International Journal of Applied Electromagnetics and Mechanics - Volume 45, issue 1-4

Authors: Woo, Taeseong | Nagase, Masae | Ohsaki, Hiroyuki | Sekino, Masaki

Article Type: Research Article

Abstract: MRI systems have technical challenges in interference with metals and high cost because of the use of strong magnetic field. Ultralow-field MRI is an emerging technique enabling measurement of samples containing metals due to low resonant frequencies, as well as saving cost due to its simplified coil system. We developed a compact SQUID system for ultralow-field MRI equipped with a magnetic shield box of 1 × 1 × 1.5 m. Oscillating magnetic fields were applied to …the pick-up coil of SQUID from an external coil with a magnetic flux density equivalent to magnetic resonance signals from water of 10 ml. The SQUID successfully detected external magnetic fields of 3.08 × 10^{-12} T. Show more

Keywords: Superconducting quantum interference device, SQUID, MRI, magnetic resonance, biomagnetics

DOI: 10.3233/JAE-141905

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 45, no. 1-4, pp. 771-778, 2014

Authors: Iwasaki, Norihisa | Kitamura, Masashi | Enomoto, Yuji

Article Type: Research Article

Abstract: This paper reports a utility of the design method that conducts thermo-magnetic coupling analysis by using a heat equivalent circuit and describes evaluation results of relationship between losses and temperature rise based on magnetic properties. We manufactured and tested prototype motors that were designed with thermo-magnetic coupling analysis and found that reduction of copper loss become of particular importance in order to reduce temperature rise, and total losses of motors.

Keywords: Permanent magnet motor, efficiency, temperature rise, magnetic properties, losses

DOI: 10.3233/JAE-141906

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 45, no. 1-4, pp. 779-786, 2014

Authors: Tsuchimi, Daisuke | Sasaki, Kana | Okuyama, Takeshi | Tanaka, Mami

Article Type: Research Article

Abstract: A palpation is a useful method to detect cancer and to evaluate skin or under skin conditions. However, the palpation is a skillful method. Doctor's mental and physical conditions affect diagnoses by the palpation. Additionally, it is hard to share the feeling of palpation with other people because palpation is subjective skill. Therefore, the development of the sensor that can measure the skin and under skin condition of the body like softness as a doctor's palpation …is demanded. In this paper, we focus on a haptic perception mechanism of human for evaluating the softness. Six objects are made to conduct sensory tests. The silicone rubber part of the objects has two kinds of thickness and three kinds of Young's modulus. Relationships between physical properties of evaluated objects and the softness that human feel in active touch are investigated. After that, to control the contact condition between objects and finger, a passive touch evaluation system is fabricated. Using the system, relationships between the stiffness of the objects and evaluated haptic softness are investigated under passive touch condition. Show more

Keywords: Tactile, haptic, softness, stiffness, magnitude estimation

DOI: 10.3233/JAE-141907

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 45, no. 1-4, pp. 787-792, 2014

Authors: Faktorová, Dagmar | Isteníková, Katarína

Article Type: Research Article

Abstract: The paper presents some optimization approaches to the electromagnetic wave focusing in heterogeneous biological tissue model. The model of human arm was used for investigation. The possibility of focusing of electromagnetic wave optimisation is strongly connected with investigation of electromagnetic wave propagation through complicated heterogeneous biological structure. Firstly we concentrated on the influence of particular structures thickness on scattering parameters value which gives us information about transmission and reflection of electromagnetic wave …on interfaces of structures which differ by dielectric parameters. The next simulation showed the influence of water bolus placed on the arm model surface on values of SAR and consequently the possibility to avoid the overheating of upper region of arm model in the process of microwave hyperthermia. The next step connected with possible optimisation of electromagnetic wave focusing showed the influence of metamaterial structure placed in the front of microwave patch antenna used in role of microwave hyperthermia applicator on the electromagnetic wave focusing. The simulations were done for various numbers of metamaterial structures and various distances from arm model. Finally we simulated the focusing accuracy in the case when the combination of water bolus with metamaterial structure was used. Show more

Keywords: Human arm model, metamaterial structure, microwave applicator, specific absorption rate, water bolus

DOI: 10.3233/JAE-141908

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 45, no. 1-4, pp. 793-800, 2014

Authors: Faktorová, Dagmar

Article Type: Research Article

Abstract: The paper deals with some methods for relative permittivity of dielectric materials measurement and with the relevant techniques. In addition to current methods of measurement evaluation on vector network analyser our new approach gives also information about possibility of the use of classical methods for evaluation of application at vector network analyser as a faster source of basis for computations. In the paper also an attention to a situation is paid when it is problematical to …determine the unknown permittivity of solid material by usual methods. Show more

