Design Of Three-dimensional Structures Research Articles

ARTIFICIAL INTELLIGENCE WITH NEURAL NETWORKS NOBEL PRIZES IN PHYSICS AND CHEMISTRY 2024

John Joseph Hopfield began his career studying excitons in condensed matter physics, but his most important contributions were in the physics of computation and information, including his 1982 work on neural networks. Geoffrey Hinton, known as the “godfather” of artificial intelligence, laid the foundations for deep neural networks and developed the “backpropagation” method in 1986. These advances, along with Hopfield networks and the “Boltzmann machine”, constitute the beginning of artificial intelligence. David Baker is a pioneer in the design and prediction of three-dimensional protein structures, while Demis Hassabis has applied artificial intelligence to neuroscience. John Michael Jumper has investigated the use of AI to simulate protein folding and dynamics. Hopfield and Hinton received the 2024 Nobel Prize in Physics, and Baker, Hassabis and Jumper received the Nobel Prize in Chemistry, sparking debates on interdisciplinarity and academic degrees in the sciences.

Design of non-homogeneous three-dimensional ceramic lattice structures with interpenetrating epoxy resin for enhanced energy absorption and load-bearing performance

Lightweight, energy-absorbing materials with superior mechanical properties are vital for engineering. Interpenetrating phase composites (IPCs) of Al2O3 ceramic and epoxy resin exhibit enhanced performance via non-homogeneous lattice design. Compression tests showed over 60% strength improvement compared to single-phase materials, while bending tests highlighted greater load capacity. Non-homogeneous structures demonstrated superior energy absorption and load-bearing abilities. Epoxy resin enhanced toughness under compression but not bending. A bulletproof model validated the practical potential of IPCs, emphasizing their engineering applicability in optimizing material properties through tailored lattice designs.

Deep cryogenic silicon etching for 3D integrated capacitors: A numerical perspective

One promising approach to increase the capacity density of integral microcapacitors, microsupercapacitors, and microbatteries is three-dimensional structure design, where electrodes are exposed in three dimensions instead of conventional in-plane electrodes. Such structures include nanowires, nanotubes, nanopillars, nanoholes, nanosheets, and nanowalls. In this work, a cryogenic silicon etching process suitable for fabrication of structures with high electrode area is proposed. A numeric model of this process is experimentally calibrated and used for pillar array structure sidewall area optimization. The use of adaptive Runge–Kutta–Fehlberg time integrator allows to achieve almost linear overall computation complexity as a function of simulated etching time, despite the linear increase in conductance computation complexity with depth. A rule for choosing optimal geometric structure parameters under technological constraints is formulated. An optimized trefoil-like structure is proposed, resulting in a total 5.5% increase in sidewall area with respect to the hexagonal array of circular pillars, resulting in 20.33 sidewall area per unit chip area for 30 min long etch or 31.80 for 60 min long etch.

Design and optimization of pore structure in three-dimensional micro-nano hierarchical SnOx supercapacitor electrodes for enhanced ion diffusion

This paper introduced a novel continuous electrochemical synthesis strategy to address the challenges of slow ion/electron transport rates and low electrode reaction efficiency in Sn-based electrode materials. This approach leveraged the induction and confinement of bubble templates to assist atoms deposition, generating micron-sized tin skeletons. Subsequently, these skeletons were transformed into a secondary nanoporous structure through dissolution-deposition etching effects. From liquid-phase ions to metal skeletons to porous oxides, the sequential material transformations realized the innovative design of three-dimensional (3D) hierarchical structures. This strategy ingeniously exploited the diffusion advantages of the electrolyte in the micro-nano hierarchical structure to achieve the diffusion enhancement of ions, thus solving the “dead surface” problem in the energy storage process. This study revealed the thermodynamic and kinetic feasibility of the constructed 3D micro-nano hierarchical structure through electrochemical evaluations and theoretical calculations, and elucidated the constitutive relationship in which the electrochemical performance of the electrode materials was enhanced with decreasing pore size. In addition, design optimization of pore structures and modelling exploration of pore size limit values were conducted based on density functional theory (DFT) simulations. These simulations demonstrated the advantages of hierarchical structures with controllable pore sizes in facilitating electrolyte ion diffusion, predicting an optimal pore size of 55 μm for 3D hierarchical porous SnOx electrodes. The integration of this innovative structural design with simulation insights offered significant implications for enhancing the sluggish electrode reaction kinetics of metal oxide electrode materials, advancing the controllable fabrication of high-performance energy storage devices.

