Ideal 3D Research Articles

Anomalous Superconducting Proximity Effect in Bi2 Se3 /FeSe0.5 Te0.5 Thin-Film Heterojunctions.

The superconducting proximity effect (SPE) induces a superconductivity transition in otherwise non-superconducting thin films in proximity with a superconductor. The SPE usually occurs in real space and decays exponentially with film thickness. Herein, an abnormal SPE in a topological insulator (TI)/superconductor heterostructure is unveiled, which is attributed to the topologically protected surface state. Surprisingly, such abnormal SPE occurs in momentum space regardless of the TI film thickness, as long as the topological surface states are robust and form a continuous conduction loop. Combining transport measurements and scanning tunneling microscopy/spectroscopy techniques, the SPE in Bi2 Se3 /FeSe0.5 Te0.5 heterostructures is explored, where Bi2 Se3 is an ideal 3D topological insulator and FeSe0.5 Te0.5 a typical iron-based superconductor. As the thickness of the Bi2 Se3 thin film exceeds 400 nm, there still exists SPE-induced superconductivity on the surface of Bi2 Se3 thin film with a transition temperature Tc not less than 10 K. Such an extraordinary behavior is induced by the unique properties of topologically protected surface states of Bi2 Se3 . This research deepens the understanding of the important role of topologically protected surface states in the SPE.

AN ALTERNATIVE 3D ADDRESS VISUALIZATION METHOD FOR BUILDINGS AND BUILDING INDEPENDENT SECTIONS WITH GIS-BASED 3D MODELLING APPROACH

Abstract. Most commonly used detail type in 3D city modelling is building layer. One of the most important distinguishing point of buildings is independent sections. When the independent sections are examined in the context of Urban Information System (UIS), they have a multi-layered structure with their own characteristics. In address management processes, definition of the area belonging to a person, family or organization is realized through independent sections of buildings. In this study, it is aimed to model one the most important components of city objects such as building independent sections and road networks with GIS-based 3D modelling techniques. According to the results obtained from literature studies, answers were researched to the questions of what should be workflow of producing 3D models in the system and what should be in ideal 3D GIS database. Buildings and building independent sections were geocoded to provide some additional innovations to address mapping methods. Procedural modelling method was preferred as a GIS-based 3D modelling technique. Created models enable both the visualization of address data and their transfer to the 3D environment, as well as navigation. It provides some practical information. The designed system has been tested practically in Trabzon city.

Monolayer RhB4 : Half-auxeticity and almost ideal spin-orbit Dirac point semimetal

Structural-property relationship, the connection between materials' structures and their properties, is central to the materials research. Especially at reduced dimensions, novel structural motifs often generate unique physical properties. Motivated by a recent work reporting a novel half-auxetic effect in monolayer ${\mathrm{PdB}}_{4}$ with a hypercoordinated structure, here we extensively explore similar two-dimensional (2D) transition-metal boride structures $M{\mathrm{B}}_{4}$ with $M$ covering $3d$ and $4d$ elements. Our investigation screens out one stable candidate, the monolayer ${\mathrm{RhB}}_{4}$. We find that monolayer ${\mathrm{RhB}}_{4}$ also shows half-auxeticity, i.e., the material always expands in a lateral in-plane direction in response to an applied strain in the other direction, regardless of whether the strain is positive or negative. We show that this special mechanical character is intimately tied to the hypercoordinated structure with the $MC\text{\textcopyright{}}{\mathrm{B}}_{8}$ structural motif. Furthermore, regarding electronic properties, monolayer ${\mathrm{RhB}}_{4}$ is found to be an example of an almost ideal 2D spin-orbit Dirac-point semimetal. The low-energy band structure is clean, with a pair of fourfold degenerate Dirac points robust under spin-orbit coupling located close to the Fermi level. These Dirac points are $enforced$ by the nonsymmorphic space-group symmetry which is also determined by the lattice structure. Our work deepens the fundamental understanding of structural-property relationship in reduced dimensions. The half-auxeticity and the spin-orbit Dirac points will make monolayer ${\mathrm{RhB}}_{4}$ a promising platform for nanomechanics and nanoelectronics applications.

Application of Computer-Aided Design and Individualized Templates for Bilateral Zygomaticomaxillary Complex Fractures.

