5,690 research outputs found
Spatial Interference: From Coherent To Incoherent
It is well known that direct observation of interference and diffraction
pattern in the intensity distribution requires a spatially coherent source.
Optical waves emitted from portions beyond the coherence area possess
statistically independent phases, and will degrade the interference pattern. In
this paper we show an optical interference experiment, which seems contrary to
our common knowledge, that the formation of the interference pattern is related
to a spatially incoherent light source. Our experimental scheme is very similar
to Gabor's original proposal of holography[1], just with an incoherent source
replacing the coherent one. In the statistical ensemble of the incoherent
source, each sample field produces a sample interference pattern between object
wave and reference wave. These patterns completely differ from each other due
to the fluctuation of the source field distribution. Surprisingly, the sum of a
great number of sample patterns exhibits explicitly an interference pattern,
which contains all the information of the object and is equivalent to a
hologram in the coherent light case. In this sense our approach would be
valuable in holography and other interference techniques for the case where
coherent source is unavailable, such as x-ray and electron sources.Comment: 8 pages, 5 figure
Next-to-leading order QCD predictions for the hadronic +jet production
We calculate the next-to-leading order(NLO) QCD corrections to the
production in association with a jet at hadron colliders. We study the impacts
of the complete NLO QCD radiative corrections to the integrated cross sections,
the scale dependence of the cross sections, and the differential cross sections
(, ) of the final -,
Higgs-boson and jet. We find that the corrections significantly modify the
physical observables, and reduce the scale uncertainty of the LO cross section.
Our results show that by applying the inclusive scheme with and taking , , the
K-factor is 1.15 for the process at the Tevatron,
while the K-factors for the processes and
at the LHC are 1.12 and 1.08 respectively. We conclude that to understand the
hadronic associated production, it is necessary to study the NLO QCD
corrections to production process which is part of the inclusive
production.Comment: 26 pages, 27 figures, accepted by Phys. Rev.
Threshold quantum cryptograph based on Grover's algorithm
Grover's operator in the two-qubit case can transform a basis into its
conjugated basis. A permutation operator can transform a state in the two
conjugated bases into its orthogonal state. These properties are included in a
threshold quantum protocol. The proposed threshold quantum protocol is secure
based the proof that the legitimate participators can only eavesdrop 2 bits of
3 bits operation information on one two-qubit with error probability 3/8. We
propose a scheme to detect the Trojan horse attack without destroying the legal
qubit.Comment: 7 pages, 1 figure
Automated reflection photoelasticity : digital data acquisition and use.
Automation of reflection photoelasticity has simplified the stress and strain analysis of real engineering components and reduced analysis time. However, images obtained from automated reflection photo elasticity contain noise and accuracy of the analysis will be affected by the degraded intensity images. In the present study, major sources of noise in automated reflection photoelasticity have been found to be the photoelastic coating and the electronic instrumentation. An automated reflection polariscope PSIOS developed by Patterson and Wang (1998) for the simultaneous observation and capture of four phase-stepped photo elastic images was used as an example. The majority of the noise is in the high spatial frequency domain. The zero-phase, low pass Butterworth filter was found to be the most effective and flexible smoothing method for reducing the effect of noise in the intensity images.
Results from experiments performed for assessing the ability of the PSIOS indicated that it is capable of yielding accurate results for the stress analysis of real components in both static and dynamic conditions and that it is fast and easy to use.
