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1.
A. V. Glushkov I. T. Makarov M. I. Pravdin I. E. Sleptsov D. S. Gorbunov G. I. Rubtsov S. V. Troitsky 《JETP Letters》2008,87(4):190-194
A sample of 33 extensive air showers (EASs) with estimated primary energies above 2 × 1019 eV and high-quality muon data recorded by the Yakutsk EAS array is analyzed. The observed muon density is compared event-by-event
to that expected from CORSIKA simulations for primary protons and iron using SIBYLL and EPOS hadronic interaction models.
The study suggests the presence of two distinct hadronic components, “light” and “heavy.” Simulations with EPOS are in good
agreement with the expected composition in which the light component corresponds to protons and the heavy component to iron-like
nuclei. With SIBYLL, simulated muon densities for iron primaries are a factor of ∼ 1.5 less than those observed for the heavy
component for the same electromagnetic signal. Assuming a two-component proton-iron composition and the EPOS model, the fraction
of protons with energies E > 1019 eV is 0.52−0.20+0.19 at the 95% C.L.
The text was submitted by the authors in English. 相似文献
2.
E. Bill A. Gismelseed D. Laroque A. X. Trautwein H. Nasri J. Fischer R. Weiss 《Hyperfine Interactions》1988,42(1-4):881-884
The divalent high-spin iron in the P460 center of hydroxylamine oxidoreductase and in three possible “picket fence” heme models
exhibit extremely large quadrupole splittings (∼4 mms−1). Their isomer shifts of about 1 mms−1 are consistent with the X-ray results of two of the models, i.e. that Fe(II) is pentacoordinated. The coordination geometry
of iron deviates considerably from the common fourfold symmetry of the “picket fence” porphyrin due to a CH3CO
2
−
ligand. This feature is also reflected by the significant anisotropies of g-factors, A tensor and rhombicity E/D. 相似文献
3.
Spectral lines of Yb lasing in 1.03–1.05 μm region structured by 50–200 μm spots were found at focusing a pulsed LiF:F2+ color center laser of 0.5–5.0 GW/cm2 intensity on highly doped Yb:YAG or Yb:glass plates in a resonator. Small spots at the spectrograph located ≈ 1 m apart from
the resonator indicated a “sub-diffraction” directivity of Yb generation, 1–2 orders better than the diffraction limit 10−3–10−2 rad determined by the pumped volume dimensions. Observed features of Yb emission are explained assuming off-axis oscillations
in Yb laser on phase-synchronized photons due to a strong spatial-angular selection of radiation in the resonator. Propagation
of near diffraction free beams at angles to the axis built at the spectrograph slit for every 10–15 ns pulse of Yb generation
a magnified “image” of a structure of generating channels in the active medium. This image projection brought a corresponding
structure of spots in Yb spectra. It was found that channels may be formed due to a high-frequency spatial modulation (micrometers
scale) of the refractive index profile in samples caused by the oscillating amplitude of thermoelastic stresses in the pumped
medium. Obtained data demonstrate a possibility to study (with high spatial and temporal resolution) non-equilibrium stales
of materials in small volumes using laser radiation emerging from these objects. This study results evidence for the novel
concept of the spatial distribution of electromagnetic field of a photon: not in the form of a “travelling” wave but in the
form of a wave with maxima and nodes located at fixed positions along the photon propagation direction. 相似文献
4.
