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71.
The electroreductive polymerization of dichloromethylphenylsilane in the presence of triphenylsilyl group‐containing disilanes such as hexaphenyldisilane followed by the electroreductive termination with chlorotriphenylsilane afforded triphenylsilyl group‐terminated polymethylphenylsilane in 15–32% yield. The isolated polymethylphenylsilane (Mn = 3350 g mol?1, Mw/Mn = 1.4) was found to react as a macroinitiator to copolymerize with dibutyldichlorosilane under electroreductive conditions producing the corresponding block copolymer (Mn = 4730 g mol?1, Mw/Mn = 1.2) in 38% yield. The ratio of monomer units (? MeSiPh? to? BuSiBu? ) of the copolymer was determined to be 75:25 using 1H NMR analysis, which was in good agreement with the calculated ratio (74:26) on the assumption that molecular weight of the macroinitiator was not changed. The block structure of the resulting copolymer, poly(methylphenylsilane)‐block‐poly(dibutylsilane), was also confirmed by comparing its 1H NMR and UV absorption spectra with those of polymethylphenylsilane, polydibutylsilane and a statistical copolymer prepared by electroreductive polymerization of dichloromethylphenylsilane with dibutyldichlorosilane. This method is applicable to the preparation of other types of macroinitiator such as triphenylsilyl group‐terminated polydibutylsilane, and polydibutylsilane‐block‐polymethylphenylsilane was also obtained using this macroinitiator. Copyright © 2011 Society of Chemical Industry 相似文献
72.
Lanthanide(lII) chelates with 1,1,1 -trif luoro-5,5-dimethyl-2,4-hexanedione form adducts with benzilic acid, an a-hydroxycar-boxylic acid, in chloroform. The order of. the adduct formation constants in magnitude is: Lam> Eum> Ybm although it is known that the stability constant of lanthanide(III) complexes with α-hydroxycarboxylic acids in aqueous solutions increases with increasing atomic number. 相似文献
73.
Takao Yasui Noritada Kaji Yukihiro Okamoto Manabu Tokeshi Yasuhiro Horiike Yoshinobu Baba 《Microfluidics and nanofluidics》2013,14(6):961-967
Recent developments of nanofabrication techniques have created a trend switching from randomly ordered polymeric matrices, such as gel, to highly ordered sieving nanostructures in the separation of biomolecules. These nanostructures have enormous potential for fast separation of biomolecules, while nanostructure-based separation techniques suffer from critical scaling problems; they are efficient in handling less than nanoliter amounts of sample fluids, but most biomolecule samples are available in a liquid volume that is over several microliter, leading to a reduction in sensitivity and resolution. In this study, we developed a nanopillar array chip integrated with an easy and rapid on-line stacking method and achieved fast DNA separation with high sensitivity and high resolution. The developed on-line stacking method is based on the balance of two forces driven by electric fields: electroosmotic flow (EOF) and electrophoresis. The EOF mobility from the microchannel to the nanopillar-channel is drastically decreased, while, on the other hand, electrophoresis has constant mobilities in the whole length of the channels. The on-line stacking was realized at the well-balanced position of the two forces, and the on-line stacking using the nanopillar array chip can also be achieved within 10 s by just applying electric voltages without any other special reagents and materials. After applying on-line stacking using the nanopillar array chip, the relative fluorescence intensity increased 1,000-fold, and the resolution was twice as good as that without on-line stacking. 相似文献
74.
Takehiko Tsukahara Hiroyasu Hotokezaka Masayuki Harada Yoshikuni Kikutani Manabu Tokeshi Yasuhisa Ikeda 《Microfluidics and nanofluidics》2013,14(6):989-994
We have developed a novel microchip equipped with a microchannel and Pt microelectrode array for electrochemically controlling valences of actinide (An) species. The square wave voltammograms of the redox reaction of potassium hexacyanoferrate(II) in the microchannel were measured. We found that the fabricated Pt microelectrode array has superior performances for the detection of the electrochemically active species in the microchannel. Therefore, the potentiostatic electrolysis experiments of uranium ions were carried out in the microchannel, and the concentration changes of uranium ions accompanied by the potentiostatic electrolysis were examined using thermal lens microscope. The results showed that the redox reactions between U(VI) and U(IV) can be performed completely in a microchannel in a few minutes, that is, the microscale reaction is accelerated by a factor of more than 10 compared with the bulk solution reactions taking hours mostly. The developed microchip was found to have enough performances for realizing rapid and highly efficient redox reactions for An species, which are impossible in the bulk reactions. 相似文献
75.
