913 research outputs found
Polarized Neutron Inelastic Scattering Study of the Anisotropic Magnetic Fluctuations in the Quasi-1D Ising-like Antiferromagnet TlCoCl
Polarized neutron inelastic scattering experiments have been carried out in
the quasi-1D Ising-like antiferromagnet TlCoCl. We observed the
longitudinal magnetic fluctuation for the spin-wave
excitation continuum, which has not been observed in the unpolarized neutron
inelastic scattering experiments of the quasi-1D Ising-like antiferromagnets
CsCoCl and TlCoCl so far, together with the transverse magnetic
fluctuation . We compared both obtained intensities of
and with the perturbation theory from
the pure Ising limit by Ishimura and Shiba, and a semi-quantitative agreement
was found.Comment: 5 pages, 5 figures, jpsj2.cls, to be published in J. Phys. Soc. Jpn.
Vol. 75 (2006) No.
Stationary Closed Strings in Five-dimensional Flat Spacetime
We investigate stationary rotating closed Nambu-Goto strings in
five-dimensional flat spacetime. The stationary string is defined as a
worldsheet that is tangent to a timelike Killing vector. Nambu-Goto equation of
motion for the stationary string is reduces to the geodesic equation on the
orbit space of the isometry group action generated by the Killing vector. We
take a linear combination of a time-translation vector and space-rotation
vectors as the Killing vector, and explicitly construct general solutions of
stationary rotating closed strings in five-dimensional flat spacetime. We show
a variety of their configurations and properties.Comment: 22 pages, 17 figure
Heavy Higgs at Tevatron and LHC in Universal Extra Dimension Models
Universal Extra Dimension (UED) models tend to favor a distinctively heavier
Higgs mass than in the Standard Model (SM) and its supersymmetric extensions
when the Kaluza-Klein (KK) scale is not much higher than the electroweak one,
which we call the weak scale UED, in order to cancel the KK top contributions
to the T-parameter. Such a heavy Higgs, whose production through the gluon
fusion process is enhanced by the KK top loops, is fairly model independent
prediction of the weak scale UED models regardless of the brane-localized mass
structure at the ultraviolet cutoff scale. We study its cleanest possible
signature, the Higgs decay into a Z boson pair and subsequently into four
electrons and/or muons, in which all the four-momenta of the final states can
be measured and both the Z boson masses can be checked. We show that the weak
scale UED model may account for the 2sigma excess of this event at ATLAS at the
ZZ pair invariant mass around 250GeV, at which scale SM background is
sufficiently small and the SM Higgs predicts too few events. We have also
studied the Higgs mass 500GeV (and also 700GeV with \sqrt{s}=14TeV) and have
found that we can observe significant resonance with the integrated luminosity
10fb^{-1} for six dimensional UED models.Comment: (v1) 36 pages, 9 figures, 6 tables; (v2) Accepted for publication in
Phys. Rev. D, factor 2 error in (93) corrected, comments and references
added, figures redrawn; (v3) Minor changes including typo corrections in
eq.(15), final version appearing in PR
A topology optimization method in rarefied gas flow problems using the Boltzmann equation
This paper presents a topology optimization method in rarefied gas flow problems to obtain the optimal structure of a flow channel as a configuration of gas and solid domains. In this paper, the kinetic equation, the governing equation of rarefied gas flows, is extended over the entire design domain including solid domains assuming the solid as an imaginary gas for implicitly handling the gas-solid interfaces in the optimization process. Based on the extended equation, a 2D flow channel design problem is formulated, and the design sensitivity is obtained based on the Lagrange multiplier method and adjoint variable method. Both the rarefied gas flow and the adjoint flow are computed by a deterministic method based on a finite discretization of the molecular velocity space, rather than the DSMC method. The validity and effectiveness of our proposed method are confirmed through several numerical examples
Tailoring confining jacket for concrete column using ultra high performance-fiber reinforced cementitious composites (UHP-FRCC) with high volume fly ash (HVFA)
Ultra-High Performance Fibre-Reinforced Cementitious Composites (UHP-FRCC) show excellent mechanical performances in terms of strength, ductility, and durability. Therefore, these cementitious materials have been successfully used for repairing, strengthening, and seismic retrofitting of old structures. However, UHP-FRCCs are not always environmental friendly products, especially in terms of the initial cost, due to the large quantity of cement that is contained in the mixture. Different rates of fly ash substitute herein part of the cement, and the new UHP-FRCCs are used to retrofit concrete columns to overcome this problem. To simulate the mechanical response of these columns, cylindrical specimens, which are made of normal concrete and reinforced with different UHP-FRCC jackets, are tested in uniaxial compression. Relationships between the size of the jacket, the percentage of cement replaced by fly ash, and the strength of the columns are measured and analyzed by means of the eco-mechanical approach. As a result, a replacement of approximately 50% of cement with fly ash, and a suitable thickness of the UHP-FRCC jacket, might ensure the lowest environmental impact without compromising the mechanical performances
Mechanism of Anomalous Tunneling in Condensed Bose System
We clarify the origin of anomalous tunneling [Yu. Kagan et al. Phys. Rev.
