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Transmission electron microscopy (TEM) has evolved into a powerful characterization tool that allows visualization of materials with finer resolution than any other type of microscope in existence. While numerous areas of the physical and biologically sciences and engineering benefit tremendously from TEM and its analytical features, the highest resolution can only be achieved if a sample fulfills certain requirements, including an optimal thickness as well as a sufficiently long e‐beam stability. At a fundamental level, the physical and chemical properties of organic polymers are generally problematic in conjunction with TEM, as they experience damage from the electron beam more readily than their hard materials counterparts. However, progress in polymer characterization using TEM has evolved considerably and the polymer community stands to benefit greatly from continued growth going forward. [ABSTRACT FROM AUTHOR]

Different long-chain primary alkylamines such as octylamine, dodecylamine, tetradecylamine, hexadecylamine or octadecylamine were used to stabilize Ni-NiO nanoparticles (metal:stabilizer ratio of 1:10) by an organometallic method in organic medium to evaluate their effect on the microstructural and magnetic properties. The Ni-NiO stabilized nanoparticles were characterized by Fourier transformed infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), conventional transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and dynamic light scattering (DLS). The results indicated an adequate stabilization of Ni nanoparticles with the different primary alkylamines. The semi-quantitative analysis suggests that Ni surface composition is a combination of the metallic state with NiO, NiOOH and NiO, but the chain length modified the content and proportion of these compounds. The highest Ni metallic state (57.2 at. %) was obtained with tetradecylamine as stabilizer. The morphology of the samples is similar to a core–shell semi-spherical, but the particle size tends to reduce with the alkyl chain length of primary amines from 20 to 8 nm. The saturation magnetization (Ms) showed important variations depending on the surface composition, for which variable particle size and Ni metallic content were determining factors for the magnetic response. [ABSTRACT FROM AUTHOR]

Ni nanoparticles (NiNPs) were prepared by thermal decomposition of nickel acetylacetonate in the presence of a third generation polypyridylphenylene dendrimer (G3) which acts both as a coordinating ligand due to presence of pyridine groups and as a stabilizing agent due to highly branched architecture. Transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), and X‐ray photoelectron spectroscopy (XPS) were used to extensively evaluate structure and morphology of the synthesized NiNPs@G3. The selected area electron diffraction (SAED) allowed us to conclude about fcc structure of NiNPs while STEM EDS analysis demonstrated a formation of core‐shell NiO@Ni NPs. Further, the catalyst was tested in selected Suzuki‐Miyaura cross‐coupling reactions at mild conditions and demonstrated a high efficiency at low Ni loading with negligible content of Ni0 on the NP surface. The functional hyperbranched dendrimer macromolecule provided an excellent stabilization for NiNPs@G3 while allowing an easy access for reactants to catalytic sites. The high activity of the catalyst in the recycling experiments was maintained by the absence of Ni leaching from the NiNPs@G3. [ABSTRACT FROM AUTHOR]

Reinforcement of aluminum and aluminum alloys with graphene has been intensively practiced by researchers in the past dozen years. The role of Al4C3, which could be produced unintentionally or purposefully during the composite production, was controversial until it was found that nano-sized carbides were beneficial for strengthening the composites. aluminum-graphene-nano-sized Al4C3 composites were produced by us using the powder metallurgical method and subsequent annealing. The microstructure was investigated using light microscopy (LM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), transmission electron microscopy (TEM), and high resolution transmission electron microscopy HRTEM. Nano-sized carbides were found at the interface aluminum-graphene. The formation of a chemical bond between aluminum and graphene during annealing was proved. Lower values of the microhardness and strength characteristics of the composites after extrusion and subsequent annealing during which nano-sized carbides are formed were found in comparison with those obtained after extrusion. It could be supposed that the annealing processes contribute more to the reduction in microhardness and strength characteristics than nano-sized carbides contribute to its increase. The presence of a strong chemical bond between the graphene and the aluminum is manifested in the failure pattern, which is characterized by graphene nano-platelets and nano-sized carbides fracture and semi-pulled out or semi-slipped Al4C3 from the matrix. [ABSTRACT FROM AUTHOR]

This paper demonstrates a low-temperature solvothermal method of nitrogen-rich covalent organic framework (COF) onions. The atomic structure and the bonding features are revealed by high resolution transmission electron microscopy (TEM) and electron energy-loss spectroscopy (EELS). The novel COF onion provides potential applications in photocatalysts considering its suitable bandgap value of 2.56 eV. [Display omitted] Achieving hierarchical nanomaterials from a bottom-up approach remains challenging. Here, we report a closed-cage, onion nanostructure of covalent organic framework (COF) obtained through a low-temperature solvothermal synthesis. Atomic resolution transmission electron microscopy revealed the atomic arrangement in this COF onion, in which rich nitrogen was uniformly embedded in the periodic porous graphitic framework. The COF onion structure displayed graphitic features at a 0.33 nm interlayer spacing with Van der Waals interactions predominated between the layers. The onion layers exhibited significant heterogeneity in layer stacking by adopting a combination of different stacking modes. Defects were also found, such as five- or seven-member rings deviating from the perfect hexagonal lattice. These geometrical defects resulted in curving the 2D layers, which may have promoted the formation of onion nanostructures through a layer-by-layer attachment. We constructed a corresponding model that predicts COF onion properties. This novel onion exhibited a bandgap value of 2.56 eV, resembling other carbon-based nanomaterials, suggesting potential applications in sensors, photocatalysts, and nanoelectronics. [ABSTRACT FROM AUTHOR]

Glassy carbon is frequently used in electrochemical research due to its presumed robust electrochemical performance. Although it is widely utilized as a rotating disc electrode material, the modification of glassy carbon during electro‐catalytic process is rarely emphasized or characterized. In this report, we investigated the structural modification of glassy carbon imparted by electrochemical oxidation in acidic media and compared the behavior with graphite. The functional groups generated from electrochemical oxidation in both electrodes possess similar electrochemical properties. However, above an oxidation potential of 1.8 V (vs. reversibly hydrogen electrode), glassy carbon exhibits a lower electrochemical capacitance compared to graphite. We propose that the existence of electrochemically inactive species, originating from the non‐graphitic portion of glassy carbon is attributed to such deterioration. Additionally, high resolution scanning electron microscopy (HR‐SEM) and high‐resolution transmission electron microscopy (HR‐TEM) images corroborate how electrochemical oxidation prevails for glassy carbon electrodes at oxidative potentials. The overall analysis leads us to propose a corrosion mechanism for glassy carbon in acidic solution. [ABSTRACT FROM AUTHOR]

