• Composites Research
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• 제17권6호
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• pp.14-21
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• 2004

본 연구에서는 몇 가지 접합 방법에 따라 일방향 복합재료 단일 겹치기 접합 조인트의 파손 과정, 모드 및 강도를 실험적으로 평가하였다 접합 방법으로는 접착제 없는 동시성형, 접착제를 사용한 동시성형 및 이차 접합의 세 가지를 고려하였다 또한 이차 접합 조인트에서 몇 가지 파라미터의 영향도 살펴보았다. 접착제 없는 동시성형 시편은 가장 우수한 조인트 강도를 나타내었다. 이차접합 조인트에서는 접착제 층의 점진적인 파손이 발생하였다. 접착제의 재료 및 접합 강도가 상대적으로 강한 필름 접착제의 동시성형 조인트는 갑작스런 층간분리 파손이 발생하였으며 이차 접합 조인트보다 더 낮은 파손 강도를 나타내었다. 이차 집합 조인트에서 층간분리 파손이 발생하지 않은 것은 접착제 층에서의 균열 진전 및 점진적 파손이 층간분리 파손을 방지한 것으로 보인다. 따라서 복합재료 접합 조인트의 파손 강도는 접착제의 재료 강도 또는 접착 성능과 항상 비례하지 않으며 이것은 복합재료가 층간 분리 파손에 약하기 때문이다.

• The Journal of Advanced Prosthodontics
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• 제3권3호
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• pp.119-125
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• 2011

PURPOSE. The aim of this study was to evaluate the influence of resin cement thickness on the microtensile bond strength between zirconium-oxide ceramic and resin cement. MATERIALS AND METHODS. Thirty-two freshly extracted molars were transversely sectioned at the deep dentin level and bonded to air-abraded zirconium oxide ceramic disks. The specimens were divided into 8 groups based on the experimental conditions (cement type: Rely X UniCem or Panavia F 2.0, cement thickness: 40 or 160 ${\mu}m$, storage: thermocycled or not). They were cut into microbeams and stored in $37^{\circ}C$ distilled water for 24 h. Microbeams of non-thermocycled specimens were submitted to a microtensile test, whereas those of thermocycled groups were thermally cycled for 18,000 times immediately before the microtensile test. Three-way ANOVA and Sheffe's post hoc tests were used for statistical analysis (${\alpha}$=95%). RESULTS. All failures occurred at the resin-zirconia interface. Thermocycled groups showed lower microtensile bond strength than non-thermocycled groups (P<.001). Differences in cement thickness did not influence the resin-zirconia microtensile bond strength given the same resin cement or storage conditions (P>.05). The number of adhesive failures increased after thermocycling in all experimental conditions. No cohesive failure was observed in any experimental group. CONCLUSION. When resin cements of adhesive monomers are applied over air-abraded zirconia restorations, the degree of fit does not influence the resin-zirconia microtensile bond strength.

• Applied Microscopy
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• 제52권
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• pp.6.1-6.5
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• 2022

We examined the morphology of the fertilized egg and the fine structure of fertilized egg envelopes of Poropanchax normani belonging to the family Poeciliidae, also known as Norman's lampeye using light and electron microscopes. The fertilized eggs with narrow perivitelline space were found to be spherical and demersal, additionally containing small oil droplets in the vitelline membrane. Further, a bundle of adhesive filaments was observed to be present on one side of the fertilized egg. These filaments possessed remarkably high elasticity and were approximately 1-3mm in length. The size of the fertilized egg was determined to be about 1.49 ± 0.07mm (n=30). The outer surface appeared smooth, and adhesive filaments originating at different location of the surface of the envelope were found to be distributed around the egg envelope and were joined together to form a single long bundle in scanning electron microscopic observation. A peak-like structure formed of several straight wrinkles was observed around the micropyle. However, the complete structure of the micropyle could not be studied due to the depth at which it was located. Additionally, the total thickness of the egg envelope was ascertained to be approximately12.5-14.5㎛. The egg envelope consisted of two distinct layers, an outer electron dense layer and an inner lamellar layer, further consisting of 10 sublayers of varying thicknesses. Collectively, it was observed that the morphological characteristics of the fertilized egg, fine structures surrounding the micropyle, outer surface, adhesive structure consisting adhesive filaments, and sections of fertilized egg envelope displayed species specificity.

