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Recent Submissions

  • Synthesis of gold(I)-trifluoromethyl complexes and their role in generating spectroscopic evidence for a gold(I)-difluorocarbene species.

    Nolan, Steven Patrick; Vanden Broeck, Sofie M P; Nelson, David J; Collado, Alba; Falivene, Laura; Cavallo, Luigi; Cordes, David B; Slawin, Alexandra M Z; Van Hecke, Kristof; Nahra, Fady; Cazin, Catherine S J (Chemistry (Weinheim an der Bergstrasse, Germany), Wiley, 2021-04-06) [Article]
    Readily-prepared and bench-stable [Au(CF 3 )(NHC)] compounds were synthesized using new methodologies, starting from [Au(OH)(NHC)], [Au(Cl)(NHC)] or [Au(L)(NHC)]HF 2 precursors (NHC = N-heterocyclic carbene). The mechanism of formation of these species was investigated. Consequently, a new and straightforward strategy for the mild and selective cleavage of a single carbon-fluorine bond from [Au(CF 3 )(NHC)] complexes was attempted and found to be reversible in the presence of an additional nucleophilic fluoride source. This straightforward technique has led to the unprecedented spectroscopic observation of a gold(I)-NHC difluorocarbene species.
  • Lithium-Ion Desolvation Induced by Nitrate Additives Reveals New Insights into High Performance Lithium Batteries

    Wahyudi, Wandi; Ladelta, Viko; Tsetseris, Leonidas; Alsabban, Merfat; Guo, Xianrong; Yengel, Emre; Faber, Hendrik; Adilbekova, Begimai; Seitkhan, Akmaral; Emwas, Abdul-Hamid; Hedhili, Mohamed N.; Li, Lain-Jong; Tung, Vincent; Hadjichristidis, Nikos; Anthopoulos, Thomas D.; Ming, Jun (Advanced Functional Materials, Wiley, 2021-04-02) [Article]
    Electrolyte additives have been widely used to address critical issues in current metal (ion) battery technologies. While their functions as solid electrolyte interface forming agents are reasonably well-understood, their interactions in the liquid electrolyte environment remain rather elusive. This lack of knowledge represents a significant bottleneck that hinders the development of improved electrolyte systems. Here, the key role of additives in promoting cation (e.g., Li+) desolvation is unraveled. In particular, nitrate anions (NO3−) are found to incorporate into the solvation shells, change the local environment of cations (e.g., Li+) as well as their coordination in the electrolytes. The combination of these effects leads to effective Li+ desolvation and enhanced battery performance. Remarkably, the inexpensive NaNO3 can successfully substitute the widely used LiNO3 offering superior long-term stability of Li+ (de-)intercalation at the graphite anode and suppressed polysulfide shuttle effect at the sulfur cathode, while enhancing the performance of lithium–sulfur full batteries (initial capacity of 1153 mAh g−1 at 0.25C) with Coulombic efficiency of ≈100% over 300 cycles. This work provides important new insights into the unexplored effects of additives and paves the way to developing improved electrolytes for electrochemical energy storage applications.
  • Theory-Guided Synthesis of Highly Luminescent Colloidal Cesium Tin Halide Perovskite Nanocrystals

