Nanosheet-Assembled MnO2-Integrated Electrode Based on the Low-Temperature and Green Chemical Route

The development of superior electrochemical energy-storage devices designed through a facile, cost-efficient, and green synthesis technique is the key to addressing the intermittent nature of renewable energy sources such as solar and wind energy. In our present work, we design a simple, surfactant-free, and low-temperature chemical strategy to prepare novel integrated, MnO2 composite electrodes with two-dimensional (2D) nanosheet film directly supported on three-dimensional (3D) conductive nickel foam. Benefiting from the specific 2D nanosheet architecture to provide a large interfacial contact area and highly conductive metal scaffolds to facilitate fast electron transfer, the novel nanosheet-assembled MnO2-integrated electrodes exhibit higher specific capacitance of 446 F g−1 at the current density of 1 A g−1 compared with nanostructured MnO2 and commercial MnO2 powder electrodes. More importantly, the as-synthesized devices are able to achieve an outstanding cycling performance of 95% retention after 3000 cycles. The present work, which is based on the low-temperature chemical route to deposit active materials on the conductive substrate, provides new insights into designing a binder-free supercapacitor system to improve the specific capacitance, cycling, and rate performance as next-generation, energy-storage devices.

The Synthesis and Characterization of a Novel One-Dimensional Bismuth (III) Coordination Polymer as a Precursor for the Production of Bismuth (III) Oxide Nanorods

A novel Bi (III) coordination compound, [Bi(HQ)(Cl)4]n ((Q = pyridine-4-carbaldehyde thiosemicarbazone), was prepared in this research using a sonochemical technique. SEM, infrared spectroscopy (IR), XRD, and single-crystal X-ray analysis were utilized to analyze the Bi(III) coordination compound. The structure determined using single-crystal X-ray crystallography indicates that the coordination compound is a 1D polymer in solid state and that the coordination number of bismuth (III) ions is six, (BiSCl5), with one S donor from the organic ligand and five Cl donors from anions. It is equipped with a hemidirectional coordination sphere. It is interesting that the ligand has been protonated in the course of the reaction with a Cl- ion balancing the charge. This compound’s supramolecular properties are directed and regulated by weak directional intermolecular interactions. Through π–π stacking interactions, the chains interact with one another, forming a 3D framework. Thermolysis of the compound at 170 °C with oleic acid resulted in the formation of pure phase nanosized Bi (III) oxide. SEM technique was used to examine the morphology and size of the bismuth (III) oxide product produced.

π-Hole Tetrel Bonds—Lewis Acid Properties of Metallylenes

The MP2/aug-cc-pVTZ calculations were performed on the dihalometallylenes to indicate their Lewis acid and Lewis base sites. The results of the Cambridge Structural Database search show corresponding and related crystal structures where the tetrel center often possesses the configuration of a trigonal bipyramid or octahedron. The calculations were also carried out on dimers of dichlorogermylene and dibromogermylene and on complexes of these germylenes with one and two 1,4-dioxide molecules. The Ge⋯Cl, Ge⋯Br, and Ge⋯O interactions are analyzed. The Ge⋯O interactions in the above mentioned germylene complexes may be classified as the π-hole tetrel bonds. The MP2 calculations are supported by the results of the Quantum Theory of Atoms in Molecules (QTAIM) and the Natural Bond Orbital (NBO) approaches.

Secondary Structure and X-ray Crystallographic Analysis of the Glideosome-Associated Connector (GAC) from Toxoplasma gondii

A model for parasitic motility has been proposed in which parasite filamentous actin (F-actin) is attached to surface adhesins by a large component of the glideosome, known as the glideosome-associated connector protein (GAC). This large 286 kDa protein interacts at the cytoplasmic face of the plasma membrane with the phosphatidic acid-enriched inner leaflet and cytosolic tails of surface adhesins to connect them to the parasite actomyosin system. GAC is observed initially to the conoid at the apical pole and re-localised with the glideosome to the basal pole in gliding parasite. GAC presumably functions in force transmission to surface adhesins in the plasma membrane and not in force generation. Proper connection between F-actin and the adhesins is as important for motility and invasion as motor operation itself. This notion highlights the need for new structural information on GAC interactions, which has eluded the field since its discovery. We have obtained crystals that diffracted to 2.6–2.9 Å for full-length GAC from Toxoplasma gondii in native and selenomethionine-labelled forms. These crystals belong to space group P212121; cell dimensions are roughly a = 119 Å, b = 123 Å, c = 221 Å, α = 90°, β = 90° and γ = 90° with 1 molecule per asymmetric unit, suggesting a more compact conformation than previously proposed