The morphology and crystallography of E -(Al 18 Cr 2 Mg 3) nano dispersoids in 7475 Al alloy have been studied by using transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) and electron tomography (ET). Seven distinct morphologies have been three-dimensionally distinguished at the nanoscale: (i) triangular plates on {111} Al , (ii) hexagonal plates on {111} Al , (iii) rods parallel to <110> Al , (iv) small tetrahedra with {111} Al facets, (v) small octahedra, (vi) spheres and (vii) irregular shapes. Twinning can contribute to the diverse morphologies of E nano dispersoids. The orientation relationships (ORs) between E nano dispersoids and Al matrix have been systematically investigated by selected area electron diffraction (SAED) patterns, HRTEM and matrix calculation. The results from the matrix calculation indicate the absence of clear ORs between E nano dispersoids and Al matrix in 7475 Al alloy. • The morphology of E -(Al 18 Cr 2 Mg 3) nano dispersoids in 7475 Al alloy have been studied by using electron tomography. • Seven distinct morphologies have been three-dimensionally distinguished at the nanoscale. • Twinning can contribute to the diverse morphologies of E nano dispersoids. • Based on matrix calculation, there are no clear orientation relationships between E dispersoids and Al matrix. [ABSTRACT FROM AUTHOR]

Mechanical stirring of bulk Te in N‐methyl‐2‐pyrrolidone (NMP) solution at room temperature resulted in the formation of free‐standing few‐layer (∼1.2–2.8 nm) crystalline ultrathin nanosheets of tellurene with a large lateral thickness (∼1–1.6 μm) as confirmed by atomic force microscopy (AFM). High‐resolution transmission electron microscopy (HRTEM) confirms the presence of α‐ and β‐phases of tellurene. First‐principle density functional theoretical (DFT) based electronic structure calculations demonstrate the indirect band gap of bi‐layer β‐tellurene. The band gap decreases with increasing number of layers in the tellurene nanosheet. [ABSTRACT FROM AUTHOR]

Magnetoplumbite barium hexaferrite (BaFe 11.8 Co 0.2 O 19) is synthesised through sol-gel auto-combustion method under two pH conditions of precursor solutions (acidic i.e. pH < 1 and neutral i.e. pH = 7). The XRD analysis followed by Reitveld refinement indicates the formation of phase pure samples in both cases but the barium hexaferrite obtained from acidic precursor solution has smaller crystallite sizes. The Transmission Electron Microscopy (TEM) analysis followed by High Resolution Transmission Electron Microscopy (HRTEM) confirms a lower particle size of ∼20 nm for barium hexaferrite synthesised from acidic pH precursor solution. The shift in Raman peak (520-540 cm−1) by 20 cm−1, represents the whole structural block and further confirms the differences in the distribution of particle sizes due to the method of synthesis. The magnetic studies display a lower coercive field for the samples with smaller particle sizes. This is due to the crystalline size-induced microstrain that controls the magneto-crystalline anisotropy, shape anisotropy and stress anisotropy. The electromagnetic characterisation confirms broader absorption in the range of 8–18 GHz (X -band) with R L ≤ −7 db for the entire range for the samples with smaller particle sizes. [ABSTRACT FROM AUTHOR]

• Hard/soft nanocomposites were prepared by one-pot sol–gel auto-combustion technique. • The composition exhibited a good exchange-coupling. • Strong correlation between the chemical composition and electrodynamic parameters. This work presented the effect of Ho substitution on magnetic and electrodynamic properties of hard-soft SrBaHo x Fe 12-x O 19 @NiFe 2 O 4 (x ≤ 0.06) nanocomposites (H/S Ho → SBFeO@NFO NCs) which were produced through one-pot citrate sol–gel method. The structure and morphology were explored using X-ray diffractometry (XRD) and scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HR-TEM). By scrutinizing hysteresis curves at temperatures of 300 K (Room temperature, RT) and 10 K, the magnetic characteristics of H/S Ho → SBFeO@NFO (x ≤ 0.06) NCs have been investigated. These materials display smooth, open hysteresis loops at both temperatures, indicating their ferrimagnetic nature and highlighting the presence of exchange-coupling interactions within the nanocomposites. The SQR (squareness ratio) values, below 0.5 at both high and low temperatures, indicate a multi-domain structure in the H/S Ho → SBFeO@NFO (x ≤ 0.06) NCs. Magnetic parameters demonstrate fluctuations with growing Ho content. The introduction of Ho3+ ions notably reduce the coercivity of the undoped H/S Ho → SBFeO@NFO (x ≤ 0.06) NCs. Saturation magnetization (M s) and magnetic moment show similarity between undoped and Ho-doped nanocomposites at all concentrations, except for x = 0.06, where a considerable decrease occurred at both temperatures. Our findings propose that by controlling the concentration of Ho3+ ions, the magnetic properties of H/S Ho → SBFeO@NFO NCs can be precisely adjusted. Electromagnetic properties of the H/S Ho → SBFeO@NFO NCs were investigated in the range 33–50 GHz. Frequency dispersions of the real/imaginary parts of permittivity and permeability were determined from S11 to S21 parameters. RL coefficient demonstrated intensive electromagnetic absorption with average level −16...−23 dB in this frequency range that corresponded to the absorption of the natural media. [ABSTRACT FROM AUTHOR]

This study aims to clarify the growth process of the β-phase in Al-Mg-Si alloys from the point of view of morphological evolution. The orientation relationship, shape, growth process, misfit value, and interfacial condition between the β-phase and Al matrix were investigated using high-resolution transmission electron microscopy (HR-TEM), focused ion beam (FIB), and optical microscope (OM). In a previous study, the growth process and shape of the β-phase were determined using scanning electron microscopy (SEM). It was proposed that the truncated octahedron (8{111}, 6{100} facets) transforms into a hexahedron (6{100} facets). This study proposes that two new three-dimensional shapes of the β-phase exist between the truncated octahedron and hexahedron, and we identified the {111} β facets at the edges of the β-phase. We proposed the morphology evolution during the growth process of Mg 2 Si crystals and calculated the misfit to understand that the unstable {111} β facet has a higher misfit value compared to the {001} β and {011} β facets. Our observations provide insight into how they influence the behavior of Mg 2 Si crystals, which is crucial for predicting the microstructural evolution of Al-Mg-Si alloys and for designing materials with desired properties. • Investigated the morphology evolution of the β-phase in Al-Mg-Si alloys. • Explored β-phase orientation relationship, shape, and growth process using HR-TEM, FIB, and OM. • Discovered {111} β facets and proposed new three-dimensional shapes for the β-phase. • Calculated misfit values, revealing the instability of the (111) β facet compared to (001) β and (011) β facets. • Contributed to understanding microstructural evolution in Al-Mg-Si alloys and material design. [ABSTRACT FROM AUTHOR]

