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101.
The optimum photon lifetime for the minimum pulsewidth of a gain-switched laser is investigated both analytically and numerically. For a fixed pump power, the shortest pulse can be produced when the laser cavity is optimized to give an optical pulsewidth that is ~2.5 times the photon lifetime. This is in good agreement with experimental results 相似文献
102.
Yasutake Teraoka Hiroshi Ogawa Hiroshi Furukawa Shuichi Kagawa 《Catalysis Letters》1992,12(4):361-366
The coexistence of alkaline earth (Ca and Sr) and transition metal (Fe, Co and Ni) cations with Cu ions in ZSM-5 zeolite is effective in the promotion of the maximum activity and the expansion of the active temperature range for the reduction of nitric oxide with ethene in the presence of excess oxygen. 相似文献
103.
Hitomi Murakami Gunkichi Sato Shuichi Matsumoto Tatsuhiko Hirabayashi Hideo Yamamoto Wallance W. Donald Erik Bachmann 《International Journal of Satellite Communications and Networking》1986,4(3):127-137
This paper describes field test results of multi-channel digital TV transmission using a PSK/FDMA system and the related subjective test results of received TV pictures. The picture quality of the multi-channel 15 or 30 Mb/s transmission for both NTSC and PAL systems through the INTELSAT POR satellite are subjectively evaluated for various bit-error rates. In addition, subjective evaluations were made at various values of earth-station e.i.r.p. to compare the picture quality of digital transmissions with that of current half-transponder FM transmission. 相似文献
104.
Jian-Yu Zheng Shuichi Noguchi Kenjo Miyauchi Masahiro Hamada Kazushi Kinbara Kazuhiko Saigo 《Fullerenes, Nanotubes and Carbon Nanostructures》2001,9(4):467-475
A series of [60]fullerene bis-adducts having a π-electron-rich aromatic ring as a donor in a face-to-face arrangement were synthesized by the bis-cyclopropanation of [60]fullerene with tether-linked bis-malonates. One of the bis-adducts showed a photoinduced intramolecular electron transfer which caused the dramatic quenching of its fluorescence in a polar solvent. 相似文献
105.
Shigeomi Shimizu Tatsushi Yoshida Masatsune Tsujioka Satoko Arakawa 《International journal of molecular sciences》2014,15(2):3145-3153
Programmed cell death (PCD) is a crucial process required for the normal development and physiology of metazoans. The three major mechanisms that induce PCD are called type I (apoptosis), type II (autophagic cell death), and type III (necrotic cell death). Dysfunctional PCD leads to diseases such as cancer and neurodegeneration. Although apoptosis is the most common form of PCD, recent studies have provided evidence that there are other forms of cell death. One of such cell death is autophagic cell death, which occurs via the activation of autophagy. The present review summarizes recent knowledge about autophagic cell death and discusses the relationship with tumorigenesis. 相似文献
106.
Hydrogen production by combining two types of photosynthetic bacteria with different characteristics
Toshihiko Kondo Masayasu Arakawa Tatsuki Wakayama Jun Miyake 《International Journal of Hydrogen Energy》2002,27(11-12)
The double-layer photobioreactor using two types of photosynthetic bacteria, Rhodobacter sphaeroides RV and its reduced-pigment mutant, MTP4, was developed for efficient hydrogen production. The two types of bacteria had different characteristics on light energy, hydrogen production rate and conversion efficiency. MTP4 produced hydrogen more efficiently under high light conditions and RV did so under low light conditions. Illuminated light toward the surface of a photobioreactor quasi-exponentially declines as it penetrates into the reactor. When two types of bacteria were placed using the developed reactor according to this light distribution, the hydrogen production rate reached 3.64 l/m2/h at a light intensity of 500 W/m2 in 24 h and the conversion efficiency of light energy to hydrogen was 2.18%. These values were 33% higher than those of only using RV. The low light in the deep part of the reactor was utilized efficiently, resulting in a higher hydrogen production rate. 相似文献
107.
