865 research outputs found
On Constructing the Analytical Solutions for Localizations in a Slender Cylinder Composed of an Incompressible Hyperelastic Material
In this paper, we study the localization phenomena in a slender cylinder
composed of an incompressible hyperelastic material subjected to axial tension.
We aim to construct the analytical solutions based on a three-dimensional
setting and use the analytical results to describe the key features observed in
the experiments by others. Using a novel approach of coupled series-asymptotic
expansions, we derive the normal form equation of the original governing
nonlinear partial differential equations. By writing the normal form equation
into a first-order dynamical system and with the help of the phase plane, we
manage to solve two boundary-value problems analytically. The explicit solution
expressions (in terms of integrals) are obtained. By analyzing the solutions,
we find that the width of the localization zone depends on the material
parameters but remains almost unchanged for the same material in the post-peak
region. Also, it is found that when the radius-length ratio is relatively small
there is a snap-back phenomenon. These results are well in agreement with the
experimental observations. Through an energy analysis, we also deduce the
preferred configuration and give a prediction when a snap-through can happen.
Finally, based on the maximum-energy-distortion theory, an analytical criterion
for the onset of material failure is provided.Comment: 27 pages 10 figure
Photocatalytic hydrogen evolution over nickel cobalt bimetallic phosphate anchored graphitic carbon nitrides by regulation of the d-band electronic structure
Non-precious metal co-catalysts with high activity and stability are extremely desirable for economically viable photocatalytic molecular hydrogen (H₂) evolution. Herein, nickel cobalt phosphate (NiCo–Pi) was introduced into graphitic carbon nitride layers (g-C₃N₄) via a sonication-assisted ion intercalation method as a substitute for noble metal co-catalysts. Under visible light irradiation, NiCo–Pi/g-C₃N₄ (Ni/Co molar ratio of 4 : 5) exhibited the highest photocatalytic activity (ca. 10 184 μmol h⁻¹ g⁻¹) and stability for H₂ evolution. Synchrotron radiation X-ray absorption spectroscopy (XAS) indicated that NiCo–Pi is closely bound to g-C₃N₄ via covalent binding, which accelerates electron transport. Moreover, the unoccupied d-orbital in NiCo–Pi causes the surface to strongly adsorb atomic hydrogen (*H). Theoretically, density functional theory (DFT) calculations demonstrated that the d-band center position of NiCo–Pi is relocated upon adjusting the Ni/Co molar ratio, which changes the adsorption energy of NiCo–Pi toward intermediate state *H. This work provides new insights for exploring the role of the bimetallic composition in non-noble co-catalysts for highly efficient H₂ evolution
Photocatalytic hydrogen evolution over nickel cobalt bimetallic phosphate anchored graphitic carbon nitrides by regulation of the d-band electronic structure
Non-precious metal co-catalysts with high activity and stability are extremely desirable for economically viable photocatalytic molecular hydrogen (H₂) evolution. Herein, nickel cobalt phosphate (NiCo–Pi) was introduced into graphitic carbon nitride layers (g-C₃N₄) via a sonication-assisted ion intercalation method as a substitute for noble metal co-catalysts. Under visible light irradiation, NiCo–Pi/g-C₃N₄ (Ni/Co molar ratio of 4 : 5) exhibited the highest photocatalytic activity (ca. 10 184 μmol h⁻¹ g⁻¹) and stability for H₂ evolution. Synchrotron radiation X-ray absorption spectroscopy (XAS) indicated that NiCo–Pi is closely bound to g-C₃N₄ via covalent binding, which accelerates electron transport. Moreover, the unoccupied d-orbital in NiCo–Pi causes the surface to strongly adsorb atomic hydrogen (*H). Theoretically, density functional theory (DFT) calculations demonstrated that the d-band center position of NiCo–Pi is relocated upon adjusting the Ni/Co molar ratio, which changes the adsorption energy of NiCo–Pi toward intermediate state *H. This work provides new insights for exploring the role of the bimetallic composition in non-noble co-catalysts for highly efficient H₂ evolution
Canonical explicit B\"{a}cklund transformations with spectrality for constrained flows of soliton hierarchies
It is shown that explicit B\"{a}cklund transformations (BTs) for the
high-order constrained flows of soliton hierarchy can be constructed via their
Darboux transformations and Lax representation, and these BTs are canonical
transformations including B\"{a}cklund parameter and possess a
spectrality property with respect to and the 'conjugated' variable
for which the pair lies on the spectral curve. As model we
present the canonical explicit BTs with the spectrality for high-order
constrained flows of the Kaup-Newell hierarchy and the KdV hierarchy.Comment: 21 pages, Latex, to be published in "PHYSICA A
Constructing N-soliton solution for the mKdV equation through constrained flows
Based on the factorization of soliton equations into two commuting integrable
x- and t-constrained flows, we derive N-soliton solutions for mKdV equation via
its x- and t-constrained flows. It shows that soliton solution for soliton
equations can be constructed directly from the constrained flows.Comment: 10 pages, Latex, to be published in "J. Phys. A: Math. Gen.
B\"{a}cklund transformations for high-order constrained flows of the AKNS hierarchy: canonicity and spectrality property
New infinite number of one- and two-point B\"{a}cklund transformations (BTs)
with explicit expressions are constructed for the high-order constrained flows
of the AKNS hierarchy. It is shown that these BTs are canonical transformations
including B\"{a}cklund parameter and a spectrality property holds with
respect to and the 'conjugated' variable for which the point
belongs to the spectral curve. Also the formulas of m-times
repeated Darboux transformations for the high-order constrained flows of the
AKNS hierarchy are presented.Comment: 21 pages, Latex, to be published in J. Phys.
Applications of Nanomaterials in Electrochemical Enzyme Biosensors
A biosensor is defined as a kind of analytical device incorporating a biological material, a biologically derived material or a biomimic intimately associated with or integrated within a physicochemical transducer or transducing microsystem. Electrochemical biosensors incorporating enzymes with nanomaterials, which combine the recognition and catalytic properties of enzymes with the electronic properties of various nanomaterials, are new materials with synergistic properties originating from the components of the hybrid composites. Therefore, these systems have excellent prospects for interfacing biological recognition events through electronic signal transduction so as to design a new generation of bioelectronic devices with high sensitivity and stability. In this review, we describe approaches that involve nanomaterials in direct electrochemistry of redox proteins, especially our work on biosensor design immobilizing glucose oxidase (GOD), horseradish peroxidase (HRP), cytochrome P450 (CYP2B6), hemoglobin (Hb), glutamate dehydrogenase (GDH) and lactate dehydrogenase (LDH). The topics of the present review are the different functions of nanomaterials based on modification of electrode materials, as well as applications of electrochemical enzyme biosensors
Search for the decay
We search for radiative decays into a weakly interacting neutral
particle, namely an invisible particle, using the produced through the
process in a data sample of
decays collected by the BESIII detector
at BEPCII. No significant signal is observed. Using a modified frequentist
method, upper limits on the branching fractions are set under different
assumptions of invisible particle masses up to 1.2 . The upper limit corresponding to an invisible particle with zero mass
is 7.0 at the 90\% confidence level
First observations of hadrons
Based on events collected with
the BESIII detector, five hadronic decays are searched for via process
. Three of them, ,
, and are observed for the first
time, with statistical significances of 7.4, , and
9.1, and branching fractions of ,
, and ,
respectively, where the first uncertainties are statistical and the second
systematic. No significant signal is observed for the other two decay modes,
and the corresponding upper limits of the branching fractions are determined to
be and at 90% confidence level.Comment: 17 pages, 16 figure
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