Pre-stretched strains, 2%, 4%, and 6%, were conducted on the friction-stir-welded dissimilar 2024-to-7075 aluminum alloy joints for strengthening purpose. Tensile tests and microhardness measurements were performed to evaluate the strengthening effect. Transmission electron microscopy and high resolution transmission electron microscopy examinations were employed to characterize precipitates and dislocation structures of the as-welded and pre-stretched joints to elucidate the intrinsic strengthening mechanisms. Results showed that the yield and tensile strengths of the pre-stretched 6% joint respectively increased 147.9 MPa and 31.1 MPa when compared with the as-welded joint. The strain hardening rates of 2024 lower hardness zone (LHZ)-II and 7075 LHZ were higher at the pre-stretched strain rate of 1 mm/min than those of 2 mm/min based on the microhardness area evolution. The yield sequence of the as-welded joint was 2024 LHZ-II, 2024 LHZ-I, 7075 LHZ, stir zone (SZ), and 2024 base material. The appearance of dislocation tangles, dislocation walls, dislocation cells, dislocation pile-ups in the 2024 LHZ-II and 7075 SZ combined with the severe interactions between dislocation structures and precipitates were the dominant strengthening factors. It was very interesting that dislocations provided a diffusion path for Mg atoms and Cu atoms in 2024 LHZ-II during the pre-stretching process. • Pre-stretching was used to strengthen the FSWed dissimilar aluminum alloys joints. • Yield sequence of the FSWed dissimilar aluminum alloys joints was identified. • The strengthened lower hardness zone contributed to the reinforced global joint. • Several kinds of dislocations structures induced by the pre-stretching process. • Dislocations provided a diffusion path for Mg and Cu atoms in 2024 aluminum alloy. [ABSTRACT FROM AUTHOR]

Boron doped diamonds (BDD) with boron concentration above 1019 at./cm3, grown under conditions of high isostatic pressure by the temperature gradient method, were studied by Transmission Electron Microscopy methods, EELS analysis and X-ray diffraction analysis. It was shown that boron is distributed unevenly in the grown crystal. It was found that in places of maximum boron content, interplanar distances d 111 increase from 0.206 to approximately 0.2065 nm. Parallel bands were discovered, the boundaries of which are fragments of the intermediate carbon phase (ICP-phase). Numerous twins along the {111} plane, as well as fragments of rhombohedral 9R phase, were discovered. [Display omitted] [ABSTRACT FROM AUTHOR]

Herein we report a facile approach for the preparation of a magnetically separable Fe3O4@poly(m‐phenylenediamine)@Cu2O nanocatalyst and its catalytic efficiency in the synthesis of 5‐phenyl‐[1,2,3]triazolo[1,5‐c]quinazolines from (E)‐1‐bromo‐2‐(2‐nitrovinyl)benzenes, aldehydes, and sodium azide under mild reaction condition is described. The morphology, chemical composition, interior structure and magnetic properties of the Fe3O4@PmPDs@Cu2O nanocomposites were studied using powder X‐ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, energy dispersive X‐ray spectroscopy, X‐ray photoelectron microscopy, vibrating sample magnetometer and nitrogen adsorption‐desorption technique. The as‐prepared Fe3O4@PmPDs@Cu2O nanocatalyst was simply recovered using external magnet and reused up to successive six runs with no obvious loss in its catalytic efficiency and structural integrity (confirmed by powder X‐ray diffraction and transmission electron microscopy of recycled nanocatalyst) along with low leaching of copper (2.32 ppm) and iron (0.008 ppm) ions. The present protocol has a broad substrate scope with high yield in shorter reaction time and it does not require any additive or base. Overall, it has better green chemistry metrices like low E‐factor (0.93), process mass intensity (1.93), high reaction mass efficiency (51.9 %) and carbon efficiency (95 %). [ABSTRACT FROM AUTHOR]

Green synthesis of metal oxide nanoparticles (NPs) is a viable alternative methodology because of cost-effective and availability of environmentally friendly templates for desired application, which has attracted the attention of researchers in recent years. In the present study, Co3O4 NPs were synthesized in various volume ratios in the presence of Solanum tuberosum leaf extract as a template. The synthesized Co3O4 NPs were characterized by X-ray diffraction (XRD), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), surface area electron diffraction (SAED), UV-Vis diffuse reflectance spectroscopy (UV-DRS), and Fourier transform infrared (FTIR) spectroscopy. XRD analysis found that the average crystalline sizes for the 1 : 2, 1 : 1, and 2 : 1 volume ratios was 25.83, 21.05, and 27.98 nm, respectively. SEM-EDX and TEM analyses suggest that the green-synthesized Co3O4 NPs are spherical in shape without the presence of impurities. The band gap E g values of the 1 : 2, 1 : 1, and 2 : 1 volume ratios of Co3O4 NPs were found to be 1.83, 1.77, and 2.19 eV, respectively. FTIR analysis confirmed the presence of various bioactive ingredients within the leaf extract of Solanum tuberosum. Co3O4 NPs-modified electrodes showed better sensing capability towards ascorbic acid and citric acid due to enhanced electron transfer kinetics. Among three volume ratios (1 : 2, 1 : 1, and 2 : 1) of Co3O4 nanoelectrodes, 1 : 1 and 2 : 1 were identified as the best performing nanoelectrodes. This is possibly due to the high catalytic behavior and the more homogenized surface structure. Co3O4 (1 : 2) nanodrug showed the enhanced antibacterial activity (16 mm) towards S. aureus which is attributed to the formation of enhanced reactive oxygen species (ROS). [ABSTRACT FROM AUTHOR]

A standalone 100 kV field emission gun (FEG) has been developed that can be installed and operated on a standard transmission electron microscopy electron optical column or custom designed high voltage electron optical columns. The FEG comprises a thermally assisted field emission cathode and an asymmetric electrostatic lens that can operate from 20 to 100 kV in an ultrahigh vacuum (UHV) chamber. In its current configuration, the FEG has spherical and chromatic aberration coefficients (Cs and Cc, respectively) in the range of Cs = 607–670 mm and Cc = 60–87 mm at 100 keV over a range of working distances of 50–206 mm from the exit plane of the FEG unit. A dedicated high voltage supply unit with voltage ripples of less than 1 ppm at 100 kV has also been developed. The FEG is transported under UHV and does not require the use of SF6 gas during operation, as is customary in high voltage FEG TEMs. Preliminary results of operating the FEG on a Philips Tecnai 12 and a JEOL JEM-1400HR TEM show the resolution of gold (111) crystal planes at 0.235 nm and (200) planes at 0.202 nm. [ABSTRACT FROM AUTHOR]

