• Journal of the Korean earth science society
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• v.25 no.6
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• pp.428-442
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• 2004

Dustfall samples were collected by the modified American dust jar (bulk type) at 5 sampling sites in the Nakdong river area from lune 2002 to May 2003. Nineteen chemical species (Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Si, V, Zn, $Cl^-$, $NO_3^-$, $SO_4^{2-}$, and $NH_4^+$) were analyzed via the combination of ICP/AES, AAS, IC and UV. The purposes of this study were to qualitatively evaluate the chemical composition of dustfalls by examining their regional and seasonal distribution patterns. Computation of the enrichment factor showed that well-defined anthropogenic sources, particularly in Pb were found in the order Gamjeondong (industrial area), Wondong, Silla University, Samrangiin and Mulgum. The seasonal mean of soil contribution showed its highest value (16.3%) during the winter with an annual mean of 11.2%. The concentration ratio of [$SO_4^{2-}/NO_3^-$] was found to be highest (5.12) during the winter, while the lowest ratio value (3.30) was seen during the all. fall, Also regional equivalent ratios of [$SO_4^{2-}/NO_3^-$] were found in the order: Silla University (6.78), Gamjeondong (4.98), Mulgum (3.95), Wondong (3.85), and Samrangjin (2.87). Seasonal distribution of water soluble components for total dustfall were found in the order: spring (71.6%), summer (61.2%), fall (49.2%) and winter (48.6%) with a mean ratio of 57.6%. Regional contribution of sea salts of water soluble ions were found in the order: Silla university (34.5%), Gamjeondong (28.3%), Wondong (17.3%), Samrangiin (17.2%) and Mulgum (13.8%), the total mean contribution rate was 22.1%. As for the chemical composition of dustftll on the lower Nakdong river, there is a decreased influence of sea salt and artificial anthropogenic sources and increased influence of soil particle inland. Also, the total amount of deposition on the lower Nakdong river has decreased, with the river's surface serving as a confounding factor in resuspending dusts.

• Journal of radiological science and technology
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• v.40 no.2
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• pp.187-195
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• 2017

Early diagnosis for upper facial trauma is difficult by using the standard Water's view (S-Water's) in general radiograph due to overlapping of anatomical structures, the uncertainty of patient positioning, and specific patients with obese, pediatric, old, or high-risk. The purpose of this study was to analyze appropriate exposure angles through a comparison of two different protocols (S-Water's vs. reverse Water's view (R-Water's)) by using a head phantom. A head phantom and general radiograph with 75 kVp, 400 mA, 45 ms 18 mAs, and SID 100 cm. Images of R-Water's were obtained by different angles in the range of $0^{\circ}$ to $50^{\circ}$, which adjusted an angle at 1 degree interval in supine position. Survey elements were developed and three observers were evaluated with four elements including the maxillary sinus, zygomatic arch, petrous ridge, and image distortion. Statistical significant analysis were used the Krippendorff's alpha and Fleiss' kappa. The intra-class correlation (ICC) coefficient for three observers were high with maxillary, 0.957 (0.903, 0.995); zygomatic arch, 0.939 (0.866, 0.987); petrous ridge, 0.972 (0.897, 1.000); and image distortion, 0.949 (0.830, 1.000). The high-quality image (HI) and perfect agreement (PA) for acquired exposure angles were high in range of the maxillary sinus ($36^{\circ}-44^{\circ}C$), zygomatic arch ($33^{\circ}-40^{\circ}$), petrous ridge ($32^{\circ}-50^{\circ}$), and image distortion ($44^{\circ}-50^{\circ}$). Consequently, an appropriate exposure angles for the R-Water's view in the supine position for patients with facial trauma are in the from $36^{\circ}$ to $40^{\circ}$ in this phantom study. The results of this study will be helpful for the rapid diagnosis of facial fractures by simple radiography.

