Showing papers on "Transmission electron microscopy published in 2022"
TL;DR: In this paper , the formation of profuse I2-type solute-enriched stacking faults (SESFs) in fine grains and transformation of SESFs to 18R-long period stacking ordered (LPSO) phase are attained in Mg-Er-Zn-Zr alloys.
71 citations
TL;DR: In this paper , the structural features, magnetic and microwave properties of hard/soft (H/S) SrNi0.02Zr0.01Fe11.96O19 (SrNiZr)/CoFe2O4 (CFO) nanocomposites were investigated.
49 citations
TL;DR: In this paper , the phase transformation sequence of Al-rich zone → θ (D03−Mg3Al) → AlLi was confirmed during anisothermal ageing, and a braided structure resulting from spinodal decomposition was found to be the optimized microstructure for achieving the peak strength.
48 citations
TL;DR: In this article , bimetallic CuO/ZnO nanostructures were biosynthesized using plant extracts and the plant-mediated synthesis nanoparticles were characterized by Transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Energy-Dispersive Spectroscopy (EDAX).
Abstract: Bimetallic nanoparticles offer unique chemical, physical and optical properties that are not available for monometallic nanoparticles. Bimetallic nanoparticles play a major role in various therapeutic, industrial and energy fields. Recently, nanoparticles of Copper/Zinc bimetallic nanoparticles have attracted attention in various fields, especially medicine. In this study, bimetallic CuO/ZnO nanostructures were biosynthesized using plant extracts. The plant-mediated synthesis nanoparticles were characterized by Transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Energy-Dispersive Spectroscopy (EDAX). The cytotoxicity of plant-mediated synthesis bimetallic nanoparticles and the synergistic effects of these nanoparticles in combination with the anticancer drug doxorubicin on MCF-7 cancer cells were evaluated by MTT assay.
46 citations
TL;DR: In this article , the structural properties of AgNPs were systematically studied using X-ray diffraction, high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FT-IR), and Raman measurement, which emanate the single-phase fcc structure of silver nanoparticles.
Abstract: Drug resistance in filamentous fungus to antifungal medicines is a huge problem in biomedical applications; so, an effective strategy for treating opportunistic fungal infections is needed. Mentha piperita is a very fascinating plant to treat a variety of ailments as home remedies. Eighteen strains of Aspergillus species were used for this study which are having a unique antifungal resistance profile in presence of silver nanoparticles (AgNPs). AgNPs were prepared, using an aqueous extract of M. Piperita and characterized it by various techniques. Structural properties of AgNPs were systematically studied using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), Fourier-transform infrared spectroscopy (FT-IR), and Raman measurement, which emanate the single-phase fcc structure of silver nanoparticles. The spherical nature and elemental analysis of as-synthesized AgNPs were confirmed using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) spectroscopy, respectively. The optical study has been analyzed using UV-Vis spectroscopy and band gap was calculated as 2.51 eV, using Tauc plot. To analyze and validate the good efficacy of the disc approach, antifungal activity of AgNPs nanoparticles in different concentrations against isolates was achieved in both disc and broth microdilution. The extracellular enzymatic activity of A. fumigatus was found to explore the precise impact of nanoparticles on fungal metabolism. The antifungal efficacy of AgNPs against all fungi was highly successful in disc method. The broth approach underlined the favorable results of the disc method. It provided more precise results in determining the minimum inhibition concentration (MIC), as well as the minimum effective concentration (MEC). A. fumigatus (AM6) enzymatic activity was boosted by AgNPs. Also, ß-galactosidase, ß-glucuronidase, and ß-glucosidase are necessary enzymes whose activity has been boosted. Consequently, M. piperita AgNPs can play a major and intriguing function against resistant Aspergillus species with a significant shift in the enzymatic activity profile of fungi due to this action.
45 citations
TL;DR: In this paper , a low-cost, green synthesis of AgNPs utilizing using Kei-apple (Dovyalis caffra) fruit extract was provided. But, the authors did not consider the safety of green fabrication.
44 citations
TL;DR: In this paper , the authors used Calotropis procera mediated synthesis of copper oxide nanoparticles (CuONPs) using aqueous plant extract and their anti-pathogenic activities against phytopathogens.
