• Journal of the Korean Magnetics Society
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• v.8 no.5
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• pp.300-307
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• 1998

The $Co_{90}Fe_{10}$ single layer films were deposited on various substrates (glass, Si, polymide) using high vacuum RF magnetron sputtering system and nominall 1000 $\AA$ thick $Co_{90}Fe_{10}$ alloy films had a good high frequency characteristic. $M_S$ and $H_{an}$ values obtained from the B-H characteristic of the $10{\times}[100 nm \;Co_{90}Fe_{10}/100 nm\; SiO_2]$ multilayers agreed well with those obtained by calculation. Complex relative permeability $(={\{\mu}_r={\mu}_r',-j{\mu}$\mu$_r")$ at frequency f was measured from the transmission characteristics $(S_{11},\; S_{21}\;parameters)$ of the microstrip line which has a stacked structure consisting of sample magnetic films and a conductor and is connected to a network analyzer. The ${\mu}_r'-f$ characteristic was abtained from the megnetic absorption, which was analyzed from the S-parameter characteristics of the microstrip line. The ${\mu}_r'-f$ characteristic was also calculated from the ${\mu}_r"-f$-f characteristic using the Kramers-Kronig relation. The measurement results were confirmed to agree well with those obtained by calculations.culations.

• Journal of the Korean Electrochemical Society
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• v.16 no.3
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• pp.111-122
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• 2013

Sodium sulfur (NAS) battery is a high energy storage system (ESS). These days, as the use of renewable green energy like wind energy, solar energy and ocean energy is rapidly increasing, the demand of ESS is increasing and NAS battery is considered to be one of the most promising ESS. Since NAS battery has a high energy density(3 times of lead acid battery), long cycle life and no self-charge and discharge, it is a good candidate for ESS. A NAS battery consists of sulfur as the positive electrode, sodium as the negative electrode and ${\beta}$"-alumina as the electrolyte and a separator simultaneously. Since sulfur is an insulator, carbon felt should be used as conductor with sulfur and so the composition and property of the cathode could largely influence the cell performance and life cycle. Therefore, in this paper, the composition of NAS battery, the property of carbon felt and sodium polysulfides ($Na_2S_x$, intermediates of discharge), and the effects of these factors on cycle performance of cells are described in detail.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.8
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• pp.819-826
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• 2002

In this paper, the performance of Au / $Ba_{0.5}Sr_{0.5}TiO_3$ (BST) / Magnesium oxide (MgO) two-layered electrically tunable band-pass Filters (BPFs) is demonstrated. The devices consist of microstrip, coplanar waveguide (CPW), and conductor-backed coplanar waveguide (CBCPW) structures. These BST thin film band-pass filters have been designed by the 2.5 D field simulator, IE3D, Zeland Inc., and fabricated by thin film process. The simulation results, using the 2-pole microstrip, CPW, and CBCPW band-pass filters, show the center frequencies of 5.89 GHz, 5.88 GHz, and 5.69 GHz, and the corresponding insertion losses are 2.67 dB, 1.14 dB, and 1.60 dB, with 3 %, 9 %, and 7 % bandwidth, respectively. The measurement results show the center frequencies of 6.4 GHz, 6.14 GHz, and 6.04 GHz, and their corresponding insertion losses are 6 dB, 4.41 dB, and 5.41 dB, respectively, without any bias voltage. With the bias voltage of 40 V, the center frequencies for the band-pass filters are measured to be 6.61 GHz, 6.31 GHz, and 6.21 GHz, and their insertion losses are observed to be 7.33 dB, 5.83 dB, and 6.83 dB, respectively. From the experiment, the tuning range for the band-pass filters are determined as about 3 % ~ 8 %.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.11 s.114
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• pp.1120-1131
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• 2006

This paper describes the numerical analysis techniques using the Combined Integration/Matrix Method to calculate ground potential rise which can be occurred in the various grounding systems. Combined Integration/Matrix Method is used to reduce the error and computation time with the analytical integration equation and the proper segmentaion of earth embedded conductor. To do it, optimal segmentaion method for the buried conductors is presented through error analysis which is capable of applying the practical scaled various grounding systems. The optimum length of segmented element is much co-related with the buried depth of grounding electrode and the maximum length of buried electrode. As a result, less 3 precent errors was obtained by proposed model. The proposed model is applied to verify an effect of multi-grounding problems which was aroused much controversy with separated or common grounding between the high power grounding system and low power grounding system such as signal and telecommunication grounding.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.5
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• pp.613-623
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• 2012

In this paper, we present an ultra miniaturized voltage tuned oscillator, with HMIC-type amplifier and phase shifter, using LTCC artificial dielectric resonator. ADR which consists of periodic conductor patterns and stacked layers has a smaller size than a dielectric resonator. The design specification of ADR is obtained from the design goal of oscillator. The structure of the ADR with a stacked circular disk type is chosen. The resonance characteristic, physical dimension and stack number are analyzed. For miniaturization of ADRO, the ADR is internally implemented at the upper part of the LTCC substrate and the other circuits, which are amplifier and phase shifter are integrated at the bottom side respectively. The fabricated ADRO has ultra small size of $13{\times}13{\times}3mm^3$ and is a SMT type. The designed ADRO satisfies the open-loop oscillation condition at the design frequency. As a results, the oscillation frequency range is 2.025~2.108 GHz at a tuning voltage of 0~5 V. The phase noise is $-109{\pm}4$ dBc/Hz at 100 kHz offset frequency and the power is $6.8{\pm}0.2$ dBm. The power frequency tuning normalized figure of merit is -30.88 dB.

