배달 미니 게임 개발:"최고의 웨이터를 꿈꾸며"

김정훈,정한교,김영옥,김중곤,박정윤,윤진성,김경식 호서대학교 반도체제조장비국산화연구센터 2001 반도체장비학술심포지움 Vol.2001 No.-

본 미니 게임은 웨이터라는 직업을 모티브로 하여서 남녀노소 누구나 재미를 느낌과 동시에 기억력 향상시켜 주는 게임제작이라는 목적아래 제작되었다.본 논문에서는 이 게임의 제작과정을 기술하고자 한다.이 게임은 제3회 AGC(한국 아마추어 게임제작 공모전)에서 우수 작으로 선정되었다.

치과재료와 환경호르몬

김교한 대한치과기재학회 1998 대한치과재료학회지 Vol.25 No.3

Sandblast 처리한 상아질면의 접착에 관한 연구

김교한,나환옥,황성욱 경북대학교 의학연구소 2000 경북대학교병원의학연구소논문집 Vol.4 No.1

Dentin adhesion was studied on sandblasted dentin with 4-MET/MMA-TBB resin. The effect of change of air pressure, with or without pretreatment and primer on tensile bond strength, was mainly investigated. In the effect of air pressure at sandblast treatment, the higher pressure showed the increase of tensile bond strength. The pretreatment with 10-3 solution after sandblast treatment increased tensile bond strength in the almost conditions. Application of primer also increased the tensile bond strength, confirmed the effect of primer application after sandblast treatment. Alumina particle was not found on the dentin surface in the SEM and EDAX examination.

치과주조용 저카라트 금합금의 시효경화

김형일,김종렬,안호경,장명익,설효정,김교한 대한치과기재학회 1997 대한치과재료학회지 Vol.24 No.2

The age-hardening behavior of a commercial dental casting low-carat gold alloy was investigated by means of differential thermal analysis, hardness test, optical microscopic observation and X-ray diffraction study. The following results were obtained. 1. By the isothermal aging of this alloy at 300∼400℃, the hardness increased markedly at the initial stage and continued to increased gradually for the time, and then decreased dractically after longer aging time. 2. The hardening was attributed to the formation of the metastable AuCu I' ordered phase from the α matrix. 3. The overaging with softening was attributed to the precipitation of the fine lamellar structure which was composed of the Ag-rich α1 and AuCu I ordered phases.

치과 주조용 저금합금의 개발에 관한 연구

김교한,김형일 대한치과기재학회 1996 대한치과재료학회지 Vol.23 No.2

The purpose of this study was to develop the dental casting low carat gold alloys based upon Au-Ag-Cu ternary alloy. Three types of low carat gold alloy containing 46, 55 and 66wt. % of gold, content respectively, which were balanced with total amount of Au plus Ag of 74wt. %, were melted and casted to evaluate the mechanical properties, corrosion resistance, melting range and cytotoxicity. The obtained results were summarized follows : ·In mechanical properties, the type K-Ⅱalloys, which was increased in the amount of Pt component, showed 115MPa of yield strength, 400MPa of ultimate tensile strength and 150 of vicker's hardness value and these values are higher than those of K-Ⅰ, K-Ⅲ alloy of 30% in yield strength, 50% in ultimate tensile strength and 10% in hardness value. ·Age hardening effect was confirmed in all three alloys. ·Melting ranges of these alloys were in the range of 910-1050℃ ·Higher corrosion resistance was confirmed in the potential range of oral cavith. ·The cytotoxicity of alloys was evaluated by the cell growth and morphologic changes, Each alloy showed normal growth rate and cellular morphology.

전기화학법에 의해 형성된 Ti 양극산화피막의 특성

김태영,손원우,권태엽,강인규,김교한 大韓齒科器材學會 2002 대한치과재료학회지 Vol.29 No.3

The effects of electrolyte concentration and current density on the behaviour of volt-time curve of the anodizing, morphology, roughness, crystallinity and composition of the oxide layer were studied. Microstructural morphology, crystallinity, composition and surface roughness of oxide layer were analyzed by observed by scanning electron microscopy(SEM) and X-ray diffractometry(XRD), Energy-dispersive spectrometer(EDS), Electron Probe Micro Analyzer(EPMA)and roughness tester, respectively. The results of this study showed that the voltage incresed as the anodizing time increase. The growth of the oxide film developed a barrier layer to a pore-like layer with an increasing of current density, arising a spark discharge. On the morphology of anodic oxide layer the number and size of porosity was increased by increasing anodizing time at a constant concentration of electrolyte. The size of porosity and the roughness of the anodic oxide layer were increased by the increasing of concentration of electrolyte. The anodic oxide layer obtained in the conditions of this experiment was identified as anatase. The crystallinity of oxide layer was decreased by increasing the concentration of electrolyte at constant current density, and increased by the increasing current density at constant electrolyte concentration. In the EPMA analysis of anodic oxide layer, the concentration of phosphorous was increasing the electrolyte concentration and increasing the final voltage at constant electrolyte concentration, The ratio of O/Ti of the oxide layer obtained in this experiment was near 2 confirming this oxide layer was TiO₂

