36,972 research outputs found
Enhancement of plasticity in Ti-based metallic glass matrix composites by controlling characteristic and volume fraction of primary phase
In this study, Ti-based metallic glass matrix composites with high plasticity have been developed by controlling characteristic and volume fraction of primary phase embedded in the glass matrix. By careful alloy design procedure, the compositions of ß/glass phases, which are in metastable equilibrium have been properly selected, therefore the mechanical properties can be tailored by selecting the alloy compositions between the composition of ß and glass phases. The relation between the compressive yield strength and volume fraction of ß phase is well described using the rule of mixtures
Fast Fits for Lattice QCD Correlators
We illustrate a technique for fitting lattice QCD correlators to sums of
exponentials that is significantly faster than traditional fitting methods ---
10--40 times faster for the realistic examples we present. Our examples are
drawn from a recent analysis of the Upsilon spectrum, and another recent
analysis of the D -> pi semileptonic form factor. For single correlators, we
show how to simplify traditional effective-mass analyses.Comment: 5 pages, 4 figure
The initial temporal evolution of a feedback dynamo for Mercury
Various possibilities are currently under discussion to explain the observed
weakness of the intrinsic magnetic field of planet Mercury. One of the possible
dynamo scenarios is a dynamo with feedback from the magnetosphere. Due to its
weak magnetic field Mercury exhibits a small magnetosphere whose subsolar
magnetopause distance is only about 1.7 Hermean radii. We consider the magnetic
field due to magnetopause currents in the dynamo region. Since the external
field of magnetospheric origin is antiparallel to the dipole component of the
dynamo field, a negative feedback results. For an alpha-omega-dynamo two
stationary solutions of such a feedback dynamo emerge, one with a weak and the
other with a strong magnetic field. The question, however, is how these
solutions can be realized. To address this problem, we discuss various
scenarios for a simple dynamo model and the conditions under which a steady
weak magnetic field can be reached. We find that the feedback mechanism
quenches the overall field to a low value of about 100 to 150 nT if the dynamo
is not driven too strongly
Overexpression of Both Human Sodium Iodide Symporter (NIS) and BRG1-Bromodomain Synergistically Enhances Radioiodine Sensitivity by Stabilizing p53 through NPM1 Expression.
Improved therapeutic strategies are required to minimize side effects associated with radioiodine gene therapy to avoid unnecessary damage to normal cells and radiation-induced secondary malignancies. We previously reported that codon-optimized sodium iodide symporter (oNIS) enhances absorption of I-131 and that the brahma-associated gene 1 bromodomain (BRG1-BRD) causes inefficient DNA damage repair after high-energy X-ray therapy. To increase the therapeutic effect without applying excessive radiation, we considered the combination of oNIS and BRG1-BRD as gene therapy for the most effective radioiodine treatment. The antitumor effect of I-131 with oNIS or oNIS+BRD expression was examined by tumor xenograft models along with functional assays at the cellular level. The synergistic effect of both BRG1-BRD and oNIS gene overexpression resulted in more DNA double-strand breaks and led to reduced cell proliferation/survival rates after I-131 treatment, which was mediated by the p53/p21 pathway. We found increased p53, p21, and nucleophosmin 1 (NPM1) in oNIS- and BRD-expressing cells following I-131 treatment, even though the remaining levels of citrulline and protein arginine deiminase 4 (PAD4) were unchanged at the protein level
A Prediction of the B*_c mass in full lattice QCD
By using the Highly Improved Staggered Quark formalism to handle charm,
strange and light valence quarks in full lattice QCD, and NRQCD to handle
bottom valence quarks we are able to determine accurately ratios of the B meson
vector-pseudoscalar mass splittings, in particular,
(m(B*_c)-m(B_c))/(m(B*_s)-m(B_s)). We find this ratio to be 1.15(15), showing
the `light' quark mass dependence of this splitting to be very small. Hence we
predict m(B_c*) = 6.330(7)(2)(6) GeV where the first two errors are from the
lattice calculation and the third from existing experiment. This is the most
accurate prediction of a gold-plated hadron mass from lattice QCD to date.Comment: 4 pages, 2 figure
Variation of Sound Velocity in Fatigued Aluminum 2024-T4 as a Function fo Hydrostatic Pressure
It is well known that a pressure or stress derivative measurement of the sound velocity gives information about the nonlinear elastic properties of the material under investigation. Over the last several decades numerous experiments on various solids using uniaxial stress apparatus or oil-filled hydrostatic pressure chambers have been reported. In most cases the pressure or stress must be increased to several thousand kilobars to obtain reasonable measurements. The necessity of using such high pressure usually results from the low sensitivity of the devices or techniques used to measure the change in the sound velocity
3D Arbitrary Channel Fabrication for Lab on a Chip Applications using Chemical Decomposition
This article demonstrate a simple method to use of three-dimensionally (3D) printed molds that are chemically decomposable for rapid fabrication of complex and arbitrary microchannel geometries. These complex microchannel are unachievable through existing soft lithography techniques. The molds are printed directly from hand held 3D printing pen that can print in midair, making rapid prototyping of microfluidic devices possible in hours. PLA based copper filament is used to print the arbitrary channels. The printed channels are then placed inside PDMS and PDMS is cured. The cured sample is then immersed in chemical solution (Acetic Acid + Sodium Chloride+ Hydrogen peroxide), which decomposes the PLA based copper channel thus leaving an empty channel inside the PDMS block. This method enable precise control of various device geometries, such as the profile of the channel cross-section and variable channel diameters in a single device
Strange Particles from NEXUS 3
After discussing conceptual problems with the conventional string model, we
present a new approach, based on a theoretically consistent multiple scattering
formalism. First results for strange particle production in proton-proton
scattering at 158 GeV and at 200 GeV (cms) are discussed.Comment: invited talk, given at the Strange Quark Matter Conference, Atlantic
Beach, North Carolina, March 12-17, 200
Planar microwave devices fabricated by ion-implantation patterning of high-temperature superconductors
We have applied ion-implantation inhibit patterning as a new method of fabricating low-loss microwave transmission lines in high-temperature superconductor thin films. To determine the effectiveness of this technique, we fabricated coplanar waveguide transmission lines in YBa2Cu3O7 – thin films that had been deposited on LaAlO3 substrates using pulsed laser deposition. Microwave characterizations of these lines are compared to a reference line fabricated with conventional ion milling. At 76 K and 12 GHz, the attenuation constants of the ion-implanted transmission lines are approximated 0.02 dB/mm, and the overall loss response is indistinguishable from that of the ion-milled device.published_or_final_versio
Five-dimensional AGT Conjecture and the Deformed Virasoro Algebra
We study an analog of the AGT relation in five dimensions. We conjecture that
the instanton partition function of 5D N=1 pure SU(2) gauge theory coincides
with the inner product of the Gaiotto-like state in the deformed Virasoro
algebra. In four dimensional case, a relation between the Gaiotto construction
and the theory of Braverman and Etingof is also discussed.Comment: 12 pages, reference added, minor corrections (typos, notation
changes, etc
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