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81.
Hans Salié 《Mathematische Annalen》1966,165(3):196-203
Ohne Zusammenfassung
Ernst Hölder zum 65. Geburtstag 相似文献
82.
López-Martens R Varjú K Johnsson P Mauritsson J Mairesse Y Salières P Gaarde MB Schafer KJ Persson A Svanberg S Wahlström CG L'huillier A 《Physical review letters》2005,94(3):033001
We report the generation, compression, and delivery on target of ultrashort extreme-ultraviolet light pulses using external amplitude and phase control. Broadband harmonic radiation is first generated by focusing an infrared laser with a carefully chosen intensity into a gas cell containing argon atoms. The emitted light then goes through a hard aperture and a thin aluminum filter that selects a 30-eV bandwidth around a 30-eV photon energy and synchronizes all of the components, thereby enabling the formation of a train of almost Fourier-transform-limited single-cycle 170 attosecond pulses. Our experiment demonstrates a practical method for synthesizing and controlling attosecond waveforms. 相似文献
83.
Gundry S Anscombe MP Abdulla AM Sali E Tisch JW Kinsler P New GH Marangos JP 《Optics letters》2005,30(2):180-182
We demonstrate the efficient modulation of an approximately 100-femtosecond pulse in a Raman medium coherently prepared by nanosecond pulses. Raman sidebands of the ultrashort pulse spanning 360 THz are generated with an efficiency of >5%. We show that the mechanism permitting the sidebands to be generated is the preparation of a significant vibrational coherence in the medium that is robust to disturbance by an intense short pulse. If the observed sidebands were phase compensated, they would form a short train of approximately ten 3-fs pulses. Focusing would permit the realization of a peak intensity of >10(13) W cm(-2). 相似文献
84.
A. Gürtler J.J. Gilijamse A.A.R. Wetzels L.D. Noordam E. Sali M. Bellini 《Optics Communications》2007,270(2):1457-339
We propose focusing by a Fresnel zone plate into a pinhole as a cost-efficient, rugged component for wavelength selection in femtosecond pulses. We show measurements of the frequency selectivity of a Fresnel zone plate for an ultra-broadband supercontinuum pulse. We verify that our zone plate does not considerably stretch the 65 fs laser pulses in time. 相似文献
85.
Attila Sali 《Order》1985,2(2):123-127
Let P=P
1×P
2×...×P
M
be the direct product of symmetric chain orders P
1, P
2, ..., P
M
. Let F be a subset of P containing no l+1 elements which are identical in M–1 components and linearly ordered in the Mth one. Then max |F|cM
1/2lW(P), where W(P) is the cardinality of the largest level of P, and c is independent of P, M and l. Infinitely many P show that this result is best possible for every M and l apart from the constant factor c. 相似文献
86.
Ph. Balcou P. Salières K. S. Budil T. Ditmire M. D. Perry A. L'Huillier 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1995,34(2):107-110
We demonstrate that we can use the extreme ultraviolet radiation produced by high order harmonic generation to perform photoionization experiments. With harmonics from the 11th to the 69th of a 140 fs Cr:LiSAF laser operating at 825 nm, we measure the relative photoionization cross sections of xenon, krypton, argon and neon over the range 10 to 110 eV. With narrow bandwidth harmonics produced by a tunable, 1 ps dye laser, we observe the autoionizing states between the 4p
5 ionization thresholds in krypton. 相似文献
87.
A new 4-(N-methylpiperazine)-N-allyl-1,8-naphthalimide with intense yellow-green fluorescence has been synthesized. Then it has been copolymerized with styrene and methylmetacrylate. The photophysical characteristics of the fluorescent dye and its copolymers (poly(St-co-NI) and poly(MAA-co-NI)) have been determined viewing their sensor properties for protons and transition metal cations (Cu2+, Fe3+ and Zn2+). Fluorescence enhancement is the photophysical response of the 4-(N-methylpiperazine)-N-allyl-1,8-naphthalimide to the presence of metal cations and protons, while fluorescence quenching is observed for both copolymers. 相似文献
88.
