Use Of Structures Research Articles

Routes to high-performance layered oxide cathodes for sodium-ion batteries.

Sodium-ion batteries (SIBs) are experiencing a large-scale renaissance to supplement or replace expensive lithium-ion batteries (LIBs) and low energy density lead-acid batteries in electrical energy storage systems and other applications. In this case, layered oxide materials have become one of the most popular cathode candidates for SIBs because of their low cost and comparatively facile synthesis method. However, the intrinsic shortcomings of layered oxide cathodes, which severely limit their commercialization process, urgently need to be addressed. In this review, inherent challenges associated with layered oxide cathodes for SIBs, such as their irreversible multiphase transition, poor air stability, and low energy density, are systematically summarized and discussed, together with strategies to overcome these dilemmas through bulk phase modulation, surface/interface modification, functional structure manipulation, and cationic and anionic redox optimization. Emphasis is placed on investigating variations in the chemical composition and structural configuration of layered oxide cathodes and how they affect the electrochemical behavior of the cathodes to illustrate how these issues can be addressed. The summary of failure mechanisms and corresponding modification strategies of layered oxide cathodes presented herein provides a valuable reference for scientific and practical issues related to the development of SIBs.

A reconfigurable acoustic coding metasurface for tunable and broadband sound focusing

The targeted concentration of acoustic waves has significant implications for industrial nondestructive testing, ultrasound diagnosis, and medical treatment. Most conventional sound-focusing metasurfaces suffer from an untunable focus, narrow bandwidth, and fixed geometric configurations, which severely constrain their practical utility. In this paper, we propose a reconfigurable acoustic coding metasurface composed of two coding units with high transmittance and transmitted phases of 0 and π for realizing tunable and broadband sound focusing. Through the straightforward manipulation of each unit structure and alterations in the coding sequences, precise control of the focus position across the entire working plane is attainable, enabling both tunable axial-axis and off-axis sound-focusing effects. Moreover, the sound-focusing performance of the proposed metasurface is excellent within a broad frequency range from 3000 to 5500 Hz. The experimental results are consistent with theoretical expectations and numerical simulations. This work lays a practical foundation for the design of acoustic devices for tunable and broadband sound focusing.

Study on the mechanism of hydrodynamic manipulation of floc structure to achieve high-flux of coagulation macro-filtration for the rapid removal of Aphanizomenonflos-aquae

Coagulation-filtration hybrid process has been widely used in algae removal treatment to improve the water quality and alleviate the membrane fouling. However, the intricate interplay of how floc structure induced by coagulation hydraulic shear influences the cake layer and filtration performance in coagulation macro-filtration of microalgae remains unexplored. In this study, a novel coagulation filtration with macro-pore of 75 μm was first adopted for the rapid removal of Aphanizomenonflos-aquae, and the floc structure was artificially manipulated through various velocity gradients to explore the effect mechanism of the coagulation hydrodynamic shear on the macro-filtration performance from the perspectives of floc characteristics (size and fractal dimension) and cake layer structure (thickness and roughness). The results showed that an optimal average flux of 31257.64 ± 2776.28 L·m−2·h−1 can be achieved at a manipulated appropriate velocity gradient (19 s−1), which is 1.1–2.3 times the flux achieved at higher or non-velocity gradients. The flocs formed at low velocity gradient were large and loose, while those formed at high velocity gradient were small and compact. Subsequently, the cake layer stacked by loose flocs was thicker and coarser than that by compact flocs, and exhibited a lower specific cake resistance, yielding a higher average flux. Moreover, a theoretical model for average flux was developed by introducing the velocity gradient, which directly elucidates how hydrodynamic shear affects floc characteristic, cake structure and filtration flux for the coagulation macro-filtration of Aphanizomenonflos-aquae. This study lays a theoretical foundation for the optimization of coagulation macro-filtration performance of microalgae and provides a new solution for the large flux removal of cyanobacteria by artificially regulating the coagulation hydrodynamic shear.

