Sharp Diffraction Peak Research Articles

Anti-cancer applications of Zr, Co, Ni-doped ZnO thin nanoplates

Nanostructured zinc oxide received much attention with its distinctive properties. Undoped and doped ZnO formation by hydrothermal route was summarized. ZnO hexagonal structure was confirmed by sharp X-ray diffraction peak corresponding to crystalline plane (101), and doped ZnO diffraction peaks have a minor shift to inferior angle by 0.6˚. FTIR confirmed Zn-O vibration band observed at 422 cm−1. The doping concentration played a vital role in materials morphology and optical properties. SEM confirmed the existence of thin uniform nanoplate surface morphology. ZnO oxygen vacancies were revealed by PL spectra, which exhibited a chief role in anticancer mechanism and activity with green emission (491 nm, 2.52 eV) originated from electrons shift between ionized oxygen vacancy and valence band. Prepared ZnO with and without dopants have been explored to reveal anticancer applications, and obtained results are more suitable for real-time applications.

The Manufacture of GaN Powder in Plasma

In this paper, the preparation technology of GaN powder has been studied by using of plasma powder synthesis system, and several properties were improved such as: the morphology, the particle size, structure and optical properties. The result shows that, by applying for plasma method, high purity GaN powder was manufactured; the GaN has a good morphology and a regular spherical shape. The spherical ratio of the GaN powder was more than 95%; The GaN powder can be adjusted with different process parameters to achieve particle size control; The GaN powder has sharp diffraction peak and good crystallinity; The GaN powder has the structure of wurtzite and good luminescent properties.

Characterization and electrical enhancement of PVP/PVA matrix doped by gold nanoparticles prepared by laser ablation

In this study, Polyvinyl Pyrrolidone (PVP)/Polyvinyl Alcohol (PVA) blend embedded by gold nanoparticles (AuNPs) was synthesized via traditional casting method to study the enhanced electrical conductivity of the blend. AuNPs were synthesized by Laser Ablation in Liquids Technique (PLAL). The physical characterization of the prepared PVP/PVA/AuNPs films have been performed by various techniques. The electrical conductivity of the prepared samples was evaluated. The structural characterization shows significant sharp diffraction peak at 2 theta = 38° attributed to the plane (111) related to the presence of AuNPs. UV–Vis absorption spectra reveals the distinctive peak of AuNPs at 536 nm. SEM diffractograms approve the embedding of AuNPs in the surface of PVP/PVA. The electrical conductivity data approved enhancement the performance of the pure blend PVP/PVA after embedded with AuNPs prepared by laser ablation. Ac conductivity have been increased by increasing the ratio of AuNPs within PVP/PVA blend. Thus, these observations reflect the use of PVP/PVA/AuNPs samples in electrical applications.

Enhancement in structural, morphological and optical features of thermally annealed zinc oxide nanofilm

This paper presents the study of surface morphological, optical and microstructural features of zinc oxide (ZnO) nanofilm layered upon p-type Si substrate of <100> orientation by employing conventional RF magnetron sputtering system at different annealing temperatures. The effect of annealing on the nano-film is examined using different characterization techniques such as Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), FTIR (Fourier Transform Infrared Spectroscopy), UV-vis spectroscopy and Raman spectroscopy. The sharp diffraction peak at (002) orientation is seen by the XRD spectra which signifies a better growth of single crystalline thin film along the z-axis with the hexagonal wurtzite crystal structure. The surface morphological study shows that the grain size of the thin film intensifies from 22.06 nm to 36.77 nm when the annealing temperature is increased whereas there is a decrease in the values of lattice constants (a=b, c), FWHM (full width at half maximum), residual stress, lattice strain and dislocation density by increasing annealing temperature. The enhancement in the grain size makes the thin film appropriate for MEMS device applications including piezoelectric energy harvesters, gas sensors, etc. The optical bandgap of the ZnO thin film is estimated using Kubelka-Munk (KM) approach and it decreases from 3.23 to 3.16 eV for As-deposited, 400 °C, 600 °C and 800 °C respectively which makes the annealed thin film apposite for optoelectronic device applications. The intensity of the Raman peaks strengthens with the annealing temperature. These results prove that the annealing extensively enhances the crystallinity, structural, morphological and optical features of ZnO thin film and hence becomes suitable for nanoelectronic device applications.

