• Journal of Radiation Industry
• /
• v.5 no.3
• /
• pp.211-220
• /
• 2011

This study was carried out to develop salt tolerant varities of rapeseed (Brassica napus L.) which can be grown in the high salty reclaimed land. The seeds of three varieties 'Naehan', 'Tammi', and 'Halla' were treated by proton ion beams and gamma rays with 0 to 2,000 Gy. For the selection of salt tolerant lines, emergence and survival rate, and growth characteristics of $M_2$ to $M_4$ generations were investigated in the Saemangeum reclaimed fields with the different salt concentrations. The lines with potential salt tolerance were selected in the $M_4$ generation and tested indoor for their growth characteristics. There was no significant changes in the soil pH for $M_4$ generation during growth period. However, soil EC was higher in early spring than sowing period (mid October). In $M_4$ generation test, the seeds of original and selected line showed high rates of emergence and survival, as determined one month after sowing. After wintering, however, the original varieties showed the significant reduction in the survival rate, while the selected lines showed a higher survival rate and good growth, leading to the completion of their life cycle. Consequently we selected 9 lines from $M_4$ generation with better performance in growth and yield. Soil EC was $2.8{\sim}4.3dS{\cdot}m^{-1}$ during $M_4$ generation growth period. The laboratory test of the lines selected from $M_4$ generation was made for their salt tolerance potential. The selected lines showed higher chlorophyll and proline contents than the original varieties. There was also no significant difference in the emergence rate of seed between the original and selected varieties. In 200 mM natural sea salt, the $N{\gamma}600-21-1-641$ line derived from 'Naehan' was the highest in growth rate, leaf chlorophyll and proline contents. $T{\gamma}800-20-2-461$ line derived from 'Tammi' didn't show significant difference in growth rate compared to original variety in 200 mM and withered in 250 mM like other lines as time passed. $H{\gamma}200-7-1-740$ line showed similar growth and chlorophyll content compared to its original variety.

• The Korean Journal of Nuclear Medicine
• /
• v.25 no.2
• /
• pp.286-293
• /
• 1991

$^{123}I$, which is applied for the thyroid and other in vivo kinetic study, has a special role in life sciences. The 159 KeV $\gamma-ray$ from $^{123}I$ is almost ideally appropriate for the current imaging instrumentation. Its decay mode (electron capture) and short half-life (13.3 hr) reduced the burden of radiation dose to the patients, and its chemical property makes it easy to synthesize the labelling compounds. In this experiment, the production of $^{123}I$ via the nuclear reaction $^{124}Te(p,2n)^{123}I$ with 28 MeV protons was sutdied. $TeO_2$ is used as a target material, because it has good physical properties. The target was prepared with $TeO_2$ powder and was molten into a ellipsoidal cavity (a=14 mm, b=10 mm, $270.8mg/cm^2$ thick) of pure platinum. The irradiation was carried out in the external proton beam with incident energies range from 28 MeV to 22 MeV, and current was $30{\mu}A$. The loss of $TeO_2$ target was significantly reduced by using $4\pi-cooling$ system in irradiation. The dry distillation method was adopted for the separation of $^{123}I$ from irradiated target, and when it was kept 5 minutes at $780^{\circ}C$, its result was quantitative. The loss of the target material $(TeO_2)$ was below 0.2% for each production run and $^{123}I$ from the dry distillation apparatus was captured with 0.01 N NaOH in $Na^{123}I$ form, then the pH of the solution was adjusted to $7.5\sim9.0$ with HC1/NaOH. The $Na^{123}I$ solution was passed through $0.2{\mu}m$ membrane filter, and sterilized under high pressure and temperature for 30 minutes. The production of $^{123}I$ is acceptable for clinical application based on the quality of USP XXI.

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

• Journal of the Korean Chemical Society
• /
• v.41 no.12
• /
• pp.645-652
• /
• 1997

Hydride complexes Cp*Ru(CO)(PR3)H (Cp*=η5-C5Me5, PR3=PMe3, PEt3, PMePh2, PPh3, PCy3)(4a-4f) were synthesized by the reaction of the corresponding chloro complex Cp*Ru(CO)(PR3)Cl (3a-3f) with various hydridic reagent (NaBH4, LiAlH4, LiBEt3H) or NaOMe. Irradiation of Cp*Ru(CO)(PCy3)H (5e) in C6D6 solution with UV light caused H/D exchange reaction between coordinated Cp*, PCy3 and/or Ru-H ligand proton and a deuterium of the deuterated aromatic solvent through a series of inter- and intramolecular C-H activation. The proposed mechanism was described.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.34 no.11
• /
• pp.84-91
• /
• 2006

Recently, all the electrical parts for satellite application are required more strong against cosmic rays, because spacecraft's life time and function are depending on the their conditions. Also, a TID effect test was undertaken with units and/or subsystems which are already assembled on the PCB in past time. However, it is very hard to know and analyze that some abnormal states are appeared after launch. Moreover, it is necessary to perform a test of TID effects based on the parts level for preparing preliminary data in cosmic rays. Therefore, this paper presents a test-bed to perform a TID effect test of Metal-Oxide Semiconductor Field Effect Transistor (MOSFET) which is a fundamental element for electronics.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.42 no.8
• /
• pp.629-639
• /
• 2014

