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        검색결과 91

        1.
        2023.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        BaTiO3-Poly vinylidene fluoride (PVDF) solution was prepared by adding 0~25 wt% BaTiO3 nanopowder and 10 wt% PVDF powder in solvent. BaTiO3-PVDF film was fabricated by spreading the solution on a glass with a doctor blade. The output performance increased with increasing BaTiO3 concentration. When the BaTiO3 concentration was 20 wt%, the output voltage and current were 4.98 V and 1.03 μA at an applied force of 100 N. However, they decreased when the over 20 wt% BaTiO3 powder was added, due to the aggregation of particles. To enhance the output performance, the generator was poled with an electric field of 150~250 kV/cm at 100 °C for 12 h. The output performance increased with increasing electric field. The output voltage and current were 7.87 V and 2.5 μA when poled with a 200 kV/cm electric field. This result seems likely to be caused by the c-axis alignment of the BaTiO3 after poling treatment. XRD patterns of the poled BaTiO3-PVDF films showed that the intensity of the (002) peak increased under high electric field. However, when the generator was poled with 250 kV/cm, the output performance of the generator degraded due to breakdown of the BaTiO3-PVDF film. When the generator was matched with 800 Ω resistance, the power density of the generator reached 1.74 mW/m2. The generator was able to charge a 10 μF capacitor up to 1.11 V and turn on 10 red LEDs.
        4,000원
        2.
        2023.11 구독 인증기관·개인회원 무료
        Thermal cutting processes that can be applied to dismantling nuclear power plants include oxygen cutting, plasma cutting, and laser cutting. According to the global trend, research projects are being carried out in various countries to upgrade laser cutting, and many studies are also being conducted in Korea with plans to apply laser cutting processes when dismantling nuclear power plants. However, with the current technology level of the laser cutting process, the maximum thickness that can be cut is limited to 250 mm. Therefore, in this study, a laser-oxygen hybrid cutting process was implemented by adding a laser heat source to the oxygen cutting process that can cut carbon steel with a thickness of 250 mm or more (RV, beam, column, beam, etc.) when dismantling the nuclear power plant. This has the advantage of improving the cutting speed and reducing the cutting width Kerf compared to conventional oxygen cutting. In this research, the laser-oxygen hybrid cutting process consisted of laser cutting to which Raycus’ 8 kW Fiber Laser power source was applied and oxygen cutting to which hydrogen was applied with Fuel Gas. The oxygen torch was placed perpendicular to the test piece, and the laser head was irradiated by tilting 35° to 70°. The effects of cutting directions on quality and performance were studied, and cutting paths were selected by comparing cutting results. Thereafter, it was confirmed that there is an optimal laser output power according to the cutting thickness by studying the effect on the cutting surface quality by changing only the laser output power under the same cutting conditions. The results of this study are expected to be helpful in the remote cutting process using laser-oxygen hybrid cutting when dismantling domestic nuclear power plants in the future.
        3.
        2023.11 구독 인증기관·개인회원 무료
        APro, a process-based total system performance assessment (TSPA) tool for a geological disposal system, has a framework for simulating the radionuclide transport affected by thermal, hydraulic, mechanical or geochemical changes occurred in the disposal system. APro aims to be applied for the TSPA to long-term (> 100,000) evolution scenarios in real-world repository having more than 10,000 boreholes. In this large-scale TSPA, it is important not only to develop a high-performance numerical approach, but also to apply an efficient post-processing approach to massive spatiotemporal data. The post-processing refers to validating numerical analysis results, analyzing and evaluating target systems through data processing or visualization. Since APro uses COMSOL interface, the postprocessing function in COMSOL can be used. However, when the data size increases due to largescale numerical analysis, the time for the COMSOL post-processing increases, resulting in a problem that the analysis and evaluation are not performed effectively. In this case, it is possible to extract necessary data using the COMSOL exporting function and importing it into an external postprocessing program for the analysis and evaluation. In this study, the efficiency of external post-processing with extracted data from COMSOL was reviewed. And, we derived a proper data extraction approach (format and structure) that can increase efficiency of external post-processing.
        4.
        2023.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study explored rhetorical devices and their effect on forming coherent and cohesive wholes in the writing of 61 EFL students. When analyzing their writing using the five-paragraph essay format, 57% of students deviated from the format, with some resorting to their L1 rhetorical structures (the indirect group) and others employing rhetorical preferences presumed to be deterministically influenced by their L1 (the hybrid group). Only 43% adhered to the format (the direct group). Neither the indirect nor the hybrid groups were inferior to the direct group regarding the length and quality of the writing; the direct group was not necessarily better received than the other two. The indirect group had a discernible (even if not statistically significant) impact on the length and quality of the writing. The indirect and hybrid groups were found to have slightly stronger control over cohesion indices. The two groups challenged the Englishonly orientation of the five-paragraph essay by negotiating rhetorical structures, thereby doing translingual dispositions.
