Now showing items 21-40 of 50282

    • Application of phase-field method in rechargeable batteries

      Wang, Qiao; Zhang, Geng; Li, Yajie; Hong, Zijian; Wang, Da; Shi, Siqi (npj Computational Materials, Springer Science and Business Media LLC, 2020-11-19) [Article]
      AbstractRechargeable batteries have a profound impact on our daily life so that it is urgent to capture the physical and chemical fundamentals affecting the operation and lifetime. The phase-field method is a powerful computational approach to describe and predict the evolution of mesoscale microstructures, which can help to understand the dynamic behavior of the material systems. In this review, we briefly introduce the theoretical framework of the phase-field model and its application in electrochemical systems, summarize the existing phase-field simulations in rechargeable batteries, and provide improvement, development, and problems to be considered of the future phase-field simulation in rechargeable batteries.
    • Developing the Raster Big Data Benchmark: A Comparison of Raster Analysis on Big Data Platforms

      Haynes, David; Mitchell, Philip M.; Shook, Eric (ISPRS International Journal of Geo-Information, MDPI AG, 2020-11-19) [Article]
      Technologies around the world produce and interact with geospatial data instantaneously, from mobile web applications to satellite imagery that is collected and processed across the globe daily. Big raster data allow researchers to integrate and uncover new knowledge about geospatial patterns and processes. However, we are at a critical moment, as we have an ever-growing number of big data platforms that are being co-opted to support spatial analysis. A gap in the literature is the lack of a robust assessment comparing the efficiency of raster data analysis on big data platforms. This research begins to address this issue by establishing a raster data benchmark that employs freely accessible datasets to provide a comprehensive performance evaluation and comparison of raster operations on big data platforms. The benchmark is critical for evaluating the performance of spatial operations on big data platforms. The benchmarking datasets and operations are applied to three big data platforms. We report computing times and performance bottlenecks so that GIScientists can make informed choices regarding the performance of each platform. Each platform is evaluated for five raster operations: pixel count, reclassification, raster add, focal averaging, and zonal statistics using three raster different datasets.
    • Gas-Phase Thermochemistry of MX3 and M2X6 (M = Sc, Y; X = F, Cl, Br, I) from a Composite Reaction-Based Approach: Homolytic versus Heterolytic Cleavage

      Minenkova, Irina; Osina, Evgeniya L.; Cavallo, Luigi; Minenkov, Yury (Inorganic Chemistry, American Chemical Society (ACS), 2020-11-19) [Article]
      A domain-based local-pair natural-orbital coupled-cluster approach with single, double, and improved linear-scaling perturbative triple correction via an iterative algorithm, DLPNO-CCSD(T1), was applied within the framework of the Feller-Peterson-Dixon approach to derive gas-phase heats of formation of scandium and yttrium trihalides and their dimers via a set of homolytic and heterolytic dissociation reactions. All predicted heats of formation moderately depend on the reaction type with the most and least negative values obtained for homolytic and heterolytic dissociation, respectively. The basis set size dependence, as well as the influence of static correlation effects not covered by the standard (DLPNO-)CCSD(T) approach, suggests that exploitation of the heterolytic dissociation reactions with the formation of M3+ and X- ions leads to the most robust heats of formation. The gas-phase formation enthalpies ΔHf°(0 K)/ΔHf°(298.15 K) and absolute entropies S°(298.15 K) were obtained for the first time for the Sc2F6, Sc2Br6, and Sc2I6 species. For ScBr3, ScI3, Sc2Cl6, and Y2Cl6, we suggest a reexamination of the experimental heats of formation available in the literature. For other compounds, the predicted values were found to be in good agreement with the experimental estimates. Extracted MX3 (M = Sc, Y; X = F, Cl, Br, and I) 0 K atomization enthalpies indicate weaker bonding when moving from fluorine to iodine and from yttrium to scandium. Likewise, the stability of yttrium trihalide dimers degrades when going from fluorine to iodine. Respective scandium trihalide dimers are less stable, with 0 K dimer dissociation energy decreasing in the row fluorine - chlorine - bromine ≈ iodine. Correlation of the (n - 1)s2p6 electrons on bromine and iodine, inclusion of zero-point energy, relativistic effects, and the effective-core-potential correction as well as amelioration of the DLPNO localization inaccuracy are shown to be of similar magnitude, which is critical if accurate heats of formation are a goal.
    • Introducing a Cantellation Strategy for the Design of Mesoporous Zeolite-like Metal–Organic Frameworks: Zr-sod-ZMOFs as a Case Study

