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Delafossite CuFeO2 (CFO) has attracted much attention as a candidate p-type photocathode for photoelectrochemical (PEC) solar hydrogen production. In this paper first, a detailed electrochemical study was carried out in order to determine the best potential range for the potentiostatic deposition of nanostructured CFO on FTO glass. The structural and morphological properties of prepared samples were characterized by XRD and FESEM. Optical and photoelectrochemical investigations show that the sample prepared at − 0.7 V exhibits the best optical properties, charge separation, and charge transfer among prepared samples. We also provided direct evidence of surface states as charge trapping centers cause carrier recombination and limit photovoltage and charge transfer at SCLJ (semiconductor/liquid junction). Deposition of plasmonic Au nanoparticles (NPs) embedded in the diamond-like carbon (DLC) scaffold on the surface of CuFeO2 not only improved optical properties but also passivated these surface states and enhanced the PEC performance, consequently.

The sputtered copper nanoparticles (Cu NPs) on amorphous hydrogenated carbon films (CuNPs@a-C:H) were deposited on a glass substrate by the codeposition method of radio-frequency (RF)-sputtering an...

The objective of this study is the experimental investigation of the silver in diamond-like carbon (Ag/DLC) nanocomposite prepared by the co-deposition of radio frequency plasma-enhanced chemical vapor deposition (RF-PECVD) and RF-sputtering. Atomic force microscopy (AFM), X-ray diffraction analyses, ultraviolet–visible (UV–visible) spectroscopy measurements were applied to describe the three-dimensional surface texture data in connection with the statistical, and multifractal analyses. Additional information about structure–property relationships in prepared Ag/DLC nanocomposite was studied in detail to allow a better understanding of the surface micromorphology. The performed analysis revealed the studied samples have multifractal properties and can be included in novel algorithms for graphical representation of complex geometrical shapes and implemented in computer simulation algorithms.

Textile industry produces huge amounts of wastewater containing synthetic dyes and impurities. Contaminants include toxic dyes, which can be found in dyeing wastewater. In textile industry, various...

Further to traditional corrosion monitoring techniques for rated deteriorations, nowadays modern electrochemical monitoring methods are promising for the control of non-rated damage mechanisms. Considering carbon steel as the most commonly used alloy in the oil and gas industry, there are special grades under NACE MR0175 standard which are immune to sour corrosion. However, according to the industry reports, their immunity can be terminated by upset conditions or on site repairs. This issue will impose either a high operational risk or exorbitant maintenance and inspection costs. Hence, in this paper, a new monitoring technology framework is discussed to lessen a catastrophic failure risk for carbon steel under wet H2S corrosion. In this regard, the application of a developed hybridized ZnO-graphene micro-electrode (ZnOG) with a mix band gap of 1.17 eV is studied. Under hydrogen sulfide attack and when ZnOG hybrids are excited by UV illumination, their photo-electrochemical responses are analyzed. ZnOG hybrids emanate informative impedance signals in a response to the formation of ZnO(1 – x)Sx nano-crystals.

The aim of the present study is to explore the 3-D micromorphology of human canine teeth materials using multifractal analysis through atomic force microscopy (AFM). The 3-D surfaces of ten extracted canine teeth of a group of 40 year old men were studied (enamel, inter enamel, inter dentin, and cementum) by AFM images in tapping mode and on square areas of 1 μm × 1 μm (512 × 512 points). The AFM images and surface multifractal analysis confirm the dependency of surface micromorphology to their structure–property of these materials across the length scales of the teeth structural architecture. Surface statistical parameters and hence, multifractal approach have been considered as reliable and sensitive tools for quantifying the 3-D surface microtexture changes of human canine teeth materials. The surface of inter dentin had the most irregular topography (the width spectrum Δα = 2.8361, value bigger than all the other Δα sample values), while the most regular topography (the width spectrum Δα = 2.6804, value lower than all the other sample values) was found in cementum. It has been concluded that multifractal analyses can be used as mathematical tools to explore the 3-D micromorphology of human canine teeth materials.

The main goal of the present work is to explore the three dimensional (3-D) atomic force microscopy (AFM) images of human teeth and investigating their micromorphology. For this purpose, 10 fresh and permanent canine teeth were selected from a group of 40-year-old men who were candidate for the experimental processes. Afterward, they were all applied for studying the morphology of their hard tissues. The tapping mode of AFM was used to characterize the surface micromorphology on the square areas of 1 μm × 1 μm (512 × 512 pts). AFM results and surface stereometric analysis indicate the relationships between the micromorphology of the surface and the structural properties of these tissues across the length scales. As can be seen, the surface of cementum has the most irregular topography (D = 2.87 ± 0.01) while the most regular topography (D = 2.43 ± 0.01) is found in dentin. Furthermore, the more and less regularity of the surface have been found in inner enamel (Sq = 26.26 nm) and dentin (Sq = 41.28 nm), respectively. Stereometric and fractal analyses give valuable information about human canine teeth via 3-D micromorphology.

