• 제목/요약/키워드: Persistent current

검색결과 161건 처리시간 0.029초

Design and Implementation of Modified Current Source Based Hybrid DC - DC Converters for Electric Vehicle Applications

  • Selvaganapathi, S.;Senthilkumar, A.
    • Transactions on Electrical and Electronic Materials
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    • 제17권2호
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    • pp.57-68
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    • 2016
  • In this study, we present the modern hybrid system based power generation for electric vehicle applications. We describe the hybrid structure of modified current source based DC - DC converters used to extract the maximum power from Photovoltaic (PV) and Fuel Cell system. Due to reduced dc-link capacitor requirement and higher reliability, the current source inverters (CSI) better compared to the voltage source based inverter. The novel control strategy includes Distributed Maximum Power Point Tracking (DMPPT) for photovoltaic (PV) and fuel cell power generation system. The proposed DC - DC converters have been analyzed in both buck and boost mode of operation under duty cycle 0.5>d, 0.5<d<1 and 0.5<d for capable electric vehicle applications. The proposed topology benefits include one common DC-AC inverter that interposes the generated power to supply the charge for the sharing of load in a system of hybrid supply with photovoltaic panels and fuel cell PEM. An improved control of Direct Torque and Flux Control (DTFC) based induction motor fed by current source converters for electric vehicle.In order to achieve better performance in terms of speed, power and miles per gallon for the expert, to accepting high regenerative braking current as well as persistent high dynamics driving performance is required. A simulation model for the hybrid power generation system based electric vehicle has been developed by using MATLAB/Simulink. The Direct Torque and Flux Control (DTFC) is planned using Xilinx ISE software tool in addition to a Modelsim 6.3 software tool that is used for simulation purposes. The FPGA based pulse generation is used to control the induction motor for electric vehicle applications. FPGA has been implemented, in order to verify the minimal error between the simulation results of MATLAB/Simulink and experimental results.

Development plan for a persistent 1.3 GHz NMR magnet in a new MIRAI project on joint technology for HTS wires/cables in Japan

  • Yanagisawa, Y.;Suetomi, Y.;Piao, R.;Yamagishi, K.;Takao, T.;Hamada, M.;Saito, K.;Ohki, K.;Yamaguchi, T.;Nagaishi, T.;Kitaguchi, H.;Ueda, H.;Shimoyama, J.;Ishii, Y.;Tomita, M.;Maeda, H.
    • 한국초전도저온공학회지:초전도와저온공학
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    • 제20권2호
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    • pp.15-22
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    • 2018
  • The present article briefly overviews the plan for a new project on joint technology for HTS wires/cables and describes the development plan for the world's highest field NMR magnet, which is a major development item in the project. For full-fledged social implementation of superconducting devices, high temperature superconducting (HTS) wire is a key technology since they can be cooled by liquid nitrogen and they can generate a super-high magnetic field of >>24 T at liquid helium temperatures. However, one of the major drawbacks of the HTS wires is their availability only in short lengths of a single piece of wire. This necessitates a number of joints being installed in superconducting devices, resulting in a difficult manufacturing process and a large joint resistance. In Japan, a large-scale project has commenced, including two technical demonstration items: (i) Development of superconducting joints between HTS wires, which are used in the world's highest field 1.3 GHz (30.5 T) NMR magnet in persistent current mode; the joints performance is evaluated based on NMR spectra for proteins. (ii) Development of ultra-low resistive joints between DC superconducting feeder cables for railway systems. The project starts a new initiative of next generation super-high field NMR development as well as that of realization of better superconducting power cables.

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하·폐수내 브롬화 디페닐 에테르(Polybrominated Diphenyl Ether, PBDEs)의 분포 및 제거기술 동향 (Treatment Technologies for Removal of Polybrominated Diphenyl Ethers (PBDEs) from Wastewater)

  • 김민희;현승훈;이원석
    • 한국물환경학회지
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    • 제33권6호
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    • pp.754-768
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    • 2017
  • Polybrominated diphenyl ethers (PBDEs) are a group of industrial aromatic organobromine chemicals that have been used since the 1970s as flame retardants in a wide range of consumer products and articles, including plastics, computers, textiles and upholstery. Commercial PBDEs were added to Annex A of the Stockholm Convention as persistent organic pollutants in May 2009. PBDEs are still frequently found in sludge and effluent from wastewater treatment plants, even though commercial PBDEs were prohibited or voluntarily phased out several years ago. Conventional wastewater treatment processes are not designed to effectively remove PBDEs. This indicates that there is an urgent need for new developments and improvements to enhance upon the treatment techniques which are currently available. Several studies have suggested the potential removal and degradation technologies for PBDEs in wastewater. In this study, the concentrations and compositional profiles of PBDE congeners in sludge and effluent are investigated by analyzing the relevant literature data in relation to their usage patterns in commercial products in North America and South Korea. The strengths and weaknesses of the current PBDEs removal techniques (i.e., biodegradation, zero-valent iron, photolysis, sorption, etc.) are discussed critically. In addition, future research direction regarding the treatment and removal of PBDEs from wastewater is also suggested, based on the literature review.

