• Journal of Periodontal and Implant Science
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• v.23 no.3
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• pp.493-506
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• 1993

For maintenance of an ailing or failed implant it is essential to treat the implant fixture surface so as to remove bacterial endotoxin and make a surface tolerated by surrounding soft and hard tissue. Thus in this study the method that makes the smoothest surface treated with a high speed diamond bur, a low speed diamond bur, a stone, a rubber point or Jetpolisher was studied. With the profilomenter a mean value of $R_{max}$ was measured. The hight speed diamond, the rubber point and the Jetpolisher showed a mean $R_{max}\;7.77{\mu}m$. The low speed diamond bur, the rubber, point and the Jetolisher made a mean value of $R_{max}\;8.44{\mu}m$. The stone, the rubber point and the Jetolisher showed the smoothest surfaces with a mean value of $R_{max}\;6.24{\mu}m$. TPS (titanium plasma sprayed) areas showed a mean vlaue of $R_{max}\;24.42{\mu}m$, and the smooth surfaced titanium disc manufactured by the company (IMZ, Germany) shows a mean value of $R_{max}\;3.00{\mu}m$. Under the SEM examination the disc treated with a high speed diamond bur, a rubber point and a Jetpolisher showed partially remaining TPS particles, but the height of these particles were reduced remarkably compared with those of the original TPS. The disc treated with a low speed diamond bur, a rubber point and a Jetpolisher showed a rough topography with remaining TPS on the entire surface. A stone, a rubber point and a Jetpolisher removed almost TPS and the bulk titanium metal was exposed and some scratches were made by the stone. All treated discs were revealed as rougher than the smooth surface disc manufactured by the company. An untreated TPS disc shows a very irregular surface and a $40{\mu}m$ height of the plasma sprayed areas.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.5
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• pp.583-590
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• 2015

Submarine cable installation is essentials for grid connection between existing power grid and newly produced electricity which will be from offshore wind farm in Southwest sea area of Korea. Especially, submarine cable route and protection method is designed in order to ensure the economical efficiency, workability and stability of submarine cable installation. On this paper, we will give the basic information about the submarine cable route and protection method of offshore wind farm which will be built in Southwest sea area of Korea. For this, we have a numerical simulation at high and low tide based on the third-generation wave model SWAN(Simulating WAves Nearshore) using the long term wave data from Korea Institute of Ocean Science and Technology(KIOST). The results of the study, year mean Hs is 1.03m, Tz is 4.47s and dominant wave direction is NW and SSW When the incident wave direction is NW(Hs: 7.0 m, Tp: 11.76s), the distribution of shallow water design wave height Hs was calculated about 4.0~5.0m at high tide and 2.0~3.0m at low tide. When the incident wave direction is SSW(Hs: 5.84 m, Tp: 11.15s), the distribution of shallow water design wave height Hs was calculated about 3.5~4.5m at high tide and 1.5~2.5m at low tide. The wave direction on a dominant influence in the section of longitude UTM 249749~251349(about 1.6 km) and UTM 251549~267749(about 16.2 km) in the submarine cable route are each NW and SSW. Prominently, wave focusing phenomenon appears between Wi-do and Hawangdeung-do, in this sea area is showing a relatively high wave hight than the surrounding sea areas.

• Food Science and Preservation
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• v.24 no.6
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• pp.802-812
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• 2017

This study was conducted to investigate the quality properties depending on the cultivation methods (general, organic, pesticide-free) of yuza and its various parts (peel, pulp, seed). The contents of hesperidin were the highest in yuza feel grown by pesticide-free method (13.23 mg/g). The contents of naringin presented a higher content in the peel, especially which of the general (4.62 mg/g) showed the highest value. Vitamin C analysis showed the highest content in the peel, significantly varied according to the cultivation method and various parts (p<0.05). Vitamin C value was significantly highest in organic peel, which was 770.02 mg/100 g, whereas among the peel, the pulp and the seed were it the lowest in the seed. The content of total polyphenols were the highest in general peel (0.85 mg/g). Flavonoid content of pesticide-free seed was significantly higher than those of the other yuja samples which was 0.89 mg/g (p<0.05). The DPPH radical scavenging activity was relatively more active in the peel among the above-mentioned three parts, especially the pesticide-free peel was most active, which was 73.94%. The ABTS radical scavenging activity of organic peel was significantly active among the samples, which was 84.47% (p<0.05). Based on these results, it can be said that yuja has variety of useful components in the pulp and the seed as well as the peel: and thus it's hight recommended to develop more varied yuja products.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.5
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• pp.292-297
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• 2006

