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71.
Miyake H Siviloglou GA Puentes G Pritchard DE Ketterle W Weld DM 《Physical review letters》2011,107(17):175302
We have observed Bragg scattering of photons from quantum degenerate ^{87}Rb atoms in a three-dimensional optical lattice. Bragg scattered light directly probes the microscopic crystal structure and atomic wave function whose position and momentum width is Heisenberg limited. The spatial coherence of the wave function leads to revivals in the Bragg scattered light due to the atomic Talbot effect. The decay of revivals across the superfluid to Mott insulator transition indicates the loss of superfluid coherence. 相似文献
72.
Masai H Fujiwara T Matsumoto S Takahashi Y Iwasaki K Tokuda Y Yoko T 《Optics letters》2011,36(15):2868-2870
The authors have demonstrated white light emission of rare earth (RE)-free Mn-doped SnO-ZnO-P(2)O(5) glass. The RE-free glass shows white light emission with a high value of quantum efficiency (QE) comparable to conventional crystalline phosphor. It is notable that the high QE value is attained for RE-free transparent glass, and the broad emission can be continuously tuned by both the amount of activator and the composition of the glass. Since this glass possesses low-melting property, we emphasize that the glass phosphor will lead to the development of a novel inorganic white-light-emitting device in combination with a solid state UV light-emitting source. 相似文献
73.
Hirokazu KitauraAkitoshi Hayashi Kiyoharu TadanagaMasahiro Tatsumisago 《Solid State Ionics》2011,192(1):304-307
To improve the electrochemical performance of an all-solid-state In/80Li2S⋅20P2S5 (electrolyte)/LiMn2O4 cell, a lithium-titanate thin film was used to coat LiMn2O4. The interfacial resistance between LiMn2O4 and the electrolyte (measured after initial charging) decreased when the LiMn2O4 particles were coated with lithium-titanate. A cell with lithium-titanate-coated LiMn2O4 had a higher capacity than a cell with noncoated LiMn2O4 for current densities in the range 0.064 to 2.6 mA cm− 2. Additionally, a cell with coated LiMn2O4 retained 96% of the 10th-cycle reversible capacity at a current density of 0.064 mA cm− 2 after 50 cycles. 相似文献
74.
75.
We observed the surface morphology of vicinal GaAs(001) after thermal treatment in AsH3/H2 atmosphere by atomic force microscopy (AFM). Clear multiatomic steps were formed under the high temperature thermal treatment. Next, we investigated the mechanism of step bunching during thermal treatment by two experiments from the view point of Ga atom evaporation. One is the selective thermal treatment using a partially masked GaAs wafer, and the evaporation amount of Ga atoms was estimated by AFM. The other is the investigation of photoluminescence (PL) peak energy shifts for AlGaAs/GaAs single quantum wells with a thermal treatment process at the top of the GaAs quantum well layer, compared to those without thermal treatment. These results indicate that the evaporation hardly occurs during the thermal treatment process. Therefore, step bunching phenomena on GaAs(001) vicinal surfaces during thermal treatment are probably caused by migration of the atoms detached from upside steps and their re-incorporation to downside steps. 相似文献
76.
Masataka Sugimoto Hirokazu Hida Takashi Taniguchi Kiyohito Koyama Yuji Aoki 《Rheologica Acta》2007,46(7):957-964
Poly(vinyl chloride) (PVC)/di-isononyl phthalate systems with PVC content of 45.5 (PVC8) and 70.4 wt% (PVC6) were prepared
by a hot roller at 150 °C and press molded at 180 °C. The dynamic viscoelasticity and elongational viscosity of PVC8 and PVC6
were measured in the temperature range from 150 to 220 °C. We have found that the storage and loss shear moduli, G′ and G″, of PVC8 and PVC6 exhibited the power-law dependence on the angular frequency ω at 190 and 210 °C, respectively. Correspondingly, the tan δ values did not depend on ω. These temperatures indicate the critical gel temperature T
gel of each system. The critical relaxation exponent n obtained from these data was 0.75 irrespective of PVC content, which was in agreement with the n values reported previously for the low PVC concentration samples. These results suggest that the PVC gels of different plasticizer
content have a similar fractal structure. Below T
gel, the gradual melting of the PVC crystallites takes place with elevating temperature, and above T
gel, a densely connected network throughout the whole system disappears. Correspondingly, the elongational viscosity behavior
of PVC8 and PVC6 exhibited strong strain hardening below T
gel, although it did not show any strain hardening above T
gel. These changes in rheological behavior are attributed to the gradual melting of the PVC crystallites worked as the cross-linking
domains in this physical gel, thereby inapplicability of the of time–temperature superposition for PVC/plasticizer systems. 相似文献
77.