Reduction of the bilateral zygomaticomaxillary complex (ZMC) fracture with individualized templates based on computer- aided surgical simulation system. To evaluate the practicality and accuracy of this approach in the treatment of bilateral ZMC fracture. Sixteen patients with bilateral ZMC fractures were collected to create a study model. The authors reconstruct the ZMC on one side via the three-dimensional (3D) model, and then mirrored to the opposite side. Multiple individualized templates were made based on the 3D model, and used as intraoperative guidance to reduce fractures. After surgery, the facial symmetry and the position of zygoma were observed. The mouth opening, pupil level, and sensation of infraorbital nerve were evaluated. Some mark points on zygoma were measured and the postoperative horizontal asymmetry rate (H) was calculated. Besides, orbital height and width were measured. For all patients, the position of bilateral ZMC was basically restored. The patients with restriction of mouth opening all recovered to normal. The H values were less than 3.0% at all mark points. There was almost no difference in bilateral orbital width and height. Meanwhile, there was no significant difference between the preoperative measurements of the ideal virtual 3D model and the postoperative measurements of patients. The study proves that application of computer-aided design and individualized templates can accurately guide the reduction operation of ZMC fracture, restore the ideal shape of ZMC, and obtain good facial symmetry.

3D Cell Culture Systems: Tumor Application, Advantages, and Disadvantages.

The traditional two-dimensional (2D) in vitro cell culture system (on a flat support) has long been used in cancer research. However, this system cannot be fully translated into clinical trials to ideally represent physiological conditions. This culture cannot mimic the natural tumor microenvironment due to the lack of cellular communication (cell-cell) and interaction (cell-cell and cell-matrix). To overcome these limitations, three-dimensional (3D) culture systems are increasingly developed in research and have become essential for tumor research, tissue engineering, and basic biology research. 3D culture has received much attention in the field of biomedicine due to its ability to mimic tissue structure and function. The 3D matrix presents a highly dynamic framework where its components are deposited, degraded, or modified to delineate functions and provide a platform where cells attach to perform their specific functions, including adhesion, proliferation, communication, and apoptosis. So far, various types of models belong to this culture: either the culture based on natural or synthetic adherent matrices used to design 3D scaffolds as biomaterials to form a 3D matrix or based on non-adherent and/or matrix-free matrices to form the spheroids. In this review, we first summarize a comparison between 2D and 3D cultures. Then, we focus on the different components of the natural extracellular matrix that can be used as supports in 3D culture. Then we detail different types of natural supports such as matrigel, hydrogels, hard supports, and different synthetic strategies of 3D matrices such as lyophilization, electrospiding, stereolithography, microfluid by citing the advantages and disadvantages of each of them. Finally, we summarize the different methods of generating normal and tumor spheroids, citing their respective advantages and disadvantages in order to obtain an ideal 3D model (matrix) that retains the following characteristics: better biocompatibility, good mechanical properties corresponding to the tumor tissue, degradability, controllable microstructure and chemical components like the tumor tissue, favorable nutrient exchange and easy separation of the cells from the matrix.

Atomically Thin Materials for Next-Generation Rechargeable Batteries.

Atomically thin materials (ATMs) with thicknesses in the atomic scale (typically <5 nm) offer inherent advantages of large specific surface areas, proper crystal lattice distortion, abundant surface dangling bonds, and strong in-plane chemical bonds, making them ideal 2D platforms to construct high-performance electrode materials for rechargeable metal-ion batteries, metal-sulfur batteries, and metal-air batteries. This work reviews the synthesis and electronic property tuning of state-of-the-art ATMs, including graphene and graphene derivatives (GE/GO/rGO), graphitic carbon nitride (g-C3N4), phosphorene, covalent organic frameworks (COFs), layered transition metal dichalcogenides (TMDs), transition metal carbides, carbonitrides, and nitrides (MXenes), transition metal oxides (TMOs), and metal-organic frameworks (MOFs) for constructing next-generation high-energy-density and high-power-density rechargeable batteries to meet the needs of the rapid developments in portable electronics, electric vehicles, and smart electricity grids. We also present our viewpoints on future challenges and opportunities of constructing efficient ATMs for next-generation rechargeable batteries.

