전기 캐비닛은 병원 및 발전소와 같은 중요 시설물에서 운영과 관리를 위한 시스템 기기를 보관한 다. 지진과 같은 극한하중 하에서 중요 시설물은 지속적으로 운영 및 제어되어야 하기 때문에 전기 캐 비닛의 안전성은 평가되고 확보되어야 한다. 하지만 실험적 연구만으로 다양한 유형의 전기 캐비닛에 대한 내진성능 평가를 수행하는 것은 많은 제약이 있다. 따라서 다양한 연구자들은 전기 캐비닛의 유 한요소 모델을 구축하고 내진성능 평가를 수행하였다. 유한요소 모델은 beam-stick 요소를 기반으로 구축되거나 3차원 shell 요소를 기반으로 구축되어왔다. Beamk-stick 요소 기반 및 3차원 shell 요소 기반의 유한요소 모델에 대한 전체거동에 대한 비교를 수행한 사례는 있으나 국부거동에 대한 동적응 답을 비교한 연구사례는 없다. 전기 캐비닛은 내부에 시스템 기기가 보관되므로 내부의 국부거동 기반 의 내부응답을 포착할 수 있어야한다. 따라서 본 연구는 단문형 전기 캐비닛에 대한 beam-stick 요소 및 3차원 shell요소를 기반으로 유한요소 모델을 구축하고 동일한 높이에서 가속도 응답을 비교하였다. 결과적으로 beam-stick 요소 기반의 3차원 유한요소 모델은 전기 캐비닛 내부 응답 스펙트럼을 정확 히 예측할 수 없기 때문에 내부 응답 스펙트럼을 위해서는 3차원 shell요소 기반의 상세 유한요소 모 델을 사용해야 한다.

Silicon carbide (SiC) has emerged as a promising material for next-generation power semiconductor materials, due to its high thermal conductivity and high critical electric field (~3 MV/cm) with a wide bandgap of 3.3 eV. This permits SiC devices to operate at lower on-resistance and higher breakdown voltage. However, to improve device performance, advanced research is still needed to reduce point defects in the SiC epitaxial layer. This work investigated the electrical characteristics and defect properties using DLTS analysis. Four deep level defects generated by the implantation process and during epitaxial layer growth were detected. Trap parameters such as energy level, capture-cross section, trap density were obtained from an Arrhenius plot. To investigate the impact of defects on the device, a 2D TCAD simulation was conducted using the same device structure, and the extracted defect parameters were added to confirm electrical characteristics. The degradation of device performance such as an increase in on-resistance by adding trap parameters was confirmed.

In this investigation, samples of the chemical (Hg1-xPbxBa2Ca1.8Mg0.2Cu3O8+δ) were prepared utilizing a solid-state reaction technique with a range of lead concentrations (x = 0.0, 0.05, 0.10, and 0.20). Specimens were pressed at 8 tons per square centimeter and then prepared at 1,138 K in the furnace. The crystalline structure and surface topography of all samples were examined using X-ray diffraction (XRD) and atomic force microscopy (AFM). X-ray diffraction results showed that all of the prepared samples had a tetragonal crystal structure. Also, the results showed that when lead was partially replaced with mercury, an increase in the lead value impacted the phase ratio, and lattice parameter values. The AFM results likewise showed excellent crystalline consistency and remarkable homogeneity during processing. The electrical resistivity was calculated as a function of temperature, and the results showed that all samples had a contagious behavior, as the resistivity decreased with decreasing temperature. The critical temperature was calculated and found to change, from 102, 96, 107, and 119 K, when increasing the lead values in the samples from 0.0 to 0.05, 0.10, and 0.20, respectively.

Fluorine-doped tin oxide (FTO) has been used as a representative transparent conductive oxide (TCO) in various optoelectronic applications, including light emitting diodes, solar cells, photo-detectors, and electrochromic devices. The FTO plays an important role in providing electron transfer between active layers and external circuits while maintaining high transmittance in the devices. Herein, we report the effects of substrate rotation speed on the electrical and optical properties of FTO films during ultrasonic spray pyrolysis deposition (USPD). The substrate rotation speeds were adjusted to 2, 6, 10, and 14 rpm. As the substrate rotation speed increased from 2 to 14 rpm, the FTO films exhibited different film morphologies, including crystallite size, surface roughness, crystal texture, and film thickness. This FTO film engineering can be attributed to the variable nucleation and growth behaviors of FTO crystallites according to substrate rotation speeds during USPD. Among the FTO films with different substrate rotation speeds, the FTO film fabricated at 6 rpm showed the best optimized TCO characteristics when considering both electrical (sheet resistance of 13.73 Ω/□) and optical (average transmittance of 86.76 % at 400~700 nm) properties with a figure of merit (0.018 Ω-1).

