• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1017-1018
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• 2011

This paper deals with a magnetic field analysis on brushless DC(BLDC) motor with radial magnetization permanent magnet. In order to analyze the magnetic field, multi-layer analysis based on space harmonics method is employed. Finally, the analytical results are validated by non-linear Finite Element Analysis(FEA).

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.12
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• pp.789-796
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• 2000

This paper deals with magnetic field and characteristic analysis for ring type slotless synchronous motors by using analytical method. Since magnetic air-gap in the slotless motors is much larger than mechanical air-gap, it is necessary to analyze the magnetic flux distribution at the whole magnetic airgap region. therefore, this paper analyzes the duplicated magnetic field derived by both Permanent Magnet(PM) and armature current and estimates the back electromotive force and torque characteristic by subdividing the conductor region. The analysis results are verified by comparing with Finite Element Analysis(FEA) results.

• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.119-122
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• 2002

This paper presents detailed characteristic of a Reluctance Synchronous Motor(RSM) which has a transverse-laminated rotor. First of all, the analysis of a magnetic circuit field between stator and rotor should be achieved in order to predict the performance characteristic of the RSM. For the analysis of a magnetic circuit field, the Finite Element(FE) analysis and a experimental method are used. The analytical result of the inductance flux distribution, vector potential, and the output shows some good characteristic along with the load condition.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.35-37
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• 2009

This paper deals with the static analysis on the permanent magnet synchronous motors(PMSM) using transfer relation theorem according to the shaft materials, and adopts the analytical method to predict the magnetic field distribution and to calculate the electrical parameters by using Transfer Relation Theorem(TRT) in terms of 2-D model in polar coordinates system. In addition, the three types of PMSMS with different types of shafts, which are Iron cored, Air cored, Full-ring permanent magnet type shaft, are suggested in this research, and with those models, not only the analysis on the magnetic field distribution, the estimation of electrical parameters, but also their comparison with Finite Element Analysis(FEA) is processed.

• Analytical Science and Technology
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• v.25 no.6
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• pp.370-374
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• 2012

As for quality evaluation of paper records, it is very important to measure acidity and moisture in paper. In the case important paper records, it should be measured directly in field. But ISO standard analytical method would be limited to measure directly in field for quality evaluation of paper records until now. Therefore it could be to use mobile small NIR spectrometer for being analyzed by direct and non-invasive method in field. The wavelength range of small spectrometer has from 900 to 1700 nm, and the surface of paper could be measured by diffused reflected optical fiber probe. Thus, the acidity and moisture could be analyzed on the paper record with from 1970 to 2003. As the result, it could be confirmed to have each more than 0.9 as the correlation of acidity and moisture. Thus, it will be possible to develope the evaluation system of paper record with mobile small NIR spectrometer and optical fiber by the result.

• The Korean Journal of Pesticide Science
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• v.10 no.2
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• pp.84-90
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• 2006

In the field of agriculture, FT-NIR mainly has been used in qualitative management of produces without sample preparation with a data set built from a quantitative value of sample components confirmed by another analytical instrument. On the other hand, inert materials of crop protection products nearly haven't examined instrumental analysis because of analytical problems of high-molecular inert materials and a variety of formulation type. This study, results make it possible to solve an analytical problems of crop protection products using FT-NIR chemometrics technique from spectrum calculator module.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.696-698
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• 2001

This paper considers the research of the hybrid interrupter which adopts both rotating arc and thermal expansion technology. The operating principle of this device depends on rapid arc rotation due to the magnetic field created by the fault current through a coil which is mounted on contacts and also relies on the principle of thermal expansion created by arc energy in extinguishing chamber and finally causes pressure rise in expansion volume. To develope this type of interrupter, we introduced analytical analysis including electromagnetic and arc fluid simulation and experimental analysis including construction of current source generation facility and arc behavior measurements. In this research, the principle of the interrupting techniques are given and analytical and experimental results of hybrid interrupter which is developed by new technology is introduced.

• Structural Engineering and Mechanics
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• v.75 no.2
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• pp.157-174
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• 2020

In the present paper, a simple analytical model is developed based on a new refined parabolic shear deformation theory (RPSDT) for free vibration and buckling analysis of orthotropic rectangular plates with simply supported boundary conditions. The displacement field is simpler than those of other higher-order theories since it is modeled with only two unknowns and accounts for a parabolic distribution of the transverse shear stress through the plate thickness. The governing differential equations related to the present theory are obtained from the principle of virtual work, while the solution of the eigenvalue problem is achieved by assuming a Navier technique in the form of a double trigonometric series that satisfy the edge boundary conditions of the plate. Numerical results are presented and compared with previously published results for orthotropic rectangular plates in order to verify the precision of the proposed analytical model and to assess the impacts of several parameters such as the modulus ratio, the side-to-thickness ratio and the geometric ratio on natural frequencies and critical buckling loads. From these results, it can be concluded that the present computations are in excellent agreement with the other higher-order theories.

• Geomechanics and Engineering
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• v.35 no.6
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• pp.593-601
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• 2023

In this paper, an analytical solution of large-strain cylindrical cavity expansion in compaction grouting problem under temperature field is given. Considering the stress increment caused by temperature, the analytical solution of cavity expansion under traditional isothermal conditions is improved by substituting the temperature stress increment into the cavity expansion analysis. Subsequently, combined with the first law of thermodynamics, the energy theory is also introduced into the cylindrical cavity expansion analysis, and the energy dissipation solution of cylindrical cavity expansion is derived. Finally, the validity and reliability of solution are proved by comparing the results of expansion pressure with those in published literatures. The results show that the dimensionless expansion pressure increases with the increase of temperature, and the thermal response increases with the increase of dilation angle. The higher the exothermic temperature of grouting slurry, the greater the plastic deformation energy of the surrounding soil, that is, the greater the influence on the surrounding soil deformation and the surrounding environment. The proposed solution not only enrich the theoretical system of cavity expansion, but also can be used as a theoretical tool for energy geotechnical engineering problems, such as CPT, nuclear waste disposal, energy pile and chemical grouting, etc.

• Analytical Science and Technology
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• v.37 no.4
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• pp.230-238
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• 2024

This study evaluates a method for quantifying selenium (Se) concentration in soil using inductively coupled plasma mass spectrometry (ICP-MS), with oxygen as a reaction gas. This approach addresses the challenge of detecting low levels of Se in complex soil matrices and aims to effectively minimize interference problems typically associated with argon plasma in traditional ICP-MS analyses. The analytical method utilizes conditions optimized for minimizing spectral interference and were validated by linearity, accuracy, precision, limit of detection (LOD), and limit of quantification (LOQ). The method demonstrated good linearity, high accuracy (90-97 %), and remarkable sensitivity, achieving detection and quantification limits of 0.15 ㎍/kg and 0.44 ㎍/kg, respectively. Developed analysis method for Se in soil was applied to field samples in the different regions of South Korea and Se concentration ranged from 0.11 to 0.52 mg/kg. Correlation analysis between Se concentration and soil properties showed that Se concentration was significantly correlated with cation exchange capacity (CEC) and available phosphorus among other soil properties.