      Alsadun, Norah Sadun; Mouchaham, Georges; Guillerm, Vincent; Czaban-Jozwiak, Justyna; Shkurenko, Aleksander; Jiang, Hao; Bhatt, Prashant; Parvatkar, Prakash Tukaram; Eddaoudi, Mohamed (Journal of the American Chemical Society, American Chemical Society (ACS), 2020-11-19) [Article]
      Herein we report novel mesoporous zirconium-based metal-organic frameworks (MOFs) with zeolitic sodalite (sod) topology. Zr-sod-ZMOF-1 and -2 are constructed based on a novel cantellation design strategy. Distinctly, organic linkers are judiciously designed in order to promote the deployment of the 12-coordinated Zr hexanuclear molecular building block (MBB) as a tetrahedral secondary building unit, a prerequisite for zeolite-like nets. The resultant Zr-sod-ZMOFs exhibit mesopores with a diameter up to ≈43 Å, while the pore volume of 1.98 cm3·g-1 measured for Zr-sod-ZMOF-1 is the highest reported experimental value for zeolite-like MOFs based on MBBs as tetrahedral nodes.
    • Elucidating the Promotional Effect of Cerium in the Dry Reforming of Methane

      Rodriguez Gomez, Alberto; Lopez-Martin, Angeles; Ramirez, Adrian; Gascon, Jorge; Caballero, Alfonso (ChemCatChem, Wiley, 2020-11-19) [Article]
      A series of Ni-Ce catalysts supported on SBA-15 has been prepared by co-impregnation, extensively characterized and evaluated in the carbon dioxide reforming of methane (DRM). The characterization by TEM, XRD and TPR has allowed us to determine the effect of metal loading on metal dispersion. Cerium was found to improve nickel location inside the mesopores of SBA-15 and to suppress coke formation during the DRM reaction. The analysis by XPS allowed us to associate the high cerium dispersion with the presence of low-coordinated Ce 3+ sites, being main responsible for its promotional effect. A combination of XAS and XPS has permitted us to determine the physicochemical properties of metals under reduction conditions. The low nickel coordination number determined by XAS in Ni-Ce doped systems after reduction suggests the generation of very small nickel particles which showed greater catalytic activity and stability in the reaction, and a remarkable resistance to coke formation.
    • VLG-Net: Video-Language Graph Matching Network for Video Grounding

      Qu, Sisi; Soldan, Mattia; Xu, Mengmeng; Tegner, Jesper; Ghanem, Bernard (arXiv, 2020-11-19) [Preprint]
      Grounding language queries in videos aims at identifying the time interval (or moment) semantically relevant to a language query. The solution to this challenging task demands the understanding of videos' and queries' semantic content and the fine-grained reasoning about their multi-modal interactions. Our key idea is to recast this challenge into an algorithmic graph matching problem. Fueled by recent advances in Graph Neural Networks, we propose to leverage Graph Convolutional Networks to model video and textual information as well as their semantic alignment. To enable the mutual exchange of information across the domains, we design a novel Video-Language Graph Matching Network (VLG-Net) to match video and query graphs. Core ingredients include representation graphs, built on top of video snippets and query tokens separately, which are used for modeling the intra-modality relationships. A Graph Matching layer is adopted for cross-modal context modeling and multi-modal fusion. Finally, moment candidates are created using masked moment attention pooling by fusing the moment's enriched snippet features. We demonstrate superior performance over state-of-the-art grounding methods on three widely used datasets for temporal localization of moments in videos with natural language queries: ActivityNet-Captions, TACoS, and DiDeMo.
    • Hollow Fibers with Encapsulated Green Amino Acid-Based Ionic Liquids for Dehydration

      Gebreyohannes, Abaynesh Yihdego; Upadhyaya, Lakshmeesha; Silva, Liliana P.; Falca, Gheorghe; Carvalho, Pedro J.; Nunes, Suzana Pereira (ACS Sustainable Chemistry & Engineering, American Chemical Society (ACS), 2020-11-18) [Article]
      Dehydration technologies with low energy consumption using non-toxic materials are important in industrial, residential, and transport applications. Herein, nanocomposite polymeric hollow fibers with high dehydration capability were demonstrated with the incorporation of green amino acid-based ionic liquids. The ionic liquid was encapsulated in designed submicrometer carbon capsules (ENILs) and dispersed in thin polydimethylsiloxane (PDMS) coating layers. The effect of different coating compositions and operation conditions on the water vapor permeance and selectivity of water vapor over nitrogen was investigated using vacuum and sweep gas. Both sorption and permeation results suggested strong interactions between the water vapor and the encapsulated ionic liquid. The selectivity greatly depends on the PDMS coating and the amount of loaded ENIL. A linear increase of the water vapor over nitrogen selectivity was observed up to 50% ENIL loading in PDMS. The membrane systems had water vapor permeance up to 10,600 GPU and selectivity of 4500, which are promising characteristics for application in membrane air dehumidification and other dehydration processes
    • Molecularly-porous ultrathin membranes for highly selective organic solvent nanofiltration

