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121.
Numerical and experimental investigation of laser propulsion 总被引:3,自引:0,他引:3
Y. Ogata T. Yabe T. Ookubo M. Yamaguchi H. Oozono T. Oku 《Applied Physics A: Materials Science & Processing》2004,79(4-6):829-831
Aiming at the application of laser propulsion to stratospheric flight, we propose here a repetitive propulsion system, friction-less environment and metal-free ablation in a water cannon target. A special reservoir of water is proposed to supply a definite amount of water only at the time of laser irradiation. This system is tested for the object levitated on the airflow, which is called air-slider in order to simulate friction-less environment. In order to avoid the evaporation and freezing of water in lower atmospheric pressures, we propose here an air curtain system. We have performed simulations and experiments and confirmed that a small amount of air flow can sustain the high pressure inside the water reservoir. PACS 42.62.Cf; 52.38.Mf; 07.87.+v 相似文献
122.
123.
Anna Carlsson Takeo Oku Jan-Olov Bovin Reine Wallenberg Jan-Olle Malm Günter Schmid Thomas Kubicki 《Angewandte Chemie (International ed. in English)》1998,37(9):1217-1220
The exact three-dimensional structure of a nanosized colloidal particle of Pd3P was determined directly from high-resolution transmission electron microscopy (HRTEM) images that were recorded in several crystallographic directions. An HRTEM image recorded along [011] is shown on the right. The cores of the particles were excluded from the analysis because of severe multiple diffraction. 相似文献
124.
Takeo Oku Takanori Hirano Satoru Nakajima Katsuaki Suganuma Eiji Aoyagi Kenji Hiraga 《Molecular Crystals and Liquid Crystals》2013,570(1):799-804
Abstract Formation of carbon nanocapsules with various clusters (SiC, Au, Fe. Co. Ge. and GeO2) by polymer pyrolysis was investigated, and nanocapsules with SiC and Au nanoparticles were produced by thermal decomposition of polyvinyl alcohol at ?500°C in Ar gas atmosphere. The formation mechanism of nanocapsules and a structural model for the nanocapsule/SiC interface were proposed. In addition, carbon clusters were formed at the surface of carbon nanocapsules, and carbon onions were produced by electron irradiation of amorphous carbon produced from polyvinyl alcohol. The present work indicates that the pyrolysis of polymer materials with clusters is a useful fabrication method for the mass-production of carbon nanocapsules and onions at low temperatures compared to the ordinaly are discharge method. 相似文献
125.
Abstract— Quenching of excited state of Ru(bpy)2 (poly-4-methyl-4'-vinyl-2,2'-bipyridine)Cl2 by sodium anthraquinone-2-sulfonate was found to be a static process. The quenching was interpreted by application of a modified Perrin model. Radius of the quenching sphere was estimated to correspond to 6.65 monomer units and was unchanged on varying the Ru2 + content of the polymer. Energy migration along the polymer chain was denied. 相似文献
126.
Covalently linked dimers of Ru(bpy)3 2+ (3 and 4) connected by two or three carbon atoms were synthesized as models for Ru(bpy)3 2+-containing vinyl polymer (1). The luminescence properties of 3 and 4 were compared with those of its component monomer, 4,4′-dimethyl-2,2′-bipyridine-bis(2,2′-bipyridine)ruthenium(II) complex (2). In excited 3 and 4, intramolecular interaction leading to enhanced quenching was not observed. Electron-transfer quenching of the excited dimer with methylviologen (MV2+) and the zwitterionic viologen, 1,1′-bis(3-sulfopropyl)4,4′-bipyridinium (SPV), was studied and compared with that of 1 and 2. The low quenching efficiency in 1, 3, and 4 systems can be ascribed to the steric hindrance of unexcited ruthenium complex. Energy migration between ruthenium complexes in the excited 1, 3, and 4 can be ruled out from the kinetic evidence. 相似文献
127.
