共查询到20条相似文献,搜索用时 31 毫秒
1.
E. Buixaderas V. Porokhonskyy A. Paskhin M. Savinov J. Petzelt 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,30(3):319-329
Barium sodium niobate (BNN) single crystals are studied by IR spectroscopy, time-domain THz transmission spectroscopy, HF
coaxial wave-guide technique and LF dielectric spectroscopy to cover the frequency range 102-1014 Hz in a wide temperature interval. The dielectric response parallel and perpendicular to the polar c-axis is discussed. The ferroelectric transition at T
c
= 830 K is driven by a relaxational soft mode coupled with another central-mode type relaxation which both gradually disappear
on cooling in the ferroelectric phase. Below T
i
the parameters of the expected IR active amplitudon were estimated. The low-temperature permittivity increase on cooling
for the
field direction has been explained by an incipient proper ferroelectric-ferroelastic transition driven by an IR and Raman
active B2-symmetry soft mode.
Received 24 August 2002 Published online 19 December 2002
RID="a"
ID="a"e-mail: buixader@fzu.cz 相似文献
2.
Kostakis K Mourmouris S Charalabidis D Pitsikalis M 《The European physical journal. E, Soft matter》2003,10(1):55-63
Linear polyisoprenes having dimethylamine end groups were prepared by high vacuum anionic polymerization techniques using
3-dimethylaminopropyllithium as the initiator. The amine group was reacted with 2-cholesteryl-2-oxo-1,3,2-dioxaphospholane
to provide polymer chains having end zwitterionic groups chemically connected with cholesterol. The association behavior of
these end-functionalized polymers was studied in cyclohexane by low angle laser light scattering, dynamic light scattering,
and viscometry. The aggregation numbers, N
w were found to decrease by increasing the molecular weight of the precursor polymer, due to excluded volume repulsions. The
ability of cholesterol to form liquid crystal mesophases facilitated the association process leading to higher N
w values. The hydrodynamic behavior of the aggregates was similar to that of star polymers. The dependence of the N
w values on the molecular weight of the base polymer, the polydispersity of the associates and the absence of critical micelle
concentration, cmc are compatible with the linear head-packing model.
Received 29 April 2002 and Received in final form 13 November 2002 Published online: 11 March 2003 相似文献
3.
T. Hayakawa Y. Toh M. Oshima M. Matsuda Y. Hatsukawa J. Katakura H. Iimura T. Shizuma S. Mitarai M. Sugawara H. Kusakari Y.H. Zhang 《The European Physical Journal A - Hadrons and Nuclei》2002,15(3):299-302
High-spin states of 157Dy were investigated using in-beam γ-ray spectroscopy techniques with a 150Nd(12C, 5n) reaction. Three rotational bands with the h
9/2, i
13/2 and h
11/2 configurations were observed up to (43/2-), 53/2+ and 45/2-, respectively. Interband M1 transitions in the h
11/2 (high-Ω) band were also measured up to the highest-spin state. The high-spin states were well reproduced by calculations
using the tilted-axis-cranking model (TAC). The B(M1)/B(E2) ratio, Routhian and the tilted angle of the angular-momentum vector are found to be in good agreement with the result of
the TAC calculation.
Received: 22 August 2002 / Accepted: 26 September 2002 / Published online: 19 November 2002
RID="a"
ID="a"e-mail: hayakawa@jball4.tokai.jaeri.go.jp
Communicated by W. Henning 相似文献
4.
P. Farmanara H.-H. Ritze V. Stert W. Radloff I.V. Hertel 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,19(2):193-209
Neutral ammonia clusters (NH3)m are photo-excited to the electronic state by a deep UV femtosecond laser pump pulse. Within a few hundred femtoseconds a significant fraction of the clusters
rearrange to form an H-transfer state (NH3)m-2NH4(3s)NH2 with the subunit NH4 in its 3s electronic ground state. This state is then electronically excited by a time-delayed infrared control pulse of variable wavelength.
Finally, a third (probe) pulse in the UV ionizes the clusters for detection. The lifetime of the excited (NH3)m-2NH4(3p)NH2 states is found to vary between 2.7 and 0.13 ps depending on cluster size and excitation energy. It increases drastically
upon deuteration. The corresponding cluster size-dependent photoelectron spectra allow us to disentangle the underlying energetics
of the excitation and ionization process and reveal additional processes, such as nonresonant ionization or dissociative ionization.
The experimental findings suggest that the excited H-transfer ammonia complexes with m > 2 are deactivated by an internal conversion process back to the electronically lowest H-transfer state followed by fast
dissociation.
