• Journal of Advanced Marine Engineering and Technology
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• v.24 no.1
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• pp.49-58
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• 2000

Thermal spraying is one of the most common surface coating techniques to be used for many applications and flame spraying covers a wide range of different materials which can be coated onto various substrates. The purpose of this study is to investigate the effects of mixed ratio in composite coatings on the mechanical and anti-corrosion properties. The five different types of composite coatings were made with $Al_2O_3$ ceramic and Ni-alloy powder on the mild steel substrate by flame spraying method. The mechanical properties such as microhardness, adhesive strength and erosion resistance and corrosion resistance were tested for the sprayed coating specimens. The results obtained are summarized as follows; 1. The composite coating layers greatly improve the microstructure, erosion resistance and adhesive strength by increasing the content of Ni-Al alloy. 2. Microhardness of the compsite coating layer is decreased by increasing the content of Ni-Al alloy. 3. The anti-corrosion properties is considerably improved by increasing the compsite rate of Ni-Al alloy.

• Carbon letters
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• v.13 no.1
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• pp.34-38
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• 2012

Successful application of graphene requires development of various tools for its chemical modification. In this paper, we present a Raman spectroscopic investigation of the effects of UV light on single layer graphene with and without the presence of $O_2$ molecules. The UV emission from a low pressure Hg lamp photolyzes $O_2$ molecules into O atoms, which are known to form epoxy on the basal plane of graphene. The resulting surface epoxy groups were identified by the disorder-related Raman D band. It was also found that adhesive residues present in the graphene samples prepared by micro-mechanical exfoliation using adhesive tape severely interfere with the O atom reaction with graphene. The UV-induced reaction was also successfully applied to chemical vapor deposition-grown graphene. Since the current method can be readily carried out in ambient air only with UV light, it will be useful in modifying the surfaces of graphene and related materials.

• Computers and Concrete
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• v.27 no.3
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• pp.253-268
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• 2021

The present paper treats the free vibration problem of the masonry wall strengthened with thin composite plate by viscoelastic adhesive layer. For this goal two steps are considered in the analytical solution. In the first one, an efficient homogenisation procedure is given to provide the anisotropic properties of the masonry wall. The second one is dedicated to purpose simplified mathematical models related to both in-plane and out-of-plane vibration problems. In these models, the higher order shear theories (HSDT's) are employed for a more rigours description of the shear deformation trough the masonry wall and the composite sheet. Ritz's method is deployed as solution strategy in order to get the natural frequencies and their corresponding loss factors. The obtained results are validated with the finite element method (FEM) and then, a parametric study is undertaken for different kinds of masonry walls strengthened with composite sheets.

• Journal of Dental Rehabilitation and Applied Science
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• v.22 no.2
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• pp.181-191
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• 2006

The objectives of this study were to evaluate the tensile strength of resin-infiltrated demineralized dentin according to the demineralization time, and to evaluate the tensile strength of hybrid layer that is formed by infiltrating different priming adhesives or primer/adhesive into demineralizd dentin matrix. Seventy five hour-glass shaped dentin specimens were prepared in mid-coronal dentin from extracted human molars. Thirty specimens were distributed into three groups according to demineralization time - 2 hours, 4 hours and 8 hours. Each specimen was placed in primer/adhesive of All-Bond 2 for 5 hours of infiltration. Another forty-five specimens of them were demineralized in 37% phosphoric acid for 4 hours. They were randomly assigned to three experimental groups - AB, SB and OS - to designate All-Bond 2, Single Bond and One-Step. Each specimen was placed in one of three different adhesives for 5 hours of infiltration. The specimens were visible light-cured for 5 minutes, and then stored for 24 hours in distilled water at $37^{\circ}C$. After that, microtensile bond strength for each specimen was measured, and the fractured surfaces were then observed by SEM. The data were statistically analysed by one-way ANOVA and Tukey's multiple comparison test and Bonferroni's multiple comparison test. The results were as follows; 1. Tensile strength of the group demineralized for 4 hours was significantly higher than that of groups demineralized for 2 hours and 8 hours (P < .01). 3. Tensile strength of the AB group was significantly higher than that of the SB group and OS group (P < .01).

• Applied Microscopy
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• v.47 no.2
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• pp.70-74
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• 2017

In the case of genus Nothobranchius, Nothobranchiidae, the morphology of fertilized eggs and ultrastructures of fertilized egg envelopes have been reported in only two fishes. Therefore it is hard for sure to these morphological characteristics show genus specificity because of lower research samples. So, we studied the morphology of fertilized egg, and compared the ultrastructures of outer surface, micropyle, and section of fertilized egg envelopes under the light and electron microscopes from the other two species, Nothobranchius foerschi and Nothobranchius rachovii, Nothobranchiidae to find out whether these structures have the species specificity or not. Both fertilized eggs were spherical, demersal and adhesive, and have a large oil droplet. The adhesive whip-like structures were distributed on the outer surface of egg envelope, and a micropyle located on the animal pole. The fertilized egg envelope consisted of two distinct layers: an outer electron-dense layer with adhesive structures and an inner lamellae layer in both species. The external shapes of fertilized egg and ultrastuctures of outer surface, micropyle, and section of fertilized egg envelope have same structure including results before. Our data indicate that these morphological characteristics of fertilized egg and fertilized egg envelope show genus Nothobranchius specificity.

