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1.
Ten-user truly asynchronous gigabit OCDMA transmission experiment with a 511-chip SSFBG en/decoder 总被引:8,自引:0,他引:8
Hamanaka T. Xu Wang Naoya Wada Nishiki A. Kitayama K. 《Lightwave Technology, Journal of》2006,24(1):95-102
A ten-user truly asynchronous gigabit coherent-optical-code-division-multiple-access (OCDMA) transmission was experimentally demonstrated without using any timing coordination. The enabling technologies are a record-length 511-chip superstructured-fiber-Bragg-grating (SSFBG) en/decoder and a supercontinuum (SC)-based optical-thresholding technique to significantly suppress the signal interference beat noise as well as the multiple-access-interference (MAI) noise. 相似文献
2.
Yoichi Shindo Naoya Katagiri Toichi Ebisuno Masatoshi Hasegawa Miyuki Mitsuda 《大分子材料与工程》1996,240(1):231-239
Poly (vinyl alcohol) with pendent styrylpyridinium groups (SbQ) is insolubilized by photoirradiation. An association takes place in SbQ groups. The association of polymer chains becomes marked with increasing the number of SbQ groups. Mainly intermolecular crosslinks were formed. Transparent and homogeneous macrogels consisting of several intermolecular crosslinks are obtained. The proportion of the free water to the bound water in PVA-SbQ gels was 3.3?2.9 despite of the large change in conversion of photodimerization of SbQ groups, x=0.27?0.58. The water uptake after swelling of the gels in water increased 6–27 times compared to the original weight at pH=7. The higher the degree of photocrosslinking, the lower was the degree of swelling. The water diffusion coefficients, D, were (2.2?5.8) × 10?5 cm2 S?1 for a 88% saponified PVA with 1 . 3 mol% SbQ groups. The volume of the gel increased discontinuously about 10-fold for the 99% saponified PVA with 0 . 096 mol% SbQ and 51% water (49% acetone). The acetone concentration at the transition decreased with increasing the degree of saponification of the PVA. 相似文献
3.
An investigation was undertaken on the application of dilute chitosan solutions gelled by tyrosinase‐catalyzed reaction with 3,4‐dihydroxyphenethylamine (dopamine). The tyrosinase‐catalyzed reaction with dopamine conferred water‐resistant adhesive properties to the semidilute chitosan solutions. The viscosity of the chitosan solutions increased highly by the tyrosinase‐catalyzed reaction and the subsequent reactions between o‐quinone compounds and chitosan. These highly viscous, gel‐like modified chitosan materials were allowed to spread onto the surfaces of the glass slides, which were tightly lapped together and held them in water. Tensile shear adhesive strength of over 400 kPa was observed for the modified chitosan samples. The increase in the amino group concentration of the chitosan solutions and the molecular mass of the chitosan used effectively led to the increase in adhesive strength of the glass slides. In addition, in the case where the chitosan solution was gelled by the enzymatic reaction with dopamine in the presence of poly(ethylene glycol), adhesive strength sharply increased at shorter reaction times concomitantly with the increase in the viscosity of the chitosan solutions because the tyrosinase activity effectively was retained by poly(ethylene glycol). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1818–1827, 2007 相似文献
4.
A simple solid state technique for electrochemical micromachining of metal substrates using a metal ion conductor (Na-β″-Al2O3) was proposed. The fundamental solid electrochemical cell consists of a (anode) metal substrate (M = Ag, Cu, Zn, and Pb)/pyramidal Na-β″-Al2O3/Ag (cathode) system, where the contact diameter between M/Na-β″-Al2O3 was extremely small, on the order of a few micrometer. Under an applied electric field, the metal substrate was electrochemically oxidized to metal ions (Mn+) at the M/Na-β″-Al2O3 microcontact. These Mn+ ions migrated into the Na-β″-Al2O3. As a result of continuous electrolysis, the metal substrate was locally consumed at the microcontact, and thus solid state electrochemical micromachining was accomplished. As expected, the machining size or depth depended on the electrolysis conditions (current, operating time) and the apex configuration of pyramidal Na-β″-Al2O3. Moreover, the scanning of the Na-β″-Al2O3 pyramid during electrolysis produced a fine patterned metal substrate. In the present paper, solid state electrochemical micromachining was performed for several metal substrates, and its advantages and disadvantages vis-a-vis the conventional electrochemical micromachining method are discussed in detail. 相似文献
5.
