• 한국전기전자재료학회논문지
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• 제19권8호
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• pp.780-784
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• 2006

We present high aspect ratio air-core solenoid inductors with $100{\mu}m\;and\;200{\mu}m$ tall via structures on Pyrex wafer. The effect of various parameters such as different number of turns, via heights, pitch distance between turns on inductor's radio frequency (RF) characteristics have been studied. The highest Q factor we obtained from various solenoid inductors is 72.8 at 9.7 GHz, which was produced by a 3-turn inductor.

• 대한전기학회논문지
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• 제39권3호
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• pp.247-253
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• 1990

The inductances of air-core solenoid magnets with circular cross sections depend on the geometric structure and winding number. For the calculation of the inductance of these magnets, Grover's table is normally used. This study presents a method to calculate the inductance using finite element method. The result of the computation agrees well with those found in the literature. Inductances of solenoid magnets with nonuniform winding distribution of complicated shapes can also be computed using this method.

• 한국초전도ㆍ저온공학회논문지
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• 제18권1호
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• pp.50-54
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• 2016

In this paper, a hybrid method is proposed to design an air-core superconducting solenoid system for 6 T axial uniform magnetic field using Niobium Titanium (NbTi) superconducting wire. In order to minimize the volume of conductor, the hybrid optimization method including a linear programming and a nonlinear programming was adopted. The feasible space of solenoid is divided by several grids and the magnetic field at target point is approximated by the sum of magnetic field generated by an ideal current loop at the center of each grid. Using the linear programming, a global optimal current distribution in the feasible space can be indicated by non-zero current grids. Furthermore the clusters of the non-zero current grids also give the information of probable solenoids in the feasible space, such as the number, the shape, and so on. Applying these probable solenoids as the initial model, the final practical configuration of solenoids with integer layers can be obtained by the nonlinear programming. The design result illustrates the efficiency and the flexibility of the hybrid method. And this method can also be used for the magnet design which is required the high homogeneity within several ppm (parts per million).

• 유공압시스템학회논문집
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• 제7권4호
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• pp.44-49
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• 2010

This paper represents solenoid design of control valve for incline angle control in variable compressor. Some theoretical and numerical analysis were performed to analyse solenoid and compared with experimental results. Maxwell program was used for numerical analysis. Through redesigns of housing body, plunger, core, and disk in control valve, the needed force was gotten. Reduction of core groove and housing body air-gap had a large influence on magnetic force. But increasing of disk thickness had little effect on magnetic force. Control valve efficiency could be improved through solenoid redesign.

• 한국초전도ㆍ저온공학회논문지
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• 제17권2호
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• pp.31-35
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• 2015

Mapping is a useful tool in the magnetic field analysis and design. In some specific research area, such as the nuclear magnetic resonance (NMR) or the magnetic resonance imaging (MRI), it is important to map the magnetic field in the interesting space with high accuracy. In this paper, an indirect mapping method in the center volume of an air-core solenoid is presented, based on the solution of the Laplace's equation for the field. Through the mathematical analysis on the mapping calculation, we know that the condition number of the matrix, generated by the measurement points, can greatly affect the error of mapping result. Two different arrangement methods of the measurement points in field mapping are described in this paper: helical cylindrical line (HCL) method and parallel cylindrical line (PCL) method. According to the condition number, the HCL method is recommended to measure the field components using one probe. As a simple example, we mapped the magnetic fields in a MRI main magnet system. Comparing the results in the different methods, it is feasible and convenient to apply the condition number to reduce the error in the field mapping calculation. Finally, some guidelines were presented for the magnetic field mapping in the center volume of the air-core solenoid.

• Journal of Mechanical Science and Technology
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• 제16권12호
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• pp.1643-1651
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• 2002

Magnetic levitation systems are required to have a large operating range in many applications. As one method to solve this problem, Time Delay Control (TDC) is applied to a single-axis magnetic levitation system in this paper A reduced-order observer is utilized to estimate states excluding measurable states in the control law. The system consists of a square air-core solenoid and a circular permanent magnet attached on a plastic ball. Theoretical magnetic forces of the system are obtained on the basis of the location of the magnet around the solenoid. The magnetic levitation force is obtained by the experiment, and then compared with the theoretical one. As the results of the control experiments, the nonlinear controller (TDC : 1-2 ㎜) has a larger operating range than the linear controller (PD control : 1-1.4 ㎜), and is superior to linear. control in the robustness to the modeling uncertainty and the performance of the disturbance rejection.

• 한국자동차공학회논문집
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• 제12권1호
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• pp.190-195
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• 2004

An exhaust brake system is composed of a gate valve, a pneumatic cylinder and an on-off solenoid valve. An on-off solenoid valve which is a key component of the exhaust brake system ought to have characteristics such as high reliability and long life for reducing the foot brake and tires damage, and for driver's fatigue relief of middle/large size vehicles running a long distance. In this paper, an on-off solenoid valve which is used for vehicle brake system was studied. For the performance evaluation of the on-off solenoid, electromagnetic characteristics and dynamic characteristics are analyzed. On the basic study for the performance improvement of exhaust brake system, pneumatic circuit and pneumatic valve of on-off solenoid type were suggested and the performance of pneumatic valve through the test procedure was evaluated.

• 한국정밀공학회지
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• 제11권6호
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• pp.127-135
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• 1994

This paper is concerned about a high speed electromagnet of Pressure control solenoid valve. Solenoid valve is controlled by means of Pulse width modulation. The magnetostatic field problem on a solenoid is numerically solved by the 2-D axisymmetric finite element method. And permeance method is adopted for analysing the static and dynamic property of solenoid part theoretically. In addition, in this study, experiments on solenoid part were performed in order to measure the magnetic force and plunger displacement. The numerical results coincided with the experimental results. As a result, the magnetic force has the linear relation with displacement of plunger and the primary factors on the performance of PWM type high speed electromagnet are coil resistance, plunger mass, and the length of air gap between plunger and core.

• 대한기계학회논문집A
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• 제24권5호
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• pp.1166-1174
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• 2000

In this paper, we introduce a positioner based on magnetic levitation to eliminate the friction which is the most severe effect to limit high resolution on the micro level. Differently from existing electromagnetic device, the proposed positioner consists of air core solenoid and permanent magnet. Although the combination produces small magnetic force, it is suitable for realizing micro motion repeatedly without the accumulation of error because there is no hysteresis caused by ferromagnetic materials, no eddy current loss, no flux saturation. First, the approximate modeling of stiffness and damping effects between the magnetic elements is made and verified experimentally. Then, we have formulated the dynamic equation of one d.o.f magnetic levitation positioner using linear perturbation method and discussed the necessity of optimization for the chief design parameters to maximize the stability performance.

• 한국초전도ㆍ저온공학회논문지
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• 제16권4호
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• pp.53-56
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• 2014

A numerical method of magnetic field calculation for the air-core solenoid is presented in this paper. In application of the Biot-Savart law, the magnetic field induced from the source current can be obtained by a double integration ormula. The numerical method named composite Simpson's rule for the integration is applied to the program and the adaptive quadrature method is used to adjust the step size in the calculation according to the precision we need. When the target point is in the solenoid and the intergrand's denominator may be zeroin the process of calculation, the method sill can provide an appropriate result. We have developed a program which calculates the magnetic field with at least 1ppm precision and named it as rzBI() to implement this method. The method has been used in the design of an MRI magnet, and the result show it is very flexible and convenient.