Keywords: Microwave frequencies, relative permittivity, scattering parameters

DOI: 10.3233/JAE-141909

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 45, no. 1-4, pp. 801-807, 2014

Authors: Peng, Tao | Moulin, Johan | Alves, Francisco | Bihan, Yann Le

Article Type: Research Article

Abstract: Multilayered magneto-impedance microsensors (Finemet/Copper/Finemet) were elaborated by microfabrication process using bi-layers lift-off method. A post-annealing step was carried out at 300°C for 1h under magnetic field, which led to induce a longitudinal or transversal anisotropy in the magnetic films. A method based on a double amplitude demodulation was proposed for the sensitivity characterization corresponding to the AC magnetic field measurement capability. According to these alternating magnetic field characterizations, the sensitivity, the linearity …and the bandwidth of the microsensor were obtained. The highest sensitivity is around 4200 Ω/T and the measurable sensor bandwidth reaches up to 300 kHz. The sensor presented no hysteresis since a DC bias field larger than anisotropy field is applied. Show more

Keywords: Magneto-impedance micro sensor, AC measurement, alternating field

DOI: 10.3233/JAE-141910

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 45, no. 1-4, pp. 809-816, 2014

Authors: Zhu, Haitao | Demachi, Kazuyuki | Wu, Wenjing | Sekino, Masaki

Article Type: Research Article

Abstract: Magnetic susceptibility is the inherent property of materials. Magnetic resonance imaging as a kind of non-invasive testing technique may measure the magnetic field distortion induced by the imaging object and consequently calculate its magnetic susceptibility distribution. Conventionally, magnetic susceptibility mapping is performed in three-dimensional mode with the requirement of multi-slice scanning. In the condition of long objects that have uniform distribution along one direction, two-dimensional phase image of the cross section might …be enough to estimate the susceptibility. In this study, we adjust susceptibility mapping algorithm into a two-dimensional mode and evaluate the possibility of using a single-slice image to estimate the magnetic susceptibility. Simulation was performed to validate the algorithm in both ideal and noise-imposed conditions. MRI experiment was performed by using copper, graphite and iron oxide at different concentrations. The results suggest that it is possible to measure the susceptibility of a long object by a two-dimensional image. Show more

Keywords: Magnetic resonance imaging, susceptibility mapping, phase image

DOI: 10.3233/JAE-141911

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 45, no. 1-4, pp. 817-823, 2014

Authors: Zhao, Ruzhen | Zhao, Shuang | Luo, Yun

Article Type: Research Article

Abstract: NOTES (natural orifice translumenal endoscopic surgery) allows for exceedingly minimally invasive surgery but has high requirement for dexterity, force capabilities and safety of tools. Researchers have proposed some flexible instrument used in surgeries. However, little work has considered the safety problem of the instrument to human tissues due to the absence of controllable flexibility and insufficient force capabilities. This paper presents a design of a flexible and stiffness changeable mechanism which can serve as a tunnel …for NOTES tools. Furthermore, the flexible and the stiffness changeable properties are evaluated by FEM analysis. Show more

Keywords: Flexible, stiffness changeable, compliant mechanism, NOTES

DOI: 10.3233/JAE-141912

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 45, no. 1-4, pp. 825-831, 2014

Authors: Wang, Minghui | Zhou, Ying | Wu, Yue | Gan, Yun | Zhao, Ruzhen | Luo, Yun

Article Type: Research Article

Abstract: Soft tissue injuries remain as problems in the application of clamping devices due to overload. Clamping devices with constant force or pressure is desired to solve the problem. This paper proposed a C-shaped component using superelastic shape memory alloy (SMA) sheet to realize constant force clamping. Optimization design of the component was carried out with computational simulation. Numerical results show that approximately constant force can be obtained by varying the initial shape, the end width and …the end thickness of the SMA sheet. Show more

Keywords: Shape memory alloy, constant-force, superelasticity

DOI: 10.3233/JAE-141913

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 45, no. 1-4, pp. 833-837, 2014

Authors: Zhou, Ying | Wang, Minghui | Zhao, Ruzhen | Luo, Yun

Article Type: Research Article

Abstract: Constant-stress phenomenon is an unique property of shape memory alloys (SMAs) and could be widely used in designing surgical devices. It is easily obtained by stretching a SMA wire, but for SMA strips little work has been done. This paper presents a design of constant-force elements by bending superelastic SMA strips. The numerical results show its feasibility for practical use.

Keywords: Constant-force, shape memory alloys, parameter optimization

DOI: 10.3233/JAE-141914

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 45, no. 1-4, pp. 839-843, 2014