• Journal of Electrochemical Science and Technology
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• 제12권3호
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• pp.346-357
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• 2021

In recent years, supercapacitors have been developed rapidly as a rechargeable energy storage device. And the performance of supercapacitors is depending on electrode materials, the preparation method and performance of electrode materials have become the primary goal of scientific development. This study synthesizes Co₃O₄@MnO₂@PPy cathode material with porous pattern core-shell structure by hydrothermal method and electrodeposition. The result samples are characterized by X-ray diffraction transmission/scanning electron microscope, and X-ray photoelectron spectroscopy. Electrochemical evaluation reveals that electrochemical performance is significantly enhanced by PPy depositing. The specific capacitance of Co₃O₄@MnO₂@PPy is 977 F g^-1 at 1 A g^-1, the capacitance retention rate of 105%. Furthermore, the electrochemical performance of Co₃O₄@MnO₂@PPy//AC asymmetric supercapacitor assembles with AC as the negative electrode material is significantly better than that of MnO₂//AC and Co₃O₄@MnO₂//AC. The capacity of Co₃O₄@MnO₂@PPy//AC is 102.78 F g^-1. The capacity retention rate is still 120% for 5000 charge-discharge cycles.

• Journal of Electrochemical Science and Technology
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• 제12권2호
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• pp.246-256
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• 2021

Mo,Cu-doped CeO₂ (CMCuO) nanopowders were synthesized by the nitrate-fuel combustion method aiming to improve the electrical and electrochemical properties of its Mo-doped CeO₂ (CMO) parent by the addition of copper. An electrical conductivity of ca. 1.22·10^-2 S cm^-1 was measured in air at 800℃ for CMCuO, which is nearly 10 times higher than that reported for CMO. This increase was associated with the inclusion of copper into the crystal lattice of ceria and the presence of Cu and Cu₂O as secondary phases in the CMCuO structure, which also could explain the increase in the charge transfer activities of the CMCuO based anode for the hydrogen and carbon monoxide electro-oxidation processes compared to the CMO based anode. A maximum power density of ca. 120 mW cm^-2 was measured using a CMCuO based anode in a solid oxide fuel cell (SOFC) with YSZ electrolyte and LSM-YSZ cathode operating at 800℃ with humidified syngas as fuel, which is comparable to the power output reported for other SOFCs with anodes containing copper. An increase in the area specific resistance of the SOFC was observed after ca. 10 hours of operation under cycling open circuit voltage and polarization conditions, which was attributed to the anode delamination caused by the reduction of the Cu₂O secondary phase contained in its microstructure. Therefore, the addition of a more electroactive phase for hydrogen oxidation is suggested to confer long-term stability to the CMCuO based anode.

• Journal of Information Science Theory and Practice
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• 제11권1호
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• pp.14-30
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• 2023

The purpose of this study is to compare research trends in the information and communication technology (ICT) field between North and South Korea and analyze the differences by using data mining. Frequency analysis, clustering, and network analysis were performed using keywords from seven South Korean and two North Korean ICT academic journals published for five years (2015-2019). In the case of South Korea (S. Korea), the frequency of research on image processing and wireless communication was high at 16.7% and 16.3%, respectively. North Korea (N. Korea) had a high frequency of research, in the order of 18.2% for image processing, 16.9% for computer/Internet applications/security, and 16.4% for industrial technology. N. Korea's natural language processing (NLP) sector was 11.9%, far higher than S. Korea's 0.7 percent. Student education is a unique subject that is not clustered in S. Korea. In order to promote exchanges between the two Koreas in the ICT field, the following specific policies are proposed. Joint research will be easily possible in the image processing sector, with the highest research rate in both Koreas. Technical cooperation of medical images is required. If S. Korea's high-quality image source is provided free of charge to N. Korea, research materials can be enriched. In the field of NLP, it calls for proposing exchanges such as holding a Korean language information conference, developing a Korean computer operating system. The field of student education encourages support for remote education contents and management know-how, as well as joint research on student remote evaluation.

