• Textile Coloration and Finishing
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• v.14 no.1
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• pp.1-10
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• 2002

The aim of study was to elucidate dyeability and antimicrobial and antifungal activity of silk fabrics dyed with Sophora Radix extracts according to different mordants. Dyes were extracted from Sophora Radix using ethanol. Then, silk fabrics were dyed with extracts two times by post-mordanting method in which the extract was 60%(owf), the mordant was 3%(owf), L.R was 1:20, the temperature was $60~60^\circ{C}$, the time of dyeing was 60min., and the time of mordanting was 60min. The dyeability was evaluated by surface color, K/S values and durability of dye. The skin microorganisms used in this study was S. sureus, B. subtilis, S. epidermidis, P. acnes, P. aeruginosa, E coli, A. niger, C. albicans and T. mentatrophytes. The results are as follows; 1. When mordants were added, K/S value of silk dyed was not improved much and surface color was 2.2Y to 8.8Y in H(hue) value which indicated greenish yellow to raddish yellow 2. The color fastness tests to light, perspiration, dry-cleaning, rubbing, and stain fabric washing show 4~5th degree which were valuated excellent. The color fastness to fade washing was improved to 3~4th degree by addition of $K_2CrO_7$ mordants. 3. Antibacterial activity of silk dyed using no-mordant as well as mordants was excellent on S. aureus, B. subtilis, S.epidermidis and P.acnes, but showed poor antibacterial activities on P.aeruginosa and E.coli such as gram negative baterials 4. Antifungal activity of silk dyed with ethanol extracts was good on A.niger, C.candida and T.mentagrophytes. Especially, on T. mentagrophytes there was no growth of fungus during 72 gous in silk dyed mordanting with $SnCl_2\cdot{2H}_2O$.

• Textile Coloration and Finishing
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• v.30 no.4
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• pp.245-255
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• 2018

In this study, cotton fabrics were coated with $TiO_2$ nanoparticles using 3-mercaptopropyltrimethoxysilane(3-MPTMS), which is highly reactive to cotton fabrics, as a medium, and the characteristics, antimicrobial properties, and photodegradation properties of the fibers were measured. The manufacturing process is as follows. (1) 3-MPTMS was added to isopropanol, and $TiO_2$ colloid was added to the mixture to prepare a solution. (2) Cellulose fibers were immersed in the prepared $3-MPTMS/TiO_2$ solution, stirred for 90 minutes at $45^{\circ}C$ in a constant temperature water bath, and dried thereafter. In order to identify the morphology of the cellulose fibers coated with $TiO_2$ nanoparticles, the surface was observed with a scanning electron microscope(SEM), and SEM-EDS was measured to identify the adhesion of $TiO_2$ nanoparticles. The SEM images showed $TiO_2$ nanoparticle and 3-MPTMS coated layers on the fibers and it was identified that $TiO_2$ nanoparticles were attached to the cellulose fibers. The antimicrobial activity of $3-MPTMS/TiO_2$-treated cotton fabrics was measured using a bacterial reduction method. $3-MPTMS/TiO_2$ cellulose fibers which was irradiated by ultra violet light, showed antimicrobial activity against Escherichia coli(ATCC 43895) and Staphylococcus aureus(ATCCBAA-1707) unlike unirradiated fibers. The cellulose fibers were stained with methylene blue and the photodegradation performance of the stained fabrics was analyzed. The stained fabrics showed high degradation performance with photolytic reactions of $TiO_2$ nanoparticles.

• The korean journal of orthodontics
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• v.29 no.4 s.75
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• pp.483-490
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• 1999

Interdental enamel stripping is an usual method for correction of abnormal tooth shape and tooth size discrepancy which is one of the etiologic factors of malocclusion. Clinically it Is useful to correct the minor crowding in anterior teeth and posterior occlusion during finishing stage of orthodontic treatment. But this procedure has risks such as irreversible tooth reduction and remaining roughness of enamel surface can accumulate plaque which can evoke periodontal problem. Even if various methods were introduced to minimize the enamel surface roughness, their evaluation was limited in morphologic differences by scanning electronic microscope(SEM). The purpose of this study was to compare the various interdental enamel stripping method by SEM and to quantify the difference of surface roughness by use of Surfcorder SEF-30D(Kosaka Lab. Ltd.) which can measure the roughness of surface. The stripping methods were divided into mechanical and mechanical-chemical method. Air-rotor stripping and separating strip were used for mechanical stripping and $37\%$ phosphoric acid was used for chemical stripping. The enamel surface roughness after mechanical or mechanical-chemical stripping of interproximal surfaces of premolars which were extracted for orthodontic purpose were measured and compared by means of SEM and $Surfcorder^{\circledR}$, the results were as follows. 1. Enamel surface of primary treated by coarse diamond bur and separating strip groups showed highest value of roughness. 2. To compare the primary treated groups between mechanical and mechanical-chemical method, the latter group showed lower value of roughness remarkably. 3. Mechanical stripping groups which were treated both coarse and fine instrument showed lower value of roughness as much as non treated group. 4. The use of Pumice for final polishing did not show significantly smoothening the stripped enamel surface any more.

