The Experts below are selected from a list of 33480 Experts worldwide ranked by ideXlab platform
Nynke H Dekker - One of the best experts on this subject based on the ideXlab platform.
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Magnetic Torque tweezers measuring torsional stiffness in dna and reca dna filaments
Nature Methods, 2010Co-Authors: Jan Lipfert, Jacob W J Kerssemakers, Tessa Jager, Nynke H DekkerAbstract:Magnetic Torque tweezers are used to directly measure the torsional stiffness of single molecules of bare DNA and RecA filaments. We introduce Magnetic Torque tweezers, which enable direct single-molecule measurements of Torque. Our measurements of the effective torsional stiffness C of dsDNA indicated a substantial force dependence, with C = ∼40 nm at low forces up to C = ∼100 nm at high forces. The initial torsional stiffness of RecA filaments was nearly twofold larger than that for dsDNA, yet at moderate Torques further build-up of torsional strain was prevented.
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Magnetic Torque tweezers measuring torsional stiffness in dna and reca dna filaments
Nature Methods, 2010Co-Authors: Jan Lipfert, Jacob W J Kerssemakers, Tessa Jager, Nynke H DekkerAbstract:Magnetic Torque tweezers are used to directly measure the torsional stiffness of single molecules of bare DNA and RecA filaments.
Seok-myeong Jang - One of the best experts on this subject based on the ideXlab platform.
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Torque analysis and measurements of a permanent magnet type eddy current brake with a halbach magnet array based on analytical Magnetic field calculations
Journal of Applied Physics, 2014Co-Authors: Mingyu Park, Hyeonjae Shin, Jangyoung Choi, Seok-myeong JangAbstract:This paper presents the Torque analysis and measurements of a permanent magnet (PM) type eddy current brake (ECB) with a Halbach magnet array based on analytical Magnetic field calculations. On the basis of a Magnetic vector potential and using a two-dimensional (2D) polar coordinate system, the analytical solution for Magnetic flux density, including the eddy current reaction is evaluated. Based on these solutions, the Magnetic Torque is also determined analytically. A 2D finite element analysis is employed to validate the method used. Practical issues in the analytical study of the PM type ECBs, such as the maximum braking Torque, the required rotor speed, and the segment-dependent, are fully discussed. Finally, the braking Torque as a function of the rotor speed is measured to verify the results of the analytical study.
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analytical Magnetic Torque calculations and experimental testing of radial flux permanent magnet type eddy current brakes
Journal of Applied Physics, 2012Co-Authors: Jangyoung Choi, Seok-myeong JangAbstract:This paper reports on analytical Magnetic Torque calculations and experimental tests of a radial flux permanent magnet (RFPM)-type eddy current brake (ECB). Analytical solutions for permanent magnet-generated Magnetic fields that consider the eddy current reaction are obtained by using a Magnetic vector potential and a two dimensional (2D) polar coordinate system. On the basis of these solutions, the analytical expressions for a Magnetic Torque are also derived. All analytical results are validated extensively by non-linear finite element calculations. In particular, Magnetic Torque measurements are obtained in tests to confirm the analyses. Finally, practical issues related to the analytical study of RFPM-type ECBs are fully discussed.
Bradley J. Nelson - One of the best experts on this subject based on the ideXlab platform.
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behavior of rotating Magnetic microrobots above the step out frequency with application to control of multi microrobot systems
Applied Physics Letters, 2014Co-Authors: Arthur W Mahoney, Bradley J. Nelson, Nathan D Nelson, Kathrin E Peyer, Jake J. AbbottAbstract:This paper studies the behavior of rotating Magnetic microrobots, constructed with a permanent magnet or a soft ferromagnet, when the applied Magnetic field rotates faster than a microrobot's step-out frequency (the frequency requiring the entire available Magnetic Torque to maintain synchronous rotation). A microrobot's velocity dramatically declines when operated above the step-out frequency. As a result, it has generally been assumed that microrobots should be operated beneath their step-out frequency. In this paper, we report and demonstrate properties of a microrobot's behavior above the step-out frequency that will be useful for the design and control of multi-microrobot systems.
