• 전기의세계
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• 제28권3호
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• pp.72-77
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• 1979

The object of this paper is to try to develope Tulular Liner Induction Motor which consists of primary stator that generates traveling magnetic field from the three-phase winding of formed-wound concentric coil, and try to identify the characteristics of starting force. To indentify the theoretical starting force formular we have quoted the conventional Maxwell's basic equation and Poisson's equation which are used in the general machines thereby having obtained the formular of the current with in the conductor and of the air gap magnetic field respectively. General starting force formular is acquired by applying the formular of the current and magnetic field which was theoretically derived above. To this theoretically starting force formula various constants and the values of magnetic flux density resulting from the experimental motor are applied to present theoretically calculated values. Comparing these theoretically caculated values experimentally weighed values, we have proved the validity of theoretical research.

• 한국정밀공학회지
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• 제22권7호
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• pp.102-111
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• 2005

In this paper, we address a position control for a parallel stage, which is levitated and driven by electric magnetic force. This consists of a levitating object (called platen) with 4 permanent magnetic linear synchronous motors in parallel. Each motor generates vertical force for suspension against gravity and propulsion force horizontally as well. This stage can generate six degrees of freedom motion by the vertical and horizontal force. A dynamic equation of the stage system is derived based on Newton-Euler method and it's special Jacobian matrix describing a relation between the limited velocity and Cartesian velocity is done. There are proposed two control methods for positioning which are Cartesian space controller and Actuator space controller. The control performance of the Cartesian space controller is better than the Actuator space controller in task space trajectory while the Actuator space controller is simpler than the Cartesian space controller in controller realization.

• 한국초등과학교육학회지:초등과학교육
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• 제23권2호
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• pp.141-151
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• 2004

Pre-service teachers' understandings on magnet was investigated through the questionnaire method. The questionnaire was composed of 17 questions about the strength of magnet, the magnetized object and the direction of magnetic field around magnet. In this investigation study, 225 pre-service teachers were selected through random sampling method, who were sophomores in a National University of Education. The formation rate of the scientific conceptions on the strength of magnet was 30.3% and that on the direction of magnetic field around magnet was 53.9%. The average formation rate of scientific conception of all questions on magnet was 44.13%, which doesn't seem to be high as expected. It shows that many of subjects of the questionnaire don't understand fully the concept of moleclar magnet model and the superposition effects of magnetic field around magnet. The formation rate of the scientific conception on magnet of females who took courses in sciences in high school were higher than that of females who took courses in arts in high school, which had meaningful difference (p<.05).

• 지구물리와물리탐사
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• 제25권2호
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• pp.85-92
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• 2022

한쪽 방향으로 연장된 이상체를 멀리 떨어져서 관측하면 선형 이상체로 근사가 가능하다. 이런 경우 자력 및 자력 변화율 텐서를 적용하기 위해서는 선형 이상체에 대한 해석해가 필요하다. 따라서 이 논문에서는 선형 이상체에 대한 자력과 자력 변화율 텐서 반응식을 유도하였다. 벡터 자력은 기존에 유도한 선형 이상체에 대한 중력 변화율 텐서를 포아송 관계식을 이용하여 벡터 자력으로 변환하여 유도하였다. 자력 변화율 텐서는 벡터 자력를 기준 직교 좌표계의 성분으로 한번 더 미분하여 유도하였다. 시추공에서 얻은 총자력 탐사 자료를 가정하고, 선형 이상체의 길이, 방향, 자력 모멘트를 비선형 역산 방법으로 추정하는 사례를 보여주었다.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2003년도 한국우주과학회보 제12권2호
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• pp.63-63
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• 2003

There are many actuators and sensors used for attitude control system for KOMPSAT such as Reaction Wheel Assembly, Magnetic Torque Assembly, Dual Thruster Module, Solar array Drive, Three Axis Magnetometer, Conical Earth Sensor, Fine Sun Sensor Assembly, Coarse Sun Sensor Assembly, Gyro Reference Assembly and so on. For KOMPSA T satellite it has been considered using the Magnetic Torquer (MTQ) generating the magnetic dipole moment. In general, the magnetic dipole moment for satellite attitude control system is used for dumping out the excessive reaction wheel momentum so that the reaction wheel speed is not saturated. The objective of this study is to analyze the magnetic field characteristics generated by the Magnetic Torquer using the Maxwell 2D Field Simulator software. Currently, the developing model (DM) of the MTQ is being developed and manufactured at a company under the supervision of KARL MTQ is an electromagnet consisting of a ferromagnetic cylindrical core on which an excitation coil is wound. A current is passed through the coil to produce a dipole momentum in the ferromagnetic core. The configuration of the MTQ will be introduced in the presentation. The 2 dimensional model of the MTQ is drawn as axisymmetric models in RZ plane, and each corresponding material is assigned to the each MTQ object, the core, coil, and background. After the boundary conditions, current sources, and solution parameters are set up, the magnetic field intensities, directions, and other values specified by users can be calculated by using the finite element analysis. The theoretical magnetic field quantities obtained by the Maxwell 2D Simulator can be used for the basis of the development of the MTQ.