Porous Ti compacts for biomedical applications are successfully fabricated in the porosity range from 5.0 to 37.1 vol% by controlling sintering conditions and Ti powder sizes. Young’s modulus and bending strength at the porosity of around 30 vol% are found to be similar to those of human cortical bone. 相似文献
6.
Hideyuki Azegami Liren Zhou Kimihiro Umemura Naoya Kondo 《Structural and Multidisciplinary Optimization》2013,48(1):115-125
This paper presents a numerical solution for shape optimization problems for link mechanisms, such as a piston-crank mechanism. The dynamic behavior of a link mechanism is described by a differential-algebraic equation (DAE) system consisting of motion equations for each single body and constraints of linkages and rigid motions. In a shape optimization problem, the objective function to maximize is constructed from the external work done by a given external force, which agrees with the kinetic energy of the link mechanism, for an assigned time interval, and the total volume of all the links forms the constraint function. The Fréchet derivatives of these cost functions with respect to the domain variation, which we call the shape derivatives of these cost functions, are evaluated theoretically. A scheme to solve the shape optimization problem is presented using the H 1 gradient method (the traction method) proposed by the authors as a reshaping algorithm, since it retains the smoothness of the boundary. A numerical example shows that reasonable shapes for each link such that mobility of the link mechanism is improved are obtained by this approach. 相似文献
7.
Hiroki Kikuchi Shigeki Hashimoto Shinichiro Tajiri Tsuneo Hayashi Yutaka Sugawara Michio Oka Yoshiyuki Akiyama Akira Nakamura Naoya Eguchi 《Journal of the Society for Information Display》2009,17(3):263-269
Abstract— A high‐pixel‐rate, high‐contrast (30,000:1) wide‐color‐gamut grating‐light‐valve laser projector is reported. A new optical engine enabling high‐frame‐rate (240 Hz) scan projection is employed. Panoramic wide‐angle‐scan projection with a 64:9 aspect ratio was also developed. Speckle noise is eliminated using a simple but highly efficient technique. The optical throughput efficiency of the grating‐light‐valve laser projector is reviewed. 相似文献
8.
Fumitaka Tsukihashi Toshiyuki Hatta Eiji Tawara 《Metallurgical and Materials Transactions B》1996,27(6):967-972
The deoxidation equilibrium of molten titanium and titanium-aluminum alloys saturated with solid CaO has been measured in the temperature range from 1823 to 2023 K. The equilibrium constant of reaction CaO (s)=Ca (mass pct in Ti,Ti-Al)+O (mass pct in Ti,Ti-Al) and the interaction parameter between calcium and oxygen were determined for Ti, TiAl, and TiAl3. The standard Gibbs energy of reaction for TiAl was obtained as follows: $$\Delta G^\circ = 279,000 - 103TJ/mol$$ The possibilities for the deoxidation of titanium and titanium-aluminum alloys by using calcium-based fluxes are discussed. 相似文献
9.
Kiyotaka Yamamura Naoya Igarashi 《International Journal of Circuit Theory and Applications》2004,32(1):47-55
In this letter, an efficient algorithm is proposed for finding all solutions of non‐linear (not piecewise‐linear) resistive circuits. This algorithm is based on interval analysis, the dual simplex method, and the contraction methods. By numerical examples, it is shown that the proposed algorithm could find all solutions of systems of 500–700 non‐linear circuit equations in acceptable computation time. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
10.