• Proceedings of the Materials Research Society of Korea Conference
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• 1997.05a
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• pp.27-27
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• 1997

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.219-222
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• 2003

Self-Assembled Monolayers(SAMs) by alkanethiol adsorption to thin metal film are widely being investigated for applications as coating layer for anti-stiction or friction reduction and in fabrication of micro structure of molecular and bio molecular. Recently, there have been many researches on micro patterning using the advantages of very thin thickness and etching resistance in selective etching of thin metal film of Self- Assembled Monolayers. In this report, we present the micromachining thin metal film by Mask-Less laser patterning of alknanethiolate Self-Assembled Monolayers.

• Restorative Dentistry and Endodontics
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• v.29 no.2
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• pp.185-190
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• 2004

자가산부식 접착제 (self-etching primer)는 법랑질과 상아질을 동시에 산부식과 프라이머 처리를 함으로 임상 시술 시간을 단축시킬 뿐만 아니라, 임상과정 중 발생할 수 있는 술자의 실수 및 타액등에 의한 오염의 가능성을 줄일 수 있는 장점을 가지고 있다. 그러나 약산을 이용한 산부식법이 법랑질에 대해 탈회효과 및 접착강도에 있어 논란이 되고 있다. 이에 본 연구에서는 인산을 이용한 추가적인 산부식 및 자가산부식 접착제의 적용시간을 달리할 경우 법랑질에 대한 접착강도의 변화를 알아보고자 하였다. 135개의 발거한 우치의 법랑질 면을 ＃600사포로 연마한 후 9개의 군으로 분류하였다. 각 군은 부가적인 32% 인산을 처리하지 않은 군 (1~3군), 15초간 처리한 군 (4~6군), 60초간 처리한 군 (7~9군)으로 나누고, 이를 다시 Clearfil SE Bond의 프라이머로 5초 (1, 4, 7군), 20초 (2, 5, 8군), 60초 (3, 6, 9군)간 처리한 군으로 분류하였다. 접착제 처리한 면에 Clearfil AP-X 복합레진을 접착하고 24시간 경과 후 전단응력 강도를 측정하였다. 결과는 One-way ANOVA 처리후 Duncan's multiple range test로 사후검증하였다. 동일한 자가산부식 프라이머 처리 시간을 가진 군에서 산 부식을 한 경우가 그렇지 않은 군에 비해 높은 접착강도를 나타내었으며 인산부식 시간의 차이에 의한 영향은 없었다.(1 < 4, 7군/ 2 < 5, 8군/ 3 < 6, 9군). 자가산부식제의 프라이머 적용 시간에 의한 효과는 1군(5초 적용)을 제외한 나머지 군의 경우 동일한 인산 처리군에서는 차이가 없는 것으로 나타났다.(1군 < 2, 3군/ 4＝5＝6군/ 7＝8＝9군). Clearfil SE Bond 접착제의 법랑질에 대한 접착강도는 부가적인 산부식을 통하여 증가시킬 수 있으며 프라이머의 적용 시간에 의한 효과는 제조자의 지시에 의한 시간 이상 적용할 경우 차이가 없는 것으로 나타났다.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.77-80
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• 2002

In this paper, InP-based HBTs have been optimally designed by numerical simulation and fabricated by the self-aligned process. The structure of HBT was designed in terms of the current gain*f$_{max}$ for the base and f$_{T}$*f$_{max}$ for the collector. The designed structure produced the current gain of about 50 and the cutoff frequency and the maximum oscillation frequency of 87GHz and 2940Hz respectively. In addition, we present a study of the vertical and lateral etching of InP with the mask sides parallel to the principal crystallographic axes, [0101 and (001). This etching characteristics arc used to fabricate self-aligned HBT structures with reduced parasitic effects.s.s.s.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.2
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• pp.77-79
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• 1992

We propose a self-aligned and double recessed technique for GaAs power MESFETs application. The gate length and the wide recess width are defined by a selective removal of the SiN layer using reactive ion etching(RIE) while the depth of the channel is defined by chemical etching of GaAs layers. The threshold voltages and the saturation drain voltage could be sucessfully controlled using this technique. The lateral-etched distance increases with the dry etching time and the source-drain breakdown voltage of MESFET increases up to about 30V at a pinch-off condition. The electrical characteristics of a MESFET with a gate length of 2 x10S0-6Tm and a source-gate spacing of 33 x10S0-6Tm show maximum transconductance of 120 mS/mm and saturation drain current density of 170-190mA/mm at a gate voltage of 0.8V.

• Restorative Dentistry and Endodontics
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• v.37 no.4
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• pp.207-214
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• 2012

Objectives: This study evaluated the influence of chlorhexidine (CHX) on the microtensile bonds strength (${\mu}TBS$) of resin core with two adhesive systems to dentin in endodontic cavities. Materials and Methods: Flat dentinal surfaces in 40 molar endodontic cavities were treated with self-etch adhesive system, Contax (DMG) and total-etch adhesive system, Adper Single Bond 2 (3M ESPE) after the following surface treatments: (1) Priming only (Contax), (2) CHX for 15 sec + rinsing + priming (Contax), (3) Etching with priming (Adper Single Bond 2), (4) Etching + CHX for 15 sec + rinsing + priming (Adper Single Bond 2). Resin composite build-ups were made with LuxaCore (DMG) using a bulk method and polymerized for 40 sec. For each condition, half of specimens were submitted to ${\mu}TBS$ after 24 hr storage and half of them were submitted to thermocycling of 10,000 cycles between $5^{\circ}C$ and $55^{\circ}C$ before testing. The data were analyzed using ANOVA and independent t-test at a significance level of 95%. Results: CHX pre-treatment did not affect the bond strength of specimens tested at the immediate testing period, regardless of dentin surface treatments. However, after 10,000 thermocycling, all groups showed reduced bond strength. The amount of reduction was greater in groups without CHX treatments than groups with CHX treatment. These characteristics were the same in both self-etch adhesive system and total-etch adhesive system. Conclusions: 2% CHX application for 15 sec proved to alleviate the decrease of bond strength of dentin bonding systems. No significant difference was shown in ${\mu}TBS$ between total-etching system and self-etching system.