Takuya Matsumoto Mohammad Hafiz Uddin Sang Hyun An Kazuto Arakawa Eiji Taguchi Atsushi Nakahira Masayuki Okazaki 《Materials Chemistry and Physics》2011
Hydroxyapatite materials are potentially useful for biomedical application, especially as vehicles for functional molecules. Structural control of bulk apatite materials, such as in the fabrication of hollow microspheres or porous structures, has been studied for this purpose. However, control of the internal structure of the source apatite crystal itself is still a challenge. Here, we show that small organic molecules incorporated in apatite crystals act as porogens which control the porous structure of apatite single crystal. The presence of amino acid under apatite synthesis conditions leads to firm bindings and encapsulation of the amino acid in apatite single crystals. Amino acid elimination by heating or electron beam irradiation enhances the pore formation in apatite single crystal. Moreover, incorporation of an acidic amino acid in apatite induces peapod like nanotubes in apatite single crystals. This study suggests the potential of using small organics for nano-structural control of apatite single crystals which would be valuable for enhancing drug loadings or modulating material digestion in vivo. 相似文献
108.
Hitoshi Kusama Yoshinari Konishi Hideki Sugihara Hironori Arakawa 《Solar Energy Materials & Solar Cells》2003,80(2):2533
The influence of alkylpyridines additive to an I−/I3− redox electrolyte in acetonitrile on the performance of a bis(tetrabutylammonium)cis-bis(thiocyanato)bis(2,2′-bipyridine-4-carboxylic acid, 4′-carboxylate)ruthenium(II) dye-sensitized TiO2 solar cell was studied. I–V measurements were performed using more than 30 different alkylpyridines. The alkylpyridine additives showed a significant influence on the performance of the cell. All the additives decreased the short-circuit photocurrent (Jsc), but most of the alkylpyridines increased the open-circuit photovoltage (Voc) and fill factor (ff) of the solar cell. The results of the molecular orbital calculations suggest that the dipole moment of the alkylpyridine molecules correlate with the Jsc of the cell. These results also suggest that both the size and ionization energy of pyridines correlate with the Voc of the cell. Under AM 1.5 (100 mW/cm2), the highest solar energy conversion efficiency (η) of 7.6% was achieved by using 2-propylpyridine as an additive, which was more effective than the previously reported additive, 4-t-butylpyridine. 相似文献
109.
Onur Alparslan Shin’ichi Arakawa Masayuki Murata 《Photonic Network Communications》2011,22(2):172-179
One of the difficulties with optical packet switched (OPS) networks is buffering optical packets in the network. The only
available solution that can currently be used for buffering in the optical domain is using long fiber lines called fiber delay
lines (FDLs), which have severe limitations. Moreover, the research on optical RAM presently being done is not expected to
achieve a large capacity soon. However, the burstiness of Internet traffic causes high packet drop rates and low utilization
in very small buffered OPS networks. We therefore propose a new node-based pacing algorithm for decreasing burstiness. We
show that by applying some simple pacing at the edge or core backbone nodes, the performance of very small optical RAM buffered
core OPS networks with variable-length packets can be notably increased. 相似文献
110.
To functionalize the surface of nanoparticles with phenyl groups for subsequent cross-linking with aromatic molecules by mutual interactions, we prepared functional nanoparticles (d = 3 nm) by silanization with phenyl-triethoxysilane. The nanoparticles had Fe(2)O(3) cores conjugated to phenyl groups; this was confirmed by Fourier transform infrared (FT-IR) spectroscopy and absorption spectrophotometry. The typical C-H and C-C peaks and the absorption at 240 nm, which corresponds to aromatic rings, were detected in the spectroscopic results for the phenyl group-modified nanoparticles. The nanoparticles could ionize aromatic (colchicine, reserpine, and bradykinin peptide) and nonaromatic (L-α-phosphatidylethanolamine,dioleoyl, and polyethylene glycol) molecules by nanoparticle-assisted laser desorption/ionization mass spectrometry. The nanoparticles worked as a selective trap and an ionization-assisting reagent in mass spectrometry for the aromatic molecular targets. 相似文献