The electrical and mechanical properties of dielectric paper and cable at cryogenic temperature have been investigated to optimum insulating design of high-Tc superconducting(HTS) cable. From the results, Tensile strength of PPLP in liquid nitrogen was high more than that of air, but tensile strain could know that decrease sharply. According as tensile strength increases, the breakdown stress of PPLP in liquid nitrogen was decreased because PPLP was degradated. According as bending radius multiple is decrese, breakdown voltage decreased sharply. And bending radius multiple is thought that more than about 25 is suitable.

for many years already, testing laboratories, research institutes and manufactures try to find a reliable water tree accelerated ageing test that is able to show whether a polymer Medium Voltage cable os susceptible to water treeing or not. Test on laboratory samples, model cable designs, and fell size cable are presented. Apart form aging, another important aspect of any accelerated aging test is the right choice of th preconditioning method. THTS paper is the analysis of weibull distribution method after an accelerated aging test of MV(Medium Cable) cable.

As the integrated circuit device shrinks to the smaller dimension, the chemical mechanical polishing (CMP). process was required for the global planarization of inter-metal dielectric (IMD) layer with free-defect. However, as the IMD layer gets thinner, micro-scratches are becoming as major defects. Micro-scratches are generated by agglomerated slurry, solidified and attached slurry in pipe line of slurry supply system. It is well known that the presence of hard and larger size particles in the CMP slurries increases the defect density and surface roughness of the polished wafers. In this paper, we have studied. aging effect the of CMP slurry as a function of particle size. We prepared and compared the self-developed silica slurry by adding of abrasives before and after annealing. As our preliminary experiment results, we could be obtained the relatively stable slurry characteristics comparable to original silica slurry in the slurry aging effect.

Fault current limiters (FCL) are extensively needed to suppress fault currents, especially for trunk power systems heavily connected to high voltage/large current transmission lines. Due to its ideal electrical behavior, high-temperature superconductor fault current limiter (HTSFCL) becomes one of the most important developing trends of limiters in power system. This paper describes the result of an investigation of the dielectric characteristics of turn-to-turn insulation for pancake and solenoid type reactor coil in liquid nitrogen. The influence of thickness in a variety length, on AC, DC and impulse surface flashover has been investigated. Also, the relationships between the number of turn and breakdown characteristics were clarified. The information gathered in this test series should be helpful in the design of liquid nitrogen filled DC reactor type HTSFCL.

In the response to increasing the demands for electrical energy, much effort aimed to develop and commercialize 1MVA HTS power equipments that is supported by a grant from center for Applied Superconductivity Technology of the 21st Century Frontier R&D Program funded by the Ministry of Science and Technology is going on in Korea. For the development, the cryogenic insulation and winding insulation of it in this paper are discussed. In the first many types of dielectric insulating tests were carried out. In detail Breakdown characteristics of $LN_2$, FRP and turn insulating films, flashover characteristics along the FRP surface in $LN_2$ were verified after distinguishing insulation components in HIS windings. And then model windings were designed and insulation test was conducted. These included a AC withstand voltage test of 50kV rms and a lightning impulse test of 150kV at peak.

An ultrasonic motor is a motor which uses vibration -a type of elastic vibration- to obtain a driving force, which then drives the motor using friction. In this paper, mode conversion type - single resonance mode ultrasonic rotary motor that use langevin type ultrasonic vibrator was studied. This model was proposed for the first time by Japanese Kumada in 1985. In this study, finite element analysis (FEA) of a stator and bidirectional driving characteristic of a rotor was newly obtained. The amplitude and phase of displacement and elliptical trajectory of beam was confirmed by FEA The fabricated motor was operated to clockwise and counterclockwise in 40.8 [kHz] and 44.2 [kHz] respectively. But bidirectional driving characteristics did not coincide each other.

In order to get the infrared ray radiator with high efficiency emission, the starting raw material $Fe_2O_3$ powder is heat-treated under the oxygen pressure log[$PO_2$] = -13~15 at $800^{\circ}C$ for 2hours. It has shown that the radiation rate was larger than 0.85 at the relatively high temperature($400^{\circ}C$), and decreased slowly with increasing the temperature from 50 to $400^{\circ}C$.

