Search results for "FAST"
showing 10 items of 821 documents
Ultrafast ionization and rotational dynamics of molecules in strong laser fields
2021
The investigation of ultrafast molecular dynamics is of great importance towards the understanding of a variety of natural phenomena in physical and chemical sciences. With the rapid development of femtosecond laser systems and precision detection technologies, it is possible now to visualize and steer the motion of molecules in matter as well as the ultrafast dynamics of electrons and nuclei in molecules on a microscopic timescale. When a molecule is exposed to a strong laser field, its electrons can be freed or excited, which often triggers a rapid dissociation of the system, in which the released electrons and nuclei exhibit a strong correlation, while the electronic motion on attosecond…
Amplifier similariton fiber laser with nonlinear spectral compression
2012
International audience; We propose a new concept of a fiber laser architecture supporting self-similar pulse evolution in the amplifier and nonlinear spectral pulse compression in the passive fiber. The latter process allows for transform-limited picosecond pulse generation, and improves the laser's power efficiency by preventing strong spectral filtering from being highly dissipative. Aside from laser technology, the proposed scheme opens new possibilities for studying nonlinear dynamical processes. As an example, we demonstrate a clear period-doubling route to chaos in such nonlinear laser system.
Development of ultra-fast thulium-doped fiber lasers - Prospects for 2μm-nanophotonics.
2021
Developing highly coherent pulsed sources around the 2 µm wavelengthhas been a particularly dynamic field of research in the last couples of years,due to its numerous applications. In optical telecommunication, the wavelength rangearound 2 µm is one of the most promising solutions to increase the transmission capacitypast the current technological bottleneck. In this context, passively mode-lockedfiber lasers appear as a high potential solution for cheap laser sources, due to their veryhigh coherence and intrinsic compatibility with telecommunication systems.Passively mode-locked fiber lasers at 1,55 µm and their ultrafast dynamics is oneof the specialty of the ICB laboratory, and the aim i…
Cardiovascular disease burden from ambient air pollution in Europe reassessed using novel hazard ratio functions
2019
Abstract Aims Ambient air pollution is a major health risk, leading to respiratory and cardiovascular mortality. A recent Global Exposure Mortality Model, based on an unmatched number of cohort studies in many countries, provides new hazard ratio functions, calling for re-evaluation of the disease burden. Accordingly, we estimated excess cardiovascular mortality attributed to air pollution in Europe. Methods and results The new hazard ratio functions have been combined with ambient air pollution exposure data to estimate the impacts in Europe and the 28 countries of the European Union (EU-28). The annual excess mortality rate from ambient air pollution in Europe is 790 000 [95% confidence i…
High Yield Ultrafast Intramolecular Singlet Exciton Fission in a Quinoidal Bithiophene
2015
We report the process of singlet exciton fission with high-yield upon photoexcitation of a quinoidal thiophene molecule. Efficient ultrafast triplet photogeneration and its yield are determined by photoinduced triplet-triplet absorption, flash photolysis triplet lifetime measurements, as well as by femtosecond time-resolved transient absorption and fluorescence methods. These experiments show that optically excited quinoidal bithiophene molecule undergoes ultrafast formation of the triplet-like state with the lifetime ∼57 μs. CASPT2 and RAS-SF calculations have been performed to support the experimental findings. To date, high singlet fission rates have been reported for crystalline and pol…
Application of plant extracts to improve the shelf-life, nutritional and health-related properties of ready-to-eat meat products.
2018
Plant extracts are increasingly becoming important additives in food industry due to their antimicrobial and antioxidant abilities that delay the development of off-flavors and improve the color stability in ready-to-eat (RTE) meat products. Due to their natural origin, they are excellent candidates to replace synthetic molecules, which are generally considered to have toxicological and carcinogenic effects. The efficient extraction of these antioxidant molecules from their natural sources, along with the determination of their activity in the commercialized products, have been a great challenge for researchers and food chain contributors. The objective of this review is to highlight the ap…
Einfluß der Nahrungsaufnahme auf die Magenentleerung magensaftresistenter Tabletten und Kapseln*
2008
To test the effect of food intake on gastric emptying of gastric juice-resistant drugs, emptying time of a 11 x 6 mm tablet and a 20 x 7 mm capsule was measured by means of a metal detector in 10 healthy persons (5 men and 5 women; mean age 25 [18-30] years) after fasting and after eating three main and three in-between meals. After fasting the tablets left the stomach after 78 +/- 18 min, the capsules after 60 +/- 16 min, while meal intake delayed emptying by a factor of 10 to 12 +/- 1.3 hours and 10 +/- 1.8 hours, respectively. The slightly shorter emptying time of capsules was statistically not significant. The results indicate that gastric juice-resistant tablets taken during day-time m…
Linear-non-linear digital control for dc/dc converters with fast transient response
2009
A linear-non-linear digital control for multi-module DC/DC converters that improves system stability, solves the limit-cycle problem, reduces recovery time and limits over- and under-shoots in regulated output voltage, is presented. A simulation model in Matlab-Simulink/Active-HDL mixed environment is described. Preliminary hardware tests on a single-phase step-down converter are reported. Simulation and experimental results are shown.
Microstructure of Ag2BI4(B = Ag, Cd) superionics studied by SEM, impedance spectroscopy and fractal dimension analysis
2008
Two silver ion conducting solid electrolytes, Ag2HgI4 and Ag2CdI4, representing a wide class of AgI-based halogenide superionics have been the subjects of study by means of electrical impedance spectroscopy, SEM, porosity measurements and fractal dimension analysis. Even though both materials have been obtained by the same method under strictly identical conditions they were found to exhibit certain differences at the microstructural level. Thus, by the direct measurements of porosity and density it was found that the grain boundaries are better developed in silver mercuric iodide. On the assumption that pore geometry in the materials under study displays fractal character it was shown that…
Complexation and Electronic Communication between Corannulene-Based Buckybowls and a Curved Truxene-TTF Donor
2017
Abstract: The association behavior of an electron-donating, bowl-shaped, truxene-based tetrathiafulvalene (truxTTF) with two corannulene-based fullerene fragments, C32H12 and C38H14, is investigated in several solvents. Formation of 1:1 complexes is followed by absorption titrations and complemented by density functional theory (DFT) calculations. The binding constants are in the range logKa=2.9–3.5. DFT calculations reveal that the most stable arrangement is the conformation in which the 1,3-dithiole ring of truxTTF is placed inside the concave cavity of the corannulene derivative. This arrangement is confirmed experimentally by NMR measurements, and implies that a combination of p–p and C…