• Journal of the Korean Magnetics Society
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• v.15 no.3
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• pp.191-197
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• 2005

In the fabrication process of Fe-based amorphous alloy powder cores by pulverization of the melt-spun ribbons and cold compaction, the effects of powder preparation method on the magnetic & electric properties, powder shapes and microstructure of cores have been investigated. The powder cores made by using rotor mill showed low effective permeability as compared to the cores prepared by ball milling. However the frequency dependence and quality factor properties were superior in the case of rotor-milling. Further the powders prepared by rotor mill had homogeneous and round shapes through strong shearing in the sieve ring, while the ball milled powders were inhomogeneous and relatively small. The lower permeability of the powder cores fabricated with rotor mill was considered to be due to the high internal stress occurred by very intensive shearing. Moreover the powder cores produced by rotor-milling showed lower core loss and good frequency dependence of effective permeability possibly due to the higher electrical insulation between magnetic particles. The dc bias property of the powder cores made by rotor-milling was better than the one by ball-milling.

• Journal of Aerospace System Engineering
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• v.12 no.3
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• pp.64-69
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• 2018

The high-velocity electromagnetic forming (EMF) process is based on the Lorentz force and the energy of the magnetic field. The advantages of EMF include improved formability, wrinkle reduction, and non-contact forming. In this study, the electromagnetic-structural interlocking analysis was performed in order to analyze the moldability of aluminum pipe using electromagnetic molding. The magnetic flux density was decreased due to increasing electrical resistance as the temperature increased, and the stress-strain curve decreased. The higher the temperature, the lower the flow stress, increasing deformation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.1
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• pp.169-175
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• 2009

In this experiment molybdeum oxide($MoO_3$) films were prepared by a magnetic null discharge(MND) sputtering system and fundamental properties by XRD, XPS and SEM analysis were investigated. The initial and mean insulation resistance of the same with $MoO_3$ film were about 1.4[$M{\Omega}$] and 800[$k{\Omega}$] under the condition of applied voltage of 400[V]. The preferred orientation in the films changed from(100) to (210) with substrate temperature. Two XPS peaks of the $MoO_3$ photoelectron were detected at the binding energies of 228.9[eV] and 232.4[eV], while the binding energy of the O1s peak was 532.6[eV]. The substrate temperature and reactivity gives large effects to the structure and growth of the film and system is also very useful for performing the uniform reactive deposition. It can be found from the result of a $MoO_3$ film deposition that the system is very useful for performing the uniform reactive sputtering.

• Korean Journal of Optics and Photonics
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• v.24 no.5
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• pp.245-250
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• 2013

The Wiener-Khinchin theorem, which means that the autocorrelation function of a signal corresponds to the power spectrum of the signal, is very important in signal processing, spectroscopy and telecommunications engineering. However, because of needs for some relatively expensive equipments such as a correlator and the signal processing system, its demonstration in most undergraduate class is not easy so far. Recently, digital oscilloscopes whose functions can be replaced foresaid equipments are marketed with development of digital engineering. In this paper, a simple demonstration of the theorem is given by a digital storage oscilloscope and a personal computer with its theoretical background. The reason that deals again with this theorem which has been introduced in 1930 is that it has been not well informed yet to us and theoretical background of the demonstration is directly introduced from its driving process. Through deriving process of the theorem, some extended physical meanings of the impedance, power, power factor, Wiener spectrum, linear system response and, furthermore, basic idea of the Planck's quantization in the black body theory reveal themselves naturally. Hence it can be referred to lectures in general physics, modern physics, spectroscopy and material characterization experiment.

• Proceedings of the Korea Society of Costume Conference
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• 2001.04a
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• pp.41-41
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• 2001

