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Nd-Yag 레이저 조사가 상아질의 내산성 및 레진의 전단결합강도에 미치는 영향
손흥규,정동진 大韓小兒齒科學會 1996 大韓小兒齒科學會誌 Vol.23 No.1
The purpose of this study was to examine the acid resistance and resin shear bond strength of Nd-Yag laser irradiated bovine dentin. To determine the most effective energy density of laser for improving acid resistance of bovine dentin, 120 specimen were divided into 6 groups consisting unlased control group and 5 experimental groups. The 100 specimens in the 5 experimental groups were exposed to a pulsed Nd-Yag laser under conditions ranging from 10 to 50J/㎠ at increments of 10J/㎠. All of the specimens were exposed to 0.5 N HCIO₄ solution containing 0.5% LaCl₃ for 30 seconds for demineralization. Dissolved calcium and phosphate concentrations in the demineralizing solution were determined by using an atomic absorption spectorphotometer and the UV spectrophotometer. To determine the resin shear bond strength of a pulsed Nd-Yag irradiated bovine dentin, the 60 specimens were divided into 6 groups. The Control group was etched with 10% phosphoric and for 15 seconds and rinsed thoroughly, mixture of primers A & B was applied 5 times on the dentin surface, and adhesive bonding resin was applied and light cured for 20 seconds, and composite cyliders were bonded to the dentin surface. For 5 experimental groups, after the laser irradiation, other procedures were same as control group except being not etched. All samples were measured for the shear bond strength by using 0.2 mm crosshead speed. SEM observations were made to examine the change of dentin surface after laser irradiation and to examine the fractured interface after the shear bond test. The results were as follows : 1. Th concentration of calcium dissolved from laser irradiated dentin at the energy densities of 10, 20, 30, and 40J/㎠ were significantly lesser than that of untreated control group (p<0.05). 2. The shear bond strength of 10J/㎠ group was higher than that of the control group even though it was statistically insignificant(p>0.05). The shear bond strength of the control and 10J/㎠ groups were significantly higher than those of 20, 30, 40 and 50J/㎠ groups(p<0.05). 3. Laser irradiation of the dentin reulted in crack formation at above 20J/㎠ of energy density and cracks were wider and deeper according to the increase of energy density as the energy density increases. 4. Following the shear bond strength test, bond failures occurred beneath the dentin surface in the 40 and 50J/㎠ groups. It could be concluded that it is most effective to use 10J/㎠ of energy density during while irradiating the dentin using an Nd-Yag laser.
정동진,Jeong, Dong-Jin 한국데이터베이스진흥원 2006 디지털콘텐츠 Vol.9 No.-
온라인게임 시장의 규모가 커지면서 소재 역시 다양해지고 있다. 그 중에서도 MMORPG에 비해 개발기간이 짧은 캐주얼 장르가 큰 인기를 모으고 있다. 캐주얼 게임의 성장세를 이끄는 분야는 단연 스포츠다. 진입장벽이 비교적 낮을 뿐만 아니라, 스포츠의 모토인 경쟁요소가 게임 속에 녹아들어 있기 때문. 이 중에서도 테니스를 소재로 한 게임으로는 플레이엔씨의 <스매쉬스타>를 필두로 엔덴게임스의 <겜블던>, 스타이리아의 <러브포티>가 있다. 최근 서비스를 중단한 <겜블던>을 제외한 <스매쉬스타>와 <러브포티>를 중심으로 테니스게임에 대해서 알아보자.