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991.
We establish two-sided estimates for the fundamental frequency (the lowest eigenvalue) of the Laplacian in an open set
with the Dirichlet boundary condition. This is done in terms of the interior capacitary radius of Ω which is defined as the
maximal possible radius of a ball B with a negligible intersection with the complement of Ω. Here negligibility of
means that cap(F)≤ γ cap (B), where cap a means the Wiener (harmonic) capacity and
is arbitrarily fixed with the sole restriction
. We provide explicit values of constants in the two-sided estimates. 相似文献
992.
993.
A. V. Anisovich V. V. Anisovich V. N. Markov M. A. Matveev A. V. Sarantsev 《Physics of Atomic Nuclei》2005,68(9):1573-1586
The Bethe-Salpeter equations for quark-antiquark composite systems with different quark masses, such as \(q\bar s(with q = u,d),q\bar Q\), and \(s\bar Q\) (with Q = c, b), are written in terms of spectral integrals. For mesons characterized by the mass M, spin J, and radial quantum number n, the equations are written for the (n, M2) trajectories with fixed J. The mixing between states with different quark spin S and angular momentum L is also discussed. 相似文献
994.
D. V. Amelin Yu. G. Gavrilov Yu. P. Gouz V. A. Dorofeev R. I. Dzhelyadin A. M. Zaitsev A. V. Zenin A. V. Ivashin I. A. Kachaev V. V. Kabachenko A. N. Karyukhin A. N. Konoplyannikov V. F. Konstantinov V. V. Kostyukhin V. D. Matveev V. I. Nikolaenko A. P. Ostankov B. F. Polyakov D. I. Ryabchikov A. A. Solodkov A. V. Solodkov O. V. Solovianov E. A. Starchenko A. B. Fenyuk Yu. A. Khokhlov 《Physics of Atomic Nuclei》2005,68(3):359-371
Experimental investigations of candidates for hybrid mesons in the VES experiment at the Institute for High Energy Physics (Protvino) are surveyed. The data in question concern π 1 (1400) characterized by the exotic quantum numbers of J PC = 1?+ and observed in the ηπ ? final state; JPC = 1?+ π 1 (1600) in the ηπ ?, b 1 (1235)π, and f 1(1285)π ? final states; and J PC = 0?+ π(1800) in the f 0(980)π ?, f 0(1300)π ?, f 0(1500)π ?, and a 0 ? (980)η final states. New results are given along with data published previously. 相似文献
995.
996.
997.
J. Alnis A. Matveev N. Kolachevsky T. Wilken R. Holzwarth T. W. Hänsch 《The European physical journal. Special topics》2008,163(1):89-94
We report on an external cavity diode laser at 972 nmstabilized to a mid-plane mounted Fabry-Perot (FP) resonator with afinesse
of 400000. The 0.5 Hz optical beat note line width betweentwo similar lasers (Allan deviation 2 × 10-15) is limitedby thermal noise properties of two independent FP resonators. Thelong term drift of the FP resonator and mirror
substrates made fromUltra-Low-Expansion glass (ULE) is small and can be well predictedon time intervals up to many hours if
the resonator is stabilized atthe zero thermal expansion temperature Tc. Using a Peltierelement in a vacuum chamber for temperature stabilization allowsstabilization of the FP cavity to Tc which is usually below theroom temperature. Beat note measurements with a femtosecond opticalfrequency comb referenced to
a H-maser during 15 hours have shown awell defined linear drift of the FP resonance frequency of about 60 mHz/s with residual
frequency excursions of less than ±20 Hz. 相似文献
998.
Sergey Ambrozevich Mark van der Auweraer Dmitry Dirin Mikhail Parshin Roman Vasil’ev Alexey Vitukhnovsky 《Journal of Russian Laser Research》2008,29(6):526-537
Experimental study of the hole mobility in polyvinylcarbazole (PVK) films doped with two kinds of nanocrystals, on bare core
CdSe and core-shell CdSe/CdS quantum dots, with concentrations ranging from 3 · 1010 to 3 · 1015 cm−3, is presented. The quantum dots investigated were made using colloidal chemistry. The hole mobility was measured using the
time-of-flight technique as a function of the applied electrical field in the range 105–106 V/cm and for temperatures from 20°C to 50°C. The transient curves, being featureless on a linear plot, show on a double logarithmic
scale a sharp inflection point indicating a dispersive carrier drift process. The recovered values of the mobility are in
the range 3 · 10−8–10−6 cm2·V−1·s−1 and their field and temperature dependences can be analyzed formally within the framework of the Gaussian disorder model
proposed by B?ssler. The energetic disorder is, within the experimental accuracy, independent of the concentration and type
of quantum dots for the CdSe quantum dots at all concentrations and for the CdS/CdSe quantum dots up to 1014 cm−3. The spatial disorder factors are very large (from 5.3 to 8.7) and do not depend in a systematic way upon the type and concentration
of quantum dots (QDs). The experiments show that the apparent mobility does not change considerably with concentration, but
it was found that the samples with CdSe/CdS quantum dots at concentrations from 1015 to 3 · 1015 cm−3 show a decreased photocurrent response. The dependence of the time-integrated transients (corresponding to the full charge
value) upon the quantum-dot concentration has been determined. Differences in total photogenerated charge for pure and doped
polymer films imply that the quantum dots of that type are the hole traps with capture times much more smaller than the transit
time and with emission times a few orders longer than the transit time. CdSe quantum dots without a shell do not seem to exhibit
the same properties as core shells and do not produce considerable changes in the charge transfer, even at a density of 1015 cm−3. 相似文献
999.
1000.