31,337 research outputs found
Calculable One-Loop Contributions to S and T Parameters in the Gauge-Higgs Unification
We investigate the one-loop contributions to S and T oblique parameteres in
gauge-Higgs unification. We show that these parameters are finite in five
dimensional space-time, but are divergent in more than five dimensions.
Remarkably, however, we find that a particular linear combination of S and T
parameters, S - 4 \cos \theta_{W} T, becomes finite for six dimensional
space-time, though each of these parameters is divergent. This is because, in
the Gauge-Higgs unification scenario, the operators relevant for S and T
parameters are not independent, but are included in a unique higher dimensional
gauge invariant operator. Thus the predictable linear combination is model
independent, irrespectibly of the detail of the matter content.Comment: 25 pages, 1 eps file, minor corrections, version to appear in PR
Flavor Mixing in the Gauge-Higgs Unification
Gauge-Higgs unification is the fascinating scenario solving the hierarchy
problem without supersymmetry. In this scenario, the Standard Model (SM) Higgs
doublet is identified with extra component of the gauge field in higher
dimensions and its mass becomes finite and stable under quantum corrections due
to the higher dimensional gauge symmetry. On the other hand, Yukawa coupling is
provided by the gauge coupling, which seems to mean that the flavor mixing and
CP violation do not arise at it stands. In this talk, we discuss that the
flavor mixing is originated from simultaneously non-diagonalizable bulk and
brane mass matrices. Then, this mechanism is applied to various flavor changing
neutral current (FCNC) processes via Kaluza-Klein (KK) gauge boson exchange at
tree level and constraints for compactification scale are obtained.Comment: 5 pages, prepared for the proceedings of the International Workshop
on Grand Unified Theories (GUT2012) held at Yukawa Institute for Theoretical
Physics, March 15-17 2012, Kyoto, Japa
Oral cancer secretome: Identification of cancer-associated proteins
This study aims to identify cancer-associated proteins in the secretome of oral cancer cell lines. We have successfully established four primary cell cultures of normal cells with a limited lifespan without human telomerase reverse transcriptase (hTERT) immortalization. The secretome of these primary cell cultures were compared with that of oral cancer cell lines using 2DE. Thirty five protein spots were found to have changed in abundance. Unambiguous identification of these proteins was achieved by MALDI TOF/TOF. In silico analysis predicted that 24 of these proteins were secreted via classical or nonclassical mechanisms. The mRNA expression of six genes was found to correlate with the corresponding protein abundance. Ingenuity Pathway Analysis (IPA) core analysis revealed that the identified proteins were relevant in, and related to, cancer development with likely involvements in tumor growth, metastasis, hyperproliferation, tumorigenesis, neoplasia, hyperplasia, and cell transformation. In conclusion, we have demonstrated that a comparative study of the secretome of cancer versus normal cell lines can be used to identify cancer-associated proteins.Article Link: http://onlinelibrary.wiley.com/doi/10.1002/elps.201300126/abstrac
Finite temperature Casimir pistons for electromagnetic field with mixed boundary conditions and its classical limit
In this paper, the finite temperature Casimir force acting on a
two-dimensional Casimir piston due to electromagnetic field is computed. It was
found that if mixed boundary conditions are assumed on the piston and its
opposite wall, then the Casimir force always tends to restore the piston
towards the equilibrium position, regardless of the boundary conditions assumed
on the walls transverse to the piston. In contrary, if pure boundary conditions
are assumed on the piston and the opposite wall, then the Casimir force always
tend to pull the piston towards the closer wall and away from the equilibrium
position. The nature of the force is not affected by temperature. However, in
the high temperature regime, the magnitude of the Casimir force grows linearly
with respect to temperature. This shows that the Casimir effect has a classical
limit as has been observed in other literatures.Comment: 14 pages, 3 figures, accepted by Journal of Physics
Fourth-order discrete-time variable centre frequency bandpass sigma-delta modulator
Copyright © 2006 IEEEA design for a variable centre frequency bandpass sigma-delta modulator is presented. The modulator is based on a tunable discrete-time resonator using only one control parameter. The noise transfer function of the modulator is controlled by a 4-bit digital signal, which provides nine different centre frequencies distributed between 0.1-0.4 normalized frequencies. The measurement results show a stable modulator at all centre frequenciesY. Zhu, S.F. Al-Sarawi, C. C. Lim, and M.J. Liebel
Combined Effect of Latex and Crumb Rubber on Mechanical Properties of Concrete for Railway Application
Crumb rubber incorporation is widely deemed to deteriorate the compressive strength of concrete. One of the dominant reasons for this strength reduction is known as the inferior bonding or weak interfacial transition zones (ITZ) between the crumb rubber and hardened cement paste. While Styrene-butadiene (SBR) latex is being used as a bonding agent in concrete manufacturing, the SBR latex usage holds the potential to compensate for the strength reduction from crumb rubber incorporation. This study focuses on evaluating the sole and combined effect of crumb rubber and SBR latex on the compressive strength, one optimum combination of latex modified rubberised mix (LMCRC) that had achieved 55.5 MPa of 28 days characteristic strength was chosen to compare its impact resistance and stress-strain response to a plain concrete (PC) with similar characteristic strength. Experimental results showed both crumb rubber and SBR latex incorporation induced a compressive strength reduction in the concrete. The optimum latex modified rubberised mix with w/c of 0.32, crumb rubber replacement of 20kg/m3, and 3% latex additives had outperformed the control mix with w/c ratio of 0.38 by 66.7% and 293% in the 400mm span impact test and 200mm span impact test, respectively. Besides, the latex modified rubberised mix showed higher Poisson’s ratio, and higher compressive strain which indicates more ductile behaviour as compared to the plain concrete
