Quantitative analysis of the quark-parton distributions

A quantitative and less model-dependent analysis of the quark parton distributions is attempted. Both the valence-sea (symmetric core) model and the deformed core model are compared in detail with the present data. We find that the deformed core model is more reasonable if we assume the almost monotonous behaviour of the ratio of two valence quarks. Some properties of the distributions in the wee region, such as the rate of convergence of Adler's neutrino sum rule, Regge behaviour and J = 0 fixed pole residues, are investigated.     

Weil-Petersson geometry of Teichmüller–Coxeter complex and its finite rank property

On a Teichmüller space, the Weil-Petersson metric is known to be incomplete. Taking metric and geodesic completions result in two distinct spaces, where the Hopf-Rinow theorem is no longer relevant due to the singular behavior of the Weil-Petersson metric. We construct a geodesic completion of the Teichmüller space through the formalism of Coxeter complex with the Teichmüller space as its non-linear non-homogeneous fundamental domain. We then show that the metric and geodesic completions both satisfy a finite rank property, demonstrating a similarity with the non-compact symmetric spaces of semi-simple Lie groups.     

trans‐(4‐Amino‐2,2,6,6‐tetramethyl­piperidine‐N4)bis(pentane‐2,4‐dion­ato‐O,O′)(triphenylphosphine‐P)cobalt(III) hexafluorophosphate dichloromethane solvate

The complex cation in the title compound, [Co(C₅H₇O₂)₂(C₉H₂₀N₂)(C₁₈H₁₅P)]PF₆·CH₂Cl₂, is the first example of a Co^III complex in which a trans configuration for the coordinated monodentate phosphine and amine ligands has been confirmed by X‐ray analysis. Owing to the large steric bulkiness of the axial PPh₃ ligands influencing the interaction with the equatorial acetyl­acetonate ligands, the acetyl­acetonate planes bend away considerably from the PPh₃ ligands.     

Synthesis of single- and double-walled carbon nanotube forests on conducting metal foils

Here, we report a highly efficient growth of single-walled carbon nanotubes (SWNTs) and double-walled carbon nanotubes (DWNTs) on conducting metal foils. We found that foils made of Ni-based alloys with Cr or Fe serve as excellent substrates for SWNT (DWNT) synthesis. In significant contrast, a CNT grown on Ni, Fe foils contains a significant ratio of MWNTs. This result opens up an economical route for the mass production of SWNT (DWNT) forests and also enables the straightforward integration of CNTs into nanoelectronic devices, such as field emission displays.     

Transmission electron microscopy imaging of individual functional groups of fullerene derivatives

Mobility and reactivity of the functionalized fullerenes with pyrrolidine (C60-C3NH7) incorporated in single-wall carbon nanotubes were examined by high-resolution transmission electron microscopy. An individual functional group attached to each fullerene cage is unambiguously visualized. This provides a direct evidence for the functionalized structure on a single-molecular basis. A rotational motion of the incorporated molecules tends to occur during the observation and, consequently, each fullerene molecule is likely to stand facing its functionalized group towards the nanotube wall. A fine structure analysis of electron energy-loss spectra for the nitrogen K(1s) edge shows a considerable change in the nitrogen chemical state and suggests a strong tube-fullerene interaction.     

Polarization dependence of resonant inelastic X-ray scattering spectroscopy in correlated electron systems

Resonant inelastic X-ray scattering (RIXS) at the transition-metal K-edge is studied as a tool to detect the electronic structure in correlated electron systems. We, in particular, focus on the polarization dependence of RIXS intensity and symmetry of the electronic excitations. It is shown that by analyzing the polarization of the initial and scattered X-rays, the symmetry of the 4p orbitals are selected. Combined effects of the polarization of X-rays and the momentum transfer in the scattering are also studied.     

Metal atom catalyzed enlargement of fullerenes

A metal catalyzed enlargement of fullerenes has been demonstrated by in situ high-resolution transmission electron microscopy. It was found that carbon atoms and clusters can be continuously incorporated into a closed fullerene cage at a high temperature, leading to an increase in the diameter and consequently the formation of giant fullerene with the assist of adsorbed metal atoms. Density functional theoretical simulations indeed suggest that the activation energy for the carbon incorporation and the associated Stone-Wales transformation can be substantially reduced due to the presence of metal atoms, which should be of key importance for the fullerene growth.