        5,800원
        5.
        2023.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Thermoelectric (TE) energy harvesting, which converts available thermal resources into electrical energy, is attracting significant attention, as it facilitates wireless and self-powered electronics. Recently, as demand for portable/wearable electronic devices and sensors increases, organic-inorganic TE films with polymeric matrix are being studied to realize flexible thermoelectric energy harvesters (f-TEHs). Here, we developed flexible organic-inorganic TE films with p-type Bi0.5Sb1.5Te3 powder and polymeric matrices such as poly(3,4-eethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and poly (vinylidene fluoride) (PVDF). The fabricated TE films with a PEDOT:PSS matrix and 1 wt% of multi-walled carbon nanotube (MWCNT) exhibited a power factor value of 3.96 μW ‧ m-1 ‧ K-2 which is about 2.8 times higher than that of PVDF-based TE film. We also fabricated f-TEHs using both types of TE films and investigated the TE output performance. The f-TEH made of PEDOT:PSS-based TE films harvested the maximum load voltage of 3.4 mV, with a load current of 17.4 μA, and output power of 15.7 nW at a temperature difference of 25 K, whereas the f-TEH with PVDF-based TE films generated values of 0.6 mV, 3.3 μA, and 0.54 nW. This study will broaden the fields of the research on methods to improve TE efficiency and the development of flexible organic-inorganic TE films and f-TEH.
        4,000원
        6.
        2023.07 구독 인증기관·개인회원 무료
        Previous studies offered inconsistent empirical results for the influence of customer participation on service satisfaction. One possible explanation for this inconsistency is that existing conceptualizations of customer participation do not clearly differentiate the distinct roles of customer participation in service. To address this gap, Dong and Sivakumar (2015) have proposed an updated classification for customer participation based on “output specificity,” which refers to the degree to that the nature of the output is influenced by the person who provides the resource. The output of the customer participation can either be “specific” or “generic”. The “specific output” is defined as the expected service outcome can be idiosyncratic depending on whether the service is provided by the customer or the employee. In contrast, “generic output” refers to expected service outcome is well defined regardless of whether it is delivered by the service provider or the customer. How output specificity of customer participation influences service satisfaction still lacks of empirical examination.
        7.
        2023.07 구독 인증기관·개인회원 무료
        Previous studies offered inconsistent empirical results for the influence of customer participation on service satisfaction. One possible explanation for this inconsistency is that existing conceptualizations of customer participation do not clearly differentiate the distinct roles of customer participation in service. To address this gap, Dong and Sivakumar (2015) have proposed an updated classification for customer participation based on “output specificity,” which refers to the degree to that the nature of the output is influenced by the person who provides the resource. The output of the customer participation can either be “specific” or “generic”. The “specific output” is defined as the expected service outcome can be idiosyncratic depending on whether the service is provided by the customer or the employee. In contrast, “generic output” refers to expected service outcome is well defined regardless of whether it is delivered by the service provider or the customer. How output specificity of customer participation influences service satisfaction still lacks of empirical examination.
        8.
        2023.05 구독 인증기관·개인회원 무료
        It is important that the plasma torch used in the waste treatment field has a high output to increase throughput. In order to increase the output of the plasma torch, there is a method of increasing the current or extending the length of the plasma arc. Among these methods, high power can be easily achieved simply by increasing current, but it is difficult to ensure electrode life. Therefore, it is necessary to check the appropriate current and arc length conditions to achieve high power and stable operation. In this paper, the power performance according to the arc length, current, and operation mode was confirmed in the transfer mode plasma torch. The test conditions are the distance (arc length) between the plasma torch and the external electrode was set to 5-180 mm, and the current was set to be in the range of 90-460 A. As a result of the test, it was confirmed that the reverse polarity operation had a maximum output of 159 kW depending on the arc length and current, and the positive polarity operation had a maximum output of 138 kW. Through this result, it was confirmed that the arc length had an effect on increasing the output, and that the reverse polarity operation had a longer arc than the positive polarity operation.
        9.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently 3d printer industry has two demands. first is color 3d printing. second is mass production using 3d printer that has large bed. According to previous studies, 3D printed objects have different weights depending on filament colors. 3D printed tensile specimens with filaments of various colors were checked to see they had the same weight. If so, we wanted to see it was statistically significant. As a result, we found that the weight of 3D printed objects was statistically significantly different depending on the filament color. The average weight of 3d printed objects is: Black(8.63g), Blue(8.58g), Yellow(8.53g), White(8.48g), Natural(8.46g), Green (8.45g), Red(8.42g).
