• Proceedings of the KAIS Fall Conference
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• 2011.12b
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• pp.584-586
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• 2011

본 논문에서는 도로 건설현장에서 발생하는 임목폐기물을 도로 보호길 어깨 포설에 재활용 하는 친환경 방안을 제시하였다. 기존에는 임목폐기물을 폐기물로 분류하여 폐기물 전문업체를 통해 위탁 처리하였으나, 임목폐기물의 효율적인 자원 낭비를 방지하고자 도로 보호길 어깨에 임목폐기물을 파쇄하여 포설하고자 한다. 포설 방법은 보호길 어깨를 굴착하여 파쇄칩을 포설 및 다짐한 후 친환경성 접착제를 살포한다. 위 활용 방안의 가능성을 입증하기 위해 우수 침식시험기를 자체 제작 후 실내시험을 실시하였다. 침식 시험기를 이용한 시험 결과 현장 적용이 가능하다는 결론을 얻었다.

• Journal of the Korea Institute of Building Construction
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• v.24 no.3
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• pp.331-341
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• 2024

In this study, the flexural strength and ductility of steel-timber composite beams were evaluated to enhance the structural performance of glued-laminated timber beams. Three specimens were fabricated, including one reference glulam beam and two composite beams. The composite beams were constructed by attaching steel sections to the glulam beam using either liquid adhesive or screws. The experimental results showed that the structural performance of the steel-timber composite beams was approximately 2-3 times higher than the reference glulam beam, indicating that both flexural strength and ductility were sufficiently ensured. Notably, the specimen constructed with liquid adhesive demonstrated superior structural performance compared to the screw-attached specimen.

• Restorative Dentistry and Endodontics
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• v.32 no.3
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• pp.208-221
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• 2007

The fracture toughness test is believed as a clinically relevant method for assessing the fracture resistance of the dentinal restoratives. The objectives of this study were to measure the fracture toughness $(K_{1C})$ and microtensile bond strength of dentin-resin composite interface and compare their relationship for their use in evaluation of the integrity of the dentin-resin bond. A minimum of six short-rod specimens for fracture toughness test and fifteen specimens for microtensile bond strength test was fabricated for each group of materials used. After all specimens storing for 24 hours in distilled water at $37^{\circ}C$, they were tensile-loaded with an EZ tester universal testing machin. Statistical analysis was performed using ANOVA and Tukey's test at the 95% confidence level, Pearson's coefficient was used to verify the correlation between the mean of fracture toughness and microtensile bond strength. FE-SEM was employed on fractured surface to describe the crack propagation. Fracture toughness value of Clearfil SE Bond (SE) was the highest, followed by Adper Single Bond 2 (SB), OptiBond Solo (OB), ONE-STEP PLUS (0S), ScotchBond Multi-purpose (SM) and there was significant difference between SE and other 4 groups (p < 0.05). There were, however, no significant difference among SB, OB, OS, SM (p > 0.05). Microtensile bond strength of SE was the highest, followed by SB, OB, SM, OS and OS only showed significant lower value (p < 0.05). There was no correlation between fracture toughness and microtensile bond strength values. FE-SEM examination revealed that dentin bonding agent showed different film thickness and different failure pattern according to the film thickness. From the limited results of this study, it was noted that there was statistically no correlation between K1C and ${\mu}TBS$. We can conclude that for obtaining the reliability of bond strength test of dentin bonding agent, we must pay more attention to the test procedure and its profound scrutiny.

• Journal of Korean Society of Steel Construction
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• v.17 no.3 s.76
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• pp.337-346
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• 2005

A composite bridge deck system assembled from a modular profile with double-rectangular cell has been developed for highway bridges. This study is focused on the experimental characterization of flexure performance of pultruded GFRP deck under static loading. Several tests were conducted on single modules and adhesively bonded 2 and 5-modules. The specimen details such as dimensions, material properties and fiber architecture, and experimental set-up and testing procedure have been addressed. It is found that the presented GFRP composite modular deck is very efficient for use in bridges.

