Improvements in the properties and output electric power of functional materials will expand their applications beyond sensors. Various functional materials, such as piezoelectrets made of silicone rubber, have been developed. In this study, a piezoelectret made of natural rubber is proposed. The proposed piezoelectret was fabricated by sandwiching and bonding natural rubber between fluoroethylenepropylene films and applying corona charging. A piezoelectret made of silicone rubber was fabricated in the same way and its performance was evaluated for comparison. The surface potential and piezoelectric stress constant for the piezoelectret made of natural rubber were higher than those for that made of silicone rubber. These results suggest that natural rubber is better than silicone rubber for fabricating rubberbased piezoelectrets.

抄録全体を表示

Although there are three surgical methods for laparo-endoscopic single site surgery depending on the forceps used, each has its own operational disadvantages, and there is no definitive surgical method. For this reason, it is often seen that laparo-endoscopic single site surgery technique is avoided by surgeons as a surgical technique, and the advantage of low patient burden is not utilized .Therefore, in this study, we focus on laparo-endoscopic single site surgery technique, which has a small patient burden but a large surgeon burden, and aim to overcome its disadvantages in terms of operation by developing new forceps to realize abdominal surgery that is beneficial to both the patient and the surgeon.

抄録全体を表示

This paper presents a new approach to error reduction for Vernier pattern angle sensor, which can become smaller and realize high solutions. The frequency components were investigated by performing discrete Fourier transform on the angle errors of a Vernier pattern angle sensor with respect to rotation speed. Three error equations were calculated from the obtained output voltage, which included noise, given as the error. The frequency components of the error distribution and the error equations were compared, and the frequency components given errors in case with 32(32X) and 31(31X) were discussed.

抄録全体を表示

This paper investigates the magnetization of magnetic pipe using two C-shaped permanent magnets. The novelty of the proposed monitoring method is that it requires only one magnetizing process. After this magnetizing process, low power consumption electronics of wireless sensor network with magnetic sensors are only required. From an experimental result, the validity of the FEM model using a sigmoid function is confirmed. The mechanism of magnetization process is explained by FEM analysis results. It was found that there are three types of magnetic flux distributions due to the thickness of the pipe. Choosing a suitable size for both the pipe and magnets allows the effective monitoring of pipe wall thickness.

抄録全体を表示

As the rotational speed of a motor increases for miniaturization, its stator core must have low iron losses. A magnetic composite core motor is introduced as a solution for a high-efficiency high-speed motor that incorporates a magnetic composite material with low iron loss for its stator. This magnetic composite material is composed of magnetic powder and a resin binder, with its saturation magnetic flux density and permeability determined by the volume fill ratio of the magnetic powder. In this study, ways to enhance the maximum volume fill ratio of magnetic composite materials to boost their effectiveness as motor cores were explored. Results show that the saturation flux density of the magnetic composite material improved from 0.65 to 0.75 T and its relative permeability (at 1 kA/m) increased from 19 to 21. As a result, the application domain of magnetic composite materials has expanded.

抄録全体を表示

The current implantable VADs target patients with a body surface area of 1. 4m²or above, generally addressing individuals aged around 12yearsand older among the Japanese population. In contrast, the pediatric VAD in the previous study was designed for implantation in children aged 1-6 years. Developing an implantable VAD that can be used from 1 to 12 years of age aims to reduce the number of VAD implantations, thereby alleviating the burden for patients. Therefore, the objective of this study is to develop a pediatric implantable VAD that can be used from1 to 12 years of age. To achieve this broader age range, it is necessary to increase the flow rate and outlet pressure without raising the upper limits of pump volume and impeller rotation speed. Considering these factors, this study is a fluid analysis for the development of a magnetically levitated centrifugal pump with a newly designed impeller and pump, with the aim of increasing the flow rate and outlet pressure suitable for children aged 1 to 12 years.

抄録全体を表示

In recent years, high speeds have been required to reduce the size of motors, but motors driven at high speeds are prone to increased losses. Among others, the generation of cogging torque due to spatial harmonics and the reduction in efficiency due to heat generation are considered. Therefore, this study proposes an interior-winding synchronous motor (IWSM) with a magnetic composite ring in the stator to suppress spatial harmonics. The efficiency of this IWSM is 7.3% higher than that of conventional motors.

