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41.
Oguchi T Tozuka Y Hanawa T Mizutani M Sasaki N Limmatvapirat S Yamamoto K 《Chemical & pharmaceutical bulletin》2002,50(7):887-891
The solid-state complexation between cholic acid (CA) and either methyl p-hydroxybenzoate (MPB) or ibuprofen (IBP) was investigated. Powder X-ray diffractometry, IR spectroscopy and thermal analysis suggested the complex formation between CA and MPB as well as between CA and IBP by co-grinding method. The stoichiometry of CA-MPB was 1 : 1 while that of CA-IBP was 2 : 1, reflecting the effect of guest size on complex formation. The guest compounds were assumed to be included in the channel of complexes formed by hydrogen bonds among CA molecules. 相似文献
42.
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
43.
Itoh T Shichi T Yui T Takahashi H Inui Y Takagi K 《The journal of physical chemistry. B》2005,109(8):3199-3206
The present study is an investigation of a reversible thermal color change induced in lamella hybrids of poly(diacetylenecarboxylates) incorporated in layered double hydroxide (LDH) nanosheets. These poly-[m,n]/LDH hybrids prepared by the photo- or gamma-ray-induced polymerization of diacetylenecarboxylates, i.e., CH(3)(CH(2))(m)()(-)(1)CC-CC(CH(2))(n)()(-)(1)CO(2)(-) (mono-[m,n]), and intercalated in LDH lamella sheets, were observed to develop colors ranging from yellow to blue. The change in color was found to depend greatly on the alkyl carbon numbers of the mono-[m,n] (m,n = 10,11; 5,11; 10,5; 16,1) values. Moreover, the conformational alignment of the mono-[m,n] within the LDH was observed to be a crucial factor in color development, which was greatly affected by the intercalation degrees and extent of poly(ene-yne) linkage elongation of the polymers. For the poly-[m,n]/LDH hybrids investigated, a reversible color change was found to occur repeatedly and remarkably for the poly-[10,11]/LDH hybrid. This color change occurred at temperatures between ca. 20 and 80 degrees C back and forth from purple red to bright orange, in stark contrast to the irreversible color change for poly-[10,11] without LDH. Moreover, DSC and Raman spectroscopic studies of the LDH hybrids showed that the thermochromic temperature corresponded to the phase transition temperature of 80 degrees C. XRD analysis also indicated that the poly-[m,n]/LDH hybrid could retain its lamella structure during such thermochromic color changes, enabling conformational recovery in the polymer chains by a cooling down of the hybrids to temperatures lower than the transition temperature, while the nonhybrid poly-[10,11] powders exhibited an irreversible color change at 60 degrees C, above which the polymer powder turned amorphous. 相似文献
44.
Yoshimoto S Honda Y Murata Y Murata M Komatsu K Ito O Itaya K 《The journal of physical chemistry. B》2005,109(18):8547-8550
Adlayers of ZnOEP were prepared on reconstructed Au(100)-(hex) and unreconstructed Au(100)-(1 x 1) surfaces by immersing into a benzene solution containing ZnOEP molecules, and the adlayer structures were characterized by scanning tunneling microscopy (STM). A hexagonally arranged ZnOEP array was formed on an Au(100)-(hex) surface, whereas a rectangularly arranged ZnOEP array was found on an Au(100)-(1 x 1) surface. The adlayer structure of ZnOEP was dependent upon the underlying Au atomic arrangements. Furthermore, an investigation of the spuramolecular assembly for these modified surfaces was carried out by using an open-cage C(60) derivative (opened C(60)). A supramolecular assembled adlayer with a 1:1 composition of opened C(60)/ZnOEP was formed on Au(100)-(hex), whereas aggregates of opened C(60) were found on the ZnOEP-modified Au(100)-(1 x 1) surface. Electrochemical responses of opened C(60) were significantly influenced by underlying ZnOEP arrays. This finding suggests that precise control of underlying ZnOEP adlayers with the Au atomic structure is important to recognize the opened C(60) on them. 相似文献
45.
Oxidation of alcohols to corresponding carbonyl compounds by coenzyme PQQ-trimethyl ester was performed in the presence of aluminum t-butoxide or aluminum chloride under anaerobic conditions. Reduced PQQTME (PQQTMEH2) was obtained by acidification of an aluminum complex of reduced PQQTME which was isolated in the reaction. 相似文献
46.
47.
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
48.
Kazuhiro Watanabe Noboru Akino Tetsuo Aoyagi Noboru Ebisawa Yukio Fujiwara Atsusi Honda Takashi Inoue Takao Itoh Mikito Kawai Minoru Kazawa Junichi Koizumi Masaaki Kuriyama Kenji Miyamoto Naoki Miyamoto Kazuhiko Mogaki Yoshihiro Ohara Tokumichi Ohga Yoshikazu Okumura Hiroshi Oohara Katsumi Ohshima Fujio Satoh Kazuhiko Shimizu Syunji Takahashi Hirotsugu Usami Katsutomi Usui Masahiro Yamamoto Takeshi Yamazaki 《Radiation Physics and Chemistry》1997,49(6):631-639
A negative-ion-based neutral beam injector (N-NBI) has been constructed for JT-60U. The N-NBI is designed to inject 500 keV, 10 MW neutral beams using two ion sources, each producing a 500 keV, 22 A D− ion beam. In the preliminary experiment using one ion source, a D− ion beam of 13.5 A has been successfully accelerated with an energy of 400 keV (5.4 MW) for 0.12 s at an operating pressure of 0.22 Pa. This is the highest D− beam current and power in the world. Co-extracted electron current was effectively suppressed to the ratio of Ie/ID− < 1. The highest energy beam of 460 keV, 2.4 A, 0.44 s has also been obtained. To realize 1 MeV class NBI system for ITER (International Thermonuclear Experimental Reactor), demonstration of ampere class negative ion beam acceleration up to 1 MeV is an important mile stone. To achieve the mile stone, a prototype accelerator and a 1 MV, 1 A test facility called MeV Test Facility (MTF) were constructed. Up to now, an H− ion beam was accelerated up to the energy of 805 keV with an acceleration drain current of 150 mA for 1 s in a five stage electrostatic multi-aperture accelerator. 相似文献
49.
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
50.
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