• Title/Summary/Keyword: Magnetic Guideline

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Study on the Design Constraints of the Wall-Climbing Mobile Robot Using Permanent Magnetic Wheels (Part 1 - Design Guideline) (영구 자석 바퀴를 이용한 벽면 이동 로봇의 설계시의 제약 사항들에 대한 연구 (Part 1 - 설계지침))

  • 한승철;이화조;김은찬
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.9
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    • pp.69-76
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    • 2004
  • Most tasks of the large vertical or ceiling structures have been carried out by human power. Those tasks require us much operation costs and times, safety devices, etc. So the need of automation for those tasks have been rising. That automation needs a wall-climbing mobile vehicle. Most former researches are things about attachment devices and moving mechanisms. A wall-climbing mobile vehicle must be designed by a method different from the case of the vehicle of the horizontal environment. That is because gravity acts as a negative role on the stability of a wall-climbing vehicle. In this thesis, the particular shape characteristics of a wall-climbing mobile vehicle are derived by the wall-environment modeling. In addition, some design constraints of the permanent magnetic wheel as an attachment device was studied. According to those requirements and constraints, one specific wall-climbing mobile vehicle was designed and some experiments were made on the attachment ability of that vehicle.

760 V-Class DC Switch Breaking Characteristics Using Tandem Type Magnet Extinguisher (탠덤형 자석 소호기를 사용한 760V급 직류 개폐기의 차단 특성)

  • Kim, Hyosung
    • The Transactions of the Korean Institute of Power Electronics
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    • v.27 no.3
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    • pp.175-179
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    • 2022
  • Magnetic arc extinguishing technology is effective as an extinguishing device for low-voltage direct current (DC) circuit breakers with a resistive load of ≤4 kW. The separation distance between the magnet and the electrical contact must be shortened to increase the magnetic arc extinguishing force. However, if the magnet is installed too close to the electrical contact points, the magnet is exposed to high temperatures due to the arc current generated when the load current is cut off and the magnetism is lost. To solve this problem, the effective magnetic flux density at the electrical contact can be maintained high by placing the arc extinguishing magnet in a tandem structure with the electrical contact point between them, and the proper separation distance between the contact points and the magnet can be maintained. In addition, an electric arc extinguishing technology that emits arc energy using a series circuit of diode and resistor is used to suppress the continuous arc voltage generated by the inductive load. For the proposed circuit breaker, the breaking characteristics are analyzed through the breaking test for the DC load of the 760 V level, the load power of 4 kW, and the time constant of 5 ms, and an appropriate arc extinguishing design guideline is proposed.

Emerging Role of Hepatobiliary Magnetic Resonance Contrast Media and Contrast-Enhanced Ultrasound for Noninvasive Diagnosis of Hepatocellular Carcinoma: Emphasis on Recent Updates in Major Guidelines

  • Tae-Hyung Kim;Jeong Hee Yoon;Jeong Min Lee
    • Korean Journal of Radiology
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    • v.20 no.6
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    • pp.863-879
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    • 2019
  • Hepatocellular carcinoma (HCC) can be noninvasively diagnosed on the basis of its characteristic imaging findings of arterial phase enhancement and portal/delayed "washout" on computed tomography (CT) and magnetic resonance imaging (MRI) in cirrhotic patients. However, different specific diagnostic criteria have been proposed by several countries and major academic societies. In 2018, major guideline updates were proposed by the Association for the Study of Liver Diseases, European Association for the Study of the Liver (EASL), Korean Liver Cancer Association and National Cancer Center (KLCA-NCC) of Korea. In addition to dynamic CT and MRI using extracellular contrast media, these new guidelines now include magnetic resonance imaging (MRI) using hepatobiliary contrast media as the first-line diagnostic test, while the KLCA-NCC and EASL guidelines also include contrast-enhanced ultrasound (CEUS) as the second-line diagnostic test. Therefore, hepatobiliary MR contrast media and CEUS will be increasingly used for the noninvasive diagnosis and staging of HCC. In this review, we discuss the emerging role of hepatobiliary phase MRI and CEUS for the diagnosis of HCC and also review the changes in the HCC diagnostic criteria in major guidelines, including the KLCA-NCC practice guidelines version 2018. In addition, we aimed to pay particular attention to some remaining issues in the noninvasive diagnosis of HCC.