Effects of diamond-like carbon (DLC) and Ag nanoparticles (Ag NPs) on photoanode of quantum dot sensitized solar cell (QDSSCs) have studied for the first time. Photoanodes include thin films of the TiO2 deposited on the FTO substrate, subsequently, graphene and CdS quantum dots (QDs) added on. Some photoanodes decorate by Ag nanoparticles and DLC thin film. Current density-voltage (J-V) characterization showed that the short-circuit current density (J sc) and power conversion efficiency (PCE) of QDSSCs with localized surface plasmon resonance (LSPR) of Ag NPs and anti-corrosion, photon and electron barrier properties of DLC thin film increase photon harvesting and improve solar cells performance. J sc of this configuration increased from about 8.87 to 14.6 mA cm-2, nearly doubled. The Ag NPs scatter photon and increase the photon harvesting in QDs. Results were showing that the presence of a thin film of DLC on TiO2/CdS/G photoanodes increased the efficiency by 97%, short circuit current by 64%, and open circuit voltage by 16%. Also, the efficiency change from 0.8 to 1.58 in the presence of both DLC and Ag NPs in cells in compare with cells without Ag NPs and DLC

The purpose of the present study is to evaluate the effects of different laser irradiations including Nd-YAG (neodymium-doped yttrium aluminum garnet laser; Nd:Y3Al5O12), Er-YAG (erbium-doped yttrium aluminum garnet laser, erbium YAG laser), and Carbon dioxide (CO2) infrared lasers on surface topography of zirconia-based ceramics samples which were prepared by copy milling technique. Three dimensional (3D) atomic force microscopy (AFM) images were applied to investigate surface properties by extracting information via MountainsMap® Premium software which divides the surface into peaks and pits and through watershed segmentation algorithm. This method made motif analysis possible by detecting surface dimensions, curvature, volume, perimeters, shape, structure, etc.

We investigate the effects of different contents of multiwall carbon nanotubes (MWCNTs) on optical and electrical properties of polyaniline (PANI). The MWCNTs/PANI composites are deposited on glass substrates coated with indium tin oxide (ITO) by the spin-coating technique. The scanning electron microscopy shows that nanotubes are coated with the PANI layer and x-ray diffraction patterns show that all deposited composite films have an amorphous character. The analysis of a UV-vis spectrophotometer indicates the blue shift of the absorbance peak and a decrease in optical band gap value by the enhancement of the CNT content in the PANI matrix while the Urbach energy increases. The Raman spectrum shows the blue shift 1404→1417 cm-1 and photoluminescence spectra show an increase in the intensity of characteristic PANI peak at 436nm with the increasing CNT content.

Nowadays, increasing awareness of environment and fossil fuels protection stimulates intensive research on clean and renewable sources of energy. Production of hydrogen from water through solar-driven splitting reactions is one of the most promising approaches in the field of photoelectrochemistry (PEC). In this work we have fabricated well-aligned, highly-ordered, smooth-mouth TiO2 nanotube arrays (TNAs) in a two-step anodization process of titanium foil, which were then used as photoelectrodes for PEC water splitting. It demonstrates for the first time correspondence between non-linear component characteristics of multiscale rough surface and crystalline structure of annealed TNAs measured at various fabrication stages and their photoelectrochemical response. The as-anodized TNAs with isotropic surface (deduced from AFM and SEM images) and largest figure of merit (according to their PEC performance) were annealed at 450 °C in air. Scale-invariant descriptors of the surface structure of the deposits involved: fractal dimension, corner frequency, roughness, size of nanostructures and their dominant habits. Moreover, X-ray diffraction data processed using the Rietveld method confirmed co-existence of various oxides, for example: TiO2 in the form of anatase, TiO and Ti3O5 phases in the TNAs under study pointing that previous well-established mechanisms of the TNA growth were to certain degree incomplete.

The effect of gamma irradiation dose in the range of 1–10kGy is investigated on the structural, optical and electrical properties of the polyaniline -emeraldine salt (PANI-ES) thin films deposited on the indium tin oxide (ITO) coated glass substrate by spin coating technique. X-ray diffraction patterns show that all deposited PANI films have an amorphous character. Fourier transform infrared spectroscopy (FTIR) confirms the emeraldine salt form of deposited PANI films. The analysis of UV–Vis spectrophotometer indicates a decrease of transmittance intensity and optical band gap with increase of gamma irradiation dose while Urbach energy increases. The photoluminescence (PL) spectra show a strong peak at 429nm due to transition from polaron band to π band in PANI structure which its intensity and peak area increase with irradiation dose increase. Electrical measurement shows that the resistivity of prepared films linearly increases with rise of gamma dose suggesting its possible application as gamma dosimeter in the studied range.

Determining surface topography of different tissues of the molar tooth with novel analytical methods has opened new horizons in dental surface measurements which characterize tooth surface quality in dentistry. Studying surface topological measurements and comparing surface morphology of hard tissue of the molar tooth are the ultimate goals of the present study. Ten molar teeth have been chosen for investigating their surface characteristics through image processing techniques. The power spectral density (PSD) and fast Fourier transform algorithms of every molar tooth containing enamel, dentin, and cementum have determined that the characterization of surface profiles is possible. As can be seen, PSD along with fractal dimensions leads to good results for teeth surface topography. Moreover, PSD angular plot assures appropriate description of surface

Among the different synthesizing method of graphene, besides having a most suitable and cost-effective method, it is essential to have high-quality graphene. For this reason, the effects of the cathode electrode, the time and type of voltage variation, dispersion time, the electrolyte salt and washing solvent on process performance of electrochemical exfoliation of graphite (EE-G) were investigated. Here, we show great promise for few-layer and few-defective graphene by optimum EE-G. The most suitable condition to produce graphene is performing the process in (NH4)2SO4. Moreover, the NaOH as salt is suitable in the synthesis of graphene quantum dots. Raman analysis clearly showed the G, D band, and 2D band of carbon for samples.