E. Ya. Paryev 《Physics of Atomic Nuclei》2006,69(2):332-354
Within the spectral function approach, we study the direct production and decay via the dikaon (dimuon) channel of ϕ mesons
in the interactions of 2.4-and 2.7-GeV protons with light and medium target nuclei. It is shown that the K
+
K
− (μ+ μ−) invariant-mass distribution consists of the two components, which correspond to the ϕ decay “outside” and “inside” the target nucleus. The first (narrow) component has the free ϕ width, while the second (broad) component is distorted by the nuclear matter owing to resonance-nucleon scattering and a
possible in-medium modification of the kaons and ρ meson at finite baryon density. The relative strength of the “inside” and “outside” components is analyzed in different scenarios
for the ϕ width and momentum cut. It is demonstrated that the width of the resulting dimuon invariant-mass distribution on medium nuclei
is larger than the free ϕ width by a factor of about 2 if the total ϕ in-medium width is used and the respective cutoff for the ϕ three-momentum is applied, whereas the resulting dikaon invariant-mass distribution has an insignificant sensitivity to the
ϕ in-medium properties owing to the strong absorption of the K
− in the surrounding nuclear matter. On the other hand, because of the distortion of the K
+ and K
− on their way out of the target nucleus mainly due to the hadronic kaon potentials, the latter distribution is broadened and
shifted to higher invariant masses, which means that the measurement of such broadening would give additional evidence for
the modification of the kaon and antikaon properties in the nuclear medium.
The text was submitted by the author in English. 相似文献
5.
Preparation, material characterization, ion transport and battery discharge characteristic studies are reported for a new
silver molybdate glass system: x[0.75AgI: 0.25AgCl]: (1-x)[Ag2O: MoO3], where 0<x<1 in molar weight fraction. The traditional host AgI has been replaced by an alternate compound: “a quenched
[0.75AgI: 0.25 AgCl] mixed system/solid solution”. Electrical conductivity (σ), ionic mobility (μ) and mobile ion concentration
(n) measurements were carried out as a function of “x”. The composition: 0.8[0.75AgI: 0.25AgCl]: 0.2[Ag2O: MoO3] exhibited the highest conductivity (∼ 6×10−3 S·cm−1) at room temperature and has been referred to as ‘optimum conducting composition (OCC)’. The compositional variation of “μ”
and “n” revealed that the enhancement in the room temperature conductivity of OCC is predominantly due to the increase in
mobile ion concentration. The XRD and DSC analysis on OCC indicated the formation of glassy phase with partial presence of
unreacted polycrystalline phase of the host salt. The temperature dependence of various ionic transport parameters viz. “σ”,
“μ”, “n” and ionic transference number (tion) were carried out on the OCC and the results have been discussed on the basis of theoretical models suggested for superionic
glasses. In addition to this, solid state batteries were fabricated using OCC as electrolyte and discharge characteristics
were studied under varying load conditions. 相似文献
6.
Accurate conductivity measurements as a function of hydrostatic pressure (1 – 5000 bars) and temperature (20 – 150 °C) have
been performed on a cationic inorganic glass and a cationic conducting polymer.
In both cases, the conductivity decreases with increasing pressure and the variation of Inσ at constant temperature as a function
of pressure gives straight lines with slopes which allow an “activation volume”, ΔV*, to be obtained by the relationship (∂lnσ/∂P)T=− (ΔV*/RT). In the case of silver metaphosphate glass, studied below its glass transition temperature, the activation volume
(5 cm3⋅mol−1) is temperature independent and equal to the molar volume of the silver cation. Since the transport mechanism implies a free
energy barrier, this volume is a real activation volume, corresponding to the difference in volume between a mole of the moving
species in its activated transition state and its volume at normal equilibrium.
In the case of the sodium conductive polymer, studied above its glass transition temperature, the previous thermodynamic definition
does not hold any more because the ionic transport follows a V.T.F. behaviour rather than an Arrhenius law. Consequently,
ΔV* is an “apparent activation volume” without a simple physical meaning. Experimental values are higher (20 to 30 cm3⋅mol−1) and decrease with temperature. In this polymer, the mobility of the charge carriers is interpreted in terms of free volume
mechanism. From the variations of the apparent activation volume with temperature, the critical free volume Vf* for an elementary displacement is estimated. For the Na+ conductive ionomer Vf* is estimated to be equal to 13 cm3⋅mol−1. This large value would indicate the participation of macromolecular chain segments in the ionic transport.
Paper presented at the 5th Euroconference on Solid State Ionics, Benalmádena, Spain, Sept. 13–20, 1998. 相似文献
7.
