• 제목/요약/키워드: Discharge.charge-time

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리튬이온커패시터를 활용한 비상유도등 예비전원장치의 동작 특성 및 점검방법 개선에 관한 연구 (A Study on Improvement of Operation Characteristics and Inspection Method of Standby Power Supply such as Emergency Induction Light using Li-ion Capacitor)

  • 정준채
    • 한국재난정보학회 논문집
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    • 제16권2호
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    • pp.392-401
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    • 2020
  • 연구목적: 본 연구는 비상시의 예비전원장치로 사용 가능한 리튬이온커패시터의 동작 특성을 분석하고, 충·방전시의 선형비례특성을 이용하여 전압을 측정하는 것으로도 예비전원장치의 동작 이상 유무를 판단 할 수 있는 실험근거의 제공을 목적으로 한다. 연구방법: 본 연구를 위한 방법으로 먼저 기존 예비전원장치와 리튬이온커패시터에 대한 동작원리 및 특성을 분석하고, 다음으로 실험에 사용한 유도등의 구성도와 시스템 블록도에 따라 리튬이온커패시터의 전압 측정을 통해 배터리의 보유 전력량을 확인하는 전압대역별 방전전력량 측정 값 테스트와 유도등을 이용한 동작 테스트 실험으로 진행한다. 연구결과: 리튬이온커패시터의 선형비례특성을 이용한 충전전압을 확인하는 것만으로도 정확하게 유도등 램프의 유효동작 시간을 추론 할 수 있는 근거를 제시하고 있다. 결론: 재난 상황 시 리튬이온커패시터를 비상유도등의 예비전원장치로 사용함으로써 비상유도등의 완전 방전을 미연에 방지하고, 예비전원장치의 정상 작동 수행의 문제가 발생하지 않게 하며, 간단한 전압측정만으로도 예비전원장치의 이상 유무를 확인 할 수 있게 하여 향후 피난설비 적용에 많은 활용도를 제시하고자 하였다.

입.퇴원 수속창구 중앙화와 분산화에 따른 이용자의 만족도와 재이용 의사 (The Study of Comparison Satisfaction and Re-use Intention between Central and Ward Reception Desk Users)

  • 함태훈;이경우;손태용;유승흠
    • 한국병원경영학회지
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    • 제14권4호
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    • pp.149-162
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    • 2009
  • The purpose of this study is to design strategic hospital service based on each hospital's features. For this study, an assessment was conducted by 398 in-patents of one university hospital located in Seoul. The self-questionnaires, which were investigated from Oct. 15th to 29th in 2008, compared central reception desk with ward reception desk in satisfaction and re-use rate of patients. The major results of this study are as follow. First, according to each reception desk user, they have different satisfaction of it. As for the staff kindness, admission procedure, discharge procedure and manner of staff, those made patients be gratified as well. Second, when it comes to the intention of re-use, there were no significant features between them. Only convenience in admission and discharge procedure, however, was an attractive factor for the recommendation. Third, this study found out the reasons for higher re-use rate of central reception desk users. Regarding service, they were contented with the time for test and treatment. As for the hospital service, they would like to re-use this hospital because of convenient steps of paying interim fee and getting certificates. Forth, this study found out the reasons for higher re-use rate of ward reception desk users. As a point of hospital service view, they responded that respected privacy, hospital facility and general service were good for staying. As for the manner of staff, they mentioned nurses and staff in charge and whole staff members were kind. When it comes to the procedures of patient management, steps of discharge and paying interim fee were convenience. In conclusion, the results of this study suggest that providing a ward reception desk service can boost the satisfaction and re-use rate of in-patients. Furthermore, this strategic management method would be good for not only cutting the moving line but also efficient in-patient care system. These results can be used for the strategic hospital marketing field, as well. Even though this study has a limitation of the targeted populations which were only in a ward reception desk running hospital, it can say that having competitiveness in satisfaction of hospital service is good for promoting and differencing each hospital. Consequently, whole general management system would be adjusted first for differencing each hospital; however, this sort of additional factor should be concerned as well. I expect that this study would give meaningful data for designing strategic and differencing marketing method to lots of hospitals.

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ISO/IEC 15118기반 V2G 환경에서 전기자동차 유연성 검토 (EV Flexibility Availability for V2G Considering ISO/IEC 15118 Charging Protocol)

  • 이상환;조규상;이상영;김영우;손성용
    • 한국정보전자통신기술학회논문지
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    • 제14권1호
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    • pp.91-97
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    • 2021
  • 전기자동차를 이용하여 계통에 전력을 공급하는 Vehicle to Grid(V2G)의 구현을 위한 통신표준으로 ISO/IEC 15118이 적용되고 있다. 통신 프로토콜에 기반을 두는 전기자동차의 충방전 제어 시에 필연적으로 충방전 실행까지의 시간지연이 발생하게 되는데, 이러한 시간지연은 전력 유연성 공급 측면에서 제한의 요인이 된다. 본 연구에서는 ISO/IEC 15118 기반 V2G 에뮬레이터를 구현하고 전기 자동차 충방전 제어에 따른 반응성을 확인하였다. 실험결과 시간지연은 0.12ms로 나타났으며, 이를 기반으로 현 표준 하에서 참여 가능한 전력 유연성 시장에 대하여 검토하였다.

