• The Journal of the Korea Contents Association
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• v.11 no.9
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• pp.443-452
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• 2011

This research aims at investigating the factors that affects the wearing of the nuclear protection equipment by radiology students. We measured the factors related to the wearing of the nuclear protection equipment based on the theory of planned behavior (TPB). We collected 192 survey records from 230 radiology students in Kwang-ju and Chun-nam providence who finished the clinical training. Based on Logistic Regression analysis, we found that the wearing of the nuclear protection equipment is statistically more probable as the level of study is lower, the scale of practicing hospital is smaller, the attitude rating is lower, and the rating of perceived behavioral control is higher. We argue that the development of educational program considering factors like the perceived behavioral control is required to enhance the degree of wearing the nuclear protection equipment in the clinical training of college students.

• Journal of Mushroom
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• v.10 no.1
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• pp.15-20
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• 2012

Ventilation effects of bottles($1,100m{\ell}$) for culturing Flammulina velutipes on its mycelial growth and mushroom production were investigated. The degree of ventilation were controlled with hole positions, upper and under, and hole sizes in the bottle lids. The ventilation effects were measured with the contents of carbon dioxide, free sugars, chitin, moisture in the bottles and with the amount of produced mushrooms from the bottles. Carbon dioxide concentrations within the culturing bottles at exponential mycelial growth period vertex were relatively high in the bottles with lids without both a sponge and an aeration hole, and in those with a smaller hole. Free sugar contents in the mycelia were the highest in those with a 47mm hole on both sides, and in those with 26~33mm holes only underside. Chitin content was the highest in those with a 26mm hole only underside. On the other hand, the lids with 42mm~47mm holes on the both sides greatly lost water and decreased the mushroom production. In conclusion, the most efficient ventilation hole sizes on the lids for bottle($1,100m{\ell}$) cultivation of Flammulina velutipes using $1,100m{\ell}$ polypropylene bottle were 19mm on both sides of the lid and 26mm on only underside. They produced more mushrooms than the control by 6~9 %.

• Korean Journal of Agricultural Science
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• v.9 no.1
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• pp.231-238
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• 1982

The study was done to determine the proper transplanting dates and seedling ages of rice when mechanical transplanting was attempted. Heading dates of the Milyang #23, developed from Tong-il rice was delayed by delayed transplanting and the percent of filling grain was also low. The proper heading dates for the variety should be the first part of August and the transplanting should be done by the end of May. The presumed last days for the transplantation was considered early part of June. 30 to 40 days old seedlings were very effective to have healthy rooting systems. However, the Milyang #15 had shown more tolerance to the late transplantation than Milyang #23 and the degree of delaying heading dates due to the delayed transplantation was rather smaller than that of the Milyang #23. Even when the Milyang #15 was transplanted on June 30, the heading dates were around the middle of August and the ripening percentage was comparatively high and yield was also high. Therefore, the proper heading dates of the Milyang #15 might be around the middle of August and transplanting dates should be the first part of June. The possible last dates of transplantation of the Milyang #15 was assumed to be the last days of June and the proper seedling ages would be 20 to 30 day after sowing.

• Safety and Health at Work
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• v.2 no.3
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• pp.282-289
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• 2011

Objectives: We sought to establish a novel method to generate nano-sized carbon black particles (nano-CBPs) with an average size smaller than 100 nm for examining the inhalation exposure risks of experimental rats. We also tested the effect of nano-CBPs on the pulmonary and circulatory systems. Methods: We used chemical vapor deposition (CVD) without the addition of any additives to generate nano-CBPs with a particle size (electrical mobility diameter) of less than 100nm to examine the effects of inhalation exposure. Nano-CBPs were applied to a nose-only inhalation chamber system for studying the inhalation toxicity in rats. The effect on the lungs and circulatory system was determined according to the degree of inflammation as quantified by bronchoalveolar lavage fluid (BALF). The functional alteration of the hemostatic and vasomotor activities was measured by plasma coagulation, platelet activity, contraction and relaxation of blood vessels. Results: Nano-CBPs were generated in the range of 83.3-87.9 nm. Rats were exposed for 4 hour/day, 5 days/week for 4 weeks to $4.2{\times}10^6$, $6.2{\times}10^5$, and $1.3{\times}10^5$ particles/$cm^3$. Exposure of nano-CBPs by inhalation resulted in minimal pulmonary inflammation and did not appear to damage the lung tissue. In addition, there was no significant effect on blood functions, such as plasma coagulation and platelet aggregation, or on vasomotor function. Conclusion: We successfully generated nano-CBPs in the range of 83.3-87.9 nm at a maximum concentration of $4.2{\times}10^6$ particles/$cm^3$ in a nose-only inhalation chamber system. This reliable method can be useful to investigate the biological and toxicological effects of inhalation exposure to nano-CBPs on experimental rats.