Optical Properties of InGaN/GaN QW with the Same Well-Plus-Barrier Thickness

Optical properties of wurtzite violet InGaN/GaN quantum well (QW) structures, with the same well-plus-barrier thickness, grown by metal-organic chemical vapor deposition (MOCVD) on c-plane sapphire substrates, were investigated using temperature-dependent photoluminescence (TDPL) and excitation-power-dependent photoluminescence (PDPL). Two samples were compared: one had a thicker well (InGaN/GaN 3/5 nm); the other had a thicker barrier (InGaN/GaN 2/6 nm). It was found that the GaN barrier thickness in the InGaN/GaN MQWs plays an important role in determining the optical characteristics of the MQWs. The peak energy of the two samples varied with temperature in an S-shape. The thicker-barrier sample had a higher turning point from blueshift to redshift, indicating a stronger localization effect. From the Arrhenius plot of the normalized integrated PL intensity, it was found that the activation energy of the nonradiative process also increased with a thicker barrier thickness. The radiation recombination process was dominated in the sample of the thicker barrier, while the non-radiation process cannot be negligible in the sample of the thicker well.

Variation of Surface Nanostructures on (100) PbS Single Crystals during Argon Plasma Treatment

The nanostructuring of the (100) PbS single crystal surface was studied under varying argon plasma treatment conditions. The initial PbS single crystals were grown by high-pressure vertical zone melting, cut into wafer samples, and polished. Subsequently, the PbS single crystals were treated with inductively coupled argon plasma under varying treatment parameters such as ion energy and sputtering time. Plasma treatment with ions at a minimum energy of 25 eV resulted in the formation of nanotips with heights of 30–50 nm. When the ion energy was increased to 75–200 eV, two types of structures formed on the surface: high submicron cones and arrays of nanostructures with various shapes. In particular, the 120 s plasma treatment formed specific cruciform nanostructures with lateral orthogonal elements oriented in four <100> directions. In contrast, plasma treatment with an ion energy of 75 eV for 180 s led to the formation of submicron quasi-spherical lead structures with diameters of 250–600 nm. The nanostructuring mechanisms included a surface micromasking mechanism with lead formation and the vapor–liquid–solid mechanism, with liquid lead droplets acting as self-forming micromasks and growth catalysts depending on the plasma treatment conditions (sputtering time and rate).

Spectroscopic and Surface Crystallization Characterizations of Yttrium-Doped Phosphate Glasses

The composition, structure, and thermal behaviors of yttrium-containing phosphate glasses were studied in this work, and the glass-ceramics were prepared via the two-step crystallization method. The XRD and SEM-EDS results show the forming range of the phosphate glass system and the formation of YPO4 (xenotime) due to the addition of excessive Y2O3. The spectroscopic characterization of these glasses presented shifts of the infrared and Raman bands, demonstrating the depolymerization of the glass network and the formation of novel P–O–Y bonds, and the deconvoluted Raman spectra also exhibited the occurrence of the disproportionation reaction in the glass melting process. The content of non-bridging oxygen (NBOs) from the UV–vis spectra first increased and then decreased with increasing Y2O3. The thermal behaviors show that the Y2O3 reduced the crystallization peak temperature and the thermal stability of the glasses. The crystalline behaviors of the phosphate glass matrix were investigated at different crystallization times of 2–10 h, and a transformation of the crystallization mechanism from surface to volume crystallization was found. The yttrium phosphate glass-ceramics crystallized for 10 h exhibited transformation of the main crystalline phases with increasing Y2O3, and the grain-oriented crystalline surface became irregular.

Study on the Formation of Reactive Material Shaped Charge Jet by Trans-Scale Discretization Method

The formation process of reactive materials shaped charge is investigated by X-ray photographs and numerical simulation. In order to study the formation process, a trans-scale discretization method is proposed. A two-dimensional finite element model of shaped charge and reactive material liner is established and the jet formation process, granule size difference induced particle dispersion and granule distribution induced jet particle distribution are analyzed based on Autodyn-2D platform and Euler solver. The result shows that, under shock loading of shaped charge, the Al particle content decreases from the end to the tip of the jet, and increases as the particle size decreases. Besides, the quantity of Al particles at the bottom part of the liner has more prominent influence on the jet head density than that in the other parts, and the Al particle content in the high-speed section of jet shows inversely proportional relationship to the ratio of the particle quantity in the top area to that in the bottom area of liner.

Multiscale Modelling and Characterization of Mechanical Properties in Heat-Resistant Alloys

Various heat-resistant alloys have been used in industry; however, the bridge between the bulk mechanical properties and the underlying micro- and nanoscopic local properties remains an issue [...]

Cellulose Nanomaterials as a Future, Sustainable and Renewable Material

Cellulose nanomaterials (CNs) are renewable, bio-derived materials that can address not only technological challenges but also social impacts. This ability results from their unique properties, for example, high mechanical strength, high degree of crystallinity, biodegradable, tunable shape, size, and functional surface chemistry. This minireview provides chemical and physical features of cellulose nanomaterials and recent developments as an adsorbent and an antimicrobial material generated from bio-renewable sources.