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381.
Hitoshi Tamiaki Shizuka MatsunagaYoshichika Taira Ayaka WadaYusuke Kinoshita Michio Kunieda 《Tetrahedron letters》2014
Zinc complexes of methyl 31-demethyl-bacteriopheophorbides-d possessing a 2-(un)substituted ethynyl or ethenyl group at the 20-position were prepared through palladium-catalyzed cross-coupling of their 20-bromide with the corresponding alkyne or alkene. The synthetic zinc 20-substituted 3-hydroxymethyl-131-oxo-chlorins self-aggregated in an aqueous micellar solution to give similar large oligomers as self-aggregates of bacteriochlorophylls in the core part of the main light-harvesting antenna of photosynthetic green bacteria. The zinc 20-ethynyl-chlorin fully gave the self-aggregates, but its 202-substitution disturbed the self-aggregation. The 20-(2-phenyl)ethenyl moieties induced the formation of relatively smaller oligomers as well as residual monomers due to their steric bulkiness. 相似文献
382.
383.
384.
Effect of host crystallinity on lithium extraction/insertion of LiMn2O4 was studied. LiMn2O4 powders with different crystallinity were prepared via lithium-manganese-tartrates by heat treatment at various temperatures above 300 °C. First charge-discharge capacity around 4 V depended on lattice parameter a0 and lattice strain . On the other hand, the first discharge capacity around 3 V was found to be independent of these parameters. 相似文献
385.
Ashis BhattacharjeeKazuya Saito Michio Sorai 《Journal of Physics and Chemistry of Solids》2002,63(4):569-574
Heat capacity of two rare-earth orthoferrites HoFeO3 and LuFeO3 were measured between 1.8 and 200 K. A distinctly large and two small heat capacity anomalies were detected for HoFeO3 under zero magnetic field around 3.3, 53 and 58 K, respectively. The low-temperature anomaly with a peak at 3.3 K is due to the ordering of Ho3+ ions and the estimated magnetic entropy for this transition was favorably compared with the expected (R ln 2). Application of magnetic field significantly affects the positions and the magnitudes of the anomaly at 3.3 K. Energies of low-lying levels of the lowest J-term of Ho3+ ion were roughly estimated through analysis of the Schottky heat capacity. 相似文献
386.
A radio-frequency (RF) ion trap has been constructed for high resolution laser spectroscopy of metallic ions. Ions in externally
generated laser plasma have been directly introduced into the RF ion trap. An Nd:YAG laser is used to vaporize and ionize
sample metals placed behind a ring electrode. Both hyperbolic and cylindrical electrodes are successfully used for confinement
of the ions. Trapped ions are detected either with a quadrupole mass spectrometer or with a photomultiplier for the measurement
of laser-induced fluorescence. Metallic ions such as Ca+, Ba+, La+, Nd+, Tm+, Lu+, and Ta+ have been confined for the time range of several to 20 minutes in the presence of He buffer gas, and a doubly charged ion
Ba2+ for several seconds. Some ions like Nd+, Lu+, Hf+, and Ta+ are found to be highly reactive with background gaseous molecules. 相似文献
387.
Synthesis of microcrystalline silicon (μc-Si) film at an ultrafast deposition rate over 100 nm/s is achieved from SiH4 + He by using a high density microwave plasma source even without employing H2 dilution and substrate heating techniques. Systematic deposition studies show that high SiH4 flow rate and working pressure increase film deposition rate while high He flow rate decreases the rate. On the other hand, crystallinity of deposited Si film decreases with increasing SiH4 or He flow rate and working pressure. Enhancements of gas phase and surface reactions during film deposition process are responsible for the achievement of high deposition rate and high film crystallinity. 相似文献
388.
The reaction of diethyl difluoro(trimethylsilyl)methylphosphonate with arenecarbaldehydes and aryl methyl ketones is effected with the aid of a catalyst. cesium fluoride, at room temperature to afford the title compounds. 相似文献
389.
Michio Sorai Shigemi Murakawa Toshihiro Kotani Hiroshi Suga 《Journal of Physics and Chemistry of Solids》1983,44(12):1133-1139
The heat capacity of a cubane-tetramer, tetra-μ3-methoxy-tetrakis [salicylaldehydato (methanol) nickel (II)] (abbreviated as [Ni(OCH3) (SAL) (CH3OH)]4), has been measured from 0.4 to 288 K. A broad peak centered at 0.85 K was observed. Subtraction of the lattice heat capacity from the observed one brought about another broad peak centered around 13.5 K. The magnetic anomaly is accounted for by a nearest-neighbor intracluster ferromagnetic exchange interaction characterized by and a single-ion zero-field splitting due to biaxial crystalline anisotropy and The tunnel-splitting of the ground vibrational-rotational state is δ = 2.4 J mol?1, which corresponds to a potential barrier of V0 = 2.3 kJ mol?1 when a three-fold symmetry of a methyl-rotator is assumed. Comparison of the heat capacities between the present compound and a similar cubane-tetramer, [Ni(OCH3) (acac) (CH3OH)]4, indicates that among eight methyl-groups the four belonging to methoxy-ligands are concerned with the tunnel-splitting at low temperatures. 相似文献
390.
Michio Ashida Yasukiyo Ueda Teizo Watanabe 《Journal of Polymer Science.Polymer Physics》1978,16(1):179-188
Polypropylene was evaporated on the (001) cleavage faces of alkali halide single crystals, NaCl, KCl, KBr, and KI, under a vacuum of 10?5 torr. Films evaporated on the substrate were found to be composed of low molecular weight polypropylene with a narrow molecular weight distribution. The polypropylene film evaporated on the substrate maintained at 100°C, was composed of rod-like crystals of α form, the (010) plane of which was parallel to the (001) plane of alkali halide and their long axes were oriented in the (110) direction of the substrate. When the substrate was kept above 150°C, the film included three crystalline forms, α, γ, and δ forms. Fiber-like crystals of the α form lay parallel to the (110) direction of NaCl. In the initial stage of growth, lamellar crystals were observed in the film. The lamellar (001) plane lay flat in the film and branching occurred on the (010) lateral faces. Both the γ-form and the (predominately) new δ-form crystals were observed in the same area of the film prepared at temperatures above 150°C. 相似文献