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1.
L. Palladino A. Reale G. Taglieri D. Batani S. Bollanti P. Di Lazzaro F. Flora T. Letardi G. Schina M. Belli A. Scafati 《Il Nuovo Cimento D》1993,15(8):1133-1146
Summary We present a detailed study of XUV and soft X-ray emission from Cu plasma produced by an excimer laser at intensitiesI
L≦8·1011 W/cm2. The XeCl excimer laser (ψ≈308 nm) delivers pulses with energyE
L≈2.3 J, temporal durationt
L≈100 ns and brightnessB≧1014 W/cm2 sr. We recorded a spectral conversion efficiency η=0.5% eV−1 forI
L=4·1011W/cm2 in the aluminium window at 73eV with a harder X-ray tail around ≈400eV. We also measured the dependence of X-ray signal on
laser intensity and viewing angle. Experimental results have been compared with some analytical laser-plasma interaction models. 相似文献
2.
W. Hartig 《Applied Physics A: Materials Science & Processing》1978,15(4):427-432
Using the 4d- and 5s-states of sodium, two different types of two-photon resonance enhanced four-wave mixing have been observed. In the first
type 2v
L =v
IR +v
pIR radiation near 2.34 μm and UV radiation near 320 nm has been detected. In the second typev
P
−v
S
=v
L
+v
IR the UV radiation produced in the first parametric process acted as a pump for stimulated electronic Raman scattering via
the 4p-state of sodium. Resonantly enhanced by the two-photon transition 3s–4s, radiation near 1.18 μm was produced in this scheme. The realisation of a tunable coherent IR source based on these four-wave
mixing processes is discussed. 相似文献
3.
W. J. Kossler X. H. Yu A. Greer H. E. Schone C. E. Stronach M. Davis R. S. Cary J. E. Crow W. F. Lankford J. Oostens 《Hyperfine Interactions》1991,63(1-4):81-86
Transverse and zero-field μSR measurements were made on YBa2(Cu1−xNix)3O7−y withx=0.1 and 0.2, and YBa2(Cu1−x
Zn
x
)3O7−y
withx=0.03, 0.06, 0.1, and 0.16, wherey≈0.1. Since doping may lead to magnetic ordering this was searched for with both zero and transverse field μSR, but no evidence
was found over the temperature range studied: 10–100 K. However, depolarization rates as functions of temperature were obtained,
and the low temperature values of these are σ=3.2 μs−1.1.6μs−1, and 1 μs−1 forx=0.01, and 0.2 Ni, respectively, and σ=0.8 μs−1, 0.75 μs−1, 0.65 μs−1, and 0.4 μs−1 forx=0.03, 0.06, 0.1, and 0.16 Zn, respectively. Estimates for the effect of decreasing electron concentration for Zn are made,
but these alone do not account for the drop in σ. Estimates for the effect of scattering on λ and hence σ are made. The reduction
in σ for Ni dopant is in surprisingly good agreement with these estimates. For Zn the order of magnitude is correct, but the
relative lack of further change in σ after the effect of the first 0.03 addition seems to imply a saturation of the effect
of scattering. 相似文献
4.
International comparisons of I2 stabilized ion lasers operated at 514.5 nm have shown a laser frequency reproducibility of 2·10−10
v to 5·10−12
v. These results encouraged the international acceptance of the wavelength value λvac=514.673467 for thea
3 hyperfine component of the127I2 line 43-0P(13). 相似文献
5.
S. A. Buiko S. M. Kulikov V. N. Novikov S. A. Sukharev 《Journal of Experimental and Theoretical Physics》1999,89(6):1051-1054
Stimulated Brillouin scattering (STBS) and phase conjugation of CO2 laser radiation have been demonstrated experimentally for the first time in compressed xenon (59 atm at 21°C) located inside
the low-Q cavity of this laser. The nonlinear medium was exposed to the action of counterpropagating focused multimode radiation
beams. The difference between the frequencies of the longitudinal cavity modes was set at the frequency of the acoustic wave
(v
s=32.2±0.3 MHz) excited as a result of STBS by 9.584 μm radiation. The duration of the radiation pulse τ
L was close to the acoustic phonon lifetime (τ
L<τ
ph≈3× 10−6s). The excitation of STBS was manifested experimentally as the locking of longitudinal modes, an increase in power and energy,
and also an increase in the duration of the lasing pulse and a reduction in the divergence to the diffraction limit.
