• Journal of the Korean Society of Groundwater Environment
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• v.5 no.1
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• pp.1-9
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• 1998

Schlumberger soundings and dipole-dipole electrical surveys were carried out in and around the Nanjido waste landfill in August and December, 1995. Survey points were set to be identical as those in August, 1994 and February, 1995 as possible. To elucidate the annual variation of resistivity structure in and around the landfill, 50 electrical soundings and 2 lines of dipole-dipole surveys were conducted. Interpretations of these data show that mean resistivity values become lower and thicknesses of contaminated layers by leachate thicker than those of the previous year in and around the landfill. Especially, mean thicknesses of saturated layers with leachate increased by about 3∼6 m and resistivities of bedrock decreased. Considering actual hydraulic conductivity, such increments of mean thicknesses are somewhat large. But resistivity variations in and around the Nanjido landfill clearly indicates contamination of layers by leachate is in progress even though some errors in measurements and interpretations are considered. On the other hand, sounding data in the back area of the landfill are almost identical to those of the previous year. From these results, it appears that contamination of weathered zone and bed rock is in progress mainly inside and in the front area of the landfill.

• Environmental and Resource Economics Review
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• v.15 no.2
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• pp.147-175
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• 2006

This paper attempts to incorporate three important factors-perceptions, behavior and valuation-in analysing consumers' responses to health risks from environmental pollutants. Using a survey sample of 500 consumers in the Chonbuk province area, this paper empirically investigated determinants of risk perceptions from using tap water as drinking water. Most consumers were considerably concerned about health risks from drinking tap water. Moreover, those subjective concerns were not random, but were systematically related to individuals' demographic variables such as age, gender, and family size. Those subjective beliefs also influenced respondents' purchase intentions on safer water bottles, in response to a contingent behavior question of presenting two types of water bottles. The technical risk information provided in the survey had significant effects on purchase intentions only when it was interacted with respondents' actual averting practice. In addition, the sample selection effects were present by eliminating respondents who decided not to purchase either of two types of water bottles. The potential selection bias had impacts on the coefficients of the price difference variable, and subsequently the estimates of the price increments for health risk reductions.

• The Journal of Engineering Geology
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• v.25 no.1
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• pp.35-43
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• 2015

A method is proposed to estimate groundwater usage for water curtain cultivation (WCC) using a rating curve, and it is applied to field measurements of groundwater discharge used for WCC in Wangjeon-ri, Nonsan. During the winter season, the hydraulic components of irrigation ditches in the study area consist mainly of direct run-off and groundwater discharged from nearby pumping wells. Changes in stage of the ditches were monitored, and a baseflow separation method was applied to remove increments in stage due to direct run-off. The resulting records of stage were translated to groundwater discharge by applying the-stage-discharge relation. The estimated average groundwater discharge for the WCC in Wangjeon-ri was 10,900 m³/d or 420 m³/d/ha when the estimation is normalized by the total area for WCC facilities of this region. Applying this estimation (420 m³/d/ha) to the entire area of the WCC in Korea (10,746 ha),and considering the number of pumping days for the WCC (120 days/year), the total ground water usage for the WCC nation-wide is estimated to be 0.54 billion m³. This is equivalent to 32% of the total groundwater discharge for agricultural use in Korea (1.7 billon m³).

• Journal of the Korean Society of Environmental Restoration Technology
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• v.19 no.6
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• pp.77-86
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• 2016

Due to aging of the rural and mountain populations the labor force is reduced. However work intensity continues to increase, thus, there is a need to improve the current effectiveness of forest operations. This study compared and analyzed the Operation productivity and efficiency of planting containerized seedlings using a battery-powered planting auger and a mattock. Growth was also investigated by looking into the initial growth increments in the planted seedlings. Tasks were investigated by analyzing the process and operation time needed to plant 1 containerized seedling using a planting auger and a mattock. The time spent on the various elements of the planting process was measured with a stopwatch but observations were done continuously. Result of the study shows that with the use of a lightweight planting auger the average time spent to plant a containerized seedling is 18.61 seconds while with the use of a mattock it took an average of 26.96 seconds which clearly demonstrates that the planting auger is more efficient in terms of working hours. Working intensity was also analyzed with the use of a portable heart rate monitor (Polar V800). The average increase in heart rate and work intensity index were analyzed for one planting cycle. It was observed that when using the lightweight planting auger, there was a 46.51% increase in the average heart rate while a 74.67% increase in heart rate when the mattock was used which shows that there is a significant increase in heart rate when mattock is used. In addition, work intensity index was observed to be 29.95% and 47.83% when the planting auger and mattock were used respectively. With the continuous use, work intensity index is significantly higher with the use of the mattock as compared to that of the lightweight planting auger. There were no significant differences on the growth increment of seedlings planted using the different tools until a year after planting, however differences in growth increment were observed after a year. A difference of 15.1 cm in height and 3.41 mm in diameter was observed which shows that the use of lightweight planting auger is excellent for planting containerized seedlings.

• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.45-51
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• 2005

$K^+-{\beta}^{{\prime}{\prime}}-Al_2O_3$ in the $K_2O-Li_2O-Al_2O_3$ ternary system was synthesized using aluminum nitrate solution as a starting material. For the synthesis of pure $K^+-{\beta}^{{\prime}{\prime}}-Al_2O_3$, raw materials with chemical composition of $0.84K_2O{\cdot}0.082Li_2O{\cdot}5.2Al_2O_3$ were mixed in solution state. The effects of dispersant and solution-pH were investigated in minimizing the particle size and on the synthesis of pure $K^+-{\beta}^{{\prime}{\prime}}-Al_2O_3$. Ethanol was used for a dispersant, and $NH_4OH$ solution and nitric acid were added for pH adjustment. The solution pH was increased from 1.0 to 7.5 by 0.5 increments. Each sample was calcined at $1200^{\circ}C$ for 2 h and characterized with X-ray diffraction and particle size analyzer. The pH of solution significantly effected both particle size and phase formation, while the addition of ethanol only effected particle size. The synthesis of pure $K^+-{\beta}^{{\prime}{\prime}}-Al_2O_3$ was favored by addition of nitric acid (for pH control).

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.4
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• pp.415-425
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• 1999

$[K^+]_o$ can be increased under a variety of conditions including subarachnoid hemorrhage. The increase of $[K^+]_o$ in the range of $5{\sim}15$ mM may affect tensions of blood vessels and cause relaxation of agonist-induced precontracted vascular smooth muscle $(K^+-induced$ relaxation). In this study, effect of the increase in extracellular $K^+$ concentration on the agonist-induced contractions of various arteries including resistant arteries of rabbit was examined, using home-made Mulvany-type myograph. Extracellular $K^+$ was increased in three different ways; from initial 1 to 3 mM, from initial 3 to 6 mM, or from initial 6 to 12 mM. In superior mesenteric arteries, the relaxation induced by extracellular $K^+$ elevation from initial 6 to 12 mM was the most prominent among the relaxations induced by the elevations in three different ways. In cerebral arteries, the most prominent relaxation was produced by the elevation of extracellular $K^+$ from initial 1 to 3 mM and a slight relaxation was provoked by the elevation from initial 6 to 12 mM. In superior mesenteric arteries, $K^+-induced$ relaxation by the elevation from initial 6 to 12 mM was blocked by $Ba^{2+}\;(30\;{\mu}M)$ and the relaxation by the elevation from 1 to 3 mM or from 3 to 6 mM was not blocked by $Ba^{2+}.$ In cerebral arteries, however, $K^+-induced$ relaxation by the elevation from initial 3 to 6 mM was blocked by $Ba^{2+},$ whereas the relaxation by the elevation from 1 to 3 mM was not blocked by $Ba^{2+}.$ Ouabain inhibited all of the relaxations induced by the extracellular $K^+$ elevations in three different ways. In cerebral arteries, when extracellular $K^+$ was increased to 14 mM with 2 or 3 mM increments, almost complete relaxation was induced at 1 or 3 mM of initial $K^+$ concentration and slight relaxation occurred at 6 mM. TEA did not inhibit $Ba^{2+}-sensitive$ relaxation at all and NMMA or endothelial removal did not inhibit $K^+-induced$ relaxation. Most conduit arteries such as aorta, carotid artery, and renal artery were not relaxed by the elevation of extracellular $K^+.$ Among conduit arteries, trunk of superior mesenteric artery and basilar artery were relaxed by the elevations of $[K^+]_o.$ These data suggest that $K^+-induced$ relaxation has two independent components, $Ba^{2+}-sensitive$ and $Ba^{2+}-insensitive$ one and there are different mechanisms for $K^+-induced$ relaxation in various arteries.

• Journal of Microbiology and Biotechnology
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• v.13 no.5
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• pp.759-766
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• 2003