ZnO/Cu/ZnO (ZCZ) thin films were deposited at room temperature on a glass substrate using direct current (DC) and radio frequency (RF, 13.56 MHz) magnetron sputtering and then the effect of post-deposition electron irradiation on the structural, optical, electrical and transparent heater properties of the films were considered. ZCZ films that were electron beam irradiated at 500 eV showed an increase in the grain sizes of their ZnO(102) and (201) planes to 15.17 nm and 11.51 nm, respectively, from grain sizes of 13.50 nm and 10.60 nm observed in the as deposited films. In addition, the film’s optical and electrical properties also depended on the electron irradiation energies. The highest opto-electrical performance was observed in films electron irradiated at 500 eV. In a heat radiation test, when a bias voltage of 18 V was applied to the film that had been electron irradiated at 500 eV, its steady state temperature was about 90.5 °C. In a repetition test, it reached the steady state temperature within 60 s at all bias voltages.

The concept of deep geological disposal for high-level radioactive waste is based on an engineered barrier system (EBS), including a canister, bentonite buffer and backfill material. The bentonite buffer is key component of the EBS to prevent groundwater infiltration and radionuclide leakage. However, the bentonite buffer can become saturated due to groundwater flow through the excavation damaged zone in the adjacent rock, causing erosion of bentonite buffer and affecting the long-term performance of EBS. While the RH (relative humidity) sensor is commonly used to assess the degree of saturation in the bentonite buffer, it has a critical challenge due to its sensor size, which can disturb the overall integrity of the bentonite buffer during the initial installation process. In contrasts, the electrical resistivity test, widely known as a non-destructive method, is used to predict soil properties such as the degree of saturation and water contents. This method measures the electric resistance of materials using electric current induced by electric potential difference between two electrodes. Notably, there is no study that assess the integrity of bentonite buffer in a nuclear waste repository using electrical resistivity measurement. This study presents the electrical resistance numerical module under steady state using commercial finite element method (FEM), and quantitatively estimate the change of electrical resistance according to saturation and erosion of bentonite buffer. Furthermore, the electric potential and current density distribution formed between two electrodes are analyzed.

Tomatoes in greenhouse are a widely cultivated horticultural crop worldwide, accounting for high production and production value. When greenhouse ventilation is minimized during low temperature periods, CO2 enrichment is often used to increase tomato photosynthetic rate and yield. Plant-induced electrical signal (PIES) can be used as a technology to monitor changes in the biological response of crops due to environmental changes by using the principle of measuring the resistance value, or impedance, within the crop. This study was conducted to investigate the relationship between tomato growth data, vital response, and PIES resulting from CO2 enrichment in greenhouse tomatoes. The growth of tomato treated with CO2 enrichment in the morning was significantly better in all items except stem diameter compared to the control, and PIES values were also higher. The growth of tomato continuously applied with CO2 was better in the treatment groups than control, and there was no significant difference in chlorophyll fluorescence and photosynthesis. However, PIES and SPAD values were higher in the CO2 treatment group than control. CO2 enrichment have a direct relationship with PIES, growth increased, and transpiration increased due to the increased leaf area, resulting in increased water absorption, which appears to be reflected in PIES, which measures vascular impedance. Through this, this study suggests that PIES can be used to monitor crops due to environmental changes, and that PIES is a useful method for non-destructively and continuously monitoring changes of crops.