SEM-Drude Model for the Accurate and Efficient Simulation of MgCl2-KCl Mixtures in the Condensed Phase.

There is a long history of models that to different extents reproduce structural and dynamical properties of high-temperature molten salts. Whereas rigid ion models can work fairly well for some of the monovalent salts, polarizability is fundamentally important when small divalent or multivalent cations are combined with significantly polarizable anions such as Cl- to form networked liquids that display a first sharp diffraction peak. There are excellent polarizable ion models (PIMs) for these systems, but there has been little success with the less expensive Core-Shell type models, which are often described as unwieldy or difficult to fit. In this article, we present the Sharma-Emerson-Margulis (SEM)-Drude model for MgCl2/KCl mixtures that with the same ingredients used in the latest and most accurate PIM models overcome the aforementioned obstacles at significantly less computational cost; structural and dynamical properties are for all practical purposes very similar to what we obtain from the PIM but typical simulations can be more than 30 times faster. This has allowed us not only to expand our recent studies on the temperature and composition dependence of intermediate range order in MgCl2/KCl mixtures but also to access transport properties that were simply too costly to properly sample in our recently published studies.

On the presence of nanoscale heterogeneity in Al70Ni15Co15 metallic glass under pressure

We used molecular dynamics simulations to investigate the dependence of the atomic-scale structure on the temperature and pressure conditions of Al70Ni15Co15 metallic glass. The effect of pressure variations on the glass transition temperature was also studied, showing an increase with pressure. Moreover, radial distribution function, coordination number, and Voronoi tessellation analysis indicate that the applied pressure affects the local structure of glassy Al70Ni15Co15. We used a local symmetry parameter to access the glass-forming ability of the metallic glasses cooled under different pressures. The glasses cooled under high-pressures showed a significant fraction of embedded crystalline structure, which was found to be surrounded by a region of mixed-like clusters playing the role of an interface between the crystalline region and the glassy region. The correlation length, as calculated from the full width at half maximum of the first sharp diffraction peak, indicated an increase of the medium-range order with the increase of pressure. The evolution of the heterogeneity with pressure was highlighted by the existence of nanoscale crystals (1 to 4 nm in size)embedded in the amorphous zone. Finally, we discuss the results by referring to the atomic potential energy and stress.

Physical and optical studies of the novel non-crystalline CuxGe20-xSe40Te40 bulk glasses and thin films

In this research work, the authors devoted their efforts to study the physical and optical properties of the novel CuxGe20-xSe40Te40, CGST (x = 0,5,10,15,20 at.%) matrix. Physical properties of bulk samples and optical properties of thin films of this matrix have been studied. The bulk glassy samples were prepared using the known melt quenching method, while thin-film samples were deposited by vacuum deposition technique under pressure 10−4 Pa. X-ray diffraction examination showed that thin-film samples were deposited in the amorphous state, where no discrete sharp diffraction peaks were formed. Energy-dispersive X-ray spectroscopy exhibited also that there is a good agreement between the experimental results and the selected elemental composition ratios for all samples. The optical properties were studied using the spectrophotometric measurements of transmittance and reflectance spectra within the spectral range 300 nm–2500 nm. The absorption coefficient, the absorption index, optical energy gap, Urbach energy and others have been investigated and discussed on the view of the chemical band approach model. The optical energy gap decreases from 1.208 eV to 1.045 eV, while Urbach energy increases from 0.186 eV to 0.219 eV as Cu ratio increased from zero to 20%. These CGST samples showed very low absorbance nature in the NIR and IR regions. Therefore, they can be used in the applications of optoelectronics devices, infrared imaging, and optical filters and detectors.