• Journal of the Korean Society of Safety
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• v.26 no.2
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• pp.13-19
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• 2011

The magnetic polishing is the useful method to finish using magnetic power of magnet. That method is one of precision polishing techniques and has an aim of the clean technology using for the pure of gas and inside of the clean pipe. The magnetic abrasive polishing method is not so common for machine that it is not spreaded widely. There are rarely researcher in this field because of non-effectiveness of magnetic abrasive. Therefore, in this paper deals with development of the magnetic abrasive using Sr-Ferrite. In this development, abrasive grain GC used to resin bond fabricated low temperature. And Sr-Ferrite of magnetic abrasive powder fabricated that Sr-Ferrite was crused into 200 mesh. The XRD analysis result show that only GC abrasive and Sr-Ferrite crystal peaks detected which explains resin bond was not any more chemical reaction. From SEM analysis it is found that GC abrasive and Sr-Ferrite were strong bonding with each other by bond. The magnetic polishing is performed by polishing the surface of pipe by attracting magnetic abrasives with magnetic fields. This can be widely applied for finishing machinery fabrications such as various pipes and for other safety processes. In this paper, we could have investigated in to the changes of the movement of magnetic abrasive grain. In reference to this result, we could have made the experiment which is set under the condition of the magnetic flux density, polishing velocity according to the form of magnetic brush.

• Conservation Science in Museum
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• v.26
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• pp.119-142
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• 2021

The gilt-bronze-and-silver shoes, excavated from the Tomb of King Muryeong, revealed many defective parts, which constantly raised in-depth re-investigation and reporting. In that point, scientific treatment and analysis were conducted to investigate the manufacturing techniques applied. The conservation treatment was carried out with an emphasis on the restoration of the original form and joining parts. As a result, the upper part of the right shoe and some part of the back heel were joined, confirming the joining method and the number of rivet used for instep bonding. From the component analysis, it is presumed that the outer plate was gilded with mercury amalgam on pure copper, and pure silver was used for the inner plate. The main pattern of the gilt-bronze-and-silver shoes includes designs of phoenix, lotus, and six-petal flower, while the lotus pattern is high in terms of ratio. Thus, youngnaksa(twisted gilt-bronze thread), geumdongsa(gilt-bronze thread), wondujeong (rivet), and samyeonjeong(quadrangular cleats) were used for bonding each plate. Twisted gilt-bronze thread was used to join the inner and outer plates, while the center and rear of the inner plate were combined with only gilt-bronze threads. From the fact, it is presumed that the joining method was different whether the function was decoration or just bonding. Regarding the manufacturing process, traces of burnishing were confirmed on the outer surface of the gilt-bronze and silver shoes, but no burnishing traces were identified on the inner surface of the silver plate, which is likely to prove more importance put on the finishing of the outer plates rather than that of the inner.

• Journal of the Korean Wood Science and Technology
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• v.46 no.6
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• pp.735-747
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• 2018

Radon radiation exposures in home have been posed as a potential cancer hazard. This research aims to present the basic data of the indoor radon concentration level by examining the radon exhalation rates of wood species. Radon exhalation rates from five commonly used wood species in Korean wood building construction were measured with Continuous Radon Monitor (CRM), Model 1028 (Sun Nuclear Co., USA) using the Closed Chamber Method (CCM). The mass exhalation rate was observed to vary from $0.00089Bq{\cdot}kg^{-1}{\cdot}h^{-1}$ to $0.00181Bq{\cdot}kg^{-1}{\cdot}h^{-1}$, whereas the surface exhalation rate was observed to be $0.00677-0.01517Bq{\cdot}m^{-2}{\cdot}h^{-1}$. The radon exhalation rate of Quercus accutissima Carruth (white oak) which has the highest density showed the highest figure among the five wood species, on the other hand, the rest of four species showed similar results which were similar to the radon exhalation rates of wood in the U.S.A. and Canada. The average of the concentration measured by the CCM represented well up to the second half-life period (7.7 days). Because result of these small quantities seems to indicate that radon exhalation from the tested wood species has almost negligible impact, the main culprit of the high indoor radon concentration is clearly derived from the background of surrounding wood house. Therefore, as a safety precaution, infrastructures made of wood materials should be designed with the consideration of influx of radon and built accordingly. Furthermore, it is highly desirable that wood will be needed to use for furniture and interior finishing material in indoor environment.