Corrosion Resistant Multilayered Electrode Comprising Ni3N Nanoarray Overcoated with NiFe‐Phytate Complex for Boosted Oxygen Evolution in Seawater Electrolysis

AbstractEngineering high‐performance oxygen evolution reaction (OER) anode material with high activity, selectivity, and strong robustness against chloride corrosion is critical to advance seawater electrolysis for large‐scale production of H2, yet a daunting challenge. Herein it is reported for the first time, the engineer of a multilayered electrode consisting of Ni foam‐supported Ni3N porous nanosheet array decorated with NiFe‐phytate coordination complex overlayer (NF/Ni3N@NiFe‐PA) via a facile interfacial coordination assembly, for remarkably boosted and sustained OER in alkaline seawater electrolysis. Benefitting from regulated electronic state by synergism between Ni and Fe species, boosted proton‐coupled electron transfer via accelerating proton movement with the aid of incorporated phytic acid as proton transfer relay, and promoted mass transfer rendered by unique superhydrophilic and superaerophobic property, the resulting NF/Ni3N@NiFe‐PA demonstrates prominent OER activity in seawater. Impressively, integrating anticorrosive Ni3N with NiFe‐PA complex and in situ generated NiFeOOH can collaboratively contribute to chloride repelling, leading to exceptional corrosion resistance of the electrode. This work affords a novel paradigm to engineer active and corrosion‐resistive anode for selective OER in saline water electrolysis via simultaneous geometric and electronic structural manipulation.

MARS Plus: An Improved Molecular Design Tool for Complex Compounds Involving Ionic, Stereo, and Cis-Trans Isomeric Structures.

MARS (Molecular Assembling and Representation Suite) (Hsu et al. J. Chem. Inf. Model. 2019, 59, 3703-3713) is a toolbox for the molecular design of organic molecules. MARS uses integer arrays to represent the elements and connectivity between elements of a molecule. It provides a collection of operations to manipulate the elemental composition and connectivity of a molecule (or a pair of molecules), enabling the creation of novel chemical compounds. In this work, the original MARS is extended to handle complex molecular structures, including geometric (cis-trans) isomers, stereo isomers, cyclic compounds, and ionic species. The extended version of MARS, referred to as MARS+, has a more comprehensive coverage of the chemical space and therefore can explore molecules with a greater chemical and physical diversity. Compared to other molecular design tools, MARS+ is designed to perform all possible manipulations on a given molecule or a pair of molecules. Molecular structure manipulation can be conducted in either a controlled or a random fashion. Furthermore, every structure manipulation has a counterpart so that the operation can be reversed. Nearly any possible chemical structure can be generated with MARS+ via a combination of molecular operations. The capabilities of MARS+ are examined by the design of new ionic liquids (ILs). The results show that MARS+ is a useful tool for computer-aided molecular design (CAMD) and molecular structure enumeration.

Ultrafine design of carbon whisker array @ hollow carbon sphere anode for superior K-storage

Even though bottom-up strategy has been successfully developed to construct nanocarbon materials from molecule blocks for energy storage applications, elaborate structure manipulation via a facile and scalable method remains a big challenge. Herein, a facile free-radical C–C coupling-based bottom-up strategy was proposed to controllably construct carbon whisker array @ hollow carbon sphere (CWA@HCS) anode from the molecule block of hexabromobenzene (HBB) for superior K-storage. The novel CWA@HCS anode was easily achieved via the controllable catalysis of C–C coupling reaction on the surface of commercial metallic Cu particles. The optimized CWA@HCS anode delivered a high reversible K-storage capacity of 367.6 mAh/g at 50 mA/g, excellent rate capability (155.5 mAh/g at 1000 mA/g), and excellent long-term cycle performance (182.5 mAh/g maintained after 700 cycles at 500 mA/g). In addition, the full cell assembled from CWA@HCS electrode showed excellent cycle performance and rate performance. These excellent K-storage properties should be attributed to the surface capacitive-dominated K-storage mechanism guaranteed by the three-dimensional (3D) array structure. This study provides a basic reference for the design of advanced nanocarbon materials as well as anode materials for potassium ion batteries.

