• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04b
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• pp.77-80
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• 2004

In this study, the purpose is to verified the feasibility to develope Hybrid x-ray detector in order to resolve problems of direct and indirect x-ray detectors. The properties of X-ray detector depend on absorption of X-ray, charge generation by x-ray photon, leakage current. In this study, CdS was used as photoconductor, and $Y_2O_2S:Tb$ as x-ray phosphor was formed on CdS in order to embody Hybrid structure. And Screen printing was used to form Muli-layer. Characteristics of this specimen were analyzed by using SEM, and XRD. And Photoluminescence spectrum of $Y_2O_2S:Tb$, leakage current, with respect to applied voltages, output charge with respect to applied voltages, and X-ray sensitivity were measured. Also, linearity with respect to dose was measured. Leakage current was similar with direct digital x-ray detector, but sensitivity of the hybrid structure is much better than the single-layer structure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.6
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• pp.451-455
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• 2012

To compare an electrical and optical characteristics of indium tin oxide (ITO) and carbon nanotube (CNT) electrode on flexible and reflective display, we fabricate two charged particle-type display panels under the same panel condition of which the width of ribs is 10 ${\mu}m$, the cell size is $300{\mu}m{\times}300{\mu}m$, the q/m value of the white particles is -4.3 ${\mu}C/g$ and that for the black is +1.3 ${\mu}C/g$, and the cell gap is 75 ${\mu}m$, 125 ${\mu}m$, and 175 ${\mu}m$. We use plastic substrates coated with ITO and CNT electrode. To evaluate optical property, we measure a response time of particles using a laser and a photodiode. Threshold and driving voltages of CNT electrode according to the sheet resistance of 300, 600, 1,000 (ohm/sq) are compared with ITO electrode of 10 (ohm/sq). A response time of the CNT panel is similar to that of ITO panel, but the threshold and driving voltages of CNT panel are higher than that of ITO panel, inducing a large bombardment of the particles and shortening the lifetime of the panel. High difference of a threshold and a driving voltage of CNT panel will induce an particle clumping, resulting degradation of the panel. A bending radius of the fabricated CNT panel is 18 ${\mu}m$.

• Journal of the Korean Institute of Gas
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• v.15 no.4
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• pp.21-26
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• 2011

Type-3 cylinder liner has a limitation of machining the standard specimen for fracture toughness test because it has approximately 5 mm in thickness as well as a curvature. Hence, it needs to be employed a miniature specimen test technique to evaluate fracture toughness of the cylinder liner. In this study, small punch (SP) test method was employed to evaluate fracture toughness of the cylinder liner. Load-displacement curve result measured from the SP test showed that the liner material was failed during membrane stretching in the general SP load-displacement curve. Additionally, it was shown that liner material was isotropic although the amount of plastic deformation was different depending on the direction due to manufacturing process characteristics. Fracture toughness, $J_{Ic}$, was evaluated using the SP test data. The value of fracture toughness obtained was $13.0kJ/m^2$. This value was similar to that of the same kind of materials. Therefore, the fracture toughness evaluated using the SP test data was reasonable.

• The Journal of Advanced Prosthodontics
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• v.12 no.5
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• pp.251-258
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• 2020

PURPOSE. The bond strengths between resin denture teeth with various compositions and denture base resins including conventional and CAD/CAM purposed materials were evaluated to find influence of each material. MATERIALS AND METHODS. Cylindrical rods (6.0 mm diameter × 8.0 mm length) prepared from pre-polymerized CAD/CAM denture base resin blocks (PMMA Block-pink; Huge Dental Material, Vipi Block-Pink; Vipi Industria) were bonded to the basal surface of resin teeth from three different companies (VITA MFT^®; VITA Zahnfabrik, Endura Posterio^®; SHOFU Dental, Duracross Physio^®; Nissin Dental Products Inc.) using resin cement (Super-Bond C&B; SUN MEDICAL). As a control group, rods from a conventional heat-polymerizing denture base resin (Vertex™ Rapid Simplified; Vertex-Dental B.V. Co.) were attached to the resin teeth using the conventional flasking and curing method. Furthermore, the effect of air abrasion was studied with the highly cross-linked resin teeth (VITA MFT^®) groups. The shear bond strengths were measured, and then the fractured surfaces were examined to analyze the mode of failure. RESULTS. The shear bond strengths of the conventional heat-polymerizing PMMA denture resin group and the CAD/CAM denture base resin groups were similar. Air abrasion to VITA MFT^® did not improve shear bond strengths. Interfacial failure was the dominant cause of failure for all specimens. CONCLUSION. Shear bond strengths of CAD/CAM denture base materials and resin denture teeth using resin cement are comparable to those of conventional methods.

