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971.
We report on the reflectance of blue bronze crystals in the visible frequency range as a function of temperature. The observed large oscillations in the reflectance at all wavelengths at temperatures near the Peierls transition are interpreted as interference effects stemming from a surface layer. It is found that the surface layer, which appears to be tied to fluctuations, can be as much as 1.6 microns thick. 相似文献
972.
The author of the comment objects to the characterization and the interpretation of magnetoresistance (MR) effects observed by us in La1−xCaxMnO3 (0≤x<0.4) samples. In this reply, arguments are used to show that the samples' characterization and explanation of the MR by considering the role of the short-charge ordering (CO) regions and magnetic domains are reasonable and acceptable. 相似文献
973.
Starting with the unification hypothesis of mixings of quarks and leptons and small quark-like mixings at the see-saw scale,
we find that two large mixings for νe —νx03BC; andv
μ—v
τ at the weak scale are obtained as a result of renormalization group evolution and radiative magnification if the three neutrinos
are quasi degenerate in masses and possess the same CP parity. We also find thatU
e3
remains small and well within the CHOOZ-Palo Verde bound since the correspondingV
ub
for CKM mixing is very small. Several testable pedictions are pointed out. 相似文献
974.
We consider a new model for passive mode locking in a semiconductor laser comprising a set of delay differential equations. Bifurcations leading to the appearance and break-up of the mode-locking regime are studied numerically. 相似文献
975.
976.
The radical anion of aceneazulenedione in which a benzoquinone is fused to an azulene moiety was generated by electrolysis and by reduction with the alkali metals in ethereal solvents. The hyperfine data could not be reproduced by standard Hückel calculations which usually give reliable predictions for the spin distribution in radical ions such as azulene quinones and a variety of extended π systems. However, PPP and, preferably,ab initio geometry optimisations followed by single-point calculations of the Fermi contact interaction with density functional theory, led to a straightforward assignment of the hyperfine coupling constants. 相似文献
977.
P. Bunton M. Binkley G. Asbury 《Applied Physics A: Materials Science & Processing》1997,65(4-5):411-417
Received: 21 May 1997/Accepted: 4 July 1997 相似文献
978.
Results of numerical calculations of the flow in a double-diaphragm shock tube with a tailored contact surface are reported.
The calculations were carried out using a model of an ideal shock tube allowing for the real properties of the driver gas
at high pressures and equilibrium thermodynamics of the processes behind the shock waves at Mach numbers M
s1 of the shock wave in the working gas varying in the range 5–25. Flow regimes with a tailored contact surface were obtained
for Mach numbers M
s1=6.3, 11, and 15 using the double-diaphragm shock tube at the Ioffe Physicotechnical Institute. Under these conditions, the
parameters of the working gas were kept constant for more than 1 ms. The calculated data were compared with the experimental
results and it was shown that the calculated data may be used to determine the section lengths in a double-diaphragm shock
tube and to estimate its operating time. The calculated values of the initial pressure in the sections of the tube were substantially
lower than those achieved experimentally. Measurements were made of the static pressure along the axis of a conical nozzle
during the expansion of hydrogen (initial temperature T
0=293 K) and shock-heated nitrogen (T
0=4000 K). It is found that the expansion of hydrogen is accompanied by deactivation of the rotational degrees of freedom,
and that partial freezing of the vibrational degrees of freedom takes place in the nitrogen stream.
Zh. Tekh. Fiz. 67, 88–95 (November 1997) 相似文献
979.
We calculate one-loop radiative QCD corrections to the three polarized and unpolarized structure functions that determine the beam-quark polar angle dependence of the longitudinal polarization of light and heavy quarks produced in e+e?-annihilations. We present analytical and numerical results for the longitudinal polarization and its polar angle dependence. We discuss in some detail the zero-mass limit of our results and the role of the anomalous spin-flip contributions to the polarization observables in the zero-mass limit. Our discussion includes transverse and longitudinal beam polarization effects. 相似文献
980.
We investigate numerically the interaction between two light beams, initially monochromatic, during the excitation of solitary waves in quadratically non-linear media. We show that the result of the interaction is strongly dependent on soliton oscillations occurring during excitation, generating a new class of threshold phenomena. 相似文献