    Liu, Qi; Yin, Jun; Zhang, Bin-Bin; Chen, Jia-Kai; Zhou, Yang; Zhang, Lu-Min; Wang, Lu-Ming; Zhao, Qing; Hou, Jingshan; Shu, Jie; Song, Bo; Shirahata, Naoto; Bakr, Osman; Mohammed, Omar F.; Sun, Hong-Tao (Journal of the American Chemical Society, American Chemical Society (ACS), 2021-04-01) [Article]
    The synthesis of highly luminescent colloidal CsSnX<sub>3</sub> (X = halogen) perovskite nanocrystals (NCs) remains a long-standing challenge due to the lack of a fundamental understanding of how to rationally suppress the formation of structural defects that significantly influence the radiative carrier recombination processes. Here, we develop a theory-guided, general synthetic concept for highly luminescent CsSnX<sub>3</sub> NCs. Guided by density functional theory calculations and molecular dynamics simulations, we predict that, although there is an opposing trend in the chemical potential-dependent formation energies of various defects, highly luminescent CsSnI<sub>3</sub> NCs with narrow emission could be obtained through decreasing the density of tin vacancies. We then develop a colloidal synthesis strategy that allows for rational fine-tuning of the reactant ratio in a wide range but still leads to the formation of CsSnI<sub>3</sub> NCs. By judiciously adopting a tin-rich reaction condition, we obtain narrow-band-emissive CsSnI<sub>3</sub> NCs with a record emission quantum yield of 18.4%, which is over 50 times larger than those previously reported. Systematic surface-state characterizations reveal that these NCs possess a Cs/I-lean surface and are capped with a low density of organic ligands, making them an excellent candidate for optoelectronic devices without any postsynthesis ligand management. We showcase the generalizability of our concept by further demonstrating the synthesis of highly luminescent CsSnI<sub>2.5</sub>Br<sub>0.5</sub> and CsSnI<sub>2.25</sub>Br<sub>0.75</sub> NCs. Our findings not only highlight the value of computation in guiding the synthesis of high-quality colloidal perovskite NCs but also could stimulate intense efforts on tin-based perovskite NCs and accelerate their potential applications in a range of high-performance optoelectronic devices.
  • Machine-driven earth exploration: Artificial intelligence in oil and gas

    Alkhalifah, Tariq Ali; Almomin, Ali; Naamani, Ali (The Leading Edge, Society of Exploration Geophysicists, 2021-04) [Article]
    Artificial intelligence (AI), specifically machine learning (ML), has emerged as a powerful tool to address many of the challenges we face as we try to illuminate the earth and make the proper prediction of its content. From fault detection, to salt boundary mapping, to image resolution enhancements, the quest to teach our computing devices how to perform these tasks accurately, as well as quantify the accuracy, has become a feasible and sought-after objective. Recent advances in ML algorithms and availability of the modules to apply such algorithms enabled geoscientists to focus on potential applications of such tools. As a result, we held the virtual workshop, Artificially Intelligent Earth Exploration Workshop: Teaching the Machine How to Characterize the Subsurface, 23–26 November 2020.
  • Synergy processing of diverse ground-based remote sensing and in situ data using the GRASP algorithm: applications to radiometer, lidar and radiosonde observations

    Lopatin, Anton; Dubovik, Oleg; Fuertes, David; Stenchikov, Georgiy L.; Lapyonok, Tatyana; Veselovskii, Igor; Wienhold, Frank G.; Shevchenko, Illia; Hu, Qiaoyun; Parajuli, Sagar (Atmospheric Measurement Techniques, Copernicus GmbH, 2021-04-01) [Article]
    Abstract. The exploration of aerosol retrieval synergies from diverse combinations of ground-based passive Sun-photometric measurements with collocated active lidar ground-based and radiosonde observations using versatile Generalized Retrieval of Atmosphere and Surface Properties (GRASP) algorithm is presented. Several potentially fruitful aspects of observation synergy were considered. First, a set of passive and active ground-based observations collected during both day- and nighttime was inverted simultaneously under the assumption of temporal continuity of aerosol properties. Such an approach explores the complementarity of the information in different observations and results in a robust and consistent processing of all observations. For example, the interpretation of the nighttime active observations usually suffers from the lack of information about aerosol particles sizes, shapes and complex refractive index. In the realized synergy retrievals, the information propagating from the nearby Sun-photometric observations provides sufficient constraints for reliable interpretation of both day- and nighttime lidar observations. Second, the synergetic processing of such complementary observations with enhanced information content allows for optimizing the aerosol model used in the retrieval. Specifically, the external mixture of several aerosol components with predetermined sizes, shapes and composition has been identified as an efficient approach for achieving reliable retrieval of aerosol properties in several situations. This approach allows for achieving consistent and accurate aerosol retrievals from processing stand-alone advanced lidar observations with reduced information content about aerosol columnar properties. Third, the potential of synergy processing of the ground-based Sun-photometric and lidar observations, with the in situ backscatter sonde measurements was explored using the data from KAUST.15 and KAUST.16 field campaigns held at King Abdullah University of Science and Technology (KAUST) in the August of 2015 and 2016. The inclusion of radiosonde data has been demonstrated to provide significant additional constraints to validate and improve the accuracy and scope of aerosol profiling. The results of all retrieval setups used for processing both synergy and stand-alone observation data sets are discussed and intercompared.
  • Optically and Electrocatalytically Decoupled Si Photocathodes with a Porous Carbon Nitride Catalyst for Nitrogen Reduction with Over 61.8% Faradaic Efficiency

