• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.567-572
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• 2013

In houses that use heating and cooling system, most of heat loss occurs through the windows, so that low-E glass, double-layered glass, and vacuum glazing are used to minimize the heat loss. In this paper, an encapsulating process that is a final process in manufacturing the vacuum glazing has been studied, and bonding in a vacuum chamber rather than atmospheric bonding was considered. For the efficiency of the encapsulating process, frit-melting temperature and bonding time were optimized with heater temperature, and the glass preheating temperature was optimized to prevent glass breakage due to thermal stress. Thus the vacuum glass was successfully manufactured based on these results and heat transmission coefficient measured was about $5.7W/m^2K$ which indicates that the internal pressure of the vacuum glazing is $10^{-2}$ torr.

• Journal of the Korean Wood Science and Technology
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• v.13 no.3
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• pp.3-26
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• 1985

The object of this study was to investigate the effects on physical and mechanical properties of wood particle and sawdust board combined with wire net. Conventional forming, press-lam, and veneer comply boards combining one to four wire net sheets were made from wood particle and sawdust with different spacings (8, 10, 12, and 18 Mok) and different wire diameters (0.35, 0.50, and 0.80mm) composing wire net. They were compared and analyzed statistically with specific gravity, thickness swelling, length swelling, bending properties (modulus of rupture, modulus of elasticity, work to proportional limit, and total work), internal bonding strength, and screw holding strength between wood particle and sawdust boards. The results obtained at this study as cording to the discussions might be concluded as follows; 1. In specific gravity, both particle and sawdust boards by press-lam method were higher than by conventional forming and veneer comply method, and the boards containing more wire net sheets also showed higher value. But the wire net spacings(Mok) had no influence on specific gravity. In general, particle board showed higher specific gravity than sawdust board. Veneer comply board showed lowest specific gravity values. 2. Both particle and sawdust boards by press-lam method was slightly lower than by conventional forming and veneer comply method in thickness swelling. The sawdust board containing 8, 12. and 18 Mok wire net showed lower thickness swelling than the corresponding particle board, but both sawdust and particle boards containing the T8 and 10 Mok wire net showed higher and similar thickness swelling. 3. Both particle and sawdust boards containing wire net showed no difference in MOR and MOE of bending. Comply board was the highest and particle board showed slightly higher than sawdust board in MOR and MOE values. 4. In work to proportional limit and total work in bending, both particle and sawdust boards containing thicker wire diameter and more wire net sheets showed higher value. From these facts, it is conceivable that boards with thicker wire diameter and more wire net sheets show increasing resistance against external force. But there was no significant difference between particle and sawdust borads. 5. In resistance against delamination (internal bonding strength), both sawdust and particle boards containing wire net showed lower value than control, and also showed decreasing tendency with more number of wire net sheet composed. Particle board showed higher resistance against delamination than sawdust board. 6. In screw holding strength, sawdust board containing thicker wire diameter and more wire net sheets showed higher value, but particle board by press-lam method was higher than by conventional forming and veneer comply method. Screw holding strength of particle board was higher than that of sawdust board.

• Restorative Dentistry and Endodontics
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• v.23 no.2
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• pp.701-709
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• 1998

Many dental composites are Bis-GMA based resin which diluted with the more fluid monomer triethylenglycol dimethacrylate(TEGDMA). TEGDMA is often present in exess so that some quantity remains unreacted following photo-initiated polymerization. TEGDMA is a component of some resin composites which contributes to their cytotoxicity. The presence of dentin between resin composite and pulp space reduce the cytotoxicity in vitro. The root system from extrcted human third molar was removed and then a circular occlusal cavity 4mm in diameter was prepared, leaving a remaining dentinal thickness to the roof of the pulpal chamber within the range 1.0-1.5mm. Dentine was treated with 37% phosphoric acid prior to Z 100 placement without using bonding resin(group 1). In group 2, SMP(Scotchbond Multi Purpose) primer, bonding resin prior to Z 100 placement were applied sequently. In group 3, moulds with internal dimensions 4mm diameter by 2mm depth were used to contain the composite alone with an equvalent mass on tooth model, and then they were immersed directly into water. The purpose of this study is to evaluate the release rate and quantity of TEGDMA with or without the application of bonding resin. Both release rate and total cumulative amount of TEGDMA for the three groups were determined using reversed-phase HPLC at times up to 10 days. The results were as follows: 1. All experimental groups showed the highest rate of release was in the first sample period(0-4.32 min) and the rate of release declined exponentially thereafter. 2. The maximum release rate and total cumulative account of TEGDMA in the tooth model of group 1 and group 2 with the use of SMP bonding resin were reduced however ther were no significant differences between these groups(P>0.05). 3. In the first sample period(0-4.32 min), the rate of release of TEGDMA from composite resin in group 3 immersed directly into water was significantly higher than that in group 1 and group 2 of tooth model(P<0.05). Conclusively, TEGDMA diffusion from Z 100 resin was not effectively prevented by the presence of dentin in spite of using the SMP bonding resin.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.12
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• pp.1097-1102
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• 2003