In situ three-dimensional reconstruction and gradient-induced design of ultrastable Zn metal anodes in Zn-Se batteries

Zinc-selenium batteries have high specific and volumetric capacities, but practical development faces key challenge in achieving stable zinc metal anodes, and avoiding zinc dendrite growth, hydrogen evolution reaction (HER) and corrosion. Here, a zinc foam substrate is employed to fabricate three-dimensional gradient electrodes Zn foam@Cu@CuSe2 (ZFCCS) with gradient change of zincophilicity and conductivity. Experimental observations and simulations collectively confirm that the three-dimensional structure and gradient design effectively homogenize interfacial ion flux and diminish local current density. This optimization of the zinc deposition path synergistically fosters high flux and deep deposition of zinc metal while simultaneously preventing dendrite growth. The results demonstrate that the developed ZFCCS electrode produces an excellent Coulombic efficiency of 99.5 % over 1000 plating/stripping cycles, and the corresponding symmetric cell provides an ultra-long dendrite-free cycle life of 800 h at 5 mA cm−2 and 2 mAh cm−2 with a low overpotential of 27.4 mV. In addition, the Zn-Se full cell based on the designed ZFCCS composite anode exerts superior stable cycle life (358.1 mAh g−1 at 2 A g−1 after 1000 cycles). Therefore, the gradient design strategy based on 3D electrodes will be a reference for high performance energy storage devices.

Design and testing of novel three-dimensional modular negative stiffness honeycomb structures as reusable crash absorbers

Conventional crash absorbers dissipate kinetic energy of impacts into plastic irreversible deformation, needing an immediate replacement to restore safety of the structure, highly increasing cost and inconvenience of the system. Aim of the present work was to develop innovative prototypes of reusable crash absorbers, able to withstand multiple collisions . A novel design was proposed, based on a modified Negative Stiffness Honeycomb (NSH) approach, using a three-dimensional modular layout with the objective of improving performance, reliability, and functionality of the device in repeated impacts. Two prototypes were manufactured to prove the concept. The first was produced in Nylon PA 6/66 by fused deposition modelling, while the second was obtained from laser-cut plates of stainless steel AISI 304. The nylon prototype was evaluated in cyclic static compression and dynamic impact tests, while the performance of the steel prototype was assessed only in impact tests. Results show improved values of energy absorption with respect to previous studies using bidimensional NSH energy absorbers and a highly reliable behaviour in multiple dynamic compression tests. Moreover, the nylon prototype featured a novel behaviour during impact tests, with autonomous delayed recovery of deformation after the collision. Our data show that three-dimensional modular NSH approach is effective in obtaining a reusable crash absorber, with improved performance and functionality compared to previously proposed design. This work can be considered a step forward in the search for alternative crash absorbers able to sustain multiple impactsbefore substitution, with potential advantages when their replacement is either impossible or too expensive.

Multiscale topology optimization for the design of spatially-varying three-dimensional lattice structure

This paper introduces three dimensional (3D) topology optimization specifically tailored for designing spatially-varying primitive-cubic (CP) type lattice structures. The developed design process consists of three steps: pre-processing, main processing, and post-processing. In the pre-processing step, a surrogate model between lattice geometry variables and effective elasticity tensor is constructed using an artificial neural network. This surrogate model is essential because it enables the quick calculation of the effective elasticity tensor of lattice microstructure. In the subsequent main processing step, multiscale topology optimization is performed. During this step, lattice microstructure size and rotation design variables are optimized together with the macrostructure density design variables. Macrostructures are designed using a well-established three-field density scheme with a SIMP formulation. Formulations for spatially-varying 3D lattice microstructure are newly developed based on a unit quaternion rotation representation scheme. In the final post-processing step, a spatially-varying microstructure is restored using a de-homogenization scheme, newly developed particularly for the primitive-cubic (CP) type 3D lattice structures. The effectiveness and robustness of the proposed formulations are validated through three design examples for the compliance minimization problem. Moreover, a designed lattice structure is fabricated using an additive manufacturing machine.

