• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.785-788
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• 2005

In this study, micro-scale, high-performance, solenoid-type RF chip inductors were investigated. The size of the RF chip inductors fabricated in this work was $1.0{\times}0.5{\times}0.5mm^3$ The material and shape of the core were 96% $Al_2O_3$ and I-type. The material and number of turn of coil were copper (Cu) and 6. The diameter ($40{\mu}m$) of coil and length (0.35mm) of solenoid were determined by a Maxwell three-dimensional field simulator to maximize the performance of the inductors. High frequency characteristics of the inductance (L) and quality-factor (Q) of developed inductors were measured using an RF Impedance/Material Analyzer (HP4291B with HP16193A test fixture). The inductors developed have inductances of 10.8nH and quality factors of 25.2 at 250MHz, and show results comparable to those measured for the inductors prepared by CoilCraftTm that is one of the best chip inductor company in the world. The simulated data predicted the high-frequency data of the Land Q of the inductors developed well.

• 연구논문집
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• s.30
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• pp.147-157
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• 2000

The filtered vacuum arc source (FVAS), which is adopted by magnetic filtering methode to remove the macro-particle in vacuum arc plasma, was composed of a torus structure with bending angle of 60 degree. The radius of torus was 266 mm, the radius of plasma duct was 80 mm and the total length was 600 mm. The magnet parts were consisted of one permanent magnet, one magnetic yoke and five solenoid magnets. The plasma duct was electrically isolated from the ground so that a bias voltage could be applied. The baffles inside plasma duct were installed in order to prevent the recoil effect of macro-particles. Graphite was used as the cathode material to coat the amorphic diamond film and its diameter was 80 mm. The amorphic diamond film attracts much attention due to its excellent mechanical, optical and tribological properties suitable for wide range of applications. The effects of solenoid magnet in plasma extraction were studied by computer simulation and experiment using Taguchi's method. The source and extraction magnet affected the arc stabilization. The extraction beam current was maximized with low value of the source magnet current and high value of the filtering magnet current. Optimum deposition condition was obtained when the currents of arc discharge, source, extraction, bending, deflection and outlet magnet were 30 A, 1 A, 3 A, 5 A, and 5 A, respectively.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.8
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• pp.2480-2490
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• 1996

This paper presents a new type of hydraulic servo chllinder which is characterized by its simple construction and an ubtegrated feedback mechanism. Piston position of the cylinder is controlled by eletrical input and mechamical feedback deduced from its own structure. Hydraulic pressure in each cylinder room is controlled by a poppet valve. The poppet is activated by a solenoid and is linked to the piston. Solenoid input current pulls up the poppet, which results in pressure drop and thus piston motion. The piston motion generates pull down force on the poppet by the linkage and the motion stops at equilibrium. In that way the piston position is controlled by an expernal input current. Characteristics of the servo cylinder is verified by stability analysis, tranient vehavior and steady state positing for step input. Design parameter analyses have been executed by derivation of analytical approximate solutions and by computer simulations. A prototype hydraulic servo cylinder is developed and tested. The experimental results show successful function of the servo cylinder and consistency with the theoritical results.

• Bulletin of the Korean Space Science Society
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• 1995.04a
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• pp.21-21
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• 1995

The structures of 17GHz microwave burst for bipolar sunspots have investigated. which included the effects of the projected shapes of radio sources as they traverse across the solar disk using a magnetic loop employing a model of solenoid coils. An ensemble of high-energy electrons confined in the loop be assumed. The projected brightnesls distributions of gyrosynchrotron emission in x- and o-modes are computed and converted into total intensity and circular polarization difference at 17GHz for various heliocentric distances using numerical integration of the transfer equation along the line of sight. The results of computations at 17GHz for optical thin case will be presented. and the effects of the orientation of the loop will be discussed in detail, as well as the effect of size, position, Structure, and polarization of the emission. Also the results of the various physical P8lrameters such as the strength of magnetic field. high and low energy cut-off of accelerated electrons. spectral index and density of electrons will be preslmted. After comparing the results of model calculation with observations. we found that the observations can be well explained in terms of a loop model and its projection effect.effect.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2000.11a
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• pp.143-151
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• 2000

