• Journal of Conservation Science
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• v.31 no.4
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• pp.331-339
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• 2015

This study were conducted the particle-size analysis on 57 blue pigments to understand the step distribution characteristics of blue pigments made out of Azurite by using Malvern's Mastersizer 2000. As the result, most of the conventional blue pigments in Korea, Japan, and Chinese showed good granularity step separation except for few, and the smaller the particle, the more the Span value increased and the wider the granularity distribution range. On the basis of Friedman and Sanders's Grain size, most of the pigments were sand size to silt size. 72.2% of B-100 was clay size and 2.5% of A-14 was gravel size. Even the same components can differ by the grain size directly affecting the important property such as color formation, oil absorption, specific gravity, usability, etc. so the information about the granularity distribution would be used for basic data to deal with natural pigments.

• Resources Recycling
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• v.27 no.5
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• pp.61-68
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• 2018

The aluminum dross is oxide generated on the surface of the molten metal during the aluminum melting process and it is divided into white dross and black dross according to presence of the Salt flux. White dross has high metal content and is recycled via the melting process. Black dross is largely berried, because the it has a low metal content and difficulty in separating the components. Black dross contains a salt components such as NaCl and KCl, and inorganic materials such as $Al_2O_3$ and MgO, and it is necessary to study the technology to recover and recycle such valuable resources. In this study, a process for recycling aluminum black dross was proposed. The inorganic and soluble substances present in the black dross were separated through crushing-dissolution-solid/liquid separation-decompression evaporating. By controlling the ratio of water and black dross, the recovery condition of the separated product was optimized and we confirmed the highest Salt flux recovery efficiency 91 wt.% at black dross:water ratio 1:9. Finally, Through the synthesis of zeolite using recovered ceramic material, the materialization possibility of black dross was confirmed.

• Membrane Journal
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• v.25 no.1
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• pp.75-83
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• 2015

In this study, chlorophylls were been extracted from common local plants, deposited on polypropylene (PP) substrate using various approaches, and the oxygen generation effect of the chlorophylls were investigated. The loading of chlorophylls on the substrates was achieved by dipping and spraying methods, where the spraying coating showed overall better results regarding oxygen generation from the combustion experiments in the closed vessel or in the isolated vacuum oven cell than those of dip coating. In addition, a composite substrate was prepared by nylon6/6 nanofiber on the PP substrate, and it exhibited an increase in the activation of chlorophylls. In the case of samples containing titanium dioxide ($TiO_2$), the reaching time of oxygen concentration from 16% to 21% and the combustion test using a candle for a sample with 50% chlorophylls showed similar results to those of a sample without $TiO_2$. As such, combining a spray coating and $TiO_2$ incorporation into gas separation membrane systems are expected to be useful to understand the fundamentals of material properties for their applications as oxygen generation membranes and air filtration systems.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.3
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• pp.253-268
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• 2012

Full-mouth reconstruction of a patient using dental implants is a challenge if there is vertical and horizontal bone resorption, since this includes the gingival area and restricts the position of the implants. however, hard- and soft-tissue grafting may allow the implants to be placed into the desired position. Although it is possible to regenerate lost tissues, an alternative is to use fixed detachable prostheses that restore the function and the esthetics of the gingiva and teeth. Various material combinations including metal/acrylic, metal/ceramic, and zirconia/ceramic have been used for constructing this type of restoration. Other problems include wear, separation or fracture of the resin teeth from the metal/acrylic prosthesis, chipping or fracture of porcelain from the metal/ceramic or zirconia/ceramic prosthesis, and fracture of the framework in some free-end prostheses. With virtually unbreakable, chip-proof, life-like nature, monolithic zirconia frameworks can prospectively replace other framework materials. This clinical report describes the restoration of a patient with complete fixed detachable maxillary and mandibular prostheses made of monolithic zirconia with dental implants. The occluding surfaces were made of monolithic zirconia, to decrease the risk of chipping or fracture. The prostheses were esthetically pleasing, and no clinical complications have been reported after two years.

