1,789 research outputs found
STUDIES OF POTENTIAL ENERGY SURFACESOF NEUTRAL, PROTONATED, NEGATIVELYCHARGED WATER CLUSTERS.
Analytical gradients of the OEPM-GTO (one electron polarizable model - Gaussian-typeorbital) and OEPM-DVR (discrete variable representation) methods have been implemented,and used in combination with the basin-hopping Monte Carlo, doubly-nudged elastic bandand eigenvector-following methods to characterize small (H2O)−n clusters. The self-consistentchargedensity-functional tight-binding (SCC-DFTB) electronic structure method has beenused in conjunction with the basin hopping Monte Carlo method to optimize low-lyingminima of (H2O)8, H+(H2O)21, and H+(H2O)22. In addition, parallel-tempering Monte Carlosimulations were used to characterize the finite temperature behavior of the (H2O)8 cluster
Dynamical mean-field theory of Hubbard-Holstein model at half-filling: Zero temperature metal-insulator and insulator-insulator transitions
We study the Hubbard-Holstein model, which includes both the
electron-electron and electron-phonon interactions characterized by and
, respectively, employing the dynamical mean-field theory combined with
Wilson's numerical renormalization group technique. A zero temperature phase
diagram of metal-insulator and insulator-insulator transitions at half-filling
is mapped out which exhibits the interplay between and . As () is
increased, a metal to Mott-Hubbard insulator (bipolaron insulator) transition
occurs, and the two insulating states are distinct and can not be adiabatically
connected. The nature of and transitions between the three states are
discussed.Comment: 5 pages, 4 figures. Submitted to Physical Review Letter
Bistable switching of a polymer-walled liquid crystal phase grating cell
We report bistable switching of a liquid crystal (LC) phase grating cell. Polymer walls are formed in an LC cell by phase separation of an LC mixture, induced by the spatial difference of the elastic energy and electric field intensity. Bistable switching of a polymer-walled liquid crystal phase grating cell could be realized by applying vertical and in-plane electric fields
One-ninth magnetization plateau stabilized by spin entanglement in a kagome antiferromagnet
The spin-1/2 antiferromagnetic Heisenberg model on a Kagome lattice is
geometrically frustrated, which is expected to promote the formation of
many-body quantum entangled states. The most sought-after among these is the
quantum spin liquid phase, but magnetic analogs of liquid, solid, and
supersolid phases may also occur, producing fractional plateaus in the
magnetization. Here, we investigate the experimental realization of these
predicted phases in the Kagome material YCu3(OD)6+xBr3-x (x=0.5). By combining
thermodynamic and Raman spectroscopic techniques, we provide evidence for
fractionalized spinon excitations and observe the emergence of a 1/9
magnetization plateau. These observations establish YCu3(OD)6+xBr3-x as a model
material for exploring the 1/9 plateau phase.Comment: to appear in Nature Physics, 33 pagses, 15 figure
Crude Extracts of Caenorhabditis elegans Suppress Airway Inflammation in a Murine Model of Allergic Asthma
Epidemiological studies suggest an inverse relationship between helminth infections and allergic disease, and several helminth-derived products have been shown to suppress allergic responses in animals. This study was undertaken to evaluate the effect of a crude extract of Caenorhabditis elegans on allergic airway inflammation in a murine model of asthma. Allergic airway inflammation was induced in BALB/c mice by sensitization with ovalbumin. The effect of the C. elegans crude extract on the development of asthma and on established asthma was evaluated by analyzing airway hyperresponsiveness, serum antibody titers, lung histology and cell counts and cytokine levels in the bronchoalveolar lavage fluid. The role of IFN-γ in the suppression of asthma by the C. elegans crude extract was investigated in IFN-γ knockout and wild-type mice. When mice were sensitized with ovalbumin together with the crude extract of C. elegans, cellular infiltration into the lung was dramatically reduced in comparison with the ovalbumin-treated group. Treatment of mice with the C. elegans crude extract significantly decreased methacholine-induced airway hyperresponsiveness and the total cell counts and levels of IL-4, IL-5 and IL-13 in the bronchoalveolar lavage fluid but increased the levels of IFN-γ and IL-12. Sensitization with the C. elegans crude extract significantly diminished the IgE and IgG1 responses but provoked elevated IgG2a levels. However, the suppressive effect of the C. elegans crude extract was abolished in IFN-γ knockout mice, and the Th2 responses in these mice were as strong as those in wild-type mice sensitized with ovalbumin. The crude extract of C. elegans also suppressed the airway inflammation associated with established asthma. This study provides new insights into immune modulation by the C. elegans crude extract, which suppressed airway inflammation in mice not only during the development of asthma but also after its establishment by skewing allergen-induced Th2 responses to Th1 responses
A New On-The-Move Integer Ambiguity Determination Method for Precise Positioning of Highly Maneuvering Ground Vehicles
In the conventional RTK (Real Time Kinematics), carrier phase measurements should be collected for several minutes in stationary state in order to determine the IA (Integer Ambiguity) in carrier phase to get the precise position. To determine the IA in motion, several OTM-RTK (On-The-Move RTK) methods have been proposed using vehicle dynamics or augmenting additional sensors. This paper presents a new OTM-RTK technique to determine the IA without aids of external sensors for precise positioning of highly maneuvering ground vehicles. In the proposed technique, the initial IA is determined fast by estimating precise position change during epochs using dual frequency carrier phase measurements. Therefore, IA determination of the proposed method is not influence by vehicle dynamics. By field experiment, performance of the proposed technique is analyzed including IA determination time according to vehicle dynamics and the number of visible SV
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