• 제어로봇시스템학회논문지
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• 제6권6호
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• pp.454-461
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• 2000

Electrostatic suspension offers an advantage of directly suspending various materials such as conductive materials, semiconductors and dielectric materials without any mechanical contacts. This is a specific feature compared with electromagnetic suspension which can suspend only ferro-magnetic material. In general, the electrostatic suspension systems require position sensors for stabilizing the suspended object. Therefore, a lot of displacement sensors and a switching circuit are required for moving the object through a long distance. In order to circumvent this problem, this paper proposes a self-sensing method which can provide the gap displacement between electrodes and suspended object without external sensors. Moreover a simple on-off controller is presented for stabilization. Experimental validation of the proposed scheme has been performed through the successful levitation of a 4-inch silicon wafer.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2007년도 추계 학술대회논문집
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• pp.67-72
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• 2007

A post-processing program based on the OOP(Object-Oriented Programming) concept has been developed for visualization of MRI. User-friendly GUl(Graphic User Interface) has been built on the base of MFC(Microsoft Foundation Class). The program is organized as modules by classes based on VTK-library, and these classes are made to function through inheritance and cooperation which are an important and valuable concept of object-oriented programming. The major functions of this post-processor program are introduced and demonstrated, which include contour plot, surface plots, cut plot and clip plot as well as view manipulation (translation, rotation, scaling etc).

• 융복합기술연구소 논문집
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• 제2권1호
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• pp.43-48
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• 2012

Generally, in-plane position of moving object is measured referring to the reference pattern attached to the object. From optical camera to magnetic reluctance probe, there are many ways detecting a variation of the periodical pattern. In this paper, the various operating principles developed for in-plane positioning are reviewed and compared each other. And, a novel method measuring large rotation as well as x, y linear displacements is suggested, including a detailed description of the overall system layout. It is a modified version of the surface encoder, which is a robust digital measuring method. From the surface encoder, the rotation of an object is measured indirectly through a compensated input of optical servo and independently of linear displacements. So, the operating range can be extended simply by enlarging the reference pattern, without magnifying the decoding units.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.649-652
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• 1992

ECR(Electron Cyclotron Resonance) occure at ${\omega}_c$=${\omega}$, ${\omega}_c$:electron cycltron frequency, ${\omega}$:electromagnetic wave frequency. ECR system have several merit, 1) power transefer efficiency 2) low neutral gas pressure (below 1 mTorr) 3) high plasma density($10^{12}$ $cm^{-3}$). It is applicated variously in the field of semiconductor and new materials as the manufacturing equipment. Magnetic field in ECR system contruct resonance layer (${\omega}$=2.45GHz, $B_z$=875 Gauss) and control plasma. Plasma is almost generated at resonance layer. If the distance between substrate and resonance layer is short, uniformity of plasma is related with profile of resonance layer. Plasma have the property "Cold in Field", so directonality of magnetic field is one of the control factors of anisotropic etching. In this study, we calculate B field and flux line distribution, optimize geometry and submagnet current and improve of magnetic field directionality (99.9%) near substrate. For the purpose of calculation, vector potential A(r,z) and magnetic field B(r,z), green function and numerical integration is used. Object function for submagnet optimization is magnetic field directionality on the substrate and Powell method is used as optimization skim.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.107-109
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• 2007

Pancake windings have merits that are easier to make high field magnets and replace windings when an accident happens and windings are aged. The current of the whole magnet consisted of windings connected in series was limited by the minimum current of the top and bottom pancake windings where maximum perpendicular magnetic field was applied. This paper propose a optimal design of a HTS magnet excited by a single source, where evolution strategy was adopted for optimal design algorithm. A magnet consisted of 8 BSCCO pancakes was chosen to prove the effectiveness of this optimal design method. Magnetic field at the center of a magnet was chosen as the object function and it was used maximized. Results of the optimal design shows that the increment of the number of turns of the pancake winding make the magnetic field of the center of the magnet increase but the current of the winding decrease for the larger perpendicular magnetic field.