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101.
Yoshio Hasegawa Chun-Xiang Feng Yong-Cai Song Zi-Lie Tan 《Journal of Materials Science》1991,26(13):3657-3664
Polycarbosilanes containing titanium alkoxide as pendant groups (atom ratio Ti/Si = 0.07 and 0.15) were synthesized. These polymers were melt-spun and then heat-treated in a vacuum, in oxygen or ammonia gas flow, resulting in Si-Ti-C-O, Si-Ti-0 and Si-Ti-O-N fibres, respectively. The pyrolysis process of the polymer is discussed in connection with the mechanical properties and the structure of the fibre. At high heat-treatment temperatures, -SiC and TiC (in Si-Ti-C-O fibre), anatase (in Si-Ti-O fibre) and TiN (in Si-Ti-O-N fibre) crystallized, which may be closely related to the decomposition of the Si-O-Ti bond in the fibre. 相似文献
102.
Stefan Filipp Yuji Hasegawa Rudolf Loidl Helmut Rauch 《Journal of research of the National Institute of Standards and Technology》2005,110(3):251-257
We present a split-beam neutron interferometric experiment to test the non-cyclic geometric phase tied to the spatial evolution of the system: the subjacent two-dimensional Hilbert space is spanned by the two possible paths in the interferometer and the evolution of the state is controlled by phase shifters and absorbers. A related experiment was reported previously by some of the authors to verify the cyclic spatial geometric phase. The interpretation of this experiment, namely to ascribe a geometric phase to this particular state evolution, has met severe criticism. The extension to non-cyclic evolution manifests the correctness of the interpretation of the previous experiment by means of an explicit calculation of the non-cyclic geometric phase in terms of paths on the Bloch-sphere. The theoretical treatment comprises the cyclic geometric phase as a special case, which is confirmed by experiment. 相似文献
103.
M Yaono R Hasegawa K Kato J Kimura C Lin M Tada T Shirai 《Canadian Metallurgical Quarterly》1996,98(2):145-149
We attempted to purify endogenous growth factors of chick embryonal retinal pigment epithelial cells from bovine neural retina. Ammonium sulfate precipitation, gel filtration, and anion exchange column chromatography were used. Though only partially purification, bovine retinal extract had two effects, growth and transformation, on chick embryonal pigment epithelial cells. We think that these purified factors may be novel from the estimation of their molecular weight by gel filtration. 相似文献
104.
Quaternization of trans-dipyridylporphyrin with 1,4-butaneditrifluoromethane-sulfonate affords new polyionenes containing porphyrin units in the
main chain. The polymers exhibit chemical and electrochemical reversible redox activities. Weitz-type two-step redox processes
similar to those of viologens account for the redox properties of the polymers.
Received: 26 November 1996/Revised: 24 January 1997/Accepted: 10 February 1997 相似文献
105.
Hasegawa T 《Applied spectroscopy》2006,60(1):95-98
Principal component regression (PCR) is unique in that the principal component analysis (PCA) step is explicitly involved in the central part of the method. In the present paper, the PCA part is examined in order to study the influence of noise in spectra on PCR by spectral simulation. It has been suggested, as a result, that PCR calibration would have a large inaccuracy when the estimated number of basis factors analyzed by the eigenvalue method is less than that by cross-validation, which was studied by use of synthesized spectra. This instability is because the minute noise is largely enhanced by the PCA calculation via the normalization of loadings. At the same time, the noise enhancement by PCA has also been characterized to influence the estimation of basis factors. 相似文献
106.
Kyunghun Jung Yuta Yamamoto Shuichi Hasegawa 《Journal of Nuclear Science and Technology》2017,54(11):1261-1266
Excess micromotion of trapped calcium ions was detected and compensated in our linear Paul trap apparatus for trace isotope analysis. The micromotion was detected by Charge-coupled device (CCD). camera and radio frequency (rf) correlation method. We found that 230 and 2280 V of compensation voltages were needed for x- and y-axis compensation in our apparatus, respectively. The z-axis micromotion was confirmed by the experiment and its cause was investigated by finding a shape of z-axis confinement field. The confinement field was indeed distorted in our apparatus and it gave rise to the trapped ion to shift from potential center. And the micromotion of r-direction was transferred to the z-axis by the distorted confinement field. The z-axis micromotion was suppressed by increasing cap voltage of trap. 相似文献
107.