In this paper, due to the importance and abundant applications of carbon nanotubes doped with boron (CNT/B2O3) in various industries with changes in the electrical, mechanical and chemical properties, mode identification and intensity of the Raman spectra of pure and boron oxide molecule-doped spectra have been performed. The main task in this paper is to monitor the alteration of the relevant vibrational mode intensities of the pure and B-doped samples. In experimental approach, by utilizing a simple method we synthesized CNT doped with B2O3 using laser ablation in liquid environment technique. The silver nanoparticles were made by the Lee–Meisel method, and then the spontaneous and surface-enhanced Raman scattering (SERS) spectra of pure and B-doped carbon nanotubes were collected. In simulation approach, using the Gauss View and Gaussian software [basis set 6-31G, computational method DFT (B3LYP)], the spontaneous and SERS spectroscopy of pure and B-doped carbon nanotubes was calculated. Due to the presence of silver nanoparticles in the vicinity of carbon nanotube and boron element, SERS intensity to spontaneous Raman (NR) intensity ratio $$\left( {{\raise0.7ex\hbox{${I_{\text{SERS}} }$} \!\mathord{\left/ {\vphantom {{I_{\text{SERS}} } {I_{\text{NR}} }}}\right.\kern-0pt} \!\lower0.7ex\hbox{${I_{\text{NR}} }$}}} \right)$$ increases in the D, G and boron oxide modes of up to 12-fold were observed. A good agreement is found between the computational and the experimental SERS results for the vibrational spectra of the synthesized composite materials.

Nickel nanoparticles arrays, growth into hydrogenated amorphous carbon, were prepared by means of RF-plasma enhanced chemical vapor deposition and RF-sputtering co-deposition from acetylene and a nickel target. The resulting nanocomposite films were characterized by X-ray diffraction and atomic force microscopy, and their magnetic responses and magnetoresistance behavior were investigated as a function of the exciting magnetic field and the Ni nanoparticles content, which was conveniently controlled by adjusting the deposition time. These physical properties were explained by a combination of hopping and tunneling effects.

Knowing the exact pressure of the process has a great impact on the validity of the results, product quality, energy efficiency, and in some processes, on the security of work with the system. Hence, the calibration of the barometers and the accuracy of the readings should be taken seriously. Choosing the appropriate time interval for re-calibration is done according to the extent and conditions of use, uncertainty, and the inaccuracy allowed in measurement, constructive suggestion, and some other things. Failure to pay attention to the importance of periodic calibration in vacuum gauges leads to some irreparable losses in the research project and the vacuum generator system. In this study, using McLeod's barometer, the deviation of capacitive and Pirani vacuum gauges is investigated at different time intervals in the middle vacuum range, and it is determined that the vacuum gauge faces a serious deviation from the actual calibrated amount for upper and lower ranges of middle vacuum in the same working pressure range over time.

A new compound Mn0.9Co0.1Al2O4 nanowires were synthesized by thermal method. The resulting powder samples were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). We found that a set of phase transformation occurred during the process. Eventually, five phases including three spinal phases, the corundum (a-Al2O3) and MnO were formed at 1100 °C.As dominant morphology, the cubic galaxite nanowires were identified by X-ray analysis. Moreover, X-ray analysis showed that Mn3O4 and Co3O4 nanoparticles were formed in tetragonal and cubic symmetry respectively. The SEM image revealed that a dominate morphology of product has cubic nanowires shape with an average diameter in range 38–43 nm. Furthermore, we observed that influence of temperature was very important in the nanowire formation process. Electrochemical hydrogen evolution reaction (HER) of synthetic composite was evaluated and the over potential of HER was calculated about 110 mV with low Tafel slope equal to 42 mV dec−1, which was comparable with amounts reported transition metal dichalcogenides with satisfying durability.

Iron nanoparticles in amorphous hydrogenated carbon films (FeNPs@a-C:H) were prepared with RF-sputtering and RFPECVD methods by acetylene gas and Fe target. In this paper, deposition and sputtering process were carried out under influence of different initial pressure gas. The morphology and roughness of surface of samples were studied by AFM technique and also TEM images show the exact size of FeNPs and encapsulated FeNPs@a-C:H. The localized surface plasmon resonance peak (LSPR) of FeNPs was studied using UV–vis absorption spectrum. The results show that the intensity and position of LSPR peak are increased by increasing initial pressure. Also, direct energy gap of samples obtained by Tauc law is decreased with respect to increasing initial pressure.

Atomic force microscopy (AFM) images give valuable information about surface roughness of thin films based on the results of power spectral density (PSD) through the fast Fourier transform (FFT) algorithms. In the present work, AFM data are studied for silver and gold nanoparticles (Ag NPs a-C: H and Au NPs a-C: H) embedded in amorphous hydrogenated carbon films and co-deposited on glass substrate via of RF-Sputtering and RF-Plasma Enhanced Chemical Vapor Deposition methods. Here, the working gas is acetylene and the targets are Ag and Au. While time and power are constant, the only variable parameter in this study is initial pressure. In addition, the crystalline structure of Ag NPs a-C: H and Au NPs a-C: H are studied using X-ray diffraction (XRD). UV–visible spectrophotometry will also investigate optical properties and localized surface plasmon resonance (LSPR) of samples. Keywords: Ag-DLC, Au-DLC, LSPR, PSD, Crystalline structures

The aim of the present study is to verify how alternations of annealing temperatures modify optical and micromorphological properties of n-ZnO/p-NZO and n-ZnO/p-NiO multilayers. As can be seen, the optical analysis of homojunctions and hetrojunction thin films shows a red shift by increasing annealing temperature which means that annealing can shift absorption edge coefficient to the lower values of energies. Also, the effective parameters on optical properties of homo- and hetrojunction thin films such as optical band gap, Urbach energy, steepness parameter, and skin depth have been studied by their transmittance spectra. Moreover, the micromorphology of n/p ZnO homo- and heterojunctions transparent diodes have been studied by atomic force microscopy in combination with modern image processing techniques. The nano scaled stereometric analysis provides significant insights into the influence of preparation process on surface texture geometry. According to the results extracted from AFM micrographs by MountainsMap® software, it is observed that Q/ITO/ZnO/NZO sample with 300 °C annealing temperature has the normal distribution of peaks with the highest percentage of isotropy. In addition, it is observed that Q/ITO/ZnO/NiO with 500 °C annealing temperature has the most regular topography.