A research was carried out to investigate the release pattern of slow release nitrogen fertilizer compound(SRNC) that is latex coated urea(LCU) and to recommend the application rate of the fertilizer at dry seeding rice culture in Honam plain area. The experiment was conducted at experimental field(Jeonbug series, fine silty, mixed, nonacid, mesic family of Fluvaquentic Endoaquepts) of National Honam Agricultural Research Institute. A medium late maturing rice variety (Dongjinbyeo) was seeded at the rate of $60kg\;ha^{-1}$ by drill seeder on April 1, 1997 and March 30, 1998. Fertilizer application rate was $160-90-110kg\;ha^{-1}$ for $N-P_2O_5-K_2O$. Soil ammonium nitrate($NH_4-N$) contents remained higher in all SRNC plots than conventional ones and higher with the increase of SRNC application rate until panicle formation stage, but the contents was higher in the conventional than NRNC plots at the heading stage. The plant hight was taller in SRNC than conventional plots until maximum tiller stage, but became similar in both conventional and SRNC plots at heading stage. The culm and panicle number was greater in SRNC than conventional plots throughout all growth stage, but the effective tiller rate was higher in conventional ones. Nitrogen efficiency was higher in the SRNC than conventional plots, but the efficiency was decreasing with the higher SRNC level. The spikelet number per unit area was greater in SRNC than conventional plots, and increased with higher SRNC level. The more spikelet number with higher NRNC level resulted in lower 1,000-grain weight. The rice yield in conventional plot was similar with only 60% SRNC level, but lower than 80% and 100% SRNC levels. However, slight lodging was observed in 100% SRNC level. In conclusions, we recommend NRNC application level as 80% of standard nitrogen application for early dry seeding culture of rice Honam plain area.

• Journal of agriculture & life science
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• v.45 no.6
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• pp.9-19
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• 2011

This study aimed to investigate the effect of night temperature on tomato and grafted watermelon seedlings, particularly, shoot height, leaf area, stem diameter, and total dry weight and relationship among the growth parameters which are used to evaluate healthy seedling. Plants were grown at 10, 15, and $20^{\circ}C$. Leaf area index (LAI) and total dry weight of tomato seedlings weight deceased more significantly under $10^{\circ}C$ than other night temperature regimes. In grafted watermelon seedlings, shoot height increased shapely and stem diameter decreased under $20^{\circ}C$. Increasing the integral temperature, leaf area of tomato seedlings under $10^{\circ}C$ decreased and shoot height of grafted watermelon seedlings increased although temperature integrals are same. The relationships among the growth parameter were changed upon the night temperature. Stem diameters of tomato seedlings had upward tendency with increase of shoot height, but there were no significant differences among night temperature regimes. Shoot hight of grafted watermelon seedlings had no relationship with shoot height. These results indicate that shoot height and stem diameter of tomato seedlings is not appropriate for assessing seedlings quality but shoot height of grafted watermelon seedlings with stem diameter is available.

• Korean Journal of Social Welfare Studies
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• v.44 no.3
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• pp.85-112
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• 2013

This study aims to understand the developmental trajectories of life satisfaction among retirees and to examine what factors differentiate different trajectory classes. This study used three waves of longitudinal data from Korean Retirement and Income Study and data collected every two years(2005, 2007, and 2009). Subjects were respondents aged 50-69 who identified to be retired between wave 1 and wave 2. Finally, this study used 243 respondents for final data analysis. Life satisfaction was measured by seven items. The latent class growth model and multiple logistic regression model were used for data analysis. This study identified three distinct trajectory classes: high stable class(47.7%), high at the early stage but decreased class(42.8%), and low at the early stage and then decreased class(9.5%). This study founded that approximately 50% of the retirees experienced the decline of life satisfaction after retirement and about 10% of the sample was the most vulnerable group. This study analyzed what factors make different among the distinct trajectory groups. As a results, retirees who experienced the improvement in health change were more likely to be in 'high stable class' compared to 'hight at the early stage but decreased class'. In addition, retirees who were less educated, maintained the same health status rather than the improvement, worked as a temporary or a day laborer, and had less household income were more likely to belong to 'low at the early stage and then decreased class' relative to 'high stable class'. This study suggests that there are distinct three trajectories on life satisfaction among the retirees and finds out factors differentiating between trajectory groups. Based on these findings, the study discusses the implications for social work practice and further study.