    Peramaiah, Karthik; Ramalingam, Vinoth; Fu, Hui-Chun; Alsabban, Merfat; Ahmad, Rafia; Cavallo, Luigi; Tung, Vincent; Huang, Kuo-Wei; He, Jr-Hau (Advanced Materials, Wiley, 2021-03-31) [Article]
    The photoelectrochemical (PEC) approach is attractive as a promising route for the nitrogen reduction reaction (NRR) toward ammonia (NH<sub>3</sub> ) synthesis. However, the challenges in synergistic management of optical, electrical, and catalytic properties have limited the efficiency of PEC NRR devices. Herein, to enhance light-harvesting, carrier separation/transport, and the catalytic reactions, a concept of decoupling light-harvesting and electrocatalysis by employing a cascade n<sup>+</sup> np<sup>+</sup> -Si photocathode is implemented. Such a decoupling design not only abolishes the parasitic light blocking but also concurrently improves the optical and electrical properties of the n<sup>+</sup> np<sup>+</sup> -Si photocathode without compromising the efficiency. Experimental and density functional theory studies reveal that the porous architecture and N-vacancies promote N<sub>2</sub> adsorption of the Au/porous carbon nitride (PCN) catalyst. Impressively, an n<sup>+</sup> np<sup>+</sup> -Si photocathode integrating the Au/PCN catalyst exhibits an outstanding PEC NRR performance with maximum Faradaic efficiency (FE) of 61.8% and NH<sub>3</sub> production yield of 13.8 µg h<sup>-1</sup> cm<sup>-2</sup> at -0.10 V versus reversible hydrogen electrode (RHE), which is the highest FE at low applied potential ever reported for the PEC NRR.
  • The Effect of the Oleophobicity Deterioration of a Membrane Surface on Its Rejection Capacity: A Computational Fluid Dynamics Study

    Salama, Amgad; Alyan, Adel; El-Amin, Mohamed F.; Sun, Shuyu; Zhang, Tao; Zoubeik, Mohamed (Membranes, MDPI AG, 2021-03-31) [Article]
    In this work, the effects of the deteriorating affinity-related properties of membranes due to leaching and erosion on their rejection capacity were studied via computational fluid dynamics (CFD). The function of affinity-enhancing agents is to modify the wettability state of the surface of a membrane for dispersed droplets. The wettability conditions can be identified by the contact angle a droplet makes with the surface of the membrane upon pinning. For the filtration of fluid emulsions, it is generally required that the surface of the membrane is nonwetting for the dispersed droplets such that the interfaces that are formed at the pore openings provide the membrane with a criterion for the rejection of dispersals. Since materials that make up the membrane do not necessarily possess the required affinity, it is customary to change it by adding affinity-enhancing agents to the base material forming the membrane. The bonding and stability of these materials can be compromised during the lifespan of a membrane due to leaching and erosion (in crossflow filtration), leading to a deterioration of the rejection capacity of the membrane. In order to investigate how a decrease in the contact angle can lead to the permeation of droplets that would otherwise get rejected, a CFD study was conducted. In the CFD study, a droplet was released in a crossflow field that involved a pore opening and the contact angle was considered to decrease with time as a consequence of the leaching of affinity-enhancing agents. The CFD analysis revealed that the decrease in the contact angle resulted in the droplet spreading over the surface more. Furthermore, the interface that was formed at the entrance of the pore opening flattened as the contact angle decreased, leading the interface to advance more inside the pore. The droplet continued to pass over the pore opening until the contact angle reached a certain value, at which point, the droplet became pinned at the pore opening.
  • Microfluidic Integrated Organic Electrochemical Transistor with a Nanoporous Membrane for Amyloid-β Detection

