4,707 research outputs found
Associated production of a neutral top-Higgs with a heavy-quark pair in the \gamma\gamma collisions at ILC
We have studied the associated production processes of a neutral top-Higgs in
the topcolor assisted technicolor model with a pair of heavy quarks in
\gamma\gamma collisions at the International Linear Collider (ILC). We find
that the cross section for t\bar{t}h_t in \gamma\gamma collisions is at the
level of a few fb with the c.m. energy \sqrt{s}=1000 GeV, which is consistent
with the results of the cross section of t\bar{t}H in the standard model and
the cross section of t\bar{t}h in the minimal supersymmetric standard modeland
the little Higgs models. It should be distinct that hundreds of to thousands of
h_t per year can be produced at the ILC, this process of \gamma\gamma \to
t\bar{t}h_t is really interesting in testing the standard model and searching
the signs of technicolor.Comment: 4 pages, 4 figures, some references are adde
Effect of Molecular Structure Modification and Nano-Doping on Charge Transportation of Polyimide Films for Winding Insulation
Polyimide (PI) is widely employed as winding insulation in high voltage devices, such as extra-high voltage electric reactor and inverter-fed motor. The injection and accumulation of charges on the surface of PI films will lead to electrical field distortion and reduced lifespan of winding insulation, especially for the operation environment of high temperature and high voltage. This chapter focuses on effects of surface molecular modification and nanoparticles on dynamic characteristics of surface charge and space charge of pure PI films, including three sections. The effect of molecular structure on the surface charge dynamics of PI films was studied firstly. The chapter investigated that how molecular structure affects surface charge of polyimide nanocomposite films. Furthermore, the effect of surface molecular modification on space charge characteristics of multilayer PI films was researched. The results illustrate that surface molecular modification and nanoparticles can comprehensively suppress space charge accumulation and improve dielectric property
Breast cancer imaging by microwave-induced thermoacoustic tomography
We report a preliminary study of breast cancer imaging by microwave-induced thermoacoustic tomography. In this study, we built a prototype of breast cancer imager based on a circular scan mode. A 3-GHz 0.3~0.5-μs microwave is used as the excitation energy source. A 2.25-MHz ultrasound transducer scans the thermoacoustic signals. All the measured data is transferred to a personal computer for imaging based on our proposed back-projection reconstruction algorithms. We quantified the line spread function of the imaging system. It shows the spatial resolution of our experimental system reaches 0.5 mm. After phantom experiments demonstrated the principle of this technique, we moved the imaging system to the University of Texas MD Anderson Cancer Center to image the excised breast cancer specimens. After the surgery performed by the physicians at the Cancer Center, the excised breast specimen was placed in a plastic cylindrical container with a diameter of 10 cm; and it was then imaged by three imaging modalities: radiograph, ultrasound and thermoacoustic imaging. Four excised breast specimens have been tested. The tumor regions have been clearly located. This preliminary study demonstrated the potential of microwave-induced thermoacoustic tomography for applications in breast cancer imaging
Surface glycoproteins of influenza A H3N2 virus modulate virus replication in the respiratory tract of ferrets
AbstractThe hemagglutinin (HA) genes of the influenza A H3N2 subtype viruses isolated from 1968 to 2010 have evolved substantially but their neuraminidase (NA) genes have been relatively less divergent. The H3N2 viruses isolated since 1995 were found to replicate in the lower respiratory tract of ferrets less efficiently than the earlier isolates. To evaluate whether the HA or/and NA or the internal protein gene segments of the H3N2 virus affected viral replication in the respiratory tract of ferrets, recombinant A/California/07/2004 (CA04) (H3N2) virus and its reassortants that contained the same CA04 internal protein gene segments and the HA and/or NA of A/Udorn/309/1972 (UD72) or A/Wuhan/359/1995 (WH95) H3N2 viruses were generated and evaluated for their replication in the respiratory tract of ferrets. All the reassortant viruses replicated efficiently in the upper respiratory tract of ferrets, but their replication in the lower respiratory tract of ferrets varied. In contrast to the UD72-HA reassortant virus that replicated efficiently in the lungs of ferrets, the virus with the WH95-HA or the CA04-HA either replicated modestly or did not replicate in the lungs of ferrets. The reassortants with the WH95-HA and UD72-NA or CA04-NA had the tendency to lose a N-linked glycosylation site at residue 246 in the HA, resulting in viral lung titer of 100-fold higher than the virus with the HA and NA from WH95. The UD72-NA had the highest neuraminidase activity and increased viral replication by up to 100-fold in tissue culture cells during early infection. Thus, our data indicate that both the HA and NA glycoproteins play important roles in viral replication of the H3N2 influenza virus in ferrets
Optical Design of a Solar Dish Concentrator Based on Triangular Membrane Facets
The design of a solar dish concentrator is proposed based on triangular membrane facets for space power applications. The facet concentrator approximates a parabolic surface supported by a deployable perimeter truss structure, which originates from a large aperture space antenna. For optimizing the number of facets rows and focal-diameter ratio of the concentrator, Monte Carlo ray-tracing method is utilized to determine optical performance of the concentrator, and the system root-mean-square (RMS) deviation is considered in this design procedure. A 600-facet concentrator with focal-diameter ratio of 1.1 will achieve 83.63% of radiative collection efficiency over a 15 cm radius disk located in the focal plane, with a mean solar concentration ratio exceeding 300. The study in this paper is helpful for the development of the membrane facet concentrator
Quantum Discord for Investigating Quantum Correlations without Entanglement in Solids
Quantum systems unfold diversified correlations which have no classical
counterparts. These quantum correlations have various different facets. Quantum
entanglement, as the most well known measure of quantum correlations, plays
essential roles in quantum information processing. However, it has recently
been pointed out that quantum entanglement cannot describe all the
nonclassicality in the correlations. Thus the study of quantum correlations in
separable states attracts widely attentions. Herein, we experimentally
investigate the quantum correlations of separable thermal states in terms of
quantum discord. The sudden change of quantum discord is observed, which
captures ambiguously the critical point associated with the behavior of
Hamiltonian. Our results display the potential applications of quantum
correlations in studying the fundamental properties of quantum system, such as
quantum criticality of non-zero temperature.Comment: 4 pages, 4 figure
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