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구강균 Streptococcus mutans KDJ-50에 대한 정향의 향균효과
곽동주,남상용,정석민,Kwak, Dong-Ju,Nam, Sang-Yong,Chung, Suk-Min 대한치과기공학회 2001 대한치과기공학회지 Vol.23 No.1
This study was conducted to find antibacterial agent against growth of dental caries bacteria. St. mutans KDJ-50 from various medicinal plants of which safety was indetified. Medicinal plants used in this study was dried and grinded after purchased at Daegu yakryung sijang and Kyungsan jungang sijang. Medicinal plants extracted with 80% ethanol at boiling point for 3 hrs was used as antibacterial agent after freeze dried. This study was conducted to find antibacterial agent against growth of dental caries bacteria. St. mutans KDJ-50 from 32 medicinal plants of which safety was indetified. The result of using paper disc method. Caryophylli Flos. Coptidis Rhizoma. Phellodendri Cortex. Schizamdrae Fructs. Myristicae Semen, Crataegi Fructus and Acori Graminei Rhizoma was selected as antibacterial agent. The result of viable cell counting method. the antibacterial activity of Caryophylli Flos was highest among tested 7 medicinal plants followed by Phellodendri Cortex and Coptidis Rhizoma. The extinction effect of the St. mutans by Caryophylli Flos was shown with the addition of 0.5 (w/v) in the medium. The high antibacterial activity was acquired at high extraction temperature and long extraction temperature. The antibacterial activity of Caryophylli Flos was not effected by the concentration of ethanol.
곽동주 대구보건대학 1994 대구보건대학 論文集 Vol.14 No.-
Effects of hydrogenation-dehydrogenation treatment on pure Ti and Ti-0.15pd alloy were studied. Pure Ti and Ti-0.15Pd alloy were conducted solution treatment at 950℃, respectively and then done hydrogenation dehydrogenation treatment. Then, the relationship between hydrogen treatment condition and X-ray diffraction patterns, i.e. the microstructure factor is examined. Ti-hydride precipitates mainly at α - β interface and also in α phase. Microstructure Ti alloy shows finer than that of pure titanium in hydrogenation and dehydrogenation treatments. Ti-0.15Pd alloy carried out solution treatment at 950℃, the transformation of α martensite was occured. Hydrogen absorption of Ti-0.15Pd alloy was higher than that of pure titanium. Dehydrogenation temperature in titanium alloy occured approximately at 400-562℃. Hydrogen tretment was used as a temporary alloying element modifying the microstructure of tianium in order to enhance fatigue behavior for partial denture.
도재소부용 금합금에서 인듐, 주석 첨가가 금속-도재계면 특성에 미치는 영향
남상용,곽동주,정석민,Nam, Sang-Yong,Kwak, Dong-Ju,Chung, Suk-Min 대한치과기공학회 2001 대한치과기공학회지 Vol.23 No.1
This study was performed to observe the micro-structure change of surface, behavior of oxide change of element, the component transformation of the alloy and the bonding strength between the porcelain interface in order to investigate effects of indium, tin on interfacial properties of porcelain fused to low gold alloy. Hardness of castings was measured with a micro-Vicker's hardness tester. The compositional change of the surface of heat-treated specimen was analyzed with an EDS and an EPMA. The interfacial shear bonding strength between alloy specimen and fused porcelain was measured with a mechanical testing system(MTS 858.20). The results were as follows: 1) The hardness value of alloy increased as increasing amount of indium addition. 2) The formation of oxidation increased as increasing indium and tin contents after heat treatment. 3) Diffusion of indium and tin elements increased as increasing indium and tin contents in metal-porcelain surface after porcelain fused to metal firing. 4) The most interfacial shear bonding strength was increased as increasing a composition of adding elements, and a heat-treatment time, and an oxygen partial pressure. From the results of this study it was found that the addition of alloying elements such as indium and tin increase hardness of as-cast alloy, produce surface oxide layer of adding elements by heat-treatment which may improve interfacial bonding strength between alloy and porcelain.
도재소부용 금합금의 열처리에 따른 기계적 성질 및 미세조직 변화에 관한 연구
남상용,곽동주,차성수,Nam, Sang-Yong,Kwak, Dong-Ju,Cha, Sung-Soo 대한치과기공학회 2009 대한치과기공학회지 Vol.31 No.4
The purpose of this study was to observe the change of mechanical property and microstructure in porcelain fused to gold alloy by heat treatment. PFG alloys are composed with Au-Pd-Ag alloy of the additional elements with indium, tin and copper. Specimens were tested in hardness using vicker,s micro-hardness tester and the surface micro structural changes were analysed by SEM and EDS. The results were as fellows: 1. The vickers hardness showed highest in Au-Pd-Ag alloy of the additional element with tin. 2. By hardening-oxiding result, the vicker,s hardness increased in additional element with tin but there was no significant difference in additional elements with indium and copper. 3. The surface oxide layer of Au-Pd-Ag alloy with added indium and tin increased but there was small change in additional element with copper. 4. The elements of indium and tin increased with increasing heat treatment in the surface alloy.
Full Zirconia Crown용으로 사용되는 block의 제조사의 굴곡강도와 임상작업후의 굴곡강도에 관한 연구
정효경,곽동주,Jung, Hyo-Kyung,Kwak, Dong-Ju 대한치과기공학회 2011 대한치과기공학회지 Vol.33 No.4
Purpose: The purpose of this study was to evaluate flexural strength of full zirconia crown using block after clinical work. Methods: The three point bending test was used to measure the flexural strength of zirconia block. Statistical analysis was done using the Statistical Package for Social Sciences version 19.0 for Windows. As for the analysis methods, the study used analysis of variance, Tukey's test. Results: The ave Rage value of flexural strengths of WIELAND, Zirkonzahn, Hass, D-MAX were 516.2 MPa, 612.6MPa, 566.2MPa, 744.6MPa. The ave Rage value of Surface Roughness of WIELAND, Zirkonzahn, Hass, D-MAX were 0.39Ra, 0.33Ra, 0.33Ra, 0.47Ra. Conclusion: Flexural strength of zirconia block decreased after clinical work. Flexural strength of zirconia block is equal to or higher than flexural strength of dental metal, so zirconia block can be used as dental material.