    Koklu, Anil; Wustoni, Shofarul; Musteata, Valentina-Elena; Ohayon, David; Moser, Maximilian; McCulloch, Iain; Nunes, Suzana Pereira; Inal, Sahika (ACS Nano, American Chemical Society (ACS), 2021-03-30) [Article]
    Alzheimer’s disease (AD) is a neurodegenerative disorder associated with a severe loss in thinking, learning, and memory functions of the brain. To date, no specific treatment has been proven to cure AD, with the early diagnosis being vital for mitigating symptoms. A common pathological change found in AD-affected brains is the accumulation of a protein named amyloid-β (Aβ) into plaques. In this work, we developed a micron-scale organic electrochemical transistor (OECT) integrated with a microfluidic platform for the label-free detection of Aβ aggregates in human serum. The OECT channel–electrolyte interface was covered with a nanoporous membrane functionalized with Congo red (CR) molecules showing a strong affinity for Aβ aggregates. Each aggregate binding to the CR-membrane modulated the vertical ion flow toward the channel, changing the transistor characteristics. Thus, the device performance was not limited by the solution ionic strength nor did it rely on Faradaic reactions or conformational changes of bioreceptors. The high transconductance of the OECT, the precise porosity of the membrane, and the compactness endowed by the microfluidic enabled the Aβ aggregate detection over eight orders of magnitude wide concentration range (femtomolar–nanomolar) in 1 μL of human serum samples. We expanded the operation modes of our transistors using different channel materials and found that the accumulation-mode OECTs displayed the lowest power consumption and highest sensitivities. Ultimately, these robust, low-power, sensitive, and miniaturized microfluidic sensors helped to develop point-of-care tools for the early diagnosis of AD.
  • Near-surface real-time seismic imaging using parsimonious interferometry

    Hanafy, Sherif M.; Hoteit, Hussein; Li, Jing; Schuster, Gerard T. (Scientific Reports, Springer Science and Business Media LLC, 2021-03-30) [Article]
    AbstractResults are presented for real-time seismic imaging of subsurface fluid flow by parsimonious refraction and surface-wave interferometry. Each subsurface velocity image inverted from time-lapse seismic data only requires several minutes of recording time, which is less than the time-scale of the fluid-induced changes in the rock properties. In this sense this is real-time imaging. The images are P-velocity tomograms inverted from the first-arrival times and the S-velocity tomograms inverted from dispersion curves. Compared to conventional seismic imaging, parsimonious interferometry reduces the recording time and increases the temporal resolution of time-lapse seismic images by more than an order-of-magnitude. In our seismic experiment, we recorded 90 sparse data sets over 4.5 h while injecting 12-tons of water into a sand dune. Results show that the percolation of water is mostly along layered boundaries down to a depth of a few meters, which is consistent with our 3D computational fluid flow simulations and laboratory experiments. The significance of parsimonious interferometry is that it provides more than an order-of-magnitude increase of temporal resolution in time-lapse seismic imaging. We believe that real-time seismic imaging will have important applications for non-destructive characterization in environmental, biomedical, and subsurface imaging.
  • Automatic seismic phase picking based on unsupervised machine learning classification and content information analysis

    Valero Cano, Eduardo; Akram, Jubran; Peter, Daniel B. (GEOPHYSICS, Society of Exploration Geophysicists, 2021-03-29) [Article]
    Accurate identification and picking of P- and S-wave arrivals is important in earthquake and exploration seismology. Often, existing algorithms lack in automation, multi-phase classification and picking, as well as performance accuracy. A new fully-automated fourth-step workflow for efficient classification and picking of P- and S-wave arrival times on microseismic datasets is presented. First, time intervals with possible arrivals on the waveform recordings are identified using the fuzzy c-means clustering algorithm. Second, these signal intervals are classified as corresponding to P, S, or unidentified waves using the polarization attributes of the waveforms contained within. Third, the P-, S-, and unidentified-waves arrival times are picked using the Akaike information criterion picker on the corresponding intervals. Fourth, unidentified waves are classified as P or S based on the arrivals moveouts. The application of the workflow on synthetic and real microseismic datasets shows that it yields accurate arrival picks for both high and low signal-to-noise ratio waveforms.
  • 25 years of Reticular Chemistry

