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• A photoelectrochemical electrode was fabricated based on a graphene honeycomb film. • A fluorescent probe (AFP-PFBT-GOD) was synthesized for the detection current promotion. • This photoelectrochemical biosensor can sensitively detect alpha-fetoprotein by competitive immunoassay. • The photoelectrochemical biosensor has high detection sensitivity and good reliability. • The detection limit of alpha-fetoprotein is lower than 0.05 ng/mL. Alpha-fetoprotein (AFP) in adult serum often appears in early liver cancer. Therefore, early detection of an abnormal elevation of AFP concentration is important for the early diagnosis and treatment of primary liver cancer. In this work, a photoelectrochemical (PEC) electrode was fabricated for AFP-sensitive detection based on a reduced graphene oxide (rGO) honeycomb structure. After layer-by-layer bioconjugation, the immunoassay graphene electrode was modified with anti-AFP antibodies (Ab). Meanwhile, polymer nanoparticles (PFBT dots) were prepared via a nanoprecipitation method. In addition, the AFP was modified by using the PFBT dots and glucose oxidase (GOD), which formed a fluorescent probe (AFP-PFBT-GOD). By the competitive linkage of AFP and AFP-PFBT-GOD onto the anti-AFP modified honeycomb structure electrode, an immunosensor for AFP detection was obtained. During the PEC test, the electrons produced by the catalytic reaction of glucose and GOD can scavenge the photogenerated holes on the PFBT dots, which can reduce the recombination of photogenerated holes and electrons on the PFBT dots. The PEC immunosensor based on a rGO honeycomb structure exhibited a linear detection range of 0.05–100 ng/mL with a detection limit of 0.05 ng/mL. The excellent detection performance of the graphene PEC biosensor provides an opportunity for the early diagnosis of primary liver cancer. [ABSTRACT FROM AUTHOR]

Mathematical analysis on electromagnetic waves in photonic graphene, a photonic topological material which has a honeycomb structure, is one of the most important current research topics. By modulating the honeycomb structure, numerous topological phenomena have been observed recently. The electromagnetic waves in such media are generally described by the 2-dimensional wave equation. It has been shown that the corresponding elliptic operator with a honeycomb material weight has Dirac points in its dispersion surfaces. In this paper, we study the time evolution of the wave packets spectrally concentrated at such Dirac points in a modulated honeycomb material weight. We prove that such wave packet dynamics is governed by the Dirac equation with a varying mass in a large but finite time. Our analysis provides mathematical insights to those topological phenomena in photonic graphene. [ABSTRACT FROM AUTHOR]

Abstract Photonic graphene, a photonic crystal with honeycomb structures, has been intensively studied in both theoretical and applied fields. Similar to graphene which admits Dirac Fermions and topological edge states, photonic graphene supports novel and subtle propagating modes (edge modes) of electromagnetic waves. These modes have wide applications in many optical systems. In this paper, we propose a novel gradient recovery method based on Bloch theory for the computation of topological edge modes in photonic graphene. Compared to standard finite element methods, this method provides higher order accuracy with the help of gradient recovery technique. This high order accuracy is desired for constructing the propagating electromagnetic modes in applications. We analyze the accuracy and prove the superconvergence of this method. Numerical examples are presented to show the efficiency by computing the edge mode for the P -symmetry and C -symmetry breaking cases in honeycomb structures. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dispersion relation in honeycomb structure is calculated more accurately by taking advantage of the space periodicity of the core. • A flexural wave band gap is discovered and verified in the intact area of the honeycomb structure. • A new nondestructive method for detecting the debonding defect is proposed by using the band gap feature and the corresponding detection device is developed. Honeycomb structure is increasingly applied in various fields due to its high strength-to-weight ratios. However, due to the complex wave field in the structure, how to detect the defect accurately and efficiently is always an important problem. In this article, the honeycomb core, instead of being an obstacle to obtain the dispersion characteristic for traditional guided wave method, provides a way to calculate the wave propagation by being taken advantage of its space periodicity. By analyzing, simulating, and experimental testing, it is exhibited that there is a gap in the dispersion relation of the honeycomb structure which caused by the interaction between the local resonant vibration of the skins and the bending vibration of the structure. This gap disappears in the debonding area. Then a nondestructive testing method is proposed to detect the debonding defects based on this feature. The detection results of this proposed method are accord with that of ultrasonic C-scan. The results indicate that this method is suitable for detecting and locating the debonding defects in honeycomb structure with quite high sensitivity and efficiency, and it has a great potential to be widely used in filed test of honeycomb structure for its high feasibility. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) culture dish patterned with a microwell structure demonstrates a great application potential in biotechnology. This study reports on the easy fabrication of an ordered customizable honeycomb microwell array on the surface of polymer substrates including the commercial Petri dish to create a biological platform for cell culture. The fabrication method is based on a very simple solvent dip-coating technique and the methanol accumulation-induced phase separation in which a binary mixture of chloroform and methanol is used to induce a ternary solution and to guarantee the formation of the ordered pore array on the substrate. The surface topology of the honeycomb substrate is manipulated through varying the experimental conditions; notably, the obtained honeycomb structure is part of the substrate, which reveals an increase in the structure’s stability for the practical applications. Honeycomb-structured Petri dish fabricated using this method is applied as a scaffold for cell growth to demonstrate its potential in biomedical applications. [ABSTRACT FROM AUTHOR]

