• The Journal of the Petrological Society of Korea
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• v.28 no.2
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• pp.111-128
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• 2019

Ulleung Island is the top of an intraplate alkalic volcano rising 3200 m from sea floor in the East Sea (or Sea of Japan). The emergent 984.6 m consist of eruptive products of basaltic, trachytic and phonolitic magmas, which are divided into Dodong Basaltic Rocks, and Ulleung, Seonginbong and Nari groups. The Maljandeung Tuff in the Nari Group consists of thick pyroclastic sequences which are subdivided into 4 members (N-5, U-4, 3, 2), generating from explosive eruptions during past 18.8~5.6 ka B.P. From chemical data, the Member N-5, phonolitic in composition, is considerably enriched in incompatible elements and REE patterns with significant negative Eu anomalies. The members 4, 3 and 2 are phonolitic to tephriphonolitic in composition, and their REE patterns do not have significant Eu anomalies. In variation trend diagrams, many elements show abrupt compositional gaps between members, and gradual upward-mafic variations from phonolite to tephriphonolite within each member. It suggests a downward-mafic zonation that were evolved into phonolitic zone in the lower part to tephriphonolitic zone in upper part of magma chamber. It is supposed that the chemical stratification generated from multiple mechanisms of thermal gravidiffusion, crystal fractionation, and gradual melting and sequential emplacement. The stratified magmas were explosively erupted to generate a small caldera during short period (11 ka B.P.). Especially both members (U-3, 2) were accumulated by gradually erupting from the upper phonoltic zone to the lower tephriphonoltic zone of the stratified chamber in 8.4 ka B.P. and 5.6 ka B.P. time, respectively.

• Journal of Practical Agriculture & Fisheries Research
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• v.20 no.1
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• pp.163-174
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• 2018

Rice cultivation is immensely affected by many climatic factors including temperature, precipitation, etc, and imbalanced climatic conditions negatively affect the growth of rice. In this study, we investigated the effects of different agroclimatic zones of Chungnam Province on rice quality and examined the correlations between climatic characteristics and rice yield components. Average temperatures and rainfall were higher in 'Western Sobaek Inland' than those in the 'South Western coastal zone, and precipitation records showed a wide variation among counties due to typhoons during the examined periods. The average accumulative temperature affecting the magnitude of production during reproductive growth periods was higher in "Cheon-An", "Gong-Ju", "Yeon-Gi (Se-Jong)", "Bo-Ryeong", and "Dang-Jin" counties than those in other counties. The plant height was higher in 'Western Sobaek Inland' counties such as "Yeon-Gi(Se-Jong)" and "Cheon-An", and 'Southern Charyeong Plain' counties such as "Cheong-Yang", "Dang-Jin", and "A-San", than those in other counties. The number of tillers during the 40 days after rice transplantation in "Seo-Cheon" and "Bo-Ryeong" counties increased compared to other counties. This result was relevant to the fact that the date of rice transplantation in those counties was 3 to 4 days later than those in other counties of Chung-Nam Province. The average yield (milled rice basis) was the highest in 'Western Sobaek Inland' zone, showing 3,756 kg ha^-1, followed by 'Southern Charyeong Plain' zone showing 3,621kg ha^-1, and was the lowest in 'South Western coastal zone by 3,315kg ha^-1. "Yeon-Gi(Se-Jong)" and "Dang-Jin" counties showed the highest yields of 4,100kg ha^-1. "Seo-San", "Seo-Cheon", and "Tae-An" counties were relatively lower yields of 3,240~3,280kg ha^-1 in comparison of other counties.