가정간호 서비스 질 평가를 위한 도구개발연구 (A basic research for evaluation of a Home Care Nursing Delivery System)

  • 김모임;조원정;김의숙;김성규;장순복;유호신
    • 가정∙방문간호학회지
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    • 제6권
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    • pp.33-45
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    • 1999
  • The purpose of this study was to develop a basic framework and criteria for evaluation of quality care provided to patients with the attributes of disease in the home care nursing field, and to provide measurement tools for home health care in the future. The study design was a developmental study for evaluation of hospital-based HCN(home care nursing) in Korea. The study process was as follows: a home care nursing study team of College of Nursing. Yonsei University reviewed the nursing records of 47 patients who were enrolled at Yonsei University Medical Center Home Care Center in March, 1995. Twenty-five patients were insured at that time, were selected from 47 patients receiving home care service for study feasibility with six disease groups; Caesarean Section (C/S), simple nephrectomy, Liver cirrhosis(LC), chronic obstructive pulmonary disease(COPD), Lung cancer or cerebrovascular accident(CVA). In this study, the following items were selected : First step : Preliminary study 1. Criteria and items were selected on the basis of related literature on each disease area. 2. Items were identified by home care nurses. 3. A physician in charge reviewed the criteria and content of selected items. 4. Items were revised through preliminary study offered to both HCN patients and discharged patients from the home care center. Second step : Pretest 1. To verify the content of the items, a pretest was conducted with 18 patients of which there were three patients in each of the six selected disease groups. Third step : Test of reliability and validity of tools 1. Using the collected data from 25 patients with either cis, Simple nephrectomy, LC, COPD, Lung cancer, or CVA. the final items were revised through a panel discussion among experts in medical care who were researchers, doctors, or nurses. 2. Reliability and validity of the completed tool were verified with both inpatients and HCN patients in each of field for researches. The study results are as follows: 1. Standard for discharge with HCN referral The referral standard for home care, which included criteria for discharge with HCN referral and criteria leaving the hospital were established. These were developed through content analysis from the results of an open-ended questionnaire to related doctors concerning characteristic for discharge with HCN referral for each of the disease groups. The final criteria was decided by discussion among the researchers. 2. Instrument for measurement of health statusPatient health status was measured pre and post home care by direct observation and interview with an open-ended questionnaire which consisted of 61 items based on Gorden's nursing diagnosis classification. These included seven items on health knowledge and health management, eight items on nutrition and metabolism, three items on elimination, five items on activity and exercise, seven items on perception and cognition, three items on sleep and rest, three items on self-perception, three items on role and interpersonal relations, five items on sexuality and reproduction, five items on coping and stress, four items on value and religion, three items on family. and three items on facilities and environment. 3. Instrument for measurement of self-care The instrument for self-care measurement was classified with scales according to the attributes of the disease. Each scale measured understanding level and practice level by a Yes or No scale. Understanding level was measured by interview but practice level was measured by both observation and interview. Items for self-care measurement included 14 for patients with a CVA, five for women who had a cis, ten for patients with lung cancer, 12 for patients with COPD, five for patients with a simple nephrectomy, and 11 for patients with LC. 4. Record for follow-up management This included (1) OPD visit sheet, (2) ER visit form, (3) complications problem form, (4) readmission sheet. and (5) visit note for others medical centers which included visit date, reason for visit, patient name, caregivers, sex, age, time and cost required for visit, and traffic expenses, that is, there were open-end items that investigated OPD visits, emergency room visits, the problem and solution of complications, readmissions and visits to other medical institution to measure health problems and expenditures during the follow up period. 5. Instrument to measure patients satisfaction The satisfaction measurement instrument by Reisseer(1975) was referred to for the development of a tool to measure patient home care satisfaction. The instrument was an open-ended questionnaire which consisted of 11 domains; treatment, nursing care, information, time consumption, accessibility, rapidity, treatment skill, service relevance, attitude, satisfaction factors, dissatisfaction factors, overall satisfaction about nursing care, and others. In conclusion, Five evaluation instruments were developed for home care nursing. These were (1)standard for discharge with HCN referral. (2)instrument for measurement of health status, (3)instrument for measurement of self-care. (4)record for follow-up management, and (5)instrument to measure patient satisfaction. Also, the five instruments can be used to evaluate the effectiveness of the service to assure quality. Further research is needed to increase the reliability and validity of instrument through a community-based HCN evaluation.