Organic semiconducting materials have attracted significant attention for use in optoelectronic devices, as they can significantly improve device performance. Herein, a donor–acceptor conjugated polymer (poly(isoindigo-thiopheneylbenzothiadiazole, PID-TBT) was synthesized, which has strong and broad absorption in the visible region (400–800 nm). The band gap of PID-TBT is 1.65 eV. The PID-TBT honeycomb film with a porous structure was easily fabricated by the breath figure method. Compared with the smooth PID-TBT film, the honeycomb film shows significant enhancement in light capture capability and the efficiency of photoelectric conversion. The reflectance of the honeycomb film is reduced by 7% and the photocurrent is tenfold higher than that of the smooth film. Apart from designing new molecules by complex reactions, this work demonstrated that photoelectric conversion can be easily improved by introducing micro or nanostructures into devices. [ABSTRACT FROM AUTHOR]

The synthesis of IrI 3 at high pressure in its layered honeycomb polymorph is reported. Its crystal structure is refined by single crystal X-ray diffraction. Faults in the honeycomb layer stacking are observed by single crystal diffraction, synchrotron powder diffraction, and transmission electron microscopy. A previously unreported "hyperhoneycomb" polymorph of IrI 3 (β -IrI 3), is also reported - Its structure in space group Fddd is determined by single crystal XRD. Both materials are highly-resistive diamagnetic semiconductors, consistent with a low spin d 6 configuration for Ir(III). The two- and three-dimensional Ir arrays in these polymorphs of IrI 3 are analogous to those found in the α- and β- polymorphs of Li 2 IrO 3 , although the Ir electron configurations are different. IrI 3 may be of future interest in the fabrication of new quantum materials. IrI 3 has been synthesized in both its previously reported layered form and in a previously unreported polymorphic form by a solid-state high-pressure method. Both of the crystal structures are refined by single crystal XRD. Their structural, physical, and optical absorption properties are characterized, which are consistent with the d 6 configuration of Ir(III) and their calculated electronic band structures. [Display omitted] • Honeycomb layered α-IrI 3 is successfully synthesized at a moderately high pressure. • A new IrI 3 polymorph with a 3D hyperhoneycomb structure is formed and discovered. • Both polymorphs are measured to be highly resistive diamagnetic semiconductors. [ABSTRACT FROM AUTHOR]

Highlights: [•] Composite films with honeycomb structure were formed at the liquid/liquid interface. [•] These films are composed of block copolymer PS-b-P2VP and Ag+ or ions. [•] Co-adsorption and self-assembly of polymer and the ions lead to the film formation. [•] Transformed metal nanoparticles exhibit high and durable catalytic activity. [ABSTRACT FROM AUTHOR]

Polycrystalline samples of a new solid solution Li 2 Ru 1- x Rh x O 3 have been synthesized at 1000 °C in oxygen. Miscibility is found to exist for 0.4 ≤ x ≤ 1. X-ray and neutron diffraction analyses show that the whole series possesses a monoclinic layered structure belonging to the C 2/ m space group with lattice constants decreasing with increasing Rh content. For 0 < x < 0.4, a two-phase mixture, both C 2/ m structures, is formed. Time of flight neutron data refinements produced ~20% Li–Rh site exchange in the end member, Li 2 RhO 3. Defect modeled Li 2 RhO 3 structure yielded a 15% density of stacking faults perpendicular to the honeycomb layers. Magnetization measurements give an effective moment that increases with x as expected, and spin-glass-like hysteresis is observed below 10 K for x ≠ 0,1. Seebeck measurements show all of the compositions to be p-type above 300 K. The resistivity, ρ (T) , is well fit by a power law, ρ (T) ∝ T − ν , where 4.7 ≤ ν ≤ 9 depending on the composition, as opposed to Arrhenius-type behavior. This provides support for an electronic density of states that varies with energy as a power law, as opposed to that found for semiconductors or systems exhibiting variable range hopping, where charge transport is dictated by energy gaps. New Honeycomb layered Li 2 Ru 1- x Rh x O 3 solid solution series was synthesized with a miscibility gap of 0 < x < 0.4, Thus synthesized solid solutions exhibit gapless transport properties reminiscent of semimetals and resistivity data follows ρ(T) = ρ 0 T − ν relationship where ν > 4 leading to power law density of states below 300 K. Image 1 • New honeycomb layered Li 2 Rh 1- x Rh x O 3 solid solution series was synthesized with a miscibility gap of 0.4 ≤ x ≤ 1. • Stacking Fault modeling through DIFFaX yielded a density of ~15% occurring perpendicular to LiRh 2 layers. • Spin-glass-like hysteresis is observed for all the solid solutions below ~ 10 K. • Low temperature T < 300 K resistivity measurements fit well to ρ (T) ∝ T − ν relationship. [ABSTRACT FROM AUTHOR]