• Korean Journal of Environmental Agriculture
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• v.9 no.1
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• pp.39-45
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• 1990

We established HPLC method for MAs (mugineic acid and its analogous phytosiderophore) determination. It was found that major phytosiderophores existed in high heavy metal-induced rice roots were MA (mugineic acid) and DMA (2'-deoxymugineic acid). The two MAs (MA and DMA) were simultaneously secreted at maximum rate at 12 : 00-14 : 00. On the other hand, the secretion of amino acids gradually decreased from after sunrise (7 : 00) to sunset (21 : 00). Fluctuaton in daily MAs secretion had rhythmic variation which occurred at intervals of about 4 days. The stimulation of MAs secretion from the roots was attributed not only to the light/dark cycle but to the increase in temperature. Temperature variation played a more important role than a photoperiod in MAs secretion from the roots. The initiation time of MAs secretion was positively correlated with rising time in temperature($20-30^{\circ}$) during the dark period.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.184-189
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• 2018

Recently, research on lightweight automobiles is increasing continuously to respond to the high safety standards and environmental regulations. The application of high strength steel is one of the effective methods for developing lightweight car bodies. A TWB (Tailor Welded Blank) is major method that allows partial high strength with light weighting using a multi-thickness and multi-material welded blank. On the other hand, additional welding process is required to prepare the blank and quality control for the welding process also required. To secure this point, the TRB (Tailor Rolled Blank) method was suggested. In the TRB method, the thickness of sheet is controlled by the rolling presses and the production efficiency is much higher than welding in TWB methods. In this study, the formability of high strength TRB steel plate was analyzed to examine the rolling effect of the blank. The formability of the specimen was tested using 0.8 and 1 mm thick steel sheets for the TRB plate. The strain was analyzed by the digital image sensing of grid markings on the specimen and the forming limit diagram was calculated. An Erichsen test for the 0.8 and 1 mm thick TRB specimens was carried out and the formability was investigated by comparing with FE analysis.

• Journal of Technologic Dentistry
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• v.29 no.1
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• pp.121-131
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• 2007

A preparation process's conditions of aqueous sol which contains anatase-type nano titania particles with photocatalyic properties was established by using Yoldas process, so called, DCS(Destabilization of Colloidal Solution) process in this study. And crystal size change and phase transformation of titania particles in aqueous titania sol depending on reaction conditions was investigated by a light scattering method and XRD analysis of frozen dried powders, respectively. This sol with photo catalytic nano titania particles was used to the following hydrophilic hybrid coating film's fabrication and its properties was evaluated. Subsequently, for coating film using the above mentioned aqueous titania sol, non-aqueous titania sol was prepared without any chemical additives and its time stability according to aging time was investigate. By using the above mentioned aqueous titania sol and non-aqueous sol, a complex oxide coating sol for metal and ceramic substrate and a organic-inorganic hybrid coating sol for polymer substrate was prepared and it's hydrophilicity depending on UV irradiation conditions was evaluated. As a conclusions, the following results were obtained. (1)Aqueous titania sol The average particle size of titania in formed aqueous titania sol was distributed between 20$\sim$90nm range depending on reaction conditions. And the crystal phase of titania powders obtained by frozen drying method was changed from amorphous state to anatase and subsequently transformed to rutile crystal phase and it is attributed to concentration gradient in aqueous sol. (2)Non-aqueous titania sol Non-aqueous titania sol was prepared using methanol as a solvent and a little distilled water for hydrolysis and nitric acid as a catalyst were used. The obtained non-aqueous titania sol was stable at room temperature for 20 days. Additionally, non-aqueous titania sol with addition of chealating reagent such as acethylaceton and ethylene glycol prolonged the stability of sol by six months. (3)Complex sol and hybrid sol with super hydrophilicity The above mentioned aqueous titania sol as a main photocataylic component and non-aqueous titania sol as a binder for coating process was used to prepare a complex sol used for metal, ceramic and wood material substrate and also to prepare the organic-inorganic hybrid sol for polymer substrate such as polycarbonate and polyethylene, in which process APMS(3-Aminopropyltrimethoxysilane), GPTS(3-Glycidoxypropyl-trimethoxysilane) as a hydrophilic silane compound and HEMA(2-Hydroxyethyl methacrylate) as a forming network in hybrid coating film were used. The hybrid coating film such as prepared through this process showed a superhydrophilicity below 1$10^{\circ}$ depending on processing conditions and a pencil's hardness over 6 H.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.61-66
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• 2010

