共查询到20条相似文献,搜索用时 31 毫秒
1.
Timo Seppäläinen 《Communications in Mathematical Physics》2002,229(1):141-182
We study central limit theorems for a totally asymmetric, one-dimensional interacting random system. The models we work with
are the Aldous–Diaconis–Hammersley process and the related stick model. The A-D-H process represents a particle configuration
on the line, or a 1-dimensional interface on the plane which moves in one fixed direction through random local jumps. The
stick model is the process of local slopes of the A-D-H process, and has a conserved quantity. The results describe the fluctuations
of these systems around the deterministic evolution to which the random system converges under hydrodynamic scaling. We look
at diffusive fluctuations, by which we mean fluctuations on the scale of the classical central limit theorem. In the scaling
limit these fluctuations obey deterministic equations with random initial conditions given by the initial fluctuations. Of
particular interest is the effect
of macroscopic shocks, which play a dominant role because dynamical noise is suppressed on the scale we are working.
Received: 4 October 2001 / Accepted: 12 March 2002 相似文献
2.
S.-J. Ding V. Zaporojtchenko J. Kruse J. Zekonyte F. Faupel 《Applied Physics A: Materials Science & Processing》2003,76(5):851-856
The interfacial bonding and mixing between evaporated aluminum and a vapor deposited Teflon AF (abbreviated to AF) film have
been investigated with X-ray photoelectron spectroscopy. Graphite carbon (C–C), and aluminum carbide (Al–C), oxide (Al–O–C)
and fluoride (Al–F) are formed when aluminum atoms are deposited on to the AF film. With increasing deposition of aluminum,
the concentrations of these newly formed components increase gradually. Moreover, in situ annealing results in remarkable
increases in the C–C, Al–C, Al–O–C and Al–F configurations and a decrease in metallic aluminum. No significant diffusion of
aluminum into the AF film was observed during the annealing. The Al compounds form a layer at the Al/AF interface that acts
as an adhesion promoter and diffusion barrier.
Received: 21 October 2002 / Accepted: 22 October 2002 / Published online: 15 January 2003
RID="*"
ID="*"Corresponding author. Fax: +49-431/880-6229, E-mail: sjding@yahoo.com 相似文献
3.
The design and development of a molecular system functioning as a prototype of a Brownian motor is presented. The road towards
the molecular motor is illustrated with previous attempts preparing other mechanical devices, such as a molecular brake and
a molecular ratchet. Thermal and chemical energy are used to achieve unidirectional rotation in the Brownian motor. The similarities
of synthetic molecular devices with biological – microscopic – and mechanical – macroscopic – systems and the perils of extrapolating
macroscopic principles to the molecular level are also discussed.
Received: 15 November 2001 / Accepted: 14 January 2002 / Published online: 22 April 2002 相似文献
4.
Silicon nanowires grown from Au-coated Si substrate 总被引:1,自引:0,他引:1
Xing Y.J. Yu D.P. Xi Z.H. Xue Z.Q. 《Applied Physics A: Materials Science & Processing》2003,76(4):551-553
Amorphous Si nanowires were grown on an Au-coated Si substrate by heat treatment at 1000 °C under an H2 atmosphere. The nanowires have a length of several tens of a micron and a diameter of 10–20 nm. The growth mechanism of the
nanowires was investigated and explained with a solid–liquid–solid model.
Received: 11 July 2002 / Accepted: 7 July 2002 / Published online: 4 December 2002
RID="*"
ID="*"Corresponding author. Fax: +86/10-62751615, E-mail: yudp@pku.edu.cn 相似文献
5.
Z.J. Li X.L. Chen L. Dai H.J. Li H.W. Liu H.J. Gao Y.P. Xu 《Applied Physics A: Materials Science & Processing》2003,76(1):115-118
A new form of GaN nanomaterial (nanotweezers) has been obtained by chemical vapor deposition on an etched cubic MgO (100)
plane. The nanotweezers consist of a bottom rod and two arms. The bottom rods have diameters of about 100–150 nm and lengths
of about 200–500 nm, on which two arms grow out. The bottoms of the arms are about 40–70 nm and the tops are about 15–30 nm
in diameter, and 0.8–1.5 μm in length. X-ray and electron diffractions indicate the nanotweezers are zinc blende gallium nitride.
We infer that the fabrication of the GaN nanotweezers is associated with small convex hillocks on the surface of the etched
cubic MgO (100) single-crystal substrates and that the nanotweezers grow by a growth mechanism that is similar to vapor-phase
heteroepitaxy.
Received: 23 April 2002 / Accepted: 25 April 2002 / Published online: 10 September 2002
RID="*"
ID="*"Corresponding author. Fax: +86-10/8264-9531, E-mail: xlchen@aphy.iphy.ac.cn 相似文献
6.
We present a real-time investigation of ultra-fast carrier dynamics in single-wall carbon nanotube bundles using femtosecond
time-resolved photoelectron spectroscopy. The experiments allow us to study the processes governing the sub-picosecond and
the picosecond dynamics of non-equilibrium charge carriers. On the sub-picosecond time scale the dynamics are dominated by
ultra-fast electron–electron scattering processes, which lead to internal thermalization of the laser-excited electron gas.