($Ba_{0.6-x}Sr_{0.4}Ca_x)TiO_3$ (BSCT) (x=0.10, 0.15, 0.20) powder, prepared by the sol-gel method, were mixed with organic vehicle and the BSCT thick films were fabricated by the screen-printing techniques on alumina substrates using the BSCT paste. The structural and the electrical properties were investigated for various composition ratio and sintering temperature. BSCT thick film thickness, obtained by four printings, was approximately 110 ~ 120 ${\mu}m$. The Curie temperature and dielectric constant at room temperature were decreased with increasing Ca content. The relative dielectric constant, dielectric loss and tunability of the BSCT(50/40/10) specimen, which was sintered at $1420^{\circ}C$ and measured at 1MHz, were about 910, 0.46% and 9.28% at 5kV/cm, respectively.

In this paper, we investigated the electric and acoustic properties of piezoelectric composites, which were fabricated using polymer and piezoelectric ceramics, when the volume fraction of PZT varies. Practically, the shrinkage rate of polymer is an important factor in ultrasonic transducer fabrication. When 10 wt% filler A was added into polymer(Epofix), the lowest shrinkage was resulted. The electromechanical coupling factor($k_t$) of the fabricated piezoelectric composites showed its highest when the volume fraction PZT was 0.6. It decreased if the volume fraction was higher than the value. The relative permittivity and acoustic impedance of piezoelectric composites decreased linearly when PZT volume fraction was decreased. The lowest acoustic impedance was 3.2 when the volume fraction of PZT was 0.2.

텅스텐브론즈 세라믹스의 결정구조는 산소 팔면체를 뼈대로 각각 다른 형태의 A, C, B 양이온 자리로 이루어져 있다. A, C의 양이온 자리는 알카리 이온 또는 알카리 토금속 이온으로 채워지며, B 자리는 Nb 또는 Ta 이온으로 채워지게 된다. 이 중 A와 C 자리가 채워지는 정도로 unfilled, filled, completely filled 텅스텐브론즈로 나누어지게 된다. completely filled 텅스텐브론즈의 대표적인 물질인 $K_3Li_2Nb_5O_{15}$(KLN)는 전광특성, 비선형 광학특성으로 인하여 다양한 광소자로의 응용과 압전 특성, 초전 특성을 이용한 압전 소자로의 응용이 가능한 재료로 보고되고 있다. 하지만 이러한 꽉 찬 결정구조로 인하여 KLN의 경우 한정된 고용영역을 가지고 있어 물리적 성질의 변화가 제한되어 있는데, 이를 극복하기 위한 여러 가지 시도가 있었다. 이 중 A 자리와 C 자리를 치환하는 연구는 많이 알려져 있으나 치환시 빈 자리를 수반하는 경우가 대부분이다. 반면, B 자리를 치환하는 연구는 Nb를 Ta로 치환하는 경우가 알려져 있는데 이 경우 결정내에 빈자리가 생성되지 않는다. 이들 연구는 모두 단결정의 경우에 국한되어 있으며 단결정 제조시에는 조성을 정확히 조정하기 어렵고, 냉각시 crack이 발생하는 등의 문제를 가지고 있어 그 응용이 제한되고 있다. 따라서 본 연구에서는 KLN 다결정 세라믹스에서 Nb를 Ta으로 치환하여 치환에 따른 상변화와 치밀화 거동, 그리고 이에 따른 전기적 특성을 조사하여 이들 간의 상관관계를 조사하였다.