Guidelines for Cardiovascular Magnetic Resonance Imaging from the Korean Society of Cardiovascular Imaging (KOSCI) - Part 2: Interpretation of Cine, Flow, and Angiography Data

  • Lee, Jae Wook;Hur, Jee Hye;Yang, Dong Hyun;Lee, Bae Young;Im, Dong Jin;Hong, Su Jin;Kim, Eun Young;Park, Eun-Ah;Jo, Yeseul;Kim, Jeong Jae;Park, Chul Hwan;Yong, Hwan Seok
    • Investigative Magnetic Resonance Imaging
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    • v.23 no.4
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    • pp.316-327
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    • 2019
  • Cardiovascular magnetic resonance imaging (CMR) is expected to be increasingly used in Korea due to technology advances and the expanded national insurance coverage of these tests. For improved patient care, it is crucial not only that CMR images are properly acquired but that they are accurately interpreted by well-trained personnel. In response to the increased demand for CMR, the Korean Society of Cardiovascular Imaging (KOSCI) has issued interpretation guidelines in conjunction with the Korean Society of Radiology (KSR). KOSCI has also created a formal Committee on CMR Guidelines to write updated practices. The members of this Committee review previously published interpretation guidelines and discuss the patterns of CMR use in Korea.

MREIT of Postmortem Swine Legs using Carbon-hydrogel Electrodes

  • Minhas, Atul S.;Jeong, Woo-Chul;Kim, Young-Tae;Kim, Hyung-Joong;Lee, Tae-Hwi;Woo, Eung-Je
    • Journal of Biomedical Engineering Research
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    • v.29 no.6
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    • pp.436-442
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    • 2008
  • Magnetic resonance electrical impedance tomography(MREIT) has been suggested to produce cross-sectional conductivity images of an electrically conducting object such as the human body. In most previous studies, recessed electrodes have been used to inject imaging currents into the object. An MRI scanner was used to capture induced magnetic flux density data inside the object and a conductivity image reconstruction algorithm was applied to the data. This paper reports the performance of a thin and flexible carbon-hydrogel electrode that replaces the bulky and rigid recessed electrode in previous studies. The new carbon-hydrogel electrode produces a negligible amount of artifacts in MR and conductivity images and significantly simplifies the experimental procedure. We can fabricate the electrode in different shapes and sizes. Adding a layer of conductive adhesive, we can easily attach the electrode on an irregular surface with an excellent contact. Using a pair of carbon-hydrogel electrodes with a large contact area, we may inject an imaging current with increased amplitude primarily due to a reduced average current density underneath the electrodes. Before we apply the new electrode to a human subject, we evaluated its performance by conducting MREIT imaging experiments of five swine legs. Reconstructed conductivity images of the swine legs show a good contrast among different muscles and bones. We suggest a future study of human experiments using the carbon-hydrogel electrode following the guideline proposed in this paper.

Real-Time Control of Networked Control Systems via Ethernet

  • Ji Kun;Kim Won-jong
    • International Journal of Control, Automation, and Systems
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    • v.3 no.4
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    • pp.591-600
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    • 2005
  • In this paper, we discuss real-time control of networked control systems (NCSs) and practical issues in the choice of the communication networks for this purpose. An appropriate integration of control systems, real-time environments, and network communication systems allows the optimization of the quality-of-control (QoC) in NCSs. We compare several prevailing network types that may be used in control applications to offer a guideline of choosing a proper network. A real-time operating environment is also presented as an important ingredient of NCS design. To evaluate its feasibility and effectiveness, a real-time NCS containing a ball magnetic levitation (Maglev) setup is implemented via an Ethernet. Based on the experimental results, it is concluded in this paper that real-time control via Ethernet is a practical and feasible solution to NCS design.