Received 22 September 2001 and Received in final form 31 January 2002 相似文献
5.
M. Angeloni C. Aruta G. Balestrino P. Orgiani A. Tebano P.G. Medaglia 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(4):561-566
In this report we demonstrate that high quality epitaxial heterostructures, based on metallic SrRuO3 and insulating SrTiO3 individual blocks a few unit cells thick, can be grown in a purely 2D, layer-by-layer mode, using pulsed laser deposition
with in situ reflection high energy electron diffraction (RHEED) diagnostics. The thickness of each constituent block can be controlled
at the level of a single unit cell. A detailed investigation carried out at the synchrotron facility, ESRF, by various X-ray
techniques has demonstrated that each intensity oscillation of the RHEED specular spot corresponds strictly to the growth
of a single perovskite unit cell, either SrRuO3 or SrTiO3. Furthermore, we show that, in these structures, the interfaces between the different constituent blocks are very sharp with
a roughness of only one unit cell.
Received 3 July 2002 / Received in final form 12 September 2002 Published online 31 October 2002
RID="a"
ID="a"e-mail: tebano@uniroma2.it 相似文献
6.
L. Zhang W. Kleemann J. Dec R. Wang M. Itoh 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,28(2):163-171
The dielectric permittivity ε′ - i
of SrTi 18O 3 (STO18) is studied under a dc electric field E as a function of the temperature, T. In ε′
vs.
T, a double-peak is found when 0 < E < 30 KV/m. While the peak at high-T is attributed to the smeared ferroelectric phase transition, the low-T one is induced by domain wall motion. The transverse Ising model including an external homogeneous and quenched random-fields
is successfully used to describe both the smeared phase transition and the domain wall response in the low-T domain state. The calculations are in good agreement with the experimental results.
Received 4 January 2002 / Received in final form 25 March 2002 Published online 19 July 2002 相似文献
7.
J. Walls R. Ashby J.J. Clarke B. Lu W.A. van Wijngaarden 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(2):159-162
The lithium D lines were studied using a diode laser that was frequency modulated by an electro-optic modulator, to excite an atomic beam.
The transmission of part of the laser beam through an etalon was monitored to correct for the nonlinearity of the laser scan.
The results for the 6,7Li 2 S
1/2 and 2 P
1/2 hyperfine splittings agree very well with the best existing data while those for the D1 isotope shift and 6,7Li fine structure splittings disagree significantly from data obtained by a previous laser atomic beam experiment. Our result
for the D1 isotope shift is very close to the latest value computed using Hylleraas variational theory.
Received 8 April 2002 / Received in final form 26 June 2002 Published online 21 January 2003
RID="a"
ID="a"e-mail: wvw@yorku.ca 相似文献
8.
A.N. Andreyev K. Van de Vel A. Barzakh A. De Smet H. De Witte D.V. Fedorov V.N. Fedoseyev S. Franchoo M. Górska M. Huyse Z. Janas U. Köster W. Kurcewicz J. Kurpeta V.I. Mishin K. Partes A. Plochocki P. Van Duppen L. Weissman 《The European Physical Journal A - Hadrons and Nuclei》2002,14(1):63-75
Alpha-decay properties of the neutron-deficient isotope 185Pb were studied at the PSB-ISOLDE (CERN) on-line mass separator using the resonance ionisation laser ion source (RILIS). The
nuclei of interest were produced in a 1.4 GeV proton-induced spallation reaction of a uranium graphite target. In contrast
to previous studies, two α-decaying isomeric states were identified in 185Pb. The relative production of the isomers, monitored by their α-counting rates, could be significantly changed when a narrow-bandwidth
laser at the RILIS setup was used to scan through the atomic hyperfine structure. Based on the atomic hyperfine structure
measurements, along with the systematics for heavier odd-mass lead isotopes, the spin and the parity of these states were
interpreted as 3/2- and 13/2+ and their nuclear magnetic moments were deduced. The α-decay energy and half-life value for the I
π = 13/2+ isomer are E
α = 6408(5) keV, T
1/2 = 4.3(2) s, respectively; while for the I
π = 3/2- isomer ( T
1/2 = 6.3(4) s) two α-decays with E
α1 = 6288(5) keV, I
α1 = 56(2)% and E
α2 = 6486(5) keV, I
α2 = 44(2)% were observed. By observing prompt α-γ coincidences new information on the low-lying states in the daughter isotope
181Hg was obtained.
Received: 7 February 2002 / Accepted: 19 February 2002 相似文献
9.
