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        검색결과 390

        1.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Leydig cells, crucial for testosterone production, express ion channels like ANO1 that influence hormone secretion. This study investigates the expression and role of the Tandem of P domains in a weak inward rectifying K+ channel-related Acid-Sensitive K+-1 (TASK-1) channel in these cells, exploring its impact on testicular function and steroidogenesis. Methods: TASK-1 expression in Leydig cells was confirmed using immunostaining, while RT-PCR and Western Blot (WB) validated its expression in the TM3 Leydig cell line. The effect of a TASK-1 channel blocker on cell viability was assessed through live/dead staining and MTT assays. Additionally, the blocker’s effect on testosterone secretion was evaluated by measuring testosterone levels. Results: Immunohistochemical analysis revealed a predominant presence of TASK- 1, along with c-Kit and ANO-1, in Leydig cells adjacent to seminiferous tubules and also in Sertoli and spermatogenic cells. Expression levels of TASK-1 mRNA and protein were significantly higher in TM3 Leydig cells compared to TM4 Sertoli cells. In addition, blocking TASK-1 in TM3 cells with ML365 induced cell death but did not affect LHinduced testosterone secretion. Conclusions: These findings suggest that TASK-1 in Leydig cells is crucial for their viability and proliferation, highlighting its potential importance in testicular physiology.
        4,000원
        3.
        2023.11 구독 인증기관·개인회원 무료
        If radioactive plumes are released outside due to loss of containment building integrity during a nuclear power plant accident, these materials might travel with the wind, affecting both the surrounding environment and neighboring countries. In China, most nuclear power plants are located on the eastern coast. Consequently, a radioactive plume generated during an accident could negatively impact even the western part of the Korean Peninsula due to westerly winds. To detect such problems early, respond quickly, and protect residents, a system that can monitor aerial radiation under normal conditions is needed. Additionally, a detection system that can operate in real-time in an emergencies conditions is required. The current method for aerial radiation measurement takes environmental radiation data from a monitoring post 1.5 m above the ground and converts it to altitude. To measure actual aerial radiation, an expansive area is surveyed by aircraft. However, this approach is both time-consuming and expensive. Thus, to monitor radioactive plumes influenced by environmental factors like wind, we need a radiation detector that can gauge both radioactivity and directionality. In this study, we developed a radiation detector capable of assessing both the radioactivity and directionality of a radioactive plume and conducted its performance evaluation. We miniaturized the radiation detector using a CZT (Cadmium Zinc Telluride) sensor, enabling its mounting on unmanned aerial vehicles like drones. It is configured with multi-channels to measure directionality of a radioactive plumes. For performance evaluation, we positioned two-channel CZT sensors at 90 degrees and measured the energy spectrum for angle and distance using a disk-type radioactive isotope. Using this method, we compared and analyzed the directionality performance of the multi-channel radiation detector. We also confirmed its capability to discern specific radioactivity information and nuclide types in actual radioactive plumes. Our future research direction involves mounting the multi-channel radiation detector on a drone. We aim to gather actual aerial radiation data from sensors positioned in various directions.
        4.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Despite the presence of the p-Channel MOSFET inrush current limiter circuit within the power supply unit of military radar, The internal MOSFET and DC-DC Converter has been damaged due to the high inrush current. In this paper, the cause of the high inrush current was identified by analyzing the p-Channel MOSFET inrush current limiter circuit. Based on the analysis, the high inrush current was reduced by about 60% by adjusting the time constant of the source-to-gate elements compared to before improvement.
        4,000원
        5.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The objectives of this study are to evaluate the condition of concrete bridge decks using the multi-channel ground penetrating radar (GPR) testing and compare the value of its dielectric constant value with actual concrete condition. METHODS : The reflection coefficient method was used to measure the dielectric properties of concrete bridge decks. Air-coupled step-frequency GPR testing was used to measure the time taken for reflection from the interfaces between the layers. Specimens of the asphalt mixture and concrete bridge-deck were collected by field coring. GPR testing was conducted on two bridges with different concrete bridge deck conditions on national highways. After the GPR tests, the actual conditions of the concrete bridge deck were investigated using specimen coring. RESULTS : GPR testing indicated that the dielectric constants of concrete bridge decks in good condition ranged from 8 to 10, whereas those corresponding to poor condition ranged from 4 to 6. The results of GPR testing can determine the actual condition and degree of distress of concrete bridge decks determined from the specimen coring data. Therefore, GPR testing is appropriate for nondestructively evaluating the condition of a concrete bridge deck. CONCLUSIONS : The analysis results of the dielectric constants of the concrete bridge deck obtained from multichannel GPR testing were consistent with the actual bridge deck conditions. In the near future, an additional verification process for this approach under different bridge conditions will be required to improve its precision and ensure reliability.