• Restorative Dentistry and Endodontics
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• v.36 no.1
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• pp.50-58
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• 2011

Objectives: The purpose of this study was to compare the microshear bond strength (uSBS) of two totaletch and four self-etch adhesive systems and a flowable resin to enamel. Materials and Methods: Enamels of sixty human molars were used. They were divided into one of six equal groups (n = 10) by adhesives used; OS group (One-Step Plus), SB group (Single Bond), CE group (Clearfil SE Bond), TY group (Tyrian SPE/One-Step Plus), AP group (Adper Prompt L-Pop) and GB group (G-Bond). After enamel surfaces were treated with six adhesive systems, a flowable composite resin (Filek Z 350) was bonded to enamel surface using Tygon tubes. the bonded specimens were subjected to uSBS testing and the failure modes of each group were observed under FE-SEM. Results: 1. The uSBS of SB group was statistically higher than that of all other groups, and the uSBS of OS, SE and AP group was statistically higher than that of TY and GB group (p < 0.05). 2. The uSBS for TY group was statistically higher than that for GB group (p < 0.05). 3. Adhesive failures in TY and GB group and mixed failures in SB group and SE group were often analysed. One cohesive failure was observed in OS, SB, SE and AP group, respectively. Conclusions: Although adhesives using the same step were applied the enamel surface, the uSBS of a flowable resin to enamel was different.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.4
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• pp.1-8
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• 2008

RC beam of existing structures often encounter shear problems for various reasons. The shear failure of RC beam is sudden and brittle. Strengthening technique jacketing with external bonding of steel plates(or CFRP and CFS) with epoxy is many use to in practice. This study presents test results on strengthening shear deficient RC beams by external bonding of slit type steel plates. Test parameters are width, interval, length, thickness and angle of slit in steel plates. The purpose was to evaluate the reinforcing effects, failure modes and shear capacities for RC beams of strengthened with various slit type steel plates. The test result confirmed that all slit steel plates improved the stiffness and strength of the specimens significantly. Failure modes of SV series and SD series showed shear fractures and flexure fractures at ultimate state respectively. SD series were ductile rather than SV series.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.4
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• pp.419-426
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• 2017

Attachment of the orthodontic bracket conducted during the window opening procedure can result in failure due to various adverse conditions such as blood or saliva contamination, or other wet conditions. For the success of the bracket attachment, reduction of total operation time is crucial. The purpose of this literature is to evaluate the differences between the final resultant shear bond strength of the conventional method of using phosphoric acid and self-etching primer, and that of the operation time-reduced method in which the curing step is omitted subsequent to the primer application. A total of 40 human maxillary incisors were prepared. Group I(control group) and II were etched with 37% phosphoric acid and Group III and IV were conditioned with self-etching primer. Attachment of the group I and III was conducted by manufacturer's instructions. The operation time of Group II and IV was reduced by eliminating the curing step after the primer application. The resultant shear bond strength of each group was measured and an adhesive remnant index (ARI) was recorded. The mean shear bond strength of group I, II, III, and IV were 14.16 MPa, 8.33 MPa, 8.29 MPa, and 6.48 MPa respectively. Significant differences could only be found between the control group and the experimental groups (p < 0.05). The ARI indicated no significant difference among all groups.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.2
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• pp.232-239
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• 2009

