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91.
92.
Shyjumon Ibrahimkutty Daniel Issenmann Stefan Schleef Anke‐Susanne Müller Yves‐Laurent Mathis Biliana Gasharova Erhart Huttel Ralph Steininger Jörg Göttlicher Tilo Baumbach Albrecht Bartels Christof Janke Anton Plech 《Journal of synchrotron radiation》2011,18(4):539-545
A high‐repetition‐rate pump–probe experiment is presented, based on the asynchronous sampling approach. The low‐α mode at the synchrotron ANKA can be used for a time resolution down to the picosecond limit for the time‐domain sampling of the coherent THz emission as well as for hard X‐ray pump–probe experiments, which probe structural dynamics in the condensed phase. It is shown that a synchronization of better than 1 ps is achieved, and examples of phonon dynamics of semiconductors are presented. 相似文献
93.
A new crystalline octahedral hexaaqua Ni(II) bis(o-tolylazo-citrazinate)hexahydrate complex was synthesized. The analytical data proved the formation of 1:2 stoichiometry. An X-ray structure investigation has been carried out. The triclinic space group is p and the unit cell parameters are a = 585.5 pm, b = 993 pm, c = 1139.4 pm, α = 101.6°, β = 97.4°, γ = 102.4°. Evaluation of intensity data revealed the structure with an R-value of 0.03 (2316 observed independent reflections). The compound consists of hexaaqua nickel(2+) ions, univalent anions of the carboxylic acid and six additional water molecules per 相似文献
94.
We propose and experimentally demonstrate a system for the generation of pulses of tunable pulse-width as those required in high spectral efficiency optically routed networks. Pulse narrowing of 500 ps pulses by 90% is accomplished through a SOA based non-linear loop mirror. Optical switching through the SOA loop mirror is used to shape and carve these large pulses (e.g., 500 ps) generated by non-expensive low-frequency optoelectronic components to narrow pulses (e.g., 50 ps). We also calculate the minimum loop size and optimum repetition rate of the original pulse train for the generation of the shorter pulse-width pulse train. 相似文献
95.
The quantal symmetry property of the CP1 nonlinear σ model with Maxwell non-Abelian ChernSimons terms in(2+1) dimension is studied.In the Coulomb gauge,the system is quantized by using the Faddeev-Senjanovic(FS) path-integral formalism.Based on the quantaum Noether theorem,the quantal conserved angular momentum is derived and the fractional spin at the quantum level in this system is presented. 相似文献
96.
V. S. Gorelik A. A. Esakov A. N. Morozov P. P. Sverbil’ S. D. Tyves 《Journal of Russian Laser Research》2008,29(1):71-89
We developed a method for detecting traces of foreign components in water and analyzing the microstructure of water. The method
is based on studies of the characteristics of secondary emission arising in aqueous media under excitation by radiation of
ultraviolet lasers and light emitting diodes. A new type of cuvette (capillary cuvettes) for studying the secondary emission
in molecular media was elaborated. The cuvettes enable the study of aqueous solutions at small concentrations of the components;
they enable one to recognize the type of molecular compound present in aqueous media, in view of the photoluminescence spectra. 相似文献
97.
V. Gh. Mirzoyan A. A. Yeghiazaryan V. N. Aghabekyan P. V. Mirzoyan 《Journal of Contemporary Physics (Armenian Academy of Sciences)》2008,43(2):67-71
X-ray diffraction on different atomic planes of an AT-cut quartz crystal is studied experimentally in the Laue geometry in case of excitation by acoustic waves at the first resonant (fundamental) frequency. Acoustic waves lead to an increase in the integral intensity of the reflection-diffracted beam. The amplification coefficients in reflection are measured in dependence on the amplitude of a.c. voltage applied to the crystal at the resonant frequency. The frontal distributions of the intensity of the beam diffracted in the reflection direction are obtained for different atomic planes. 相似文献
98.
This paper observes the parametric excitation on atom chip by measuring the trap loss when applying a parametric modulation. By modulating the current in chip wires, it modulates not only the trap frequency but also the trap position. It shows that the strongest resonance occurs when the modulation frequency equals to the trap frequency. The resonance amplitude increases exponentially with modulation depth. Because the Z-trap is an anharmonic trap, there exists energy selective excitation which would cause parametric cooling. We confirm this effect by observing the temperature of atom cloud dropping. 相似文献
99.
A. Morozov T. Heindl J. Wieser R. Krücken A. Ulrich 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,46(1):51-57
Continuous and pulsed 12 keV electron beams were used to excite nitrogen
within a gas cell at pressures ranging from 10 to 1400 hPa. The pressure
dependence of the ratio of photon fluxes for emission from vibrational
levels v'=0 and 1 of the C 3Π u state has been studied. The
results confirm the presence of a collisional excitation mechanism
populating v'=0, 1 in addition to electron impact excitation. Rate constants
of (1.27 ±0.04)×10-11 cm3s-1 [ v'=0] and
(2.68 ±0.08)×10-11 cm3s-1 [ v'=1] were measured for
C 3Π u quenching by ground state nitrogen. For electron beam
conditions relative excitation efficiencies of 1:0.59:0.22 for
vibrational levels 0, 1 and 2 were calculated. The recorded flux ratios are
compared with the predictions given by a vibrational relaxation model. 相似文献
100.
Xe-Kr laser induced collisional ionization system and experimental preparation of its initial state: Four-photon resonant excitation
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This paper proposes a novel one-colour Xe-Kr laser induced collisional ionization system. Considering the level scheme of the system, it finds that the initial state of the reaction--the four 4f levels with even J of Xe-can be prepared through method of four-photon resonant excitation by dye laser with wavelength of -440 nm. Absorption of an additional photon (the transfer laser) of the same wavelength will complete the laser induced collisional ionization process. The resonance enhanced ionization spectrum of Xe by four laser photons at -440nm is measured through time-of-flight mass spectrometry, this aims at the preparation of the initial state of the system proposed. The Stark broadening of the measured spectrum is observed and consistent with the previous study. Analysis of the measured resonance ionization spectrum implies the feasibility of -440 nm four-photon resonant excitation of the initial 4f state of the Xe Kr system proposed in this paper, which prepares for a further experiment of laser induced collisional ionization. 相似文献