The NH 2 -graphene/polyaniline composites are synthesized by in situ electropolymerization of aniline monomer and NH 2 -functionalized graphene (“NH 2 -graphene”) sheets in acidic electrolyte solution by constant-po...
The NH 2 -graphene/polyaniline composites are synthesized by in situ electropolymerization of aniline monomer and NH 2 -functionalized graphene (“NH 2 -graphene”) sheets in acidic electrolyte solution by constant-potential coulometry. Cyclic voltammetry and FTIR analyses confirm the covalent attachment of polyaniline backbone onto NH 2 -graphene in the composite. Having the same functional moieties (NH 2 -group), the polyaniline nanofibers are grafted laterally forming ’synapses’ resulting in improved charge-transfer reaction and stability of the composite. This link is believed to be ’phenazine-like’ microstructure formed at the edges of graphene sheets as evidenced by SEM and TEM images. The voltammograms of the NH 2 -graphene/polyaniline composite films coated onto pencil lead graphite electrodes (PLGE) exhibit remarkable increase in the current density relative to the bare PLGE and polyaniline-coated PLGEs. Based on the electrochemical impedance spectroscopy (EIS) measurements, the enhancement in the electrochemical properties of the composite may be due to the good chargetransfer redox activity of polyaniline fibers that are grafted onto the NH 2 -graphene sheet. The composite film also demonstrated photo-responsive property which could be useful for sensing or photovoltaic cell design.
Daily, vast amounts of waste are produced in the orange juice industry, a large part of which is reused in low-added-value products. In this work, orange vesicle fiber residues from the juice sieving stage were plasti...
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Daily, vast amounts of waste are produced in the orange juice industry, a large part of which is reused in low-added-value products. In this work, orange vesicle fiber residues from the juice sieving stage were plasticized by extrusion, producing a thermoplastic citrus pulp (TCP). This pulp was incorporated into poly(butylene succinate) (PBS) at up to 50 wt %. The influence of TCP on the molar mass, morphology, tensile properties, rheological behavior, and biodeterioration of PBS in soil was evaluated. Highly flexible compounds with elongations similar to those of PBS were produced. Scanning electron microscopy analyses suggested good dispersion between the TCP and PBS phases, verified after acid extraction of pectin. Rheological analyses indicated the presence of strong interactions in the interconnected network formed by pectin gel, percolation of TCP lignocellulosic fibers, or both. Analyses of mass loss by burial in soil showed that the higher the TCP content in PBS is, the higher and faster the biodeterioration is. Size exclusion chromatography analyses indicated that the greater the concentration of TCP and the better dispersed it was in the compounds, the lower molar masses populations appeared in PBS, indicating higher rates of degradation of PBS in the presence of TCP. This innovative approach not only reuses the waste produced in the orange juice industry but also demonstrates the potential for obtaining environmentally friendly compounds.
The superposition of atomic vibrations and flexoelectronic effect gives rise to a cross correlation between free charge carriers and temporal magnetic moment of phonons in conducting heterostructures under an applied ...
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The superposition of atomic vibrations and flexoelectronic effect gives rise to a cross correlation between free charge carriers and temporal magnetic moment of phonons in conducting heterostructures under an applied strain gradient. The resulting dynamical coupling is expected to give rise to quasiparticle excitations called magnetoelectronic electromagnons that carry electronic charge and temporal magnetic moment. Here, we report experimental evidence of magnetoelectronic electromagnons in the freestanding degenerately doped p-Si based heterostructure thin film samples. These quasiparticle excitations give rise to long-distance (>100 μm) spin transport, demonstrated using spatially modulated transverse magnetothermoelectric and nonlocal resistance measurements. The magnetoelectronic electromagnons are nonreciprocal and give rise to large magnetochiral anisotropy (0.352A−1T−1) that diminishes at lower temperatures. The superposition of nonreciprocal magnetoelectronic electromagnons gives rise to longitudinal and transverse modulations in charge carrier density, spin density, and magnetic moment, demonstrated using the Hall effect and edge dependent magnetoresistance measurements, which can also be called inhomogeneous magnetoelectronic multiferroic effect. These quasiparticle excitations are analogous to photons where time dependent polarization and temporal magnetic moment replace electric and magnetic field, respectively, and most likely topological because they manifest topological Nernst effect. Hence, the magnetoelectronic electromagnon can potentially give rise to quantum interference and entanglement effects in conducting solid state systems at room temperature in addition to efficient spin transport.
Electrochemical glycerol oxidation(EGO)emerges as a promising route to valorize glycerol,an underutilized byproduct from biodiesel production,into value-added *** study employed three types of gold(Au)nanocrystals wit...