Simultaneous Morphology and Band Structure Manipulation of BiOBr by Te Doping for Enhanced Photocatalytic Oxygen Evolution.

The photocatalytic oxygen evolution of bismuth oxybromide (BiOBr) is greatly hindered by its low visible-light response and high electron-hole recombination. Nonmetal doping can effectively alleviate these issues, leading to improvement in photocatalytic performance. Herein, Bi2Te3 was introduced as both the Te doping source and the morphology-control template to improve the photocatalytic performance of BiOBr. Appropriate amounts of Te are critical to maintain the ultrathin plate-like structure of BiOBr, whereas excessive Te results in the formation of a flower-like architecture. Oxygen evolution activity disclosed that a plate-like structure is essential for realizing higher performance owing to sufficient light utilization and efficient charge separation. An optimal oxygen evolution rate of 368.0 μmol h-1 g-1 was achieved for the Te-doped sample, which is 2.3-fold as that of the undoped BiOBr (158.9 μmol h-1 g-1). Theoretical calculations demonstrated that Te doping can induce impurity levels above the valence band of BiOBr, which slightly narrowed the band gap and strengthened the light absorption in the range of 400-800 nm. More importantly, Te dopants could act as shallow traps for confining the excited electrons, thus prolonging the carrier lifetime. This work provides a novel strategy to prepare highly efficient photocatalysts by simultaneously realizing morphology manipulation and nonmetal doping.

Characterization of electronic structure, magnetism, and electric field manipulation in non-metal doped monolayer 1T-HfS2

We have explored the influence of low-concentration doping with various non-metallic elements on the chemical bonding characteristics, electronic structure, and magnetism of monolayer 1T-HfS2 using the first-principles method based on density functional theory. The investigations revealed that the formation energy of the doping systems is influenced by the atomic number of the dopant atoms, diminishing as dopant atoms move further away from S in the periodic table. The hybridization between dopant atoms and neighboring Hf atoms resulted in spin splitting near the Fermi level, leading to the emergence of magnetism in the B and C doping systems. Furthermore, the introduction of an externally applied weak electric field, while not altering the fundamental characteristics of the system, allowed for fine-tuning of the band gap and magnetism. This study has revealed the impact of different types of doping atoms and external weak electric fields on the electronic properties of monolayer 1T-HfS2 material.

Electronic structure and magnetic properties of CrI3 monolayer doped by rare earth metal atoms

CrI3 monolayer is a two-dimensional (2D) ferromagnetic (FM) semiconductor materials with broad application prospects in the field of spintronics due to its magnetic semiconductor feature and unique 2D structure. In this work, we employ first-principles calculations based on density functional theory to investigate the electronic structure and magnetic properties of CrI3 monolayer doped with rare earth (RE) metal atoms (RE = Sc, Y, La, Ce, Pr, Nd, Pm, Eu, Gd, Tm, and Lu). The results demonstrate that doping with RE atoms enables the control of total magnetic moments and a significantly enhancement of the Curie temperature of CrI3 monolayer. Especially, the Curie temperature of CrGdI6 monolayer reaches 347.58 K, which could be a promising candidate for realizing room temperature ferromagnetism. Furthermore, by applying strain and electric field, the CrREI6 monolayers exhibit metal, half-metal and spin gapless semiconductor properties. These findings not only provide valuable insights into the manipulation of electronic structure and magnetic properties in CrI3 monolayer but also establish RE doped CrI3 monolayer as a promising material for spintronic devices.