• Journal of the Korean Society of Safety
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• v.24 no.2
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• pp.83-88
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• 2009

The objective of this paper was to evaluate the effectiveness of horizontal, vertical, asymmetric and coupling multipliers for manual material handling. Lifting tasks with 5 different horizontal distances ($30{\sim}70cm$) for 6 vertical distances(ankle, knee, waist, elbow, shoulder and head height) were experimented. The muscle activity and muscle exertion level during asymmetric load handling(without trunk flexion) was experimented. Lifting tasks with and without handle tote box for three postures(straight, bending, right angle posture) were experimented. The degrading tendency did not appeared almost in $60{\sim}70cm$ interval's horizontal distance. As a result of ANOVA, MVC paid attention to horizontal and vertical distance but cross effect was insignificant(p<0.01). The change of the MVC according to the horizontal, vertical distance appeared similar from of RWL. The results of normalized MVC measurement were decreased about 16%, 24%, 34% respectively as the asymmetry angle was $30^{\circ}$, $60^{\circ}$, $90^{\circ}$. RMS EMG values of right erector spinae muscles were decreased as the work posture went to $90^{\circ}$ and those of left erector spinae muscles were increased until the asymmetry angle was $40^{\circ}$ but decreased continually over $40^{\circ}$. 7 subjects, activities of left and right latissimus dorsi muscles were maintained constantly, while for remainer, those were irregular. MVC reduced maximum 23% by type of handle. MVC was highest in straight posture, but was lowest in right angle posture. As a result of ANOVA, MVC paid attention to posture, coupling(p<0.01). To all handle types, biceps brachii activity was increased in right angle posture, but reduced in straight posture. Based on the results of this study, it is suggested that the NIOSH guideline should not be directly applied to Korean without reasonable reexamination. In addition, we need to afterward study through an age classification.

• Journal of the Korean Geosynthetics Society
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• v.15 no.2
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• pp.1-12
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• 2016

In this study, laboratory mixture design test and field test were performed to evaluate applicability of eco-friendly binder material (CMD-SOIL) using desulfurized dust in deep cement mixing method (DCM). As a result of laboratory mixture design test, the uniaxial compressive strength of CMD-SOIL was up to 1.136 times bigger than slag cement by changing the water content, mixing rate, and W/B. Also, it had shown the strength up to 1.222 times bigger in shell content and up to 1.363 times in mixing of floating soil. As a result of field test, field strength/laboratory design criterion strength ratio (${\lambda}$) is shown 0.77. And this result was similar to earlier studies. From this result, CMD-SOIL can show the same efficiency compared with existing binder.

• Structural Engineering and Mechanics
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• v.64 no.3
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• pp.361-379
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• 2017

In this article, the vibration behavior of double-bonded sandwich microplates with homogeneous core and nanocomposite facesheets reinforced by carbon nanotube and boron nitride nanotube under multi physical fields such as 2D magnetic and electric fields is investigated. Symmetric and un-symmetric distributions of nanotubes are considered for facesheets of sandwich microplates such as uniform distribution and various functionally graded distributions. The double-bonded sandwich microplates rest on visco-Pasternak foundation. Material properties of sandwich microplates are obtained by the extended rule of mixture. The sinusoidal shear deformation theory (SSDT) is employed to describe displacement fields of sandwich microplates. Also, the dimensionless natural frequency is obtained by classical plate theory (CPT) and compared with the obtained results by SSDT. It can be seen that the obtained dimensionless natural frequencies by CPT are higher than SSDT. In order to study the material length scale parameters, modified strain gradient theory at micro scale is utilized and then, the equations of motion are derived using Hamilton's principle. The effects of different parameters such as foundation parameters including Winkler, shear layer and damping coefficients, various distributions and volume fraction of nanotubes, core to facesheet thickness ratio, aspect and side ratios on the dimensionless natural frequencies are discussed in details. The results of present work can be used to optimum design and control of similar systems such as micro-electro-mechanical and nano-electro-mechanical devices.

