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31.
A wide-band high-gain AGC amplifier stabilizing the output dc level against a broad gain variation is proposed and monolithically integrated using high-speed 1-μm Si-bipolar IC technology. The fabricated IC exhibits a maximum gain of 39 dB, gain dynamic range of 44 dB, bandwidth of 800 MHz, and output dc-level fluctuation of 8 mV, and realizes wide dynamic range and direct dc-coupling of the multistage AGC amplifier. Also, in order to examine the feasibility of the fabricated IC, a 1.5-μm-wavelength optical transmission experiment was carried out using DFB-LD and InGaAs-APD. Measured minimum received optical power for an error rate of 10-9is -40 dBm at 560 Mbit/s and -38 dBm at 1.12 Gbit/s. Optical dynamic range of 30 dB is also achieved by using the fabricated IC and APD. 相似文献
32.
Terufumi Okumura Yasuhiro Kinoshita Hiroaki Uchiyama Hiroaki Imai 《Materials Chemistry and Physics》2008,111(2-3):486-490
Photoluminescence depending on nitrogen concentration was investigated using anatase-type TiO2 prepared by the calcination of a mixture of titanyl sulfate hydrate and urea. The substitutional ratio (x) of nitrogen in TiO2 was successfully varied from 0.004 to 0.022 by changing the molar ratio of the mixture. The absorbance at 380–560 nm due to the formation of mid-gap states was proportional to the substitutional ratio of nitrogen controlled by the preparation conditions. In contrast, the fluorescent intensity at 382 nm originating from the band-to-band transition monotonically decreased with an increase in the substitutional ratio with an expansion of the anatase lattice. On the other hand, the maximum intensity of photoluminescence at 560 nm excited at 350 nm, which could be associated with the transition from the conduction band to the mid-gap states, was observed at x = 0.01. The optimal substitutional ratio for the emission was almost agreed with that for the photocatalytic decomposition of methylene blue and acetaldehyde under visible-light illumination. The photoluminescence was fundamentally determined by the balance between photoexcitation originating from a sufficient number of mid-gap states and deactivation of excited electrons and holes due to lattice distortion or defective states induced with the nitrogen doping. 相似文献
33.
Harumi Yokokawa Natsuko Sakai Teruhisa Horita Katsuhiko Yamaji Yueping Xiong Takanori Otake Hiroo Yugami Tatsuya Kawada Junichiro Mizusaki 《Journal of Phase Equilibria》2001,22(3):331-338
Phase diagram calculations that were made previously for the ZrO2-MO m/2 (m = 2, 3, 4) systems and for the ZrO2-YO1.5-MO m/2 (M = transition metals) systems have been extended to the ZrO2-YO1.5-CeO2(-CeO1.5) system to make an attempt to explain (1) thermogravimetric (TG) results as a function of oxygen potential, (2) electronic conductivity as a function of oxygen potential, and (3) a miscibility gap observed in air. The interaction parameters for the CeO2-CeO1.5-YO1.5 system were obtained from the reported oxygen nonstoichiometry in CeO2−x and rate earth doped ceria, (Ce,RE)O2−δ . The interaction parameters for the ZrO2-CeO2 subsystem were obtained so as to reproduce the observed miscibility gap at 1273 K. Those thermodynamic properties can reproduce consistently the experimental behaviors of the electronic conductivity and the TG results in the (Zr1−x Ce x )0.8Y0.2O1.9 solid solutions; these indicate the enhancement of reduction of CeO2. 相似文献
34.
Sinterability of various high-purity magnesium oxide powders 总被引:3,自引:0,他引:3
Kiyoshi Itatani Masayuki Nomura Akira Kishioka Makio Kinoshita 《Journal of Materials Science》1986,21(4):1429-1435
The sinterability of high-purity MgO powders with different production histories was investigated to make clear the relationship between the powder characterization, the densification processes, and the changes in microstructure both with increasing temperature at a rate of 10° C min–1 and at a fixed temperature of 1450° C for 5 h. The densification behaviour and the changes in microstructure of these compressed bodies were affected chiefly by their original surface activity and degree of agglomeration, depending on the production histories: (i) the ultra-fine and well-dispersed powder prepared by the vapour-phase oxidation process showed that densification proceeded with an appreciable grain growth with few closed pores remaining; (ii) powder derived from the sea-water magnesia process showed that the densification behaviour was affected by the species of magnesium salt, i.e. basic magnesium carbonate or magnesium hydroxide, used as a precursor; however, whichever magnesium salt was used, its sintered compact showed similar closed porosities and grain-size distributions; (iii) powder derived from the spark-discharge process contained skeletons of the original Mg(OH)2 particles; however, the densification proceeded gradually with slow grain growth, reflecting the fact that the powder has a moderate surface area (36 m2 g–1). The sintered compact from (iii) had a small closed porosity and the smallest grain-size distribution among the compacts used in this investigation. 相似文献
35.
The effect of voluntary exercise on maximal oxygen uptake (VO2 max) was studied in young female Fischer 344 rats. After 10 weeks of wheel-running training, the absolute VO2 max and VO2 max relative to body mass increased without a decline in body mass. The running speed eliciting VO2 max, heart and soleus muscle mass, and succinate dehydrogenase (SDH) activity in the soleus muscle also increased. These results suggest that voluntary exercise is an effective means of increasing the aerobic exercise capacity of young female Fischer 344 rats. 相似文献
36.
