Honeycomb Lattice Structure Research Articles

Developing a Synthesis Process for Large‐Scale h‐BN Nanosheets Using Magnetron Sputtering and Heat Annealing

Hexagonal boron nitride (h‐BN) is an extensively investigated 2D material with exceptional quantum effects, which renders it promising for use in next‐generation nanoelectronic devices. However, the synthesis of single‐ or few‐layer h‐BN nanosheets with large‐area single‐crystal structures is extremely challenging. In this article, a new method is presented for synthesizing h‐BN on a Cu substrate via magnetron sputtering and heat annealing. Three samples with different radio‐frequency (RF) power levels are prepared to evaluate the effect of RF power on h‐BN nanosheet synthesis. Under a higher RF power, the B‐to‐N bonding ratio is closer to 1:1 and further reduces the full width at half maximum of X‐Ray photoelectron spectroscopy B1s and N1s narrow spectra. Heating at 1000 °C reveals white domains with 60° facets, which may correspond to the hexagonal honeycomb lattice structure of h‐BN. Cross‐sectional observations show that a layered structure comprising 10–20 layers forms along the Cu interface. The elemental composition ratio and bonding states reveal the presence of equal amounts of N and B as well as a single peak derived from the B–N bond. Meanwhile, the E2g mode of h‐BN's six‐membered ring structure is indicated at 1364.6 cm−1, thus demonstrating the successful synthesis of an h‐BN film.

Finite element simulation of femoral stems lightweighted with re-entrant honeycomb lattice structure

Artificial hip joints are used to replace damaged or diseased natural joints. When the stress that is typically applied to the bone changes because the implant and bone are different in stiffness, a phenomenon known as stress shielding occurs. Stress shielding can lead to bone weakening through reduced density and aseptic loosening in the long term. Studies are ongoing to overcome this phenomenon through geometric design, the use of materials with a low modulus of elasticity, or latticed implants. In this study, the effect of lightening the hip prosthesis with lattice structures on stress shielding is investigated using finite element simulation. The femoral stem of a solid hip prosthesis was lightweighted, with a re-entrant honeycomb auxetic cellular lattice structure, and structural analysis was performed. Two different lattice orientations were used, and it was observed that the stress distribution was more homogeneous in both orientations. In these femoral stems, which can be easily produced using additive manufacturing methods, a volume reduction of up to 16% was achieved. The stress transmitted to the bone increased by more than 36%, depending on the orientation, which is a promising result for reducing the stress shield effect.

Topological design factor optimization in the development of periodic‐type honeycomb lattice structure on the carbon fiber reinforced polyethylene terephthalate glycol composite

AbstractIn most of the automobile and aerospace materials, cellular structures are extensively used due to their lightweight and high energy absorption capabilities. Naturally available animal bones and plant stems are light in weight due to their natural cellular structures. This may inspire various researchers for integrating the various lattice structures such as beam, planar, triply periodic minimal surfaces, and voronoi structures on the various structural materials. The development of lattice structures using 3D printing technology has opened up major attention towards fabricating lightweight components without any complications. In this study, the detailed crashworthiness responses such as compressive strength was optimized in terms of varying the topology‐related factors on the carbon fiber reinforced polyethylene terephthalate glycol (CF/PETG) composite. The experimentation was conducted concerning variable topology factors such as shell thickness, unit cell type, wall thickness (WT), unit cell orientation (UCO), skewing angle, and unit cell size. The model was examined and optimized by means of the Taguchi optimization technique. The crashworthiness response was analyzed using the compression test and moreover, this experimental response is used for the optimization processes. From the observation, the topology factors which contributed more for the higher compressive strength will be UCO of 65.47% and WT of 15.20%. Results of the regression study show that the R square value with concern to the compressive strength will be 92.74%. The optimized design parametric condition for CF/PETG composite established a higher compressive strength of 41.179 MPa, From the overall results, it is clear that the variation in the topology factors has developed a huge and favorable impact on the mechanical characteristics of the lattice‐structured CF/PETG polymer composite.Highlights Hexagonal Lattice structure incorporation on the carbon fiber reinforced PETG composite. Design optimization on the compressive properties. Taguchi optimization is performed on design‐based lattice structures. Unit cell orientation has higher percentage contribution on compressive strength.