The purpose of this experiment is to analyze the basic status of brain. Which are consist of rest, attention and concentration, of the brain by measuring the temperature of color by changing RGB color after manufacturing LED-illumination stand. Basic status (rest, attention and concentration) of experimenter were measured temperature of colors having three difference temperature like as $2,300^{\circ}K$, $4,000^{\circ}K$ and $6,000^{\circ}K$. The results was shown that experimenter feels more comfortable and relaxation by decreasing the temperature of color. For example we can see the little increase of concentration index at $4,000^{\circ}K$ condition and we can estimate that right brain can be more activated at the $4,000^{\circ}K$ condition. But we can not find out any different at the $6,000^{\circ}K$ condition. Main cause of no difference from the color temperature was the similarity of color temperature under the general fluorescent lamp. And interface temperature of radiant heat design results LED and PCB was approximately 80 degrees to COMSOL Multiphysics, and changed until approximately 50 degrees until a floor plane of PCB, and verification as arranged chip LED to metal PCB, and it was possible, and a near radiant heat design was confirmed to an approximate value of, as a result, acid manufacture.

• Applied Biological Chemistry
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• v.42 no.2
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• pp.134-139
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• 1999

The characteristics of anthocyanin pigments extracted from cherry(Prunus serrulata L. var. spontanea Max. Wils.) were investigated at the various conditions, such as light, temperature, organic acid, metal ion and pH. The pigments were fairly stable under the sunlight during the 20 days storage period at room temperature. The pigments covered with the Al-foil, as well as red, blue, green and yellow films, were very stable at pH 2.5. The high thermal stability (over the 64% at $115^{\circ}C$, 30 min) of the pigments in the dark at pH 2.5 was also found. In the presence of organic acid, the hyperchromic effect of red color was greatly increased in the dark at $25^{\circ}C$. Addition of metal ion, such as $Na^+,\;K^+,\;Mg^{2+},\;Ca^{2+}\;and\;Mn^{2+}$, was contributed on the stability in color at pH 2.5 throughout 20 days storage period in the dark at $25^{\circ}C$. However, $Cu^{2+}\;and\;Fe^{3+}$ caused the rapidly degradation of pigments, and $Al^{3+}$ converted red color to blueish violet. The hyperchromic effect of the red color increased, as pH decreased. Therefore, these results indicated that cherry anthocyanin pigments might be used as the potential sources of natural red colorant for foods.

• Korean Journal of Materials Research
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• v.16 no.4
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• pp.225-230
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• 2006

Nanoimprint lithography (NIL) is a novel method of fabricating nanometer scale patterns. It is a simple process with low cost, high throughput and resolution. NIL creates patterns by mechanical deformation of an imprint resist and physical contact process. The imprint resist is typically a monomer or polymer formulation that is cured by heat or UV light during the imprinting process. Stiction between the resist and the stamp is resulted from this physical contact process. Stiction issue is more important in the stamps including narrow pattern size and wide area. Therefore, the antistiction layer coating is very effective to prevent this problem and ensure successful NIL. In this paper, an antistiction layer was deposited and characterized by PECVD (plasma enhanced chemical vapor deposition) method for metal stamps. Deposition rates of an antistiction layer on Si and Ni substrates were in proportion to deposited time and 3.4 nm/min and 2.5 nm/min, respectively. A 50 nm thick antistiction layer showed 90% relative transmittance at 365 nm wavelength. Contact angle result showed good hydrophobicity over 105 degree. $CF_2$ and $CF_3$ peaks were founded in ATR-FTIR analysis. The thicknesses and the contact angle of a 50 nm thick antistiction film were slightly changed during chemical resistance test using acetone and sulfuric acid. To evaluate the deposited antistiction layer, a 50 nm thick film was coated on a stainless steel stamp made by wet etching process. A PMMA substrate was successfully imprinting without pattern degradations by the stainless steel stamp with an antistiction layer. The test result shows that antistiction layer coating is very effective for NIL.

• Applied Chemistry for Engineering
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• v.9 no.4
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• pp.497-503
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• 1998

The catalytic oxidation of 1.2-dichloroethane was investigated over precious metal supported on alumina using a fixed bed microreactor. Among the catalysts tested, the conversion of 1.2-dichloroethane decreased in the following order : Ru > Pt > Pd $${\sim_=}$$ Rh and Pt was found to be the most active catalyst for the complete oxidation of 1.2-dichloroethane to $CO_2$. Major products containing carbon were vinyl chloride and $Co_2$ at temperature ranging from 200 to $400^{\circ}C$. The presence of vinyl chloride in products suggests that the first step in the oxidation of 1.2-dichloroethane is dehydrochlorination and the second is oxidation of vinyl chloride to $CO_2$. To investigate the effect of HCl on the activity of the complete oxidation, some experiments were conducted by adding HCl to the feed. The presence of HCl increased the conversion of 1.2-dichloroethane below $300^{\circ}C$ owing to the increase of surface acidity, but it didn't affect the conversion above $300^{\circ}C$. The reversible adsorption of HCl onto catalyst surface inhibited the complete oxidation to $CO_2$.