To develop wide bandgap materials for solar cells and other optoelectronic devices, undoped hydrogenated silicon oxide (SiOx:H) thin films are prepared by conventional radio frequency plasma enhanced chemical vapor deposition (RF PECVD) method. The variation of carbon dioxide dilution ( Y c ) on optoelectronic and structural properties are studied thoroughly by keeping silane and hydrogen gas flow fixed. Surface morphology of the SiOx:H films have been studied by Field Emission Scanning Electron Microscopy (FESEM) and Atomic Force Microscopy (AFM). Distinct silicon nanocrystallites of average diameter ∼ 3–6 nm embedded uniformly in amorphous SiOx network have been observed in high resolution Transmission Electron Microscopy (HRTEM). From Fourier Transform Infrared spectra (FTIR), it is observed that oxygen content ( C o ) increases initially with Y c and afterwards it decreases. Strong room temperature photoluminescence (PL) peak is obtained for the as-deposited films having lower oxygen content ( C o ). The origin of room temperature PL spectra and its correlation with C o can be explained by quantum confinement effect (QCE) theory. In the current study, undoped hydrogenated silicon oxide (SiOx:H) films were prepared by varying carbon dioxide dilutions with fixed silane and hydrogen gas flow, and a strong room temperature photoluminescence peak is observed for lower value of oxygen content. The microstructural properties of the films have also been studied by AFM, FESEM and HRTEM. In TEM study, a uniform distribution of silicon nanoparticles of average diameter ∼3–6 nm is clearly observed over the amorphous SiOx:H network. [ABSTRACT FROM AUTHOR]

Pyrolytic carbon (PyC) plays a critical role in many applications for its unique properties. In ceramic composite systems, the elastic properties of PyC at the fiber/matrix interface drive toughening mechanisms, enabling structural performance at increased operating temperatures. PyC expresses a wide range of crystallographic texture depending on fabrication parameters. As a result, modelling and optimization requires direct understanding of the texture-property relationships at the relevant length scales. This research leverages high-resolution transmission electron microscopy (HRTEM) to link the PyC microstructure to the elastic response observed via digital image correlation (DIC) during micropillar compression. The HRTEM and DIC results quantitatively resolve a gradient for microstructural texture and Young's modulus respectively, showing that disordered texture increases compressive stiffness normal to the average orientation of the PyC basal planes. The values for modulus ranged from 55 to 150 GPa, which are large compared to most experimental methods, but may be more realistic considering the uniaxial stress state and length scale. The behavior supports findings from numerical homogenization models, suggesting that this advanced technique may provide a path forward for optimization and validation of these nanoscale elasticity models. [Display omitted] [ABSTRACT FROM AUTHOR]

Cuboid‐shaped anatase TiO2 nanocrystals with co‐exposed {101} and [111]‐facets (or {101} and {100} facets), diamond‐shaped, rod‐like and irregular anatase TiO2 nanocrystals with dominant {010} facets were controllably synthesized from titanium (IV) ethoxide (TEOT) using HF as a capping agent via a facile sol‐gel procedure, and characterized by X‐ray powderdiffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), nitrogen adsorption, photoluminescence (PL) spectra, UV‐vis diffuse reflectance spectra,and electrochemical impedance spectroscopy (EIS). For the as‐prepared anatase TiO2 nanocrystals, the 0.5HF‐TiO2 revealed the best photocatalytic efficiency under UV light irradiation: 94.1 % of methylene blue (MB) was photodegraded within 90 min. The reaction rate constant k(min−1) was 1.39, 1.47, 1.59, 1.66, 1.92, 2.75, and 30.5 times higher than that of 2.0HF‐TiO2 (2.20×10−2 min−1), 1.5HF‐TiO2 (2.07×10−2 min−1), 1.0HF‐TiO2 (1.92×10−2 min−1), 2.5HF‐TiO2 (1.84×10−2 min−1), 3.0HF‐TiO2 (1.59×10−2 min−1), Bodi‐TiO2 (1.11×10−2 min−1), and the blank sample (0.10×10−2 min−1), respectively. Compared to other as‐prepared anatase TiO2 nanocrystals with the similar co‐exposed crystal facets, the highest efficiency of 0.5HF‐TiO2 could be attributed to the minimum crystal size,narrower pore size distribution, the maximum specific surface area, the lowest PL intensity and charge‐transfer resistance, andthe smallestrecombination resistance. [ABSTRACT FROM AUTHOR]

In a sample with nominal composition BiCr2S5 a new misfit layer compound has been synthesized and studied via transmission electron microscopy (TEM). It presents a composite modulated structure with a composition that can be formulated as (BiS)1.19[(CrS2)‐Bi1/3‐(CrS2)]. It consists of the periodic stacking of a Q layer (BiS) with two H layers (CrS2), ...QHHQHH..., with additional bismuth atoms inserted between the H layers. Selected area electron diffraction (SAED) patterns show an almost commensurate fit between the pseudo‐tetragonal Q (BiS) and the pseudo‐orthohexagonal H (Bi1/3Cr2S4) subcells along the misfit direction a, being b the same for both sublattices and c the layers stacking direction. In addition to the characteristic misfit modulation between the two sub‐structures, a second modulation is observed in the H sub‐structure produced by the ordering of bismuth atoms within the Van der Waals gap that occurs between consecutive H layers. High resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy (STEM) images show ordered stacking sequences between the (BiS) and (Bi1/3Cr2S4) layers. Besides, disordered intergrowths have been occasionally found as well as different kinds of twinning defects. [ABSTRACT FROM AUTHOR]

The complex nature of nodular graphite nuclei was studied in a partially solidified and quenched spheroidal graphite iron (SGI) that contained small graphite nodules. The reduced graphite to nuclei diameter ratio obtained by the accelerated solidification process increased the probability of nuclei exposure during metallographic cross sectioning. Ten thousand graphite nodules were analyzed to identify nucleation sites using an automated scanning electron microscopy-energy dispersive X-ray (SEM-EDX) system and the resultant ternary plot presents a chemistry of oxides, sulfides and nitrides located inside the graphite nodules. Focused ion beam milling was used to extract thin foil specimens and extensive high-resolution transmission electron microscopy (TEM) analysis of several representative nuclei was conducted. The nucleus of a graphite nodule was composed of a Mg – O core with Mg–Ca–S and Mg–Al–Si – N compounds attached on its sides. The crystallographic orientation relationships between different nucleating compounds and between graphite and nucleating compounds were analyzed using selected area diffraction patterns. For the first time, the direct observation of the nuclei interfaces revealed the presence of nano-structured boundary layers. The formation of a complex nodular graphite nucleus was thermodynamically simulated and the nucleation behavior of the complex compound was linked to the novel experimental results. Image 1 [ABSTRACT FROM AUTHOR]

