Search Results (11)

Sustainable management of sediment-laden rivers is essential for balancing flood control, ecological protection, and socioeconomic development. The Upper Yellow River, supporting 160 million people, faces escalating challenges in maintaining channel stability under intensified water–sediment imbalances. This study investigates the Sipaikou reach in Ningxia—a representative wandering channel with multiple mid-channel shoals—through integrated UAV-USV-GNSS RTK field measurements and hydrodynamic and sediment transport modeling. Field measurements reveal that mid-channel shoal morphology coupled with bend circulation governs flow division patterns, with discharge ratios of 44.16% and 86.31% at the primary and secondary shoals, respectively. Gaussian kernel density estimation demonstrates velocity distributions evolving from right-skewed to left-skewed around shoals, while spur dike regions display strong left skewness with concentrated main flow. Numerical simulations under six discharge scenarios indicate: (1) Head loss exhibits diminishing marginal effects at the primary shoal, an inflection point at a critical discharge at the secondary shoal, and superlinear growth in the spur dike region. (2) The normal-flow period represents the critical threshold for erosion–deposition regime transition. (3) Spur dike series achieve bank protection through main flow constriction and inter-dike low-velocity zone creation. These findings provide scientific foundations for sustainable flood risk management and ecological restoration in wandering rivers. The integrated measurement–simulation framework offers a transferable methodology for adaptive river management under changing hydrological conditions. Full article

Citation networks are fundamental for analyzing the mechanisms and patterns of knowledge creation and dissemination. While most studies focus on pairwise attachment between papers, they often overlook compound relational structures, such as co-citation. Combining two key empirical features, superlinear node inflow and the temporal decay of node influence, we propose the Triangular Evolutionary Model of Superlinear Growth and Aging (TEM-SGA). The fitting results demonstrate that the TEM-SGA reproduces key structural properties of real citation networks, including degree distributions, generalized degree distributions, and average clustering coefficients. Further structural analyses reveal that the impact of aging varies with structural scale and depends on the interplay between aging and growth, one manifestation of which is that, as growth accelerates, it increasingly offsets aging-related disruptions. This motivates a degenerate model, the Triangular Evolutionary Model of Superlinear Growth (TEM-SG), which excludes aging. A theoretical analysis shows that its degree and generalized degree distributions follow a power law. By modeling interactions among triadic closure, dynamic expansion, and aging, this study offers insights into citation network evolution and strengthens its theoretical foundation. Full article

This paper examines temporal symmetry breaking and structural duality in a class of time-changed McKean–Vlasov neutral stochastic differential equations. The system features super-linear drift coefficients satisfying a one-sided local Lipschitz condition and incorporates a fundamental duality: one drift component evolves under a random time change $E_t$, while the other progresses in regular time t. Within the symmetric framework of mean-field interacting particle systems, where particles exhibit permutation invariance, we establish strong convergence of the tamed Euler–Maruyama method over finite time intervals. By replacing the one-sided local condition with a globally symmetric Lipschitz assumption, we derive an explicit convergence rate for the numerical scheme. Two numerical examples validate the theoretical results. Full article

This paper discusses the existence of positive radial symmetric solutions of the nonlinear biharmonic equation ${▵}^{2}u=f(u,▵u)$ on an annular domain $\Omega$ in ${\mathbb{R}}^N$ with the Navier boundary conditions ${u|}_{\partial \Omega }=0$ and ${▵u|}_{\partial \Omega }=0$, where $f:{\mathbb{R}}^{+}\times {\mathbb{R}}^{-}\to {\mathbb{R}}^{+}$ is a continuous function. We present some some inequality conditions of f to obtain the existence results of positive radial symmetric solutions. These inequality conditions allow $f(\xi ,\eta )$ to have superlinear or sublinear growth on $\xi ,\eta$ as $\left|\right(\xi ,\eta \left)\right|\to 0$ and ∞. Our discussion is mainly based on the fixed-point index theory in cones. Full article

This paper concerns with the existence of radial solutions of the biharmonic elliptic equation ${▵}^{2}u=f\left(\right|x|,u,|\nabla u|,▵u)$ in an annular domain $\Omega =\{x\in {\mathbb{R}}^N:r_1<|x|<r_2\}$($N\ge 2$) with the boundary conditions ${u|}_{\partial \Omega }=0$ and ${▵u|}_{\partial \Omega }=0$, where $f:[r_1,r_2]\times \mathbb{R}\times {\mathbb{R}}^{+}\times \mathbb{R}\to \mathbb{R}$ is continuous. Under certain inequality conditions on f involving the principal eigenvalue ${\lambda }_1$ of the Laplace operator $-▵$ with boundary condition ${u|}_{\partial \Omega }=0$, an existence result and a uniqueness result are obtained. The inequality conditions allow for $f(r,\xi ,\zeta ,\eta )$ to be a superlinear growth on $\xi ,\zeta ,\eta$ as $\left|\right(\xi ,\zeta ,\eta \left)\right|\to \infty$. Our discussion is based on the Leray–Schauder fixed point theorem, spectral theory of linear operators and technique of prior estimates. Full article