• Advances in concrete construction
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• v.9 no.6
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• pp.537-545
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• 2020

In order to reduce the usage of cement slurry in grouting engineering and consume the tunnel excavation waste soil, a new geopolymeric grouting material (GGM) was prepared by combine completely weathered granite (CWG) and blast-furnace slag (BFS), which can be applied to in-situ grouting treatment of completely weathered granite strata. The results showed CWG could participate in the geopolymerization process, and GGM slurry has the characteristics of short setting time, high flowability, low viscosity, high stone rate and high mechanical strength, and a design method of grouting pressure based on viscosity evolution was proposed. By adjusted the content of completely weathered granite and alkali activator concentration, the setting time of GGM were ranged from 5 to 30 minutes, the flowability was more than 23.5 cm, the stone rate was higher than 90%, the compressive strength of 28 days were 7.8-16.9 MPa, the porosity were below 30%. This provides a novel grouting treatment and utilizing excavated soil of tunnels in the similar strata.

• Fashion & Textile Research Journal
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• v.17 no.1
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• pp.11-21
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• 2015

This study analyzed the expressive phenomenon of a blurred boundary in fashion jewelry focused on the relationship between fashion jewelry and costume or fashion jewelry and body. The method of this study was to analyze recent documentaries about jewelry theories in regards to 607 cases of fashion jewelry design in fashion books, fashion magazines, fashion internet sites from 2000 to 2014. The results were: First, phenomenon of blurred boundary between fashion jewelry and costume was expressed in a see-through wear form made of luxury material (gold and diamond) or paste material, a similar form (like fashion accessories made of crystal, bids, and gold chain), an integration of fashion accessories and jewelry, and an attached jewelry on fashion accessories. It reflected a rearrangement of conventional relationships, a blurred relation of function and meaning, dissolution of jewelry form stereotypes, jewelry styling, a harmony of function and decoration, and an alteration to the central role of a fashion image. Second, the phenomenon of a blurred boundary between fashion jewelry and body was expressed in a body organ wrapping, body surface adhesion and sculptural jewelry based on body pose. It reflected a separation from conventional space of jewelry expression, a realization of mystery and fantastic, an expression of new body surface and a blurred boundaries of fashion jewelry and body art. Aesthetic characteristics were analyzed into metaphor and integration by separation from the conventional relationship of fashion jewelry and costume or fashion jewelry and body.

• Korean Journal of Human Ecology
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• v.24 no.2
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• pp.297-325
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• 2015

The purpose of this research is to analyze content elements of Housing area in 2013 middle school Technology Home Economics textbooks 1 and 2, total of 22 according to 2009 revised curriculum. The analysis method was content analysis, focusing on contents of main text, tables & figures, reading material, and activity materials by their content elements. This research will contribute in obtaining suggestion for the post curriculum/textbook development and helping teachers to perform a lesson. The results are as follows. First, Housing area included 1 to 4 content elements per each units, from 2 chapters and 6 units. The content elements stated in Home economics curriculum were total of 16 which consists of 'the meaning of housing,' 'housing types,' 'family forms,' 'family life style cycle,' 'life style,' 'neighboring environment,' 'co-living values,' 'air environment,' 'heat environment,' 'light environment,' 'acoustic environment,' 'space division,' 'circulation', 'effective use of space,' and 'sustainable dwelling practice.' All of these components are dealt with in every textbooks. Second, the numbers of content elements provided in each textbooks were the same, however they showed difference in their contextual aspect. Some contents need supplemental material for their lacking content element. Others need proper understanding of the concept because some showed different contents from the appropriate content elements. Third, repetitions in content elements were observed, the contents of 'co-living values' in textbook 1 and 'sustainable dwelling practice' in textbook 2 were similar in terms of eco-friendly housing, co-housing and universal housing. These two content elements should be merged as one next curriculum, or should be stated together in one subunit.