• Environmental Mutagens and Carcinogens
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• v.22 no.4
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• pp.296-302
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• 2002

In recent years, the safety of sunscreens have been challenged based on the reports of its adverse effects on users; dermatitis, allergic contact dermatitis, photoallergic contact dermatitis. In the toxicological aspect, the need to investigate the safety of sunscreens is steadily increasing. However, there were few studies on the correlation between sun protection factor (SPF) and the safety of sunscreens. The objective of this study was to assess whether there was a correlation between SPF and the skin irritation index of sunscreens. Octyl methoxycinnamate (OMC) was selected, which was the most frequently used (about 92% in korea and about 90% in the world) in sunscreens. In vitro SPF test was performed using the standard samples recommended by KFDA guideline. We examined primary and cumulative skin irritation and eye irritation of OMC standard sample as well as homosalate. As in vitro SPF was increased, skin irritation index was increased in primary skin irritation test ($r^2$=0.986) and cumulative skin irritation test ($r^2$=0.939). In addition, OMC was non-irritating and non-sensitizing. In this results, there was a good correlation between SPF index and skin irritation index.

• Ocean and Polar Research
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• v.33 no.spc3
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• pp.325-336
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• 2011

Seasonal to inter-annual variations of water properties in the western channel of the Korea Strait are investigated using quasi-monthly hydrographic observations collected during 2006-2010. Weak vertical temperature and salinity gradients are observed during the winter months and these remain until May. At the upper layer, temperature increases from March and reaches a maximum in August, while salinity decreases during the same period. Near-bottom water shows low temperatures during late winter and fall with a minimum peak in September. Korea Strait Bottom Cold Water produces thick layers (>20 m) in 2006 and 2010, while it is observed very near the bottom with relatively high temperature in 2008 and 2009.

• Journal of the Korean Society for Advanced Composite Structures
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• v.4 no.4
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• pp.1-8
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• 2013

Pile foundations constructed by the fiber reinforced polymer plastic piles have been used in coastal and oceanic regions in many countries. Generally, fiber reinforced polymer plastic piles are consisted of filament winding FRP which is used to wrap the outside of concrete pile to increase the axial load carrying capacity or pultruded FRP which is located in the core concrete to resist the bending moment arising due to eccentric loading. In this paper, the analytical procedures of hybrid concrete filled FRP tube flexural members are suggested based on the CFT design method. Moreover, the analytical results are compared with the experimental results to obtained by the previous researches. The results of comparison analyses are performed to estimate the accuracy of the analytical procedure for hybrid FRP-concrete composite compression test, members under eccentrical loading.

• Journal of the Korean institute of surface engineering
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• v.36 no.2
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• pp.135-140
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• 2003

The difference in lattice parameter and thermal expansion coefficient between GaN and Si which results in many defects into the grown GaN is larger than that between GaN and sapphire. In order to obtain high quality GaN films on Si substrate, it is essential to understand growth characteristics of GaN. In this study, GaN layers were grown on Si(111) substrates by MOCVD at three different GaN growth temperatures ($900^{\circ}C$, $1,000^{\circ}C$ and $1,100^{\circ}C$), using AlN and LT-GaN buffer layers. Using TEM, we carried out the comparative investigation of growth characteristics of GaN by characterizing lattice coherency, crystallinity, orientation relationship and defects formed (transition region, stacking fault, dislocation, etc). The localized region with high defect density was formed due to the lattice mismatch between AlN buffer layer and GaN. As the growth temperature of GaN increases, the defect density and surface roughness of GaN are decreased. In the case of GaN grown at $1,100^{\circ}$, growth thickness is decreased, and columns with out-plane misorientation are formed.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.2
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• pp.205-210
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• 1998

$Li^+$ and $Mo^{6+}$ containing huntite borates $YbAl_3(BO_3)_4$were grown by spontaneous crystallization. All crystal show only the huntite-borate phase detected by X-ray powder diffraction analysis. On the basis of the data of the composition analysis, the occupation mechanism of each cation in the huntite structure has been discussed. $Li^+$ and $Mo^{6+}$ containing $YbAl_3(BO_3)_4$shows a six times higher intensity of the green light SHG detected by the powder technique than YAl_3(BO_3)_4$.