A. Hürstel M. Rejmund E. Bouchez P.T. Greenlees K. Hauschild S. Juutinen H. Kettunen W. Korten Y. Le Coz P. Nieminen Ch. Theisen A.N. Andreyev F. Becker T. Enqvist P.M. Jones R. Julin H. Kankaanpää A. Keenan P. Kuusiniemi M. Leino A.-P. Leppänen M. Muikku J. Pakarinen P. Rahkila J. Uusitalo 《The European Physical Journal A - Hadrons and Nuclei》2002,15(3):329-334
Prompt and delayed gamma-ray spectroscopy of very neutron-deficient bismuth isotopes 187, 189Bi has been performed using the Recoil Decay Tagging (RTD) method. The isomeric i
13/2 states have been identified and their lifetimes have been measured. The systematics of these long-lived M2 isomers has been extended to the proton-unbound isotopes. The general behaviour of single-proton states is discussed within
the systematics and interpreted within the shell-model framework.
Received: 2 May 2002 / Accepted: 3 June 2002 / Published online: 19 November 2002
RID="a"
ID="a"e-mail: wkorten@cea.fr
RID="b"
ID="b"Present address: GANIL, Caen, France.
RID="c"
ID="c"Present address: Radiation and Nuclear Safety Authority, P.O. Box 14, FIN-00881 Helsinki.
Communicated by D. Schwalm 相似文献
10.
R.A. Ganeev A.I. Ryasnyansky M.K. Kodirov S.R. Kamalov V.A. Li R.I. Tugushev T. Usmanov 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,20(1):129-131
The results of third-order nonlinear susceptibilities studies of Fe- and Zn-doped polyvinylpyrrolidone (PVP) aqueous solution
in processes of third harmonic generation of Nd:YAG laser radiation are presented. Nonlinear susceptibilities of PVP:Fe and
PVP:Zn were calculated to be 5×10-13 esu and 3×10-13 esu respectively. Third harmonic conversion efficiencies in these metallocomplexes were measured to be 8×10-7 and 5×10-7 respectively. The Z-scan method was applied to determine Kerr effect influence on frequency conversion process. The value
of nonlinear refractive index of PVP:Fe at the wavelength of λ = 1064 nm was measured to be n
2 = - 6.7×10-13 esu.
Received 30 November 2001 / Received in final form 27 March 2002 Published online 28 June 2002 相似文献
11.
I. Dillmann M. Hannawald U. Köster V.N. Fedoseyev A. Wöhr B. Pfeiffer D. Fedorov J. Shergur L. Weissman W.B. Walters K.-L. Kratz 《The European Physical Journal A - Hadrons and Nuclei》2002,13(3):281-284
Production yields and β-decay half-lives (T
1/2) of very neutron-rich indium isotopes were determined at CERN/ISOLDE using isobaric selectivity of a resonance-ionization
laser ion-source. Beta-delayed neutron (βdn) multiscaling measurements have yielded improved T
1/2 for 206(6) ms 132In, 165(3) ms 133In and 141(5) ms 134In. With 92(10) ms 135In, a new r-process nuclide has been identified which acts as an important “waiting point” in the In isotopic chain for neutron
densities in the range n
n≃ 1024-1026 n/cm3, where the r-matter flow has already passed the A≃ 130 abundance peak region.
Received: 17 January 2002 / Accepted: 30 January 2002 相似文献
12.
Verneuil E Clain J Buguin A Brochard-Wyart F 《The European physical journal. E, Soft matter》2003,10(4):345-353
A soft bead (radius R
b) is pressed with a force F against a hydrophobic glass plate through a water drop (“wet” JKR set-up). We observe with a fast camera the growth of the
contact zone bridging the rubber bead to the glass. Depending on the approach velocity V, two regimes are observed : i) at large V a liquid film is squeezed at the interface and dewets by nucleation and growth of a dry contact; ii) at low velocities, the
bead remains nearly spherical. As it comes into contact, the rubber bead spreads on the glass with a characteristic time (in
the range of one millisecond) τ ≈ ηR
b
2/F, where η is the liquid viscosity. The laws of spreading are interpreted by a balance of global mechanical and viscous forces.
Received: 22 December 2002 / Accepted: 24 March 2003 / Published online: 29 April 2003
RID="a"
ID="a"e-mail: brochard@curie.fr 相似文献
13.
