• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.1064-1066
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• 2004

This paper deals with analysis of a 3-phase high speed machine with diametrically magnetized rotor. The field equations due to magnet and stator windings are established in terms of vector potential and 2-d polar coordinate systems and then, characteristic equation of torque and back emf are derived by using field equations. Finally, this paper predicts open-circuit field, armature reaction field distributions, field distributions on load, torque and back emf distributions from those of equations. Results are compared with predictions from corresponding finite element analyses.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.450-451
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• 2007

Dot-patterned carbon nanotube (CNT) emitters with excellent field emission properties were fabricated using photosensitive CNT paste. We carried out a parametric study on the compositions and the fabrication processes of the paste, in particular, by ball milling CNTs, which were optimized in terms of dot shapes and their field emission characteristics. The ball milling process improved the field emission current of the dot-patterned CNT emitters several times higher than that of the non-milled paste.

• 한국해양공학회지
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• 제33권5호
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• pp.421-426
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• 2019

The directivity of an underwater sound source should be measured in an acoustically open field such as a calm sea or lake, or an anechoic water tank facility. However, technical difficulties arise when practically implementing this in open fields. Signal processing-based techniques such as a sound intensity method and near-field acoustic holography have been adopted to overcome the problem, but these are inefficient in terms of acquisition and maintenance costs. This study established a simple directivity estimation technique with data acquisition, filtering, and analysis tools. A numerical simulation based on an acoustic radiosity method showed that the technique is practicable for sound source directivity estimation in a diffused reverberant acoustic field like a reverberant water tank.

• Bulletin of the Korean Chemical Society
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• 제6권5호
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• pp.309-311
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• 1985

When a molecule is perturbed by an external field, the perturbed moecue can be described as a doubly perturbed system. Hartree-Fock operator in the absence of the field is the zeroth order Hamiltonian, and a correlation operator and the external field operator are perturbations. The effective Hamiltonian, which is a projection of the total Hamiltonian onto a small finite subspace (usually a valence space), has been formally derived. The influence of the external field to the molecular Hamiltonian itself has been examined within an effective Hamiltonian framework. The first order effective expectation values, for instance electromagnetic transition amplitudes, between valence states are found to be easily calculated - by simply taking matrix elements of the effective external field operator. Implications of the terms in perturbation expansion are discussed.

• Journal of applied mathematics & informatics
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• 제41권2호
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• pp.401-411
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• 2023

The effects of longitudinal velocity dusty fluid flow in a weak magnetic field are investigated in this paper. An external uniform magnetic field parallel to the flow of dusty fluid influences the flow of dusty fluid. Besides that, the problem under investigation is completely defined in terms of identifying parameters such as longitudinal velocity (u), Hartmann number (M), dust particle interactions β, stock resistance γ, Reynolds number (Re) and magnetic Reynolds number (Rm). While using suitable transformations of resemblance, The governing partial differential equations are transformed into a system of ordinary differential equations. The Hankel Transformation is used to solve these equations numerically. The effects of representing parameters on the fluid phase and particle phase velocity flow are investigated in this analysis. The magnitude of the fluid particle is reduced significantly. The result indicates the magnitude of the particle reduced significantly. Although some of our numerical solutions agree with some of the available results in the literature review, other results differs because of the effect of the introduced magnetic field.

• 대한가정학회지
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• 제38권5호
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• pp.1-14
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• 2000

The purpose of this study is to develop and evaluate a remarriage preparation program. Based on the system theory, strong family perspective, care & justice perspectives, and empirical research in this field,4 session remarriage preparation program is developed. Target population of this program is persons who remarry and persons who marry with remarried partner This program is evaluated in terms of the level of remarriage preparation and level of changing attitude after education in terms of self-esteem, cognition & knowledge of parent behavior in the remarried family, object evaluation of their future remarriage life. Future research, theoretical and practical implications are added.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1794-1798
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• 2008

Inside noise level of a running train in open field is the summation of air borne noise and structure-borne noise. Anti-roll bar is the major transmission path of vibration from bogie. And this vibration gives an effect to the structure borne noise. In this paper, the effect of anti-roll bar is investigated. Structure borne noise is analyzed in terms of changing the mounting position of anti-roll bar to reduce inside noise levels.

