• Textile Coloration and Finishing
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• v.18 no.6 s.91
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• pp.43-48
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• 2006

Electrolytic water(EW), studied in recent decades in the Japan, Russia and United State of America, have shown promise as a method of disinfection whereby low levels of free chlorine, sodium hypochlorite, or hypochlorous acid may be produced in situ in Nacl-containing solution. These methods have shown promise in destruction of microorganisms in medical, dental environment, and in the agriculture and food industry. A recently EW treatment system was evaluated for reducing scouring agent and other surfactants in the washing and scouring process of textile industry Unfortunately, there is, to my knowledge, no serious studies of the properties of EW for textile industry In order to study the characteristics of EW and confirm the possibility of applications in textile industry processes, the pH, surface activity, penetration force, surface tension, and contact angle of EW was measured under various conditions. In general terms, What all this shows is that there is fundamental difference between the properties of EW and that of distilled water.

• Journal of the Korea Society of Computer and Information
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• v.21 no.5
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• pp.111-117
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• 2016

The purpose of this study is to analyze the changes in turnover intention according to the level of Burn out and the mediating effect in fire officer. Higher levels of emotional labor and turnover intention resulted in higher levels of burn out(p<0.05). We used the logistic regression analysis to compare change of turnover intention according to the level of burn out. In logistic regression analysis, largest mediating factor were working days per week, the number of moving case per a day, physical condition, emotional labor and the odds(Likely to with high turnover intention) was down by 38.9% after adjustment for mediating factors. The results of this study indicate that emotional labor was negatively impact on burn out in fire officer. To reduce the burn out and the turnover intention, it is necessary to do more efforts to improve work environment (working days per week, the number of moving case per a day and emotional labor) and management personal factor(physical condition) for the fire office should be made to reduce such negative effects.

• Korean Journal of Materials Research
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• v.14 no.12
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• pp.851-856
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• 2004

The aim of this study is to investigate the optimum drawing parameter for BAS121 welded tubes. The BAS121 aluminium alloy tubes with 25 mm in external diameter and 1.3 mm in thickness for heat-exchangers were manufactured by high frequency induction welding with the V shaped convergence angle $6.5^{\circ}$ and power input 55 kW. With increasing the reduction of area ($13,\;21\%$) by drawing, tensile strength was increased and elongation was decreased. With increasing the reduction of area by drawing, hardness in weld metal increased rapidly, while that of base metal increased slowly. In the specimen with the outer diameter smaller than 22 mm, hardness of weld metal was higher than that of base metal. The optimum drawing parameter of area reduction in BAS121 alloys was estimated about $13\%$ because of the work hardening of welds.

• Corrosion Science and Technology
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• v.9 no.6
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• pp.289-293
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• 2010

To investigate the corrosion behavior of tools steel surface in various coating film, the surface of hard coated Ti-Zr-N film on the tool steel by using magnetron-sputtering methods was researched using various experimental methods. STD 61 steels were manufactured by using vacuum furnace and solutionized for 1hr at $1050^{\circ}C$. Steel surface was coated with Ti-Zr-N film at $150^{\circ}C$ and 100W for 1h by using DC-sputtering equipment. Surface characteristics of Ti-Zr-N film coated specimens were investigated by OM, XRD, FE-SEM and nano-scratch tester. And corrosion behaviors of the coated specimen were investigated by polarization test and electrochemical impedance spectroscopy(EG&G Co, PARSTAT 2273. USA). It was found that Ti-Zr-N film coated sample had a thick coated layer and showed a good wear resistance and corrosion resistance of surface compared with ZrN and TiN coated sample. The corrosion resistance and mechanical property of Ti-Zr-N film coated STD 61 alloy increased as sputtering time increased.

