• Journal of Radiation Protection and Research
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• v.33 no.1
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• pp.13-20
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• 2008

The flow rate measurements in a multi-phase flow pipeline were evaluated quantitatively by means of a clamp-on sealed radioisotope based on a cross correlation signal processing technique. The flow rates were calculated by a determination of the transit time between two sealed gamma sources by using a cross correlation function following FFT filtering, then corrected with vapor fraction in the pipeline which was measured by the ${\gamma}$-ray attenuation method. The pipeline model was manufactured by acrylic resin(ID. 8 cm, L=3.5 m, t=10 mm), and the multi-phase flow patterns were realized by an injection of compressed $N_2$ gas. Two sealed gamma sources of $^{137}Cs$ (E=0.662 MeV, ${\Gamma}$ $factor=0.326\;R{\cdot}h^{-1}{\cdot}m^2{\cdot}Ci^{-1}$) of 20 mCi and 17 mCi, and radiation detectors of $2"{\times}2"$ NaI(Tl) scintillation counter (Eberline, SP-3) were used for this study. Under the given conditions(the distance between two sources: 4D(D; inner diameter), N/S ratio: $0.12{\sim}0.15$, sampling time ${\Delta}t$: 4msec), the measured flow rates showed the maximum. relative error of 1.7 % when compared to the real ones through the vapor content corrections($6.1\;%{\sim}9.2\;%$). From a subsequent experiment, it was proven that the closer the distance between the two sealed sources is, the more precise the measured flow rates are. Provided additional studies related to the selection of radioisotopes their activity, and an optimization of the experimental geometry are carried out, it is anticipated that a radioisotope application for flow rate measurements can be used as an important tool for monitoring multi-phase facilities belonging to petrochemical and refinery industries and contributes economically in the light of maintenance and control of them.

• Investigative Magnetic Resonance Imaging
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• v.7 no.2
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• pp.116-123
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• 2003

Purpose : The present study was undertaken to evaluate the usefulness of cerebral diffusion (DWI) and perfusion MR imaging (PWI) in rabbit models with hyperacute cerebral ischemic infarction. Materials and Methods : Experimental cerebral infarction were induced by direct injection of mixture of Histoacryl glue, lipiodol, and tungsten powder into the internal cerebral artery of 6 New-Zealand white rabbits, and they underwent conventional T1 and T2 weighted MR imaging, DWI, and PWI within 1 hour after the occlusion of internal cerebral artery. The PWI scan for each rabbit was obtained at the level of lateral ventricle and 1cm cranial to the basal ganglia. By postprocessing using special imaging software, perfusion images including cerebral blood volume (CBV), cerebral blood flow (CBF), and mean transit time (MTT) maps were obtained. The detection of infarcted lesion were evaluated on both perfusion maps and DWI. MTT difference time were measured in the perfusion defect lesion and symmetric contralateral normal cerebral hemisphere. Results : In all rabbits, there was no abnormal signal intensity on T2WI. But on DWI, abnormal high signal intensity, suggesting cerebral infarction, were detected in all rabbits. PWI (rCBV, CBF and MTT map) also showed perfusion defect in all rabbits. In four rabbits, the calculated square of perfusion defect in MTT map is larger than that of CBF map and in two rabbits, the calculated size of perfusion defect in MTT map and CBF map is same. Any rabbits do not show larger perfusion defect on CBF map than MTT map. In comparison between CBF map and DWI, 3 rabbits show larger square of lesion on CBF map than on DWI. The others shows same square of lesion on both technique. The size of lesion shown in 6 MTT map were larger than DWI. In three cases, the size of lesion shown in CBF map is equal to DWI. But these were smaller than MTT map. The calculated square of lesion in CBF map, equal to that of DWI and smaller than MTT map was three. And in one case, the calculated square of perfusion defect in MTT map was largest, and that of DWI was smallest. Conclusion : DWI and PWI may be useful in diagnosing hyperacute cerebral ischemic infarction and in e-valuating the cerebral hemodynamics in the rabbits.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.3 no.1
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• pp.26-45
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• 1992