43 citations
TL;DR: In this paper , a reversible transition between polar Pbc21 and antipolar Pbca phases, where the crystal structures of the 180° domain wall and the unit cell structure were identical, was induced by applying appropriate cycling voltages.
Abstract: Atomic-resolution Cs-corrected scanning transmission electron microscopy revealed local shifting of two oxygen positions (OI and OII) within the unit cells of a ferroelectric (Hf0.5Zr0.5)O2 thin film. A reversible transition between the polar Pbc21 and antipolar Pbca phases, where the crystal structures of the 180° domain wall of the Pbc21 phase and the unit cell structure of the Pbca phase were identical, was induced by applying appropriate cycling voltages. The critical field strength that determined whether the film would be woken up or fatigued was ~0.8 MV/cm, above or below which wake-up or fatigue was observed, respectively. Repeated cycling with sufficiently high voltages led to development of the interfacial nonpolar P42/nmc phase, which induced fatigue through the depolarizing field effect. The fatigued film could be rejuvenated by applying a slightly higher voltage, indicating that these transitions were reversible. These mechanisms are radically different from those of conventional ferroelectrics.
41 citations
01 Mar 2022
TL;DR: In this paper , the gold-loaded tellurium ([email protected]) nanobelts are synthesized through a one-pot hydrothermal process, and the formation of gold-like gold nanoparticles with a typical thickness of 18 nm is confirmed.
Abstract: NO2 is one of the recognized six major pollutants worldwide. Its monitoring and forewarning are indispensable for human health. Thus, a practical sensor with rapid response and high sensitivity would endow us with an effective acknowledgment of NO2 distribution. In this work, the gold-loaded tellurium ([email protected]) nanobelts are synthesized through a one-pot hydrothermal process. According to various characterization, including X-ray diffraction, atomic force microscope, transmission electron microscopy, the formation of tellurium nanobelts with a typical thickness of 18 nm and flower-like gold nanoparticles with a diameter of 50–200 nm is confirmed. Based on these, the [email protected] sensor exhibits appealing sensing properties in a comprehensive measurement considering the practical application scenarios, including a sensitivity of 0.028 ppb-1 (0–50 ppb), a limit of detection with ppt-level (~83 ppt), rapid response (11.3 s towards 5 ppm), good repeatability and selectivity. Meanwhile, the long-term stability is measured under continuous charging in accordance with actual application scenarios. A stable response along 28 days is observed. This work provides an efficient strategy for the fabrication of NO2 sensors, together with a case for gas sensor evaluation towards specified application scenarios.
37 citations
TL;DR: In this article , a chitosan/hollow g-C3N4/curcumin (CS-HCNS-Cur) biocomposite films was successful fabricated with integrated functions of slow release, antimicrobial activity and food freshness preservation.
34 citations
TL;DR: In this article, a chitosan/hollow g-C3N4/curcumin (CS-HCNS-Cur) biocomposite films was successful fabricated with integrated functions of slow release, antimicrobial activity and food freshness preservation.
TL;DR: In this article , a soft template method was used to detect low concentrations of volatile organic compounds (VOCs) for the early diagnosis of lung cancer, sensors based on hollow spheres of In 2 O 3 were prepared through the soft template technique.
Abstract: Abstract In order to detect low concentrations of volatile organic compounds (VOCs) for the early diagnosis of lung cancer, sensors based on hollow spheres of In 2 O 3 were prepared through the soft template method. Ag nanoparticle decorated In 2 O 3 composites were synthesized via dipping and annealing. The microstructure, phase composition, element distribution, and state of Ag were analyzed by the scanning electron microscopy (SEM), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS). The gas sensing tests showed that Ag-In 2 O 3 sensors had the highest response to isopropanol at 300 °C. The best response of Ag-In 2 O 3 composite sensor was 5.2, which had a significant improvement compared with only In 2 O 3 . Moreover, the response and recovery time of Ag-In 2 O 3 composite sensor was significantly shortened. The improved sensing properties of Ag-In 2 O 3 composite sensor could be attributed to the Schottky barrier created at Ag-In 2 O 3 interface and catalytical effect of Ag.
