Search

Multilayer thin‐film structures in the wings of a butterfly; Papilio crino produce a colourful iridescence from reflected light. In this investigation, scanning electron microscope images show both the concave cover scales and pigmented air‐chamber ground scales. The microstructures with the concavities retroreflect incident light, thus causing the double reflection. This gives rise to both the colour mixing and polarisation conversion clearly depicted in the optical images. The result of the numerical and theoretical analysis via the CIELAB, and optical reflection and transmission of light through the multilayer stacks with the use of transfer method show that the emerging colouration on the Papilio crino is structural and is due to the combination of colours caused by multiple bounces within the concavities. The butterfly wing structure can be used as the template for designing the photonic device. [ABSTRACT FROM AUTHOR]

A characteristic feature of the giant owl butterfly, i.e. Caligo memnon, is its big wing eyespot. This feature could serve as deceiving functionality for the butterfly against predators. As evidenced by scanning electron microscope (SEM) image on black part of eyespot, the scales on wing eyespot contain nanostructured ridges and cross‐ribs. Applying direct measurement, statistical method, and Fourier analysis, the authors evidence that these nanostructures display order–disorder in their shape and position. The autocorrelation of SEM image provides average values of characteristic periods of the order–disorder nanostructures together with an estimation of corresponding correlation lengths. Linecuts obtained from the Fourier transform of SEM image were also analysed with the Hosemann function to extract similar information. These analyses indicate that the nanostructured order–disorder may contribute to blackness on wing eyespot. The authors thus conclude that the blackness on wing eyespot of C. memnon could be attributed to contributions from both the nanostructured order–disorder and melanin pigment. [ABSTRACT FROM AUTHOR]

Mounting‐up economic losses to annual crops yield due to micronutrient deficiency, fertiliser inefficiency and increasing microbial invasions (e.g. Xanthomonas cempestri attack on tomatoes) are needed to be solved via nano‐biotechnology. So keeping this in view, the authors' current study presents the new horizon in the field of nano‐fertiliser with highly nutritive and preservative effect of green fabricated zinc oxide‐nanostructures (ZnO‐NSs) during Lycopersicum esculentum (tomato) growth dynamics. ZnO‐NS prepared via green chemistry possesses highly homogenous crystalline structures well‐characterised through ultraviolet and visible spectroscopy, Fourier transform infrared spectroscopy, X‐ray diffraction and scanning electron microscope. The ZnO‐NS average size was found as small as 18 nm having a crystallite size of 5 nm. L. esculentum were grown in different concentrations of ZnO‐NS to examine the different morphological parameters includes time of seed germination, germination percentage, the number of plant leaves, the height of the plant, average number of branches, days count for flowering and fruiting time period along with fruit quantity. Promising results clearly predict that bio‐fabricated ZnO‐NS at optimum concentration resulted as growth booster and dramatically triggered the plant yield. [ABSTRACT FROM AUTHOR]

The nanostructures on the wings of Idea malabarica (Moore, 1877) were analysed using scanning electron microscopy, energy dispersive X‐ray spectroscopy, atomic force microscopy, Fourier transform‐infrared spectroscopy, and reflectance measurements. The chemical and morphological analyses revealed the chitin‐based intricate nanostructures. The influence of the nanostructures on the wetting characteristics of the wing was investigated using optical imaging. Applying the Maxwell‐Garnet approximation to the porosities within the nanostructures, the refractive indices, which relate the reflectance response, were estimated. It was concluded that the colour seen on the wings of the Idea malabarica originate from the nanostructural configurations of the chitin‐based structures and the embedded pigment. [ABSTRACT FROM AUTHOR]

