A partial-wave analysis of the 3π system in the reaction K−p → π+π−π0Λ at 4.2 GeV/c

A partial-wave analysis of the (3π)⁰ system produced peripherally in the reaction K^?p → π⁺π^?π⁰Λ at 4.2 GeV/c is presented. The observation of the weak Λ decay allows a determination of all the transversity production amplitudes except for two phases. The production of known resonances having decay modes other than 3π is used to test the isobar model ansatz. Significant ω(783), φ(1020) and A₂(1310) production is observed. The spin parity of the $\text{ω}{}^1\text{(1675)}$ is established as 3^?. No evidence for production of other resonances, such as axial vector-mesons, is found.     

Amplitude analysis for the process K− p → (π+ π−)s-wave ϵ0 (1385)

Transversity amplitudes and spin density matrix elements are determined for the process K^? p → (π⁺ π^?)_s-wave ?⁰(1385). Predictions of the additive quark model and of duality diagrams are tested and found consistent with the data; this is the first information about the applicability of these models to processes where a scalar object is produced at the mesonic vertex.     

Rare decay modes of K1(1420) and K1(892)

A 2.5 standard deviation signal is observed for the decay $\text{K}{}^{\mathrm{1?}}\text{(1420) →}\text{K}{}^{\mathrm{1?}}\text{(892)π}{}^{\mathrm{+}}\text{π}{}^{\mathrm{?}}$. From this signal a partial width of 13.0 ± 5.0 MeV for the decay mode $\text{K}{}^1\text{(1420)→}\text{K}{}^1\text{(892)ππ}$ is deduced under the assumption that the ππ system is in an I = 1 state. For the rare decay mode $\text{K}{}^1\text{(892)→}\text{K}\text{ππ}$ no signal is observed. The following upper limits can be given for the decay widths: , , .     

Modeling and innovative technology of optical 3D antenna sensors as micro rectangular apertures

Optical and Quantum Electronics - In this paper we present a novel model for the design of micrometric optical antennas applied to the detection of skin melanomas. The accuracy of the model allows...     

In situ formation and size control of gold nanoparticles into chitosan for nanocomposite surfaces with tailored wettability

The in situ formation of gold nanoparticles into the natural polymer chitosan is described upon pulsed laser irradiation. In particular, hydrogel-type films of chitosan get loaded with the gold precursor, chloroauric acid salt (HAuCl(4)), by immersion in its aqueous solution. After the irradiation of this system with increasing number of ultraviolet laser pulses, we observe the formation of gold nanoparticles with increasing density and decreasing size. Analytical studies using absorption measurements, atomic force microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy of the nanocomposite samples throughout the irradiation procedure reveal that under the specific irradiation conditions there are two competing mechanisms responsible for the nanoparticles production: the photoreduction of the precursor responsible for the rising growth of gold particles with increasing size and the subsequent photofragmentation of these particles into smaller ones. The described method allows the localized formation of gold nanoparticles into specific areas of the polymeric films, expanding its potential applications due to its patterning capability. The size and density control of the gold nanoparticles, obtained by the accurate increase of the laser irradiation time, is accompanied by the simultaneously controlled increase of the wettability of the obtained gold nanocomposite surfaces. The capability of tailoring the hydrophilicity of nanocomposite materials based on natural polymer and biocompatible gold nanoparticles provides new potentialities in microfluidics or lab on chip devices for blood analysis or drugs transport, as well as in scaffold development for preferential cells growth.     

Catalytic enantioselective synthesis of fluoromethylated stereocenters by asymmetric hydrogenation

Fluoromethyl groups possess specific steric and electronic properties and serve as a bioisostere of alcohol, thiol, nitro, and other functional groups, which are important in an assortment of molecular recognition processes. Herein we report a catalytic method for the asymmetric synthesis of a variety of enantioenriched products bearing fluoromethylated stereocenters with excellent yields and enantioselectivities. Various N,P-ligands were designed and applied in the hydrogenation of fluoromethylated olefins and vinyl fluorides.

Herein, a catalytic asymmetric hydrogenation to synthesize various products bearing fluoromethylated stereocenters has been developed.     

N-picolinamides as ligands for Ullmann-type homocoupling reactions

The use of N-phenylpicolinamide (NPPA) as a ligand in Ullmann-type homocoupling reactions of aryl iodides and bromides in common solvents, such as DMF and MeCN has been successfully demonstrated at room temperature. In addition, this work provided the first example of the homocoupling of an aryl chloride at 82 °C, which is a relatively low temperature when compared to regular Ullmann reaction temperatures. Also, NPPA was successfully employed in base—and heat free Suzuki reactions, including electron rich and poor aryl halides with heteroarylboronic acids in moderate yields.     

First‐principle modelling of forsterite surface properties: Accuracy of methods and basis sets

The seven main crystal surfaces of forsterite (Mg₂SiO₄) were modeled using various Gaussian‐type basis sets, and several formulations for the exchange‐correlation functional within the density functional theory (DFT). The recently developed pob‐TZVP basis set provides the best results for all properties that are strongly dependent on the accuracy of the wavefunction. Convergence on the structure and on the basis set superposition error‐corrected surface energy can be reached also with poorer basis sets. The effect of adopting different DFT functionals was assessed. All functionals give the same stability order for the various surfaces. Surfaces do not exhibit any major structural differences when optimized with different functionals, except for higher energy orientations where major rearrangements occur around the Mg sites at the surface or subsurface. When dispersions are not accounted for, all functionals provide similar surface energies. The inclusion of empirical dispersions raises the energy of all surfaces by a nearly systematic value proportional to the scaling factor s of the dispersion formulation. An estimation for the surface energy is provided through adopting C₆ coefficients that are more suitable than the standard ones to describe O? O interactions in minerals. A 2 × 2 supercell of the most stable surface (010) was optimized. No surface reconstruction was observed. The resulting structure and surface energy show no difference with respect to those obtained when using the primitive cell. This result validates the (010) surface model here adopted, that will serve as a reference for future studies on adsorption and reactivity of water and carbon dioxide at this interface. © 2015 Wiley Periodicals, Inc.     

Backward production of a spin-parity 1+ Kϱ resonance at 1.28 GeV

A (K_ππ)⁺ mass enhancement is observed in the reactions K^?p → Ξ ?K^o+π⁺π^o? when events with a small (K^? → Ξ^?) four momentum transfer squared are selected. The signal is also visible in the reaction K^?p → Ξ^?π⁺+ neutrals. The enhancement, centered at 1.28 GeV, is seen to decay preferentially into K? with spin-parity J^P = 1⁺. The cross section for K^?p→ Ξ^?C⁺(1.28) with C⁺ → K? at 4.15 GeV/c incident K^? momentum is (6.2 ± 0.6) μb.