중년비만 관리를 위한 행동수정요법과 인공지능 기법을 활용한 유연하고 상황에 맞는 격려 방법에 대한 연구 (Soft And Timely Encourgement by AI with Behavior Modification Therapy to Help Middle-Aged Obesity)

  • 정희영;최기원;홍수영;김희철;김대영
    • 한국정보통신학회:학술대회논문집
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    • 한국정보통신학회 2017년도 춘계학술대회
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    • pp.730-732
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    • 2017
  • 비만의 치료와 관리에 있어서 식이요법과 운동요법은 비교적 단기간의 효과는 입증 되었지만, 장기간 체중유지가 되지 못한다는 문제가 있다. 그래서 비만연구가들은 치료의 현장에서 행동수정요법을 활용한다. 그러나 행동수정요법의 식습관 및 생활습관 개선만으론 체중관리에 있어서 지속적인 결과유지는 여전히 큰 문제로 남아 있다. 그래서 본 연구에서는 기존 비만치료의 한계를 조금이나마 해결하고자, 행동수정요법의 장점에 인공지능을 활용한 비만관리를 제안한다. 인공지능 비만관리는 대상자들에게 인공지능으로 테이터화 된 문자메시지를 각자의 상황에 맞게 보내는 프로그램이다. 무엇보다도 인공지능 일대일 맞춤형 비만관리 메시지는 유연한 설득, 격려, 동기부여를 통한 운동지속의 효과를 강화시키는 연구 제안이다.

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산소 후열처리에 따른 Ga2O3/SiC photodetector의 전기 광학적 특성 (Impact of Oxygen Annealing on Deep-level Traps in Ga2O3/SiC Photodetectors)

  • 정승환;이태희;문수영;박세림;이형진;이건희;구상모
    • 전기전자학회논문지
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    • 제27권3호
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    • pp.288-295
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    • 2023
  • 본 연구에서는 radio frequency (RF)-스퍼터링을 이용하여 SiC 기판 위에 Ga2O3 박막을 증착하여 Metal-Semiconductor-Metal (MSM) UV photodetector (PD)를 제작하였고, 산소 후열처리에 따른 PD 성능을 연구하였다. 산소 후열처리된 Ga2O3 박막은 외부 광에 대한 전류의 상당한 증가와 시간 의존성 on/off 광 응답 특성에서 측정된 감소시간이 1.21, 1.12 s로 후열처리를 하지 않은 박막의 감소시간인 1.34, 3.01 s 보다 더 빠른 반응을 보여주었다. 이러한 특성은 산소 후열처리 후의 산소 공공 및 결함 분포 변화에 기인한다. 우리의 연구 결과는 산소 후열처리가 PD 성능 향상에 영향을 미칠 수 있다는 것을 확인하였다.

Cellular Protrusions - Lamellipodia, Filopodia, Invadopodia and Podosomes - and their Roles in Progression of Orofacial Tumours: Current Understanding

  • Alblazi, Kamila Mohamed Om;Siar, Chong Huat
    • Asian Pacific Journal of Cancer Prevention
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    • 제16권6호
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    • pp.2187-2191
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    • 2015
  • Background: Protrusive structures formed by migrating and invading cells are termed lamellipodia, filopodia, invadopodia and podosomes. Lamellipodia and filopodia appear on the leading edges of migrating cells and function to command the direction of the migrating cells. Invadopodia and podosomes are special F-actin-rich matrix-degrading structures that arise on the ventral surface of the cell membrane. Invadopodia are found in a variety of carcinomatous cells including squamous cell carcinoma of head and neck region whereas podosomes are found in normal highly motile cells of mesenchymal and myelomonocytic lineage. Invadopodia-associated protein markers consisted of 129 proteins belonging to different functional classes including WASP, NWASP, cortactin, Src kinase, Arp 2/3 complex, MT1-MMP and F-actin. To date, our current understanding on the role(s) of these regulators of actin dynamics in tumors of the orofacial region indicates that upregulation of these proteins promotes invasion and metastasis in oral squamous cell carcinoma, is associated with poor/worst prognostic outcome in laryngeal cancers, contributes to the persistent growth and metastasis characteristics of salivary gland adenoid cystic carcinoma, is a significant predictor of increased cancer risk in oral mucosal premalignant lesions and enhances local invasiveness in jawbone ameloblastomas.