• The korean journal of orthodontics
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• v.25 no.3 s.50
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• pp.235-245
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• 1995

The purpose of this paper is to review two recently reported, long-term studies of several chemical methods to control gingivitis and decalcification in adolescent orthodontic patients. The first study(gingivitis study) was designed to determine whether conventional toothbrushing and twice daily use of a brush-on 0.4 per cent $SnF_2$ gel containing more than 90 per cent available $Sn^{2+}$ would be more effective for controlling plaque accumulation and gingivitis in the presence of orthodontic appliances than conventional toothbrushing alone. The second study(decalcification study) was designed to compare the effectiveness of controlling decalcification in orthodontic patients with either a II00 ppm F tooth paste used alone, this same toothpaste and a 0.05 percent NaF rinse or this toothpaste and a 0.4 percent $SnF_2$ gel. In the gingivitis study, sixty-five consecutively treated adolescents who were to receive full-mouth fixed orthodontic appliances were assigned to two groups according to age and sex criteria. In the decalcification study an additional 30 subjects(95 total) were similarly assigned to a third group. The first group(control, n=35) used only toothbrushing with a standard fluoride(1100 ppm F) toothpaste. The second group used toothbrushing with a similar dentifrice supplemented with a 0.4 percent $SnF_2$ gel($SnF_2$ gel group, n=30) used twice daily for the entire 18-month study period. The third group(in the decalcification study only) used a similar toothpaste and 0.05 percent NaF rinse(NgF rinse group, n=30). Clinical assessments of plaque accumulation using the Plaque Index, gingival inflammation using the Gingival Index, and coronal staining were completed single-blinded before appliances were placed and 1, 3, 6, 9, 12 and 18 months after appliances were placed. Decalcification was assessed single blind on all labial surfaces of all erupted teeth before appliances were placed and 3 months after appliances were removed. The results of the gingivitis study indicated that the $SnF_2$ gel gorup had significantly lower scores for the Plaque Index(p<0.01) and Gingival Index(p<0.001) at all examinations during orthodontic treatment than did the control group. In the $SnF_2$ gel group, one subject developed mild coronal staining and two subjects developed moderate staining. In the decalcification study, when pre-treatment levels of decalcification were subtracted from post-treatment values, significantly lower decalcification scores(p<0.05) were found for both whole mouth and first molars in the NaF rinse and gel groups as compared with the control gorup(toothpaste alone). Although the gel group consistently had less decalcification than the rinse group, this difference only approached statistical significance.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.4
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• pp.380-389
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• 2007

Stable carbon and nitrogen isotopes were analyzed in suspended particulate organic matter, macroalgae and macrobenthic invertebrates in order to determine the importance of primary organic matter sources in supporting food webs of rocky subtidal and intertidal macroalgal beds in the Korean coasts. Investigations were conducted at the inter tidal sites within Gwangyang bay, a semi-enclosed and eutrophicated bay, and the subtidal sites of the east coast, a relatively oligotrophic and open environment, in May and June 2005. Water-column suspension feeders showed more negative $\delta^{13}C$ values than those of the other feeding guilds, indicating trophic linkage with phytoplankton and thereby association with pelagic food chains. In contrast, animals of the other feeding guilds, including interface suspension feeders, herbivores, deposit feeders, omnivores and predators, displayed relatively less negative $\delta^{13}C$ values than those of the water-column suspension feeders and similar with that of macroalgae, indicating exclusive use of macroalgae-derived organic matter and association with benthic food chains. Most the macrobenthic species were considered to form strong trophic links with benthic food chains. In addition, the distribution of higher $\delta^{15}N$ values in macrobenthic consumers and macroalgae at the intertidal sites of Gwangyang Bay than those at the subtidal sites of the east coast suggests that anthropogenic nutrients may enhance the macroalgal production at the intertidal sites and in turn be incorporated into the particular littoral food web in Gwangyag Bay. These results confirm the dominant role of macroalgae in supporting rocky subtidal and intertidal food webs in the Korean coasts.

