Abstract: An antenna for a transponder comprises a magnetic core composed of layered amorphous metallic thin plates or composite plates of soft magnetic flakes and a synthetic resin, and a coil wound on the magnetic core. A transponder comprises two antennas set forth above, and a spiral antenna.

Abstract: A body detecting element is buried in the ground together with a body such as a metal body and includes a magnetic member acting as a magnetic core, an antenna coil wound around the magnetic member and a capacitor connected to both the ends of the antenna coil for forming a resonance circuit together with the antenna coil. The antenna coil is mounted on the body integrally therewith through an electromagnetic shield member with the outer peripheral surface thereof confronting the outer surface of the body. A body detecting element includes an RFID circuit connected to the antenna coil and mounted on a body integrally therewith such that the outer peripheral surface of the antenna coil confronts the outer surface of the body through an electromagnetic shield member. Even if the body detecting element is mounted on the body such as the metal pipe integrally therewith, it can accurately detect the body because a resonant frequency and the Q value of the coil are not changed.

Abstract: A body detecting element is buried in the ground together with a body such as a metal body and includes a magnetic member acting as a magnetic core, an antenna coil wound around the magnetic member and a capacitor connected to both the ends of the antenna coil for forming a resonance circuit together with the antenna coil. The antenna coil is mounted on the body integrally therewith through an electromagnetic shield member with the outer peripheral surface thereof confronting the outer surface of the body. A body detecting element includes an RFID circuit connected to the antenna coil and mounted on a body integrally therewith such that the outer peripheral surface of the antenna coil confronts the outer surface of the body through an electromagnetic shield member. Even if the body detecting element is mounted on the body such as the metal pipe integrally therewith, it can accurately detect the body because a resonant frequency and the Q value of the coil are not changed.

Abstract: An antenna for a transponder comprises a magnetic core composed of layered amorphous metallic thin plates or composite plates of soft magnetic flakes and a synthetic resin, and a coil wound on the magnetic core. A transponder comprises two antennas set forth above, and a spiral antenna.

Abstract: A method and a device for determining the amount of ink or similar liquid existing in a container are disclosed. A resonance circuit is arranged on the container storing the liquid. A voltage having a preselected frequency is applied to a drive coil located outside of the container to thereby induce a voltage having a preselected frequency in the resonance circuit. The voltage induced in the resonance circuit, in turn, induces a voltage having a preselected frequency in a sense coil also located outside of the container. The amount of liquid in the container is determined in terms of the voltage induced in the sense coil.

Abstract: A burglar detection apparatus has a tag 11 that includes a resonance circuit. The tag is preferably contained with an object 15 whose theft is desired to be detected. The tagged object may be placed in a drawer 14 which is contained in a box 13. A tag detection sensor 16 is installed in the box and detects whether the tag 11 is present in the drawer 14. Also, a drawer sensor 17 detects whether the drawer is opened. Based on respective detection outputs of the tag detection sensor 16 and the drawer sensor 17, a control circuit 19 controls an alarm 18. Advantageously, the apparatus can be installed in a comparatively small space, does not malfunction even if subjected to large amounts of electrical noise, and reliably detects the presence or absence of a tag even if the tag is located near a metal object.

Abstract: A theftproof tag which is effective regardless of the material of the article to which it is attached. There is neither a change in resonance of a resonance circuit nor a decrease in the Q value due to the material of the surface of a theft monitored article, thereby decreasing errors in the operation of a theft monitor. The theftproof tag has a resonance circuit resonating to an electric wave at a specified frequency transmitted from a transmitting antenna, and having a coil unit and a capacitor electrically connected to both ends of the coil unit. The coil unit has a magnetic core member made of a composite material composed of a powder or flakes of a soft magnetic metal, and a plastic, and a winding wound around the periphery of the magnetic core member and connected to the capacitor, a portion of the magnetic core member facing the attaching surface of the article.

Abstract: An anti-theft tag for attachment to a theft-monitored article including a resonance circuit which resonates radio waves of a predetermined frequency transmitted from an antenna, and a shielding coil having at least two terminals. The shielding coil is disposed between the resonance circuit and the article when the anti-theft tag is attached to the article, and the at least two terminals are short-circuited.

Abstract: An anti-theft tag which when attached to an article containing a conductive surface properly transmits a signal to a control device to generate an alarm if the article has been taken without permission. The anti-theft tag includes a resonance circuit and a soft magnetic material disposed between an attaching face of the article and the resonance circuit. The soft magnetic material allows the anti-theft tag to provide a resonance frequency which is independent of the material the anti-theft tag is attached to. The soft magnetic material may be composed of, for example, any one of an amorphous alloy, PERMALLOY, electromagnetic soft iron, silicon steel sheet, sendust alloy, Fe--Al alloy, and soft magnetic ferrite. The soft magnetic material may also be a composite material of soft magnetic material flakes and a plastic.

Abstract: Graphite cast iron is diecast at a solid-liquid coexisting state with a mold having a gate opened at an area of not more than 1/10 of a pressurized area of a plunger tip.

Abstract: When a semi-solidified metal composition is formed in a forging die assembly, it is formed under conditions satisfying particular mass fraction solid and flowing rate in the die and then held under a given pressure until the metal composition is completely solidified.

Abstract: A powdery raw material for manufacturing an anode of a fuel cell comprises a powder of a nickel-base alloy consisting essentially of 0.5-10 percent by weight aluminum, and the balance of nickel and inevitable impurities, and having a mean grain size of 3-20 microns. The nickel-base alloy powder may contain 0.01-1.0 percent by weight oxygen, and/or may have an apparent density of 0.5-3.5 g/cm.sup.3, and a specific surface area of at least 0.12 m.sup.2 /g. Advantageously, the nickel-base alloy powder is formed by means of water-atomization under a condition that the water injection pressure is 400 Kg/cm.sup.2, and the specific water quantity is 0.02-0.2 m.sup.3 /Kg, the thus manufactured anodes exhibit initial anode characteristics as excellent as those of conventional anodes, and possess such excellent high-temperature creep strength and sintering resistance, thereby exhibiting excellent anode characteristics over a long period of time.