Dissolved silica is make some critical trouble at steam turbine. And, we must measure it to ppb level. We were looking for the best measuring method of the silica. Via this study, we could found it in the N-IR spectroscopy technology. This dissertation have been discuss about system structure, system fundamentals and performance test. At the test, we were study in the spectral interference of $NH_3$. We know that existing system had some problem. It is structural frailties of single beam type. Therefore we were study for double beam type structure. And we obtain a good result. In the result, it have been discuss that conduct a test of $NH_3$ effect.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.2
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• pp.192-201
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• 2001

Analyzing internal structure, flow rate and dynamic behavior characteristics of electronically controlled shock absorber, damping performance limit is identified to comprise the two reciprocal characteristics of ride comfort and handling safety. Regardless of its lower performance than the active suspension control system, the semi-active suspension control system has been taking interest because of its absolutely higher performance than passive suspension system. Since the pervious studies have been concentrated mostly on analytic aspect and survey on the internal structure of the shock absorber remain insufficient, the main discourse of this paper is focused on analyzing the nonlinear shock absorber which varies the damping force of semi-active suspension system and the dynamic characteristics of the solenoid valve, a sort of pressure valve, and proposing the design factors of importance.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.53-54
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• 2006

Experimental analyses on the Hydroelastic Flow-Structure Interactions on pulsed impinged jet is measured with the FSIMS(Flow-Structure Interaction Measurement System. The nozzle diameter is D=15mm and two major experiments have been carried out for the cases of the distance between the nozzle tip to the elastic wall is 6.0. The pulsed jets were controlled by a solenoid valve and were impinged onto an elastic plate (material: silicon, diameter: 350mm, thickness: 0.5mm, hardness: 15). The Reynolds numbers were 20,000 and 24,000 when the jets were impinged with the volume velocities. The results showed that the elastic plate moved slightly to the opposite direction of the jet direction at the time of valve opening. It has been shown that the vortices travelling over the surface of the wall made the elastic wall distorted locally due to a vector forces between rotating forces of the vortex and a newly-incoming flow.

• Journal of the Korean Vacuum Society
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• v.10 no.4
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• pp.431-439
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• 2001

In this paper, the a-Diamond films were synthesized using filtered vacuum arc source (FVAS), FVAS was composed of a torus structure with bending angle of 60 degree. The radius of torus was 266 mm, the radius of plasma duct was 80 mm and the total length was 600 mm. The magnet parts were composed of one permanent magnet and five solenoid magnets. The plasma duct was electrically isolated from the ground so that a bias voltage could be applied. The baffles inside plasma duct were installed in order to prevent the recoil effect of macro-particles. Cathode was made of graphite with 80 mm in diameter. The effects of solenoid magnet on plasma extraction were investigated by computer simulation and experiment using Taguchi's methode. The source and extraction magnet affected the arc stabilization. The extraction beam current was maximized with low value of the source magnet current and high value of the filtering magnet current. The beam current density was 3.2 mA/$\textrm{cm}^2$ and average deposition rate was 5 $\AA$/sec when the currents of arc discharge, source, extraction, bending, deflection and outlet magnet were 30 A, 1 A, 3 A, 5 A, 5 A, and 5 A, respectively. The beam current density and the efficiency of beam transportation were increased with the positive bias voltage of the plasma duct.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.5
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• pp.179-187
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• 2001

In this paper, a primary pressure regulating type ratio control system is developed for a metal belt CVT, and the CVT ratio changing characteristics are investigated by simulation and experiment. The hydraulic part of the ratio control system has a simple structure with one 3-way spool valve as a main ratio control valve and one bleed type variable force solenoid as a pilot valve. The mathematical modelling of the CVT hydraulic system is derived by considering the CVT shift dynamics. Simulation results of CVT speed ratio and the primary pressure agree with the experimental results demonstrating the validity of the dynamic models. It is found from the simulation and experimental results that the response time of speed ratio and primary pressure can be shortened by increasing the ratio control valve port area, and the size of feedback orifice of ratio control valve gives a damping effect on the primary pressure oscillation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.577-580
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• 1995

This paper suggests direct-acting hydraulic circuit to control clutches and brakes in automatic transmission. As only one pressure control valve controls the pressure of several friction elements with accumulators in conventional hydraulic circuit, the controllable range is limited. In addition, it is difficult to control the fine timing between apply clutch and release clutch. So, we designed new method to control the pressure of clutch which uses ressure control valve and pressure control solenoid valve independently in each friction element. through this structure improvement of hydraulic circuit, we can control the pressure of clutches and brakes finely and fine timing of between apply clutch and release clutch.