TL;DR: In this paper , the advantages of photocatalysis and membrane technology have been coupled to resolve the issue of membrane fouling without any compromise on separation characteristics, and a novel g-C3N4@MXene/PES (CN-MX) photocatalytic composite membrane through vacuum filtration for wastewater treatment.
TL;DR: In this article , the atomic-level structure of biomacromolecules-metal-organic frameworks (BMOFs) was identified using differential phase contrast-scanning transmission electron microscopy, cryo-electron microscopy and x-ray absorption fine structure techniques.
Abstract: Crystallization of biomacromolecules-metal-organic frameworks (BMOFs) allows for orderly assemble of symbiotic hybrids with desirable biological and chemical functions in one voxel. The structure-activity relationship of this symbiotic crystal, however, is still blurred. Here, we directly identify the atomic-level structure of BMOFs, using the integrated differential phase contrast-scanning transmission electron microscopy, cryo-electron microscopy and x-ray absorption fine structure techniques. We discover an obvious difference in the nanoarchitecture of BMOFs under different crystallization pathways that was previously not seen. In addition, we find the nanoarchitecture significantly affects the bioactivity of the BMOFs. This work gives an important insight into the structure-activity relationship of BMOFs synthesized in different scenarios, and may act as a guide to engineer next-generation materials with excellent biological and chemical functions.
TL;DR: In this paper , the dynamics of laser-induced cavitation bubbles (LICBs) during pulsed laser ablation (PLA) of a nickel target in different solvents was investigated by measuring the time-resolved formation of LICBs utilizing an intensified charge-coupled device (ICCD) camera.
TL;DR: In this article , a heterostructured porous carbon framework (PCF) composed of reduced graphene oxide (rGO) nanosheets and metal organic framework (MOF)-derived microporous carbon is prepared to investigate its potential use in a lithium-ion battery.
TL;DR: In this article , the hierarchical morphology and composition of Ni-Co-P hollow nanobricks were respectively characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), nitrogen sorption analysis and transmission electron microscope (TEM).
Abstract: Metal phosphide has been widely exploited in the field of energy storage and catalysis instead of chemical sensors. In this work, Ni-Co-P hollow nanobricks (HNBs) was developed via template synthesis method followed by etching and phosphating treatments. The hierarchical morphology and composition of the Ni-Co-P HNBs were respectively characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), nitrogen sorption analysis and transmission electron microscopy (TEM). High sensitivity (~ 3.6 kΩ / % RH), low hysteresis (~ 3% RH) and good repeatability were achieved in a wide moisture range from 0% RH to 97.5% RH. By adjusting the ratio of Ni and Co, humidity sensing performance can be efficiently modulated. The optimal humidity sensing properties were attained at a ratio of Ni and Co of 1:5. Finally, the as-prepared sensor demonstrates great capability in respiratory analysis and noncontact human-machine interfacing. This work opens up a new paradigm for developing high-performance wearable sensing devices.
TL;DR: In this paper , the atomic-level structure of biomacromolecules-metal-organic frameworks (BMOFs) was identified using differential phase contrast-scanning transmission electron microscopy, cryo-electron microscopy and x-ray absorption fine structure techniques.
Abstract: Crystallization of biomacromolecules-metal-organic frameworks (BMOFs) allows for orderly assemble of symbiotic hybrids with desirable biological and chemical functions in one voxel. The structure-activity relationship of this symbiotic crystal, however, is still blurred. Here, we directly identify the atomic-level structure of BMOFs, using the integrated differential phase contrast-scanning transmission electron microscopy, cryo-electron microscopy and x-ray absorption fine structure techniques. We discover an obvious difference in the nanoarchitecture of BMOFs under different crystallization pathways that was previously not seen. In addition, we find the nanoarchitecture significantly affects the bioactivity of the BMOFs. This work gives an important insight into the structure-activity relationship of BMOFs synthesized in different scenarios, and may act as a guide to engineer next-generation materials with excellent biological and chemical functions.
TL;DR: In this paper , a detailed summary of the synthesis, characterization and applications of unoped and (Ag, Fe) co-doped CuO NPs with a diverse concentration of Fe (0.02, 0.06 and 0.08 M).
