• Proceedings of the Korean Nuclear Society Conference
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• 2005.05a
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• pp.1120-1121
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• 2005

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.1
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• pp.17-28
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• 2012

In this study, we suggest a method for material property evaluation by dual-triangular pyramidal indenters using the reverse analysis. First, we demonstrated that load-displacement curves of conical and triangular pyramidal indenters are different for the same material. For this reason, an independent research on the triangular pyramidal indenter is needed. From FE indentation analyses on various materials, we then investigated the relationships among material properties, indentation parameters and load-displacement curves. From this, we established property evaluation formula using dual-triangular pyramidal indenters having two different half-included-angles. The approach provides the values of elastic modulus, yield strength and strain-hardening exponent within an average error of 3% for various materials.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.6
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• pp.761-768
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• 2022

In the hope of realizing carbon neutrality, Korea has established the goal of expanding the supply of hydrogen electric vehicles through a roadmap to revitalize the hydrogen economy. A prerequisite for successful supply expansion is securing the safety of hydrogen electric vehicles. Certain parts, such as the hydrogen transport pipe and tank, in hydrogen electric vehicles are exposed to high-pressure hydrogen gas over long periods of time, so the hydrogen enters the grain boundary of material, resulting in a degradation of the parts referred to as hydrogen embrittlement. In addition, since the safety of parts utilizing hydrogen varies depending on the type of material used and its environmental characteristics, the necessity for the enactment of a hydrogen embrittlement regulation has emerged and is still being discussed as a Global Technical Regulation (GTR). In this paper, we analyze a hydrogen compatibility material evaluation method discussed in GTR and present a direction for the development of Korean-type hydrogen compatibility material evaluation methods.

• Journal of radiological science and technology
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• v.42 no.4
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• pp.265-270
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• 2019

Mammography is the most useful test for the early diagnosis of breast cancer. The MammoPad can be used for the purpose of reducing the pain felt by the patient due to the pressure of the breast. MammoPad cushion the pressure between the breasts and the equipment and reduce the patient's discomfort. A new material pad was fabricated to solve the problem of the H-pad which is currently in circulation. Quantitative evaluation of SNR and CNR and qualitative evaluation of imitation lesion using ACR Phantom were performed. In the quantitative evaluation, SNR and CNR of Non pad and Filter pad were not statistically significant.(p>0.05) In the qualitative evaluation, Fiber and Imitation lesion of H-pad and Filter pad were statistically significant(p<0.05), and all values of Calcification and Mass were not statistically significant. (p>0.05) In addition, Fiber, calcification, mass, and imitation lesion were not statistically significant in both Non pad and Filter pad.(p>0.05) Through this study, it was confirmed that the newly created Filter pad minimizes image quality degradation and can replace existing products.

• Journal of the Korean Society for Nondestructive Testing
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• v.15 no.2
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• pp.364-370
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• 1995

The purpose of this paper was to develop a nondestructive evaluation method of sintered material by ultrasonic method. The density distribution of sintered material becomes inhomogeneous partially because of the friction between the powder and the die during compaction. The inhomogeneity was investigated by measurement of the energy attenuation coefficient and the shift of the center frequency in the frequency spectrum of the ultrasonic reflection echo. The experimental results showed that the center frequency of reflection wave depended linearly on the density of sintered materials. However, the attenuation coefficient decreased inversely as the density increased. This study shows that the shift of the center frequency in the frequency spectrum of reflection wave can be used to a nondestructive evaluation of sintered materials.