2D RF pulse design for optimized reduced field-of-view imaging at 1.5T and 3T

Two-dimensional spatially selective radiofrequency (2DRF) excitation pulses are widely used for reduced field-of-view (FOV) targeted high-resolution diffusion weighted imaging (DWI), especially for anatomically small regions such as the spinal cord and prostate. The reduction in FOV achieved by 2DRF pulses significantly improve the in-plane off-resonance artifacts in single-shot echo planar imaging (ss-EPI). However, long durations of 2DRF pulses create a sensitivity to through-plane off-resonance effects, especially at 3T where the off-resonance field doubles with respect to 1.5T. This work proposes a parameter-based optimization approach to design 2DRF pulses with blips along the slice-select axis, with the goal of maximizing slab sharpness while minimizing off-resonance effects on 1.5T and 3T MRI scanners, separately. Extensive Bloch simulations are performed to evaluate the off-resonance robustness of 2DRF pulses. Three different metrics are proposed to quantify the similarity between the actual and ideal 2D excitation profiles, based on the signals within and outside the targeted reduced-FOV region. In addition, simulations on a digital brain phantom are performed for visual comparison purposes. The results show that maintaining a sharp profile is the primary design requirement at 1.5T, necessitating the usage of relatively high slab sharpness with a time-bandwidth product (TBW) around 8–10. In contrast, off-resonance robustness is the primary design requirement at 3T, requiring the usage of a moderate slap sharpness with TBW around 5–7.

Promising Properties of a Sub-5-nm Monolayer MoSi2N4 Transistor

Two-dimensional (2D) semiconductors have attracted tremendous interests as natural passivation and atomically thin channels that could facilitate continued transistor scaling. However, air-stable 2D semiconductors with high performance were quite elusive. Recently, extremely air-stable MoSi2N4 monolayer had been successfully fabricated [Hong et al., Science 369, 670 (2020)]. To further reveal its potential applications in the sub-5 nm MOSFETs, there is an urgent need to develop integrated circuits. Here we report first-principles quantum transport simulations on the performance limits of n- and p-type sub-5 nm monolayer (ML) MoSi2N4 metal-oxide-semiconductor FETs (MOSFETs). We find that the on-state current in the MoSi2N4 MOSFETs can be effectively manipulated by the length of gate and underlap (UL), as well as the doping concentration. Very strikingly, we also find that the n-type devices the optimized on-state current can reach up to 1390 and 1025 uA/um for the high performance (HP) and low power (LP) applications, respectively, both of which satisfy the International Technology Roadmap for Semiconductors (ITRS) requirements. Whereas, the optimized on-state current can meet the LP application (348 uA/um) for the p-type devices. Finally, we find that the MoSi2N4 MOSFETs have ultra-low subthreshold swing and power delay product, which have potential to realize the high speed and low power consumption devices. Our results show that MoSi2N4 is an ideal 2D channel material for future competitive ultrascaled devices.

Human interventions in a bifurcating river system: Numerical investigation and uncertainty assessment

AbstractIn bifurcating rivers, an intervention aimed at flood risk reduction may trigger a change in discharge distribution and thus influence water levels throughout the entire river system. This article aims at assessing the impact of interventions on system‐wide water levels, explicitly accounting for a range of discharges and model parameter uncertainty. An idealized 1D model with dimensions of the bifurcating Dutch Rhine River is used. The results show that an unwanted increase in water levels downstream of the intervention occurs due to an increased discharge if a single intervention is implemented in a distributary. This effect can be counteracted by implementing a second intervention that balances the hydraulic effect of the first intervention at the bifurcation. However, unwanted water level increases still occur at other discharges. Furthermore, while interventions may reduce local water‐level‐uncertainty, it appears that uncertainty in discharge distribution is not reduced. This implies that flooding probabilities cannot be reduced throughout the entire river system by the implementation of interventions in upstream reaches. Concluding, for intervention design in a bifurcating river, it is important to consider the entire river system and explicitly account for a range of discharge conditions to avoid unwanted water level increases throughout the river system.

