• Economic and Environmental Geology
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• v.56 no.6
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• pp.899-909
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• 2023

In this study, the material scientific characteristics of Hobun pigments used as white inorganic pigment for traditional cultural heritage were identified according to the type of shell and calcination and evaluated the stability of the preservation environment. For the purpose of this, we collected 2 different types of Hobun pigments made by oyster and clam shell and its calcined products(at 1,150℃). Hobun pigments before calcined identified calcium carbonate such as calcite, aragonite but calcination derived changing main composition to portlandite and calcite. Results of FE-SEM showed characteristics microstructure for each shell but pigments after calcined observed porous structure. Porous granule highly caused oil adsorption according to increase specific surface area of pigments. In addition, the whiteness improved after calcined pigments compared to non-calcined pigments, and the color improvement rate of Hobun pigment (CS) which made of clam shell was higher. As a result of the accelerated weathering test, the Hobun pigment-colored specimen had a color difference value of less than 2 after the test, which was difficult to recognize with the naked eye. In particular, the color stability has improved as the color difference value of the Hobun pigment is smaller after calcined compared to before non-calcined pigment. However, it was confirmed that the stability of the painting layer was lower in the specimen after calcined pigment. For antifungal activity test, Aspergillus niger, Tyromyces palustris and Trametes versicolor were used as test fungi, and all pigments were found to have preventive and protective effects against fungi. Especially, the antifungal effect of the calcined pigment was excellent, which is due to the stronger basicity of the pigment.

• Journal of the Korean Geographical Society
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• v.30 no.2
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• pp.103-119
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• 1995

This Paper aims to compare the lower marine terraces distributed from Muckho to Gangneung in the mid-eastern coast of Korean peninsula by the geomorphic method of using characteristies of terrace features and terrace deposits, paleosol, and fossil cryogenic structures, and to estimate the age of the lower marine terraces on the basis of the comparisons of those with the characteristics of thalassostatic terrace in adjacent rivers. The 1ower marine terraces in this area can be classified into two levels, i.e., lower marine terrace I and II surfaces, in desending order, according to the difference of former shoreline altitude. The former shoreline heights of the lowerm marine terrace I and II surfaces are 18m and 10m, respectiveiy. The width of the I surface is broader and distributed more continuousiy than that of II surface. Daejin I surface in Muckho coast, and Myeongju and Anin terrace in Gangneung coast could be classified into the lower marine terrace I surface, and Daejin II surfaCe into II surface. The Surface of ancient shore platform of the lower marine terrace I and II surfaces were weathered, and the color of the terrace deposit ranges from red to reddish brown. And this terrace deposit is covered with slope deposit of Last Glacial or fossil periglacial structures (platy structure and vecicle) of Last Glacial are formed in terrace deposit. These facts indicate that the lower marine terrace I and II surfaces had been formed before the Last Glacial, and then affected by chemical weathering under warm environment, finally followed by cold period. But the deposit of the lower marine terrace I surface is more weathered than that of II surface. And pseudogleyed red soil, which is developed in I but not in II surface, could be judged to have been formed in the Last Interglacial culmination stage (Oxygen isotope stage 5e). Therefore, in terms of the degree of weathering of the terrace deposit and the existence of pseudogleyed red soil, the age of both terrace is thought to be a little different. And the characteristics of the above mentioned II surface are accord with those of thalassostatic terrace formed in middle or late period of the Last Interglacial (5e or 5a). Thus on the basis of above all points, the lower marine terrace I and II surfaces in this area could be seen to have formed in the Last Interglacial culmination stage and middle or late period of the Last Interglacial, respectively. Because the lower mamine terrace I surface is broadry distributed in the eastern coast of Korea nPeninsula, the surface could be used to be a key surface in studying Quaternary marine terraces.

• Journal of dental hygiene science
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• v.12 no.4
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• pp.320-328
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• 2012

The purpose of this study was to evaluate the tooth whitening and properties of an enamel surface after treatments with tooth bleaching agents that contained dicalcium phosphate dihydrate (DCPD) and hydrogen peroxide (HP). Thirty specimens were obtained from fifteen premolar and were randomly divided into three groups (n=10): 1, 3.5% HP + 0 g DCPD; 2, 3.5% HP + 0.1 g DCPD; 3. 3.5% HP + 1 g DCPD. All groups were bleached 8 hours per day for 14 days. With increasing DCPD concentration, the pH values in the agents increased, making it less acidic. However, there was no statistically significant difference (p>.05). As the concentration of DCPD was increased, the concentration of Ca and P was also increased. In all groups, after the tooth whitening, the tooth color was found to have a value of $L^*$ (p<.05). All groups showed significantly decreased enamel microhardness compared to their baseline (p<.05). The percentage microhardness loss (PML) of the group A1 and A2 were significantly lower than that of group A3. The obvious variation of morphology was observed on enamel surfaces in group A1. Following an analysis of the constituents of enamel surface after bleaching, as DCPD content was increased, the amount of Ca and P was increased. In this study, the experimental results suggest that DCPD/HP agent less demineralization changes such as the erosion morphology and hardness loss without compromising whitening efficiency.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.3
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• pp.381-388
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• 2017

