Construction of point-line-plane (0-1-2 dimensional) Fe<Subscript>2</Subscript>O<Subscript>3</Subscript>-SnO<Subscript>2</Subscript>/graphene hybrids as the anodes with excellent lithium storage capability

The assembly of hybrid nanomaterials has opened up a new direction for the construction of high-performance anodes for lithium-ion batteries (LIBs). In this work, we present a straightforward, eco-friendly, one-step hydrothermal protocol for the synthesis of a new type of Fe₂O₃-SnO₂/graphene hybrid, in which zero-dimensional (0D) SnO₂ nanoparticles with an average diameter of 8 nm and one-dimensional (1D) Fe₂O₃ nanorods with a length of ~150 nm are homogeneously attached onto two-dimensional (2D) reduced graphene oxide nanosheets, generating a unique point-line-plane (0D-1D-2D) architecture. The achieved Fe₂O₃-SnO₂/graphene exhibits a well-defined morphology, a uniform size, and good monodispersity. As anode materials for LIBs, the hybrids exhibit a remarkable reversible capacity of 1,530 mA·g^?1 at a current density of 100 mA·g^?1 after 200 cycles, as well as a high rate capability of 615 mAh·g^?1 at 2,000 mA·g^?1. Detailed characterizations reveal that the superior lithium-storage capacity and good cycle stability of the hybrids arise from their peculiar hybrid nanostructure and conductive graphene matrix, as well as the synergistic interaction among the components.

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Interface evolution in the platelet-like SiC@C and SiC@SiO<Subscript>2</Subscript> monocrystal nanocapsules

Carbon-coated SiC@C nanocapsules (NCs) with a hexagonal platelet-like morphology were fabricated by a simple direct current (DC) arc-discharge plasma method.The SiC@C NCs were monocrystalline,120-150 nm in size,and approximately 50 nm thick.The formation of the as-prepared SiC@C NCs included nucleation of truncated octahedral SiC seeds and subsequent anisotropic growth of the seeds into hexagonal nanoplatelets in a carbon-rich atmosphere.The disordered carbon layers on the SiC@C NCs were converted into SiO2 shells of SiC@SiO2 NCs by heat treatment at 650 ℃ in air,during which the shape and inherent characteristics of the crystalline SiC core were obtained.The interface evolution from carbon to SiO2 shells endowed the SiC@SiO2 NCs with enhanced photocatalytic activity due to the hydrophilic and transparent nature of the SiO2 shell,as well as to the photosensitive SiC nanocrystals.The band gap of the nanostructured SiC core was determined to be 2.70 eV.The SiC@SiO2 NCs degraded approximately 95％ of methylene blue in 160 min under visible light irradiation.     

Improving the structural stability of Li-rich cathode materials via reservation of cations in the Li-slab for Li-ion batteries

High-capacity Li-rich cathode materials can significantly improve the energy density of lithium-ion batteries, which is the key limitation to miniaturization of electronic devices and further improvement of electrical-vehicle mileage. However, severe voltage decay hinders the further commercialization of these materials. Insights into the relationship between the inherent structural stability and external appearance of the voltage decay in high-energy Li-rich cathode materials are critical to solve this problem. Here, we demonstrate that structural evolution can be significantly inhibited by the intentional introduction of certain adventive cations (such as Ni²⁺) or by premeditated reservation of some of the original Li⁺ ions in the Li slab in the delithiated state. The voltage decay of Li-rich cathode materials over 100 cycles decreased from 500 to 90 or 40 mV upon introducing Ni²⁺ or retaining some Li⁺ ions in the Li slab, respectively. The cations in the Li slab can serve as stabilizers to reduce the repulsion between the two neighboring oxygen layers, leading to improved thermodynamic stability. Meanwhile, the cations also suppress transition metal ion migration into the Li slab, thereby inhibiting structural evolution and mitigating voltage decay. These findings provide insights into the origin of voltage decay in Li-rich cathode materials and set new guidelines for designing these materials for high-energy-density Li-ion batteries.