Alginate-gelatin based core-shell capsule enhances the osteogenic potential of human osteoblast-like MG-63 cells

Three-dimensional (3D) cell culture enhanced cells-cells communication, promoting developmental processes and influencing cell performance. In this study, 3D alginate-gelatin core–shell capsules (AGC) were fabricated by using a microfluidic device. Human osteoblast-like MG-63 cells were encapsulated within the 3D model. The morphology and physicochemical properties of the AGC were characterized by using scanning electron microscopy (SEM), Flourier Transform Infrared Spectrum (FTIR), Gravimetric thermal analyzer (TGA). The mRNA levels of osteogenetic gene markers were measured by quantitative real-time RT-PCR. The result of a 9.6% weight loss after a 7-day soaking indicates that the AGC exhibited excellent stability. The encapsulated MG-63 cells formed clusters alongside the core of AGC and obtained 200% cell viability after 21-day long-term cultivation. Compared to traditional 2D cell culture, the 3D cultured MG-63 cells performed higher alkaline phosphatase(ALP), a 9.3-fold increase of calcium mineralization activity, and enhanced osteogenic gene expression of BGLAP, COL1A1, and Runx2. These observations suggested that AGC obtains the potential as an ideal 3D microenvironmental cell culture system for biomedical application.

Manipulation of Dirac Fermions in Nanochain-Structured GrapheneSupported by the National Key Research and Development Program of China (Grant Nos. 2020YFA0308800 and 2016YFA0202300), the National Natural Science Foundation of China (Grant Nos. 11974045 and 61888102), Chinese Academy of Sciences (Grant No. XDB30000000), Beijing Institute of Technology Research Fund Program for Young Scholars (Grant No. 3050011181909), and China Postdoctoral Science Foundation (Grant

Graphene has afforded an ideal 2D platform for investigating a rich and fascinating behavior of Dirac fermions. Here, we develop a theoretical mechanism for manipulating the Dirac fermions in graphene, such as from type-I to type-II and type-III, by a top-down nanopatterning approach. We demonstrate that by selective chemical adsorption to pattern the 2D graphene into coupled 1D armchair chains (ACs), the intrinsic isotropic upright Dirac cone becomes anisotropic and strongly tilted. Based on model analyses and first-principles calculations, we show that both the shape and tilt of Dirac cone can be tuned by the species of chemisorption, e.g., halogen vs hydrogen, which modifies the strength of inter-AC coupling. Furthermore, the topological edge states and transport properties of the engineered Dirac fermions are investigated. Our work sheds lights on understanding the Dirac fermions in a nanopatterned graphene platform, and provides guidance for designing nanostructures with novel functionality.

TLS-FEM INTEGRATED STRUCTURAL DEFORMATION ANALYSIS ON THE BEAMLESS HALL AT NANJING, CHINA

Abstract. A method integrating terrestrial laser scanning (TLS) and finite element modelling (FEM) is proposed in this study. It aims at assessing the structural deformation of a historic brick-masonry building, the Beamless Hall at Linggu Temple in Nanjing, China. The building was composed of a series of vaults and arches, the largest among whom spans over 11m. TLS (Z+F Imager5010X) was used to collect 3D point cloud with high density. Point slices and geometric feature computation (verticality) were employed to detect geometric displacement quantitatively and intuitively. FEM-simulation was based on an ideal 3D model ignoring geometric anomalies. Results show that the Beamless Hall has inherent structural defect owing to its asymmetric layout along the transverse axis. Computing geometric feature of point cloud is fast and intuitive to detect and show geometric deviation. Inferred by FEM-simulated results and TLS-based deviation analysis, the building’s asymmetrical layout under self-weight is probably the main reason causing its structural deformation. Further developments include FEM based on as-built geometry, corrected materials parameters, and a comprehensive geometric deviation analysis.

Large field-of-view holographic display by gapless splicing of multisegment cylindrical holograms.

A holographic three-dimensional (3D) display is a recognized and ideal 3D display technology. In the field of holographic research, cylindrical holography with the merit of 360° field of view (FOV) has recently become a hot issue, as it naturally solves the problem of limited FOV in planar holography. The recently proposed approximate phase compensation (APC) method successfully obtains larger FOV and fast generation of segment cylindrical hologram (SCH) in the visible light band. However, the FOV of SCH remains limited due to its intrinsic limitations, and, to our best knowledge, the issue has not been effectively addressed. In this paper, the restricted conditions are first analyzed for the generation of SCH by the APC method. Then, an FOV expansion method is proposed for realizing a large FOV holographic display by gapless splicing of multi-SCH. The proposed method can successfully obtain larger FOV cylindrical holograms and effectively eliminate the splicing gaps; its effectiveness is verified by the results of numerical simulation and optical experiments. Therefore, the proposed method can effectively solve the FOV limitation problem of the APC method for the generation of SCH in the visible band, realize a large FOV 3D display, and provide a useful reference for holographic 3D display.

