• Progress in Medical Physics
• /
• v.28 no.4
• /
• pp.226-231
• /
• 2017

The aim is to investigate the spectra responsibilities of QD (Quantum Dot) for the innovation of new dosimetry application for therapeutic Megavoltage X-ray range. The unique electrical and optical properties of QD are expected to make it a good sensing material for dosimeter. This study shows the spectra responsibility of toluene based ZnCd QD and PPO (2.5-diphenyloxazol) mixed liquid scintillator. The QDs of 4 sizes corresponding to an emission wavelength (ZnCdSe/ZnS:$440{\pm}5nm$, ZnCdSeS:470, 500, $570{\pm}5nm$) were utilized. A liquid scintillator for control sample was made of toluene, PPO. The Composition of QD loaded scintillators are about 99 wt% Toluene as solvent, 1 wt% of PPO as primary scintillator and 0.05, 0.1, 0.2 and 0.4 wt% of QDs as solute. For the spectra responsibility of QD scintillation, they were irradiated for 30 second with 6 MV beam from a LINAC ($Infinity^{TM}$, Elekta). With the guidance of 1.0 mm core diameter optical fiber, scintillation spectrums were measured by a compact CCD spectrometer which could measure 200~1,000 nm wavelength range (CCS200, Thorlabs). We measured the spectra responsibilities of QD loaded organic liquid scintillators in two scintillation mechanisms. First was the direct transfer and second was using wave shifter. The emission peaks from the direct transfer were measured to be much smaller luminescent intensity than based on the wavelength shift from the PPO to QDs. The emission peak was shifted from PPO emission wavelength 380 nm to each emission wavelength of loaded QD. In both mechanisms, 500 nm QD loaded samples were observed to radiate in the highest luminescence intensity. We observed the spectra responsibility of QD doped toluene based liquid scintillator in order to innovate QD dosimetry applicator. The liquid scintillator loading 0.2 wt% of 500 nm emission wavelength QD has most superior responsibility at 6 MV photon beam. In this study we observed the spectra responsibilities for therapeutic X-ray range. It would be the first step of innovating new radiation dosimetric methods for radiation treatment.

• Journal of Bio-Environment Control
• /
• v.24 no.3
• /
• pp.135-146
• /
• 2015

To provide the data necessary to determine the design wind speed for calculating the wind load acting on a greenhouse, we measured the wind speed below 10m height and analyzed the power law exponents at Buan and Gunwi. A wind speed greater than $5m{\cdot}s^{-1}$ is appropriate for calculating the power law exponent necessary to determine the wind speed distribution function according to height. We observed that the wind speed increased according to a power law function with increased height at Buan, showing a similar trend to the RDC and JGHA standards. Therefore, this result should be applied when determining the power law function for calculating the design wind speed of the greenhouse structure. The ordinary trend is that if terrain roughness increases the value of power law exponent also increases, but in the case of Gunwi the value of power law exponent was 0.06, which shows contrary value than that of the ordinary trend. This contrary trend was due to the elevations difference of 2m between tower installed and surrounding area, which cause contraction in streamline. The power law exponent started to decrease at 7 am, stopped decreasing and started to increase at 3 pm, and stopped increasing and remained constant at 12 pm at Buan. These changes correspond to the general change trends of the power law exponent. The calculated value of the shape parameter for Buan was 1.51, confirming that the wind characteristics at Buan, a reclaimed area near the coast, were similar to those of coastal areas in Jeju.

• The Korean Journal of Malacology
• /
• v.32 no.2
• /
• pp.103-109
• /
• 2016

The effect of different feeding rate on the growth and survival rate of 3-year-old abalone, Haliotis dicsus hannai were investigated in marine net cage culture. Feeding rate is determined that was fed 5, 10, 15 and 20 percentage to abalone at body weight once daily : 5 daily feeding rate (DFR), 10 DFR, 15 DFR and 20 DFR. After that, it was conducted to reared during thirteen month with two replicates in net cage culture. In the growth performance of reared abalone (initial mean shell length $73.77{\pm}11.27mm$) in net cage culture, that the absolute growth rate (ARG), daily growth rate (DGR) and specific growth rate (SGR) to the shell length and shell breadth, as well as weight gain (WG), daily weight gain (DWG) and specific weight gain (SWG) to body weight of 5 DFR were higher than those of different groups (P < 0.05). Also, survival rate of all feeding rate groups was not significant, but it was showed bellow 30 percents. Therefore, these results is showed that the daily feeding rate for natural feed of 3-year-old abalones reared in net cage culture should be to supply among five to ten percents.

