• Nuclear Engineering and Technology
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• v.56 no.5
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• pp.1754-1761
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• 2024

In hadrontherapy, secondary fragments are generated by nuclear interactions of the incident heavy ion beam with the atomic nuclei of the target. It is important to determine the yield of production and the dose contribution of these secondary fragments in order to determine the radiobiological effectiveness more accurately. This work aims to fully identify the secondary fragments generated by nuclear interactions of proton and helium (⁴He) ion beams in a High-Density Polyethylene (HDPE) target and to investigate the dose contributions by secondary fragments. Incident protons with energies of 55.90 MeV and 105.20 MeV and helium ions with energies of 52.55 MeV/u and 103.50 MeV/u in the HDPE phantom have been investigated by the means of Geant4 Monte Carlo (MC) simulations. Simulated results were validated using NASA Space Radiation Laboratory (NSRL) Bragg curves experimental data. The results showed that the dose contribution of secondary fragments deriving from helium ion beams is three times higher than in the case of proton beams. This is due to a higher production of nuclear fragments in the case of helium ion beams. This work contributes to a better understanding of secondary fragments generated by protons and helium ions in the HDPE target.

• Journal of Astronomy and Space Sciences
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• v.31 no.1
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• pp.73-81
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• 2014

A package of space science instruments, dubbed the Instruments for the Study of Space Storms (ISSS), is proposed for the Next Generation Small Satellite-1 (NEXTSat-1), which is scheduled for launch in May 2016. This paper describes the instrument designs and science missions of the ISSS. The ISSS configuration in NEXTSat-1 is as follows: the space radiation monitoring instruments consist of medium energy particle detector (MEPD) and high energy particle detector (HEPD); the space plasma instruments consist of a Langmuir probe (LP), a retarding potential analyzer (RPA), and an ion drift meter (IDM). The space radiation monitoring instruments (MEPD and HEPD) measure electrons and protons in parallel and perpendicular directions to the geomagnetic field in the sub-auroral region, and they have a minimum time resolution of 50 msec for locating the region of the particle interactions with whistler mode waves and electromagnetic ion cyclotron (EMIC) waves. The MEPD measures electrons and protons with energies of tens of keV to ~400 keV, and the HEPD measures electrons with energies of ~100 keV to > ~1 MeV and protons with energies of ~10 MeV. The space plasma instruments (LP, RPA, and IDM) observe irregularities in the low altitude ionosphere, and the results will be compared with the scintillations of the GPS signals. In particular, the LP is designed to have a sampling rate of 50 Hz in order to detect these small-scale irregularities.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.1
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• pp.38-49
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• 1985

The water soluble organic fractions (WSOF) from an agricultural soil (W), a soil treated with sludge for 6 years ($WS_6$), a sludge-soil mixture incubated for one week ($WS_1$), and sewage sludge (SS) were extracted, purified, and characterized by elemental analysis, functional group determinations, infrared, UV-visible, and proton nuclear magnetic resonance spectrosocpy. The SS was characterized by higher organic H, N, and P contents, a higher H/C ratio, and a lower C/N ratio than W. Total acidity carboxyl and phenolic hydroxyl group contents were generally highest in SS, intermediate in $WS_6$ and $WS_1$, and lowest in W. Overall aromatic character and aromatic carboxyl group contents were highest in W, and lowest in SS. Aliphatic proton, aliphatic carboxyl, and phenolic hydroxyl group contents were highest in SS, and lowest in W. Protein decomposition products were the pronounced components in SS, and decreased in concentration as the sludge component in the mixtures decreased. The $^1H$-NMR spectra suggested that the SS-protons were bound to a wider range of functional groups than W-protons. Structural complexities around the aromatic protons followed the following order: SS>$WS_1$>$WS_6$>W.

• Journal of Astronomy and Space Sciences
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• v.22 no.4
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• pp.441-450
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• 2005

The organic material is one of the most popular material for the satellites and the spacecrafts in order to perform the thermal management, and to protect direct exposure from the space environment. The present paper observes material property changes of organic material under the space environment by using ground facilities. One of the representative organic thermal management material of satellites, 2 mil ITO(Indium Tin Oxide) coated aluminized KAPTON was selected for experiments. In order to investigate the single parametric effect of protons in space environment, MC-50 cyclotron system in KIRAMS(Korea Institute of Radiological and Medical Science) was utilized for the ion beam irradiation of protons and ion beam dose was set to the Very Large August 1972 EVENT model, the highest protons occurrence near the earth orbit in history. The energy of ion beam is fixed to 30MeV(mesa electron volt), observed average energy, and the equivalent irradiance time conditions were set to 1-year, 3-year, 5-year and 10-year exposure in space. The procedure of analyses includes the measurement of the ultimate tensile strength for the assessment of quantitative degradation in material properties, and the imaging analyses of crystalline transformation and damages on the exposed surface by FE-SEM(Field Emission Scanning Electron Spectroscopy) etc.

