• 대한치과교정학회지
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• 제41권6호
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• pp.411-422
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• 2011

브라켓의 접착에 의한 입술 주위 연조직의 변화를 평가하기 위하여 심한 골격적 부조화가 존재하지 않는 18세 이상, 29세 미만의 성인 환자 중 포괄적 교정 치료를 위하여 상, 하악 치아의 순측에 브라켓을 접착한 45명을 대상으로 3차원 레이저 스캐너를 이용하여 브라켓의 접착 직전과 직후의 3차원 입체 영상을 획득하였다. 브라켓의 접착 전후 입술 및 입술 주위 연조직의 변화를 3차원 좌표계 상에서 분석하였다. 3차원 변화량(distance: 동일 계측점 간의 변화에 대한 최단 거리)에서 유의성을 보인 모든 계측점에서 전방 변화량이 가장 크게 나타났으며, 측면 계측점들은 측방으로 유의성 있는 변화가 나타났다. 상순의 계측점들은 상방으로, 하순의 계측점들과 B'는 하방으로 유의성 있는 변화가 나타났다. 하순의 Li (labrale inferius)에서 1.39 mm로 가장 큰 변화가 나타났고 ($p$ < 0.01), Li Rt (labrale inferius right), Li Lt (labrale inferius left)에서 1.15 mm, 1.09 mm의 변화가 나타났다 ($p$ < 0.01). 상순의 양측 ULP (upper lip point), Ls (labrale superius), Ls Rt (labrale superius right), Ls Lt (labrale superius left)에서 0.81 mm, 0.85 mm, 0.82 mm, 0.97 mm, 0.92 mm의 변화를 보여 ($p$ < 0.01), 하순에 비하여 상순의 변화가 작게 나타났다. 양측 Ch (cheilion)과 Stm (stomion)에서 1.17 mm, 1.16 mm, 1.02 mm ($p$ < 0.01), Sn (subnasale)와 B' (soft tissue B point)에서 0.46 mm, 0.63 mm ($p$ < 0.01, $p$ < 0.05)의 변화가 나타났다. 브라켓의 종류에 따른 연조직 변화량은 차이가 나타나지 않았다. 이상의 결과는 성인 교정 환자에서 브라켓의 접착에 의한 입술 및 입술 주위 연조직 변화의 예측에 참고 자료가 될 것이다.

• 대한치과보철학회지
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• 제38권1호
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• pp.1-11
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• 2000

Relining and rebasing are essential for long-term success and oral health in removable prosthodontics. Major features of failures between metal base and relining resins are adhesive failure due to lack of chemical bonding. The purpose of this study was to find a better metal primer and metal surface treatment method that enhance the bonding strength with relining resin materials. The surfaces of ticonium alloys were treated with $25{\mu}m$ sandblasting (Group A), stone wheel(Group B), stone wheel and EZ oxisor(Group C), $75{\mu}m$ sandblasting(Group D) and EZ oxisor application after $75{\mu}m$ sandblasting(Group E). They were subdivided into no primer application (Group I), MR bond application(Group II) and Metafast bonding liner (Group III). Then specimens were completed though being bonded with relining resins. The specimens were stored in $38^{\circ}C$ water for 48 hours and tensile strength was measured using the universal testing machine. The results were as follows, 1. Primer application groups showed higher bond strength than no primer application group(p<0.05). 2. In comparison with primer application groups, MR bond group showed higher bond strength than Meta fast bonding liner application group(p<0.05). 3. In comparison with surface treatment methods, Bond strengths of group A and B were significantly different with group C, D, and E, and group C were significantly different with group D, and E in no primer application group()(0.05). In primer application groups, group A, B, C were significantly different with group D and E(p<0.05). According to results of this study, Metal primer application and metal surface roughening were considered to be advantageous for relining of metal base dentures.

• Restorative Dentistry and Endodontics
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• 제26권2호
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• pp.153-161
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• 2001