In this paper, the electric field distribution in dielectric tube with one layer and spherical dielectric(glass) in water was simulated. The reactor was made up of the spherical dielectric that is diameter : 3.0[mm], glass(${\varepsilon}_r$:5) and one glass plate of thickness(2[mm]), ${\varepsilon}_r$(5) as electrode. The discharge gap was 8[mm). Toget more strong electric field, the dielectric constant should be higher comparatively. Using the spherical dielectric for water discharge in dielectric tube, the location of equipotential line was shifting from the interior to the exterior. At real water discharge experimental, $H_2O_2$ was measured higher generated $H_2O_2$ in water at condition of water rate(1[l/min]) and injector than condition of non-injector or 2-3[l/min])

In this paper, the electric field distribution in dielectric tube with one layer and spherical dielectric($ZrO_2$) in water was simulated. The reactor was made up of the spherical dielectric that is diameter : 3.0[mm], $ZrO_2(\varepsilon_r:10)$ and one glass plate of thickness(2[mm]), $\varepsilon_r$(10) as electrode. The discharge gap was 8[mm]. To get more strong electric field, the dielectric constant should be higher comparatively. Using the spherical dielectric for water discharge in dielectric tube, the location of equipotential line was shifting from the interior to the exterior. At real water discharge experimental, ozone was measured higher dissolved ozone in water at condition of water rate(l[l/min]) and injector than condition of non-injector or 2~3[l/min].

Low melting crystalline solder glasses for CRT sealing were prepared from the composition of PbO 73.0~75.5 wt%, ZnO 12~15 wt%, $B_2O_3$ 7.0~9.0 wt%, BaO 1.5~3.5 wt%, $P_2O_5$ 1.0~2.5 wt%, $Bi_2O_3$ 0.5~20 wt%. The nucleation and crystallization of the crystalline solder glasses were studied by DTA, SEM and XRD. $2PbO{\cdot}ZnO{\cdot}B_2O_3$ crystalline phase was formed from glass matrix by heat-treatment of glass frits Crystalline solder glasses developed from this paper have good firing condition of $430{\sim}440^{\circ}C$ for 10min and good physical properties

IPMSM (Interior Permanent Magnet Synchronous Motor) is widely used in many applications such as an electric vehicle, compressor drives of air conditioner and machine tool spindle drives. In order to maximize the efficiency in such applications, this paper is proposed the optimal control method of the armature current. The controllable electrical loss which consists of the copper loss and the iron loss can be minimized by the optimal control of the armature current. The minimization of loss is possible to realize efficiency optimization control for the proposed IPMSM The proposed control algorithm is applied to IPMSM drive system, the operating characteristics controlled by efficiency optimization control are examined in detail by simulation.

Our Zn diffusion into n-type $GaAs_{0.60}P_{0.40}$ used ampoule-tube method to increase IV. N-type epitaxial wafers were preferred by $H_2SO_4$-based pre-treatment. $SiO_2$ thin film was deposited by PECVD for some wafers. Diffusion times and diffusion temperatures respectability are 1, 2, 3 hr and 775, $805^{\circ}C$. LED chips were fabricated by the diffused wafers at Fab. The peak wavelength of all chips showed about 625~650 nm and red color. The highest IV is about 270 mcd at the diffusion condition of $775^{\circ}C$, 3h for the wafers which didn't deposit $SiO_2$ thin films. Also, the longer diffusion time is the higher IV for the wafers which deposit $SiO_2$ thin films.

To diffuse Zn at solid-state, the $SiO-2$/ZnO/$SiO_2$ wafers was made by PECVD and RF Sputter. Thicknesses of bottom $SiO_2$ and cap $SiO_2$ was about 500 ${\AA}$ and about 3500 ${\AA}$. Diffusion temperatures were $760^{\circ}C$, $780^{\circ}C$, and $800^{circ}C$, and diffusion times were 1, 2, 3, 4, 5, and 6 hr. LED chips were fabricated by the diffused wafers at Fab. The peak wavelength of all chips showed about 625~650 nm and red color. Main reason for Iv change was by diffusion temperature not diffusion time. The lower temperature was the higher Iv. We thick that these properties is because of the very high diffusion temperature.