• Journal of the Korean Geotechnical Society
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• v.27 no.3
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• pp.63-73
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• 2011

The behavior of laterally cyclic loaded piles is affected by the magnitude and number of cycles of cyclic lateral loads as well as loading method (1-way or 2-way loading). In this study, calibration chamber tests were carried out to investigate the effects of loading method of cyclic lateral loads on the behavior of piles driven into sand. Results of the chamber tests show that the permanent lateral displacement of 1-way cyclic loaded piles is developed in the same direction as the first loading, whereas that of 2-way cyclic loaded piles is developed in the reverse direction of the first loading. 1-way cyclic lateral loads cause a decrease of the ultimate lateral load capacity of piles, and 2-way cyclic lateral loads cause an increase of the ultimate lateral load capacity of piles. The change of ultimate lateral load capacity with loading method of cyclic lateral loads increases with increasing number of cycles. It is also observed that the 1-way cyclic loads generate greater maximum bending moment than 2-way cyclic loads for piles in cyclic loading step and generates smaller maximum bending moment for piles in the ultimate state. It can be attributed to the difference in compaction degree of the soil around the piles with loading method of cyclic lateral loads. In addition, it is founded that 1-way and 2-way cyclic lateral loads cause a decrease in the maximum bending moment of piles in the ultimate state compared with that of piles subjected to only monotonic loads.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5C
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• pp.199-210
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• 2012

The effects of tunnelling in weak weathered rock on the behaviour of a pre-existing single pile and pile groups ($3{\times}3$ and $5{\times}5$ pile groups) above a tunnel have been studied by carrying out three-dimensional (3D) elasto-plastic numerical analyses. Numerical modelling of such effects considers the response of the single pile and pile groups in terms of tunnelling-induced ground and pile settlement as well as changes of the shear transfer mechanism at the pile-soil interface due to tunnelling. Due to changes in the relative shear displacement between the pile and the soil at the pile-soil interface with tunnel advancement, the shear stresses and axial pile force distributions along the pile change drastically. Based on the computed results, upward shear stresses are induced up to about Z/L=0.775 from the pile top, while downward shear stresses are mobilised below Z/L=0.775, resulting in a reduction in the axial pile force distribution with depth equivalent to a net increase in the tensile force on the pile. A maximum tensile force of about $0.36P_a$ developed on the single pile solely due to tunnelling, where $P_a$ is the service axial pile loading prior to tunnelling. The degree of interface shear strength mobilisation at the pile-soil interface was found to be a key factor governing pile-soil-tunnelling interaction. Overall it has been found that the larger the number of piles, the greater is the effect of tunnelling on the piles in terms of pile settlement, while changes of the axial pile forces for the piles in the groups are smaller than for a single pile due to the shielding effect. The reduction of apparent allowable pile capacity due to tunnelling-induced pile head settlement was significant, in particular for piles inside the groups.

• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.4
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• pp.62-71
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• 2013

This study was carried out to develope a pre-treatment technology for anaerobic digestion. Breaking down large particles into smaller particles enhances the performance of anaerobic digestion by increasing the hydrolysis of particles. A degree of hydrolysis is the most important factor determining the overall efficiency of methane production. Three types of pre-treatment devices (blade-type crusher, ozonization system, cavitation system) were set up and operated to crush solids in pig slurry in order to enhance biodegradability. The effect of pre-treatment on decreasing granular size within pig slurry by three experimental devices were compared. The highest performance of granulization of pig slurry was attained in a combination of blade-type crusher and ozonization system. In batch experiment, there was an improvement of the methane potential by combined pretreatment with crusher and cavitation. In case of pre-treated slurry, biogas and methane production were 325.9 L and 59.7% respectively, while, in untreated slurry, the production were lower; 298.8 L and 55.7%, respectively. These results indicate that higher anaerobic digestion efficiency of pig slurry can be obtained through the pre-treatment.