        4,000원
        6.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        아날로그TV 방송 시대에는 Mono/Stereo 오디오 방송과 음 성다중방송이 있었고, 디지털HDTV 방송 시대에는 Dolby AC-3 기술에 의한 5.1채널 입체오디오 방송이 추가 서비스로 이루어졌다. 지금의 4K-UHDTV 방송 시대에는 채널기반 오디 오(Channel-Based Audio) 7.1.4채널 입체오디오 방송을 비롯하 여 객체기반 오디오(Object-Based Audio) 기본방송 및 편파방 송과 해설방송 등 유저의 선택과 맞춤형 방송이 가능하고, 장 면기반 오디오(Scene-Based Audio) 몰입형 공간수음효과 3D 입체음향 방송 등이 MPEG-H 기술에 의해 활용될 수 있다. 본 논문은 국내 UHDTV 방송 전송방식(ATSC 3.0)과 함께 Audio 규격으로 규정된 MPEG-H 기술 응용에 대한 실험을 통 해 오디오 서비스 개발의 가능성을 연구하는데 그 목적을 두고 있다. 이러한 연구를 위해 ‘2022 카타르월드컵’ 기간 중 카타르와 SBS 간 전송링크 구간의 국제신호(IS) 현장음 및 SBS 아나운 서와 해설자 음성 전송용 음향채널 오디오를 소스로 사용하였 으며, 객체기반의 기본, 해설, 현장, 집중 4가지 오디오 모드를 구성하여 SBSi 채널을 통해 모바일 스트리밍 전송을 하였다. 그리고 수신은 SBS 모바일 앱에 Decoder를 설치하여 유저의 음향모드 선택과 활용 및 향후 MPEG-H 기술에 의한 다양한 형태의 오디오 서비스 개발의 가능성을 실험하였다.
        6,400원
        7.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The United States is Korea’s important trading partner, ranking third (13.7%) in exports of fishery products in Korea. The impact on exports to the United States is expected to be significant if the seafood import provisions under the MMPA are implemented in 2024 accordingly. It is expected that documents proving production information will be required for all items when exporting to the U.S. Therefore, this study attempted to examine the current status of exports and exporters in order to understand the actual conditions of major fishery products exported to the United States. Besides, there are currently no official system and procedures in Korea to prove production information for all fishery items, so we tried to suggest implications by examining distribution channels for major export items to the U.S. In this study, five items including seaweed and halibut as domestic aquaculture items, tuna and squid as deep-sea fishing items, and fish cake using imported raw materials were selected as the target items for distribution channel investigation. In addition, this study is meaningful in that it investigated the routes from production to processing, distribution, and export of each item and identified detailed distribution channel for major items exported to the U.S.
        4,800원
        8.
        2023.07 구독 인증기관·개인회원 무료
        With the development of internet and communication technologies, diversification of consumer needs, and intensifying competition, omnichannel is spotlighted among retailers as one of the breakthroughs to survive. Particularly, among scholars and practitioners, cross channel integration (CCI) has been pointed out as a key concept to achieve success in omnichannel, and several successful cases of retailers and strategies implemented under CCI are reported. Nevertheless, due to the wide scope and complexity of CCI, as well as the substantial cost and long-term perspective required for its investment, CCI involves a high level of uncertainty and complicated decision-making. Thus, most retailers are still struggling in achieving the level of CCI that their consumers desire.
        9.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 복수노조 하에서 건설업에서의 교섭창구단일화 및 소수노조 보호제 도의 운영실태를 분석하여 개선방안을 모색하였다. 나아가 교섭창구단일화제 도가 형식이 아닌 실질적인 의미에서 소수노조의 노동3권을 보장하고 사용자 의 경영권과도 균형을 이루기 위한 제도로 자리매김하도록 교섭창구단일화제 도 전반에서 소수노조 노동3권 강화를 위한 실질적인 개선방안을 도출하였다.
