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71.
Critchley K Jeyadevan JP Fukushima H Ishida M Shimoda T Bushby RJ Evans SD 《Langmuir : the ACS journal of surfaces and colloids》2005,21(10):4554-4561
Surface modification using light is one of the most powerful methods for controlling the physical and chemical properties offunctionalized surfaces. In this paper, we report on systems where soft UV irradiation (lambda = 365 nm) converts a "low" activity fluorocarbon to a "high" activity amine-functionalized surface. An amine-functionalized SAM (self-assembled monolayer) is first masked using a tertiary amine catalyzed reaction with an N-hydroxysuccinimidyl carbonyl reagent. This mild, room-temperature reaction introduces a hydrophobic photocleavable nitrobenzyl "protecting group" terminated with a fluorocarbon end-chain. UV irradiation (lambda = 365 nm) of this hydrophobic/fluorocarbon surface cleaves the nitrobenzyl residue, returning the surface to the original hydrophilic/amine-functionalized state. This provides a mild, generic method of producing surfaces with hydrophilic/hydrophobic patterns or patterned with amine functional residues. Two different protecting groups, one terminated with a single and the other with three fluorocarbon end chains, are compared. In the case of the more bulky protecting group, only a small proportion of the amine residues react, but the surface is equally hydrophobic and the amine residues equally well shielded from further reaction. Surfaces are characterized by X-ray photoelectron spectroscopy, ellipsometry, surface potential, and contact angle measurements. Images of the photopatterned SAMs were obtained using scanning electron microscopy. 相似文献
72.
K. Nishijima 《Physics letters. [Part B]》1982,116(4):295-297
The condition of confinement of quarks and gluons in QCD is derived. It is shown that color confinement is realized when there exist massless scalar color-octet bound states of two Faddeev-Popov ghosts. 相似文献
73.
Treatment of several cyclic olefins, β-pinene, allylbenzene, and estragole with palladium(II) salt in acetic acid in the presence of t-butyl hydroperoxide and tellurium(IV) oxide afforded mainly the corresponding allylic acetates. The reaction proceeded catalytically with palladium(II) salt, t-BuOOH working as a reoxidizing agent. 相似文献
74.
75.
Yasuhiro Matoba Takashi Kagayama Yasutaka Ishii Masaya Ogawa 《Magnetic resonance in chemistry : MRC》1981,17(2):144-147
The 13C NMR spectra of a series of epoxides derived from endo- and exo-dicyclopentadiene and their partially hydrogenated compounds were determined to examine the substituent effects arising from the introduction of the oxirane ring in comparison with those found in other ring systems. The 13C signals of some epoxides were assigned by using lanthanide shift reagents. Characteristic substituent effects exerted by an oxirane ring were demonstrated. Marked steric γ-effects of ?8—13 ppm were observed at the bridge carbon signal in the bicyclo[2.2.1]heptane skeleton. Differences were found in the substituent effects between endo- and exo-dicyclopentadiene epoxides, and have been discussed in relation to the molecular geometry. 相似文献
76.
Lei Wang Yanpeng Qi Dongliang Wang Xianping Zhang Zhaoshun Gao Zhiyu Zhang Yanwei Ma Satoshi Awaji Gen Nishijima Kazuo Watanabe 《Physica C: Superconductivity and its Applications》2010,470(2):183-186
We report the achievement of transport critical currents in Sr0.6K0.4Fe2As2 wires and tapes with a Tc = 34 K. The wires and tapes were fabricated through an in situ powder-in-tube process. Silver was used as a chemical addition as well as a sheath material. All the wire and tape samples have shown the ability to transport superconducting current. Critical current density Jc was enhanced upon silver addition, and at 4.2 K, a largest Jc of ~1200 A/cm2 (Ic = 9 A) was achieved for 20% silver added tapes, which is the highest in iron-based wires and tapes so far. The Jc is almost field independent between 1 T and 10 T, exhibiting a strong vortex pinning. Such a high transport critical current density is attributed to the weak reaction between the silver sheath and the superconducting core, as well as an improved connectivity between grains. We also identify a weak-link behavior from the apparent drop of Jc at low fields and a hysteretic phenomenon. Finally, we found that compared to Fe, Ta and Nb tubes, Ag was the best sheath material for the fabrication of high-performance 122 type pnictide wires and tapes. 相似文献
77.
We demonstrate that ultrasmall double-layer photonic-crystal-slab cavities exhibit a very high-Q value for a wide range of the layer spacing, which enables us to realize unique optomechanical coupling. By mechanically varying the separation, we can achieve extraordinarily large wavelength conversion. In addition, the light stored in the cavity can generate a large radiation force. We show that this system exhibits extremely high energy conversion efficiency between optical and mechanical energy, leading to a novel approach for the optomechanical control of light and matter. 相似文献
78.
Holland C Yu JH James A Nishijima D Shimada M Taheri N Tynan GR 《Physical review letters》2006,96(19):195002
An azimuthally symmetric radially sheared plasma fluid flow is observed to spontaneously form in a cylindrical magnetized helicon plasma device with no external sources of momentum input. A turbulent momentum conservation analysis shows that this shear flow is sustained by the Reynolds stress generated by collisional drift turbulence in the device. The results provide direct experimental support for the basic theoretical picture of drift-wave-shear-flow interactions. 相似文献
79.
80.
Yasunori Nishijima 《Journal of Macromolecular Science: Physics》2013,52(3-4):389-411
The characteristics of photoluminescence are affected by the molecular motions in the local environment of the excited molecule. Hence, by knowing the lifetime of the excited state, various relaxation times of the molecular motions can be estimated from the emission characteristics. In the present paper the effect of the molecular motions manifested in the fluorescence emission, such as the rotational depolarization of fluorescence, the internal quenching of fluorescence due to internal rotation, and the inter-and intramolecular excimer formation, are reviewed and the possible applications of such phenomena to the study of molecular motions in polymer systems are discussed. The application of fluorescence methods provide unique information about the molecular motions in the nanosecond range in polymer solutions, melts, and solids. 相似文献