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101.
102.
Tadamasa Toma Yoshio Furuya Wataru Watanabe Kazuyoshi Itoh Junji Nishii Kenichi Hayashi 《Optical Review》2000,7(1):14-17
It is known that local refractive index change occurs when femtosecond laser pulses with extremely high peak power are launched into glass. We focused 130-femtosecond laser pulses of 800 nm into the bulk of glass and examined the shape of the induced refractive index change. We found that the length of the spot of the refractive index change along the optical axis reached about 30 μm despite the diameter being about 2 μm. To estimate the distribution of induced refractive index change, we fabricated Bragg grating by scanning the focused spot and calculated the amount of the change by applying Kogelnik’s coupled mode theory to the measured diffraction efficiencies of the higher order diffracted beams. 相似文献
103.
Uriel Octavio Moreles Vázquez Wataru Shinoda Preston B. Moore Chi-cheng Chiu Steven O. Nielsen 《Journal of mathematical chemistry》2009,45(1):161-174
We discuss three topologically different methods for calculating the surface tension between a flat solid and a liquid from
theoretical and computer simulation viewpoints. The first method, commonly used in experiments, measures the contact angle
at which a static droplet of liquid rests on a solid surface. We present a new analysis algorithm for this method and explore
the effects of line tension on the contact angle. The second method, commonly used computer simulations, uses the pressure
tensor through the virial in a system where a thick, infinitely extended slab of liquid rests on a solid surface. The third
method, which is original to this paper and is closest to the thermodynamic definition of surface tension, applies to a spherical
solid in contact with liquid in which the flat solid is recovered by extrapolating the sphere radius to infinity. We find
that the second and third methods agree with each other, while the first method systematically underestimates surface tension
values. 相似文献
104.
Yoshio Kabe Houjin Hachiya Daisuke Shimizu Kazuharu Suzuki Wataru Ando 《Journal of organometallic chemistry》2009,694(13):1988-10153
The addition of silyl diazomethane (1a-d) to fullerene C60 at room temperature provided the mono-adducts, the bis- and tris-adducts of silyl fulleroid (3a-d) in moderate yields. The structures of the silyl fulleroids were characterized by mass spectroscopy, as well as 1H and 13C NMR. The gated 1H NMR and 13C-1H COLOC analyses of 3a-d showed a correlation between the methine proton resonances and three fullerene carbons. These observations, as well as the 1H NMR chemical shifts of the methine protons, suggest a remarkable diastereoselectivity, with the silyl groups located above a five-membered ring. Two transition states of the thermal nitrogen-extrusion of pyrazoline intermediate (2a) were theoretically obtained, the structures of which disclosed that the diastereoselectivity is a consequence of minimization of the repulsive interaction between the silyl groups and the N2 moiety. The bridgehead CC double bond of the silyl fulleroid is thought to be reactive by POAV analyses. The silyl fulleroids (3a,b) were found to react with singlet oxygen to afford the silyl enol ether (9a,b) via 1,3-silyl migration of a diketone (8a,b). This is the first example of 1O2 oxygenation of fulleroids. 相似文献
105.
106.
Tomoya Iwazaki Ryoujin Obinata Wataru Sugimoto Yoshio Takasu 《Electrochemistry communications》2009,11(2):376-378
Activated carbon prepared from silk fibroin, which is free of metal elements, showed a high catalytic activity for the oxygen-reduction reaction (ORR). The activated carbon had a very high onset potential of Eonset = 0.83 V (vs. RHE) in oxygen-saturated 0.5 M H2SO4 at 60 °C. The ORR on the activated carbon proceeded by a four-electron process in the high-electrode-potential region; this gradually decreased to a 3.5-electron reaction below about 0.6 V (vs. RHE). Only about 1% of nitrogen atoms (mostly quaternary) remained in the activated carbon by heat-treatment at up to 1200 °C are responsible for the high catalytic activity. The open circuit voltage of a polymer electrolyte fuel cell using the activated carbon as the cathode and a platinum/carbon black anode under pure oxygen and hydrogen gases, respectively, both at one atmosphere, was 0.96 V at 27 °C. 相似文献
107.
Hakamata W Nakanishi I Masuda Y Shimizu T Higuchi H Nakamura Y Saito S Urano S Oku T Ozawa T Ikota N Miyata N Okuda H Fukuhara K 《Journal of the American Chemical Society》2006,128(20):6524-6525
Planar catechin analogues having various alkyl side chain lengths were synthesized, and their remarkable antioxidative abilities and alpha-glucosidase inhibitory activities are shown. 相似文献
108.
Papanikolaou D Margadonna S Kosaka W Ohkoshi S Brunelli M Prassides K 《Journal of the American Chemical Society》2006,128(25):8358-8363
The effect of X-ray illumination on the structural properties of the mixed valence Prussian blue analogue CsFe(II)[Cr(III)(CN)6] has been studied by time-dependent high-resolution synchrotron X-ray diffraction. Abrupt isosymmetric phase transitions, accompanied by dramatic volume collapse, were found in the temperature range 245-265 K, induced by sudden Fe(II) spin transitions from the high spin (HS) (4t(2g)2e(g), S = 2) to the low spin (LS) (6t(2g)0e(g), S = 0) configuration. Absorption of X-ray photons generates photoexcited Fe(II)(LS) domains whose size rapidly grows with time until the percolation threshold is reached and the structure collapse is triggered. The persistent character of the optically excited spin crossover states derives from the strong electron-phonon coupling, associated with the large lattice relaxations, which accompany the internal spin rearrangements. It is thus possible to use X-ray light in a controllable and efficient way to induce photoswitching between the ground and hidden or inaccessible excited states in suitably selected multistable materials in the bulk. 相似文献
109.
O3‐NaFe1/2Co1/2O2 shows initial capacity of 160 mAh/g and an average operating voltage of 3.1 V (vs. Na) with good cyclability, and is a promising candidate of the cathode materials for sodium‐ion secondary batteries (SIBs). Here, we found that the cyclability of the slowly‐cooled sample is much worse than that of quenched one, even though the former sample keeps the O3‐type structure. The energy dispersive X‐ray spectroscopy (EDX) images suggest that the slow‐cooled sample (Nax Fe1–yCoy O2) is inhomogeneous in the Fe concentration (1 – y), perhaps triggered by the Na deficiency (1 – x). We ascribed the poor cyclability in the slowly‐cooled sample to the concentration inhomogeneity (Δy). The Δy is further responsible for the fluctuation of the lattice constants (a and c), as revealed by the Williamson–Hall plot. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
110.
Jiaan Zheng Wataru Kobayashi Thomas Hamann Daniel Nürenberg Markus Lührmann Johannes A. L’huillier Richard Wallenstein Helmut Zacharias 《Applied physics. B, Lasers and optics》2014,116(3):549-560
We present a visually intuitive method for higher-order dispersion compensation based on multi-photon interpulse interference pulse scans. The dispersion values obtained from these scans are fed back as a correction to an acousto-optical programmable dispersive filter to compensate residual higher-order dispersions up to fifth order. This method is applied to the dispersion management of a non-collinear optical parametric chirped-pulse amplifier. A grism-pair stretcher is designed based on a global dispersion balance which provides a large stretching factor and supports a spectral bandwidth of up to 320 nm. It is implemented in a two-stage three-pass non-collinear optical parametric chirped-pulse amplifier and stretches 6-fs seed pulses to about 80 ps from 700 to 1,000 nm. The amplified pulses are compressed by material dispersion. Pulses of less than 10-fs duration with a pulse energy of 125 μJ are obtained at 20-kHz repetition rate. 相似文献