One of the most important problems in ADS method is that the method has too long addressing period, The addressing time can be defined as the sum of the discharge time lag and the duration of discharge current. If the addressing time increases, the sustaining period for display image should be decreased. As a result, the luminance of the PDP decreases. Therefore, the discharge time lag and duration of discharge current should be decreased in order to reduce the addressing time. In this paper, in order to improve addressing time, relationships between addressing time and cell structure in AC PDP was studied

Effects of delay and panel temperature on the discharge time lag and the controllability of weak discharge mode were studied under single cell driving circumstances of ac PDP. It was found that sufficient number of priming particle is necessary for inducing weak discharge in ramp voltage driving. Discharge time lag was reduced dramatically under elevated panel temperature condition It is speculated that decrement of discharge time lag at the high temperature is related to the reduction of diffusion loss of charged particles during the after glow.

Recently as new digital media like High Definition Television (HDTV) have been made popularization. However In case of image quality characteristics of AC PDP, the problem especially raised is 'image sticking' phenomenon, the phenomenon that the previously displayed pattern still remains after the image in realizing high picture quality. In this paper, Image sticking Phenomena observed in AC PDP are defined and classified, these effects are analyzed as luminance, color purity through chromaticity diagram and firing voltage state using light waveform.

Conductive polyaniline(PANI)-camphosulfonic acid (CSA) film applied as a hole injection layer in ITO/PANI/P3HT/LiF/Al device. In the AFM images, electrochemically polymerized PANI-CSA films have the small particles and smooth sufficient for application as hole injection layer. By insertion of PANI-CSA buffer layer, the turn on voltage of ITO/PANI/P3HT/LiF/Al device lowed by 3V, whereas that of ITO/P3HT/LiF/Al device shows 5V.

$Sr_xBa_{1-x}Nb_2O_6$(SBN, $025{\leq}x{\leq}0.75$) ceramic is a ferroelectric material with tetragonal tungsten bronze (TTB) type structure, which has a high pyroelectric coefficient and a nonlinear electro-optic coefficient value. In spite of its advantages, SBN has not been investigated well compared to other ferroelectric materials with perovskite structure. In this study, SBN thin film was manufactured by ion beam sputtering technique using the prepared SBN target in Ar/$O_2$ atmosphere. SBN30 thin film of 500 ${\AA}$ was pre-deposited as a seed layer on Pt(l00)/$TiO_2$/$SiO_2$/Si substrate followed by SBN60 deposition up to 4500 ${\AA}$ in thickness. SBN60/SBN30 layer was deposited at different Oxygen amount of 0, 8.1, 17, and 31.8 sccm, respectively. The crystallinity and orientation behavior as well as electric properties of SBN60/SBN30 multi-layer were examined. The deposited layer was uniform and the orientation was shown primarily along (001) plane from XRD pattern. The crystal structure and the electric properties depended on the Oxygen amount, heating temperature and was the best at O2 = 8.1 seem, $750^{\circ}C$. In electric properties of Pt/SBN60/SBN30/Pt thin film capacitor prepared, the remnant polarization (2Pr) value was 13 ${\mu}C/cm^2$, the coercive field (Ec) 75 kV/cm, and the dielectric constant 1492, respectively.

ITO thin films were deposited by RF-magnetron sputtering method and crystallization behavior of the films with and without external heating as a function of deposition time was examined. X-ray diffraction results indicated an amorphous state of the film when the deposition time is short about 10 min. When the deposition time was increased over 20 min development of crystallization of the films is observed. Because RF-sputtering transfers the high-energy to the growing film by energetic bombardment, it is believed that considerable activation energy for the crystallization of the film has transferred during deposition, which resulted in the crystallization of ITO thin films without external energy supply.