• Restorative Dentistry and Endodontics
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• 제24권4호
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• pp.546-553
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• 1999

In Older to evaluate the effectiveness of 'One-bottle dentin adhesive system', the shear bond strengths of two fourth generation dentin adhesive systems and two One-bottle systems to the occlusal dentin of the freshly extracted third molars were measured by the regulation of the ISO TR 11405. The fourth generation dentin adhesive systems used in this study were Scotchbond Multi-Purpose Plus and All-Bond 2, and the One-bottle systems were Single Bond and One-Step. The effects of the thickness of hybrid layer and adhesive layer, the diameter of resin tag and the ratio between the diameter of resin tag and that of dentinal tubule were analyzed as the contributing factors of the shear bond strength of dentin bonding systems from the Scanning Electron Microscopic images. The results were as follows: 1. The shear bond strengths of Scotchbond Multi-Purpose, All-Bond 2, and Single Bond were 16.98${\pm}$3.40 MPa, 15.10${\pm}$2.77 MPa and 15.05${\pm}$3.18 MPa, respectively. There were no statistical differences(p>0.05). 2. But, the shear bond strength of One-Step were significantly lower than those of the other groups (11.81${\pm}$1.95 MPa, p<0.05). 3. The thicknesses of hybrid layer and adhesive layer of One-Step were significantly thinner than those of the other groups(p<0.05). The differences of the diameter of resin tag(p=0.0685) and the ratio between the diameter of resin tag and that of dentinal tubule(p=0.2401) were not significant among all the material groups. 4. The thickness of hybrid layer and adhesive layer might be considered as contributing factors of the she at bond strengths of dentin bonding systems, but the diameter of resin tag and the ratio between the diameter of resin tag and that of dentinal tubule might not.

• Clinics in Shoulder and Elbow
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• 제21권3호
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• pp.127-133
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• 2018

Background: This study was undertaken to evaluate the outcome of the arthroscopic capsular release for adhesive capsulitis of the shoulder. Methods: This study retrospectively investigated thirty shoulders in 29 patients who presented with recalcitrant adhesive capsulitis and underwent arthroscopic treatments. Other than typical findings of adhesive capsulitis, combined pathologies in the glenohumeral joint and subacromial space were evaluated by arthroscopy. Clinical evaluations were performed using the Constant's score and ranges of motion (ROM) at preoperative, 6 months postoperatively and at the final follow-up. Results: Our study included 17 women and 12 men with a mean age of 53.8 years (range, 34-74). Mean follow-up duration was 24 months (range, 12-40 months). Assessment of combined pathologies revealed that partial rotator cuff tear of less than 25% thickness, was most common (overall 83.3%; with bursal 57% and articular 23%). Subacromial synovitis and adhesion were also frequent (53.3%). The Constant score and ranges of motion significantly improved at the final follow-up, compared with preoperative levels. However, clinical results at 6 months postoperatively were found to be significantly inferior to those observed at the final follow-up ($p{\leq}0.001$ for all factors). Functional impairment was the major complaint in 59.3% patients at the 6 months follow-up. Conclusions: Although arthroscopic capsular release yielded favorable outcome at the mean 24 months follow-up, pain and motion limitations at 6-month postoperatively persisted in more than 50% of our patients. While combined pathologies were commonly encountered during arthroscopy, although their effects on surgical outcome in adhesive capsulitis remains unclear in this study.

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2002년도 추계학술대회
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• pp.710-710
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• 2002

No Abstract, See Full Text

• 대한소아치과학회지
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• 제44권2호
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• pp.180-187
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• 2017