Zh. éksp. Teor. Fiz. 116, 1941–1946 (December 1999) 相似文献
6.
M. Bryushinin V. Golubev Y. Kumzerov D. Kurdyukov I. Sokolov 《Applied physics. B, Lasers and optics》2009,95(3):489-495
We report an experimental investigation of the non-steady-state photoelectromotive force in nanostructured GaN within porous
glass and polypyrrole within chrysotile asbestos. The samples are illuminated by an oscillating interference pattern created
by two coherent light beams and the alternating current is detected as a response of the material. Dependences of the signal
amplitude versus temporal and spatial frequencies, light intensity, and temperature are studied for two wavelengths λ=442 and 532 nm. The conductivity of the GaN composite is measured: σ=(1.1–1.6)×10−10 Ω−1 cm−1 (λ=442 nm, I
0=0.045–0.19 W/cm2, T=293 K) and σ=(3.5–4.6)×10−10 Ω−1 cm−1 (λ=532 nm, I
0=2.3 W/cm2, T=249–388 K). The diffusion length of photocarriers in polypyrrole nanowires is also estimated: L
D=0.18 μm. 相似文献
7.
M.?Silies H.?Witte S.?Linden J.?Kutzner I.?Uschmann E.?F?rster H.?Zacharias 《Applied Physics A: Materials Science & Processing》2009,96(1):59-67
The interaction of ultrashort laser pulses with solid state targets is studied concerning the production of short X-ray pulses
with photon energies up to about 10 keV. The influence of various parameters such as pulse energy, repetition rate of the
laser system, focusing conditions, the application of prepulses, and the chirp of the laser pulses on the efficiency of this
highly nonlinear process is examined. In order to increase the X-ray flux, the laser pulse energy is increased by a 2nd multipass
amplifier from 750 μJ to 5 mJ. By applying up to 4 mJ of the pulse energy a X-ray flux of 4×1010 Fe K
α
photons/s or 2.75×1010 Cu K
α
photons/s are generated. The energy conversion efficiency is therefore calculated to η
Fe≈1.4×10−5 and η
Cu≈1.0×10−5. The X-ray source size is determined to 15×25 μm2. By focusing the produced X-rays using a toroidally bent crystal a quasi-monochromatic X-ray point source with a diameter
of 56 μm×70μm is produced containing ≈104 Fe K
α1 photons/s which permits the investigation of lattice dynamics on a picosecond or even sub-picosecond time scale. The lattice
movement of a GaAs(111) crystal is shown as a typical application. 相似文献
8.
Guang S. He Yiping Cui Paras N. Prasad 《Journal of Experimental and Theoretical Physics》1997,85(5):850-856
The spectral structure of backward stimulated scattering from a 10 cm-long CS2-liquid cell is investigated by using Q-switched 10-ns and 532-nm laser pulses with different spectral linewidths. Under a narrow spectral line (∼0.1 cm−1) pump condition, very strong sharp lines near the pump wavelength (λ
0) position and the first-order stimulated Raman scattering (λ
s1) position can be observed. However, under a wide line (≈1 cm−1) pump condition, only a strong and superbroadening spectral band can be observed mainly in the red-shift side of the pump
wavelength. The different spectral features under these two conditions can be explained by a competition between stimulated
Brillouin, Raman, and Rayleigh-Kerr scattering. Under both pump conditions, the broadening spectral distributions are not
consistent with the predictions given by stimulated Rayleigh-wing scattering theories, but can be interpreted well utilizing
the theoretical model of stimulated Rayleigh-Kerr scattering.
Zh. éksp. Teor. Fiz. 112, 1563–1573 (November 1997)
Published in English in the original Russian journal. Reproduced here with stylistic changes by the Translation Editor. 相似文献
9.
