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31.
Naoya Tate Yang Liu Tadashi Kawazoe Makoto Naruse Takashi Yatsui Motoichi Ohtsu 《Applied physics. B, Lasers and optics》2013,110(3):293-297
Although recent advances in fabrication technologies have allowed the realization of highly accurate nanometric devices and systems, most approaches still lack uniformity and mass-production capability sufficient for practical use. We have previously demonstrated a novel technique for autonomously coupling heterogeneous quantum dots to induce particular optical responses based on a simple phonon-assisted photocuring method in which a mixture of quantum dots and photocurable polymer is irradiated with light. The cured polymer sequentially encapsulates coupled quantum dots, forming what we call a nanophotonic droplet. Recently, we found that each quantum dot in the mixture is preferably coupled with other quantum dots of similar size due to a size resonance effect of the optical near-field interactions between them. Moreover, every nanophotonic droplet is likely to contain the same number of coupled quantum dots. In this paper, we describe the basic mechanisms of autonomously fabricating nanophotonic droplets, and we examine the size- and number-selectivity of the quantum dots during their coupling process. The results from experiments show the uniformity of the optical properties of mass-produced nanophotonic droplets, revealed by emission from the contained coupled quantum dots, due to the fundamental characteristics of our method. 相似文献
32.
Hiroshi Yasuoka Susumu Sasaki Takashi Imai Tadashi Shimizu Yutaka Ueda Koji Kosuge 《Phase Transitions》2013,86(4):183-199
The nuclear quadrupole resonance (NQR) technique has been utilized to characterize the local oxygen coordination of inequivalent Cu sites in YBa2Cu3O6+x(0 ≤ x ≤ 0.91). Essentially, four distinct NQR lines which correspond to 2, 3,4 oxygen coordinated Cu sites in the Cu-O chains and 5 oxygen coordinated Cu sites in the Cu-O planes have been observed. The zero-field NQR frequencies of these are centered at about 30.1, 24.0, 22.0 and 31.5 MHz for 63Cu, respectively. For the antiferromagnetic ordered state (x ≤ 0.3), antiferromagnetic nuclear resonance (AFNR) has been observed at 90 MHz with quadrupole splittings associated with the moment-bearing Cu sites in the Cu-O planes. The relative intensities of these resonance lines depend on the oxygen content, and this gives us a microscopic understanding of the Cu chemistry of this system. 相似文献
33.
By adapting the functional derivative method developed by Kadanoff and Baym to the Hubbard model, a new perturbation method is formulated. The unperturbed state is defined by the two equations which yield Hubbard's results, while the remainder is given by functional derivatives of the Green's functions which are shown to generate a complete perturbation series. Advantages of this method are discussed. 相似文献
34.
Tadashi Okazaki Fumio Sanda Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》1996,34(10):2029-2035
Synthesis and radical ring-opening polymerization of vinylcyclopropane bearing six-membered cyclic acetal moiety, 1-vinyl-4,8-dioxaspiro[2.5]octane (1), were carried out. 1 was prepared by the reaction of 1,1-dichloro-2-vinylcyclopropane and 1,3-propanediol in DMF in the presence of a base. Radical polymerization of 1 was carried out in the presence of an appropriate initiator (3 mol % vs. 1) at 60 and 120°C in degassed sealed ampoules for 20 h. A colorless transparent viscous polymer was obtained by the isolation with preparative HPLC. The structure of poly(1) was determined to consist of two 1,5-ring-opened units and a unit bearing no olefinic moiety. The difference of the activation energies for the ring-opening reaction of the cyclopropane ring calculated by the molecular orbital method could explain the selectivity in the direction of the cleavage of the cyclopropane ring. Acid hydrolysis of poly(1) afforded the corresponding polyketone in quantitative conversion. © 1996 John Wiley & Sons, Inc. 相似文献
35.
36.
A. Casaburi M. Ejrnaes F. Mattioli A. Gaggero R. Leoni N. Martucciello S. Pagano M. Ohkubo R. Cristiano 《Journal of nanoparticle research》2011,13(11):6121-6131
The recent progress in the nanofabrication of superconducting films opens the road toward detectors with highly improved performances.