      Huang, Tiefan; Moosa, Basem; HOANG, PHUONG; Liu, Jiangtao; Chisca, Stefan; Zhang, Gengwu; Alyami, Mram Z.; Khashab, Niveen M.; Nunes, Suzana Pereira (Nature Communications, Springer Science and Business Media LLC, 2020-11-18) [Article]
      AbstractEngineering membranes for molecular separation in organic solvents is still a big challenge. When the selectivity increases, the permeability tends to drastically decrease, increasing the energy demands for the separation process. Ideally, organic solvent nanofiltration membranes should be thin to enhance the permeant transport, have a well-tailored nanoporosity and high stability in harsh solvents. Here, we introduce a trianglamine macrocycle as a molecular building block for cross-linked membranes, prepared by facile interfacial polymerization, for high-performance selective separations. The membranes were prepared via a two-in-one strategy, enabled by the amine macrocycle, by simultaneously reducing the thickness of the thin-film layers (<10 nm) and introducing permanent intrinsic porosity within the membrane (6.3 Å). This translates into a superior separation performance for nanofiltration operation, both in polar and apolar solvents. The hyper-cross-linked network significantly improved the stability in various organic solvents, while the amine host macrocycle provided specific size and charge molecular recognition for selective guest molecules separation. By employing easily customized molecular hosts in ultrathin membranes, we can significantly tailor the selectivity on-demand without compromising the overall permeability of the system.
    • DeepPheno: Predicting single gene loss-of-function phenotypes using an ontology-aware hierarchical classifier

      Kulmanov, Maxat; Hoehndorf, Robert (PLOS Computational Biology, Public Library of Science (PLoS), 2020-11-18) [Article]
      Predicting the phenotypes resulting from molecular perturbations is one of the key challenges in genetics. Both forward and reverse genetic screen are employed to identify the molecular mechanisms underlying phenotypes and disease, and these resulted in a large number of genotype–phenotype association being available for humans and model organisms. Combined with recent advances in machine learning, it may now be possible to predict human phenotypes resulting from particular molecular aberrations. We developed DeepPheno, a neural network based hierarchical multi-class multi-label classification method for predicting the phenotypes resulting from loss-of-function in single genes. DeepPheno uses the functional annotations with gene products to predict the phenotypes resulting from a loss-of-function; additionally, we employ a two-step procedure in which we predict these functions first and then predict phenotypes. Prediction of phenotypes is ontology-based and we propose a novel ontology-based classifier suitable for very large hierarchical classification tasks. These methods allow us to predict phenotypes associated with any known protein-coding gene. We evaluate our approach using evaluation metrics established by the CAFA challenge and compare with top performing CAFA2 methods as well as several state of the art phenotype prediction approaches, demonstrating the improvement of DeepPheno over established methods. Furthermore, we show that predictions generated by DeepPheno are applicable to predicting gene–disease associations based on comparing phenotypes, and that a large number of new predictions made by DeepPheno have recently been added as phenotype databases.
    • Millimeter-Deep Detection of Single Shortwave-Infrared-Emitting Polymer Dots through Turbid Media

      Piwonski, Hubert Marek; Wang, Yang; Li, Wei; Michinobu, Tsuyoshi; Habuchi, Satoshi (Nano Letters, American Chemical Society (ACS), 2020-11-18) [Article]
      Fluorescence imaging at longer wavelengths, especially in the shortwave-infrared (SWIR: 1000-1700 nm) region, leads to a substantial decrease in light attenuation, scattering, and background autofluorescence, thereby enabling enhanced penetration into biological tissues. The limited selection of fluorescent probes is a major bottleneck in SWIR fluorescence imaging. Here, we develop SWIR-emitting nanoparticles composed of donor-acceptor-type conjugated polymers. The bright SWIR fluorescence of the polymer dots (primarily attributable to their large absorption cross-section and high fluorescence saturation intensity (as high as 113 kW·cm-2)) enables the unprecedented detection of single particles as small as 14 nm through millimeter-thick turbid media. Unlike most SWIR-emitting nanomaterials, which have an excited-state lifetime in the range of microseconds to milliseconds, our polymer dots exhibit a subnanosecond excited-state lifetime. These characteristics enable us to demonstrate new time-gated single-particle imaging with a high signal-to-background ratio. These findings expand the range of potential applications of single-particle deep-tissue imaging.
    • MXene-Modulated Electrode/SnO2 Interface Boosting Charge Transport in Perovskite Solar Cells