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Electrochemical capacitance of nanostructured ruthenium-doped tin oxide Sn<Subscript>1–<Emphasis Type="Italic">x</Emphasis></Subscript>Ru<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>O<Subscript>2</Subscript> by the microemulsion method

Synthesis of nanostructured Ru-doped SnO₂ was successfully carried out using the reverse microemulsion method. The phase purity and the crystallite size were analyzed by XRD. The surface morphology and the microstructure of synthesized nanoparticles were analyzed by SEM and TEM. The vibration mode of nanoparticles was investigated using FTIR and Raman studies. The electrochemical behavior of the Ru-doped SnO₂ electrode was evaluated in a 0.1 mol/L Na₂SO₄ solution using cyclic voltammetry. The 5% Ru-doped SnO₂ electrode exhibited a high specific capacitance of 535.6 F/g at a scan rate 20 mV/s, possessing good conductivity as well as the electrocycling stability. The Ru-doped SnO₂ composite shows excellent electrochemical properties, suggesting that this composite is a promising material for supercapacitors.     

Photocatalytic mechanism of high-activity anatase TiO<Subscript>2</Subscript> with exposed (001) facets from molecular-atomic scale: HRTEM and Raman studies

Anatase TiO₂ with a variant percentage of exposed (001) facets was prepared under hydrothermal processes by adjusting the volume of HF, and the photocatalytic mechanism was studied from atomic-molecular scale by HRTEM and Raman spectroscopy. It was revealed that: 1) From HRTEM observations, the surface of original TiO₂ with exposed (001) facets was clean without impurity, and the crystal lattice was clear and completed; however, when mixed with methylene blue (MB) solution, there were many 1 nm molecular absorbed at the surface of TiO₂; after the photocatalytic experiment, MB molecules disappeared and the TiO₂ lattice image became fuzzy. 2) The broken path of the MB chemical bond was obtained by Raman spectroscopy, i.e., after the irradiation of the light, the vibrational mode of C-N-C disappeared due to the chemical bond breakage, and the groups containing C-N bond and carbon rings were gradually decomposed. Accordingly, we propose that the driving force for breaking the chemical bond and the disappearance of groups is from the surface lattice distortion of TiO₂ during photocatalyzation.     

Microstructure evolution and thermoelectric properties of Te-poor and Te-rich (Bi,Sb)<Subscript>2</Subscript>Te<Subscript>3</Subscript> prepared via solidification

This paper explores in detail, the microstructures and thermoelectric properties of Te-rich and Te-poor (Bi,Sb)₂Te₃ alloys. We show that tuning the composition of ternary Bi–Sb–Te type alloys allows us to synthesize a range of microstructures containing a primary solid solution of (Bi,Sb)₂Te₃ with varying amounts of Te solid solution or a (Bi,Sb)Te compound. Te exists as a constituent of the multilayer domain while (Bi,Sb)Te appears in the thin intercellular regions of the (Bi,Sb)₂Te₃ dendritic cells. The presence of Te imparts an n-type behavior to the composite while the (Bi,Sb)₂Te₃ with a small amount of (Bi,Sb)Te exhibits p-type properties. A maximum ZT value of ≈0.4 at 425 K was achieved, opening up the possibility of using these alloys for thermoelectric device applications.     

Characterization of weld seam properties of extruded magnesium hollow profiles

Extrusions of hollow profiles with weld seams were conducted using the magnesium alloy ME21 applying various extrusion ratios. Subsequent analysis of the profiles’ microstructure was performed comparing weld free with weld seam containing material using (polarized) light optical microscopy (LOM). Additionally, the local texture and microstructure in the weld-free material as well as in the weld seam region has been examined with a scanning electron microscope coupled with electron backscatter diffraction technique (SEM-EBSD). The weld-free material and the weld seam are characterized by recrystallized microstructures, whereas few residual cast grains were identified. The local texture distinctively changes from the weld-free material to the weld seam. The texture of the weld-free material is comparable with the typical ME21 sheet texture. In the weld seam area, a pole density is found, which is distributed towards the transverse direction (TD) combined with a split and broadening of the pole density in the extrusion direction (ED). This texture influences the mechanical anisotropy due to the dependence of the activation of basal 〈a〉-slip and \( \{ 10\bar{1}2\} \;\langle 10\bar{1}1\rangle \)-extension twinning on the loading direction in favorably oriented grains.     

