1,332 research outputs found
Two Higgs doublet models for the LHC Higgs boson data at 7 and 8 TeV
Updated LHC data on the new 126 GeV boson during the 7 and 8 TeV runnings
strengthen the standard model Higgs boson interpretation further. Through the
global analysis, we investigate whether the new particle could be one
of the scalar particles in two Higgs doublet models. Four types (Type I, II, X
and Y) are comprehensively studied. Taking the recent analysis on the
spin-parity of the new boson, we consider two scenarios: the new boson is
either the light CP-even one () or the heavy CP-even one (). It is
found that both scenarios are consistent with the new data, not only in the
parameter regions near the decoupling limit but also in other regions far from
the decoupling limit. In addition, the current data are compatible with the
possibility that the light Higgs boson is hidden in the mass window of
90-100 GeV. The diphoton or channel can provide a probe of this
possibility by the enhanced signal rates.Comment: To appear in JHE
Temperature-dependent evolutions of excitonic superfluid plasma frequency in a srong excitonic insulator candidate, TaNiSe
We investigate an interesting anisotropic van der Waals material,
TaNiSe, using optical spectroscopy. TaNiSe has been
known as one of the few excitonic insulators proposed over 50 years ago.
TaNiSe has quasi-one dimensional chains along the -axis. We have
obtained anisotropic optical properties of a single crystal TaNiSe
along the - and -axes. The measured - and -axis optical
conductivities exhibit large anisotropic electronic and phononic properties.
With regard to the -axis optical conductivity, a sharp peak near 3050
cm at 9 K, with a well-defined optical gap ( 1800
cm) and a strong temperature-dependence, is observed. With an increase
in temperature, this peak broadens and the optical energy gap closes around
325 K(). The spectral weight redistribution with respect to the
frequency and temperature indicates that the normalized optical energy gap
() is . The
temperature-dependent superfluid plasma frequency of the excitonic condensation
in TaNiSe has been determined from measured optical data. Our
findings may be useful for future research on excitonic insulators.Comment: 17 pages, 5 figure
Silicon germanium photo-blocking layers for a-IGZO based industrial display
Amorphous indium- gallium-zinc oxide (a-IGZO) has been intensively studied for the application to active matrix flat-panel display because of its superior electrical and optical properties. However, the characteristics of a-IGZO were found to be very sensitive to external circumstance such as light illumination, which dramatically degrades the device performance and stability practically required for display applications. Here, we suggest the use for silicon-germanium (Si-Ge) films grown plasmaenhanced chemical vapour deposition (PECVD) as photo-blocking layers in the a-IGZO thin film transistors (TFTs). The charge mobility and threshold voltage (V-th) of the TFTs depend on the thickness of the Si-Ge films and dielectric buffer layers (SiNX), which were carefully optimized to be similar to 200 nm and similar to 300 nm, respectively. As a result, even after 1,000 s illumination time, the V-th and electron mobility of the TFTs remain unchanged, which was enabled by the photo-blocking effect of the Si-Ge layers for a-IGZO films. Considering the simple fabrication process by PECVD with outstanding scalability, we expect that this method can be widely applied to TFT devices that are sensitive to light illumination.
Effect of Metal Door On Indoor Radio Channel
This paper reports the variation of indoor radio channel
caused by metal door. The simulation results using the Finite
Difference Time Domain (FDTD) method and measurement
results using the vector network analyzer in frequency domain
are used for the characterization of received signal strength
variation by metal door. Target frequency bands are three -
sensor band, 802.11b ISM band, and 802.11a UNII band.
From the simulation and measurement results, the effect of
door angle to the received signal strength in three frequency
bands and effect of radio frequency to variation are
investigated. And, FDTD simulation parameters for different
environments are suggested
MDR-1 gene expression is a minor factor in determining the multidrug resistance phenotype of MCF7/ADR and KB-V1 cells
AbstractThe relevance of MDR-1 gene expression to the multidrug resistance phenotype was investigated. Drug-resistant cells, KB-V1 and MCF7/ADR, constantly expressed mRNA of the MDR-1 gene and were more resistant to vinblastine and adriamycin than drug-sensitive cells, KB-3โ1 and MCF7. The drug efflux rate of KB-V1 was the same as KB-3โ1 although the MDR-1 gene was expressed in only the resistant cell. The higher intracellular drug concentration of KB-3โ1 than KB-V1 was due to the large drug influx. In the case of MCF7 and MCF7/ADR, the influx and efflux of the drug had nearly the same pattern and drug efflux was not affected by verapamil. The amount of ATP, cofactor of drug pumping activity of P-glycoprotein, was not changed by the resistance. These observations suggested that drug efflux mediated by MDR-1 gene expression was not a major determining factor of drug resistance in the present cell systems, and that the drug resistance could be derived from the change in drug uptake and other mechanisms
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