• 충청수학회지
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• 제37권2호
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• pp.67-74
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• 2024

Maximal surfaces have a prominent place in the field of differential geometry, captivating researchers with their intriguing properties. Bearing a direct analogy to the minimal surfaces in Euclidean space, investigating both their similarities and differences has long been an important issue. This paper is aimed to give a local characterization of maximal surfaces in 𝕃³ in terms of their geodesic curvatures, which is analogous to the minimal surface case presented in [8]. We present a classification of the maximal surfaces under some simple condition on the geodesic curvatures of the parameter curves in the line of curvature coordinates.

• 한국융합학회논문지
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• 제6권1호
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• pp.49-55
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• 2015

FTA(Free Trade Agreement) 환경에서 수출입 기업이 무관세 혜택을 받기위해서는 원산지 규정을 준수하는 일이고, 이를 위해 가장 먼저 선행되어야하는 것이 물품의 품목분류가 필요하다. 이를 위해서는 관세율표를 구성하고 있는 HS(Harmonized System) 품목분류의 기본원리에 대한 철저한 이해가 전제되어야하며, 품목에 대한 호(Heading)에서의 상품명에 대한 이해와 관련 영역(section)이나 해당 영역(chapter)의 주(Note)는 물론 해설서의 규정까지 이해하고 있어야 올바른 품목분류를 할 수 있다. 이러한 문제점을 해결하기 위해 본 논문은 물품의 특성을 잘 알고 있는 경우, 업무 담당자도 쉽고 정확하게 분류할 수 있도록 품목분류의 결정에 영향을 줄 수 있는 7가지 결정요소를 시스템에서 먼저 제시하여 사용자가 선택하도록 하고, 각 산업에서 통상적으로 통용되는 현장용어 지식을 포함하는 융합적 수행시스템 기반의 HS 품목분류 서비스 개발을 제안하였다. 마지막으로 이 시스템의 실제 기업 현장 적용을 통해 효과를 검토하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제33권2호
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• pp.245-253
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• 2020

Objective: To develop the fermentation quality and chemical composition of alfalfa (Medicago sativa Lam.) silage, plants were inoculated with different lactic acid bacteria (LAB) strains at field 24 hours before harvest. Methods: The treatment groups were as follow: silage without additive as a control and inoculated with each strains of Lactobacillus brevis (LS-55-2-2), Leuconostoc citerum (L. citerum; L-70-6-1), Lactobacillus bifermentans (L. bifermentans; LS-65-2-1), Lactobacillus plantarum (L. plantarum; LS-3-3) and L. plantarum (LS-72-2). All the silages were stored at 25℃. Parameters such as pH, microorganism and volatile fatty acid contents, crude protein, neutral detergent fiber, acid detergent fiber, net gas, metabolizable energy, organic matter digestibility, dry matter intake and relative feed value were measured to determine fermentation quality, chemical compositions and relative feed value of alfalfa silages. Results: Significant differences were found among the control and treated groups in terms of pH and microorganism contents at all opening times and crude protein, net gas, metabolizable energy and organic matter digestibility of final silage. The pH values ranged from 4.70 to 5.52 for all treatments and control silage had the highest value of overall treatments at T₇₅d silages. Volatile fatty acid of silages was not influenced significantly by inoculations. However, lactic acid content of L. bifermentans (LS-65-2-1) was higher than the other treatments. The highest metabolizable energy and organic matter digestibility were recorded from L. citerum (L-70-6-1) inoculation. In addition, no significant differences were found among treatments in terms of neutral detergent fiber, acid detergent fiber, dry matter intake and relative feed value. Conclusion: Among the treated LAB isolates, L. bifermentans came into prominence especially in terms of organic acid composition and quality characters of silages.