• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.1
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• pp.212-221
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• 2001

This paper deals with the design techniques for underwater acoustic basin. An underwater acoustic basin is needed for test and calibration of acoustic sensors, acoustic digital communication system, acoustic measurement system, and underwater image data telemetry system. KRISO(Korea Research Institute of Ships and Ocean Engineering) have planned the construction of an underwater acoustic tank from 1999 to 2001 through internal project. We studied about absorbtion characteristics of a porous re-cycled rubber which is selected as a absorption materials and designed absorption plate with wedge shape. The simulation of reflection analysis along the wedge angle for wedged type plate was presented.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.371-377
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• 2000

This paper deals with the design techniques for underwater acoustic basin. An underwater acoustic basin is needed for test and calibration of acoustic sensors, acoustic digital communication system, acoustic measurement system, and underwater image data telemetry system. KRISO(Korea Research Institute of Ships and Ocean Engineering) have planned the construction of an underwater acoustic tank from 1999 to 2001 through internal project. We studied about absorbtion characteristics of a porous re-cycled rubber which is selected as a absorption materials and designed absorption plate with wedge shape. The simulation of reflection analysis along the wedge angle for wedged type plate was presented.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.1
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• pp.34-42
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• 2011

It's been reported that the global warming effect has invoked the ever increasing typhoon intensity and long-term sea level rise which jointly cause severe wave overtopping over breakwaters or shore dykes. A simple measure to cope with this undesirable change may be just to increase the crest height of the dykes and breakwaters. This is surely effective to prevent wave overtopping, but it also decreases the seaward visibility of coastal waterfront. In this paper, a dynamic deformable rubber membrane parapet which not only reduces wave overtopping in storm period but also secures seascapes in normal days is presented. Several optimal configurations of the parapet are proposed. Through numerical analyses using a nonlinear finite element model and hydraulic experiments, the air controlled expansion and contraction of the parapets, their behavior against wave overtopping and structural stability are investigated.

• Korean journal of applied entomology
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• v.47 no.2
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• pp.141-147
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• 2008

Male adults of bean bug, Riptortus clavatus Thunberg (Heteroptera: Alydidae), release aggregation pheromone (AP) attracting both sexes of adult and nymphs, which its egg parasite, Ooencyrtus nezarae (Hymenoptera: Encyrtidae) exploits the pheromone to find host. The AP consists of three components; (E)-2-hexenyl (Z)-3-hexenoate (E2HZ3H), (E)-2-hexenyl (E)-2-hexenoate (E2HE2H), and tetradecyl isobutyrate (TI). We analyzed composition of the pheromone components of bean bugs from different geo graphical locations of Korea and Japan. The attractiveness of different blends of AP components to R. clavatus was also tested in the fields in Jinju, Korea and in Kumamoto, Japan. Composition ratios (E2HZ3H: E2HE2H:TI) of the AP of Jinju and Iksan populations were 1:1.4:0.2 and 1:0.8:0.2, and those of Tsukuba and Kumamoto populations were 1:2.8:0.2 and 1:1.5:0.1, respectively. In field tests, traps baited with ratio of 1:1:1 (E2HZ3H:E2HE2H:TI=16.7:16.7:16.7mg/rubber septum) and 1:1:0.5(E2HZ3H:E2HE2H:TI= 20:20:10mg/rubber septum) attracted significantly greater number of adult bugs than that of 1:5:1 (E2HZ3H:E2HE2H:TI=7.1:35.7:7.1mg/rubber septum).

• The korean journal of orthodontics
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• v.30 no.4 s.81
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• pp.377-386
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• 2000

At the finishing stage, the use of asymmetric elastics to treat mild skeletal and dental midline discrepancies often creates several side effects such as canted occlusal plane, tipped incisors and unesthetic results. This report presents the clinical cases with midline discrepancies, following a differential diagnosis, optimal mechanics, and considerations in treatment. Differential diagnosis and treatment mechanics with three-piece basal archwire can obtain predictable midline correction with minimal side effects.

• Applied Biological Chemistry
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• v.24 no.1
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• pp.1-6
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• 1981

Studios on the effects of rice straw amendments, soil autoclaving and repeated application related to disappearance of diazinon (diethyl 2-isopropyl -4-methyl -6-pyrimidinyl phosphorothionate) in submerged soils and paddy water were conducted under the laboratory conditions. Degradation of diazinon was slightly accelerated by the amendment of rice straw. The amended soil had 2.4 days shorter half life for diazinon than unamended soil. By autoclaving soils, diazinon degradation was greatly inhibited. The autoclaved soil had about 20 days longer half life for diazinon than the non-autoclaved soil. After repeated application of diazinon granules to the submerged soils, rapid degradation of the insecticide occured in flooded soils and paddy water. The development of diazinon degrading factors in flooded soils and paddy water after repeated application was roughly proportional to the increase of the frequency of diazinon application. By autoclaving soils and paddy water which received repeated application of diazinon, no rapid biodegradation of the insecticide occurred during the 30 days incubation period.