Characterization of carbon structure was studied through deposition of carbon films on three different substrates at various angular positions. The thin films were prepared by a low energy plasma focus device and placed on graphite, aluminum, and magnesium substrates. The deposition process performed in presence of an active, as well as a noble gas, namely nitrogen and argon. The synthesis of thin films deposited at lower angular position shows nano-crystalline graphite and amorphous carbon structures. A carbon crystal has been detected for deposition at higher angular positions. The characterization of the crystal was investigated and it was revealed that the deposited thin film has hexagonal crystal structure. Further study of crystal led to the conclusion that it can be categorized under crystalline aromatic network. The surface of all synthesized films containing crystalline aromatic network was yellowish orange color (golden). The characterization of each structure was verified by x-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM), nano-indentation, Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM) analyses. Raman spectroscopy was used as a base analysis to classify carbon structures. Raman parameters of natural graphite structure, such as G peak position and ID/IG ratio, as well as, those of carbon crystal, nano-crystalline graphite, and amorphous carbon were identified.

Findings regarding the application of gas sensing on graphene based material have led to jump in nanotechnology. Hence, producing the high-efficiency materials in this technology is a priority. Recent development in graphene based material shows that it can be a good candidate for this tar-get. With this in mind, we theoretically studied the effect of different gas molecule absorption on armchair graphene nanoribbon. In order to identify, the electronic transport of armchair graphene nanoribbons AGNR (8) by using non-equilibrium Green’s function technique, the TRANSIESTA package was used. In order to study the geometry relaxation of device, Spanish Initiative for Electronic Simulations with Thousands of Atoms (SIESTA) package was applied. Also, the generalized gradient approximation of Perdew, Burke and Ernzerhof (PBE) were chosen for the exchange correlation density function. For studying the gas sensing properties of AGNR numerical computations for CO, NO, CO2, and NH3gas molecules were adsorbed on the AGNR (8). Besides, the average local density of states (LDOS) and the transmission spectra T (E, V) for gas molecules adsorbed on the AGNR (8) were plotted. The current was measured as a function of the voltage of applied bias and the transmission spectra was investigated to see the effects of all configurations in the presence of gas molecules. Our results are encouraging and leading experimental research to develop high-quality graphene materials for well-organized applications base on gas sensing.

Novel formulations of nanocomposites derived from ZnO nanoparticles have provided potential biomedical applications as a new strategy for treatment of breast cancer. In this research, two types of ZnO nanomaterials were synthesized by sol-gel hydrothermal process and co-precipitation containing fast quenching and also surface modification methods. The cytotoxic effects on growth of the breast cancer cell lines MCF-7 were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Cell viability of the breast cancer cell line MCF-7 was reduced with increasing ZnO nanofluid concentrations at 48 and 72 h of treatment. The IC50 value of MCF-7 cells after 72 h of treatment with the first product ZnO (a) and second one ZnO

Pure and co-doped Titania thin films were prepared on aluminum substrates through the sol-gel method. The co-doped sample showed higher photocatalytic activity on benzene degradation compared to pure TiO2 under visible light illumination. XRD results showed the anatase phase for both TiO2 and co-doped TiO2 lattices with an average crystalline size of 12.9 and 10.4 nm, respectively. According to the UV-visible absorption spectra results, co-doped Titania showed higher visible light absorption compared to pure Titania. The synergistic effect of dopants caused a redshift to visible light absorption and also the lifetime of the photogenerated electron-hole were increased by induced electron levels in Titania lattice. The novelty of this study is the reactor’s specific design. We employed Al mesh as thin film substrate for 3 main reasons, first, the large surface area of the Al mesh causes to increase specific surface area of the photocatalysts, also it is a formable substrate which can be engineered geometrically to decrease the shadow spots so the thin films will receive the highest light irradiation. Also, the Al mesh flexibility facilitates the procedure of reactor design to reach a minimum pressure drop of airflow while it is installed in the air conditioners or HVAC systems.

In this paper, the results of helium plasma jet treatment of hard tissues of natural human teeth including enamel, dentin, and cementum are presented. Changes in surface morphology and structural properties have been investigated using scanning electron microscopy (SEM) in connection with multiscale image analysis, X-ray diffraction (XRD) with the aid of the Rietveld method and Williamson-Hall plots, energy dispersive X-ray (EDX) and Raman spectra analysis. Despite initial differences in scaling behaviors of the surfaces of freshly extracted tissues, spatial characteristics of their plasma-treated counterparts appeared similar taking into account the fractal measures. On the other hand, despite improvement in crystalline structure of enamel due to the plasma treatments, the structure of cementum has been found intact.

