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81.
The magnetic field effect (<800 G) on the hydrogen abstraction of xanthone from xanthene in SDS aqueous micellar solutions was studied using laser flash photolysis. The rate of triplet-singlet intersystem crossing of the radical pair of xanthone ketyl and 9-xanthenyl formed upon photolysis decreases from 1.4 × 106 s?1 at O G to 0.4 × 106 s?1 at 640 G. 相似文献
82.
The anthracene–9, 10–bisketene compound 9, 10-dicarbonyl-9, 10–dihydroanthracene (1) was found to react spontaneously with a variety of benzoquinones and benzoquinone diimines to give aromatic polyesters and polyamides, respectively. These addition reactions are regarded as a novel preparative route to polyarylate and polyaramide. 相似文献
83.
The number of pigments in single light-harvesting complexes (chlorosomes) were calculated by imaging single chlorosomes in a frozen buffer at cryogenic temperature with a confocal laser fluorescence microscope and pigment extraction. Chlorosomes were isolated from two types of green photosynthetic bacteria Chlorobium (Chl.) tepidum and Chloroflexus (Cfl.) aurantiacus and were individually imaged in the frozen medium. Each fluorescence spot observed mainly came from a single chlorosome and was ascribable to self-aggregates of bacteriochlorophyll (BChl) c molecules as core parts of chlorosomes. A three-dimensional distribution of fluorescence of single chlorosomes was analyzed, and the number of chlorosomes in a volume of 54,000 microm(3) was counted directly. On the basis of the results, averaged numbers of the BChl c molecules contained in a single chlorosome of Chl. tepidum and Cfl. aurantiacus were determined to be 1.4 x 10(5) and 9.6 x 10(4), respectively. The present numbers are almost comparable to those estimated by other methods (Martinez-Planells et al., Photosynth. Res. 2002, 71, 83 and Monta?o et al., Biophys. J. 2003, 85, 2560). 相似文献
84.
Masahiko Ogura Norikazu Nakatani Norisuke Yamaji Makoto Imai Akio Itoh Nobutsugu Imanishi 《Radiation Physics and Chemistry》1997,49(6):645-649
We have studied effects of added elements as well as defects on trap-sites of hydrogen in metals. For the purpose, we observed depth profiles and thermal behaviors of hydrogen implanted into Al-1.5 at.% Si alloy samples in an implantation-temperature range of liquid nitrogen temperature (LNT) to 373 K at different doses. The results were compared with those for pure aluminum samples. It was found that hydrogen is trapped as molecules in grain boundaries of Al/Si. 相似文献
85.
Hydrogen atoms adsorbed on Si(111) and Pt(111) were investigated by nuclear reaction analysis (NRA) using 1H(15N,alphagamma)12C. From measurements of the NRA spectrum at normal and tilted ion incidences the zero-point vibrational energies of H on Si(111) in the perpendicular and parallel directions were found to be 123.4+/-4.6 and 44.6+/-6.2 meV, respectively, which are consistent with harmonic potentials. The zero-point energies obtained for Pt(111)-H were 80.8+/-3.9 and 62.1+/-6.0 meV for perpendicular and parallel directions, respectively. These results indicate that the stretching mode is harmonic, while the bending mode is strongly anharmonic. 相似文献
86.
We have developed a spectral interferometric optical coherence tomography (OCT) system with polarization sensitivity that is able to measure a two-dimensional tomographic image by means of one-dimensional mechanical scanning. Our system, which has an axial resolution of 32 mum , calculates the distribution of each element of the Müller matrix of a measured object from 16 OCT images. The OCT system successfully reveals the birefringent nature of human skin tissue. 相似文献
87.
T. Yoshii H. Hara A. Kawamori K. Akabori M. Iwaki S. Itoh 《Applied magnetic resonance》1999,16(4):565-580
Light-induced spin-polarized radical pairs, P700+A1 ? in spinach photosystem (PS) I particles and P680+QA ? in Zn-substituted PS II core complexes, in oriented membranes were studied by pulsed electron paramagnetic resonance (EPR). Based on the determined distance of 25.2 ± 0.2 Å between P700 and A1, the angular dependence of the spin-polarized electron spin echo envelope modulation (ESEEM) spectra on the magnetic field suggests that the angle between $R_{P700 - {\rm A}_1 } $ , the radius-vector connecting P700 and A1, and the membrane normaln was 24 ± 4° in PS I particles. Obtained angle and distance of P700-A1 axis suggested QK side in the molecular geometry of cofactors presented in a recent X-ray crystallography of cyanobacterial PS I reaction center to be an active branch of electron transfer. The distance between P680 and QA was determined to be 27.4 ± 0.3 Å for a nonoriented PS II. The angle between $R_{P680 - Q_{\rm A} } $ , the radius-vector connecting P680 and QA, andn was determined to be 21 ± 5°. The angle of P680-QA axis was close to that of 20° of P870-QA axis reported in X-ray analysis of the purple bacterial reaction center crystal. 相似文献
88.
Hirokazu Tanaka Keizo Yoshida Yoshikuni Itoh Hiroshi Imanaka 《Tetrahedron letters》1981,22(35):3421-3422
The structure elucidation and synthesis of WS-1228 A, produced by , were described. 相似文献
89.
90.
Wavelength dependence of the photocurrent in irradiated naphthalene single crystal was measured and a broad band peaked at 1.8 eV was found. This band was ascribed to the transition of a charge carrier trapped by the radical into a continuum. The width of the continuum was determined as 0.63+0.2-0.05 eV. 相似文献