250 research outputs found
Combining nano-silicon with oxide glass in anodes for Li-ion batteries
Vanadium-tellurite glasses (VT) have emerged as promising anode materials for lithium-ion batteries (LIBs). Despite this, the Li-ion storage capacity of the VT glass anode is still insufficient to meet the demands for the next generation of advanced LIBs. Silicon (Si) anode has ultrahigh theoretical capacity but suffers from significant volume expansion during lithiation and delithiation. In this work, we combined Si nanoparticles with VT glass to prepare Si@VT composite anode for LIBs. The composite was produced through heat-treatment at different temperatures, some of which were hot-pressed under the isostatic pressure of 100 MPa. The Si@VT composite exhibited a synergistic effect that integrated the strengths of both VT glass and Si, resulting in a substantial enhancement of its electrochemical performance. The systematic characterizations of the composite-based anodes revealed the optimal conditions for fabricating the high-performance Si@VT composite: a silicon fraction of 10 wt% and a hot-pressing temperature of 620 K. This composite stood out as the optimal choice, exhibiting a capacity of 353 mA h g−1 at 1 A g−1 after 1000 cycles. This capacity surpasses that of VT glass anode by over threefold and that of pure Si anode by twelvefold.</p
Fabrication and Properties of Composites of Poly(ethylene oxide) and Functionalized Carbon Nanotubes
Carbon nanotubes (CNTs) [1, 2] have dimensions similar to those of typical polymeric
chains, with 1-50nm in diameter and 1-10μm in length. Experimental results on individual carbon
nanotubes and nanotube bundles show that they have exceptional electrical and mechanical
properties with an elastic modulus of ~1TPa and fracture strain of 5-10%. [3] The thermal
conductivity of the nanotubes is expected to be higher than that of the carbon fibers because of their
structural perfection. As a result there are considerable interests in utilization of CNTs as fillers for
thermal management and structural reinforcement. Although there have been several published
studies on polymer-CNT composites [4-9], realization of the expected enhancement in properties,
especially mechanical properties, has by and large not been demonstrated. This is in part because of
the difficulties in materials processing arising from insolubility of the pristine CNTs
Exact diagonalization of the generalized supersymmetric t-J model with boundaries
We study the generalized supersymmetric model with boundaries in three
different gradings: FFB, BFF and FBF. Starting from the trigonometric R-matrix,
and in the framework of the graded quantum inverse scattering method (QISM), we
solve the eigenvalue problems for the supersymmetric model. A detailed
calculations are presented to obtain the eigenvalues and Bethe ansatz equations
of the supersymmetric model with boundaries in three different
backgrounds.Comment: Latex file, 32 page
AvrRpm1 Functions as an ADP-Ribosyl Transferase to Modify NOI Domain-Containing Proteins, Including Arabidopsis and Soybean RPM1-Interacting Protein4
The Pseudomonas syringae effector protein AvrRpm1 activates the Arabidopsis (Arabidopsis thaliana) intracellular innate immune receptor protein RESISTANCE TO PSEUDOMONAS MACULICOLA1 (RPM1) via modification of a second Arabidopsis protein, RPM1-INTERACTING PROTEIN4 (AtRIN4). Prior work has shown that AvrRpm1 induces phosphorylation of AtRIN4, but homology modeling indicated that AvrRpm1 may be an ADP-ribosyl transferase. Here, we show that AvrRpm1 induces ADP-ribosylation of RIN4 proteins from both Arabidopsis and soybean (Glycine max) within two highly conserved nitrate-induced (NOI) domains. It also ADP ribosylates at least 10 additional Arabidopsis NOI domain-containing proteins. The ADP-ribosylation activity of AvrRpm1 is required for subsequent phosphorylation on Thr-166 of AtRIN4, an event that is necessary and sufficient for RPM1 activation. We also show that the C-terminal NOI domain of AtRIN4 interacts with the exocyst subunits EXO70B1, EXO70E1, EXO70E2, and EXO70F1. Mutation of either EXO70B1 or EXO70E2 inhibited secretion of callose induced by the bacterial flagellin-derived peptide flg22. Substitution of RIN4 Thr-166 with Asp enhanced the association of AtRIN4 with EXO70E2, which we posit inhibits its callose deposition function. Collectively, these data indicate that AvrRpm1 ADP-ribosyl transferase activity contributes to virulence by promoting phosphorylation of RIN4 Thr-166, which inhibits the secretion of defense compounds by promoting the inhibitory association of RIN4 with EXO70 proteins