• The Korean Journal of Food And Nutrition
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• v.27 no.3
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• pp.532-537
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• 2014

Cortex Phellodendri (CP) is derived from the dried bark of Phellodendron amurense. It has been widely used as a drug in traditional Korea medicine for treating diarrhea, jaundice, swelling pains in the knees and feet, urinary tract infections, and infections of the body surface. Many analytical methods have been used to study oriental herbal medicines, such as thin-layer chromatography, column liquid chromatography, and high performance liquid chromatography (HPLC). In this study, preparative centrifugal partition chromatography (CPC) was successfully carried out in order to separate pure compounds from a CP methanol extract. The optimum two-phase CPC solvent system was composed of n-butanol: acetic acid: water (4:1:5 v/v/v). The flow rate of the mobile phase was 3 mL/min in ascending mode with rotation at 1,000 rpm. The CPC-separated fraction and purification procedures were carried out by preparatory HPLC. The $^1H$ NMR spectrum revealed that the resonances at ${\delta}$ 4.10 and 4.20 ppm corresponded to three protons ($-OCH_3$), whereas those at ${\delta}$ 6.10 ppm corresponded to two protons ($-OCH_2O-$). Further, two aromatic protons (H-11 and H-12) conveys a doublet-doublet pattern. The H-11 doublet and H-12 doublet appear at ${\delta}$ 7.98 and 8.11, respectively. The $^{13}C$ NMR. spectrum showed a tetrasubstituted with a methylenedioxy group at C2 and C3, and two methoxy groups at C9 and C10. The chemical structure of the berberine was identified by $^1H$, $^{13}C$-nuclear magnetic resonance and electrospray ionization-mass spectroscopy spectral data analysis.

• Journal of radiological science and technology
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• v.44 no.4
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• pp.359-365
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• 2021

A heavy particle accelerator is a device that accelerates particles using high energy and is used in various fields such as medical and industrial fields as well as research. However, secondary neutrons and particle fragments are generated by the high-energy particle beam, and among them, the neutrons do not have an electric charge and directly interact with the nucleus to cause radiation of the material. Quantitative evaluation of the radioactive material produced in this way is necessary, but there are many difficulties in actual measurement during or after operation. Therefore, this study compared and evaluated the generated radioactive material in the concrete shield for protons and carbon ions of specific energy by using the simulation code FLUKA. For the evaluation of each energy of proton beam and carbon ion, the reliability of the source term was secured within 2% of the relative error with the data of the NASA Space Radiation Laboratory(NSRL), which is an internationally standardized data. In the evaluation, carbon ions exhibited higher neutron flux than protons. Afterwards, in the evaluation of radioactive materials under actual operating conditions for disposal, a large amount of short-lived beta-decay nuclides occurred immediately after the operation was terminated, and in the case of protons with a high beam speed, more radioactive products were generated than carbon ions. At this time, radionuclides of ⁴⁴Sc, ³H and ²²Na were observed at a high rate. In addition, as the cooling time elapsed, the ratio of long-lived nuclides increased. For nonparticulate radionuclides, ³H, ²²Na, and for particulate radionuclides, ⁴⁴Ti, ⁵⁵Fe, ⁶⁰Co, ¹⁵²Eu, and ¹⁵⁴Eu nuclides showed a high ratio. In this study, it is judged that it is possible to use the particle accelerator as basic data for facility maintenance, repair and dismantling through the prediction of radioactive materials in concrete according to the cooling time after operation and termination of operation.

• Bulletin of the Korean Space Science Society
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• 2004.04a
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• pp.47-47
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• 2004

사이클로트론 가속기를 이용한 양성자 우주환경의 모사시험이 수행되었다. 모사시험에 사용된 사이클로트론은 양성자를 약 106-108protons/$\textrm{cm}^2$/s의 선속에서 200MeV까지 가속할 수 있다. 가속된 양성자는 우주에서 사용될 전자 소자에 입사되었으며, 양성자 조사에 의한 소자의 누적 반응과 순간 반응이 모두 관찰되었다. 주된 순간 반응은 저장된 데이터의 변화였으나, 간헐적인 기능 정지 현상도 관찰되었다. 누적 반응은 소자 내에서 소모되는 전류의 증가로 나타났다. (중략)

• ETRI Journal
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• v.29 no.1
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• pp.124-126
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• 2007

In this letter, we study the impact of single event upsets (SEUs) in space or defense electronic systems which use memory devices such as EEPROM, and SRAM. We built a microcontroller test board to measure the effects of protons on electronic devices at various radiation levels. We tested radiation hardening at beam current, and energy levels, measured the phenomenon of SEUs, and addressed possible reasons for SEUs.

• Journal of the Korean Ceramic Society
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• v.23 no.4
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• pp.85-89
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• 1986

Electrical conductivity have been measured as function of temperature in MgO.$P_2O_5$ glasses containing small amounts of water. Conduction was due to the contribution of $H^+$ and the mobility of protons in the glass increased linearly with increasing its concentration. The conductivity was pro-portional to the square of the proton concentration and the activation energy decreased linerly with increasing logarithm of the proton concentration, And $$\sigma$_0$ and $A_0$ was independent of the proton concentration but not on glass compositions.

• YAKHAK HOEJI
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• v.39 no.2
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• pp.205-209
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• 1995

Methylene protons of benzyl and ethyl ester in ethyl 1-benzyl-2, 3-dioxo-cyclopenta[b]-pyrrole-3a-carboxylate (A) exhibited opposite$^{1}$H-NMR spectral patterns mutually between magnetic equivalence and nonequivalence depending on concentration and temperature. The diastereotopic spectral data of compound A were reported with brief interpretation.