Modulated high-order Hermite-Gaussian beams with uniform intensity distribution

Hermite-Gaussian beams have been studied since the early years of laser modes. With the recent development of structured light, different modulation methods have been demonstrated to control the energy, polarization and propagation behavior of Hermite-Gaussian beams. In this work we introduce an inverse design approach to modulate the energy distribution among different lobes of Hermite-Gaussian beams. In this approach, the desired intensity profiles of Hermite-Gaussian beams are the starting point. The required spatial phase masks are calculated through inverse Fourier transform, then projected on a spatial light modulator to convert conventional Gaussian beams into modulated Hermite-Gaussian beams. The experimental modulated high-order (m = 10, n = 10) Hermite-Gaussian beams show much improved energy distribution among different lobes over standard Hermite-Gaussian beams. These modulated Hermite-Gaussian beams also have improved beam quality factor M2 after modulation. These results demonstrated the feasibility to fine-tune the intensity profiles of Hermite-Gaussian beams, which have applications in structured illumination, particle manipulation and optical communications.

Optimization of the Digital Workflow for Obtaining Dental Rehabilitation Devices Obtained by the Cone Beam and 3D Printing

Digital workflow in dentistry is an innovation technique that has made great progress in recent years that provides personalized patient care incorporating CAD/CAM technology (Computed Assisted Design/Computed Assisted Manufacturing) for the visualization and digital manipulation of structures obtained from CBCT (Cone Beam Computed Tomography) or intraoral scanner. This allows to build structures that can help the dentist in treating patients in a personalized way. The digital flow process mainly consists of three pillars: image acquisition, visualization and manipulation of three-dimensional models and 3D printing. This clinical methodology can be used in all fields of dentistry, where the design of anatomical posts to replace the use of conventional fiberglass poles stands out. The above allows to a predictable dynamic of treatment which influences the decrease of risk of fracture due to overload of chewing forces. The digital flow is improved with the integration of bioengineering, the technological and biological knowledge of this discipline allows increasing the effectiveness and efficiency of the process to obtain better results.

Photochromic Nucleosides and Oligonucleotides.

Photochromism is a reversible phenomenon wherein a material undergoes a change in color upon exposure to light. In organic photochromes, this effect often results from light-induced isomerization reactions, leading to alterations in either the spatial orientation or electronic properties of the photochrome. The incorporation of photochromic moieties into biomolecules, such as proteins or nucleic acids, has become a prevalent approach to render these biomolecules responsive to light stimuli. Utilizing light as a trigger for the manipulation of biomolecular structure and function offers numerous advantages compared to other stimuli, such as chemical or electrical treatments, due to its non-invasive nature. Consequently, light proves particularly advantageous in cellular and tissue applications. In this review, we emphasize recent advancements in the field of photochromic nucleosides and oligonucleotides. We provide an overview of the design principles of different classes of photochromes, synthetic strategies, critical analytical challenges, as well as structure-property relationships. The applications of photochromic nucleic acid derivatives encompass diverse domains, ranging from the precise photoregulation of gene expression to the controlled modulation of the three-dimensional structures of oligonucleotides and the development of DNA-based fluorescence modulators. Moreover, we present a future perspective on potential modifications and applications.

Bioinspired Asymmetric Polypyrrole Membranes with Enhanced Photothermal Conversion for Highly Efficient Solar Evaporation.

Solar-driven interfacial evaporation (SDIE) has attracted great attention by offering a zero-carbon-emission solution for clean water production. The manipulation of the surface structure of the evaporator markedly promotes the enhancement of light capture and the improvement of evaporation performance. Herein, inspired by seedless lotus pod, a flexible pristine polypyrrole (PPy) membrane with macro/micro-bubble and nanotube asymmetric structure is fabricated through template-assisted interfacial polymerization. The macro- and micro-hierarchical structure of the open bubbles enable multiple reflections inner and among the bubble cavities for enhanced light trapping and omnidirectional photothermal conversion. In addition, the multilevel structure (macro/micro/nano) of the asymmetric PPy (PPy-A) membrane induces water evaporation in the form of clusters, leading to a reduction of water evaporation enthalpy. The PPy-A membranes achieve a full-spectrum light absorption of 96.3% and high evaporation rate of 2.03kgm-2 h-1 under 1 sun. Long-term stable desalination is also verified with PPy-A membranes by applying one-way water channel. This study demonstrates the feasibility of pristine PPy membranes in SDIE applications, providing guidelines for modulation of the evaporator topologies toward high-efficient solar evaporation.

