Ceramic powder is an important material used for various purposes in advanced industries, and the fundamental properties of ceramic powder such as particle size, particle size distribution, and flow properties play a decisive role in determining the quality and performance of the final product. In general, these properties have been evaluated through particle size and shape analysis. However, these methods have limitations in providing a comprehensive understanding phenomena related to powder flow, coagulation, and wear. Consequently, performance evaluation based on the analysis of powder flow properties has been increasingly adopted. Previously, flow properties were primarily assessed using funnel-based methods. However, these methods have limitations, as they are challenging to apply to powders smaller than a few micrometers or those with strong coagulation tendencies, and they also suffer from low reliability. To address these issues, this paper introduces a novel piece of equipment that measures flow properties using image analysis and presents various parameters for static and dynamic flow behavior based on this technique. The proposed equipment offers exceptional versatility, as it can be applied to all types of ceramic powders regardless of their size or shape. The principles and measurement methods of the equipment are demonstrated through static and dynamic image analysis of ceramic powders with varying sizes and shapes used as examples.

The 4H-SiC VDMOSFET demonstrates a high reverse breakdown voltage (BV) due to the JFET region but experiences relatively high on-resistance (R_on). A widely adopted method to reduce the R_on is to uniformly increase the doping concentration of the JFET region, which results in a trade-off that reduces the BV. This study proposes a method to optimize the segmentation of the JFET region by selectively increasing the doping concentration using ‘total doping’, ‘half-doping’, and ‘quarter-doping’. The optimized quarter segment with a specific doping concentration slightly reduces BV, but the sharp decrease in specific on-resistance (R_on,sp) results in a 105% improvement in the performance index, Baliga’s Figure of Merit (BFOM). This research suggests the potential for electrically superior designs by modifying the doping concentration in the JFET region of conventional VDMOSFET structures.

Various process modifications have been used to minimize SiO₂ gate oxide aging in metal-oxide-semiconductor field-effect transistors (MOSFETs). In particular, post-metallization annealing (PMA) with a deuterium ambient can effectively eliminate both bulk traps and interface traps in the gate oxide. However, even with the use of PMA, it remains difficult to prevent high levels of radiation-induced gate oxide damage such as total ionizing dose (TID) during long-term missions. In this context, additional low-temperature heat treatment (LTHT) is proposed to recover from radiation-induced damage. Positive traps in the damaged gate oxide can be neutralized using LTHT, thereby prolonging device reliability in harsh radioactive environments.

Climate conditions, especially transport and storage, are a very important factor in the process of sampling and testing insulation oil in the field. The samples of insulating oil exposed to the atmosphere affect the dielectric strength, total acid number and moisture test value by oxygen and high humidity environment and may also affect the results according to the criteria specified in each test. Therefore, reliable test values for insulating oil testing require consideration of the atmospheric environment of the test site, including oxygen and humidity. In this paper, each test was conducted on insulating oil exposed to various time and humidity environments, and the effect of the atmospheric environment on the test results was analyzed by comparing and analyzing with the first insulating oil.

In line with the development of electronic devices and technologies, the demand for improving ferroelectric materials’ performance is increasing. Since K_0.5Na_0.5NbO₃ (KNN), an eco-friendly ferroelectric material that does not use lead and has a high Curie temperature, it is attracting attention to its usability as a high-temperature dielectric, and various studies are being conducted to increase performance. In a KNN having a perovskite structure, there was a simulation result that the KNN has higher spontaneous polarization when the A-site in which sodium ions exist is replaced with lithium ions. If the simulation results can be proven experimentally, the application range of KNN-based ferroelectric materials will increase. To this end, we tried to manufacture a K_1-xLi_xNbO₃ (KLN) with high electrical characteristics by fabricating niobium-deficient and potassium-excessive compositions, which attempt was made to solve the stoichiometry problem by volatilization and suppress secondary phases. If KLN’s secondary phase suppression and relative permittivity improvement are successful, it will contribute to meeting the demand for developing electronic devices.