FePS3 is a layered antiferromagnet (T
N=123 K) with a marked Ising anisotropy in magnetic properties. The anisotropy arises from the combined effect of the trigonal
distortion from octahedral symmetry and spin-orbit coupling on the orbitally degenerate5
T
2g
ground state of the Fe2+ ion. The anisotropic paramagnetic susceptibilities are interpreted in terms of the zero field Hamiltonian, ℋ=Σi [δ(L
iz
2
−2)+|λ|L
i
.S
i
]−Σ
ij
J
ij
S
i
.S
j
. The crystal field trigonal distortion parameter Δ, the spin-orbit coupling λ and the isotropic Heisenberg exchange,J
ij, were evaluated from an analysis of the high temperature paramagnetic susceptibility data using the Correlated Effective
Field (CEF) theory for many-body magnetism developed by Lines. Good agreement with experiment were obtained for Δ/k=215.5 K; λ/k=166.5 K;J
nn
k=27.7 K; andJ
nnn
k=−2.3 K. Using these values of the crystal field and exchange parameters the CEF predicts aT
N=122 K for FePS3, which is remarkably close to the observed value of theT
N. The accuracy of the CEF approximation was also ascertained by comparing the calculated susceptibilities in the CEF with
the experimental susceptibility for the isotropic Heisenberg layered antiferromagnet MnPS3, for which the high temperature series expansion susceptibility is available. 相似文献
10.
Principles and applications are described for a form of Doppler-free optical double resonance spectroscopy which uses amplitude
modulation sidebands (v
L
±v) imposed on a single laser frequency (v
L
). The sidebands are generated by passing the carrier radiationv
L
through an electro-optic modulator, driven at a radiofrequency ν, which enables the intensity and polarization characteristics
of the emerging radiation to be varied for enhancement of selected double-resonance processes. The technique has been applied
to infrared-infrared double-resonance studies of the Stark effects of a variety of molecules—13CH3F,12CH3F, PH3,15NH3, GeH4, SiH4, and CH3D—for which physical results are presented and discussed. These results include determination of extremely small electric
dipole moments (10−3–10−5 debye) for GeH4 and CH3D and, for the dipole moment of PH3, a vibrational state dependence which is extremely small (Δμ=0.0028(5) debye for ∣Δv
2∣=1) and a rotational state dependence which is of an unexpected sign. The spectra recorded in some cases display unusual
polarization and optical saturation effects which deviate markedly from the predictions of a simple three-wave polarization
theory. 相似文献
11.
The relative differences δ
ns
(n=1, 2, 3) of the spindependent conversion coefficients were measured for α-Fe and α=Fe2O3. In contrast to theoretical predictions of δ1s≃−10−5 we found δ1s≃−1.0(4)x10−2 for both α-Fe and α-Fe2O3. As a possible source for this difference we consider a dynamic coupling with the atomic spin during the conversion process. 相似文献
12.
Swapna Ray Jain 《International Journal of Theoretical Physics》1996,35(5):903-909
Conserved quantities and the multi-Hamiltonian structure for the integrable coupled kdv system which is associated with the
isospectral flow [(∑
i=0
N−1
ε
i
λ
i
)∂2 + ∑
i=0
N−l
V
1λ
i
]φ=λ
N
φ are deduced by the Drienfeld-Sokolov formalism. 相似文献
13.
A. A. Zhukov M. R. Trunin A. T. Sokolov N. N. Kolesnikov 《Journal of Experimental and Theoretical Physics》1997,85(6):1211-1217
The real part R
s and the imaginary part X
s of the surface impedance Z
s=R
s+ iX
s of Tl2Ba2CaCu2O8−δ
and YBa2Cu3O6.95 single crystals have been measured with high precision at frequency ω/2π=9.4 GHz in the temperature range 0<T<140 K. In the Tl2Ba2CaCu2O8−δ
crystal a linear temperature dependence R
s(T) has been found for T⩽50 K, and the magnetic field penetration depth λ(4.2 K)=X
s(4.2 K)/ω μ
0≈3760 Å has been measured. Along with well known features of the function Z
s(T) in high-quality YBa2Cu3O6.95 single crystals, such as the linearity of λ(T) and R
s(T) for T<T
c/3 and a maximum of R
s(T) at T∼T
c/2, the linearity range of λ(T) extends to T≃50 K, and this curve has a plateau in the range 60<T<85 K. The curve of R
s(T) in both the superconducting and normal states of YBa2Cu3O6.95 is well described by a two-fluid model with the electron-phonon mechanism of quasiparticle relaxation. A formula describing
the curve of λ
2(0)/λ
2(T) throughout the studied temperature range is also given.