• Korean Journal of Agricultural Science
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• v.3 no.2
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• pp.145-151
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• 1976

This study was conducted to determine the effect of slaked lime and straw used on the soil pH in the flooded condition and yield of rice grown in AKIOCHI paddy field and their residual effects on the rice plants. The results obtained were summarized as follow: when lime and straw were applied, there was on the average 41% of yield increase over plots treated with three elements of chemical fertilizers. When lime plus straw were used, the growth rate at later stage of rice plant was prominent. Damage due to helminthosporium and blast were found less, the rate of lower-leaf death was low, and grain number, per head, filled grain ratio, and weight of rice grain were higher than control. When lime plus straw were used, higher amount of silicate, calcium, nitrogen and potassium was found in the plants at heading stage. The residual effects of lime plus straw were 20% in the first year, about 10% in the second year and 5% in the third year, respectively. Soil pH was affected by both straw and slaked lime, and it was fixed about 8 days after applying in the flooded condition. The following formulae was suggested from the results in the flooded conditions. $$pH=5.5293+8.6007X_1+2.7836X_2-{6.7422X_1}^2-{1.8522X_2}^2-7.000X_1X_2$$ ($X_1$=slaked lime, $X_2$=straw)

• Journal of Wetlands Research
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• v.11 no.3
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• pp.1-8
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• 2009

The groundwater dependent ecosystem associated with a natural stream is the area where mixing and exchange of surface water and groundwater occurs due to large chemical and hydraulic gradients. Surface-groundwater interactions play an important role in biogeochemical processes in groundwater dependent ecosystems and make this area a hydro-ecological hot spot. The objective of this study is to characterize the groundwater dependent ecosystem in a natural stream where nitrate contamination of stream water is observed by means of hydrogeological, chemical, and biological methods. In this study, vertical flow exchange(hyporheic flow) rates between stream and groundwater were estimated based on vertical hydraulic gradients measured at mini-piezometers of various depths. To investigate the biological natural attenuation potential, biological analyses using polymerase chain reaction(PCR)-cloning methods were performed in this study. Results show that the veritical hyporheic water fluxes affect nitrate concentrations and bacterial densities in groundwater dependent ecosystems to some degree. Also, denitrifying bacteria were identified in hyporheic soils, which may support the biodegradation potential of the groundwater dependent ecosystems under certain conditions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.10
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• pp.1611-1618
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• 2005

The microbiological examinations were conducted for the hygienic evaluation on three Korean restaurants during summer season in Busan, Korea. Total one hundred and sixty swabbed samples using sponge were collected from the surface of facilities and utensils at restaurants and total and coliform counts were measured. Also thirty- six air samples were collected at inside of three restaurants for measuring total, coliform, Staphy-lococcus and mold and yeast counts. All collected samples kept in an ice-packed box were transported to the laboratory and analyzed. The results demonstrated that most swabbed samples were highly contaminated with microorganisms and coliforms. The degree of contamination depended on the sampling sites. Averages of total counts of surface swab samples were ranged from not detectable to 2.14$\times\10^{9}$/200 $cm^{2}$, while those of coliforms from not detectable to 8.34$\times\10^{7}$/200 $cm^{2}$/200 $cm^{2}$. Microorganisms also detected from most agar strips of air samples for total, coliform, Staphylococcus and mold and yeast counts. The severely contaminated sites were floor, trench, water bottle, plastic drainer, rubber gloves, shelves, and unsealed wet towel. Those sites should be focused and controlled according to control Points of sanitation standard operating Procedures. Also, periodic microbiological examination in addition to visual examination should be applied on those highly contaminated sites for reducing risk of foodborne disease outbreak at restaurants

• Journal of dental hygiene science
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• v.9 no.1
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• pp.121-127
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• 2009

A comparative analysis was conducted through this study on tooth brushing and a use of auxiliary oral hygiene devices for oral hygiene for 287 S Health College students some of whom major dental hygiene and some of whom don't relate to the department, and then has drawn out the results as below. 1. Relating to the frequency of tooth brushing, 2-3 times a day was the utmost case in both departments(p < 0.05). 2. In use of toothbrush bristle, the students of dental hygiene department used medium bristle(51.2%), while the student of other department used soft bristle(51.5%)(p > 0.05). 3. In the term of tooth brush used, 2~5 months was the utmost case in both departments(p > 0.05). 4. In tooth- brushing method, all the student of both departments said they knew how to do it(p > 0.05). 5. In the acquisition of tooth brushing methods, the students of dental hygiene acquired it from dentistry 44.4%, and the students of other department from TV or Radio 47.5% (p > 0.05)which was a quite high rate. 6. In reference to recognition level on auxiliary oral hygiene devices, dental hygiene students said Yes 79.8%, and the other side students said No 63.9%(p < 0.05). In reuse of auxiliary oral hygiene devices, a great number of students of both departments said No (p < 0.05). 8. In reference to the chance to use auxiliary oral hygiene devices, 58.1% of dental hygiene students chose them with their own judgement, and 37.8% of other department students recommended by dentist's offices(p < 0.05). 9. Relating to the reason for not using auxiliary oral hygiene devices, 38.9% of the dental hygiene students said it's bothersome, and 56.7% of the other department students said they didn't know about these things(p < 0.05). 10. In the recognition level of dental floss, in knowing the way to use it, whether or not of using it, the students of both department showed a significant difference (p < 0.05). 11. In the recognition level of floss holder and the yes or not of using it, there was an insignificant difference(p > 0.05), while in understanding of it, there was a significant difference(p < 0.05). 12. Relating to the recognition level of electric tooth brush, yes or no of using it, there wasn't a significant difference(p > 0.05). 13. In the cognition level of rubber stimulator, yes or no of using it, there wasn't much difference, while in understanding to use it, there was a significant difference(p < 0.05). 14. In the understanding level of water pik, yes or not of using it, there wasn't a great deal of difference(p < 0.05), but in inquiry of whether or not of using it, there was no difference (p > 0.05), 15. In the understanding level of tongue scraper, whether or not of using it, there wasn't much difference(p > 0.05), but in understanding to use it, there was a great deal of difference(p < 0.05). 16. In the recognition of garglin, understanding of it, and whether or not of using it, the two departments didn't show a significant difference(p < 0.05).