• Korean Journal of Ecology and Environment
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• v.39 no.3 s.117
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• pp.366-377
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• 2006

Environmental gradients and phytoplankton community were studied on a monthly basis, at 3 stations of Lake Yongdam, from April 2002 March 2004. During July to August, thermocline formed at the depth of about 10 m, but it was lowerd depth, in between 25${\sim}$30 m in October. Monthly variations of the epilimnetic (0${\sim}$5 m) TP concentrations at station 1, 2 and 3 were in the range of $5.1{\sim}36.1\;mg\;P\;{\cdot}\;m^{-3}$, $6.1{\sim}77.7\;mg\;P\;{\cdot}\;m^{-3}$ and $6.7{\sim}47.7\;mg\;P\;{\cdot}\;m^{-3}$ respectively; with higher concentrations at the upstream areas showing. Monthly average of the epilimnetic (0${\sim}$5 m) TN concentration at Station 1 was in the range of $0.88{\sim}1.73\;mg\;N\;{\cdot}\;L^{-1}$, and Station 3 was in the range of $0.94{\sim}2.77\;mg\;N\;{\cdot}\;L^{-1}$, which is higher if compared with the values of station 1. Transparency wa:s in the range of 0.8${\sim}$6.7 m, with lower values at upstream areas and higher at the downstream area. As for phytoplankton, during the winter season, diatoms had high appearance rate; during the spring season, Cyclotella comta, Aulacoseira ambigua f. spiralis, A. granulata and similar diatoms, during spring and summer Ankistrodesmus spiralis, Chodatella subsala, Crucigenia irregularis, Coelastrum cambricum, Scenedesmus ecornis v. ecornis.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.6
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• pp.631-638
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• 2010

The objective of this study was to evaluate the efficiency of zerovalent iron and basic oxygen furnace slag on arsenic stabilization in soils. For this, arsenic (V) contaminated soil and roxarsone contaminated soil were incubated after incorporation with zerovalent iron (ZVI) or basic oxygen furnace slage (BOFS) at four different levels (0%, 1%, 3%, and 5%) for 30 days and then the residual concentrations of arsenic were analysed following extraction with aqua reqia, 1N HCl and 0.01 M $CaCl_2$. The total concentration of arsenic was 2,285 mg/kg in the As(V) contaminated soil and 6.5 mg/kg in the roxarsone contaminated soil. 1 N HCl extractable arsenic concentration in the As(V) contaminated soil was initially 1,351 mg/kg and this was significantly declined by 713~1,034 mg/kg following incubation with ZVI while BOFS treatment showed no effect on the stabilization of inorganic arsenate except 5% treatment which showed around 100 mg/kg reduction in 1N HCl extractable arsenic. Similarly, in the roxarsone contaminated soil 1N HCl extractable concentration of arsenic was reduced from 3.13 mg/kg to 0.69 mg/kg with ZVI treatment increased from 1% to 5% while BOFS treatment did not lead to any statistically significant reduction. Available (0.01M $CaCl_2$ extractable) arsenic was initially 0.85 mg/kg in the As(V) contaminated soil and this declined by 0.79 mg/kg following incorporation with 5% ZVI, which accounted for more than 90% of the available As in the control. When As(V)-contaminated soil was treated with BOFS, the available arsenic was increased due to competing effect of the phosphate originated from BOFS with arsenate for the adsorption sites. For the roxarsone contaminated soil, the greater the treatment of ZVI or BOFS, the lower the available arsenic concentration although it was still higher than that of the control.