A triboelectric nanogenerator is a promising energy harvester operated by the combined mechanism of electrostatic induction and contact electrification. It has attracting attention as eco-friendly and sustainable energy generators by harvesting wasting mechanical energies. However, the power generated in the natural environment is accompanied by low frequencies, so that the output power under such input conditions is normally insufficient amount for a variety of industrial applications. In this study, we introduce a non-contact rotational triboelectric nanogenerator using pedaling and gear systems (called by P-TENG), which has a mechanism that produces high power by using rack gear and pinion gear when a large force by a pedal is given. We design the system can rotate the shaft to which the rotor is connected through the conversion of vertical motion to rotational motion between the rack gear and the pinion gear. Furthermore, the system controls the one directional rotation due to the engagement rotation of the two pinion gears and the one-way needle roller bearing. The TENG with a 2 mm gap between the rotor and the stator produces about the power of 200 __ and turns on 82 LEDs under the condition of 800 rpm. We expect that P-TENG can be used in a variety of applications such as operating portable electronics or sterilizing contaminated water.

The rod-shaped Ni_0.5Zn_0.5Fe₂O₄ particles were synthesized via a topotactic reaction, in which goethite (α-FeOOH) particles are the main constituents. The phases, microstructures and magnetic properties of these particles were studied using XRD, FE-SEM and VSM. The precursor solution consisted of NiSO₄·xH₂O, ZnSO₄·xH₂O, goethite and D.I. water werereacted at four different temperatures (50, 70, 90, 100℃) to generate four differently precipitated particles respectively. During the co-precipitation reaction, the pH of the solution was maintained at 8.0 using NaOH. The particles coprecipitated and calcined at a temperature of 700℃, exhibited a rod-shape similar to its original goethite, which means that the shape of Ni-Zn ferrite particles can be topotactically controlled by the goethite. The particles synthesized at 70 and 90℃ have a saturation magnetization of 29 and 35 emu/g respectively; representing better values than the ones synthesized at the 50 and 100℃, in which some second phases such as Fe₂O₃ were observed.

Thermal batteries are used in military power sources that require robustness and long storage life for applications in missiles and torpedoes. FeS₂ powder is currently used as a cathode material because of its high specific energy density, environmental non-toxicity, and low cost. MS₂ (M = Fe, Ni, Co) cathodes have been explored as novel candidates for thermal batteries in many studies; however, the discharge characteristics (1, 2, 3 plateau) of single cells in thermal batteries with different cathodes have not been elucidated in detail. In this study, we independently analyzed the discharge voltage and calculated the total polarizations of single cells using MS₂ cathodes. Based on the results of this study, we propose NiS₂ as a potential cathode material for use in thermal batteries.

We investigated the sintering behavior and piezoelectric properties of lead-free (K0.5Na0.5)NbO3 ceramics co-doped with excess 0.01 mol ZnO and x mol MnO2, where x was varied from 0 to 0.03. Excess MnO2 addition was found to retard the grain growth and densification during sintering. However, 0.005 mol MnO2 addition improved the piezoelectric properties of 0.01 mol ZnO added (K0.5Na0.5)NbO3 ceramics. The planar mode piezoelectric coupling coefficient, electromechanical quality factor, and piezoelectric constant d33 of 0.01 mol ZnO and 0.005 mol MnO2 added specimen were 0.40, 304, and 214 pC/N, respectively.

We investigated the effect of Ta doping on the dielectric and piezoelectric properties oflead-free (K0.5Na0.5)NbO3 ceramics prepared using a conventional ceramic processing. X-ray diffractionanalysis revealed that Ta was perfectly substituted into Nb-sites in the range of 0 to 20 at%. As Tacontent in the KNN increased, the sinterability of KNN ceramics was significantly degraded while the Tadoping enhanced the piezoelectric constant d33, planar mode piezoelectric coupling coefficient (kp), andelectromechanical quality factor (Qm). The highest values for d33, kp, and Qm was found to be 156 pC/N,0.37, and 155, respectively.

Recently, amorphous oxide semiconductors (AOSs) based thin-film transistors (TFTs) have received considerable attention for application in the next generation displays industry. The research trends of AOSs based TFTs investigation have focused on the high device performance. The electrical properties of the TFTs are influenced by trap density. In particular, the threshold voltage (Vth) and subthreshold swing (SS) essentially depend on the semiconductor/gate-insulator interface trap. In this article, we investigated the effects of Ar plasma-treated SiO2 insulator on the interfacial property and the device performances of amorphous indium gallium zinc oxide (a-IGZO) TFTs. We report on the improvement in interfacial characteristics between a-IGZO channel layer and gate insulator depending on Ar power in plasma process, since the change of treatment power could result in different plasma damage on the interface.