2-Amino­terephthalic acid–4,4′-bipyridine (1/1)

The asymmetric unit of the title compound, C10H8N2·C8H7NO4, contains two half-mol­ecules, which constitute a 1:1 co-crystal. The 2-amino­terephthalic acid mol­ecule is situated on an inversion center being disordered between two orientations in a 1:1 ratio. In the 4,4′-bipyridine mol­ecule, which is situated on a twofold rotational axis, the two pyridine rings form a dihedral angle of 37.5 (1)°. In the crystal, mol­ecules are held together via inter­molecular N—H⋯O and O—H⋯N hydrogen bonds. The crystal packing exhibits π–π inter­actions between the aromatic rings with a centroid–centroid distance of 3.722 (3) Å

Electrospun PHB/Chitosan Composite Fibrous Membrane and Its Degradation Behaviours in Different pH Conditions

Peripheral nerve injury (PNI) is a neurological disorder that causes more than 9 million patients to suffer from dysfunction of moving and sensing. Using biodegradable polymers to fabricate an artificial nerve conduit that replicates the environment of the extracellular matrix and guides neuron regeneration through the damaged sites has been researched for decades and has led to promising but primarily pre-clinical outcomes. However, few peripheral nerve conduits (PNCs) have been constructed from controllable biodegradable polymeric materials that can maintain their structural integrity or completely degrade during and after nerve regeneration respectively. In this work, a novel PNC candidate material was developed via the electrospinning of polyhydroxy butyrate/chitosan (PHB/CS) composite polymers. An SEM characterisation revealed the resultant PHB/CS nanofibres with 0, 1 and 2 wt/v% CS had less and smaller beads than the nanofibres at 3 wt/v% CS. The water contact angle (WCA) measurement demonstrated that the wettability of PHB/CS electrospun fibres was significantly improved by additional CS. Furthermore, both the thermogravimetric analysis (TGA) and differentiation scanning calorimetry (DSC) results showed that PHB/CS polymers can be blended in a single phase with a trifluoracetic solvent in all compositions. Besides, the reduction in the degradation temperature (from 286.9 to 229.9 °C) and crystallinity (from 81.0% to 52.1%) with increasing contents of CS were further proven. Moreover, we found that the degradability of the PHB/CS nanofibres subjected to different pH values rated in the order of acidic > alkaline > phosphate buffer solution (PBS). Based on these findings, it can be concluded that PHB/CS electrospun fibres with variable blending ratios may be used for designing PNCs with controlled biodegradability

Tetra­kis[(4-meth­oxy­carbon­yl)anilinium] hexa­chloridostannate(IV) dichloride

The asymmetric unit of the title compound, (C8H10NO2)4[SnCl6]Cl2, contains two (4-meth­oxy­carbon­yl)anilinium cations, one chloride anion and one half of a hexa­chlorido­stannate(IV) dianion situated on a twofold rotation axis. All aminium H atoms are involved in N—H⋯Cl hydrogen bonding, which consolidate the crystal packing along with weak C—H⋯O inter­actions

Advances on layered transition-metal oxides for sodium-ion batteries: a mini review

The energy storage mechanism and manufacturing equipment of sodium-ion batteries (SIBs) and lithium-ion batteries (LIBs) are similar. However, SIBs offer several advantages, such as low cost, abundant resources, environmental friendliness, and high safety. Consequently, they have garnered significant attention. SIBs are poised to be potential replacements for LIBs and represent ideal candidates in the field of large-scale energy storage. Layered transition-metal oxides (TMOs) are considered highly promising cathode materials due to their high average voltage, high specific capacity, and ease of synthesis. This paper provides a review of recent advances in layered TMOs for SIBs, including NaxCoO2, NaxMnO2, NaxFeO2, and their derivatives. Furthermore, the challenges and prospects in the development of layered TMOs are also discussed. It is hoped that this review will assist in the design and preparation of SIBs with superior electrochemical performance and further facilitate their practical application

Bacillus subtilis Inhibits Vibrio natriegens-Induced Corrosion via Biomineralization in Seawater

The marine bacterium, Vibrio natriegens, grows quickly in a marine environment and can significantly accelerate the corrosion of steel materials. Here, we present an approach to inhibit V. natriegens-induced corrosion by biomineralization. The corrosion of steel is mitigated in seawater via the formation of a biomineralized film induced by Bacillus subtilis. The film is composed of extracellular polymeric substances (EPS) and calcite, exhibiting stable anti-corrosion activity. The microbial diversity and medium chemistry tests demonstrated that the inhibition of V. natriegens growth by B. subtilis was essential for the formation of the biomineralized film