Zh. éksp. Teor. Fiz. 112, 2210–2222 (December 1997) 相似文献
14.
Feoktistov N. A. Sakharov V. I. Serenkov I. T. Tolmachev V. A. Korkin I. V. Aleksenskii A. E. Vul’ A. Ya. Golubev V. G. 《Technical Physics》2011,56(5):718-724
The aerosol deposition of detonation nanodiamonds (DNDs) on a silicon substrate is comprehensively studied, and the possibility
of subsequent growth of nanocrystalline diamond films and isolated particles on substrates coated with DNDs is demonstrated.
It is shown that a change in the deposition time and the weight concentration of DNDs in a suspension in the range 0.001–1%
results in a change in the shape of DND agglomerates and their number per unit substrate surface area N
s
from 108 to 1011 cm−2. Submicron isolated diamond particles are grown on a substrate coated with DND agglomerates at N
s
≈ 108 cm−2 using microwave plasma-enhanced chemical vapor deposition. At N
s
≈ 1010 cm−2, thin (∼100 nm) nanodiamond films with a root-mean-square surface roughness less than 15 nm are grown. 相似文献
15.
Martin M. Block Loyal Durand 《The European Physical Journal C - Particles and Fields》2011,71(11):1806
We recently derived a very accurate and fast new algorithm for numerically inverting the Laplace transforms needed to obtain
gluon distributions from the proton structure function F2gp(x,Q2)F_{2}^{\gamma p}(x,Q^{2}). We numerically inverted the function g(s), s being the variable in Laplace space, to G(v), where v is the variable in ordinary space. We have since discovered that the algorithm does not work if g(s)→0 less rapidly than 1/s as s→∞, e.g., as 1/s
β
for 0<β<1. In this note, we derive a new numerical algorithm for such cases, which holds for all positive and non-integer negative
values of β. The new algorithm is exact if the original function G(v) is given by the product of a power v
β−1 and a polynomial in v. We test the algorithm numerically for very small positive β, β=10−6 obtaining numerical results that imitate the Dirac delta function δ(v). We also devolve the published MSTW2008LO gluon distribution at virtuality Q
2=5 GeV2 down to the lower virtuality Q
2=1.69 GeV2. For devolution, β is negative, giving rise to inverse Laplace transforms that are distributions and not proper functions. This requires us
to introduce the concept of Hadamard Finite Part integrals, which we discuss in detail. 相似文献
16.
Yu. P. Snitovskii 《Technical Physics》2009,54(6):907-911
A near-electrode nonuniform magnetic field crossed with an electric field is found to strongly affect the rate of etching
of silicon dioxide on glass substrates in a CF4 + O2 plasma when the Larmor frequency (≈109 s−1) is much higher than the frequency of collisions of an electron with surrounding plasma particles (≈106 s−1) and the frequency of the applied rf electric field (≈107 s−1). The confinement of electrons by the magnetic field in the immediate vicinity of the substrate surface to be treated increases
the rate of generation of chemically active particles, which increases the etching rate of silicon dioxide. 相似文献
17.
F. Kottmann W. Amir F. Biraben C. A. N. Conde S. Dhawan T. W. Hänsch F. J. Hartmann V. W. Hughes O. Huot P. Indelicato L. Julien P. Knowles S. Kazamias Y.-W. Liu F. Mulhauser F. Nez R. Pohl P. Rabinowitz J. M. F. dos Santos L. A. Schaller H. Schneuwly W. Schott D. Taqqu J. F. C. A. Veloso 《Hyperfine Interactions》2001,138(1-4):55-60
A measurement of the 2S Lamb shift in muonic hydrogen (μ−p) is being prepared at the Paul Scherrer Institute (PSI). The goal of the experiment is to measure the energy difference
ΔE(25
P
3/2−23
S
1/2) by laser spectroscopy (λ≈6μm) to a precision of 30 ppm and to deduce the root mean square (rms) proton charge radius with
10−3 relative accuracy, 20 times more precise than presently known.
