Inductively coupled plasma reactive ion etching (ICP-RIE) of copper thin films patterned with SiO2 hard masks was carried out using piperidine/O2/Ar gas mixture. The etch rate, etch selectivity, and etch profile of copper thin films were investigated by varying gas concentration in piperidine/O2/Ar gas mixture. In addition, the etch parameters including ICP RF power, DC-bias voltage to substrate, and process pressure were varied to examine the etch characteristics. X-ray photoelectron spectroscopy and optical emission spectroscopy were employed to elucidate the etch mechanism under piperidine/O2/Ar gas chemistry. Finally, 150 nm-line patterned copper thin films were successfully etched using piperidine/ O2/Ar etch gas under the optimized etch conditions.
This study analyzed the change of electrical characteristics of a photocoupler when a narrow-band electromagnetic wave was combined with the photocoupler. A magnetron (3 kW, 2.45 GHz) was used as the narrow-band electromagnetic source. The EUT was Photocoupler (6N139) and the input signal was divided into two types: a square pulse and the second signal is 0 V. The malfunction of the photocoupler was confirmed by monitoring the variation in the output voltage of the photocoupler. As a result of the experiment, changes in the malfunctioning was observed as the electric field was increased. There are three types of malfunction modes: delay, output voltage off, and fluctuation. Bit errors were analyzed to verify the electrical characteristics of the photocoupler by narrow-band electromagnetic waves. The result of this study can be used as basic data for the effect analysis of photocoupler protection and impact analysis of high-power electromagnetic waves.
In this paper, the magnetization characteristics and the stored energy of magnetically coupled superconducting fault current limiter (SFCL)s using single and double high-Tc superconducting (HTSC) elements were compared. To analyze the magnetization characteristics and the stored energy, the magnetizing current and the flux linkage, which were derived from the electrical equivalent circuit of the SFCL using single and double HTSC elements, were calculated from the voltages and the current measured in the short-circuit tests. Through the comparative analysis on the magnetization characteristics and the stored energy for SFCL using sing and double HTSC elements, the magnetically coupled SFCL using double HTSC elements was shown to be more effective than the SFCL using single HTSC element from the point of view of the magnetic saturation.
In this study, we propose a novel fabrication of an oxide-based lateral thermoelectric pn couple and investigate the characteristics of the thermoelectric couple. Electrospun ZnO and LaSrCoO3 nanofibers are used as n- and p-legs of the couple, respectively. The Seebeck coefficients of the n- and p-type nanofibers and the pn couple are -98.1 μV/K, 42.4 μV/K, and 118.8 μV/K, respectively. The thermoelectric couple generates an output voltage of 484.7 μV at a temperature difference of 4.1 K.
In this study, in order to develop coupled vibration mode piezoelectric devices for Acoustic Emission(abbreviated as AE) sensor application with outstanding displacement and piezoelectric properties have been simulatedby ATILA FEM program. And, From the results of ATILA simulation, the AE sensor specimen, obtained superiorelectromechanical coupling factor and displacement, when the size of specimen is 3.45 mmΦ×3.45 mm with ratio ofdiameter/thickness(Φ/T)= 1.0. Therefore, AE sensor was fabricated by (Na,K,Li)(Nb,Ta) O3(abbreviated as NKL-NT)system piezoelectric ceramics using coupled vibration mode. The piezoelectric properties of NKL-NT ceramics wasexhibited that piezoelectric constant(d33), piezoelectric voltage constant(g33) and electro mechanical coupling factor(kp)have the excellent values of 261[pC/N], 40.10[10-3Vm/N], and 0.44, respectively. The manufactured piezoelectric devicewith ratio of Φ/T= 1.0 indicated the optimum values of resonant frequency(fr)= 556.5[kHz], antiresonant frequency(fa)=631.1[kHz], and effective electromechanical coupling factor(keff)= 0.473. The maximum sensitivity of the coupledvibration mode AE sensor was 55[dB] at the resonant frequency of 75[kHz]. The results show that the coupledvibration mode piezoelectric device is a promising candidate for the application AE sensor piezoelectric device.
In this paper, we carried out the investigations of both etch characteristics and mechanisms for the SnO2 thin films in O2/BCl3/Ar plasma. The dry etching characteristics of the SnO2 thin films was studied by varying the O2/BCl3/Ar gas mixing ratio. We determined the optimized process conditions that were as follows: a RF power of 700 W, a DC-bias voltage of -150 V, and a process pressure of 2 Pa. The maximum etch rate was 509.9 nm/min in O2/BCl3/Ar=(3:4:16 sccm) plasma. From XPS analysis, the etch mechanism of the SnO2 thin films in the O2/BCl3/Ar plasma can be identified as the ion-assisted chemical reaction while the role of ion bombardment includes the destruction of the metal-oxide bonds as well as the cleaning of the etched surface form the reaction products.