Effects of Endoscopic Sinus Surgery on Olfactory Function.

To review the effects of endoscopic sinus surgery and endonasal approaches to the skull base on olfaction. Advancements in endonasal endoscopic approaches to the sinuses and skull base allow for direct treatment of a variety of sinonasal and skull base diseases. However, these extended approaches will often require manipulation of normal anatomical structures and the olfactory neuroepithelium. Depending on the planned procedure and extent of disease, the prognosis of olfactory perception can vary significantly among patients. Endoscopic sinonasal surgical procedures may impact olfaction. Optimizing olfactory function requires proper surgical techniques, gentle handling of tissue, and perioperative care. Surgeons must discuss objectives and manage patient expectations. Routine olfactory assessment is crucial in surgical work-up and follow-up. Preserving anatomical structures while addressing the obstruction of the olfactory cleft helps to prevent decreased olfactory threshold. However, smell identification and discrimination do not always correlate with sinonasal anatomy.

Metacognition and diagrams in marking-for-self

AbstractMetacognition relies on representations, which are commonly viewed as internal knowledge structures. We explore the idea that external embodied diagrams, rather than monomodal symbolic-based entities, can provide an accurate description of metacognition in choreographic dance. When marking, dancers use their bodies to represent properties, dynamics, or structures of dance phrases. Marking-for-self occurs when a dancer marks the dance in their own unique manner, potentially allowing for real-time reflection through the manipulation of external signs. These manipulations can be considered diagrammatic semiosis, as diagrams signify shared relational parts analogous to the parts of their objects. Based on Peirce’s semiotics, we argue that semiosis is crucial for metacognition. This paper is structured to first review marking and marking-for-self, followed by an overview of metacognition. We then define marking-for-self as a metacognitive phenomenon and introduce Peirce’s concept of semiosis and diagrams. Finally, we describe marking as a diagrammatic sign and explain how marking-for-self is an embodied metacognitive process achieved through the manipulation of diagrammatic structures.

A Patching and Coding Lipid Raft-Localized Universal Imaging Platform.

Lipid rafts (LRs) are relatively well-ordered functional microdomains in cell membranes and play an irreplaceable role in physiological processes as a transduction platform for multiple signaling pathways. Due to their small size and high spatiotemporal dynamics, it is difficult to perform lipid raft-localized biomolecule imaging on the surface of living cells. Here, we report a DNA nanotechnology-based platform for reversible manipulation and localized analysis of lipid rafts, which consists of two modules: "patching and coding probe pair" and "fishing probe". The probe pair is generated by modifying two different sets of connectable DNA structures on a lipid raft-specific protein. After recognizing lipid rafts, the two probes in close proximity are linked by a DNA ligase reaction to form a lipid raft identity (LR-ID) code. The LR-ID strand patches and stabilizes the lipid raft structure. Interestingly, the raft patches formed can be depatched by restriction endonucleases, providing the first reversible manipulation of the lipid raft structure in living cells. We also designed a "fishing probe" with a DNA hairpin structure using an aptamer that can specifically bind to the target. The probe can cascade the reaction to two input signals "LR-ID" and "target protein" to generate an "off-on" fluorescence switch, allowing imaging and dynamic monitoring of target proteins localized in lipid rafts. By encoding arbitrary targets (in the case of glycans) in lipid rafts, we have created a universal lipid raft-localized imaging platform. This work provides an integrated analytical and manipulative platform to reveal lipid rafts and associated signaling pathways at the molecular level.

