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排序方式: 共有1013条查询结果,搜索用时 46 毫秒
951.
952.
T. Matsuoka T. Fujimoto K. Tanaka S. Miyasaka S. Tajima K. Fujii M. Suzuki M. Tonouchi 《Physica C: Superconductivity and its Applications》2009,469(15-20):982-984
We have developed a terahertz time-domain spectroscopy (THz-TDS) system for reflectivity measurement with a temperature-controllable cryostat. For emission and detection of THz radiation, a Ti:Sapphire pulsed laser and photoconductive antennas are used. Two wire-grid polarizers enable us to carry out the polarized reflectivity measurements. Using our THz-TDS system, we measured the c-axis polarized reflectivity spectra for La2−xSrxCuO4 single crystals (x = 0.10 and 0.13) and observed sharp Josephson plasma edges for both samples below Tc. The reflectivity spectra of the x = 0.10 sample were in good agreement with those reported previously, which confirms the validity of the system. For the x = 0.13 sample, we discuss the anomolous features of the optical spectra. 相似文献
953.
A relativistic virial theorem is derived for atoms in a general manner. The virial ratio consists of the usual V/T term and a correction term W/T, where T, V, and W are the kinetic energy, the potential energy, and correction terms, respectively. Explicit forms of W are presented for four specific nuclear potential models. Numerical calculations for a uniform nuclear charge model show
that the magnitude of the correction term W/T increases with increasing atomic numbers and that it modifies the ratio V/T considerably for atoms with large atomic numbers in particular.
Received: 21 November 2000 / Accepted: 8 January 2001 / Published online: 3 April 2001 相似文献
954.
Shingo Taniguchi Masashi Takada Takashi Nakamura 《Radiation Physics and Chemistry》2001,61(3-6):523-526
A multi-moderator spectrometer on which is mounted a pair of 6Li and 7Li glass scintillators has been developed as a new type neutron spectrometer which can measure the neutron spectrum in a mixed field of neutrons, charged particles and gamma-rays realized in space. The particle identification capability was investigated in neutron-gamma-ray and neutron-proton mixed fields and the neutron response functions of the spectrometer were obtained by calculations and experiments up to 200 MeV. 相似文献
955.
Critical condition of inner cylinder radius for sustaining rotating detonation waves in rotating detonation engine thruster 总被引:1,自引:0,他引:1
Akira Kawasaki Tomoya Inakawa Jiro Kasahara Keisuke Goto Ken Matsuoka Akiko Matsuo Ikkoh Funaki 《Proceedings of the Combustion Institute》2019,37(3):3461-3469
We describe the critical condition necessary for the inner cylinder radius of a rotating detonation engine (RDE) used for in-space rocket propulsion to sustain adequate thruster performance. Using gaseous C2H4 and O2 as the propellant, we measured thrust and impulse of the RDE experimentally, varying in the inner cylinder radius ri from 31 mm (typical annular configuration) to 0 (no-inner-cylinder configuration), while keeping the outer cylinder radius (ro = 39 mm) and propellant injector position (rinj = 35 mm) constant. In the experiments, we also performed high-speed imaging of self-luminescence in the combustion chamber and engine plume. In the case of relatively large inner cylinder radii (ri = 23 and 31 mm), rotating detonation waves in the combustion chamber attached to the inner cylinder surface, whereas for relatively small inner cylinder radii (ri = 0, 9, and 15 mm), rotating detonation waves were observed to detach from the inner cylinder surface. In these small inner radii cases, strong chemical luminescence was observed in the plume, probably due to the existence of soot. On the other hand, for cases where ri = 15, 23, and 31 mm, the specific impulses were greater than 80% of the ideal value at correct expansion. Meanwhile, for cases ri = 0 and 9 mm, the specific impulses were below 80% of the ideal expansion value. This was considered to be due to the imperfect detonation combustion (deflagration combustion) observed in small inner cylinder radius cases. Our results suggest that in our experimental conditions, ri = 15 mm was close to the critical condition for sustaining rotating detonation in a suitable state for efficient thrust generation. This condition in the inner cylinder radius corresponds to a condition in the reduced unburned layer height of 4.5–6.5. 相似文献
956.