Analytical Techniques Using ICP-MS for Clinical and Biological Analysis

  • Ko, Jungaa;Lim, H. B.
    • Mass Spectrometry Letters
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    • v.6 no.4
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    • pp.85-90
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    • 2015
  • This article reviews recent analytical techniques using inductively coupled plasma-mass spectrometry (ICP-MS) immunoassay for clinical and bio analysis. We classified the techniques into two categories, direct and indirect analysis, which depend upon a guideline of whether tagging materials are used or not. Direct analysis is well known, and generally used in conjunction with various other techniques, such as laser ablation, chromatographic separations, etc. Recently, indirect analysis using tagging elements has intensively been discussed because of its importance in future applications to bio and clinical analysis, including environmental and food industries. The method has shown advantages of multiplex detection, excellent sensitivity, and short analysis time owing to signal amplification and magnetic separation. Now, it expands the application field from small biomolecules to large cells.

Investigation of Validity of Exposure Limits for Electromagnetic Field in RF Band (RF 대역 전자계 노출기준의 타당성에 관한 연구)

  • 백정기
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.10 no.4
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    • pp.520-529
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    • 1999
  • Exposure limits for human protection are determined by converting basic limits for induced current, SAR(specific absorption rate), or power density, which are based upon biological effects, to measurable electric and magnetic field intensities. As a part of studies for the establishment of a domestic guideline for exposure limits, the validity of the exposure limits of five representative guidelines or standards, which are derived from basic limits, are investigated in this paper, using the published results for coupling mechanisms of electromagnetic field into a human body, and problems in each standard are analyzed and compared with each other.

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Optimal Design of the Igniter Transformer for the Automotive HID Lamp Ballast (순시 재점등을 위한 소형 HID램프 이그니터 변압기에 대한 연구)

  • Kim W.S.;Lee I.K.;Kim C.G.;Lee G.C.;Cho B.H.
    • Proceedings of the KIPE Conference
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    • 2004.11a
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    • pp.111-115
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    • 2004
  • In this paper, the requirements for the HID lamp igniter transformer capable of hot strike are described. A small size high voltage (HV) transformer composed of a Rod type ferrite core and aluminum foil is designed. The Electro Magnetic characteristics are simulated with Finite Element Methodology (FEM). The design guideline of the HV transformer that produces an output voltage with a peak value of 25kV and a pulse width of larger than loons for a 35W automotive HID ballast prototype is discussed as an illustrative example.

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무선 전력 전송 시스템에서의 전자파 연구 동향

  • Kim, Jong-Hun;Kim, Ji-Seong;An, Seung-Yeong;Kim, Jeong-Ho
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.27 no.1
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    • pp.54-65
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    • 2016
  • 상용화되는 무선 전력 전송 시스템이 점점 더 증가하고 있다. 휴대폰과 같은 모바일 기기의 무선 충전 기술은 이제 자동차에서까지 상용화 제품의 출시가 되기 시작하였다. 이렇게 무선 전력 전송 시스템의 상용화기 진행됨에 따라, 무선 전력 전송 시스템에서 방사되는 전자파에 관한 일반 시민들의 우려도 증가하고 있으므로, 무선 전력 전송 시스템에서 방사되는 전자파를 축소시키는 기술의 연구 개발은 지속적으로 진행되어야 한다. 가장 먼저 무선 전력 전송 시스템의 구성을 소개하였고, 13개의 설계 입력 변수와 17개의 출력 파라미터를 언급하였다. 전자파 노이즈의 방사 원리 및 허용되는 전자파의 세기에 관하여 소개하면서 ICNIRP guideline과 CISPR standard 예제를 다루었다. 마지막으로 무선 전력 전송 시스템에서 방사되는 전자파의 축소 기술에 관한 연구 개발 사례를 다루었다. Electromagnetic shielding, Magnetic-field cancelation, LC filtering, Decoupled inductor, Spread spectrum 등의 기술을 적용하여 무선 전력 전송 시스템에서 방사되는 전자파 노이즈를 효과적으로 축소시킬 수 있으며, 앞으로도 무선 전력 전송 시스템에서 방사되는 전자파 노이즈를 축소시키기 위한 연구 개발이 지속적으로 진행될 것으로 기대한다.