The purpose of this study was to evaluate microleakage of six current dentin bonding systems. In this in vitro study, class V cavities were prepared on buccal and lingual surfaces of thirty extracted human molars. Each margin was on enamel and dentin/cementum. Experimental teeth were randomly divided into six groups of 5 each. Group 1 : Scotchbond Multi-Purpose; Group 2 : Single Bond; Group 3 : Prime&Bond NT ; Group 4 : Clearfil Liner Bond 2 ; Group 5 : MAC Bond II ; Group 6 : One-up Bond F. The bonding agent and composite resin were applied to class V cavities according to manufacturer's directions. After thermocycling, the specimens were immersed in 0.5% basic fuchsin dye solution for 6 hours and sectioned longitudinally through the center of the restoration with a low speed diamond saw. The degree of microleakage was measured as the extent of dye penetration under the stereomicroscope at $\times$20. The data were analyzed using one way ANOVA. When significant differences found. multiple comparisons were made using Duncan's Multiple Range Test. The results of this study were as follows: 1. In all groups, leakage value seen at the enamel margin was significantly lower than that seen at the dentin margin(P<0.001). 2. At the enamel margin, none of the dentin bonding systems used in this study showed statistically significant difference in leakage values(P<0.05). 3. At the cementum margin, group 3 showed the highest leakage value, and others were decreased as group 5, 6, 4 in that order, and group 1, 2 showed the lowest leakage value. There was statistically significant difference between group 3 and the other groups except for group 5(P<0.05).

• Restorative Dentistry and Endodontics
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• 제21권2호
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• pp.585-601
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• 1996

The purpose of this study was to elucidate the effect of blood-and saliva-contamination during dentin pretreatment procedure on tensile bond strength, and to investigate the effect of contaminant-removing treatments on the recovery of bond strength of dentin bonding agents. Dentin specimens prepared from freshly extracted bovine mandibular anterior teeth were divided into non-contaminated control and contaminated experimental groups. The specimens of the contaminated group were contaminated with saliva or blood after etching or priming procedure, followed by contaminant-removing treatments. All the specimens were bonded with All Bond$^{(R)}$ 2 dentin bonding agent and Bisfil$^{TM}$ composite resin or Scotchbond$^{TM}$ Multipurpose and Z100. After all the bonded specimens were stored in $37^{\circ}C$ distilled water for 24 hours, tensile bond strengths were measured. The contaminated dentin and fractured dentin surfaces were examined under the scanning electron microscope. The results were as follows : Contaminated specimens showed lower bond strength than non-contaminated ones regardless of the kind of contaminant, contamination time and contaminant-removing treatments, except specimens which were acid-etched following saliva contamination after etching in All Bond$^{(R)}$ 2 groups (p<0.05). Blood contaminant resulted in much bond strength decrease than saliva ones (p<0.01), and contamination after priming resulted in much decrease in bond strength than after etching (p<0.01). Re-etching resulted in increase of bond strength in the specimens contaminated with saliva after etching but not in blood contaminated ones. Re-priming resulted in increase of bond strength in the specimens contaminated after priming regardless of the kind of contaminant.

• 한국분말재료학회지
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• 제24권6호
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• pp.489-493
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• 2017

In this study, the surface passivation process for InP-based quantum dots (QDs) is investigated. Surface coating is performed with poly(methylmethacrylate) (PMMA) and thioglycolic acid. The quantum yield (QY) of a PMMA-coated sample slightly increases by approximately 1.3% relative to that of the as-synthesized InP/ZnS QDs. The QYs of the uncoated and PMMA-coated samples drastically decrease after 16 days because of the high defect state density of the InP-based QDs. PMMA does not have a significant effect on the defect passivation. Thioglycolic acid is investigated in this study for the effective surface passivation of InP-based QDs. Surface passivation with thioglycolic acid is more effective than that with the PMMA coating, and the QY increases from 1.7% to 11.3%. ZnS formed on the surface of the InP QDs and S in thioglycolic acid show strong bonding property. Additionally, the QY is further increased up to 21.0% by the photochemical reaction. Electron-hole pairs are formed by light irradiation and lead to strong bonding between the inorganic and thioglycolic acid sulfur. The surface of the InP core QDs, which does not emit light, is passivated by the irradiated light and emits green light after the photochemical reaction.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 II
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• pp.743-746
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• 2003

We have successfully used hydrophobic direct-wafer bonding, along with H-induced layer splitting of Ge, to transfer 700nm think, single-crystal Ge films to Si substrates. Optical and electrical properties have been also observed on these samples. Triple-junction solar cell structures gown on these Ge/Si heterostructure templates show comparable photoluminescence intensity and minority carrier lifetime to a control structure grown on bulk Ge. When heavily doped p$^{+}$Ge/p$^{+}$Si wafer bonded heterostructures were bonded, ohmic interfacial properties with less than 0.3Ω$\textrm{cm}^2$ specific resistance were observed indicating low loss thermal emission and tunneling processes over and through the potential barrier. Current-voltage (I-V) characteristics in p$^{+}$Ge/pSi structures show rectifying properties for room temperature bonded structures. After annealing at 40$0^{\circ}C$, the potential barrier was reduced and the barrier height no longer blocks current flow under bias. From these observations, interfacial atomic bonding structures of hydrophobically wafer bonded Ge/Si heterostructures are suggested.ested.

