일반적으로 전기 패널은 용접이나 앵커링을 통해 기초에 설치된다. 콘크리트 기초-앵커 시스템에서 고려해야 할 열화 요인에 는 콘크리트 기초의 균열이 포함된다. 콘크리트 균열은 전기 패널의 앵커에 영향을 미치는 열화 현상 중 하나로 간주될 수 있다. 또한 독립반 및 열반된 전기 패널의 동적 특성은 상당히 다를 수 있다. 그러나 많은 연구자들이 하나의 전기 캐비닛 시편으로 진동대실험을 수행하였다. 따라서 열반 구성을 고려하여 동적 특성을 평가할 필요가 있다. 본 연구에서는 0.5 mm 및 1.0 mm 균열 폭을 고려하여 콘크리트 기초-앵커 시스템을 설계하였다. 콘크리트 기초-앵커 시스템을 진동대에 고정하고 1∼3개의 열반으로 구성된 단순화된 캐비 닛 모델을 설치하였다. 열반 수와 콘크리트 균열을 매개변수로 고려하여 진동대에 의한 공진주파수 검색 실험을 수행했으며 각 실험편 의 공진 주파수를 비교하였다.

In recent years, electric shock accidents at industrial sites continue to occur, and various measures are being taken to reduce accidents. Among them, safety education is mentioned as a basic measure for the prevention of industrial accidents and the protection of workers. This study attempted to empirically analyze the effect of electrical safety education on safety consciousness and safety behavior and verify whether it is effective. To this end, a total of 343 people, including workplace managers and workers, were surveyed, and frequency analysis, factor analysis, reliability analysis, correlation analysis, and simple linear & hierarchical regression analysis were conducted using the SPSS 24.0 statistical program. As a result of the analysis, first, it was found that the higher the electrical safety education, the more positive (+) effect was on the safety consciousness. Second, it was found that the higher the electrical safety education, the more significant positive (+) effect was on safety behavior. Third, it was found that the higher the safety consciousness, the more positive (+) effect was on safety behavior. Finally, it was verified that safety consciousness plays a partial mediating role in the influence of electrical safety education on safety behavior.

This study systematically analyzed the causes of recurring electric shock accidents using accident analysis techniques and attempted to suggest implications for accident prevention. 124 electrocution death accidents that occurred from 2017 to 2022 were analyzed and classified into four factors(organizational influence, unsafe supervision, preconditions for unsafe acts, and unsafe acts) using the HFACS technique. As a result, First, in terms of organizational influence, many issues related to organizational processes were found, and the main causes were the lack of a safety management manual for electrical work, the lack of risk assessment, and the lack of safety procedures for electrical work. Second, in terms of unsafe supervision, the main causes were inappropriate operations such as not assigning a work supervisor during work or the lack of actual management and supervision. Third, in terms of preconditions for unsafe acts, the main causes were physical and technical problems such as not performing power outage work or not taking protective measures for live parts. Fourth, in terms of unsafe acts, the main causes were analyzed to be violations of safety procedures such as workers mistaking a power outage or not recognizing a current leakage condition, making a wrong judgment of the situation, and shortening the work time and working without safety measures for work convenience. Additionally, when examining whether the personal characteristics of those who died from electric shock had significant differences in unsafe behaviors, it was confirmed that there were significant differences in violations or decision-making errors depending on the industry and electrical-related major.

최근 정부는 노동정책의 일환으로 노동시간과 임금체계 개편을 추진하고 있다. 그러나 제조업 교대제 사업장에서 근무하는 상당수 생산직들은 여전히 노동시간과 연동된 시급제를 적용받고 있다. 이런 실정 에서 정부는 노동시간과 임금체계를 연계하지 않고 각각의 영역에서 따로 변화를 추진하고 있어 정책의 실효성에 의문이 제기되고 있다. 본 연구는 자동차부품업과 전기전자업 사례를 통해 교대제와 임금산정방식 사이의 관계를 살펴보고, 교대제 개편이 이루어질 경우 임금산정방식이 시급제에서 월급제로 전환 가능성을 모색하였다. 분석 결과, 첫째 월급제 친화적인 교대제가 일부 존재하고, 둘째 노동시간 단축과 동시에 월급제를 시행하면 과거로 되돌아가지 않으려는 비가역성(irreversibility)이 높으며, 셋째 월급제 시행으로 인해 수당이 간소화 되고 기본급과 수당의 통합되는 임금구성의 합리화 효과가 발생하였음을 발견하였다. 한편, 월급 제 시행과 노동자들의 근태 사이의 상관성이 낮아 교대제와 임금산정방식의 변화에 있어서 사용자 반대 를 완화하고 노사간 이해 조정 가능성을 확인하였다. 이런 분석 결과를 바탕으로 교대제 사업장 개편과 임금산정방식인 시급제를 월급제로 전환하기 위한 다양한 정책적 시사점을 도출하고 향후 연구과제를 제안했다.

