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91.
92.
F. Farchioni P. Hofmann K. Jansen I. Montvay G. Münster E.E. Scholz L. Scorzato A. Shindler N. Ukita C. Urbach U. Wenger I. Wetzorke 《The European Physical Journal C - Particles and Fields》2006,47(2):453-472
Discretisation errors in two-flavour lattice QCD with Wilson quarks and DBW2 gauge action are investigated by comparing numerical
simulation data at two values of the bare gauge coupling. Both non-zero- and zero-twisted-mass values are considered. The
results, including also data from simulations using the Wilson plaquette gauge action, are compared to next-to-leading order
chiral perturbation theory formulas. 相似文献
93.
In this paper the main focus is on a stability concept for solutions of a linear complementarity problem. A solution of such
a problem is robust if it is stable against slight perturbations of the data of the problem. Relations are investigated between
the robustness, the nondegenerateness and the isolatedness of solutions. It turns out that an isolated nondegenerate solution
is robust and also that a robust nondegenerate solution is isolated. Since the class of linear complementarity problems with
only robust solutions or only nondegenerate solutions is not an open set, attention is paid to Garcia's classG
n
of linear complementarity problems. The nondegenerate problems inG
n
form an open set. 相似文献
94.
Franziska Gruber Martin Schulz‐Dobrick Dr. Martin Jansen Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(5):1464-1469
Crystallization of [Ag14(C?CtBu)12Cl][BF4] and different polyoxometalates in organic solvents yields a series of new intercluster compounds: [Ag14(C?CtBu)12Cl(CH3CN)]2[W6O19] ( 1 ), (nBu4N)[Ag14(C?CtBu)12Cl(CH3CN)]2[PW12O40] ( 2 ), and [Ag14(C?CtBu)12Cl]2[Ag14(C?CtBu)12Cl(CH3CN)]2[SiMo12O40] ( 3 ). Applying the same technique to a system starting from polymeric {[Ag3(C?CtBu)2][BF4]?0.6 H2O}n and the polyoxometalate (nBu4N)2[W6O19] results in the formation of [Ag14(C?CtBu)12(CH3CN)2][W6O19] ( 4 ). Here, the Ag14 cluster is generated from polymeric {[Ag3(C?CtBu)2][BF4]?0.6 H2O}n during crystallization. In a similar way, [Ag15(C?CtBu)12(CH3CN)5][PW12O40] ( 5 ) has been obtained from {[Ag3(C?CtBu)2][BF4]?0.6 H2O}n and (nBu4N)3[PW12O40]. The use of charged building blocks was intentional, because at these conditions the contribution of long‐range Coulomb interactions would benefit most from full periodicity of the intercluster compound, thus favoring formation of well‐crystalline materials. The latter has been achieved, indeed. However, as a most conspicuous feature, equally charged species aggregate, which demonstrates that the short‐range interactions between the “surfaces” of the clusters represent the more powerful structure direction forces than the long‐range Coulomb bonding. This observation is of significant importance for understanding the mechanisms underlying self‐organization of monodisperse and structurally well‐defined particles of nanometer size. 相似文献
95.
Several fluorine containing polycyclic aromatic hydrocarbons with exact carbon atom topology of the C60 fullerene have been synthesized. Different numbers of fluorine atoms were introduced in the key positions, as needed for an efficient intramolecular condensation to the fullerene molecule. The polycyclic aromatic compounds obtained represent attractive precursors for rational, high-yield fullerene synthesis by flash vacuum pyrolysis. 相似文献
96.
The correlation energy in the direct random phase approximation (dRPA) can be written, among other possibilities, either in terms of the interaction strength averaged correlation density matrix, or in terms of the coupled cluster doubles amplitudes obtained in the direct ring approximation (drCCD). Although the corresponding dRPA correlation density matrix on the one hand, and the drCCD amplitude matrix on the other hand, differ significantly, they yield identical energies. Similarly, the analogous RPA and rCCD correlation energies calculated from antisymmetrized two-electron integrals are identical to each other despite very different underlying working equations. In the present communication, a direct correspondence between amplitudes and densities is established and investigated with perturbation theory arguments. Our analysis also sheds some light on the properties of recently proposed RPA/rCCD variants which use antisymmetrized integrals in part of the equations and nonantisymmetrized integrals in others. 相似文献
97.
98.
Stutzki F Jansen F Eidam T Steinmetz A Jauregui C Limpert J Tünnermann A 《Optics letters》2011,36(5):689-691
Ytterbium-doped large-pitch fibers with very large mode areas are investigated in a high-power fiber amplifier configuration. An average output power of 294?W is demonstrated, while maintaining robust single-mode operation with a mode field diameter of 62?μm. Compared to previous active large-mode area designs, the threshold of mode instabilities is increased by a factor of about 3. 相似文献
99.
Stutzki F Otto HJ Jansen F Gaida C Jauregui C Limpert J Tünnermann A 《Optics letters》2011,36(23):4572-4574
A high-speed mode analysis technique is required to gain fundamental understanding of mode instabilities in high-power fiber laser systems. In this work a technique, purely based on the intensity profile of the beam, is demonstrated to be ideally suited to analyze fiber laser dynamics. This technique, together with a high-speed camera, has been applied to the study of the temporal dynamics of mode instabilities at high average powers with up to 20,000 frames per second. These measurements confirm that energy transfer between the fluctuating transversal modes takes place in millisecond-time-scale. 相似文献
100.
Jansen K van der Steen AF van Beusekom HM Oosterhuis JW van Soest G 《Optics letters》2011,36(5):597-599
We demonstrate intravascular photoacoustic imaging of human coronary atherosclerotic plaque. The data was obtained from two fresh human coronary arteries ex vivo, showing different stages of disease. A 1.25?mm diameter intravascular imaging catheter was built, comprising an angle-polished optical fiber adjacent to a 30?MHz ultrasound transducer. Specific photoacoustic imaging of lipid content, a key factor in vulnerable plaques that may lead to myocardial infarction, is achieved by spectroscopic imaging at different wavelengths between 1180 and 1230?nm. Simultaneous imaging with intravascular ultrasound was performed. 相似文献