Compressive and tensile behaviours of 3D hybrid auxetic-honeycomb lattice structures

Lattice structures have the potential for application in tensile conditions. However, limited studies have addressed tensile behaviours of such structures and compared them with their compressive behaviours. In this paper, re-entrant structure as the foundation was selected to develop new 3D hybrid auxetic honeycomb lattice structures, each characterized by a unique unit cell configuration that features interconnected centre auxetic honeycomb, differentiating it from 2D hybrid auxetic honeycomb structures. A series of uniaxial quasi-static tensile and compressive tests, followed by simulations were conducted on these structures to investigate and compare their energy absorption characteristics. The results show that there were significant differences between these structures in terms of their mechanical behaviours under tension and compression. Especially, the smallest value of energy absorption under tensile load was 86% higher than the largest value under compressive load. The stiffnesses of these lattice structures under tensile loading were about 84–122 times of those of the identical corresponding structures when they were compressed. Meanwhile, the progressive stretching, buckling and collapse mechanisms observed in these structures exhibited excellent stiffnesses and energy absorptions under tensile and compressive load compared to traditional 3D auxetic as the basic structure. The outer frame structure of lattice structures had a direct influence on Poisson's ratio. The work indicates that the stiffness and energy absorption of the traditional 3D auxetic structure can be enhanced by embedding auxetic and honeycomb umbrella shaped elements.

Scattering quantum walk framework for two-dimensional materials: The case of honeycomb lattice structures

Scattering quantum walk framework for two-dimensional materials: The case of honeycomb lattice structures

Absence of Topological Protection of the Interface States in Z_{2} Photonic Crystals.

Inspired from electronic systems, topological photonics aims to engineer new optical devices with robust properties. In many cases, the ideas from topological phases protected by internal symmetries in fermionic systems are extended to those protected by crystalline symmetries. One such popular photonic crystal model was proposed by Wu and Hu in 2015 for realizing a bosonic Z_{2} topological crystalline insulator with robust topological edge states, which led to intense theoretical and experimental studies. However, a rigorous relationship between the bulk topology and edge properties for this model, which is central to evaluating its advantage over traditional photonic designs, has never been established. In this Letter, we revisit the expanded and shrunken honeycomb lattice structures proposed by Wu and Hu and show that they are topologically trivial in the sense that symmetric, localized Wannier functions can be constructed. We show that the Z and Z_{2} type classifications of the Wu-Hu model are equivalent to the C_{2}T protected Euler class and the second Stiefel-Whitney class, respectively, with the latter characterizing the full valence bands of the Wu-Hu model, indicating only a higher order topological insulator. Additionally, we show that the Wu-Hu interface states can be gapped by a uniform topology preserving C_{6} and T symmetric perturbation, which demonstrates the trivial nature of the interface. Our result reveals that topology is not a necessary condition for the reported helical edge states in many photonics systems and opens new possibilities for interface engineering that may not be constrained by topological considerations.

Investigation of additive manufactured micro-lattice structures for defence applications

Abstract This study investigates the blast mitigation capabilities of A286 steel micro-lattice structures produced through additive manufacturing. The research explores the effects of different manufacturing conditions, such as stress relief and heat treatment, on the mechanical properties and blast resistance of honeycomb and gyroid lattice structures in correlation with armour steel structures. Comprehensive evaluations, including surface morphology, corrosion resistance, and compressive residual stress analysis, reveal notable findings for micro-lattice structures. Micro-lattice structures demonstrated 57.23% higher corrosion resistance compared to conventional materials, presently available in the form of rolled homogeneous armour, medium hardness armour, and high-nitrogen steel. Additionally, honeycomb lattice structures exhibit compressive residual stresses of up to 581.90 MPa, providing significant advantages in blast mitigation potential. These results underscore the significance of lattice geometry, material microstructure, and residual stress in enhancing blast resistance. The research offers valuable insights into optimizing additive manufactured structures as an alternative modular solution for defence applications.

Nearly Zero Ultra-Flattened Dispersion in Octagonal Photonic Crystal Fiber

The low confinement losses, relatively high nonlinearity, and wideband ultra-flattened chromatic dispersion are the crucial properties of the PCFs. Thus, in this research, a comprehensive study has been conducted to design a novel Octagonal PCF (Photonic Crystal Fiber) microstructure with an ultra-flattened dispersion profile through a vast range of optical communication band wavelengths with a large negative dispersion of nearly 0.6635 ps/nm/km at 1550 nm. This PCF design and simulative study have been made by using COMSOL multi-physics. The guiding features of the fiber have been analyzed numerically to solve the Maxwell equation of electromagnetic field by using the full vector finite element method with cylindrically perfect to match layer for strongly absorb the outgoing waves from the computational region. Moreover, Octagonal rings in the cladding region provide better confinement and flattened dispersion in O-band (1260 nm-1360 nm) and C-band (1530 nm-1565 nm) in comparison to honeycomb or hexagonal lattice structures. Our proposed model has a nearly zero ultra-flattened dispersion of ± 0.3028 ps/nm/km in a 1290 nm to 1620 nm with wavelength range (320 nm flat band) and low confinement loss is less than 10-7 dB/km in the entire band of interest. Furthermore, this research has been presented a 7.2 μm2 effective area which is smaller than other reported fibers at 1550 nm wavelength.