• Journal of the Korean Wood Science and Technology
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• v.26 no.1
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• pp.97-105
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• 1998

This study examined the combined using effects of urea-formaldehyde (UF) resin and emulsifiable methylene diphyenyl diisocyanate (EMDI) resin to overcome performance limit of three-layer particleboards commonly made by UF resin. Two adhesive adding methods were applied with three types of resin combination system to each layer of particleboards. The one was simultaneously spreading method with emulsified compound resin (UF and EMDI) while the other was separately spreading method with unemulsified EMDI resin after UF resin spreading. The performance of particleboards bonded with 2% EMDI resin to the inner layers(IL) were similar to that of controls bonded with 8% UF resin. In the case of the emulsified compound resin application to the all layers of particleboards, there were marked reinforcing effects of EMDI resin, although a small amount of EMDI resin was mixed with UF resin. Especially bending MOR after 24 hours cold water-immersion and thickness swelling after 2 hours hot water-immersion of compound resin-bonded particleboards were remarkably different from those of pure UF resin-bonded particleboards. It was found that separately spreading method with unemulsified EMDI resin was more effective than simultaneously spreading method with emulsified compound resin to sustain the internal bond strength of particleboards after 24 hours cold water-immersion. In the resin combination systems to outer layers/inner layers of particleboards, water resistance and strength properties were superior in order of UF+EMDI/UF+EMDI > UF/UF+EMDI > UF/UF. And water resistance of particleboards was greatly dependent upon EMDI resin level in any adhesive adding method.

• Applied Microscopy
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• v.31 no.1
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• pp.85-90
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• 2001

The ultrastructures of the fertilized egg envelope from long nose barbel, Hemibarbus longirostris belong to Cyprinidae was studied using scanning and transmission electron microscopes. The fertilized egg was adhesive type, have a single micropyle resembling the pathway of sperm in the area of the animal pole. An outer surface of the fertilized egg envelope was arranged by adhesive structures irregularly. In section of fertilized egg, the egg envelope consists of two layers, an outer adhesive twofold layer with mushroom-like cluster and an inner lamellae layer consisting of four layers. These ultrastructural characters of fertilized egg envelope from long nose barbel can be utilized in taxonomy of teleost.

• Journal of the Korea Institute of Building Construction
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• v.16 no.2
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• pp.125-131
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• 2016

According to the increment of urban buildings, the demand of eco-environment space will be also increased. Therefore, the artificial ground green system on a roof will be supplied gradually. In this study, the concept of simplification, unification and prefabrication was widely applied to supply green system. Consequently, the box unit system with a continuous soil layer was developed, and adhesive property, wind resistance and insulation property of this system were evaluated for site application. As a results of adhesive property and wind resistance test, comparing with design wind pressure and wind velocity, this system was safe at the height of 100m building located in urban. In addition, results of temperature measurement for 120 days showed 17% higher insulation property at daytime and 45% higher insulation property at night than normal box unit system owing to continuous soil layer.

• Restorative Dentistry and Endodontics
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• v.21 no.2
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• pp.505-516
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• 1996

The effects of application of dentin desensitizer containing glutaraldehyde (Gluma Desensitizer) and dentin adhesive system (All Bond 2) to the exposed dentin on the intradental nerve activity (INA) and the occluding aspects of dentinal tubules were investigated in cat canine teeth. Single pulp nerve units were dissected from the inferior alveolar nerve and indentified as $A{\delta}$-fiber units. The INAs elicited by 4M NaCl before and after the application of each experimental agent were compared. The morphological changes of exposed dentin surfaces and dentinal tubules in the dentin specimens used to record INAs were observed by SEM. The results obtained were as follows. 1. Eight $A{\delta}$-fiber units (conduction velocity: $8.0{\pm}4.0m$/sec) were identified. 4M NaCl evoked an irregular burst of action potentials which ceased immediately after washing. 2. In 4 $A{\delta}$-fiber units, the change of INA after the application of Gluma Desensitizer was $133.9{\pm}80.7%$ when it was compared with the INA before the application of the same agent. 3. In 4 $A{\delta}$-fiber units, application of All Bond 2 completely abolished the INA induced by 4M NaCl. 4. In specimens applied with Gluma Desensitizer, the formation of hybrid layer as well as the identification of resin penetration and reaction products with proteins in dentinal tubules were not clearly observed in interface between dentin and adhesive resin. In specimens applied with All Bond 2, the gap width of 2-$3{\mu}m$ was formed between exposed dentin and adhesive resin, and the hybrid layer and resin tags were not clearly formed either.

• Tribology and Lubricants
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• v.13 no.1
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• pp.42-52
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• 1997

This paper deals with wear characteristics of ion-nitrided metal theoretically and experimentally in order to analysis of wear phenomena. Wear tests show that compound layer of ion-nitrided metal reduces wear rate when the applied wear load is mall. However, as th load becomes large, the existence of compound layer tends to increase wear rate. The residual stress at the surface of ion-nitrided metal is measured, and the internal stress distribution is calculated when the normal and tangential forces are applied to the surface of metal. Compressive residual stress is largeest at the compound layer, and decreases as the depth from the surface increases. Calculation shows that the maximum stress exists at a certain depth from the surface when normal and tangential force are applied, and that the larger the wear load is the deeper the location of maximum stress becomes. In the analysis, it is found that under small applied wear load the critical depth, where voids and cracks may be created and propagated, is located at the compound layer, as the adhesive wear, where hardness is an important factor, is created the existence of compound layer reduces the amount of wear. When the load becomes large the critical depth is located below the compound layer, and delamination, which may be explained by surface deformation, crack nucleation and propagation, is created, and the existence of compound layer increases wear rate.