    Freund, Ralph; Canossa, Stefano; Cohen, Seth M.; Yan, Wei; Deng, Hexiang; Guillerm, Vincent; Eddaoudi, Mohamed; Madden, David G.; Fairen-Jimenez, David; Lyu, Hao; Macreadie, Lauren K.; Ji, Zhe; Zhang, Yuanyuan; Wang, Bo; Haase, Frederik; Wöll, Christof; Zaremba, Orysia; Andreo, Jacopo; Wuttke, Stefan; Diercks, Christian S. (Angewandte Chemie International Edition, Wiley, 2021-03-29) [Article]
    At its core, reticular chemistry has translated the precision and expertise of organic and inorganic synthesis to the solid state. While initial excitement over metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) was undoubtedly fueled by their unprecedented porosity and surface areas, the most profound scientific innovation of the field has been the elaboration of design strategies for the synthesis of extended crystalline solids through strong directional bonds. In this contribution we highlight the different classes of reticular materials that have been developed, how these frameworks can be functionalized and how complexity can be introduced into their backbones. Finally, we show how the structural control over these materials is being extended from the molecular scale to their crystal morphology and shape on the nanoscale, all the way to their shaping on the bulk scale.
  • Synthesis and Characterization of Iron-Doped TiO2 Nanoparticles Using Ferrocene from Flame Spray Pyrolysis

    Ismail, Mohamed; Hedhili, Mohamed N.; Anjum, Dalaver H.; Singaravelu, Venkatesh; Chung, Suk Ho (Catalysts, MDPI AG, 2021-03-29) [Article]
    Iron-doped titanium dioxide nanoparticles, with Fe/Ti atomic ratios from 0% to 10%, were synthesized by flame spray pyrolysis (FSP), employing a single-step method. Ferrocene, being nontoxic and readily soluble in liquid hydrocarbons, was used as the iron source, while titanium tetraisopropoxide (TTIP) was used as the precursor for TiO2. The general particle characterization and phase description were examined using ICP-OES, XRD, BET, and Raman spectroscopy, whereas the XPS technique was used to study the surface chemistry of the synthesized particles. For particle morphology, HRTEM with EELS and EDS analyses were used. Optical and magnetic properties were examined using UV–vis and SQUID, respectively. Iron doping to TiO2 nanoparticles promoted rutile phase formation, which was minor in the pure TiO2 particles. Iron-doped nanoparticles exhibited a uniform iron distribution within the particles. XPS and UV–vis results revealed that Fe2+ was dominant for lower iron content and Fe3+ was common for higher iron content and the iron-containing particles had a contracted band gap of ~1 eV lower than pure TiO2 particles with higher visible light absorption. SQUID results showed that doping TiO2 with Fe changed the material to be paramagnetic. The generated nanoparticles showed a catalytic effect for dye-degradation under visible light.
  • InGaN-based nanowires development for energy harvesting and conversion applications

    Zhang, Huafan; Min, Jung-Wook; Gnanasekar, Paulraj; Ng, Tien Khee; Ooi, Boon S. (Journal of Applied Physics, AIP Publishing, 2021-03-28) [Article]
    This Tutorial teaches the essential development of nitrogen-plasma-assisted molecular-beam-epitaxy grown InGaN nanowires as an application-inspired platform for energy harvesting and conversion applications by growing dislocation- and strain-relieved axial InGaN-based nanowires. The Tutorial aims to shed light on the interfacial, surface, electrical, and photoelectrochemical characteristics of InGaN nanowires through nanoscale and ultrafast characterizations. Understanding the interrelated optical-physical properties proved critical in the development of renewable-energy harvesting and energy conversion devices. Benefiting from their unique aspect ratio and surface-to-volume ratio, semiconductor properties, and piezoelectric properties, the group-III-nitride nanowires, especially InGaN nanowires, are promising for clean energy conversion applications, including piezotronic/piezo-phototronic and solar-to-clean-fuel energy-conversion.
  • Low-Fidelity End-to-End Video Encoder Pre-training for Temporal ActionLocalization