In this study, a stereometric analysis of the three-dimensional (3-D) surfaces of the Ag/diamond-like carbon (DLC) nanocomposite films was done. The nanocomposite thin films were fabricated by Radio Frequency Plasma-Enhanced Chemical Vapour Deposition (RF-PECVD). The 3-D surface microtexture was studied by high-resolution Atomic Force Microscopy (AFM) records combined with statistical analyses. More detailed information about surface statistical parameters and topographic features of analyzed samples were performed. The statistical parameters relating to the segmented motifs consistent with ISO 25178-2: 2012 have been generated using MountainsMap® Premium software. The analysis was performed by modeling Ag/DLC nanocomposite surface microtexture based on motif analysis (detection of essential characteristics in terms of surface dimensions, volume, curvature, shape) to be included in computer interactive simulation algorithms. Keywords: Ag/DLC nanocomposite, Atomic force microscopy, RF-PECVD, Stereometric analysis, Surface microtexture

Among the different synthesizing method of graphene, besides having a most suitable and cost-effective method, it is essential to have high-quality graphene. For this reason, the effects of the cathode electrode, the time and type of voltage variation, dispersion time, the electrolyte salt and washing solvent on process performance of electrochemical exfoliation of graphite (EE-G) were investigated. Here, we show great promise for few-layer and few-defective graphene by optimum EE-G. The most suitable condition to produce graphene is performing the process in (NH4)2SO4. Moreover, the NaOH as salt is suitable in the synthesis of graphene quantum dots. Raman analysis clearly showed the G, D band, and 2D band of carbon for samples.

The current rechargeable battery technologies have a failure in their performance at high pressure and temperature. In this article, we have brought theoretical insights on using boron nitride flakes as a protecting layer for a lithium-ion battery device and extended its application for a spin-dependent photon emission device. Hence, the electronic properties of pristine and lithium-doped hydrogen-edged boron nitride flakes have been studied by the first principle density functional theory calculations. In this study, we have discussed the stability, adsorption energies, bond lengths, electronic gaps, frontier molecular orbitals, the density of states, charge distributions, and dipole moments of pristine and lithium hydrogen-edged doped boron nitride flakes.

A novel insight into the effect of Pt decoration on electrochemical and photoelectrochemical behavior of TiO2 nanotube arrays (TNA) was developed in this study. TNA samples were prepared via a two-step anodization of a titanium foil and decorated with Pt by a facile photodeposition method. The formation of metallic Pt were confirmed by X-ray photoelectron spectroscopy (XPS). On the basis of our calculations, the localized states and surface states induced by Pt deposition into the bandgap of titania nanotubes, play a dominant role in trapping/detrapping charge carriers and electron transfer to electrolyte. In Pt/TNAs the appropriate electrical connection between Pt nanoparticles and TNA induces sufficiently shallow traps in the vicinity of conduction band edge of TNA which creates a fast lane for electrons toward semiconductor/electrolyte interface and decreases the density of deep trap levels compared to the pristine TNA. However, there is an optimum amount for deposited Pt. Higher amount of optimum Pt c...

Human tooth exhibits a structure of a mixture of inorganic hydroxyapatite nanocrystals and organic phases. The aim of this study is to investigate different tissues of human canine teeth surface along with the micro structure parameters of each tissue. X-ray diffraction (XRD) is used to study the amorphous or crystalline nature of each tissue with different mineral compositions and crystalline structures where the highest crystalline quality is related to enamel. The surfaces are also examined by energy-dispersive X-ray spectrometry. Moreover, crystalline quality factor is carried out to estimate the crystallinity of the tissues. Also, based on the basic Scherrer equation, the Williamson–Hall equation is applied to extend the formula for the XRD. Enamel and cementum tissues of a typical human tooth, which look similar, are composed of a large variety of wide lines with different widths through Raman spectra analysis. In addition, the applied scanning electron microscopy extracts similar morphology for all tissues with round granular structures which are denser in the cementum. Atomic force microscopy is finally used for investigation of micro-morphologies of the different tissues and the results are compared with the fractal analysis which ends to the bifractal and anisotropic nature of enamel and cementum along with monofractal and isotropic nature of dentin.

The objective of this study was to evaluate the effect of two photoactivation modes of dental LED light-curing unit (LCUs) (conventional and "Soft Start" mode) on surface texture parameters of two dental resin-based nanocomposites. LED LCUs were considered as standard light-curing devices in contemporary dental practice. Atomic force microscopy (AFM) was applied to investigate surface morphology on 90 × 90 μm2 scanning area through 2D multifractal detrended fluctuation analysis with computational algorithms basis. In order to compare 3D surface roughness at nanometer scale, singularity spectrum f[α] was used which characterize local scale properties of multifractal nature of samples. The results confirmed that larger spectrum width Δα (Δα = αmax - αmin ) of f(α) is associated with non-uniform surface morphology. Moreover, materials whose polymerization was photoactivated by the "soft start" polymerization mode, showed better quality of the surface microstructure with lower values of AFM surface texture parameters.

It is a challenge to fabricate high-quality graphene sheets due to the different effects of external factors on the fabrication process. Ultrasonic waves and temperature can be used as two important external factors to fabricate graphene. We conducted a research to study the effects of ultrasonic waves and temperature on the graphene fabrication process. To show the effects of the external factors on graphene sheets, we fabricated three samples. The first sample has been fabricated using electrochemical exfoliation method without applying any external factors. To fabricate two other samples, we used the same fabrication method but applying ultrasonic waves and temperature to homogenize the electrolyte. Second sample has been fabricated using 420 W ultrasonic waves. To fabricate third sample, 100 °C temperature has been applied to the electrolyte using heater stirrer. We studied the three fabricated samples using Fourier transform infrared spectroscopy, ultraviolet–visible, X-Ray diffraction, Energy-dispersive X-ray spectroscopy and Scanning electron microscope and Transmission electron microscopy. As a result of this research, we found that applying ultrasonic waves to homogenize the electrolyte during the fabrication process plays an important role to decrease oxygen groups and increase IG to ID rate in graphene structure.