This study presents the behavioral and cognitive changes by administration of methylphenidate(MPH) and imipramine(IMI) for the treatment of attention-deficit hyperactivity disorder(ADHD) in $5_{1/2}{\sim}12$ years old children referred to child psychiatric clinics. Behavioral changes are assessed with parent's and teacher's ratings. Drug effects on attention. short-term memory, and impulsivity are evaluated with psychological tests in laboratory. The changes were assessed twice in a 8-week periods. The data were analyzed seperately for 15 subjects each drug using repeated measured analysis of variance(ANOVA). The findings indicates that behavioral and cognitive impairments are improved by both drugs, but impulsivity is not. And MPH is superior to IMI on the improvement of attentional problem ; especially the findings indicates important differences between simple task and complex. perceptual-search task. These data confirm the effectiveness of MPH for treatment of ADHD, also raise questions regarding assessment method of attention and impulsivity as fell as importance of impulsivity in ADHD.

• Korean Journal of Agricultural and Forest Meteorology
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• v.13 no.3
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• pp.148-156
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• 2011

The purpose of this study is to analyze the patterns of forest fire possibly related with Asian dust event and carry out a correlation analysis between forest fire occurrence and existence or not of the Asian dust event during dry seasons i.e. February to May in 2000 to 2008. To study the correlation of forest fire and Asian dust, we surveyed information of Asian dust observations, forest fire statistics, fire danger rating index, weather data such as temperature, relative humidity and wind speed of the day occurring the forest fire. As a consequence of analysis, the regional frequency of Asian dust was the highest in Gyeonggi and Chungbuk divisions. Frequencies of forest fire occurrence by the Asian dust events were the highest in the day before three days of the Asian dust event. The highest frequent regions of forest fire occurrence were district of boundary line between Gyeonggi and Western of Gangwon, Chungbuk and Gyeonbuk inland. The correlation between forest fire and fire danger rating index showed the high correlation with the day before three days and after three days of the Asian dust event. These correlation coefficients were 0.50038 and 0.53978 to 1% significance level. The result of analysis between the frequency of forest fire occurrence and wind speed had a highly negative relationship at all the Asian dust days, the day before and after three days. The correlation coefficients had been -0.58623 to -0.61245 to 1% significance level. Relative humidity showed a little of negative relationship with forest fire occurrence in -0.2568(p ${\leq}$ 0.01) for the Asian dust day and -0.35309(p ${\leq}$ 0.01) for next three days. Moreover, at the day before three days of Asian dust events, it was -0.23701 to 1% significance level. However, the mean temperature did not correlate with frequency of forest fire occurrence by Asian dust events at all.

• Resources Recycling
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• v.4 no.1
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• pp.38-45
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• 1995

The objective of this study was to investigate the effect of temperature on the formation of CaCO, polymorphs(i.e.,calcite, aragonite, vaterite) and on the crystal shape of CaCO,.The reaction systems were rnvestigated at the temperature range of 2.0%-85.3r, at the fixed cmditions ofconcentration and pressure, 2X10-' M, atomospheric pressure, respectively.The reaction systems studied include a Ca(HCO.,),-Air bubble, O Ca(OH)s-CO,, @ Ca(OH),-H,CO, ,Ca(OH1,-Na>CO,, O Ca(OH),-K,CO,, @ Ca(OH),-(NH,),CO,, D CaC1,-Na,CO,, CaC1,-K3C03, 8 CaC1,-(NH,,),CO,, 0 Ca(N0,X-Na,CO,, 03 Ca(N0,X-QCO,. 0 Ca(NO,),-(NH,XCO,. The results obtained are summarizedas follows:Calcite is formed at the temperature range of 2t-80"C and the highest calcite yield was obtained at 30%.Aragonite begins to be formed at the temperature range of 41.0%-53.0%. and the higher temperature is thehigher yield is obtained. pH of the reaction system affect the yield of aragonite, and the yield reaches the highestpercentage at the pH range of 10.0-11.0, and at the conditions of pH 12.3 or over, aragonite is scarcely formed.Vaterlle is fnrmed at the temperature range of 40.0% or less, and transites utterly to calcite within 10-60mmutes in the case of bemg residenced in mother liqmd which C1 is not contained, and within 140hours inthe case of containing CI-.s in the case of containing CI-.