Masako Yamada Yoshihisa Iwashita Masahiro Ichikawa Takanori Sugimoto Hiromu Tongu Hiroshi Fujisawa Hirohiko M. Shimizu Takashi Ino Kenji Mishima Kaoru Taketani Tamaki Yoshioka Suguru Muto Takahiro Morishima Takayuki Oku Jun-ichi Suzuki Takenao Shinohara Kenji Sakai Hiromi Sato Katsuya Hirota Yoshie Otake Yoshichika Seki Shinsuke Kawasaki Sachio Komamiya Yoshio Kamiya Hidetoshi Otono Satoru Yamashita Peter Geltenbort 《Physica B: Condensed Matter》2009,404(17):2646-2651
Modulating permanent magnet sextupole lens (PMSx) for focusing pulsed cold neutrons is under development. The synchronized modulation of its field gradient suppresses the chromatic aberration which arises from the Time Of Flight method. The strength of the magnetic field, the torque, and the rise of temperature during its operation are studied on a fabricated prototype. Experiments on focusing pulsed very cold neutrons (VCN) at ILL (Institute of Laue Langevin, France) were carried out and VCN with around λ=40 Å were focused by the PMSx at a focal length of about 0.5 m. The experimental results are presented in conjunction with the principle of the neutron focusing and the modulating method of the focal strength of permanent magnet lens with the double ring structure. 相似文献
128.
Takenao Shinohara Jun-ichi Suzuki Takayuki Oku Shin-ichi Takata Hiroshi Kira Kentaro Suzuya Kazuya Aizawa Masatoshi Arai Toshiya Otomo Masaaki Sugiyama 《Physica B: Condensed Matter》2009,404(17):2640-2642
Small-angle neutron scattering technique using polarized neutrons is powerful for studying structures in the range between nm and μm of magnetic materials. In addition, they have been used for the incident beam of focusing-geometry SANS instruments using a magnetic neutron lens, where a high polarization degree of about 99.9% is necessary because the imperfectness of the neutron polarization increases the background level. We are going to install such a magnetic focusing system on the new time-of-flight SANS (TOF-SANS) instrument at the J-PARC so as to make qmin smaller than 10−3 Å−1 and improve the resolution of the conventional TOF-SANS at low q. As a polarizing device of the instrument, two V-shaped polarizing super mirrors arranged in crossed geometry to enhance the polarization degree has been considered. In this paper, we present the concept and the detailed design of this device and its performance estimated by Monte Carlo simulations. 相似文献
129.
Ikumi Sugiyama Saki Kojima Naoto Oku Yasuyuki Sadzuka 《Colloid and polymer science》2010,288(12-13):1293-1300
It has been shown that lifestyle-related diseases and aging are related to reactive oxygen species (ROS), and many studies have reported on the direct detection of ROS. The topical fluorescence reagent 2,7-dichlorodihydrofluorescein (DCDHF) is used to measure oxidation. However, there are problems regarding its stability, and its similar sensitivity to ROS cannot be easily distinguished. In this study, we used hydroxyphenyl fluorescein (HPF), which is a novel fluorescence probe with high stability against light that undergoes specific reactions with highly ROS (hROS). We examined the specificity for hROS of HPF solution and liposomal HPF in different reactions. HPF containing high cholesterol liposomes (HC-H-lipo) maintained its ability to tolerate light scattering energy, dependent on the turbidity of this solution, but DCDHF did not. In the reaction with hydroxyl radicals, the fluorescein concentration in HC-H-lipo was increased compared with that in HPF solution. In contrast, in the reaction with peroxynitrite, HC-H-lipo was inhibited. It was confirmed that HC-H-lipo that reacted specifically with hydroxyl radicals was able to distinguishably detect hydroxyl radicals. It was regarded to be useful as an examination kit. Tissue disorder induced by sodium valproate (SV) was one of the prepared murine disease models. The reactivity ratio of HC-H-lipo with serum to that of HPF solution was markedly different between the normal group (30%) and SV group (70%). In conclusion, HC-H-lipo cannot only simply and directly detect ROS but can also selectively detect ROS type. This nanocarrier is expected to be used as a novel diagnosis method. 相似文献
130.
Jun Nishimura Tomohisa Okuda Yoshihiko Mukai Hidetoshi Hashiba Akira Oku 《Tetrahedron letters》1984,25(14):1495-1498
1,3-bis(4-vinylnaphthyl)propane and 1-(4-vinylnaphthyl)-3-(-vinylphenyl)propane, were cyclocodimerized with indene to afford indenyl-substituted [3.3](1,4)naphthalenophanes and [3.3]paracyclo(1,4)naphthalenophanes. 相似文献