Lead sulfide quantum dots (PbS QDs) were decorated onto a graphene surface in a semi-core–shell structure using supercritical ethanol. The temperature of ethanol played significant role in controlling size and agglomeration of QDs as well as the extent of reduction of graphene. Average size of the QDs was estimated by transmission electron microscopy to be around 3.96 nm and by quantum models to be about 4.34 nm. PbS QDs prepared at 330 °C were of high purity, and the yield was 99%. Instrumental and chemical analyses demonstrated formation of a strong bond between PbS QDs and graphene, through a Pb–O–C bridge. UV and photoluminescence measurements along with theoretical considerations revealed that integration of PbS QDs with graphene results in efficient separation of the electron–hole, thus enhancing photo → electric energy conversion. This outcome was further evidenced by comparison of performance of PbS/G in a solar cell, with the performance of pristine PbS QDs.

This communication demonstrates iron substitution in galaxite and the synthesis of a novel composite, Mn 0.83 Fe 0.21 Al 1.96 O 4 , by a simple thermal method. Hence, metal powders were heated at 1100 °C temperature for 72 h. When cooled down gradually to room temperature, the sample delaminated. Interestingly, on the sample surface, microwires were formed as timber shape with a rectangular cross-section (length>150 μm and diameter of 5–20 μm). Moreover, nanowires (77–97 nm) were observed and the surface of the sample was greenish. However, nanowires (38–53 nm) were observed on the substrate. The crystallinity and average size of the structure were formed increased by substitutions of iron ions. We discovered that the influence of temperature is very important in the wire formation process.

Antibacterial activities of various spherical zinc oxide nanoparticles and nano special morphological structures including quantum dots, nanorod arrays, nanoporous shapes and needle-like crystals had been investigated as new nanomedicine compounds. Also antibacterial activity based on minimal inhibitory concentration and the growth inhibitory zone (well method) was evaluated. ZnO nanostructures were fabricated by novel hydrolysis sol-gel-hydrothermal process followed with rapid quenching as new technique using glycerine, vegetable fatty esters such as coconut, sunflower and Lauric alcohol ethoxylated as organic templates soluble in eco-friendly nanofluids. The results showed that Bacillus anthracis and Pseudomonas aerogenes were extremely sensitive to treatment with unique ZnO nanostructured. Their growth inhibitory zone presented 30 mm and 25 mm inhibition zone with better inhibitory effect compared to the Gentamicin antibiotic standard. ZnO nanostructures had also been indicated to have a wide range of antibacterial activities against both Gram-positive and Gram-negative bacteria especially more effective on (gr+) species using the growth inhibitory zone. We could design and make significant formulations of fatty acids and esters-capped ZnO quantum dots nanofluids which created high promising agents for controlling Anthrax, Staphylococcus epidermidis and their influences in antimicrobial properties with low cost for future.

Graphene clusters consisting of 24 to 150 carbon atoms and hydrogen termination at the zigzag boundary edges have been studied, as well as clusters disordered by vacancy(s). Density Function Theory and Gaussian03 software were used to calculate graphene relative stability, desorption energy, band gap, density of states, surface shape, dipole momentum and electrical polarization of all clusters by applying the hybrid exchange-correlation functional Beke-Lee-Yang-Parr. Furthermore, infrared frequencies were calculated for two of them. Different basis sets, 6-31g**, 6-31g* and 6-31g, depending on the sizes of clusters are considered to compromise the effect of this selection on the calculated results. We found that relative stability and the gap decreases according to the size increase of the graphene cluster. Mulliken charge variation increase with the size. For about 500 carbon atoms, a zero HOMO-LUMO gap amount is predicted. Vacancy generally reduces the stability and having vacancy affects the stability differently according to the location of vacancies. Surface geometry of each cluster depends on the number of vacancies and their locations. The energy gap changes as with the location of vacancies in each cluster. The dipole momentum is dependent on the location of vacancies with respect to one another. The carbon-carbon length changes according to each covalence band distance from the boundary and vacancies. Two basis sets, 6-31g* and 6-31g**, predict equal amount for energy, gap and surface structure, but charge distribution results are completely different., Comment: 21 pages, 14 figures, 2 tables

Silver–diamond like carbon (Ag–DLC) nanocomposite films were deposited on glass and silicon substrates by co-deposition of RF-sputtering and RF-PECVD method in acetylene plasma. The effects of deposition time on creation of conductive percolation pathway in Ag–DLC nanocomposite films were investigated. The films were characterized by XRD pattern, AFM images, UV–Vis and FTIR spectra. Pressure of chamber’s variation over time was illustrated the rate of carbon and silver deposition changing. The results showed that nanoparticles’ size and surface roughness was increased by increasing deposition time. Surface plasmon resonance peak’s red shift in optical absorption spectra of samples could be depends on silver nanoparticles’ scale up. Based on electrical measurements, electrical percolation threshold was observed only in the film with 35min deposition time. Pathway was created for electric current by Ag nanoparticles’ moving in carbon matrix due to sp3 bonds and silver content in the films. The aging effect was studied for sample #2 in the threshold of percolation, where obtained Ag nanoparticles memorize its previous pathway. This investigation provides a better understanding for electric properties of Ag–DLC nanocomposite based on the percolation theory.

