K. Seki

A new meander type contactless power transmission system-active excitation with a characteristics of coil shape

We propose a contactless power transmission system using a new meander type coil. Effectiveness for stabilizing the amount of the transmitted power against a load displacement and suppressing electromagnetic noise emission is the features of meander type coils. Maximum power is transmitted when the pitch of the transmitter coil corresponds to the receiver shape. An Active Excitation System was realized using circuit in which the relative position between transmitter and receiver coils are always assured. Furthermore the system result is an optimal distribution of flux. Therefore, the receiver position is cleared and transmitter-pitch is set up optimally.

A new temperature telemeter with temperature-sensitive magnetic cores

A new telemeter has been made by using temperature -sensitive magnetic cores. The system needs only units such as a temperature-frequency converter using the temperature-sensitive magnetic cores and a power amplifier since it converts core temperature directly into high frequency. It seems to be useful in the field of temperature management because it can be used to measure temperature in water and in the sea.

Temperature-sensitive magnetic thin-film for micro sensor

A temperature-sensitive magnetic thin-film (TMT) is made by sputtering Mn-Zn ferrite. Temperature-sensitive magnetic cores and thick-films have already been fabricated, however a magnetic thin-film with temperature dependence has not been shown yet. The authors developed a TMT by a new method with RF sputtering of a TMT utilizing a low Curie temperature Mn-Zn ferrite core as a target. The TMT with quick thermal response can be used as a micro temperature sensor, a thermomagnetic transducer or a photomagnetic device.

Use of a temperature-sensitive ferrite for temperature/humidity measurements

A temperature-sensitive ferrite (TSF) is a multi-ability sensor, which adds the functions of a thermistor and a switching diode to the temperature-sensitive magnetic core. The TSF has a humidity dependence which causes the resistance to decrease with a rise in humidity. Magnetic reluctance is temperature-dependent and is independent of humidity. Techniques for converting temperature and humidity into frequencies are discussed. >

Photo-magnetic semiconductor using pyromagnetic effect

A photomagnetic semiconductor (PMS), composed of a thick film magnetic semiconductor and a radiant flux absorbent, is described. The PMS with a thickness of 55 mu m is made of a ferrite powder and a ruthenium compound and its surface is painted with a radiant flux absorbent. The PMS is a pyromagnetic film utilizing the temperature dependence of the magnetic reluctance. When visible rays are radiated to the PMS, the radiant flux absorbent captures the light energy and transfers thermal energy to the magnetic semiconductor, which causes the reluctance change of the PMS. Therefore, the PMS acts as a nonwinding photomagnetic transducer. The PMS is suitable for use as a photosensor, a photorelay, a photochopper, or an exposure meter. >

Composition and heating efficiency of magnetic wood by induction heating

The purpose of this paper is to propose a new combination type heating board with improved heating efficiency and heating characteristics. This article covers experimental results of measuring surface temperature, heating function, heating efficiency and leakage magnetic field intensity of magnetic combination type heating board by induction heating. The results showed that the heating board with magnetic coating layers and the exciting coil/magnetic binder layer had the highest heating characteristics and heating efficiency. The heating board we propose can be used in house building materials and medical equipment that require a warm and smooth surface.

Pressure/photo sensor utilizing polymer magnetic composite

A polymer magnetic composite (PMC) is a flexible thick film and is composed of a ferrite powder with variable possible Curie temperatures, polymer and solvent. It is found that high and low Curie temperature PMCs can be used for pressure and photosensors, respectively. The set up combined with the PMC and a pressure element acts as a pressure sensor. The device, painted with a radiant flux absorbent on the surface of the PMC, responds to the visible rays. The pressure and light signals are read out by a Hall element in noncontact with the PMC. >

Investigation of multi-ability temperature-sensitive magnetic semiconductor with non linear negative resistance

The temperature-sensitive magnetic semiconductor is one kind of ferrite which is called a temperature-sensitive magnetic core whose magnetic and electrical properties both exhibit a marked temperature dependence. The temperature-sensitive magnetic semiconductor can be regarded as a multi-ability magnetic semiconductor device, having the effect of adding a thermistor and a bidirectional diode to the temperature-sensitive magnetic core.

Indicating thermometers using a temperature-sensitive magnetic core

New indicating thermometers have been made by us with a temperature-sensitive magnetic core. Our instruments need no converter such as other electric thermometers use since they make use of the temperature-sensitive magnetic cores reluctance. The instruments can be utilized as panel, portable, and monitoring thermometers.

A new environmental monitor sensor utilizing thick-film magnetic semiconductor

The preparation of a thick-film magnetic semiconductor (TMS) using ferrite powder and a ruthenium compound is described, and the application of its properties to a multipurpose sensor is considered. The TMS was sintered at a relatively low temperature and showed ferromagnetic and semiconducting properties which were dependent on the temperature, humidity, and gas concentration. The TMS is a versatile device: a temperature-sensitive magnetic core, a thermistor, and a varistor can be added to ordinary resistance and capacity elements. Considering these characteristics, the TMS can be used as a temperature/humidity/gas sensor for a modulated environmental monitor. A novel temperature-signal readout method due to the magnetic head is also introduced for the TMS pattern sensor. >