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191.
Isotope separations of potassium and rubidium in chemical exchange system with dicyclohexano-18-crown-6 总被引:2,自引:0,他引:2
K. Nishizawa 《Journal of Radioanalytical and Nuclear Chemistry》2001,249(3):569-571
Chemical isotope effects of potassium and rubidium were studied bythe liquid-liquid extraction using a crown ether of dicyclohexano-18-crown-6.The isotope enrichment factors for unit mass difference were 0.0062+0.0013for potassium and 0.0018+0.0005 for rubidium. The correlation between theobtained isotope enrichment factors and the atomic weights was discussed withthe applicable values of literatures for the alkali metals. 相似文献
192.
Takumi Watanabe Yuichiro Nishizawa Haruka Minato Chihong Song Kazuyoshi Murata Daisuke Suzuki 《Angewandte Chemie (International ed. in English)》2020,59(23):8849-8853
The three‐dimensional structure of nanocomposite microgels was precisely determined by cryo‐electron micrography. Several nanocomposite microgels that differ with respect to their nanocomposite structure, which were obtained from seeded emulsion polymerization in the presence of microgels, were used as model nanocomposite materials for cryo‐electron micrography. The obtained three‐dimensional segmentation images of these nanocomposite microgels provide important insights into the interactions between the hydrophobic monomers and the microgels, that is, hydrophobic styrene monomers recognize molecular‐scale differences in polarity within the microgels during the emulsion polymerization. This result led to the formation of unprecedented multi‐layered nanocomposite microgels, which promise substantial potential in colloidal applications. 相似文献
193.
Osamu Nishizawa Hideki Misaka Toyoji Kakuchi Toshifumi Satoh 《Journal of polymer science. Part A, Polymer chemistry》2008,46(4):1185-1191
Norbornene polymerization using the commercially available and inexpensive catalyst system, cyclopentadienylzirconium trichloride (CpZrCl3) and isobutyl‐modified methylaluminoxane (MMAO), were carried out over a wide range of polymerization temperatures and monomer concentrations. For the CpZrCl3 catalyst system activated by aluminoxane with a 40 mol % methyl group and a 60 mol % isobutyl group (MMAO40/60), the polymerization temperature and monomer concentration significantly affected the molecular weight (Mn) of the obtained polymer and the catalytic activity. With an increase in the polymerization temperature from 0 to 27 °C, the catalytic activity and Mn increased, but these values dramatically decreased with the increasing polymerization temperature from 27 to 70 °C, meaning that the most suitable temperature was 27 °C. The CpZrCl3/MMAO40/60 ([Al]/[Zr] = 1000) catalyst system with the [NB] of 2.76 mol L?1 at 27 °C showed the highest activity of 145 kg molZr?1 h?1 and molecular weight of 211,000 g mol?1. The polymerization using the CpZrCl3/MMAO40/60 catalyst system proceeds through the vinyl addition mechanism to produce atactic polynorbornene, which was soluble in chloroform, toluene, and 1,2‐dichlorobenzene, but insoluble in methanol. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1185–1191, 2008 相似文献
194.
Norihiko Nishizawa Satoshi Kume Masakazu Mori Toshio Goto Akira Miyauchi 《Optical Review》1996,3(1):29-33
Characteristics of guided acoustic wave Brillouin scattering in polarization maintaining fibers are investigated theoretically and experimentally. Spectra of polarized and depolarized scattering are measured for two different types of polarization maintaining fibers: the PANDA (polarization maintaining and absorption reducing) fibers and the elliptical-jacket fibers. Calculated results are in agreement with the experimental ones in the low frequency region. 相似文献
195.
K. Suto T. Kimura J. Nishizawa 《International Journal of Infrared and Millimeter Waves》1995,16(4):691-712
Semiconductor Raman laser can act as a heterodyne demodulator of terahertz-band modulated light wave signals in wideband optical communication systems. We have been developing the semiconductor Raman laser with a waveguide structure composed of a GaP core and AlxGa1–xP cladding layers. The tapered waveguide structure can reduce the threshold pump power by increasing the internal pump power density. Fabricated tapered waveguide semiconductor Raman laser have shown the threshold pump power of 160 mW. Discussion is made on the origin of losses as well as the limit of the low pump power operation. 相似文献
196.
Measurements are reported of TZX1 in BCC3 He whose molar volume dependence is obtained in high accuracy. This dependence is described with an empirical spectral density function different from the often used theoretical one consistently with the thermostatic results. 相似文献
197.
The lattice strain and misfit dislocations in a GaAs-GaAlAsP heterojunction were examined. The change in lattice strain with the composition ratio or the position of the crystal was measured, and it was found that some of the misfit dislocations introduced in the heterojunction were edge-type dislocations. The critical thickness of the epitaxial layer for the generation of misfit dislocations was also measured. The critical differential strain between the atomic layers was on the order of several angstroms. The distribution of lattice strain was analyzed by a two-dimensional simple cubic lattice model, and the distribution of differential strain was examined. 相似文献
198.
Miyake T Yoshino S Yamada T Hata K Nishizawa M 《Journal of the American Chemical Society》2011,133(13):5129-5134
Nanostructured carbons have been widely used for fabricating enzyme-modified electrodes due to their large specific surface area. However, because they are random aggregates of particular or tubular nanocarbons, the postmodification of enzymes to their intrananospace is generally hard to control. Here, we describe a free-standing film of carbon nanotube forest (CNTF) that can form a hybrid ensemble with enzymes through liquid-induced shrinkage. This provides in situ regulation of its intrananospace (inter-CNT pitch) to the size of enzymes and eventually serves as a highly active electrode. The CNTF ensemble with fructose dehydrogenase (FDH) showed the oxidation current density of 16 mA cm(-2) in stirred 200 mM fructose solution. The power density of a biofuel cell using the FDH-CNTF anode and the Laccase-CNTF cathode reached 1.8 mW cm(-2) (at 0.45 V) in the stirred oxygenic fructose solution, more than 80% of which could be maintained after continuous operation for 24 h. Application of the free-standing, flexible character of the enzyme-CNTF ensemble electrodes is demonstrated via their use in the patch or wound form. 相似文献
199.
Soichiro Sekine Hirokazu Kaji Matsuhiko Nishizawa 《Electrochemistry communications》2009,11(9):1781-1784
The integration of electrochemical-based biolithography (ECBL) with an ordinary atomic force microscope (AFM) enables in situ lithography adjacent to a single, cultured cell, consequently allowing the morphological shape of the cell to be manipulated. The tip of a commercially available AFM cantilever was modified to serve as an electrode that could generate the oxidant HBrO for local, controlled etching of a cytophobic material (heparin or albumin) previously layered adjacent to a living cell. A NIH-3T3 fibroblast, initially confined to a patterned area, extended along a bioadhesive surface that had been newly exposed using the ECBL-AFM system. 相似文献
200.
Kuriki K Nishihara S Nishizawa Y Yoshinaga T Tagaya A Koike Y Okamoto Y 《Optics letters》2003,28(7):570-572
We report what is to our knowledge the first observation of erbium fluorescence at the optical communication wavelength of 1.5 microm in a perfluorinated medium. Using a Nd:YAG (355-nm) source, we observed fluorescence of the 4I(13/2) - 4I(15/2) transition with a peak wavelength of 1.535 microm and with a full width at half-maximum of 28 nm. These results can lead to new active devices that use all-fluorinated polymers. 相似文献