G. Di Francia V. La Ferrara P. Maddalena D. Ninno L. P. Odierna V. Cataudella 《Il Nuovo Cimento D》1996,18(10):1187-1196
Summary In this paper we report on the frequency dependence of the AC conductivity of porous silicon in the range 10 Hz-100 kHz. Two
types of testing devices have been fabricated on three different series of samples formed electrochemically using as a starting
materialptype,n
−-type andn
+-type silicon substrates. For frequencies less than 20-40 kHz the conductivity is found to follow a sublinear frequency dependence.
This behaviour is typical of a carrier transport mechanism determined by an anomalous diffusion process. At higher frequencies
we find that surface states influence the transport mechanism. This suggests a double-channel transport mechanism: one related
to porous-silicon “volume” properties and the other more connected to the “surface” itself.
Paper presented at the III INSEL (Incontro Nazionale sul Silicio Emettiore di Luce) Torino, 12–13 October 1995. 相似文献
8.
Acoustic relaxation in undeformed and plastically deformed CsI single crystal has been studied using the composite oscillator
technique at frequencies (1–7) × 105 Hz in the temperature range 2–15 K. Plastic deformation leads to appearance of an internal friction peak localized in the
temperature interval 4–5 K. It is shown that the peak shifts towards higher temperatures when increasing the vibration frequency
and corresponds to a thermally activated relaxation process with very low values of the activation energyU ≈ 1.9×10−3 eV and the attack frequencyν
0≈6.7 × 103 s−1. Interaction of sound with dislocation kinks migrating in the second order Peierls relief is considered as a possible mechanism
of the peak.
Research was made possible in part by Grants U9T000 and U9T200 from the International Science Foundation and supported in
part by the Fundamental Research Foundation of Ukraine (Project 2.4/156 “Bion”). 相似文献
9.
Gold electrodes with known contact geometries were studied using impedance spectroscopy. From these data it was possible to
determine the specific polarisation conductivity per unit length of three-phase boundary (TPB). The values were found to be
(3÷22)×10−4 S·cm−1 dependent on the electrode history in pure oxygen at 977 °C and 2×10−6 S·cm−1 at 977 °C in “pure” hydrogen (PO2=10−20 atm at 1001 °C). The results are compared with previous data obtained for platinum electrodes. 相似文献
10.
Pt electrodes with defined contact geometries were studied by using impedance spectroscopy. The specific polarisation conductivity
per unit length of the three-phase boundary was determined. It is found to be 1 × 10−4 S·cm−1 at 977 °C in an atmosphere of “pure” hydrogen with an oxygen partial pressure of 10−20 atm at 1000 °C. Investigations carried out in an atmosphere of pure oxygen revealed a pronounced dependence of the polarisation
conductivity on the electrode history. The polarisation conductivity was found to be in a range of 2 × 10−4 to 6.5 × 10−4 S·cm−1 at a temperature of 977 °C. It was possible to estimate the area of the electrolyte surface which takes part in the electrode
reaction. The real exchange current density was determined. 相似文献
11.
P. Leifer 《Foundations of Physics》1997,27(2):261-285
The ordinary quantum theory points out that general relativity (GR) is negligible for spatial distances up to the Planck scale
lP=(hG/c3)1/2∼10−33cm. Consistency in the foundations of the quantum theory requires a “soft” spacetime structure of the GR at essentially longer
length. However, for some reasons this appears to be not enough. A new framework (“superrelativity”) for the desirable generalization
of the foundation of quantum theory is proposed. A generalized nonlinear Klein-Gordon equation has been derived in order to
shape a stable wave packet. 相似文献
12.
M. B. Agranat S. I. Anisimov S. I. Ashitkov A. V. Kirillin P. S. Kondratenko A. V. Kostanovskii V. E. Fortov 《Journal of Experimental and Theoretical Physics》1998,86(6):1184-1190
A new technique for testing long-range order in high-absorption anisotropic crystals has been developed using conversion of
an incident p-(s-)wave to an s-(p-)wave due to optical anisotropy. The technique yields time-resolved measurements of parameters related to phase transformations
in thin (10−6–10−5 cm) layers with a high resolution (10−12 s). Using picosecond laser pulses and an “Agat” streak camera, the technique has been applied to an experimental investigation
of melting and recrystallization kinetics at zinc and graphite surfaces. It was found that the process of melting takes less
than 3 ps and the recrystallization time is about 100 ps.