    Xu, Mengmeng; Perez-Ru, Juan-Manuel; Zhu, Xiatian; Ghanem, Bernard; Martinez, Brais (arXiv, 2021-03-28) [Preprint]
    Temporal action localization (TAL) is a fundamental yet challenging task in video understanding. Existing TAL methods rely on pre-training a video encoder through action classification supervision. This results in a task discrepancy problem for the video encoder -- trained for action classification, but used for TAL. Intuitively, end-to-end model optimization is a good solution. However, this is not operable for TAL subject to the GPU memory constraints, due to the prohibitive computational cost in processing long untrimmed videos. In this paper, we resolve this challenge by introducing a novel low-fidelity end-to-end (LoFi) video encoder pre-training method. Instead of always using the full training configurations for TAL learning, we propose to reduce the mini-batch composition in terms of temporal, spatial or spatio-temporal resolution so that end-to-end optimization for the video encoder becomes operable under the memory conditions of a mid-range hardware budget. Crucially, this enables the gradient to flow backward through the video encoder from a TAL loss supervision, favourably solving the task discrepancy problem and providing more effective feature representations. Extensive experiments show that the proposed LoFi pre-training approach can significantly enhance the performance of existing TAL methods. Encouragingly, even with a lightweight ResNet18 based video encoder in a single RGB stream, our method surpasses two-stream ResNet50 based alternatives with expensive optical flow, often by a good margin.
  • Effective Doping of Square/Octagon-Phase Arsenene by Adsorption of Organic Molecules

    Zhao, Ning; Schwingenschlögl, Udo (Advanced Theory and Simulations, Wiley, 2021-03-27) [Article]
    Adsorption of organic molecules can be a better choice than traditional chemical doping to achieve effective doping of 2D materials. The adsorption of organic molecules on square/octagon-phase (S/O-phase) arsenene is investigated and promoted the possibility of developing p–n junctions. In particular, it is found that adsorption of F4-TCNQ or TCNE molecules leads to effective p-doping. Adsorption of DMPD or TTF molecules leads to less effective n-doping. Interestingly, in the case of TTF adsorption strain engineering can be used to greatly improve the material properties. Therefore, both effective n- and p-doping of S/O-phase arsenene can be realized.
  • Interseismic deformation from Sentinel-1 burst-overlap interferometry: Application to the southern Dead Sea fault

    Li, Xing; Jonsson, Sigurjon; Cao, Yunmeng (Wiley, 2021-03-26) [Preprint]
    Interferometric Synthetic Aperture Radar (InSAR) data are increasingly being used to map interseismic deformation with ascending and descending-orbit observations allowing for resolving for the near-east and vertical displacement components. The north component has, however, been difficult to retrieve due to the limited sensitivity of standard InSAR observations in that direction. Here we address this problem by using time-series analysis of along-track interferometric observations in burst-overlap areas of the TOPS imaging mode of the Sentinel-1 radar satellites. We apply this method to the southern part of the near-north striking Dead Sea transform fault to show that the ~5 mm/year relative motion is well recovered. Furthermore, the results indicate the locking depth of the fault decreases towards the south as it enters the transtensional Gulf of Aqaba basin. Our results show that time-series analysis of burst-overlap interferometric observations can be used to obtain meaningful interseismic deformation rates of slow-moving and northerly-striking faults.
  • Coastal circulation and water transport properties of the Red Sea Project lagoon

    Zhan, Peng; Krokos, Georgios; Langodan, Sabique; Guo, Daquan; Dasari, Hari Prasad; Papadopoulos, Vassilis P.; Lermusiaux, Pierre F.J.; Knio, Omar; Hoteit, Ibrahim (Ocean Modelling, Elsevier BV, 2021-03-26) [Article]
    The Red Sea Project (RSP) is based on a coastal lagoon with over 90 pristine islands. The project intends to transform the Red Sea coast into a world-class tourist destination. To better understand the regional dynamics and water exchange scenarios in the lagoon, a high-resolution numerical model is implemented. The general and tidal circulation dynamics are then investigated with a particular focus on the response of the lagoon to strong wind jets. Significant variations in winter and summer circulation patterns are identified. The tidal amplitude inside the lagoon is greater than that outside, with strong tidal currents passing over its surrounding coral reef banks. The lagoon rapidly responds to the strong easterly wind jets that occur mainly in winter; it develops a reverse flow at greater depths, and the coastal water elevation is instantly affected. Lagrangian particle simulations are conducted to study the residence time of water in the lagoon. The results suggest that water renewal is slow in winter. Analysis of the Lagrangian coherent structures (LCS) reveals that water renewal is largely linked to the circulation patterns in the lagoon. In winter, the water becomes restricted in the central lagoon with only moderate exchange, whereas in summer, more circulation is observed with a higher degree of interaction between the central lagoon and external water. The results of LCS also highlight the tidal contribution to stirring and mixing while identifying the hotspots of the phenomenon. Our analysis demonstrates an effective approach for studying regional water mixing and connectivity, which could support coastal management in data-limited regions.
  • Editorial: Advanced modeling and simulation of flow in subsurface reservoirs with fractures and wells for a sustainable industry