• The korean journal of orthodontics
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• v.26 no.5 s.58
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• pp.535-546
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• 1996

The purpose of this study was to classify mandibular dental arch forms based on Raberin's method, and to compare Raberin's arch forms with that of the Korean's, and to designate arch form of bracket level according to distance between cusp tip and buccal surface of bracket level. The sample consisted of 159 mandibular dental casts showing normal occlusion which was taken from 62 males and 97 females of the Korean, aging from 13 to 25 years. The model was taken by X-ray. The landmarks were cusp points which expressed the mandibular dental arch line of cusp tips and buccal points which were measured from cusp tips to buccal surfaces of bracket level. The landmarks on the film were digitized, and measurements and statistics were performed. The results were as follows; 1. The models were classified as type 1, type 2, type 3, type 4 and type 5 by the author, and polynomial functions of the six degree and R-square values were calculated using statistical method, and each calculated equations explained each group with the least R-square value of 0.97, and each arch forms' were plotted. 2. The distribution of type 1 was $17.6\%$, type 2 $20.8\%$, type 3 $20.8\%$, type 4 $16.3\%$ and type 5 $24.5\%$. 3. The Korean arch form was characterized by larger width, smaller height compared to the French arch form. 4. The designated arch form of bracket level, viz the distance between cusp point and buccal point was calculated. The distance between cusp point and buccal point of incisor was 1mm, canine 1.9mm, first premolar 2.5mm, second premolar 2.6mm, first molar 2.7mm and second molar 2.7mm.

• Journal of Korea Water Resources Association
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• v.35 no.5
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• pp.511-523
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• 2002

In order to develop the weir with high reaeration efficiency, the reaeration experiments at linear weir, ogee spillway type weir, and labyrinth weirs were conducted and the results were compared. The effect of roughened crest was also analyzed. It was found from the experiments that the oxygen transfer efficiency at the ogee spillway type weir was the lowest and that at the linear weir was second lowest among the weirs used in the experiments. It was also revealed that the reaeration efficiencies of the labyrinth weirs increase as the included angles become smaller. The roughened crest which causes the disintegration of overflow was found to increase the reaeration efficiency significantly. On the basis of the results of the experiments, the pilot construction of the labyrinth welt with included angle of 30 degree was made. The labyrinth weir was made up by assembling the frame and then filling the ripraps into the frame. The ripraps were exposed at the crest to split the overflow. The average value of oxygen transfer efficiency observed at the pilot weir was 0.18. It is expected that the results from the experimental study and the field data of the pilot weir would serve for the improvement of water quality by the weirs with high reaeration efficiency.

• Journal of Wetlands Research
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• v.19 no.1
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• pp.52-62
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• 2017

In this study, land surface model was used to simulate the soil moisture of South and North Korea for the past 30 years, and the difference in their variation was analyzed. In addition, satellite observed soil moisture data provided by Soil Moisture CCI was analyzed to evaluate the simulation results of VIC model. For the comparison between the simulated and observed data, the CSEOF analysis was applied to indirectly assess the performance of the VIC model rather than simply comparing soil moisture values. The results of this study are summarized as follows. First, the annual variability of soil moisture showed a similar tendency in both South and North Korea, but it was found that the soil moisture in South Korea was as high as 1%, up to 7%, higher than the soil moisture in North Korea. Secondly, the soil moisture in spring between April to June is similar in South and North Korea, whereas the soil moisture after the rainy season is up to 40% in South Korea, but remains at maximum 32% in North Korea. Third, the overall simulated soil moisture is about 4% smaller than the satellite observed soil moisture, but the degree of increase over the past 30 years is similar to that of satellite observed soil moisture. Finally, a comparison of the CSEOF from the satellite observed soil moisture and the VIC model derived soil moisture showed that the soil moisture from April to June shows a much different pattern from each other. However, in July and October, there was a slight similarity, and it was confirmed that August and September has quite similar patterns.