K. Nishizawa H. Kato K. Mimori T. Yoshida N. Hasegawa M. Tsuji Y. Tamaura 《Journal of Materials Science》1994,29(3):768-772
Methanation reactivity was studied for the surface carbon deposited from CO2 on the surface of Rh-bearing activated magnetite. The most active material (Rh=0.83 wt %) for methanation was prepared by the impregnation method at 60°C and showed 98% conversion at 300°C. The surface carbon was composed of elemental carbon (-carbon) and polymerized carbon (-carbon), the proportion being dependent on the density of carbon deposited. In temperature-programmed surface reaction, the extent of conversion of the - and -carbon to CH4 was 0.34 (-carbon) and 0.53 (-carbon), respectively, and the total conversion was 0.87. This result indicates that not only elemental carbon but polymerized carbon (-carbon) could be converted to CH4 on the Rh-bearing activated (-carbon) magnetite, whereas -carbon is not hydrogenated on activated magnetite. 相似文献
108.
Michio Yamada Konomi Tokutomi Ayaka Takehara Yusuke Sakai Yutaka Maeda Tadashi Hasegawa 《Fullerenes, Nanotubes and Carbon Nanostructures》2014,22(1-3):66-74
Tröger's base (TB, 1) and its analogues were synthesized and were subject to the titration experiments to evaluate their ability of supramolecular complexation with C60. Results demonstrate clearly that the fluorene-based TB analogue (2) and the bioctylfluorene-based TB analogue (3) show 1:1 binding with C60 to form the corresponding complexes while TB 1 does not. Titration experiments exhibited that the association constant (Kass) of 3/C60 (48.1 ± 7.9 M ?1) was larger than that of 2/C60 (13.7 ± 1.4 M ?1). The formation of the 1:1 binding complexes 2/C60 and 3/C60 was also confirmed by MALDI-TOF mass spectrometry. Theoretical calculations suggest that 2 and 3 have appropriate cavities to embrace C60. These findings indicate that not only the π/π interaction between the fluorene moieties and the C60 surface but also the CH/π interaction between the octyl groups and the C60 surface serve efficiently in the supramolecular complexation with C60. 相似文献
109.
Naoto Kitamura Takuya Hasegawa Yoshiharu Uchimoto Koji Amezawa Yasushi Idemoto 《Electrochimica acta》2011,(25):9453
LiNi0.5Mn0.5O2 was heat-treated under high oxygen-pressure and Ar-reducing conditions, and then the cathode properties, thermodynamic stability and average and local structures were investigated. From X-ray diffraction and ICP measurements, it was found that the pristine LiNi0.5Mn0.5O2 had a single phase of the layered rock-salt structure although the Ni content was slightly rich compared with the nominal one. These characteristics were kept even after the heat-treatments. Charge–discharge cycle tests clarified that the cycle performance of LiNi0.5Mn0.5O2 was improved by both the reducing and oxidizing treatments. From neutron diffraction and X-ray absorption fine structure measurements, the local distortion around the transition metal, especially Ni, was supposed to be one of the important factors to determine the cathode properties. It was also found that the sample with higher thermodynamic stability exhibited better capacity retention in the discharge–charge cycle tests. 相似文献
110.
A semi-continuous fluidized-bed process is reported which rapidly converts acetylene into carbon nanotubes (CNTs). Catalysts are first immobilized on ceramic beads and CNTs are then grown on the beads and then separated from them in a repetitive process accomplished within a single reactor simply by switching gases at a fixed temperature. CNTs of 6–10 nm diameter, three walls on average, 0.4 mm length and 99 wt.% purity were synthesized at an yield of over 70% in a reactor residence time shorter than 0.3 s. The easy and efficient production of such CNTs with in situ separation from the catalysts may accelerate the development of CNT-based nanotechnology industries. 相似文献