• Korean Journal of Health Education and Promotion
• /
• v.26 no.1
• /
• pp.1-13
• /
• 2009

Objectives: This study was conducted to estimate the health-related quality of life (HRQOL) using EuroQoL-5 Dimension (EQ-5D) and to identify its related factors among urban-dwelling adults. Methods: The data for this study were obtained from 1,134 subjects aged $20\sim91$, who participated in 'Survey on the health status and demand for health' in two cities of Korea (Dong-gu, Gwangju and Suncheon-si, Jeollanamdo). The HRQOL was measured using the EQ-5D instrument and EQ-5D index scores were calculated by two Korean valuation study model using time trade-off method. Results: The mean EQ-5D index scores for all subjects were $0.865{\pm}0.218$ (model A), and $0.921{\pm}0.170$ (model B). The EQ-5D index score was significantly different according to demographic and socioeconomic characteristics (gender, age, marital status, education, occupation, income, and health security system), self-rated health condition, health-related psychological assessments (enough sleep, fatigue rate, stress rate, and degree of satisfaction on the residence). The results of multiple linear regression showed that age, marital status, income, coverage of medical insurance, self-rated health condition, and fatigue rate were significantly related common statistical factors of HRQOL in two Korean valuation study model. Conclusion: Among the adults residing in urban environment, the HRQOL was significantly lower on the subjects with following conditions: higher age, being alone without a spouse as a result of death, divorce or separation, low income, medical aid program, poor self-rated health condition, and chronic fatigue. In order to improve the urban adults' quality of life, healthcare policy and health promotion program must be developed with considerations to factors related to the HRQOL.

• Journal of Aquaculture
• /
• v.20 no.2
• /
• pp.90-95
• /
• 2007

Artificially-produced juvenile black sea bream, Acanthopagrus schlegeli (total length $10.4{\pm}1.1\;cm$, body weight $18.7{\pm}3.4\;g$) were released into the Gamak Bay in Korea. And their initial feeding habits and body compositions were compared with those of cultured fish (CUL) for a period of one month after release. The released black sea bream commenced feeding on the 1st day after release, and predation rate was more than 80% during the sampling period. The stomach content of fish was composed of mainly fishing bait and krill in fish sampled on 15th days after release; however, its content changed to the natural organisms such as algae and small crustaceans when the fish was sampled on 20th days after release. Crude lipid content of carcass of fish in the sampling station A (SA) were lower than that of fish in the initial, sampling station B (SB) and CUL for the 5th and 10th days after release. Carcass n-3 HUFA composition, total amino acid and essential amino acid contents of released fish showed high trend compared to that of cultured fish in 30th days after release. The released fish have the ability to adjust their feeding habits and biochemical metabolism to the natural environment within a short period even though they showed preference to artificial feed in the early days after release.

• Journal of Technologic Dentistry
• /
• v.34 no.2
• /
• pp.83-93
• /
• 2012

Purpose: The objective of this study is to find out physical properties and the flexural strength changed by the low temperature degradation of the block which is needed to make bio-prosthetic dentistry which is better than feldspar affiliated ceramic made by building up ceramic powder and also to apply this to the clinical use of zirconia monolithic all-ceramic crown. Methods: Flexural strength of each sample was evaluated before and after the Low Temperature Degradation, and physical properties of the Tetra Zirconia Block containing 3mol % was evaluated as well. The average and standard deviation of each experimental group were came out of the evaluation. Statistical package for social science 18.0 was used for statistics. Results: The average density of the monolithic all-ceramic crown was $6.0280{\pm}0.0147g/cm$, the relative density was 99.01 %. When the sample was sintered at $1480^{\circ}C$ the diameter of average particle was $396.62{\pm}33.71nm$. All the samples had no monolithic peak after XRD evaluation but only had tetragonal peak. There were statistically significant differences in the result of flexural strength of the samples evaluated after and before the low temperature degradation, the flexural strength before the low temperature degradation was $1747.40{\ss}{\acute{A}}$, at the temperature of $130^{\circ}C$ the flexural strength after the low temperature degradation was 1063.99MPa (p<0.001). There was statistically significant difference in the result of strength of 1020.07MPa after the low temperature degradation at the temperature of $200^{\circ}C$ (p<0.001). Conclusion: The block which was made for this evaluation possesses such an excellent strength among dental restorative materials that it is thought to have no problems to use for tetragonal zirconia polycrystal.

• Journal of the Korean Chemical Society
• /
• v.38 no.5
• /
• pp.339-344
• /
• 1994

The crystal structure of a methanol sorption complex of dehydrated partially Co(II)-exchanged zeolite A, $Co_4Na_4-A{\cdot}6.5CH_3OH$ (a = 12.169(1) $\AA)$, has been determined by single-crystal X-ray diffraction techniques in the cubic space group Pm$\bar3$m at $21(1)^{\circ}C. $Co_4Na_4$-A was dehydrated at $360^{\circ}C\;and\;2{\times}10^{-6}$ torr for 2 days, followed by exposure to about 104 torr of methanol vapor at $22(1)^{\circ}C$ for 1 hr. The structure was refined to final error indices, $R_1$ = 0.061 and $R_2$ = 0.060 with 147 reflections, for which I > $3\sigma(I).$ In this structure, four $Co^{2+}$ ions and 1.5 $Na^+$ ions per unit cell lie at 6-ring positions: the $Na^+$ ions are recessed 0.44 $\AA$ into the sodalite unit and the Co(II) ions extend ca. 0.55 $\AA$ into the large cavity. 2.5 $Na^+$ ions lie in an 8-oxygen ring plane. The 6.5 methanol molecules are sorbed per unit cell. The 6.5 methanol oxygens, all in the large cavity, associate with the 4 $Co^{2+}$ ions and 2.5 $Na^+$ ions.

