• 대한기계학회논문집A
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• 제27권2호
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• pp.255-261
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• 2003

It is advantageous to use NDE methods to assess the mechanical properties of materials since the conventional method is time-consuming and sometimes requires cutting of sample from the component. The NDE parameters such as ultrasonic velocity and attenuation, electric resistivity, and magnetic coercive force and remanance have been utilized to evaluate changes of material properties due to heat treatment condition. It has been found that changes of materials properties under quenched and tempered/PWHT treatments could not be detected using EMAT and Electrical resistivity methods. However, victors hardness and magnetic hysteresis loop decreased with heat treatment procedures. These results were obtained using 3Cr-lMo-0.25V steel. The magnetic parameters were found to be most sensitive to changes of material properties.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 추계학술대회 논문집
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• pp.405-408
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• 1996

The rheological changes in sensitive materials was investigated by using QCA. Langmuir-Blodgett method was used to transfer sensitive material to the quartz crystals because of its facility to control the thickness. To develop gas sensor using quartz crystal, the rheological change of sensitive LB films were observed using the resonant resistance concept. And the rheological changes as to adsorption of organic vapours were used to analyze the response mechanism between organic vapours and sensitive LB films. We considered with resonant frequency of quartz crystal to obtain one-channel gas sensor and analytical tools of organic vapours response. In our results, we analyzed the organic vapours response by the rheological changes and mass loading as to adsorption of organic vapours.

• 한국정밀공학회지
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• 제20권6호
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• pp.37-46
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• 2003

This paper is to predict quality deterioration resulting from a caulking process of yoke which is a part of automotive steering system. The caluking is a plastic deformation process involving such as impact of high speed tool, contacts between part and fixtures and strain rate sensitivity of the part material. Elaborate application of finite element method is neccesary to calculate changes of part dimensions because they fall into a level of tolerances. Simple work hardening and strain rate sensitive model is proposed fur the material and applied for the simulation by using Abaqus which is able to cater for elastoplastic rate sensitive material and contacts. Numerical results of test models that represent tensile bar and tensile plate are compared with material data inputs. Dimensional changes for the yoke are calculated from simulations and compared to the mesurements and they show good agreement. The method presented here with the material model proved to be valuable to assess quality deterioration for similar metal forming processes.

• 복식문화연구
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• 제19권1호
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• pp.119-127
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• 2011

This purpose of this study was to analyze the formation and look into design characteristics by types and method of expression on multifunctional eco-friendly fashion design. Total 191 pieces of multifunctional fashion design photographs were collected through fashion collection from 2000 S/S to S/S 2010 F/W on the website. First, the characteristics of multifunctional eco-friendly fashion design used squared silhouette, achromatic colors, plain patterns for pollution control, hard materials to prolong the product, it was clear that details were minimized to save resources. Second, there were 5 changeable types of multifunctional eco-friendly fashion design which were changes in changing forms, material changes, item changes, detail changes and complex changes. Third, as the result of changeable types by method of expression, the changing forms were expressed by removable, material changes by reversible, detail changes by open and close and item changes by shifting. Forth, the formative properties of multifunctional eco-friendly fashion design had flexibility, multifunction, versatility and amusing. Therefore, this study will be helpful in planning multifunctional eco-friendly fashion design according to the kind of formative characteristics, changeable types, method of expression and provide concrete fundamental materials for the expert in clothing on the base of objective data through statistical analysis.

• Advances in concrete construction
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• 제9권5호
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• pp.459-467
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• 2020

Mechanical and thermal properties of composite sandwich wall panels are affected by changes in their external environment. Humidity and temperature changes induce stress on wall panels and their core connectors. Under the action of ambient temperature, temperature on the outer layer of the wall panel changes greatly, while that on the inner layer only changes slightly. As a result, stress concentration exists at the intersection of the connector and the wall blade. In this paper, temperature field and stress field distribution of UHPC-RW-RC (Ultra-High Performance Concrete - Rock Wool - Reinforced Concrete) wall panel under high temperature-sprinkling and heating-freezing conditions were investigated by using the general finite element software ABAQUS. Additionally, design of the connection between the wall panel and the main structure is proposed. Findings may serve as a scientific reference for design of high performance composite sandwich wall panels.

• Nuclear Engineering and Technology
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• 제49권4호
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• pp.700-709
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• 2017

This work looks at the effect of changes in kinetic parameters on simultaneous reactivity insertions and beam tube flooding in a typical material testing reactor-type research reactor with low enriched high density ($U_3Si_2-Al$) fuel. Using a modified PARET code, various ramp reactivity insertions (from $0.1/0.5 s to $1.3/0.5 s) plus beam tube flooding ($0.5/0.25 s) accidents under uncontrolled conditions were analyzed to find their effects on peak power, net reactivity, and temperature. Then, the effects of changes in kinetic parameters including the Doppler coefficient, prompt neutron lifetime, and delayed neutron fractions on simultaneous reactivity insertion and beam tube flooding accidents were analyzed. Results show that the power peak values are significantly sensitive to the Doppler coefficient of the system in coupled accidents. The material testing reactor-type system under such a coupled accident is not very sensitive to changes in the prompt neutron life time; the core under such a coupled transient is not very sensitive to changes in the effective delayed neutron fraction.