본 연구는 접착층을 통한 자이오머(Beautifil Injectable)와 컴포머($Dyract^{(R)}$ XP)의 불소 유리를 직접적으로 평가하고 비교하였다. 자이오머와 컴포머 그리고 불소를 함유하지 않은 복합레진의 원통형 시편을 각각 20개씩 제작하였다. 20개 중 10개의 시편은 접착제(Scotchbond Multi-Purpose)를 균일하게 도포하였다. 각 시편은 2 mL 탈이온수에 넣어 $37^{\circ}C$에서 보관하였으며 1, 3, 7, 14, 21, 28일째 유리된 불소를 측정하였다. 접착제를 적용한 추가적인 시편을 제작하여 주사전자현미경으로 접착제가 균일하게 도포되었는지 확인하였다. 자이오머와 컴포머에 접착제를 도포한 군은 3일째까지 불소가 검출되지 않았으나 7일째부터는 불소가 검출되었다. 접착제는 불소의 유리를 완전히 차단하지 못하였으며, 접착제를 투과하는 자이오머와 컴포머의 불소 유리량은 유의하게 감소하였다(p < 0.05). 불소의 유리량 감소는 컴포머보다 자이오머에서 더 현저했다.

• 센서학회지
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• 제16권5호
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• pp.325-330
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• 2007

For the application to optic devices, wafer level package including spacer with particular thickness according to optical design could be required. In these cases, the uniformity of spacer thickness is important for bonding strength and optical performance. Packaging process has to be performed at low temperature in order to prevent damage to devices fabricated before packaging. And if photosensitive material is used as spacer layer, size and shape of pattern and thickness of spacer can be easily controlled. This paper presents polymer bonding using thick, uniform and patterned spacing layer of SU-8 2100 photoresist for wafer level package. SU-8, negative photoresist, can be coated uniformly by spin coater and it is cured at $95^{\circ}C$ and bonded well near the temperature. It can be bonded to silicon well, patterned with high aspect ratio and easy to form thick layer due to its high viscosity. It is also mechanically strong, chemically resistive and thermally stable. But adhesion of SU-8 to glass is poor, and in the case of forming thick layer, SU-8 layer leans from the perpendicular due to imbalance to gravity. To solve leaning problem, the wafer rotating system was introduced. Imbalance to gravity of thick layer was cancelled out through rotating wafer during curing time. And depositing additional layer of gold onto glass could improve adhesion strength of SU-8 to glass. Conclusively, we established the coating condition for forming patterned SU-8 layer with $400{\mu}m$ of thickness and 3.25 % of uniformity through single coating. Also we improved tensile strength from hundreds kPa to maximum 9.43 MPa through depositing gold layer onto glass substrate.

• 소음진동
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• 제8권6호
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• pp.1093-1102
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• 1998

The success of controllability of smart structures depends on the quality of the bonding along the interface between the main structure and the attached sensing and acuating elements. Generally, the analysis procedures neglect the effect of the interfacial bond layer or assume that this bond layer behaves like viscoelastic material. Three different bond layers. two modified epoxy adhesives, and one isocyanate adhesive were prepared for their toughness and moduli. Bond layer of the chosen adhesive provides an almost perfect bonding condition between the composite structure and the PZT while bended significantly like arrow-shape. The perfect bonding condition is tested by considering various material properties of the bond layers. and based on this perfect bonding condition, the effects of the interfacial bond layer on the dynamic behavior and controllability of the test structure is experimentally studied. Once the perfect bonding condition is achieved. dynamic effects of the bond layer itself on the dynamic characteristics of the main structure is negligible. but the contribution of the attached PZT elements on the stiffness of the multi-layered structure becomes significant when the thickness of the bond layer increased.

• 비파괴검사학회지
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• 제30권3호
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• pp.236-243
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• 2010

Fiber Bragg grating(FBG) sensor arrays can be used to monitor the mechanical behavior of the large composite structures such as wind turbine rotor blades and aircrafts. However, brittle FBG sensors, especially multiplexed FBG sensors are easily damaged when they are installed in the flexible structures. As a protection of brittle FBG sensors, epoxy packaged FBG sensors have been presented in this paper. Finite element analysis and experiments were performed to evaluate the effects of adhesives, packaging materials and the bonding layer thickness on the strain transmission. Two types of epoxy were used for packaging FBG sensors and the sensor probes were attached with various bonding layer thickness. It was observed that thin bonding layer with high elastic modulus ratio of the adhesive to packaging provided good strain transmission. However, the strain transmission was significantly decreased when elastic modulus of the adhesive was much lower than the packaged FBG sensor probe's one.