Vital Bleaching이 법랑질 접착에 미치는 영향

김종해,권태엽,권용훈,김교한 大韓齒科器材學會 2003 대한치과재료학회지 Vol.30 No.4

The objective of this in vitro study was to evaluate the effect of bleaching on the composite to enamel bond and surface hardness change. Extracted human premolars were treated with 35% hydrogen peroxide (Sigma Chemical Co, USA) for 1hr/day at 0, 3, 6 and 9 day respectively. For the obsrvation of surface mophology alteration due to the treatment with hydogen peroxide, a SEM (S-4300, Hitachi, Japan) was used. The specimens were ground flat using serial SiC papers and ground ultra-finely using a 0.1㎛ diamond compound paste. To measure the microhardness, five non-carious premolars were ground using SiC papers and ten indentations were made on the surfacd with Vickers hardness tester (FM-7 FUTURE-TEC Inc., Japan). To evaluate shear bond strength, composite was bonded with One Up Bond-F, Prompt L-Pop, AQ Bond to the non-bleached and bleached enamel surface of sixty non-carious premolars. The bonding procedure is postponed for 1 week after bleaching and shear bond strength was measured. All specimens with a SEM. Bleaching created some enamel porosity but the teeth showed nonsignificant morphological chonge as bleaching time increased from SEM analysis. Most microhardness change occured on the first day of bleaching. Bleaching with 35% hydrogen peroxide did not result in significant change in the shear bond strength of composite resin to enamel. In the shear bond strength test, the fractured surfaces of specimens showed mixed adhesive and cohesive failure behavior.

Al-CuAl₂ 共晶合金의 一方向凝固組織과 機械的性質

金敎漢 영남이공대학 1982 論文集 Vol.11 No.-

The microstructure and mechanical properties of unidirectionally solidified Al-Cu eutectic alloys have been studied to research the effects of the growth rate. The temperature gradient is 80℃/cm and growth rate is controlled from 0.833mm/min to 18.75mm/min. The results obtained are as follows. 1) The interlamellar spacing is propertional to the growth rate and ;OR was 7.769x10^-5 mm^3/min. 2) The faster growth rate causes the higher mechanical strength. 3) Interrelationship between interlamellar spacing and hardness coincide with the Hall-Petch type equation.

치과용 Au-Ag-Cu-Pd 합금의 시효경화특성

김형일,김영근,장명익,김교한 대한치과기재학회 1997 대한치과재료학회지 Vol.24 No.1

The relationship between the isothermal age-hardening behavior and the phase transformation process in a dental casting Au-Ag-Cu-Pd alloy was investigated by means of hardness test, X-ray diffraction study. 1. The isothermal age-hardening behavior in the 350∼450℃ temperature range showed a similar tendency in the changes. However, the initial hardening was faster and the maximum hardness was higher and the overaging with softening was slower on aging at the lower temperature. 2. By the isothermal aging at 350∼450℃, the metastable Ag-rica α₁’and AuCu Ⅰ’orderd phases were formed from the supersaturated α phase prior to the final formation of the equilibrium Ag-rich α₁’and AuCu Ⅰordered phases. 3. By aging at 450℃, the age-hardening was attributed to the lattice strains of the parent phases resulting from the transformation of the αphase resulting from the transformation to the metastable phases. The X-ray diffraction peaks of the αphase showed a distinct shift toward both the high and low diffraction angles during transformation.

α+β型 Ti-6Al-4V 合金의 機械的 性質 및 破壞靭性에 미치는 二重溶體化 處理의 影響

金敎漢 慶北大學校 齒科大學 1989 慶北齒大論文集 Vol.6 No.1

Double solution treatment method was used to investigate the effect of microstructure on mechanical properites and fracture toughness of α+β type Ti-6Al-4V alloy. In solution treatment, equiaxed α phase is resulted by 1st solution treatment and acicular α phase by 2nd solution treatment. So two conditions were considered to know the effect of equiaxed and acicular α pahse. First condition is that the amount of acicular α and equiaxed α is changed relatively while total α phase amount is keeped constant. Second one is that the amount of aciclar α phase is changed while equilaxed α ratio is keeped constant. By examined the mechanical properties and fracture toughness of double solution treatmented sepcimens, following results are obtained. 1. Yield strength, elongation and reduction of area have almost same values at double solution treatmented conditions. 2. Fracture toughness shows its the highest value at the condition that the difference between 1st and 2nd double soulution treatment is 100 degree. 3. Fracture toughness of Ti-6Al-4V alloy is affected by the morphology of acicular α phase, such that, when acicular α phase is arranged with block unit, fracture toughness is increased.