• Journal of radiological science and technology
• /
• v.46 no.6
• /
• pp.509-517
• /
• 2023

This study analyzed imaging conditions and exposure index through clinical information collection and dose calculation programs in coronary angiography examinations. Through this, we aim to analyze the effective dose according to examination conditions and provide basic data for dose optimization. In this study, ALARA(As Low As Reasonably Achievable)-F(Fluoroscopy), a program for evaluating the radiation dose of patients and the collected clinical data, was used. First, analysis of imaging conditions and exposure index was performed based on the data of the dose report generated after coronary angiography. Second, after evaluating organ dose according to 9 imaging directions during coronary angiography, with the LAO fixed at 30°, dose evaluation was performed according to tube voltage, tube current, number of frames, focus-skin distance, and field size. Third, the effective dose for each organ was calculated according to the tissue weighting factors presented in ICRP(International Commission on Radiological Protection) recommendations. As a result, the average sum of air kerma during coronary angiography was evaluated as 234.0±112.1 mGy, the dose-area product was 25.9±13.0 Gy·cm², and the total fluoroscopy time was 2.5±2.0 min. Also, the organ dose tended to increase as the tube voltage, milliampere-second, number of frames, and irradiation range increased, whereas the organ dose decreased as the FSD increased. Therefore, medical radiation exposure to patients can be reduced by selecting the optimal tube voltage and field size during coronary angiography, maximizing the focal-skin distance, using the lowest tube current possible, and reducing the number of frames.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.30 no.3 s.47
• /
• pp.369-375
• /
• 2004

In this study, liquid crystalline (LC) is formed using Gemini surfactant (GS) type and moisturizing effect in vivo is measured. $3.0\;wt\%$ of sodium dicocoyl ethylene diamine (PEG)-15 sulfate (SCD-PEG-15S) is used as GS and $4.0\;wt\%$ of hydrogenated dimer acid esters (HDAE) as booster. For stabilizers, $2.0\;wt\%$ of behenyl alcohol (BA) and $1.0\;wt\%$ of Iyso-lecithin (LyL) are utilized. It is stabilized in pH from 4.0 to 10.5 and the best condition is in pH 6.5. The value of viscosity is $8,000\pm500$ cP. The most excellent particles are formed within the range of 4.0 to 15.5 um. Formed LC is observed around LC particles using polarization microscope. It is also observed that lamellar gel network structure is formed around LC particles. Moisturizing effect is improved by $13.6\%$ (P<0.05) compared to control when measured 30 min later after coating samples. After 1 h, moisturizing effect is improved by 1$12.6\%$ (P<0.05) than control while showing $28.3\%$ (P<0.05) of improvement after 4 h. These results may be caused from that manufactured LC forms lamellar structure so that it has better water-holding ability and absorbance of oil increases. This formula could be utilized by delivery system (DS) on skin so that this technology can be applied for manufactuing pharmaceuticals and cosmetics.

• Investigative Magnetic Resonance Imaging
• /
• v.16 no.1
• /
• pp.16-24
• /
• 2012

Purpose : The purpose of this study was to determine whether there is a significant correlation between vertebral marrow fat fraction measured using Dixon quantitative chemical shift MRI (QCSI) and BMD on dual-energy X-ray absorptiometry (DXA). Materials and Methods: This retrospective study included 68 healthy individuals [mean age, 50.7 years; range, 25-76; male/female (M/F) = 36/32] who underwent DXA of the L-spine and whole body MRI including QCSI of the L-spine and chemical shift MRI of the liver. The enrolled individuals were divided into subgroups according to sex and T-score [i.e., normal bone density (M/F=27/23) and osteopenia (M/F=9/9)]. Vertebral marrow (Dixon QCSI, TR/TE 10.2/4.8 ms) and hepatic fat fractions (chemical shift technique, TR/TE 110/4.9 and 2.2 ms) were calculated on MRI. We evaluated whether there were significant differences in age, body mass index (BMI), vertebral marrow fat fraction, or hepatic fat fraction among the subgroups. Whether or not the participant had reached menopause was also evaluated in females. The correlations among variables (i.e., age, BMI, vertebral marrow and hepatic fat fractions, BMD) were evaluated using Spearman's correlation method. Results: There were no significant differences in age, BMI, or vertebral marrow and hepatic fat fractions between the two male subgroups (normal bone density vs. osteopenia). In female subjects, mean age in the osteopenic subgroup was greater than that in the normal subgroup (p=0.01). Presence of menopause was more common in the osteopenic subgroup [77.8% (7/9)] than the normal subgroup [26.1% (6/23), p<0.05]. The other variables showed no significant difference between female subgroups. The only significant correlation with marrow fat fraction after partial correlation analysis was that with age in the female subjects (r=0.43, p<0.05). Conclusion: The vertebral marrow fat fraction calculated using the Dixon QCSI does not precisely reflect the mild decrease in BMD for either sex.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.65 no.3
• /
• pp.222-230
• /
• 2020