We find that quasiparticle lifetimes decrease strongly as a function of their energy up to 2.38 eV above the Fermi level –
the highest energy studied experimentally. The subsequent cooling of the laser-heated electron gas to the lattice temperature
by electron–phonon interaction occurs on the picosecond time scale and allows us to determine the electron–phonon mass-enhancement
parameter λ. The latter is found to be over an order of magnitude smaller if compared, for example, with that of a good conductor
such as copper.
Received: 4 March 2002 / Accepted: 7 March 2002 / Published online: 3 June 2002 相似文献
7.
C. Moreau E. Therssen P. Desgroux J.F. Pauwels A. Chapput M. Barj 《Applied physics. B, Lasers and optics》2003,76(5):597-602
The potential of Laser Induced Fluorescence detection of the CH radical using C–X (0–0) excitation is investigated in a sooting
methane/air diffusion flame at atmospheric pressure. Fluorescence is detected using the very narrow (<0.4 nm) Q-branch of
the C–X (0–0) band, which enables the measurement of CH in sooting flames without interference from PAH fluorescence and soot
emissions. Absolute concentrations are obtained using Cavity Ring Down Spectroscopy. 1D CH profiles in the sooting zone are
recorded using a CCD camera with an excellent signal-to-noise ratio. The C–X (0–0) excitation associated with Q-branch detection
is shown to be three times more efficient than the B–X scheme.
Received: 4 March 2002 / Revised version: 5 November 2002 / Published online: 5 May 2003
RID="*"
ID="*"Corresponding author. Fax: +33-3/2033-6463, E-mail: eric.therssen@univ-lille1.fr 相似文献
8.
In the Ni–W system, a uniform amorphous Ni–W phase was obtained by ion irradiation of the nano-sized Ni–W multilayers at liquid-nitrogen
temperature. Interestingly, before undergoing complete amorphization, fractal patterns were observed at a relatively low irradiation
dose (3×1014 Xe+/cm2), and the patterns were characterized to consist of crystalline grains of Ni-enriched solid solution. The fractal dimension
was measured to be about 1.68±0.05, which was very close to that expected by the cluster diffusion-limited aggregation model.
Received: 30 January 2002 / Accepted: 2 February 2002 / Published online: 3 May 2002 相似文献
9.
It is shown theoretically that electromagnetically induced transparency (EIT) due to strong exciton–phonon coupling can occur
in strongly coupled exciton–phonon systems such as polymers and organic semiconductors and lead to ultra-slow light effects.
The results indicate that the strong coupling of excitons and phonons is important, but the exciton– exciton interaction plays
a small role in the generation of the EIT. Numerical results for polydiacetylene–toluene sulfonate are also presented. This
EIT in a solid-state medium might be utilized for efficient multiwave mixing and quantum nondemolition measurements, as well
as for novel acousto-optical devices.
Received: 21 August 2002 / Published online: 20 December 2002
RID="*"
ID="*"Corresponding author. E-mail: zhukadi@yahoo.com 相似文献
10.
11.
In this paper the transport of quantum particles in time-dependent random media is studied. In the white noise limit, a quantum
model for collisions is obtained. At the level of Wigner equation, this limit is described by a linear Wigner-Boltzmann equation.
AMS subject classifications: 35Q40, 35S10, 81Q99, 81V99
á Fredo. Frédéric Poupaud deceased October 13th 2004.
This research was partially supported by the EU financed network IHP-HPRN-CT-2002-00282 and by MCYT (Spain), Proyecto BFM2002–00831. 相似文献
12.
We consider a spatially periodic inviscid random forced Burgers equation in arbitrary dimension and the random time-dependent
Lagrangian system related to it. We construct a unique stationary distribution for ``viscosity' solutions of the Burgers
equation. We also show that with probability 1 there exists a unique minimizing trajectory for the random Lagrangian system
which generates a non-trivial ergodic invariant measure for the non-random skew-product extension of the Lagrangian system.
Received: 25 March 2002 / Accepted: 30 July 2002 Published online: 22 November 2002 相似文献
13.
We report on the first layer growth of a Mn6+-doped material. Large-size BaSO4 substrates of 10×6×4 mm3 were grown from a LiCl solvent by the flux method. Flat surfaces of undoped BaSO4 were then achieved by use of liquid-phase epitaxy (LPE) from a CsCl–KCl–NaCl solvent. Finally, BaSO4:Mn6+ layers were grown by LPE with growth velocities of approximately 3 μm h-1, at temperatures of 550–508 °C. Absorption, luminescence, luminescence-excitation and luminescence-decay measurements confirmed
the incorporation of manganese solely in its hexavalent oxidation state. This material possesses potential as a near-infrared
tunable laser with a wavelength range larger than Ti:sapphire.
Received: 7 January 2002 / Revised version: 30 March 2002 / Published online: 8 August 2002 相似文献
14.
