• The Korean Journal of Ecology
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• v.1 no.2
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• pp.44-48
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• 1977

The spawning behavior and developmental pattern of the Korean eleotrid fish (Odontobutis obscurus) was investigated in one of the tributary of Han River. The spawining of this species begins on April and continues up to August, whereas, the spawning. of same species were between the end of June and the middle of July in Kyushu, Japan. August The spawning places were the margin of river, its the bottom composed of sand and pebble (Table 5). The velocity of water in the spawning places was 0-40cm/sec, and the depth of waters was 10-40cm. The egg was spawned on underside of stone in the spawning places with one or two folds and ellipsoid in shape, 3.4mm in long diameter and 2.0mm in short diameter. The yolk is 1.2mm in diameter and yellow in color. For hatching of the egg, it takes one month in, $16^{circ}C~19^{\circ}C$ water, in Japan, whereas it takes only 14 days in $20^{circ}C~30^{\circ}C$ wate rin the study area. The growth rate of larva and juvenile fish were as follows: new hatched larva is 45mm in length; after 5 days it became 5.0 to 5.5mm in length and 1.2 to 1.5mm in height after 20 days. it became 11.0mm in length and 2.3mm in length. The mean size of the mature female is 110mm in total length and larger 10mm than that of the same fish found in Japan.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.12 no.3
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• pp.1-8
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• 2016

In this study, we evaluated the flow characteristics of various types of waveguide-below-cutoff (WBC) arrays and their shielding effectiveness (SE) of electromagnetic pulses (EMP) based on computational fluid dynamics (CFD). Three types of waveguides were selected for analysis: (1) grid type, (2) honeycomb type, and (3) multi-layer types (2-ply, 4-ply, 6-ply, and 8-ply). To analyze the air flow characteristics, the flow velocities in the longitudinal center of the WBC and the differential pressures between the WBC array inlet and outlet were evaluated. Consequently, we derive the following conclusions: (1) despite an increase in the inlet velocity, the pressure drop of the 6-ply multi-layer type did not significantly increase as compared to that of other types of waveguides (waveguide thickness of 0.1 mm, SE of 100 dB); (2) the grid and honeycomb type had the fastest flow rate of 17.5 m/s, which is approximately 2.5 m/s faster than that at the inlet (waveguide thickness of 1 mm, module size of 30 mm); and (3) the average pressure drop of the grid type waveguide is the lowest in the overall model, whereas that of the 8-ply is the highest (waveguide thickness of 1 mm, module size of 30 mm, and SE of 80, 100 dB).

• Journal of Korean Society of Forest Science
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• v.95 no.4
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• pp.381-387
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• 2006

This study tried to develop a model which can predict a long-term of forest recreation quantity corresponded with econometrics. Simultaneously this study was conducted with the aim of development of practical matrix which is able to apply forest recreation management with policy-control variables about forest supplement with some problem of former study using only a cross-section analysis. As the results of analyses, forest recreation quantity is affected (-) relation by distance, (+) relation by population of the origin area, the size of forest, and a destination's annual social expenditure. In addition, the distance variable is elastic, however, the other variables are inelastic. This results might correspond to a general gravity model theory about forest recreation quantity.

• Journal of Korean Society of Forest Science
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• v.95 no.4
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• pp.468-475
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• 2006

This study examined the economic effects of low tree-form culture, Cost-Benefit analysis was done based on additional costs and benefits from investment in low tree-form culture. In addition, this study analysed the sensitivity of profitability due to the changes in chestnut prices and wages. Investment in low tree-form culture was analysed to be profitable in Chungju, Gongju and Buyeo areas but in Jinju area. Sensitivity analysis of changes in prices and wages also showed that investment in low tree-form culture was economically feasible in Chungju, Gongju and Buyeo areas except for Jinju area.

• Journal of Korean Society of Forest Science
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• v.97 no.4
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• pp.458-466
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• 2008

This study was carried out to forecast long-term supply and demand of chestnut and to analyze the impacts of change in the environment of domestic and international chestnut markets. For these ends, the study developed a partial equilibrium market model, in which in-shelled chestnut market was vertically linked to shelled chestnut market. To examine the predictive ability of the model for the endogenous variables ex-post simulation was run for the period 1990 through 2003. In general, all endogenous variables reproduced the historical trends during the period except for disuse areas and newly established areas. The results of forecasting supply and demand show that domestic in-shelled chestnut production is estimated to decrease slightly from 76,447 ton in 2005 to 76,286 ton in 2020 and that exports of shelled chestnut continue to be decreased.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.5
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• pp.375-379
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• 2011

Introduction: This study examined the effect of autogenous tooth bone used as a graft material for bone regeneration in an artificial bony defect of minipigs. Materials and Methods: Four healthy minipigs, weighing approximately 35-40 kg, were used. Four standardized artificial two-walled bony defects, 5 mm in length and depth, were made on the bilateral partial edentulous alveolar ridge on the mandible of minipigs, and autogenous tooth bone was augmented in the right side as the experimental group. On the other hand, only alloplastic bone graft material HA was grafted with the same size and manner in the left side as the control group. All minipigs were sacrificed at 4 weeks after a bone graft and evaluated histologically by Haematoxylin-eosin staining. The specimens were also evaluated semi-quantitatively via a histomorphometric study. The percentage of new bone over the total area was evaluated using digital software for an area calculation. Results: All specimens were available but one in the left side (control group) and two in the right side (experimental group) were missing during specimen preparation. The amount of bone formation and remodeling were higher in all experimental groups than the control. The mean percentage area for new bone in the experimental and control groups was $43.74{\pm}11.96%$ and $30.79{\pm}2.93%$, respectively. Conclusion: Autogenous tooth bone is a good alternative to autogenous bone with the possible clinical feasibility of an autogenous tooth bone graft in the reconstruction of bony defects.