Epitaxial Growth of Quasi-One-Dimensional Bismuth-Halide Chains with Atomically Sharp Topological Non-Trivial Edge States.

Quantum spin Hall insulators (QSHIs) have one-dimensional (1D) spin-momentum locked topological edge states (ES) inside the bulk band gap, which can serve as dissipationless channels for the practical applications in low consumption electronics and high performance spintronics. However, obtaining the clean and atomically sharp ES which serves as ideal 1D spin-polarized nondissipative conducting channels is demanding and still a challenge. Here, we report the formation of the quasi-1D Bi4I4 nanoribbons on the surface of Bi(111) with the support of the graphene-terminated 6H-SiC(0001) and the direct observation of the topological ES at the step edges by the scanning tunneling microscopy (STM) and spectroscopic-imaging results. The ES reside surround the edge of Bi4I4 nanoribbons and exhibits noteworthy robustness against nontime reversal symmetry (non-TRS) perturbations. The theoretical simulations verify the topological nontriviality of 1D ES, which is retained after considering the presence of the underlying Bi(111). Our study supports the existence of topological ES in Bi4I4 nanoribbons, benefiting to engineer the topological features by using the 1D nanoribbons as building blocks.

Graphene-mediated ferromagnetic coupling in the nickel nano-islands/graphene hybrid

Nanoscale magnetic structures are fundamental to the design and fabrication of spintronic devices and have exhibited tremendous potential superior to the conventional semiconductor devices. However, most of the magnetic moments in nanostructures are unstable due to size effect, and the possible solution based on exchange coupling between nanomagnetism is still not clear. Here, graphene-mediated exchange coupling between nanomagnets is demonstrated by depositing discrete superparamagnetic Ni nano-islands on single-crystal graphene. The heterostructure exhibits ideal two-dimensional (2D) ferromagnetism with clear hysteresis loops and Curie temperature up to 80 K. The intrinsic ferromagnetism in graphene and antiferromagnetic exchange coupling between graphene and Ni nano-islands are revealed by x-ray magnetic circular dichroism and density functional theory calculations. The artificial 2D ferromagnets constitute a platform to study the coupling mechanism between complex correlated electronic systems and magnetism on the nanoscale, and the results and concept provide insights into the realization of spin manipulation in quantum computing.

Numerical simulation of impact sound transmission control across a smart hybrid double floor system equipped with a genetically-optimized NES absorber

An idealized detailed 2D formulation is presented for suppression of transient impact sound transmission across a hybrid smart double-leaf sandwich beam (floor-ceiling) structure into a rectangular (receiving) room with ideally flat and rigid walls. The smart double wall structure, which is mechanically inter-connected at an arbitrary point with a lightweight nonlinear energy sink (NES) absorber, incorporates spatially distributed and electrically independent non-collocated semiactive (electro-rheological fluid- or ERF-incorporated) and fully-active (piezoceramic- or PZT-incorporated) actuator layers functioning in a closed loop control framework. Extensive time-domain numerical simulations initially calculate both the uncontrolled and controlled transient acoustic pressure fields in absence of the dynamic vibration absorber for four separate settings of the active (PZT-) and semiactive (ERF-) actuation elements. Subsequently, the remarkable performance of the GA-optimized hybrid smart active/semi-active/passive (PZT/ERF/NES) configuration, which benefits from the multi-mode targeted energy transfer (TET) mechanism of the NES, in significant broadband (low frequency) attenuation of the transmitted shock energy with a much lower actuator energy demand, is demonstrated. Furthermore, some important aspects of the transient fluid-structure interaction (TFSI) control problem like weakening of the acoustic shock focusing effects (focal zones) within the source room are illustrated through selected early-to-late-times 2D images and animations of the cavity pressure fields. Limiting situations are studied and correctness of the derivations is established against accessible data in addition to numerical (FEM) simulations.