Optical reflectance and bright-field and high-resolution transmission electron microscopy studies of radiation damage induced by implantation of arsenic ions with 190 keV and 350 keV energy and 1014 cm–2 fluence in molecular-beam epitaxy-grown Hg0.7Cd0.3Te films were performed. A similarity in defect pattern formed by arsenic implantation in Hg1−xCdxTe with x ≈ 0.2 and x ≈ 0.3 straight after the implantation was observed with formation of three nano-size defect layers containing dislocation loops of vacancy- and interstitial-types, single dislocations and lattice deformations. After post-implantation arsenic activation annealing, most of these defects in our Hg0.7Cd0.3Te films, in contrast to Hg0.8Cd0.2Te films, disappeared. This effect is explained by the reduced influence of the electric field of the graded-gap surface layer on the diffusion of charged point defects under annealing. [ABSTRACT FROM AUTHOR]

Metal nanoparticles (NPs) in a transparent dielectric matrix represent a very intriguing system due to the plasmonic absorption tunable in the range of visible wavelengths. Herein, the preparation and physical characterization of plasmonic titania–silver dots thin films are reported. The synthesis parameter that leads to making a TiO2 matrix in which the Ag NPs are actually incorporated is carefully analyzed and controlled. Morphological (scanning electron microscopy, transmission electron microscopy, high resolution electron microscopy), structural (selected area diffraction, X‐ray diffraction), and spectroscopic (Raman spectroscopy) characterization techniques attest that the Ag NPs are spherical and homogeneously distributed into the TiO2 dielectric matrix in the structural modification of anatase. The study of the optical properties of films concludes the work. Plasmonic resonance is analyzed according to the light scattering theory. [ABSTRACT FROM AUTHOR]

Ultra-high density of parallel planar defects is discovered within WC grains in V-doped cemented carbide. High resolution transmission electron microscopy (HRTEM) shows that such defects are stacking faults on the {10 1 ‾ 0} prismatic planes. The presence of multiple stacking faults within WC grain gives rise to a series of anomalous diffraction patterns, including the streaking of diffraction spots and forbidden fractional diffraction spots. Interestingly, quantitative analysis indicates that the density of stacking faults within the V-doped sample is one order of magnitude higher than that of the Ti-doped counterpart. Because the two doped samples are processed under the same condition, we conclude that the planar defects of WC grains in V-doped samples are largely produced during the sintering of cemented carbide. Aberration-corrected TEM images suggest that the formation of stacking faults can be ascribed to the merging of independently developed WC micro-pillars. The formation of such pillars can be further explained by the segregation of V-rich precipitates at the corners between basal and prismatic planes. The current finding not only unravels a new formation mechanism of stacking faults within WC grains, but also provides a new route to design superhard cemented carbides with interlaced stacking faults by simply doping solute atoms and controlling the sintering process, other than the traditional deformation method. [ABSTRACT FROM AUTHOR]

Twinning is commonly activated in plastic deformation of low stacking-fault face-centered cubic (Fcc) metals but rarely found in body-centered cubic (Bcc) metals under room temperature and slow strain rates. Here, by conducting in situ transmission electron microscopy (TEM) at atomic scale, we discover that, in stark contrast to those in most Fcc metals, a majority of deformation twins in Bcc metals are unstable and undergo spontaneously detwinning upon unloading. Such unexpected instability of Bcc twins is found to be closely related to the prevalence of the inclined twin boundaries—a peculiar structure where twin boundaries are not parallel to the twinning plane, and the degree of instability is in direct proportion to the fraction of the inclined twin boundary. This work provides significant insights into the structure and stability of deformation twins in Bcc metals. Body-centred cubic metals rarely show twinning during deformation. Here, the authors use high resolution transmission electron microscopy to show tungsten, a body-centred cubic metal, spontaneously undergoes detwinning when unloaded. [ABSTRACT FROM AUTHOR]

Nanocatalysts and single-atom catalysts are both vital for heterogeneous catalysis. They are recognized as two different categories of catalysts. Nevertheless, recent theoretical works have indicated that Au nanoparticles/clusters release Au single atoms in CO oxidation, and they co-catalyze the oxidation. However, to date, neither experimental evidence for the co-catalysis nor direct observations on any heterogeneous catalysis process of single-atom catalysts are reported. Here, the dynamic process of nanoporous Au to catalyze methane pyrolysis is monitored by in situ transmission electron microscopy with high spatial–temporal resolutions. It demonstrates that nanoporous Au surfaces partially disintegrate, releasing Au single atoms. As demonstrated by DFT calculation, the single atoms could co-catalyze the reaction with nanoporous Au. Moreover, the single atoms dynamically aggregate into nanoparticles, which re-disintegrate back to single atoms. This work manifests that under certain conditions, the heterogeneous catalysis processes of nanocatalysts and single-atom catalysts are not independent, where their dynamic co-catalysis exists. Nanocatalysts and single‐atom catalysts are generally considered as two categories with distinct performances. Here, in situ TEM study of catalytic methane pyrolysis over nanoporous Au reveals a highly dynamic process where co‐catalysis exists among various catalyst forms. [ABSTRACT FROM AUTHOR]

Summary: Geometrical phase analysis (GPA) is typically a powerful tool to investigate the deformation in high resolution transmission electron microscopy images and has been used in various fields. During GPA, strain components are calculated relative to an undistorted reference region. In the present work, the effect of reference region size on strain measurements has been investigated. Experimental measurements on a locally distorted gold nanoparticle exhibited that a small reference region below the GPA spatial resolution can introduce an inaccuracy in the measured displacement field, which appears as a significant increase in measured strains and severe fluctuation in phase images. The inaccuracy may be ascribed to an error of insufficient sampling. Our results suggest that a small reference region below the GPA spatial resolution should be avoided during GPA. This prerequisite should be paid more attention to during strain measurement on nanoparticles. [ABSTRACT FROM AUTHOR]

A nano-scaled shuffle-induced modulated structure and heating-induced ordering have been characterized in a metastable β-titanium alloy, Ti-5Al-5Mo-5V-3Cr, and their inter-relationship was investigated through in-situ and ex-situ conventional and aberration-corrected scanning/transmission electron microscopy and atom probe tomography. The nano-scaled O′ phase with a disordered orthorhombic-modulated structure formed by the { 011 } < 01 1 ¯ > β transverse phonon was characterized for the first time to be stable from room temperature to ∼200°C. The O″ phase with an ordered orthorhombic structure formed from the β phase during aging above the O′ phase solvus temperature, where Al segregation in nano-scaled regions led to ordering of every third {011} planes. Image, graphical abstract [ABSTRACT FROM AUTHOR]

