• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.846-851
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• 2017

Piezoelectricity is the capability of a piezoelectric material to change mechanical energy into electrical energy. The determination of electrical and mechanical properties plays a significant role in characterizing the piezoelectric material. The energy losses characteristics of piezoelectric material can be described by mechanical quality factor. In this paper, the output voltage and mechanical quality factor of Lead Zirconate Titanate (PZT-4A) piezoelectric material is determined under various resistance and loading conditions by using the test setup. The commercial FEM software ABAQUS is used to analyze the performance of piezoelectric material under static loading conditions. It is observed that these properties affect the performance of a material particularly in the designing of smart structures. The experimental results are partially compared to the simulation values.

• 대한기계학회논문집A
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• 제22권3호
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• pp.654-662
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• 1998

Shift quality of an automatic transmission in a vehicle is mainly affected by transient pressures in the hydraulic system during shifting. In this study, dynamic modelings of the hydraulic system and the power train of an automatic transmission are made systematically by a bond-graph method. The dynamic characteristics of the line pressures and clutch/brake pressures during shiftings are investigated by simulations and verified by experiments. The effects of clutch/brake pressures on the shift torque are also investigated through driving simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 C
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• pp.1510-1512
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• 1997

Piezoelectric characteristics of lead zirconate(PZ)-lead titanate(PT)-lead manganese antimony(PMS) ceramics with the various changes of calcination temperature in PMS were prepared. The range of their sintering temperature was from $1100^{\circ}C$ to $1250^{\circ}C$. The electro-mechanical properties of PZ-PT-PMS ceramics such as piezoelectric constant, electro-mechanical coupling coefficient, and mechanical quality factor are measured as a function of the calcination temperature of PMS. As increasing the calcination temperature of PMS mechanical quality factor is increased.

• 한국안전학회지
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• 제20권3호
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• pp.9-13
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• 2005

Inconel 625 is useful in variety of industrial applications because of the resistance to attack on various corrosive media at temperature from $200^{\circ}C$ to over $1090^{\circ}C$, in combination with good low and high temperature mechanical strength. Recently, this material is also used widely in offshore processing piping in order to extend the maintenance term and improvement the quality of anti-corrosion. In general, high quality weldments for this material are readily produced by commonly used processes. Not all processes are applicable to this material group, Ni-alloys. Metallurgical characteristics or the unavailability of matching, position or suitable welding process. Nowadays, the flux cored wire is developed and applied for the better productivity in several welding position including the vertical position. In this study, the weldability and weldment characteristics(mechanical properties) of inconel 625 are considered in FCAW(Flux Cored Arc Welding) associated with the severial shielding gases($80%Ar+20%CO_2,\;50%Ar+50%CO_2,\;100%CO_2$) in viewpoint of welding productivity.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 봄 학술발표회 논문집
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• pp.88-93
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• 1995

The purpose of this study is to investigate the mechanical properties and durability of high-quality concrete containing silica fume. For this purpose, the optimum quantity of silica fume were obtained for high-quality concrete, and the mechanical properties and durability of it are analyzed according to amount of combined material.

• 동아시아식생활학회지
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• 제23권1호
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• pp.78-84
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• 2013

Powders prepared from three different varieties of Korean ginseng (white, red and black) are consumed daily by many Koreans as a functional food material. These variants exert a variety of physiological effects. The principal objective of this study was to evaluate the quality characteristics of Yanggaeng prepared with three different types of ginseng powder. We conducted tests for ginsenosides content, Hunter's color values, mechanical characteristics, and sensory evaluation analysis. The ginsenosides of black ginseng were higher than those of white and red ginseng. The lightness of the black ginseng Yanggaeng was significantly less than the white, red, and control samples (p<0.05). We noted significant differences in Hunter's a and b values. With regard to the mechanical properties of the samples, we noted significant differences in gumminess (p<0.05), but no differences in hardness, springiness, chewiness, and cohesiveness were detected. The results of sensory evaluation showed that there were significant differences in the color, flavor, and overall quality of the samples (p<0.05), but there were no significant differences in taste and texture. Overall, red ginseng Yanggaeng appeared to have the most commercial value for improving the Yanggaeng product.

• Journal of Mechanical Science and Technology
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• 제20권12호
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• pp.2025-2033
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• 2006

This paper presents, the design of a latch mechanism for wafer containers in a standard mechanical interface environment. For an integrated circuits fabrication factory, the standard mechanical interfaced wafer container is an effective tool to prevent wafers from particle contamination during wafer storage, transporting or transferring. The latch mechanism inside the container door is used to latch and further seal the wafer container for safety and air quality. Kinematic characteristics of the mechanism are established by analyzing the required functions of the mechanisms. Based on these characteristics, a methodology for enumerating feasible latch mechanisms is developed. New mechanisms with one degree-of-freedom and up to five links are generated. An optimum design is also identified with respect to the criteria pertinent to the application. The computer-aided simulation is also built to verify the design.

• 동아시아식생활학회지
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• 제23권5호
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• pp.561-568
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• 2013

This study was conducted to evaluate the quality characteristics of darae (Actinidia arguta) jelly, a snack for elementary school children, prepared with darae extract. To establish the amount of darae extract (0~4%) that could be added to jelly, the physicochemical sensory characteristics and mechanical properties were measured. As the amount of darae extract increased, the values of L and b were decreased, whereas the a value was increased. Sensory evaluation of the sweetness, taste, flavor, texture and overall acceptability of jelly prepared using 2% darae extract resulted in a high score. Among the mechanical properties, by increasing darae extract only the hardness of the extract was significantly decreased. The results of this study suggest that darae extract can be useful in the production of high quality jelly. Thus, it can be served as a substitute for existing high calorie commercial snacks for children.

• 한국소음진동공학회논문집
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• 제26권2호
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• pp.121-129
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• 2016

The noise pattern of a household refrigerator is dependent on the characteristics of its operating cycle which is repeated with a specific pattern depending on various parameters, such as room temperature and performance of its mechanical parts. Analysis of noise pattern is essential prior to evaluation of sound quality of a refrigerator. In this study, 14 units of refrigerator were classified into 4 types according to noise pattern and sort of mechanical part, which helps to analyze characteristics of refrigerator noise. Sound quality metrics(loudness, sharpness, roughness, and fluctuation strength) were calculated to compare noise pattern of the 4 types of refrigerator. The results of this study can be useful to decide noise performance of refrigerator.

• Elastomers and Composites
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• 제51권4호
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• pp.275-279
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• 2016

Additive manufacturing or 3D printing is a new manufacturing process and its application is getting growth. However, the product qualities such as mechanical strength, dimensional accuracy, and surface quality are low compared with conventional manufacturing process such as molding and machining. In this study not only mechanical characteristics of polymer sandwich panel having three dimensional core layer but also mechanical characteristics of core layer itself were analyzed. The shape of three dimensional core layer was pyramidal kagome structure. This core layer was fabricated by two different methods, injection molding with PP resin and material jetting type 3D printing with acrylic photo curable resin. The material for face sheets in the polymer sandwich panel was PP. Maximum load, stiffness, and elongation at break were examined for core layers fabricated by two different methods and also assembled polymer sandwich panels. 3D printed core showed brittle behavior, but the brittleness decreased in polymer sandwich panel containing 3D printed core. The availability of 3D printed article for the three dimensional core layer of polymer sandwich panel was verified.