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61.
Kamei S. Inoue Y. Mizuno T. Shibata T. Kaneko A. Takahashi H. Iemura K. 《Electronics letters》2005,41(9):544-546
A silica-based 1.5%-/spl Delta/ 100 GHz-spacing 32-channel athermal arrayed-waveguide grating (AWG) with compact size and extremely low insertion loss is described. By reducing the fibre coupling loss and the excess loss in a silicone-filled groove, an insertion loss of 1.3 dB was achieved with this athermal AWG. 相似文献
62.
Yamada J. Miwa T. Koike H. Toyoshima H. Amanuma K. Kobayashi S. Tatsumi T. Maejima Y. Hada H. Mori H. Takahashi S. Takeuchi H. Kunio T. 《Solid-State Circuits, IEEE Journal of》2002,37(8):1073-1079
This paper describes a 128-kb FeRAM macro for smart-card microcontrollers. This macro, which was designed and fabricated using a 0.35-/spl mu/m three-metal CMOS and a Capacitor-on-Metal/Via-stacked-Plug (CMVP) process technology, is ideally suited for recent system LSIs such as smart-card microcontrollers. It has a flexible memory size ranging from 32 to 128 kb, a low consumption current of 0.3 mA, and endurance of more than 10/sup 8/ write/read cycles under a wide range of supply voltages, from 2.7 to 5.5 V. These characteristics, which are required of not only contact-type smart-card microcontrollers but also contactless-type ones, were achieved by using four newly developed circuit technologies: 1) a three-metal CMVP memory cell; 2) a voltage-regulating architecture; 3) a main/sub bitline and wordline structure; and 4) a dynamic-type offset sense amplifier. 相似文献
63.
Oda T. Kato T. Takahashi T. Shimizu K. 《Industry Applications, IEEE Transactions on》1998,34(2):268-272
Catalyst (copper-coated zeolite catalyst, i.e., Cu-ZSM-5) was used to enhance NOx removal plasma chemical reactions. Two kinds of hydrocarbons (2-propane-1-ol, 2-propanol) were added to the synthesized flue gas before the nonthermal plasma process, and their effects on NOx removal characteristics were investigated. Enhancement effects of NOx removal by the nonthermal plasma process with hydrocarbons as the additives were confirmed. Usually, the catalyst's working temperature is much higher than the room temperature. A catalytic reactor was installed after the plasma reactor. Catalytic effects on NOx removal characteristics disappeared when the synthesized flue gas temperature was increased (~250°C). When the synthesized flue gas temperature was at room temperature, about 90% NO x removal efficiency was realized with a combination of hydrocarbons, the catalytic reactor, and the pulsed discharge plasma 相似文献
64.
Seah Winston Khoon‐Guan Takahashi Yutaka Hasegawa Toshiharu 《Telecommunication Systems》1998,10(3-4):243-268
In this paper, we analyse the message waiting times in a local area network (LAN) that uses the demand‐priority access method.
This is a priority‐based round‐robin arbitration method where the central controller (the repeater) polls its connected ports
to determine which have transmission requests pending and the requests' priority classes. We model it as a 2‐priority M/G/1 queue with multiple server vacations and switchover time between service periods. The service discipline is nonpreemptive
and the length of the switchover time is dependent upon the priority class of the preceding message served as well as that
of the message to be served next. We provide an approximate analysis for the waiting times of both message classes and derive
expressions for the Laplace–Stieltjes transforms (LST) of the stationary distributions and the mean waiting times. We conclude
with numerical and simulation results to show the applicability and accuracy of the analytical model.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
65.