(Ba0.5Sr0.5)(Co0.8Fe0.2)O3−δ (BSCF) with mixed ionic and electronic conductivity is promising as oxygen separation membrane. However, its exceptional oxygen permeability is linked to the cubic perovskite phase, which destabilizes below 825 °C. This work is concerned with the stabilizing effect of partial B-site substitution in BSCF by Ti (10%) and Nb (5% and 10%). In addition, the effect of B-site substoichiometry on the formation of CoO precipitates as nucleation sites for other secondary phases is studied. The focus of this work is laid on the analysis of the phase constitution in bulk material between 600 and 800 °C. Scanning electron microscopy and (scanning) transmission electron microscopy with high spatial resolution in combination with energy-dispersive X-ray spectroscopy are applied which allow to detect even small volume fractions of secondary phases. It is confirmed by quantitative analysis that Ti and Nb substitution reduces the formation of secondary phases up to ~ 95%. There is a solubility limit of Nb in BSCF, which leads to the precipitation of Nb-rich precipitates already at 5% Nb substitution in contrast to Ti which is fully soluble even at 10% substitution. Despite of that, BSCF doped with 5% Nb in combination with 5% substoichiometric B-site occupation is the most promising material, because it shows the lowest overall volume fraction of secondary phases (~ 0.8 vol% at 700 °C) and an almost negligible degradation rate in additionally recorded long-term resistivity measurements. [ABSTRACT FROM AUTHOR]

(Ba0.5Sr0.5)(Co0.8Fe0.2)O3−δ (BSCF) with mixed ionic and electronic conductivity is promising as oxygen separation membrane. However, its exceptional oxygen permeability is linked to the cubic perovskite phase, which destabilizes below 825 °C. This work is concerned with the stabilizing effect of partial B-site substitution in BSCF by Ti (10%) and Nb (5% and 10%). In addition, the effect of B-site substoichiometry on the formation of CoO precipitates as nucleation sites for other secondary phases is studied. The focus of this work is laid on the analysis of the phase constitution in bulk material between 600 and 800 °C. Scanning electron microscopy and (scanning) transmission electron microscopy with high spatial resolution in combination with energy-dispersive X-ray spectroscopy are applied which allow to detect even small volume fractions of secondary phases. It is confirmed by quantitative analysis that Ti and Nb substitution reduces the formation of secondary phases up to ~ 95%. There is a solubility limit of Nb in BSCF, which leads to the precipitation of Nb-rich precipitates already at 5% Nb substitution in contrast to Ti which is fully soluble even at 10% substitution. Despite of that, BSCF doped with 5% Nb in combination with 5% substoichiometric B-site occupation is the most promising material, because it shows the lowest overall volume fraction of secondary phases (~ 0.8 vol% at 700 °C) and an almost negligible degradation rate in additionally recorded long-term resistivity measurements. [ABSTRACT FROM AUTHOR]

As a potential remedy for addressing water scarcity challenges, advanced oxidation processes (AOP) present the opportunity of alleviating the water demand in water scarce regions. In this study appropriate doping of N and Pt into the titanium dioxide (TiO2) lattice using different dendrimers as templates and sources of nitrogen was demonstrated. The resulting N, Pt co‐doped TiO2 with small particle sizes was synthesized through a simple modified sol‐gel method. The N, Pt co‐doped TiO2 photocalysts were characterized through High Resolution Scanning Electron Microscopy (HR‐SEM) coupled with Energy Dispersive Spectroscopy (EDS), Transmission Electron Microscopy (TEM), Brunauer‐Emmett‐Teller  (BET), Raman Spectroscopy (RS), X‐ Ray Diffraction (XRD), Fourier‐transform Infrared Spectroscopy (FTIR), Thermo‐gravimetric analysis (TGA), Ultraviolet and visible (UV‐Vis) absorption spectroscopy  (UV‐Vis) and Photoluminescence (PL). The band gap reduction was more pronounced for the Poly (amidoamine) generation 1 (PAMAM G1) templated N, Pt co‐doped TiO2 (Eg=3.149 eV) compared to Poly (amidoamine) generation 0 (PAMAM G0) and Hyperbranched polyethylenimine (HPEI) templated N, Pt co‐doped TiO2. Co‐doping led to an enhancement in the photocatalytic activity of the photocatalysts for the degradation of brilliant black (99.83%) after 3 hours of visible light irradiation. Therefore, the synthesized photocatalysts can find applications in wastewater treatment using solar light. [ABSTRACT FROM AUTHOR]

We show for the first time that amorphous soda-lime glass undergoes polymorphic transformation to its densest crystalline stishovite phase at only ~5 GPa of pressure and room temperature, by uniaxially compressing the soda-lime glass nanopillars of 500 nm diameter and observing the post-deformed pillars under transmission electron microscopy. This contrasts with the recent shock-compression experiments of amorphous fused silica glass plates which report a pressure threshold of 34 GPa for stishovite formation. Our findings support recent dislocation dynamics simulations on W pillars which show that small domain size acts as a proxy for high temperature, thereby reducing the pressure threshold. Unlabelled Image [ABSTRACT FROM AUTHOR]

The development of low-cost, durable and efficient photocatalyst for overall photoelectrochemical water splitting is in demand to overcome the renewable energy crises. Herein, we demonstrate the efficient photoelectrochemical water splitting by cobalt (Co) incorporated zinc oxide (Zn 1-x Co x O) thin films deposited via aerosol assisted chemical vapour deposition (AACVD) technique. The as-deposited Co incorporated ZnO thin films were characterised by powdered X-ray diffraction (pXRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and ultra violet-visible spectroscopy (UV-Vis). These films with different concentration of cobalt were investigated for water splitting applications and the best results were achieved for the films with 15% Co incorporation. Image 1 [ABSTRACT FROM AUTHOR]

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We report on detailed study of detonation nanodiamonds (DNDs) whose surface has been chemically modified by copper with the aid of ion exchange in water DND suspension. High resolution transmission electron microscopy, Raman, IR, electron magnetic resonance (EMR), nuclear magnetic resonance (NMR), and superconducting quantum interference device techniques were used for the characterization of DND. Carboxyl groups, appearing on the surface of a nanodiamond particle during its synthesis and purification processes, provide an effective binding of divalent copper ions to the surface. The binding results from the ion exchange between metal cations and protons of surface carboxyl groups in water solutions. IR data evidence the presence of multiple C[Single_Bond]O[Single_Bond]C groups in the dried copper-modified DND product. Both EMR and 13C NMR provide direct evidences of the appearance of isolated Cu2+ ions on the surface of the 5 nm nanodiamond particles. EMR spectra reveal well-pronounced hyperfine structure due to 63,65Cu nuclear spin I=3/2 with the spectral pattern which is typical for mononuclear axially distorted Cu2+ complexes in polycrystals. Using Cu2+ ions as paramagnetic probes two-component model of carbon inherited paramagnetic centers in DND is suggested. Magnetic susceptibility for all samples follows the Curie–Weiss law above 30 K. The concentration of magnetically observable copper ions Cu2+ (spin S=1/2) localized on the nanodiamonds surface increases up to approximately 1.5–3.5 ions per nanoparticle with increasing concentration of copper acetate in starting solutions. [ABSTRACT FROM AUTHOR]

