全文获取类型
收费全文 | 108篇 |
免费 | 0篇 |
专业分类
化学 | 1篇 |
物理学 | 107篇 |
出版年
2014年 | 1篇 |
2012年 | 5篇 |
2011年 | 5篇 |
2010年 | 1篇 |
2009年 | 6篇 |
2008年 | 6篇 |
2007年 | 9篇 |
2006年 | 5篇 |
2005年 | 3篇 |
2004年 | 1篇 |
2003年 | 5篇 |
2002年 | 2篇 |
2001年 | 6篇 |
2000年 | 2篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 7篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1980年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 4篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有108条查询结果,搜索用时 15 毫秒
81.
D. Habs B. M. Hegelich J. Schreiber P. G. Thirolf 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,55(2):253-264
The use is suggested of a laser-accelerated dense electron sheet with
an energy of (E=[(g)\tilde] mc2E=\tilde{\gamma} mc^2) as a relativistic mirror to reflect coherently a second
laser with photon energy ħω, generating by the Doppler boost
high-energy γ photons with $
\hbar \omega ' = 4\tilde \gamma ^2 \hbar \omega
$
\hbar \omega ' = 4\tilde \gamma ^2 \hbar \omega
and
short duration [A. Einstein, Annalen der Physik 17, 891 (1905); D. Habs et al., Appl. Phys. B 93, 349 (2008)]. Two of these counter-propagating
γ beams are focused by the parabolically shaped electron sheets into the
interaction region with small, close to diffraction-limited, spot size.
Comparing the new nγ-mγ collider with former proposed
γγ collider schemes we achieve the conversion of many
photon-pairs in a small space-time volume to matter-antimatter particles,
while in the other discussed setups only two isolated, much more
high-energetic photons will be converted, reaching in the
new approach much higher energy densities and temperatures.
With a γ-field strength somewhat below the Schwinger limit we can
reach this complete conversion of the γ bunch energy into
e+e- or quark-antiquark q[`(q)]q\bar{q}-plasmas.
For a Bose-Einstein condensate (BEC) [A. Einstein, Physikalisch-mathematische Klasse (Berlin) 22, 261 (1924); A. Einstein, Physikalisch-mathematische Klasse (Berlin) 22, 3 (1925); A. Griffin, D.W. Snoke, S. Stringari, Bose-Einstein Condensation (Cambridge University Press, 1995)] final state or for the Cooper pair ground state at higher densities [A.J. Leggett, Quantum Liquids, Oxford Graduate Texts (Oxford University Press, 2006)] the strong induced transition
into this coherent state is of special interest for single-cycle γ
pulses. Due to annihilation these cold coherent states are very
short-lived. For γ beams with photon energies
of 1–10 keV the rather cold e+e--plasma or
e+e--BEC expands to a cold dense aggregate of positronium (Ps)
atoms, where the production of Ps molecules is discussed.
For photon energies of 1–10 MeV we discuss the production of
a cold induced π0-BEC followed by the formation of molecules.
For the direct population of higher q[`(q)]q\bar{q} densities we can study
condensates of color-neutral mesons with enhanced population.
For a γγ collider with several-cycle laser pulses
the following cycles heat up the fermion-antifermion
f[`(f)]f\bar{f} system to a certain temperature.
Thus we can reach high energy densities and temperatures of an e+e-γ
plasma, where the production of hadrons in general or the quark-gluon
phase transition can be observed. Within the long-term goal of very
high photon energies of about 1 GeV in the nγ-mγ-collider,
even the electro-weak phase transition or SUSY phase transition
could be reached. 相似文献
82.
S. Ter-Avetisyan M. Schnürer T. Sokollik P. V. Nickles W. Sandner U. Stein D. Habs T. Nakamura K. Mima 《The European physical journal. Special topics》2009,169(1):117-121
The complex dynamical behavior of the electron sheath in laser driven ion acceleration leads to variations in ion beam pointing
and ion energy modulation. These processes are derived from high resolution particle spectroscopy and 2D-PIC simulations.
The phenomena arise from ion source movement if laser irradiation occurs at oblique incidence. Different laser absorption
processes act in dependence on laser parameter which determines the ion acceleration. 相似文献
83.
