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151.
Hiromasa Tawarayama Etsuko Ishikawa Kenji Yamanaka Katsuhisa Itoh Keiko Okada Hiroshi Aoki Hiroaki Yanagita Yoshihiko Matsuoka Hisayoshi Toratani 《Journal of the American Ceramic Society》2000,83(4):792-796
Praseodymium-doped glasses were prepared in the Ga-Na-S (GNS) system and their optical properties were studied. A single-mode fiber with an attenuation loss of 1.2 dB/m at a wavelength of 1.31 μm was fabricated using an extrusion method, and the amplification characteristics were measured in the bidirectional pumping configuration. We demonstrated a gain coefficient of 0.81 dB/mW at a wavelength of 1.34 μm, which is the highest we have ever reported, and achieved a net gain of 32 dB for a pump power of 90 mW. Highly efficient optical amplification at a wavelength of 1.3 μm was demonstrated in the praseodymium-doped GNS fiber. 相似文献
152.
153.
Akazawa K. Makikawa M. Kawamura J. Aoki H. 《IEEE transactions on bio-medical engineering》1989,36(7):746-753
For developing functional neuromuscular stimulation (FNS) orthoses, percutaneous implants made of sintered hydroxyapatite (HAp) and a microprocessor-based portable stimulator were devised, and related basic studies were carried out. First, a button-shaped HAp was percutaneously implanted up to 23 months in the skin of dogs, and 30 months in human subjects. The HAp was closely contacted with the skin tissue. Then, button-shaped HAp electrical connectors were percutaneously implanted in the skin of rabbits. Sufficient contractions of the calf muscle were elicited by electrical stimuli delivered to intramuscular electrodes through the connector. These results indicated that the HAp electrical connector could be clinically utilized as an implantable skin interface for FNS. The microprocessor-based stimulator capable of processing control command signals and delivering 16-channels of electrical stimuli was developed. Usefulness of the stimulator was demonstrated by applying it to flexor and extensor muscles of the thumb in a C5 quadriplegic patient. 相似文献
154.
A metal/insulator/semiconductor (MIS) structure of Ga0.47In0.53As has been prepared by applying an excimer laser photo-CVD process to depositing an SiNx insulating layer. It is found that interface state densities can be remarkably reduced by in situ photochemical etching with CC14 or CH3Br gases prior to SiNx deposition. A minimum value of the U-shape profile of the interface state density as low as 5 × 1011 cm-2eV-1is attained. 相似文献
155.
H. Aoki Y. Asada T. Hatano K. Ogawa A. Yanase M. Koiwa 《Journal of Low Temperature Physics》1990,81(1-2):19-29
Studies of the dHvA effect have been made on NbO single crystals grown by a zone melting techniques and 13 separate frequency branches ranging from 5.2×106 G to 1.2×108G have been observed. To understand the origin of the dHvA frequencies, we have made a self-consistent band structure calculation. Most experimental frequencies are found to be assigned to the extremal orbits on the calculated Fermi surfaces. There is good qualitative agreement between experiment and calculation, but some quantitative discrepancies still exist. We also report some physical properties, i.e., electrical resistivity, superconducting transition temperature, and electronic specific heat, of this high-quality NbO crystal. 相似文献
156.
157.
One‐way delay variation (OWDV) has become increasingly of interest to researchers as a way to evaluate network state and service quality, especially for real‐time and streaming services such as voice‐over‐Internet‐protocol (VoIP) and video. Many schemes for OWDV measurement require clock synchronization through the global‐positioning system (GPS) or network time protocol. In clock‐synchronized approaches, the accuracy of OWDV measurement depends on the accuracy of the clock synchronization. GPS provides highly accurate clock synchronization. However, the deployment of GPS on legacy network equipment might be slow and costly. This paper proposes a method for measuring OWDV that dispenses with clock synchronization. The clock synchronization problem is mainly caused by clock skew. The proposed approach is based on the measurement of inter‐packet delay and accumulated OWDV. This paper shows the performance of the proposed scheme via simulations and through experiments in a VoIP network. The presented simulation and measurement results indicate that clock skew can be efficiently measured and removed and that OWDV can be measured without requiring clock synchronization. 相似文献
158.
Masashi Imanaka Shigeo Tomita Suguru Kanda Mitsuteru Fujieda Kimikazu Sasa Jens Olaf Pepke Pedersen Hiroshi Kudo 《Journal of aerosol science》2010,41(5):468-474
To investigate the contribution of ions to gas nucleation, we have performed experiments on the formation of water droplets in H2O/N2 and H2O/Ar gas mixtures by irradiation with a 20 MeV proton beam and by positive corona discharge. The size of the formed nanoparticles was measured using a differential mobility analyzer equipped with a Faraday cup electrometer. Using the proton beam, droplets around 10 nm in diameter were observed for both positively and negatively charged particles, but none were found when the corona discharge was used. This implies the importance of the presence of both positive and negative ions for the formation of nanosize droplets, which attract each other by Coulomb interactions, enhancing the collision frequency and leading to the formation of the 10 nm droplets. 相似文献
159.
Seiji Kumagai Hirotaka Ishizawa Yuta Aoki Yasuhiro Toida 《Chemical engineering journal (Lausanne, Switzerland : 1996)》2010,156(2):270-277
A molded carbon/silica composite with high micro- and mesoporosity, as well as a high bulk density, was fabricated by activating a disk-molded precursor made from carbonized rice husk (RH) and beet sugar (BS) at 875 °C in CO2. The pore structure of the RH- and BS-based carbon/silica composite (RBC) was analysed in relation to the bulk density. An activation time of 2.0 h provided the largest BET specific surface area (1027 m2/g) and total pore volume (0.68 cm3/g) and a low bulk density (0.54 g/cm3). An RBC that was first activated for 1 h was immersed again in BS syrup and then activated in CO2 for 1 h. This two-step activation process provided both a high bulk density (0.69 g/cm3) and a highly textured structure (BET specific surface area, 943 m2/g; total pore volume, 0.56 cm3/g). The immersion in BS syrup was useful for improving the texture without reducing the bulk density, in comparison to one-step activation for 1.0 h. The suspension of the RBCs was basic because of the residual inorganic compounds of potassium and calcium. However, the basicity of the suspension was alleviated by washing the RBCs with water. 相似文献
160.
Kohei Urasaki Ken-ichiro Endo Tomoki Takahiro Ryuji Kikuchi Toshinori Kojima Shigeo Satokawa 《Topics in Catalysis》2010,53(7-10):707-711
Selective methanation of CO in the reformate gas (CO/CO2/H2/H2O = 0.175/17.9/70.9/11.1) proceeded over Ru catalysts supported on metal oxides and zeolites. CO was selectively methanated at wide temperature ranges (200–275 °C) over Ru/γ-Al2O3, Ru/TiO2 Ru/H-Y and Ru/H-beta catalysts. Higher Ru contents in Ru/γ-Al2O3 improved the selective CO methanation rate. 相似文献