In the diffusion approximation of the neutral Wright–Fisher model, the expected time until fixation or loss of a neutral allele is proportional to the initial entropy of the distribution of the allele in the population. No explanation is known for this coincidence. In this paper, we show that the rate of entropy dissipation is proportional to the number of segregating alleles. Since the final fixed state has zero entropy, the expected lifetime of segregating alleles is proportional to the initial entropy in the system. We show that classical formulae on the average time to loss of segregating alleles and the expected time to fixation of the last segregating allele stem from these properties of the diffusion process. We also extend our results to the case of population size changing in time. The dissipation of heterozygosity and entropy shows that superlinear population growth leads to infinite expected fixation times, i.e., neutral alleles in fast-growing populations could segregate forever without ever becoming fixed or disappearing by genetic drift. Full article

We propose a novel graded AlGaAsSb layer growth method to achieve a super-linear interface by precisely controlling the cell temperature and valve position. Atomically smooth surface and lattice-matched epitaxy was confirmed by AFM and the HRXRD characterization of the graded AlGaAsSb layer sample. With the inserted graded layer between the cladding and waveguide layers, high-power, high-efficiency GaSb-based laser emitters and laser bars were confirmed. The linearly graded interface layer smooths the potential barrier peak between the cladding and waveguide layers, which resulted in a low turn-on voltage of 0.65 V and an ultra-low series resistance of 0.144 Ω. A maximum continuous-wave output power of 1.8 W was obtained with a high power conversion efficiency of 28% at 1.1 A and 12% at 8 A. A facet-coated laser bar was also fabricated with a record-high CW output power of 18 W. A high internal quantum efficiency of 83 was maintained at 40 °C, implying improved carrier injection efficiency, which benefits from the built-in electric field of the composition-graded AlGaAsSb layer. Full article

We prove the existence of radially symmetric solutions and the validity of Euler–Lagrange necessary conditions for a class of variational problems with slow growth. The results are obtained through the construction of suitable superlinear perturbations of the functional having the same minimizers of the original one. Full article

Urbanization drives the need for predictive and quantitative methods to understand city growth and adopt informed urban planning. Population increases trigger changes in city attributes that are explicable by scaling laws. These laws show superlinear scaling of communication with population size, asserting an increase in human interaction based on city size. However, it is not yet known if this is the case for social interaction among close contacts, that is, whether population growth influences connectivity in a close circle of social contacts that are dynamic and short-spanned. Following this, a network is configured, named contact networks, based on familiarity. We study the urban scaling property for three social connectivity parameters (degree, call frequency, and call volume) and analyze it at the collective level and the individual level for various cities around the world. The results show superlinear scaling of social interactions based on population for contact networks; however, the increase in level of connectivity is minimal relative to the general scenario. The statistical distributions analyze the impact of city size on close individual interactions. As a result, knowledge of the quantitative increase in social interaction with urbanization can help city planners in devising city plans, developing sustainable economic policies, and improving individuals’ social and personal lives. Full article

We study one-dimensional p-Laplacian problems and answer the unsolved problem. Our method is to study the property of the operator, the concavity of the solutions and the continuity of the first eigenvalues. By the above study, the main difficulty is overcome and the fixed point theorem can be applied for the corresponding compact maps. An affirmative answer is given to the unsolved problem with superlinearity. A global growth condition is not imposed on the nonlinear term f. The assumptions of this paper are more general than the usual, thus the existing results cannot be utilized. Some recent results are improved from weak solutions to classical solutions and from $p\ge 2$ to $p\in (1,\infty ).$ Full article

This work deals with the use of hydrotalcite nanoparticle post-diffusion in layer by layer (LbL) coatings with the aim of improving their flame retardant action on cotton. The selected LbL components, which encompass polydiallyldimethylammonium chloride and deoxyribonucleic acid, aim at the deposition of an intumescent coating. Infrared spectra pointed out a super-linear growth of the investigated assembly, indicating the ability to deposit thick coatings while maintaining a relatively low deposition number. A post-diffusion process, performed by exposing the LbL-treated fabrics to two different concentrations of hydrotalcite water suspensions (0.1 or 1 wt %), was carried out to improve the fireproofing efficiency of these coatings. Coatings treated with the lowest concentration suspension partially swelled as a consequence of their structural rearrangements while the use of the highest concentration led to nanoparticle aggregates. Horizontal flame spread tests were used for assessing the achieved flame retardant properties. The post-diffusion performed at the lowest hydrotalcite concentration lowers the minimum number of Bi-Layers required for obtaining cotton self-extinguishment while samples treated with the highest concentration showed detrimental effects on the performances of treated fabrics. This behavior is ascribed to the effects of hydrotalcite particles on the intumescence of LbL coatings, as evidenced by the morphological analyses of post-combustion residues. Full article