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modeling Magnetic Torque and force for controlled manipulation of soft Magnetic bodies
IEEE Transactions on Robotics, 2007Co-Authors: Jake J. Abbott, Michael P. Kummer, Olgaç Ergeneman, Ann M. Hirt, Bradley J. NelsonAbstract:We calculate the Torque and force generated by an arbitrary Magnetic field on an axially symmetric soft-Magnetic body. We consider the magnetization of the body as a function of the applied field, using a continuous model that unifies two disparate Magnetic models. The continuous Torque and force follow. The model is verified experimentally, and captures the often neglected region between weak and saturating fields, where interesting behavior is observed. We provide the field direction to maximize Torque for a given field magnitude. We also find an absolute maximum Torque, for a given body geometry and material, which can be generated with relatively weak applied fields. This paper is aimed at those interested in systems-level analysis, simulation, and real-time control of soft-Magnetic bodies.
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Modeling Magnetic Torque and force for controlled manipulation of soft-Magnetic bodies
IEEE Transactions on Robotics, 2007Co-Authors: Jake J. Abbott, Michael P. Kummer, Olgaç Ergeneman, Ann M. Hirt, Bradley J. NelsonAbstract:We calculate the Torque and force generated by an arbitrary Magnetic field on an axially symmetric soft-Magnetic body. We consider the magnetization of the body as a function of the applied field, using a continuous model that unifies two disparate Magnetic models. The continuous Torque and force follow. The model is verified experimentally, and captures the often-neglected region between weak and saturating fields, where interesting behavior is observed. We provide the optimal field direction for a given field magnitude. We find a maximum possible Torque, which can be generated with relatively weak applied fields. This paper facilitates systems-level analysis, simulation, and real-time control of soft-Magnetic bodies.
Jake J. Abbott - One of the best experts on this subject based on the ideXlab platform.
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behavior of rotating Magnetic microrobots above the step out frequency with application to control of multi microrobot systems
Applied Physics Letters, 2014Co-Authors: Arthur W Mahoney, Bradley J. Nelson, Nathan D Nelson, Kathrin E Peyer, Jake J. AbbottAbstract:This paper studies the behavior of rotating Magnetic microrobots, constructed with a permanent magnet or a soft ferromagnet, when the applied Magnetic field rotates faster than a microrobot's step-out frequency (the frequency requiring the entire available Magnetic Torque to maintain synchronous rotation). A microrobot's velocity dramatically declines when operated above the step-out frequency. As a result, it has generally been assumed that microrobots should be operated beneath their step-out frequency. In this paper, we report and demonstrate properties of a microrobot's behavior above the step-out frequency that will be useful for the design and control of multi-microrobot systems.
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modeling Magnetic Torque and force for controlled manipulation of soft Magnetic bodies
IEEE Transactions on Robotics, 2007Co-Authors: Jake J. Abbott, Michael P. Kummer, Olgaç Ergeneman, Ann M. Hirt, Bradley J. NelsonAbstract:We calculate the Torque and force generated by an arbitrary Magnetic field on an axially symmetric soft-Magnetic body. We consider the magnetization of the body as a function of the applied field, using a continuous model that unifies two disparate Magnetic models. The continuous Torque and force follow. The model is verified experimentally, and captures the often neglected region between weak and saturating fields, where interesting behavior is observed. We provide the field direction to maximize Torque for a given field magnitude. We also find an absolute maximum Torque, for a given body geometry and material, which can be generated with relatively weak applied fields. This paper is aimed at those interested in systems-level analysis, simulation, and real-time control of soft-Magnetic bodies.