Tunable topological phase transition in the telecommunication wavelength

Recent progress in the Valley Hall insulator has demonstrated a nontrivial topology property due to the distinct valley index in 2D semiconductor systems. In this work, we propose a highly tunable topological phase transition based on valley photonic crystals. The topological phase transition is realized by the inversion symmetry broken due to the refractive index change of structures consisting of optical phase change material (OPCM) with thermal excitation of different sites in a honeycomb lattice structure. Besides, simulations of light propagation at sharp corners and pseudo-spin photon coupling are conducted to quantitatively examine the topological protection. Compared with other electro-optical materials based on reconfigurable topological photonics, a wider bandwidth and greater tunability of both central bandgap frequency and topological phase transition can happen in the proposed scheme. Our platform has great potential in practical applications in lasing, light sensing, and high-contrast tunable optical filters.

Compressive properties of novel hybrid-dimensional gyroid lattice structure

This work proposed a novel hybrid method based on the three-dimensional gyroid lattice structure and two-dimensional honeycomb lattice structure. We choose a commercial stereolithography (SLA) printer to fabricate the lattice samples with 405 nm photosensitive resin material. Axial quasi-static compression is selected to test the mechanical properties. According to the experimental results, the multiple deformation behaviors and reinforcement of stress response at the post-plateau stage are observed in hybrid lattice samples. By the proportion of substructure, the compressive strength and energy absorption of the hybrid-dimensional lattice can be tailored, which is suitable to act as an effective energy absorber for various applications.

Effect of pH and Concentration of Dopamine Solution on the Deposited Polydopamine Film and the Prepared Graphene-like Material

In this study, according to the acquired polydopamine deposition rates, polydopamine films with equal thickness were prepared under different conditions on SiO2 substrates. Subsequently, we investigated the influence of dopamine solution pH and concentration on the formation of surface aggregates of the deposited polydopamine films. Assumptions were made to explain how pH and concentration execute their effects. Based on the optimized parameters, a continuous and smooth polydopamine film with a thickness of about 14 nm and a roughness of 1.76 nm was fabricated on a silicon dioxide substrate, through the deposition for 20 minutes in a dopamine solution with a concentration of 1.5 mg/mL and a pH of 8.2. The prepared polydopamine film was then employed as a precursor and subjected to a high-temperature process for the carbonization and graphitization of the film. Raman spectroscopy analysis indicated that the resulting graphene-like film had fewer structural defects in comparison with previous works and the results of XPS indicated that most of the carbon atoms were bound into the cross-linked honeycomb lattice structure. The prepared graphene-like material also exhibited high electrical conductivity and satisfying mechanical elasticity.

Sublattice-enriched tunability of bound states in second-order topological insulators and superconductors

Bound states at sharp corners have been widely viewed as the hallmark of two-dimensional second-order topological insulators and superconductors. In this work, we show that the existence of sublattice degrees of freedom can enrich the tunability of bound states on the boundary and hence lift the constraint on their locations. We take the Kane-Mele model with honeycomb-lattice structure to illustrate the underlying physics. With the introduction of an in-plane exchange field to the model, we find that the boundary Dirac mass induced by the exchange field has a sensitive dependence on the boundary sublattice termination. We find that the sensitive sublattice dependence can lead bound states to emerge at a specific type of boundary defects named as sublattice domain walls if the exchange field is of ferromagnetic nature, even in the absence of any sharp corner on the boundary. Remarkably, this sensitive dependence of the boundary Dirac mass on the boundary sublattice termination allows the positions of bound states to be manipulated to any place on the boundary for an appropriately-designed sample. With a further introduction of conventional s-wave superconductivity to the model, we find that, no matter whether the exchange field is ferromagnetic, antiferromagnetic, or ferrimagnetic, highly controllable Majorana zero modes can be achieved at the sublattice domain walls. Our work reshapes the understanding of boundary physics in second-order topological phases, and meanwhile opens potential avenues to realize highly controllable bound states for potential applications.

