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21.
A smooth impact rotation motor using a multi-layered torsional piezoelectric actuator 总被引:2,自引:0,他引:2
Morita T Yoshida R Okamoto Y Kurosawa MK Higuchi T 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1999,46(6):1439-1445
A smooth impact rotation motor was fabricated and successfully operated using a torsional piezo actuator. Yoshida et al. reported a linear type smooth impact motor in 1997. This linear motor demonstrated a high output force and a long stroke. A superior feature of the smooth impact drive is a high positioning resolution compared with an impact drive. The positioning resolution of SIDM (smooth impact drive mechanism) is equal to the piezo displacement. The reported positioning resolution of the linear type was 5 nm. Our rotation motor utilized a torsional actuator containing multi-layered piezoelectric material. The torsional actuator was cylindrical in shape with an outer diameter of 15 mm, an inner diameter of 10 mm, and a length of 11 mm. Torsional vibration performance was measured with a laser Doppler vibrometer. The obtained torsional displacement agreed with the calculated values and was sufficient to drive a rotor. The rotor was operated with a saw-shaped input voltage (180 V; 8 kHz). The revolution direction was reversible. The maximum revolution speed was 27 rpm, and the maximum output torque was 56 gfcm. In general, smooth-impact drives do not show high efficiency; however, the level of efficiency of our results (max., 0.045%) could be increased by improving the contact surface material. In addition, we are studying quantitative consideration, for example, about the optimum pre-load or frictional force. 相似文献
22.
Park JW Kurosawa S Aizawa H Han DS Yoshimoto M Nakamura C Miyake J Chang SM 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2003,50(2):193-195
We present conventional detection of 2,4-dinitrophenol (DNP) for using the competitive reaction between DNP and DNP-conjugated albumin onto DNP antibody immobilized quartz crystal microbalance (QCM). This QCM method allows detection of DNP concentration in the range of 0.01 to 100 ng/ml; linear correlation obtains DNP concentration from 1 to 100 ng/ml. 相似文献
23.
Bellare M. Boldyreva A. Kurosawa K. Staddon J. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2007,53(11):3927-3943
This paper proposes several new schemes which allow a sender to send encrypted messages to multiple recipients more efficiently (in terms of bandwidth and computation) than by using a standard encryption scheme. Most of the proposed schemes explore a new natural technique called randomness reuse. In order to analyze security of our constructions, we introduce a new notion of multirecipient encryption schemes (MRESs) and provide definitions of security for them. We finally show a way to avoid ad hoc analyses by providing a general test that can be applied to a standard encryption scheme to determine whether the associated randomness reusing MRES is secure. The results and applications cover both asymmetric and symmetric encryption. 相似文献
24.
Novel method for centre wavelength tuning of silica waveguide type Mach-Zehnder multi/demultiplexers
A novel method for tuning the centre wavelength of silica waveguide type Mach-Zehnder multi/demultiplexers (MUX/DEMUXs) has been devised. This tuning is achieved by irradiating a CO/sub 2/ laser beam onto either arm of the Mach-Zehnder interferometer. In a MUX/DEMUX for channel spacing of 20 nm, the centre wavelength is tuned about 3 nm and the results closely agree with the calculation.<> 相似文献
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The feasibility of a high speed zinc electrowinning cell using a Pt catalyzed hydrogen gas-diffusion electrode as an anode is investigated. This new type of zinc-winning cell is operated at a current density of 1.0 A cm–2, which is 20 times higher than usually employed in conventional methods. Current efficiency is 86% at 0.5 A cm–2 in an electrolyte containing 60 gl–1 Zn+270 gl–1 H2SO4, the zinc purity being at least 99.999%. The energy usage of the system is 1400 kWh and 380 m3 H2 gas per ton of zinc. 相似文献
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S Shimizu H Kurosawa M Nakano K Hashimoto K Suzuki M Yamagishi H Okuyama K Nomura 《Canadian Metallurgical Quarterly》1997,45(12):1961-1967
This study estimates the perioperative left ventricular function of VSD and TOF by using Pressure-Volume (PV) loop. The most characteristic hemodynamic change of VSD is a decreased volume load. Although ejection fraction significantly decreased after the operation, this change did not mean a deteriorated left ventricular contractility. Emax, which is an index of left ventricular contractility on PV loop, improved and pressure-volume area (PVA) which is correlated with 02 consumption of left ventricule was reduced. Mechanical efficiency of left ventricular energetic state did not significantly change. Left ventricular volume and ejection fraction in TOF slightly increased after the operation. Increased ejection fraction reflected a compensation to volume overload after surgery. Emax slightly decreased and PVA increased. Meanwhile mechanical efficiency increased after the operation indicating well preserved ventricular contractility. In particular, the shape of PV loop of both VSD and TOF eventually became usual square after operation due to recover of the isovolumic contraction and relaxation phase. These characteristics had better to be concerned for improvement of surgical techniques as in conotruncal repair, particularly in TOF in the setting of better quality of life with low atrial pressure. 相似文献
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Nawalage F. Cooray Katsumi Kushiya Atsushi Fujimaki Ichiro Sugiyama Tadayuki Miura Daisuke Okumura Masao Sato Mineo Ooshita Osamu Yamase 《Solar Energy Materials & Solar Cells》1997,49(1-4)
In this study, two deposition methods (i.e. MOCVD and sputtering methods) to prepare n-type ZnO window layers for CIGS-based thin-film solar cells are discussed. In order to make ZnO : Al transparent conductive oxide (TCO) films prepared by DC magnetron sputtering comparable to ZnO : B TCO prepared by MOCVD, a new ZnO sputtering process is proposed by introducing a multilayer structure. Using these films, CIGS thin-film solar cells with efficiencies of greater than 14% have been fabricated with an active area of 3.2 cm2. This structure was adapted to fabricate CIGS thin-film mini-modules with efficiencies around 11% having aperture area of 50 cm2. 相似文献