抄録全体を表示

Pulmonary arterial hypertension (PAH) is a serious respiratory disease primarily caused by the narrowing of pulmonary arteries due to inflammation of the smooth muscle and endothelial cells.There is still no drastic treatment for PAH. Substances such as nitrite ions, which are expected to inhibit inflammation, are present in the active nitrogen species (RNS) contained in plasma-irradiated saline solution (PTS: plasma-treated saline solution), which is irradiated with atmospheric pressure low-temperature plasma (ALTP). Therefore, this study aimed to develop a novel treatment for PAH by suppressing inflammation through PTS administration in model rats, focusing on active nitrogen species (RNS), which are produced during PAH and have vasodilatory effects, and investigated their effects on suppressing inflammation and treating PAH symptoms. The evaluation included body weight measurement, ECG analysis to measure the specific ECG waveform that appears at the onset of PAH, and expression analysis of genes involved in the inflammatory process, such as IL-6 and STAT3.

抄録全体を表示

In patients with continuous flow ventricular assist devices, bleeding complications frequently occur due to the enzymatic degradation of von Willebrand Factor (vWF) large multimers. This degradation is caused by high shear stress from the device's high-speed rotating components. Although a double-cylinder-type shear load device has been proposed for the preliminary quantitative evaluation of vWF large multimers, it has not provided sufficient evaluation due to issues with the open-type shear portion and the contact-type mechanical bearings. These issues arise from air bubbles in the blood samples and unstable motor rotation. In this study, we propose a new shear loading device that features a closed-type shear portion and uses magnetic bearings to levitate the inner cylinder and rotate the outer cylinder. We experimentally evaluated that the levitation of the inner cylinder was controlled by two magnetic bearings (upper and lower), and the stability of the levitation.

抄録全体を表示

Metal discrimination is a technology in increasing demand for recycling and other purposes that can be performed by using different methods. The eddy current method utilizes changes in the impedance characteristics of the sensor coils due to eddy current in target. The amount of change on the conductivity and magnetic permeability of the target that can be used for metal discrimination. In this study, we combined the eddy current method with machine learning to discriminate composite metal . In experiments, we successfully discriminated between cupronickel plates and a cupronickel–nickel–cupronickel composite material. Our approach can potentially be applied in sensors to discriminate metals within metals.

抄録全体を表示

Electromagnetic induction heating has been extensively studied. For fusion bonding of carbon-fiber-reinforced plastics and carbon-fiber-reinforced thermal plastics, heat transfer analysis is considered necessary to ensure heating uniformity. In this study, the electrical resistivity characteristics of carbon fiber cloth are experimentally investigated, and the electrical resistivity of carbon fiber cloth is modeled. The experimental results show that the electrical resistivity tends to decrease with increasing thread density. A model is developed to quantitatively examine the electrical resistivity of carbon fiber cloth.

抄録全体を表示

This study presents a novel approach to static load measurement that addresses a limitation inherent to single piezoelectric elements. We propose a sensor design utilizing a piezoelectric vibrator constructed by bonding two identical piezoelectric elements; one element is excited at its resonant frequency, while the other generates voltage by responding to the induced vibration. When a load is applied to the sensor body, the external force significantly alters the mechanical impedance of the vibrator, causing a rapid drop in sensor voltage. However, the sensor voltage saturates very quickly with even a small load, resulting in an extremely limited measurable load range. To address this drawback, we developed a load application method using an elastic body with a load-dependent shape. This elastic body mediates the load application, causing the mechanical impedance of the vibrator to change gradually in response to increasing load. This approach allows for control over sensor voltage characteristics, including both measurement range and linearity.

抄録全体を表示

Because of sensory neuropathy in the sole of the diabetic foot, it is difficult to notice injuries such as being hit by a nail or a pebble. Co-occurrence of wounds leads to foot ulcers and gangrene, and when the sole becomes gangrenous, the lower limb must be amputated. To avoid the occurrence of foot ulcers, one solution is to support sensory functions by covering the entire sole with electrical skin that has tactile functions. This study proposes a self-powered stretchable electrical skin (eee-skin) with tactile function. The results of contact detection experiments confirmed that the output voltage increases with increasing elongation rate, and a maximum output voltage of approximately 0.6 V was obtained at an elongation rate of 10% and a contact of approximately 0.5 N.

抄録全体を表示

This study examines the influence of alterations in the dimensional parameters, particularly the pole pitch (τ), on the features of segmented switched reluctance linear synchronous motors (SSRLSM). A validated analytical model of the SSRLSM is employed in the investigation of the impact of adjusting the pole pitch on the static characteristics of the motor. The primary focus lies in the evaluation of the consequences of modifying the pole pitch (τ) on the static characteristics of the SSRLSM. The pole pitch is modified at ratios of 1.0, 0.75, 0.5, and 0.25. Through the analysis, valuable insights are gained regarding how changes in the pole pitch (τ) can impact the overall static characteristics and operational efficiency of the SSRLSM.