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정전분무에 의한 고점성 액체의 액적 생성 특성에 관한 실험적 연구 (An Experimental Study on Characteristics of Droplet Generation by Electrospraying for Highly Viscous Liquids)

  • 김상수;구본기
    • 대한기계학회논문집B
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    • 제26권4호
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    • pp.604-613
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    • 2002
  • Generation characteristics of electrospray droplets for highly viscous liquid have been investigated by measuring size distributions of droplets emitted from the Taylor cone using glycerol solutions with various conductivities. Because of very small volatility of glycerol, droplet sizes can be measured by an aerodynamic size spectrometer (TSI Aerosizer DSP) with negligible evaporation of droplets. For highly conducting and viscous liquid, the sizes of the droplets electrosprayed from the Taylor cone are found to be relatively insensitive to applied voltages and the electrosprays assisted by the corona discharge call produce monodisperse droplets as long as the corona intensity is not too high. Near the minimum flow rate where a liquid cone is stable, the spray tends to consist of a one -peak monodisperse distribution of drop lets. However, at high flow rates, the spray bifurcates into bimodal distributions, which are consistent with the result of the previous study for less viscous liquids than our liquids. For liquid flow rates (Q) below 1 nl/s, the measured droplet diameters by the aerosizer are in the range of 0.30 to 1.2 ${\mu}{\textrm}{m}$ for the glycerol solutions. The diameters of monodisperse droplets scale approximately with $r^*=Q_$\tau$(Q$\tau$){^1/3}$ where $r^*$ is a characteristic length and $\tau$is the electrical relaxation time of the fluid. However, when compared with several represe ntative scaling laws, the droplet diameters are two to six factors greater than those predicted by the scaling laws. This may be closely related to the combined effect of the much higher viscosity and the electrical charge on the jet breakup of glycerol so solution.

고속 스위칭 Voltage Down Converter 회로 설계에 대한 연구 (Circuit Design of Voltage Down Converter for High Speed Application)

  • 이승욱;김명식
    • 전자공학회논문지SC
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    • 제38권2호
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    • pp.38-49
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    • 2001
  • 본 논문은 IC chip내에서 전압을 낮추는 목적으로 사용되는 VDC 회로의 주파수 특성을 향상시키기 위한 새로운 회로를 제안한다. 제안된 회로에는 적응 바이어싱 방법을 통해 저전력소모 및 고속동작을 동시에 만족하는 두 개의 센서와 이 센서로 구동되는 3개의 transistor가 부가적으로 첨가되어 구동 transistor의 gate 충.방진 전류를 보상하여 구동회로의 정상동작을 유지시켜준다. 본 연구에 사용된 회로는 $0.62{\mu}m$ N well CMOS 공정을 사용하였으며, H spice simulation 결과, 내부전압의 변화폭은 부하전류가 0에서 $200m{\Lambda}$까지 5ns동안 증가할 경우 약 1.0V로, $200m{\Lambda}$에서 0으로 감소할 경우 약 0.6V로, 내부전압 회복시간은 증가시 7ns, 감소시 10ns로, 일반적인 구동방식에 비해 성능이 향상되었으며 전체 회로에 소모하는 power는 약 1.2mW로 매우 작았다.

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표면 불소화된 미세다공성 PE 격리막의 이차전지 적용을 위한 연구 (Studies on the Secondary Battery Application of the Surface Fluorinated Microporous PE Separator Membranes)

  • 변홍식;김대훈;조현일;이병성;홍병표;이상윤;남상용;서명수;임지원
    • 멤브레인
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    • 제18권1호
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    • pp.75-83
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    • 2008
  • 본 연구에서는 Polyethylene (PE, Asahi) 이차전지용 막의 표면불소화를 통해 기계적 강도 및 열적 안정성과 고출력에서의 안정성을 높이기 위한 연구를 실시하였다. 전자주사현미경(scanning electron microscope, SEM), 접촉각(contact angle)을 통하여 불소가스 노출시간에 따른 막의 표면과 구조의 변화를 관찰하고, 인장강도와 표면 친수성 실험을 통하여 막의 기계적 물성을 확인하였다. 제조된 막의 전기화학적 특성을 확인하기 위하여 충/방전 실험, 수명특성. 고율방전시험을 실시하여 고출력에서 온도에 대한 안정성이 향상되었음을 확인하였다.