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Electrochemical glycerol oxidation(EGO)emerges as a promising route to valorize glycerol,an underutilized byproduct from biodiesel production,into value-added *** study employed three types of gold(Au)nanocrystals with controlled shapes to elucidate the facet-dependent electrocatalytic behavior in ***,rhombic dodecahedral,and cubic Au nanocrystals with{111},{110},and{100}facets,respectively,were precisely synthesized with uniform size and *** dodecahedra exhibited the lowest onset potential for EGO due to facile AuOH formation,while octahedra showed enhanced electrochemical activity for glycerol oxidation and resistance to ***-situ FTIR analysis revealed that Au{111}surfaces selectively favored C_(2) products,whereas Au{100}surfaces promoted C_(3) product formation,highlighting the significant effect of facet orientation on EGO performance and informing catalyst design.
Laser direct writing employing multi-photon 3D polymerisation is a scientific and industrial tool used in various fields such as micro-optics,medicine,metamaterials,programmable materials,etc.,due to the fusion of hig...
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Laser direct writing employing multi-photon 3D polymerisation is a scientific and industrial tool used in various fields such as micro-optics,medicine,metamaterials,programmable materials,etc.,due to the fusion of highthroughput and fine features down to hundreds of *** limitations of technology applicability emerge from photo-resin properties,however any material modifications can strongly affect its printability,as photoexcitation conditions alter as *** we present wavelength-independent 3D polymerisation using low peak power laser *** pulse repetition rate and fast laser direct writing was employed for advancing additive manufacturing out of the SZ2080^(TM)photo-resist without any *** of 517 nm,780 nm,and 1035 nm are shown to be suitable for producing 300 nm polymerized features even at high-up to 10^(5)μm/s-writing *** of organic-inorganic ratio in hybrid material results in shift and decrease of the dynamic fabrication window,yet not prohibiting the *** energy deposition per focal volume is achieved due to localized heating enabling efficient 3D *** spatio-selective photo-chemical crosslinking widens optical manufacturing capacity of non-photo-sensitive materials.
The slow kinetics at the cathode of oxygen reduction reaction(ORR)seriously limits the efficiencies of fuel cells and metal-air ***,the state-of-the-art ORR electrocatalyst,suffers from high cost,low earth abundance,a...
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The slow kinetics at the cathode of oxygen reduction reaction(ORR)seriously limits the efficiencies of fuel cells and metal-air ***,the state-of-the-art ORR electrocatalyst,suffers from high cost,low earth abundance,and poor *** a self-templated strategy based on metal-organic frameworks(MOFs)is proposed for the fabrication of hollow nitrogen-doped carbon spheres that are embedded with cobalt nanoparticles(Co/HNC).The Co/HNC manifests better ORR activities,methanol tolerance,and stability than commercial Pt/*** high ORR performance of Co/NHC can be attributed to the hollow structure which provides enlarged electrochemically active surface area,the formation of more Co-N species,and the introduction of *** work highlights the significance of rational engineering of MOFs for enhanced ORR activity and stability and offers new routes to the design and synthesis of high-performance electrocatalysts.
A physics-constrained deep learning surrogate that predicts the exponential "avalanche" growth rate of runaway electrons (REs) for a plasma containing partially ionized impurities is developed. Specifically,...
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We design microresonators for octave-spanning soliton frequency comb generation in silicon nitride. We lock the repetition rate via an electro-optic comb and achieve phase noise of -130-dBc/Hz, with the resultant modu...
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作者:
Yu QiaoProgram of Materials Science and Engineering
University of California–San Diego La Jolla California 92093 USA and Department of Structural Engineering University of California–San Diego La Jolla California 92093-0085 USA
Recent research on the fundamentals of statistical mechanics has led to an interesting discovery. With locally nonchaotic barriers, as Boltzmann's H theorem is inapplicable, there exist nontrivial nonthermodynamic...
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Recent research on the fundamentals of statistical mechanics has led to an interesting discovery. With locally nonchaotic barriers, as Boltzmann's H theorem is inapplicable, there exist nontrivial nonthermodynamic systems that can produce useful work by absorbing heat from a single thermal reservoir without any other effect, thereby breaking the boundaries of the second law of thermodynamics. The previous analyses used classical mechanical models. In the current investigation, the study is extended to quantum mechanics. First, we reiterate that the Fermi-Dirac distribution and the Bose-Einstein distribution are compatible with the generalized Maxwell's relations, which demonstrates the general robustness of the framework of quantum statistical mechanics. Next, we analyze a set of simple-step scattering problems. When the system is in contact with a thermal reservoir, a bound state inherently follows the second law of thermodynamics, while a scattering state may not. The root cause is associated with the nonlocal nature of the wave function. It implies that the nonthermodynamic phenomena favor unquantized energy and localized wave packets, exhibiting a tendency to occur in “semiclassical” setups.
We design microresonators for octave-spanning soliton frequency comb generation in silicon nitride. We lock the repetition rate via an electro-optic comb and achieve phase noise of -130-dBc/Hz, with the resultant modu...
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