We study a class of non-stationary shot noise processes which have a general arrival process of noises with non-stationary arrival rate and a general shot shape function. Given the arrival times, the shot noises are conditionally independent and each shot noise has a general (multivariate) cumulative distribution function (c.d.f.) depending on its arrival time. We prove a functional weak law of large numbers and a functional central limit theorem for this new class of non-stationary shot noise processes in an asymptotic regime with a high intensity of shot noises, under some mild regularity conditions on the shot shape function and the conditional (multivariate) c.d.f. We discuss the applications to a simple multiplicative model (which includes a class of non-stationary compound processes and applies to insurance risk theory and physics) and the queueing and work-input processes in an associated non-stationary infinite-server queueing system. To prove the weak convergence, we show new maximal inequalities and a new criterion of existence of a stochastic process in the space given its consistent finite dimensional distributions, which involve a finite set function with the superadditive property. 相似文献
We propose a high-quality refractive index sensing by utilizing the characteristic guided-mode resonance (GMR) excited in a simple one-dimensional all-dielectric nano-slit array. We demonstrate a figure of merit up to 12000, which is higher than that achieved in most plasmonic refractive index sensors. We show that high-quality sensing performance can be sustained over a broadband range in near infrared region with relatively large variations in both grating depth and angle of incidence. Such a GMR-based all-dielectric sensing device with the ease of fabrication is expected to hold great promise for realizing broadband refractive index sensors with high performance and compactness. 相似文献
Cascade charge transfer was realized by a H‐bond linked zinc phthalocyanine/BiVO4 nanosheet (ZnPc/BVNS) composite, which subsequently works as an efficient wide‐visible‐light‐driven photocatalyst for converting CO2 into CO and CH4, as shown by product analysis and 13C isotopic measurement. The optimized ZnPc/BVNS nanocomposite exhibits a ca. 16‐fold enhancement in the quantum efficiency compared with the reported BiVO4 nanoparticles at the excitation of 520 nm with an assistance of 660 nm photons. Experimental and theoretical results show the exceptional activities are attributed to the rapid charge separation by a cascade Z‐scheme charge transfer mechanism formed by the dimension‐matched ultrathin (ca. 8 nm) heterojunction nanostructure. The central Zn2+ in ZnPc could accept the excited electrons from the ligand and then provide a catalytic function for CO2 reduction. This Z‐scheme is also feasible for other MPc, such as FePc and CoPc, together with BVNS. 相似文献
A shape-memory double network hydrogel consists of two polymer networks: a chemically crosslinked primary network that is responsible for the permanent shape and a physically crosslinked secondary network that is used to fix the temporary shapes. The formation/melting transition of the secondary network serves as an effective mechanism for the double network hydrogel's shape-memory effect. When the crosslinks in the secondary network are dissociated by applying an external stimulus, only the primary network is left to support the load. When the secondary network is re-formed by removing the stimulus, both the primary and secondary networks support the load. In the past, models have been developed for the constitutive behaviors of double network hydrogels, but the model of shape-memory double network hydrogels is still lacking. This work aims to build a constitutive model for the polyacrylamide-gelatin double network shape-memory hydrogel developed in our previous work. The model is first calibrated by experimental data of the double network shape-memory hydrogel under uniaxial loading and then employed to predict the shape-fixing performance of the hydrogel. The model is also implemented into a three-dimension finite element code and utilized to simulate the shape-memory behavior of the double network hydrogel with inhomogeneous deformations related to applications.
Graphic abstract
A shape-memory double network hydrogel consists of a chemically crosslinked primary network and a physically crosslinked secondary network. The formation/melting transition of the secondary network serves as an effective mechanism for the shape-memory effect of the double network hydrogel. This work built a constitutive model for the polyacrylamide-and-gelatin double network shape-memory hydrogel. The model was first calibrated by experimental data and then employed to predict the shape-fixing performance of the hydrogel. The model was also implemented into a three-dimension finite element code and utilized to simulate the shape-memory behavior of double network hydrogel in complex geometries.
Cellulose - Multifunctional cotton fabrics were fabricated by coating of anionic waterborne polyurethane (WPU)/Cu2-XSe. The surface morphology of WPU/Cu2-XSe coated cotton fabric was characterized... 相似文献