10,329 research outputs found
Simultaneous analysis of elastic scattering and transfer/breakup channels for the 6He+208Pb reaction at energies near the Coulomb barrier
The elastic and alpha-production channels for the 6He+208Pb reaction are
investigated at energies around the Coulomb barrier (E_{lab}=14, 16, 18, 22,
and 27 MeV). The effect of the two-neutron transfer channels on the elastic
scattering has been studied within the Coupled-Reaction-Channels (CRC) method.
We find that the explicit inclusion of these channels allows a simultaneous
description of the elastic data and the inclusive alpha cross sections at
backward angles. Three-body Continuum-Discretized Coupled-Channels (CDCC)
calculations are found to reproduce the elastic data, but not the
transfer/breakup data. The trivially-equivalent local polarization potential
(TELP) derived from the CRC and CDCC calculations are found to explain the
features found in previous phenomenological optical model calculations for this
system.Comment: 7 pages, 6 figures (replaced with updated version
Large area Al₂O₃–Au raspberry-like nanoclusters from iterative block-copolymer self-assembly
In the field of functional nanomaterials, core–satellite nanoclusters have recently elicited great interest due to their unique optoelectronic properties. However, core–satellite synthetic routes to date are hampered by delicate and multistep reaction conditions and no practical method has been reported for the ordering of these structures onto a surface monolayer. Herein we show a reproducible and simplified thin film process to fabricate bimetallic raspberry nanoclusters using block copolymer (BCP) lithography. The fabricated inorganic raspberry nanoclusters consisted of a ∼36 nm alumina core decorated with ∼15 nm Au satellites after infusing multilayer BCP nanopatterns. A series of cylindrical BCPs with different molecular weights allowed us to dial in specific nanodot periodicities (from 30 to 80 nm). Highly ordered BCP nanopatterns were then selectively infiltrated with alumina and Au species to develop multi-level bimetallic raspberry features. Microscopy and X-ray reflectivity analysis were used at each fabrication step to gain further mechanistic insights and understand the infiltration process. Furthermore, grazing-incidence small-angle X-ray scattering studies of infiltrated films confirmed the excellent order and vertical orientation over wafer scale areas of Al2O3/Au raspberry nanoclusters. We believe our work demonstrates a robust strategy towards designing hybrid nanoclusters since BCP blocks can be infiltrated with various low cost salt-based precursors. The highly controlled nanocluster strategy disclosed here could have wide ranging uses, in particular for metasurface and optical based sensor applications
Alterations in microbial community composition with increasing fCO2: a mesocosm study in the eastern Baltic Sea
Ocean acidification resulting from the uptake of anthropogenic carbon
dioxide (CO<sub>2</sub>) by the ocean is considered a major threat to marine
ecosystems. Here we examined the effects of ocean acidification on microbial
community dynamics in the eastern Baltic Sea during the summer of 2012 when
inorganic nitrogen and phosphorus were strongly depleted. Large-volume in
situ mesocosms were employed to mimic present, future and far future
CO<sub>2</sub> scenarios. All six groups of phytoplankton enumerated by flow
cytometry ( <  20 µm cell diameter) showed distinct trends in
net growth and abundance with CO<sub>2</sub> enrichment. The picoeukaryotic
phytoplankton groups Pico-I and Pico-II displayed enhanced abundances, whilst
Pico-III, <i>Synechococcus</i> and the nanoeukaryotic phytoplankton groups
were negatively affected by elevated fugacity of CO<sub>2</sub>
(<i>f</i>CO<sub>2</sub>). Specifically, the numerically dominant eukaryote, Pico-I,
demonstrated increases in gross growth rate with increasing <i>f</i>CO<sub>2</sub>
sufficient to double its abundance. The dynamics of the prokaryote community
closely followed trends in total algal biomass despite differential effects
of <i>f</i>CO<sub>2</sub> on algal groups. Similarly, viral abundances corresponded
to prokaryotic host population dynamics. Viral lysis and grazing were both
important in controlling microbial abundances. Overall our results point to a
shift, with increasing <i>f</i>CO<sub>2</sub>, towards a more regenerative system
with production dominated by small picoeukaryotic phytoplankton.</p
Flow-Injection Analysis of Hydrogen Peroxide Using a Horseradish Peroxidase-Modified Electrode Detection System
A flow-injection analysis (FIA) system utilizing a horseradish peroxidase-modified amperometric electrode is described. The enzyme was immobilized through adsorption onto a glassy carbon electrode and the system is used to determine hydrogen peroxide at submicromolar levels
Microwave-assisted hydrolysis and extraction of tricyclic antidepressants from human hair
The objective of this research was to develop, optimize, and validate a modern, rapid method of preparation of human hair samples, using microwave irradiation, for analysis of eight tricyclic antidepressants (TCADs): nordoxepin, nortriptyline, imipramine, amitriptyline, doxepin, desipramine, clomipramine, and norclomipramine. It was based on simultaneous alkaline hair microwave-assisted hydrolysis and microwave-assisted extraction (MAH–MAE). Extracts were analyzed by high-performance liquid chromatography with diode-array detection (HPLC–DAD). A mixture of n-hexane and isoamyl alcohol (99:1, v/v) was used as extraction solvent and the process was performed at 60°C. Application of 1.0 mol L−1 NaOH and microwave irradiation for 40 min were found to be optimum for hair samples. Limits of detection ranged from 0.3 to 1.2 μg g−1 and LOQ from 0.9 to 4.0 μg g−1 for the different drugs. This enabled us to quantify them in hair samples within average therapeutic concentration ranges
Solution of the Bosonic and Algebraic Hamiltonians by using AIM
We apply the notion of asymptotic iteration method (AIM) to determine
eigenvalues of the bosonic Hamiltonians that include a wide class of quantum
optical models. We consider solutions of the Hamiltonians, which are even
polynomials of the fourth order with the respect to Boson operators. We also
demonstrate applicability of the method for obtaining eigenvalues of the simple
Lie algebraic structures. Eigenvalues of the multi-boson Hamiltonians have been
obtained by transforming in the form of the single boson Hamiltonian in the
framework of AIM
Liver, horseradish and bananas: a diet of enzymes for voltammetry
In this paper we will report on recent work that we have carried out involving enzymes such as glutamate dehydrogenase (from liver), peroxidase (from horseradish) and tyrosinase (from banana)
The Air Microwave Yield (AMY) experiment - A laboratory measurement of the microwave emission from extensive air showers
The AMY experiment aims to measure the microwave bremsstrahlung radiation
(MBR) emitted by air-showers secondary electrons accelerating in collisions
with neutral molecules of the atmosphere. The measurements are performed using
a beam of 510 MeV electrons at the Beam Test Facility (BTF) of Frascati INFN
National Laboratories. The goal of the AMY experiment is to measure in
laboratory conditions the yield and the spectrum of the GHz emission in the
frequency range between 1 and 20 GHz. The final purpose is to characterise the
process to be used in a next generation detectors of ultra-high energy cosmic
rays. A description of the experimental setup and the first results are
presented.Comment: 3 pages -- EPS-HEP'13 European Physical Society Conference on High
Energy Physics (July, 18-24, 2013) at Stockholm, Swede
Sensors based on polymer modified electrodes
This paper will review the recent results that we have obtained using novel ruthenium-containing polymers, and on the further studies on the incorporation of proteins into polymeric matrices
- …