• International Journal of Precision Engineering and Manufacturing
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• v.8 no.4
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• pp.38-44
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• 2007

Combat vehicles are frequently maneuvered in battlefields when the lives of combatants are being threatened. These vehicles are important elements that influence the consequences of a battle. Their armor must be lightweight and provide excellent protection to ensure successful operations. Ceramic composite armor has recently been developed by many countries to fulfill these requirements. We reviewed previous research to determine an effective armor design, and then fabricated a composite armor structure using $Al_2O_3$ and glass fiber-reinforced polymer. Specimens were manufactured under controlled conditions using different backing plate thicknesses and bonding methods for the ceramic layer and the backing plate. The penetration of an armor-piercing bullet was evaluated from ballistic protection tests. The bonding method between the ceramic layer and the fiber-reinforced polymer influenced the ballistic protection performance. A bonding layer using rubber provided the best protection.

• Journal of Pharmaceutical Investigation
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• v.39 no.1
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• pp.1-6
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• 2009

To overcome the stability problem of hydrophilic quantum dot (Q-dot), cellular uptake of hydrophobic instead of hydrophilic Q-dot was studied in the hope to find a simple method to use Q-dot as a cellular imaging probe. Hydrophobic Q-dot and poly-L-lactic acid (PLLA) were co-dissolved in chloroform to prepare stable films. Due to the cellular compatibility of PLLA, adherent cells were cultured on the film to observe the degree of Q-dot uptake and cytotoxicity of the prepared films. The results show that Q-dots were absorbed into NIH3T3 and EMT6 cells. Cellular uptake was also observed when hydrophobic Q-dots were coated directly on a glass plate. PLLA/Q-dot film and Q-dot coated on glass plate did not show major cytotoxicity. In vivo tumor model was also used to show the uptake of Q-dot from the PLLA/Q-dot film to the tumor site.

• Korean Journal of Optics and Photonics
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• v.9 no.3
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• pp.129-133
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• 1998

The phtocount distributions of a quasi-thermal light source were measured by using the photoelectric counting method. The source was fabricated from the ground glass plate of 9${\mu}{\textrm}{m}$ roughness illuminated by linearly polarized He-Ne laser beam. The coherence time of the quasi-thermal light changed from 31.4$mutextrm{s}$ to 2.48$mutextrm{s}$ according to the grain velocity of the ground glass plate. The photocount distribution showed the Bose-Einstein statistics for a long coherence time compared to the counting time interval, while the distribution approaches the Poisson distribution when the coherence time much shorter than the counting time.

• Journal of the Korean Ceramic Society
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• v.48 no.1
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• pp.86-93
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• 2011

Transparent plasma display can be realized by developing the synthetic chemistry of appropriate nanophosphors and generating nanophosphor-based transparent luminescent layers. For this goal, red-emitting $Y(V_{0.5},\;P_{0.5})O_4$:Eu nanophosphors were synthesized by a facile hydrothermal route at $200^{\circ}C$ for 48 h and the resulting nanophosphors were subsequently annealed at $800^{\circ}C$ at an ambient atmosphere. The crystallographic structure, morphology, and emission property of the as-synthesized and annealed nanophosphors were compared. Choosing 2-methoxyethanol as a dispersion medium and applying a standard sonication, well-dispersed nanophosphor solutions could be prepared. Using these dispersions, visible transparent nanophosphor layers were spin-deposited on glass substrates. By combining $Y(V_{0.5},\;P_{0.5})O_4$:Eu nanophosphor layer/glass substrate as a rear plate with a front plate used in a conventional plasma display panels (PDPs), mini-sized transparent red-emitting PDPs were constructed. Transmittance and luminance properties of two transparent test panels using as-synthesized versus $800^{\circ}C$-annealed nanophosphors were characterized and compared.

• Journal of Power System Engineering
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• v.9 no.4
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• pp.137-142
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• 2005

The effects of temperature and initial crack length on impact fracture behavior of side plate material of 35 ton class FRP ship, which are composed by glass fiber and unsaturated polyester resin, were investigated. Impact fracture toughness of GF/PE composites displayed maximum value when the temperature of specimen is room temperature and $50^{\circ}C$, and with decrease in temperature of specimen, impact fracture toughness decreased. Impact fracture energy of GF/EP composites decreased with increase in initial crack length of specimen, and this value decreased rapidly when the temperature of specimen is lowest, $-25^{\circ}C$,. It is believed that sensitivity of notch on impact fracture energy were increased with decrease in temperature of specimen. As the GF/EP composites exposed in low temperature, impact fracture toughness of composites decreased gradually owing to the decrease of interface bonding strength caused by difference of thermal expansion coefficient between the glass fiber/polyester resin. Further, decrease of interface bonding strength of composites with decrease in specimen temperature was ascertained by SEM photograph of impact fracture surface.