Lett. 90 (2003) 130402] i.e. the perfect transmission at low energy limit of
tunneling of phonon excitations across the potential barrier separating two
Bose condensates. The perfect transmission is a consequence of the coincidence
of the wave function of the excited state at low energy limit and the
macroscopic wave function of the condensate. We show that the perfect
transmission at low energy occurs even at finite temperatures within the scheme
of Popov approximation.Comment: 4 pages 1 figur
Evaluation of a computational model to predict elbow range of motion
© 2014 The Author(s). Computer models capable of predicting elbow flexion and extension range of motion (ROM) limits would be useful for assisting surgeons in improving the outcomes of surgical treatment of patients with elbow contractures. A simple and robust computer-based model was developed that predicts elbow joint ROM using bone geometries calculated from computed tomography image data. The model assumes a hinge-like flexion-extension axis, and that elbow passive ROM limits can be based on terminal bony impingement. The model was validated against experimental results with a cadaveric specimen, and was able to predict the flexion and extension limits of the intact joint to 0° and 3°, respectively. The model was also able to predict the flexion and extension limits to 1° and 2°, respectively, when simulated osteophytes were inserted into the joint. Future studies based on this approach will be used for the prediction of elbow flexion-extension ROM in patients with primary osteoarthritis to help identify motion-limiting hypertrophic osteophytes, and will eventually permit real-time computer-assisted navigated excisions
Association of blood pressure and renal outcome in patients with chronic kidney disease; a post hoc analysis of FROM-J study
It is well-known that hypertension exacerbates chronic kidney disease (CKD) progression, however, the optimal target blood pressure (BP) level in patients with CKD remains unclear. This study aimed to assess the optimal BP level for preventing CKD progression. The risk of renal outcome among different BP categories at baseline as well as 1 year after, were evaluated using individual CKD patient data aged between 40 and 74 years from FROM-J [Frontier of Renal Outcome Modifications in Japan] study. The renal outcome was defined as >= 40% reduction in estimated glomerular filtration rate to130 mmHg group. A significant increase in the renal outcome was found only in the group of diastolic BP >= 90 mmHg. The group of BP= 130 mmHg at baseline. Targeting SBP level<130 mmHg would be associated with the preferable renal outcome.Clinical Trial Registration-URL: https://www.umin.ac.jp/ctr/. Unique identifier: UMIN000001159 (16/05/2008)
Electronic defect study on low temperature processed Cu(In,Ga)Se2 thin-film solar cells and the influence of an Sb layer
A way to lower the manufacturing cost of Cu(In,Ga)Se-2 (CIGS) thin-film solar cells is to use flexible polymer substrates instead of rigid glass. Because such substrates require lower temperature during absorber deposition, the grain growth of the absorber layer can be hindered which leads to a lower cell performance. Partial compensation of this efficiency loss might be accomplished by growing the absorber in the presence of Sb, which is reported to promote grain growth. In this work CIGS solar cells, deposited on glass substrates, at a reduced substrate temperature with a thin Sb layer (7, 12 nm) on top of the Mo contact are investigated. The diffusion profile of Sb is measured with plasma profiling time of flight mass spectrometry. The beneficial effect of Sb on efficiency and grain size is shown in quantum efficiency measurements and with scanning electron microscopy, respectively. Electric spectroscopy is used to explore the possible effects on the defect structure, more in particular on the dominant shallow acceptor. Admittance spectra exhibit a capacitance step to the geometric capacitance plateau at low temperature (5-60 K). Analyzing this capacitance step, we obtained a good estimate of the activation energy of the intrinsic defects that provide the p-type conductivity of the CIGS absorber. The measurements did not show a change in the nature of the dominant acceptor upon Sb treatment
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