J. Schreiber M. Kaluza F. Grüner U. Schramm B.M. Hegelich J. Cobble M. Geissler E. Brambrink J. Fuchs P. Audebert D. Habs K. Witte 《Applied physics. B, Lasers and optics》2004,79(8):1041-1045
We report on measurements of source sizes and charge state distributions of ions accelerated from thin foils irradiated by ultrashort (100–300 fs) high-intensity (1-6×1019 W/cm2) laser pulses. The source sizes of proton and carbon ion beams originating from hydrocarbon contaminants on the surfaces of 5 m thick aluminum foils were investigated using the knife-edge method. For low-energy protons and low-carbon charge states, the source area was found to exceed the focal spot area by a factor of 104. For the determination of charge state distributions, sandwich targets consisting of a 25 m thick tungsten layer, a 2-nm thin beryllium layer, and again a tungsten layer whose thickness was varied were used. These targets were resistively heated to remove the light surface contaminants. Peaked energy spectra of oxygen and argon ions corresponding to the equilibrium distribution after propagation through matter were observed. PACS 41.75.Jv; 52.38.Kd; 52.25.Jm; 52.50.Jm; 52.70.Nc; 41.75.Ak 相似文献
84.
M. Bussmann U. Schramm D. Habs 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,45(1):129-132
We present a new cooling scheme for the preparation of highly charged ions for future in-trap precision experiments.
A plasma of laser cooled 24Mg+ ions trapped in a 3D harmonic confinement potential is used as a stopping medium for the highly charged ions.
We focus on the dynamic evolution of the plasma, determining suitable cooling conditions for fast recooling of the 24Mg+ ions.
The results of a realistic parallel simulation of the complete stopping process presented here indicate that a small, constant
detuning of the laser frequency is sufficient for subsequent recooling of the plasma, thus maintaining the stability of the
plasma. 相似文献
85.
U. Schramm M. Bussmann D. Habs M. Steck T. Kühl K. Beckert P. Beller B. Franzke F. Nolden G. Saathoff S. Reinhardt S. Karpuk 《Hyperfine Interactions》2005,162(1-4):181-188
We report on the first laser cooling of a bunched beam of multiply charged ions performed at the ESR (GSI) at a beam energy of GeV. Moderate bunching provided a force counteracting the decelerating laser force of one counterpropagating laser beam.
This versatile type of laser cooling lead to longitudinally space-charge dominated beams with an unprecedented momentum spread
of . Concerning the beam energy and charge state of the ion, the experiment depicts an important intermediate step from the established
field of laser cooling of ion beams at low energies toward the unique laser cooling scheme proposed for relativistic beams
of highly charged heavy ions at SIS 300 (FAIR).
Funded by the German BMBF under contract number 06ML183. 相似文献
86.
B. Schwartz Ch. Ender D. Habs D. Schwalm M. Dahlinger E. Kankeleit H. Folger R. S. Simon H. Backe 《Zeitschrift für Physik A Hadrons and Nuclei》1986,325(4):489-490
The ß-decay half-life of130Cd has been measured and its importance as N=82 ‘waiting-point’ nucleus for astrophysical rapid neutron capture (r?) process scenarios is discussed. 相似文献
87.
88.
89.
90.
Backe H. Baum R. -R. Fricke B. Habs D. Hellmann K. Hies M. Illgner Ch. Krameyer Ch. Kunz H. Lauth W. Martin R. Schwamb P. Theobald W. Thörle P. Trautmann N. 《Hyperfine Interactions》1996,97(1):535-541
Istope shift and hyperfine structure measurements have been performed for the242fAm fission isomer with target production rates of only a few per second. The method is based on resonance ionization spectroscopy (RIS) in a buffer gas cell with radioactive decay detection of the ionization process (RADRIS). A relative isotope shift ratioX
exp=IS242f,241/ IS243,241=41.7±0.9 has been measured for the 500.02 nm transition corresponding to a nuclear parameter 242f,241=5.4±0.3 fm2. The analysis of the quadrupole moment based on the deformed Fermi-model of the nuclear charge distribution including second order corrections results inQ
20=38.2 ±1.4(
–0.8
+0.4
)model eb. The measurement of the hyperfine structure splitting of the transition at 466.28 nm yields a negativeg-factor and a nuclear spin ofI=2 orI=3.Work supported by the Bundesministerium für Bildung und Forschung under contract 06 MZ 5661. 相似文献