Symmetrizing cathode-anode response to speed up charging of nanoporous supercapacitors

Asymmetric behaviors of capacitance and charging dynamics in the cathode and anode are general for nanoporous supercapacitors.Understanding this behavior is essential for the optimal design of supercapacitors.Herein,we perform constant-potential molecular dynamics simulations to reveal asymmetric features of porous supercapacitors and their effects on capacitance and charging dynamics.Our simulations show that,counterintuitively,charging dynamics can be fast in pores providing slow ion diffusion and vice versa.Unlike electrodes with singlesize pores,multi-pore electrodes show overcharging and accelerated co-ion desorption,which can be attributed to the subtle interplay between the dynamics and charging mechanisms.We find that capacitance and charging dynamics correlate with how the ions respond to an applied cell voltage in the cathode and anode.We demonstrate that symmetrizing this response can help boost power density,which may find practical applications in supercapacitor optimization.

Non-Surgical Endodontic Retreatment of Anterior Tooth with a Large Periapical Lesion and Extruded Guta Percha with 36 Months Follow-Up: A Case Report

Root canal treatment failure depends on many factors. Overfillings, insufficient fillings, missing canals, failure to provide a complete apical plug, and impermeability of coronal restoration are some of them. Failed root canal treatment may not always manifest itself immediately after treatment. Sometimes, root canal treatments, which have not been done well, can manifest themselves with extensive lesions and severe pain in the apical after a long time. Apical resection may be considered as a solution in lesions that are too large to be treated, but retreatment without surgery should be attempted beforehand. Thus, the patient may have recovered from unnecessary surgical procedures and treated with a more conservative method. This case presents the non-surgical retreatment of a left lateral tooth with a large periapical lesion with extruded gutta percha followed by a 36-month follow-up.

A PML Method for Electromagnetic Scattering from Two-dimensional Overfilled Cavities

In this paper, we consider electromagnetic scattering problems for two-dimensional overfilled cavities. A half ringy absorbing perfectly matched layer （PML） is introduced to enclose the cavity, and the PML formulations for both TM and TE polarizations are presented. Existence, uniqueness and convergence of the PML solutions are considered. Numerical experiments demonstrate that the PML method is efficient and accurate for solving cavity scattering problems.

High-frequency lacustrine sequence stratigraphy of clastic lakes:lessons from ancient successions

Sequence stratigraphic concepts and methods provide novel tools for performing stratigraphic analysis,allowing us to improve our understanding of depositional models and basin evolution.Main controls and depositional elements(e.g.,surfaces,systems tracts,parasequences,etc.)recognized in conventional sequence stratigraphy are designed for marine-related systems.In contrast,the sequence stratigraphy of lacustrine successions is much more complex and poorly understood,because it is not driven by sea-level changes,but by a complex interaction between tectonics and high-frequency climatic cycles.The comprehensive analysis of the water balance of lacustrine systems allows the recognition of three types of lake conditions:Underfilled,balanced-fill and overfilled lakes.Understanding the lake conditions in ancient successions is fundamental for unraveling lacustrine sequence stratigraphy,since these conditions effectively control water salinity,internal stacking pattern and the characteristics of systems tracts.Underfilled lakes are hydrologically closed lakes,and consequently,the lake-level can highly fluctuate,driven by high-frequency wet-dry climatic cycles.During wet periods,rivers supply water and sediments,resulting in fining-and thinning-upward elementary depositional sequences(EDS's)accumulated during the transgressive systems tract(TST).In contrast,dry periods are characterized by a relative lake-level fall with the subaerial exposure of lake margin areas during the regressive systems tract(RST).Lake water salinity can fluctuate from brackish to hypersaline.Balanced-fill lakes are partially closed lakes,and consequently,they have characteristics of both underfilled and overfilled lakes.During the TST,the lake is in underfilled condition,and consequently,the introduction of water and sediment will accumulate a fining-upward interval until reaching the spill point during the maximum flooding.The RST is accumulated under an overfilled lake condition,with coarseningupward progradational littoral deltas and related subaqueous delta deposits.Lake water salinity fluctuates from brackish to freshwater.Overfilled lakes are hydrologically open lakes.Most deposits accumulate during the RST,forming coarsening-upward progradational littoral deposits,with associated subaqueous deltas.All overfilled lakes are freshwater lakes.Subsidence is crucial for allowing the long-term preservation of lacustrine deposits.Lakes can temporarily store water and sediments in areas that lack subsidence,but these deposits will not be preserved in the stratigraphic record.Consequently,two types of lakes are recognized:1)subsiding lakes,which have permanent accommodation space and 2)hanging lakes,having temporary accommodation space.Although they cannot permanently store sediments,hanging lakes are fundamental for lacustrine sequence stratigraphy,since they can flood subsiding lakes with the near-instantaneous release of a substantial volume of water,creating favorable conditions for the accumulation of organic-rich shales.This rapid flooding from hanging lakes induced a forced transgression(FT),which is a large-scale rapid transgression(xenoconformity)not related to the normal sediment and water supply from local source areas.