Photoluminescence(PL) properties of Silicon nanocrystals (nc-Si) as a function of temperature is reported to consider the mechanism of PL. Nc-Si has been made by $Si^+$ ion-implantation into thermal $SiO_2$ and subsequent annealing. And after gold had been diffused at the same samples above, the resultant PL spectra has been compared to the PL spectra from the non-gold doped nc-Si. PL peak energy variation from nc-Si is same with the variation of energy bandgap of bulk silicon as temperature changes from 6 K to room temperature. This result may mean nc-Si is still indirect transition material like bulk silicon. Gold doped nc-Si reveals short peak wavelength of PL spectrum than gold undoped one. PL peak shift through gold doing process shows clearly the PL mechanism is not from defect or interface states. PL intensity increases from 6K to a certain temperature and then decrease to room temperature. This characteristic with temperature shows that phonon have a role for the luminescence as theory explains that electron and hole can be recombined radiatively by phonon's assist in nc-Si, which is almost impossible in bulk silicon. Therefore luminescence is observed in nc-Si constructed less than a few of unit cell and the peak energy of luminescence can be higher than the bulk bandgap energy by the bandgap widening effect occurs in nanostructure.

This study uses ZnO thin film as a piezoelectric material and Pt as bottom electrode for FBAR (film bulk acoustic resonator) device. ZnO thin film and Pt were deposited by RF-magnetron sputtering method. ZnO thin film and Pt were oriented to c-axis. Top electrode Al was deposited by thermal evaporation. The membrane was formed of bulk micromachining. The FBAR was evaluated by XRD, SEM and electrical characterization. The resonant frequency was measured by HP 8753C Network Analyzer. A fabricated FBAR device exhibited a resonant frequency of 700 MHz ~ 1.5 GHz. When bottom electrode and top electrode thickness were fixed, the resonant frequency was increased as decreasing ZnO thin film thickness.

$Ba_2NaNb_5O_{15}$, hereafter BNN, thin films are attractive candidates for nonvolatile memory and electro-optic devices. In the present work, thin films that have different contents of Ba, Na and Nb have been prepared by H-MOD technique on silicon and Pt substrates. XRD and SEM were used to investigate the phase evolution behavior and the microstructure of the films. It was found that the films of about 450nm thick were crack-free and uniform in microstructure. Nb content strongly influenced the phase formation of the films, where low temperature phase was always formed at the stoichiometric BNN composition. However, the amount of low temperature phase decreased with the increase of excess Nb content, and the single phase (orthorhombic tungsten bronze structure) BNN thin film was obtained at the temperature as low as $750^{\circ}C$ for samples with excess niobium. From this study, the sub-solidus phase diagram below $850^{\circ}C$ for $BaO-Na_2O-Nb_2O_5$ ternary system is proposed.

In this study, an ultrasonic transducer is fabricated with 1-3 type composite resonators. Pulse-echo responses of an ultrasonic transducer are investigated in underwater dependent on the variable designated water-level. LED Output signals of a level limit with changing a water level is obtained by the 1-3 type self-made composite transducer and electric measuring unit. LED is turned on at above the up-limit level with increasing a water level, and LED is turned on at less than the down-limit level with decreasing a water level. There was good agreement between the virtual water level and output LED signal by using the self-made water-detecting system.

The magnetostriction of FeCoGe/phenol composites is measured under the external magnetic field. A few Measurement are carried out by using the electrical-resistance strain gage, the Wheaton Bridge for eliminating the unnecessary voltage, the lock-in-amplifier for the signal amplification and noise filtering. When the external magnetic field is applied to the longitudinal direction against those samples which is the 10wt.% phenol in composites, the theoretical maximum strain of 120ppm is obtained. According to the larger strain than that of others solid state actuators and piezoelectric actuators. FeCoGe/phenol composites could be useful as an actuator.

We report herein synthetic results obtained six new types of bis-benzocrown ethers containing imine group. Bis crown ethers l~3 are aminobenzo-15-crown-5-ether linked with terephthalaldehyde, isophthalaldehyde, phthaldehyde respectively by imine reaction. Bis crown ethers l~3 are different distances in each crown ether rings. Bis crown ether 4 has large cavity in crown ethers. Functionalized crown ether 5 is synthesized amonobenzo-l5-crown-5-ether and terephthaladehyde same ratio at one to one. Bis crown ether 6 has phothosensitive linkage between crown ethers. Bis crown ether 7 is prepared by amonobenzo-l5-crown-5-ether and triethyl ortho formate. 4'-Nitrobenzo-crown ethers and 3',4'-dinitrobenzo-crown ethers were prepared by nitration of benzo crown ethers, obtained from the reaction of catechol and oligoethylene glycol ditosylate. Crown ethers containing aldehyde group were synthesized from the reaction of 3,4-dihydroxybenzaldehyde and corresponding ditosylate respectively. The synthesized crown ethers were characterized respectively by IR, NMR. GC-Mass.

