• Nuclear Engineering and Technology
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• 제31권6호
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• pp.529-540
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• 1999

As part of IAEA CRP on "Compilation and evaluation of photonuclear data for applications", we evaluated photoproduction data of Mo, Zn, S and Cl isotopes for medical use and biological applications. Available experimental data were collected and their discrepancies were analyzed to select or reconstruct the representative data set. The photoabsorption cross sections were then evaluated tv applying the Giant Dipole Resonance (GDR) model for the energies below about 30 MeV and the quasi-deuteron model for energies below 140 MeV. The resulting representative photoabsorption data were given as input for the theoretical calculations for the emission process of light nuclei including neutron, proton, deuteron, triton, $^3He$, alpha particles and gamma rays by use of the Hauser-Feshbach and the preequilibrium model.

• 천문학회보
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• 제39권2호
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• pp.39-39
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• 2014

Studies of compact radio sources since the discovery of quasars have revealed a variety of physical properties: both in morphology and kinematics from sub-parsec to Mega-parsec scales, radiation mechanisms at frequencies from the radio to ${\gamma}$-rays, theoretical models for relativistic jets, etc. The frontier discovery of Very Long Baseline Interferometry (VLBI) observations for the compact extragalactic radio sources have triggered the extensive studies to investigate the underlying physics of the relativistic jets. In this context, the highest resolution VLBI surveys of ultra-compact radio sources provide the potentially important statistical basis for future study. As a tool of this study, a new millimeter VLBI network in Korea, the Korean VLBI Network (KVN) will paly an important role. We present results from large VLBI surveys of compact radio sources at millimeter wavelengths and discuss the prospects with the KVN on this study.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1835-1837
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• 2001

The interference of electromagnetic waves in factory is increasing according with development of industrial society and many use of electrical machinery. Electromagnetic wave is defined as the electrical and magnetic field formed by electrical and electronic equipment used in daily lives, which indiscriminatingly affects the human health and operation of machinery. The electromagnetic spectrum ranges from the shorter wavelengths(including gamma and x-rays) to the longer wavelengths(including microwaves and broadcast radio waves). Radiation that is not absorbed or scattered in the atmosphere can reach and affect on the operation of machine. In this study, electromagnetic wave that is interfered to the machine and human is detected in factory, and decrease method of electromagnetic wave interference is studied.

• 미생물학회지
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• 제15권2호
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• pp.63-76
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• 1977

Irradiation with high doses of gamma rays induced the reduction of mycelial weight and anaylase activity, and increased relative amylase activity in surface cultures. Biphase in growth curves was shown in aeration-agitation cultures but the behavior of the first phase of growth could be eliminated by replacing the amylasehydrolysed starch substrates, so that enzyme production was shortened ca. 40 hours and relative amylase activity was increased about 3 times higher before onset of autolysis. In the effect of gibberellin on amylase production, the positive stimulation was appeared to only surface culturs of the liquid medium and the negative effect to shake-cultures in a mutant. Trials of various continuous culture were resulted not only the approalch to the value of amylase activity in surface cultures of liquid medium, but also higher productivity than in batch cultures. The culture-degeneration was observed in two-stage continuous culture, but did not appear in continuous elevation culture.

• Journal of Radiation Protection and Research
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• 제19권1호
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• pp.37-50
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• 1994

X-선과 감마선의 에너지에 따른 선질특성과 선량 및 필름의 사진농도와의 관계를 이용한 필름배지선량계의 선량환산식을 실험적으로 체계화 하였고, 시간경과에 따른 잠상퇴행 특성과 방사선의 입사방향에 따른 방향특성을 실험적으로 조사하여 보정계수를 산출하였다. 본 연구에서 구한 선량환산식은 필름배지선량계의 기술기준인 성능판정 기준을 잘 만족시키는 것으로 나타났다.

• 천문학회지
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• 제38권3호
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• pp.339-344
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• 2005

We present analysis results of the energy spectra of MCG-2-58-22 associated with occasional flares which appear in a long-term X-ray light curve. We measure an intrinsic power-law slope of this object to be ${\Gamma}=1.74{\pm}0.02$ in the energy range of ${\sim}1-5keV$ and find that this slope is little affected by flares. We confirm that there exists a broad excess emission above 5 keV to the power-law continuum. The excess emission is less variable compared with a flux variation of flare and tends to be relatively weak during flares. A soft X-ray spectrum is also found to change, implying the presence of a variable soft component. We discuss the implications of these spectral variations.

• 한국정보통신학회논문지
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• 제18권6호
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• pp.1488-1493
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• 2014

전 세계적으로 해운물류 안전 보안체계가 강화됨에 따라 국가물류보안 체계 구축을 위한 해운물류 안전 보안 핵심기술 개발이 이루어지고 있다. 이러한 국제적 정서에 발맞추어, 국내에서도 감마선 핵종을 검출할 수 있는 휴대용 방사선 검출 장치에 대한 관심이 높아지고 있다. 본 논문에서는 Cortex-A9을 이용한 휴대용 방사선 검출장치 플랫폼 검출 성능의 향상을 위한 연구하였다.

• 천문학회보
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• 제37권2호
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• pp.129.2-129.2
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• 2012

Solar flares and coronal mass ejections (CMEs) are two major solar eruptive phenomena which can cause enormous economic and commercial losses: (1) flares are sudden, rapid, and intense brightenings from radio waves to Gamma-rays in the chromosphere and corona, and (2) CMEs are large-scale transient eruptions of magnetized plasma from the solar corona that propagate outward into interplanetary space. Most flares and CMEs occur in magnetically complicated solar active regions (ARs). Therefore, it is crucial to investigate magnetic fields in ARs and their temporal variations for understanding a precondition and a trigger mechanism related to flare/CME initiation. In this presentation, we will introduce an automated system for empirical forecasting of flares and CMEs in ARs using full-disk photospheric line-of-sight magnetogram data taken by the Helioseismic and Magnetic Imager (HMI) onboard the SDO.

• 천문학회보
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• 제37권2호
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• pp.72.2-72.2
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• 2012

We analyzed the properties of shock waves in galaxy clusters, by using the data of simulations for the large-scale structure of the universe with the spatial resolution of up to 25 kpc/h. In a substantial fraction of clusters, we found that strong shocks with Mach number of several or larger exist in outskirts within the virial radius. They are produced by the accretion of warm gas flowing from filaments to clusters, and generate large cosmic-ray fluxes. The cosmic rays advect into cluster cores, but may temporally induce the population inversion, that is, larger population at larger radius, suggested by recent radio and ${\gamma}$-ray observations.

• 센서학회지
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• 제24권2호
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• pp.96-100
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• 2015

In the present study, we developed a real-time radiation-monitoring sensor for an underwater radiation-monitoring system and evaluated its effectiveness using reference radiation sources. The monitoring sensor was designed and miniaturized using a silicon photomultiplier (SiPM) and a cerium-doped-gadolinium-aluminum-gallium-garnet (Ce:GAGG) scintillator, and an underwater wireless monitoring system was implemented by employing a remote Bluetooth communication module. An acrylic water tank and reference radiation sources ($^{137}Cs$, $^{90}Sr$) were used to evaluate the effectiveness of the monitoring sensor. The underwater monitoring sensor's detection response and efficiency for gamma rays and beta particles as well as the linearity of the response according to the gammaray intensity were verified through an evaluation. This evaluation is expected to contribute to the development of base technology for an underwater radiation-monitoring system.