F. Jegerlehner K. Kołodziej 《The European Physical Journal C - Particles and Fields》2002,23(3):463-469
We accomplish our efforts to obtain predictions for all four–fermion final states of –annihilation and the corresponding bremsstrahlung reactions which are possible in the framework of the Standard Model. For
this purpose we have developed a program ee4
. Our predictions are valid for fermions of arbitrary masses and we can obtain results for total cross sections without any
collinear cut. Keeping exact fermion masses is of course required for top quark production. We give a detailed phenomenological
analysis of fermion mass effects and real photon radiation for all channels of four–fermion production at LEP-II and next
linear collider energies.
Received: 2 October 2001 / Revised version: 2 January 2002 / Published online: 1 March 2002 相似文献
15.
J. Békési S. Szatmári P. Simon G. Marowsky 《Applied physics. B, Lasers and optics》2002,75(4-5):521-524
Applying the combination of a solid-state Ti:Sa laser system and a newly developed wide-aperture, discharge-pumped KrF amplifier,
output pulses with over 9 W average power at 300 Hz have been achieved in a single output beam. The frequency-tripled seed
pulses of the Ti:Sa system – delivering approximately 10 μJ energy at 248 nm – were amplified to over 30 mJ using a 3-pass
off-axis amplification scheme. The optical set-up has been fitted to the amplifier’s parameters, and stored-energy measurements
were carried out with different parameters in order to optimize the operational conditions of the device for the highest average
power.
Received: 10 June 2002 / Published online: 25 September 2002
RID="*"
ID="*"Corresponding author. Fax: +49-551/503-599, E-mail: jbekesi@llg.gwdg.de 相似文献
16.
D. Sabourdy V. Kermène A. Desfarges-Berthelemot M. Vampouille A. Barthélémy 《Applied physics. B, Lasers and optics》2002,75(4-5):503-507
The coherent combining of two Nd:YAG lasers using a Vernier–Michelson-type cavity has been demonstrated. The spectral behaviour
and the energetic performance are reported. We firstly show that the combining efficiency is not strongly spoilt by the gain
imbalance between the two amplifying media, and secondly, that despite the interferometric nature of the cavity, the Vernier–Michelson
laser can withstand environmental perturbations without alteration in output power.
Received: 25 April 2002 / Revised version: 18 May 2002 / Published online: 25 September 2002
RID="*"
ID="*"Corresponding author. Fax: +33-5/5545-7253, E-mail: kermene@ircom.unilim.fr 相似文献
17.
J.M.R. Parrondo B.J. de Cisneros 《Applied Physics A: Materials Science & Processing》2002,75(2):179-191
We review the literature on the energetics of Brownian motors, distinguishing between forced ratchets, chemical motors – driven
out of equilibrium by differences of chemical potential, and thermal motors – driven by temperature differences. The discussion
is focused on the definition of efficiency and the compatibility between the models and the laws of thermodynamics.
Received: 13 November 2001 / Accepted: 10 January 2002 / Published online: 22 April 2002 相似文献
18.
A.A. Bichl J.M. Grimstrup H. Grosse E. Kraus L. Popp M. Schweda R. Wulkenhaar 《The European Physical Journal C - Particles and Fields》2002,24(1):165-176
We show that the non-commutative Yang–Mills field forms an irreducible representation of the (undeformed) Lie algebra of
rigid translations, rotations and dilatations. The non-commutative Yang–Mills action is invariant under combined conformal
transformations of the Yang–Mills field and of the non-commutativity parameter . The Seiberg–Witten differential equation results from a covariant splitting of the combined conformal transformations and
can be computed as the missing piece to complete a covariant conformal transformation to an invariance of the action.
Received: 6 November 2001 / Published online: 5 April 2002 相似文献
19.
Boron nitride (BN) nanotubes have been synthesized by evaporating a mixture of boron and gallium oxide in the presence of
ammonia gas. The synthesized BN nanotubes exhibit a well-crystallized concentric structure with diameters less than 30 nm,
and no carbon contamination or defects could be observed, while the BN nanotubes with large diameters usually show a number
of defects. Some BN nanohorn structures could also be observed in the product. The carbon-free growth of BN nanotubes was
explained based on the vapor–liquid–solid growth mechanism, and the catalytic activity of liquid gallium for BN one-dimensional
growth was also demonstrated.
Received: 16 April 2002 / Accepted: 25 May 2002 / Published online: 19 July 2002 相似文献
20.
Quantum Spheres and Projective Spaces as Graph Algebras 总被引:5,自引:0,他引:5
The C
*
-algebras of continuous functions on quantum spheres, quantum real projective spaces, and quantum complex projective spaces
are realized as Cuntz-Krieger algebras corresponding to suitable directed graphs. Structural results about these quantum spaces,
especially about their ideals and K-theory, are then derived from the general theory of graph algebras. It is shown that the quantum even and odd dimensional
spheres are produced by repeated application of a quantum double suspension to two points and the circle, respectively.
Received: 31 January 2001 / Accepted: 29 July 2002 Published online: 7 November 2002
RID="*"
ID="*" Supported by grant No. R04–2001–000–00117–0 from the Korea Science & Engineering Foundation.
RID="**"
ID="**" Partially supported by the Research Management Committee of the University of Newcastle. 相似文献