全文获取类型
收费全文 | 65篇 |
免费 | 0篇 |
专业分类
化学 | 28篇 |
晶体学 | 1篇 |
数学 | 1篇 |
物理学 | 35篇 |
出版年
2021年 | 1篇 |
2013年 | 2篇 |
2009年 | 3篇 |
2008年 | 1篇 |
2007年 | 1篇 |
2006年 | 1篇 |
2005年 | 2篇 |
2004年 | 1篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1970年 | 2篇 |
1966年 | 2篇 |
排序方式: 共有65条查询结果,搜索用时 15 毫秒
11.
12.
C. D'Ambrosio W. Fuß K. L. Kompa W. E. Schmid 《Applied physics. B, Lasers and optics》1988,45(1):17-20
In the paper, polarization beam splitters are studied. Our theoretical study reveals that the coupling length and modulation period of a polarization beam splitter made from the depressed cladding fiber are shorter compared with that made from the matched fiber. Thus the former is characterized by a short interaction length. On the other hand, a polarization beam splitter made from the raised cladding fiber has a longer coupling length and a longer modulation period than those made from the matched fiber. 相似文献
13.
W. Fuß J. Göthel M. M. Ivanenko K. L. Kompa W. E. Schmid K. Witte 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1994,29(4):291-298
The small absorption is a major problem in isotopically selective IR multiphoton dissociation. Usually the radiation diverges before it is fully absorbed. To solve this problem, we have demonstrated the application of a refocusing (Herriott) multipass cell. It can generally help in laser isotope separation to use the photons more efficiently. Employing such a cell and a Q-switched CO2 laser at high repetition rate, the dissociation yield of CHCIF2 was 23 times higher than in a single pass. The number of passes used (up to 60) was more than is conventionally possible in such small cells. The increased number was permitted by making use of spherical aberration. With 18 passes, we also measured the multiphoton absorption for various wavelengths and pressures, in part separately for12CHCIF2 and13CHCIF2, and also for two-wavelength irradiation. Appropriate change of pressure or wavelength increased the absorption. But the corresponding increase of the dissociation was larger in every case. To explain this and other observations, we invoke the molecular distribution over the energy levels. 相似文献
14.
15.
Christoph. R. Gebhardt Dr. Anna Tomsic Dr. Hartmut Schröder Dr. Michael Dürr Prof. Dr. Karl L. Kompa Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(23):4162-4165
All in a ball : Neutral molecular clusters consisting of a few thousand molecules can be seen as tiny snow balls; if they are thrown fast enough onto a surface, they are able to pick up biomolecules such as insulin from that surface. Since they break down and evaporate during and after the collision, bare biomolecular ions are available for mass spectrometry after such an energetic throw.
16.
Karl L. Kompa 《Angewandte Chemie (International ed. in English)》1988,27(10):1314-1325
The structural characterization of materials and the tailoring of their properties is an important area of chemical research. A new trend in this area is the recourse to lasers both for analytical as well as preparative purposes, exploiting the fact that lasers, by virtue of their properties (sharp energy, spatial and temporal resolution etc.), offer the most precise and selective interaction of energy and matter that we know. Furthermore, photochemical syntheses and material transformations can proceed “cold” and without causing damage to surface structures. Laser chemistry finds application in thin film deposition, in the formation of surface layers, as well as in (structuring) ablation or etching, and in the initiation and enforcing of reactions at surfaces. In the present paper an introduction to these new possibilities on the general basis of molecule-surface interactions is followed by a brief characterization of lasers suitable for such purposes. Thereafter, four examples are discussed: gas phase deposition from volatile organometallic compounds with photoelectric activation at the surface or photochemical activation of the gaseous species (e.g. by employing molecular beams). In this way (noble) metal contacts can be deposited on various substrates. Instead of surface deposition, nucleation can occur in the gaseous medium, yielding highly disperse powders, e.g. of silicon carbide. Finally, an etching reaction is discussed where the laser does not act as an energy source but as an analytical instrument to provide diagnostic and mechanistic information. 相似文献
17.
