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Fibrous perovskite oxide has been the most promising cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs) due to its efficient mass and charge transfer. Herein, a core–shell fiber-structured YCo0.5Fe0.5O3(YCF)–Gd0.1Ce0.9O1.95(GDC) cathode is synthesized via the modified electrospinning technique. These unique YCF–GDC fibers exhibit a uniform diameter of 300 nm, and the GDC particles are attached to the YCF fiber cores. The electrochemical performance demonstrates a relatively low area-specific resistance of 0.66 Ω·cm2at 550 °C in air, which is much lower than 1.56 Ω·cm2of pure YCF fiber cathode. Moreover, the distribution of relaxation times (DRT) analysis results indicate that the introduction of GDC nanoparticles and the core–shell structure greatly facilitate oxygen-ion conduction and charge transfer processes, and the oxygen incorporation process plays a major role in the total polarization resistance. The NiO–GDC|GDC|fibrous YCF–GDC fuel cell shows a maximum power density of 426.5 mW·cm–2at 550 °C. These results display that the core–shell fiber-structured YCF–GDC composite oxide is a promising candidate of highly active cathode for IT-SOFCs.

High catalytic performances of metal-semiconductor heterostructures have gained significant attention in recent years. However, developing fast and low-cost synthesis of multiphase heterojunction catalysts has long been a challenge. Herein, three phases of Cu-CeO2-SrTiO3-δheterojunction catalyst are successfully synthesized by combining with sol-gel and rapid plasma exsolution method. Using dielectric barrier discharge plasma (DBD), Cu nanoparticles are exsolved and uniformly distributed on the surface of CeO2-SrTiO3-δ. This unique multiphase heterojunction catalyst exhibits superior performance in photothermal reverse water gas shift (RWGS) reactions. The yield of CO from this catalyst is impressive at 11.32 mmol g−1h−1, 9 times greater than pure SrTiO3, and the selectivity for CO is high (99.95%). The enhanced activity is primarily attributed to the synergistic effect resulting from the incorporation of three phases of Cu nanoparticles, CeO2, and SrTiO3-δ, as well as their interfaces. The increase in oxygen vacancy sites in CeO2enhances the adsorption of CO2, whereas the doping and exsolution of Cu help to broaden the light absorption range. A significant role is played by the localized surface plasmon resonance (LSPR) effect of Cu nanoparticles in promoting the catalytic performance of RWGS. This study demonstrates a simple and efficient method for fabricating multiphase heterojunction catalysts, providing new strategies for photothermal CO2reduction.

Surface charge states of heterostructures at the nanoscale are of key importance to describing and understanding the electrostatic interactions between catalysts and chemical molecules interfaces. Although the charge transfer between deposited metal nanoparticles and substrates is well studied, the surface charge state of nanoparticles in situgrown from perovskite oxide substrates has not been reported yet. In this work, we demonstrate the evolution of the work function of exsolved Ru nanoparticles in Sr0.9Y0.08Ti0.95Ru0.05O3(SYTR) using the Kelvin probe force microscopy technique. We find that the work function of Ru is determined by the uncovered size of exsolved nanoparticles. On the basis of density functional theory calculations, the Ru nanoparticles cause the redistribution of surface charge and the variation of work function. Meanwhile, the charge transfer between the exsolved nanoparticles and the titanate substrate inherently modulates the work function of Ru. Moreover, the SYTR electrode exhibits a superior electrochemical catalytic activity for CO2electrolysis in a solid oxide electrolyzer due to the accumulation of surface potential around a single Ru nanoparticle. This work provides insights into the charge transfer between the exsolved nanoparticle and the substrate, which could significantly affect the surface properties in metallic nanostructures.

Perovskite oxides have attracted intensive attention for their good electrochemical performance and stability as electrodes for protonic ceramic fuel cells (PCFCs). However, operating under high temperatures and various atmospheres results in a large polarization resistance and sluggish oxygen reduction reaction (ORR) in cathodes. Here, Zn was successfully doped into Sr3Fe2O7-δ(SFO) Ruddlesden-Popper (RP) perovskite cathode and the Sr3Fe1.5Zn0.5O7-δ(SFZ05) shows a superior ORR activity. The polarization resistance of SFZ05 is 0.072 Ω·cm-2, which is 47% lower than that of the undoped SFO, and the maximum peak power density of the single-cell of NiO-BaZr0.1Ce0.7Y0.2O3-δ(BZCY)|BZCY|SFZ05 reaches 523.56 mW·cm-2at 750℃, increased by 22% than SFO. The improvement is attributed to the formation of oxygen vacancies and the increase of proton conductivity. These results display that SFZ05 is a promising candidate for a highly active and stable cathode for PCFCs.