Carbon nanotubes (CNTs) decorated with Cu2O particles were grown on a Ni catalyst layer deposited on a Cu substrate by thermal chemical vapor deposition from liquid petroleum gas. Ni catalyst nanoparticles with different sizes were produced in an electroplating system at 45 °C using the corrosive effect of H2SO4 which was added to solution. These nanoparticles provide the nucleation sites for CNT growth avoiding the need for a buffer layer. The surface morphology of the Ni catalyst films and CNT growth over this catalyst was studied by scanning electron microscopy (SEM). High temperature surface segregation of the Cu substrate into the Ni catalyst layer and its exposition to O2 at atmospheric environment, during the CNTs growth, lead to the production of CNTs decorated with about 6 nm Cu2O nanoparticles. We used SEM to study the surface characteristics of Ni catalyst films and characteristic of grown CNTs. Raman spectroscopy, transmission electron microscopy (TEM), electron diffraction (EDX), X-ray diffraction, and X-ray photoelectron spectroscopy (XPS) revealed the formation of CNTs. The selected area electron diffraction pattern, EDX, and XPS studies show that these CNTs were decorated with Cu2O nanoparticles. This way of fabrication is the easiest and lowest cost method.

Ni-Si mixed oxide nanocomposite was prepared by co-precipitation method with Ni(NO3)2 · 6H2O and tetraethylorthosilicate (TEOS) at pH = 10.5 under reflux condition for 6 days. It was then used as a catalyst for the formation of carbon nanotubes (CNTs) by CVD procedure. Characterization of the catalyst and the CNTs was carried out using X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The results showed that Ni-Si mixed oxides nanorods with the average diameter of 3 to 4 nm play a key role in CNTs formation.

The synthesis of nanostructures are very various, and the most of scientists always fabricate them by the coprecipitation method at pH = 10.5-11. If we prepare these nanocatalysts for partial oxidation of methane (POM), processes to transforme methane gas into hydrogen or synthesis gas (H2 + CO) for obtaining exact green fuel H2 gas at different pH, what will be occurring?, and what is the influence of pH on nanoemulsion, nanofluids, nanostructures, and finally the application in syngas process? In this study we prepared many different nanoparticles containing % x (w/w) Co, Ni, Ru and La oxides over the various supports e.g. Ce-ZrO2, MgO-CeO2, AlCeO2, SiO2, SiAl2O3, SiMgO, SiO2Al-MCM-41 nano mixed oxides sized (1-2 nm) at various pH (7, 8, 9, 11) by new coprecipitation and combine with nanofluids method using different direct agent surfactant, stabilizer, binder, alcohol solvent, dispersant and variable chemical pH controllers. The prepared nanostructures were characterized by common techniques such as SEM, TEM, XRD, Raman, FTIR, BET and TPR analysis at various pH. Also many marvellous and new mixture of nanotubes-nanoclay and nanotubes-nanocomposites with high % H2 selectivity and methane conversion were fabricated by CuOx and NiOx sputtering test followed coprecipitation method at pH 9, for POM reactions used in petrochemical industry for the first time.

In this study a hot filament chemical vapour deposition (HFCVD) technique was used to prepare Fe–Cr films on Si substrate as catalysts for thermal CVD (TCVD) growing of carbon nanotubes (CNTs) from liquid petroleum gas (LPG) at 800 °C. To characterize the catalysts or CNTs, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy were used. The XPS spectra obtained at different stages of Ar+ sputtering revealed that in the depth of catalyst layers, the relative Fe–Cr concentrations are higher than the top-surface. SEM images of samples after TCVD indicate a significant CNT growing at the backside of catalyst layer compared with its top which is accompanied with morphological changes on catalyst layer such as formation of cone-shape structures, rippling, cracking and rolling of the layer. These observations were attributed to the more catalytic activity of the sub-surface beside the poor activity of the top-surface as well as the presence of individual active islands over the surface of the catalyst thin film.

TCVD growth of multiwalled carbon nanotubes (MWCNTs) was reported by catalytic decomposition of liquefied petroleum gas (LPG) at a temperature range of 580–800 °C. Laser ablation was employed as a simple and rapid technique to produce Pd nanoparticles which possess effective catalytic activities for CNT synthesis. UV–visible spectroscopy and TEM images confirmed that the Pd nanoparticles are stable for a long time and have rather spherical shape with average size of 7 nm. SEM and TEM observations and Raman spectroscopy demonstrated that the CNTs have a wavy structure, dense morphology and acceptable crystallinity. Since Pd nanoparticles are inactivated or agglomerated at extremes of the investigated temperature range, the best result of CNT synthesis was obtained at moderate temperatures. It was found that by increasing the growth temperature, crystallinity of grown CNTs is improved; however, strong agglomeration of Pd nanoparticles at high growth temperature prevents further improvement. The grown CNTs can be classified into two categories: one category includes straighter CNTs with smaller diameters and the other includes CNTs with more wavy morphology and larger diameters. The results provide a low cost, versatile and flexible growth of carbon nanotubes over Pd nanocatalysts.

Processes to transform natural gas into hydrogen or synthesis of gas (H2+CO) have been extensively studied in recent decades. H2 can be used in fuel cells as a power source and syngas may be converted into hydrocarbons via the Fischer-Tropsch synthesis. An attractive alternative process for syngas production is the partial oxidation of methane (POM). The objective of this study is to find effective conditions in using of nanofine particles for producing high activity and novel nanocatalysts to syngas, especially selectivity green fuel H2 gas as a power source. Therefore, we could produce 98.6% methane conversion, and 97.1% H2 selectivity with the help of unique stable and new nanofine materials: Eco-friendly x%Ni / SiO2, Co /Ce/ZrO2, Ru / Ce / ZrO2, and highly active Co-Ru and Ni-Ru bimetallic over Ce-ZrO2 nanosized mixed oxide support catalysts. Recently, we prepared new and interesting nanostructures by Cu and Ni sputtering on the nanosized Ce-ZrO2 solid solution support in the first time. Several surfactants, dispersants and mixture of alcohol solvents were applied in synthesis of nanostructures and nanofluids as remarkable templates.