• 대한전자공학회논문지
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• 제10권3호
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• pp.1-9
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• 1973

파일롯트 램프와 숫자표시를 목적으로 국내에서 처음으로 화합물반도체인 갈륨 인을 사용해서 발광다이오드를 만들었다. 이같이 만든 다이오드는 밝고 선명한 붉은 빛을 냈으며 발광하는데 필요한 순방향 바이아스 전류는 5mA 이하였다. 다이오드의 p-n 접합면은 n형 GaP 단결정 기판에 liquid phase epitaxy방법으로 성장시켰고 이때의 Ga 용액의 온도는 약 1300°K정도를 유지했다. 이렇게 하여 제조된 p-n 접합체에 wire bonding으로 ohmic contact시켜 다이오드를 제조했다. 칼륨인 발광다이오드는 매우 적은 전류로 발광되는 장점과 성장 반웅시 질소를 불순물로 doping시키면 녹색으로 발광되는 장점을 갖고 있으므로 앞으로 양산화의 전망이 매우 밝다.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• 제25권4호
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• pp.224-229
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• 2014

Objectives : This study was conducted in order to investigate the influences of school violence on the mental health of student victims and their parents. Methods : A total of 56 (aged 7-18) student victims and their parents were selected to participate in a survey. The students had experienced school violence from June 2012 to October 2013. They completed a set of self-report questionnaires, including socio-demographic characteristics, family relationship, Impact of Event Scale-Revised, Child Depression Inventory (CDI), Beck Depression Inventory, Revised Children's Manifest Anxiety Scale, and Parental Bonding Instrument to evaluate psychiatric complications and to understand the emotional bonding between them. Results : The student's level of impact of event was significantly related to the parent's level of impact of event (p<.001). The student's high CDI score showed positive correlation with high level of impact of event (p<.001). In addition, higher level of the student's perceived emotional support and understandability of family showed association with lower level of impact of event (p<.01, p<.05). Conclusion : The results of this study suggest that the psychiatric sequelae of school violence is seriously affected by family support and parent's level of impact of event. Therefore, more active intervention is needed for both students and their parents.

• Bulletin of the Korean Chemical Society
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• 제26권1호
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• pp.63-71
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• 2005

Equilibrium geometries, electronic structures, and energies of borocarbon clusters (binary compounds of carbon and boron), an unexplored class of molecules with highly unusual characteristics and potential for further development, have been investigated by means of B3LYP/6-311+G$^*$ density functional theory computations. A large number of B$_7$C${_1}^{1-}$, B$_6C_2$, and B$_5C_{3}\,^{1+}$ clusters with planar and non-planar monocyclic and polycyclic rings, as well as cage structures, have been systematically studied. Unexpectedly, planar forms are predicted not only to be the most stable structures, but also, in many cases, to have unprecedented planar heptacoordinate boron (p-heptaB) and planar heptacoordinate carbon (p-heptaC) arrangements. All these pheptaB and p-heptaC have 6π electrons and are aromatic according to the nucleus independent chemical shift (NICS). This novel bonding pattern is analyzed in terms of natural bond orbital (NBO) analysis. For virtually all possible B$_7$C${_1}^{1-}$, B$_6C_2$, and B$_5C_{3}\,^{1+}$ combinations, the p-heptaB arrangements are the more stable than other type structures.

• Korean Membrane Journal
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• 제10권1호
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• pp.20-25
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• 2008

Proton conducting composite membranes were prepared by solution blending of poly(vinylidene fluoride-co-chlorotrifluoroethylene)-graft-poly(sulfopropyl methacrylate) (P(VDF-CTFE)-g-PSPMA) graft copolymer and heteropolyacid (HPA). The P(VDF-CTFE)-g-PSPMA graft copolymer was synthesized by atom transfer radical polymerization (ATRP) using direct initiation of the secondary chlorines of P(VDF-CTFE). FT-IR spectroscopy revealed that HPA nanoparticles were incorporated into the graft copolymer via hydrogen bonding interactions. The water uptake of membranes continuously decreased with increasing HP A concentration up to 45wt%, after which it slightly increased. It is presumably due to the decrease in number of water absorption sites due to hydrogen bonding interaction between the HP A particles and the polymer matrix. The proton conductivity of membranes increased with increasing HPA concentration up to 45wt%, resulting from both the intrinsic conductivity of HP A particles and the enhanced acidity of the sulfonic acid of the graft copolymer.