• Journal of the Korean Institute of Gas
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• v.8 no.4 s.25
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• pp.62-69
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• 2004

It is necessary to eliminate the electric static for the prevention of disasters by electric static discharge, the improvement of production efficiency, the protection of a sensitive electronic devices in the variable manufacturing processes. Then it is handled for elimination of electric static in the painting plant, the film manufacturing plant, the producing semi-conductor factory. This study described on the ideal condition of electric static elimination efficiency by changing of the length of voltage input type eliminator's bar, the length of copper pipe and the gap of electrode and the existence of explosion by inflammable gas with that conditions. As the result, the electric static elimination efficiency has the most ideal value at the 8-11(mm) gap of the earth electrode and needle type electrode each elimination bar and there is not explode at the explosive experiment of inflammable gas with the ideal elimination bar. We can consider that there are some data which are needed for elimination efficiency and it will be able to protect the occurrence of explosion accident inflammable nas in the industrial fields.

• Journal of the Korean Institute of Gas
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• v.20 no.6
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• pp.1-8
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• 2016

Gu-mi hydrogen fluoride leak accident in 2012 was amplified social anxiety for chemical accidents. To relieve these anxieties Off-site Risk Assessment was introduced in 2015. Off-site Risk Assessment is targeted at most chemicals, and most of the high-pressure-toxic gases which are mainly used in high-tech industries such as semi conductor, display, Photovoltaic panels industry are included in the substance of the Off-site Risk Assessment. Since Korean companies occupy a high market share in high-tech industries, high pressure-toxic domestic gas consumption is constantly increasing. Accordingly, it is expected to increase the possibility of accidents. In accordance with the circumstances, this study was to conducted Consequence Analysis(CA) about high pressure-toxic gases those are high demand in domestic. CA was used for ALOHA developed by US EPA & US NOAA and the CA result of Arsine was the largest at 4,700 m. CA results are expected to be utilized for determining the effective Safety distances when high pressure-toxic gas leak.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.7
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• pp.1393-1398
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• 2009

Conventionally, etching is first considered for microelectronics fabrication process and is specially important in process of a-Si:H thin film transistor for LCD. In this paper, we stabilize properties of device by development of wet and dry etching process. The a-Si:H TFTs of this paper is inverted staggered type. The gate electrode is lower part. The gate electrode is formed by patterning with length of 8 ${\mu}$m${\sim}$16 ${\mu}$m and width of 80${\sim}$200 ${\mu}$m after depositing with gate electrode (Cr) 1500 ${\AA}$under coming 7059 glass substrate. We have fabricated a-SiN:H, conductor, etch-stopper and photo resistor on gate electrode in sequence, respectively. The thickness of these thin films is formed with a-SiN:H (2000 ${\mu}$m), a-Si:H(2000 ${\mu}$m) and n+a-Si:H (500 ${\mu}$m), We have deposited n-a-Si:H, NPR(Negative Photo Resister) layer after forming pattern of Cr gate electrode by etch-stopper pattern. The NPR layer by inverting pattern of upper gate electrode is patterned and the n+a-Si:H layer is etched by the NPR pattern. The NPR layer is removed. After Cr layer is deposited and patterned, the source-drain electrode is formed. In the fabricated TFT, the most frequent problems are over and under etching in etching process. We were able to improve properties of device by strict criterion on wet, dry etching and cleaning process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.160-166
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• 2018

The worldwide semi-conductor market has been growing for a long time. Manufacturing lines of semi-conductors need to handle several types of toxic gases. In particular, they need to be controlled accurately in real time. This type of toxic gas control system consists of many different kinds of parts, e.g., fittings, valves, tubes, filters, and regulators. These parts obviously need to be manufactured precisely and be corrosion resistant because they have to control high pressure gases for long periods without any leakage. For this, surface machining and hardening technologies of the metal block and metal gasket need to be studied. This type of study depends on various factors, such as geometric shapes, part materials, surface hardening method, and gas pressures. This paper presents strong concerns on a series of simulation processes regarding the differences between the inlet and outlet pressures considering several different fluid velocity, tube diameters, and V-angles. Indeed, this study will very helpful to determine the important design factors as well as precisely manufacture these parts. The EP (Electrolytic Polishing) process was used to obtain cleaner surfaces, and hardness tests were carried out after the EP process.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12B
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• pp.1452-1458
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• 2009

In this paper, Our proposed Multipurpose Complex Card UHF band RFID small-size Tag antenna. Multi purpose Complex Card UHF band RFID small-size Tag antenna that is to minimize the low efficiency of RFID Tag Read Range that generates space limitation and a conductor surrounded by inducing fingerpring system with dual(HF, UHF) Card is presented. Our proposed UHF band RFID small-size Tag antenna is for the Multipurpose Complex Card that is mounted on the fingerpring system as well as the HF Tag. It also enables to minimize and facilitates Tag chip matching by adjusting Tapered, Meander line and Loop structure. Given the card substance properties and periphery circuit, the proposed small-size Tag antenna, in this report, is designed with PET film with size of $50{\times}15mm^2$. The RFID small-size Tag method for measurements is used by EPCglobal Static Test instrument in Anechoic Chamber, which is tested with dual Card, within the car and in wallet. It is found that Read Range is 3.8m from the EPCglobal Static Test, Maximum Read Range within the car from the field test results in 7.6m. Proposed Tag antenna is will be used in the parking control security system.