Abstract: Nanoparticles (NPs) are miniature materials ranging from 1 to 100 nm. The NPs have unique chemical and physical properties due to their shape, size and high surface area. This research paper gives a detailed summary of the synthesis, characterization and applications of undoped and (Ag, Fe) co-doped CuO NPs with a diverse concentration of Fe (0.02, 0.04, 0.06 and 0.08 M) at a constant concentration of Ag (0.02 M). X-ray diffractometer (XRD) results revealed average crystallite size of NPs varies in the range 13.10-24.98 nm. Scanning electron microscopy (FE-SEM) showed that the morphology of pure synthesized CuO NPs and Energy dispersive x-ray spectroscopy (EDX) recognized the presence of Ag, Fe elements in the CuO lattice. The particle size obtained by transmission electron microscope (HR-TEM) images was found in the range 19.73-21.47 nm. Cu-O bond stretching of NPs was also confirmed by Fourier Transform Infrared (FTIR) techniques. The values of direct and indirect band gap for CuO were found to be 1.41-1.54 eV and 0.69-1.51 eV respectively. Antibacterial activity for synthesized NPs tested against gram-negative and gram-positive pathogenic bacteria. The photocatalytic properties of synthesized NPs were investigated by monitoring the methyl orange/methylene blue degradation in ultraviolet visible spectroscopy (UV-Vis).
TL;DR: The in vitro wound-healing model revealed that the Chi/AuNP dressing provides a relatively rapid and efficacious wound- healing ability, making the obtained nanocomposite a promising candidate for the development of improved bandage materials.
Abstract: The global spread of multidrug-resistant bacteria has become a significant hazard to public health, and more effective antibacterial agents are required. Therefore, this study describes the preparation, characterization, and evaluation of gold nanoparticles modified with chitosan (Chi/AuNPs) as a reducing and stabilizing agent with efficient antimicrobial effects. In recent years, the development of an efficient and ecofriendly method for synthesizing metal nanoparticles has attracted a lot of interest in the field of nanotechnology. Colloidal gold nanoparticles (AuNPs) were prepared by the chemical reduction of gold ions in the presence of chitosan (Chi), giving Chi/AuNPs. The characterization of Chi/AuNPs was carried out by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR), and X-ray diffraction (XRD). Chi/AuNPs appeared spherical and monodispersed, with a diameter ranging between 20 to 120 nm. The synergistic effects of AuNPs and Chi led to the disruption of bacterial membranes. The maximum inhibitory impact was seen against P. aeruginosa at 500 µg/mL, with a zone of inhibition diameter of 26 ± 1.8 mm, whereas the least inhibitory effect was reported for S. aureus, with a zone of inhibition diameter of 16 ± 2.1 mm at the highest dose tested. Moreover, Chi/AuNPs exhibited antifungal activity toward Candida albicans when the MIC was 62.5 µg/mL. Cell viability and proliferation of the developed nanocomposite were evaluated using a sulphorhodamine B (SRB) assay with a half inhibitory concentration (IC50) of 111.1 µg/mL. Moreover, the in vitro wound-healing model revealed that the Chi/AuNP dressing provides a relatively rapid and efficacious wound-healing ability, making the obtained nanocomposite a promising candidate for the development of improved bandage materials.
TL;DR: In this paper , a novel sonochemical synthesis pathway of sub-15 nm silver nanoparticles (AgNPs) with quasi-spherical shape and high stability in aqueous suspension is presented.