To obtain high power, well shaped picosecond pulses from gain-switched semiconductor lasers, the use of dynamic gain saturation characteristics of semiconductor laser amplifiers was investigated theoretically and experimentally. A configuration of a reflected-wave amplifier (RWA) with single-side external coupling is introduced for pulse shaping, which is found to be suitable for enhancing dynamic gain saturation. By a combination of a distributed feedback laser oscillator at 1.3 μm in wavelength and a reflected-wave amplifier of 400 μm cavity length with asymmetric facet reflectivities of 0.01% and 30%, single-mode optical pulses with almost no tailing, full width at half maximum of 15 ps, and peak power exceeding 50 mW were obtained without pulse broadening, despite the considerable tail structure of the incident pulse 相似文献
66.
Nakamura Masahiko Suzuki Yutaka Nagasawa Touru Sugihara Masami Takahashi Takashi 《IEEE transactions on bio-medical engineering》1982,(3):192-201
The homomorphic filtering method is described for the detection and quantitation of left-to-right shunts from radionuclide angiocardiography. First, the method is investigated theoreticatly and numerically using a realistic model with systemic recirculation. It is demonstrated that even in a noisy situation the shunt flow fraction can be relatively well estimated, if only the characteristics of the fiters used are suitable. Second, the method is applied to real data, i.e., the pulmonary time-activity curves from radionucUde anglocardiography. The presence or absence of a left-to-right shunt is determined using the ratio AT/MTT. The pulmonary-to-systemic flow ratios calculated from the areas of the two decomposed curves are compared with those from oximetry at cardiac catheterization. Good agreement between the Qp/Qs ratios calculated by oximetry and radionucUide angiocardiography is obtained. 相似文献
67.
Germanium-oxide glass optical fibre doped with antimony for transmission of the 2 to 3 ?m band has been prepared by the vapour-phase axial deposition (VAD) method. An attenuation loss of 13 dB/km at 2.05 ?m and 70 dB/km at 2.4 ?m has been achieved. 相似文献
68.
Kyoichi Osada Koretaro Takahashi Mutsuo Hatano 《Journal of the American Oil Chemists' Society》1990,67(12):921-922
The degree of glyceride syntheses by lipase TOYO (Chromobacterium viscosum) and lipase OF (Candida cylindracea) using individual free fatty acids C18∶1, C18∶2, C18∶3, C18∶4, C20∶4, C20∶5 and C22∶6 were compared. Lipase TOYO incorporated each of the fatty acids into glycerol at levels of greater than 89%. Lipase OF incorporated
most of the fatty acids at levels above 70% (docosahexaenoic acid incorporation was 63%). It was concluded that these two
lipases are feasible for producing glycerides from unsaturated fatty acids. 相似文献
69.
N. Takahashi 《臭氧:科学与工程》1990,12(1):1-17
Ozonation of several low molecular weight organic compounds under ultraviolet irradiation was studied. Nine compounds were identified as reaction products of the ozonation of phenol which was promoted by the simultaneous use of ozone and ultraviolet irradiation. In the case of several organic compounds having carbon numbers from one to six, the removal of total organic carbon (TOC) by this simultaneous use was higher than by either the ozone oxidation method or the ultraviolet irradiation method for all the compounds. 相似文献
70.
A sliding window mechanism is well known to be a convenient way to integrate cumulative acknowledgement and flow control functions in a simple manner. Hence, widely used reliable data-transfer protocols such as TCP-SACK and RLC utilize this sliding window mechanism in conjunction with a selective-repeat ARQ (automatic repeat request) function, namely, the selective-repeat sliding window protocol (SR-SWP). We demonstrate that SR-SWP yields a throughput restraint effect (TORE) in particular situations when packet losses occur. We propose an analytical performance model to represent the TORE in the case of heavy traffic. Using this model, we derive explicit forms of goodput and mean resequencing delay, which are fundamental qualities of service parameters. From numerical results, we demonstrate that the impact of TORE on the performance is not negligible for high packet-loss probabilities. Furthermore, we show that the SR-SWP model exhibits the lower goodput and the smaller mean resequencing delay than those obtained from the traditional SR-ARQ protocol model. 相似文献