• Proceedings of the Korean Magnestics Society Conference
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• 1999.10a
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• pp.36-37
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• 1999

• Journal of the Korean Magnetics Society
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• v.15 no.6
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• pp.320-324
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• 2005

The core loss of $3\%$ SiFe is strongly dependent on silicon content, impurities, permeability, and domain structure of the SiFe. Domain refining has been proved to be very good method for reduction of core loss in high permeability grain oriented SiFe, and laser scribing is well-blown as an effective and industrially important method of domain refinement. In this work, magnetic domain refinement has been carried out by using a pulsed Nd : YAG laser, and the core losses have been measured and analyzed to and optimal parameters of the laser treatment. The laser hem was focused with a spot size of $100{\mu}m$ and pulse energy of 10${\~}$35mJ and the lines were scribed with a period of ${\~}$5mm. The core loss was improved up to $17\%$ with 30 ns-Nd : YAG laser beam in $3\%$ SiFe.

• Journal of the Korean Magnetics Society
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• v.20 no.1
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• pp.1-7
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• 2010

We investigate the spin dynamics of the magnetic domain wall using the magnetic noise in the magnetic nanowire structure by employing micromagnetic simulations. Magnetic noise due to the thermal fluctuations in ferromagnetic materials is related to magnetic susceptibility and resonance frequency, which are important physical quantities in the study of the spin dynamics. In this study, we present the magnetic noise of the single domain without magnetic domain wall, and with the magnetic domain wall between two magnetic domains in ferromagnetic nanowires. It is confirmed that the Kittel equation with simple ellipsoid model with demagnetizing factor well describe the resonance frequency due to magnetic noise of the single domain. Besides, we find that there is a distinguishable additional resonance frequency, when a magnetic domain wall exists. It is verified that the additional resonance frequency is originated from the magnetic domain wall, and it is lower than one of the single domain. It implies that the spins inside the domain wall have a different effective field.

• KDI Journal of Economic Policy
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• v.26 no.1
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• pp.71-104
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• 2004

This paper explores the empirical performances of the workout companies with special interests in the effectiveness of corporate reorganizing tools on their revitalization. In the empirical analysis it considers the criteria of success or failure in restructuring from both creditors' and debtors' perspectives. The key results are summarized as follows. First, the initial conditions on the debt structure of the workout companies are significantly related to the revitalization from both creditors' and debtors' point of view. Second, the debt restructuring instruments are insignificant in the success of corporate turnarounds while the debt-to-equity conversion has been a relatively effective tool. Third, the self-restructuring efforts, employment downsizing and governance reshuffling do not affect the performances significantly. The higher importance of initial conditions than corporate restructuring efforts may imply that Korean corporate workouts serve better to the needs of creditor financial institutions which are to maximize debt recovery and of the government which is to overcome financial crisis.

• Journal of the Korean Magnetics Society
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• v.11 no.2
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• pp.63-71
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• 2001

The effects of an Ag seed layer on the magnetic properties and the microstructural evolution of SmCo/Cr thin films deposited on glass substrates were investigated. Coercivity of the films is 2.0 kOe when the thickness of Ag seed layer was 1nm thick, but it increased to 2.7 kOe when the Ag seed layer thickness is 3 nm. The increase of coercivity for film with 3 nm-thick Ag is due to roughness of Cr and grain size of Cr by the Ag microbumps. Ar partial pressure influenced on the formation of Ag microbumps, for example, they were formed at 5 mTorr when Ag thickness was 1 nm. The mechanism of magnetization reversal of the SmCo films changed from domain wall motion to domain rotation as the Ag inserted. This was thought to be due to inhibition of domain wall motion by the reduction of Cr grain size and the increase of roughness.

• Journal of the Korean Magnetics Society
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• v.8 no.4
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• pp.185-191
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• 1998

Magnetic domain structure and static magnetic properties were investigated in the ultra thin 3%Si-Fe strip wound cores when the strips were wound and annealed to relief the stress. The elastic and plastic deformation due to the radius of curvature was also investigated for the cores. At the as-wound state, the maze pattern domain structure was generated on the concave surface of the core and 180$^{\circ}$ domain wall was recovered by annealing 600 $^{\circ}C$$\times$30 min. After annealed by 900 $^{\circ}C$$\times$30 min, Hc of strip-wound cores was not reached to the $H_c$ of the strip even at the cores of elastic deformation region. It is necessary to relief the local stress remained in the core when the cores were manufactured for the application of ultra-thin 3%Si-Fe strip.

• Proceedings of the Korean Magnestics Society Conference
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• 2009.05a
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• pp.185-185
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• 2009

• Proceedings of the Korean Magnestics Society Conference
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• 2013.05a
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• pp.90-91
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• 2013

• Journal of the Korean Magnetics Society
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• v.20 no.2
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• pp.75-82
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• 2010

A recent progress on the prediction of the thermal stability of a nanostructured exchange-coupled trilayer is reviewed. An analytical/numerical combined method is used to calculate its magnetic energy barrier and hence the thermal stability parameter. An important feature of the method is the use of an analytical equation for the total energy that contains the magnetostatic fields. Under an assumption of the single domain state, the effective values of all the magnetostatic fields can be obtained by averaging their nonuniform values over the entire magnetic volume. In an equilibrium state, however, it is not easy to calculate the magnetostatic fields at the saddle point due to the absence of suitable methods of the accessing its magnetic configuration. This difficulty is overcome with the use of equations that link the magnetostatic fields at the saddle point and critical fields. Since the critical fields can readily be obtained by micromagnetic simulation, the present method should provide accurate results for the thermal stability of a nanostructured exchange-coupled trilayer.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.1
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• pp.88-98
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• 1994

A new neural network architecture called the Parallel. Self-Organizing Hierarchical Neural Network (PSHNN) is presented. The new architecture involves a number of stages in which each stage can be a particular neural network (SNN). The experiments performed in comparison to multi-layered network with backpropagation training and indicated the superiority of the new architecture in the sense of classification accuracy, training time,parallelism.