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排序方式: 共有619条查询结果,搜索用时 171 毫秒
31.
M. Matsuoka T. Hayasaka Y. Fukushima Y. Honda 《International journal of remote sensing》2013,34(2):221-248
Land cover is classified over East Asia using 250‐m Moderate Resolution Imaging Spectroradiometer (MODIS) land surface reflectance, MODIS snow cover and Operational Linescan System (OLS) human settlement data. The classification method includes a decision tree classification scheme that considers 11 kinds of land surface features derived from the OLS product and the time series of two MODIS products in 2000. The decision tree was defined manually based on the experiment because of insufficient training data, ease of tuning by visual interpretation, and extensibility to further research. The resulting classification is compared to three kinds of reference data, i.e. MODIS land cover product, Chinese digital land cover map, and Chinese census. The land cover classification can be input into a hydrological model applied to the Yellow River in China. 相似文献
32.
Watanabe I. Torikai T. Makita K. Fukushima K. Uji T. 《Electron Device Letters, IEEE》1990,11(10):437-438
Impact ionization rates for electrons and holes in (100) Al0.48In0.52As were determined from photomultiplication measurements using AlInAs/GaInAs p+-i-n diodes grown by metalorganic vapor phase epitaxy (MOVPE). The impact ionization-rate ratio was derived as being 2.0~3.5 over the electric field range from 400 to 650 kV/cm. Ionization rates were found to be smaller than those previously reported. These results could be useful for designing AlInAs/GaInAs superlattice avalanche photodiodes with an electron-initiated configuration 相似文献
33.
Yasumasa Fukushima 《Polymer Bulletin》2000,45(3):237-244
Summary
Four sequential copolypeptides poly(X-Gly-Gly) with X being Ala, Tyr, Gln, or Leu were prepared as a model of glycine-rich
sequence of dragline spider silk produced by Nephila clavipes and their secondary structures in the solid state were characterized by FT-IR spectroscopy. Poly(Tyr-Gly-Gly), poly(Gln-Gly-Gly),
and poly(Ala-Gly-Gly) form the β-sheet structures, whereas poly(Leu-Gly-Gly) existed as a disordered conformation as a cast
film from formic acid. These results indicated that X-Gly-Gly sequences with Tyr, Gln, and Ala could contribute to the formation
of the β-sheet structure in glycine-rich sequence.
Received: 5 August 2000/Accepted: 24 August 2000 相似文献
34.
Yasuyuki Koyama Ryuzo Takagi Yasuhiko Iwadate Kazuko Fukushima 《Journal of Alloys and Compounds》1997,260(1-2):75-79
A phase diagram of the EuCl2---NaCl system was determined by differential scanning calorimetry (DSC) and the activity coefficients of EuCl2 and NaCl in this system were estimated under some assumptions. According to DSC measurement, it was found that there were two phase transitions at 1123.9 K and 1016.8 K. In order to specify the melting point of EuCl2 we did Raman spectroscopy experiments. Thus, the melting point of EuCl2 was evaluated to be 1016.8 K which was detected as the lower peak in the DSC curve. Raman spectroscopy of this system suggested that complex species were not formed clearly in the EuCl2 poor system and the estimated activity coefficients of EuCl2 also supported this suggestion. 相似文献
35.
Yuki Nakashima You Zhou Keisuke Tanabe Souhei Arima Kiyoshi Hirao Tatsuki Ohji Norimitsu Murayama Manabu Fukushima 《Journal of the American Ceramic Society》2023,106(2):1139-1148
Silicon nitride (Si3N4) was prepared from silicon by a sintered reaction-bonded silicon nitride method using yttria and magnesia as sintering additives. Post-sintering (PS) of nitrided compacts was carried out at 1850°C under a nitrogen pressure of 1 MPa. Effect of PS time on microstructure and dielectric breakdown strength (DBS) of the prepared Si3N4 ceramics was evaluated. The DBS was measured using specimens with four different thicknesses (0.30, 0.20, 0.10, and 0.05 mm) in order to examine the thickness dependence. The porosity of the sintered Si3N4 decreased by prolonging the PS time, and the full density could be achieved at the PS time of over 6 h. After full densification, rod-like β-Si3N4 grains grew up, and their maximum grain size increased from 45.1 to 154.7 μm by prolonging the PS time from 6 to 48 h. The DBS of the thick Si3N4 substrates (0.30 mm) showed little variation from 35.4 to 47.0 kV/mm, regardless of the PS time. On the other hand, that of the thin ones (0.05 mm) dramatically decreased from 99.5 to 9.8 kV/mm with increased the PS time from 6 to 48 h. Because the DBS sharply decreased at the thin substrate sintered for longer time in which some large-elongated grains might span the substrate thickness-wise throughout, it was inferred that the interface between β-Si3N4 grains and grain boundary phase/intergranular glassy films might be a path of the dielectric breakdown. 相似文献
36.