This study delves into the potential application of whisker carbon nanotube (w-CNT) in terms of electrical heating performance, with a particular emphasis on its significance in high-efficiency electrothermal conversion applications. Meanwhile, a comparative study was conducted on traditional carbon nanotubes (T1 and T3) with different aspect ratios. A uniform and dense carbon nanotube paper (BP) was prepared using a vacuum filtration method, including single-layer (T1, T3 and w-CNT BP), double-layer gradient composite (T1/T3-g, w-CNT/T3-g), and mixed composite (T1/T3-m and w-CNT/T3-m). The thickness of each type of BP is approximately 100 μm. The results demonstrated that electrical conductivity and electrical heating performance of single-layer BPs follow the order of T1 > T3 > w-CNT. While, mixed composite BPs are superior to double-layer gradient composite BPs in electrical conductivity and thermal performance. Notably, w-CNT/T3-m BP exhibits excellent electrothermal performance. Under an applied voltage of 5 V, the surface temperature of w-CNT/T3-m BP reaches 190 ℃. When the voltage is increased to 6 V, the surface temperature rises by 150℃ within 10 s, reaching a steady-state temperature of 318 ℃. This excellent electrothermal performance can be attributed to the introduction of w-CNT, which has a perfect and defect free structure according to Raman analysis. In-depth analysis using X-ray diffraction (XRD) indicated a more complete and higher degree of crystallinity in the w-CNT structure. In summary, this study not only provides experimental and theoretical basis for the application of high-performance electrothermal materials based on carbon nanotubes, but also foreshadows their broad application prospects in the field of macroscopic materials.

국제적으로 선박의 온실가스 배출 감소 요구가 증가함에 따라 어선에서의 탄소배출량 저감 역시 중요한 과제가 되었다. 특 히 2023년 기준 국내의 어선 64,233척 중 60,272척이 총톤수 10톤 미만의 소형어선인 점을 고려할 때, 전기추진설비의 안전한 소형어선 적용을 위한 법제 정비가 필요하다. 본 연구는 노르웨이 해사청의 소형 선박 배터리 시스템 안전 규정을 검토하고 국내의 기준인 「전 기추진 선박기준」과 어떠한 차이점이 있는지를 비교·분석하였으며, 이러한 연구를 통해 열폭주 확산 시험의 강화와 절연 성능이 인증 된 냉각수의 사용, 배터리실 내의 배관과 소화전, 환기설비에 대한 각종 요건과 소화설비의 해수 사용을 금지하는 요건 등 소형어선에 서의 안전한 배터리시스템 사용을 위한 관련 법령의 정비 방안을 제안하였다.

High-frequency soft magnetic Ni, Fe, and Co-based thin films have been developed, typically as nanocrystals and amorphous alloys. These Ni, Fe, and Co-based thin films exhibit remarkably good frequency dependence up to high frequencies of several tens of MHz. These properties arise from the moderate magnetic anisotropy and fairly high electrical resistivity that result from the microstructural characteristics of the nanocrystalline and amorphous states. In this paper, Al-Co/AlN-Co and Al-N/AlN-Co multilayer films were deposited using two-facing-target type sputtering (TFTS). Their microstructures, magnetic and electrical properties were studied with the expectation that inserting Al-Co or Al-N as an interlayer could effectively reduce the coercive force and produce films with relatively high resistivity. A new approach is presented for the fabrication of Al-Co (Al-N)/AlN-Co multilayer films, prepared with the TFTS system. The deposited films were isothermally annealed at different temperatures and investigated for microstructure, magnetic properties and resistivity. The TFTS method used in this experiment is suitable for fabricating Al-Co(Al-N)/AlN-Co multilayer films with different layer thickness ratio (LTR). The annealing conditions, thickness of the multilayer film, and LTR can control the physical properties as well as the microstructure of the manufactured film. Magnetization and resistance increased and coercivity decreased as LTR decreased. The thin film with LTR = 0.175 exhibited high resistivity values of 2,500 μΩ-cm, magnetization of 360 emu/cm3, and coercivity of 5 Oe. Results suggests that thin films with such good resistivity and magnetization would be useful as high-density recording materials.