In this paper, we used only PR as etching mask, while it used usually Cr/AU as etching mask, and in order to fabricate a photosensor has the increased sensitivity, we investigated on the sensitivity of general type and p-i-n type diode. we designed microchannel size width max 10um, min 5um depth max 10um, reservoir size max 100um, min 2mm. Fabrication of microfluidic devices in glass substrate by glass wet etching methods and glass to glass fusion bonding. The p-i-n diode has higher sensitivity than photodiode, Considering these results, we fabricated p-i-n diodes on the high resistive(4㏀$.$cm) wafer into rectangle and finger pattern and compared internal resistance of each pattern. The internal resistance of pin diode can be decreased by the application of finger pattern has parallel resistance structure from 571Ω to 393Ω.

• Journal of the Korea Furniture Society
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• v.11 no.2
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• pp.45-53
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• 2000

This study was carried out to determine the suitability of 3 months old bamboo species of Phyllostachys bambusoides S. et Z., Phyllostachys Pubescens Mazel and Phyllostachys nigra var henonis Stapf as raw materials for the manufacture of strandboard. Total of 108 strandboards were made using urea-formaldehyde resin content level of 12% and one percent of liquid wax emulsion. The strandboard consisted of three layers the top and the bottom layer of which were oriented to the same direction and weighted 25% of the strandboard each. The middle core layer weighed 50% of the board and was perpendicular to the outer top and bottom layers. Analysis was performed to determine the effect of strand lengths and Uowing years of 3 months, 2 years and 3 years on strandboard properties. The physical and mechanical properties of bamboo species and boards were measured and compared to the standard requirements of strandboards. The results are as follows; 1. The more the growing years the higher the density of bamboo. Top part of bamboo indicated higher density value than that of bottom part. 2. Bamboo showed higher static bending strength compared to the main wood species. Longer growing years of bamboo generally inclosed the static tending strength out there were no statistical significancies for Phyllostachys bmbusoides S. et Z. and Phyllostachys pubescens Mazel. 3. Strand length indicated no difference on density and moisture content of strandboard. 5 cm of strand length gave the best static bending strength and internal bonding strength. Bamboo strandboard exhibited lesser extents of thickness swelling than that of CSA standard. 4. 3 months old bamboo gave higher static bending strength of strandboard than those of 2 years and 3 years old bamboo. In case of Phyllostachys nigra var henonis Stapf, 3 months old bamboo indicated higher internal bonding strength than those of 2 years and 3years old bamboo. but in Phyllostachys bambusoides S. et Z., Phyllostachys pubescens Mazel, there were no difference among growing years. Growing years showed no different physical properties of bamboo strandboard.

• Journal of the Korean Wood Science and Technology
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• v.51 no.4
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• pp.253-269
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• 2023

Oriented strand board (OSB) distributed in Korea was collected, and its mechanical properties were investigated according to the International Organization for Standardization (ISO), Japanese Industrial Standards, and Korean Design Standard. Ten types of OSBs were collected, including six types for walls and others for floors. The thickness swelling, moisture content, and density of each product satisfied the ISO standards. All products showed lower formaldehyde emission values than those of the SE0 grade. The internal bonding strengths of all products, except products B, H, and I, met the ISO standards. However, products A, B, C, F, and H did not satisfy the thickness swelling standard of the load-bearing OSB for use in dry conditions. Products D and G showed heavy duty load-bearing OSB for use in humid conditions in terms of internal bonding and bending strength after boiling. In the nail head pull-through force and lateral nail resistance tests, all products met the standards. In terms of the structural bending performance (four points), the six types of OSBs for walls satisfied the standard for bending strength and modulus of elasticity. All the products for flooring met the standard for bending strength but, except for product G, the products did not meet the standard for modulus of elasticity. Although the results of this study cannot represent the performance of all imported OSBs, considering the above results, the water resistance performance of seven types of OSB products did not meet the standard, and 10 types of products did not match the labeling grades.

