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This paper describes continuous millimeter-wave and terahertz (THz)-wave applications, where telecom-based photonics technologies are efficiently employed to enhance their performance. First, 300-GHz-band wireless communications are described toward real-time error-free transmissions at 50 Gbit/s and beyond. Next, a novel approach to increase a phase measurement sensitivity in THz frequency-domain spectroscopy systems is explained, and a similar technique is successfully applied to the visualization of electric-field radiation and propagation. Finally, as a futuristic study, the manipulation of THz waves with a concept of photonic crystals and its possible applications to platforms in THz integrated systems are presented. [ABSTRACT FROM AUTHOR]

We developed microenergy harvesters using impact-induced oscillation to scavenge electrical power from low frequency (<200 Hz) and random environmental vibrations. The microharvesters comprised a (K,Na)NbO3/Si composite cantilever and a cylindrical cavity to guide a metal ball to perpendicularly strike the cantilever. Through ball impact, oscillation of the cantilever was induced, generating electrical power at ambient vibration frequencies from 20 to 150 Hz. The contact time of ball impact was identified as a key parameter for power enhancement and was effectively tuned by adjusting the impact position on the triangular cantilever. The experimental output power when the impact position was at the base of the cantilever was 34.6 nW. This value is tenfold higher than that from conventional devices in which the ball strikes the tip of the cantilever. [2015-0063] [ABSTRACT FROM AUTHOR]

The first MgZr co-doped AlN-based vibrational energy harvester (VEH) is presented. (MgZr)AlN, which is a new class of doped AlN, provides high piezoelectricity and cost advantage. Using 13%-(MgZr)-doped AlN for micromachined VEHs, maximum output power of 1.3 μW was achieved with a Q-factor of 400 when resonant frequency, vibration acceleration, load resistance were 792 Hz, 8 m/s2, and 1.1 MΩ, respectively. Normalized power density was 8.1 kW.g?2.m?3. This was one of the highest values among the currently available piezoelectric VEHs. [ABSTRACT FROM AUTHOR]

In this paper, a surface-acoustic-wave (SAW)-driven atomizer with micropumps was developed. The micropumps consisted of an epoxy-based reservoir with an exhaust slot and a pair of interdigital transducers (IDTs). The liquid supply from the reservoir was controlled by SAW bursts from the IDTs. A microsurge tank was fabricated into the exhaust slot to stabilize the atomization. The transferred liquid was atomized by a pair of arc-shaped IDTs (AS-IDTs). The AS-IDT was optimally designed using optical vibration observations to focus the SAW energy into a single point and enabled high directional atomization. In the operational test of the micropump with water, a transfer rate of 0.24 pl per single burst was confirmed, where the burst signal is operated at 24.1 MHz with a 50% duty cycle, 40-ms period, and 70~V\mathrm {p-p} amplitude. In the water atomization test, we succeeded in ejecting a narrow mist spray from the substrate using a burst signal operating at 23.8 MHz with a 20% duty cycle, 1-ms period, and 50~V\mathrm {p-p} amplitude. The width of the ejected mist spray was 0.7 mm in the vicinity of the substrate, and was maintained at <1 mm within the ejection height of 8 mm. [2014-0146] [ABSTRACT FROM AUTHOR]

A vibration-driven micropower generator with a high-Q mechanical resonator efficiently works under single-frequency vibration. However, the associated narrow operation frequency bandwidth tightly limits the power output under commonly observed wideband ambient vibrations. In this paper, we present a power-generation scheme in which the motion of an internal mass element is actively controlled. The control is such that the vibrating environment is forced to do the maximum possible work to the power generator. Electret-based energy conversion was analyzed as a means to realize the scheme, drawing on evidence from an experiment. We further analyzed the active control in general terms to reveal potential performance that is substantially above the conventional designs [ABSTRACT FROM AUTHOR]

We confirmed the structural properties of trilayered epitaxial films with AML [Fe/Co]n and Au spacer on Au electrode by RHEED and TEM. A considerably large ΔRA (2.61 mΩμm2) resistance area product was observed in all metallic current perpendicular-to-plane giant magneto-resistance (CPP-GMR) spin-valve elements by using alternate monatomic epitaxial [Fe/Co]n ferromagnetic layer with IrMn layer on the top. The estimated spin scattering asymmetry coefficient β and interface asymmetry coefficient γ was 0.81 and 0.43 ±0.05, respectively. This value of β is higher than that of Fe5oCo5o/Cu laminated with Cu spacer or Heusler alloy which is largest value ever reported at room temperature. [ABSTRACT FROM AUTHOR]