Statements of the problem: Many denture wearers occasionally use denture adhesives to improve denture retention, stability and chewing efficiency. An ideal denture adhesive is nontoxic, non-irritating, and provides comfort to the oral mucosa. Purpose: The purpose of this study was to evaluate the cytotoxicity and adhesive properties of a selected denture adhesive. Material and methods: To test cytotoxicity of the selected denture adhesive, mouse fibroblast cells were used in MTT testing. Cytotoxicity was examined according to the concentration of the denture adhesive and incubated for 1 to 4 days. To examine adhesive property, a denture base was fabricated on an edentulous dentiform. The adhesive was applied to the denture base, then tensile bond strength was measured, to evaluate the change in retention during 3 days. Results and Conclusion: 1. 1% and 2% concentration denture adhesive cream had no cytotoxicity. 2. The tensile bond strength of the group with both denture adhesive and artificial saliva was significantly higher than that of the group with only denture adhesive(P<.05). The tensile bond strength of the group with denture adhesive was significantly higher than that of with only artificial saliva(P<.05). 3. The tensile bond strength had no significant change during 1 hour, and then gradually decreased. After 1 day, it decrease to half. Within the limitation of this study, the tested denture adhesive had no cytotoxicilty and was effective in improving denture retention. The adhesive strength began to continuously decrease after 1 hour and it decreased to half at 1 day after application.

• Restorative Dentistry and Endodontics
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• v.25 no.4
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• pp.543-549
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• 2000

Gutta-percha와 근관sealer를 사용한 근관 충전은 가장 많이 이용되고 성공률이 높은 방법이지만, 현재 사용되는 모든 근관sealer는 미세누출을 나타낸다. 따라서 더 효과적인 근관 폐쇄를 이루기 위한 재료 및 방법들이 연구되어왔다. 이중 상아질 접착제는 근관 충전재와 함께 사용되어 미세누출을 감소시키지만, 근관 내에 사용하기에 술식이 복잡하고 기술이 요구된다. 본 연구의 목적은 gutta-percha와 레진계 근관 sealer로 충전한 근관에서 self-etching primer를 미리 도포한 경우와 도포하지 않은 경우의 치근단 미세누출을 비교하고, self-etching primer를 도포함에 있어 근관 내에 적용하는 방법에 따른 미세누출을 비교하는 것이다. 또한 근관sealer와 상아질 계면을 주사전자현미경으로 관찰하여, 이 결과를 미세누출과 관련시켜보고자 하였다. 36개의 발거된 사람의 단근치에서 치관부를 절단, 제거하고 ProFile로 근관 형성한 후, 무작위로 선택하여 4개의 군으로 분류하였다. 1군에서는 주사기와 30게이지 주사 바늘로 self-etching primer를 근관 내에 적용하였고, 2군에서는 self-etching primer를 paper point에 적셔 근관 내에 적용하였다. 3군에서는 self-etching primer를 적용하지 않았다. 1, 2, 3군의 치아를 gutta-percha와 AH26 sealer를 사용하여 continuous wave 충전법으로 충전한 후 치근단공 주위 3mm를 제외한 치근변에 nail polish를 2회 도포하였고, 4군(음성 대조군)은 치근면 전체에 도포하였다. 1군과 2군에서 각각 2개의 치아는 주사전자현미경적 관찰을 위해 준비하였다. 모든 치아를 Methylene Blue 수용액에 48시간동안 침적, 수세한 후 치아 장축에 평행하게 양분하여 10배의 실물확대현미경 하에서 치근단 색소 침투를 관찰하였다. Self-etching primer를 도포한 군과 도포하지 않은 군 사이에는 평균 미세누출량에 유의한 차이가 없었다. 주사 바늘로 적용한 군과 paper point로 적용한 군 사이에도 평균 미세누출량에 유의한 차이가 없었다. 상아질과 근관 sealer계면의 주사전자현미경 관찰 결과 일부분에서 긴밀한 접착 관계를 나타내었고, 다른 부분에서는 간극을 나타내었다.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.3
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• pp.1-6
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• 2014

The demand for fine-pitch devices is increasing due to an increase in I/O pin count, a reduction in power consumption, and a miniaturization of chip and package. In addition non-scalability of Cu pillar/Sn cap or Pb-free solder structure for fine-pitch interconnection leads to the development of bumpless interconnection system. Few bumpless interconnect systems such as BBUL technology, SAB technology, SAM technology, Cu-toCu thermocompression technology, and WOW's bumpless technology using an adhesive have been reviewed in this paper: The key requirements for Cu bumpless technology are the planarization, contamination-free surface, and surface activation.