Multiplicity and pseudorapidity distributions of charged particles from32S induced heavy ion interactions at 200A GeV

Multiplicity and pseudorapidity distributions have been measured for³²S+Al, Cu, Ag and Au at 200A GeV. The widths of the pseudorapidity distributions increase from central to peripheral collisions. The main contribution is assumed to come from the increasing fraction of charged particles stemming from the fragmentation of the target for peripheral collisions as compared to central collisions. On the average 170–180 charged particles per unit of pseudorapidity are attained for the most central³²S+Au events at the maximum of the distribution. The target dependence of the yield of charged particles for central collisions is investigated. In the target rapidity region the yield is directly proportional to the target mass. The transverse energy per charged particle has been studied as a function of centrality and pseudorapidity. The experimental results are compared to the results from the Monte-Carlo model VENUS 3.11 which includes rescattering among secondaries. A comparison between different centrality triggers is made.     

Thermoluminescence of rare earth activated CdSO4, SrSO4 and BaSO4

The thermoluminescence (TL) of rare earth (RE) activated sulfates of Cd, Sr and Ba was studied above room temperature. Many of the phosphors prepared exhibit an extremely bright TL following X-irradiation (most notably with Sm, Eu, Tb, Dy and Tm dopants), having an efficiency comparable to that of the highest sensitivity phosphors available for TL dosimetry, and exhibiting activator-induced glow peaks between 405 and 480°K. In a given lattice, the RE³⁺ ions produce a characteristic glow peak at the same temperature (independent of the particular RE ion), whereas Eu²⁺ produces a single glow peak at a different temperature. A decrease in glow peak temperature with increasing interatomic spacing was observed in the homologous SrSO₄-BaSO₄ system - this shift being most pronounced in the Eu²⁺ -doped materials. TL emission spectra were obtained for trivalent Sm, Tb, Dy and Tm and for divalent Eu in these sulfates (and also in CaSO₄).     

Positive semidefinite zero forcing

The positive semidefinite zero forcing number _Z+(G)${\mathrm{Z}}_{+}(G)$ of a graph G was introduced in Barioli et al. (2010) [4]. We establish a variety of properties of _Z+(G)${\mathrm{Z}}_{+}(G)$: Any vertex of G   can be in a minimum positive semidefinite zero forcing set (this is not true for standard zero forcing). The graph parameters tw(G)$\mathrm{tw}(G)$ (tree-width), _Z+(G)${\mathrm{Z}}_{+}(G)$, and Z(G)$\mathrm{Z}(G)$ (standard zero forcing number) all satisfy the Graph Complement Conjecture (see Barioli et al. (2012) [3]). Graphs having extreme values of the positive semidefinite zero forcing number are characterized. The effect of various graph operations on positive semidefinite zero forcing number and connections with other graph parameters are studied.     

Synthesis and characterization of arc deposited magnetic (Cr,Mn)2AlC MAX phase films

(Cr_1–xMn_x)₂AlC MAX phase thin films were synthesized by cathodic arc deposition. Scanning transmission electron microscopy including local energy dispersive X‐ray spectroscopy analysis of the as‐deposited films reveals a Mn incorporation of as much as 10 at% in the structure, corresponding to x = 0.2. Magnetic properties were characterized with vibrating sample magnetometry, revealing a magnetic response up to at least room temperature. We thus verify previous theoretical predictions of an antiferromagnetic or ferromagnetic ground state for Cr₂AlC upon alloying with Mn. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Chiral de Rham Complex on Riemannian Manifolds and Special Holonomy

Interpreting the chiral de Rham complex (CDR) as a formal Hamiltonian quantization of the supersymmetric non-linear sigma model, we suggest a setup for the study of CDR on manifolds with special holonomy. We show how to systematically construct global sections of CDR from differential forms, and investigate the algebra of the sections corresponding to the covariantly constant forms associated with the special holonomy. As a concrete example, we construct two commuting copies of the Odake algebra (an extension of the N = 2 superconformal algebra) on the space of global sections of CDR of a Calabi-Yau threefold and conjecture similar results for G ₂ manifolds. We also discuss quasi-classical limits of these algebras.     

The role of electron-hole pair excitations in the optical absorption of metals,particularly metal spheres

It is shown that electron-hole pair excitations can dominate the optical absorption of a small metal sphere over the entire frequency range up to the bulk plasma frequency. The limited size has the effect of giving more surface to volume, thereby giving a larger relative weight to the single particle excitations, predominantly produced in the surface region, as compared to the planar case where they make up for a smaller part of the total absorptance.     

The use of alpha particle back-scattering for the study of printed and coated layers

A 1.8 MeV He-beam from a Van de Graaff accelerator has been used to demonstrate that back-scattering techniques can be usefully applied to study certain problems related to the interaction between coatings and paper substrates and between printing inks and coated or uncoated paper or plastic substrates. In particular, information on distribution profiles of various components can be obtained. The technique and some of its practical aspects are briefly described.     

Influence of different deactivation methods on the sorption properties of diatomaceous supports for GLC

Summary Different types of diatomaceous supports, (pink and white) were deactivated in different ways: HCl gas treatment at high temperature, silanization and polymer coating with Carbowax 20 M. The adsorption effects of those supports when not coated with stationary phase were tested with samples of different polarity. The Carbowax modification of supports gives a surface of very low activity, irrespective of whether the pink or the cleaner white diatomite type was the initial material. The polymer coating behaves like a thin-layer of stationary phase, of considerably less polarity than the original Carbowax, and gives rise to a partition-like retention. The silanized supports are of moderate activity, the white type being less active than the pink one. This is explained by the higher content of aprotonic active sites in the latter, which cannot be blocked by silanization.     

Utility and Considerations of Donor–Donor Energy Migration as a Fluorescence Method for Exploring Protein Structure-Function

This review aims at surveying the use of electronic energy transport between chemically identical fluorophores (i.e. donors) in studies of various protein systems. Applications of intra- and interprotein energy migration are presented that make use of polarised steady-state and time-resolved fluorescence spectroscopic techniques. The donor-donor energy migration (DDEM) and the partial donor-donor energy migration (PDDEM) models for calculating distances between donor groups are exposed together with the most recent development of an extended Forster theory (EFT). Synthetic fluorescence depolarisation data that mimic time-correlated single photon counting experiments were generated using the EFT, and then further re-analysed by the different models. The results obtained were compared with the known parameters used to generate EFT data. Aspects on how to adopt the EFT in the analyses of time-correlated single photon counting experiments are also presented, as well as future aspects on using energy migration for examining protein structure.