• Korean Journal of Materials Research
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• v.5 no.1
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• pp.75-86
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• 1995

In order to manufacture and produce the components to be used for developing aerospace products, it is essential to determine the conformity of material characteristics to the design requirements. However, since the Korean industry has no experience to develop aircraft and spacecraft, the national certification system has not been established. Hence, it is necessary to define the qualification methodology of material to establish the durability and the safety of aircraft and spacecraft. In this paper the characterization methodology which has been performed in aeronautically advanced countries for determination of conformity in materials and production process is reviewed. The change of material properties due to the space environment and the example of evaluation program of composites for the application of aircraft are presented. so that the foundation of evaluation system for aerospace materials can be initiated.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.53-54
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• 2012

This study is aimed at utilizing LCA processor with BIM LOD, eliciting the problems of the existing environmental assessment by constructing the database for environmental values of green buildings. For these objects, environmental load database of BIM construction material and evaluation process are presented, after matching BIM family based environmental load database which is available during evaluation stage, input-output tables and Korea LCI database to standard item code of public procurement service. It is a important factor in environmental assessment of building to develop database unit of standard item code for BIM and construction material. Thus, the results of this study are expected to provide basic data for improving effectiveness of construction through BIM based environmental load evaluation database. Furthermore, the provided environmental load database unit for construction material is considered to be available as basic information for BIM study by suggesting a processor connecting BIM with LCA and along with this, continuous examination on the connection process is needed.

• Korean Journal of Human Ecology
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• v.7 no.1
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• pp.43-50
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• 2004

The purpose of this study is to reach silk protein added in differing amounts to Jeolpyon, Korean traditional rice cake, using rice powder as its primary material, estimation of the micro organism quality, physicochemical property, sensory evaluation and the property of storage period (20${pm} 5 ^{\circ}C$). In the physicochemical property, the content of proximate composition of rice powder was measured as 38.11% of moisture, 56.62% of total sugar, 5.11% of crude protein, 0.52% of crude lipid, 0.25% of ash. And the raw material of silk protein was measured as 6.61% of moisture, 91.22% of crude protein, 6.41% of crude lipid and 0.75% of ash. The pH of raw material for rice powder and silk protein Jeolpyon showed mild acidity as 6.41 and 6.23, respectively. In rice powder and silk protein, total free sugar contents was 0.89% and 0.02%, and total amino acids contents was 4.28% and 52.21 %, respectively. For sensory evaluation. color, taste, softness and adhesiveness were significantly acceptable in control and adding 1 % silk protein. Control and samples added 1$\sim$3% silk protein had high sensory score color in overall acceptance. In conclusion. Jeolpyon can be manufactured with nutritious Jeolpyon by adding silk protein.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.11
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• pp.746-751
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• 2008

The best plan to reduce the building energy consumption is that the insulation performance should be improved because the insulation and airtight of building envelopes have an effect on the energy consumption basically. New insulation materials, which have the high performance and are above insulation standard, have been developed steadily. Because there are not studies on the building energy rating system and economic evaluation considering new insulation materials, these matters should be studied. In result alternatives, which applied 6 high performance material each, reduce the annual heating energy and raise the building energy rating. Applying the vacuum insulation material(Case 1, 2) and vacuum or triple glazing can retrieves the investment with $120 and $140$\sim$150 per barrel each.

• Journal of radiological science and technology
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• v.45 no.5
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• pp.423-431
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• 2022

The purpose of this study is to present objective information in applying 3D printing technology for PET/CT (Positron Emission Tomography/Computed Tomography) performance evaluation and use it as a basic research that can be applied to various purposes in the future. Phantoms were manufactured with step wedge of ABS(Acrylonitrile Butadiene Styrene) and ACR(Acrylic acid) material. The counts for each ROI(Region of Interest) were analyzed through image acquisition in PET/CT. And the variation rate of counts and CNR(Contrast Noise Ratio) was evaluated. In the counts analysis, the effect of thickness occurred. In addition, in the variation rate analysis, the thickness setting of steps wedge 4 to 5 levels should be considered first. These results minimize quantitative and qualitative changes in the phantom manufactured based on 3D printing, and enable more stable PET/CT performance evaluation. Based on 3D printing in PET/CT, various phantoms are expected to be produced in the future. If the characteristics of each material are considered and applied through the basic research such as this research, the result of the phantom manufactured through 3D printing can be more meaningful and will be used in a wide range.