• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1218-1219
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• 2006

The shrinkage variation of Low Temperature Cofired Ceramics(LTCC) limits the size of the substrates that impose limitations on embedded passive components. This paper focuses on the method of minimizing or controlling planar shrinkage and reducing distortion during firing. The laminated sheets of alumina and glass were sintered at varying temperature, and depending on the amount of the glass ceramics. When the sintered of multi-layer structure with $Al_2O_3/Glass/Al_2O_3$, the glass infiltrated entirely into $Al_2O_3$ layer at the temperature of about $950^{\circ}C$ or higher.

• Journal of the Korean Wood Science and Technology
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• v.44 no.1
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• pp.30-39
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• 2016

The evaluation of the lateral load performance for larch glulam portal frames was carried out using glass fiber reinforced plastic (GFRP) as connector in two different systems: the GFRP-reinforced laminated plates combined with veneer, and GFRP rod joints glued with epoxy resins to replace usual metal connectors for the structural glulam rahmen joints. As a result the yield strength, ultimate strength, initial stiffness of glulams of GFRP rod joints glued with epoxy resin decreased to 49%, 52% and 61% compared to those of the conventional metal connector. This connector will be a stress device where the bonding strength between the GFRP rod and glued laminated timber is important. Thus, there will be a high possibility that a problem may occur when it is applied to the field. On the other hand, the GFRP-reinforced laminated plates and wood (Eucalyptus marginata) pin were measured all within 3% for all measurements of the yield strength, ultimate strength, initial strength and ductility factor, regardless of high cross sectional loss on the glued laminated timber slit joint. In addition, the variation of stiffness on the cycle was 35%, which was the lowest, confirming that it was almost the same performance as the specimen prepared with the metal connector.

• Structural Engineering and Mechanics
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• v.12 no.2
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• pp.169-188
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• 2001

This note presents the main results of an experimental investigation into the mechanical behaviour of a composite sandwich conceived as a lightweight material for naval engineering applications. The sandwich structure is formed by a three-dimensional glass fibre/polymer matrix fabric with transverse piles interconnecting the skins; the core is filled with a polymer matrix/glass microspheres syntactic foam; additional Glass Fibre Reinforced Plastics extra-skins are laminated on the external facings of the filled fabric. The main features of the experimental tests on syntactic foam, skins and sandwich panels are presented and discussed, with focus on both in-plane and out-of-plane responses. This work is part of a broader research investigation aimed at a complete characterisation, both experimental and numerical, of the complex mechanical behaviour of this composite sandwich.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.4
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• pp.507-513
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• 2013

Transparent bulletproof windows play an important role in the munitions industry. The thickness of bulletproof windows including soda-lime silicate(SLS) glass, polyvinyl butyral, poly urethane, main defense(200MD), and safety film was reduced from 40mm to 29mm by adjustment of SLS glass laminated array. Borosilicate glasses generally have lower surface density and more excellent mechanical properties than SLS glass. Borosilicate glass was strengthened by ion exchange in the $KNO_3$ powder. The maximum mechanical properties were observed at $550^{\circ}C$ for 10min. The Vickers hardness, fracture toughness and 3-point bending strength of ion exchanged samples were about $775kg/mm^2$, $1.91MPa{\cdot}m^{1/2}$ and 764MPa each, which are about 27%, 149% and 249% higher than parent borosilicate glass, respectively. The penetration depth of K+ ion at $550^{\circ}C$ for 10min was $59.8{\mu}m$. As a result, the transparent bulletproof windows were predicted to be more lightweight by ion exchange of borosilicate glass. If the SLS glass for bulletproof windows is replaced by ion exchanged borosilicate glass, the bulletproof windows can be expected to be lightweight and thinner.