An important prerequisite to this experiment is the availability of long-lived μp2S
-atoms. A 2S-lifetime of ∼1 μs – sufficiently long to perform the laser experiment – at H2 gas pressures of 1–2 hPa was deduced from recent measurements of the collisional 2S-quenching rate. A new low-energy negative muon beam yields an order of magnitude more muon stops in a small low-density gas
volume than a conventional cloud muon beam. A stack of ultra-thin carbon foils is the key element of a fast detector for keV-muons.
The development of a 2 keV X-ray detector and a 3-stage laser system providing 0.5 mJ laser pulses at 6 μm is on the way.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
18.
CAI Lingcang CHEN Qifeng GU Yunjun ZHANG Ying ZHOU Xianming & JING Fuqian Laboratory for Shock Wave Detonation Physics Research Institute of Fluid Physics Mianyang China 《中国科学G辑(英文版)》2005,48(6):695-705
Helium, hydrogen, and their isotopes are the simplest monoatomic and diatomic molecules. It is relatively easy to describe their properties using the basic principles of quantum mechanics. In condensed matter physics, hydrogen and helium serve as the models for the condensed matter properties at extreme conditions so that both experi- mental and theoretical physicists pay much attention to the study of their properties[1], especially the insulator-metal transition of hydrogen[2]. The aim to st… 相似文献
19.
The rare t-quark decays t → cl
j
+
l
k
−
and t → cṽ
j
k
k
induced by scalar-leptoquark doublets are considered within the minimal model involving four-color quark-lepton symmetry
and the Higgs mechanism of quark and lepton mass splitting. The partial widths with respect to the decays being considered
and the total widths Γ(t → cl
+′l
−) = Σj,k Γ(t → cl
j
+
l
k
−
) and Γ(t → cl
+′l
−) = Σj,kΓ(t → cṽ
j
v
k
) with respect to, respectively, the charged leptonic and neutrino modes are calculated. It is shown that, at scalar-leptoquark
masses higher than the t-quark mass (m
S > m
t), the branching ratios for these modes are Br(t → cl
+′l
−) ≈ (3.5−0.4) × 10−5 and Br(t → cṽ′v) ≈ (7.1−0.8) × 10−5 at m
s
= 180–250 GeV and an appropriate value of the leptoquark-mixing angle (sin β ≈ 0.2) and can increase for m
S < m
t to Br(t → cl
+′l
−) ≈ 0.03−0.002 and Br(t → cl
+′l
−) ≈ 0.46−0.05 for the charged mode at m
S
= 150–170 GeV for sin β ≈ 1 and sin β ≈ 0.2, respectively. In the cases being considered, t-quark decays to pairs of charged leptons can be accessible to detection at LHC. In the last case, these decays could manifest
themselves (for example, in dilepton events) at the Tevatron as well.
Original Russian Text ? P.Yu. Popov, A.D. Smirnov, 2006, published in Yadernaya Fizika, 2006, Vol. 69, No. 6, pp. 1006–1016. 相似文献
20.
Dephasing in open quantum chaotic systems has been investigated in the limit of large system sizes to the Fermi wavelength
ratio, L/λF 〉 1. The weak localization correction g
wl to the conductance for a quantum dot coupled to (i) an external closed dot and (ii) a dephasing voltage probe is calculated
in the semiclassical approximation. In addition to the universal algebraic suppression g
wl ∝ (1 + τD/τϕ)−1 with the dwell time τD through the cavity and the dephasing rate τ
ϕ
−1
, we find an exponential suppression of weak localization by a factor of ∝ exp[−
/τϕ], where
is the system-dependent parameter. In the dephasing probe model,
coincides with the Ehrenfest time,
∝ ln[L/λF], for both perfectly and partially transparent dot-lead couplings. In contrast, when dephasing occurs due to the coupling
to an external dot,
∝ ln[L/ξ] depends on the correlation length ξ of the coupling potential instead of λF.
The text was submitted by the authors in English. 相似文献