Particle-hole nature of the two lowest 3−states in 24Mg

Stripping and pickup reactions are performed and show the configuration for the lowest 3^?state (7.62MeV) to be mainly a hole in the 1p shell the next 3^?level (8.36 MeV) is mainly promoted into the 2p-1f shell.     

An amplitude analysis of ππ scattering from new data on the reaction π−p→π+π−n

We have carried out a partial-wave analysis of ππ scattering in the mass range 1.0 to 2.08 GeV/c². We find solutions similar to those obtained in previous analyses below 1.8 GeV/c² but, in addition, we obtain a new solution which does not suffer from violations of unitarity and is compatible with data from other channels. This solution, when continued to 2.08 GeV/c², shows a g meson with mass and width of 1.734± 0.010 GeV/c²and 0.322±0.035 GeV/c² respectively, and an h meson with mass 1.935±0.013 GeV/c²and width 0.263±0.057 GeV/c². The L = 2 partial wave contains the f meson and an additional resonance with parameters m = 1.502±0.025 Gev/c², Γ = 0.165±0.042 GeV/c²and x = 0.19±0.03. If we associate this state with the f′(1514), our ππ branching fraction is considerably higher than previous determinations. An SU(3) fit to the 2⁺ nonet yields a mixing angle of 38.4± 1.3°.     

Generation of GW radiation pulses from a VUV free-electron laser operating in the femtosecond regime

Experimental results are presented from vacuum-ultraviolet free-electron laser (FEL) operating in the self-amplified spontaneous emission (SASE) mode. The generation of ultrashort radiation pulses became possible due to specific tailoring of the bunch charge distribution. A complete characterization of the linear and nonlinear modes of the SASE FEL operation was performed. At saturation the FEL produces ultrashort pulses (30-100 fs FWHM) with a peak radiation power in the GW level and with full transverse coherence. The wavelength was tuned in the range of 95-105 nm.     

Production of muon pairs in the continuum region by 39.5 GeV/cπ±, K±, p and p beams incident on a copper target

General features of the inclusive hadroproduction of muon pairs of mass greater than 1.5 GeV/c² are shown. For incident π^?, the data extend up to M=5.7 GeV/c² (i.e.M²/s≈0.4). The scaling cross section M³dσ/dM for π^?N reactions is much flatter than that for pN reactions and exceeds the latter by two to three orders of magnitude at large M²/s.     

Bio-deuterated cellulose thin films for enhanced contrast in neutron reflectometry

Novel molecularly smooth, flat and thin films of regenerated bio-deuterated cellulose were produced for enhanced contrast with adsorbed molecules in neutron reflectivity (NR) and for cellulose structure studies. The cellulose films were produced to study both the solid/air interface and the solid/liquid interface. Cellulose films with a wide range of scattering contrast were achieved by combining exchange of ¹H for deuterium on hydroxyl groups via water in the liquid phase and via biosynthesis of deuterated bacterial cellulose by Gluconacetobacter xylinus which can deuterate the hydrogens bonded to carbon atoms in cellulose. The deuterated cellulose combined with NR will help to provide new information on the interaction of various (bio)-macromolecules and cellulose. This includes quantifying and visualizing the density profile of polymers and biomolecules adsorbed onto cellulose surface. The potential of this material for IR studies of materials adsorbed to cellulose films is briefly discussed.     

High aspect ratio nanocellulose from an extremophile spinifex grass by controlled acid hydrolysis

During the last two decades, work surrounding the preparation of a vast array of cellulose nanomaterials from both wood and non-wood based sources has steadily intensified. This study reports on the isolation of high aspect ratio nanocellulose from an arid grass source commonly called “spinifex”, Triodia pungens, via an optimised sulfuric acid hydrolysis protocol. The unique attributes of T. pungens have enabled pulping and bleaching under milder conditions than used in typically reported protocols, followed by relatively easy deconstruction into nanofibres with an unprecedentedly high aspect ratio. Hydrolysis of bleached T. pungens under these optimised processing conditions has yielded nanocellulose with a very high aspect ratio of 144 (average dimensions of 3.45 ± 1 nm × 497 ± 106 nm), a crystallinity of 73% and a production yield of 42%. Based on the spectroscopic and X-ray scattering analyses, an unusually high content of hemicellulose (42%) is correlated with both the ease of deconstruction and the retention of nanocellulose length. This high hemicellulose content also appears to give rise to a lower transverse stiffness than previously-reported values for wood sources.     

Meso-structure formation for enhanced organic photovoltaic cells

[reaction: see text] Formation of a controlled fullerene mesophase within an organic host system has enabled us to create high-power conversion efficiency photovoltaics. This mesophase is formed using thermal gradients that provide a fluidic mobility of the fullerenes allowing for greater dispersion of nanocrystalline 1-(3-methoxycarbonyl)propyl-1-phenyl-(6,6)C61 (PCBM) within regioregular poly(3-hexylthiophene) (P3HT). From this reorganization of the component materials in the matrix the overall efficiency of the system jumps dramatically from the roughly 2.4% to 5.2%.     

Use of the E-vinyloxyborane derived from S-phenyl propanethioate for stereospecific aldol-type condensation. A simplified synthesis of the prelog-djerassi lactonic acid

The $\text{E}$-vinyloxyborane ($\text{5}$), prepared from S-phenyl propanethioate, 9-BBN triflate, and diisopropylethylamine, reacts stereoselectively with aldehydes to provide $\text{erythro}$-β-hydroxy-α-methylcarboxylic acid thiol esters. This reaction has been applied to a synthesis of Prelog-Djerassi lactonic acid ($\text{6}$).