This study focuses on how the partial substitution of copper by nickel nanoparticles affects the electrical and structural properties of the Bi2Ba2Ca2Cu2.9Ni0.1O10+δ, Bi2Ba2Ca2Cu2.8Ni0.2O10+δ and Bi2Ba2Ca2Cu2.6Ni0.4O10+δ compounds. Approximate values of crystallization size and crystallization percentage for the three compounds were calculated using the Scherer, modified Scherer, and Williamson-Hall methods. A great similarity was observed in the crystal size values from the Scherer method, 243.442 nm, and the Williamson-Hall method, 243.794 nm for the second sample. At the same time this sample exhibited the highest crystal size value for the three methods. In the examination of electrical properties, the sample with 0.1 partial substitution, Bi2Ba2Ca2Cu2.9Ni0.1O10+δ was determined to be the best with a critical temperature of 100 K and an energy gap of 6.57639 × 10-21 MeV. Using the SEM technique to analyze the structural morphology of the three phases, it was discovered that the size of the granular forms exceeds 25 nm. It was determined that the samples’ shapes alter when nickel concentration rises. The patterns that reveal the distribution of the crystal structure also exhibit clear homogeneity.

Transparent conductive tungsten (W) doped indium oxide (In2O3; IWO) films were deposited at different substrate bias voltage (-Vb) conditions at room temperature on glass substrates by radio frequency (RF) magnetron sputtering and the influence of the substrate bias voltage on the optical and electrical properties was investigated. As the substrate bias voltage increased to -350 Vb, the IWO films showed a lower resistivity of 2.06 × 10-4 Ωcm. The lowest resistivity observed for the film deposited at -350 Vb could be attributed to its higher mobility, of 31.8 cm2/Vs compared with that (6.2 cm2/Vs) of the films deposited without a substrate bias voltage (0 Vb). The highest visible transmittance of 84.1 % was also observed for the films deposited at the -350 Vb condition. The X-ray diffraction observation indicated the IWO films deposited without substrate bias voltage were amorphous phase without any diffraction peaks, while the films deposited with bias voltage were polycrystalline with a low In2O3 (222) diffraction peak and relatively high intensity (431) and (046) diffraction peaks. From the observed visible transmittance and electrical properties, it is concluded that the opto-electrical performance of the polycrystalline IWO film deposited by RF magnetron sputtering can be enhanced with effective substrate bias voltage conditions.

The thermoelectric effect, which converts waste heat into electricity, holds promise as a renewable energy technology. Recently, bismuth telluride (Bi2Te3)-based alloys are being recognized as important materials for practical applications in the temperature range from room temperature to 500 K. However, conventional sintering processes impose limitations on shape-changeable and tailorable Bi2Te3 materials. To overcome these issues, three-dimensional (3D) printing (additive manufacturing) is being adopted. Although some research results have been reported, relatively few studies on 3D printed thermoelectric materials are being carried out. In this study, we utilize extrusion 3D printing to manufacture n-type Bi1.7Sb0.3Te3 (N-BST). The ink is produced without using organic binders, which could negatively influence its thermoelectric properties. Furthermore, we introduce graphene oxide (GO) at the crystal interface to enhance the electrical properties. The formed N-BST composites exhibit significantly improved electrical conductivity and a higher Seebeck coefficient as the GO content increases. Therefore, we propose that the combination of the extrusion 3D printing process (Direct Ink Writing, DIW) and the incorporation of GO into N-BST offers a convenient and effective approach for achieving higher thermoelectric efficiency.

An all-perovskite oxide heterostructure composed of SrSnO3/Nb-doped SrTiO3 was fabricated using the pulsed laser deposition method. In-plane and out-of-plane structural characterization of the fabricated films were analyzed by x-ray diffraction with θ-2θ scans and φ scans. X-ray photoelectron spectroscopy measurement was performed to check the film’s composition. The electrical transport characteristic of the heterostructure was determined by applying a pulsed dc bias across the interface. Unusual transport properties of the interface between the SrSnO3 and Nb-doped SrTiO3 were investigated at temperatures from 100 to 300 K. A diodelike rectifying behavior was observed in the temperature-dependent current-voltage (IV) measurements. The forward current showed the typical IV characteristics of p-n junctions or Schottky diodes, and were perfectly fitted using the thermionic emission model. Two regions with different transport mechanism were detected, and the boundary curve was expressed by ln I = -1.28V - 13. Under reverse bias, however, the temperature- dependent IV curves revealed an unusual increase in the reverse-bias current with decreasing temperature, indicating tunneling effects at the interface. The Poole-Frenkel emission was used to explain this electrical transport mechanism under the reverse voltages.