• Korean Journal of Construction Engineering and Management
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• v.12 no.1
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• pp.3-12
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• 2011

Technology based civilization has made a sustained advancement, resulting in economic growth and material prosperity. The outcome was the beginning of environmental destruction. Especially, in regard to construction, it has been recognized as a key culprit for pollution. As such, the construction industry has recently shown interest in the environment, as it has been applying environment friendly method of construction and reducing wastes. As the number of old common housing increases in our country, reconstruction and remodeling are implemented as a means of improvement. However, it can be said that remodeling is the inevitable option because of cost and environmental problems associated with reconstruction. As part of its feature, remodeling work is preceded by removal work. And, removal work inevitably creates construction wastes. Treatment of wastes that takes into consideration environmental aspects is important and for this, removal work that is based on environment friendly remodeling to ensure selective separation must be implemented. Yet, a removal work based on environment friendly remodeling has a lower level of output compared to existing methods. Because remodeling work by its nature has a post construction work which proceeds after it, securing work efficiency is important as the removal work is a critical path activity. Thus, the present study improves the work process of a removal work that is based on environment friendly remodeling so that it becomes a work process that includes work efficiency. For this, as a case study, old common housing has been selected, and a TACT process has been developed which is based on data acquired from environment friendly removal work. And, this study develops an optimal TACT process which is based on environment friendly remodeling by conducting a simulation for a 15 floor apartment.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.3
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• pp.285-291
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• 2015

Purpose: The hydrogel lenses have been functionalized with HA(Hyaluronic Acid) using two different methods: construction of an IPN(Interpenetrating Polymer Networks) and formation of CCB(Chemical Covalent Bonding). The lysozyme adsorption and physical properties such as optical transmittance and water content of the hydrogel lenses have been investigated in order to determine whether method is suitable for the application potentials in contact lens industry. Methods: HA have been added to the hydrogel lenses prepared in the Lab using the two different method, e.g. IPN and CCB. The optical transmittance was measured in the wavelength range of 300~800 nm. The water content was measured by the gravimetric method using 0.9% NaCl saline solution. The amounts of adsorbed lysozyme on the contact lenses was analyzed by HPLC after incubation for 12h in artificial tears. Results: The water content of the HA added hydrogel contact lenses was increased, and the lens made by IPN method showed higher water content than the lens made by CCB method. The optical transmittance was over 90% both before and after addition of HA. Comparing the lysozyme adsorption reduction ratio, contact lens manufactured by IPN method was 60.0%, and the lens made by CCB method was 40.4%. Conclusions: CCB method is appropriate to distribute the functional material evenly throughout the lens, whereas IPN method is effective for the case of giving the functionality on the lens surface without phase separation.

• Clinical and Experimental Reproductive Medicine
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• v.26 no.2
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• pp.257-263
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• 1999

It is well known that discard of seminal plasma from the semen and separation of motile sperm should be preceded before insemination for IUI or IVF. Till now, more than ten kinds of semen treatment methods have been developed. Of those, swim-up and Percoll methods have been used widely in ART laboratories as a routine semen treatment methods because of its advantages. However, there are reports that Percoll can make a genetic trouble because of its chemical structure and therefore the necessity has been arisen to substitute Percoll for other equivalent materials. This study was performed to evaluate the effects of three different sperm preparation methods (swim-up, Percoll and Sil-Select) on sperm motility, sperm recovery rate and fertilization rate. Also, the feasibility of using Sil-Select instead of Percoll in ART was evaluated. Each semen samples were divided into three fractions and motile sperm were recovered by swim-up, Percoll and Sil-Select gradient centrifugation methods. Normal and sub-normal criteria of fifteen semen samples and seventeen IVF cycles were included in these study. As results, no significant difference was found in sperm recovery rate in normal semen treated by a Swim-up, Percoll and Sil-Select method ($13.2{\times}10^6,\;17.5{\times}10^6\;and\;17.7{\times}10^6$ respectively). The initial sperm motility was 61.9% and this increased to 87.1%, 92.6% and 89.5% through Swim-up, Percoll and Sil-Select treatment, respectively. Higher motility was observed in Percoll and Sil-Select treated groups (81.5%, 79.2%, respectively) than swim-up group (66.8%) after incubation for 24hrs. In sub-normal group, sperm recovery rates were higher in Sil-Select group $(2.9{\times}10^6)$ than Percoll gradients group $(1.8{\times}10^6)$. In IVF cycles, the outcomes of fertilization using sperm treated by swim-up and Sil-Select group were similar (82.2%, 79.7% respectively). In conclusion, our results indicate that Sil-Select can be used as a substitute material for sperm preparation instead of Percoll.

