919 research outputs found

    Optimal performance of equilibrium parametric pumps

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    An examination of the conditions required to obtain the optimal performance of semicontinuous and continuous parametric pumps, defined by the achieving of the maximum possible solute free product for a given column height, was undertaken. The model system sodium nitrate ? water on an ion retardation resin adsorbate was employed. Equations defining maximum values of certain important parameters such as the bottom product flow rate and reservoir displacement rate were developed by extending previous theories of parametric pumping. Experimental runs were carried out using parameters whose values were both less than and greater than the maximum values predicted for optimal performance. It was found that for pumps operating with parameter values less than the limiting maximum values, complete removal of solute from the bottom of the column was obtained. Furthermore, for those pumps for which the parameter values were greater than the predicted maximum quantities only partial removal of solute was observed. The experimental results agreed quantitatively as well as qualitatively with the theory for almost all runs

    The complementary role of imaging and tumor biomarkers in gynecological cancers: an update of the literature

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    Gynecological tumors, including endometrial, cervical and ovarian cancer, have increased in incidence over time. The widespread introduction of screening programs and advances in diagnostic imaging methods has lead to a progressive increase in gynecological cancer detection. Accurate diagnosis and proper monitoring of disease remain the primary target for a successful treatment. In the last years, knowledge about cancer biomarkers has considerably increased providing great opportunities for improving cancer detection and treatment. In addition, in the last few years there has been an important development of imaging techniques. Nowadays, a multimodal approach including the evaluation of serum tumor biomarkers combined with imaging techniques, seems to be the best strategy for assessing tumor presence, spread, recurrence, and/or the response to treatment in female cancer patients In this review we provide an overview of the application of biomarkers combined with novel imaging methods and highlight their roles in female cancer diagnosis and follow-up

    Mechanisms producing fissionlike binary fragments in heavy collisions

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    The mixing of the quasifission component to the fissionlike cross section causes ambiguity in the quantitative estimation of the complete fusion cross section from the observed angular and mass distributions of the binary products. We show that the partial cross section of quasifission component of binary fragments covers the whole range of the angular momentum values leading to capture. The calculated angular momentum distributions for the compound nucleus and dinuclear system going to quasifission may overlap: competition between complete fusion and quasifission takes place at all values of initial orbital angular momentum. Quasifission components formed at large angular momentum of the dinuclear system can show isotropic angular distribution and their mass distribution can be in mass symmetric region similar to the characteristics of fusion-fission components. As result the unintentional inclusion of the quasifission contribution into the fusion-fission fragment yields can lead to overestimation of the probability of the compound nucleus formation.Comment: 15 pages, 6 figures, International Conference on Nuclear Reactions on Nucleons and Nuclei, Messina, Italy, October 5-9, 200

    Suppression of threading defects formation during Sb-assisted metamorphic buffer growth in InAs/InGaAs/InP structure

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    A virtual substrate for high quality InAs epitaxial layer has been attained via metalorganic vapor-phase epitaxy growth of Sb-assisted InxGa1-xAs metamorphic buffers, following a convex compositional continuous gradient of the In content from x = 53 % to 100 %. The use of trimethylantimony (or its decomposition products) as a surfactant has been found to crucially enable the control over the defect formation during the relaxation process. Moreover, an investigation of the wafer offcut-dependence of the defect formation and surface morphology has enabled the achievement of a reliably uniform growth on crystals with offcut towards the [111]B direction

    Quasifission and fusion-fission in massive nuclei reactions. Comparison of reactions leading to the Z=120 element

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    The yields of evaporation residues, fusion-fission and quasifission fragments in the 48^{48}Ca+144,154^{144,154}Sm and 16^{16}O+186^{186}W reactions are analyzed in the framework of the combined theoretical method based on the dinuclear system concept and advanced statistical model. The measured yields of evaporation residues for the 48^{48}Ca+154^{154}Sm reaction can be well reproduced. The measured yields of fission fragments are decomposed into contributions coming from fusion-fission, quasifission, and fast-fission. The decrease in the measured yield of quasifission fragments in 48^{48}Ca+154^{154}Sm at the large collision energies and the lack of quasifission fragments in the 48^{48}Ca+144^{144}Sm reaction are explained by the overlap in mass-angle distributions of the quasifission and fusion-fission fragments. The investigation of the optimal conditions for the synthesis of the new element ZZ=120 (AA=302) show that the 54^{54}Cr+248^{248}Cm reaction is preferable in comparison with the 58^{58}Fe+244^{244}Pu and 64^{64}Ni+238^{238}U reactions because the excitation function of the evaporation residues of the former reaction is some orders of magnitude larger than that for the last two reactions.Comment: 27 pages, 12 figures, submitted to Phys. Rev.

    Unusual nanostructures of "lattice matched" InP on AlInAs

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    We show that the morphology of the initial monolayers of InP on Al0.48In0.52As grown by metalorganic vapor-phase epitaxy does not follow the expected layer-by-layer growth mode of lattice-matched systems, but instead develops a number of low-dimensional structures, e.g., quantum dots and wires. We discuss how the macroscopically strain-free heteroepitaxy might be strongly affected by local phase separation/alloying-induced strain and that the preferred aggregation of adatom species on the substrate surface and reduced wettability of InP on AlInAs surfaces might be the cause of the unusual (step) organization and morpholog
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