• Korean Journal of Materials Research
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• v.18 no.3
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• pp.153-158
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• 2008

Fe-aluminides have the potential to replace many types of stainless steels that are currently used in structural applications. Once commercialized, it is expected that they will be twice as strong as stainless steels with higher corrosion resistance at high temperatures, while their average production cost will be approximately 10% of that of stainless steels. Self-propagating, high-temperature Synthesis (SHS) has been used to produce intermetallic and ceramic compounds from reactions between elemental constituents. The driving force for the SHS is the high thermodynamic stability during the formation of the intermetallic compound. Therefore, the advantages of the SHS method include a higher purity of the products, low energy requirements and the relative simplicity of the process. In this work, a Fe-aluminide intermetallic compound was formed from high-purity elemental Fe and Al foils via a SHS reaction in a hot press. The formation of iron aluminides at the interface between the Fe and Al foil was observed to be controlled by the temperature, pressure and heating rate. Particularly, the heating rate plays the most important role in the formation of the intermetallic compound during the SHS reaction. According to a DSC analysis, a SHS reaction appeared at two different temperatures below and above the metaling point of Al. It was also observed that the SHS reaction temperatures increased as the heating rate increased. A fully dense, well-bonded intermetallic composite sheet with a thickness of $700\;{\mu}m$ was formed by a heat treatment at $665^{\circ}C$ for 15 hours after a SHS reaction of alternatively layered 10 Fe and 9 Al foils. The phases and microstructures of the intermetallic composite sheets were confirmed by EPMA and XRD analyses.

• Journal of Magnetics
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• v.7 no.2
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• pp.45-50
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• 2002

A magnetic field annealing is firstly used for nanostructured Sm-Co/Co films, prepared by magnetron sputtering method. The effects of magnetic field annealing on single-layered Sm-Co films are different from those on multi-layered Sm-Co/Co films. A detailed analysis of microstructures and magnetic properties is made by means of HRTEM, Auger electron spectroscopy, XRD and Physical Property Measurement System (PPMS). From magnetic properties and microstructure analysis, it was confirmed that these differences originate from the effects of magnetic field annealing on crystallization behavior of the films. The relationship between magnetic properties and microstructures explains a different demagnetization process of single-layered and multilayered films. For the single-layered Sm-Co films, magnetic-field-annealing makes the main phases change from $CaCu_5/ to Zn_2Th_{17}$ structure, resulting in a decrease of coercivity. The results show that the magnetic-field-annealing is useful to improve the properties of nanostructured Sm-Co(30 nm)/Co(10 nm) films, which ascribe to improving the pinning effectiveness in coercivity mechanism and decreasing the magnetostatic interaction of films. A very high coercivity about 0.7 T was obtained from nanoscaled multi-layered Sm-Co(30 nm)-/Co(10 nm) films.

• Vacuum Magazine
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• v.2 no.2
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• pp.4-11
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• 2015

During last two decades, remarkable progresses have been made in organic electronic devices, such as organic light-emitting device, organic photovoltaic and many other applied devices. Many of these progress are attributed to the multilayered/heterojunction device architectures, which could be achieved from the control of "interfacial energetics". In that sense, the interfacial electronic structures in organic electronic devices have a decisive role in device performance. However, the prediction of the interfacial electronic structures from each separate material is not trivial. Many complex phenomena occur at the interface and these can be only understood from thorough measurements on interfacial electronic structures in situ. Photoemission and inverse photoemission spectroscopy have been known as the most proper measurement tools to analyze these interfacial electronic structures. In this review, the basic principles of (inverse) photoemission spectroscopy and typical measurement results on organic/inorganic interfaces are introduced.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.7
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• pp.1065-1073
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• 1999

This paper analyzed the ground bounce caused by the power plane resonance in the multilayered printed circuit board(PCB) using the Haar-wavelet-based Multiresolution Time-Domain (MRTD). In conventional Finite-Difference Time-Domain(FDTD), the highly fine vertical cell is needed to represent the distance between $V_{cc}$ plane and ground plane since the two planes are very close. Therefore the time step $\Deltat$ must be very small to satisfy the stability condition. As a result, a large number of iterations are needed to obtain the response in wanted time. For this problem, this paper showed that the computation time can be reduced by application of the MRTD method. The results obtained by the MRTD agree very well with those by FDTD method and analytic solutions. In conclusion, this paper proved the efficiency and accuracy of MRTD method for analyzing the EMI/EMC problems in PCB.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.1119-1122
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• 2005

This paper describes the implementation methods of the MLP (mulilayer perteptrons) recognizers for numerals and non-nummerals. The MLP has known to be a very efficient classifier to recognize handwritten numerals in terms of recognition accuracy, speed, and memory requirements. The MLP in the previous researches, however, focuses on the only numeral inputs and does not pay attention to non-numeral inputs with respect to recognition accuracy, rejection rates, and other characteristics. In this paper, we present some implementation methods of the MLP in the environments that numeral and non-numerals are mixed. The MLP had been developed by three methods, and investigated with three error types introduced. The experiments had been conducted on a total of about 63,000 numerals and non-numerals. The promising method to recognize numeral and non-numerals is described in terms of the three error types.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.4
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• pp.302-307
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• 2007