본 연구는 1990년대 밀리터리 패션에서 성적 이미 지의 표현양상을 살펴보고 각각의 미적 특성과 형성 요인을 분석하여 현대 여성의 다양한 미적 가치와 미의식을 이해하고자 한다. 1, 2차 세계대전을 계기로 자연스럽게 등장한 밀 리터리 패션은 20세기 초반에 여성의 사회참여와 지 위 향상으로 인해 실용성과 기능성을 추구하였고 중 반에 들어서면서 히피와 젊은 세대들에 의해 반전운 동의 일환으로 입혀져 안티패션의 의미를 내포하게 되었으며 후반에는 포스트모더 니즘으로 인해 다양성 을 추구하는 복고풍의 패션 트랜드로서 각종 컬혜션 에서 부각되었다. 그 결과 밀리터리 패션은 기존의 남성적 이미지뿐만 아니라 여성적 이미지도 표현하 게 되었다. 이러한 밀리터리 패션에 나타난 성적 이 미지는 권위적 이미지와 공격적 이미지의 남성적 이 미지와 보수적 이미지와 과시적 이미지, 관능적 이미 지의 여성적 이미지로 표현되어 나타났다. 남성적 이미지는 자유주의 페미니즘과 관련하여 남성 중심적 사고 방식에 도전하고자 하는 여성들의 자아의식이 한층 강하게 작용한 일종의 반 패션 현 상으로 권위적 이미지와 공격적 이미지로 특정지을 수 있다. 첫째, 권위적 이미지는 주로 고전적 군복과 제복의 이미지를 차용해 군복이 가지는 권위와 위엄을 표출 하였으며 남성 우월주의에 기초한 영웅주의를 가시 적으로 표현하였다. 이는 떳떳하게 자신의 위치를 세 우고자 하는 여성들의 욕구를 대변하였으며 영웅주 의와 가부장제도가 그 형성요인으로 작용하였다. 둘째, 공격적 이미지는 권위적 이미지에 대한 저 항과 기존의 성 정체성에 대한 저항으로써 전위적인 형태와 해체적인 표현으로 본래의 위엄있는 군복의 이미지를 무너뜨려 남성다웅의 표면적인 메시지를 약화시키고자 하였으며 반체제 정신, 성 정체성에 대 한 저항, 해체주의가 그 형성요인으로 작용하였다. 여성적 이미지는 급진주의 페미니즘과 관련하여 여성 본래의 성을 부각시키고 여성이 주체가 된 여 성중심적 사고로 여성의 감성적 심리를 패션을 통해 표현하고자 하였으며 보수적 이미지, 과시적 이미지, 관능적 이미지로 특징 지을 수 있다. 첫째, 보수적 이미지는 남성적 영역이라고 믿어왔 던 군복에 여성성을 강조하여 가늘고 유연한 실루엣 과 곡선적인 라인, 색채. 심플한 디테일만으로 밀리 터리 패션을 표현하여 남성중심의 이데올로기에서 벗어나 여성도 사회의 중심이 될 수 있음을 시사하 였으며 남성 권위의 추락이 그 형성요인으로 작용하 였다. 둘째, 과시적 이미지는 전통적 군복이 과거의 상 류층 엘리트들만의 아이템이었듯이 현대의 여성들은 신분과 매력의 과시를 표현하고자 금속 단추나 벨트 등 기타장식을 부각시킨 밀리터리 패션을 착용하였 으며 엘리트층에 대한 동경이 그 형성요인으로 작용하였다. 셋째, 관능적 이미지는 신체의 간접적인 노출과 직접적인 노출을 통해 여성의 신체에 의한 에로틱한 관능미를 부여하고자 하였으며 나르시시즘과 보이고 자 하는 욕구, 성적 유희가 그 형성요인으로 작용하였다. 그러므로 밀리터리 패션에 나타난 성적 이미지에 관한 연구는 패션을 통해 자아를 표현하고 미적으로 자기완성의 방편을 삼으려고 한 현대 여성들의 가치 관과 미의식을 이해하며 이를 충족시키고자 하는 패 션 트랜드와 디자인 개발에 도움이 될 것이다.

• Journal of the Korean Magnetics Society
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• v.17 no.2
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• pp.81-85
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• 2007

MnTe layers of high crystalline quality were successfully grown on Si(100) : B and Si(111) substrates by molecular beam epitaxy (MBE). Under tellurium-rich condition and the substrate temperature around $400^{\circ}C$, a layer thickness of $700{\AA}$ could be easily obtained with the growth rate of $1.1 {\AA}/s$. We investigated the structural, magnetic and transport properties of MnTe layers by using x-ray diffraction (XRD), superconducting quantum interference device (SQUID) magnetometry, and physical properties measurement system (PPMS). Characterization of MnTe layers on Si(100) : B and Si(111) substrates by XRD revealed a hexagonal structure of polycrystals with lattice parameters, ${\alpha}=4.143{\pm}0.001{\AA}\;and\;c=6.707{\pm}0.001{\AA}$. Investigation of magnetic and transport properties of MnTe films showed anomalies unlike antiferromagnetic powder MnTe. The temperature dependence of the magnetization data taken in zero-field-tooling (ZFC) and field-cooling (FC) conditions indicates three magnetic transitions at around 21, 49, and 210 K as well as the great irreversibility between ZFC and FC magnetization in the films. These anomalies are attributable to a magnetic-elastic coupling in the films. Magnetization measurements indicate ferromagnetic behaviour with hysteresis loops at 5 and 300 K for MnTe polycrystalline film. The coercivity ($H_c$) values at 5 and 300 K are 55 and 44 Oe, respectively. In electro-transport measurements, the temperature dependence of resistivity revealed a noticeable semiconducting behaviours and showed conduction via Mott variable range hopping at low temperatures.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.10
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• pp.656-663
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• 2012

