Centrality dependence of charged-hadron transverse-momentum spectra in d+Au collisions at sqrt[s(NN)]=200 GeV

We have measured transverse momentum distributions of charged hadrons produced in d+Au collisions at sqrt[s(NN)]=200 GeV. The spectra were obtained for transverse momenta 0.25相似文献   

Synthesis and crystallographic characterization of a ‘palladadehydrobenzo[19]annulene’

The trans-palladium bis(σ-acetylide) complex (Et₃P)₂Pd(C₃₀H₁₂) (2) was synthesized from hexane 4 in 77% yield via a simple three-step process. The X-ray crystal structure of 2 shows a strained and warped annulenic core upon insertion of the organometallic fragment. UV-vis data of the molecule suggest limited electronic delocalization throughout the metallacycle.     

Hydrate and Alcoholate Forms of Phosphomolybdic Heteropolyacid and Their Formation under Conditions of Isothermal Sorption of Water,Methanol, and Ethanol Vapors

Reaction of water, methanol, and ethanol vapors with a solid phosphomolybdic acid at room temperature is accompanied by formation of bulk hydrates and alcoholates. The reaction involves several stages which are readily detected by the sorption and desorption isotherms. The formation of alcoholates causes loosening of the acid lattice, thus favoring much more active initial sorption of alcohols, compared with water, and liquefaction once H₃PMo₁₂O₄₀·11.5CH₃OH and H₃PMo₁₂O₄₀·14.7C₂H₅OH compositions are attained.     

Key Word Index of Volume 36 – 2001

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Key Word Index of Volume 36 – 2001     

Baryon rapidity loss in relativistic Au + Au collisions

An excitation function of proton rapidity distributions for different centralities is reported from AGS Experiment E917 for Au+Au collisions at 6, 8, and 10.8 GeV/nucleon. The rapidity distributions from peripheral collisions have a valley at midrapidity which smoothly change to distributions that display a broad peak at midrapidity for central collisions. The mean rapidity loss increases with increasing beam energy, whereas the fraction of protons consistent with isotropic emission from a stationary source at midrapidity decreases with increasing beam energy. The data suggest that the stopping is substantially less than complete at these energies.     

Jamming of Granular Flow in a Two-Dimensional Hopper

We study experimentally the jamming phenomenon of granular flow of monodisperse disks of D = 5 mm diameter in a two-dimensional hopper with opening R. The jamming probability J(d) is measured where d identical withR/D. We found that J(d) decreases from 1 to zero when d increases from 2 to 5. From observing the disk configurations of the arch in the jamming events, the jamming probability can be explained quantitatively by treating the arch as the trajectory of a restricted random walker.     

Ribbon tile invariants

Let be a finite set of tiles, and a set of regions tileable by . We introduce a tile counting group as a group of all linear relations for the number of times each tile can occur in a tiling of a region . We compute the tile counting group for a large set of ribbon tiles, also known as rim hooks, in a context of representation theory of the symmetric group.

The tile counting group is presented by its set of generators, which consists of certain new tile invariants. In a special case these invariants generalize the Conway-Lagarias invariant for tromino tilings and a height invariant which is related to computation of characters of the symmetric group.

The heart of the proof is the known bijection between rim hook tableaux and certain standard skew Young tableaux. We also discuss signed tilings by the ribbon tiles and apply our results to the tileability problem.

     

Biomolecules-carbon nanotubes doped conducting polymer nanocomposites and their sensor application

A simple method for preparing bio-functionalized soluble single-walled carbon nanotubes (SWNTs) is described. Different proteins such as bovine serum albumin (BSA), cytochrome c and horseradish peroxidase (HRP) were used to solubilize low functionality SWNTs in water aided by sonication. The unbound proteins were removed by column chromatography and the SWNT-protein conjugate was used as the sole anionic dopant in electropolymerization of polypyrrole from polymerization solution at pH above the isoelectric point of the protein to provide a negative charge. The morphology of the polypyrrole with SWNT-protein dopant was found to be three-dimensional and fibrous with wide open interlocking pores in contrast to smooth and cauliflower-like for chloride doped polypyrrole. Enhanced sensor performance was demonstrated for hydrogen peroxide detection on polypyrrole/SWCNT-HRP nanocomposites modified electrode. Such nanocomposites can be potentially applied for other biosensor and bio-fuel cell applications.