Recombinant Chinese hamster ovary (rCHO) cell lines expressing a high level of human thrombopoietin (hTPO) or its analog, TPO33r, were obtained by transfecting expression vectors into dihydrofolate reductase-deficient (dhfr) CHO cells and subsequent gene amplification in media containing stepwise increments in methotrexate (MTX) level such as 20, 80, and 320 nM. The parental clones with a hTPO expression level $>0.40\;{\mu}g/ml$ (27 out of 1,200 clones) and the parental clones with a TPO33r expression level $>0.20\;{\mu}g/ml$ (36 out of 400 clones) were subjected to 20 nM MTX. The clones that displayed an increased expression level at 20 nM MTX were subjected to stepwise increasing levels of MTX such as 80 and 320 nM. When subjected to 320 nM MTX, most clones did not display an increased expression level, since the detrimental effect of gene amplification on growth reduction outweighed its beneficial effect of specific TPO productivity ($q_{TPO}$) enhancement at 320 nM MTX. Accordingly, the highest producer subclones ($1-434-80^{*}$ for hTPO and $2-3-80^{*}$ for TPO33r), whose $q_{TPO}$ was 2- to 3-fold higher than that of their parental clones selected at 80 nM MTX, were isolated by limiting dilution method and were established as rCHO cel1 lines. The $q_{TPO}$ of $1-434-80^{*}\;and\;2-3-80^{*}\;was\;5.89{\pm}074\;and\;1.02{\pm}0.23\;{\mu}g/10^6$ cells/day, respectively. Southern and Northern blot analyses showed that the enhanced $q_{TPO}$ of established rCHO cell lines resulted mainly from the increased TPO gene copy number and subsequent increased TPO mRNA level. The hTPO and TPO33r produced from the established rCHO cell lines were biologically active in vivo, as demonstrated by their ability to elevate platelet counts in treated mice.

• Journal of Navigation and Port Research
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• v.32 no.8
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• pp.645-652
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• 2008

The interest on the marine leisure sports is rapidly increasing with the advent of the five-day week and with increments of GNP. The self-governing bodies are trying to drag large investments into the marine leisures industry through international exhibitions and yacht rallies. Unfortunately, the demands in the domestic area don't increase differently from those demand patterns in the advanced countries. In this study, several suggestions for vitalizations on the marine leisure industry are made after surveying the recognition degree of the domestic people on the marine leisures and the current states of their spending on the marine leisures. As results, it has been shown that the policies based upon negative factors coming from negative understandings on the leisure activities should be largely revised. Further, it seems that the policies for the preparations of the laws and the regulations for the marine leisures as well as for the R&D policies should be taken systematically so that the infra structures are constructed while improving the negative understandings on the leisures. The fundamental databases investigated in this study will help the policy makers and the investors reduce the risks of the policy and the investments in the field of marine leisure sports.

• The korean journal of orthodontics
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• v.28 no.4 s.69
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• pp.659-668
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• 1998

The purpose of this study was to evaluate the possibility of the decrease of bond strength due to increased thickness of resin base in indirect bracket bonding technique. Metal brackets were bonded to the resin blocks involving bovine lower incisors and the thickness of resin bases was increased by increments of 0.5 mm from 0.0 mm to 2.0 mm. They were divided into two groups, one group is that the thickness of resin base was increased but the loading point from the tooth surface was maintained constantly, the other group is that the loading point from the tooth surface and the resin base thickness were increased concomitantly. The shear bond strength was tested on universal testing machine and the failure patterns were assessed with the adhesive remnant index(ARI). The results were as follows: 1. When the distance from the tooth surface to the loading point was maintained constantly, shear bond strength was increased significantly according to the decrease of distance from the bracket base to the loading point and the increase of resin base thickness. 2. When the distance from the tooth surface to the loading point and the resin base thickness were increased concomitantly, shear bond strength was decreased according to the increase of resin base thickness but significant differences were ignorable. 3. There were no significant differences in ARI scores according to the change in the thickness of resin base. The results of the present study indicated that shear bond strength was not much affected by the thickness of resin base, whereas was decreased according to the increase of distance from bracket base to the loading point.

• The Korean Journal of Malacology
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• v.29 no.2
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• pp.121-127
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• 2013

In this study, growth-line analysis was carried out on the hard clam (Meretrix petechialis) collected from the Neolithic shell middens in Daejuk-ri, Seosan, Korea, to reconstruct palaeoenvironment. Growth increments of 206 specimens of the clam were examined. The ages of the specimens were determined from the rings on the shells. The relationship between shell length and ring radius in each ring group was expressed as a regression line, indicating a correspondence in each ring formation. Growth pattern of the midden specimens was compared to that of modern ones collected from Gimje, Jeonbuk. Growth curves for shell length fitted to the von Berta anffy's growth curve were expressed respectively as follows: $SL_t=102.9025[1-e^{-0.18657(t+1.0906)}]$ in the shell midden specimens, $SL_t=104.2583[1-e^{-0.2277(t+0.7499)}]$ in the modern ones. The relationship between shell length (SL; mm) and shell height (SH; mm) was expressed by the following equations: SH = 0.7791 SL + 3.6636 ($R^2$ = 0.946) in the midden specimens, SH = 0.8103 SL + 0.5145 ($R^2$ = 0.991) in the modern ones. The results of the tests regarding the differences between regression coefficients and elevations of growth curves of these two populations demonstrate that the slopes were not significantly different (p < 0.05), but the elevations were (p > 0.05). However, overall growth curves of the midden and modern populations were not significantly different, indicating that shell growth environments of the two areas are similar. Therefore, it is likely that sea temperature near the midden area could be similar to that of present Gimje area, and thus temperature during the period of the midden formation could be higher than presently known.