• Journal of Electrochemical Science and Technology
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• 제13권4호
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• pp.472-478
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• 2022

Solar energy harvesting is practiced by various nations for the purpose of energy security and environment preservation in order to reduce overdependence on oil. Converting solar energy into electrical energy through Photovoltaic (PV) module can take place either in on-grid or off-grid applications. In recent time Lithium battery is exhibiting its presence in on-grid applications but its role in off-grid application is rarely discussed in the literature. The preliminary capacity and Peukert's study indicated that the battery quality is good and can be subjected for life cycle test. The capacity of the battery was 10.82 Ah at 1 A discharge current and the slope of 1.0117 in the Peukert's study indicated the reaction is very fast and independent on rate of discharge. In this study Lithium Iron Phosphate battery (LFP) after initial characterization was subjected to life cycle test which is specific to solar off-grid application as defined in IEC standard. The battery has delivered just 6 endurance units at room temperature before its capacity reached 75% of rated value. The low life of LFP battery in off-grid application is discussed based on State of Charge (SOC) operating window. The battery was operated both in high and low SOC's in off-grid application and both are detrimental to life of lithium battery. High SOC operation resulted in cell-to-cell variation and low SOC operation resulted in lithium plating on negative electrode. It is suggested that to make it more suitable for off-grid applications the battery by default has to be overdesigned by nearly 40% of its rated capacity.

• 한국표면공학회지
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• 제56권1호
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• pp.104-114
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• 2023

Three dimensional (3D) porous structures consisting of Cu@CoO core-shell-type nano-dendrites were synthesized and tested as the anode materials in lithium secondary batteries. For this purpose, first, the 3D porous films comprising Cu@Co core-shell-type nano-dendrites with various thicknesses were fabricated through the electrochemical co-deposition of Cu and Co. Then the Co shells were selectively anodized to form Co hydroxides, which was finally dehydrated to get Cu@CoO nanodendrites. The resulting electrodes exhibited very high reversible specific capacity almost 1.4~2.4 times the theoretical capacity of commercial graphite, and excellent capacity retention (~90%@50^th cycle) as compared with those of the existing transition metal oxides. From the analysis of the cumulative irreversible capacity and morphology change during charge/discharge cycling, it proved that the excellent capacity retention was attributed to the unique structural feature of our core-shell structure where only the thin CoO shell participates in the lithium storage. In addition, our electrodes showed a superb rate performance (70.5%@10.8 C-rate), most likely due to the open porous structure of 3D films, large surface area thanks to the dendritic structure, and fast electron transport through Cu core network.

• 대한임상검사과학회지
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• 제55권1호
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• pp.65-70
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• 2023

헌혈을 중심으로 하는 혈액 관리보다 혈액의 사용을 적절히 관리하는 것이 중요하다. 수혈용 혈액 현황의 관리, 수혈의 적정성에 대한 평가, 수혈 관련 부작용의 발생 감시 및 대응, 그 밖에 수혈관리에 필요한 업무를 수행하는 수혈관리실의 역할을 통해 개선효과를 살펴보았다. 수혈관리실의 개설·운영을 통해 수혈적정성 평가 업무를 효율적으로 관리할 수 있지만 혈액의 적정성 평가에 시간이 소요되고 수혈관리실 전담인력이 모든 혈액의 적정성을 평가하기에는 어려운 단점도 있다. 앞으로 한국형 환자 혈액관리(patient blood management, PBM)를 도입해 의료기관 내 안전하고 적정한 수혈관리 구현을 위한 수혈관리실과 수혈관리위원회를 정착시키고, 인력을 교육해야 하는 의료기관의 참여가 필수적이다.