76.
Manabu Miyamoto 《Open Systems & Information Dynamics》2006,13(3):291-300
Long time behaviour of the survival probability for unstable multilevel systems is studied based on the N-level Friedrichs model in the presence of zero energy resonance, that means the divergence of the resolvent at zero energy. With resort to the technique developed by Jensen and Kato [Duke Math. J. 46, 583 (1979)], the zero energy resonance of this model is characterized by the zero energy eigenstate that does not belong to the Hilbert space. It is then shown that for some kinds of the form factors, logarithmically slower decay of the survival probability can be realized. 相似文献
77.
Summary
Introduction of simple alkyl groups at the C-2 nitrogen of chitin and some properties of the resulting N-alkyl-chitins have been examined. Chitosan was fully deacetylated and treated with three kinds of aldehydes, formaldehyde,
acetaldehyde, and pentanal. The Schiff bases of chitosan, whose extents of substitution were dependent on the amount of aldehydes,
were reduced with sodium cyanoborohydride to N-alkylated chitosans. The N-alkyl-chitosans were then transformed into the corresponding N-alkyl-chitins by acetylation with acetic anhydride followed by transesterification to remove partly formed O-acetyl groups. The resulting N-methyl-, ethyl-, and pentyl-chitins were amorphous and showed improved affinity for organic solvents.
Received: 13 December 2001/Revised version: 11 January 2002/Accepted: 17 January 2002 相似文献
78.
M TANAKA 《Journal of Materials Science》1997,32(7):1781-1788
The effect of the grain-boundary microstructures on the creep-rupture properties and the initiation and growth of the grain-boundary
cracks was investigated using four kinds of specimen of various grain-boundary microstructures in the cobalt-base HS-21 alloy
at 1089 K in air. Both the rupture strength and the creep ductility increased with increasing mean value of the fractal dimension
of the grain boundaries, Dgb. The strain to crack initiation was largest in the specimen of the highest value (1.241), while
the strain was much the same in the specimens of the Dgb value less than 1.162. This was explained by the local variation
in the grain-boundary microstructures in these specimens. The mean value of the fractal dimension of the grain-boundary fracture,
Df, was close to the value of Dgb, although the value of Df was a little higher than that of Dgb in the specimens of the lower
Dgb values. The fracture appearance changed from a brittle grain-boundary fracture to a ductile one with increasing values
of Dgb and Df. The crack-growth rate is the surface-notched specimens decreased with increasing value of Dgb. The threshold
stress intensity factor for crack growth was higher in the specimens with the higher Dgb values.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
79.
Takashi Ogihara Manabu Iizuka Teruaki Yanagawa Nobuo Ogata Kokichi Yoshida 《Journal of Materials Science》1992,27(1):55-62
A reactor system, which continuously hydrolysed the metal alkoxide in an alcohol solution, was designed using an electromagnetic
stirrer and an ageing tube. Several monosized colloidal particles were produced by this reactor system, which had high reproducibility
and reliability for long-term production. The relation between powder characteristics and experimental parameters such as
reagent concentration, mixing rate, ageing time, temperature, was investigated. These parameters had an effect on the particle
size, size distribution, morphology and state of agglomeration. It is possible to control the particle size to between 0.1
and 1.0 μm by varying the experimental conditions. A narrower size distribution of powders was obtained by using an electromagnetic
stirrer with greater flow rate. Physical and chemical properties of monosized colloidal particles obtained by this reactor
were comparable to those of monosized colloidal particles obtained by the batch process. 相似文献
80.
Manabu Iguchi Tsuneo Kondoh Zen-Ichiro Morita Keiji Nakajima Kazuharu Hanazaki Tomomasa Uemura Fujio Yamamoto 《Metallurgical and Materials Transactions B》1995,26(2):241-247
Laser Doppler velocimeter (LDV) measurements were made to clarify the fluid flow behavior in a bath subject to centric bottom
gas injection. Correlations of the axial mean velocity and turbulence components in the gas-liquid two-phase flow region,i.e., in the bubbling jet region, were proposed as functions of the inner diameter of nozzle, gas flow rate, and densities of
gas and liquid. Measured values of the flow rate, momentum, and kinetic energy of water rising upward were approximated satisfactorily
by these empirical correlations. In addition, the Reynolds shear stress was calculated and compared with measured values.
Formerly Graduate Student, Osaka University, 相似文献