A simple common-collector full-monolithic preamplifier is developed using an advanced 3 ?m Si-bipolar IC technology SICOS. The amplifier characteristics are a 650 MHz bandwidth and a 5.2 pA/?(Hz) equivalent input noise current at a 3 k? transimpedance. Measured optical sensitivity of a front end consisting of the amplifier and a Ge-APD is ?36.2 dBm for an error rate of 10?9 at a 560 Mbit/s bit rate and 1.3 ?m wavelength. 相似文献
37.
Jalal Salami Akio Shibata Daniel Meier Edgar Kochka Satoshi Yamanaka Preston Davis John Easoz Toru Abe Kazuo Kinoshita 《Solar Energy Materials & Solar Cells》1997,48(1-4)
This paper presents, for the first time, a low-cost, high-throughput manufacturing approach for fabricating n-base dendritic web silicon solar cells with selectively doped emitters and self-aligned aluminum contacts using rapid thermal processing (RTP) and screen printing. The self-aligned locally diffused emitter (SALDE) structure is p+ nn++ where aluminum is screen-printed on a boron-doped emitter and fired in a belt furnace to form a deep self-doped p+-layer and a self-aligned positive contact to the emitter according to the well-known aluminum-silicon (Al---Si) alloying process. The SALDE structure preserves the shallow emitter (20.2 μm) everywhere except directly beneath the emitter contact. There the junction depth is greater than 5 μm, as desired, in order to shield carriers in the bulk silicon from that part of the silicon surface covered by metal where the recombination rate is high. This structure is realized by using n-base (rather than p-base) substrates and by utilizing screen-printed aluminum (rather than silver) emitter contacts. Prototype dendritic web silicon (web) cells (25 cm2 area) with efficiencies up to 13.2% have been produced. 相似文献
38.
Ueda S Kinoshita M Tanaka F Tsuboi M Shimizu S Oohata N Hino M Yamada M Isogai Y Hashimoto S 《Journal of Bioscience and Bioengineering》2011,112(4):409-414
Micafungin (FK463) is a widely used treatment for life-threatening, deep-seated fungal infections. It is an echinocandin-like lipopeptide derived from the chemical modification of deacylated FR901379, a type of lipopeptide antibiotic produced by Coleophoma empetri F-11899. The palmitoyl moiety of FR901379 is deacylated by FR901379 acylase produced by Streptomyces sp. no. 6907. In this study, our goal was to generate an improved strain of Streptomyces sp. no. 6907 capable of hyperproducing the FR901379-acylase enzyme. To accomplish this goal, modified strains of Streptomyces sp. no. 6907 were generated using UV-irradiation mutagenesis, and strain selection was performed using an agar-plate screening method to efficiently select an acylase-hyperproducing strain. Three marker indices were shown to correlate with elevated acylase production: decreased candidacidal activity of FR901379, decreased proteolytic activity on skim milk, and phenotypic characteristics. Cloning and subsequent sequencing of the acylase gene from the hyperproducing mutant revealed no mutations in either the acylase structural gene or the 5'-flanking region required for gene expression. The growth medium was also modified to maximize acylase production. We successfully increased acylase activity approximately 65-fold, compared with the original growth conditions (wild strain cultured in the original unmodified medium). To minimize formation of excess foam during the fermentation process, we optimized the parameters of agitation speed, as calculated from the discharge flow rate. Using our improved strain and the optimized medium and growth conditions, we have developed an improved and highly reproducible method for stable large-scale production of FR901379-acylase. 相似文献
39.
H. Serizawa K. Nakajima Y. Arai T. Yamashita K. Kuramoto H. Kinoshita S. Yamanaka M. Uno K. Kurosaki 《Progress in Nuclear Energy》2001,38(3-4):237-240
The phase relationship between ZrO2 and PuO2 was examined in a low PuO2 content region, from 3.1 to 11.2 mol% PuO2, at temperatures between 1273 K and 1473 K, by high temperature X-ray diffractometry. The measurements were carried out in air. At 1273 K, the samples in this composition range consisted of two phases, monoclinic and cubic. Another phase, tetragonal, was observed at 1373 K. The low temperature monoclinic phase disappeared at 1473 K. It was confirmed that the monoclinic phase disappears around 1463 K; the disappearance temperature does not depend on the composition of the sample. It was, thus, inferred that there should be a eutectoid line in the phase diagram. Though the eutectoid point is not clear, the PuO2 content at the point should be less than 3.1 mol%. 相似文献
40.
Yamauchi T. Kinoshita M. Amano T. Dosaka K. Arimoto K. Ozaki H. Yamada M. Yoshihara T. 《Solid-State Circuits, IEEE Journal of》2001,36(1):46-54
This paper proposes the virtual-socket architecture in order to reduce the design turn-around time (TAT) of the embedded DRAM. The required memory density and the function of the embedded DRAM are system dependent. In the conventional design, the DRAM control circuitry with the DRAM memory array is handled as a hardware macro, resulting in the increase in design TAT. On the other hand, our proposed architecture provides the DRAM control circuitry as a software macro to take advantage of the automated tools based on synchronous circuit design. With array-generator technology, this architecture can achieve high quality and quick turn-around time (QTAT) of flexible embedded DRAM that is almost the same as the CMOS ASIC. We applied this virtual-socket architecture to the development of the 61-Mb synchronous DRAM core using 0.18-μm design rule and confirmed the high-speed operation, 166 MHz at CAS latency of two, and 180 MHz at that of three. The experimental results show that our proposed architecture can be applied to the development of the high-performance embedded DRAM with design QTAT 相似文献