만성통증의 경감과 치유를 위한 노인요양시설의 긍정적 관심 전환 환경 (Nursing Home Environment with Positive Distraction for Reduction of Chronic Pain and Healing)

  • 정미렴
    • 한국실내디자인학회논문집
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    • 제24권2호
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    • pp.206-216
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    • 2015
  • Majority of the seniors living in nursing homes suffer from persistent chronic pain, which may cause depression and compromised quality of life if untreated. The environment should support them to lift their focus from current pain and worries to the positive feelings and the delight of life. The purpose of this research is to classify the healing environment elements for positive distraction, and analyze 6 international cases to see the current situation. The elements were categorized as follows, based on literature review from both healing spaces and elderly care field: spatial elements(view, natural elements, artificial elements, exercise space, garden), psychological elements(grooming area, space for privacy, meal/drink area, elements for recollection, religious space), social elements(common living area, activity/hoppy room, family/visitor area, information area, local community program space). Analysis on 6 facilities showed that each elements were reflected to designed relatively well. New inventions from workers who think distraction is important were also introduced. Healing environment for positive distraction requires delicate touch, derived from understanding characteristics and situation of the residing elderly individuals. Technology update is also significant, from audio books to virtual reality devices, since cultural life of nursing home is far behind from what the others enjoy now.

The fabrication of $MgB_2$/SUS Tapes by PIT Process

  • 송규정;이남진;장현만;하홍수;하동우
    • Progress in Superconductivity
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    • 제3권2호
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    • pp.213-217
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    • 2002
  • We have fabricated successfully single-filament composite $MgB_2$/SUS tapes, as an ultrarobust conductor type. The fabrication of the $MgB_2$/SUS tapes was performed by power-in-tube (PIT) process such as swaging and cold rolling. The critical transition temperatures $T_{c}$~38.5 K and ~36 K were observed for the sintered and the nonsintered $MgB_2$/SUS tapes, respectively In addition, the isothermal magnetization M(H) of the sintered $MgB_2$/SUS tapes was measured at temperatures T (between 5 and 50 K) in fields up to 6 T, employing a PPMS-9 (Quantum Design). The persistent current density (J$T_{P}$) values were obtained from the M(H) data, using Bean model, fur the sintered $MgB_2$/SUS tapes. The estimated values were higher than ~ 6$\times$ $10^{5}$ $A/\textrm{cm}^2$ at T = 5 K, with H : 0 G. We also investigated the cross section of the sintered tapes, by using SEM and EDX. An evidence of weak reaction on boundary between $MgB_2$ and SUS tube is found in the SEM and EDX.X.X.X.

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Effects of Hydrogen Peroxide on Neuronal Excitability and Synaptic Transmission in Rat Substantia Gelatinosa Neurons

  • Son, Yong;Chun, Sang-Woo
    • International Journal of Oral Biology
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    • 제32권4호
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    • pp.153-160
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    • 2007
  • The superficial dorsal horn, particularly substantia gelatinosa (SG) in the spinal cord, receives inputs from small-diameter primary afferents that predominantly convey noxious sensation. Reactive oxygen species (ROS) are toxic agents that may be involved in various neurodegenerative diseases. Recent studies indicate that ROS are also involved in persistent pain through a spinal mechanism. In the present study, whole cell patch clamp recordings were carried out on SG neurons in spinal cord slice of young rats to investigate the effects of hydrogen peroxide on neuronal excitability and excitatory synaptic transmission. In current clamp condition, tert-buthyl hydroperoxide (t-BuOOH), an ROS donor, depolarized membrane potential of SG neurons and increased the neuronal firing frequencies evoked by depolarizing current pulses. When slices were pretreated with phenyl-N-tert-buthylnitrone (PBN) or ascorbate, ROS scavengers, t-BuOOH did not induce hyperexcitability. In voltage clamp condition, t-BuOOH increased the frequency and amplitude of spontaneous excitatory postsynaptic currents (sEPSCs), and monosynaptically evoked excitatory postsynaptic currents (eEPSCs) by electrical stimulation of the ipsilateral dorsal root. These data suggest that ROS generated by peripheral nerve injury can modulate the excitability of the SG neurons via pre- and postsynaptic actions.

Current Trends for Treating Lateral Epicondylitis

  • Kim, Gyeong Min;Yoo, Seung Jin;Choi, Sungwook;Park, Yong-Geun
    • Clinics in Shoulder and Elbow
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    • 제22권4호
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    • pp.227-234
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    • 2019
  • Lateral epicondylitis, also known as 'tennis elbow', is a degenerative rather than inflammatory tendinopathy, causing chronic recalcitrant pain in elbow joints. Although most patients with lateral epicondylitis resolve spontaneously or with standard conservative management, few refractory lateral epicondylitis are candidates for alternative non-operative and operative modalities. Other than standard conservative treatments including rest, analgesics, non-steroidal anti-inflammatory medications, orthosis and physical therapies, nonoperative treatments encompass interventional therapies include different types of injections, such as corticosteroid, lidocaine, autologous blood, platelet-rich plasma, and botulinum toxin, which are available for both short-term and long-term outcomes in pain resolution and functional improvement. In addition, newly emerging biologic enhancement products such as bone marrow aspirate concentrate and autologous tenocyte injectates are also under clinical use and investigations. Despite all non-operative therapeutic trials, persistent debilitating pain in patients with lateral epicondylitis for more than 6 months are candidates for surgical treatment, which include open, percutaneous, and arthroscopic approaches. This review addresses the current updates on emerging non-operative injection therapies as well as arthroscopic intervention in lateral epicondylitis.