Review on sustainable synthesis of semi-amorphous Ti-BDS MOF material, activated carbon, and graphene

The ability to replace non-renewable, low-atom economy chemicals with an efficient catalyst that can join the reactants to generate the required product makes catalysis a useful tool for sustainable synthesis. Through careful designs toward sustainability, inspiring efforts are made in bioproducts and self-sustaining technologies for the integrated synthesis of value-added goods and energies. In this paper, we review a new Ti-BDS MOF, activated carbon, Al-based MOF, and Graphene, because it is readily made at room temperature, MIL-125 is extensively used. It is prepared environmentally, energetically, and economically (3E) Therefore, it is theoretically scalable and has long-term sustainability. Furthermore, by combining Ti-BDC containing g-C3N4 and Ag3PO4, unique Ti-BDC-based ternary photo-catalysts were effectively created. It provides a summary of the application of high-throughput (HT) approaches in the domain of porous aluminumMOFs for both drug discovery and synthesis optimization. One of the carbon allotropes is graphene, which has its carbon atoms organizedin a single sheet. These atoms of carbon are arranged in a two-dimensional honeycomb lattice structure. Graphene is an electrically, mechanically, thermally, and structurally innovative material. The characteristics of graphene produced from biomass precursors are comparable to those of graphene from traditional sources. For the manufacture of biofuels and many other high-value goods, activated carbon is a promising and long-term solid catalyst.

Free Vibration Characteristics of Multi-Material Lattice Structures

This paper presents a modal analysis of honeycomb and re-entrant lattice structures to understand the change in natural frequencies when multi-material configuration is implemented. For this purpose, parallel nylon ligaments within re-entrant and honeycomb lattice structures are replaced with chopped and continuous carbon fibre to constitute multi-material lattice configurations. For each set, the first five natural frequencies were compared using detailed finite element models. For each configuration, three different boundary conditions were considered, which are free–free and clamping at the two sides that are parallel and perpendicular to the vertical parts of the structure. The comparison of the natural frequencies was based on mode-shape matching using modal assurance criteria to identify the correct modes of different configurations. The results showed that the natural frequency of the multi-material configurations increases from 4% to 18% depending on the configuration and material.

Black phosphorous-based human-machine communication interface

Assistive technology involving auditory feedback is generally utilized by those who are visually impaired or have speech and language difficulties. Therefore, here we concentrate on an auditory human-machine interface that uses audio as a platform for conveying information between visually or speech-disabled users and society. We develop a piezoresistive tactile sensor based on a black phosphorous and polyaniline (BP@PANI) composite by the facile chemical oxidative polymerization of aniline on cotton fabric. Taking advantage of BP’s puckered honeycomb lattice structure and superior electrical properties as well as the vast wavy fabric surface, this BP@PANI-based tactile sensor exhibits excellent sensitivity, low-pressure sensitivity, reasonable response time, and good cycle stability. For a real-world application, a prototype device employs six BP@PANI tactile sensors that correspond to braille characters and can convert pressed text into audio on reading or typing to assist visually or speech-disabled persons. Overall, this research offers promising insight into the material candidates and strategies for the development of auditory feedback devices based on layered and 2D materials for human-machine interfaces.

Topological Valley Transport of Elastic Waves Based on Periodic Triangular-Lattices

Topological transports of elastic waves have attracted much attention because of their unique immunity to defects and backscattering-suppression ability. Periodic lattice structures are ideal carriers of elastic-wave transports due to their ability to manipulate elastic waves. Compared with honeycomb-lattice structures, the wave-guide-path designs of triangular-lattice structures have higher flexibility. In this paper, topological transports of elastic waves in the periodic triangular-lattice structure are explored. It is shown that differences between intra-coupling and inter-coupling radii can cause the destruction of the effective spatial inversion symmetry, which gives rise to the valley Hall phase transition and the forming of topological edge states. Utilizing valley Hall effect, topological transports of elastic waves traveling along linear and Z-shaped waveguides are realized with low scattering and immunity to defects. On this basis, the path-selection function of transports of elastic waves in periodic triangular-lattice structures is obtained. Topological valley Hall edge states of elastic waves in periodic triangular-lattice structures have a good application prospects in elastic-wave manipulations and communications.