• Corrosion Science and Technology
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• v.22 no.4
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• pp.257-264
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• 2023

Ti-6Al-4V alloys are mainly used as dental materials due to their excellent biocompatibility, corrosion resistance, and chemical stability. However, they have a low bioactivity with bioinertness in the body. Therefore, they could not directly bond with human bone. To improve their applications, their bone bonding ability and bone formation capacity should be improved. Thus, the objective of this study was to improve the bioinert surface of titanium alloy substrate to show bioactive characteristics by performing surface modification using wollastonite powder. Commercial bioactive wollastonite powder was successfully deposited onto Ti-6Al-4V alloy using a room temperature spray process. It was found that wollastonite-coated layer showed homogeneous microstructure and uniform thickness. Corrosion resistance of Ti-6Al-4V alloy was also improved by plasma electrolytic oxidation treatment. Its wettability and bioactivity were also greatly increased by wollastonite coating. Results of this study indicate that both plasma electrolytic oxidation treatment and wollastonite coating by room temperature spray process could be used to improve surface bioactivity of Ti-6Al-4V alloy substrate.

• Journal of the Korean Society for Heat Treatment
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• v.15 no.2
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• pp.76-81
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• 2002

The melt-spun amorphous $Fe_{77-X}P_{13}C_4B_4Al_2Mo_X$(x=4~10) and $Fe_{82-X}P_XC_4B_4Al_2Mo_8$(x=9~15) alloys were found to exhibit a large supercooled liquid region(${\Delta}T_x$) exceeding 40 K before crystallization. The largest ${\Delta}T_x$ for the glassy alloys containing Mo reaches as large as 65 K for the $Fe_{69}P_{13}C_4B_4Al_2Mo_8$ alloy. The corrosion behavior of the amorphous $Fe_{77-X}P_{13}C_4B_4Al_2Mo_X$(x=4~15) and $Fe_(82-X)P_XC_4B_4Al_2Mo_8$ (x=9~17) alloys were examined by electrochemical measurements in 9M $H_2SO_4$ solution at 303 K. The addition of Mo(or P) for replacing some portion of Fe is effective in improving the corrosion resistance of the investigated Fe-based glassy alloys. They are spontaneously passivated and have a wide passive region with low passive current density.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.6
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• pp.628-640
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• 2004

Statement of problem. Wear as a result of repeated closing/opening cycles may decrease the friction coefficient of screw head, threads, and other mating components and, consequently, resistance to opening gradually decreases. It may cause screw loosening, which is one of the most common failures in implant prosthesis. Purpose. The purpose of this study is to evaluate the changes on the head and thread surface of the abutment screws after repeated closing and opening through the examination of tested screws in SEM(scanning electron microscope). Materials and methods. Five species of abutments were selected (3i-three, Avana-two) respectively by two pieces. The implant fixtures were perpendicularly mounted in liquid unsaturated polyesther(Epovia, Cray Valley Inc.) with dental surveyor. Each abutment was secured to the implant fixture by each abutment screw with recommended torque value using a digital torque controller. The abutment screws were repeatedly tightened and removed 20 times with a digital controller. FESEM (field emission scanning electron microscope, Netherland, Phillips co., model:XL 30 SFEG) was used to observe changes of each part caused by repeatedly closing/opening expeiment. First, the Photomicrographs of pre-test screws provided by each manufacturer were taken. The changes of each screw were investigated after every fifth closing and opening experiment with FESEM. Scaning electron microscope photomicrographs of each screw were taken four times. Results. As the number of closing and opening was increased, the wear or distortion of hexed or squared slot that contacted with the driver tip was more severely progressed. Wear or distortion of hexed slot was more severe than that of squared slot and it was more remarkable in the titanium screw than in the gold screw. All the tested screws showed that the width in the crest of their screw thread decreased gradually as the test was proceeded. Conclusions. Conclusively, we recommend the clinical use of gold screw, a periodic exchanges of abutment screws and avoiding repeated closing/opening unnecessarily. We also suggest a more careful manipulation of the abutment screw and screw-driver and using of abutment screw with an acute-angled slot design rather than an obtuse-angled one. Finally, it is suggested that the new slot design and the surface treatment for enduring wear or distortion should be devised.