78.
Ruthenium‐Immobilized Periodic Mesoporous Organosilica: Synthesis,Characterization, and Catalytic Application for Selective Oxidation of Alkanes 下载免费PDF全文
Nobuhiro Ishito Dr. Hirokazu Kobayashi Dr. Kiyotaka Nakajima Yoshifumi Maegawa Dr. Shinji Inagaki Dr. Kenji Hara Prof. Dr. Atsushi Fukuoka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(44):15564-15569
Periodic mesoporous organosilica (PMO) is a unique material that has a crystal‐like wall structure with coordination sites for metal complexes. A Ru complex, [RuCl2(CO)3]2, is successfully immobilized onto 2,2’‐bipyridine (BPy) units of PMO to form a single‐site catalyst, which has been confirmed by various physicochemical analyses. Using NaClO as an oxidant, the Ru‐immobilized PMO oxidizes the tertiary C?H bonds of adamantane to the corresponding alcohols at 57 times faster than the secondary C?H bonds, thereby exhibiting remarkably high regioselectivity. Moreover, the catalyst converts cis‐decalin to cis‐9‐decalol in a 63 % yield with complete retention of the substrate stereochemistry. The Ru catalyst can be separated by simple filtration and reused without loss of the original activity and selectivity for the oxidation reactions. 相似文献
79.
Prof. Hiroshi Watanabe Ming-Long Yao Atsuko Yamagishi Kunihiro Osaki Toshiyuki Shitata Hirokazu Niwa Yotaro Morishima 《Rheologica Acta》1996,35(5):433-445
Linear and nonlinear viscoelastic properties were examined for a 50 wt% suspension of spherical silica particles (with radius of 40 nm) in a viscous medium, 2.27/1 (wt/wt) ethylene glycol/glycerol mixture. The effective volume fraction of the particles evaluated from zero-shear viscosities of the suspension and medium was 0.53. At a quiescent state the particles had a liquid-like, isotropic spatial distribution in the medium. Dynamic moduli G* obtained for small oscillatory strain (in the linear viscoelastic regime) exhibited a relaxation process that reflected the equilibrium Brownian motion of those particles. In the stress relaxation experiments, the linear relaxation modulus G(t) was obtained for small step strain (0.2) while the nonlinear relaxation modulus G(t, ) characterizing strong stress damping behavior was obtained for large (>0.2). G(t, ) obeyed the time-strain separability at long time scales, and the damping function h() (–G(t, )/G(t)) was determined. Steady flow measurements revealed shear-thinning of the steady state viscosity () for small shear rates (< –1; = linear viscoelastic relaxation time) and shear-thickening for larger (>–1). Corresponding changes were observed also for the viscosity growth and decay functions on start up and cessation of flow, + (t, ) and – (t, ). In the shear-thinning regime, the and dependence of +(t,) and –(t,) as well as the dependence of () were well described by a BKZ-type constitutive equation using the G(t) and h() data. On the other hand, this equation completely failed in describing the behavior in the shear-thickening regime. These applicabilities of the BKZ equation were utilized to discuss the shearthinning and shear-thickening mechanisms in relation to shear effects on the structure (spatial distribution) and motion of the suspended particles.Dedicated to the memory of Prof. Dale S. Parson 相似文献
80.
Toshiyuki Fujii Genki Okude Akihiro Uehara Shun Sekimoto Hirokazu Hayashi Mitsuo Akabori Kazuo Minato Hajimu Yamana 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(1):181-187
Distribution behavior of Ce(III), Am(III), and Cm(III) between tri-n-butyl phosphate solution and molten calcium nitrate hydrate Ca(NO3)2·RH2O or molten calcium chloride hydrate CaCl2·RH2O was studied radiochemically. In Ca(NO3)2·RH2O systems, maximum separation factors of Ce and Cm to Am were observed to be 12 (Ce/Am) and 1.7 (Cm/Am). The distribution
ratios of these elements increased with the decrease of water activity in the hydrates, and the extractabilities at the water
deficient region was less sensitive compared to those at the water abundant region. This trend was similar to the coordination
circumstance change observed in electronic absorption spectra of Nd(III) in the hydrates. 相似文献