In this paper, a flap valve micropump with an ionic polymer-metal composite (IPMC) actuator was designed, fabricated, and experimentally characterized. A multilayered IPMC based on Nafion/layered silicate and Nafion/silica nanocomposites was fabricated for the actuation section of the micropump. The IPMC diaphragm, a key element of the mircopump, was designed so that the IPMC actuator was supported by a flexible polydimethylsiloxane (PDMS) structure at its perimeter. This design feature enabled a significantly high displacement of the IPMC diaphragm. The overall size of the micropump is $20{\times}20{\times}5$ ${mm}^3$. Water flow rates of up to 760 ${\mu}l$/min and a maximum backpressure of 1.5 kPa were recorded. A significant advantage of the proposed micropump is its low driven voltage from only 1-3 V. In addition, a simple and effective design, and an ease of manufacturing are other advantages of the present micropump.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.162-162
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• 2000

We have studied magnetic properties of Co/Pt multilayered films which have attracted great interest as high-density magneto-optical (MO) recording media due to their good MO properties. For this study, [Pt(45 )/Co(35 )]$\times$8 films were deposited with a Pt buffer layer of 60 on Si(100) substrate by alternating electron-beam evaporation in a high vacuum and were ion beam mixed by using 80keV Ar+ at 25$0^{\circ}C$. Especially, an external magnetic field was added to help changing magnetic property during ion beam mixing (IBM). The intermixing of Co and Pt layers after IBM was confirmed with Rutherford Backscattering Spectroscopy (RBS) and Transmission Electron Microscopy (TEM). The MO property of the film was measured with magneto-optical Kerr spectrometer and the change of magnetic easy axis in the film plane was observed from Ker loop data. This anomalous result might be correlated with the change of atomic structure due to the intermixing effect.

• Food Engineering Progress
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• v.14 no.1
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• pp.27-34
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• 2010

Multilayer edible coatings was applied to lemon with beeswax-hydroxypropyl methylcellulose (BW-HPMC), soybean oil-carboxymethyl cellulose (SBO-CMC), and carnaubawax-shellac-locust bean gum (CW-SL-LBG), respectively. The multilayer was composed of two layers of the same material, but the outer layer only contained vitamins C and E as antioxidants. Coating amounts built on lemon peel were measured to be large in the order of CW-SLLBG> BW-HPMC> SBO-CMC. The coated lemons were stored at 30${^{\circ}C}$ for 12 days. CW-SL-LBG showed the least change during the storage in weight loss, rotten rate, firmness, and browning. Whereas SBO-CMC had the least change in pH, soluble solid amount, and titratable acidity. In a sensory test, CW-SL-LBG was evaluated to be the best in the attributes such as spoilage, glossiness, color, firmness, and flavor. Overall CW-SL-LBG was judged to be the best for multilayerd coating with vitamin C and E on lemon.

• Journal of the Korean Magnetics Society
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• v.4 no.1
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• pp.20-24
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• 1994

The read/write characteristics of CoCr/NiFe double layered media are strongly affected by the magnetic properties of NiFe magnetic soft layer as well as those of CoCr recording layer. Modification of the permalloy layer by NiFe/Ge multilayer scheme resulted in the higher recording sensitivity and the higher reproduced voltage of CoCr/NiFe medium and this is attributed to the higher permeability of the back layer and high perpendicular anisotropy of the CoCr recording layer. Although higher permeability of back layer results in higher recording sensitivity, the increment of the reproduced voltage was not remarkable, which can be confirmed in the FEM numerical analysis. On the contrary, peak shift characteristics of the CoCr/NiFe medium with the NiFe multi back layer was deteriorated compared to that of the CoCr/NiFe medium with NiFe single back layer. Insertion of ferromagnetic thin CoZrNb intermediate layer between CoCr and NiFe layer was effective to ensure large reproduced voltage and low peak shift. These recoridng characteristics were also discussed in connection with microstructural characteristics.

• Journal of the Economic Geographical Society of Korea
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• v.21 no.4
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• pp.393-408
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• 2018

This study aims to raise our understanding of how memory of a social group is transnationally appropriated and utilized by other subjects. A collective sense of justice for comfort women has been handed to many Koreans either in Korea or in overseas countries since the early 1990s. In the U.S., the first comfort women monument was established in Palisades Park, New Jersey by Korean-Americans and local politicians as they wanted to strengthen the common sense of Korean ethnicity with the symbolic power of the memoryscape. Exploring the diffusion of comfort women memorials in the U.S., this study examines the complexity and multilayered structure of memory politics and its transnational mobility, which are connected to Korean-Americans' struggle for belonging.