• Title/Summary/Keyword: Moving Core

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Cogging Force Verification of the Back-yoke Length of a Moving-coil-type Slotless Linear Synchronous Motor

  • Kim, Yong-Jae;Jung, Sang-Yong
    • Journal of Magnetics
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    • v.14 no.1
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    • pp.47-51
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    • 2009
  • The coreless linear synchronous motor (coreless LSM) has been widely used as a driving source of semiconductor production processes for machine speeding up, positioning accuracy and simple maintenance. However, this coreless LSM suffers the disadvantage of decreased thrust force created by the leakage of magnetic flux. With the goal of increasing the generated thrust force and decreasing the cogging force, the slot of the core part was removed and a moving-coil-type slotless LSM (moving-coil-type slotless LSM) is proposed in this paper. Although this moving-coil-type slotless LSM with a back-yoke at the primary side demonstrated an increase in the generated thrust force, it remained capable of generating the cogging force when the primary side was moved due to the position between the permanent magnet and the back-yoke. Therefore, we attempted to decrease the cogging force of the moving-coil-type slotless LSM. We found that the back-yoke length at the primary side needs to be made $0.5{\tau}$ longer than the integral multiple of the magnetic pole pitch in order to decrease the cogging force created by the moving-coil-type slotless LSM.

Effect of the Perpendicular Magnetic Field and Nonadiabatic Spin-transfer Torque on the Vortex Dynamics

  • Moon, Jung-Hwan;Lee, Kyung-Jin
    • Journal of Magnetics
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    • v.13 no.4
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    • pp.157-159
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    • 2008
  • The effect of the perpendicular field on the trajectory of a vortex core driven by spin-transfer torque was investigated using micromagnetic simulations. The trajectory of the vortex core was staggered due to distortions of the moving vortex core. The core trajectory was affected by both the perpendicular field and ${\beta}$ value, which is the relative magnitude of nonadiabatic spin torque to the adiabatic spin torque. This suggests that the effect of the perpendicular field should be considered when examining a vortex core trajectory affected by ${\beta}$.

Core design study of the Wielenga Innovation Static Salt Reactor (WISSR)

  • T. Wielenga;W.S. Yang;I. Khaleb
    • Nuclear Engineering and Technology
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    • v.56 no.3
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    • pp.922-932
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    • 2024
  • This paper presents the design features and preliminary design analysis results of the Wielenga Innovation Static Salt Reactor (WISSR). The WISSR incorporates features that make it both flexible and inherently safe. It is based on innovative technology that controls a nuclear reactor by moving molten salt fuel into or out of the core. The reactor is a low-pressure, fast spectrum transuranic (TRU) burner reactor. Inherent shutdown is achieved by a large negative reactivity feedback of the liquid fuel and by the expansion of fuel out of the core. The core is made of concentric, thin annular fuel chambers containing molten fuel salt. A molten salt coolant passes between the concentric fuel chambers to cool the core. The core has both fixed and variable volume fuel chambers. Pressure, applied by helium gas to fuel reservoirs below the core, pushes fuel out of a reservoir and up into a set of variable volume chambers. A control system monitors the density and temperature of the fuel throughout the core. Using NaCl-(TRU,U)Cl3 fuel and NaCl-KCl-MgCl2 coolant, a road-transportable compact WISSR core design was developed at a power level of 1250 MWt. Preliminary neutronics and thermal-hydraulics analyses demonstrate the technical feasibility of WISSR.