Fractal mathematics is being highlighted as a research method for classification of image. But the application of Fractal dimension(FD) has been required the complicated calculation method because of its complex repetition progressing. In this paper, it has been developed the new approach method to express the Fractal Dimension(FD) for aging level calculation and estimation system of outside insulator using special image processing algorithm. As a result after FD testing, the recognized aging estimation of FD has a very characteristics compared to the conventional visual inspection.

Time-resolved photoluminescence from InGaN/GaN multi-quantum well structures was investigated for two different shapes of square- and trapezoidal wells grown by metal-organic chemical vapor deposition. To compare to the conventional square well structure with a radiative recombination lifetime of 0.170 nsec, the large value of lifetime of 0.540 nsec from trapezoidal well were found at room temperature. This value is similar to the value for GaN host material indicating no confinement effect of quantum well. Furthermore, the high resolution transmission electron microscopy image provides the In clustering effect in the trapezoidal well structure.

The electrical properties of a ZnO-based multilayered chip varistor (abbreviated as MLV) were studied as functions of firing condition and the degree of lamination. The fundamental varistor characteristics such as nonlinear coefficient and breakdown voltage were independent of the degree of lamination. As the number of the laminated ceramic sheets increased, however, not only the energy handling capability but also the capacitance and the leakage current which are relevant to delayed response to the voltage surge and the pre-breakdown energy loss, respectively, increased. With the increase of firing temperature between $950^{\circ}C$ and $1150^{\circ}C$, both the capacitance and the leakage current of the MLV increased due mainly to the grain growth of ZnO and the volatilization of $BiO_2O_3$. High performance MLVs with clear electrode pattern were obtained at the firing temperature range of $l000{\sim}1050^{\circ}C$ in this experiment.

ALD(Atomic Layer Deposition) 법으로 박막 알루미나를 형성한 후 웨이퍼 접합과 박막화 공정으로 알루미나를 매몰절연막으로 하는 SOI 구조를 제조하고 그 특성을 조사하였다. 알루미나 박막의 유전 특성과 실리콘과의 계면 특성은 C-V 측정으로, 단면 분석은 SEM(Scanning Electron Microscope) 촬영으로 조사하였다. 알루미나와 실리콘을 접합하기 위하여 1100C에서 열처리를 행한 후 알루미나와 실리콘의 계면 상태 밀도는 $2.5{\times}10^{11}/cm^2-eV$였다. 그리고 SEM의 단연 분석과 AES(Auger Electron Spectroscope)의 깊이 방향 분석을 통해서 매몰 알루미나층의 존재를 확인하였다. 알루미나는 실리콘 산화막보다 높은 열전도성을 가지므로 이를 매몰절연막으로 하여 SOI 구조를 제조하면 기존의 실리콘산화막을 매몰절연막으로 하는 SOI를 기판으로 하여 제조되는 소자보다 selg heating 효과가 감소된 우수한 특성의 소자를 제조할 수 있다.

New porphyrin square (1) was prepared by reaction of porphyrin containing pyridine and $Re(CO)_5Cl$ in THF/toluene solvent. 2-(Methylenel5-crown-5)-nicotinoly ester(2) was synthesized by reaction of 2-(Hydroxymethyl-15-crown-5 and nicotinoly chloride in $CH_2Cl_2$. In fluorescence quenching studies luminescence was quenched by addition of the guest(2) into host(l). In the host-guest system we could obtain binding constant (K=$1.13{\times}10^7M^{-1}$) at decreasing concentration of (2). But the luminescence was dramatically increased after $Na^+$ was added into the host-guest system.