Wissen auf losen Blättern im Kontext starrer Theorien

At the end of the nineteenth century, after twelve years of intensive research, the ophthalmologist Theodor Leber (1840–1917) established the chemotaxis of leukocytes as part of inflammation research. Although at the time his theory was smoothly enlisted into immunological research, up until now his name has been connected to chemotaxis only in the English-language literature. Leber was able to use his experimental system to develop a theory of the chemical attraction of the leukocytes during inflammation processes by the beginning of the 1880s, but his unconventional methodology—introducing chemically neutral contaminants in order to trigger inflammation in the eyes of rabbits—contradicted the basic bacteriological Denkstil (style of thought) of inflammation research at the time. Leber held fast to his research practice, which consisted of closely interlocking experimental and theoretical work. Only when an opening appeared in the bacteriological Denkstil was Leber able to transform his experimental observations, written on loose sheets of paper, into convincing evidence for his theory of inflammation. This micro-historical reconstruction of Leber’s experimental and written work, based on his original lab protocols, opens up the research practice of a scientist who was not recognized by the established microbiological inflammation research of the time. Moreover, persistent factors in the generation of knowledge are revealed by connecting this micro-historical reconstruction with a macro-history analysis. Indeed Leber developed his specific paper technology in order to mobilise and stabilise the scientific findings gained through experiment because of the persistence of the bacteriological Denkstil.     

Measurement Uncertainty Budget of the PMV Thermal Comfort Equation

Fanger’s predicted mean vote (PMV) equation is the result of the combined quantitative effects of the air temperature, mean radiant temperature, air velocity, humidity activity level and clothing thermal resistance. PMV is a mathematical model of thermal comfort which was developed by Fanger. The uncertainty budget of the PMV equation was developed according to GUM in this study. An example is given for the uncertainty model of PMV in the exemplification section of the study. Sensitivity coefficients were derived from the PMV equation. Uncertainty budgets can be seen in the tables. A mathematical model of the sensitivity coefficients of \(T_{\mathrm{a}}\), \(h_{\mathrm{c}}\), \(T_{\mathrm{mrt}}\), \(T_{\mathrm{cl}}\), and \(P_{\mathrm{a}}\) is given in this study. And the uncertainty budgets for \(h_{\mathrm{c}}\), \(T_{\mathrm{cl}}\), and \(P_{\mathrm{a}}\) are given in this study.     

Mechanical and Thermophysical Properties of Cerium Monopnictides

The ultrasonic attenuation due to phonon–phonon interaction, thermoelastic relaxation and dislocation damping mechanisms has been investigated in cerium monopnictides CeX (X: N, P, As, Sb and Bi) for longitudinal and shear waves along \({\langle }100{\rangle }\), \({\langle }110{\rangle }\) and \({\langle }111{\rangle }\) directions. The second- and third-order elastic constants of CeX have also been computed in the temperature range 0 K to 500 K using Coulomb and Born–Mayer potential upto second nearest neighbours. The computed values of these elastic constants have been applied to find out Young’s moduli, bulk moduli, Breazeale’s non-linearity parameters, Zener anisotropy, ultrasonic velocity, ultrasonic Grüneisen parameter, thermal relaxation time, acoustic coupling constants and ultrasonic attenuation. The fracture/toughness ratio is less than 1.75, which shows that the chosen materials are brittle in nature as found for other monopnictides. The drag coefficient acting on the motion of screw and edge dislocations due to shear and compressional phonon viscosities of the lattice have also been evaluated for both the longitudinal and shear waves. The thermoelastic loss and dislocation damping loss are negligible in comparison to loss due to Akhieser damping (phonon–phonon interaction). The obtained results for CeX are in qualitative agreement with other semi-metallic monopnictides.