• 한국전기전자재료학회논문지
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• 제22권1호
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• pp.53-60
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• 2009

$ZrTiO_4$ dielectric thin films were coated by metal-organic decomposition, and annealed by rapid thermal processing up to $900^{\circ}C$ for their crytallization. Crystallized single-phase $ZrTiO_4$ thin films were fabricated above the annealing temperature of $800^{\circ}C$, but their grains were randomly oriented without specific textured orientation. Best dielectric properties were presented by the sample annealed at $800^{\circ}C$ which had crystalline structure and flat surface. Dielectric constant of the film was maintained at 32 throughout full frequency range up to 6 GHz, and dielectric loss was varied between 0.01 and 0.04.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 춘계학술대회 논문집
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• pp.325-329
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• 1998

In this paper, the (Sr$_{1-x}$ Ca$_{x}$)TiO$_3$(SCT) thin films were deposited at various substrate temperature using RF magnetron sputtering method on optimized Pt-coated electrodes (Pt/TiN/SiO$_2$/Si). An influence of substrate temperature and annealing temperature on the structural and dielectric properties are investigated. The substrate temperature changed from 100[$^{\circ}C$] to 500[$^{\circ}C$] and crystalline SCT thin films were deposited abode 400[$^{\circ}C$]. All thin films had (111) preferred orientation, the (100) oriented films were obtained at the substrate temperature above 400[$^{\circ}C$]. The dielectric constant changes almost linearly in the temperature region of -80~+90[$^{\circ}C$], the temperature characteristics of the dielectric loss exhibited a stable value within 0.1, then not affected by substitutional contents. The capacitance characteristics appears a stable value within $\pm$5[%].

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1577-1579
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• 2003

AlN thin films are prepared on Si (111) substrate by RF magnetron sputtering. Two-step deposition method is proposed to obtain AlN thin films with high c-axis (002)-TC value and low surface roughnesses. For all the deposited AlN films, the c-axis (002)-orientation, surface mophology, and roughness are characterized in terms of deposition conditions FEAR devices with Al/AlN/Mo/Si(111) configuration are also fabricated. From the frequency response characteristics, the return loss and electromechanical coupling contant($k_t{^2}$) are estimated.

• 한국정밀공학회지
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• 제16권3호통권96호
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• pp.9-17
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• 1999

This paper presents a method of grinding and polishing automation of precision die after CNC machining. The method employs a robot system equipped with a pneumatic spindle and a special abrasive film pad. The robot program is automatically generated off-line program form a PC and downloaded to robot controller. Position and orientation data for the program is supplied form cutter contact (CC) data of NC machining process. This eliminates separate robot teaching process. This paper aims at practical automation of die finishing process which is very time consuming and suffering from shortage of workpeople. Time loss due to changeover from one product to another is eliminated by PC off-line programming exploiting appropriate NC machining data. Dextrous 6-axis robot with rigid wrist and simple tooling enables the process applicable to larger, rather complex 3 dimensional free surfaces.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 1997년도 International Symposium on Fire Science and Technology
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• pp.77-84
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• 1997

Cone calorimeter measurements can be used for the calculation of effective material properties, which can be used as input parameters in modeling of fire. Main parameter measured in Cone calorimeter is heat release rate. Some other parameters as time to ignition, effective heat of combustion, mass loss rate or total heat released is also measured in Cone calorimeter. Total heat released is important from the point of view of total energy available in material in Fire situation. Cone calorimeter. measurements were done on several wood species (oak, beech, spruce, poplar). Measurements were provided at external irradiances 30, 50 and 65 ㎾/$m_2$ in horizontal orientation. Heat release rate data were evaluated and compared as a function of external irradiance for various species of wood. furthermore the influence of external irradiance on effective heat of combustion and total heat release was also evaluated for the period of flame combustion.

• 한국염색가공학회지
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• 제2권2호
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• pp.1-6
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• 1990

In order to investigate the fine structural changes of poly (ethylene terephthalate) film by hydrazinolysis, PET was treated with hydrazine hydrate in methanol at $30^{\circ}C$ for various times. Initially apparent crystallite size and degree of orientation are increased and then, gradually decreased with hydrazinolysis. According to thermoluminescence measurement, trap site decreased by dissolution and then gradually increased with growth of defect in structure. Maximum peak temperature of tan and dynamic loss modulus E" upon hydrazinolysis shifted to the lower temperature in the progress of hydrazinolysis.ysis.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.663-666
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• 2004

In this paper, we have investigated the structure and dielectric properties of the $(Ba_{0.6}Sr_{0.4})TiO_3$ (BST) thin films film fabricatedon MgO(100)/Si substrate by an alkoxide-based sol-gel method. Both the structure and morphology of films were analyzed by x-ray diffraction (XRD) and atomic force microscope (AFM). For the MgO(100)/Si substrates, the BST thin films exhibited highly (100) orientation. The highly (100)-oriented BST thin films showed high dielectric constant, tunability, and figure of merit (FOM). The dielectric constants, dielectric loss and tunability of the BST thin films annealed at 700 C deposited on the MgO(100)/Si substrates measured at 10 kHz were 515.9, 0.0082, and 54.3 %, respectively.

• Nuclear Engineering and Technology
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• 제53권11호
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• pp.3597-3611
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• 2021

The present paper studies the thermal-hydraulic behaviour of the rectangular supercritical natural circulation loop (SCNCL) using numerical model of one dimensional. Then the results of this model is confirmed with experimental and benchmark results. Variations with several geometric parameters like loop diameter, riser length, and heater length and operating conditions like heater inlet enthalpy, pressure, friction factor, and inlet and exit loss coefficient on steady-state performance are investigated for various orientations like HHHC, HHVC, VHVC and VHHC of the heater and cooler. The chances of existing static instability (Ledinegg excursion) has been investigated, which reveals that it can arise only in a low inlet enthalpy condition, far from the suggested various orientations of heater and cooler.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 춘계종합학술대회
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• pp.88-92
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• 2003

본 논문에서는 Al 하부전극 상에서 RF magnetron sputtering 기술을 이용한 ZnO 박막 증착 및 공정온도가 ZnO 결정성장에 미치는 영향을 고려하여 제작한 FBAR 소자에 대한 연구를 발표한다. 결과적으로, 20$0^{\circ}C$의 공정온도에서 주상형 결정립(columnar grain)을 가지고 c축 우선 배향된 ZnO 박막을 얻을 수 있었다. 이렇게 얻은 ZnO 박막을 FBAR 소자에 적용하여 제작한 결과, 2.05GHz의 공진 주파수에서 ~19.5dB의 반사손실을 보였다.

• 센서학회지
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• 제11권4호
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• pp.247-253
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• 2002

초전형 적외선 센서를 제작하기 위하여 rf 마그네트론 스퍼터링법으로 $(Pb,La)TiO_3(PLT)$/$LiTaO_3$(LTO)/PLT 강유전 박막을 증착한 후 급속 열처리하여 열처리 온도와 시간에 따른 결정성을 조사하였다. 강유전 박막의 c축 배향도에 따른 비유전율 및 유전손실을 측정하고 C축 배향도가 가장 큰 강유전 박막으로 제작된 센서에 대해 초전계수를 측정하여 센서의 전압응답에 대한 성능지수($F_V$)와 감도에 대한 성능지수($F_D$)를 구하였다. 얻어진 $F_V$, $F_D$는 각각 $6.15{\times}10^{-10}\;C{\cdot}cm/J$, $1.98{\times}10^{-8}\;C{\cdot}cm/J$였다.