258 research outputs found

    Synthetic guidelines for the precision engineering of gold nanoparticles

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    Gold nanoparticles (AuNPs) are one of the most studied nanomaterials with applications spanning from catalysis to biomedicine. While numerous chemical protocols exist that allow bespoke tailoring of chemical, physical and biological properties, their translation towards industrial-scale production remains a challenge. Batch synthesis often suffers from poor reproducibility and scalability, while emerging approaches, such as continuous flow synthesis, are not widely implemented in research labs. Herein, we provide a critical review of recent developments in the field of AuNP synthesis and identify synthetic guidelines for precision engineering of nanoparticle properties

    Optical characterization of nanocomposite polymer formed by ion implantation of boron

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    © 2017, Springer Science+Business Media New York.The boron-ion-implanted polymethylmethacrylate (B:PMMA) samples formed with an energy of 40 keV, ion doses ranging from 6.25 × 1014 to 2.5 × 1016 B+/cm2, and current density of 1016 B+/cm2) in the course of ion-induced carbonization are observed. The value of optical band gap energy of boron-ion-implanted layer Egopt,B was estimated given thickness of implanted layer as a maximum penetration depth of B+ ions into PMMA by slow positron beam spectroscopy in agreement with SRIM simulation results. On the basis of Egopt,B values, a number of carbon atoms in carbonaceous clusters N for the B:PMMA was calculated. It is found the existence of three regions of ion doses (1) 6.25 × 1014 ÷ 3.13 × 1015 B+/cm2, (2) 3.75 × 1015 ÷ 6.25 × 1015 B+/cm2, and (3) 1.25 × 1016 ÷ 2.5 × 1016 B+/cm2, showing thresholds in the estimated Egopt,B and N values as a function of ion dose for the B:PMMA studied. The ion-induced structural evolution towards formation of carbon nanostructures within these thresholds is suggested as explanation of experimental results, taking into account the possible carbonization in high-dose B:PMMA nanocomposite films

    Physiological Response of Three Grapevine Cultivars Grown In North-Western Poland to Mycorrhizal Fungi

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    West Pomerania (Poland) is located near the northern boundary of the range of viticulture (the coldest zone A). Unfavourable weather conditions can pose a serious threat to the cultivated vines. One of the treatments used to increase the tolerance of plants to abiotic and biotic stresses is inoculation with symbiotic soil microorganisms. This paper focuses on the influence of mycorrhization on the changes in soil microbiology, the degree of colonization of roots by mycorrhizal fungi, and on selected physiologicalparameters of three grapevine cultivars (‘Pinot Noir’ on SO4 rootstock, ‘Regent’ on 5BB rootstock, and ‘Rondo’ on 125AA rootstock). The applied inoculation had a stimulating effect on the colonization of roots by arbuscular mycorrhizal (AM) fungi, as evidenced by higher mycorrhizal frequency and intensity in the mycorrhized plants. The mycorrhizal treatment increased the intensity of CO2 assimilation and transpiration. Mycorrhization reduced the efficiency of photosynthetic water use and increased stomatal conductance for water in the grapevines tested. The mycorrhizal treatment did not affect the concentration of assimilation pigments in vine leaves. The mycorrhization of grapevines had no effect on the values of initial fluorescence, maximum fluorescence, the maximum potential efficiency of photochemical reaction in PS II, the size of the pool of reduced electron acceptors in PS II, nor on the value of the PS II vitality index

    Fragmentation in Peripheral Heavy-Ion Collisions: from Neck Emission to Spectator Decays

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    Invariant cross sections of intermediate mass fragments in peripheral collisions of Au on Au at incident energies between 40 and 150 AMeV have been measured with the 4-pi multi-detector INDRA. The maximum of the fragment production is located near mid-rapidity at the lower energies and moves gradually towards the projectile and target rapidities as the energy is increased. Schematic calculations within an extended Goldhaber model suggest that the observed cross-section distributions and their evolution with energy are predominantly the result of the clustering requirement for the emerging fragments and of their Coulomb repulsion from the projectile and target residues. The quantitative comparison with transverse energy spectra and fragment charge distributions emphasizes the role of hard scattered nucleons in the fragmentation process.Comment: 5 pages, 5 eps figures, RevTeX4, submitted to Phys. Lett.

    Thermal and Chemical Freeze-out in Spectator Fragmentation

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    Isotope temperatures from double ratios of hydrogen, helium, lithium, beryllium, and carbon isotopic yields, and excited-state temperatures from yield ratios of particle-unstable resonances in 4He, 5Li, and 8Be, were determined for spectator fragmentation, following collisions of 197Au with targets ranging from C to Au at incident energies of 600 and 1000 MeV per nucleon. A deviation of the isotopic from the excited-state temperatures is observed which coincides with the transition from residue formation to multi-fragment production, suggesting a chemical freeze-out prior to thermal freeze-out in bulk disintegrations.Comment: 14 pages, 10 figures, submitted to Phys. Rev. C, small changes as suggested by the editors and referee

    Statistical Multifragmentation of Non-Spherical Expanding Sources in Central Heavy-Ion Collisions

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    We study the anisotropy effects measured with INDRA at GSI in central collisions of Xe+Sn at 50 A.MeV and Au+Au at 60, 80, 100 A.MeV incident energy. The microcanonical multifragmentation model with non-spherical sources is used to simulate an incomplete shape relaxation of the multifragmenting system. This model is employed to interpret observed anisotropic distributions in the fragment size and mean kinetic energy. The data can be well reproduced if an expanding prolate source aligned along the beam direction is assumed. An either non-Hubblean or non-isotropic radial expansion is required to describe the fragment kinetic energies and their anisotropy. The qualitative similarity of the results for the studied reactions suggests that the concept of a longitudinally elongated freeze-out configuration is generally applicable for central collisions of heavy systems. The deformation decreases slightly with increasing beam energy.Comment: 35 pages, 19 figures, submitted to Nuclear Physics