Synthesis of magnesium nitride films with BN as protective layers by reactive radio-frequency magnetron sputtering

Magnesium nitride films were synthesized on silicon substrates by reactive radio-frequency magnetron sputtering (13.56 MHz) with a high-purity magnesium target and nitrogen as the working gas. The effects of the sputtering power and the growth temperature on the qualities of Mg3N2 films were investigated. As for Mg3N2 films synthesized at 773 K for 2 h with the sputtering power of 200 W, the intense Raman peak at 381 cm-1 with the Full width at half maximum of 8.3 cm-1 and the sharp X-Ray Diffraction peak of Mg3N2 (222) at 2θ=31.1° were observed, and the ultraviolet-visible absorption spectra showed that the prepared Mg3N2 films have the intrinsic absorption edges of about 480 nm and the optical bandgap of 2.62 eV. Moreover, it was demonstrated that Boron nitride films can be used as not only protective layers to effectively prevent Mg3N2 films from being hydrolyzed, but also good optical windows.

Gold nanoparticles doped Polyvinyl Alcohol/Chitosan blend via laser ablation for electrical conductivity enhancement

Blend of Polyvinyl Alcohol (PVA) and Chitosan (CS) doped by various concentrations of gold nanoparticles were prepared via one-pot laser ablation route to improve the performance of electrical conductivity of PVA/CS. The physical properties of the synthesized PVA/CS/AuNPs were analyzed via XRD, UV–Visible, and FE-SEM. The electrical conductivity of PVA/CS/AuNPs films has been analyzed. The influences of the various laser ablation times for production of gold nanoparticles that have been doped in PVA/CS blend on the characterizations of the synthesized samples have been obtained via several techniques. XRD shows sharp diffraction peak at 2θ = 38° related to gold nanoparticles that approved the interaction between PVA/CS and gold nanoparticles. According our results, it was show a presence of the characteristic peak of SPR of AuNPs in the UV–Vis absorption spectra at about 536 nm. AC conductivity has been increased as the concentration of AuNPs increased in PVA/CS matrix leading its suggestion for electrical applications.

Indentation-Induced Structural Changes in Vitreous Silica Probed by in-situ Small-Angle X-Ray Scattering

The transient (or permanent) structural modifications which occur during local deformation of oxide glasses are typically studied on the basis of short-range data, for example, obtained through vibrational spectroscopy. This is in contrast to macroscopic observations, where variations in material density can usually not be explained using next-neighbor correlations alone. Recent experiments employing low-frequency Raman spectroscopy have pointed-out this issue, emphasizing that the deformation behavior of glasses is mediated through structural heterogeneity and drawing an analogy to granular media. Here, we provide additional support to this understanding, using an alternative experimental method. Structural modification of vitreous silica in the stress field of a sharp diamond indenter tip was monitored by in-situ small-angle X-ray scattering. The influenced zone during loading and after unloading was compared, demonstrating that changes in the position of the first sharp diffraction peak (FSDP) directly in the center of the indent are of permanent character. On the other hand, variations in the amplitude of electron density fluctuations appear to fully recover after load release. The lateral extent of the modifications and their relaxation are related to the short- to intermediate-range structure and elastic heterogeneity pertinent to the glass network. With support from Finite Element Analysis, we suggest that different structural length scales govern shear and isotropic compaction in vitreous silica.