Full-field experimental methods are often used to validate the stress distribution generated from numerical analysis. A common practice is to plot data along a line across the maps and to include both experimental and numerical results on the same axes. This approach is used widely and usually a reasonable, quantitative conclusion can be made. However, it cannot obtain more information about the relationship between the stress maps. Another method is to compare hot spots on experimental maps to the numerical maps. If the hot spots on the two maps match well, the numerical method is considered valid. However, when designs are being optimised for weight or crack paths are being investigated, comparison of the positions of the hot spots alone will not be enough and the correlation elsewhere in the data field should be taken into account. It has been shown that fit between the stress map from an experimental method and the stress map from the numerical analysis can be represented by a statistical parameter, the scaled standard deviation. An evaluation of the method was performed using stress maps from transmission photoelasticity, thermoelasticity and the finite element method as examples. The results from experiments using a curved tiebar, a circular ring and a real engineering component in this case, a race car hub carrier indicated that the scaled standard deviation represents the fitness between the two stress maps. If the scaled standard deviation is smaller than 0.1, then the experimental map and the numerical map can be considered to be in good agreement
Next-to-leading order QCD predictions for production at LHC
We calculate the complete next-to-leading order (NLO) QCD corrections to the
production in association with a jet at the LHC. We study the impacts
of the NLO QCD radiative corrections to the integrated and differential cross
sections and the dependence of the cross section on the
factorization/renormalization scale. We present the transverse momentum
distributions of the final -, Higgs-boson and leading-jet. We find that
the NLO QCD corrections significantly modify the physical observables, and
obviously reduce the scale uncertainty of the LO cross section. The QCD
K-factors can be 1.183 and 1.180 at the and
LHC respectively, when we adopt the inclusive event selection scheme with
, and . Furthermore, we make the comparison between the two scale
choices, and , and find the scale choice seems to be more
appropriate than the fixed scale .Comment: 18 pages, 7 figure
Anti-Inflammatory Effects of Cumin Essential Oil by Blocking JNK, ERK, and NF- κ
Cumin seeds (Cuminum cyminum L.) have been commonly used in food flavoring and perfumery. In this study, cumin essential oil (CuEO) extracted from seeds was employed to investigate the anti-inflammatory effects in lipopolysaccharide- (LPS-) stimulated RAW 264.7 cells and the underlying mechanisms. A total of 26 volatile constituents were identified in CuEO by GC-MS, and the most abundant constituent was cuminaldehyde (48.773%). Mitochondrial-respiration-dependent 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) reduction assay demonstrated that CuEO did not exhibit any cytotoxic effect at the employed concentrations (0.0005–0.01%). Real-time PCR tests showed that CuEO significantly inhibited the mRNA expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX-2), interleukin- (IL-) 1, and IL-6. Moreover, western blotting analysis revealed that CuEO blocked LPS-induced transcriptional activation of nuclear factor-kappa B (NF-κB) and inhibited the phosphorylation of extracellular signal regulated kinase (ERK) and c-Jun N-terminal kinase (JNK). These results suggested that CuEO exerted anti-inflammatory effects in LPS-stimulated RAW 264.7 cells via inhibition of NF-κB and mitogen-activated protein kinases ERK and JNK signaling; the chemical could be used as a source of anti-inflammatory agents as well as dietary complement for health promotion
A Statistical Study on Photospheric Magnetic Nonpotentiality of Active Regions and Its Relationship with Flares during Solar Cycles 22-23
A statistical study is carried out on the photospheric magnetic
nonpotentiality in solar active regions and its relationship with associated
flares. We select 2173 photospheric vector magnetograms from 1106 active
regions observed by the Solar Magnetic Field Telescope at Huairou Solar
Observing Station, National Astronomical Observatories of China, in the period
of 1988-2008, which covers most of the 22nd and 23rd solar cycles. We have
computed the mean planar magnetic shear angle (\bar{\Delta\phi}), mean shear
angle of the vector magnetic field (\bar{\Delta\psi}), mean absolute vertical
current density (\bar{|J_{z}|}), mean absolute current helicity density
(\bar{|h_{c}|}), absolute twist parameter (|\alpha_{av}|), mean free magnetic
energy density (\bar{\rho_{free}}), effective distance of the longitudinal
magnetic field (d_{E}), and modified effective distance (d_{Em}) of each
photospheric vector magnetogram. Parameters \bar{|h_{c}|}, \bar{\rho_{free}},
and d_{Em} show higher correlation with the evolution of the solar cycle. The
Pearson linear correlation coefficients between these three parameters and the
yearly mean sunspot number are all larger than 0.59. Parameters
\bar{\Delta\phi}, \bar{\Delta\psi}, \bar{|J_{z}|}, |\alpha_{av}|, and d_{E}
show only weak correlations with the solar cycle, though the nonpotentiality
and the complexity of active regions are greater in the activity maximum
periods than in the minimum periods. All of the eight parameters show positive
correlations with the flare productivity of active regions, and the combination
of different nonpotentiality parameters may be effective in predicting the
flaring probability of active regions.Comment: 20 pages, 5 figures, 4 tables, accepted for publication in Solar
Physic
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