Experimental investigation of damaged RC joints retrofitted by stiffened angles and bars

Experimental studies reveal that weakness in joint core leads to the formation of a shear hinge in this area, loss of load carrying capacity in the both regions of cyclic curve and decrease of ductility. Generally, the recent mentioned results are related to the previous studies, in which the effect of slabs and lateral beams (2D joints) have been neglected. However, these effects can lead to different responses in real joints compared to ideal 2D joints, in the term of changes in capacity and demand. Consequently, in this study the effect of slab and lateral beam has been considered (3D joints). Four 3D external joints with a scale of 1/2 are made in the laboratory. Specimens include two control joints and two damaged joints retrofitted by stiffened angles and post-tensioned bars. The results show that the use of retrofit method for damaged joints results in the formation of a flexural plastic hinge in the beam and shift of the shear hinge out of the joint core. Furthermore, the effect of slab and lateral beam in the bare non-seismic joint may lead to the increase of the ductility, compared to the similar 2D joints in previous studies.

Remote 3D face reconstruction by means of autonomous unmanned aerial vehicles

The 3D face model of an individual includes a rich amount of information useful in many application scenarios. Currently, the 3D reconstruction from images is obtained through multiple acquisitions at different distances and angles in a controlled environment. “In the wild’ conditions, or inadequate acquisition systems, can make 3D reconstruction a strongly error-prone problem. This paper illustrates a system that creates 3D face models from images taken by unmanned aerial vehicles in a completely automatic way. The proposed method is adaptive, dynamic, and contactless. No human intervention is required for image acquisition. Experimental results are described—in particular, the comparison between the ideal 3D reconstructions, obtained in controlled and cooperative conditions, and the reconstructions obtained by the drone during flight at different resolutions. The results show good overlap of the models and a low co-registration error. Given the free mobility of the UAVs, the system is suitable, among other applications, for biometrics and open-air access control over large areas.

Terrace-confined guided growth of high-density ultrathin silicon nanowire array for large area electronics

Ultrathin silicon nanowires (SiNWs) are ideal 1D channels to construct high performance nanoelectronics and sensors. We here report on a high-density catalytic growth of orderly ultrathin SiNWs, with diameter down to and narrow NW-to-NW spacing of only ∼80 nm, without the use of high-resolution lithography. This has been accomplished via a terrace-confined strategy, where tiny indium (In) droplets move on sidewall terraces to absorb precoated amorphous Si layer as precursor and produce self-aligned SiNW array. It is found that, under proper parameter control, a tighter terrace-step confinement can help to scale the dimensions of the SiNW array down to the extremes that have not been reported before, while maintaining still a stable guiding growth over complex contours. Prototype SiNW field effect transistors demonstrate a high I on/I off current ratio ∼107, low leakage current of ∼0.3 pA and steep subthreshold swing of 220 mV dec−1. These results highlight the unexplored potential of catalytic growth in advanced nanostructure fabrication that is highly relevant for scalable SiNW logic and sensor applications.

Predicting an ideal 2D carbon nanostructure with negative Poisson's ratio from first principles: implications for nanomechanical devices

The intrinsic negative Poisson’s ratio effect at the level of molecule in two-dimensional nanomaterials, especially in the perfect planar nanostructures with a single atom thickness, is really rare and has attracted a lot of research interests because of its unique mechanical properties in the nanoscale and extensive applications in mechanical nanodevices. In this work, a novel ideal planar carbon nanostructure (PCNS) framework with a single atom thickness composed by carbon and hydrogen atoms is proposed and studied by means of first-principles density functional calculation. The results showed that the PCNS is, simultaneously, of excellent thermodynamic, molecular dynamic and mechanical stabilities. In addition, the electronic structure, mechanical characters, and optical-electronic characteristics of PCNS are also explored. Excitedly, it is found that the PCNS has a significant negative Poisson's ratio effect in plane, and the maximum value of Poisson's ratio is as high as − 2.094. Meanwhile, the material has a wide range of elastic mechanics. Moreover, the PCNS presents an ideal UV absorption performance. It is hoped that this work could be a useful structural design strategy for the development of the ideal 2D carbon-based nanomechanical devices with the intrinsic negative Poisson’s ratio effect and other electronic functions. An ideal 2D carbon nanostructure with negative Poisson's ratio was designed and its properties were investigated from first principles calculation.