A Novel Lattice Structure for Enhanced Crush Energy Absorption

the energy absorption capacity of a few common lattice structures printed out of PLA using fused deposition modeling and proposes an improved lattice structure. Simple cubic (SC), honeycomb (HC), body-centered cubic (BCC), and novel PeckGy80 (PG80) lattice structures were subjected to compressive tests. The quasi-static load-displacement behavior of lattice specimens was characterized in terms of specific energy absorption and crush load efficiency. The damage mechanisms were then related to energy absorption. Cracks and brittle fractures occurred in all lattice structures during the crush test. Different lattice structures induced different damage mechanisms, significantly affecting their energy absorption. SC lattice structure showed structural separation at a small displacement, rendering it an ineffective energy absorber. BCC and HC lattice structures demonstrated almost identical shear band failure modes. The PG80 lattice structure, although made of brittle PLA, displayed progressive failure from the bottom layer to the upper layers, exhibiting both a high peak load and stable post-yield behaviour. This damage mode enabled the PG80 lattice to be far superior in terms of specific energy absorption to HC, SC, and BCC lattice structures.

Dispersion, compatibility, and rheological properties of graphene-modified asphalt binders

Graphene is a 2D nanomaterial made of a monolayer, honeycomb lattice structure established by sp2-hybridized carbon atoms. Previous studies have indicated that graphene enhanced the high- temperature performance of neat asphalt binders. However, the intermediate- and low-temperature performance, dispersion, and compatibility of graphene-modified asphalt binders remain unclear. This study presents a comprehensive investigation on the above-mentioned research gaps of graphene-modified asphalt binders. A commercially available graphene was mixed with non-modified binder and SBS modified binder. The graphene dosage was varied as 0%, 0.3%, 0.65%, 1%, 1.5%, 2.5%, 5%, and 7% by the total weight of blends. The graphene dispersion was assessed by direct observation with an optical microscope and quantitative calculation through 2D image processing. The rotational viscosimeter was used to measure viscosity and to analyze the workability. The cigar tube test was conducted to examine the compatibility between graphene and asphalt binders. The Dynamic Shear Rheometer test was carried out on unaged, RTFO-aged, and PAV-aged specimens to obtain the rheological properties as well as to analyze the high- and intermediate-temperature performance. The bending beam rheometer was used to study the thermal cracking resistance at low temperature. The results showed that graphene up to 1.5% dosage was well dispersed in asphalt binders. The addition of graphene up to 1% dosage slightly increased the viscosity of asphalt binders. There was good compatibility between graphene and asphalt binders. Graphene significantly improved the rutting resistance, while had little adverse influence on the fatigue cracking and thermal cracking resistance up to 0.65% dosage addition. Thus, the optimum graphene dosage was 0.65% for both binder types. The findings showed the promising application of graphene in asphalt pavements.

Graphene Oxide‐Based Adsorbents for Organic‐Dyes Removal from Contaminated Water: A Review

AbstractPolluted organic dyes in water are considered as some of the most serious problems affecting humans. Adsorption techniques using traditional adsorbents such as clay, zeolite, silica, active carbon, and polymers are low cost, safe, and efficient for the treatment of organic dyes in contaminated water. However, traditional adsorbents usually have low adsorption capacity (qmax). To improve qmax, graphene oxide (GO) is considered as an excellent adsorption enhancer owing to its two‐dimensional single atomic layer material of sp2‐hybridised carbon atoms arranged in a honeycomb lattice structure with high surface area, high solubility, good chemical stability, strong mechanical strength, and excellent thermal stability. In this review, the synthesis and advantage results on improving the adsorption efficiency and qmax when applying GO‐based nanocomposites as nanosorbents for organic‐dye removal are systematised and discussed in detail.

Three woven structures of reduced graphene oxide conductive silk fabrics prepared by two different methods for electrical setting and sensing

Silk is widely used in flexible electronic equipment and intelligent textiles because of its well mechanical properties and bio-compatibility. Reduced graphene oxide is a two-dimensional carbon material with honeycomb lattice structure atoms and excellent electrical conductivity, which can give fabric a significant electrical conductivity. Herein, three types of RGO/Silk woven fabrics (satin, twill, and backed weaves) and two coating methods (screen printing and impregnating) were provided to explore the electrical properties, pressure sensing property and influence mechanism of silk surface characteristics. The results show the best preparation process of these two methods is five finishing times and 2 h reduction time. And the RGO/silk fabrics obtained by screen printing and impregnation have similar resistivity, but the RGO/silk fabrics obtained by screen printing provide better washing resistance. After nine washing cycles, the resistance of RGO/silk fabrics prepared by screen printing is 2 kΩ less than that obtained by impregnation. In addition, under the two methods, backed weave fabric shows the best conductivity, followed by twill and satin weave. Moreover, the RGO/Silk fabric sensor responds well to human motion, like finger bending and hand-holding objects. This work provides a train of thought and method for flexible conductive silk fabric.