Tailoring 3D Star-Shaped Auxetic Structures for Enhanced Mechanical Performance

Auxetic lattice structures are three-dimensionally designed intricately repeating units with multifunctionality in three-dimensional space, especially with the emergence of additive manufacturing (AM) technologies. In aerospace applications, these structures have potential for use in high-performance lightweight components, contributing to enhanced efficiency. This paper investigates the design, numerical simulation, manufacturing, and testing of three-dimensional (3D) star-shaped lattice structures with tailored mechanical properties. Finite element analysis (FEA) was employed to examine the effect of a lattice unit’s vertex angle and strut diameter on the lattice structure’s Poisson’s ratio and effective elastic modulus. The strut diameter was altered from 0.2 to 1 mm, while the star-shaped vertex angle was adjusted from 15 to 90 degrees. Laser powder bed fusion (LPBF), an AM technique, was employed to experimentally fabricate 3D star-shaped honeycomb structures made of Ti6Al4V alloy, which were then subjected to compression testing to verify the modelling results. The effective elastic modulus was shown to decrease when increasing the vertex angle or decreasing the strut diameter, while the Poisson’s ratio had a complex behaviour depending on the geometrical characteristics of the structure. By tailoring the unit vertex angle and strut diameter, the printed structures exhibited negative, zero, and positive Poisson’s ratios, making them applicable across a wide range of aerospace components such as impact absorption systems, aircraft wings, fuselage sections, landing gear, and engine mounts. This optimization will support the growing demand for lightweight structures across the aerospace sector.

ORBITAL ANGULAR MOMENTUM-BASED SLOT ARRAY ANTENNA FOR MODERN APPLICATIONS

Millimeter waves are the most promising waves for different modern wireless communication networks. This is due to their ability to carry big data with enhanced channel capacity. However, mm-waves suffer from low propagation due to the effects of high attenuation factors with high frequencies. Therefore, in this work, a three-dimensional structural antenna design with a slot array is proposed to achieve high gain through a two-port feeding operation for orbital angular momentum applications of modern communication systems. Also, the improved bandwidth of the proposed antenna makes it an excellent candidate for fifth-generation (5G) communications systems. The antenna depends on two concentric structures with conductive circular cross-sectional area. The first structure is shaped as a three-dimensional cone with a cylindrical waveguide. The second structure is shaped as a circular disc with a circular aperture. The two parts of the proposed antenna are concentered to be fed with two discrete ports from the side with a 900phase difference. It is determined that the proposed antenna offers an exceptional gain to vary from 10dBi to 20dBi within the frequency band from 3GHz to 30GHz. It is realized that such enhancement after introducing a conductive circular reflector underneath the conductive cone. The antenna shows a matching impedance below -10dB over the entire frequency band of interest. The antenna radiation proprietors at 25GHz and 26GHz at the E-plane and H-plane are characterized. Finally, the antenna performance is validated using two software packages based on CST studio and HFSS algorithms.

Inverse Design of Self-Folding 3D Shells.

Self-folding is an emerging paradigm for the inverse design of three-dimensional structures. While most efforts have concentrated on the shape of the net, our approach introduces a new design dimension-bond specificity between the edges. We transform this design process into a Boolean satisfiability problem to derive solutions for various target structures. This method significantly enhances the yield of the folding process. Furthermore, by linearly combining independent solutions, we achieve designs for shape-shifting nets wherein the dominant structure evolves with varying external conditions. This approach is demonstrated through coarse-grained simulations on two examples of triangular and square nets capable of folding into multiple target shapes.

