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.

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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

SHIPTRAP is an ion trap facility coupled to the in-flight separator SHIP at GSI. Ion traps are particularly interesting devices since they allow one to store the species of interest for an extended time under well-defined conditions, including small phase space and high purity. These are ideal prerequisites for fundamental investigations, like for example nuclear spectroscopy, nuclear fission studies or optical spectroscopy [1]. In this contribution we focus on the status of the mass measurement program on transuranium nuclei. The complete SHIPTRAP apparatus is presently being set up. It consists of three major components which serve different functions. In the following these elements are explained and the status is given.

Status of the SHIPTRAP facility at GSI

The SHIPTRAP facility at GSI will deliver cooled and purified ion bunches of heavy radionuclides produced at SHIP. A key element is the RFQ buncher. A buncher consists of four segmented rods to which rf voltages are applied to create a transversely focusing field. An electric DC field along the axis controls the longitudinal energy of the ions. The RFQ is filled with gas so that the energy of the ions entering into the linear trap will be reduced due to collisions with the gas and they will be confined at the end of the system. The ions can be extracted in a pulsed mode in bunches with high phase space density and can be delivered to a high vacuum region.

D. Habs

Papers

First Penning Trap Mass Measurements beyond the Proton Drip Line

Status of the SHIPTRAP facility at GSI

A radiofrequency quadrupole (RFQ) for accumulation and cooling of heavy radionuclides at the SHIPTRAP facility at GSI