The proposed stretchable transparent electrodes based on silver nanowires (AgNWs) were prepared on a polyurethane (PU) substrate. In order toavoid the surface roughness caused by the silver nanowires, a titanium oxide (TiO₂) buffer layer was addedby coating and heating the organometallic sol-gel solution. The fabricated stretchable electrodes showedan electrical sheet resistance of 24 Ωsq^-1, 78% transmittance at 550 nm, and an average surface roughness below 5 nm. Furthermore, the AgNW-based electrode maintained its initial electrical resistance under 130% strain testing conditions, without the assistance of additional conductive polymer layers. In this paper, the critical role of the TiO₂ buffer layer between the AgNW network and the PU substrate has been discussed.

This study investigated the various physical and electrical effects of silicon direct bonding. Direct bonding means the joining of two wafers together without an intermediate layer. If the surfaces are flat, and made clean and smooth using HF treatment to remove the native oxide layer, they can stick together when brought into contact and form a weak bond depending on the physical forces at room temperature. An IR camera and acoustic systems were used to analyze the voids and bonding conditions in an interface layer during bonding experiments. The I-V and C-V characteristics are also reported herein. The capacitance values for a range of frequencies were measured using a LCR meter. Direct wafer bonding of silicon is a simple method to fuse two wafers together; however, it is difficult to achieve perfect bonding of the two wafers. The direct bonding technology can be used for MEMS and other applications in three-dimensional integrated circuits and special devices.

ZnS was chemically deposited as a buffer layer alternative to CdS, for use as a Cd-free buffer layer in Cu(In_1-xGa_x)Se₂ (CIGS) solar cells. The deposition of a thin film of ZnS was carried out by chemical bath deposition, following which the structural and optical properties of the ZnS layer were studied. For the experiments, zinc sulfate hepta-hydrate (ZnSO₄·7H₂O), thiourea (SC(NH₂)₂), and ammonia (NH₄OH) were used as the reacting agents. The mole concentrations of ZnSO₄ and SC(NH₂)₂ were fixed at 0.03 M and 0.8 M, respectively, while that of ammonia, which acts as a complexing agent, was varied from 0.3 M to 3.5 M. By varying the mole concentration of ammonia, optimal values for parameters like optical transmission, deposition rate, and surface morphology were determined. For the fixed mole concentrations of 0.03 M ZnSO₄·7H₂O and 0.8 M SC(NH₂)₂, it was established that 3.0 M of ammonia could provide optimal values of the deposition rate (5.5 nm/min), average optical transmittance (81%), and energy band gap (3.81 eV), rendering the chemically deposited ZnS suitable for use as a Cd-free buffer layer in CIGS solar cells.

The degradation mechanism of Mo_xW_1-xSi₂ ultrahigh-temperature heating elements fabricated by selfpropagating high-temperature synthesiswas investigated. The Mo_xW_1-xSi₂ specimens (with and without post-annealing) were subjected to ADTs (accelerated degradation tests) at temperatures up to 1,700℃ at heating rates of 3, 4, 5, 7, and 14℃/min. The surface loads of all the specimen heaters were increased with the increase in the target temperature. For the Mo_xW_1-xSi₂ specimens without annealing, many pores and secondary-phase particles were observed in the microstructure; the surface load increased to 23.9 W/㎠ at 1,700℃, while the bending strength drastically reduced to 242 MPa. In contrast, the Mo_xW_1-xSi₂ specimens after post-annealing retained single- Mo_xW_1-xSi₂ phases and showed superior durability after the ADT. Consequently, it is thought that the formation of microcracks and coarse secondary phases during the ADT are the main causes for the degraded performance of the Mo_xW_1-xSi₂ heating elements without post-annealing.

In this study, (1-x)(Na_0.52K_0.443Li_0.037)(Nb_0.883Sb_0.08Ta_0.037)O₃-x(Bi_0.5(Na_0.7K_0.3)_0.5ZrO₃ ceramics were fabricated by BNKZ substitution using a conventional solid-state method to develop excellent lead-free piezoelectric ceramics for piezoelectric actuators; their dielectric and piezoelectric properties were then investigated. All specimens were in the orthorhombic phase. NKL-NSTO₃ ceramics with x=0.01 showed excellent piezoelectric properties. The density (ρ), piezoelectric charge constant (d₃₃), planar piezoelectric coupling coefficient (k_p), mechanical quality factor (Q_m), and dielectric constant (ε_r) had optimized values of 4.56 g/㎤, 208 pC/N, 0.43, 96, and 975, respectively.

In this study, an epoxy insulation barrier for high voltage GIS was developed using epoxy and a filler with a Young`s modulus of 11 GPa. The material was investigated using a simulation of the principal stress, displacement, and safety factors while optimizing the profile shape. The simulation showed that thelarger Young`s modulus of the Al₂O₃ filler compared to the SiO₂ in the epoxy insulation can contribute to an increase in resistance to mechanical fracturing for theoptimized profile barrier in high voltage GIS. In addition, the safety factor was improved by 10%. It can be concluded that the mechanical fracturing properties of the insulation barrier can be enhanced by increasing the content of the elastic filler, Al₂O₃, for high voltage GIS applications.