T. Hornung R. Meier D. Zeidler K.-L. Kompa D. Proch M. Motzkus 《Applied physics. B, Lasers and optics》2000,71(3):277-284
This paper reports two pump–probe experiments in sodium where dynamically tailored ultrashort pulses from a Ti:Sapphire-pumped
optical parametric amplifier were employed. The first study focuses on the one-photon Na(3s→3p) transition to derive sensitive
criteria which judge the performance of a frequency-domain pulse shaper using a spatial light modulator. On the basis of the
interpretation, follow-up experiments are suggested to test their cogency. The second experiment uses coherent quantum control
by placing an appropriate phase distribution on the incident beam to enhance or cancel the transition probability in the nonresonant
two-photon process Na(3s→→5s). Ignorant of the “ideal” phase function, an evolutionary algorithm which uses a feedback derived
from the experiment performs the optimization and produces the desired bright or dark pulses within a few minutes. Attention
is given to the role of resonant 3s→3p transitions excited by the spectral wings of the pump pulse. Different parametrizations
of the phase distribution have been examined. Two of these produced solutions which had not previously been predicted by theory
still meet the objective of the experiment. The study represents the first successful application of a feedback-organized
self-learning algorithm to the design of dark pulses.
Received: 3 November 1999 / Published online: 5 July 2000 相似文献
18.
Absorption of CO2 laser pulses at different wavelengths by ground-state and vibrationally heated SF6
The absorption of CO2 laser pulses by low pressure SF6 gas has been investigated over a wide range of energy fluxes. For laser energy fluxes of 0.01–1 J cm-2 the effective absorption cross section varies between 0.2 and 2 × 10-18 cm2. For each laser line an individual dependence on the energy is found and in some cases minor changes in the absorption behaviour seem to occur around 0.1 J cm-2. SF6 excited with an average vibrational energy content of up to 20 photons/molecule does not absorb measurable amounts of 9.4 μm laser light. The influence of various SF6 and Ar pressures on the temporal shape of the transmitted pulses has been investigated. 相似文献
19.
Gollub C Korff BM Kompa KL de Vivie-Riedle R 《Physical chemistry chemical physics : PCCP》2007,9(3):369-376
In this theoretical study vibrational ladder climbing in transition metal carbonyl complexes, as a possible means to initialize chemical ground state reactions, and the resulting vibrational population distribution using chirped mid-infrared femtosecond laser pulses is investigated. Our model system is MnBr(CO)(5), a strong IR-absorber within an experimentally easily accessible wavelength region. Special emphasis is put on the perturbation due to additional vibrational modes, especially on one, which allows dissociation at low energies. The related potential energy surface for the three representative modes is calculated, whereon quantum dynamics calculations, including the laser-molecule interaction, are performed. No significant coupling could be detected, neither in the bound, nor in the dissociative region. Contrarily, we found a dynamical barrier even for energies high above the dissociation limit. Different vibrational population distributions after the laser excitation of the CO stretching mode could be generated in dependence of the chirp parameters. Based on these findings we simulated the laser excitation corresponding to an experiment by M. Joffre et al., Proc. Natl. Acad. Ssi. U. S. A., 2004, 101(36), 13216-13220, where coherent vibrational ladder climbing in carboxyhemoglobin was demonstrated and we could offer an explanation for an open question, concerning the interpretation of the spectroscopic data. 相似文献
20.
The feasibility of controlled ultrafast pumping in the mid IR and the probe of the subsequent intramolecular dynamics is illustrated for vibrational excitation of the two metal carbonyls W(CO)6 and Mn(CO)5Br in solution. Pumping and probing is performed by short, 130 fs, pulses centered at about 2000 cm−1. Frequency resolved measurements of the time delayed probe pulse are performed. Measured two dimensional spectra are fitted by a kinetic scheme that models the vibrational dynamics. Fast relaxation is solvent induced with the solvent acting also as a heat bath. The (several) probe signals in the experiment can be thought of as the response of a finite state logic machine. This suggests that the molecular machine can act as an ultrafast (petaHertz) processor. The number of internal (memory) states of the machine is determined by the number of vibrational states in the kinetic scheme that can fit the observed relaxation. The number of outputs of the machine is the number of the several different available probe signals. It is shown that the machine is massively parallel because in each (sub ps) time step it produces an entire vector as an output and that each component of the output vector is, by itself, a transform over the input. Beyond that, the machine can produce a (finite number of) different output vectors in sequential time steps. 相似文献