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排序方式: 共有619条查询结果,搜索用时 15 毫秒
11.
Summary The synthesis of poly(-thiophenediyl)benzylidene (PTB) with high molecular weight is described. Number-average degrees of polymerization reached about 74. The characterizations of the polymer was investigated by 1H-NMR, 13C-NMR, IR, and UV-VIS spectra. The polymer with well-defined structure and high molecular weight was obtained by polymerization at low temperature and in polar solvent. This polymer was thermally stable and a thermal decomposition took place at 391°C under nitrogen and at 370°C under air. The glass transformation temperature was 117°C and this PTB was nonfusible. 相似文献
12.
Satoshi lio Masakazu Watanabe Masaru Matsubara Yasushi Matsuo 《Journal of the American Ceramic Society》1989,72(10):1880-1884
The improvement of mechanical properties of Al2 O3 /SiC whisker composites has been studied with emphasis on the effects of the whisker content and of the hot-pressing temperature. Mechanical properties such as fracture toughness and fracture strength increased with increasing whisker content up to 40 wt%. In the case of the high SiC whisker content of 40 wt%, fracture toughness of the sample hot-pressed at 1900° decreased significantly, in spite of densification, compared with one hot-pressed at 1850°. Fracture toughness strongly depended on the microstructure, especially the distribution of SiC whiskers rather than the grain size of the Al2 O3 matrix. 相似文献
13.
Ling Xiao Jinlong Zhang Ye Cong Baozhu Tian Feng Chen Masakazu Anpo 《Catalysis Letters》2006,111(3-4):207-211
Fe3+ doped together with Au deposited TiO2 (Au/Fe3+–TiO2) was successfully prepared, which shows excellent photocatalytic activity for degradation of methyl orange (MO) under both
UV and visible light (λ > 420 nm) illumination. Fe3+ has been confirmed by EPR to substitute for Ti4+ in the TiO2 lattice, and Au exists as Au0 on the surface of the photocatalyst indicated by the results of XRD. Fe3+ and Au have synergistic effects on improving the photocatalytic activity of TiO2. A proposed mechanism concerning the synergistic effects is discussed to explain the improvement of the photocatalytic activities. 相似文献
14.
Hiroshi Mori Noritaka Mizuno Masahiro Tajima Shuichi Kagawa Masakazu Iwamoto 《Catalysis Letters》1991,10(1-2):35-39
Proton exchanged ultrastable Y-type zeolite with silica/alumina = 40 showed a pronounced catalytic activity for the formation of ethyl methyl ketone directly from 1-butene and water. The formation rate of ethyl methyl ketone was much higher than those on MoO3-based catalysts in the oxidation of 1-butene by oxygen. It was suggested that the basic site necessary for the formation of ethyl ketone directly from 1-butene and water would be the pentacoordinated Al. 相似文献
15.
Summary Segmented polymers with random sequences of conjugated and non-conjugated blocks are produced by partial dehydrogenation of poly(-thiophenediyl)benzylidene. The fraction of conjugated block was controlled by the elimination time. The polymers gave photoluminescence. Absorption coefficients of the polymers increased with the rate of dehydrogenation, and the highest fluorescence intensity were achieved around 9 % conjugation conversion. The polymers were characterized by 1H- and 13C-n.m.r. and infrared spectra, and were soluble in common organic solvents, which suggests a good processability. 相似文献
16.
17.
Watanabe M Takemasa I Kawaguchi N Miyake M Nishimura N Matsubara T Matsuo E Sekimoto M Nagai K Matsuura N Monden M Nishimura O 《Proteomics. Clinical applications》2008,2(6):925-935
In the development of novel biomarkers, the proteomic approach is advantageous because using it the cancer-associated proteins can be directly identified. We previously developed a 2-nitrobenzenesulfenyl (NBS) method to improve quantitative proteome analysis. Here, we applied this method to proteomic profiling of colorectal carcinoma (CRC) to identify novel proteins with altered expression in CRC. Each pair of tumor and normal tissue specimens from 12 CRC patients was analyzed, and approximately 5000 NBS-labeled paired peaks were quantified. Peaks with altered signal intensities (>1.5-fold) and occurring frequently in the samples (>70%) were selected, and 128 proteins were identified by MS/MS analyses as differentially expressed proteins in CRC tissues. Many proteins were newly revealed to be CRC related; 30 were reported in earlier studies of CRC. Six proteins that were up-regulated in CRC (ZYX, RAN, RCN1, AHCY, LGALS1, and VIM) were further characterized and validated by Western blot and immunohistochemistry. All six were found to be CRC-localized, either in cancer cells or in stroma cells near the cancer cells. These results indicate that the proteins identified in this study are novel candidates for CRC markers, and that the NBS method is useful in proteome mining to discover novel biomarkers. 相似文献
18.
The effect of stress on creep rate of austenitic stainless steels of type 347 and 316 was studied by applying the differential test technique. It was found that the creep rate could be expressed as follows, whereB 1 is a material constant depending on temperature,a 1 anda o are constants, and σ is the real stress. Considering the increase in real stress during creep process due to void formation and to the decrease in cross sectional area of the specimen, integrating the above equation yields the following creep curve, 1 $$ \in = \in _m + \frac{1}{{n_o \left( {c_o + 1} \right)}}ln\frac{1}{{1 - n_o \left( {c_o + 1} \right) \in _m (t - t_{_m } )}}$$ where ∈ is the creep strain at a given time (t), ∈m is the minimum creep rate, ∈m andt m are the strain and time, respectively, at the minimum creep rate,n o is a constant, andc o is the material constant relating to the void formation. This equation agrees very well with the experimental creep curve. 相似文献
19.
20.
Yoshitaka Shingaya Tomonobu Nakayama Masakazu Aono 《Science and Technology of Advanced Materials》2004,5(5-6):647
Nanorods of substoichiometric tungsten oxide (WOx) were grown on W(001) substrates. Two methods for the growth of nanorods were used: oxidation of the substrate under appropriate conditions and the deposition of tungsten oxide from a tungsten foil heated in the presence of oxygen. The grown nanorods were observed using a scanning electron microscope and an atomic force microscope. The diameters of the nanorods were 5–20 nm. The nanorods were slightly inclined from the directions parallel or normal to the surface. The inclination of nanorods was explained in terms of the epitaxial relationship between WO3 crystals and the W(001) substrate. The WO3 crystals formed at the initial stage of growth act as the nuclei of WOx nanorods. We observed selective enhancement of the growth in a certain epitaxial direction depending on the method of growth, and an array of WOx nanorods was produced on the W(001) substrate. 相似文献