• Current Photovoltaic Research
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• v.4 no.4
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• pp.159-163
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• 2016

Piled snow upon PV module interferes with Photoelectric Effect process through photovoltaic directly. As a result of this phenomenon, its generation efficiencies keep decreasing or are stuck at zero power generating status. In addition, PV facilities have been installed on those places such as water surface, roof-top, and other isolated places, dealing with conditions of "Securing high REC weighted value", "Difficulty of securing land" and so forth. Through this study, we are able to actualize the function of heating over PV modules when it snows. We adopted laminating method through heating film and modules, guaranteeing warranty more than for 25 years. Also we are trying remote control systemically, not by hardware control, to run parallel with automatic driving and monitoring system which enable to control operation time, insolation, amount of snowfall automatically. We applied analysis of actual proof to both snow removal PV system and general PV power system, and these led to bear power consumption analysis while snow-removing, and its comparison after finishing the task as "One stone, two birds." In the long run, we could carry out economic analysis against snow removal system, and this helps to verify the most maximized control method for snow removal conditons on a basis of weather information. this study shall let prevent people from negligent accidents, and improve power generation problems as mentioned from the top. Ultimately, we expect to apply this system to heavy snowfall regions in winter season in spite of its limited system installaion in Korean territory, initially.

• Journal of the Korean Society for Heat Treatment
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• v.7 no.3
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• pp.169-174
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• 1994

The reaction layer formed at interface between matrix and fiber has significant effects on the mechanical properties and behaviors of deformation m FRM. In this study, the mechanical properties and interfacial behaviors according to surface finishing on the fibers and according to heat treatment in FRM were investigated. FRM was fibricated by diffusion bonding method. In W/Al alloy composite and W/Al composite, W of which was coated with $WO_3$, the heat treatment was carried out thermal cycling method from 373K to 673K. In W/Al composite, W of which was coated with $WO_3$, growth of interface layer was hardly occured in spite of the increasing various thermal cycles. It was exhibited that oxidized W/Al composite were higher strength than non-oxidezed W/Al composite with the increasing thermal cycles. The compounds of fiber/matrix interface were analyzed into $WAl_{12}$, $WAl_7$, and $AlWO_3$, respectivly. Therefore the interfacial compounds of fiber/matrix seriously affected the mechanical properties and behaviors of deformation in FRM.

• Textile Coloration and Finishing
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• v.21 no.1
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• pp.1-9
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• 2009

A lot of research has been made over the recent decade to develop testing packages with antimicrobial properties to improve food safety. In this study, a new method, experimental device and technology for environmental corresponding packages of polypropylene (PP) film has been developed to provide effective temperature buffering during the transport/long-term storage of grains or foodstuffs from the supplier to the market. This quantitatively optimized mixing system enabled to produce PP films with the 700$\sim$1,400d (width;1.5$\sim$3mm, thickness;0.01$\sim$0.5mm). In the whole mixing systems, the finely-granulated inorganic illite and PP virgin chip for master batch (M/B) chip was calculated by digital measurement methods, and then the M/B chip for PP film was adapted through a air jet and PP grinding method. The prepared PP film was characterized with tensile strength and elongation, far infrared radiation (FIR) emissivity, antimicrobial activity and deodorization properties. The results revealed that the two differently grain-sized illite could be show homogeneously dispersed on PP chip surface, and as the increasing of illite content, the FIR emissivity and the anion emission rate of film was increasingly improved. In both of 325 and 1,500 mesh-sized illite contained PP chip, of course the antimicrobial activity was good. But the ultimate deodorization rate for ammonia gas of PP film were found to be approximately the same.

• Textile Coloration and Finishing
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• v.34 no.1
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• pp.68-75
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• 2022

The breathable film refers to a high-functional film that allows gas and water vapor to pass through very fine and sophisticated pores but not liquid. In this research, the breathable film was prepared based on linear low-density polyethylene (LLDPE) and CaCO₃ particles by extrude method. The LLDPE composite film containing CaCO₃ particles had excellent mechanical properties and functionalties. The drawing is a technologically simple and excellent method for improving the mechanical properties of composite films. In this work, the effects of draw ratio on morphology, crystallinity, pore size distribution, mechanical properties, and water vapor permeability of the films were examined. The results revealed that both surface morphology and breathability were affected by the influence of chain orientation and crystal growth with increasing the draw ratio. The mechanical properties were improved with increasing the draw ratio.