Abstract: The present study shows the development of a novel sonochemical synthesis pathway of sub-15 nm silver nanoparticles (AgNPs) with quasi-spherical shape and high stability in aqueous suspension. Different analytical techniques such as on-line UV-Vis spectroscopy, Atomic Force Microscopy (AFM), and Transmission Electron Microscopy (TEM) were complementarily used to characterize the evolution of the properties of AgNPs synthesized with this new route. Furthermore, different centrifugation conditions were studied to establish a practical, simple and straightforward purification method. Particle size was determined by TEM employing two different deposition methods, showing that purified AgNPs have a size of 8.1 nm ± 2.4 nm with a narrow dispersion of the size distribution (95% coverage interval from 3.4 to 13 nm). Critical information of the shape and crystalline structure of these sub-15 nm AgNPs, provided by shape descriptors (circularity and roundness) using TEM and high resolution (HR)-TEM measurements, confirmed the generation of AgNPs with quasi-spherical shapes with certain twin-fault particles promoted by the high energy of the ultrasonic treatment. Elemental analysis by TEM-EDS confirmed the high purity of the sub-15 nm AgNPs, consisting solely of Ag. At the optical level, these AgNPs showed a bandgap energy of (2.795 ± 0.002) eV. Finally, the evaluation of the effects of ultraviolet radiation (UVC: 254 nm and UVA: 365 nm) and storage temperature on the spectral stability revealed high stability of the optical properties and subsequently dimensional properties of sub-15 nm AgNPs in the short-term (600 min) and long-term (24 weeks).
TL;DR: In this paper, the thermal stability of different microstructures tailored by various cooling approaches were investigated utilizing scanning electron microscope, electron backscattered diffraction, transmission electron microscope and X-ray diffraction line profile analysis.
TL;DR: In this paper , the thermal stability of different microstructures tailored by various cooling approaches were investigated utilizing scanning electron microscope, electron backscattered diffraction, transmission electron microscope and X-ray diffraction line profile analysis.
TL;DR: In this article, the piezoelectric effect improved heterogeneous photocatalysis of g-C3N4/Ag/ZnO (g-CN/A/Z) tricomponent in rhodomine B degradation.
TL;DR: In this paper, in-situ electrochemical impedance spectroscopy (EIS) test is performed on the whole discharge process of Si@Graphite@C/Li cell at 0, 25 and 55 ℃, respectively.
TL;DR: In this article , the piezoelectric effect improved heterogeneous photocatalysis of g-C3N4/Ag/ZnO (g-CN/A/Z) tricomponent in rhodomine B degradation.
TL;DR: In this article , the authors developed a novel ultrathin fibrous membrane with a core-sheath structure as antibacterial food packaging film, by exploiting coaxial electrospinning to create the core sheath structure, by which the delivery regulation of the active substance was achieved.
Abstract: The purpose of this work is to develop a novel ultrathin fibrous membrane with a core-sheath structure as antibacterial food packaging film. Coaxial electrospinning was exploited to create the core-sheath structure, by which the delivery regulation of the active substance was achieved. Resveratrol (RE) and silver nanoparticles (AgNPs) were loaded into electrospun zein/polyethylene oxide ultrathin fibers to ensure a synergistic antibacterial performance. Under the assessments of a scanning electron microscope and transmission electron microscope, the ultrathin fiber was demonstrated to have a fine linear morphology, smooth surface and obvious core-sheath structure. X-ray diffraction and Fourier transform infrared analyses showed that RE and AgNPs coexisted in the ultrathin fibers and had good compatibility with the polymeric matrices. The water contact angle experiments were conducted to evaluate the hydrophilicity and hygroscopicity of the fibers. In vitro dissolution tests revealed that RE was released in a sustained manner. In the antibacterial experiments against Staphylococcus aureus and Escherichia coli, the diameters of the inhibition zone of the fiber were 8.89 ± 0.09 mm and 7.26 ± 0.10 mm, respectively. Finally, cherry tomatoes were selected as the packaging object and packed with fiber films. In a practical application, the fiber films effectively reduced the bacteria and decreased the quality loss of cherry tomatoes, thereby prolonging the fresh-keeping period of cherry tomatoes to 12 days. Following the protocols reported here, many new food packaging films can be similarly developed in the future.
TL;DR: In this article , in-situ electrochemical impedance spectroscopy (EIS) test is performed on the whole discharge process of [email protected]@C/Li cell at 0, 25 and 55 ℃, respectively.
TL;DR: In this paper, the electrochemical performance of linuron (LNR) was studied by fabricating the carbon paste electrode (CPE) using multiwalled carbon nanotubes (MWCNTs) along with zinc oxide (ZnO) nanoparticles (MWCNTs/ZnOs/CPE).