The transparent wing of the dragonfly Aeshna cyanea has been investigated using scanning electron microscopy (SEM), optical microscopy (OPM), energy‐dispersive X‐ray spectroscopy (EDS) and reflectance spectroscopy. Four cells (D1–D4) were studied and classified according to their general morphology. The OPM depicted the vein‐joint characterised by the distribution of resilin. EDS technique showed common elements such as carbon, oxygen, and chlorine. SEM analysis revealed thin membranes reinforced with a network of hallow veins. Spikes and round shape of microstructures were identified. The roughness of the pruinosity was estimated, which indicates the shape and curvature of the microstructures that essentially play a significant role in the optical response observed. The study can be essential to design and improve micro‐air vehicles. [ABSTRACT FROM AUTHOR]

Aligned and unaligned vanadium (IV) oxide meso-tetraphenyl porphine (VMP)/polyethylene oxide (PEO) hybrid nanofibers have been successfully synthesized by electrospinning technique. The nanofibers were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), atomic force microscopy (AFM), optical microscopy and scanning electron microscopy (SEM). The SEM and AFM analyses of the morphology showed that the nanofibers are cylindrical with diameters ranging from 400-700 nm. The AFM analysis also confirmed that the aligned nanofibers deposited on a small metallic spring are smoother than the unaligned ones deposited on FTO. FTIR analysis showed that the polar environment provided by the phenyl groups of VMP molecules modified the chemical configuration of PEO molecules, and XRD studies indicated that the VMP molecules were homogeneously distributed within the PEO matrix. [ABSTRACT FROM AUTHOR]

High spatial frequency laser induced periodic surface structure (HSFL) morphology induced by femtosecond laser with 230 fs pulse duration, 250 kHz repetition rate at 1030 nm wavelength on CVD diamond surface is investigated and discussed. The spatial modification was characterized and analyzed by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and 2D-Fast Fourier Transform (2D-FFT). We studied the effect of pulse number and laser power on the spatial development of nanostructures, and also deduced the impact of thermal accumulation effect on their morphology. A generalized plasmonic model has been used to follow the optical evolution of the irradiated surface and to determine the periodic value of the nanostructures. We suggest that non-thermal melting and plasmonic excitation are the main processes responsible for the formation of HSFL-type nanostructures. [ABSTRACT FROM AUTHOR]

We report an eco‐friendly synthesis of α‐Cr2O3 nanoparticles (NPs) using Callistemon viminalis (Bottle Brush) flower extracts as an efficient reducing and capping agent. NPs of sizes 15 nm and 17 nm were synthesized by annealing them at 400°C and 500°C, respectively, which were characterized by X‐ray diffraction, UV–Vis, Fourier transform‐infrared, high‐resolution‐transmission electron microscopy/scanning electron microscopy, SAED, energy‐dispersive X‐ray spectroscopy and SQUID. Microplate‐based assay was used for examining antibacterial potential against 12 pathogenic bacterial strains, and their minimum inhibitory concentrations were calculated. MTT cytotoxic assay was accomplished on Leishmania tropica amastigotes and promastigotes, which revealed IC50 values of 44 μg/ml and 10.56 μg/ml, respectively. An IC50 value of 46.32 μg/ml was obtained for HepG2 cancer cells. Enzyme inhibition studies indicated good acetylcholinesterase, moderate butyrylcholinesterase and low alpha‐glucosidase inhibition. Hemolytic assay indicated hemocompatibility at low concentration. In addition, good DPPH radical scavenging and moderate reducing power and total antioxidant potential was revealed by α‐Cr2O3 NPs. [ABSTRACT FROM AUTHOR]

Abstract: The importance of the white photoluminescence (Pl) with multiple emissions for lighting applications also the attractive optoelectronic properties of graphene and nanostructured zinc oxide (ZnO) are universally known. In this work we present an intense Uv visible blue to red luminescence obtained from our synthesized few layered graphene–zinc oxide (FLG–ZnO) based nanostructures prepared via a sol–gel method using ZnO precursors and a FLG solution. Significant blue–green, yellow–orange moreover, red emissions, from FLG–ZnO deposited on a normal glass substrate, generate a clear white luminescence by their recombination and across the entire visible spectrum. While, to investigate the nanostructure of this system, its interaction and the underlying mechanisms of the broadband photoluminescence, UV–VIS spectroscopy, X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) system and photoluminescence spectroscopy (Pl) were used. [Copyright &y& Elsevier]

