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1.
We will discuss the Gorenstein property of the singularity which is blown down from the minimal section of a ruled surface in terms of the extension class. In the case that the base field has positive characteristic, we find a new example (3.4) of Gorenstein singularity in connection with Theorem B. 相似文献
2.
G. M. Luke L. P. Le B. J. Sternlieb Y. J. Uemura J. H. Brewer R. Kadono R. F. Kiefl S. R. Kreitzman T. M. Riseman C. E. Stronach M. Davis S. Uchida H. Takagi Y. Tokura Y. Hidaka T. Murakami E. A. Early J. T. Markert M. B. Maple C. L. Seaman 《Hyperfine Interactions》1991,63(1-4):311-317
We report muon spin relaxation/rotation measurements on sintered powder samples of Nd2−x
Ce
x
CuO4−y
and a large single crystal of Nd2CuO4−y
. We find an electronic phase diagram which is quite similar to that of hole-doped superconductors such as La2−x
Sr
x
CuO4−y
, although the doping of electrons into the system is less efficient in destroying the static moments on the copper spins.
Static magnetic order in Nd2CuO4−y
appears below about 250 K, and two spin reorientations are seen atT=75 K andT=35 K. Measurements of the magnetic field penetration depth have been unsuccessful due to the rare-earth paramagnetism of
these materials. 相似文献
3.
4.
5.
Katsunori Nishimura Rie Hidaka Fumitoshi Hirayama Hidetoshi Arima Kaneto Uekama 《Journal of inclusion phenomena and macrocyclic chemistry》2006,54(1-2):85-88
Geometries, electronic properties and NMR-shielding of cucurbit[5]uril, decamethylcucurbit[5]uril, cucurbit[6]uril, cucurbit[7]uril,
and cucurbit[8]uril are investigated with DFT calculations. All molecules are highly symmetrical with a distinct geometric
flexibility. In addition with a characteristic partial charge distribution these findings account for their chemical complex
building ability. 相似文献
6.
Masahiko Ishikawa Ken-ichi Okamoto Jinsai Hidaka Hisahiko Einaga 《Helvetica chimica acta》1985,68(7):2015-2021
Substitution reaction with ethylenediamine of coordinated glycinate ligand in bis(ethylenediamine)-glycinatocobalt(III) complex has been studied in the presence of photo-excited tris(2,2′-bipyridine)ruthenium(II) complex in alkaline aqueous solution (buffered around pH 12) containing 1.0M chloride ion at 25°C. VIS absorption and CD spectra were used for the racemate and the optically active isomers of the Co(III) complexes, respectively. The reaction was catalyzed by the excited Ru(II) complex to give tris(ethylenediamine)cobalt(III) complex. Mechanism of the ligand-substitution reaction and role of the excited Ru(II) complex were discussed. 相似文献
7.
Yoshiaki Hidaka Hiromitsu Masaoka Hidekazu Oshita Takuji Nakamura Koji Tanaka Hiroyuki Kawano 《国际化学动力学杂志》1992,24(10):871-885
The thermal decomposition of vinylacetylene (C4H4) was studied behind reflected shock waves using both a single-pulse method (reaction time between 0.8 and 3.3 ms) and a time-resolved UV-absorption method (230 nm). The studies were done over the temperature range of 1170–1690 K at the total pressure range of 1.3–2.3 atm. The mechanism was used to interpret both the early and late stages of vinylacetylene decomposition at the high temperatures. It was confirmed that C4H4 dissociation proceeded through the following three channels. The rate constant expression of reaction (1) was determined as k1 = 6.3 × 1013 exp(?87.1 kcal/RT) s?1. The rate constants of the succeeding reactions (chain reaction, C4H4 + H → i-C4H3 + H2 and C4H4 + H → C2H2 + C2H3 and decomposition reactions of free radicals, i-C4H3 + M → C4H2 + H + M) were confirmed or estimated. © John Wiley & Sons, Inc. 相似文献
8.
Sagara T Nagata K Tsuruta H Nakashima N 《Chemical communications (Cambridge, England)》2002,(18):2116-2117
Potential-dependent dynamic adsorption-desorption and reorientation of a 4-pyridyl modified PAMAM G2 dendrimer at a Au(111) electrode has been demonstrated. 相似文献
9.
Nogita R Matohara K Yamaji M Oda T Sakamoto Y Kumagai T Lim C Yasutake M Shimo T Jefford CW Shinmyozu T 《Journal of the American Chemical Society》2004,126(42):13732-13741
Thephotochemical reaction of [3(3)](1,3,5)cyclophane 2, which is a photoprecursor for the formation of propella[3(3)]prismane 18, was studied using a sterilizing lamp (254 nm). Upon photolysis in dry and wet CH2Cl2 or MeOH in the presence of 2 mol/L aqueous HCl solution, the cyclophane 2 afforded novel cage compounds comprised of new skeletons, tetracyclo[6.3.1.0.(2,7)0(4,11)]dodeca-5,9-diene 43, hexacyclo[6.4.0.0.(2,6)0.(4,11)0.(5,10)0(9,12)]dodecane 44, and pentacyclo[6.4.0.0.(2,6)0.(4,11)0(5,10)]dodecane 45. All of these products were confirmed by the X-ray structural analyses. A possible mechanism for the formation of these photoproducts via the hexaprismane derivative 18 is proposed. The photophysical properties in the excited state of the [3n]cyclophanes ([3n]CP, n = 2-6) were investigated by measuring the emission spectra and determining the quantum yields and lifetimes of the fluorescence. All [3n]CPs show excimeric fluorescence without a monomeric one. The lifetime of the excimer fluorescence becomes gradually longer with the increasing number of the trimethylene bridges. The [3n]CPs also shows excimeric phosphorescence spectra without vibrational structures for n = 2, 4, and 5, while phosphorescence is absent for n = 3 and 6. With an increase in symmetry of the benzene skeleton in the [3(3)]- and [3(6)]CPs, the probability of the radiation (phosphorescence) process from the lowest triplet state may drastically decrease. 相似文献
10.
The photocatalytic degradation for some kinds of dye-constituent aromatics with TiO2 in the presence of phosphate anions in aqueous dispersion was investigated under both visible light (λ>480 nm) and UV irradiation. The influences of phosphate anion upon the degradation of organics under these different conditions was revealed by the measurement of point of zero ξ-potential (P ZC) of TiO2, UV-VIS spectra, HPLC and LC-MS. The adsorption and photodegradation of some organics, which adsorb on the surface of TiO2 by a dominating group bearing a positive charge, was enhanced, while that of others, which adsorb on the surface of TiO2 by a dominating group bearing negative charge, was depressed by the presence of phosphate anions under UV irradiation at the experimental conditions (pH 4.3). It was confirmed that better adsorption of organics on the surface of TiO2 had an advantage in their photocatalytic degradation under UV irradiation. On the other hand, although the adsorption of rhodamine B (RhB) and methylene Blue (MB) markedly increased, their degradation under visible light irradiation was depressed in the presence of phosphate anions. It is suggested that phosphate anion greatly blocked the electron transfer from excited RhB and MB molecules as RhB and MB molecules predominantly adsorbed on the surface of TiO2 through the electrostatic interaction with surface adsorbed phosphate anions. 相似文献