Coupling of bond-based peridynamics and continuous density-based topology optimization methods for effective design of three-dimensional structures with discontinuities

This study proposes continuous density-based three-dimensional topology optimization (TO) approaches developed by coupling the peridynamic theory (PD) with optimality criteria (OC) and proportional approach (PROP). These frameworks, abbreviated as PD-OC-TO and PD-PROP-TO, can be practically utilized to enhance the fracture toughness of the structures during the optimization process by taking critical regions into account as pre-defined cracks. Breaking the non-local interactions (bonds) between relevant PD particles enables us to readily model cracks. Utilizing this advantage, we solve several benchmark optimization problems including different numbers, positions, and alignments of the cracks. The major differences between the proposed methods are examined by comparing optimum topologies for various cracked scenarios. Moreover, the mechanical behaviour of the optimized structures is investigated under dynamic loads to prove the significant improvements achieved by the present approach in the final designs. The results of dynamic analyses reveal the viability of both PD-TO methods for increasing the fracture toughness of the structure in the optimization stage. Overall, the proposed approach is confirmed as a superior design and optimization tool for future engineering structures.Graphical abstract

Three-dimensional Ti3C2 structure design and in-situ growth of nano-TiO2 crystals to realize high performance lithium-sulfur battery

Lithium–sulfur (Li–S) batteries represent a promising energy storage system with the potential to replace traditional lithium-ion batteries. Recent research has explored the practical applications of Li–S batteries. However, due to the insulation properties of the sulfur components and the shuttle effect of polysulfides, the practical application of Li–S batteries is hindered by poor cycle stability and short life. In this study, we developed a controllable three-dimensional Ti3C2 structure design process, and through in situ growth of TiO2 nanocrystals, we prepared three-dimensional porous materials with TiO2@Ti3C2 heterostructures. These materials constructed using two-dimensional lamellar Ti3C2 function as a conductive skeleton to improve the conductivity of the sulfur cathodes, and through the in-situ growth of nano-TiO2 to introduce more binding sites and provide more chemisorption sites to limit the dissolution and shuttle of polysulfides. In addition, the TiO2@Ti3C2 heterointerface generated in situ on the surface of the lamellar structure can induce an internal electric field and increase active reaction sites, which promotes reaction kinetics, accelerates charge diffusion/transport, and promotes LiPS transformation. The materials designed in this study can effectively restrain the shuttle effect by realising the association process of adsorption, capture, and transformation of polysulfides. Thus, when applied as the sulfur cathode frame, it shows a high specific capacity of 1261.41 mAh g−1 at a rate of 0.1 C. In addition, a specific capacity of 66.5 % is maintained over 500 cycles at a rate of 1 C. This strategy supports the development of Li–S batteries with extraordinary performance and opens up a promising way to design next-generation electrochemical energy storage devices.

Host-design strategies of zinc anodes for aqueous zinc-ion batteries.

Aqueous zinc ion batteries (AZIBs) have garnered considerable interest as an eco-friendly, safe, and cost-effective energy storage solution. Although significant strides have been made in recent years, there remain technical hurdles to overcome. Herein, this review summarizes in detail the primary challenges confronting aqueous zinc ion batteries, including the rampant dendrite growth, and water-induced parasitic reactions, and proposes host-engineering modification strategies focusing on optimizing the structure design of the zinc anode substrates, involving three-dimensional structure design, zincophilicity regulation, and epitaxial-oriented modification, and comprehensively analyzes the structure-activity relationship between different modification strategies and battery performance. In addition, we highlight the research trends and prospects in future anode modification for aqueous zinc-ion batteries. This work offers valuable insights into advanced Zn anode constructions for further applications in high-performance AZIBs.

Design, simulation, and measurement of near-zero-index shells for electromagnetic beam generation

We present design and simulation of three-dimensional (3D) shell structures, which generate directional radiation patterns from isotropic sources thanks to their near-zero-index (NZI) characteristics, as well as realizations of these shells via low-cost 3D printing. Throughout the design process of NZI beam generators, both homogenized structures, for which near-zero relative permittivity and/or permeability values are enforced, and actual models involving periodic arrangements of dielectric rods are considered. Solutions of the electromagnetic problems are obtained by using rigorous implementations of the state-of-the-art surface-integral-equation (SIE) formulations in frequency domain. Iterative solutions of matrix equations derived from SIEs are accelerated by different forms of the multilevel fast multipole algorithm (MLFMA) and suitable preconditioners, when necessary. In the design process of NZI shells, alternative strategies are employed to obtain customized radiation patterns. In this context, various cavities with strong resonance behaviors are designed as source regions. At the same time, outer surfaces are modified to either enhance or suppress outgoing electromagnetic fields. In addition to comprehensive simulations and analyses of NZI beam generators, their capabilities are verified by measurements, specifically at 10.3 GHz, on different prototypes fabricated via 3D printing. Measurements of diverse NZI shell structures are presented to demonstrate that NZI properties can successfully be achieved by well-designed arrangements of dielectric rods with proper materials. The results demonstrate the feasibility of efficient, effective, low-cost, and reconfigurable NZI shells to generate alternative beam configurations that can be useful in a plethora of microwave applications.