We have evaluated the ferroelectric and electrical properties of pure BiFeO₃ (BFO) and Bi_0.9A_0.1Fe_0.975V_0.025O_3+α(A=Nd, Tb) thin films on Pt(111)/Ti/SiO₂/Si(100) substrates by using a chemical solution deposition method. The remnant polarization (2P_r) of the Bi_0.9Tb_0.1Fe_0.975V_0.025O_3+α (BTFVO) thin film was approximately 65 μC/㎠, with a maximum applied electric field of 950 kV/cm and a frequency of 10 kHz, where as that of the Bi_0.9Nd_0.1Fe_0.975V_0.025O_3+α (BNFVO) thin film was approximately 37 μC/㎠ with a maximum applied electric field of 910 kV/cm. The leakage current density of the co-doped BNFVO thin film was four orders of magnitude lower than that of the pure BFO thin film, at 2.75×10^-7 A/㎠ with an applied electric field of 100 kV/cm. The grain size and uniformity of the co-doped BNFVO and BTFVO thin films were improved, in comparison to the pure BFO thin film, through structural modificationsdue to the co-doping with Nd and Tb.

This work reports the surface morphology and transmittance of copper oxide thin films for semitransparent solar cell applications. We prepared the oxide specimens by subjecting copper thin films to an oxidation reaction at annealing temperatures ranging between 100℃ and 300℃. The color of the as-deposited specimen was red, but changed to purple at the annealing temperature of 300℃. The surface morphology and transmittance of the specimens were significantly dependent on the annealing temperature and thickness of the copper films. Copper oxide nanoparticles prepared from a 20-nm-thick copper film at an annealing temperature of 300℃ provided a maximum transmittance of 93%. The obtained optical characteristics and surface morphology suggest that copper oxide thin films prepared by an oxidation reaction can be potentially employed as color- and transmittance-adjusting layer in semitransparent thin solar cells.

This paper presents the design and fabrication of a high power piezoelectric ultrasonic surgery unit for multi-purpose dental implantation. A conventional piezoelectric ultrasonic surgery units consists of a transducer and a tip. However, the drawback of this simple structure is that the output performance of the transducer considerably changes with the change of the tips. An ultrasonic surgery unit that has an additional booster between the transducer and the tip can solve this problem to some extent; for this, an optimal structural design for the transducer is required. We used the Bolted Langevin Transducer (BLT) as the basic transducer; it consists of piezoelectric ceramics and a metal body. It`s structure was optimized using mathematical methods to determine the length and radius of the tail and head masses. Additionally, the booster was also subjected to the same methods. Using these mathematical methods, optimal results in terms of the resonance frequency (24.96 kHz), displacement (14.27 ㎛), and pressure (2.8 MPa), could be obtained. The validity of this proposed surgery unit was confirmed experimentally, exhibiting a cutting force of around 7% higher than that of a conventional surgery unit.

Herein, we report the fabrication of low-voltage N-type organic field-effect transistors by using high capacitance fluorinated polymer gate dielectrics such as P(VDF-TrFE), P(VDF-TrFE-CTFE), and P(VDF-TrFE-CFE). Electronwithdrawing functional groups in PVDF-based polymers typically cause the depletion of negative charge carriers and a high contact resistance in N-channel organic semiconductors. Therefore, we incorporated intermediate layers of a low-k polymerto prevent the formation of a direct interface between PVDF-based gate insulators and the semiconducting active layer. Consequently, electron depletion is inhibited, and the high charge resistance between the semiconductor and source/drain electrodes is remarkably improved by the in corporation of solution-processed charge injection layers.

Electrical energy is playing an increasingly vital role as the primary energy source in everyday life. With the increase in electric power consumption, power facilities are under an increasing stress and must operate at a high capacity. Consequently, the demand for electric power cables in power transmission and distribution lines is rapidly increasing. Underground distribution lines have been steadily replacing the aboveground lines owing to the increase in electric power demand and the need to increase the supply voltage. In addition to line damage, worker safety is of primary concern in this type of underground infrastructure.In this study, to improve the safety of workers dealing with underground transmission lines, we analyzed the electromagnetic field generated around the distribution line and determined the basic criteria for developing a device that can detect a live underground line.

Lamination is used extensively in various industries. The type of lamination applied to the material depends on the precision level required, which varies for materials needed for everyday use, materials used in high-tech industries, and processes employed to fabricate finished products. Especially in hot lamination, the distribution of the surface temperature of the heating roller is very important to avoid the generation of internal bubbles and ensure flatness of the attached materials, and thus maintain a good standard of quality and productivity. In this study, we have developed a system to monitor the surface temperature of the heating rollerby applying a heterogeneous controller and a non - contact temperature sensor. This monitoring system accurately measures the surface temperature of the heating roller and applies the RS485 MODBUS communication method for easy expansion. Using this system, a laminated prototype was fabricated, and its efficacy for non-contact temperature sensor calibration, Ethernet IP communication, stoppage of the heating roller, and determination of temperature distribution with rotation was examined for its potential usage in industries.