• 한국시뮬레이션학회논문지
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• 제19권4호
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• pp.161-167
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• 2010

유-헬스케어(U-Healthcare)에서 이동 환자 상태에 대한 모니터링 기술은 필수적이다. 모니터링 기술에서는 이동 환자의 생체 정보가 동적 위치 정보와 함께 정해진 목적지 서버로 전송되어야 하는데 모니터링할 환자의 수가 증가하며 각 환자의 이동성이 불규칙함에 따라 적절한 부하균형 단계가 중간에 필요해진다. 토르소(Torus) 구조를 기반으로 한 이동 환자 상시 모니터링 시스템에서는 이를 반영하여 먼저 환자 생체 정보를 중간노드로 전송한 후 부하균형 기반의 우선순위 정책에 따라 목적지 서버로 연이어 전송된다. 본 논문에서는 계층적이며 객체지향적인 정형화 명세를 기반으로 하는 시스템 명세 기법을 사용하여 이러한 이동 환자 상시 모니터링 시스템의 전체 구조와 구성 노드들의 결합 관계를 정의한 후 각 요소의 기능을 유사코드로 설계함으로써 본 시스템이 효과적인 환자 정보 수집과 전송, 분배 및 판단에 효율적임을 시스템 명세 기법을 통하여 검증한다.

• 의학교육논단
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• 제25권1호
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• pp.45-54
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• 2023

We investigated the work-life balance of clinical professors in charge of patient care, research, and education at medical schools and the demand for work-life balance support according to position (professor, associate professor, or assistant professor). In total, 163 clinical professors completed the consent form and participated in the study. They filled out an online survey consisting of questions about essential characteristics, a work-life balance test, stress, burnout, work-life satisfaction, and work-life balance support needs. We analyzed the results by analysis of variance and cross-tabulation using IBM SPSS ver. 23.0. Differences were found in work-life balance, stress, burnout, and satisfaction with life and work by position. The requirements for support for work-life balance also varied by professional status. Professors had a higher balance between life and work than associate professors or assistant professors. The specific requirements for work-life balance support were also slightly different for each position. Overall, there was a high demand for work process simplification and efficiency for work support, flexible working hours and sabbatical years for family and leisure, and career management consulting and training support for growth. Assistant professors and associate professors had a lower level of work-life balance than professors, as well as higher levels of stress and burnout. Professors' job satisfaction was also higher than that of the other groups. Based on the results of this study, we hope that a healthy work environment can be established through work-life balance support suitable for clinical professors' positions.

• 해양환경안전학회지
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• 제29권2호
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• pp.223-229
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• 2023

해수이차전지는 해수를 양극으로 사용하는 차세대 이차전지이다, 해양 자원을 사용하여 가격 경쟁력과 높은 친환경성, 그리고 해양 애플리케이션에 적합한 구조를 가진다. 이러한 장점을 기반으로 지속적 연구개발을 통해 자연 해수 노출을 가정한 파우치 타입 및 각형 타입이 개발되어 왔다. 그러나 이차전지는 전기적 특성상 사용 환경에 따라 용량 및 내부 임피던스가 달라진다. 이러한 특성은 전지의 수명 예측에 활용될 뿐만 아니라 활용하고자 하는 상황에 맞는 용량과 출력에 직접적인 영향을 미친다. 따라서 본 논문에서는 해수이차전지의 사용 환경에 따른 용량 측정과 SoC-OCV 측정 방법을 통한 내부 저항을 분석하고자 한다.

• 무역학회지
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• 제41권5호
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• pp.213-233
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• 2016

FTA 원산지 규정은 품목의 특성에 맞게 산업별 특성 및 양 당사국간의 상황을 고려하여 양 당사국간의 협상에 의해 정해지고 협정문을 통해 규정하고 있으며, 수산물의 원산지결정기준은 크게 완전생산기준을 적용하는 협정과 2단위 세번변경기준을 적용하는 협정으로 나눌 수 있다. 수산물은 HS code Chapter 3에 속하며, 일반적으로 양식 또는 어획에 의한 획득을 통해서 생산된다. 본 연구에서는 이러한 관점에서 각 협정을 비교 하였다. 어획된 수산물의 경우 공해어업과 관련한 배경 지식이 없는 상황에서 업무상 판단 오류가 발생 할 수 있다. 원산지 판정을 위한 선박의 인정 요건과 관련하여 국제 협정에 의해 선박은 등록국의 국기를 게양하고 항행 할 수 있으므로, FTA 원산지규정에 적용할 수 있도록 하는 기국주의 등에 대한 연구를 진행하였다.