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.

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.