    Viininmaistelun alkeet -tapahtuma Maria P:ssä

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    Tiivistelmä Tekijät: Paananen Riina ja Korkiakoski Merika Työn nimi: Viininmaistelun alkeet -tapahtuma Maria P:ssä Tutkintonimike: Restonomi (AMK), matkailun koulutus Asiasanat: tapahtuma, viini, viininmaistelu, Chile Opinnäytetyön tarkoituksena oli suunnitella ja järjestää Viininmaistelun alkeet -tapahtuma. Tapahtuman toimeksiantajana toimi kajaanilainen yritys Viinibaari Maria P. Tapahtuma haluttiin toteuttaa baarin imagoon sopivaksi. Opinnäytetyön tavoitteena oli saada Viini-baarille lisää asiakkaita tutustuttamalla kokemattomia viininmaistajia viineihin. Työ oli toiminnallinen opinnäytetyö, jonka tuotoksena oli Viininmaistelun alkeet -tapahtuma. Opinnäytetyöhön kerättiin teoriapohjaa viininmaistelusta sekä viinin ja ruoan yhdistämisestä, Chilestä viinimaana ja tapahtuman järjestämisestä. Näitä kaikkia käytettiin lopullisen tuotoksen valmistumiseen. Toteutuksen arviointina toimi tapahtumaan osallistuneilta saatu kirjallinen palaute. Palautteen mukaan kehittämistehtävän toteutuksessa onnistuttiin hyvin, sillä opinnäytetyön ennalta määritellyt tavoitteet saavutettiin. Opinnäytetyötä voidaan käyttää apuna jatkossa vastaavien tapahtumien suunnittelussa.Abstract Authors: Paananen Riina & Korkiakoski Merika Title of the Publication: Basics of wine tasting- event Degree title: Bachelor of Hospitality Management Keywords: event, wine, tasting, Chile The purpose for this thesis was to plan and arrange Basics of wine tasting –event. The commissioner for this thsesis was a local bar in Kajaani called Viinibaari Maria P. The event was planned to suit the imago of the bar. The objective of the thesis was to gain more customers to Viinibaari Maria P by introducing various wines to novice wine tasters. This research was a functional thesis which produced the Basics wine tasting event. The theory of this thesis focused on wine tasting, combining wine and food, Chile as a wine producer, and on planning and arranging an event. The feedback for the execution consists of the feedback forms that the customers of the event were asked to fill in. In addition observation method was used for evaluation. According to the feedback the event was successful because the objective of the thesis was reached. Our conclusion is that this thesis can be used as a guide in planning similar events

    ABC Effect and Resonance Structure in the Double-Pionic Fusion to 3^3He

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    Exclusive and kinematically complete measurements of the double pionic fusion to 3^3He have been performed in the energy region of the so-called ABC effect, which denotes a pronounced low-mass enhancement in the ππ\pi\pi-invariant mass spectrum. The experiments were carried out with the WASA detector setup at COSY. Similar to the observations in the basic pndπ0π0pn \to d \pi^0\pi^0 reaction and in the dd4dd \to ^4Heπ0π0\pi^0\pi^0 reaction, the data reveal a correlation between the ABC effect and a resonance-like energy dependence in the total cross section. Differential cross sections are well described by the hypothesis of dd^* resonance formation during the reaction process in addition to the conventional tt-channel ΔΔ\Delta\Delta mechanism. The deduced dd^* resonance width can be understood from collision broadening due to Fermi motion of the nucleons in initial and final nuclei

    Charge Symmetry Breaking in dd->4He{\pi}0 with WASA-at-COSY

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    Charge symmetry breaking (CSB) observables are a suitable experimental tool to examine effects induced by quark masses on the nuclear level. Previous high precision data from TRIUMF and IUCF are currently used to develop a consistent description of CSB within the framework of chiral perturbation theory. In this work the experimental studies on the reaction dd->4He{\pi}0 have been extended towards higher excess energies in order to provide information on the contribution of p-waves in the final state. For this, an exclusive measurement has been carried out at a beam momentum of p=1.2 GeV/c using the WASA-at-COSY facility. The total cross section amounts to sigma(tot) = (118 +- 18(stat) +- 13(sys) +- 8(ext)) pb and first data on the differential cross section are consistent with s-wave pion production.Comment: 14 pages, 5 figure

    Neutron-Proton Scattering in the Context of the dd^*(2380) Resonance

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    New data on quasifree polarized neutron-proton scattering, in the region of the recently observed dd^* resonance structure, have been obtained by exclusive and kinematically complete high-statistics measurements with WASA at COSY. This paper details the determination of the beam polarization, checks of the quasifree character of the scattering process, on all obtained AyA_y angular distributions and on the new partial-wave analysis, which includes the new data producing a resonance pole in the 3D3^3D_3-3G3^3G_3 coupled partial waves at (2380±10i40±52380\pm10 - i40\pm5) MeV -- in accordance with the dd^* dibaryon resonance hypothesis. The effect of the new partial-wave solution on the description of total and differential cross section data as well as specific combinations of spin-correlation and spin-transfer observables available from COSY-ANKE measurements at TdT_d = 2.27 GeV is discussed
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