Lei Gao Yanyan Huang 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,33(2):165-171
The effective linear and nonlinear optical properties of metal/dielectric composite media, in which ellipsoidal metal inclusions
are distributed in shape, are investigated. The shape distribution function P(L
x, L
y) is assumed to be 2Δ-2θ(L
x - 1/3 + Δ/3)θ(L
y - 1/3 + Δ/3)θ(2/3 + Δ/3 - L
x - L
y), where θ( . . . ) is the Heaviside function, Δ is the shape variance and Li are the depolarization factors of the ellipsoidal inclusions along i-symmetric axes (i = x, y). Within the spectral representation, we adopt Maxwell-Garnett type approximation to study the effect of shape variance Δ
on the effective nonlinear optical properties. Numerical results show that both the effective linear optical absorption α
∼ ωIm() and the modulus of the effective third-order optical nonlinearity enhancement |χ(3)
e|/χ(3)
1 exhibit the nonmonotonic behavior with Δ. Moreover, with increasing Δ, the optical absorption and the nonlinearity enhancement
bands become broad, accompanied with the decrease of their peaks. The adjustment of Δ from 0 to 1 allows us to examine the
crossover behavior from no separation to large separation between optical absorption and nonlinearity enhancement peaks. As
Δ → 0, i.e., the ellipsoidal shape deviates slightly from the spherical one, the dependence of |χ(3)
e|/χ(3)
1 on Δ becomes strong first and then weak with increasing the imaginary part of inclusions' dielectric constant. In the dilute
limit, the exact formula for the effective optical nonlinearity is derived, and the present approximation characterizes the
exact results better than old mean field one does.
Received 10 December 2002 Published online 4 June 2003
RID="a"
ID="a"e-mail: lgaophys@pub.sz.jsinfo.net 相似文献
14.
D. Sohler Zs. Dombrádi J. Blomqvist J. Cederkäll J. Huijnen M. Lipoglavšek M. Palacz A. Atac C. Fahlander H. Grawe A. Johnson A. Kerek W. Klamra J. Kownacki A. Likar L.-O. Norlin J. Nyberg J. Persson D. Seweryniak G. de Angelis P. Bednarczyk D. Foltescu D. Jerrestam S. Juutinen E. Mäkelä M. de Poli H.A. Roth T. Shizuma Ö. Skeppstedt G. Sletten J. Timár S. Törmänen M. Weiszflog 《The European Physical Journal A - Hadrons and Nuclei》2003,16(2):171-175
Excited states of 99Ag were populated via the 50Cr + 58Ni (261 MeV) reaction using the NORDBALL detector array equipped with charged-particle and neutron detector systems for reaction
channel separation. On the basis of the measured γγ-coincidence relations and angular distribution ratios a significantly
extended level scheme has been constructed up to E
x ∼ 7.8 MeV and I = 35/2. The experimental results were described within the framework of the shell model. Candidates for states fully aligned
in the πg
9/2
-3ν(d
5/2, g
7/2)2 valence configuration space were found at 4109 and 6265 keV.
Received: 18 June 2002 / Accepted: 11 October 2002 / Published online: 4 February 2003
RID="a"
ID="a"e-mail: sohler@atomki.hu
Communicated by J. ?yst? 相似文献
15.
R. Ferrini G. Guizzetti M. Patrini A. Parisini L. Tarricone B. Valenti 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,27(4):449-458
In0.49Ga0.51P films, both undoped and doped n- and p-type (up to 1018 cm-3), were grown lattice matched on GaAs substrates, with different miscut angles, by Metal-Organic Vapour Phase Epitaxy (MOVPE)
at different temperatures. The shift of the fundamental gap E0, caused by “ordering effect” was measured as a function of temperature by photoluminescence. The complex refractive index
= n + ik and the dielectric function = ɛ
1 + iɛ
2 at room temperature were determined from 0.01 to 5.5 eV by using complementary data from fast-Fourier-transform far-infrared
(FFT-FIR), dispersive, and ellipsometric spectroscopies. The effect of the native oxide was accounted for and the self-consistency
of the optical functions was checked in the framework of the Kramers-Kronig causality relations. In the restrahlen region
the dielectric function was well fitted by classical Lorentz oscillators; in the transparent region below E0, the refractive index was modelled by a Sellmeier dispersion relation; in the interband region the dielectric function was
well reproduced by analytical lineshapes associated to seven critical points. Thus parametrized analytical expressions were
obtained for the optical functions all over the spectral range, without discontinuities, to be used in the modelling and characterization
of multi-layer structures, also on opaque substrates.
Received 13 December 2001 Published online 25 June 2002 相似文献
16.