Nanometric Fluctuations of Sound Velocity in Alkali Borate Glasses and Fragility of Respective Melts

The network structure of borate glass is remarkably modified by the addition of alkali metals. The alkali metal dependences of the first sharp diffraction peak (FSDP) and the boson peak (BP) are investigated in alkali borate glasses by elastic and inelastic neutron scattering experiments. With an increase in ionic radius of alkali ions, both the width ΔQ of FSDP and the BP energy decrease. The comparison of the characteristic length of medium‐range order (MRO) predicted by the FSDP and the position of the BP allows us to find the mean‐square fluctuations of the transverse sound velocity within series of alkali borate glasses. It is shown that the fragility of the respective alkali borate melts inversely correlates with the mean‐square fluctuations of the transverse sound velocity in glassy state.

A High-Throughput Structural and Electrochemical Study of Metallic Glass Formation in Ni-Ti-Al.

On the basis of a set of machine learning predictions of glass formation in the Ni-Ti-Al system, we have undertaken a high-throughput experimental study of that system. We utilized rapid synthesis followed by high-throughput structural and electrochemical characterization. Using this dual-modality approach, we are able to better classify the amorphous portion of the library, which we found to be the portion with a full width at half maximum (fwhm) of >0.42 Å-1 for the first sharp X-ray diffraction peak. Proper phase labeling is important for future machine learning efforts. We demonstrate that the fwhm and corrosion resistance are correlated but that, while chemistry still plays a role in corrosion resistance, a large fwhm, attributed to a glassy phase, is necessary for the highest corrosion resistance.

Very sharp diffraction peak in nonglass-forming liquid with the formation of distorted tetraclusters

Understanding the liquid structure provides information that is crucial to uncovering the nature of the glass-liquid transition. We apply an aerodynamic levitation technique and high-energy X-rays to liquid (l)-Er2O3 to discover its structure. The sample densities are measured by electrostatic levitation at the International Space Station. Liquid Er2O3 displays a very sharp diffraction peak (principal peak). Applying a combined reverse Monte Carlo – molecular dynamics approach, the simulations produce an Er–O coordination number of 6.1, which is comparable to that of another nonglass-forming liquid, l-ZrO2. The atomic structure of l-Er2O3 comprises distorted OEr4 tetraclusters in nearly linear arrangements, as manifested by a prominent peak observed at ~180° in the Er–O–Er bond angle distribution. This structural feature gives rise to long periodicity corresponding to the sharp principal peak in the X-ray diffraction data. A persistent homology analysis suggests that l-Er2O3 is homologically similar to the crystalline phase. Moreover, electronic structure calculations show that l-Er2O3 has a modest band gap of 0.6 eV that is significantly reduced from the crystalline phase due to the tetracluster distortions. The estimated viscosity is very low above the melting point for l-ZrO2, and the material can be described as an extremely fragile liquid.

Preparation and Characterization of Nano-Hydroxyapatite Particles and Chitosan by Sol–Gel Method (in Vitro Study)

Successful osseointegration of dental implants depends on many factors, including implant stability, bone quality, implant surface condition, and implant materials. Implant surface is coated using different techniques to enhance osseointegration. Sol–gel technique is one of the modern and easy techniques in the production of more bioactive hydroxyapatite (HA). In this study, nano-HA and chitosan were used to coat titanium disc via the sol–gel technique. Materials and Method: The nano-HA/chitosan composite was prepared using calcium nitride and phosphorus pentoxide solutions. The solutions were drop wisely mixed on a magnetic stirrer. Then, 3 mg of chitosan was added to the mixture, and the mixture was stirred for 15 h. Titanium samples were dip coated in the mixture of chitosan/HA on the stirrer at slow speed for 90 min to precipitate the coating layer. Afterward, the samples were removed and dried in a hot air oven. They were sintered at 400 °C for 1 h. X-ray diffraction (XRD), light microscopy, scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), FTIR analysis, and atomic force microscopy (AFM) were used to analyze the surface and thickness. The results of XRD test showed that HA particles had sharp diffraction peaks, indicating high crystallinity of the structure due to the sol–gel preparation. Results of optical light microscopy showed that the coated layer was fairly distributed on titanium samples. SEM results of the coated samples showed different surface features, which present a roughness with the appearance of a crystal pool with irregular accumulation of small, spherical-like granules. EDX analysis showed the presence of ions that comprised HA. AFM analysis of the coated sample indicated peaks and projections with average surface nano-roughness (10.1 nm) and grain size (2022–2057 nm). FTIR analysis showed the presence of a band associated with HA particles and amide groups associated with chitosan. The average of thickness readings was 60 ?m.

