• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1992년도 춘계학술대회 논문집
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• pp.129-132
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• 1992

Rutile was among the first dielectric materials used. However, rutile exhibits a very high temperature coefficient of capacitance (about -750[ppm/$^{\circ}C$]) which resticts its practical application. Since this first use of titania, other materials have also been studied with the object of decreasing the temperature dependence whilst retaining favorable dielectric loss, Q, and relative permittivity. The temperature coefficient of temperature compensation capacitor is +100~750[ppm/$^{\circ}C$], dielectric constant 10~150. Low loss ceramics with dielectric constants in the 10～150 range also found application. Recently, their applications are extended in EMI filter and dielectric materials for microwave. There temperature coefficient of dielectric materials approaches 0[ppm/$^{\circ}C$]. The dielectric preperties of zirconia titanate ceramics prepared by addition of $Ta_2O_{5}$ were investigated.

• Journal of Ceramic Processing Research
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• 제13권spc2호
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• pp.241-245
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• 2012

The barrier rib on plasma display panel (PDP) is a typical 3D-patterned thick film with thickness of 120 ㎛ and it is hard to measure its dielectric constant in this state of the product. Because the porosity of ceramic thick film influenced the mechanical and dielectric characteristics, it was expected that there was the relationship between two properties. Therefore, the correlation analysis between porosity, hardness and dielectric constant of the barrier rib was studied and the exponential curve between porosity and hardness, and the quadratic curve between porosity and dielectric constant were drawn. The dielectric constant was well related to hardness by K400kHz = 0.5672 + 5.695 ln(Hv). The hardness was measured at five points on two real panels which sintered by two types of profiles and then dielectric constants and deviation were estimated by the above equation.

• 동력기계공학회지
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• 제17권6호
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• pp.63-72
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• 2013

The main purpose of this study is to analyze the collection characteristics of multi-layer multi-stage porous plate system with ionizer and dielectric-substance experimentally. The experiment is carried out to analyze the characteristics of pressure drop and collection efficiency for the present system with experimental parameters such as applied voltage, inlet velocity, stage number and inlet particle concentration, etc. In results, for multi-layer multi-stage porous plate system of inflow type, at 5 stage and $v_{in}$=2.58 m/s, the pressure drop becomes lower 15 $mmH_2O$ as 95 $mmH_2O$ than that of non-inflow type system. It is estimated that for the present system with ionizer and dielectric-substance, the collection efficiency represents 98.5% showing higher 5.2% comparing to that of multi-layer multi-stage porous plate system without ionizer and dielectric-substance at 5 stage, $v_{in}$=2.58 m/s and inlet concentration $3g/m^3$(fly ash).

• 대한전자공학회논문지
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• 제26권7호
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• pp.8-12
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• 1989

페라이트 층을 갖는 유전체 도파관이 갖는 비가역 전자파 전파특성을 아이솔레이터와 같은 비가역 소자에 응용 가능하도록 페라이트로 되어 있는 격자 구조를 제시하였다. 격자 구조를 유전체 도파관의 계단형 불연속이 cascade로 연결된 것으로 보고, 모드 정합법으로 구한 계단형 불연속의 산란 행렬을 이용하여 격자 구조의 특성을 해석하였다. 주기적인 격자 구조의 저지 주파수 대역이 사용하고자 하는 주파수 근처에 있을 때와 상당히 떨어져 있는 두 경우의 비가역 산란 특성을 35GHz 근처에서 해석하였으며, X-Band에서 제안된 격자 구조를 제작 실험하였다.

• 마이크로전자및패키징학회지
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• 제20권2호
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• pp.33-38
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• 2013

In this study, both a finite element analysis and an experimental analysis are executed to investigate the mechanical characteristics of dielectric material effects on warpage. Also, viscoelastic material properties are measured by DMA and are considered in warpage simulation. A finite element analysis is done by using both thermal elastic analysis and a thermo-viscoelastic analysis to predict the nonlinear effects. For experimental study, specimens warpage of non-symmetric structure with body size of $22.5{\times}22.5$ mm, $37.5{\times}37.5$ mm and $42.5{\times}42.5$ mm are measured under the reflow temperature condition. From the analysis results, experimental warpage is not similar to FEA results using thermal elastic analysis but similar to FEA results using thermo-viscoelastic analysis. Also, its effect on substrate warpage is increased as core thickness is decreased and body size is getting larger. These FEA and the experimental results show that the nonlinear characteristics of dielectric material play an important role on substrate warpage. Therefore, it is strongly recommended that non-linear behavior characteristics of a dielectric material should be considered to control warpage of FCBGA substrate under conditions of geometry, structure and manufacturing process and so on.