The Ag/WC electrical contacts were prepared via powder metallurgy using 60 wt% Ag, 40 wt% WC, and small amounts of Co3O4 with varying WC particle sizes. After the fabrication of the contact materials, microstructure observations confirmed that WC-1 had an average grain size (AGS) of 0.27 μm, and WC-2 had an AGS of 0.35 μm. The Ag matrix in WC-1 formed fine grains, whereas a significantly larger and continuous growth of the Ag matrix was observed in WC-2. This indicates the different flow behaviors of liquid Ag during the sintering process owing to the different WC sizes. The electrical conductivities of WC-1 and WC-2 were 47.8% and 60.4%, respectively, and had a significant influence on the Ag matrix. In particular, WC-2 exhibited extremely high electrical conductivity owing to its large and continuous Ag-grain matrix. The yield strengths of WC-1 and WC-2 after compression tests were 349.9 MPa and 280.7 MPa, respectively. The high yield strength of WC-1 can be attributed to the Hall–Petch effect, whereas the low yield strength of WC-2 can be explained by the high fraction of high-angle boundaries (HAB) between the WC grains. Furthermore, the relationships between the microstructure, electrical/mechanical properties, and deformation mechanisms were evaluated.

국내외 매년 지속적으로 증가하는 대기오염의 상당량이 선박에서 배출되고 있으며, 이러한 선박에서의 배출량을 감축하기 위 해 정부는 환경규제를 강화하고 해양대기환경 개선을 위해 「환경친화적 선박의 개발 및 보급 촉진에 관한 법률」을 제정 및 시행하여 친환경 에너지를 동력원으로 사용하는 환경친화적 선박을 보급하여 해양오염 저감 기술이 개발되도록 하고 있다. 환경친화적 선박의 기 술은 최근 순수 전기추진 내지는 전기복합 추진체계까지 진화하고 있으나, 선박의 안전한 운용을 위한 검사 및 설비기준 등 관련제도의 정비는 이를 못 따라가는 실정으로, 특히 국내 연안선박의 다수를 차지하는 어선에 대한 제도는 정비가 시급한 시점이다. 이번 연구를 통 해 어선에의 전기복합 추진체계 등의 적용을 위해 핵심기자재인 배터리, 전력변환장치 등을 정의하고 이에 필요한 안전기준을 진단, 마련 하여 친환경 어선의 도입과 보급을 위해 관련된 산업을 지원할 수 있도록 최소한의 안전기준안을 마련하고자 한다.

AZO/Cu/AZO thin films were deposited on glass by RF magnetron sputtering. The specimens showed the preferred orientation of (0002) AZO and (111) Cu. The Cu crystal sizes increased from about 3.7 nm to about 8.5 nm with increasing Cu thickness, and from about 6.3 nm to about 9.5 nm with increasing heat treatment temperatures. The sizes of AZO crystals were almost independent of the Cu thickness, and increased slightly with heat treatment temperature. The residual stress of AZO after heat treatment also increased compressively from -4.6 GPa to -5.6 GPa with increasing heat treatment temperature. The increase in crystal size resulted from grain growth, and the increase in stress resulted from the decrease in defects that accompanied grain growth, and the thermal stress during cooling from heat treatment temperature to room temperature. From the PL spectra, the decrease in defects during heat treatment resulted in the increased intensity. The electrical resistivities of the 4 nm Cu film were 5.9 × 10-4 Ω ‧ cm and about 1.0 × 10-4 Ω ‧ cm for thicker Cu films. The resistivity decreased as the temperature of heat treatment increased. As the Cu thickness increased, an increase in carrier concentration resulted, as the fraction of AZO/Cu/AZO metal film increased. And the increase in carrier concentration with increasing heat treatment temperature might result from the diffusion of Cu ions into AZO. Transmittance decreased with increasing Cu thicknesses, and reached a maximum near the 500 nm wavelength after being heat treated at 200 °C.