Three types of dissociated misfit dislocations (MDs) in epitaxial Ba0.3Sr0.7TiO3 thin films grown on (001) LaAlO3 have been studied by high-resolution transmission electron microscopy. First, a MD with b=[101] dissociates into two edge partials and results in the incline of film lattice. Second, a [110] MD is split into two (1/2)[110] partials of mixed character. In the third case, a [110] MD of mixed character is composed of three partials which are reacted with two (1/2)<110> stacking faults. Neither of the three types of dissociation reactions has been reported before for MDs in perovskite thin films. [ABSTRACT FROM AUTHOR]

Three types of dissociated misfit dislocations (MDs) in epitaxial Ba0.3Sr0.7TiO3 thin films grown on (001) LaAlO3 have been studied by high-resolution transmission electron microscopy. First, a MD with b=[101] dissociates into two edge partials and results in the incline of film lattice. Second, a [110] MD is split into two (1/2)[110] partials of mixed character. In the third case, a [110] MD of mixed character is composed of three partials which are reacted with two (1/2)<110> stacking faults. Neither of the three types of dissociation reactions has been reported before for MDs in perovskite thin films. [ABSTRACT FROM AUTHOR]

Stacked AA graphite has been synthesized using a high-density dc plasma in hydrogen-methane mixtures. Graphene layers have been grown epitaxially with 2-1 registration between the AA graphitic edges and the (111) surface of diamond. In addition, a new graphite crystal structure containing AA′ graphene layers, where alternate planes are translated by half the hexagon width, is formed by 1-1 registry. The resulting interplanar distances of the AA graphite at the interface range from 2.20 Å for the 1-1 registration to 4.40 Å for the 2-1 registration and have been measured directly by high-resolution transmission electron microscopy (TEM). The appearance of the characteristic d-spacings, 3.55, 2.15, 1.80, 1.75 (not fully resolved), and 1.25 Å in the selective area diffraction patterns from the TEM, are consistent with reflections from the (001), (100), (102), (002), and (110) planes of the AA graphite. Simulation of the diffraction patterns, employing the structural factors of graphene, confirms the existence of AA graphite. [ABSTRACT FROM AUTHOR]

We have discovered Raman peculiarities of sp3-bonded carbon nanoclusters forming ultrahard fullerite synthesized at pressure up to 85 GPa. The nanoclusters differ in the values of bulk modulus B 0 ranging from 580 to 730 GPa. We found that the Raman frequency, corresponding to the C-C stretching mode of the nanoclusters, varies linearly from 1485 to 1640 cm−1, depending on the excitation wavelength used, which ranges from 785 nm to 257 nm. In particular, the nanoclusters with higher B 0 have a higher Raman frequency. We also observed a resonant Raman spectrum when excited at a wavelength of 1064 nm. This showed a plateau from 1400 to 1720 cm−1, covering all Raman band positions of the nanoclusters from 1485 to 1640 cm−1. In addition, two Raman bands at 1285 and 1600 cm−1 appear at the resonance. The presence of several types of carbon sp3-bonded nanoclusters is confirmed by high-resolution transmission electron microscopy. Using moment tensor potentials, a class of machine learning interatomic potentials, we calculated the phonon density of states of the nanoclusters formed during the 3D polymerization of C 60. The presence of high frequency modes in the resonant Raman spectra suggests the existence of bonds with force constants higher than those in a single crystal diamond. In addition, we observed a stiffening effect when analyzing the dependence of the mechanical stiffness on the cluster size, with smaller clusters exhibiting a more rigid structure. [Display omitted] [ABSTRACT FROM AUTHOR]

The nanoparticles in a FeCrAl oxide dispersion strengthened (ODS) steel with Ti and Zr addition, i.e., UOC-10 (Fe–15Cr–2W–0.5Ti–7Al–0.4Zr–0.5Y 2 O 3), have been examined by transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). The phases of 134 nanoparticles, which have diameter mainly of 4–11 nm and peak number fraction and, therefore, represent the oxides contributing most significantly to the macroscopic properties of the ODS steel, were identified and, moreover, the proportions of various types of oxides were determined. Relative to FeCrAl-ODS steel without Zr addition, i.e., SOC-9 (Fe–15.5Cr–2W–0.1Ti–4Al–0.35Y 2 O 3), the dispersion morphology and coherency of the oxide nanoparticles in UOC-10 were significantly improved. The nanoparticles in UOC-10 were found to be consistent with δ-phase Y 4 Zr 3 O 12 (∼44.8%), defect fluorite Y 2 Zr 2 O 7 (∼15.7%), perovskite YAlO 3 (YAP) (∼14.2%) and orthorhombic Y 2 TiO 5 (∼11.2%) with distorted perovskite YTiO 3 oxide occasionally detected. Almost all of the nanoparticles are either coherent (∼78.4%) or semi-coherent (∼20.3%) with bcc steel matrix. The crystallographic orientation correlations of the oxides and matrix were determined. The results are compared with those of SOC-9 and SOC-14 (Fe–15Cr–2W–0.1Ti–4Al–0.63Zr–0.35Y 2 O 3) with a brief discussion of the mechanisms of the formation of various kinds of oxides and, moreover, the unusual thermal and irradiation stabilities of the oxides as well as the excellent irradiation tolerance and superior strength of UOC-10. • Oxide morphology of Fe–15Cr–2W–0.5Ti–7Al–0.4Zr–0.5Y 2 O 3 ODS alloy was studied by TEM. • Crystal & interface structures of 134 oxides in it were characterized by HRTEM. • Proportions of various types of oxides were determined according to HRTEM results. • The content ratios of Al/Zr/Ti cause the polymorphic transition of complex oxides. • Mechanisms of thermal and radiation stabilities of the ODS steel were discussed. [ABSTRACT FROM AUTHOR]

Polyaniline (PANI) nanoparticles and PANI/poly vinyl alcohol (PVA) nanocomposite films were synthesized by the oxidative polymerization of aniline and ammonium peroxodisulfate (APS), as an oxidizing agent in aqueous medium. The PANI/PVA nanocomposite films were exposed to γ-irradiation after oxidative polymerization. Synthesized polyaniline (PANI) nanoparticles and PANI/PVA nanocomposite films were characterized by attenuated total reflectance infrared spectroscopy (FTIR-ATR), X-ray diffraction, high resolution scanning electron microscopy, (HRSEM) high resolution transmission electron microscopy, (HRTEM) and UV-VIS absorption spectroscopy. Energy band gap of PANI nanofibers was determined from Tauc's plots which equal 4.2 eV. Scanning electron microscopy images show that chemically synthesized of polyaniline has nanofibers structure and irradiated PANI/PVA nanocomposite have a mixture of nanorod and nanosphere structures. The transmission electron microscopy show that chemically synthesized of polyaniline has average length in the range 34 ± 10 nm with less wide distribution, where as the irradiated PANI/PVA nanocomposite has coreshell structure. [ABSTRACT FROM AUTHOR]