• 조명전기설비학회논문지
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• 제29권8호
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• pp.32-39
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• 2015

This paper presents the surface flashover mechanism of a laminated solid dielectric and describes the surface flashover characteristics with the inherent capacitance of the laminated solid dielectric in a $N_2/O_2$ mixture gas (8:2) under an quasi uniform field. It was found that the electron emission at a cathode and the high-local electric field region around an anode were important factors to reasonably describe the surface flashover mechanism. The surface flashover voltage by the mechanism decreased with the inherent capacitance increase of the laminated solid dielectric. In addition to the surface flashover mechanism and its characteristics, the surface flashover voltage equations as a function of the inherent capacitance were derived by considering a gas pressure used in future eco-friendly GIS and the factors influencing the surface flashover.

• 조명전기설비학회논문지
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• 제17권3호
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• pp.56-63
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• 2003

수표면을 전극으로 사용한 부성방전형 오존발생기를 제안하고 수표면의 바로 아래에 유전체구를 설치함으로써 오존발생특성을 향상시킬 수 있었다. 이때, 서로 다른 유전율을 갖는 유전체구를 사용하여 수표면에 형성되는 방전조건을 변화시키고자 하였다. 전류-전압특성과 오존발생특성을 조사하였고 방전현상을 관찰하기 위해 유리구슬 유전체를 사용한 경우의 방전모양을 사진 촬영하여 분석하였다. 수표면에 발생되는 수돌기의 크기는 교락현상(breakdown)의 원인이 될 수 있고 따라서 오존발생량을 감소시킨다. 본 연구에서는 수표면 바로 아래에 서로 다른 유전율을 갖는 유전체구를 투입함으로써 과도한 크기의 수돌기(Tayler cone)의 놀이를 제한할 수 있었다. 이에 따라, 유전체구를 사용하지 않은 경우보다 많은 양의 오존을 발생시킬 수 있었다. 수중에 투입되는 유전체의 유전율이 증가함에 따라 방전이 시작되는 전압을 앞당길 수 있었고 강유전체구를 사용한 경우 최대 110[ppmv]의 오존발생량을 얻을 수 있었다.

• 전기학회논문지
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• 제59권12호
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• pp.2250-2255
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• 2010

An fine silver particle has a variety of uses, such as in killing micrograms and as catalysts. Many techniques have been used for the production of the fine particles. Faraday cell, consisting of two silver electrodes in an electrolyte, is unique, but it is hard to get a very fine particle by this method. A finer silver nano-particle producing cell, utilizing a dielectric bed as a lower electric current and higher field controlling means, has been proposed and investigated. The I-V characteristics of the cell and effect of the dielectric bed on the producing finer silver nano-particles have been investigated. The I-V characteristics of the cell with the dielectric bed were different from that of the same system without the bed, due to the increased cell resistance and elevated electric field intensity. It is found that the proposed cell with the dielectric bed can produce finer silver nano-particles effectively, which, however, can be used as one of effective fine silver nano-particle producing means.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.292-293
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• 2006

We have Investigated dielectric properties depending on bias voltage in organic lightemitting diodes using 8-hydroxyquinoline aluminum($Alq_3$) as an electron transport and emissive material. We analyzed the dielectric properties of organic light emitting diodes using impedance characteristics measurement by the auto-balancing bridge technique and equivalent cirrcuit of ITO/$Alq_3$/Al. Impedance characteristics was measured complex impedance Z and phase ${\theta}$ in the frequency range of 40 [Hz] to $10^8$ [Hz]. We obtained complex electrical conductivity, dielectric constant, and loss tangent ($tan{\delta}$) of the device at room temperature. From these analyses, we are able to interpret a conduction mechanism and dielectric properties contributed by an interfacial and orientational polarization.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.738-743
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• 2004

The microwave dielectric properties and their related structural characteristics in solid solutions of (1-x) $Ba(Mg_{1/3}Nb_{2/3})O_3$ -x $La(Mg_{2/3}Nb_{1/3})O_3$ (BLMN) have been investigated by measuring the dielectric constant${\varepsilon}r)$, Q value and temperature coefficient of resonant frequency$({\tau}f)$ and by observing the crystal structure using high resolution transmission electron microscopy (HRTEM). Microwave dielectric properties showed characteristic features for specific composition. Dielectric constant$({\varepsilon}r)$ showed maximum value at the composition which corresponds to the phase boundary between 1:2 ordered and 1:1 ordered structure. The increase in ${\varepsilon}_r$ may be caused by the rattling of ions by incorporating smaller ions and the disordered structure. The variation of temperature coefficient of resonant frequency${{\tau}_f)$ was investigated in terms of oxygen octahedra tilting.