An HTS magnet for a Superconducting Maglev, consisting of four persistent current HTS coils, was developed. The HTS coils are installed in a cryostat, and cooled to approximately 15 K by conduction cooling, using two sets of two-stage GM type pulse tube cryocoolers. The HTS magnet is operated in a persistent current mode at a rated magneto-motive force of 750 kA. The running tests were executed on the Yamanashi Maglev Test Line, with a top speed of 553 km/h achieved on December 2, 2005. The test result demonstrated that the HTS coils generated no excessive vibration or heat load. [ABSTRACT FROM AUTHOR]

This paper describes the outline of a development project for the HTS magnet for the superconducting Maglev, which commenced in 1999. A very small current decay rate of 0.44%/day was achieved in 2003, using a prototype HTS coil, and a second HTS magnet, consisting of four persistent current HTS coils, was produced in 2005 for vehicle running tests. The second HTS magnet was operated in a persistent current mode at a rated magneto-motive force of 750 kA, and a top speed of 553 km/h was attained on the Yamanashi Maglev Test Line on December 2, 2005. [ABSTRACT FROM AUTHOR]

We developed an HTS coil for maglev applications. The magnet consists of four persistent current HTS coils and is operated at a rated temperature of 20 K and a rated magnetomotive force of 750 kA for each coil. This paper describes the fabrication and test results of each persistent current HTS coil. The HTS coil consists of 12 single-pancake coils wound with four parallel Ag-sheathed Bi2223 wires and a persistent current switch (PCS) made of YBCO thin films. The coil is conductively cooled by a cryocooler to approximately 20 K. Persistent current operating tests for four HTS coils at 750 kA were carried out and current decay rates of 0.37–0.68 %/day were obtained. Mechanical vibration tests up to ± 15 g (±150 m/s²) were carried out to investigate the mechanical properties of the HTS coils. Temperature increasing tests up to 25 K, which is 5 K higher than the rated operating temperature and higher magnetomotive force operating tests up to 800 kA were carried out to investigate the thermal stability of the coils and check the mechanical strength of the coils. [ABSTRACT FROM AUTHOR]

An HTS magnet for maglev application has been developed. The magnet consists of four persistent-current HTS coils, and is operated at a rated temperature of 20 K and a rated magnetomotive force of 750 kA for each coil. This paper describes the structure and performance test results of the HTS magnet. The four HTS coils are installed in a cryostat and conductively cooled by two sets of two-stage GM type pulse tube cryocoolers below 20 K. Detachable current leads, which are composed of connectors and ultrasonic motors, are adopted to reduce the heat leakage to the 1st stage cold head of the cryocoolers. The HTS coils are simultaneously charged up to the rated magnetomotive force. Persistent current operating tests were carried out and the current decay rates of 0.4–0.7%/day were attained. Also, in order to evaluate the mechanical capability of the magnet, vibration tests were conducted and permissible vibration responses were obtained. [ABSTRACT FROM AUTHOR]

Annealing processes in MgB2 films deposited on yttria-stabilized zirconia (YSZ)buffered Hastelloy substrates were studied by transmission electron microscopy. The MgB2 films with Mg-rich compositions were fabricated at room temperature using a pulsed laser deposition (PLD) method. The as-deposited films do not exhibit clear superconducting transitions, and have inhomogeneous microstructures composed of amorphous regions and a small amount of crystalline MgB2 and MgO with several tens of inn in size. Various sizes of voids are also incorporated within the amorphous regions. After the annealing at 600 or 680°C, the films exhibit clear superconducting transitions. The amorphous regions crystallize into fine grains of MgB2 or MgO 5-50 nm in size. The voids remain in the annealed films and their sizes depend on the annealing condition. Magnesium-and oxygen-rich layers are formed near the MgB2/YSZ interface and the film surface. It is suggested that the finer grains of MgB2 and MgO obtained by the lower-temperature annealing give a larger critical current density under a high magnetic field. [ABSTRACT FROM AUTHOR]

An high temperature superconducting (HTS) magnet, consisting of an HTS coil, a persistent current switch, a GM type two-stage pulse tube cryocooler, and YBCO current leads was developed. Detachable current leads were adopted to reduce heat leakage during persistent current operation. The HTS coil was cooled to approximately 10 K and persistent current mode operas lion tests were carried out at various currents up to 532 A, which is the rated current. Current decay at each persistent current mode operation was investigated by measuring the magnetic field at the center of the coil. The current decay rate at the 532 A operation was found to be approximately 0.44%/day. [ABSTRACT FROM AUTHOR]

