2–3 brother trees

2–3 brother trees form a dense class of search trees havingO(logN) insertion and deletion algorithms. In this paper we provide anO(logN) insertion algorithm and show that these trees have much better density and storage utilization than 2–3 trees. Thus we demonstrate that the brother property which has so far been used only for binary trees can be usefully applied to 2–3 trees.Work supported partially by a Natural Sciences and Engineering Research Council of Canada Grant No. A-7700 and partially by the German Academic Exchange Service under Nato Research Grant No. 430/402/584/8.     

Development of a honeycomb gas proportional counter array for photon multiplicity measurements in high multiplicity environment

A novel gas-based detector using large arrays of honeycomb cells has been developed and tested for use as a pre-shower photon multiplicity detector (PMD) for STAR and ALICE experiments. The appropriate cell design was arrived at using GARFIELD simulations. Prototype chambers with cell dimensions corresponding to STAR and ALICE were fabricated and tested at CERN PS and SPS. The charged particle detection efficiency and the pre-shower characteristics have been studied using pion and electron beams.     

Site-Selective Oxidation of Monolayered Liquid-Exfoliated WS2 by Shielding the Basal Plane through Adsorption of a Facial Amphiphile

In recent years, various functionalization strategies for transition-metal dichalcogenides have been explored to tailor the properties of materials and to provide anchor points for the fabrication of hybrid structures. Herein, new insights into the role of the surfactant in functionalization reactions are described. Using the spontaneous reaction of WS₂ with chloroauric acid as a model reaction, the regioselective formation of gold nanoparticles on WS₂ is shown to be heavily dependent on the surfactant employed. A simple model is developed to explain the role of the chosen surfactant in this heterogeneous functionalization reaction. The surfactant coverage is identified as the crucial element that governs the dominant reaction pathway and therefore can severely alter the reaction outcome. This study shows the general importance of the surfactant choice and how detrimental or beneficial a certain surfactant can be to the desired functionalization.     

Quantum tunnelling of muonium reactions in solutions

Muonium spin rotation experiments have been performed in a system of benzene in liquid isopentane solutions in the temperature range between 136 K and 295 K. The observed chemical reaction rate constants show a concave curve in an Arrhenius plot. These results are interpreted in terms of to a significant quantum tunnelling effect for muonium reaction in solutions. The oscillating frequency and the width of barrier for such reactions were found to be 400 cm^?1 and 2.1 Å respectively by curve-shape analysis. The reaction barrier (6.0 kJ/mol) is found to be less than the activation energy due to viscous flow of the solvent.     

Multiscale modeling of the surfactant mediated synthesis and supramolecular assembly of cobalt nanodots

Multiscale simulations are used to bridge the surfactant templated assembly of individual approximately 1-10 nm cobalt dots, to their ordering into supramolecular arrays. Potential energy surfaces derived from ab initio calculations are input to lattice Monte Carlo simulations at atomic scales. By this process we quantitatively reproduce the experimental cobalt nanoparticle sizes. Crucially, we find that there is an effective short range attraction between pairs of nanodots. Mesoscale simulations show that these attractive interdot potentials are so short ranged that the dots can assemble only into orientally ordered hexatic phases as in the experiments.     

Mononuclear manganese(III) aquo complexes. Crystal and molecular structures of [Mn(phen)(OH2)Cl3] and [Mn(acac)2-(OH2)2]ClO4·2H2O (acacH = acetylacetone,phen = 1,10-phenanthroline)

Summary The crystal and molecular structures of [Mn(phen)-(OH₂)Cl₃] (1) and [Mn(acac)₂(OH₂)₂]ClO₄·2H₂O (2) were determined. A comparison is made of the Jahn-Teller distortion in these compounds with those observed in other manganese(III) complexes with monodentate axial ligands.     

Chemical dynamics of muonium in liquids

The bimolecular rate constants for muonium addition to ethene (CH₂=CH₂) in hydrocarbon liquids were found to be ∼2×10¹⁰ M⁻¹s⁻¹. These rate constants change with temperature in accordance with the Arrhenius equation; but the energy barrier to reaction (E_a) in 2-methylbutane is much less than that for viscous flow. This suggests either non-classical interaction rates stemming from the quantum character for muonium, or non-Stokes-Einstein behavior.     

Rectilinear line segment intersection,layered segment trees,and dynamization

The aim of the present paper is to provide an efficient solution to the following problem: “Given a family of n rectilinear line segments in two-space report all intersections in the family with a query consisting of an arbitrary rectilinear line segment.” We provide an algorithm which takes O(nlog₂n) preprocessing time, o(nlog₂n) space and O(log₂n + k) query time, where k is the number of reported intersections. This solution serves to introduce a powerful new data structure, the layered segment tree, which is of independent interest. Second it yields, by way of recent dynamization techniques, a solution to the on-line version of the above problem, that is the operations INSERT and DELETE and QUERY with a line segment are allowed. Third it also yields a new nonscanning solution to the batched version of the above problem. Finally we apply these techniques to the problem obtained by replacing “line segment” by “rectangle” in the above problem, giving an efficient solution in this case also.