나노복합재료는 다기능성과 고성능을 가지는 혁신적인 복합재료이다. 나노 스케일 필러의 혼입함으로써 복합재료의 전기적, 역학 적 및 열적 특성이 크게 향상될 수 있기 때문에 나노 스케일 필러를 이용한 나노복합재료의 특성화에 관한 다양한 연구가 광범위하게 수행되어 왔다. 특히, 탄소계 나노 필러(탄소나노튜브, 카본블랙, 그래핀 나노판 등)를 활용하여 전기/역학적 특성을 향상시킨 나노복 합소재 개발에 관한 연구들이 복합재료 분야에서 큰 관심을 받고있다. 본 논문은 실제 응용에 필수적인 나노복합재료의 전기/역학적 특성을 문헌조사를 통해 고찰하는 것을 목표로 한다. 또한, 나노복합재료의 전기/역학적 특성 예측을 위한 최신 멀티스케일 모델링 연 구들에 대해서 검토하고, 멀티스케일 모델링에 대한 과제와 향후 발전 가능성에 대해서 논의한다.

Background: Core muscle weakness occurs due to trunk asymmetry and spinal malalignment after stroke. Core exercise is being implemented to improve trunk control and sitting position in stroke patients. Objectives: To investigated the effects of core muscle electrical stimulation on trunk control and dynamic balance in stroke patients. Design: Quasi-experimental study. Methods: A total of 30 stroke patients were recruited and divided into two groups: experimental group (core muscle electrical stimulation group) and control group (sham core muscle electrical stimulation group). Trunk impairment scale (TIS) was used to measure trunk control. BioRescue was used to measure sitting dynamic balance. Results: In both groups, all TIS scores and sitting dynamic balance abilities were improved increased significantly after intervention (P<.05). Changes in TIS scores and sitting dynamic balance abilities were significantly greater in the experimental group than the control group (P<.05). Conclusion: It was found that core muscle electrical stimulation can be used as an effective method for trunk control and balance recovery in stroke patients.

Laser-induced graphene (LIG) uses a CO2 infrared laser scriber for transforming specific polymer substrates into porous graphene. This technique is simple, scalable, low-cost, free of chemicals, and produces a 3D graphene for applications across many fields. However, the resulting 3D graphene is highly sensitive to the lasing parameters used in their production. Here, we report the effects of power, raster speed, number of lasing passes (with and without spot overlapping) on the resulting LIG structure, morphology, and sheet resistance, using a polyimide (PI) substrate. We find that the number of lasing passes, laser spot overlapping and brand of PI used had a strong influence on the quality of the LIG, measured in terms of the IG/ ID and I2D Raman bands and sheet resistance. Increasing number of passes and overlapping of laser spots led to increased LIG pore sizes, larger graphene scales, and reduced sheet resistance. Furthermore, the over-the-counter desktop CO2 laser engraving unit used introduced additional restrictions that limited the quality of the LIG produced, particularly due to inconsistent control of the laser scribing speed and a poor thermal management of the laser unit.

Metals had been significantly substituted by synthetic polymers in most of our daily requirements, thus relaxing our life. Out of many applied areas, synthetic polymers especially conducting polymers had shown their marked effect and potential. Batteries, pseudocapacitors, superconductors, etc. are the potential zones where conducting polymers are chiefly employed owing to their appreciable conductivity, cost efficiency, and corrosion inhibition nature. Apart from energy storage devices, these conducting polymers find their potential application in biosensors, lasers, corrosion inhibitors, electrostatic materials, conducting adhesives, electromagnetic interference shielding, and others. These all applications including energy storage are due to astonishing properties like high conductivity, flexibility, tuneability, easy processibility, chemical, thermal and mechanical stability, easy and enhanced charge transportation, lightweight, etc. Conducting polymers are extensively studied for their application in energy storage batteries, for which the material under investigation needs to be electrically conductive. However, the conducting nature of these specific conducting polymers is dependent on numerous factors. This review discussed the effect of certain potential factors such as polymerization techniques temperature, doping, bandgap, extended conjugation, solvent, etc. on the electrical/electrochemical conductivity of these conducting polymers. These all factors with their specific variations are found to have a noticeable consequence on the electrical conductivity of the investigated conducting polymer and hence on the energy storage carried by them. This review could be proved beneficial to the readers, who can judiciously implement the conclusions to their research related to conducting polymers and their composites for generating highly efficient energy storage systems.