H. Arkın T. Çelik 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,30(4):577-580
To investigate the performance of the energy landscape paving (ELP) procedure for peptides, we apply it here to deltorphin,
a linear heptapeptide with bulky side chains (H-Tyr1-D-Met2-Phe3-His4-Leu5-Met6-Asp7-NH2) and compare the results with the Multicanonical method (MUCA) in regard of finding the low-energy structures. Deltorphin
is modeled in vacuum by the potential energy function ECEPP.
Received 23 July 2002 / Received in final form 18 September 2002 Published online 31 December 2002 相似文献
17.
E. Alessio A. Carbone G. Castelli V. Frappietro 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,27(2):197-200
Long-range correlation properties of stochastic time series y(i) have been investigated by introducing the function σ2
MA =
[y(i) - (i)]2, where (i) is the moving average of y(i), defined as 1/n
y(i - k), n the moving average window and Nmax is the dimension of the stochastic series. It is shown that, using an appropriate computational procedure, the function σ
MA varies as nH where H is the Hurst exponent of the series. A comparison of the power-law exponents obtained using respectively the function σ
MA and the Detrended Fluctuation Analysis has been also carried out. Interesting features denoting the existence of a relationship
between the scaling properties of the noisy process and the moving average filtering technique have been evidenced.
Received 31 December 2001 相似文献
18.
A.V. Papoyan M. Auzinsh K. Bergmann 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,21(1):63-71
We report results of a theoretical and experimental study of the ground state nonlinear Hanle effect under strong laser excitation.
It is shown that besides the well-known zero-magnetic field suppression of absorption on F
g = F→F
e = F - 1 transitions caused by population trapping, an optical pumping induced enhanced absorption occurs on F
g = F→F
e = F + 1 transitions for small B-fields. The latter effect becomes more pronounced for high F values. The experiment with atomic vapor of Cs (D2 line, F
g = 4) confirms an increase of the spectrally unresolved fluorescence yield at zero magnetic field and 600 mW/cm2 laser intensity by 9% or 42%, when excitation occurs with linearly or circularly polarized light, respectively. The results
of the experiment agree with numerical simulation studies using equations of motion for a density matrix.
Received 24 November 2001 / Received in final form 25 March 2002 Published online 24 September 2002 相似文献
19.
G.A. Chass S. Lovas R.F. Murphy I.G. Csizmadia 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,20(3):481-497
An exhaustive ab initio and DFT search for energetically stable conformers from the topologically possible set was undertaken on the N-acetyl-phenylalanyl-N-methylamide
and N-acetyl-tyrosyl-N-methylamide systems. The geometries of all 81 phenylalanyl and 162 tyrosyl possible rotamers, described
under the rules outlined by Multi-Dimensional Conformational Analysis (MDCA), were attempted at each of the RHF/3-21G, RHF/6-31G(d)
and B3LYP/6-31G(d) levels of theory. A total of 32 and 66 stable conformational minima were found for the phenylalanyl and
tyrosyl amino acid diamides, respectively, at the B3LYP/6-31G(d) level. From the tyrosyl set, 33 unique conformers emerge
when the orientation of the A
i
3
dihedral angle (p-OH orientation) is disregarded. A total of 31 conformers were common to both sets and showed nearly identical geometries.
The comparison of the optimized DFT geometries of the two systems showed near by perfect linear fits with R2 values of 0.9997, 0.9994, 0.9997, and 0.9996 for the φ
i
, ψ
i
, A
i
1
, and A
i
2
dihedral angles, respectively. Relative energies of the matching 31 conformers also fitted to a linear plot with an R2 value of 0.9985. The geometric centroid of the aromatic ring in the sidechain of both systems was found to be within 4.1
?of the H and O atoms of the peptide groups, in 21 and 2 of the conformers, respectively. None of the non-matching conformers
showed any such interaction distance ≤4.1 ?.
Received 1st February 2002 / Received in final form 28 May 2002 Published online 13 September 2002 相似文献
20.
M. Sakai S. Ishiuchi M. Fujii 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,20(3):399-402
The picosecond time-resolved IR spectrum of the 7-azaindole dimer has been measured by picosecond time-resolved nonresonant
ionization detected IR spectroscopy. This new time-resolved technique was developed by combining nonresonant ionization detected
IR (NID-IR) spectroscopy with tunable picosecond IR and UV lasers. The time-resolved NID-IR spectrum from 2 600 cm-1 to 3 800 cm-1 shows a drastic change from 1.5 ps to 11 ps time evolution. A mode-specific vibrational redistribution has been suggested.
Received 14 May 2002 / Received in final form 11 June 2002 Published online 13 September 2002 相似文献