리튬 이차전지용 텅스텐 산화물 전해 도금 박막 제조 (Preparation of Electrolytic Tungsten Oxide Thin Films as the Anode in Rechargeable Lithium Battery)

  • 이준우;최우성;신헌철
    • 한국재료학회지
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    • 제23권12호
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    • pp.680-686
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    • 2013
  • Tungsten oxide films were prepared by an electrochemical deposition method for use as the anode in rechargeable lithium batteries. Continuous potentiostatic deposition of the film led to numerous cracks of the deposits while pulsed deposition significantly suppressed crack generation and film delamination. In particular, a crack-free dense tungsten oxide film with a thickness of ca. 210 nm was successfully created by pulsed deposition. The thickness of tungsten oxide was linearly proportional to deposition time. Compositional and structural analyses revealed that the as-prepared deposit was amorphous tungsten oxide and the heat treatment transformed it into crystalline triclinic tungsten oxide. Both the as-prepared and heat-treated samples reacted reversibly with lithium as the anode for rechargeable lithium batteries. Typical peaks for the conversion processes of tungsten oxides were observed in cyclic voltammograms, and the reversibility of the heat-treated sample exceeded that of the as-prepared one. Consistently, the cycling stability of the heat-treated sample proved to be much better than that of the as-prepared one in a galvanostatic charge/discharge experiment. These results demonstrate the feasibility of using electrolytic tungsten oxide films as the anode in rechargeable lithium batteries. However, further works are still needed to make a dense film with higher thickness and improved cycling stability for its practical use.

Activated carbons prepared from mixtures of coal tar pitch and petroleum pitch and their electrochemical performance as electrode materials for electric double-layer capacitor

  • Lee, Eunji;Kwon, Soon Hyung;Choi, Poo Reum;Jung, Ji Chul;Kim, Myung-Soo
    • Carbon letters
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    • 제16권2호
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    • pp.78-85
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    • 2015
  • Activated carbons (ACs) were prepared by activation of coal tar pitch (CTP) in the range of $700^{\circ}C-1000^{\circ}C$ for 1-4 h using potassium hydroxide (KOH) powder as the activation agent. The optimal activation conditions were determined to be a CTP/KOH ratio of 1:4, activation temperature of $900^{\circ}C$, and activation time of 3 h. The obtained ACs showed increased pore size distribution in the range of 1 to 2 nm and the highest specific capacitance of 122 F/g in a two-electrode system with an organic electrolyte, as measured by a charge-discharge method in the voltage range of 0-2.7 V. In order to improve the performance of the electric double-layer capacitor electrode, various mixtures of CTP and petroleum pitch (PP) were activated at the optimal activation conditions previously determined for CTP. Although the specific capacitance of AC electrodes prepared from CTP only and the mixtures of CTP and PP was not significantly different at a current density of 1 A/g, the AC electrodes from CTP and PP mixtures showed outstanding specific capacitance at higher current rates. In particular, CTP-PP61 (6:1 mixture) had the highest specific capacitance of 132 F/g, and the specific capacitance remained above 90% at a high current density of 3 A/g. It was found that the high specific capacitance could be attributed to the increased micro-pore volume of ACs with pore sizes from 1 to 2 nm, and the high power density could be attributed to the increased meso-pore volume.

MATLAB/Simulink를 이용한 오프그리드형 고효율 태양광 충전 시스템 설계 (Design of an Off Grid type High efficiency Solar charging system Using MATLAB/Simulink)

  • 미흐렛 가아브레슬라세 마루;김민;변기식;김관형
    • 한국정보통신학회:학술대회논문집
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    • 한국정보통신학회 2017년도 춘계학술대회
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    • pp.735-737
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    • 2017
  • An Off grid or remote solar electric systems are an energy supply to our home or to our companies without the utility of Grid at all. Off grid solar systems are very important for those who live in remote locations especially for developing countries where getting the electric grid is extremely expensive, inconvenient or for those who doesn't need to pay a monthly bill with the electric bill in general. The main critical components of any solar power system or renewable energy harvesting systems are the energy storage systems and its charge controller system. Energy storage systems are the essential integral part of a solar energy harvesting system and in general for all renewable energy harvesting systems. To provide an optimal solution of both high power density and high energy density at the same time we have to use hybrid energy storage systems (HESS), that combine two or more energy storage technologies with complementary characteristics. In this present work, design and simulation we use two storage systems supercapacitor for high power density and lithium based battery for high energy density. Here the system incorporates fast-response supercapacitors to provide power to manage solar smoothing and uses a battery for load shifting. On this paper discuss that the total energy throughout of the battery is much reduced and the typical thermal stresses caused by high discharge rate responses are mitigated by integrating supercapacitors with the battery storage system. In addition of the above discussion the off grid solar electric energy harvesting presented in this research paper includes battery and supercapacitor management system, MPPT (maximum power point tracking) system and back/boost convertors. On this present work the entire model of off grid electric energy harvesting system and all other functional blocks of that system is implemented in MATLAB Simulink.

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