Maize grain quality can be improved by raising lysine content, which is an essential amino acid present in insufficient quantities in normal maize. Maize varieties with such modifications are known as quality protein maize (QPM). To date, no Korean maize cultivars contain high amounts of lysine. To introduce quality protein maize to Korean cultivars, we crossed QPM CIMMYT maize lines (CML) with KS140, an elite inbred line used as a parent of several cultivars such as 'Gangdaok' and 'Pyeonganok'. We analyzed the phenotypic characteristics of F₁ plants as well as the protein contents, amino acids, and fatty acids profiles of the self-pollinated seeds of the F₁ hybrids, and evaluated the feasibility of CML as a source of QPM. Days to anthesis of the CML ranged from 78 to 90 days after planting (DAP), whereas a range of 81~87 was recorded for F₁ hybrids. The average days to anthesis was 85 for KS140, CML, and the F₁ hybrids. The protein content of the CML was measured to be between 9.1 and 12.1%, with the highest and lowest values being recorded in CML153 and 191, respectively. The F₁ hybrids had protein contents of 9.1~11.1%, and the highest content was observed in KS141/CML188. The fatty acids profiles were very similar across all analyzed maize samples, and linoleic acid (C18:2) composed the greatest proportion. Glutamic acid made up the largest proportion of amino acids in all maize samples. Lysine composition was highest in CML155 (6.92% of all amino acids), with an average composition of 4.83% across the CML. In contrast, KS140 showed a lysine content of 2.51%. In F₁ hybrids, the average lysine composition was 3.46%, and KS140/CML164 (4.18%) and KS140/CML163 (4.99%) contained more lysine than either parent. Taken together, these results indicate that CML could become promising QPM sources to improve grain quality in Korean maize cultivars.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.18 no.7
• /
• pp.774-783
• /
• 2007

This paper presents an integrated packaging antenna-diplexer module for wireless communication systems in the Cellular and SDMB band. The design and the realization of the proposed one are experimentally analyzed and discussed. It consists of a dual-resonance antenna and a diplexer with a multi-layer LTCC(${\varepsilon}_r=7.8,\;tan\;{\delta}=0.0043$) technology with integration capability and low loss. The dual-resonance antenna of the proposed module has the meander line structure for size reduction and has the shorting structure of an inverted F antenna to achieve good impedance matching. The diplexer of the proposed module was designed with the combination of low pass filter(LPF) and high pass filter(HPF). Decreasing the mutual interference between them provides a high isolation characteristic. The proposed antenna-diplexer module with dimensions of $27.5{\times}12.0{\times}2.2mm$ operates within a range from 813 MHz to 902 MHz for the cellular band and from 2,586 MHz to 2,655 MHz for the SDMB band. And the measured gain of the fabricated module is -1.96 dBi for Cellular band and -5.43 dBi for SDMB band. The parameters for the antenna-diplexer module are investigated and the several performances are discussed.

• Economic and Environmental Geology
• /
• v.45 no.1
• /
• pp.23-30
• /
• 2012

Major ions and nitrogen isotopic analyses were performed to determine the geochemical characters and to identify the source of nitrate of the shallow groundwater around agricultural field in the Youngdong area. The pH value of groundwater ranges from 60. to 8.2 (pH 7.2, mean). The average of EC, Eh and DO is 369 ${\mu}S/cm$ (70~729 ${\mu}S/cm$), 165.6 mV (29~383.2 mV), 4.3 mg/L (1.8~8.0 mg/L) respectively. The ion concentraion of groundwater was in the order of $Ca^{2+}$>$Na^{2+}$>$Mg^{2+}$>$K^{2+}$ and ${HCO_3}^-$>${NO_3}^-$>${SO_4}^{2-}$>$Cl^-$>$F^-$. Most of groundwater is Ca-$HCO_3$ type. The groundwater was affected by water-rock interaction in the shallow depth. Some groundwater is Ca-Cl or Na-$HCO_3$ (2.5%) type that was due to agricultural activities. The $NO_3$_N concetration of grondwater range from 10.2 mg/l to 26.9 mg/l, which show that this area is under nitrate pollution. ${\delta}^{15}N-NO_3$ value of the groundwater is the origins of are a combination of animal wastes and man-made fertilizers.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.21 no.6
• /
• pp.323-330
• /
• 1988

The spatial distribution of sea water temperature variation pattern in the South-eastern coastal region of Korea was studied by empirical orthogonal function (E. O. F) analysis in several depths from surface to 300m using the monthly mean water temperature averaged for 23 years, water mass analysis by T. S diagram and sectional diagram of water temperature. Typical type of water temperature variation in this area can be divided into surface (0m-50m), subsurface (100m-150m) and intermediate (200m-300m) layer. The first mode value of water temperature change on the surface layer showed $99\%$ of total variation, and decreased with the increase of the depth. It is deduced to be in the range of $60-70\%$ on the 300m layer. The representative type of water temperature fluctuation by the first mode in each layer is as follows. Water temperature change in the surface layer showed a seasonal variation. In the subsurface layer, it is governed by the interaction of the Tsushima Warm Current water with the cold water and by the heat transfer process from the upper layer. In the intermediate layer, water temperature variation seems to be governed by the advection of the bottom cold water.