Numerical Solutions of the Electromagnetic Scattering by Overfilled Cavities with Inhomogeneous Anisotropic Media

In this paper,the electromagnetic scattering from overfilled cavities with inhomogeneous anisotropic media is investigated.To solve the scattering problem,a Petrov-Galerkin finite element interfacemethod on non-body-fitted grids is presented.We reduce the infinite domain of scattering to a bounded domain problem by introducing a transparent boundary condition.The level set function is used to capture complex boundary and interface geometry that is not aligned with the mesh.Nonbody-fitted grids allow us to save computational costs during mesh generation and significantly reduce the amount of computer memory required.The solution is built by connecting two linear polynomials across the interfaces to satisfy the jump conditions.The proposed method can handle matrix coefficients produced by permittivity and permeability tensors of anisotropic media.The final linear system is sparse,making it more suitable for most iterative methods.Numerical experiments show that the proposed method has good convergence and realizability.Meanwhile,we discover that the absorbing properties of anisotropic media clearly and positively influence the reduction of radar cross section.It has also been demonstrated that the method can achieve second-order accuracy.

Analysis and Numerical Solution of Transient Electromagnetic Scattering from Overfilled Cavities

A hybrid finite element(FEM)and Fourier transform method is imple-mented to analyze the time domain scattering of a plane wave incident on a 2-D over-filled cavity embedded in the infinite ground plane.The algorithm first removes the time variable by Fourier transform,through which a frequency domain problem is ob-tained.An artificial boundary condition is then introduced on a hemisphere enclosing the cavity that couples the fields from the infinite exterior domain to those inside.The exterior problem is solved analytically via Fourier series solutions,while the interior region is solved using finite element method.In the end,the image functions in fre-quency domain are numerically inverted into the time domain.The perfect link over the artificial boundary between the FEM approximation in the interior and analytical solution in the exterior indicates the reliability of the method.A convergence analysis is also performed.

A Hybrid Finite Element-Laplace Transform Method for the Analysis of Transient Electromagnetic Scattering by an Over-Filled Cavity in the Ground Plane

A hybrid finite element-Laplace transform method is implemented to analyze the time domain electromagnetic scattering induced by a 2-D overfilled cavity embedded in the infinite ground plane.The algorithm divides the whole scattering domain into two,interior and exterior,sub-domains.In the interior sub-domain which covers the cavity,the problem is solved via the finite element method.The problem is solved analytically in the exterior sub-domain which slightly overlaps the interior subdomain and extends to the rest of the upper half plane.The use of the Laplace transform leads to an analytical link condition between the overlapping sub-domains.The analytical link guides the selection of the overlapping zone and eliminates the need to use the conventional Schwartz iteration.This dramatically improves the efficiency for solving transient scattering problems.Numerical solutions are tested favorably against analytical ones for a canonical geometry.The perfect link over the artificial boundary between the finite element approximation in the interior and analytical solution in the exterior further indicates the reliability of the method.An error analysis is also performed.