Accurate high-resolution single-crystal diffraction data from a Pilatus3 X CdTe detector.

Hybrid photon-counting detectors are widely established at third-generation synchrotron facilities and the specifications of the Pilatus3 X CdTe were quickly recognized as highly promising in charge-density investigations. This is mainly attributable to the detection efficiency in the high-energy X-ray regime, in combination with a dynamic range and noise level that should overcome the perpetual problem of detecting strong and weak data simultaneously. These benefits, however, come at the expense of a persistent problem for high diffracted beam flux, which is particularly problematic in single-crystal diffraction of materials with strong scattering power and sharp diffraction peaks. Here, an in-depth examination of data collected on an inorganic material, FeSb2, and an organic semiconductor, rubrene, revealed systematic differences in strong intensities for different incoming beam fluxes, and the implemented detector intensity corrections were found to be inadequate. Only significant beam attenuation for the collection of strong reflections was able to circumvent this systematic error. All data were collected on a bending-magnet beamline at a third-generation synchrotron radiation facility, so undulator and wiggler beamlines and fourth-generation synchrotrons will be even more prone to this error. On the other hand, the low background now allows for an accurate measurement of very weak intensities, and it is shown that it is possible to extract structure factors of exceptional quality using standard crystallographic software for data processing (SAINT-Plus, SADABS and SORTAV), although special attention has to be paid to the estimation of the background. This study resulted in electron-density models of substantially higher accuracy and precision compared with a previous investigation, thus for the first time fulfilling the promise of photon-counting detectors for very accurate structure factor measurements.

Temperature-induced structural change through the glass transition of silicate glass by neutron diffraction

Supercooled silicate liquids exhibit several orders of magnitude increase in viscosity at the glass-transition temperature (${T}_{\mathrm{g}}$) towards the glassy state. Such a drastic dynamical slowdown leads to an abrupt change in the slope of temperature-dependent thermodynamic properties because the measurements reflect the equilibrium-to-nonequilibrium change from liquid to glass. However, an underlying structural change associated with such a transition remains elusive. For instance, understanding the structural origin of the variation in the coefficient of thermal expansion (CTE) of silicate glasses upon vitrification is critical for glass-manufacturing processes and applications. Here, based on temperature-dependent neutron diffraction, we demonstrate that the temperature dependences of both short- and medium-range order structural parameters show a pronounced change of slope at ${T}_{\mathrm{g}}$ for a range of silicate glasses of industrial importance. Interestingly, the short- and medium-range order structural parameters are found to be mutually correlated, both below and above ${T}_{\mathrm{g}}$. Based on these results, we find that the slope change of the area of the first sharp diffraction peak at ${T}_{\mathrm{g}}$ is correlated with the extent of the CTE jump at ${T}_{\mathrm{g}}$, which offers a structural origin for the discontinuity in the CTE of glasses at ${T}_{\mathrm{g}}$. This study can therefore shine light on solving critical industrial problems, such as glass relaxation.