In present work, a highly sensitive biosensor with high selectivity for glucose monitoring is developed based on novel nano-composites of nitrogen doped graphene quantum dots (N-GQDs) and a novel bimetallic Cu/Ni core-shell nanoparticles (CSNPs) (Cu@Ni CSNPs/N-GQDs NCs). With the tuned electronic properties, N-GQDs helped bimetallic core-shell structure nanomaterials from aggregation, and separate the charges generated at the interface. This novel nano-composites also have the good electrical conductivity of N-GQDs, catalyst property of Cu/Ni bimetallic nano composite, Cu@Ni core-shell structure and the synergistic effect of the interaction between bimetallic nano composite and N-GQDs. While modified the electrode with this novel nano-composites, the sensor’ linear range is 0.09 ~ 1 mM, and the limit of detection (LOD) is 1.5 μM (S/N = 3) with a high sensitivity of 660 μA mM-1 cm-2, and rapid response time (3 s). Its’ LOD is more than 74 times lower than the traditional Cu@Ni CSNPs modified working electrode. It also has higher sensitivity and wider linear range. This indicates the great potential of applying this kind of nano composites in electrode modification. [ABSTRACT FROM AUTHOR]

This study presents multiwall and bamboo-like carbon nanotubes found in samples from the Allende carbonaceous chondrite using high-resolution transmission electron microscopy (HRTEM). A highly disordered lattice observed in this material suggests the presence of chiral domains in it. Our results also show amorphous and poorly-graphitized carbon, nanodiamonds, and onion-like fullerenes. The presence of multiwall and bamboo-like carbon nanotubes have important implications for hypotheses that explain how a probable source of asymmetry in carbonaceous chondrites might have contributed to the enantiomeric excess in soluble organics under extraterrestrial scenarios. This is the first study proving the existence of carbon nanotubes in carbonaceous chondrites. [ABSTRACT FROM AUTHOR]

In this paper, the effects of Tb3+ ion concentration on the structural and photoluminescence properties of ZnWO4:Tb3+ have been reported. X-ray diffraction studies indicated that the monoclinic structure of the samples and the crystallinity were found to decrease with the increase of Tb3+ ion concentration due to the distortion in the crystal lattice. The formation of the monoclinic structure was further supported by high resolution transmission electron microscopy and Fourier transform infrared analyses. The transmission electron microscopy image of ZnWO4:Tb3+ (7%) showed a spherical morphology with crystallite sizes in the range of ∼8–12 nm. The excitation spectrum showed a strong broad band originated from the electronic transition within the WO66– group. Upon excitation at 270 nm, the prepared ZnWO4:Tb3+ phosphors exhibited sharp and narrow emission peaks, characteristic of the f–f transitions of Tb3+ ions besides a broad band with the maximum at around 460 nm due to the host lattice. The intensity of the broad emission band was found to decrease gradually with the increase of Tb3+ ion concentration and reached minimum at 7 at%. The decay time of the prepared phosphors was investigated in detail and the maximum average lifetime value is found to be 1.187 ms. [ABSTRACT FROM AUTHOR]

In this study, a series of BUC-21 /titanate nanotube (BT-X) composites were facilely fabricated via ball-milling of 2-dimensional (2D) metal-organic framework (MOF) BUC-21 and titanate nanotubes (TNTs). The BT-X composites were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), UV–visible diffuse-reflectance spectroscopy (UV–vis DRS), X-ray photoelectron spectrometer (XPS) and high resolution transmission electron microscopy (HRTEM). Both the photocatalytic reduction from Cr(VI) to Cr(III) and adsorptive removal of formed Cr(III) of BT-X composites were systematically investigated under different conditions including pH values and co-existing inorganic ions. It was found that BUC-21 (100 mg)/TNTs (100 mg) (BT-1) composites demonstrate remarkable ability of photocatalytic Cr(VI) reduction and adsorptive Cr(III) removal, as well as good reusability and stability. It is believed that the introduction of TNTs could capture the formed Cr(III) from the surface of BUC-21 , which provided more active sites exposed to enhance the Cr(VI) reduction. Image 1 • It was the first time to prepare the MOF/Titanate nanotube composites (BT-X). • BT-1 could achieve photocatalytic Cr(VI) reduction and adsorptive Cr(III) removal. • BT-1 showed good Cr removal activity in wastewater simulated with tap water. • The stable BT-1 could achieve cyclic utilization. [ABSTRACT FROM AUTHOR]

Magnetotactic bacteria biomineralize intracellular magnetic nanocrystals surrounded by a lipid bilayer called magnetosomes. Due to their unique characteristics, magnetite magnetosomes are promising tools in Biomedicine. However, the uptake, persistence, and accumulation of magnetosomes within mammalian cells have not been well studied. Here, the endocytic pathway of magnetite magnetosomes and their effects on human cervix epithelial (HeLa) cells were studied by electron microscopy and high spatial resolution nano-analysis techniques. Transmission electron microscopy of HeLa cells after incubation with purified magnetosomes showed the presence of magnetic nanoparticles inside or outside endosomes within the cell, which suggests different modes of internalization, and that these structures persisted beyond 120 h after internalization. High-resolution transmission electron microscopy and electron energy loss spectra of internalized magnetosome crystals showed no structural or chemical changes in these structures. Although crystal morphology was preserved, iron oxide crystalline particles of approximately 5 nm near internalized magnetosomes suggests that minor degradation of the original mineral structures might occur. Cytotoxicity and microscopy analysis showed that magnetosomes did not result in any apparent effect on HeLa cells viability or morphology. Based on our results, magnetosomes have significant biocompatibility with mammalian cells and thus have great potential in medical, biotechnological applications. [ABSTRACT FROM AUTHOR]

The implantation-induced defects of crystalline silicon implanted with helium ions to a dose of 5 × 10 16 /cm 2 at 600 °C were investigated. The sample was analyzed by transmission electron microscopy and high-resolution electron microscopy. Faceted cavities are observed in the damaged layer. Concurrently the distribution of interstitial-type defect clusters was investigated by conventional electron microscopy in bright and dark field. Many rod-like defects, which belong to {1 1 3}, {1 1 1} and (−2 0 0), are formed in the end of the projected range. In front of the damaged layer, some ribbon-like defects are formed, which belong to 〈2 0 0〉, 〈1 −1 1〉 and 〈1 3 −3〉. The possible reasons of the observed defect clusters are discussed. [ABSTRACT FROM AUTHOR]