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Modeling Magnetic Torque and force for controlled manipulation of soft-Magnetic bodies
IEEE Transactions on Robotics, 2007Co-Authors: Jake J. Abbott, Michael P. Kummer, Olgaç Ergeneman, Ann M. Hirt, Bradley J. NelsonAbstract:We calculate the Torque and force generated by an arbitrary Magnetic field on an axially symmetric soft-Magnetic body. We consider the magnetization of the body as a function of the applied field, using a continuous model that unifies two disparate Magnetic models. The continuous Torque and force follow. The model is verified experimentally, and captures the often-neglected region between weak and saturating fields, where interesting behavior is observed. We provide the optimal field direction for a given field magnitude. We find a maximum possible Torque, which can be generated with relatively weak applied fields. This paper facilitates systems-level analysis, simulation, and real-time control of soft-Magnetic bodies.
Jangyoung Choi - One of the best experts on this subject based on the ideXlab platform.
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semi three dimensional analytical Torque calculation and experimental testing of an eddy current brake with permanent magnets
IEEE Transactions on Applied Superconductivity, 2018Co-Authors: Kyunghun Shin, Hanwook Cho, Hyungil Park, Jangyoung ChoiAbstract:This paper presents Torque analysis and testing of an eddy current brake with permanent magnets using semi-three-dimensional (3-D) analytical Magnetic field calculations. The Magnetic field solutions are obtained by considering the eddy current reaction using a 2-D Magnetic vector potential and 3-D case by a simple and effective axial dependence modeling. The Magnetic Torque is also determined from these solutions. A finite-element method (FEM) is employed to validate the analytical Magnetic calculations. The braking Torque measurement is experimentally verified to validate the analytical study. From the experimental study, we obtain analytical and 3-D FEM results of braking Torque with thermal behavior, and these are in good agreement with the experimental results.
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Parametric analysis and optimized Torque characteristics of a coaxial Magnetic gear based on the subdomain analytical model
AIP Advances, 2017Co-Authors: Kyunghun Shin, Hanwook Cho, Hyungil Park, Jangyoung ChoiAbstract:This paper presents the Torque calculation and parametric analysis of a coaxial Magnetic gear (CMG). We obtained analytical Magnetic field solutions produced by permanent magnets based on a Magnetic vector potential. Then, the analytical solutions for Magnetic Torque were obtained. All analytical results were extensively validated with nonlinear two-dimensional finite element analysis. Finally, using the derived analytical Magnetic Torque solutions, we carried out parametric analysis to determine the influence of the design parameters on the CMG’s behavior.
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Torque analysis and measurements of a permanent magnet type eddy current brake with a halbach magnet array based on analytical Magnetic field calculations
Journal of Applied Physics, 2014Co-Authors: Mingyu Park, Hyeonjae Shin, Jangyoung Choi, Seok-myeong JangAbstract:This paper presents the Torque analysis and measurements of a permanent magnet (PM) type eddy current brake (ECB) with a Halbach magnet array based on analytical Magnetic field calculations. On the basis of a Magnetic vector potential and using a two-dimensional (2D) polar coordinate system, the analytical solution for Magnetic flux density, including the eddy current reaction is evaluated. Based on these solutions, the Magnetic Torque is also determined analytically. A 2D finite element analysis is employed to validate the method used. Practical issues in the analytical study of the PM type ECBs, such as the maximum braking Torque, the required rotor speed, and the segment-dependent, are fully discussed. Finally, the braking Torque as a function of the rotor speed is measured to verify the results of the analytical study.
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analytical Magnetic Torque calculations and experimental testing of radial flux permanent magnet type eddy current brakes
Journal of Applied Physics, 2012Co-Authors: Jangyoung Choi, Seok-myeong JangAbstract:This paper reports on analytical Magnetic Torque calculations and experimental tests of a radial flux permanent magnet (RFPM)-type eddy current brake (ECB). Analytical solutions for permanent magnet-generated Magnetic fields that consider the eddy current reaction are obtained by using a Magnetic vector potential and a two dimensional (2D) polar coordinate system. On the basis of these solutions, the analytical expressions for a Magnetic Torque are also derived. All analytical results are validated extensively by non-linear finite element calculations. In particular, Magnetic Torque measurements are obtained in tests to confirm the analyses. Finally, practical issues related to the analytical study of RFPM-type ECBs are fully discussed.