Kirigami-based inverse design for 3D surfaces formed by mechanically guided method

The mechanically guided assembly method utilizes the compressive buckling behavior of thin-film structures to transform two-dimensional (2D) precursors into three-dimensional (3D) structures. Previous research has shown that by inverse designing thickness and width distributions in 2D precursors, various 3D surfaces with target geometries can be accurately assembled. However, the variation in thickness poses significant challenges for the fabrication of the 2D precursor, especially on a small scale. In this paper, we propose a Kirigami-based inverse design framework that utilizes pre-specified incision patterns as critical parameters to control the bending stiffness distribution of 2D precursors. This enables the fabrication of target 3D structures with constant thickness, which greatly simplifies the production of 2D precursors. By studying the deformation characteristics of beam models during pure bending, we have established an analytical relationship between incision patterns and bending stiffness distribution. To validate the effectiveness of our inverse design theory, we conducted a series of simulations and experiments on 3D structures, yielding favorable comparison results. Moreover, guided by this inverse design theory, we have developed a microneedle structure through conceptual design, demonstrating the capability of Kirigami patterns in the inverse design of complex 3D structures, and highlighting the potential application of our method in the biomedical field.

Multi-objective generative design of three-dimensional material structures

Generative design for materials has recently gained significant attention due to the rapid evolution of generative deep learning models. There have been a few successful generative design demonstrations of molecular-level structures with the help of graph neural networks. However, in the realm of macroscale material structures, most of the works are targeting two-dimensional, ungoverned structure generations. Hindered by the complexity of 3D structures, it is hard to extract customized structures with multiple desired properties from a large, unexplored design space. Here we report a novel framework, a multi-objective driven Wasserstein generative adversarial network (WGAN), to implement inverse designs of 3D structures according to given geometrical, structural, and mechanical requirements. Our framework consists of a WGAN-based network that generates 3D structures possessing geometrical and structural features learned from the target dataset. Besides, multiple objectives are introduced to our framework for the control of mechanical property and isotropy of the structures. An accurate surrogate model is incorporated into the framework to perform efficient prediction on the properties of generated structures in training iterations. With multiple objectives combined by their weight and the 3D WGAN acting as a soft constraint to regulate features that are hard to define by the traditional method, our framework has proven to be capable of tuning the properties of the generated structures in multiple aspects while keeping the selected structural features. The feasibility of a small dataset and the scalability of the objectives of other properties make our work an effective approach to provide fast and automated structure designs for various functional materials.

Confinement Effect and 3D Design Endow Unsaturated Single Ni Atoms with Ultrahigh Stability and Selectivity toward CO2 Electroreduction.

Developing single-atomic catalysts with superior selectivity and outstanding stability for CO2 electroreduction is desperately required but still challenging. Herein, confinement strategy and three-dimensional (3D) nanoporous structure design strategy are combined to construct unsaturated single Ni sites (Ni-N3) stabilized by pyridinic N-rich interconnected carbon nanosheets. The confinement agent chitosan and its strong interaction with g-C3N4 nanosheet are effective for dispersing Ni and restraining their agglomeration during pyrolysis, resulting in ultrastable Ni single-atom catalyst. Due to the confinement effect and structure advantage, such designed catalyst exhibits a nearly 100% selectivity and remarkable stability for CO2 electroreduction to CO, exceeding most reported state-of-the-art catalysts. Specifically, the CO Faradaic efficiency (FECO) maintains above 90% over a broad potential range (-0.55 to -0.95V vs. RHE) and reaches a maximum value of 99.6% at a relatively low potential of -0.67V. More importantly, the FECO is kept above 95% within a long-term 100h electrolyzing. Density functional theory (DFT) calculations explain the high selectivity for CO generation is due to the high energy barrier required for hydrogen evolution on the unsaturated Ni-N3. This work provides a new designing strategy for the construction of ultrastable and highly selective single-atom catalysts for efficient CO2 conversion.