Manipulation of Chemical and Crystal Structures of Multilayered Copper-Hexaaminobenzene Coordination Nanosheets to Modulate Conductivity with Precise Control of Liquid–Liquid Interfacial Synthesis

Multilayered coordination nanosheets made of copper ions and hexaaminobenzene (CuHAB) were synthesized in a liquid–liquid interfacial reaction in the presence of a base and an oxidizing agent. X-ray diffraction studies revealed the suitability of an oxidizing agent with a low oxidation potential for the synthesis of highly crystalline CuHAB. The base concentration affects the chemical and crystal structures of CuHAB. The nanosheets synthesized at low base concentrations exhibit humidity-responsive conductivity due to the ligating amino group. Meanwhile, the nanosheets prepared at high base concentrations have different stacking structures from the CuHABs formed at low base concentrations and show greater conductivity. These results indicate that the liquid–liquid interfacial synthesis with an appropriate oxidizing agent and quantitative addition of base can modulate chemical and stacking structures of coordination nanosheets composed of hexaaminobenzene ligand and their functionalities.

Chlorine doping endows Bi2Te3 with superior charge storage properties as a cathode material for high-performance aqueous zinc-proton hybrid ion batteries

To enhance the performance of aqueous batteries, researchers have introduced bismuth chalcogenides as cathode materials in zinc-based batteries. However, their ability to store charge is hindered by low electronic conductivity and poor ion adsorption capability. In this study, we fabricated Cl-doped Bi2Te3 (CBT) sheets through the hydrothermal tellurization of BiOCl plates. Density functional theory (DFT) calculations showed that CBT exhibits conductor-like electrical properties due to electronic structure manipulation. More importantly, the ion adsorption capability of CBT sheets was improved with the introduction of Cl dopant. Consequently, the CBT cathode demonstrated impressive rate capability, achieving a high capacity of 305 mA h g−1 at 0.2 A g−1, and sustaining a capacity of 124.7 mA h g−1 at 30 A g−1. Furthermore, after over 10,000 cycles at 20 A g−1, the reversible capacity remained at 115.8 mA h g−1, demonstrating exceptional cyclic stability.

Bio-Inspired Supramolecular Self-Assembled Carbon Nitride Nanostructures for Photocatalytic Water Splitting.

Fast production of hydrogen and oxygen in large amounts at an economic rate is the need of the hour to cater to the needs of the most awaited hydrogen energy, a futuristic renewable energy solution. Production of hydrogen through simple water splitting via visible light photocatalytic approach using sunlight is considered as one of the most promising and sustainable approaches for generating clean fuels. For this purpose, a variety of catalytic techniques and novel catalysts have been investigated. Among these catalysts, carbon nitride is presently deemed as one of the best candidates for the visible light photocatalysis due to its unique molecular structure and adequate visible-range bandgap. Its bandgap can be further engineered by structural and morphological manipulation or by doping/hybridization. Among numerous synthetic approaches for carbon nitrides, supramolecular self-assembly is one of the recently developed elegant bottom-up strategies as it is bio-inspired and provides a facile and eco-friendly route to synthesize high surface area carbon nitride with superior morphological features and other semiconducting and catalytic properties. The current review article broadly covers supramolecular self-assembly synthesis of carbon nitride nanostructures and their photocatalytic water-splitting applications and provides a comprehensive outlook on future directions.

Ecological function and interaction of different bacterial groups during alginate processing in coastal seawater community

The degradation of high molecular weight organic matter (HMWOM) is a core process of oceanic carbon cycle, which is determined by the activity of microbial communities harboring hundreds of different species. Illustrating the active microbes and their interactions during HMWOM processing can provide key information for revealing the relationship between community composition and its ecological functions. In this study, the genomic and transcriptional responses of microbial communities to the availability of alginate, an abundant HMWOM in coastal ecosystem, were elucidated. The main degraders transcribing alginate lyase (Aly) genes came from genera Alteromonas, Psychrosphaera and Colwellia. Meanwhile, some strains, mainly from the Rhodobacteraceae family, did not transcribe Aly gene but could utilize monosaccharides to grow. The co-culture experiment showed that the activity of Aly-producing strain could promote the growth of Aly-non-producing strain when alginate was the sole carbon source. Interestingly, this interaction did not reduce the alginate degradation rate, possibly due to the easily degradable nature of alginate. This study can improve our understanding of the relationship between microbial community activity and alginate metabolism function as well as further manipulation of microbial community structure for alginate processing.