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91.
A high-grain multistage amplifier design technique is described. As countermeasures against FET drawbacks, the drain conductance dispersion was modeled and the DC parallel feedback was applied against process variations. Based on these and further feedback techniques, a limiting amplifier and a gain-controllable amplifier for satellite communication systems were designed and fabricated utilizing an 0.8 μm gate-length ion-implanted GaAs MESFET process. Moreover, their packages were developed considering stability conditions. A 45 dB 0.1-3.5 GHz limiting amplifier and a 22-38 dB 0.1-2.5 GHz gain-controllable amplifier were developed 相似文献
92.
A new state-of-polarisation (SOP) control scheme using two Faraday rotators is proposed. It features low optical insertion loss and quick response. Experiment shows that the receiver output is stable regardless of drastic SOP changes in the signal. 相似文献
93.
A photon-counting receiver using a GaInAs avalanche photodiode has been constructed. The receiver has a quantum efficiency greater than 1% in the spectral range from 800 to 1600 nm, where no practical photomultipliers are available. The real-time recording of single photon incidence is also achieved with 20 ns time resolution.<> 相似文献
94.
Chantamanee Poonjarernsilp Noriaki Sano Tawatchai Charinpanitkul Hiroki Mori Takeyuki Kikuchi Hajime Tamon 《Carbon》2011,(14):4920-4927
Single-walled carbon nanohorns (SWCNHs) hybridized with palladium (Pd) nanoparticles were synthesized by a single-step gas-injected arc-in-water method (GI-AIW) with a Pd wire inserted inside the anode hole. In the arc zone, carbon and Pd were vaporized simultaneously, leading to the formation of hybrid material of SWCNHs and Pd nanoparticles due to effective quenching. Based on TEM and CO chemisorption analyses, Pd nanoparticles were found to be embedded inside SWCNH aggregates. The size of Pd nanoparticles, determined by X-ray diffraction, was in the range of 3–6 nm when Pd wires with diameters of 0.1 and 0.3 mm were used. Using a Pd wire with a diameter larger than 0.5 mm results in larger Pd nanoparticles which tend to be exposed to the outer surface of the hybrid material. According to thermogravimetric analyses, the weight fraction of Pd nanoparticles is increased by increasing the Pd wire diameter although the yield of Pd nanoparticles decreased. SWCNHs hybridized with dispersed Pd nanoparticles, synthesized with 0.1 mm Pd wire, exhibited strong anti-oxidation resistance with a highly graphitic structure. 相似文献
95.
Takachio N. Iwashita K. Hata S. Onodera K. Katsura K. Kikuchi H. 《Microwave Theory and Techniques》1990,38(12):1900-1905
A balanced receiver for multigigabit-per-second coherent optical transmission systems is described. A balanced optical receiver with a frequency bandwidth of 23 GHz is achieved by connecting an InGaAs twin-p-i-n photodiode to a 0.5-30.0 GHz GaAs monolithic distributed amplifier fabricated with a soldier bump flip-chip interconnection technique. An experiment which demonstrated that this receiver has the potential for use in 10-Gb/s optical CPFSK (continuous-phase frequency shift keying) heterodyne detection systems was conducted 相似文献
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99.
T Komuro S Miwa XF Zhang T Minowa T Enoki S Kobayashi Y Okamoto H Ninomiya T Sawamura K Kikuta Y Iwamuro H Furutani H Hasegawa Y Uemura H Kikuchi T Masaki 《Canadian Metallurgical Quarterly》1997,30(4):504-509
The alpha-amylase of Streptomyces sp. IMD 2679 was subject to catabolite repression. Four different growth rates were achieved when the organism was grown at 40 degrees C and 55 degrees C in the presence and absence of cobalt, with an inverse relationship between alpha-amylase production and growth rate. Highest alpha-amylase yields (520 units/ml) were obtained at the lowest growth rate (0.062 h-1), at 40 degrees C in the absence of cobalt, while at the highest growth rate (0.35 h-1), at 55 degrees C in the presence of cobalt, alpha-amylase production was decreased to 150 units/ml. As growth rate increased, the rate of specific utilisation of the carbon source maltose also increased, from 46 to 123 micrograms maltose (mg biomass)-1 h-1. The pattern and levels of alpha-glucosidase (the enzyme degrading maltose) detected intracellularly in each case, indicate that growth rate effectively controls the rate of feeding of glucose to the cell, and thus catabolite repression. 相似文献
100.
Topology optimization for reduction of vibration caused by magnetic harmonic excitation 总被引:1,自引:0,他引:1
We apply the homogenization design method (HDM) to reduce the vibration level of a structure excited by magnetic harmonic force. We do this by obtaining the optimal material distribution of the structure to minimize the frequency response. We first use the Maxwell stress method to compute the magnetic force and then apply HDM for the optimization. Results show that the HDM can be used to minimize the frequency response. This method can also be applied to other rotary electrical devices such as motors and generators. 相似文献