• Computational Structural Engineering
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• v.6 no.1
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• pp.117-125
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• 1993

In general, the strength and stiffness of laminated composite cylindrical shells are very sensitive to the variation of slenderness parameters, some coupling-stiffness parameters, lamination angles, stacking sequence and number of layers. In this paper, the effects of these factors on the strength and buckling reliabilities of GFRP laminated cylindrical shells are investigated based on the proposed strength and buckling limit state models. As these factors have various and complicated effects on the strength and buckling reliabilities of GFRP laminated cylindrical shells, the results should be incorporated into the design formula such that optimum design technique and design code which provide uniform consistent reliability for balanced design in practice

• Journal of the Korean Solar Energy Society
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• v.34 no.2
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• pp.44-52
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• 2014

The main purpose of this paper is to develop the new BIPV module equipped with vacuum glass. Beacuse BIPV module has a function of architectural materials, thermal and PV performance should be simultaneously evaluated. To improve the thermal performance of BIPV module, this study developed BIPV module equipped with a vacuum glass. Those BIPV module was tested with a variety of encapsulants. The results are as follows. When a vacuum glass is laminated with EVA or PVB, it was broken. The reason seems to be bending by unbalance of heat expansion with center and edge of vacuum glass. In case of lamination with resin, there is no breakage and no bending of vacuum glass. Because production was conducted in low pressure & low temperature conditions. And it was also found that vacuum glass does not interfere with the UV curing process.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.71-75
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• 2005

For the damage tolerance improvement of conventional laminated composites, stitching process have been utilized for providing through-thickness reinforcements. 2D preforms were stacked with S-2 glass plain weave and S-2 glass MWK (Multi-axial Warp Knit) L type. 3D preforms were fabricated using the stitching process. All composite samples were fabricated by RTM (Resin Transfer Molding) process. To examine the damage resistance performance the low speed drop weight impact test has been carried out. For the assessment of damage after the impact loading, specimens were examined by scanning image. CAI (Compressive After Impact) tests were also conducted to evaluate residual compressive strength. Compared with 2D composites, the damage area of 3D composites was reduced by 20-30% and the CAI strength showed 5-10% improvement.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.6
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• pp.509-516
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• 2008

Multi-layer circuit card for semiconductor inspection was fabricated by LTCC technology. After a proper impedance design without electrical interference, ceramic tapes with the composition of $CaO-Al_2O_3-SiO_2-B_2O_3$ glass and $Al_2O_3$ were prepared. The electrode with silver paste printed on the tape. Printed ceramic sheets were then laminated and sintered. Densities and dielectric properties were measured. The microstructure, fracture surface of the region of via and matching state of substrate-electrode were observed. The durability of plated outside electrode were examined by hardness and scratch test.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1114-1115
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• 2008

In this paper, we study the optical characteristics of low iron glass for photovoltaic modules fabrication. Tow types of glasses are examined by optical transmittance and reflection measurement. Also, by making laminated glass, we analyze the difference between glass maker. Mini-PV module is fabricated to compare optical reflectance through lamination process. Anti-reflection and catalyst-coated glasses are suggested for advanced technology to obtain high electrical generation output. The specific analysis is shown in the following paper.

• Journal of the Korean Society of Safety
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• v.29 no.5
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• pp.15-21
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• 2014

The aim of this work is conduct the study on light weight and structural performance improvement of the composite wind power blade. GFRP (Glass Fiber Reinforced Plastic) pre-empted by CFRP(Carbon Fiber Reinforced Plastic), the major material of wind power blade, was identified the superiority of mechanical performance through the tensile and fatigue test. SENT(Single Edge Notched Tension) specimen fracture test was conducted on the specimen that laminated together 2 ply CFRP with 4 ply GFRP through DIC(Digital Image Correlation) analysis. The SENT specimen thickness and $a_0/W$ ratio is 1.45 mm and 0.2, respectively. The fracture test accomplished with displacement control with 0.1 mm/min at the room temperature. The experimental apparatus used for the fracture test consisted of a 50kN universal dynamic tester and CCD camera connected to a personal computer (PC), which was used to record images of the specimen surface. Following data acquisition, the images and load-displacements were transferred to the PC, on which the DIC software was implement. The experiment and DIC analysis results show that CFRP/GFRP laminated composite exhibits improvement of the strength, compared with that of the existing blade material. This study shows the result that the strength of CFRP rotor blade of wind turbine satisfies through the experimental and DIC method.