• Proceedings of the KACD Conference
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• 2008.05a
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• pp.224-234
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• 2008

The purpose of this study was to compare the normal and two times of application time of six self-etching primers applied to enamel using microshear bond strength (uSBS) test and the finding of scanning electronic microscope (SEM). Crown of sixty human molars were bisected mesiodistally and buccal and lingual enamel of crowns were partially exposed and polished with 600 grit SiC papers. They were divided into one of two equal groups subdivided into one of six equal groups (n = 10) by self-etching primer adhesives. After the same manufacture's adhesive resin and composites were bonded on the enamel surface of each group, the bonded specimens were subjected to uSBS testing and also observed under SEM. In conclusion, generally two times of primer application time increased the enamel uSBS, especially with the statistical increase of bond strength in adhesives involving high-pH primers.

• Restorative Dentistry and Endodontics
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• v.28 no.2
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• pp.127-133
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• 2003

The object of this study was to compare the microleakage between various composite resin systems of multistep, one-bottle, and self-etching systems using electrical conductivity. After making class V cavities ($4{\times}3{\times}1.5{\;}mm$ around CEJ), they were bulk filled with three kinds of resins of A3. Teeth were storaged in a saline solution for one day, after then, they were finished and polished using Sof-Lex system. Another stress of thermocycling was made for 500 times from $5^{\circ}{\;}to{\;}55^{\circ}C$ with each dwelling time of 10 seconds. Electrical conductivity (microamphere, $\mu\textrm{A}$) was checked four times: before and after cavity preparation, after filing, after thermocycling. One-way ANOVA and 95% Scheffe Post Hoc test was used for checking any statistical difference among groups. Another 95% Paired Samples T-test was also used for estimating any significant difference within group after cavity filling or thermocycling. The results were as follows: 1 Every specimen showed various range of microleakage after filing. There was, however, no difference between composite resin systems. 2. All composite resin systems showed marked increase in microleakage with a thermocycling (p<0.05), there was, however, no difference between composite resin systems. 3. Although there was no significant difference between groups (p=0.078), one-bottle and self-etching systems seemed to be unstable than multistep system. Within the limits of this study, it was concluded that much more consideration should be needed when using thermally unstable one-bottle and self-etching systems that have multi-advantages from simplified step. More studies will be needed to solve these kinds of problems.

• Restorative Dentistry and Endodontics
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• v.27 no.3
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• pp.257-269
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• 2002

Objective : The purpose of this study was to evaluate the resin infiltration into dentin of one-bottle adhesive systems and self-etching primer bonded to Class V cavities using confocal laser scanning microscope(CLSM). Material and Methods : Forty Class V cavities were prepared from freshly extracted caries-free Human teeth. These teeth were divided into two groups based on the presence of cervical abrasion: Group I, cervical abrasion : Group II, wedge-shaped cavity preparation. Resin-dentin interfaces were produced with two one-bottle dentin bonding systems-ONE COAT BOND(OCB; Coltene$^R$) and Syntac$^R$SPrint$^{TM}$(SS; VIVADENT)-, one self-etching priming system-CLEARFIL$^{TM}$ SE BOND (SB : KURARAY)- and one multi-step dentin bonding system-Scotchbond$^{TM}$Multi-Purpose (SBMP, 3M Dental Products)-as control according to manufacturers' instructions. Cavities were restored with Spectrum$^{R}$(Dentsply). Specimens were immersed in saline for 24 hours and sectioned longitudinally with a low-speed diamond disc. The resin-dentin interfaces were microscopically observed using CLSM. The quality of resin-infiltrated dentin layers were evaluated by five dentists using 0~4 scale. Results : Confocal laser scanning microscopal investigations using primer labeled with rhodamine B showed that the penetration of the primer occurred along the cavity margins. Statistical analysis using one-way ANOVA followed by Duncan's Multiple Range test revealed that the primer penetration of the group 2(wedge-shaped cavity preparation) was more effective than group 1(cervical abrasion) and that of the gingival interfaces was more effective than the occlusal interfaces. In the one-bottle dentin bonding systems, the resin penetration score of OCB was compatible to SBMP, but those of SS and self-etching priming system, SB were lower than SBMP.

• Restorative Dentistry and Endodontics
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• v.33 no.3
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• pp.224-234
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• 2008

The purpose of this study was to compare the normal and two times of application time of six self-etching primers applied to enamel using microshear bond strength (uSBS) test and the finding of scanning electronic microscope (SEM). Crown of sixty human molars were bisected mesiodistally and buccal and lingual enamel of crowns were partially exposed and polished with 600 grit SiC papers. They were divided into one of two equal groups subdivided into one of six equal groups (n = 10) by self-etching primer adhesives. After the same manufacture's adhesive resin and composites were bonded on the enamel surface of each group, the bonded specimens were subjected to uSBS testing and also observed under SEM. In conclusion, generally two times of primer application time increased the enamel uSBS, especially with the statistical increase of bond strength in adhesives involving high-pH primers.