        4,000원
        10.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study analyzes the effects of the number of angles and bends on resistance in a conductor-embroidered stitch circuit for efficient power transfer through a conductor of wearable energy harvesting to study changes in power lost through connection with actual solar panels. In this study, the angle of the conductive stitch circuit was designed in units of 30°, from 30° to 180°, and the resistance was measured using an analog Discovery 2 device. The measured resistance value was analyzed, and in the section of the angle where the resistance value rapidly changes, it was measured again and analyzed in units of 5°. Following this, from the results of the analysis, the angle at which the tension was applied to the stitch converges was analyzed, and the resistance was measured again by varying the number of bends of the stitch at the given angle. The resistance decreases as the angle of the stitch decreases and the number of bends increases, and the conductor embroidery stitch can reduce the loss of power by 1.61 times relative to general embroidery. These results suggest that the stitching of embroidery has a significant effect on the power transfer in the transmission through the conductors of wearable energy harvesting. These results indicate the need for a follow-up study to develop a conductor circuit design technology that compares and analyzes various types of stitches, such as curved stitches, and the number of conductors, so that wearable energy harvesting can be more efficiently produced and stored.
        4,000원
        11.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study attempts to analyze the economic impact of the service robot industry using Input-Output analysis, which is conducted based on Demand-driven model, the Leontief price model, the Backward and Forward Linkage Effects, and the Exogenous Methods. In a Demand-driven model analysis, we can conclude that the service robot industry contains characteristics of both the manufacturing industry and the service industry, which causes a positive impact on the overall industry by compensating for the weaknesses of the two industries. The Leontief price analysis indicates when wages in the service robot industry increase, prices related to robot manufacturing also increase. Also, when profits in the service robot industry increase, prices related to service provision increase, too. The Backward and Forward Linkage Effects analysis shows that the service robot industry is highly sensitive to the current economic condition and has a great influence on the service industry. The service robot industry can highlight the aspect of service characteristics when the manufacturing industry is in recession and vice versa. In addition, the service robot industry can be regarded as a value-adding and domestic economy promoting industry which utilizes knowledge of information and communication technologies. It is important to foster the service robot industry in South Korea, which is in economic recession to provide an opportunity to stimulate the growth of both service and robot industries.
        4,000원
        12.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Streaming media is an emerging mode of video playback. It compress a series of multimedia data and transmit the data in real time through the Internet. And It has become an important part of people's daily entertainment and leisure. These streaming media platforms(Including OTT platforms) are full of enormous Intellectual Property(IP). Although there are some original IP, most of them are derived from Chinese classical culture and refreshed vigorously. Owing to digitalization, paper publications gradually broken the restrictions of physical forms and evolved to multiple digital forms in the world. In the thriving contemporary cultural industry, the needs for traditional classics are gradually surpassing that for the pure humanistic value, and thus the culture industry value of them are focused on. Xiyouji is the crystallization of the collective wisdom and imagination of the ancient folk, which has been active in people's daily life with various forms of popular cultural products, such as speech and opera, since the ancient time. Therefore, Xixingji is selected in to this paper as the study object, so as to discuss how the original work is effectively untilized in Xixingji to create the magnificent script and storylines and how Christopher Vogler's narratological theory is adopted to analyze the storytelling and character in animation Xixingji, and also to investigate the market reaction of Xixingji in China and South Korea.
        6,400원
        13.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper proposes a solution to the out-of band oscillation signal and in-band low transmitter power output that occurrs during the low-temperature operation test for the new mine detector GPR signal transmission and reception module. Tests were performed by applying the optimal values of capacitors and inductors through circuit analysis simulation under the limited space, as a result, it was confirmed that the gain and return loss were improved at all-band thereby preventing oscillation signal and low transmitter power output.
        4,000원
        14.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper is a study to improve the energy harvesting output of a TENG(Triboelectric nanogenerator) driven by wind power using fine PTFE(Polytetrafluoroethylene) flakes. The structure of the nanogenerator was manufactured in the cylindrical structure, Al(Aluminium) was attached to the inner wall of the cylinder and the PTFE flakes were rotated by the wind inside the cylinder. The number of contact and separation motions was increased as there are multiple PTFE flakes, resulting in improvement of the harvesting output. Through this, it was evaluated to the energy harvesting output characteristics according to the change in the number of PTFE flakes. Up to the optimum, the energy collection efficiency shows the linear correlation with the increase in PTFE flakes and decreases after that. As the PTFE flakes are more than the optimum, the lowering in the harvesting output is induced by obstructing the flow of wind inside the cylinder.