Low-Cycle Fatigue of Ultra-Fine-Grained Cryomilled 5083 Aluminum Alloy
The cyclic deformation behavior of cryomilled (CM) AA5083 alloys was compared to that of conventional AA5083-H131. The materials studied were a 100 pct CM alloy with a Gaussian grain size average of 315 nm and an alloy created by mixing 85 pct CM powder with 15 pct unmilled powder before consolidation to fabricate a plate with a bimodal grain size distribution with peak averages at 240 nm and 1.8 μm. Although the ultra-fine-grain (UFG) alloys exhibited considerably higher tensile strengths than those of the conventional material, the results from plastic-strain-controlled low-cycle fatigue tests demonstrate that all three materials exhibit identical fatigue lives across a range of plastic strain amplitudes. The CM materials exhibited softening during the first cycle, similar to other alloys produced by conventional powder metallurgy, followed by continual hardening to saturation before failure. The results reported in this study show that fatigue deformation in the CM material is accompanied by slight grain growth, pinning of dislocations at the grain boundaries, and grain rotation to produce macroscopic slip bands that localize strain, creating a single dominant fatigue crack. In contrast, the conventional alloy exhibits a cell structure and more diffuse fatigue damage accumulation
Partial Wave Analysis of
BES data on are presented. The
contribution peaks strongly near threshold. It is fitted with a
broad resonance with mass MeV, width MeV. A broad resonance peaking at 2020 MeV is also required
with width MeV. There is further evidence for a component
peaking at 2.55 GeV. The non- contribution is close to phase
space; it peaks at 2.6 GeV and is very different from .Comment: 15 pages, 6 figures, 1 table, Submitted to PL
Longitudinal double-spin asymmetry and cross section for inclusive neutral pion production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV
We report a measurement of the longitudinal double-spin asymmetry A_LL and
the differential cross section for inclusive Pi0 production at midrapidity in
polarized proton collisions at sqrt(s) = 200 GeV. The cross section was
measured over a transverse momentum range of 1 < p_T < 17 GeV/c and found to be
in good agreement with a next-to-leading order perturbative QCD calculation.
The longitudinal double-spin asymmetry was measured in the range of 3.7 < p_T <
11 GeV/c and excludes a maximal positive gluon polarization in the proton. The
mean transverse momentum fraction of Pi0's in their parent jets was found to be
around 0.7 for electromagnetically triggered events.Comment: 6 pages, 3 figures, submitted to Phys. Rev. D (RC
Roles of IP3R and RyR Ca2+ Channels in Endoplasmic Reticulum Stress and β-Cell Death
OBJECTIVE—Endoplasmic reticulum (ER) stress has been implicated in the pathogenesis of diabetes, but the roles of specific ER Ca2+ release channels in the ER stress–associated apoptosis pathway remain unknown. Here, we examined the effects of stimulating or inhibiting the ER-resident inositol trisphosphate receptors (IP3Rs) and the ryanodine receptors (RyRs) on the induction of β-cell ER stress and apoptosis
Partonic State and Single Transverse Spin Asymmetries in Semi Inclusive DIS
Using partonic states we verify the transverse momentum dependent
factorization for single transverse spin asymmetries in semi inclusive DIS at
leading but nontrivial order of alpha_s. The factorization has been previously
derived in a formal way by using diagram expansion at hadron level. We find
with our partonic results that two relevant structure functions satisfy the
factorization. Our results also satisfy the collinear factorization but with
the perturbative coefficient different than that derived formally.Comment: Add references and more discussion. Version to appear in Phys. Lett.
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