Abstract Single phase rutile Titanium II Oxide (TiO 2) nanoparticles were successfully synthesized by wet chemical method using Chitin and TiCl 3 as precursor; and the precipitates obtained, dried at 80 °C for 10 min. The as-synthesized rutile phase TiO 2 was characterized by x-ray diffraction, scanning electron microscopy, UV-Vis diffuse reflectance spectroscopy and Fourier transform infrared spectroscopy. The photocatalytic degradation of methylene blue (MB) dye was studied under UV light irradiation using the TiO 2 derived from chitin for different load catalyst. The SEM image and Scherrer calculation using FWHM of the XRD peaks confirmed that the as-synthesized TiO 2 is spherical, highly crystallinity and nanostructured. Highlights • Synthesis of pure phase rutile TiO 2 nanoparticle at low temperature using wet chemical method. • SEM image confirmed the spherical shape of the nanoparticle. • XRD pattern showed it is a single phase crystal structure. • FTIR spectra confirmed the present of Ti-O bending. • Photocatalytic degradation of MB with synthesized TiO 2 degraded to 57% at λ ∼373 nm. [ABSTRACT FROM AUTHOR]

In this study, ZnO nanoparticles were green-synthesized from Acalypha indica leaf extract using zinc acetate as a precursor. The prepared ZnO nanoparticles were calcined at three different temperatures, namely 100, 300, and 600 °C. The structure/morphology of the green-synthesized ZnO nanoparticles was ascertained through X-ray diffraction, particle size analysis, scanning electron microscopy, transmission electron microscopy, and surface area analysis techniques. It was observed from the physico-chemical and biological characterization studies that ZnO nanoparticles calcined at high temperature (600 °C) exhibit high surface area (230 m 2  g −1 ) and small particle size (20 nm) with good antibacterial activity against Escherichia coli (22.89 ± 0.06 mm) and Staphylococcus aureus (24.62 ± 0.08 mm). In addition, cotton fabrics coated with these nanoparticles showed higher UV-protection (87.8 UPF), hydrophobicity (155°), and maximum zone of bacterial inhibition against E. coli and S. aureus (25.13 ± 0.05 mm and 30.17 ± 0.03 mm) than those coated with particles calcined at 100 °C and 300 °C. High temperature calcination has a vital role in the crystallization of the particles towards nanoscale with increased resistivity to UV exposure, washing treatments, and microbial infection in fabrics. Thus, the cost-effective ZnO nanoparticles obtained through green synthesis method proves their potential applications in the field of biomedical, textile, and cosmetic applications. [ABSTRACT FROM AUTHOR]

We used a simple, cost effective and scalable chemical method to deposit mixed oxides of copper and cobalt on indium tin oxide (ITO) and stainless steel (ss) substrates. The deposited mixed oxides of Cu-Co and Co-Cu exhibit uniform surface morphology with nanoporous structure as obtained from scanning electron microscopy (SEM). The electrochemical properties were characterized by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). The Cu-Co oxide film on ITO yielded very high specific and volumetric capacitances of 919 Fg − 1 and 616.1 Fcm − 3 respectively with high energy (28.78 Wh kg − 1 ) and power (51.8 W kg − 1 ) densities. The same oxide on ss yields 195 Fg − 1 and 236.8 Fcm − 3 respectively for the specific and volumetric capacitances. In addition, the Cu-Co oxide electrode shows superior rate capability and excellent long-term cyclability. While the ss offers less internal resistance, the stability of the films is higher on ITO substrates. The bundles of rod-like Cu-Co mixed oxide embedded with nanoporous structure exposed more active surfaces with minimal ion diffusion length thereby enhancing the redox behavior and the binary oxides are synergistically responsible for superior rate capability and excellent durability. Our results indicate that these nanoporous electrodes are promising for use in pseudocapacitive applications. [ABSTRACT FROM AUTHOR]