      Wang, Yunfan; Xiang, Pan; Ren, Aobo; Lai, Huagui; Zhang, Zhuoqiong; Xuan, Zhipeng; Wan, Zhenxi; Zhang, Jingquan; Hao, Xia; Wu, Lili; Sugiyama, Masakazu; Schwingenschlögl, Udo; Liu, Cai; Tang, Zeguo; Wu, Jiang; Wang, Zhiming; Zhao, Dewei (ACS Applied Materials & Interfaces, American Chemical Society (ACS), 2020-11-17) [Article]
      Interface engineering is imperative to boost the extraction capability in perovskite solar cells (PSCs). We propose a promising approach to enhance the electron mobility and charge transfer ability of tin oxide (SnO2) electron transport layer (ETL) by introducing a two-dimensional carbide (MXene) with strong interface interaction. The MXene-modified SnO2 ETL also offers a preferable growth platform for perovskite films with reduced trap density. Through a spatially resolved imaging technique, profoundly reduced non-radiative recombination and charge transport losses in PSCs based on MXene-modified SnO2 are also observed. As a result, the PSC achieves an enhanced efficiency of 20.65% with ultralow saturated current density and negligible hysteresis. We provide an in-depth mechanistic understanding of MXene interface engineering, offering an alternative approach to obtain efficient PSCs.
    • NodePy: A package for the analysis of numerical ODE solvers

      Ketcheson, David I.; Ranocha, Hendrik; Parsani, Matteo; Waheed, Umair bin; Hadjimichael, Yiannis (Journal of Open Source Software, The Open Journal, 2020-11-17) [Article]
      Ordinary differential equations (ODEs) are used to model a vast range of physical and other phenomena. They also arise in the discretization of partial differential equations. In most cases, solutions of differential equations must be approximated by numerical methods. The study of the properties of numerical methods for ODEs comprises an important and large body of knowledge. NodePy (available from, with documentation at is a software package for designing and studying the properties of numerical ODE solvers. For the most important classes of methods, NodePy can automatically assess their stability, accuracy, and many other properties. NodePy has also been used as a catalog of coefficients for time integration methods in PDE solver codes.
    • Investigating Water Injection in Single-Cylinder Gasoline Spark-Ignited Engines at Fixed Speed

      Singh, Eshan; Hlaing, Ponnya; Dibble, Robert W. (Energy & Fuels, American Chemical Society (ACS), 2020-11-17) [Article]
      Increasingly stringent emission norms have always brought forth innovative measures to improve engine efficiency. Spark-ignited engines have been limited in efficiency, traditionally by knock, and more recently by preignition too. Water injection has recently regained interest as a knock suppressant. The current work explored water injection via port and direct injection at a fixed engine speed of 2000 rpm and varying engine loads. The data presented in this work emphasize that the gains from using water injection are best realized at a specific injection timing (neither too early nor too late), and the effectiveness of water in suppressing knock decreases rapidly with increasing water mass injected. In general, direct water injection offers a more significant knock reduction because of better utilization of the charge cooling effect than port water injection. Engine-out emission confirms a reduction in NOx and CO, while the HC emissions increased when using water injection. No preignition events were observed at the engine load up to 27 bar. Chemical kinetics simulations confirm the role of water in suppressing reactivity under the operating conditions considered in the current study.
    • Single-Crystalline All-Oxide α–γ–β Heterostructures for Deep-Ultraviolet Photodetection