• Journal of dental hygiene science
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• v.12 no.2
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• pp.103-108
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• 2012

A study was designed to evaluate the level of moral development in 450 pre-dental professionals of 2 educational institution in Jeollabukdo, Ik san city. Data were collected through self-reported questionnaires from October 2010. The Korean version of the DIT(Defining Issues Test) was adopted to evaluate level of moral development with the score of P(%) and stage. The data were analyzed by descriptive statistics, t-test, one-way ANOVA and Pearson's correlation coefficient. The mean scores of P(%) was 43.10 in dental students and 41.21 in dental hygiene students(p=0.190). The score of stage 5A was highest which was followed by S3, S4, S6, S5B, S2. The score of stage 5B and 6 revealed sigificant difference by groups. The score of stage 6 revealed significant difference by sex in dental students(p=0.003). In dental hygiene students, it's significant difference by religion(S5B, p=0.044), birth order(S2, p=0.027) and growth area(S4, p=0.015). As for the correlations between moral development and the score of the stage, the score of P(%) was negatively correlated with the scores of stage 2, 3, 4 and 5B. On the other hand, the score of P(%) was positively correlated with the scores of stage 5A and 6. In conclusion, for enhancing dental students' moral development it is necessary a systemic ethics education and program development in curriculum.

• Restorative Dentistry and Endodontics
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• v.31 no.2
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• pp.113-118
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• 2006

The aim of this study was to evaluate the ability of newly marketed NRT instruments to maintain the original root canal configuration and curvature during preparation in comparison with the three existing instruments in simulated root canals. Simulated canals in resin blocks were prepared with ProFile. K3, ProTaper and NRT instrument (n = 10 canals in each case). Pre- and post-operative images were recorded, and assessment of canal shape was completed with a computer image analysis program. The data were analyzed statistically using the One-way ANOVA followed by Duncan s test. The ability or instruments to remain centered in prepared canals at 1-, 2-mm levels was significantly better in ProFile groups than in other groups (p < 0.05). The change of centering ratio in NRT groups at 5-mm level was significantly greater than ProFile group and at 6- and 7-mm level than all other groups (p < 0.05). Although the NRT system was comparable to other systems in regards to its ability to maintain the canal configuration of apical portion, this system was more influenced by the mid-root curvature due to its stainless-steel files for coronal preflaring.

• Magazine of the Korean Society of Agricultural Engineers
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• v.18 no.2
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• pp.4089-4095
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• 1976

The safety of shore structure including the sea dipe is largely affected by typhoon. Accordingly it is desirable to analize the typhoon and determine the wind direction and velocity for use in planning and design of the structure. This method was adopted for the design of the Yong San Gang Estuary Dam. A comparative study of the results of typhoon analysis with the meteorological data obtained through actual observation is summarized as follows; (1) 62% of the typhoons occur during May to June in a year, and 62% of the typhoons which have an influence on the Korean peninsula, especially the proposed estuary dam fsite, proceed eastward through the zone in lat. 36$^{\circ}$-37$^{\circ}$N. Such typhoons occur two to three times a year on the average. (2) Data on typhoon "SARL" were used as a model case in designing the estuary dam, where it was proved that a southwesterly wind had a maximum velocity of 30m/sec in case r=150km, ${\alpha}$=120$^{\circ}$. Within the range of 22$^{\circ}$30'on the right and left side of the fetch line of the estuary dam, the wind direction varied SSW\longrightarrowSW\longrightarrowWSW, and the wind velocity varied 29m/sec\longrightarrow30m/sec\longrightarrow125m/sec. Such phenomemum lasted for five hours. (3) An analysis of data obtained during 44 years at Mok Po Meteorological Station shows that a wind with a velocity of some 25m/sec occurred twelve times in the S-direction and two times in the SW-direction, while that with a velocity of 30m/sec occurred three times in the S-direction, three times in the SSW-direction and one time in the SW-direction. The wind which had an influence on the estuary dam had a direction of SSW\longrightarrowSW\longrightarrowWSW and a velocity of min. 30m/sec. Actually, a wind with a max. velocity of 31.3m/sec occurred in the SSW-direction on March 15 and 16, 1956 where the mean velocity during two hours was 28m/sec and that during four hours was 24.6m/sec. (4) The data obtained through actual observation show that when the velocity is low, the wind with a fixed direction lasts long, and when the velocity is high, it is short-lived. It is difficult to determine the velocity of a wind which blows in a fixed direction for consecutive two or four hours. Therefore, the values obtained through typhoon analysis are larger that those obtained through actual observation, and hence, it is resonable to use the analyzed valuse for design of the estuary dam and shore structures. (5) The greatest effect was had on the estuary dam when typhoon was proceeding at a velocity of 29.71m/sec in the direction of ${\alpha}$=120$^{\circ}$(SW) at a point of R=150km from the center of the typhoon.