This paper deals with an alternative multi-functional structures by using grid-stiffened composite structure with excellent bending stiffness and lightweight characteristics which is capable of easy embedding of electrical/electronic circuitry into structure. The enhancement of thermal conduction capability is made by the application of pitch-based carbon fiber. The lightweight radiation spot shielding technique is also proposed for multi-functional structures without conventional housing and the effectiveness of selective radiation shielding is validated through the proton irradiation test.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.39 no.12
• /
• pp.1174-1180
• /
• 2011

Field Programmable Gate Array(FPGA)s are replacing traditional integrated circuits for space applications due to their lower development cost as well as reconfigurability. However, they are very sensitive to single event upset (SEU) caused by space radiation environment. In order to mitigate the SEU, on-board computer of STSAT-3 employed a triple modular redundancy(TMR) and scrubbing scheme. Experimental results showed that upset threshold energy was improved from 10.6 MeV to 20.3 MeV when the TMR and the scrubbing were applied to the on-board computer. Combining the experimental results with the orbit simulation results, calculated bit-flip rate of on-board computer is 1.23 bit-flips/day assuming in the worst case of STSAT-3 orbit.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2014.10a
• /
• pp.693-695
• /
• 2014

Radioactive isotopes for radiation diagnosis is production by using Cyclotron like a PET. Radioactive isotopes is influenced product yield according to shape and size of the proton beam and target irradiation position by cyclotron. And to develop a device for measuring the distribution of the beam to increase the loss of the beam. Beam measuring device is measured vertically beam current according move the two wires. In this way, by using the beam current value in each position you are able to know the cross section and location information of the beam. By scanning cross-section for X-axis Y-axis of beam acquires data of beam. Print this into 2D graph, and analyze the result. You can save this result by documentation process.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2022.09a
• /
• pp.86-86
• /
• 2022

Sorghum (Sorghum bicolor) is increasingly important as a biomass crop worldwide. Its genetic diversity provides a large range of biochemical composition suitable for various uses as bioplastics. Phenolic compounds are the main compounds of lignocellulosic residues, which can be used as a source of active components for their use in active packaging materials. In this research, we investigated the total phenolic content (TPC) and the total flavonoid content (TFC) among 60 mutant lines (early heading, high biomass and dwarfness) and their original cultivars. Sixty sorghum mutant lines were developed by treatment with gamma-ray or proton irradiation in 14 sorghum cultivars. The levels of TPC and TFC of 14 original cultivars were ranging from 3.27 to 11.54 mg/100 g and 2.39 to 6.74 mg/100 g, respectively. The TPCs of the mutant lines were ranging from 1.92 to 13.10 mg/100 g with average content of 6.35 mg/100 g. The TFCs of the mutant lines were ranging from 1.72 to 8.30 mg/100 g with average content of 4.20 mg/100 g. Three mutant lines derived from gamma-ray showed significant lower TPC and TFC than those of the original cultivar. While, five mutant lines showed significant higher TPC and TFC. These findings will be useful for the selection of sorghum genotypes with improved phenolic compounds.

• Journal of the Korean Society of Radiology
• /
• v.7 no.3
• /
• pp.213-219
• /
• 2013

Currently, about 35 cyclotrons have been operating in South Korea. Most of them are mainly used for the synthesis of radiopharmaceuticals such as $^{18}FDG$, which is a cancer tracer for nuclear medicine. Highly enriched $H_2{^{18}}O$ containing up to 98% of $^{18}O/O$ isotope ratio is used as the target for $^{18}F$ production. The price of the highly enriched $H_2{^{18}}O$ ranges 60~70 USD/g, and all of them have been imported from foreign country in spite of the very expensive price. The target (enriched $H_2{^{18}}O$) is non-radioactive before the proton beam irradiation. But, the post-irradiation target (used $H_2{^{18}}O$) must be managed following the National Radiation Safety Regulations, because it turns into radioactive by the radioactivation of the impurities within the target. Recently, nevertheless of the fast increasing amount of used $H_2{^{18}}O$ in accordance with the increasing number of nuclear medicine cases, any activation analysis on the used $H_2{^{18}}O$ have been conducted yet in Korea. In this research, activation analysis have been conducted to confirm the specific radioactivity(Bq/g) of each radioisotopes within the used $H_2{^{18}}O$. The analysis have been done on the 3 of 20g samples collected from the used $H_2{^{18}}O$ storages at different cyclotron centers. Based on the results, it was confirmed that the "used $H_2{^{18}}O$" contains gamma emitters such as $^{56}Co$, $^{57}Co$, $^{58}Co$, and $^{54}Mn$ as well as the considerable amount of beta emitter $^3H$. It was also confirmed that the only one sample contained over exemption level of gamma emitters while the specific activity of tritium was lower than the exemption level in all samples. The specific activity of radioisotopes were measured different levels in the samples depending on the elapsed time after irradiation. Further study on the activation of the "used $H_2{^{18}}O$" is definitely necessary, nevertheless the as-is results of this research must be useful in establishing a rational "used $H_2{^{18}}O$" management protocol.