• Journal of Korean society of Dental Hygiene
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• v.20 no.5
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• pp.623-633
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• 2020

Objectives: Since scaling has been covered by insurance, the number of patients undergoing scaling has increased. Simultaneously, legal disputes around scaling have increased. Therefore, this study was aimed at comparing the differences between the perceptions of dental hygienists and patients regarding the scaling procedure and providing dental hygienists with basic data to find ways to reduce disputes arising from these differences. Methods: A survey was conducted on 119 dental hygienists working in Busan and the South Gyeongsang Province and 110 patients who visited hospitals for scaling. Frequency analyses were performed for dental hygienists' scaling behavior and patient discomfort during scaling. The independent t-test and chi-square test were performed to compare the perceptions of dental hygienists and patients regarding the scaling procedure. Results: Polishing after scaling was performed according to 70.1% of dental hygienists but only 29.9% of patients. Oral health education was provided according to 20.4% of dental hygienists, while 79.6% of patients said that they received oral health education at the Dentiform. The scaling time was reported to be shorter by patients than by dental hygienists. Both dental hygienists and patients said that legal action was required if problems occurred during scaling, and the refund standard was that patients needed it more than dental hygienists. Conclusions: There are differences between the perceptions of dental hygienists and patients regarding scaling. Dental hygienists should identify these differences and try to prevent conflicts or disputes with patients around scaling.

• 한국해양학회지
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• v.4 no.1
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• pp.9-16
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• 1969

The sand drift movement at Young Il Bay area was tentatively investigated using Co-60 glass sand. Grain size and specific gravity of the glass sand which has originally contained natural cobalt, Co-59, was made similar to those of the real coastal sand, and was irradiated in a beam port of the reactor Triga Mark II to make the glass sand radioactive by the reaction of 59Co(n, r)60Co. The radioactive cobalt glass sand was deposited on the preselected point of sea bed, and, after a couple of weeks, the drift of sand was traced by means of specially designed water-proof G-M detector. Net counts at each point were plotted to figure out equicount lines and consequently such aspects as the direction of sand drift movement, the scope of distribution and the relative drift velocity etc. were indicated.

• Korean Journal of Veterinary Research
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• v.52 no.3
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• pp.163-167
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• 2012

Mosapride stimulated dietary motility was introduced because of the arrhythmogenic effect of cisapride. Cisapride, 5-HT receptor agonist, induces prolongation of QT interval. Additionally, this condition can raise the possibility of acute, "malignant" arrhythmias such as torsade de pointes. It is hard to find any reports about effects of mosapride on cardiac parameters in dogs. By confirming electrocardiogram (ECG) parameters, the surface extremity leads ECG that was obtained from the four-limb electrodes and which was recorded by an ECG recorder after administration of mosapride 3 mg/kg PO b.i.d, and mosapride 3 mg/kg with itraconazole 5 mg/kg PO b.i.d, respectively. QT interval was shortened on the days of 3, 5, and post-day 1 in both mosapride 3 mg/kg administrated group and mosapride with itraconazole group. Heart rate increased significantly. QTc was slightly prolonged in mosapride administration group and mosapride with itraconazole group. However, all dogs of QTc were in normal variation (150~250 msec). Besides, the dogs showed no side effects reported in human medicine during the administration with these drugs. Although mosapride can increase the heart rate, this study suggest that mosapride may be useful for the dogs with disorders of gastrointestinal motility because of no fatal arrhythmogenic effect inspite of administration with itraconazole in dogs.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.12 s.255
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• pp.1203-1210
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• 2006

The filmwise condensation heat transfer coefficients of R-134a on the horizontal copper and stainless steel tubes were measured and analyzed. The outside diameter of the tubes was 15.88 mm, and the tube thickness ranged from 0.89 to 1.65 mm. The polished stainless steel tube had an RMS surface roughness($R_q$) of 0.37 $\mu$m, and commercial stainless steel tubes had an surface roughness($R_q$) of 1.855 $\mu$m. The tests were conducted at the saturation temperatures of 20 and $30^{\circ}C$, and the liquid wall subcoolings from 0.4 to $2.1^{\circ}C$. The measured condensation heat transfer coefficients were significantly lower than the predicted data by the Nusselt analysis. This trend in the stainless steel tube was explained by the effects of thermal resistance of tube material and surface roughness. Based on the experimental data with respect to wall thickness and surface roughness, it was suggested that the existing correlation on external condensation should be modified by considering material and surface roughness factors. The revised correlation was developed by introducing the effects of wall thickness and surface roughness into the Nusselt equation. The average deviation of the revised correlation was 13.0 %.