561 research outputs found
Structure and Dynamics of Water at the Water-Air Interface Using First-Principles Molecular Dynamics Simulations. II. NonLocal vs Empirical van der Waals Corrections
pi(+)-pi(+) stacking of imidazolium cations enhances molecular layering of room temperature ionic liquids at their interfaces
The interfacial structure of room temperature ionic liquids (RTILs) controls many of the unique properties of RTILs, such as the high capacitance of RTILs and the efficiency of charge transport between RTILs and electrodes. RTILs have been experimentally shown to exhibit interfacial molecular layering structures over a 10 angstrom length scale. However, the driving force behind the formation of these layered structures has not been resolved. Here, we report ab initio molecular dynamics simulations of imidazolium RTIL/air and RTIL/graphene interfaces along with force field molecular dynamics simulations. We find that the pi(+)-pi(+) interaction of imidazolium cations enhances the layering structure of RTILs, despite the electrostatic repulsion. The length scales of the molecular layering at the RTIL/air and RTIL/graphene interfaces are very similar, manifesting the limited effect of the substrate on the interfacial organization of RTILs.German Science Foundation [TRR146]SCI(E)ARTICLE42850-28561
Vibrational mode frequency correction of liquid water in density functional theory molecular dynamics simulations with van der Waals correction
Trimethylamine-N-oxide: its hydration structure, surface activity, and biological function, viewed by vibrational spectroscopy and molecular dynamics simulations
Catalytic activity of graphene-covered non-noble metals governed by proton penetration in electrochemical hydrogen evolution reaction
Usefulness of Real-Time 4D Ultrasonography during Radiofrequency Ablation in a Case of Hepatocellular Carcinoma
We report a case of hepatocellular carcinoma (HCC) with chronic hepatitis C virus infection successfully treated with percutaneous radiofrequency ablation (RFA) under live four-dimensional (4D) echo guidance. A 65-year-old Japanese man had a HCC nodule in the liver S5 region 2.0 cm in diameter. We performed real-time 4D ultrasonography during RFA therapy with a LeVeen needle electrode. The echo guidance facilitated an accurate approach for the needle puncture. The guidance was also useful for confirming whether an adequate safety margin for the nodule had been obtained. Thus real-time 4D ultrasonography echo technique appears to provide safe guidance of RFA needles via accurate targeting of HCC nodules, thereby allowing real-time visualization when combined with echo contrast. Furthermore the position of the needle in a still image was confirmed in every area using a multiview procedure
The surface roughness, but not the water molecular orientation varies with temperature at the water-air interface
The dielectric function profile across the water interface through surface-specific vibrational spectroscopy and simulations
AGN feedback and gas mixing in the core of NGC 4636
Chandra observations of NGC 4636 show disturbances in the galaxy X-ray halo,
including arm-like high surface brightness features (tentatively identified as
AGN driven shocks) and a possible cavity on the west side of the galaxy core.
We present Chandra and XMM spectral maps of NGC 4636 which confirm the presence
of the cavity and show it to be bounded by the arm features. The maps also
reveal a ~15 kpc wide plume of low temperature, high abundance gas extending
25-30 kpc to the southwest of the galaxy. The cavity appears to be embedded in
this plume, and we interpret the structure as being entrained gas drawn out of
the galaxy core during previous episodes of AGN activity. The end of the plume
is marked by a well defined edge, with significant falls in surface brightness,
temperature and abundance, indicating a boundary between galaxy and
group/cluster gas. This may be evidence that as well as preventing gas cooling
through direct heating, AGN outbursts can produce significant gas mixing,
disturbing the temperature structure of the halo and transporting metals out
from the galaxy into the surrounding intra-group medium.Comment: 4 Pages, 2 colour figures, accepted for publication in ApJ Letters.
Version with high quality images at
http://hea-www.harvard.edu/~ejos/files/N4636_hires.pd
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