• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.8
• /
• pp.1080-1089
• /
• 2013

Interior Permanent Magnet Synchronous Machines (IPMSMs) with rare earth magnet are widely used in electric vehicles and hybrid electric vehicles. IPMSMs having high efficiency, high torque, and a wide speed range are employed in propulsion system. And the rotor in an IPMSM is generally made of a rare earth magnet to achieve a large energy product and high torque. This paper discusses issues regarding design and performance of IPMSMs using different factors of BH magnetic characteristic. It is necessary to choose factors of magnetic material according to permanent magnet shape in rotor for high performance. Response Surface Methodology (RSM) is selected to obtain factors of magnetic material according to variety of rotor shapes. The RSM is a collection of mathematical and statistical techniques useful for the analysis of problems in which a response of interest in influenced by several variables and the objective is to optimize response. Therefore, it is necessary to analyze the torque characteristics of an IPMSM having magnet BH hysteresis curve with different rotor shape. Factors of residual flux density (Br) factor and intrinsic coercive force (Hc) are important parameters in RSM for rotor shape. The rotor shapes for IPMSMs having magnet BH characteristic were investigated using the RSM, and three shapes were analyzed in detail using FEA. The results lead to design consequence of IPMSMs in the various rare earth magnet materials.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.19 no.2
• /
• pp.4417-4422
• /
• 1977

This thesis is a result of theoretical and electrical experimental studies for the shape of Seepage on various Earth Dams. The decrement method of seepage through of water amount to earth Dam's was tested by means of experiment by the model constructed in the water tank. A study of the seepage through earth Dam's is necessary for a satisfactory of the same. An attempt was made in these investigations to study the problem of the seepage through homogeneous earth dams with filters located near the axis of the dam and filters extending in to upstream portion of the dam by the electrical analogy method. The experimental results were at variance with the graphical solution given by A Casagrande method. Some of the results were checked by relaxation method and by the circle criterion for drawing flow nets.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.23 no.1
• /
• pp.34-40
• /
• 2009

After a research on appearance diagnosis and fish, bird, horse, and turtle types, this study concluded as following. Appearance diagnosis is a technique that exams five jang organs by color and shape of eye, nose, mouth, and ear. Four HyungSang types-including fish, bird, horse and turtle types-are evaluated upon the external shape that are created while type of seed changes. Appearance diagnosis focuses on five jang organs. Four HyungSang types focus on external shape, but are eventually related to five jang organs. Thus, two different techniques possess a point in common; five jang organs. The assignment of nose, eye, ear and mouth to the Five elements varies between two techniques. On the viewpoint of formation, appearance diagnosis assigns them to metal-water-wood-fire-earth and movement, and four HyungSang types do to wood-fire-earth-metal-water and constitution. On the viewpoint of body/use and static/dynamic, appearance diagnosis assigns them to metal-water-wood-fire-earth and constitution, and four HyungSang types do to wood-fire-earth-metal-water and movement. If nose, eye, ear, and mouth are assigned by on four HyungSang types, which are based on external shape, the assignment can be utilized in diagnosis. If, however, they are assigned by appearance diagnosis, it can be focus on treatment. Five jang organs and six fu organs are affected by internal conditions because they are located inside of human body, while four HyungSang types are affected by external conditions because it deals with external shape. If a disease occurs in the developed part of the body, it would be difficult to be cured because four HyungSang types depend on external shapes.

• Geomechanics and Engineering
• /
• v.18 no.3
• /
• pp.247-258
• /
• 2019

Soil strength and failure surface geometry directly influence magnitudes of passive earth thrust acting on geotechnical retaining structures. Accordingly, it is expected that as long as the shape of the failure surface geometry and strength parameters of the backfill are known, magnitudes of computed passive earth thrusts should be highly accurate. Building on this premise, this study adopts conventional method of slices for calculating passive earth thrust and combines it with equations for estimating failure surface geometries based on in-situ stress state and density. Accuracy of the proposed method is checked using the results obtained from small-scale physical retaining wall model tests. In these model tests, backfill was prepared using either air pluviation or compaction and different backfill relative densities were used in each test. When the calculated passive earth thrust magnitudes were compared with the measured values, it was noticed that the results were highly compatible for the tests with pluviated backfills. On the other hand, calculated thrust magnitudes significantly underestimated the measured thrust magnitudes for those tests with compacted backfills. Based on this observation, a new approach for the calculation of passive earth pressures is developed. The proposed approach calculates the magnitude and considers the influence of locked-in stresses that are the by-products of the backfill preparation method in the computation of lateral earth forces. Finally, recommendations are given for any geotechnical application involving the compaction of granular bodies that are equally applicable to physical modelling studies and field construction problems.

• Journal of the Korean earth science society
• /
• v.28 no.6
• /
• pp.655-672
• /
• 2007

The purpose of this study was to investigate information sources and types of reasoning that non-astronomy major undergraduate students used to build their mental models on the mechanism of the Moon craters formation. In-depth interview was used to collect qualitative data, and the questions for the interview were developed through an analytical induction method. We interviewed four students individually by using Seidman's interview step. The findings revealed that the participants built nonscientific mental models, and yet they held a consistent explanatory framework. The students explained that the crater was made by the fall of a meteorite. They all suggested a similar shape of meteorite even though their drawings about the shape of craters and its related to variables were different from one another. The information sources that the participants used fur their explanatory frameworks were varied, i.e., daily experiences, subject knowledges, and intuition. In addition, they used causal reasoning, intuitional reasoning, knowledge based reasoning, and analogical reasoning.

