726 research outputs found
Dynamic Polarization Effects in Ion Channeling Through Single-Well Carbon Nanotubs
Ion channeling through a single-wall carbon nanotube is simulated by solving Newton’s equations for ion motion at intermediate energies, under the action of both the surface-atom repulsive forces and the polarization forces due to the dynamic perturbation of the nanotube electrons. The atomic repulsion is described by a continuum potential based on the Thomas-Fermi-Moliere model, whereas the dynamic polarization of the nanotube electrons is described by a two-dimensional hydrodynamic model, giving rise to the transverse dynamic image force and the longitudinal stopping force. In the absence of centrifugal forces, a balance between the image force and the atomic repulsion is found to give rise to ion trajectories which oscillate over peripheral radial regions in the nanotube, provided the ion impact position is not too close to the nanotube wall, the impact angle is sufficiently small, and the incident speed is not too high. Otherwise, the ion is found to oscillate between the nanotube walls, passing over a local maximum of the potential in the center of the nanotube, which results from the image interaction. The full statistical analysis of 103 ion trajectories has been made to further demonstrate the actual effect of dynamic polarization on the ion channeling
Effects of Exogenous Cellulase Source on In Vitro Fermentation Characteristics and Methane Production of Crop Straws and Grasses
In vitro fermentation experiments were conducted to investigate the effects of 3 sources of
exogenous cellulase products (EC) at 4 dose rates (DR) (0, 12, 37 and 62 IU/g of DM) on degradation
of forage and methane production by mixed rumen micro-organisms of goats. The maximum gas
production (Vf) of grasses was higher (P<0.001) in Neocallimastix patriciarum (NP) group than those in
Trichoderma reesei (TR) and Trichoderma longibrachiatum (TL) groups. Quadratic increases in dry
matter degradation (DMD) of forage and neutral detergent fiber (NDFD) of straw were observed for all
EC, with optimum DR in the low range. Supplementation of EC originated from TR and NP increased
(P<0.001) DMD of forage compared to that from TL. Addition of EC originated from TR and NP also
decreased pH value, ammonia nitrogen (NH3-N) and methane (CH4) production compared to that from
TL. Quadratic decreases in pH value, NH3-N and CH4 of forage were noted for EC of TR and NP, and
with optimum DR in the low range. For short chain fatty acid, the EC of NP increased total volatile
fatty acid (TVFA) and acetate concentration and the ratio of acetate to propionate of forage compared
with EC of TL and TR, and with optimum DR in the low to medium range. It was concluded that the
source of EC differed in fiber degradation and methane emission, and with optimum DR of TR in the
low range (from 12 to 37 U/g DM) in improving fiber degradation and decreasing methane emission
Advanced analytical techniques in ELECTROACROSS. Matrix characterization and monitoring electrokinetic processes in recovery, remediation and conservation:Abstract of poster presentation
The Charge Form Factor of the Neutron from the Reaction \pol{2H}(\pol{e},e'n)p
We report on the first measurement of spin-correlation parameters in
quasifree electron scattering from vector-polarized deuterium. Polarized
electrons were injected into an electron storage ring at a beam energy of
720~MeV. A Siberian snake was employed to preserve longitudinal polarization at
the interaction point. Vector-polarized deuterium was produced by an atomic
beam source and injected into an open-ended cylindrical cell, internal to the
electron storage ring. The spin correlation parameter A^V_{ed} was measured for
the reaction \pol{2H}(\pol{e},e'n)p at a four-momentum transfer squared of 0.21
(GeV/c)^2 from which a value for the charge form factor of the neutron was
extracted.Comment: 4 pages, 5 file
Electrokinetics across disciplines and continents: an integrated approach to finding new strategies for sustainable development - ELECTROACROSS:Abstract of poster presentation
Probing the function of neuronal populations : combining micromirror-based optogenetic photostimulation with voltage-sensitive dye imaging
Author Posting. © The Author(s), 2012. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Neuroscience Research 75 (2013): 76-81, doi:10.1016/j.neures.2012.11.006.Recent advances in our understanding of brain function have come from using light to either
control or image neuronal activity. Here we describe an approach that combines both
techniques: a micromirror array is used to photostimulate populations of presynaptic
neurons expressing channelrhodopsin-2, while a red-shifted voltage-sensitive dye allows
optical detection of resulting postsynaptic activity. Such technology allowed us to control the
activity of cerebellar interneurons while simultaneously recording inhibitory responses in
multiple Purkinje neurons, their postsynaptic targets. This approach should substantially
accelerate our understanding of information processing by populations of neurons within
brain circuits.This work was
supported by a Grass Foundation fellowship, National Institutes of Health (NIH grant: R01
EB001963), Duke‐NUS Signature Research Program (SRP) block grant, CRP grant from
the National Research Foundation (Singapore) and by the World Class Institute (WCI)
Program of the National Research Foundation of Korea (NRF) funded by the Ministry of
Education, Science and Technology of Korea (MEST) (NRF Grant Number: WCI 2009-003)
Measurements of the observed cross sections for exclusive light hadrons containing at , 3.650 and 3.6648 GeV
By analyzing the data sets of 17.3, 6.5 and 1.0 pb taken,
respectively, at , 3.650 and 3.6648 GeV with the BES-II
detector at the BEPC collider, we measure the observed cross sections for
, , ,
and at the three energy
points. Based on these cross sections we set the upper limits on the observed
cross sections and the branching fractions for decay into these
final states at 90% C.L..Comment: 7 pages, 2 figure
Partial wave analysis of J/\psi \to \gamma \phi \phi
Using events collected in the BESII detector, the
radiative decay is
studied. The invariant mass distribution exhibits a near-threshold
enhancement that peaks around 2.24 GeV/.
A partial wave analysis shows that the structure is dominated by a
state () with a mass of
GeV/ and a width of GeV/. The
product branching fraction is: .Comment: 11 pages, 4 figures. corrected proof for journa
- …