      Li, Kuang-Hui; Kang, Chun Hong; Min, Jung-Hong; Alfaraj, Nasir; Liang, Jian-Wei; Braic, Laurentiu; Guo, Zaibing; Hedhili, Mohamed N.; Ng, Tien Khee; Ooi, Boon S. (ACS Applied Materials & Interfaces, American Chemical Society (ACS), 2020-11-17) [Article]
      Recent advancements in gallium oxide (Ga2O3)-based heterostructures have allowed optoelectronic devices to be used extensively in the fields of power electronics and deep-ultraviolet photodetection. While most previous research has involved realizing single-crystalline Ga2O3 layers on native substrates for high conductivity and visible-light transparency, presented and investigated herein is a single-crystalline β-Ga2O3 layer grown on an α-Al2O3 substrate through an interfacial γ-In2O3 layer. The single-crystalline transparent conductive oxide layer made of wafer-scalable γ-In2O3 provides high carrier transport, visible-light transparency, and antioxidation properties that are critical for realizing vertically oriented heterostructures for transparent oxide photonic platforms. Physical characterization based on X-ray diffraction and high-resolution transmission electron microscopy imaging confirms the single-crystalline nature of the grown films and the crystallographic orientation relationships among the monoclinic β-Ga2O3, cubic γ-In2O3, and trigonal α-Al2O3, while the elemental composition and sharp interfaces across the heterostructure are confirmed by Rutherford backscattering spectrometry. Furthermore, the energy-band offsets are determined by X-ray photoelectron spectroscopy at the β-Ga2O3/γ-In2O3 interface, elucidating a type-II heterojunction with conduction- and valence-band offsets of 0.16 and 1.38 eV, respectively. Based on the single-crystalline β-Ga2O3/γ-In2O3/α-Al2O3 all-oxide heterostructure, a vertically oriented DUV photodetector is fabricated that exhibits a high photoresponsivity of 94.3 A/W, an external quantum efficiency of 4.6 × 104%, and a specific detectivity of 3.09 × 1012 Jones at 250 nm. The present demonstration lays a strong foundation for and paves the way to future all-oxide-based transparent photonic platforms.
    • Ultra-compact terahertz plasmonic wavelength diplexer

      Yuan, Mingrui; Wang, Qingwei; Li, Yanfeng; Zhang, Xixiang; Han, Jiaguang; Zhang, Weili (Applied Optics, The Optical Society, 2020-11-17) [Article]
      Terahertz (THz) spoof surface plasmon polariton (SPP) waveguides can provide subwavelength confinement, which makes it possible for the THz waves to transmit at low loss over long distances along a metallic surface. In this work, an ultra-compact wavelength diplexer formed by THz spoof SPP waveguiding structures is reported on the design and actualization. By adding a certain number of periodic pillars in the coupling part of the directional coupler, the refractive index of the anti-symmetrically distributed odd modes can be engineered, thereby adjusting the coupling length. By adjusting the periodic pillar parameters properly, the SPP modes at two target frequencies will be coupled in the device for an odd or even number of times, so that SPP modes at these two frequencies can be coupled out from different ports. The length of the wavelength diplexer is 1.6 mm, which is about 12.8% of its traditional counterpart. Minimum simulated transmittances of -24.34 dB and -26.27 dB can be obtained at 0.637 THz and 0.667 THz, respectively. The insertion losses at the two operating frequencies are less than 0.46 dB, and the extinction ratios are both better than 19 dB. By cascading the proposed diplexers, a compact wavelength demultiplexer with more channels can be obtained, which has important applications for future THz integrated communication systems.
    • Polyurethanes from Direct Organocatalytic Copolymerization of p-Tosyl Isocyanate with Epoxides.

      Gnanou, Yves; Jia, Mingchen; Hadjichristidis, Nikos; Feng, Xiaoshuang (Angewandte Chemie (International ed. in English), Wiley, 2020-11-17) [Article]
      The direct copolymerization of p -tosyl isocyanate (TSI) with epoxides, initiated by onium salts in the presence of trialkylborane, to produce polyurethanes is reported. The rate of copolymerization and the (regio)selectivity were investigated in relation to the trialkylborane and initiator used. Under optimized conditions such copolymerizations have been successfully performed for a wide range of epoxides, including ethylene oxide, propylene oxide, 1-octene oxide, cyclohexene oxide, and allyl glycidyl ether. These copolymerizations afford a new category of polyurethanes, clear of side products such as cyclic oxazolidinone, isocyanurate, and poly(isocyanate) linkages. The experimental conditions used in this work are compatible with those for the organocatalytic (co)polymerization of other oxygenated monomers and CO 2 , holding the potential for their terpolymerization with p -tosyl isocyanate and the development of new materials with unprecedented properties.
    • Multiple epitaxial lateral overgrowth of GaN thin films using a patterned graphene mask by metal organic chemical vapor deposition