• Journal of architectural history
• /
• v.2 no.2 s.4
• /
• pp.89-106
• /
• 1993

Wherever Buddhism has flourished, there were stupas in the form of monuments which have their origin in the tumulm of prehistoric times. After the death of Buddha, his body was cremated following the Indian funeral custom. His ashes, which long reserved for the remains of nobles and holymen, were enshrined under such artificial hills of earth and brick. The Stupa was in origin a simple burial-mound. The form of the burial-mound was a symbolical or magic reconstruction of the imagined shape of the sky, like a dome covering the earth. The domical form of the earliest tumuli may have been concious replicas of the shape of the Vedic hut. There are relationships which may have originally existed between the stupa and West Asiatic monuments. Buddhist Stupa originally cosisted of an almost hemispherical tumulus(anda) and an altar-like structure (harmika) on its top, surmounted by one or several superimposed honorific umbrellas (hti, catta). This hemispherical form is associated with centralisation, lunar worship, mother earth, and Siva. Anda means a symbol of latent creative power, the harmika symbolizes the sanctuary enthroned aboved the world. The honorific umbrella, as an abstract imitation of the shade-giving tree is one of the chief solar symbols and that of enlightenment.

• Korean Journal of Environmental Biology
• /
• v.40 no.4
• /
• pp.497-509
• /
• 2022

A strain of Amphidinium species was established from samples collected from the intertidal zone of a sandy beach of Jeju Island, Korea. Its cells were 13.0-15.0 ㎛ in length and 10.0-13.0 ㎛ in width. Its cell shape was round or oval and dorsoventrally flat. A pyrenoid was located in the center of the cell and a nucleus was posteriorly located. Its epicone was small and left-deflecting. Its cingulum had V-shape on the ventral side, forming a ventral ridge and extending to the sulcus. Polygonal amphiesmal vesicles and ring-shaped body scales not described previous were observed on the surface of the cell. Its morphological features were consistent with those of previously described Amphidinium fijiense. Phylogeny based on ITS region and LSU rDNA sequences revealed that this Amphidinium isolate was clearly clustered with other A. fijiense strains, but separated from other Amphidinium species. These results indicate that this Amphidinium isolate is A. fijiense. This study reports its presence for the first time in the intertidal zone of a sandy beach of Jeju Island, Korea.

• Journal of Astronomy and Space Sciences
• /
• v.13 no.1
• /
• pp.19-31
• /
• 1996

We have analyzed collected photoelectric light curves for light variations of SW Lac. The method of Fourier analysis was adopted to quantify the light variation from season to season. We found the linear relation between the Fourier coefficient, B1 and the magnitude difference between two maxima. The total light of the system has been decreased as much as 0m.04 during approxiamately 20 years time interval. Photoelectric parameters including spot parameters for all light curves were obtained by the method of the Wilson and Devinney differential correction in order to secure the variations of parameters from season to season. SW Lac, not like RS CVn type stars, required to adjust all parameters as well as spot parameters for a reasonable fit to the observations of each epoch. A surface temperature of cooler star is one of the most sensitive parameters to affect a shape of light curve of SW Lac. We conclude that the shape of light curve of SW Lac varies even during one season as well as season to season. The light curve is mainly caused by inhomogeneous surface temperature due to strong chromospheric activity of the system.

• Economic and Environmental Geology
• /
• v.56 no.3
• /
• pp.293-300
• /
• 2023

The Shape Preferred Orientation (SPO) method has been used to analyze the orientation of fault motion, which is utilized as basic data for fault kinematics studies. The rigid grains, which as quartz, feldspar, and rock fragments, in the fault gouge are arranged in the P-shear direction through rigid body rotation by a given shear stress. Using this characteristic, the fault motion can be estimated from the SPO inversely. Recently, a method for securing precision and reliability by measuring 3D-SPO using X-ray CT images and examining the shape of a large number of particles in a short time has been developed. As a result, the SPO method analyzes the orientation of thousands to tens of thousands of particles at high speed, suggests the direction of fault motion, and provides easy accessibility and reliable data. In addition, the shape information and orientation distribution data of particles, which are by-products obtained in the SPO analysis process, are expected to be used as basic data for conducting various studies such as the local deformation of fault rocks and the fault generation mechanism.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2004.05a
• /
• pp.48-52
• /
• 2004

Recently, there are many electricity, electronics, and communication equipment which need to earthing in the building. When electric current flows into a certain earthing system in the same building, the potential of other earthing system rises. This potential interference repuire surface potential of electrodes by electrode shape. In this paper basic formula is deduced on the basis of both electrodes surface potential of earth electrode as a source of the potential interference and earth electrode which receive the potential interference. The degree of potential interference as multiple earth electrode is verified the simulated results by means of the simple model in advance.