• Structural Engineering and Mechanics
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• v.64 no.4
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• pp.427-436
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• 2017

Concrete technologists have used ultrasonic pulse velocity test for decades to evaluate the properties of concrete. However, the presented research work focuses on the use of ultrasonic pulse velocity test to study the degradation in steel-concrete bond subjected to increasing loading. A detailed experimental investigation was conducted by testing five identical beam specimens under increasing loading. The loading was increased from zero till failure in equal increments. From the experimentation, it was found that as the reinforced concrete beams were stressed from control unloaded condition till complete failure, the propagating ultrasonic wave velocity reduced. This reduction in wave velocity is attributed to the initiation, development, and propagation of internal cracking in the concrete surrounding the steel reinforcement. Using both direct and semidirect methods of testing, results of reduction in wave velocity with evidence of internal cracking at steel-concrete interface are presented. From the presented results and discussion, it can be concluded that the UPV test method can be successfully employed to identify zones of poor bonding along the length of reinforced concrete beam. The information gathered by such testing can be used by engineers for localizing repairs thereby leading to saving of time, labor and cost of repairs. Furthermore, the implementation strategy along with real-world challenges associated with the application of the proposed technique and area of future development have also been presented.

• Journal of the Korean Society of Safety
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• v.27 no.2
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• pp.78-83
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• 2012

This is a study to confirm how to improve and substitute the existing re-bar with other material such as a fiber rope, especially super fiber rope having much more strong tensile strength. 6(b) different fiber rope reinforced beam with a section of $20{\times}30cm$ have been made and tasted as variables designed in the study. The larger diameter of fiber rope, the more capacity of the beam, even though fiber reinforced beam are increased with ten(10)percent, each. Lower capacity of fiber-reinforced beam than normal RC beam has been analyzed theoretically and empirically, based on a lot of experiences of the same size beam test. Fiber rope-reinforced concrete beam does not have sufficient capacity than RC beam due to insufficient bonding capacity of fiber rope in concrete. It leads to decrease beam bearing capacity and crack around lower center of the beam. Therefore, bonding reinforcement of fiber rope beam such as pinning a triangles steel pin in each knot of fiber rope contributes to improving bearing capacity of fiber rope reinforcing beam.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.1
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• pp.59-66
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• 2013

Fillers have been used for printing paper to improve printability, sheet formation and optical properties and to reduce production costs by replacing expensive wood pulps. However, an increased filler content will decrease paper strength because filler particles interfere with fiber-fiber bonding. In order to increase filler content without sacrificing too much paper strength in high filler content papers, the surface of precipitated calcium carbonate (PCC) has been modified by adsorbing anionic polyacrylamide and cationic starch in series. The adsorbed polymer layers would enhance interactions between the filler surface and the fiber surface, improving internal bonding. It was found that the modified PCC increased paper strength at a given filler content compared to the coventional method. Negligible differences in optical properties and formation of paper, filler and fines retention and drainage on the wire section were observed between the modified and the conventional PCC. However, the decreased bulk of paper was observed when the modified PCC was used.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.30 no.1
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• pp.7-17
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• 1998

With the advent of CLSM in the end of 1980s, it has been applied to the field of pulp and paper science in various ways. This study showed the potentials of CLSM In analyzing a change of pulp fiber and paper properties before and after mechanical treatment. In particular, a quantification of internal fibrillation has been done using cross-sectional images of fibers and image analysis technique, then evaluated the effects of fiber wall delamination on fiber and paper properties. It showed that the delaminated fibers were closely associated to development of the interfiber bonding in a fiber network. The CLSM made it possible to investigate a density profile along the sheet thickness, which was created by some papermaking processes like pressing, drying and calendering. Through the attempt to observe the forming procedure of a fiber network during handsheet making, the CLSM images showed that the pressing stage was considered greatly to contribute to generation of interfiber bonding with removing a free water and partly a bound water between fibers. In addition, the CLSM could be used to illustrate not only a surface profile of paper showing the extent of smoothness or roughness, but also a density profile in a B-direction of the network. Finally it became evident that the CLSM could be used as an excellent tool to predict development in fiber and paper properties before and after mechanical treatment during papermaking processes.