Corrosion Behavior of 2205 Steel in Simulated Hydrothermal Area

Deep-sea hydrothermal area has a lot of mineral resources, and study the corrosion behavior of metal in deep-sea hydrothermal area is useful for marine resource development. Electrochemical impedance spectroscopy, linear polarization, potentiodynamic polarization and Mott-Schottky analysis were used to study the electrochemical properties of 2205 steel in 20 MPa hydrostatic pressure 3.5% NaCl solution with different temperatures. Corrosion morphologies and corrosion products of 2205 steel after electrochemical tests were analyzed by SEM, EDS and white light interferometry. The results show that 2205 steel has good pitting resistance under 25 degrees C in simulated hydrothermal area, pit occurred on the surface of 2205 steel after the solution temperature reaching 65 degrees C crack-shaped pit occurred on the surface of 2205 steel under 150 and 200 degrees C Pit occurs in austenite phase at 65 degrees C and occurs in ferrite phase at 100 similar to 200 degrees C Impedance and linear polarization resistance of 2205 steel first decrease and then increase with temperature increasing in simulated hydrothermal area, and impedance and linear polarization resistance under 150 degrees C are lowest. Pitting potential of 2205 steel first negative shift and then positive shift, and carrier density of passive film formed in simulated hydrothermal area increase with temperature increasing

Artificially stacked atomic layers: Toward new van der Waals solids

El pdf del artículo es la versión de autor.-- et al.Strong in-plane bonding and weak van der Waals interplanar interactions characterize a large number of layered materials, as epitomized by graphite. The advent of graphene (G), individual layers from graphite, and atomic layers isolated from a few other van der Waals bonded layered compounds has enabled the ability to pick, place, and stack atomic layers of arbitrary compositions and build unique layered materials, which would be otherwise impossible to synthesize via other known techniques. Here we demonstrate this concept for solids consisting of randomly stacked layers of graphene and hexagonal boron nitride (h-BN). Dispersions of exfoliated h-BN layers and graphene have been prepared by liquid phase exfoliation methods and mixed, in various concentrations, to create artificially stacked h-BN/G solids. These van der Waals stacked hybrid solid materials show interesting electrical, mechanical, and optical properties distinctly different from their starting parent layers. From extensive first principle calculations we identify (i) a novel approach to control the dipole at the h-BN/G interface by properly sandwiching or sliding layers of h-BN and graphene, and (ii) a way to inject carriers in graphene upon UV excitations of the Frenkell-like excitons of the h-BN layer(s). Our combined approach could be used to create artificial materials, made predominantly from inter planar van der Waals stacking of robust bond saturated atomic layers of different solids with vastly different properties.A.R. acknowledges financial support from the European Research Council Advanced Grant DYNamo (ERC-2010-AdG -Proposal No. 267374), Spanish MICINN (FIS2010-21282-C02-01), ACI Promociona (ACI2009-1036), Grupos Consolidados UPV/EHU del Gobierno Vasco″ (IT-319-07), the EU project THEMA (Contract Number 228539), and the Ikerbasque Foundation. Y.Y. acknowledges funding from the National Natural Science Foundation of China (51042013, 51003056), the Shanghai City Committee of Science and Technology Project (10170502400), and the National Oceanic Administration Project (201005028-4). J.T.-T. acknowledges the support from PGE and CONACYT (213780).Peer Reviewe

Sliding wear behavior of plasma sprayed Fe3Al–Al2O3 graded coatings

Fe3Al&ndash;Al2O3 double-layer coatings (DC), Fe3Al-Fe3Al/50%Al2O3&ndash;Al2O3 triple-layer coatings (TC) and Fe3Al-Al2O3 graded coatings (GC) were produced from a series of Fe3Al/Al2O3 composite powders with different compositions on low carbon steel substrate using PLAXAIR plasma spraying equipment. Friction behaviors and wear resistance of the three kinds of coatings have been investigated under different loads. Tests were carried out using an MRH-3 standard machine, in lineal contact sliding under dry condition against hardmetal, at a sliding velocity of about 1.57 ms&minus;1. Wear rates under different loads were measured and the friction coefficients were recorded. SEM analysis was carried out to identify the wear mechanisms. The results show that the GC has higher wear-resistance than DC and TC. The tribological characteristics of graded coating were different along the depth of the coatings, and the surface of coatings with pure Al2O3 does not show the best wear resistance. The wear rate and friction coefficients were also different under different loads. The failure types of plasma-sprayed Fe3Al-Al2O3 graded coatings in lineal contact were: loosening of ceramic particles, crack nucleation and propagation, brittle fracture, plastic deformation, and adhesive wear.<br /

Wear and Corrosion Properties of Plasma Transferred Arc Ni-based Coatings Reinforced with NbC Particles

The wear and corrosion resistance of Ni-based niobium carbide (NbC) coatings were investigated via scanning electron microscopy, energy dispersive spectrometry, particle size analysis, X-ray diffraction, electrochemical polarization, electrochemicl impedance spectroscopy, digital microhardness testing and wear testing. The results showed that the substrate was mainly composed of a γ-Cr (Fe) solid solution, and the composite coating was composed of FeNi, NbC, and Ni. In addition, the hardness of the coating increased gradually with increasing NbC content. The optimal corrosion resistance and wear resistance of the coating were realized at an NbC content of 20%