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21.
Hiroshi Tachimori Toshio Masuda 《Journal of polymer science. Part A, Polymer chemistry》1995,33(12):2079-2085
1-(p-N-Carbazolylphenyl)-2-phenylacetylene (p-CzDPA) was polymerized by TaCl5–co-catalyst systems (cocatalysts: n-Bu1Sn, Et3SiH, and 9BBN) to produce acetone-insoluble polymers in about 60-70% yields. Poly(p-CzDPA) was a yellowish-orange solid, most part of which was soluble in toluene, chloroform, etc., and its weight-average molecular weights were around 4×105. This polymer formed a tough film by solution casting, and was thermally very stable (the onset temperature of weight loss in TGA in air 470°C). The oxygen per-meability coefficient of the polymer at 25°C was lower than two barrers. The present polymer showed photoconductivity and redox activity. © 1995 John Wiley & Sons, Inc. 相似文献
22.
Osamu Matsuoka 《International journal of quantum chemistry》1973,7(2):365-381
A mathematical analysis is presented of molecular integrals of relativistic interactions in molecules. The integrals are based on Gaussian-type orbitals and include those arising from variation of electron mass with velocity, one-electron Fermi contact interaction, electron spin-same-orbit interaction, electron spin-nuclear spin interaction, electron spin-spin contact interaction, electron spin-other-orbit interaction, electron spin-spin dipolar interaction and electron orbit-orbit interaction. The integrals are expressed in suitable forms for use in computer. It is also pointed out that the integrals are written essentially in terms of the overlap, nuclear attraction, electron repulsion, or field integrals. 相似文献
23.
Etsuo Watanabe Shunsuke Tokimatsu Kenzo Toyama Isao Karube Hideaki Matsuoka Shuichi Suzuki 《Analytica chimica acta》1984
A multielectrode enzyme sensor for the simultaneous determination of adenosine-5′-phosphate (AMP), inosine-5′-phosphate (IMP), inosine (HXR) and hypoxanthine (HX)in fish meat was developed by assembling four enzyme sensors for AMP, IMP, HXR and HX in a flow cell. These compounds were determined from oxygen consumption according to the following reactions: AMP IMP HXR HX Uric acid where AD is AMP deaminase, NT is 5′-nucleotidase, NP is nucleoside phosphorylase and XO is xanthine oxidase. Enzymes were covalently bound to a membrane prepared from cellulose triacetate, 1,8-diamino-4-aminomethyloctane and glutaraldehyde. Sensors for HX, HXR, IMP and AMP were prepared by attaching membranes of XO, XONP, XO NPNT, and of XONPNT and AD, respectively, to four oxygen electrodes. Samples extracted from sea bass, bream, flounder, abalone and arkshell were analyzed within 5 min, from the simultaneous response curves of the four electrodes. Results obtained by the multisensor system were in good agreement with those determined by each single electrode. 相似文献
24.
25.
Perovskite-type barium lithium fluoride (BaLiF3) was synthesized by pyrolysis of metal trifluoroacetates. The reaction temperature necessary for producing a single-phase material was found to be 600°C, which was lower than that for a conventional solid-state reaction or a melting method. Eu-doped BaLiF3 was also prepared and characterized to examine the suitability of trifluoroacetates for precursors in synthesizing homogeneous complex metal fluoride materials. It was demonstrated that trivalent Eu3+, which was used as acetate for a starting material, was reduced to divalent Eu2+ in the pyrolysis process of BaLiF3, as indicated by a broad blue emission due to an allowed 4f65d→4f7 transition at 408 nm with a ultraviolet excitation at 254 nm. The concentration quenching of the blue emission occurred at 5 at% of Eu in BaLiF3, indicating that Eu was homogeneously dispersed in the BaLiF3 host lattice. Mechanisms of the formation and reduction process of BaLiF3 were discussed based on pertinent chemical reactions. 相似文献
26.