• Korean Journal of Heritage: History & Science
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• v.51 no.3
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• pp.72-87
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• 2018

This study highlights a drainage gate and a ditch, which existed around the whole area of the western shore of Wolji Pond(月池) and focuses on a possible connection between the drainage facility on the western shore and the historical drainage system of Wolji Pond. Specifically, it primarily considered locations and the form of a drainage gate, the relationship between northwestern ditch of Wolji Pond and the drainage gate, and the establishment period and the character of the drainage facility on the western shore. The drainage gate found in excavation in 1975 is determined as the same facility as Surakgu(水落口) recorded on an actual measurement drawing, 1922. Therefore, it is highly probable that there were already the drainage facility in the western shore of Wolji Pond before the 1920s. The drainage gate constructed by processing rectangular stones has four drainage holes for controlling water level. The way of the drainage through the drainage holes is the same as that of the northern shore of Wolji Pond. From a cadastral map drawn in 1913, it is found that the ditch existed in northwest of Wolji Pond. The ditch was proximate to the drainage gate and shared the same axes. Hence, the ditch and the drainage gate are determined as a organic facility connected to the drainage system of Wolji Pond. In particular, the ditch existed in northwest of Wolji Pond is the basis for judging that the drainage facility in the western shore were established before the 1910s. Water flowed in through drainage holes of the drainage gate is drained into the northwest of Wolji Pond, through the ditch. The establishment period and the intention of the drainage facility on the western shore can be interpreted in two aspects. First, they might be 'a agricultural irrigation facility in the Joseon era', given that Wolji Pond was recorded as a agricultural reservoir, and that the whole northwestern area of Wolji Pond was used as farm land areas. Second, they might be 'a drainage facility for controlling the water level in creating Wolji Pond', given that the drainage gate was annexed to the lower shore forming the waterline of Wolji Pond, and that the hight of drainage holes on top of the drainage gate was similar to the full water level of Wolji Pond. Considering the related grounds and circumstance, the latter possibility is high.

• Korean Journal of Heritage: History & Science
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• v.46 no.1
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• pp.318-345
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• 2013

This study was carried out with a focus on the factor on the periodical space organization of Daebodan (大報壇: the altar of great recompense) in Changdeok Palace, which is significant in terms of political history in the late Chosun Dynasty, and consider the factors in the formation of the structural system through historical records and drawings. Daebodan has the ideology of righteousness to the Ming Dynasty which the hierarchy of the Joseon Dynasty. who felt the crisis of the domination order, imposed as a solution after the Manchu war of 1636. In addition, Daebodan was built by complex factors that entailed the self-esteem of the 'Joseon Centralism Ideology (朝鮮中華)' and the desire of the sacrificial rituals for Heaven that were imminent to the kings of Joseon. Superficially, Daebodan has the spatial organization of the Sajik (社稷) Altar and the placement of an annex building, but had the applied placement due to limited topography and access to the backyard. Furthermore, the lateral structure of Daebodan multiply accepted various factors of the nine step's stairs, the hight of five cheok (尺), the circumstance of two floors that were showed in the altar and platform with small fences and an imperial order including the internal form of Hwangjangbang (黃帳房). Moreover, the name of the alter came from 'the Jiaote Sheng Book of Rites(禮記 郊特牲)' representing 'the suburban sacrifice ritual for Heaven (郊天)', and it was built by not only combining the system of the Sajik Altar in the Joseon Dynasty and China but also avoiding 'excessive etiquette (僭禮).' The point is a remarkable feature shown by the structural system of Daebodan. Thus, it is considered that the 'Notion of Confucian-Cultural Succession (中華繼承意識)' and the desire of the sacrificial rituals for Heaven were expressed by the structure and form of altar. This study examined the process of the creation, expansion, decline and disposal of Daebodan in a chronological order, and found that the ruling ideology of the governing elite by the political and cultural background of the era at each transitional point was reflected in the spatial formation of the altar. On the other hand, as a result of performing a field survey to find the location in accordance with Daebodan in drawing materials, there remains items such as worked stones from Daebodan, precast pavers and fragments of proof tile discovered in the surrounding of tora vine (Actinidia arguta) which is a natural monument of Changdeok Palace. As such, verification through future excavation and investigation is required.

• Journal of Aquaculture
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• v.21 no.4
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• pp.203-212
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• 2008