• The Journal of the Petrological Society of Korea
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• v.14 no.3 s.41
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• pp.157-168
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• 2005

Trachytic rocks among the bimodal metavolcanic rocks of the Gyemyeongsan Formation and adjacent areas are investigated. Some rocks reveal very high content of iron and most rocks show very high abundances of rare earth elements and high field strength elements. Most rocks show significant Eu negative anomaly, which can be interpreted as the result of plagioclase fractionation. Lack of noticeable Nb negative anomaly indicates not-involvement of crustal material in their generation, which excludes the arc environment or remelting of continental crust from their genetic process. Metatrachytes of the Gymyeongsan Formation are plotted within the within-plate environment of the tectonic discrimination diagram utilizing immobile high field strength element Nb and Y. They also show typical characteristics of A-type magma, such as high Ga content. Considering their affinity to Al-type of Eby (1992) and their age of 750 Ma (Lee et al., 1998), they seem to have been produced by the differentiation of mantle-derived within-plate magmatism at the rift, related with the separation of Neoproterozoic supercontinent Rodinia. Possible connection of Gyemyeongsan and Munjuri Formations of the Okcheon metamorphic belt, at least part of them, to the Cathaysia block of South China during the Neoproterozoic is strongly suggested.

• Food Science of Animal Resources
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• v.37 no.6
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• pp.940-947
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• 2017

Goat milk has a protein composition similar to that of breast milk and contains abundant nutrients, but its use in functional foods is rather limited in comparison to milk from other sources. The aim of this study was to prepare a goat A2 ${\beta}$-casein fraction with improved digestibility and hypoallergenic properties. We investigated the optimal conditions for the separation of A2 ${\beta}$-casein fraction from goat milk by pH adjustment to pH 4.4 and treating the casein suspension with calcium chloride (0.05 M for 1 h at $25^{\circ}C$). Selective reduction of ${\beta}$- lactoglobulin and ${\alpha}_s$-casein was confirmed using sodium dodecyl sulphate-polyacrylamide gel electrophoresis and reverse-phase high-performance liquid chromatography. The hypoallergenic property of A2 ${\beta}$-casein fraction was examined by measuring the release of histamine and tumor necrosis factor alpha from HMC-1 human mast cells exposed to different proteins, including A2 ${\beta}$-casein fraction. There was no significant difference in levels of both indicators between A2 ${\beta}$-casein treatment and the control (no protein treatment). The A2 ${\beta}$-casein fraction is abundant in essential amino acids, especially, branched-chain amino acids (leucine, valine, and isoleucine). The physicochemical properties of A2 ${\beta}$-casein fraction, including protein solubility and viscosity, are similar to those of bovine whole casein which is widely used as a protein source in various foods. Therefore, the goat A2 ${\beta}$-casein fraction may be useful as a food material with good digestibility and hypoallergenic properties for infants, the elderly, and people with metabolic disorders.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.11
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• pp.764-770
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• 2014

This study assessed analysis of N-nitrosamines by separation, identification, and quantification using a gas chromatography (GC) mass spectrometer (MS) with electron impact (EI) mode. Samples were pretreated by a automated solid phase extraction (SPE) and a nitrogen concentration technique to detect low concentration ranges. The analysis results by EI-GC/MS (SIM) and EI-GC/MS/MS (MRM) on standard samples with no pretreatment exhibited similar results. On the other hand, the analysis of pretreated samples at low concentrations (i.e. ng/L levels) were not reliable with a EI-GC/MS due to the interferences from impurity peaks. The method detection limits of eight (8) N-nitrosamines by EI-GC/MS/MS analysis ranged from 0.76 to 2.09 ng/L, and the limits of quantification ranged from 2.41 to 6.65 ng/L. The precision and accuracy of the method were evaluated using spiked samples at concentrations of 10, 20 and 100 ng/L. The precision were 1.2~13.6%, and the accuracy were 80.4~121.8%. The $R^2$ of the calibration curves were greater than 0.999. The recovery rates for various environmental samples were evaluated with a surrogate material (NDPA-$d_{14}$) and ranged 86.2~122.3%. Thus, this method can be used to determine low (ng/L) levels of N-nitrosamines in water samples.