Zh. éksp. Teor. Fiz. 113, 2162–2173 (June 1998) 相似文献
13.
A. A. Klochikhin S. A. Permogorov A. N. Reznitskii T. Breitkopf R. Westphäling C. Klingshirn 《Physics of the Solid State》1998,40(5):821-822
It is shown that, with strong pulsed excitation, the intensity of the exciton recombination band in the fluctuation tail of
the density of states in the limit of large times in the presence of traps is described by the asymptote of a solution to
the diffusion equation. The critical diffusion index corresponds to a “normal” process in the CdS-Se solid solution and to
“anomalous” diffusion in the case of ZnSe-Te.
Fiz. Tverd. Tela (St. Petersburg) 40, 892–893 (May 1998) 相似文献
14.
I. A. Denisov A. G. Selivanov K. V. Yumashev A. V. Anan’ev L. V. Maksimov N. V. Ovcharenko V. N. Bogdanov A. A. Lipovskii A. N. Vlasova 《Journal of Applied Spectroscopy》2007,74(6):866-871
We have studied the nonlinearity of the refractive index at a wavelength of 1.08 μm for optical lead silicate and lead phosphate
tellurite glasses of different compositions. We have shown that the nonlinear refractive index n2 increases as the lead content increases in lead silicate glasses and as the tellurium content increases in lead phosphate
tellurite glasses, where the latter are typically have higher values of n2, as high as 24·10−13 cgs units (47·10−16 cm2/W), and lower Rayleigh losses. We have established a correlation between the nonlinear refractive index and the microstructure
of the studied glasses. The highly nonlinear glasses are distinguished by extensive fluctuations in the heavy metal oxide
concentration which are “frozen” during cooling of the glass melt.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 6, pp. 780–784, November–December, 2007. 相似文献
15.
Zhuan Su Kangyu Chen Yuan Guo Haiping Qi Xiao-Feng Yang Minglei Zhao 《Journal of fluorescence》2010,20(4):851-856
A coumarin-based fluorescent chemosensor 1 for Zn2+ was designed and synthesized. Compound 1 exhibits lower background fluorescence due to intramolecular photoinduced electron transfer. However, upon mixing with Zn2+ in 30% (v/v) aqueous ethanol, a “turn-on” fluorescence emission is observed. The fluorescence emission increases linearly with Zn2+ concentration in the range 0.5–10 μmol L−1 with a detection limit of 0.29 μmol L−1. No remarkable emission enhancement was, however, observed for other metal ions. The proposed chemosensor was applied to
the determination of Zn2+ in water samples with satisfactory results. 相似文献
16.
Gravitational radiation arising during the formation of a protoneutron star is studied. Here it is mainly large-scale nonuniformities
that develop inside the star. The entropy and density profiles of such nonuniformities resemble the “mushroom cloud” of a
nuclear explosion. A bubble of hot neutron matter floats to the surface of the star, like the “mushroom cloud” of an explosion
in the earth’s atmosphere. Depending on the symmetry of the problem, from two to six bubbles can float upward at the same
time. The characteristic masses of such bubbles are 0.01M
⊗ and the radial velocities reach ∼0.1c. The energy radiated in the form of gravitational waves in one cycle of bubbles floating to the surface is ∼10−2
M
⊗
c
2−10−10
M
⊗
c
2. Such cycles occur repeatedly as the neutron star cools. This phase can last up to seconds. The total energy radiated in
the form of gravitational radiation can reach 10−1
M
⊗
c
2.
Pis’ma Zh. éksp. Teor. Fiz. 64, No. 12, 817–822 (25 December 1996) 相似文献
17.