• Journal of the Korean Society of Radiology
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• v.5 no.2
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• pp.73-80
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• 2011

Questionnaires were distributed to Radiology departments at hospitals with 300 sickbeds throughout the Pohang region of North Gyeongsang Province concerning awareness and performance levels of infection control. The investigation included measurements of the pollution levels of imaging equipment and assistive apparatuses in order to prepare a plan for the activation of prevention and management of hospital infections. The survey was designed to question respondents in regards to personal data, infection management prevention education, and infection management guidelines. The ATP Public Heath Monitering System was used to measure seven items for pollution levels of imaging equipment and assistive apparatuses in the Radiology Department. Data was analysed using SPSS version 12.0 for paired t-test and Pearson coefficient with a statistically significant level of 0.05. The results of the survey showed a total awareness level of infection management prevention education averaged at $3.73{\pm}0.64$ and performance levels resulted at $3.39{\pm}0.83$ which were statistically significant (p = 0.01). Also the measurements of pollution levels for equipment with high patient contact showed a Pearson Coefficient of over 0.5 implying a focus on pathogenic bacterium. There was no statistical significance with the frequency of imaging (p < 0.05). Therefore for general hospitals with high patient contact, there is a need to supply analyzing equipment for real time monitoring and the implementation of disinfection management that uses a Ministry of Health and Welfare approved antiseptic solution twice every minute.

• Journal of Life Science
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• v.20 no.1
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• pp.90-96
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• 2010

Menopause increases the onset of hypertension and heart disease. Whereas it increases the blood LDL-cholesterol, triglyceride and total-cholesterol levels, the HDL-cholesterol concentration is reduced. Accordingly, we examined the effect of internal organs of Todarodes pacificus (IOT) on improvement in blood flow ability and changes in serum lipid content by using ovariectomized rats. For this study, the following four groups of 9-week-old Sprague-Dawley strain female rats were evaluated over 6 weeks: normal rats (SHAM), ovariectomized rats (CON) and ovariectomized rats that were treated with IOT extracts. Ovary removal promoted platelet aggregability. However, IOT administration in the CON group after ovary excision resulted in a hinderance of coherence. The blood vessel passing time of ovariectomized rats was slower than the SHAM group. But the blood flow ability, which was slowed down for ovary removal, was improved by IOT administration. Serum triglyceride levels were significantly reduced by IOT administration. Moreover, blood HDL-cholesterol levels were reduced by ovary removal. However, IOT administration after ovary excision significantly increase HDL-cholesterol levels. The biological activity of IOT could be confirmed from these results. Moreover, IOT can be used in the development of functional foods which are meant to improve blood circulation and anti-platelet aggregation function. According to these results, we could know that IOT improved blood flow and anti-platelet aggregation. Therefore, it is expected that IOT can be used for the development of functional foods.

• Clean Technology
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• v.24 no.3
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• pp.198-205
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• 2018

This study investigated the influence of catalyst preparation on the activity of $Co-CeO_2$ catalyst for $N_2O$ decomposition. $Co-CeO_2$ catalysts were synthesized by co-precipitation and incipient wetness impregnation. In order to estimate the performance of the as prepared catalysts, direct catalytic $N_2O$ decomposition test was carried out under $250{\sim}375^{\circ}C$. As a result, the catalyst prepared by co-precipitation (CoCe-CP) showed an enhanced performance on $N_2O$ decomposition reaction even in the presence of $O_2$ and/or $H_2O$, whereas the impregnation catalyst (CoCe-IM) did not. In order to investigate the difference in catalytic activity, characterization such as XRD, BET, TEM, $H_2-TPR$, $O_2-TPD$, and XPS was conducted. It is confirmed that the particle size and specific surface area were changed depending on the catalyst preparation method and the synthesis process influenced the physical properties of the catalysts. In addition, the improvement in the activity of the catalyst prepared by co-precipitation is due to the enhanced reduction from $Co^{3+}$ to $Co^{2+}$ and the improved oxygen desorption rate. However, it has been confirmed that the surface electron state and binding energy, which are related to $N_2O$ decomposition, do not change depending on the preparation method.