• Journal of the Korean Magnetics Society
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• v.23 no.6
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• pp.188-192
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• 2013

The magnetic interaction effect on the magnetic activation volume and area of electrodeposited CoPt magnetic films was investigated. The dipolar interaction was predominant interaction mechanism for all samples. And the interaction strength was increased with decreasing current density and increased with increasing sample thickness. Although the activation volumes of the samples fabricated at low current density were larger than those of the high current density samples, the sample thickness seemed to have little influence on the variation of activation volume. But it was found that the activation area was apparently affected by the magnetic interaction strength as well as the current density.

• Korean Journal of Agricultural Science
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• v.41 no.2
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• pp.113-117
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• 2014

This study was conducted to evaluate the efficacy of benzobicyclon mixtures by using Remote-controlled aerial application (RCAA) to control annual and perennial weeds in rice paddy field. Eight annual weed species including Echinochloa crus-galli L. and three perennial weeds were dominated in the experimental field. Application of benzobicyclon mixtures using RCAA was highly effective to control both annual and perennial weed species. When compared with untreated control, no visual injuries were detected at single and double dosage of benzobicyclon mixtures. Finally, rice yield in the benzobicyclon mixtures was as much as that in the hand weeding. This study indicates that benzobicyclon mixtures using RCAA can be applied to control both annual and perennial weed species in rice paddy field.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.25-28
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• 2008

Generally, reinforced concrete structures exposed to the outside temperature are affected by freezing and thawing process during winter and early spring. These freezing and thawing process can lead to the reduction in durability of concrete as cracking or surface spalling. This paper is to study the hysteretic behavior of RC beams exposed to freezing and thawing under cyclic loadings. To compare the difference in hysteretic behavior of RC Beams, limited tests were conducted under different types of damage and freezing and thawing cycles. For this purpose, six specimens were tested. It is thought that experimental results will be used as basic data to evaluate hysteretic behavior of RC beams exposed to freezing and thawing.

• Journal of the Korean Ceramic Society
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• v.39 no.6
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• pp.570-575
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• 2002

The present tendency of electrical and electronics is concentrated on MEMS devices for advantage of miniaturization, intergration, low electric power and low cost. Therefore it is essential that high aspect ratio and high etch rate by HDP technology development, so that silicon deep trench etching reactions was studied by ICP equipment. Deep trench etching of silicon was investigated as function of platen power, etch step time of etch/passivation cycle time and SF$\_$6/:C$_4$F$\_$8/ flow rate. Their effects on etch profile, scallops, etch rate, uniformity and selectivity were also studied.

• Korean Journal of Child Studies
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• v.34 no.4
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• pp.163-177
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• 2013

Digital technology has advanced rapidly and it is anticipated that multimodal ways of meaning-making will become increasingly important. Consequently, teaching multimodal literacies is becoming a major issue in education. This study focuses on the use of picture diaries as a means of teaching multimodal literacies. Picture diaries are one of the basic and unique multimodal texts used in lower elementary level classes in Korea. A further advantage is that it is a promising text model which can be taught in unplugged ways. In order to explore the educational implications of using such picture diaries, this study sought to analyze the ways in which twenty four $1_{st}$ graders in an elementary school constructed meaning with written language and pictures in composing picture diaries. 251 picture diaries composed during several months of their $1_{st}$ grade period were analyzed based on the constant comparative method. The results indicated that the students utilized both written language and pictures in diverse and creative ways to provide their audience with more comprehensive meaning. These results indicate that teachers need to consider their students as active multimodal meaning-makers and provide their students with more opportunities to practice multimodal meaning-making and share their experiences.