Performance of organic light-emitting diodes incorporating microlens array was simulated using a Light Tools software. Use of microlens array can help the light to escape out of the device. We simulated a reference device that is consisted of reflection layer, emissive layer, and flat transparent substrate. And in this reference device, outcoupled efficiency of 22% was obtained. Several shapes of microlens were applied such as hemisphere, trapezoid, cone, and rectangular parallelepiped. The results showed the improvement of outcoupled efficiency of the device with microlens compared to that of the reference one. And from the analyses of the simulated data, the obtained appropriate shape of microlens is hemisphere, and the improvement of the device with hemispherical lens is 57% higher than that of the reference one.
In this study, coupled mode piezoelectric devices for AE sensor application with excellent displacement and piezoelectric characteristics were simulated using ATILA FEM program, and then fabricated. Displacements and electromechanical coupling factors of the piezoelectric devices were investigated. The simulation results showed that excellent displacement and electromechanical coupling factor were obtained when the ratio of diameter/thickness was 1.0. The piezoelectric device of ф/T= 1.0 exhibited the optimum values of fr= 406 kHz, displacement= 6.11 × 10^-8[m], k_eff= 0.648. The results show that the coupled vibration mode piezoelectric device is a promising candidate for the application of AE sensor piezoelectric device.
The series connection-type superconducting fault current limiter (SFCL) with two magnetically coupled circuits was suggested and its effectiveness through the analysis on the current limiting and recovery characteristics was described. The fault current limiting characteristics of the proposed SFCL as well as the load voltage sag compensating characteristics according to the winding direction were investigated. To confirm the fault current limiting and the voltage sag suppressing characteristics of the this SFCL, the short-circuit tests for the simulated power system with the series connection-type SFCL were carried out. The series connection-type SFCL designed with the additive polarity winding was shown to perform more effective fault current limiting and load voltage sag compensating operations through the fast quench occurrence right after the fault appears and the fast recovery operation after the fault removes than that with the subtractive polarity winding.
In this paper, we propose useful load flow algorithms called FEDL (fast enhanced decoupled load flow). The proposed load flow method can improve the convergence characteristics particularly when the P-Q coupling becomes significant and the power system operating states deviate from the conditions required for stable convergence of the FDL by reflecting in part the effects of the off-diagonal terms in the Jacobian. In our test with IEEE AEP-30 bus system and RTS-96 73-bus system, it converge even when the fast decoupled load flow (FDL) and its variations keeping load flow matrices constant experience convergence problems. Test results show promising performances of the proposed algorithms in their convergence characteristics both in number of iterations and overall convergence speeds.
The etching characteristics of indium tin oxide (ITO) thin films in an O2/BCl3/Ar plasma were investigated. The etch rate of ITO thin films increased with increasing O2 content from 0 to 2 sccm in BCl3/Ar plasma, whereas that of ITO decreased with increasing O2 content from 2 sccm to 6 sccm in BCl3/Ar plasma. The maximum etch rate of 65.9 nm/m in for the ITO thin films was obtained at 2 sccm O2 addition. The etch conditions were the RF power of 500 W, the bias power of 200 W, the process pressure of 15 mTorr, and the substrate temperature of 40℃. The analysis of x-ray photo electron spectroscopy (XPS) was carried out to investigate the chemical reactions between the surfaces of ITO thin films and etch species.
Design of a Current-Transformer Based Inductive Coupler for Power-Line Communications Petrus A. Janse Van Rensburg, Bradley P. Watkins, Sanath Alahakoon IEEE Transactions on Power Delivery.2023; 38(3): 1788. CrossRef
Development of Communication Joint Tools for Implementing a Legacy-line Communication System in a Train Hyun Sik Kim, Soo Hoon Park, Seog Geun Kang Journal of the Korea Institute of Information and Communication Engineering.2015; 19(4): 877. CrossRef
A Powerline-based Legacy-line Communication System for Implementation of a Communication Network in Ship Hyun-Sik Kim, Seog Geun Kang Journal of the Korea Institute of Information and Communication Engineering.2015; 19(8): 1831. CrossRef
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