Large interlayer Dzyaloshinskii-Moriya interactions across Ag-layers

Seeking to enhance the strength of the interlayer Dzyaloshinskii-Moriya interaction (IL-DMI) through a combination of atomic and Rashba type spin-orbit coupling (SOC) we studied the strength and the thickness evolution of effective interlayer coupling in Co/Ag/Co trilayers by means of surface sensitive magneto-optical measurements that take advantage of the light penetration depth. Here, we report the observation of oscillatory, thickness-dependent chiral interaction between ferromagnetic layers. Despite the weakness of the Ag atomic SOC, the IL-DMI in our trilayers is orders of magnitude larger than that of known systems using heavy metals as a spacer except of recently reported −0.15 mJ/m2 in Co/Pt/Ru(t)/Pt/Co and varies between ≈ ±0.2 mJ/m2. In contrast to known multilayers Co/Ag/Co promotes in-plane chirality between magnetic layers. The strength of IL-DMI opens up new routes for design of three-dimensional chiral spin structures combining intra- and interlayer DMI and paves the way for enhancements of the DMI strength.

Achieving Fast Oxygen Reduction on Oxide Electrodes by Creating 3D Multiscale Micro-Nano Structures for Low-Temperature Solid Oxide Fuel Cells.

Fast oxygen reduction reaction (ORR) at the cathode is a key requirement for the realization of low-temperature solid oxide fuel cells (SOFCs). While the design of three-dimensional (3D) structures has emerged as a new and promising approach to improving the electrochemical performance of SOFC cathodes, achieving versatile structures and structural stability is still challenging. In this study, we demonstrate a novel architectural design for a superior cathode with fast ORR activity. By employing a completely new fabrication process comprising a 3D printing technique and pulsed laser deposition (PLD), we design 3D La0.8Sr0.2CoO3-δ (LSC) micro-nano structures with the desired shape. 3D-printed yttria-stabilized ZrO2 (YSZ) microstructures significantly increase the ratio of surface area to volume while maintaining suitable ionic conductivity comparable to that of single-crystalline YSZ substrates. Scanning electron microscopy and energy dispersive X-ray microanalysis reveal the formation of crack- or void-free YSZ microstructures and the uniform deposition of LSC films by PLD on the YSZ microstructures. The 3D LSC micro-nano structures show significantly enhanced oxygen surface exchange coefficients (kchem) extracted from electrical conductivity relaxation (ECR) measurements by up to 3 orders of magnitude relative to the bulk LSC. Furthermore, electrochemical impedance spectroscopy measurements verify the kchem values from ECR and no directional difference in the measured ORR activity depending on the shape of 3D microstructures. The dramatic enhancement of the ORR activity of LSC is attributed to the increased film surface areas resulting from the 3D YSZ microstructures.

Bimetallic nanocubes embedded in biomass-derived porous carbon to construct magnetic/carbon dual-mechanism layered structures for efficient microwave absorption

Biomass-derived porous carbon materials have great potential for the development of lightweight and efficient broadband microwave absorbers. In this study, we reported the successful immobilization of Co3O4/CoFe2O4 nanocubes on porous carbon derived from ginkgo biloba shells by activated carbonization and electrostatic self-assembly processes. The optimal reflection loss value of the prepared BPC@Co3O4/CoFe2O4 reaches −68.5 dB when the filling load is 10 wt%, and the effective absorption bandwidth is 6.2 GHz with a matching thickness of 2 mm. The excellent microwave absorption (MA) performance is attributed to the rational three-dimensional structural design, the modulation of magnetic/carbon components, the optimized impedance matching, and the coordinated action of multiple mechanisms. It was further demonstrated by high-frequency structural simulation that the composite can effectively dissipate microwave energy in practical applications. Therefore, the results indicate a favorable potential of the synthesis and application of semiconductor/magnetic component/biomass-derived carbon microwave absorbing materials.