원자력 발전소에 설치되는 안전관련 기기의 손상은 심각한 사고로 이어질 수 있으므로 반듯이 지진안전성을 확보하여야 한 다. MCC, Switchgear, Inverter, Battery charger 등의 전기캐비닛은 대표적인 안전관련 기기이다. 대부분의 실험적 연구는 실험대 상기기의 크기와 실험장비의 성능한계 등으로 인하여 주요부품을 대상으로 하며, 실제 원자력발전소에 납품하는 전기캐비닛을 이용하 여 3축 동시가진에 의한 진동대 실험을 수행한 연구는 많지 않다. 따라서 실제기기를 대상으로 3축 진동대 실험을 통하여 내진성능과 한계상태를 직접적으로 평가하기 위한 연구가 필요하다. 이러한 한계상태평가의 주요 목적은 다양한 부품으로 구성된 캐비닛 단위 실 제기기의 임계 가속도 및 고장 모드를 조사하는 것이다. 본 논문에서는 3축 진동대 실험으로 한계상태 내진성능실험을 수행하여 원자 력발전소에 납품되는 것과 동일한 4종의 전기캐비닛들의 한계상태를 분석하였다.

The present study investigates the impact of freeze–thaw deterioration on the electrical properties and electric-heating capabilities of cement mortar incorporating with carbon nanotubes (CNT) and carbon fibers (CF). Mortar samples, containing 0.5 wt.% CNT and 0.1 wt.% CF relative to the mass of cement, were prepared and subjected to freeze–thaw tests for up to 300 cycles. The electrical properties and electric-heating capability were evaluated every 30 freeze–thaw cycles, and the physicochemical characteristics of the samples were analyzed using X-ray diffraction and mercury intrusion porosimetry. The results indicate a decline in both electrical conductivity and heat-generation capability as the freeze–thaw cycles progress. Furthermore, changes in the pore structure of the mortar samples during the freeze–thaw cycles contributed to damage in the conductive network formed by CNT and CF, resulting in decreased electrical conductivity and heat-generation capabilities of the mortar samples.

Alluvial beds are intimately associated with electrical properties related to soil types, including clay mineral content, porosity, and water content. The hydraulic property governs water movement and storage in alluvial beds. This study revealed electrical resistivity and hydraulic properties in space and time in relation to the hydrogeological data, groundwater pumping, and rainfall infiltration into the alluvial bed located in Daesan-myeon, Changwon City. An electrical resistivity survey with electrode spacings of 2 and 4m using a dipole-dipole array indicates that electrical resistivity changes in the alluvial bed depend on groundwater pumping and rainfall events. Additionally, rainfall infiltration varies with hydraulic conductivity in the shallow zone of the alluvial bed. The 2 m electrode spacing survey confirms that electrical resistivity values decrease at shallow depths, corresponding with rainfall and increased water content in the soil, indicating rainfall infiltration approximately 1-2 m below the land surface. The 4m electrode spacing survey reveals that hydraulic conductivity (K) values and electrical resistivity (ρ) values display an inverse relationship from the surface to the water table (approximately 9 m) and at deeper levels than the water table. Notably, ρ values are impacted by pumping around the depth of the water table at 9 m. This study suggests that time-lapsed electrical resistivity surveys in space and time could be effective tools for detecting the impact of rainfall and pumping, as well as hydraulic conductivity in shallow alluvial beds.

Background: Stress urinary incontinence (SUI) impacts the social, physical, and psychological well-being and quality of life of the patient. Several techniques exist for its management, including transcutaneous electrical stimulation (TES). Objects: We aimed to demonstrate the effects of TES on ultrasonographic variables and quality of life in women with SUI. Methods: This prospective study recruited 21 women who had been diagnosed with grade 1 or 2 SUI between July 2018 and March 2019. The exclusion criteria were pregnancy and a history of urogenital surgery. All participants were assessed at baseline and 8 weeks after intervention initiation. The bladder neck position (BNP), length of the urethra (LU), funneling index (FI), and rhabdosphincter thickness (RT) were measured. The Incontinence-Quality of Life (I-QOL) was used to assess incontinence-specific quality of life. Statistical significance level was set at p < 0.05. Results: Twenty-one patients with SUI used TES for 8 weeks. BNP and FI significantly decreased after intervention (p < 0.05). LU, anterior and posterior RT (indicators of external sphincter hypertrophy) significantly increased post-intervention (p < 0.05). The total I-QOL score increased from 64.81 to 71.86 after the intervention (p < 0.05). Conclusion: This intervention improved BNP, LU, FI, RT, and subjective indicators such as quality of life in women with SUI. Therefore, TES can be an effective non-surgical treatment method for improving SUI symptoms and quality of life in these patients.