• Asia Marketing Journal
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• v.13 no.4
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• pp.55-76
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• 2012

Most people prefer to choose zero-cost products they may get without paying any money. The 'zero-cost effect' can be explained with a 'zero-cost model' where consumers attach special values to zero-cost products in a different way from general economic models (Shampanier, Mazar and Ariely 2007). If 2 different products at the regular prices of ￦200 and ￦400 simultaneously offer ￦200 discounts, the prices will be changed to ￦0 and ￦200, respectively. In spite of the same price gap of the two products after the ￦200 discounts, people are much more likely to select the free alternative than the same product at the price of ￦200. Although prior studies have focused on the 'zero-cost effect' in isolation of other factors, this study investigates the moderating effects of a self-regulatory resource and a construal level on the selection of free products. Self-regulatory resources induce people to control or regulate their behavior. However, since self-regulatory resources are limited, they are to be easily depleted when exerted (Muraven, Tice, and Baumeister 1998). Without the resources, consumers tend to become less sensitive to price changes and to spend money more extravagantly (Vohs and Faber 2007). Under this condition, they are also likely to invest less effort on their information processing and to make more intuitive decisions (Pocheptsova, Amir, Dhar, and Baumeister 2009). Therefore, context effects such as price changes and zero cost effects are less likely in the circumstances of resource depletion. In addition, construal levels have profound effects on the ways of information processing (Trope and Liberman 2003, 2010). In a high construal level, people tend to attune their minds to core features and desirability aspects, whereas, in a low construal level, they are more likely to process information based on secondary features and feasibility aspects (Khan, Zhu, and Kalra 2010). A perceived value of a product is more related to desirability whereas a zero cost or a price level is more associated with feasibility. Thus, context effects or reliance on feasibility (for instance, the zero cost effect) will be diminished in a high level construal while those effects may remain in a low level construal. When people make decisions, these 2 factors can influence the magnitude of the 'zero-cost effect'. This study ran two experiments to investigate the effects of self-regulatory resources and construal levels on the selection of a free product. Kisses and Ferrero-Rocher, which were adopted in the prior study (Shampanier et al. 2007) were also used as alternatives in Experiments 1 and 2. We designed Experiment 1 in order to test whether self-regulatory resource depletion will moderate the zero-cost effect. The level of self-regulatory resources was manipulated with two different tasks, a Sudoku task in the depletion condition and a task of drawing diagrams in the non-depletion condition. Upon completion of the manipulation task, subjects were randomly assigned to one of a decision set with a zero-cost option (i.e., Kisses ￦0, and Ferrero-Rocher ￦200) or a set without a zero-cost option (i.e., Kisses ￦200, and Ferrero-Rocher ￦400). A pair of alternatives in the two decision sets have the same price gap of ￦200 between a low-priced Kisses and a high-priced Ferrero-Rocher. Subjects in the no-depletion condition selected Kisses more often (71.88%) over Ferrero-Rocher when Kisses was free than when it was priced at ￦200 (34.88%). However, the zero-cost effect disappeared when people do not have self-regulatory resources. Experiment 2 was conducted to investigate whether constual levels influence the magnitude of the 'zero-cost effect'. To manipulate construal levels, 4 different 'why (in the high construal level condition)' or 'how (in the low construal level condition)' questions about health management were asked. They were presented with 4 boxes connected with downward arrows. In a box at the top, there was one question, 'Why do I maintain good physical health?' or 'How do I maintain good physical health?' Subjects inserted a response to the question of why or how they would maintain good physical health. Similar tasks were repeated for the 2nd, 3rd, and 4th responses. After the manipulation task, subjects were randomly assigned either to a decision set with a zero-cost option, or to a set without it, as in Experiment 1. When a low construal level is primed with 'how', subjects chose free Kisses (60.66%) more often over Ferrero-Rocher than they chose ￦200 Kisses (42.19%) over ￦400 FerreroRocher. On contrast, the zero-cost effect could not be observed any longer when a high construal level is primed with 'why'.