        6,400원
        15.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to reveal and compare the differences in the types and characteristics of purchase channel journeys of MZ generation consumers. In this study a survey was conducted on the purchase channel journey of 20 women in the MZ generation using the ethnographic method of in-depth interviews and observations. As a result, three purchase channel journeys were identified: mobile, multi-channel, and offline. These were variously subdivided according to the characteristics of the MZ generations. Gen Z’s journey was categorized into types: fashion platform app, Youtube, multi-channel supplement, multi-channel non-planned store visit, offline loyalty store, and impulsive offline store. Gen M’s journey was categorized as: an online community bond, portal site, online loyalty store, multi-channel brand involvement, multi-channel efficiency, a multi-channel conversion, offline efficiency and offline task. The difference in mobile journey between generations was found in the time and length of the purchase. Gen M recognized both online and offline search processes to be tiring, while Gen Z enjoyed the search process using the online path. In the offline journey Gen Z began with their own intention to purchase, while Gen M sometimes recognized that purchasing fashion products necessary for work was a cumbersome task.
        5,400원
        18.
        2022.05 구독 인증기관·개인회원 무료
        Dry storage is a predominantly used method as a spent nuclear fuel storage system after spent nuclear fuel is cooled in the spent fuel pool. Spent nuclear fuel is highly radioactive and it generates heat called decay heat originated by fission products and radiation. Therefore, temperature of spent nuclear fuel should be predicted whether its cladding temperature is maintained under 400°C, which is the allowable temperature limit of cladding in a dry storage. ANSYS Fluent and COBRA-SFS are predominantly used computational method to investigate the temperature of spent nuclear fuels in a dry storage. Herein, thermal analysis results with the methods were compared based on a Single Assembly Heat Transfer Test, which is a heat test with an electrically heated model of a single PWR fuel assembly in a dry cask performed at the Pacific Northwest Laboratory. Decay heat was 1kW and backfill gas was air. Fix temperature boundary condition is applied to inner shell according to measured temperature. In case of peak cladding temperature (PCT), Fluent predicted 240–284°C, while COBRA-SFS gave 243–292°C. The discrepancy between the codes is under 2.5%. The location where PCT took place was 3.65 m from the bottom of the assembly in both results. However, temperature difference between the upper and lower region of the assembly based on the Fluent was smaller than the temperature difference based on the COBRA-SFS. It means the heat was well transferred in an axial direction with Fluent compared to COBRA-SFS. In lower plenum region where air was naturally circulated, COBRASFS had disadvantages compared to Fluent because it modeled the lower plenum by single node, so it was hard to simulate convection heat transfer by natural circulation. natural circulation speed of air in a center region of the assembly was 0.07–0.1 m·s−1 in both cases.
        20.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        전세계적으로 컨테이너선은 대형화되고 있으며, 2005년 9,200 TEU에 불과하였던 컨테이너선의 크기가 최근에는 24,000 TEU 급으로 확대되었다. 컨테이너선의 대형화와 함께 우리나라에서도 대형 컨테이너선들의 입·출항이 잦아지고 있어 안전 통항에 대한 검토의 필요성이 강조되고 있다. 이에 본 연구에서는 24,000 TEU 컨테이너선을 대상 선박으로 우리나라의 항만 및 어항 설계 기준에 따라 부산신항 및 부산신항 입항을 위해 통과해야 하는 가덕수로에서의 UKC를 산출하였다. 또한 UKC 기준을 충족하면서 항해 가능한 최대속력을 다양한 squat 식을 활용하여 구하였고, 이 결과를 현재의 속력제한 기준과 비교하였다. 연구결과 부산신항에는 흘수대비 10 % 여유수심을 요구하며 이를 만족하는 squat값은 0.95 m였으며, 가능한 최대속력은 11 kts였다. 가덕수로에서는 흘수대비 15 % 여유 수심을 요구하며 이를 만족하는 squat값은 1.78 m였으며, 가능한 최대속력은 15 kts였다. 부산신항에서는 계산결과인 11 kts보다 제한속력이 12 kts로 높게 설정되어 있어 안전측면에서 재고려가 필요하며, 가덕수로에서는 계산결과인 15 kts보다 제한속력이 12 kts로 낮게 설 정되어 있으므로 원활한 통항을 위하여 필요시 속력제한 규정을 높이는 것을 고려해 볼 수 있다. 본 연구는 제한된 요소만을 고려하여 UKC 및 항해 가능한 속력을 산출한 한계를 가지고 있으나 이 연구를 토대로 추가연구가 진행된다면 정확한 UKC 및 안전속력을 제한할 수 있을 것으로 판단된다.
        4,000원
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