Ni/SiO2 fine nanoparticles were prepared by coprecipitation method using various nonionic surfactants as templates with Tylose as a binder dispersant. Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD) have been used to study the templates influence on the morphology of the produced samples. Although the phase structure remained as a tetrahedron amorphous cristobalite-sin-SiO2 (101,100), rhombohedron and cubic NiO, but samples with different morphology (homogeneous nano spherical, nano rose flower and nano cubic shapes) have been achieved. These fine nanoparticles as syngas catalysts in Partial Oxidation of Methane to Hydrogen and Carbon Monoxide (POM) have been studied. Because of high Hydrogen production, it is a candidate to be a green fuel. A fixed-bed reactor at P = 1 atm, T = 800 degrees C, H2/CO = 1.8, GHSV (CH4) = 6000/hr and BET = 25, 63.5 and 87.1 m2/gr have been used as POM catalyst. From other hand these fine compounds could be converted to metallic nanotube (nanofiber) at above 850 degrees C and also bamboo shape tip mode carbon nanotube by thermal chemical vapor deposition at 800 degrees C. Transmission Electron Microscopy confirmed the metallic nanotube or single nano crystal growth. The Raman spectroscopy of all samples has been studied to confirm the different formation of Ni-Si. Choosing different templates for production of these nanoparticles could create width range of medical and industrial applications.

A hot filament chemical vapor deposition (HFCVD) method was used to prepare Fe–Cr thin film on Si substrate. The produced layers were used as catalysts for growing carbon nanotubes (CNTs) from liquid petroleum gas (LPG) at 825 °C by thermal CVD (TCVD) method. To characterize the obtained catalysts or CNTs, X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Raman spectroscopy were used. CNTs were grown on HFCVD derived Fe–Cr catalyst with the LPG as carbon source successfully. It was found that an annealing process on catalysts enhances the surface concentration of Cr atoms and reduces the sizes of catalyst particles. The grown CNTs on annealed sample were morphologically denser with smaller diameters compared to the as deposited one. In addition, the effect of filament temperature on CNTs was investigated. By increasing the filament temperature from 850 to 1050 °C the surface density and diameters of CNTs were improved.

Cu@Cu2O core-shell nanoparticles on the a-C:H thin films are prepared by co-deposition of RF-Sputtering and RF-PECVD. The samples with different Cu concentration and Cu nanoparticle with different size are grown. X-ray photoelectron spectroscopy (XPS) characterization indicates that the surface of the Cu nanoparticles oxidizes when they are exposed to air. The results are indicative that the shell of nanoparticle is mainly Cu2O phase with CuO cover thin layer. Surface plasmon resonance (SPR) peak that is signature of the existence of the Cu core nanoparticles appears in visible spectra of these films. Several interesting information are obtained from XPS study of these core-shells nanoparticles. The CuO/Cu2O ratio that is obtained by deconvolution of Cu 2p3/2 main peak and from intensity ratio of the main and satellite peak of Cu 2p3/2 are consistent. Background of XPS spectra is assigned to the scattering photoelectrons from Cu ions and plasmon of Cu nanoparticles. We observed that Cu core addition to copper oxide improves absorption of CO gas.

Nanoparticle copper/carbon composite films were prepared by co-deposition of RF-Sputtering and RF-PECVD method from acetylene gas and copper target. We investigate deposition process in the region where by changing pressure, the process converts to physical sputtering mode in constant power regime and at a critical pressure between 1.5 to 3 Pa. The estimated value of mean ion energy at this critical point of pressure is close to threshold energy of physical sputtering of copper atoms by acetylene ions. By utilizing this property and by setting initial pressure from 1.3 to 6.6 Pa, nanoparticles copper/carbon composite films were grown with different copper content. The Copper content of our films was obtained by Rutherford Back Scattering (RBS) and it varied from 2% to 97%. The copper content of the surface was obtained by X-ray Photoelectron Spectroscopy (XPS). The results of XPS at different stages of the growth and copper oxidization confirm our suggested mechanism of deposition. Atomic force microscopy (AFM) image and X-ray diffraction (XRD) indicated that copper nanoparticles were formed in our films.

We studied the reduction of active surface states at the InSb/insulator interface by the reduction of hysteresis in C – V plots and by the performance of InSb diodes operated in photovoltaic mode. The InSb wafers were cleaned with CP4A etchant (HNO 3 :CH 3 COOH:HF:H 2 O at 2:1:1:10). Then layers of 0.4 μm SiO 2 , 0.4 μm Si 3 N 4 and 0.5 μm Si 3 N 4 /SiO 2 were deposited on the cleaned surfaced by plasma enhanced chemical vapor deposition (PECVD). After measuring the surface morphology by atomic force microscopy (AFM) the atomic percentage of each element in each compound (e.g. Si and O 2 in SiO 2 layer) was studied by energy-dispersive X-ray spectroscopy (EDX). By using photoemission spectroscopy (XPS), we showed that the SiO 2 , Si 3 N 4 and Si 3 N 4 /SiO 2 layers include Sb and/or SbO x and the Sb In antisite during deposition occurred and for this reason their etch rates differ from pure SiO 2 , Si 3 N 4 and Si 3 N 4 /SiO 2 layers. Then the gold metal was deposited on the samples and capacitance voltage measurement was made on the MIS samples. The results showed hysteresis free curves if the surface has been cleaned correctly. Finally by depositing the 0.4 μm SiO 2 , 0.4 μm Si 3 N 4 and 0.5 μm Si 3 N 4 /SiO 2 on diode structure of InSb, the performance of diode in this case was compared with the anodic oxidation method. The results showed the performance of device is better than for the anodic oxidation method.