抄録全体を表示

Magnetostriction is a typical magneto-mechanical phenomenon observed in magnetic materials, which is accompanied by hysteresis. In this paper, we attempt to modify the Classical Jiles-Atherton model (CJA model), which is a typical differential hysteresis model of a magnetization process, into a hysteresis model of magnetostriction curve. At first, we compared the hysteresis of the magnetization curves and the magnetostriction curves and clarified the differences. Then, we proposed a method to incorporate the "proceed" characteristics of the magnetostriction hysteresis curves into the CJA model. Finally, to verify the correctness of the modifications, the proposed model was checked to see if it could represent the experimental data of nickel measured under several uniaxial stresses. The verification results show that the magnetostriction curves of nickel can be represented with high accuracy using the proposed Jiles-Atherton type differential hysteresis model.

抄録全体を表示

In this study, changes in levitation characteristics were investigated by modifying the combination of high-temperature superconductors with groove and step geometry in addition to the magnetic circuits. The levitation characteristics were verified by analyzing the restoring force and vibration characteristics of the fabricated superconducting magnetic bearings in each direction. The experimental results confirmed that the restoring force characteristics and vibration damping were improved by appropriately arranging the groove and step geometry in relation to the magnetic flux gathering area. The experiments showed the usefulness of modifying the geometry and the magnetic circuits.

抄録全体を表示

Currently, permanent magnet synchronous motors (PMSMs) are commonly used for EV traction motors. However, there are some problems in the cost of permanent magnets, high speed rotation, and the stable supply of rare earth resources. On the other hand, switched reluctance motors (SRMs) have simple, robust and inexpensive structure. However, SRMs have problems such as a large torque ripple, noise and vibration. In addition, SRMs are driven by a 3-phase asymmetric inverter, and the inverter cost is higher than a 3-phase inverter. Therefore, in order to solve these problems, we have proposed a 12/10 SRM that has a hex connection and is driven by a 9-switch inverter. In this paper, 12/10 SRMs with hex connection and conventional star connection are designed, and the characteristics and radial force of the stator under pulse drive using a 6-phase inverter are compared. Finally, the difference between the hex connection and star connection is discussed.

抄録全体を表示

The authors have proposed a new method of passively suppressing torque ripple in AC motors using magnetic periodic reversing springs (MPRS). In this method, the torque ripple is suppressed by optimally designing the order, phase, and amplitude of the torque fluctuation of the MPRS based on magnetic field analysis and mounting it concentrically to the output shaft of the AC motor. However, the results mentioned above were only a simplified evaluation based on static torque characteristics. In this paper, we solve the time-dependent field and evaluate the practicality of the MPRS in more detail. First, the effect of eddy current losses in the MPRS on motor efficiency is determined by three-dimensional finite element analysis. Furthermore, the possibility that radial forces acting between the rotors of the MPRS induce motor electromagnetic oscillations is evaluated.

抄録全体を表示

This paper describes a DC electric field measurement circuit which enables power saving in a field mill. An electric field measurement circuit of a conventional field mill detects an electric charge on induction electrodes generated by an applied electric field as a current. This current flows instantly and ends, so the rotary shutter must rotate at high speed. Therefore, the conventional field mill consumes a large amount of power. The authors introduce a method to reduce the power consumption by detecting an electric potential of the induction electrodes with a high impedance input circuit for a long time. One of the problems in realizing this method must be a reduction of leakage current in printed circuit boards and various devices. In this study, the leakage current experimentally was verified using test models based on this method. And the experimentally results were also evaluated by steady current analyses using the finite element method.

抄録全体を表示

Abdominal Aortic Aneurysm (AAA) is a disease that progresses without symptoms and has a high mortality rate. Abdominal ultrasonography is the initial diagnosis of choice for this disease, and the presence or absence of an aneurysm is determined by the length of the inter-pericardial distance of the vessels depicted on the ultrasound image. On the other hand, because ultrasound images are unclear, the accuracy of vessel diameter measurement depends on the skill of the reader. Therefore, for early detection and accurate diagnosis of diseases, a system that automatically analyzes blood vessels from images and supports reading and diagnosis is required for ultrasound systems. Therefore, in this study, we developed and evaluated a system that has functions for detecting vascular regions and measuring the distance between vascular adventitia using an image segmentation model and a model learned with YOLOv10 on ultrasound images of the abdominal aorta.