Thomas Delzeit Luca Carmignani Tsuneyoshi Matsuoka Subrata Bhattacharjee 《Proceedings of the Combustion Institute》2019,37(3):3203-3209
This systematic experimental study measures the effect of flame propagation along vertical edges on the overall downward spread of flames using Polymethyl Methacrylate (PMMA). Samples with a wide range of regular cross-sections – from triangular through octagonal – as well as irregular ones, have been used to test a large variation of internal angles. A MATLAB-based tool was used to calculate instantaneous spread rate for central and edge flames. The edge flame is shown to significantly enhance the spread rate, as much as five times, in respect to samples with no edges. This amplification is shown to depend primarily on the internal angle at the edge (the smaller the angle, the faster the flame) and fuel thickness, and not on other factors such as aspect ratio or cross-sectional area. Using a phenomenological argument, the edge propagation rate is correlated to the spread rate over an equivalent cylindrical fuel (the limiting shape with infinite edges) with an effective radius obtained from the geometry of the edges and the diffusion length scale of the solid phase. A formula for flame spread over cylindrical fuel from the literature is used to link the new results to existing models. Both thick and thin limits are shown to encompass the wide range of three-dimensional spread rate data within the effective radius (the independent variable), which can be determined from the known parameters. Based on these results, different types of cross-sectional areas can be sorted in the order of their inherent fire safety characteristics. 相似文献
957.
Hisayuki Nakatani Hitoshi Matsuoka Shoutarou Suzuki Toshiaki Taniike Liu Boping Minoru Terano 《Macromolecular Symposia》2007,257(1):112-121
Summary: Temperature rising elution fractionation (TREF) has been regarded as a powerful technique for study of semicrystalline polymers. In this paper, two examples of unique applications of TREF were introduced. One was the study on the influence of extraction of internal donor on the variation of isospecific active sites of a MgCl2- supported Ziegler catalyst, and the other was the estimation of the relationship between polymer micro-tacticity and degradation rate of isotactic polypropylene (iPP). The former example revealed the conversion from high to low isospecific site by the extraction of internal donors, whereas the latter showed a negative correlation between the level of isotacticity and the degradation rate. These results demonstrated that TREF was useful in these research applications. 相似文献
958.
Y. Yoshida M. Matsuoka S. C. Moon H. Mametsuka E. Suzuki M. Anpo 《Research on Chemical Intermediates》2000,26(6):567-574
The photocatalytic decomposition of liquid water on Pt-loaded TiO2 (Pt/TiO2) catalysts was investigated. The results obtained by XPS and XRD measurements of the catalysts as a function of the calcination
temperature as well as the photocatalytic decomposition reactions of H2O clearly indicate that controlling the oxidation state of Pt as well as the amount of loaded Pt species are both important
factors in the design of water-splitting photocatalysts having high efficiency and stoichiometry. 相似文献
959.
Liu Zhenlin Ohtake Hideyuki Izumida Shinji Ono Shingo Sarukura Nobuhiko 《Optical and Quantum Electronics》2000,32(4-5):521-529
The THz-radiation power from InAs reaches sub-mW level in a 1.7-T magnetic field irradiated with femtosecond laser pulses of 1.5-W average power. The THz-radiation power is related almost quadratically both to the magnetic field and to the excitation laser power. Furthermore, the THz-radiation spectrum is found to be controlled by the excitation pulsewidth, chirp direction of the excitation pulse, and the magnetic field. 相似文献
960.
T. Nakano J. K. Ahn H. Ejiri M. Fujiwara T. Hotta N. Matsuoka T. Matsumura T. Mibe M. Nomachi H. Toki C. W. Wang S. C. Wang H. Kawai T. Ooba T. Iwata Y. Miyachi T. Toyama A. Wakai K. Hicks H. Akimune Y. Asano Y. Sugaya S. Dat N. Kumagai Y. Ohashi H. Toyokawa K. Imai M. Yosoi A. Ichikawa T. Kishimoto A. Sakaguchi M. Sumihama S. Makino H. Shimizu 《Nuclear Physics A》2000,670(1-4):332-339
The GeV photon beam at SPring-8 is produced by backward-Compton scattering of laser photons from 8 GeV electrons. The maximum energy of the photon will be above 3 GeV, and the beam intensity will be 107 photons/sec. Polarization of the photon beam will be 100 % at the maximum energy with fully polarized laser photons. We report the outline of the quark nuclear physics project with this high-quality high-intensity beam. 相似文献