• Analytical Science and Technology
• /
• v.15 no.4
• /
• pp.329-334
• /
• 2002

Tributyl phosphate(TBP) is used in solvent extraction process for radioactive waste. This compound may be degraded to dibutyl phosphate($DBP^-$), monobutyl phosphate($MBP^{2-}$) and ${PO_4}^{3-}$ by radioactive material. Amount of $DBP^-$ and $MBP^{2-}$ in TBP must be monitored because they production of these compounds means degradation of which leads to a decrease in the extraction yield. Retention behavior for $DBP^-$, $MBP^{2-}$, $F^-$, $Cl^-$, ${NO_2}^-$, ${NO_3}^-$, ${SO_4}^{2-}$ and ${PO_4}^{3-}$ are studied with AS4A-SC(Dionex) analytical column and $Na_2CO_3$/NaOH eluent by Ion chromatography. Optimum condition for these anions is 2 mM $Na_2CO_3$/1 mM NaOH eluent. All anions by this condition is well separated within 15min. Dynamic range is $10{\mu}g/mL$ - $100{\mu}g/mL$ for DBP and $5{\mu}g/mL$ - $50{\mu}g/mL$ for $MBP^{2-}$, respectively. The Detection limit for AS4A-SC are $1{\mu}g/mL$ for $DBP^-$ and $0.5{\mu}g/mL$ for $MBP^{2-}$ in this system with a $25{\mu}L$ sample loop.

• Journal of the Korean Wood Science and Technology
• /
• v.37 no.1
• /
• pp.56-64
• /
• 2009

The purpose of this study was to investigate and develop an eco-friendly wood adhesive based on vegetable oil (especially soybean oil), the renewable and sustainable natural resources, using ozonification technology for the chemical structure modification. The soybean oil (SBO) was reacted with $O_3$ at the rate of 7.13 g/h for different times, 15 minutes, 30 minutes, 60 minutes, and 120 minutes. The investigation of the modified chemical structure of the ozonized SBOs were conducted using FT-IR, $^1H$-NMR, MALDI-TOF MS, and GC/MS. As ozonification time increased, the peak of the unsaturated double bonds was disappeared and aldehyde or carboxyl peak appeared because ozonification broke the oil into small molecules. The plywoods were made at $110^{\circ}C$ with 30 seconds/mm hot-press time using the different ozonized SBO/pMDI adhesives and were tested for the dry, wet, cyclic boil test according to the Korea Industrial Standard F3101 Ordinary plywood. The bond strengths gradually increased with increasing ozonification time. The weight ratio 1:1 (ozonized SBO/pMDI), all strengths in 15, 30 and 60 minuets, exceeded constantly the dry, wet, cyclic boiling standard requirement. The range of ozonification time and weight ratio can fulfil1 the requirment of the wet test standard were 30~60 minutes and more than 0.5 pMDI. From the comprehensive view on the results of above experiments, it could be confirmed through experiments that ozonized SBO/pMDI has characteristics of effective reactivity and wet stability showed as an excellent candidate of wood adhesive applications.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.25 no.1
• /
• pp.209-224
• /
• 1998

The purpose of this study was to compare the amount of calcium fluoride deposited on the enamel and dentin surface and to obtain information on the morphological change and crystallographic details of mineral deposition after 12,000ppm APF application in vitro. The bovine enamel and dentin blocks were randomly assigned to eight groups according to artificial caries lesion formation and difference of fluoride application time. The fluoride concentration and morphological characteristics on the treated enamel and dentin surface were investigated by using fluoride quantitative analysis and SEM. The powdered enamel and dentin of the intact bovine incisors were prepared for the X-ray diffraction analysis. The following results were obtained. 1. The amounts of KOH-soluble fluoride on the carious enamel and dentin surface after 24h APF application were higher than after only 5min APF application(p<0.05), but in the case of the sound enamel and dentin surface were similar after 5min and 24h application (P>0.05). The fluoride content was highly increased in the carious dentin as compared with sound dentin after APF application(P<0.05). 2. The carious enamel surface after APF application, the demineralized enamel surface were recovered a more dense enamel surface and precipitation of crystal was observed a distintive surface layer of spherical globules of about 1 m diameter. In the case of the fluorided carious dentin surface, precipitation of calcium fluoride-like material was deposited both inside the dentinal tubules as well as in the intertubular regions. 3. The crystallographic structure of powdered enamel and dentin after 24h APF application had large crystallities of apatite and CaF2 diffraction peaks in the enamel as compared with dentin. The diffraction data collected from the 27.50-29.50(2) angular range of the powdered enamel, the (105) apatite, (225) apatite and (111) CaF2 peaks of the enamel crystallities were detected after 24h APF application.