• Journal of the Korean Applied Science and Technology
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• v.30 no.4
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• pp.635-648
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• 2013

This study was carried out to investigate the emulsifying properties of surface-active substances from defatted rapeseed cake by supercritical $CO_2$ extraction. Based on the interfacial tension data, a supercritical fluid extract (SFE) with the lowest value of 14.16 mN/m was chosen for evaluation which was obtained from No. 2 extraction condition (150 bar, $65^{\circ}C$, 250 g). For emulsions with SFE, some physicochemical properties (i.e., fat globule size, creaming stability, zeta potential etc) were investigated according to changes in SFE concentration, pH, and NaCl addition in an emulsion. It was found that fat globule size was decreased with increasing SFE concentration in emulsion, with showing a critical value at 0.5 wt%, thereby resulting in less susceptibility to creaming behavior. The SFE emulsion also showed instability at acidic conditions (pH<7.0) as well as by NaCl addition. This was coincided with zeta potential data of emulsion. In addition, SSL (sodium stearoyl lactylate) found to be suitable as a co-surfactant, as it helped considerably in decreasing fat globule size in emulsions and its optimum concentration to be over 0.03 wt%, based on 0.1 wt% SFE in emulsion.

• Korean Journal of Agricultural Science
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• v.3 no.2
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• pp.139-144
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• 1976

To deter-mine the most reasonable method for improving of newly reclaimed soil, seven kinds of improving methods were tested and the soybean was cultivated as test crop. The results obtained are summarized as follow: The newly reclaimed soil where this experiment was carried out showed low acidity and was deficient in the humus, the phosphate, the calcium and the magnesium. Both the fused phosphate as well as the calcium was much effective to the correction of the soil acidity. The compost was the most effective source to increase the content of the humus in the soil, and also the calcium application showed a significant effect to increase the amount of humus. Not only compost but also fused phosphate were much effective to increase the content of calcium in the soil. Each factor as the calcium, the fused phosphate, the compost and the deep plowing has an effect to increase the amount of magnesium in soil significantly. The compost increased the potassium in soil. The amount of magnesium in soybean plant was significantly increased by the application of the calcium, the fused phosphate or the compost. And the calcium and the fused phosphate had an effect to increase the grain yield of soybean. The highest grain yield of soybean was taken at the treatment of N.P.K.+Compost+Calcium+Deep-plowing. The grain yield of soybean was significantly correlated with the soil acidity, the amount of the humus and the magnesium in soil and the amount of the magnesium in soybean plant.

• Journal of Korean Society of Forest Science
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• v.101 no.2
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• pp.195-202
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• 2012

Three-season field study was conducted to investigate the distribution of monoterpene(10) and air anion in ambient air at five forests. ${\alpha}$-Pinene, camphene, sabinene, ${\beta}$-pinene, myrcene, terpinolene, limonene, 1,8-cineol, linalool, and camphor were quantified in the samples collected. The highest 4-hour mean concentration of total monoterpene were ${\beta}$-pinene+myrcene as 958 pptv at Juknokwon dominated by bamboo and ${\alpha}$-pinene (524 pptv), limonene (445 pptv) at Wood Land and Suncheon Bay, respectively. The seasonal means were observed to peak during spring with their maximum at Wood Land and Seonam Temple and during summer at Juknokwon and Suncheon Bay. The 24 hour concentration mean of atmosphere standards were found with much lower values than those by law. The highest concentrations of air anion were measured $400{\sim}3,000ea{\cdot}mL^{-1}$ through the sites. There is no significant correlation between the concentration of monoterpene and air anion.