19 research outputs found

    Sensitivity of nonlinear photoionization to resonance substructure in collective excitation

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    Collective behaviour is a characteristic feature in many-body systems, important for developments in fields such as magnetism, superconductivity, photonics and electronics. Recently, there has been increasing interest in the optically nonlinear response of collective excitations. Here we demonstrate how the nonlinear interaction of a many-body system with intense XUV radiation can be used as an effective probe for characterizing otherwise unresolved features of its collective response. Resonant photoionization of atomic xenon was chosen as a case study. The excellent agreement between experiment and theory strongly supports the prediction that two distinct poles underlie the giant dipole resonance. Our results pave the way towards a deeper understanding of collective behaviour in atoms, molecules and solid-state systems using nonlinear spectroscopic techniques enabled by modern short-wavelength light sources

    Two-electron processes in multiple ionization under strong soft-x-ray radiation

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    In a combined experimental and theoretical study we have investigated the ionization of atomic argon upon irradiation with intense soft-x-ray pulses of 105 eV photon energy from the free-electron laser FLASH. The measured ion yields show charge states up to Ar7+. The comparison with the theoretical study of the underlying photoionization dynamics highlights the importance of excited states in general and of processes governed by electron correlation in particular, namely, ionization with excitation and shake-off, processes usually inaccessible by measurements of ionic yields only. The Ar7+ yield shows a clear deviation from the predictions of the commonly used model of sequential ionization via single-electron processes and the observed signal can only be explained by taking into account the full multiplet structure of the involved configurations and by inclusion of two-electron processes. The competing process of two-photon ionization from the ground state of Ar6+ is calculated to be orders of magnitude smaller

    Comparing evaluation of trimming machinery in the silver carp fillet

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    Trimming means is cutting fillet for a better shape, packing and marketing. The objective of this study was comparing trimming by hand and machinery from Silver Carp fillet. The aims of this project introduce best type of fillet trimming and machine for Silver Carp fillet. For first time we measured percentage different organs like head , skin, tails, intestine organs , type of bone and fillet in whole fish before and after cutting , filleting and trimming . The results show percentage of waste in trimming by machinery line processing was less than handing, and fillet trimming speed by hand was most than machinery. Also final results of this study show machinery method or complex of handing and machinery for Silver Carp fillet trimming are best

    Strain in InP/ZnSe, S core/shell quantum dots from lattice mismatch and shell thickness : material stiffness influence

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    We investigate the buildup of strain in InP quantum dots with the addition of shells of the lower-lattice constant materials ZnSe and ZnS by Raman spectroscopy. Both materials induce compressive strain in the core, which increases with increasing shell volume. We observe a difference in the shell behavior between the two materials: the thickness-dependence points toward an influence of the material stiffness. ZnS has a larger Young's modulus and requires less material to develop stress on the InP lattice at the interface, while ZnSe requires several layers to form a stress-inducing lattice at the interface. This hints at the material stiffness being an additional parameter of relevance for designing strained core/shell quantum dots

    Evaluation the tilapia meat freshness during storage in ice and refrigerator by Quality Index Method (QIM)

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    In this study, measurement of freshness fish tilapia species) Nile Tilapia (Oreochromis niloticus) by Quality Index method in whole fish in the 4 treatments and fillets in 6 treatments intended purpose of this research is to measure the qualitative factors (sensory , chemical and microbiological evaluation) and the ratio of 3 to 1 (Ice- fish) ice cover was (mean temperature in fish during the study period between 0.1±0.05 to 0.2±0.1 °C) were kept at cool temperatures for 10 days for the measure fillet Recently, 100 fish (50 pieces, 50 pieces of black and red) and washed her head and tail, the skin and the fillet 30 for each treatment in each treatment 3 Normal packing, vacuum and modified atmosphere (Tilapia fillets treated for red and black tilapia fillets 3 treatment) with an average weight of 114.5±22.50 grams packed and refrigerated at 3°C was maintained. The results showed maximum retention time for fish stomachs empty and whole fish respectively was 9 and 7 days. Also for tilapia fillet freshness in 3 different packaging and stored at -3°C, showed fillet packaged in MAP, has the most lasting, and results by the analysis Statistical was significant

    Compound words are decomposed regardless of semantic transparency and grammatical class : an fMRI study in Persian

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    202203 bckwNot applicableOthersIran Cognitive Sciences and Technologies CouncilPublished24 month

    Circular Dichroism in Multiphoton Ionization of Resonantly Excited He+He^{+} Ions

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    Intense, circularly polarized extreme-ultraviolet and near-infrared (NIR) laser pulses are combined to double ionize atomic helium via the oriented intermediate He+(3p) resonance state. Applying angle-resolved electron spectroscopy, we find a large photon helicity dependence of the spectrum and the angular distribution of the electrons ejected from the resonance by NIR multiphoton absorption. The measured circular dichroism is unexpectedly found to vary strongly as a function of the NIR intensity. The experimental data are well described by theoretical modeling and possible mechanisms are discussed
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