This is the case for superconducting nano-striplines where the thickness and the width are pushed down to the extreme limits
to realize detectors with unprecedented sensitivity and ultra fast response time. In this way quantum detectors for single
photons at telecommunication wavelengths and for macromolecules such as proteins can be realized. As is often the case in
applied nanotechnology, it is a challenge to make devices with the necessary macroscopic dimensions that are needed to interface
present technologies, while maintaining the performance improvements. For nano-stripline detectors, both the fast temporal
response and the device sensitivity is generally degraded when the area is increased. Here, we present how such detectors
can be scaled up to macroscopic dimensions without losing the performance of the nano-structured active elements by using
an innovative configuration. In order to realize ultrathin superconducting film the nano-layer is growth with a careful setup
of the deposition technique which guarantees high quality and thickness uniformity at the nano-scale size. The active nano-strips
are defined with the state-of-the-art electron beam nanolithography to achieve a highly uniform linewidth. We present working
detectors based on nano-strips with thicknesses 9–40 nm and widths of 100–1000 nm which exhibit unprecedented speed and area
coverage (40 × 40 μm2 for single photon detectors and 1 × 1 mm2 for single molecule detectors) based on niobium nitride thus enabling practical use of this nanotechnology. 相似文献
37.
By applying advanced telecommunication solid state devices to microwave (MW) resonant cavity system for flow chemistry, it becomes possible to heat up low polarity solvents higher than 250 C, that are considered impossible to heat up by MW until now. The resonant cavity system is opening new process windows to production processes of specialty chemicals which require low cost, high yield and high productivity. 相似文献
38.
Photoreaction dynamics of 2-(3-benzoylphenyl)propionic acid (ketoprofen, KP), one of nonsteroidal anti-inflammatory drugs, with histidine in a phosphate buffer solution (pH 7.4) was investigated with the laser flash photolysis. The deprotonated form of KP (KP(-)) was decarboxylated via UV laser excitation to form a carbanion. It was found that histidine accelerates the protonation reaction of the carbanion to 3-ethylbenzophenone ketyl biradical (3-EBPH) for the first time. The experimental results of the photoreaction of KP with alanine as well as the photoreaction of KP with 4-methylimidazole (a part of the side chain of histidine) in methanol, clearly showed that the protonated form of histidine is a key species for the protonation reaction of the carbanion. These series of the initial reactions should result in the occurrence of photosensitization in vivo. The reaction mechanism was discussed in detail. 相似文献
39.
A. Yokoyama S. Morimoto T. Inoue J. Sanada H. Araki T. Saito H. Baba S. Shibata A. Shinohara T. Muroyama Y. Ohkubo 《Journal of Radioanalytical and Nuclear Chemistry》1999,239(1):143-149
Target-like products, that is,191–200Au,185–200Pt, and183–195Ir, from197Au target bombarded with12C ions at the energies of 180, 230, and 400 MeV/u were measured by using off-line gamma-ray spectrometry combined with chemical
separation procedures. Spallation systematics by Rudstam reproduces well the measured cross sections for formation of platinum
and iridium isotopes. It was found that the cross sections of gold nuclides increase with increase of the incident energy
in the range studied and they are enhanced if compared with the reported proton-induced reaction of gold at a similar incident
energy. It is suggested that the electromagnetic dissociation process plays a role for production of such gold nuclides. 相似文献
40.
Hanczyc MM Toyota T Ikegami T Packard N Sugawara T 《Journal of the American Chemical Society》2007,129(30):9386-9391
Fatty acids have been investigated as boundary structures to construct artificial cells due to their dynamic properties and phase transitions. Here we have explored the possibility that fatty acid systems also demonstrate movement. An oil phase was loaded with a fatty acid anhydride precursor and introduced to an aqueous fatty acid micelle solution. The oil droplets showed autonomous, sustained movement through the aqueous media. Internal convection created a positive feedback loop, and the movement of the oil droplet was sustained as convection drove fresh precursor to the surface to become hydrolyzed. As the system progressed, more surfactant was produced and some of the oil droplets transformed into supramolecular aggregates resembling multilamellar vesicles. The oil droplets also moved directionally within chemical gradients and exhibited a type of chemotaxis. 相似文献