• Analytical Science and Technology
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• v.33 no.1
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• pp.33-41
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• 2020

Wet precipitation samples were collected in Jeju City and Mt. Halla-1100 site (a site at an altitude of 1100 m on Mt. Halla) during 2011-2013, and their major ionic species were analyzed to examine the chemical composition and characteristics. A comparison of ion balance, electric conductivity, and acid fraction of precipitation revealed correlation coefficients in the range of r = 0.950~0.991, thereby implying the high quality of analytical data. Volume-weighted mean pH and electric conductivity corresponded to 4.86 and 25.5 µS/cm for Jeju City, and 4.98 and 15.1 µS/cm for Mt. Halla-1100 site, respectively. Ionic strengths of the wet precipitation in Jeju City and Mt. Halla-1100 site corresponded 0.3 ± 0.5 and 0.2 ± 0.2 mM, respectively, thereby indicating that more than 30 % of total precipitation was within a pure precipitation criteria. The precipitation with a pH range of 4.5 - 5.0 corresponded to 40.8 % in Jeju City, while the precipitation with a pH range of 5.0 - 5.5 corresponded to 56.9 % in Mt. Halla-1100 site, thereby indicating slightly more weak acidity than that in Jeju city. The volume-weighted mean concentration (µeq/L) of ionic species was in the order of Na⁺ > Cl^- > nss-SO₄^2- > NO₃^- > Mg²⁺ > NH₄⁺ > H⁺ > nss-Ca²⁺ > PO₄^3- > K⁺ > CH₃COO^- > HCOO^- > NO₂^- > F^- > HCO₃^- > CH₃SO₃^- at Jeju City area, while it corresponded to Na⁺ > Cl^- > nss-SO₄^2- > NO₃^- > NH₄⁺ > H⁺ > Mg²⁺ > nss-Ca²⁺ > PO₄^3- > CH₃COO^- > K⁺ > HCOO^- > NO₂^- > F^- > HCO₃^- > CH₃SO₃^- at Mt. Halla-1100 site. The compositions of sea salts (Na⁺, Cl^-, Mg²⁺) and secondary pollutants (NH₄⁺, nss-SO₄^2-, NO₃^-) corresponded to 66.1 % and 21.8 %, respectively, in Jeju City and, 49.9 % and 31.5 %, respectively, in Mt. Halla-1100 site. The acidity contributions in Jeju City and Mt. Halla-1100 site by inorganic acids, i.e., sulfuric acid and nitric acid, corresponded to 93.9 % and 91.4 %, respectively, and the acidity contributions by organic acids corresponded to 6.1 % and 8.6 %, respectively. The neutralization factors in Jeju City and Mt. Halla1100 site by ammonia corresponded to 29.8 % and 30.1 %, respectively, whereas the neutralization factors by calcium carbonate corresponded to 20.5 % and 25.2 %, respectively. From the clustered back trajectory analysis, the concentrations of most ionic components were higher when the airflow pathways were moved from the continent to Jeju area.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.3
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• pp.185-192
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• 1991