Various four-base codons have been shown to work for the introduction of non-natural amino acids into proteins in an Escherichia coli cell-free translation system. Here, a four-base codon-mediated non-natural mutagenesis was applied to a eukaryotic rabbit reticulocyte cell-free translation system. Mutated streptavidin mRNAs containing four-base codons were prepared and added to a rabbit reticulocyte lysate in the presence of tRNAs that were aminoacylated with a non-natural amino acid and had the corresponding four-base anticodons. A Western blot analysis of translation products indicated that the four-base codons CGGU, CGCU, CCCU, CUCU, CUAU, and GGGU were efficiently decoded by the aminoacyl-tRNAs having the corresponding four-base anticodons. In contrast, the four-base codons AGGU, AGAU, CGAU, UUGU, UCGU, and ACGU were not decoded. The stop codon-derived four-base codons UAGU, UAAU, and UGAU were found to be inefficient, whereas the amber codon UAG and opal codon UGA were efficient for the incorporation of non-natural amino acids. The application of the expanded genetic code in a eukaryotic cell-free system opens the possibility of a four-base codon-mediated incorporation of non-natural amino acids into proteins in living eukaryotic cells. 相似文献
37.
The degradation characteristics and pathways of pentachlorophenol (PCP) by the photo-Fenton systems were studied in H2O2 aqueous solutions, which contained Fe(III) only [H2O2/Fe(III) system] and Fe(III) + humic acid (HA) [H2O2/Fe(III)/HA system] at pH 5.0. Although 40% of the PCP was degraded after 5 h of irradiation in the H2O2/Fe(III) system, more than 90% was degraded in the H2O2/Fe(III)/HA system. This shows that at pH 5.0 the degradation of PCP is clearly enhanced by the presence of HA in the photo-Fenton system. In the H2O2/Fe(III) system, the production of octachlorodibenzo-p-dioxin (OCDD) was detected, and 2-hydroxy nonachlorodiphenyl ether was also identified as a precursor of OCDD. However, no OCDD production was observed in the H2O2/Fe(III)/HA system. This indicates that the presence of HA represses the production of OCDD during the degradation of PCP by the photo-Fenton system. Such an effect by HA can be attributed to a reaction sequence wherein reaction intermediates derived from PCP, such as PCP., are incorporated into HA. This was verified by 13C NMR and pyrolysis-GC/MS studies. 相似文献
38.
The heterogeneous nature of hardwood lignin was shown by visualizing the deposition process of p-hydroxyphenyl (H) lignin in the differentiating xylem of magnolia, beech, lilac and poplar. When p-glucocoumaryl alcohol-[arom. ring-2-3H], an efficient precursor of H units in lignin, was administered to the differentiating xylem of these trees, radioactivity was incorporated in the compound middle lamella region of vessel and fiber cell walls. The deposition of H units occurs only in the early stage of cell wall formation when the outer layer of the secondary wall is formed. H lignin deposits mainly within pectic substances and hemicellulose gel to form a highly condensed structural moiety. 相似文献
39.
We have designed a colorimetric conjugated polymer (PDMAp) for selective ATP sensing based on poly(2,5-dimethoxyaniline) bearing phthalimide which can form hydrogen bonds with adenine. PDMAp have been synthesized via chemical oxidative polymerization with CSA and DDQ and dedoping with an aqueous ammonia solution. PDMAp was displayed to signal the colorimetric selective detection for ATP over various nucleotides such as ADP, AMP, CTP, TTP, and GTP in DMSO–water (9:1, v/v) mixture. The absorption spectral change can be attributed to a doping process of ATP to PDMAp through hydrogen bonds between phthalimide and adenine as well as electrostatic interactions between the phosphate group of ATP and the backbone of PDMAp. 相似文献
40.
M Yamada-Osaki R Sumazaki M Tsuchida K Koike T Fukushima A Matsui 《Canadian Metallurgical Quarterly》1999,93(2):721-727
The natural course and the clinical significance of hepatitis G virus (HGV) infection were investigated in 106 pediatric patients who received chemotherapy for hematological malignancy or underwent bone marrow transplantation (BMT) using HGV-RNA and antibodies to the HGV-E2 protein (anti-E2). HGV markers were detected in 21 patients (19.8%; HGV-RNA in 19 and anti-E2 in 2). Longitudinal analysis of these HGV-infected patients showed that 1 had anti-E2 before the initial blood transfusion, 14 had persistent viremia, and 6 became clear of circulating HGV-RNA after completion of therapy, although 5 of the 6 HGV-cleared patients never developed anti-E2. Reactivation of HGV infection during chemotherapy was observed in two anti-E2-positive, HGV-RNA-negative patients; the reappearance of the same HGV strain was confirmed by phylogenetic analysis. Among BMT survivors without other known causes of liver dysfunction, HGV-RNA-positive patients had a higher peak serum alanine amino transferase (ALT) value than negative patients. Contrary to previous reports, immunosuppressed patients can apparently recover from HGV infection without detectable anti-E2 and some patients who supposedly recovered from HGV infection can nonetheless suffer exacerbation when subsequently immunosuppressed. 相似文献