• Journal of Technologic Dentistry
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• v.32 no.4
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• pp.341-350
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• 2010

Purpose: This study focused on achieving desired shades by combining zirconia core with different thickness porcelain in order to make dental prostheses effectively. Methods: White and colored $LAVA^{TM}$ All Ceramic (3M-ESPE, Seefeld, Germany), and Zirkonzahn (Bruneck, Italy) Trans and prettau were used to have Zirconia. LAVATM Ceram (3M-ESPE, Germany) and ICE (Zirkonzahn, Italy) powder were used to have the porcelain. We made quadrilateral specimen of thickness 0.3mm, 0.5mm, 0.7mm and diameter 10 to use zirconia ceramics system of 2 kinds that color tone reappearance way is different and produced total 120 specimens to 4 experimental groups. We used Spectrophotometer to analyze color tone. Data's value getting by dispersal colorimetry period found L*, a*, b* value using Excel program. We used one-way ANOVA to use SPSS WIN 12.0 program. Results: All L*, a*, b* indexes of zirconia core and porcelain veneer in LAVA group and Zirkonzahn group were different. When you combine the white zirconia core of LAVA group with a porcelain veneer, the thickness of the porcelain must be more than 0.5mm to meet the standard target. When all the colored zirconia cores of LAVA group were combined with porcelain veneers, there was no significant difference from the standard target. When the zirconia cores of Zirkonzahn group are combined with porcelain veneers, the thinner thicknesses were closer to the standard tab than thicker thicknesses; however, there was a significant difference in all combinations, with Delta E* value indicating more than 3. Conclusion: When it comes to colored zirconia, which is the most popular, the thicknesses of both a core and a dentin veneer must be more than 0.3mm to get an appropriate shade. There is more possibility to get desirable shades when the thicknesses of a white core are thinner; however, they would be vulnerable to the environment and lose their color. When combine a zirconia core with a dentin veneer, using Zirkonzahn group needs more considerations in order to meet the standard target.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.6
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• pp.694-700
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• 2007

It is a gel type high functional toothpaste containing vitamin C, E, propolis extract and the rest of herb with a nanoemulsion state. Vitamin C, E is known as the material with an eminent anti-oxidation effect. Propolis is known as the material with an antimicrobial and anti-inflammatory effect. We have been succeeding in making nanoemulsion of vitamin C, E and propolis through the high pressure homogenizer using stable oil and lecithin and the gel type high functional tooth paste were made from nanoemulsion of vitamin C, E and propolis. We observed the process of wound protecting effect and cure effect for a wound of soft tissue, gingival tissue and mucous membrane showing ulcer and inflammation in oral cavity after applying a gel type high functional toothpaste to patient. As a result, the wound were healed very fast and any side effects were not shown. We confirmed that a gel type high functional toothpaste with nanoemulsion of vitamin C, E and propolis extract has good effect not only for wound healing but also for treatment of ulcer-like lesion in oral cavity. So we report our cases with review of literatures.

• The Journal of the Convergence on Culture Technology
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• v.8 no.1
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• pp.591-596
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• 2022

Various COVID-19 quarantine guidelines and measures are being taken by country at the WHO, but the number of confirmed cases has not decreased significantly. In order to prevent the inflow and outflow of COVID-19 through individual droplets, it is mandatory to wear a mask anytime, anywhere. However, as virus bacteria entering the mask amplify, it pollutes the mask and causes a disgusting smell. In this paper, a new method of preventing the spread of COVID-19 was proposed by sterilizing the mask with a dental gait spray introduced into the mask that has been used for a long time. Dental gargle water is usually produced by electrolysis of tap water, and the unstable ion water (HOCl) dissolved in water penetrates the cell barrier of various viruses and fails to act in its nucleus, causing water to self-purify. As a result of the experiment, when the mask used for a long time was washed with gargle water spray, the washed mask was dried after 10 minutes, and the smell of virus droplets or saliva almost disappeared. In particular, as a result of MOS testing the fit of the subjects who participated in the mask cleaning, it was excellent at 4.4 on average. Therefore, the mask was disposable, but if the spray was washed in the proposed method more than twice a day, the mask could be used in a comfortable state for more than a week.