三维各向异性超常媒质交错结构的亚波长谐振特性研究

以填充各向异性超常媒质矩形波导中的电磁场解为基础,通过建立与求解填充各向异性超常媒质交错结构的矩形谐振腔的谐振方程,深入研究了三维各向异性超常媒质交错结构的亚波长谐振特性.结果发现,三维各向异性超常媒质交错结构的亚波长谐振条件具有更为多样性的物理解,在固定参数下,其物理解的个数往往超过一个,还针对谐振结构的横向尺寸对亚波长谐振条件的影响进行了讨论.结果表明,随着横向尺寸的减小亚波长谐振条件的物理解数量将逐渐增多直至趋于无穷.这意味着即使超常媒质的本构参数无法控制,仍然可以通过调节谐振结构的横向尺寸来得到亚波长谐振腔. 关键词： 各向异性 超常媒质 交错结构 亚波长谐振     

Superfluidity of indirect excitons vs quantum Hall correlation in double Hall systems: Different types of physical mechanisms of correlation organization in Hall bilayers

Bilayer Hall systems can be divided into two groups—with and without tunneling of carriers across the barrier between layers. We demonstrate that these both classes differ in topology sense which leads to the distinct quantum Hall hierarchy. In the case of forbidden interlayer carrier tunneling we developed the Metropolis Monte Carlo simulation for an energy competition of the reentrant integer quantum Hall state against the superfluid Bose Einstein condensate of indirect excitons in double-layer 2D Hall systems, GaAs/GaAlAs/GaAs and b-graphene/hBN/b-graphene, with complementary layer filling, ${\nu }_{bot}+{\nu }_{top}=1$. The resulted phase diagrams for both systems have been determined in consistence with the experimental data.     

Surface Assembly of DNA Origami on a Lipid Bilayer Observed Using High-Speed Atomic Force Microscopy

The micrometer-scale assembly of various DNA nanostructures is one of the major challenges for further progress in DNA nanotechnology. Programmed patterns of 1D and 2D DNA origami assembly using specific DNA strands and micrometer-sized lattice assembly using cross-shaped DNA origami were performed on a lipid bilayer surface. During the diffusion of DNA origami on the membrane surface, the formation of lattices and their rearrangement in real-time were observed using high-speed atomic force microscopy (HS-AFM). The formed lattices were used to further assemble DNA origami tiles into their cavities. Various patterns of lattice–tile complexes were created by changing the interactions between the lattice and tiles. For the control of the nanostructure formation, the photo-controlled assembly and disassembly of DNA origami were performed reversibly, and dynamic assembly and disassembly were observed on a lipid bilayer surface using HS-AFM. Using a lipid bilayer for DNA origami assembly, it is possible to perform a hierarchical assembly of multiple DNA origami nanostructures, such as the integration of functional components into a frame architecture.     

Transient swelling-induced finite bending of hydrogel-based bilayers: analytical and FEM approaches

Hydrogels with their time-dependent intrinsic behaviors have recently been used widely in soft structures as sensors/actuators. One of the most interesting structures is the bilayer made up of hydrogels which may undergo swelling-induced bending. In this work, by proposing a semi-analytical method, the transient bending of hydrogel-based bilayers is investigated. Utilizing nonlinear solid mechanics, a robust semi-analytical solution is developed which captures the transient finite bending of hydrogel-based bilayers. Moreover, the multiphysics model of the hydrogels is implemented in the finite element method (FEM) framework to verify the developed semi-analytical procedure results. The effects of different material properties are investigated to illustrate the nonlinear behavior of these structures. The von-Mises stress contour extracted from FEM shows that the critical area of these soft structures is at the interface of the layers which experiences the maximum stress, and this area is most likely to rupture in large deformations.     

A new black to highly transmissive switching bilayer polymer composite films with electroactive pEA as a color buffer layer for improving electrochromic stability

Two reported D-A-D monomers based on 3,4-ethylenedioxythiophene (EDOT) were selected for electrochemical copolymerization to obtain copolymer film, named pRG. Then, a soluble polymer poly[3,4-ethylenedioxythiophene-alt-3,4-bis([2-ethylhexyl]oxy)thiophene] (pEA) based on the EDOT derivative was screened out, which is complementary to the absorption trough of the pRG film in visible region and matched with its working potential. The bilayer composite film pRG/pEA was obtained by spinning pEA basement membrane on fluorine doped tin oxide (FTO) coated glass surface, and then in situ electrochemical polymerization of pRG film. Compared to the pRG monolayer film, the bilayer composite film shows a more saturated black color in the neutral state and significant improvement on cyclic stability (only decreased by 1.7% after 250 cycles, while pRG film decreased by 17.1%). The introduction of pEA buffer layer not only achieves the full spectral absorption of the composite film in the visible region, but also significantly improves the cyclic stability of the bilayer composite film. The assembled EC prototype device based on the pRG/pEA composite film exhibits a “black to high transmission” reversible switch. Finally, this method combining electrochemical copolymerization, spin-coating, lamination and other methods provides a new research idea for designing and preparing black to transmissive electrochromic materials.     

4D Biofabrication of Mechanically Stable Tubular Constructs Using Shape Morphing Porous Bilayers for Vascularization Application

This study reports the fabrication of highly porous electrospun self-folding bilayers, which fold into tubular structures with excellent mechanical stability, allowing them to be easily manipulated and handled. Two kinds of bilayers based on biocompatible and biodegradable soft (PCL, polycaprolactone) and hard (PHB, poly-hydroxybutyrate) thermoplastic polymers have been fabricated and compared. Multi-scroll structures with tunable diameter are obtained after the shape transformation of the bilayer in aqueous media, where PCL-based bilayer rolled longitudinally and PHB-based one rolled transversely with respect to the fiber direction. A combination of higher elastic modulus and transverse orientation of fibers with respect to rolling direction allowed precise temporal control of shape transformation of PHB-bilayer – stress produced by swollen methacrylated hyaluronic acid (HA-MA) do not relax with time and folding is not affected by the fact that bilayer is fixed in unfolded state in cell culture medium for more than 1 h. This property of PHB-bilayer allowed cell culturing without a negative effect on its shape transformation ability. Moreover, PHB-based tubular structure demonstrated superior mechanical stability compared to PCL-based ones and do not collapse during manipulations that happened to PCL-based one. Additionally, PHB/HA-MA bilayers showed superior biocompatibility, degradability, and long-term stability compared to PCL/HA-MA.