抄録全体を表示

High-frequency isolation transformers are used to suppress high-frequency patient leakage current flowing in the insulated parts of medical devices. In this study, we assumed that the high-frequency isolation transformer would be placed in an aluminum case for actual case and researched whether the coil-to-coil capacitance was small enough to suppress the high-frequency patient leakage current below the regulated value. The coil-to-coil capacitance was analyzed and measured by changing the items laid in the isolation transformer, the presence of PTFE wrapped around the isolation transformer, and the number of ferrite cores used in the isolation transformer. The results of the analysis in the electromagnetic field simulation showed that the smallest capacitance was 5.040pF when two ferrite cores were used, PTFE tape was wound, and a 1.0mm PTFE plate was laid. The actual measurement also showed a minimum of 3.9807 pF in this case.

抄録全体を表示

We propose a multimodal CNN that reconstructs conductivity distribution images by combining features from multiple sets of potential data. A comparison with a single modal CNN, which reconstructs images from a single set of potential data, was performed. The reconstructed images were evaluated for the size and position of foreign objects. While the multimodal CNN did not show significant improvement in terms of size accuracy compared to the single modal CNN, it demonstrated superior performance in position estimation. Additionally, we examined reconstructions of polygonal objects and objects with rotation. The multimodal CNN exhibited higher resolution in capturing object shapes and rotations compared to the single modal CNN. Future work will focus on applying this method to the non-destructive inspection of building materials, beyond simulations.

抄録全体を表示

Microwave mammography is being developed as a new examination method for breast cancer. Evaluation of device performance is necessary in the development process of medical devices. However, experiments using the human body or animals tend to be avoided because of the ethical issues involved. An electromagnetic phantom that simulates the permittivity and conductivity of a living body is useful for this purpose. In this study, we aimed to develop a fat-equivalent phantom at 1-15 GHz, which is expected to be used in microwave mammography, and which accounts for a high percentage of the breast. As a result, the relative permittivity and conductivity agreed with the target values with an average error rate of 6.75% and 18.2%, respectively. In addition, the usable temperature range of the prototype phantom was also investigated.

抄録全体を表示

When surgery is performed without cardiac arrest, an artificial heart-lung machine is used to replace the functions of the heart and lungs. One of these functions is vent suction. One of its functions is to suction blood in the cardiac cavity to prevent myocardial overextension. However, if the tip of the suction part sticks to the myocardium, it cannot fulfill this function and excessive negative pressure is generated. In addition, it is not easy to measure negative pressure directly due to problems such as infection. The principle of suction is the restorative force generated by the pump head squeezing the circuit in a roller pump. When the negative pressure in the suction circuit increases, the force that holds the inner diameter of the circuit inside acts to weaken the restoring force, and the circuit does not return to its original diameter. By measuring the decrease in the restoring force, we attempt to detect excessive negative pressure in the vent suction circuit.

抄録全体を表示

In this paper, torque characteristics of an induction motor with a hybrid rotor made of copper and non-oriented electrical steel sheet will be examined under two-phase excitation. At first the magnetic flux density and eddy current distribution of the induction motor with the hybrid rotor were clarified analytically with electromagnetic field analysis. Next, the induction motor with the hybrid rotor was fabricated by fitting the copper ring into the laminated non-oriented electrical steel sheet, and the torque characteristics of the induction motor with the hybrid rotor and solid rotor were measured. It was found that the torque of the hybrid rotor was about twice greater than that of the solid rotor.

抄録全体を表示

Oil dampers are widely used to absorb vibration or shock energy in transportation equipment and industrial machinery. However, deterioration of the sealing material due to temperature fluctuations or aging can lead to oil leakage, resulting in reduced functionality. Therefore, alternative oilless dampers, such as eddy current dampers have been expected. However, their performance has not yet reached that of conventional oil dampers. This paper aims to develop an eddy current damper with a damping coefficient of more than 200 N·s/m. A doublepipe structure composed of copper and iron was employed for the stator, and the movable component consisted of optimally designed permanent magnets and iron cores. As a result of optimization using magnetic field analysis, a damping coefficient of 207 N·s/m was estimated. Finally, a prototype was fabricated, and experimental results confirmed a damping coefficient of more than 200 N·s/m.

抄録全体を表示