• Journal of the Korean Society of Radiology
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• v.15 no.2
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• pp.265-271
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• 2021

The pattern of the tree's internal swelling depends on many causes. Since it is difficult to detect these various causes of swelling with a general method, if the state of swelling for a long time cannot be confirmed, serious damage to the trees may occur due to enlargement of the swelling area. In the method of acquiring a tree tomography image, an impulse passing through the tree is generated by tapping the sensor with a rubber mallet, and the moving speed is recorded. In this paper, to measure cracks, cavities, and swelling due to physical damage, we developed a 3D viewer that can know the internal state of a tree using a tree cross-section image acquired from Arbotom to determine the degree of swelling inside the tree. Based on this, we tried to present data that can be referred to when surgical operation of trees is required. In order to acquire a tomographic image of a tree, 6 sensors were attached to the three Yangpala and Maple trees, and a 1 m-long tree was measured using the Arbotom program, and a 3D image was implemented through the 3D Viewer created using MATLAB. In addition to simply acquiring images, the cross-sectional length and volume of the tree were measured. In the actually produced 3D Viewer, the length of the part where the swelling of the maple tree occurred was 33.12 cm, and the swelling of the yangpala tree was measured as 21.41 cm. The volume of the maple tree was measured to be 78.832 ㎤. As a result of comparing the cross-sectional image of the Arbotom and the 3D image, the same result as the real aspect of the tree was obtained, so it can be judged that the reliability of the manufactured software is also secured, and data to be applied to the surgical tree operation through the created Viewer is provided. It is believed that the damage will be minimized.

• Korean Chemical Engineering Research
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• v.56 no.6
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• pp.871-877
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• 2018

Storing the surplus energy from renewable energy resource is one of the challenges related to intermittent and fluctuating nature of renewable energy electricity production. $CO_2$ methanation is well known reaction that as a renewable energy storage system. $CO_2$ methanation requires a catalyst to be active at relatively low temperatures ($250-500^{\circ}C$) and selectivity towards methane. In this study, the catalytic performance test was conducted using a pressurized bubbling fluidized bed reactor (Diameter: 0.025 m and Height: 0.35 m) with $Ni/{\gamma}-Al_2O_3$ (Ni70%, and ${\gamma}-Al_2O_3$30%) catalyst. The range of the reaction conditions were $H_2/CO_2$ mole ratio range of 4.0-6.0, temperature of $300-420^{\circ}C$, pressure of 1-9 bar, and gas velocity ($U_0/U_{mf}$) of 1-5. As the $H_2/CO_2$ mole ratio, temperature and pressure increased, $CO_2$ conversion increases at the experimental temperature range. However, $CO_2$ conversion decreases with increasing gas velocity due to poor mixing characteristics in the fluidized bed. The maximum $CO_2$ conversion of 99.6% was obtained with the operating condition as follows; $H_2/CO_2$ ratio of 5, temperature of $400^{\circ}C$, pressure of 9 bar, and $U_0/U_{mf}$ of 1.4-3.

• Research in Plant Disease
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• v.29 no.3
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• pp.276-285
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• 2023

This work investigated the viral infection in jujube plants in Korea. A total of 61 samples with the symptoms of putative viral infection were collected from experimental fields and orchards. Thereafter, the samples were subjected to metatranscriptome analysis, Reverse transcription polymerase chain reaction analysis, and nucleotide sequence analysis. These analyses identified the presence of two DNA viruses, jujube-associated badnavirus (JuBV), jujube mosaic-associated virus (JuMaV), and one RNA virus, jujube yellow mottle-associated virus (JYMaV). All samples collected were confirmed to be infected by at least one of the three viruses, with most showed multiple infections. The detection rates of JuBV, JYMaV, and JuMaV were 100%, 90.2%, and 8.2%, respectively. Only three combinations of viral infections were found: 9.8% of samples showed single infection of JuBV, 82.0% showed double infection of JuBV+JYMaV, and 8.2% showed triple infection of JuBV+JYMaV+JuMaV. Sequence analysis of the three viruses showed very high homology with respective virus isolates reported in China. This study is predicted to provide fundamental data to produce virus-free jujube seedlings and represents the first report of JuBV and JuMaV infection in Korea.