• Journal of Korea Ship Safrty Technology Authority
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• no.7 s.25
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• pp.64-76
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• 2008

This paper describes the failure mechanism and Charpy impact test of Fiber glass Reinforced Plastic composites which it was actually used for side plate of vessel. There are two examinations. The examination I, the specimens which it given temperature range $-25^{\circ}C$-$50^{\circ}C$ and with different initial notch length did impact test and then it compared impact energy(Uc) and impact fracture toughness(GIC). The examination II, the specimens which it putted into fresh water and sea water for scheduled hours did impact test and it compared impact energy(Uc) and impact fracture toughness(GIC). From examination I, it showed that impact energy(Uc) and impact fracture toughness(GIC) were peak at ambient temperature and decrease as temperature reduced. Fracture toughness(GIC) showed increase as initial notch length reduced. From examination II, impact energy(Uc) and impact fracture toughness(GIC) tended to increase which specimens putted in fresh water compared with sea water and maximum tolerance rate tend to decrease as permeation hours will be long.

• Journal of the Korea Institute of Building Construction
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• v.8 no.5
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• pp.43-51
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• 2008

This study examines shear capacity performance and structural characteristics of reinforced concrete beam using carbon fiber sheet(CFS), g)ass fiber sheet(GFS), glass fiber steel plate(GSP) and carbon fiber bar CB) which are reinforcing materials for reinforced concrete beam in order to produce similar condition to repair and reinforce actual structure and aims to provide data available In designing and constructing reinforced concrete structures under the structural damage. This study obtains the following conclusions. After considering the shear experiment results. it was indicated that the CB reinforced test object was the best in the shear capacity improvement and ductility capacity as it was contained in the concrete and was all operated, Also, GFS reinforced test object indicated the reduced flexural capacity but good shear capacity. GSP reinforced test object had bigger reinforcing strength than other reinforcing test objects. On the other hand, it showed the lowest reinforcement effect as compared section thickness of reinforced material because it showed the bigger relativity a section thickness of reinforced material. If the adherence to the concrete is improved, it will seem to show bigger reinforcement effect.

• Nuclear Engineering and Technology
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• v.50 no.3
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• pp.519-525
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• 2018

Obtaining knowledge of the absorbed dose up-taken by a certain material when it is exposed to a specific ionizing radiation field is a very important task. Even though there are a plenitude of methods for determining the absorbed dose, each one has its own strong points and also drawbacks. In this article, an innovative idea for the development of a new gamma-ray dosimetry system is proposed. The method described in this article is based on optical colorimetry techniques. A color standard is fixed to the back of a BK-7 glass plate and then placed in a point in space where the absorbed dose needs to be determined. Gamma-ray-induced defects (color centers) in the glass plate start occurring, leading to a degree of saturation of the standard color, which is proportional, on a certain interval, to the absorbed dose. After the exposure, a high-quality digital image of the sample is taken, which is then processed (MATLAB), and its equivalent $I_{RGB}$ intensity value is determined. After a prior corroboration between various well-known absorbed dose values and their corresponding $I_{RGB}$ values, a calibration function is obtained. By using this calibration function, an "unknown" up-taken dose value can be determined.

• Steel and Composite Structures
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• v.25 no.6
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• pp.685-692
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• 2017

In this study, the effect of various adhesively bonded composite patches on mechanical properties of notched Al-Mg alloy plates was analyzed. For this purpose firstly, the un-notched and notched specimens were fabricated from 5086 Al-Mg alloys which have been used in armor-plated military vehicles. The surface notches as a flaw were machined with circular cutting tool to form notch aspect ratio a/c=0.15 and notch-to-thickness ratios a/t=0.5 in the radial direction on the test specimens. Then, various composite patches which reinforced by glass, carbon and Kevlar fibers were bonded adhesively at elliptically surface notches. Finally, experimental measurements conducted by applying tensile static loading. The experimental results showed that repairing with composite patches with order of carbon, glass and Kevlar fibers have remarkable effect on tensile strength of the notched plate. Also the finite element models were developed using Abaqus/Explicit code to predict the tensile strength and elongation of unrepaired notched specimen and specimen repaired by carbon fiber composite patch. The comparison between numerical and experimental results showed good agreement between them and proved the accuracy of numerical modeling.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.6
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• pp.95-102
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• 2007

Recently, an improved capacity for RC bridges is required by their deterioration or necessary to carry traffic increase. Strengthening is known as a better way to improve capacity of bridges than reconstructing in terms of economy. The surface bonded method, which is normally used with FRP material, has some advantages related to conveninent application and time-save among other strengthening methods. FRP material is light and has high tensile strength compared to steel. Therefore, this paper presents how structural capacity strengthed with CFRP sheet and Glass fiber-Steel Plate (GSP) is improved.