Vladislav Semak Andrej Boháč Marta Sališová Gabriela Addová Peter Danko 《Chemical Papers》2008,62(3):275-280
α-Methyl-γ-butyrolactone (III) has been prepared directly from γ-butyrolactone (I) in 89 % yield by selective monomethylation conditions: K2CO3/DMC/210°C/7 h. The reaction mechanism was elucidated and described. An intermediate and two byproducts: methyl tetrahydro-3-methyl-2-oxofuran-3-carboxylate
(II), 3-(methoxycarbonyl)propyl methyl carbonate (IV) and 3-(methoxycarbonyl)butyl methyl carbonate (V) were identified. The high temperature disproportionation of K2CO3 in the presence of dimethyl carbonate to MeOK was observed. The new selective synthesis of 2-methyl-1-tetralone (VI) from α-methyl-γ-butyrolactone (III) by Friedel-Crafts conditions was performed in 79 % yield. 相似文献
89.
In this communication, we report the oxidation and reduction behavior of fluorite type solid solutions in U-Zr-O. The maximum solubility of ZrO2 in UO2 lattice could be achieved with a mild oxidizing followed by reducing conditions. The role of valency state of U is more dominating in controlling the unit cell parameters than the incorporated interstitial oxygen in the fluorite lattice. The controlled oxidation studies on U-Zr-O solid solutions led to the delineation of a new distorted fluorite lattice at the U:Zr=2:1 composition. The detailed crystal structure analysis of this ordered composition Zr0.33U0.67O2.33 (ZrU2O7) has been carried from the powder XRD data. This phase crystallizes in an orthorhombically distorted fluorite type lattice with unit cell parameters: a=5.1678(2), b=5.4848(2), c=5.5557(2) Å and V=157.47(1) Å3 (Space group: Cmcm, No. 63). The metal ions have distorted cubical polyhedra with anion similar to the fluorite structure. The excess anions are occupied in the interstitial (empty cubes) of the fluorite unit cell. The crystal structure and chemical analyses suggest approximately equal fractions of U4+ and U6+ in this compound. The details of the thermal stability as well as kinetics of formation and oxidation of ZrU2O7 are also studied using thermogravimetry. 相似文献
90.
Libor ervenka Michaela Frühbauerov Jií Palar
ík Sali Muriqi Helena Velichov 《Molecules (Basel, Switzerland)》2022,27(22)
Carob pod powder, an excellent source of health-promoting substances, has found its use in a wide range of food products. Grinding conditions affect the physical and chemical properties of the powder, but their influence on the bioaccessibility of phenolic compounds in carob pod powder has not yet been determined. The carob pods were ground for 30–180 s in a vibratory grinder. The median values (D50) of particle size decreased after 60 s of grinding (87.9 μm), then increased to 135.1 μm. Lightness showed a negative correlation with D50 and aw, while the values of redness and yellowness decreased with the reduction in particle size and water activity. The smaller the value of D50, the higher the equilibrium moisture content of carob powder. Phenolic acids (vanillic, ferulic, cinnamic) and flavonoids (luteolin, naringenin, apigenin) were found in all samples of carob powder. The grinding time influenced their content in carob powder, with maximum values at 180 s. Similar observations were made when assessing antioxidant capacity. The in vitro digestion process only improved the bioaccessibility of catechin content in all samples. However, the bioaccessibility of the phenolic compounds and the total phenolic and flavonoid contents decreased with the increase in grinding time. Our findings revealed that the grinding of carob pods for 180 s improved the extractability of phenolics; however, their bioaccessibility was reduced. It is sufficient to ground the carob pod for 30 s, ensuring good availability of nutraceuticals and lower energy cost for grinding. 相似文献