The vertical distribution and chemical characteristics of water masses were measured along two south-north transects in the polar front region of the central Korean East Sea. In February, a thermocline was present at depth between 50m and loom at the southern sites of a landward A-transect, and its depth was gradually deepened northward. At an outside B-transect, a thermocline was observed at significantly deep depth of 300m to 400m at two northern stations(Stn. 10 and 11), though the depth of the southward stations was nearly identical to that at the northward stations on a A-transect. In September, there were vertically more various water masses, i.e. the Tsushima Warm surface water(TWSW) or more than $20^{\circ}C$, the Tsushima Middle water(TMW) with a range of $12{\~}17^{\circ}C$, the North Korea Cold Water(NKCW) with $1{\~}7^{\circ}C$ temperature, the Japan Sea Proper Water(JSPW) of less than $1^{\circ}C$, and the mixed water. The North Korea Cold Water could be distinguishable from the other waters, especially from the mixed water of the Tsushima Middle Water and the Japan Sea Proper Water by the pattern of $T-O_2$ diagram. For instance, the North Korea Cold Water had higher oxygen by $1{\~}2ml/l$ than those in the mixed water, although both the two water masses ranged $1{\~}7^{\circ}C$ in water temperature. AOU value was the highest in the JSPW and the lowest in the TWSW. Also, AOU indicated a nearly linear and negative correlation with water temperature. However, AOU data for two masses, the NKCW and the TMW, in September departed remarkably from a regression line. Moreover, the ratio of $$\Delta P/\Delta AOU)$ in September was about $0.45{\mu}g-at/ml$ and higher than the value observed in the open sea. This high value could be elucidated by two factors; intrusion of the NKCW with high oxygen and molecular diffusion of dissolved oxygen from the surface into the lower layer. AOU would be a useful tracer for water masses in the polar front area of the Korean East Sea.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.4
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• pp.459-464
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• 2017

Biphenyl is used as an intermediate in the production of crop protection products, a solvent in pharmaceutical production, and as a component in the preservation of citrus fruits in many countries. Biphenyl is not authorized for use and also does not have standards or specifications as a food additive in Korea. National and imported food products are likely to contain biphenyl. Therefore, control and management of these products is required. In this study, a simple analytical method was developed and validated using HPLC to determine biphenyl in food. These methods are validated by assessing certain performance parameters: linearity, accuracy, precision, recovery, limit of detection (LOD), and limit of quantitation (LOQ). The calibration curve was obtained from 1.0 to $100.0{\mu}g/mL$ with satisfactory relative standard deviations (RSD) of 0.999 in the representative sample (orange). In the measurement of quality control (QC) samples, accuracy was in the range of 95.8~104.0% within normal values. The inter-day and inter-day precision values were less than 2.4% RSD in the measurement of QC samples. Recoveries of biphenyl from spiked orange samples ranged from 92.7 to 99.4% with RSD between 0.7 and 1.7% at levels of 10, 50, and $100{\mu}g/mL$. The LOD and LOQ were determined to be 0.04 and $0.13{\mu}g/mL$, respectively. These results show that the developed method is appropriate for biphenyl identification and can be used to examine the safety of citrus fruits and surface treatments containing biphenyl residues.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.2
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• pp.61-70
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• 2000

Soil erosion in the hilly and mountainous uplands in the Daekwanryong area, Kangwon-Do, were investigated through a field plot experiment. The plot size was 15m long and 2.5m wide with the average slope of 12.5 percents. Soil erodibility factor (K), surface coverage (SC), soil aggregate percentage and wind erodibility (I) were evaluated in the mountainous soils under different management practices for corn and potato cultivations. Soil erodibility factor (K) was greater in upper part than in lower part of the plots. Surface coverage (SC) values ranged from 0.01 to 0.84 depending on the amounts of crop residues. Soils having a greater crop residue in surface were less subjected to soil erosion. SC values after corn harvest were 0.4 to 0.8, while those after potato harvest were 0.4 to 0.5, indicating potato might be better than corn for erosion control. Soil aggregate percentages of the experimental plots ranged from 49.7 to 79.8%. Those were higher in potato-cultivated plots with higher surface coverage, organic fertilizer treatment and contour tillage. Soil aggregate percentage of potato-cultivated plots was significantly correlated to crop residue coverage after harvest. The dried soil aggregate percentage, showing the ranges of 26.4 to 56.4%, were higher in the plots with the increased crop residue incorporation. Wind erodibility (I) of the soil was decreased with increasing surface coverage. When soil had 26.4% of the dried aggregate percentage, wind erodibility was estimated to be $183Mgha^{-1}$ which was equivalent to soil loss of $0.5Mg\ha^{-1}day^{-1}$.