We fabricated a persistent current HTS magnet wound with conductors composed of four Ag-sheathed Bi2223 wires and an insulated stainless-steel tape. The HTS magnet is composed of. 12 racetrack formed single-pancake coils and impregnated with epoxy resin. The magnet is the same size as a magnet for a Maglev train. The stored energy of the magnet is 034 MJ and the central magnetic field is 1.3 T at the rated current operation of 532 A. Cooling the magnet to less than 20 K, I-V characteristics in persistent current operations and AC losses in charging and discharging the magnet were investigated. [ABSTRACT FROM AUTHOR]

We developed a persistent current high temperature superconducting (HTS) magnet for Maglev train. The HTS magnet mainly consists of an HTS coil, a persistent current switch (PCS), a GM type two-stage pulse tube cryocooler. A PCS is one of the most important components to maintain persistent current operation. A YBCO thin film was adopted for a PCS conductor because it has a high resistivity over a critical temperature and a high critical current density at lower temperatures. Persistent current mode operation tests were successfully carried out with the PCS. The current decay rate at the rated current operation of 532 A was 0.44%/day which was investigated by measuring the magnetic field at the center of the coil. [ABSTRACT FROM AUTHOR]

This paper describes design concept, fabrication, and experimental results of a Persistent-Current Switch (PC S) for High Temperature superconducting (HTS) magnets. Recently large-size HTS magnets have been fabricated with Ag-sheathed Bi2223 wires. Even in the case of HTS magnets, persistent-current mode has the advantage of maintaining a steady magnetic field for long periods. A PCS for an HTS magnet is a key component to realize persistent-current mode. A PCS for an HTS magnet must work at the same operating temperature as an HTS coil, and electrical resistivity for a PCS conductor should be sufficiently large to reduce the energy dissipation during charge and to shorten the switching time. To satisfy these requirements, a YBCO thin film is adopted for a PCS conductor. The PCS is used in a vacuum and conductively cooled by a cryocooler at around 20 K when the switch is "on". To change the PCS from "on" to "of", the temperature of the PCS is increased to around 100 K by electrical heaters. A new design concept of a PCS for an HTS magnet is introduced. And the test results of rated current operation, switching operation and persistent-current operation are shown. [ABSTRACT FROM AUTHOR]

This paper presents and discusses experimental results for mechanical performance of HTS coils with epoxy impregnation. Though mechanical characteristics of Ag-sheathed Bi2223 tape conductors have been investigated by various research organizations, there are few reports on those for HTS coils. Experiments on static hoop stress as well as experiments on repetitive hoop stress were performed. The critical static hoop stress obtained at 4.2 K was found to be 1.4∼1.6 times higher than the critical tensile stress of the conductor. The coil did not deteriorate after io4 times loading of 70% of the critical hoop stress. [ABSTRACT FROM AUTHOR]

Introduces an interface system for a digital television (DTV) control utilizing speech recognition. Features of the DTV user interface with speech recognition; Information on the automatic speech recognition system.

Presents information on a study which examined the Iron-Chromium (Fe-Cr) powdered alloys synthesized via mechanical alloying through magnetization and ...Fe Mossbauer spectroscopy. Characteristics of Fe-Cr alloy systems; Preparation of the Fe-Cr powdered alloys; Results and conclusion.

This paper describes a low heat leak current-lead system for a high temperature superconducting magnet which is refrigerated by conduction cooling and operated in a persistent-current mode. Under the condition that the current lead is cooled by conduction without gas cooling, we investigated the current-lead structure with which the heat load to the cryocooler is sufficiently low. The current lead consists of two parts. One of them spans the temperature interval between room temperature and around 70 K. The other spans the temperature interval between around 70 K and the lower end temperature. The former is made of copper alloy and the latter is made of HTS superconductor. To decrease the heat leak to a thermal anchor in the 70 K region, a detachable joint is installed in the copper alloy part. The driving mechanism for the joint is set in the room temperature region. An ultrasonic rotation motor, which works in the vacuum and the magnetic field, is adopted for the driving mechanism. We designed and constructed a detachable current lead of 600 A class, and obtained a test result that the heat leak to the thermal anchor is sufficiently low. [ABSTRACT FROM AUTHOR]