This study was performed to evaluate the effects of Liriopis tuber (SLT) extracts on cookie production conditions for reduction of sugar usage through response surface methodology (RSM). The experimental conditions were designed according to the central composite design with 17 experimental points, including three replicates for three independent variables such as the amounts of SLT extracts, butter, and sugar. The experimental data on quality and sensory evaluation of cookies were fitted with various models, and accuracy of the equations was analyzed by ANOVA. Among various responses, spread ratio, sugar content, lightness, redness, hardness, and sensory properties of color, texture, sweetness, appearance, and overall quality showed significant correlations with the contents of three independent variables. From these results, the optimum formulation of cookies for reduced usage of sugar was calculated as SLT extract 6.84 g, butter 47.20 g, and sugar 36.02 g. Optimized cookies showed improved sensory properties but no difference in sweetness compared to control cookies.

• Food Science and Preservation
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• v.24 no.1
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• pp.74-83
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• 2017

This study was conducted to obtain the optimal conditions of hot air drying for Cudrania tricuspidata by response surface methodology (RSM). The independent variables were blanching time (60, 120, 240 sec), drying temperature (40, 60, $80^{\circ}C$) and drying time (12, 24, 36 h). The dependant variables were total polyphenol content (TPC), total flavonoid content (TFC), DPPH radical scavenging activity (DPPH), and color difference (${\Delta}E$). Viable cell colony was counted according to changes of blanching time. It was confirmed that microorganisms gradually decreased with increasing blanching time. From RSM results, the predicted values of TPC, TFC, DPPH, and ${\Delta}E$ were 8.62 mg GAE/g, 56.65 mg RE/g, 40.26% and 11.69, respectively. Experimental values within the optimal range (240 sec, blanching time; $60^{\circ}C$, drying temperature; 24 h, drying time) were 10.06 mg GAE/g, 49 mg RE/g, 44.99% and 10.53, respectively. The predicted values were similar to the experimental values. Comparing drying tendency according to changes of blanching time, moisture reduction was bigger in the blanched sample than that in control at $40^{\circ}C$. However, the differences between blanched and control decreased with increase of drying temperature. Viable cell gradually decreased as increasing blanching time.

• Korean Journal of Heritage: History & Science
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• v.56 no.4
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• pp.160-189
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• 2023

The Cheonjeon-ri petroglyph is inscribed with shale formation belonging to the Daegu Formation of the Gyeongsang Supergroup in the Cretaceous of the Mesozoic Era. This rock undergoes thermal alteration to become hornfels, and has a high hardness and dense texture. Rock-forming minerals have almost the same composition as quartz, alkali felspar, plagioclase, calcite, mica, chlorite and opaque minerals, but calcite is rarely detected in the weathered zone. The petroglyph forms a weathered zone with a certain depth, and there is a difference in mineral and chemical composition between weathered and unweathered zones, respectively. The CaO contents of the weathered zone were reduced by more than 90% compared to that of the unweathered zone, because calcite reacted with water and dissolved. As a result of calculating the surface weathering depth for the petroglyph with the transmission characteristics of X-rays, depth of the parts in falling off and exfoliation showed a depth of about 0.5 to 1 mm, but the weathering depth in most areas was calculated to be about 3 to 4 mm. This can be proved by the contents and changes of Ca and Sr. The surface discolorations of the petroglyph are distributed with different color density, and the yellowish brown discoloration is alternated with a thin biofilm layer, showing a coverage of 79.6%. Therefore, periodic preservation managements and preventive conservation monitoring that can effectively control the physicochemical and biological damages of the Cheonjeonri petroglyph will be necessary.

• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.126-133
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• 2019

In recent years, the deterioration of fruit quality caused by poor coloration and sunburn disorder has become serious problems in apple market, which is a result of the increase of surface temperature due to the abnormal temperature increase during summer season. This study was conducted to investigate the effect of wind net shading and fine water spray using sprinkler on fruit coloration, sunburn damage and overall fruit quality of 'Fuji' and 'Hongro' apples. Fifteen sprinklers (7L/hr) were installed at the orchard of the Chungcheongnam-do Agricultural Research and Extension Services, located in Sinam-myeon Chungcheongnam-do Korea, at a height of 3m above the apple tree of $1.5m{\times}3.5m$ north-south direction. Fine water spraying treatment was divided into day time spray (10:00 am to 6:00 pm) and all day spray (10:00 am to 10:00 pm) from early July to 10 days before harvest in 2017 and 2018 season, respectively. Temperature of the surface of apple fruit, characteristic of fruit, and degree of sunburn damage were investigated. In 'Fuji', the fruit surface temperature checked at 2 pm on August 10 was decreased considerably in the day time spray ($35.6^{\circ}C$) and wind net ($39.0^{\circ}C$) when compared with the untreated control ($44.4^{\circ}C$). Similarly, the fruit surface temperature also decreased considerably in the all day spray ($35.1^{\circ}C$) and wind net ($36.9^{\circ}C$) treatments when compared with the untreated control ($46.5^{\circ}C$) in 'Hongro' apples. The incidence of sunburn disorder was significantly decreased with day time spray (5.0%), all day spray (5.8%) and wind net (7.0%) when compared with untreated control (23.4%) in 'Fuji' apples. As a results, the treatment of fine water spray and wind net consequently showed 26% and 34% increase of redness ($a^*$) value in the skin color difference, respectively, in 'Fuji' apples.

• Journal of Conservation Science
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• v.25 no.3
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• pp.283-291
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• 2009

Methyl Bromide that was used as fumigation gas turned out to be the substance of destroying the ozone layer. For that reason, at the Montreal Protocol in 1987 the use of methyl bromide was forbidden starting 2005 in the advanced country. Also according to the 2007 Bali Protocolly methyl bromide is expected to be forbidden and therefore the purpose of this study is to find out the effects of substitution fumigation gas (Ethylene Oxide+HFC 134a, Methyl Iodide, Cyanogen and Argon) on the metal(silver, copper and iron), wood(oregon pine), pigment(yellow, red, blue, white and black), textile(hemp, ramie, jute, silk1 and silk2 / indigo, safflower and cork) and paper. After the fumigation test, ethylene oxide+HFC 134a did not have changes in the weight and color of the material itself before and after the experiment. On exterior alteration, color change occurred partly on paper and metal. Also, in most materials color change extent was 0.5 to 1.5 on the average and showed scanty difference. The materials after the fumigation test with methyl iodide did not show weight changes after the test. However, color changes more than 1.0 was shown in most of the materials especially in dyed textile material. In blue pigment, the discoloration on the surface could be seen by naked eyes. Fumigation test with cyanogen gas did not show weight changes and discoloration is more than 1.5 before and after the test. The weight changes of test materials with the argon gas was decreased about 3 to 6%. It can be observed that discoloration on paper was generated. Color changes can be seen on jute dyed with safflower and cork for two weeks with argon gas and the extent was 6.3 and 6.0.

• Polymer(Korea)
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• v.34 no.6
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• pp.574-578
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• 2010

In this study, the caprolactone modified hydroxy acrylates (CHAs) were synthesized by ring-opening reaction of caprolactone and 2-hydroxyethyl acrylate (2-HEA) as initiator. Also, the caprolactone modified urethane acrylate (UA) oligomers were synthesized by condensation reaction of previously synthesized CHAs, 2-hydroxyethyl acrylate (2-HEA) and hexamethylene diisocyanate trimer (HDT). Using the hydroxy number of CHAs, the molecular weights of the CHAs were calculated easily and their molecular weight was similar to the theoretical molecular weight of them. The viscosity of UA oligomers decreased as increasing a content of CHA in the UA oligomer. Cure films were prepared from UA oligomer, reactive diluents, and UV initiator to investigate their physical properties. The thermal stability and color difference on high temperature for the cured film were improved as increasing the crosslinking density. Their surface hardness was also increased as increasing crosslinking density of the cured films, but their elongation at break was decreased.

• Korean Journal of Food Science and Technology
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• v.36 no.1
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• pp.69-74
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• 2004

'Mixing' and 'immersion' $CaCl_{2}$ treatment methods were tested for preparation of bio-degradable films using powders of sea mustard (Undaria pinnatifida) (leaf, stem, and sphorophyll), sweet tanlge (Laminaria japonica), and fusiforme (Hizikia fusiforme) by extracting alginate through acid-alkali extraction method. Except fusiforme powder, flexible, free-standing films were produced by both methods using all marine algae powders tested. Except water solubility (WS), surface color, tensile strength (TS), elongation at break (E), and water vapor permeability (WVP) did not show distinct difference between $CaCl_{2}$, treatment methods. Although TS, WVP, and WS of marine algae powder films were lower than those of alginate films, they indicate potential in application as a new source of bio-degradable packaging materials.