      Lee, Jun-Yeob; Min, Jung-Hong; Bae, Si-Young; Park, Mun-Do; Jeong, Woo-Lim; Park, Jeong-Hwan; Kang, Chang-Mo; Lee, Dong-Seon (Journal of Applied Crystallography, International Union of Crystallography (IUCr), 2020-11-17) [Article]
      Single-crystal gallium nitride (GaN) thin films were grown using a graphene mask via multiple epitaxial lateral overgrowth (multiple-ELOG). During the growth process, the graphene mask self-decomposed to enable the emergence of a GaN film with a thickness of several hundred nanometres. This is in contrast to selective area growth of GaN using an SiO2 mask leading to the well known hexagonal-pyramid shape under the same growth conditions. The multiple-ELOG GaN had a single-crystalline wurtzite structure corresponding to the crystallinity of the GaN template, which was confirmed with electron backscatter diffraction measurements. An X-ray diffraction rocking curve of the asymmetric 102 reflection showed that the FWHM for the multiple-ELOG GaN decreased to 405 from 540′′ for the underlying GaN template. From these results, the self-decomposition of the graphene mask during ELOG was experimentally proven to be affected by the GaN decomposition rather than the high-temperature/H2 growth conditions.
    • DFT-based investigation of different properties for transition metal-doped germanium TMGen (TM = Ru, Rh; n = 1-20) clusters.

      Benaida, Meriem; Aiadi, Kamal Eddine; Mahtout, Sofiane; Bentouila, Omar; Djaadi, Soumaia; Harb, Moussab (Journal of molecular modeling, Springer Science and Business Media LLC, 2020-11-17) [Article]
      The geometries and energetic, electronic, and magnetic features of transition metal-doped germanium (TMGen with TM = Ru, Rh; n = 1-20) clusters are systematically studied by means of first principle computations on the basis of the density functional theory (DFT) approach. The doping TM atom largely participates to strengthen the Gen cluster stability by increasing the binding energies. A good stability is obtained for RuGe12, RhGe12, and RhGe14 clusters. The various explored isomers of TMGen clusters possess a total spin magnetic moment going from 0 to 2μB, except for RhGe2 with 3μB. These results open nice perspectives of these good candidate clusters for applications in nanoelectronics and nanotechnologies.
    • Paper as a Substrate and an Active Material in Paper Electronics

      Khan, Sherjeel M.; Nassar, Joanna M.; Hussain, Muhammad Mustafa (ACS Applied Electronic Materials, American Chemical Society (ACS), 2020-11-16) [Article]
      Paper is an essential part of our daily life in many different ways. It is made by compressing cellulose fibers sourced from wood into thin sheets. Paper is an inherently flexible material which can transport liquids through its medium by capillary action without the need of external force. The mesh network of cellulose in paper gives it a unique set of mechanical properties. Owing to its exclusive and advantageous properties, paper is being used as an active material and a substrate in electronics. Paper as an active material means that paper is utilized in its intrinsic form without modifications. Activated (or functionalized) paper has been widely exploited in many applications, but in order to take true advantage of all the beneficial properties of paper, it needs to be used in its natural produced form. Notably, paper is employed in humidity sensors, pressure sensors, and MEMS devices in its natural form. Additionally, paper is used as a substrate in additively manufactured and origami-inspired electronic devices. Here, we present an overview of how paper is used to make fully flexible and low-cost devices. Furthermore, the emergence of paper-based point-of-care devices is briefly discussed.
    • Parity-Time Symmetry and Exceptional Points for Flexural-Gravity Waves in Buoyant Thin-Plates

      Farhat, Mohamed; Guenneau, Sebastien; Chen, Pai-Yen; Wu, Ying (Crystals, MDPI AG, 2020-11-16) [Article]
      We derive and apply a transfer matrix method (M-matrix) coupling liquid surface waves and flexural-gravity waves in buoyant thin elastic plates. We analyze the scattering matrix (S-matrix) formalism for such waves propagating within a Fabry-Perot like system, which are solutions of a sixth order partial differential equation (PDE) supplied with adequate boundary conditions. We develop a parity-time (PT)-symmetry theory and its applications to thin elastic floating plates. The sixth order PDE governing the propagation of these waves leads to six by six M and S matrices, and results in specific physical properties of the PT-symmetric elastic plate systems. We show the effect of geometry and gain/loss on the asymmetric propagation of flexural-gravity waves, as well as a Fano-like line-shape of the reflection signature. Importantly, we show the possibility of obtaining coherent perfect absorber-laser (CPAL) using simple thin structures.