Pavel Smirnov Hisanobu Wakita Masaharu Nomura Toshio Yamaguchi 《Journal of solution chemistry》2004,33(6-7):903-922
The structure and complex formation of concentrated aqueous gallium(III) bromide (GaBr3) solutions have been investigated over a temperature range 80–333 K by Raman spectroscopy, X-ray absorption fine structure (XAFS), and X-ray diffraction. The Raman spectra obtained at various [Br?]/[Ga3+] molar ratios and temperatures have shown that complex formation between Ga3+ and Br? occurs as a predominant species, with [GaBr4]? at [Ga3+] as high as 1~2 M (M = mol?dm ?3) and [Br?]/[Ga3+] ratios > ~2, and that cooling of the solutions favors the formation of the aqua Ga3+. The intermediate species were not seen in the Raman spectra. The XAFS data have revealed that the aqua complex has a sixfold coordination as [Ga(H2O)6]3+ with a Ga3+–H2O distance of (1.96 ± 0.02) Å, whereas the [GaBr4]? complex has a Ga3+–Br? distance of (2.33± 0.02) Å, and that vitrification of the aqueous GaBr3 solution at liquid nitrogen temperature shifts the equilibrium toward the aqua complex. The X-ray diffraction data at different subzero temperatures have shown a tendency of decreasing Ga3+–Br? and increasing Ga3+–H2O interactions with lowering temperature, confirming the preference of aqua Ga3+ in the supercooled liquid state as well as in the glassy state. The Ga3+–H2O distance of ~1.8 Å for the tetrahedral coordination was found in a 2.01 M gallium(III) bromide solution with a [Br?]/[Ga3+] ratio of 3.7 and gradually increased to a value of 1.92 Å for octahedral geometry with decreasing temperature, suggesting that equilibrium shifts from [GaBr4]? to [Ga(H2O)6]3+ through intermediate species, [GaBr n ](3?n)+ (n = 2 and 3). The Ga3+–Br? and Br?–Br? distances within [GaBr4]? with an almost tetrahedral symmetry are (2.35± 0.02) and (3.82± 0.03) Å, respectively. The Ga3+ has the second hydration shell at (4.03± 0.03) Å and the hydration of Br? is characterized with a Br?–H2O distance of (3.35± 0.02) Å at all temperatures investigated. 相似文献
27.
Reinosuke Hayakawa Toshio Nishi Kunio Arisawa Yasaku Wada 《Journal of Polymer Science.Polymer Physics》1967,5(1):165-177
Thermal expansion and dielectric relaxation of polyacrylonitrile were measured in the temperature range from ?75 to 152°C. at frequencies from 30 cps to 3 Mc./sec. The thermal expansion curve and the temperature dependence of logarithmic relaxation time both show an inflection at 85°C. An x-ray study by Bohn reveals that this inflection comes from the thermal expansion of the paracrystalline phase of this polymer, and consequently the transition at 85°C. and the associated relaxation are ascribed to molecular motion in the paracrystalline phase. The relaxation strength increases with increasing temperature above this point. The transition is caused by freezing of the bending vibration of chains whereas the relaxation results from rotational vibration. The length of segments in this phase is roughly estimated to be ca. 100 A. by comparing the observed relaxation strength with the theory developed on the basis of the above considerations. 相似文献
28.
Chiral beta-amino esters are synthesized in one-pot from three components, amines, aldehydes, and ethyl bromoacetate, under the rhodium-catalyzed Reformatsky-type reaction condition, where complete diastereoselection is achieved in the nucleophilic addition step of ethyl bromoacetate to the imines prepared in 相似文献
29.
N. Matsuoka N. Momoshima T. Okai Y. Takashima N. Shiraishi 《Journal of Radioanalytical and Nuclear Chemistry》1988,120(1):21-27
A simple and portable apparatus was developed for measurements of85Kr and133Xe that would be released into the atmosphere in an emergency situation of nuclear facilities. The method is based on cryogenic adsorption of these gases on charcoal followed by chromatographic separation from other gases. The85Kr and133Xe recovered from atmospheric air are determined separately by liquid scintillation counting. It takes about 1 hour for the stepwise determination of85Kr and133Xe. The atmospheric concentration of 3·10–3 Ci per m3 air (1.1·102 Bq/m3 air) is measurable for both nuclides with 20% counting error. 相似文献
30.
Transition of the radial electric field by electron cyclotron heating in the CHS heliotron/torsatron