• 대한치과교정학회지
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• 제48권3호
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• pp.172-181
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• 2018

Objective: This study was performed to investigate buccal facial depth (BFD) changes after extraction and nonextraction orthodontic treatments in post-adolescent and adult female patients, and to explore possible influencing factors. Methods: Twelve and nine female patients were enrolled in the extraction and nonextraction groups, respectively. Changes in BFD in the defined buccal region and six transverse and two coronal measuring planes were measured after registering pretreatment and posttreatment three-dimensional facial scans. Changes in posterior dentoalveolar arch widths were also measured. Treatment duration, changes in body mass index (BMI), and cephalometric variables were compared between the groups. Results: BFD in the buccal region decreased by approximately 1.45 mm in the extraction group, but no significant change was observed in the nonextraction group. In the extraction group, the decrease in BFD was identical between the two coronal measuring planes, whereas this differed among the six transverse measuring planes. Posterior dentoalveolar arch widths decreased in the extraction group, whereas these increased at the second premolar level in the nonextraction group. The treatment duration of the extraction group was twice that of the nonextraction group. No differences were found in BMI and Frankfort horizontal-mandibular plane angle changes between the groups. BFD changes in the buccal region moderately correlated with treatment duration and dental arch width change. Conclusions: BFD decreased in adult female patients undergoing extraction, and this may be influenced by the long treatment duration and constriction of dentoalveolar arch width. However, nonextraction treatment did not significantly alter BFD.

• 한국의사학회지
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• 제31권1호
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• pp.135-147
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• 2018

Analyzing the Book of Changes, researchers noted that animals and plants utilized as symbols in the Book of Changes were later used as medicinals in East Asian medicine. They found 24 animals and plants utilized as symbols in the Book of Changes; specifically in six statements on the hexagrams and 53 statements on the lines. The animal and plant symbols in 59 statements are more clearly interpreted with the descriptions in the Compendium of Materia Medica. Eleven plants referenced in the Book of Changes were written with their nicknames, causing confusion to the researchers of later times. Using the Compendium of Materia Medica however, these plants can be identified. Livestock were mentioned 34 times among the 59 statements, with horse and cattle being the most often at eight times, each. They are subdivided according to their sex and color. The writers of the Book of Changes constructed an elaborate symbol system with the animals that are familiar to people, and which, through this research, has been decoded through cross references to the Compendium of Material Medica.

• 한국의상디자인학회지
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• 제17권3호
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• pp.29-43
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• 2015

This study investigates transformable designs in contemporary fashion. In contemporary society, designs are accompanied by various changes such as transformation of shapes or variation of material beyond the certain form of dress. As a result of having interest in transformable designs with the various attempts on the overall design, transformable design is being suggested as an attempt as the new manner, radical concept, or alternative of multi-purpose lifestyle. With the constant research and collection presentation by the designers of empirical disposition, transformable dress has been evolving gradually. The feature of transformable design appeared in dress is considered as 'variability' which changes in the flow of time. Furthermore, the morphological variability and variability of material have been examined as visual stimuli and conversion of material. By analyzing and assorting diverse transformable dresses comprehensively, it could be divided into technique-oriented transformable design and transformable design with a wearer's intervention. The technique-oriented transformable design is subdivided into the conversion of material and the conversion of form; the transformable design with a wearer's intervention into the conversion of functional frame and the conversion of aesthetic feature.

• 한국재료학회지
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• 제26권11호
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• pp.662-669
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• 2016

In order to identify changes in the nature of the particles due to changes in the inflow rate of the raw material solution, the present study was intended to prepare nano-sized cobalt oxide ($Co_3O_4$) powder with an average particle size of 50 nm or less by spray pyrolysis reaction using raw cobalt chloride solution. As the inflow rate of the raw material solution increased, droplets formed by the pyrolysis reaction showed more divided form and the particle size distribution was more uneven. As the inflow rate of the solution increased from 2 to 10 ml/min, the average particle size of the formed particles increased from about 25 nm to 40 nm, while the average particle size did not show significant changes when the inflow rate increased from 10 to 50 ml/min. XRD analysis showed that the intensity of the XRD peaks increased remarkably when the inflow rate of the solution increased from 2 to 10 ml/min. On the other hand, the peak intensity stayed almost constant when the inflow rate increased from 10 to 50 ml/min. With the increase in the inflow rate from 2 to 10 ml/min, the specific surface area of the particles decreased by approximately 20 %. On the contrary, the specific surface area stayed constant when the inflow rate increased from 10 to 50 ml/min.