)를 측정하였다. 이 S/P와 "before glow"의 유효높이 ($h_{b}$)와의 상관 관계를 고찰하였는바 상관계수+0.9라는 비교적 밀접한 일차 관계가 있음을 알았으며 이는 에너지가 감소된 산란 선에 의하여 여기되었던 전자가 본래 일차선으로 여기되었던 전자보다 얕은 trap에 걸려 있었음을 입증하는 것으로 보인다. 한편 $h_{b}$와 glow curve의 전면적 (At)의 비 및 "before glow"의 유효면적(Ab)과 At 와의 비가 S/P와 어떤 관계에 있는가도 조사하였는데 이들의 관계는 단순하지 않으며 다만 S/P 값이 0.035 보다 큰 영역에서는 간단한 대수함수로 표현되었다. 끝으로 자연수정을 TLD로 사용할 경우 그 재사용을 위한 선량한계를 살펴본 결과 그것은 $10^{5}$ R 정도임을 알아내었다.

• 한국막학회:학술대회논문집
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• 한국막학회 1998년도 춘계 총회 및 학술발표회
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• pp.99-101
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• 1998

1. Introduction : The conventional grafting polymerization technique requires chemically reactive groups on the surface as well as on the polymer chains. For this reason, a series of prefunctionalization steps are necessary for covalent grafting. The surface prefunctionalizational technique for grafting can be used to ionization radiation, UV, plasma, ion beam or chemical initiators. Of these techniques, radiation method is one of the useful methods because of uniform and rapid creation of active radical sites without catalytic contamination in grafted samples. If the diffusion of monomer into polymer is large enough to come to the inside of polymer substrate, a homogeneous and uniform grafting reaction can be carried out throughout the whole polymer substrate. Radiation-induced grafting method may attach specific functional moieties to a polymeric substrate, such as preirradiation and simultaneous irradiation. The former is irradiated at backbone polymer in vacuum or nitrogen gas and air, and then subsequent monomer grafting by trapped or peroxy radicals, while the latter is irradiated at backbone polymer in the presence of the monomer. Therefore, radiation-induced polymerization can be used to modification of the chemical and physical properties of the polymeric materials and has attracted considerable interest because it imparts desirable properties such as blood compatibility. membrane quality, ion excahnge, dyeability, protein adsorption, and immobilization of bioactive materials. Synthesizing biocompatible materials by radiation method such as preirradiation or simultaneous irradiation has often used $\gamma$-rays to graft hydrophilic monomers onto hydrophobic polymer substrates. In this work, in attempt to produce surfaces that show low levels of anti-fouling of bovine serum albumin(BSA) solutions, hydroxyethyl methacrylate(HEMA) was grafted polypropylene membrane surfaces by preirradiation technique. The anti-fouling effect of the polypropylene membrane after grafting was examined by permeation BSA solution.

• 천문학논총
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• 제30권2호
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• pp.565-568
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• 2015

In this work, we study the correlation between the photon index (${\Gamma}$) of the X-ray spectrum and the 2-10 keV X-ray luminosity ($L_X$) for black hole X-ray binaries (BHBs). The BHB sample is mainly from the quiescent, hard and intermediate states, with values of $L_X$ ranging from ${\sim}10^{30.5}$ to $10^{37.5}$ erg $s^{-1}$. We find that the photon index ${\Gamma}$ is positively or negatively correlated with the X-ray luminosity $L_X$, for $L_X$ above or below a critical value, ${\sim}10^{36.5}$ erg $s^{-1}$. This result is consistent with previous works. Moreover, when $L_X{\leq}{\sim}10^{33}$ erg $s^{-1}$, we found that the photon index is roughly independent of the X-ray luminosity. We interpret the above correlations in the framework of a coupled hot accretion flow - jet model. Besides, we also find that in the moderate-luminosity region, different sources may have different anti-correlation slopes, and we argue this diversity is caused by the different value of ${\delta}$, which describes the fraction of turbulent dissipation that directly heats electrons.

• Nuclear Engineering and Technology
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• 제50권3호
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• pp.470-477
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• 2018

With a highly functional methyl vinyl silicone rubber (VMQ) matrix and filler materials of $B_4C$, PbO, and benzophenone (BP) and through powder surface modification, silicone rubber mixing, and vulcanized molding, a flexible radiation shielding and resistant composite was prepared in the study. The dispersion property of the powder in the matrix filler was improved by powder surface modification. BP was added into the matrix to enhance the radiation resistance performance of the composites. After irradiation, the tensile strength, elongation, and tear strength of the composites decreased, while the Shore hardness of the composites and the crosslinking density of the VMQ matrix increased. Moreover, the composites with BP showed better mechanical properties and smaller crosslinking density than those without BP after irradiation. The initial degradation temperatures of the composites containing BP before and after irradiation were $323.6^{\circ}C$ and $335.3^{\circ}C$, respectively. The transmission of neutrons for a 2-mm thick sample was only 0.12 for an Am-Be neutron source. The transmission of ${\gamma}$-rays with energies of 0.662, 1.173, and 1.332 MeV for 2-cm thick samples were 0.7, 0.782, and 0.795, respectively.