Shaolin Liao Ronald J. Vernon 《International Journal of Infrared and Millimeter Waves》2007,28(6):479-490
The newly developed Taylor-Interpolation-FFT (TI-FFT) algorithm dramatically increases the computational speeds for millimeter
wave propagation from a planar (cylindrical) surface onto a “quasi-planar” (“quasi-cylindrical”) surface. Two different scenarios
are considered in this article: the planar TI-FFT is for the computation of the wave propagation from a plane onto a “quasi-planar” surface and the cylindrical TI-FFT is for the computation of wave propagation from a cylindrical surface onto a “quasi-cylindrical” surface. Due to the
use of the FFT, the TI-FFT algorithm has a computational complexity of O(N
2 log2
N
2) for an N × N computational grid, instead of N
4 for the direct integration method. The TI-FFT algorithm has a low sampling rate according to the Nyquist sampling theorem.
The algorithm has accuracy down to −80 dB and it works particularly well for narrow-band fields and “quasi-planar” (“quasi-cylindrical”)
surfaces. 相似文献
18.
A. V. Bazhenov V. V. Kveder A. A. Maksimov I. I. Tartakovskii R. A. Oganyan Yu. A. Ossipyan A. I. Shalynin 《Journal of Experimental and Theoretical Physics》1998,86(5):1030-1034
Raman light scattering and IR absorption spectra of samples containing multilayer carbon nanotubes in different stages of
purification by the selective oxidation technique have been investigated. It was found that the Raman spectra of carbon nanotubes
exhibit softening of the mode at 1582 cm−1 corresponding to E
2g
vibrations of graphite hexagons and a line at 120 cm−1 due to the radial vibrations of nanotubes. In IR absorption spectra measured in the region of 0.07–0.3 eV, several sets of
lines with a spacing of 15 meV (120 cm−1) between lines of each group have been detected. We suggest that each group corresponds to electron transitions generating
electron-hole pairs in semiconducting nanotubes and contains a phononless 00-line and its phonon replicas with spacing between
them equal to the “breathing” mode energy of 120 cm−1. Measurements of electric conductivity at a frequency of 9300 MHz indicate that, in addition to semiconducting nanotubes,
the samples contain nanotubes with properties of a highly disordered semimetal.
Zh. éksp. Teor. Fiz. 113, 1883–1891 (May 1998) 相似文献
19.
D. I. Diakonov 《JETP Letters》2009,90(6):407-411
We suggest to classify baryon resonances as single-quark states in a mean field, and/or as its collective excitations. Identifying
the Roper resonance N(1440, 1/2+), the nucleon resonance N(1535, 1/2−), and the singlet hyperon Λ(1405, 1/2−) as single-quark excitations, we find that there must be an exotic S = +1 baryon resonance Θ+ (the “pentaquark”) with a mass about 1440 + 1535 − 1405 = 1570 MeV and spin-parity 1/2+. We argue that Θ+ is an analog of the Gamov-Teller excitation long known in nuclear physics. 相似文献
20.
G. Gabrielse W. Jhe D. Phillips W. Quint C. Tseng L. Haarsma K. Abdullah J. Gröbner H. Kalinowsky 《Hyperfine Interactions》1993,76(1):81-93
The possibility to produce, trap and study antihydrogen atoms rests upon the recent availability of extremely cold antiprotons
in a Penning trap. Over the last five years, our TRAP Collaboration has slowed, cooled and stored antiprotons at energies
1010 lower than was previously possible. The storage time exceeds 3.4 months despite the extremely low energy, which corresponds
to 4.2 K in temperature units. The first example of measurements which become possible with extremely cold antiprotons is
a comparison of the antiproton inertial masses which shows they are the same to a fractional accuracy of 4×10−8. (This is 1000 times more accurate than previous comparisons and large additional increases in accuracy are anticipated.)
To increase the number of trapped antiprotons available for antihydrogen production, we have demonstrated that we can accumulate
or “stack” antiprotons cooled from successive pulsed injections into our trap. 相似文献