High-throughput computational material screening of the cycloalkane-based two-dimensional Dion–Jacobson halide perovskites for optoelectronics

Two-dimensional (2D) layered perovskites have emerged as potential alternates to traditional 3D analogs to solve the stability issue of perovskite solar cells. In recent years, many efforts have been spent on manipulating the interlayer organic spacing cation to improve the photovoltaic properties of Dion–Jacobson (DJ) perovskites. In this work, a serious of cycloalkane (CA) molecules were selected as the organic spacing cation in 2D DJ perovskites, which can widely manipulate the optoelectronic properties of DJ perovskites. The underlying relationship between the CA interlayer molecules and the crystal structures, thermodynamic stabilities, and electronic properties of 58 DJ perovskites has been investigated by using automatic high-throughput workflow cooperated with density-functional (DFT) calculations. We have found that these CA-based DJ perovskites are all thermodynamic stable. The sizes of the cycloalkane molecules can influence the degree of inorganic framework distortion and further tune the bandgaps with a wide range of 0.9~2.1 eV. These findings indicate the cycloalkane molecules are suitable for spacing cation in 2D DJ perovskites and provide a useful guidance in designing novel 2D DJ perovskites for optoelectronic applications.

General finite-volume framework for saddle-point problems of various physics

This article is dedicated to the general finite-volume framework used to discretize and solve saddle-point problems of various physics. The framework applies the Ostrogradsky–Gauss theorem to transform a divergent part of the partial differential equation into a surface integral, approximated by the summation of vector fluxes over interfaces. The interface vector fluxes are reconstructed using the harmonic averaging point concept resulting in the unique vector flux even in a heterogeneous anisotropic medium. The vector flux is modified with the consideration of eigenvalues in matrix coefficients at vector unknowns to address both the hyperbolic and saddle-point problems, causing nonphysical oscillations and an inf-sup stability issue. We apply the framework to several problems of various physics, namely incompressible elasticity problem, incompressible Navier–Stokes, Brinkman–Hazen–Dupuit–Darcy, Biot, and Maxwell equations and explain several nuances of the application. Finally, we test the framework on simple analytical solutions.

Stability for the Calderón’s problem for a class of anisotropic conductivities via an ad-hoc misfit functional

We address the stability issue in Calderón’s problem for a special class of anisotropic conductivities of the form σ=γA in a Lipschitz domain Ω⊆R<n>, n≧3, when A is a known Lipschitz continuous matrix-valued function and γ is the unknown piecewise affine scalar function on a given partition of Ω. We define an ad-hoc misfit functional encoding our data and establish estimates for this class of anisotropic conductivities in terms of both the misfit functional and the more commonly used local Dirichlet-to-Neumann map.

Viability of Nanostructured Lipid Carrier System in Overcoming the Barriers Associated with Chemotherapeutic Delivery

Background: Delivery of anti-cancer agents is challenging due to some inherent problems associated with instability, low solubility, non-specificity, variable pharmacokinetics, narrow therapeutic window, multi-drug resistance development, and other physiological barrier related to tumor cells. In recent years, Nanostructured lipid carrier (NLC) has gained considerable importance in improving anti-cancer agents' therapeutic efficacy. Objective: The present review furnishes a comprehensive account of various barriers encountered in delivering the anti-cancer agent, the suitability of NLC to deliver anti-cancer agent, the techniques employed for the fabrication of NLC, its structure, along its characterization. The main emphasis has given a break worth to overcome barriers in delivering chemotherapeutic through NLC so far; a number of qualitative literatures have been included in this review. Further, the study describes the stability issue associated with the long-term storage of NLC. Conclusion: The NLCs systems offer a great potential to target various anti-cancer agents suffering from low solubility, non-specificity, and severe adverse effects. The NLC system's development can overcome barriers encountered in delivering anti-cancer agents and improve its efficacy in various melanoma types.

Stabilization of networked switched affine systems with event-triggered strategy

Using an event-based switching law, we address the stability issue for continuous-time switched affine systems in the network environment. The state-dependent switching law in terms of the region function is firstly developed. We combine the region function with the event-triggering mechanism to construct the switching law. This can provide more candidates for the selection of the next activated subsystem at each switching instant. As a result, it is possible for us to activate the appropriate subsystem to avoid the sliding motion. The Zeno behavior for the switched affine system can be naturally ruled out by guaranteeing a positive minimum inter-event time between two consecutive executions of the event-triggering threshold. Finally, two numerical examples are given to demonstrate the effectiveness of the proposed method.

Distributed Secondary Control of Islanded Microgrids for Fast Convergence Considering Arbitrary Sampling

This paper proposes a novel distributed secondary control of MGs for fast convergence considering asynchronous sampling. With the employment of the algorithm, optimal power sharing and voltage restoration are implemented simultaneously. First, the hierarchical control objectives concerned with economic operation and voltage quality are introduced. Then, the execution process of the fast convergence algorithm is described for weighted average state estimation, with the illustration of corresponding features and the application in cooperative control. Further, the relevant stability issue is discussed based on large-signal dynamic modeling and a sufficient stability condition is derived based on the Lyapunov–Krasovskii theory. Our approach offers superior reliability, flexibility and robustness because of the loose implementation in terms of its performance concern, which is essential when the distributed consensus protocol is likely to yield toward deviation or even instability under arbitrary sampling and delays. The effectiveness of the proposed methodology is verified via simulations.