After the construction of waterworks automatic meter reading with 15 mm diameter digital water mater with magnetoresistance sensor developed in this study at 96 households of apartment complexes located in Incheon-City B-Gu S-Dong, the feasibility of field application of waterworks automatic meter reading was evaluated. The field application of waterworks automatic meter reading was performed from July to December in 2011, and average reception rate was as low as 84.6% due to the instable wibro networks, the existence of communication blackout and temporary malfunction of router. After the extraction of 10 households with one to five residents out of 96 households by using stratified random sampling method and analysis of domestic water use, it was found that domestic water use was significant at August and showed a decreasing trend at September, followed by increase in domestic water use at November and decrease in domestic water use at December. This phenomenon should be attributed to weather factors (temperature, humidity, etc.), which significantly affected domestic water use. Similar trend in domestic water use in terms of weather factors was obtained in case of Liter per capita day of water use after the extraction of 30 households out of 96 households by using stratified random sampling method. After analysis of Liter per capita day for 96 households, single residents increases resulted in reduction of domestic water usage by about 14% of Liter per capita day. These results might be due to the fact that domestic water usage such as laundry, beverages, catering, cleaning, etc. should be required for even the household with one resident, whereas domestic water usage for those common utilization can be significantly saved for the household with more than one resident.

• Journal of the Korean Applied Science and Technology
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• v.37 no.1
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• pp.91-101
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• 2020

The purpose of this study was to investigate the influence of obesity on the expression of autophagy-related proteins in cardiac muscle. To this end, obesity was induced in rats through 20 weeks of high-fat diet, and the animals were then subjected to 8 weeks of treadmill exercise. Subsequently, the expression of proteins that regulate the induction of autophagy, formation of autophagosome, and fusion of autophagosome and lysosome was confirmed. Obesity was induced in the experimental animals (SD rats) through 20 weeks of high-fat diet (carbohydrate: 20%, fat: 60%, and protein: 20%), and they were subsequently subjected to 8 weeks of treadmill exercise (5 days/week, 30 min/day, 5 minutes; 8m/min, 5 minutes; 11m/min, 20 minutes; 14m/min). The experimental groups comprised the normal diet control group (ND-CON, n=10), high-fat diet comparison group (HFD-CON, n=10), and high-fat exercise group (HFD-TE, n=10). Oral glucose tolerance test was conducted before and after 8 weeks of treadmill exercise, and the area under the curve (AUC) was calculated. Through fasting insulin and fasting glucose levels, HOMA-IR, which is an index of insulin resistance, and abdominal visceral fat/body weight (AVF/BW) were calculated for comparison. Moreover, autophagy-related proteins were analyzed from cardiac tissue to investigate the effects of exercise training. Obesity was successfully induced in the HFD-CON group through long-term high-fat diet, and the HFD-CON group had higher body weight, AUC, HOMA-IR, and AVF/BW compared to the ND-CON group. The HFD-TE group, which underwent 8 weeks of treadmill exercise, showed improvements in AUC, HOMA-IR, and AVF/BW. Although the body weight tended to decrease as well, there was no statistically significant difference. mTOR and AMPK, which are involved in the induction of autophagy, both decreased in obesity but increased upon exercise. Beclin-1, BNIP3, ATG-7, p62, and LC3, which are related to the formation of autophagosomes, all increased in obesity and decreased after exercise. Cathepsin L and LAMP2, which regulate the fusion of autophagosome and lysosome, both decreased in obesity and increased upon exercise. Physical activity, including treadmill exercise, was found to induce normal autophagy and improve pathological phenomena observed in metabolic diseases. Therefore, the findings suggest the need to consider treadmill exercise as a primary means to achieve effective prevention and treatment of cardiac diseases.