        4,000원
        15.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to compare the effects of input- and output-based planning (reading a sample passage vs. writing a draft) on the oral performance of L2 learners with low-proficiency. In this study, 16 Korean female junior college students of low English proficiency were divided into two different planning groups. The reading group was required to read a sample passage of the given topic, designed to encourage “noticing” and “focus on form” using input enhancement, while the writing group was asked to write a draft of their speech, using only their own L2 knowledge. After such planning activities, both groups recorded their assigned speaking tasks using Kakao Talk. Eight planning activities and oral performances were completed over the period of the semester. In order to compare the effects of input- and output-based planning on the improvement of overall proficiency, pre- and post-tests, in which the students produced the same narratives, were analyzed using Mann-Whitney U and Wilcoxon signed-rank tests. Furthermore, this study explored any difference in speaking performance after each type of planning and what the learners were actually doing during planning time. The results showed that output-based planning had positive effects on speaking performance and its repeated practice led to the improvement of overall proficiency.
        6,100원
        16.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to analyze the structure, status and economic ripple effects of the fisheries processing industry in Korea using interindustry analysis. Five input-output tables published over the past twenty years have been reclassified with a focus on the fisheries processing sector. Through these multi-period tables, we analyzed changes in the inducing effects in production, value added and employment as well as the backward-forward linkage effects. As a result of the analysis, it was found that the industrial scale of the fisheries processing industry is very small compared to other food manufacturing industries. The backward linkage effect of the fisheries processing industry was greater than that of other industries, but the forward linkage effect was rather low. This means that the fisheries processing industry can be greatly affected by industrial depression of the downstream industries such as fishery and aquaculture. Production and employment-inducing effects of the fisheries processing industry have shown a decreasing trend in recent years. This reflects the reality that intermediate inputs are gradually being replaced by imports from domestic production due to the expansion of market opening and the depletion of fishery resource. In the future, it is necessary to prepare a strategy to increase the value-added productivity of the fisheries processing sector and foster it as an export industry.
        5,400원
        17.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        블레이드는 바람 에너지를 전기 에너지로 변환하기 위한 풍력발전기 시스템의 핵심 요소이다. 블레이드의 공기역학적 설계는 적절한 에어포일을 선택하고 블레이드 축을 따라 최적의 단면을 결정하는 것이다. 본 연구의 목표는 블레이드 에어포일의 모델을 개발하고, 개발한 에어포일의 효율을 분석하는 것이다(블레이드 형상은 수정된 SM 시리즈 프로파일을 기반으로 함). 일반적으로 풍력 터빈 블레이드는 Cl/Cd에 민감하다. 본 연구의 초점은 X-Foil 프로그램을 통해 강한 바람과 돌풍에서의 최고 효율(Cl/Cd)을 위한 에어포일의 좌표를 최적화시키는 것이다. 국내 해역의 난류 특성, 돌풍 및 바람 조건에 대한 적절한 에어포일을 개발하기 위해서는 수치 해석을 통해 에어포일의 길이와 이에 따른 두께비(Y/C), 에어포일의 최대 두께비에 대한 상대 위치(Xd), S형 tail edge 및 비율 등을 계산하여 결정한다. X-Foil 프로그램을 통해 모델링된 2D 모델에 대하여 CFD(Computational Fluid Dynamics) 검증을 반복 수행하여 최적화시켰다.
        4,000원
        19.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        One-dimensional (1D) piezoelectric nanostructures are attractive candidates for energy generation because of their excellent piezoelectric properties attributed to their high aspect ratios and large surface areas. Vertically grown BaTiO3 nanotube (NT) arrays on conducting substrates are intensively studied because they can be easily synthesized with excellent uniformity and anisotropic orientation. In this study, we demonstrate the synthesis of 1D BaTiO3 NT arrays on a conductive Ti substrate by electrochemical anodization and sequential hydrothermal reactions. Subsequently, we explore the effect of hydrothermal reaction conditions on the piezoelectric energy conversion efficiency of the BaTiO3 NT arrays. Vertically aligned TiO2 NT arrays, which act as the initial template, are converted into BaTiO3 NT arrays using hydrothermal reaction with various concentrations of the Ba source and reaction times. To validate the electrical output performance of the BaTiO3 NT arrays, we measure the electricity generated from each NT array packaged with a conductive metal foil and epoxy under mechanical pushings. The generated output voltage signals from the BaTiO3 NT arrays increase with increasing concentration of the Ba source and reaction time. These results provide a new strategy for fabricating advanced 1D piezoelectric nanostructures by demonstrating the correlation between hydrothermal reaction conditions and piezoelectric output performance.
        4,000원
        20.
        2020.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper, we studied the applicability of data driven model, AAKR(Auto-Associative Kernel Regression) for generator power loss estimation. Correlation analysis performed on 39 turbine system variables for dataset construction and then 13 variables were selected as highly correlated with generator power output. For a memory vector, 95~100% thermal power section data were used and data at normal power condition for 3 month were extracted for query vector. Analysis result shows that 9 variables show good prediction between measured and estimated data, 2 variables show good correlation but with small bias and 2 variables show increasing difference and low correlation with the passage of time, which assumed to be cause of electric output loss.
        4,000원
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