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61.
In this paper, a numerical and experimental investigation of the evolution of a transmitting shock wave and its associated
primary vortex loop, which are discharged from the open end of a square cross-sectional tube, is described. The experiments
were conducted in the square tube connected to a diaphragmless shock tube and the flowfield was visualized from the axial
direction with diffusive holographic interferometry. The numerical simulations were carried out by solving the three-dimensional
Euler equations with a dispersion-controlled scheme. The numerical results were displayed in the form of interferograms to
compare them with experimental interferograms. Good agreement between the numerical and experimental results was obtained.
More detailed numerical calculations were carried out, from which the three-dimensional transition of the shock wave configuration
from an initial planar to a spherical shape and the development of the primary vortex loop from a square shaped to a three-dimensional
structure were clearly observed and interpreted.
Received 29 January 1998 / Accepted 22 May 1998 相似文献
62.
Ultrafast multi-wavelength routing by an active birefringent fiber loop filter/interleaver is proposed and demonstrated. In
the proposed active filter, the loop part consists of a birefringent optical fiber and a traveling-wave-type phase modulator.
Numerical simulation using Jones matrix analysis shows that the periodic transmission/reflection bands of the filter can be
switched by changing a phase difference between clockwise and counter clockwise components passing through the birefringent
fiber loop. Experimentally, we realize fast switching by controlling the applied voltage to the phase modulator, and 8-GHz
wavelength routing operation is achieved. 相似文献
63.
Noriaki Onodera Kenichiro Tsuji Masaki Oiwa Syunsuke Minami Masatoshi Saruwatari 《Optical Review》2009,16(1):22-25
Less than 100ps, polarization-independent switching operation of an active birefringent optical fiber loop filter using 1.3
μm control optical pulses as well as a 1.3 μm semiconductor optical amplifier (SOA) has been demonstrated. In the proposed
SOA-based active birefringent filter operating at 1.55 μm wavelength, 1.3 μm SOA is employed to control the polarization-mode
dispersion in the loop part. By injecting 1.3 μm ps gain-switched optical control pulses into the SOA, 1.5 μm input signals
can be switched from the transmission port to the reflection port with less than 100 ps rise time. 相似文献
64.
Co-Cr/Al multilayers exhibit excellent magneto-optical characteristics due to the well-defined interfaces between Co-Cr and Al layers. Consequently, these multilayers may be useful in media for perpendicular magnetic/magneto-optical two-way magnetic recording systems. 相似文献
65.
Wavelength conversion based on the cross-gain modulation (XGM) in a traveling-wave type semiconductor optical amplifier (TW-SOA) using assist light is theoretically studied. Taking into account the spatial and temporal variations of carrier density along the SOA length, the dependency of the conversion response on the assist light conditions is simulated both for co- and counter-propagating assist light schemes. 相似文献
66.
Shigeki Nakagawa Hiroki Tanaka Masahiko Naoe 《Journal of magnetism and magnetic materials》1993,120(1-3):349-352
One of the origins of perpendicular magnetic energy of Fe-Zr films may be attributed to the structural inhomogeneity of Fe-rich alloy crystallites in a Fe-Zr amorphous matrix. Fe-Ni-Zr films deposited on PEN tape substrates at about 90°C exhibited large Ku with appropriately large 4πMs suitable for flexible recording media. 相似文献
67.
68.
We used both localized and periodic calculations on a series of monovalent (Li+, Na+, K+, Rb+, Cs+) and divalent (Mg2+, Ca2+, Sr2+, Ba2+) cations to monitor their effect on the swelling of clays. The activity order obtained for the exchangeable cations among all the monovalent and divalent series studied: Ca2+ > Sr2+ > Mg2+ > Rb+ > Ba2+ > Na+ > Li+ > Cs+ > K+. We have shown that, in case of dioctahedral smectite, the hydroxyl groups play a major role in their interaction with water and other polar molecules in the presence of an interlayer cation. We studied both type of clays, with a different surface structure and with/without water using a periodic calculation. Interlayer cations and charged 2:1 clay surfaces interact strongly with polar solvents; when it is in an aqueous medium, clay expands and the phenomenon is known as crystalline swelling. The extent of swelling is controlled by a balance between relatively strong swelling forces and electrostatic forces of attraction between the negatively charged phyllosilicate layer and the positively charged interlayer cation. We have calculated the solvation energy at the first hydration shell of an exchangeable cation, but the results do not correspond directly to the experimental d-spacing values. A novel quantitative scale is proposed with the numbers generated by the relative nucleophilicity of the active cation sites in their hydrated state through Fukui functions within the helm of the hard soft acid base principle. The solvation effect thus measured show a perfect match with experiment, which proposes that the reactivity index calculation with a first hydration shell could rationalize the swelling mechanism for exchangeable cations. The conformers after electron donation or acceptance propose the swelling mechanism for monovalent and divalent cations. 相似文献
69.
Onodera N 《Journal of chemical information and computer sciences》2001,41(4):878-888
A bibliometric approach was used to survey the state-of-the-art of research in the field of chemical information and computer sciences (CICS). By examining the CA database for the articles abstracted under the subsection "Chemical information, documentation, and data processing", Journal of Chemical Information and Computer Sciences (JCICS) was identified to have been the top journal in this subsection for the last 30 years. Based on this result, CA subsections and controlled index terms given to JCICS articles were analyzed to see trends in subjects and topics in the CICS field during the last two decades. These analyses revealed that the subjects of research in CICS have diversified from traditional information science and computer applications to chemistry to "molecular information sciences". The SCISEARCH database was used to grasp interdependency between JCICS and other key journals and also the international nature of JCICS in its publications and citedness. 相似文献
70.
Naoyuki Onodera Takayuki Aoki Hiromichi Kobayashi 《Journal of computational physics》2011,230(14):5787-5805
The resolution of a numerical scheme in both physical and Fourier spaces is one of the most important requirements to calculate turbulent flows. A conservative form of the interpolated differential operator (IDO-CF) scheme is a multi-moment Eulerian scheme in which point values and integrated average values are separately defined in one cell. Since the IDO-CF scheme using high-order interpolation functions is constructed with compact stencils, the boundary conditions are able to be treated as easy as the 2nd-order finite difference method (FDM). It is unique that the first-order spatial derivative of the point value is derived from the interpolation function with 4th-order accuracy and the volume averaged value is based on the exact finite volume formulation, so that the IDO-CF scheme has higher spectral resolution than conventional FDMs with 4th-order accuracy. The computational cost to calculate the first-order spatial derivative with non-uniform grid spacing is one-third of the 4th-order FDM. For a large-eddy simulation (LES), we use the coherent structure model (CSM) in which the model coefficient is locally obtained from a turbulent structure extracted from a second invariant of the velocity gradient tensor, and the model coefficient correctly satisfies asymptotic behaviors to walls. 相似文献