We revealed the mechanism of tuning in-situ nanoparticles exsolution by adjusting the layer number n in layered perovskite as cathode materials for highly efficient CO2electrolysis.

In this paper, we study the Cauchy problem for the modified Camassa-Holm equation mt+umx+2uxm=0,  m=(1-∂x2)2u,u(x,0)=u0(x)∈Hs(ℝ),    x∈ℝ, t>0,and show that the solution map is not uniformly continuous in Sobolev spaces HS(ℝ) for s>7/2. Compared with the periodic problem, the non-periodic problem is more difficult, e.g., it depends on the conservation law. Our proof is based on the estimates for the actual solutions and the approximate solutions, which consist of a low frequency and a high frequency part.

(PrBa)0.95Mn1.9Ru0.1O5+δ(PBMRu) layered double perovskite is turned into a highly active electrode for symmetrical solid oxide fuel cells (SSOFCs) by introducing Ru/RuO2catalysts through in situgrowth, which demonstrates excellent electrochemical properties as both oxygen and fuel electrodes. The catalytically active Ru nanoparticles exsolve during the reducing step of the preparation process and can be oxidized to nanosized RuO2catalysts when operating as an oxygen electrode. Optimized by substitutional Ru and in situnanosized Ru/RuO2catalysts, the favorable electrical conductivities of 14.89 and 146.81 S cm–1are possessed for PBMRu in 5% H2/N2and air at 750 °C, which are much higher than 7.83 and 90.76 S cm–1of (PrBa)0.95Mn2O5+δ(PBM). With Ru and RuO2nanoparticles on the two sides of the cell, respectively, symmetrical single-cell PBMRu–SSZ|SSZ|PBMRu–SSZ (SSZ = Sc2O3-stabilized ZrO2) exhibits an outstanding output performance of 0.92 W cm–2at 750 °C. All of these findings suggest that in situRu/RuO2nanocatalyst-modified PBMRu would be a promising candidate for an electrode in high-performance SSOFC applications.

Abstract: In this paper, we employ the bifurcation method of dynamical systems and the numerical simulation approach of differential equations to study periodic cusp wave solutions and single-solitons for the b-equationwith b>1. The explicit representations of periodic cusp waves and the implicit expressions of single-solitons are obtained. Further, we show that the limits of both periodic cusp waves and single-solitons are peakons which possess explicit expression u=ce−∣x−ct∣. As corollary, the single-solitons equations of the Camassa–Holm equation and the Degasperis–Procesi equation are given. Our theoretical derivations are identical with the numerical simulations. [Copyright &y& Elsevier]

There is much work in the area of solitons, but there appears very little in the way of compactons. After the approach of Adomian decomposition applied successfully (e.g. [Chaos, Solitons & Fractals 13 (2002) 321; Chaos, Solitons & Fractals 13 (2002) 1053; Appl. Math. Comput. 134 (2003) 487; Chaos, Solitons & Fractals 14 (2002) 1151]), we develop a new method to enlarge the window of compacton research, that is, the bifurcation method of traveling wave systems and numerical simulation of traveling wave equation. As above mentioned, we employ both bifurcation method and numerical simulation to investigate bounded traveling waves in a general compressible hyperelastic rod in this paper. We find some new bounded traveling waves, which are defined on finite core regions. Their planar simulative graphs and implicit expressions imply that they possess the properties of compactons. [Copyright &y& Elsevier]

There exists much good work in the area of usual solitons, but there appears little in the field of compacton solutions. Only a few mathematical tools were employed so far. Recently, Yan [Chaos, Solitons & Fractals 14 (2002) 1151] extended the decomposition method to seek compacton solutions of B(m,n) equation utt=(un)xx+(um)xxxx. In this paper we present a different approach, integral approach, to investigate the compacton solutions of the B(m,n) equation. Not only Yan’s results but also many new compacton solutions of the B(m,n) equation are obtained. Our approach is simple and also suitable for studying compacton solutions of some other equations. [Copyright &y& Elsevier]

The method of the phase plane is emploied to investigate the solitary and periodic traveling waves for a class of nonlinear dispersive partial differential equations. By using the bifurcation theory of dynamical systems to do qualitative analysis, all possible phase portraits in the parametric space for the traveling wave systems are obtained. It can be shown that the existence of a singular straight line in the traveling wave system is the reason why smooth solitary wave solutions converge to solitary cusp wave solution when parameters are varied. The different parameter conditions for the existence of solitary and periodic wave solutions of different kinds are rigorously determined.