A nutritional demand of oyster, Crassostrea gigas larva as part of research for improving of utilization of microalgae being used for the artificial oyster seed production. The change of body growth and biochemical compositions of larvae were investigated during larvae rearing in hatchery. The larvae were cultured in 60 M/T tank and fed mixture 6 different phytoplankton species, Isochrysis galbana (30%), Cheatoceros gracilis (20%), Pavlova lutheri (20%), Phaeodactylum triconutum (10%), Nannochryis oculata (10%) and Tetraselmis tetrathele (10%). The initial feeding amount was $0.3{\times}10^4cells/mL$ at three times a day to D-shaped larva and the feeding amount had been increased 30% gradually every two day since the larvae were raising. The larvae were developed from D shape to pediveliger stage for 12 days. The daily growth of shell length and hight were $5.8{\sim}30.8\;{\mu}m$ and $8.7{\sim}31.4\;{\mu}m$, respectively and weight gains were changed from D shape to pediveliger as follow: wet weight was $0.52{\sim}15.0\;{\mu}g/larva$, dry weight was $0.2{\sim}6.5\;{\mu}g/larva$, and ash free dry weight was $0.1{\sim}8.5\;{\mu}g/larva$. The larvae growth pattern shown a logarithmic phase from D shape to umbone stage but after that stage shown a exponential growth aspect. The crude protein, crude lipid and nitrogen free extract (NFE) of larvae during rearing periods were analyzed as $6.1{\sim}10.6%$, $0.6{\sim}1.1%$ and 1.0-2.7%, respectively. And the total amino acid contents of the larvae during rearing periods were in order as glutamic acid $1.26{\sim}2.24%$, aspartic acid $0.97{\sim}1.70%$, and methionine $0.12{\sim}0.33%$. Of the total fatty acid in the analyzed larvae, the saturated fatty acid (SSAFA) was decreased from 54.3% (D shaped larvae) to 17.1 % (pediveliger) as larvae development but the total mono-unsaturated fatty acid (${\Sigma}MOFA$) and Poly-unsaturated fatty acid (${\Sigma}PUFA$) were increased from 29.9% and 7.8% to 40.6% and 45.6%, respectively. By the way the each fatty acid of the larvae were composed of palmitic acid $9.89{\sim}36.95%$, oleic acid $12.17{\sim}32.29%$, linoleic acid $1.96{\sim}33.55%$, EPA $2.17{\sim}11.58%$ and DHA $1.95{\sim}4.51%$. As a result of this study, the larvae of oyster were demanded a various nutrients for healthy growth and the feeding control, expecially after umbone stage larvae are a rapidly growing time, is very important for success of artificial seed production.

• Journal of the Korean Society of School Health
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• v.8 no.2
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• pp.219-232
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• 1995

This study was conducted to examine both usage rate of standard sized desks and chairs for the middle and high school students and pain complant of students who use standard-size desk & chair in Taegu, Korea, by means of questionnaires with 1,201 students of both male and female middle and high schools in Taegu area from March 20 to April 19, 1995. The result of this study is summarized as follows. It was mostly shown that the desks and chairs used by those middle and high school students were 1-3 higher than their standard sizes, and that they also preferred a little higher size with respect to their desired sizes. The rate of students who use the standard size showed that the desk accounted for 30.5%, and chair for 21.0%, that the size bigger than the standard accounted for 61.3%, respectively, and 65.2, and that the size smaller than the standard accounted for 8.2%, respectively, and 13.8%. The using rate of the standard sized for the middle school students indicated that their desk accounted for 44.1%, and their chair for 26.0% which were higher than 16.1% and 14.7% for the high school students. Then, the rate of the male students indicated that their desk accounted for 31.5% and their chair for 24.5% which were higher than 29.6% and 17.6% of the female students. In addition, the using rate of the standard size for the public schools showed that the desk accounted for 34.2% and chair for 24.5% which were also higher than 27.1% and 17.5% of the private schools. It was shown, however, that the using rate of the standard size for both groups was lower. The most inconvenient factor in the usage of their desks appeared in such orders as their wear, narrow drawers, too low height and uneven face, while the factor in their chairs did in such orders as too hard chair body the surface and back part, wear, lower and higher height and narrow width. Their physical pains resulting from usage of those desks and chairs showed that the male and female middle school students' complaint rate of pains in their neck and shoulder accounted for 32.1%, respectively, and 36.0% which were highest, while those high school students' complaint rate in their waist accounted for 37.9%, respectively, and 44.1% which were hight. It was also shown that the bigger their height, the higher their complaint rate of pain in the waist, and that their complaint rate in the shoulder and neck was totally higher. When using the standard-sized desks and chairs, their complaint rate of pain in the shoulder and neck accounted for 25.4%, respectively, and 23.8%. As compared with them, when using the desks or chairs bigger than the standard size, their complaint rate accounted for 31.5%, respectively, and 31.8% which were high while it did 26.5% and 28.9% when using them smaller than the standard size which were also high, the usage of those standard-sized desks and chairs indicated lower complaint rate of pain in their waist than used the desks and chairs bigger or smaller than the standard size. The rate of the middle and high school students who use their standard size is very low and the size of their desks and chairs are quite different from those they hope to use and many students appeal their discomfort with their desks and chairs. Therefore, the school should try to provide the desks and chairs of the various students' standard sizes in consideration of their physical condition and it also should try to get extra desks and chairs of various sizes according to the students' standard size and their preference.