• 대한치과교정학회지
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• 제34권4호
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• pp.343-349
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• 2004

레이저를 이용한 브라켓 제거 술식은 발생하는 열이 국소적이며 조절 가능하고 레이저 조사와 동시에 브라켓 제거시 기구가 뜨거워지지 않으며 브라켓 디자인에 상관없이 여러 형태의 브라켓에 적용이 가능하다는 장점을 가지고 있다. 그러나 아직까지는 치아에 안전한 레이저 강도가 명확히 밝혀지지 못한 상태이다. 따라서 본 연구에서는 토끼의 중절치에 도재 브라켓을 부착한 후 Nd-YAG laser를 여러 가지 강도로 조사한 후 브라켓을 Weingart 겹자로 탈락시켜 5일이 경과한 때의 치수의 조직학적 변화에 대해 관찰한 결과 다음의 결과를 얻었다. 1. Nd-YAG 레이저의 조사 강도가 3-5W이고 조사시간이 3초인 그룹에서 도재 브라켓이 용이하게 제거되지 않았으며 조사 강도가 5W인 그룹에서 한 개의 브라켓에 결찰익면 파절이 나타났다. 이때 치수의 조직학적 검사상 비정상적인 소견은 관찰되지 않았다. 2. Nd-YAG 레이저의 조사 강도가 7-l3W이고 조사시간이 3초인 그룹에서 도재 브라켓을 쉽게 제거할 수 있었으며 브라켓의 파절양상은 보이지 않았다 이때 치수의 조직학적 검사상 경미하고 가역적인 염증 반응이 관찰되었다. 위의 소견은 모두 가역적인 변화이며 치수의 변성이나 괴사의 위험은 없었다 결론적으로 레이저를 이용하여 도재 브라켓을 제거하는 방법은 적절한 범위의 강도와 조사시간 내에서 시행되었을 때 치수의 변성이나 비가역적인 반응을 초래하지 않고 브라켓과 접착 수지의 결합력을 약화시켜 도재 브라켓의 제거를 용이하게 해주며 브라켓 제거 시 파절을 방지하여 도재 브라켓의 재활용 가능성을 높이는 방법이라 생각된다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.1056-1059
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• 2001

These days, as dynamic function and special properties to compare traditional material, $Al_20_3$ ceramic use all over the industry. But it is very difficult to process because of high hardness and brittleness. Therefore, in this paper, it was investigated that laser process parameter which can produce appropriate quality of $Al_20_3$ ceramic microhole machining.

• 한국광학회:학술대회논문집
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• 한국광학회 2007년도 동계학술발표회 논문집
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• pp.30-31
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• 2007

• 한국광학회:학술대회논문집
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• 한국광학회 2008년도 하계학술발표회 논문집
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• pp.153-154
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• 2008

• 한국광학회:학술대회논문집
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• 한국광학회 2005년도 하계학술발표회
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• pp.228-229
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• 2005

• 한국세라믹학회지
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• 제46권5호
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• pp.456-461
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• 2009

Chemical composition and status of chemical bonding of the YAG($Y_3Al_5O_{12}$) ceramics after the exposure to fluorine plasma have been investigated using X-ray photoelectron spectroscopy, with the analysis on its erosion behavior. On the surface, F showed the maximum content, decreasing with depth, meanwhile the cation composition remained almost constant, irrespective of the position. The peaks due to Y in the reaction layer consisted of two kinds, showing the Y-O and Y-F bonds. These surface modifications under fluorine plasma seem to promote the erosion of the YAG ceramics. Excess addition of $Al_2O_3$ or $Y_2O_3$ into stoichiometric YAG produced 2nd phases of $Al_2O_3$ and $YAlO_3$, respectively, resulting in the slight difference in the local erosion rates. But, the overall average erosion rate was not sensitive to such excess additions of $Al_2O_3$ or $Y_2O_3$.

• The Korean Journal of Ceramics
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• 제6권3호
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• pp.206-208
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• 2000

0.65 mol% MgO-doped LiNbO$_3$single crystals were grown by CZ method. The obtained single crystals were colorless and transparent. Noncritically phase-matched second harmonic generation (SHG) of 532-nm radiation from 1064-nm in MgO-doped LiNbO$_3$has been investigated by using pulsed Nd:YAG laser. The phase-matching temperature was room temperature. SHG conversion efficiencies were typically achieved higher than 50% at the phase-matching temperature with no photorefractive damage in the region of fundamental power density which was used in this experiment. The thermo-birefringence coefficient and the electro-birefringence coefficient of SHG were calculated from the temperature phase-matching profile with the electric field.

• 한국레이저가공학회지
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• 제3권2호
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• pp.25-33
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• 2000

One of perspective direction of microfabrication is direct laser writing technology that allows to create metal, semiconductive and dielectric micropatterns on substrate surface. In this work, a two step method, the combination of seed forming process, in which metallic Al seed was selectively generated on AlN ceramic substrate by direct writing technique using a pulsed Nd : YAG laser and subsequent electroless Ni plating on the activated Al seed, was presented. The effects of laser parameters such as pulse energy, scanning speed and pulse frequency on shape of Alseed and conductor line after electroless Ni plating were investigated. The nature of the laser activated surface is analyzed from XPS data. The line width of this metallic Al and Ni is analyzed using SEM. As a results, Al seed line with 24㎛ width and 100㎛ isolated line space is obtained. Finally, laser direct writing can be applied in the field between thin and thick film technique in electronic industry.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2000년도 춘계총회,특별강연,심포지움,연구발표회
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• pp.61.1-61.1
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• 2000

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.99-102
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• 1999

A mixture which was made from organic gel, glass powder and ceramic powder was masklessly etched for fabrication of barrier rib of PDP(Plasma Display Panel) by focused Ar$^{+}$ laser( λ =514 nm) and Nd:YAG(λ =532, 266 nm) laser irradiation at the atmosphere. The depth of the etched grooves increases with increasing a laser fluence and decreasing a scan speed. Using second harmonic of Nd:YAG laser, the threshold laser fluence was 6.5 mJ/$\textrm{cm}^2$ for the sample of PDP barrier rib softened at 12$0^{\circ}C$. The thickness of 130 ${\mu}{\textrm}{m}$ of the sample on the glass was clearly removed without any damage on the glass substrate by fluence of 19.5 J/$\textrm{cm}^2$....