In this paper we prove the existence of a non-simultaneous collision T-periodic solution (for any given T) for a class of N-body type problems.

In this paper, we use the theory of generalized Poisson bracket (GPB) to build the Poisson structure of three-dimensional “frozen” systems of Hamiltonian systems with slow time variable, and show that under proper conditions, there exists an adiabatic invariant on every closed simply connected symplectic leaf for the time-dependent Hamiltonian systems. If the HamiltonianH(p,q,τ) on these symplectic leaves are periodic with respect to τ and the frozen systems are in some sense strictly nonisochronous, then there are perpetual adiabatic invariants. To illustrate these results, we discuss the classical Lotka-Volterra equation with slowly periodic time-dependent coefficients modeling the interactions of three species.

Periodic solutions of Hopf type and other dynamical behaviors for a four-order differential equation which occurs in the model of infections disease are investigated. The extended theorem about the conditions for the existence of Hopf bifurcation is proved in higher-order differential equations with several parameters. The Hopf bifurcation value is given through the medium of the corresponding coordinate at the Hopf bifurcation point, and depends on one parameter. The paper reveals that the model of Holt and Picker has periodic solutions, and proves the reliability of the numerical solution which is given by Liu Winmin.

In this paper a mathematical model of AIDS is investigated. The conditions of the existence of equilibria and local stability of equilibria are given. The existences of transcritical bifurcation and Hopf bifurcation are also considered, in particular, the conditions for the existence of Hopf bifurcation can be given in terms of the coefficients of the characteristic equation. The method extends the application of the Hopf bifurcation theorem to higher differential equations which occur in biological models, chemical models, and epidemiological models etc.

A new bathymetry processing software package has been developed to postprocess new GLORI-B swath bathymetry data using preexisting techniques. GLORI-B bathymetry is calculated using an interferometry (phase delay) method using the modified GLORIA towfish which has parallel rows of transducers on both sides. We describe four types of artifacts observed during the first use of this new system during Legs 5 and 6 of the Gloria Expedition which surveyed the fastest spreading segment of the global seafloor spreading system and the broad chain of volcanoes near Easter Island. These artifacts include cross-track bias, along-track bias, a 'dropped edge' effect, and random noise. We describe and illustrate how we minimize these artifacts. We merge the SeaBeam 2000 bathymetry data with the GLORI-B bathymetry data to produce a final bathymetric mosaic which covers about 243,400 km2and shows a different style of diffuse widely spread volcanism not previously observed along hotspot chains. The data are used in several studies describing seamount morphology, elastic thickness of the lithosphere, tectonic and geochemical evolution of the area, and mantle flow from a hotspot to a superfast seafloor spreading center.

A new side-scan processing software package has been developed to postprocess data from the new GLORI-B system and SeaBeam 2000 side-scan data using preexisting techniques. We describe the procedures used to process the side-scan data collected during Legs 5, 6 and 7 of the Gloria Expedition in the spring of 1993. The procedures included minimizing artifacts and merging the two types of side-scan data together. The final mosaic shows recent widespread volcanic flows over large areas of the seafloor, unlike any other volcanic chain surveyed on the seafloor. The side-scan data were also very useful in dredging young rocks which are described in recently submitted geochemical manuscripts. The unique style of widespread low-lying young volcanism is attributed to the combination of superfast seafloor spreading and an underlying hotspot channel.

The effect on a high frequency (RF) voltage distribution to a particle motion stability was analyzed, by means of an asymtotic method of a non-linear mechanics, and the maximal accelerating voltage of a main cavily and maximal voltage gradient of an auxiliary Cavily allowed by dynamics were desived

The purpose of this paper is to investigate the dynamic behaviour of saddle form cable-suspended roofs under vertical excitation action. The governing equations of this problem are system of nonlinear partial differential and integral equations. We first establish a spectral equation, and then consider a model with one coefficient, i.e., a perturbed Duffing equation. The analytical solution is derived for the Duffing equation. Successive approximation solutions can be obtained in likely way for each time to only one new unknown function of time. Numerical results are given for our analytical solution. By using the Melnikov method, it is shown that the spectral system has chaotic solutions and subharmonic solutions under determined parametric conditions.

This paper is concerned with the periodic boundary value problem for a quasilinear evolution equation of the following type: ∂tu+f(u)∂xu+F(u)=0, x∈T=R/2πZ, t∈R+. Under some conditions, we prove that this equation is locally well-posed in Besov space Bp,rs(T). Furthermore, we study the continuity of the solution map for this equation in B2,rs(T). Our work improves some earlier results.