Core Experiments for Standardization of Internet of Media Things (미디어사물인터넷의 국제표준화를 위한 핵심 실험)

  • Jeong, Min Hyuk;Lee, Gyeong Sik;Kim, Sang Kyun
    • Journal of Broadcast Engineering
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    • v.22 no.5
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    • pp.579-588
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    • 2017
  • Recently, due to the development of network environment, the internet market has been expanding, so it is necessary to standardize the data format and API to exchange information among objects. Therefore, MPEG (Moving Picture Expert Group), an international standardization organization, is establishing the MPEG-IoMT (ISO/IEC 23093) project to standardize the Internet of Things. MPEG-IoMT establishes Core Experiment (CE) and discusses overall data exchange such as data exchange procedure, markup language and communication method. In this paper, core experiments 1, 2, 4, and 5 of the core experiments of MPEG-IoMT will be discussed. The performance information of the sensor, the sensor data, the performance information of the driver, and the exchange procedure of the control command are explained and the exchange of the media additional data is discussed. We compare the markup language and communication method through experiment.

Driving Characteristic for Moving flat core LOA (가동 평판 철심형 LOA의 구동 특성)

  • Jang, S.M.;Lee, D.H.;Kwon, C.;Park, N.H.
    • Proceedings of the KIEE Conference
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    • 2001.07b
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    • pp.745-747
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    • 2001
  • This paper deals with the dynamic characteristics of flat core LOA. The LOA system was represented by the voltage equation of coil and the mechanical equation of motion. Also, driving system was simply composed voltage source inverter and generates square-wave. It is measured that dynamic characteristic vary as square-wave.

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Analysis of fluctuations in ex-core neutron detector signal in Krško NPP during an earthquake

  • Tanja Goricanec;Andrej Kavcic;Marjan Kromar;Luka Snoj
    • Nuclear Engineering and Technology
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    • v.56 no.2
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    • pp.575-600
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    • 2024
  • During an earthquake on December 29th 2020, the Krško NPP automatically shutdown due to the trigger of the negative neutron flux rate signal on the power range nuclear instrumentation. From the time course of the detector signal, it can be concluded that the fluctuation in the detector signal may have been caused by the mechanical movement of the ex-core neutron detectors or the pressure vessel components rather than the actual change in reactor power. The objective of the analysis was to evaluate the sensitivity of the neutron flux at the ex-core detector position, if the detector is moved in the radial or axial direction. In addition, the effect of the core barrel movement and core inside the baffle movement in the radial direction were analysed. The analysis is complemented by the calculation of the thermal and total neutron flux gradient in radial, axial and azimuthal directions. The Monte Carlo particle transport code MCNP was used to study the changes in the response of the ex-core detector for the above-mentioned scenarios. Power and intermediate-range detectors were analysed separately, because they are designed differently, positioned at different locations, and have different response characteristics. It was found that the movement of the power range ex-core detector has a negligible effect on the value of the thermal neutron flux in the active part of the detector. However, the radial movement of the intermediate-range detector by 5 cm results in 7%-8% change in the thermal neutron flux in the active part of the intermediate-range detector. The analysis continued with an evaluation of the effects of moving the entire core barrel on the ex-core detector response. It was estimated that the 2 mm core barrel radial oscillation results in ~4% deviation in the power and intermediate-range detector signal. The movement of the reactor core inside baffle can contribute ~6% deviation in the ex-core neutron detector signal. The analysis showed that the mechanical movement of ex-core neutron detectors cannot explain the fluctuations in the ex-core detector signal. However, combined core barrel and reactor core inside baffle oscillations could be a probable reason for the observed fluctuations in the ex-core detector signal during an earthquake.

SNARE Assembly and Membrane Fusion: A Paramagnetic Electron Magnetic Resonance Study

  • Kweon, Dae-Hyuk
    • Proceedings of the Korean Biophysical Society Conference
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    • 2003.06a
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    • pp.32-32
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    • 2003
  • In the neuron, SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptors) assembly plays a central role in driving membrane fusion, a required process for neurotransmitter release. In the cytoplasm, vesicular SNARE VAMP2 (vesicle-associated membrane protein 2) engages with two plasma membrane SNAREs syntaxin 1A and SNAP-25 (synaptosome-associated protein of 25 kDa) to form the core complex that bridges two membranes. While various factors regulate SNARE assembly, the membrane also plays the regulatory role by trapping VAMP2 in the membrane. The fluorescence and EPR analyses revealed that the insertion of seven C-terminal core-forming residues into the membrane controls complex formation of the entire core region, even though preceding 54 core-forming residues are fully exposed and freely moving. When two interfacial Trp residues in this region were replaced with hydrophilic serine residues, the mutation supported rapid complex formation.

