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1.
2.
meso-Tetra(n-hexyloxycarbonyl)porphyrin was found to be converted into porphine, the mother compound of porphyrins, in a 77% yield when heated in aqueous sulfuric acid at 180 °C over 30 min under an inert atmosphere. The observation demonstrates that the substituted porphyrin serves as a novel and useful precursor for porphine. 相似文献
3.
Partial Auger recombination of the (D0, X) bound-exciton in n-GaAs at 4.2 K during an impact ionization avalanche under an applied pulse voltage has been investigated. The bright photoluminescence (PL)-pattern observed by applying the pulse voltage, characterizes well the formation of a current density filament. The observation of the bright PL spectra inside the current density filament gives a quite new result concerning the partial Auger recombination process of the (D0, X) complex, leaving the neutral donor in the excited states. 相似文献
4.
5.
Takahiro Hosokawa Takanori Kono Toru Shinohara Shun-Ichi Murahashi 《Journal of organometallic chemistry》1989,370(1-3):C13-C16
The oxidative cyclization of 2-(3-pentenyl)phenol catalyzed by [(η3-pinene)PdOAc]2 gives optically active (+)-2-vinylchroman (25% e.e.), while (−)-2-(1-hydroxyethyl)chroman (56% e.e.) is formed as a single diastereomer upon treatment with t-BuOOH in the presence of Ti(OiPr)4 and
-(+)-diethyl tartrate. 2-(2-Butenyl)phenol also undergoes the Ti-promoted asymmetric cyclization to give (2S,1′R)-(−)-2-(1-hydroxyethyl)-2,3-dihydrobenzofuran (29% e.e.). 相似文献
6.
Hasegawa JY Takata K Miyahara T Neya S Frisch MJ Nakatsuji H 《The journal of physical chemistry. A》2005,109(14):3187-3200
Excited states of free-base porphyrin isomers, porphycene (Pc), corrphycene (Cor), and hemiporphycene (hPc), were studied by the Symmetry-Adapted Cluster (SAC)/SAC-Configuration Interaction (CI) method. The absorption peaks of the porphyrin isomers were assigned on the basis of the SAC-CI spectra. The X, Y, X', and Y' bands of the porphyrin isomers, which have weak intensities, are identified. The differences in the Q-band absorptions among the isomers were clearly explained by the four-orbital model. In Cor and hPc, the wave function of the B-band corresponds to the mixture of the four-orbital excitations and the optically forbidden excitation of free-base porphin (P), due to the molecular symmetry lowering in the isomers. The B-band character is described by the five-orbital model in Pc and the six-orbital model in Cor and hPc. Two tetrazaporphycenes and two ring-extended (dibenzo) porphycenes were designed, and the Q-band transition moment was successfully controlled. These examples show that the control of the four-orbital energy levels is the guiding principle for pigment design in porphyrin compounds. 相似文献
7.
Latex piezoelectric immunoassay is a method for detection of agglutination of antibody- or antigen-bearing latex by immunoreaction using a piezoelectric quartz crystal; the agglutination decreases the oscillation frequency of the crystal. This is advantageous in that coating the surface of the crystal followed by fixation of antibody or antigen is unnecessary. There is, however, a drawback, and to improve this, we designed a micro-cell in which only one side of the crystal is exposed to the solution. A method for regenerating the crystal was also devised. Measurement was carried out using a calibration curve of the frequency change against rheumatoid factor activity. The improvement made it possible to use one crystal repeatedly and reproducibility was satisfactory. The calibration curve became almost independent of the crystal used. 相似文献
8.
9.
Icosahedral Al65Cu20Fe15 and Al40Cu9.9Ge25Mn25
57Fe0.1 quasicrystals are studied using57Fe transmission Mössbauer experiments. The spectra are analyzed by distributions of electric-quadrupole interaction accounting for line asymmetries. Temperature dependences of the hyperfine parameters derived comprising average values ofP() distributions, corresponding standard deviations and center shifts are presented in a whole range from 8 to 300 K. 相似文献
10.
Thermodynamically stable Al-Cu-Fe and Fe-doped ferromagnetic Al-Cu-Ge-Mn icosahedral quasicrystals are studied by57Fe transmission Mössbauer spectroscopy and X-ray diffraction experiments. Al65Cu20Fe15 quasicrystalline alloy was subjected to a mechanical grinding (MG) for up to 800 hours in a ball mill. Presence of the amorphous phase which co-exists with the quasicrystalline one is revealed in the early stage of MG. Mössbauer measurements were performed on icosahedral Al40Cu10–x
Ge25Mn25Fe
x
quasicrystal (x0.1; 3) in a temperature range from 10 K to 548 K. It was found that a magnetic transition occurs at about 30 K which is far belowT
c
reported in the literature. It is concluded that AlGeMn ferromagnet which is present in the samples does not affect the magnetic transition observed and the transition is an intrinsic property of the Al-Cu-Ge-Mn host alloy.Samples of icosahedral quasicrystals were kindly provided by Profs. A. Inoue, T. Masumoto and P. H. Shingu. Ball milling was performed in Kyoto University by a courtesy of Prof. P. H. Shingu. This work was supported by the project for priority areas on properties of quasicrystals (No. 01630003) from the Japanese Ministry of Education, Science and Culture. 相似文献