    Sun, Shuyu; Edwards, Michael; Frank, Florian; Li, Jingfa; Salama, Amgad; Yu, Bo (Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles, EDP Sciences, 2021-03-26) [Article]
    Flow in subsurface reservoirs is a crucial process in a wide range of applications at different time and space scales, such as petroleum exploration and recovery, groundwater contamination, subsurface carbon sequestration, and geothermal reservoir engineering. As an effective method, modeling and simulation of flow in subsurface reservoirs become essential components of many scientific and engineering applications in recent years. Significant advances have been made in this area, but accurate modeling and efficient, robust simulation still remain a challenging problem, especially for flow and transport in subsurface reservoirs with fractures and wells. To facilitate the exchange and dissemination of original research results and state-of-the-art reviews pertaining to flow in subsurface reservoirs with fractures and wells efficiently, we organized a special issue on “Advanced modeling and simulation of flow in subsurface reservoirs with fractures and wells for a sustainable industry” within Oil & Gas Science and Technology.
  • Short-Range Ordered Iridium Single Atoms Integrated into Cobalt Oxide Spinel Structure for Highly Efficient Electrocatalytic Water Oxidation

    Shan, Jieqiong; Ye, Chao; Chen, Shuangming; Sun, Tulai; Jiao, Yan; Liu, L. M.; Zhu, Chongzhi; Song, Li; Han, Yu; Jaroniec, Mietek; Zhu, Yihan; Zheng, Yao; Qiao, Shi-Zhang (Journal of the American Chemical Society, American Chemical Society (ACS), 2021-03-25) [Article]
    Noble metals manifest themselves with unique electronic structures and irreplaceable activity toward a wide range of catalytic applications but are unfortunately restricted by limited choice of geometric structures spanning single atoms, clusters, nanoparticles, and bulk crystals. Herein, we propose how to overcome this limitation by integrating noble metal atoms into the lattice of transition metal oxides to create a new type of hybrid structure. This study shows that iridium single atoms can be accommodated into the cationic sites of cobalt spinel oxide with short-range order and an identical spatial correlation as the host lattice. The resultant Ir<sub>0.06</sub>Co<sub>2.94</sub>O<sub>4</sub> catalyst exhibits much higher electrocatalytic activity than the parent oxide by 2 orders of magnitude toward the challenging oxygen evolution reaction under acidic conditions. Because of the strong interaction between iridium and cobalt oxide support, the Ir<sub>0.06</sub>Co<sub>2.94</sub>O<sub>4</sub> catalyst shows significantly improved corrosion resistance under acidic conditions and oxidative potentials. This work eliminates the "close-packing" limitation of noble metals and offers promising opportunity to create analogues with desired topologies for various catalytic applications.
  • Perspectives on spintronic diodes

    Finocchio, Giovanni; Tomasello, Riccardo; Fang, Bin; Giordano, Anna; Puliafito, Vito; Carpentieri, Mario; Zeng, Zhongming (arXiv, 2021-03-25) [Preprint]
    Spintronic diodes are emerging as disruptive candidates for impacting several technological applications ranging from the Internet of Things to Artificial Intelligence. In this letter, an overview of the recent achievements on spintronic diodes is briefly presented, underling the major breakthroughs that have led these devices to have the largest sensitivity measured up to date for a diode. For each class of spintronic diodes (passive, active, resonant, non-resonant), we indicate the remaining developments to improve the performances as well as the future directions. We also dedicate the last part of this perspective to new ideas for developing spintronic diodes in multiphysics systems by combining 2-dimensional materials and antiferromagnets.

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