19,091 research outputs found
Momentum Distribution of Near-Zero-Energy Photoelectrons in the Strong-Field Tunneling Ionization in the Long Wavelength Limit
We investigate the ionization dynamics of Argon atoms irradiated by an
ultrashort intense laser of a wavelength up to 3100 nm, addressing the momentum
distribution of the photoelectrons with near-zero-energy. We find a surprising
accumulation in the momentum distribution corresponding to meV energy and a
\textquotedblleft V"-like structure at the slightly larger transverse momenta.
Semiclassical simulations indicate the crucial role of the Coulomb attraction
between the escaping electron and the remaining ion at extremely large
distance. Tracing back classical trajectories, we find the tunneling electrons
born in a certain window of the field phase and transverse velocity are
responsible for the striking accumulation. Our theoretical results are
consistent with recent meV-resolved high-precision measurements.Comment: 5 pages, 4 figure
NMR Search for the Spin Nematic State in LaFeAsO Single Crystal
We report a 75-As single crystal NMR investigation of LaFeAsO, the parent
phase of a pnictide high Tc superconductor. We demonstrate that spin dynamics
develop a strong two-fold anisotropy within each orthorhombic domain below the
tetragonal-orthorhombic structural phase transition at T[TO]~156 K. This
intermediate state with a dynamical breaking of the rotational symmetry freezes
progressively into a spin density wave (SDW) below T[SDW]~142 K. Our findings
are consistent with the presence of a spin nematic state below T[TO] with an
incipient magnetic order.Comment: Revised manuscript accepted for publication in Phys. Rev. Let
A characterization of compact complex tori via automorphism groups
We show that a compact Kaehler manifold X is a complex torus if both the
continuous part and discrete part of some automorphism group G of X are
infinite groups, unless X is bimeromorphic to a non-trivial G-equivariant
fibration. Some applications to dynamics are given.Comment: title changed, to appear in Math. An
Assessing the accuracy of energy turbulent diffusion dispersion correlation in a porous two-fluid model dedicated to PWR core simulations
International audienceCATHARE is a 2-fluid thermal-hydraulic code, capable of simulating thermal and mechanical phenomena occurring in the primary and secondary circuits of Pressurized Water Reactor under a wide variety of accidental situations. One of the medium-term objectives of system code CATHARE-3 is modeling a PWR core at assembly scale to simulate various accidental situations such as the loss of coolant accident (LOCA) and steam line break accident. This requires the monophasic and two-phase models that adapted to the assembly scale. However, there exists 3D models for the whole core and sub-channel scale models, which have a certain degree of validation. For more macroscopic three-dimensional models, we only have global validations without local measurements, which is necessary for the validations of each closure law's separate effects. The objective of my PhD project is improving the sub-channel scale models and developing the assembly scale models in CATHARE-3 system code with the sub-channel scale simulations and experiments results
Free nitrous acid-based nitrifying sludge treatment in a two-sludge system enhances nutrient removal from low-carbon wastewater
© 2017 Elsevier Ltd A new method to enhance nutrient removal from low carbon-wastewater was developed. The method consists of a two-sludge system (i.e., an anaerobic-anoxic-oxic reactor coupled to a nitrifying reactor (N-SBR)) and a nitrifying-sludge treatment unit using free nitrous acid (FNA). Initially, 65.1 ± 2.9% in total nitrogen removal and 69.6 ± 3.4% in phosphate removal were obtained without nitrite accumulation. When 1/16 of the nitrifying sludge was daily treated with FNA at 1.1 mg N/L for 24 h, ∼28.5% of nitrite was accumulated in the N-SBR, and total nitrogen and phosphate removal increased to 72.4 ± 3.2% and 76.7 ± 2.9%, respectively. About 67.8% of nitrite was accumulated at 1.9 mg N/L FNA, resulting in 82.9 ± 3.8% in total nitrogen removal and 87.9 ± 3.5% in phosphate removal. Fluorescence in-situ hybridization analysis showed that FNA treatment reduced the abundance of nitrite oxidizing bacteria (NOB), especially that of Nitrospira sp
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Characterization of Zika virus endocytic pathways in human glioblastoma cells
Zika virus (ZIKV) infections can cause microcephaly and neurological disorders. However, the early infection events of ZIKV in neural cells remain to be characterized. Here, by using a combination of pharmacological and molecular approaches and the human glioblastoma cell T98G as a model, we first observed that ZIKV infection was inhibited by chloroquine and NH4Cl, indicating a requirement of low intracellular pH. We further showed that dynamin is required as the ZIKV entry was affected by the specific inhibitor dynasore, small interfering RNA (siRNA) knockdown of dynamin, or by expressing the dominant-negative K44A mutant. Moreover, the ZIKV entry was significantly inhibited by chlorpromazine, pitstop2, or siRNA knockdown of clathrin heavy chain, indicating an involvement of clathrin-mediated endocytosis. In addition, genistein treatment, siRNA knockdown of caveolin-1, or overexpression of a dominant-negative caveolin mutant impacted the ZIKV entry, with ZIKV particles being observed to colocalize with caveolin-1, implying that caveola endocytosis can also be involved. Furthermore, we found that the endocytosis of ZIKV is dependent on membrane cholesterol, microtubules, and actin cytoskeleton. Importantly, ZIKV infection was inhibited by silencing of Rab5 and Rab7, while confocal microscopy showed that ZIKV particles localized in Rab5- and Rab7-postive endosomes. These results indicated that, after internalization, ZIKV likely moves to Rab5-positive early endosome and Rab7-positive late endosomes before delivering its RNA into the cytoplasm. Taken together, our study, for the first time, described the early infection events of ZIKV in human glioblastoma cell T98G
Demonstrating Additional Law of Relativistic Velocities based on Squeezed Light
Special relativity is foundation of many branches of modern physics, of which
theoretical results are far beyond our daily experience and hard to realized in
kinematic experiments. However, its outcomes could be demonstrated by making
use of convenient substitute, i.e. squeezed light in present paper. Squeezed
light is very important in the field of quantum optics and the corresponding
transformation can be regarded as the coherent state of SU(1; 1). In this
paper, the connection between the squeezed operator and Lorentz boost is built
under certain conditions. Furthermore, the additional law of relativistic
velocities and the angle of Wigner rotation are deduced as well
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