• 보존과학연구
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• s.33
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• pp.125-148
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• 2012

The Octagonal nine storied pagoda of Woljeongsa Temple consists mainly of granite with the rockforming minerals quartz, plagioclase, microcline, and biotite. The surface of the stone stupa is light brown that has been discolored by the rust from the metal ornament and aids. The surface of the stylobate and roof stone is colonized by biological contaminants. Therefore, a comprehensive deterioration diagnosis was carried out in this study, and conservation treatment was conducted. It was proven that the $Fe^{2+}$ yield increases depending on the count of poultice used with oxalic acid, but the $Mg^{2+}$, $Al^{3+}$, and $Ca^{2+}$ yields were marginal following the preliminary test. Therefore, the use of poultice is an effective way of removing the rust, and only marginally influences the rock. The biological contaminants were removed through dry cleaning, and the soil located under the contaminants was removed through wet cleaning. Based on this, the dry and wet cleaning of all the biological contaminants, and the use of poultice with oxalic acid, were done to remove the rust. For the conservation treatment of the metal ornament, the rust was removed through physical cleaning, and anticorrosion treatment was performed on the iron ornament using Renaissance wax and copper ornament by BTA.

• Journal of Life Science
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• v.19 no.8
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• pp.1132-1138
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• 2009

We investigated the physicochemical stabilities and biological activities of ethanol- extracted pigment from marine bacterium Pseudoalteromonas psicida TA20. This bacterial pigment was very stable at a pH range of between 4.0 and 8.0 at a temperature below $40^{\circ}C$. In the presence of light, the pigment was also very stable, showing more than 90 percent remaining absorbance during 14 days at $25^{\circ}C$. The stability of the pigment, when metal ions were present, showed higher stability in all examined metal ions except for $Al^{3+}$ and $Cu^{2+}$, especially in the presence of $Fe^{2+}$. This pigment showed higher stability than other pigment extracts reported. The pigment has free-radical scavenging (3,495 ${\mu}g/ml$) activity and 44% antioxidant protective effect against DNA damage of human lymphocyte cells at a concentration of 10 ${\mu}g/ml$. The results indicate that the bacterial pigment produced a significant reduction in oxidative DNA damage. The pigment also showed antimicrobial activity against major food poisoning bacteria. Therefore, these results suggest that this bacterial pigment could be used as a natural colorant in the food industry, having the advantages of antioxidant and antimicrobial activities.

• Journal of Digital Convergence
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• v.11 no.9
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• pp.325-331
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• 2013

The Baekje Gilt-bronze Incense Burner which was excavated in an ancient temple site in Neungsan-ri, within the City wall of Buyeo-Gun on 23rd December 1993, was a quintessence of the Bakje Arts that people could not have imagined until that time. The Baekje Gilt-bronze Incense Burner transcended 1400 years of time and space. The censer that finally came up to us delivered a kind of a powerful message to us. The power was so strong and mysterious that as if an ancestor who had been sleeping in the grave with a great silent had woken up and become alive to tell us something very precious. Baekje Gilt-bronze Incense Burner, unlike any other existing artifacts, might have a possibility that could provide an insight of the ancients' psych who once lived on our land. This kind of view from several archaeologists, therefore, made our hearts be filled with excitement and flutter. We call 21st century as an era of culture. This era requests that the culture needs to be ethnical but the culture also needs to go beyond that ethnic. In other words, a culture without an ethnic cannot exist, and a culture that puts an ethnic the very first before any other things cannot exist as well. Regaining our identities first and then embracing and harmonizing various cultures can be an wise way overcoming above problem. Hence, through this study, I intend to recognize characteristic of plasticity for Baekje Gilt-bronze Incense Burner, understand the world of Baekje people's spirit and thus provide an opportunity to shed new light on the Baekje Arts. By doing so, I would like to publicize a metal craft of Korea to the world. I also try to seek for an identity of Korea's craft culture which is receding and find a direction for the Korea's craft.