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Implementation of NON-ROS remote control software of TurtleBot 2 based Windows 10 IoT core (Windows 10 IoT Core 기반 Non-ROS TurtleBot2용 원격 제어 소프트웨어 구현)

  • Onesphore, Ingabire;Kim, Minyoung;Jang, Jongwook
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2019.05a
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    • pp.111-114
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    • 2019
  • This paper intends to implement a software that controls TurtleBot 2 remotely. The moving of the robot TurtleBot 2 can be controlled using command control based on Windows 10 IoT core instead of the Robot Operating System (ROS). The implemented software allows the user to move remotely TurtleBot 2 in any specified direction and perform the monitoring such as reading feedback data from the robot. Through TCP/IP and serial communication technology, TurtleBot 2 can successfully receive command control and send feedback to the user. Using C# programming language, two Universal Windows Platform apps (client app and server app) have been implemented to allow communication between the user and TurtleBot 2. The result of this implementation has been verified and tested in an indoor platform.

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Preliminary Analysis on IASCC Sensitivity of Core Shroud in Reactor Pressure Vessel (원자로 노심 쉬라우드의 조사유기응력부식균열 민감도 예비 분석)

  • Kim, Jong-Sung;Park, Chang Je
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.15 no.2
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    • pp.58-63
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    • 2019
  • This paper presents preliminary analysis and results on IASCC sensitivity of a core shroud in the reactor pressure vessel. First, neutron irradiation flux distribution of the reactor internals was calculated by using the Monte Carlo simulation code, MCNP6.1 and the nuclear data library, ENDF/B-VII.1. Second, based on the neutron irradiation flux distribution, temperature and stress distributions of the core shroud during normal operation were determined by performing finite element analysis using the commercial finite element analysis program, ABAQUS, considering irradiation aging-related degradation mechanisms. Last, IASCC sensitivity of the core shroud was assessed by using the IASCC sensitivity definition of EPRI MRP-211 and the finite element analysis results. As a result of the preliminary analysis, it was found that the point at which the maximum IASCC sensitivity is derived varies over operating time, initially moving from the shroud plate located in the center of the core to the top shroud plate-ring connection brace over operating time. In addition, it was concluded that IASCC will not occur on the core shroud even after 60 years of operation (40EFPYs) because the maximum IASCC sensitivity is less than 0.5.

Dynamic Characteristics of Moving Coil Linear Oscillatory Actuator Considering the Variable Inductance and Push/pull Effects (가동차 위치에 따른 인덕턴스 변화와 Push/Pull 효과를 고려한 가동코일형 LOA의 동특성)

  • Jeong, Sang-Sub;Jang, Seok-Myeong
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.50 no.7
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    • pp.307-314
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    • 2001
  • A moving coil linear oscillatory actuator is consisted of the NdFeB permanent magnets with high specific energy as the stator, a coil-wrapped nonmagnetic hollow rectangular structure and an iron core as a pathway for magnetic flux. The variation of mover position and the consequent changes of coil flux path affect the coil inductance, because coil flux leaks at the open region of LOA stator. The interaction between permanent magnet and armature field is to shift the airgap flux density variation due to the magnet alone by a certain amount. The unbalanced reciprocation force due to armature reaction field decreases the advantage of moving coil LOA, such as a high degree of linearity and controllability in the force ad motion control. This paper firstly describes the coil inductance, the deviation of flux density, and the unbalanced reciprocation force, which are derived form the permeance model of LOA. Secondly, the analytical method are verified using the 2D finite element method and tests. Finally, the dynamic simulation algorithm taking the armature reaction effect and variable inductance into account, is proposed and confirmed through the experiment.

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