Combined Effect of Latex and Crumb Rubber on Mechanical Properties of Concrete for Railway Application
Crumb rubber incorporation is widely deemed to deteriorate the compressive strength of concrete. One of the dominant reasons for this strength reduction is known as the inferior bonding or weak interfacial transition zones (ITZ) between the crumb rubber and hardened cement paste. While Styrene-butadiene (SBR) latex is being used as a bonding agent in concrete manufacturing, the SBR latex usage holds the potential to compensate for the strength reduction from crumb rubber incorporation. This study focuses on evaluating the sole and combined effect of crumb rubber and SBR latex on the compressive strength, one optimum combination of latex modified rubberised mix (LMCRC) that had achieved 55.5 MPa of 28 days characteristic strength was chosen to compare its impact resistance and stress-strain response to a plain concrete (PC) with similar characteristic strength. Experimental results showed both crumb rubber and SBR latex incorporation induced a compressive strength reduction in the concrete. The optimum latex modified rubberised mix with w/c of 0.32, crumb rubber replacement of 20kg/m3, and 3% latex additives had outperformed the control mix with w/c ratio of 0.38 by 66.7% and 293% in the 400mm span impact test and 200mm span impact test, respectively. Besides, the latex modified rubberised mix showed higher Poisson’s ratio, and higher compressive strain which indicates more ductile behaviour as compared to the plain concrete
Metal oxide-graphene field-effect transistor: interface trap density extraction model
A simple to implement model is presented to extract interface trap density of graphene field effect transistors. The presence of interface trap states detrimentally affects the device drain current-gate voltage relationship Ids-Vgs. At the moment, there is no analytical method available to extract the interface trap distribution of metal-oxide-graphene field effect transistor (MOGFET) devices. The model presented here extracts the interface trap distribution of MOGFET devices making use of available experimental capacitance-gate voltage Ctot-Vgs data and a basic set of equations used to define the device physics of MOGFET devices. The model was used to extract the interface trap distribution of 2 experimental devices. Device parameters calculated using the extracted interface trap distribution from the model, including surface potential, interface trap charge and interface trap capacitance compared very well with their respective experimental counterparts. The model enables accurate calculation of the surface potential affected by trap charge. Other models ignore the effect of trap charge and only calculate the ideal surface potential. Such ideal surface potential when used in a surface potential based drain current model will result in an inaccurate prediction of the drain current. Accurate calculation of surface potential that can later be used in drain current model is highlighted as a major advantage of the model
Enhanced five-port ring circuit reflectometer for synthetic breast tissue dielectric determination
In this study,a Six-port Reflectometer (SPR) with dielectric probe sensor is used to predict relative dielectric,εr of normal and tumorous breast tissue in frequency range from 2.34GHz to 3.0GHz. Other than that,a superstrate with an exterior copper layer is overlaid on the surface of a primitive Five-port Ring Circuit (FPRC),which is also a denominated,enhanced superstrate FPRC. It is the main component of the SPR and is presented in this paper as well. The enhanced superstrate FPRC is capable of improving its operating bandwidth by 26% and shifting the operating centre frequency to a lower value without increasing circuit physical size. The detailed design and characteristics of the FPRC are described here. In addition,the enhanced superstrate FPRC is integrated into the SPR for one-port reflection coefficient measurement. The measurement using the SPR is benchmarked with Agilent’s E5071C Vector Network Analyzer (VNA) for one-port reflection coefficient. Maximum absolute mean error of the linear magnitude and phase measurements are recorded to be 0.03 and 5.50°,respectively. In addition,maximum absolute error of the predicted dielectric and loss factor are 1.77 and 0.61,respectively
Resonant Coherent Phonon Spectroscopy of Single-Walled Carbon Nanotubes
Using femtosecond pump-probe spectroscopy with pulse shaping techniques, one
can generate and detect coherent phonons in chirality-specific semiconducting
single-walled carbon nanotubes. The signals are resonantly enhanced when the
pump photon energy coincides with an interband exciton resonance, and analysis
of such data provides a wealth of information on the chirality-dependence of
light absorption, phonon generation, and phonon-induced band structure
modulations. To explain our experimental results, we have developed a
microscopic theory for the generation and detection of coherent phonons in
single-walled carbon nanotubes using a tight-binding model for the electronic
states and a valence force field model for the phonons. We find that the
coherent phonon amplitudes satisfy a driven oscillator equation with the
driving term depending on photoexcited carrier density. We compared our
theoretical results with experimental results on mod 2 nanotubes and found that
our model provides satisfactory overall trends in the relative strengths of the
coherent phonon signal both within and between different mod 2 families. We
also find that the coherent phonon intensities are considerably weaker in mod 1
nanotubes in comparison with mod~2 nanotubes, which is also in excellent
agreement with experiment.Comment: 21 pages, 22 figure
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