• Korean Journal of Ichthyology
• /
• v.27 no.3
• /
• pp.189-198
• /
• 2015

This research has been launched in order to observe the osteological development of sevenband grouper, Epinephelus septemfasciatus larvae and juveniles and will be used for the basic data of phylogenetically systematics research. We got some samples of larvae and juveniles from a adult fish which belongs to the sea cage in Geomun-do, Yeosu-si, Jeolla-namdo province, and we have watched them. The average of breeding water temperature was $21.5{\sim}24.5^{\circ}C$ (average $23.0{\pm}1.5^{\circ}C$). In yolk-sac larvae just after hatching, ossification was not observed at all, and when the average total length reached 2.66 mm, the premaxillary and maxillary forming the upper jaw, dentary forming the lower jaw, and parasphenoid forming the skull base were ossified. In addition, the preopercle and opercle forming the opercular region began to be ossified. The caudal skeleton supporting the caudal fin is built with the caudal complex consisting of the malleus and incus. Until the average total length reached 2.59 mm, ossification did not occur at all and the urostyle bent at 45-degree angle. As to the ossification of the pterygiophore, when the average total length was 6.12 mm, the first interhemal spine began to be ossified in articulation with two spines of the anal fin, and the synapse also began to be ossified in articulation with two spines of the dorsal fin. When the average total length was 21.9 mm, individuals with completed ossification of the interhemal spines and synaptic clefts began to appear.

• Korean Journal of Food Science and Technology
• /
• v.41 no.3
• /
• pp.278-283
• /
• 2009

This study was carried out to evaluate the quality characteristics of white pan breads containing 0.5% of gums, including HPMC, MC and SA. Moisture content, water activity, cooling loss, bread volume, rheological, and sensory evaluations were performed to examine the bread quality characteristics. Moisture content and water activity were highest in the bread with added HPMC. HPMC showed the smallest cooling loss among the breads compared to the other added gums. The bread with added SA had the thelargest volume at $2,560{\pm}24$ mL. In terms of rheological properties, the hardness of the bread containing HPMC was lowest and the springness of the bread with added SA was the highest. In sensory evaluations, the bread containing HPMC was evaluated as the most preferred product by acquiring the highest scores in internal and external evaluations. Consequently, the bread containing 0.5% SA showed better volume and springiness values. However, the bread containing 0.5% HPMC showed greater moisture content, greater water activity, lower cooling loss, and better sensory evaluation scores. Based on the overall results, HPMC was considered to be the most effective hydrocolloid to increase bread quality.

• Journal of Korean Society for Atmospheric Environment
• /
• v.22 no.5
• /
• pp.590-603
• /
• 2006

Size-and time-resolved aerosol samples were collected using an eight-stage Davis rotating unit for monitoring (DRUM) sampler from 23 March to 29 April 2001 at Gosan, Jeju Island, Korea, which is one of the super sites of Asia-Pacific Regional Aerosol Characterization Experiment(ACE-Asia). These samples were analyzed using synchrotron X-ray fluorescence for 3-hr average concentrations of 19 elements including Al, Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, and Pb. The size-resolved data sets were then analyzed using the positive matrix factorization(PMF) technique to identify possible sources and estimate their contributions to particulate matter mass. PMF analysis uses the uncertainty of the measured data to provide an optimal weighting. Twelve sources were resolved in eight size ranges($0.09{\sim}12{\mu}m$) and included continental soil, local soil, sea salt, biomass/biofuel burning, coal combustion, oil combustion, municipal incineration, nonferrous metal source, ferrous metal source, gasoline vehicle, diesel vehicle, and volcanic emission. The PMF result of size-resolved source contributions showed that natural sources represented by local soil, sea salt, continental soil, and volcanic emission contributed about 79% to the predicted primary particulate matter(PM) mass in the coarse size range ($1.15{\sim}12{\mu}m$) while anthropogenic sources such as coal combustion and biomass/biofuel burning contributed about 58% in the fine size range($0.56{\sim}2.5{\mu}m$). The diesel vehicle source contributed mostly in ultra-fine size range($0.09{\sim}0.56{\mu}m$) and was responsible for about 56% of the primary PM mass.