• 대한치과의사협회지
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• 제49권5호
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• pp.265-278
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• 2011

The introduction of zirconia-based materials to the dental field broadened the design and application limits of, all-ceramic restorations. Most ceramic restorations are adhesively luted to the prepared tooth, however, resin bonding to zirconia components is less reliable than those to other dental ceramic systems. It is important for high retention, prevention of microleakage, and increased fracture resistance, that bonding techniques be improved for zirconia systems. Strong resin bonding relies on micromechanical interlocking and adhesive chemical bonding to the ceramic surface, requiring surface roughening for mechanical bonding and surface activation for chemical adhesion. In many cases, high strength ceramic restorations do not require adhesive bonding to tooth structure and can be placed using conventional cements which rely only on micromechanical retention. However, resin bonding is desirable in some clinical situations. In addition, it is likely that strong chemical adhesion would lead to enhanced long-term fracture and fatigue resistance in the oral environment.

• 한국재료학회지
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• 제16권2호
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• pp.99-105
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• 2006

This paper reports an improved bonding method using the IPA (isopropyl alcohol) assisted low-temperature bonding process for the PMMA (polymethylmethacrylate) micro CE (capillary electrophoresis) chip. There is a problem about channel deformations during the conventional processes such as thermal bonding and solvent bonding methods. The bonding test using an IPA showed good results without channel deformations over 4 inch PMMA wafer at $60^{\circ}C$ and 1.3 bar for 10 minutes. The mechanism of IPA bonding was attributed to the formation of a small amount of vaporized acetone made from the oxidized IPA which allows to solvent bonding. To verify the usefulness of the IPA assisted low-temperature bonding process, the PMMA micro CE chip which had a $45{\mu}m$ channel height was fabricated by hot embossing process. A functional test of the fabricated CE chip was demonstrated by the separation of fluorescein and dichlorofluorescein. Any leakage of liquids was not observed during the test and the electropherogram result was successfully achieved. An IPA assisted low-temperature bonding process could be an easy and effective way to fabricate the PMMA micro CE chip and would help to increase the yield.

• 대한심미치과학회지
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• 제23권2호
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• pp.58-69
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• 2014

In case of esthetic restorative procedure with zirconia restoration, we have to use resin cement because of not only just for retention but also esthetic reason. In such a clinical situation, we have to consider two bonding interfaces, one is tooth surface to resin cement and the other is zirconia surface to resin cement. There is well established bonding protocol between tooth surface to resin cement, but bonding protocol of zirconia surface to resin cement is still controversial. In scientific point of view, there are two mechanism for bonding of zirconia restoration.. One is mechanical retention and the other is chemical adhesion. However, we have three different options for bonding of zirconia restoration in clinical situation; 1) Tribo-chemical coating with silica and silane coupling agent 2) Zirconia primer with phosphate chemistry 3) Self-adhesive resin cement with phosphate chemistry.

• Bulletin of the Korean Chemical Society
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• 제35권6호
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• pp.1897-1900
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• 2014

• 대한치과교정학회지
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• 제24권4호
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• pp.957-967
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• 1994

The purpose of this study was to evaluate the effects of different bases of ceramic brackets on shear bond strength and to observe failure patterns of bracket bondings. Lower bicuspid brackets whose bases designed for the macromechanical and silane treated chemical bonding those for silane treated chemical bonding, those for micromechanical bonding, and those for macromechanical bonding were tested as experimental groups, and foil mesh-backed metal brackets as a control group. All the brackets were bonded with $Mono-Lok\;2^{(TM)}$ on the labial surface of extracted human lower bicuspids after etching the enamel with $38\%$ phosphoric acid solution for 60 seconds. The shear bond strengths were measured on the universal test machine after 24 hours passed in the $37^{\circ}C$ water bath. The gathered data were evaluated and tested by ANOVA and Duncan's multiple range test, and those results were as follows. The shear bond strengths of brackets for macromechanical and chemical bonding, those for chemical bonding, and those for micromechanical bonding were not different (p>0.05), but showed statistically higher than those of metal bracket and those of ceramic bracket for micromechanical bonding(p<0.05). The shear bond strengths of ceramic bracket for micromechanical bonding showed statistically lower than those of metal bracket(p<0.05). The enamel fractures and/or ceramic bracket fractures were observed in the cases of higher bond strength than that of metal bracket. These results supported that silane treated base of ceramic bracket show higher shear bond strength than that of metal bracket, and suggested that micromechanical form of ceramic bracket bases show higher shear bond strength than that of macromechanical form.

• Bulletin of the Korean Chemical Society
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• 제27권12호
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• pp.2045-2050
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• 2006

The interstitial hydrogen bonding in NiTi solid and its effect on the metal-to-metal bond is investigated by means of the EH tight-binding method. Electronic structures of octahedral clusters $Ti_4Ni_2$ with and without hydrogen in their centers are also calculated using the cluster model. The metal d states that interact with H 1s are mainly metal-metal bonding. The metal-metal bond strength is diminished as the new metal-hydrogen bond is formed. The causes of this bond weakening are analyzed in detail.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제23회 추계학술대회 논문집
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• pp.215-222
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• 2004

본 논문에서는 고분자의 바인더와 고체불질 사이의 결합력을 증진시켜 물성을 향상시키는 역할과 화학결합에 의한 두 재질간의 접착력을 향상시킬 목적으로 사용되는 Aziridine계 bonding agent를 합성하여 이화학 특성을 분석하고 이를 라이너에 적용하였을 때 불성 및 접착력 특성에 관한 연구를 하였다. 비교 실험을 진행하기 위해 미국 3M사에서 제조한 HX-868을 통일한 조건에서 사용했고 미국규격에 규정된 항목과 각 항목에 대한 표준화된 방법으로 분석하였다. 그 결과 국내기술로 합성한 HX-868이 미국에서 제조된 HX-868과 통일한 품질 수준으로 갖는 것으로 평가되었다.

• Bulletin of the Korean Chemical Society
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• 제23권8호
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• pp.1157-1159
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• 2002

• Bulletin of the Korean Chemical Society
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• 제24권5호
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• pp.545-546
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• 2003

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2001년도 추계학술발표논문집
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• pp.183-199
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• 2001

Alternative way of shaping fibers suitable for papermaking was introduced. Impact refining, which was done simply by hitting wet fibers with a metal weight vertically, was intended to keep the fibers from shortening and to cause mostly internal fibrillation. Virgin chemical pulp, its recycled one and OCC were used in the experiment. It was noticed from the experiment that impact refining on virgin chemical pulp kept the fiber length and Increased bonding properties greatly, However, in the recycled fibers from the chemical pulp, fiber length and bonding properties were decreased. In OCC, which seems to contain fractions of semi-chemical pulp and mechanical pulp (GP), and which is recycled pulp from corrugated boxes, fiber length and bonding properties were decreased disastrously. We believe recycled cellulosic fibers (recycled chemical pulp and OCC in this case), which went through hornification, were less resistant to the mechanical impact than virgin chemical pulp. For virgin chemical pulp, impact refining allowed no significant fiber length shortening, high WRV, and high mechanical strength.