Carbon fibers of polyacrylonitrile (PAN) type were coated with nickel nanoparticles using a chemical reduction method in alkaline hydrazine bath. The carbon fibers were firstly heated at 400 °C and then chemically treated in hydrochloric acid followed by nitric acid to clean, remove any foreign particles and functionalized its graphitic surfaces by introducing some functional groups. The functionalized carbon fibers were coated with nickel to produce 10 wt% Cf/Ni nanocomposites. The uncoated heat treated and the nickel coated carbon fibers were investigated by SEM, EDS, FTIR and XRD to characterize the particle size, morphology, chemical composition and the crystal structure of the investigated materials. The nickel nanoparticles were successfully deposited as homogeneous layer on the surface of the functionalized carbon fibers. Also, the deposited nickel nanoparticles have quazi-spherical shape and 128–225 nm median particle size. The untreated and the heat treated as well as the 10 wt% Cf/Ni nanocomposite particles were further reinforced in ethylene vinyl acetate (EVA) polymer separately by melt blending technique to prepare 0.5 wt% Cf-EVA polymer matrix stretchable conductive composites. The microstructures of the prepared polymer composites were investigated using optical microscope. The carbon fibers as well as the nickel coated one were homogenously distributed in the polymer matrix. The obtained samples were analyzed by TGA. The addition of the nickel coated carbon fibers to the EVA was improved the thermal stability by increasing the thermal decomposition temperature Tmax1 and Tmax2. The electrical and the mechanical properties of the obtained 10 wt% Cf/Ni nanocomposites as well as the 0.5 wt% Cf-EVA stretchable conductive composites were evaluated by measuring its thermal stability by thermogravimetric analysis (TGA), electrical resistivity by four probe method and tensile properties. The electrical resistivity of the fibers was decreased by coating with nickel and the 10 wt% Cf/Ni nanocomposites has lower resistivity than the carbon fibers itself. Also, the electrical resistivity of the neat EVA is decreased from 3.2 × 1010 to 1.4 × 104 Ω cm in case of the reinforced 0.5 wt% Cf/Ni-EVA polymer composite. However, the ultimate elongation and the Young’s modulus of the neat EVA polymer was increased by reinforcing with carbon fibers and its nickel composite.

In this study, four different samples of Se60Ge40-xBix chalcogenides glasses were synthesized by heating the melt for 18 h in vacuum Pyrex ampoules (under a 10-4 Torre vacuum), each with a different concentration (x = 0, 10, 15, and 20) of high purity starting materials. The results of direct current (DC) electrical conductivity measurements against a 1,000/T plot for all chalcogenide samples revealed two linear areas at medium and high temperatures, each with a different slope and with different activation energies (E1 and E2). In other words, these samples contain two electrical conduction mechanisms: a localized conduction at middle temperatures and extended conduction at high temperatures. The results showed the local and extended state parameters changed due to the effective partial substitution of germanium by bismuth. The density of extended states N(Eext) and localized states N(Eloc) as a function of bismuth concentration was used to gauge this effect. While the density of the localized states decreased from 1.6 × 1014 to 4.2 × 1012 (ev-1 cm-3) as the bismuth concentration increased from 0 to 15, the density of the extended states generally increased from 3.552 × 1021 to 5.86 × 1021 (ev-1 cm-3), indicating a reduction in the mullet’s randomness. This makes these alloys more widely useful in electronic applications due to the decrease in the cost of manufacturing.

The development of thermoelectric (TE) materials to replace Bi2Te3 alloys is emerging as a hot issue with the potential for wider practical applications. In particular, layered Zintl-phase materials, which can appropriately control carrier and phonon transport behaviors, are being considered as promising candidates. However, limited data have been reported on the thermoelectric properties of metal-Sb materials that can be transformed into layered materials through the insertion of cations. In this study, we synthesized FeSb and MnSb, which are used as base materials for advanced thermoelectric materials. They were confirmed as single-phase materials by analyzing X-ray diffraction patterns. Based on electrical conductivity, the Seebeck coefficient, and thermal conductivity of both materials characterized as a function of temperature, the zT values of MnSb and FeSb were calculated to be 0.00119 and 0.00026, respectively. These properties provide a fundamental data for developing layered Zintl-phase materials with alkali/alkaline earth metal insertions.

