Porous graphenes: two-dimensional polymer synthesis with atomic precision

http://physics.gsu.edu/dhamala/publications/NeuroImage_Dhamala08.pdf

Analyzing information flow in brain networks with nonparametric Granger causality.

The conducting surface states of 3D topological insulators are two-dimensional. In an analogous way, the edge states of 2D topological insulators are one-dimensional. Direct evidence of this one-dimensionality is now presented, by means of scanning tunnelling spectroscopy, for bismuth bilayers—one of the first theoretically predicted 2D topological insulators.

/pdf/one-dimensional-topological-edge-states-of-bismuth-bilayers-4x07m5atdd.pdf

One-dimensional topological edge states of bismuth bilayers

Driven by applications in chemical sensing, biological imaging and material characterisation, Raman spectroscopies are attracting growing interest from a variety of scientific disciplines The Raman effect originates from the inelastic scattering of light, and it can directly probe vibration/rotational-vibration states in molecules and materials Despite numerous advantages over infrared spectroscopy, spontaneous Raman scattering is very weak, and consequently, a variety of enhanced Raman spectroscopic techniques have emerged These techniques include stimulated Raman scattering and coherent anti-Stokes Raman scattering, as well as surface- and tip-enhanced Raman scattering spectroscopies The present review provides the reader with an understanding of the fundamental physics that govern the Raman effect and its advantages, limitations and applications The review also highlights the key experimental considerations for implementing the main experimental Raman spectroscopic techniques The relevant data analysis methods and some of the most recent advances related to the Raman effect are finally presented This review constitutes a practical introduction to the science of Raman spectroscopy; it also highlights recent and promising directions of future research developments

/pdf/raman-techniques-fundamentals-and-frontiers-310lvxqn81.pdf

Raman Techniques: Fundamentals and Frontiers

Carbon nanotube growth mechanism switches from tip- to base-growth with decreasing catalyst particle size

The masses of six neutron-deficient rare holmium and thulium isotopes close to the proton drip line were determined with the SHIPTRAP Penning trap mass spectrometer. For the first time the masses of the proton-unbound isotopes {sup 144,145}Ho and {sup 147,148}Tm were directly measured. The proton separation energies were derived from the measured mass values and compared to predictions from mass formulas. The new values of the proton separation energies are used to determine the location of the proton drip line for holmium and thulium more accurately.

First Penning Trap Mass Measurements beyond the Proton Drip Line

We are investigating a new concept of a buffer gas filled ion cooler built from single radio frequency (RF) ring electrodes. In such a ring electrode structure, the RF potential generates an average repelling short-range force perpendicular to the electrode surfaces. Due to the composition of single rings, the shape of the cooling channel can easily and smoothly be varied, and hence also the direction of the RF forces. As a result, the angular acceptance can be increased by a factor of two in comparison to the maximum acceptance for the present RF quadrupole coolers.

P. G. Thirolf

Papers

First Penning Trap Mass Measurements beyond the Proton Drip Line

A new concept for cooling low-energy ion beams