Investigation the effect of doping concentration in Ruthenium-doped TiO2 thin films for solar cells and sensors applications

Thin films of Ru doped TiO2 have been deposited on glass substrates at different doping concentration (0.05, 0.07, 0.09, 0.11 mol l−1) by the sol gel method. The prepared thin films were studied: their structural, morphological, optical and photocatlytic properties. The XRD spectra confirm that all the samples have anatase phase with preferential orientation along (101) plane. The position of (101) peaks shift to higher angles with increase doping concentration and 0.07 mol l−1 sample have a sharp and high intensity diffraction peak. Due to condensation and agglomeration effect. The thickness of the thin films increases from 110 nm to 255 nm with the increment of Ru concentrations. AFM images show that the films had good quality and pyramidal shape was distributed over their entire surface. Transmittance and absorbance spectra of the un-doped and Ru doped TiO2 thin films were recorded by UV–vis spectrometer. The optical band gap of the thin films increases from 3.66 eV to 3.85 eV as the Ru amount increases; this is due to the Moss-Burstein effect. Calculated results show that both the excitation coefficient (k) and refractive index (n) decreases with wavelength at all Ru concentration. Optical conductivity can improve after doping which can be a suitable material for use in sensor and solar cell applications. The photocatalytic activity was investigated by monitoring the degradation of methylene blue (MB) under visible and sun light. The results revealed that the photocatalytic activity under sun light was higher comparing to UV light for all films. Ru doped TiO2 thin films enhance the efficiency of its photocatalytic activity. It was found that the percentage of degradation was higher in 0.11 mol l−1 Ru doped TiO2 when compared with other films.

Small‐size effect on physicochemical properties of micronized fish bone during heating

The aim of the study is to investigate physicochemical properties of nano-scaled fish bone (NFB) and micro-scaled fish bone (MFB) during heating and improve their valorization by promoting their calcium release. For MFB, heating promoted its calcium release (from 0.7% to 2.2%) and solubility (from 4.6% to 11%) mainly by reducing the particle size (from 20.51 to 17.85 μm). However, the FT-IR and XRD of MFB spectra showed small change during heating. For NFB, heating hardly changed its particle size but further destroyed the crystal and chemical structure of NFB. The solubility was significantly increased from 9.8% to 14.0%. After heating at 90°C, the sharper diffraction peaks of hydroxyapatite were also observed. The calcium release was significantly promoted from 9.0% to 14%. The results showed heating could more effectively promote the calcium release of fish bones when the particle size was reduced to nanoscale. Practical applications Grass carp is the most productive freshwater fish in China. Fish bones are the main by-product from fish processing. Fish bones can be added to food as a natural calcium sources. The aims of our research are to improve the calcium release of fish bones and promote application of fish bones in food fields. After the particle size was reduced to the nanoscale using wet ball milling, heating at common cooking temperature could significantly promote the calcium to release from fish bones.

Photoluminescence and scintillation properties of Al(PO3)3–CeCl3–CsCl–CsPO3 glass scintillators

The photoluminescence (PL) and scintillation properties of Al(PO3)3–CsPO3–0.5CsCl–xCeCl3 (x = 0.05, 0.1, 0.2, 0.3, 0.5) glass scintillators were analyzed. Glasses with different concentrations of Ce3+ were fabricated via the melt-quenching method under vacuum. The X-ray diffraction patterns of all the samples except those with x = 0.3 and 0.5 presented only halo features and no sharp diffraction peaks, indicating a crystalline structure and, in turn, the amorphous nature of the glasses. The PL emission and X-ray-induced radioluminescence spectra presented a fluorescence band at ~ 350 nm, which were attributed to allowed transition from the Ce3+ 5d excited state to the 4f ground levels (2F5/2 and 2F7/2). The PL and scintillation decay time were estimated to be ~ 35 ns. The glass scintillators with x = 0.3 exhibited the maximum light yield, which was approximately 2100 photons/MeV.

Preparation conditions and medium range order modification of [formula omitted] glasses

The effect of quenching rate on the medium range order of glassy AsxSe100−x(x=20,40,50at.%) has been studied by X-ray diffraction. It was noticed that increasing quenching rate leads to a significant change in the parameters of the first sharp diffraction peak of As50Se50, comparing with samples of concentrations x≤40 at.%. The results were discussed on the light of network-connectivity transformations of As–Se system.