본 연구에서는 경피신경전기자극(TENS)을 이용하여 다양한 자극 강도에 따른 뇌혈관에 미치는 영향을 확인하고 자 한다. 특히 비지각적 감각의 전기자극을 통해 총경동맥(CCA)에서의 혈류 변화 및 혈관의 구조적인 변화를 확인 해 보고자 한다. 본 연구에는 20대의 건강한 성인 24명이 참여하였다. 자극 강도는 감각 역치 미만, 감각 역치, 그리 고 감각 역치 초과 세 가지를 각각 랜덤 순서로 적용하였다. 측정위치는 CCA 분기점의 1cm 하단에서 측정하였고, 혈류속도는 C-mode 도플러, 혈관의 구조는 B-mode 영상을 통해 측정하였다. 측정은 각각의 자극별로 중재 전, 중재 중, 그리고 중재 후에 수행하였고 각 세션마다 혈압의 변화를 측정하였다. 그 결과 최고 수축기 속도(PSV)는 역치 미만의 비지각적 감각자극에서 중재 후 유의하게 감소함이 확인되었다(p = .008). 역치 미만의 자극 후 PSV는 자극 전보다 평균 3.04% 유의하게 감소한 것으로 나타났다(p = .011). 반면 CCA의 혈관 직경의 변화는 모든 강도에서 자극 전후 유의한 변화가 나타나지 않았다. 본 연구에서 적용한 단시간의 비지각적 전기자극이 혈관의 직경이나 혈 압의 유의한 변화를 주지 않으면서 즉각적인 혈류속도 감소에 효과가 있음을 발견했다. 따라서 본 연구는 경동맥 부위에 환자의 불편함과 부작용이 없는 전기자극을 통해 뇌혈류의 조절이 가능하다는 것을 보여주는 중요한 시도로 평가될 수 있다.

In this study, the aromatic carbon content of epoxy resin (EP) increased via carbon tar pitch (CTP) modification, and the CTP occurred self-polymerization reaction. The carboxyl and hydroxyl groups of CTP and the hydroxyl and carboxyl groups of EP occurred chemical cross-linking reaction. CTP and graphitization treatment promoted EP CF carbon crystal growth. The graphitization degree of pure EP CF and 40 wt% CTP modified EP CF are 8.42% and 44.21%, respectively. With the increase CTP content, the cell size, ligament junction and density of graphitization modified EP CF gradually increased, while the number of pores and cells gradually decreased. The cell size, ligament junction size and density of 40 wt% CTP modified graphitization EP CF increased to 1200 μm, 280 μm and 0.5033 g/cm3, respectively. EP CF exhibits entangling carbon ribbon and isotropic amorphous carbon. The 40 wt% CTP modified EP CF is composed of evenly distributed amorphous resin carbon and graphite domain CTP carbon. The graphitization modified EP CF improved electrical conductivity, and the electrical conductivity of 40 wt% CTP modified EP CF is 126.6 S/m. The compressive strength can be decided by EP carbon strength and its char yield, and graphitization 40 wt% CTP modified EP CF reached 4.9 MPa. This study provides some basis for preparation and application of CTP modified EP CF.

In the present study, the effects of electrodes type (copper, steel or CFRP) and design (plate or mesh) on electrical stability of conductive cement as exposed to various weathering conditions were investigated. To fabricate these composites, multiwalled carbon nanotube and carbon fiber were added to the cement composites by 0.6 and 0.4% by cement mass. Seven different types of electrodes were embedded to the samples, and their electrical stability was examined during the curing period. In addition, the fabricated samples were exposed to water ingress and cyclic heating conditions. Then, the compressive strength of the samples was evaluated to observe the interfacial bonding between the cement paste and electrodes. Based on the experimental results, it was found that the samples showed different electrical stability even their mix proportion was same. Thus, it can be concluded that the type and design of the electrodes are important in measuring the electrical properties of the conductive cement composites. Specifically, an improved electrical stability of electrodes is required when they are exposed to various weathering conditions.