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Enhanced dielectric properties of BaTiO3 ceramics with cerium doping, manganese doping and Ce-Mn co-doping
摘要： Ba1?xCexTi1?yMnyO3 (where x and y varies from 0.00 to 0.03) ceramic samples are synthesized by conventional solid state reaction technique. The samples are sintered at 1473 K for 4 h. The grain size is observed to increase with increasing dopant and co-dopant concentration. The X-ray diffraction confirmed the cubic phase of these BaTiO3-based ceramics with a small amount of secondary phase. The current density shows a nearly linear relationship with voltage, and the AC resistivity of the samples is observed to decrease with increasing frequency and doping concentration. The dielectric constant and dielectric loss were observed to decrease with frequency in the lower frequency range (0.2–10 kHz), but remained almost the same at the high-frequency region (>10 kHz). Though Ce-doped samples shows better dielectric properties than Mn-doped samples, the Ce-Mn co-doped samples, having improved their dielectric properties, can be used to fabricate different optoelectric devices.
关键词： resistivity,SEM,solid state reaction,dielectric properties,XRD,grain size
更新于2025-09-09 09:28:46
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Synthesis and characterization of TiO2 co-polymeric hydrogel
摘要： In this study, TiO2 doped acrylic acid-co-vinyl pyrrolidone (AA-co-VP) composite co-polymeric hydrogel was synthesized by free radical polymerization technique. Titanium dioxide (TiO2) were chosen because of its superior properties such as high activity, chemical stability, low cost, non-toxicity, and stability during irradiation. TiO2 doping were carried out by varying mass ratios as 0.05%, 0.5% and 1%. Conversion, cross-linking and swelling values of each hydrogel were calculated. According to swelling behavior, while TiO2 dope ratio increase, swelling value was also increased. Chemical, morphological and thermal properties of hydrogels were specified by using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDX), mapping and thermogravimetric analysis (TGA-DSC) techniques. TiO2 doping provides superior properties to co-polymeric hydrogel. Hydrogels have also characteristic properties of both acrylic acid and vinyl pyrrolidone.
关键词： SEM-EDX,hydrogel,TGA-DSC,free radical polymerization,acrylic acid-co-vinyl pyrrolidone,FTIR,TiO2,swelling behavior
更新于2025-09-09 09:28:46
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Incorporation of ZnO Nanostructures in MIS Architecture through Chemical Routes
摘要： Because it’s physical properties, ZnO is considered a potential semiconductor compound for fabricating electronic and optoelectronic functional devices. In this regard, several growth techniques have been developed in order to meet the requirements of commercial devices based in this material. On the pathway for improving the performance of the current devices, low-dimensional ZnO structures seem a promising alternative. Here, we report the process to obtain a metal-insulator-semiconductor (MIS) structure based on ZnO nanostructures grown on the surface of an anodized aluminum substrate (Al2O3/Al) by chemical routes.
关键词： SEM,morphology,MIS,ZnO,XRD
更新于2025-09-09 09:28:46
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Magneto-structural properties and photocatalytic performance of sol-gel synthesized cobalt substituted Ni Cu ferrites for degradation of methylene blue under sunlight
摘要： In this study, Ni0.5-xCoxCu0.5Fe2O4 (with x varying from 0.0 to 0.5) ferrites have been synthesized by a sol-gel auto-combustion method using urea as fuel. The influence of Cobalt (Co2+) content on the structural, optical and magnetic Ni-Cu ferrites was studied by X-ray diffraction (XRD) patterns, Fourier Transform Infrared Spectroscopy (FT-IR), UV-Vis Spectroscopy (UV-DRS) and vibrating sample magnetometer (VSM). Scanning electron microscopy (SEM) and Energy dispersive X-ray (EDX) analysis have been used to determine morphology and compositions respectively. The X-ray diffraction studies have been carried out by considering the distance between adjacent crystal planes, lattice constant and average crystallite size which decrease from 44-35 nm with substitution of Co2+. FT-IR spectra show two major stretching bands around 400-600 cm-1. The magnetic parameters were measured at room temperature where increase in saturation magnetization was observed with increase in concentration of Co2+ in Ni-Cu ferrites. The photocatalytic performance study of Co2+ substituted Ni-Cu ferrites was carried out under visible and direct sunlight on methylene blue (MB) dye. The increase in degradation percentage was observed with Co2+ substitution in both visible and sunlight. The catalyst was found to be more efficient in sunlight with 91% degradation of MB within 120 minutes.
关键词： SEM,VSM,Ni-Co-Cu Ferrites,XRD,Sol-Gel Auto-Combustion,Photocatalyst
更新于2025-09-09 09:28:46
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Thermal and Morphological Studies on Bismaleimide Modified ZnO Nanoparticles
摘要： The bismaleimide (N,N'-bismaleimide-4,4'-diphenylmethane) (BMI) modified siliconized zinc oxide nanoparticles were prepared in chloroform. The FT-IR spectroscopy analysis of BMI/ZnO reveals that -NH2 groups of siliconized ZnO reacts with the maleimide double bond of bismaleimide molecules through a nucleophilic (Michael) addition reaction. The thermal (TG) and morphological properties of bismaleimide modified zinc oxide nanoparticles (BMI/ZnO), were investigated. The particle size and morphology of zinc oxide nanoparticles and siliconized zinc oxide nanoparticles were determined by XRD. The SEM images indicate that the diameter of the zinc oxide nanoparticles is in the range of 25-40 nm with a strong aggregation process. It is observed that aggregates of bismaleimide modified siliconized zinc oxide nanocomposites of different size and shape are heterogeneously distributed in the elastomeric surface due to the low shear stress and processing time, which do not make an exfoliated material.
关键词： Bismaleimide modified zinc oxide nanoparticles,FT-IR,TG,SEM,XRD
更新于2025-09-09 09:28:46
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Determination of the Elastic Behavior of Silicon Nanowires within a Scanning Electron Microscope
摘要： Three-point bending tests were performed on double-anchored, ?110? silicon nanowire samples in the vacuum chamber of a scanning electron microscope (SEM) via a micromanipulator equipped with a piezoresistive force sensor. Nanowires with widths of 35 nm and 74 nm and a height of 168 nm were fabricated. The nanowires were obtained monolithically along with their 10 ??m tall supports through a top-down fabrication approach involving a series of etching processes. The exact dimension of wire cross sections was determined by transmission electron microscopy (TEM). Conducting the experiments in an SEM chamber further raised the opportunity of the direct observation of any deviation from ideal loading conditions such as twisting, which could then be taken into consideration in simulations. Measured force-displacement behavior was observed to exhibit close resemblance to simulation results obtained by finite element modeling, when the bulk value of 169 GPa was taken as the modulus of elasticity for ?110? silicon. Hence, test results neither show any size effect nor show evidence of residual stresses for the considered nanoscale objects. The increased effect of the native oxide with reduced nanowire dimensions was captured as well. The results demonstrate the potential of the developed nanowire fabrication approach for the incorporation in functional micromechanical devices.
关键词： SEM,silicon nanowires,three-point bending tests,finite element modeling,elastic behavior
更新于2025-09-09 09:28:46
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Tuning the optical properties of ZnO:Cd by doping La and Y
摘要： Zinc oxide doped with Cadmium and rare earth elements synthesized by solgel auto combustion route is reported in this work. The studies have been carried out to analyze the structural, morphological and optical properties of Cd doped ZnO and rare earth doped ZnCdO. The XRD analysis reveals that the addition of rare earth impurity decreases the particle size of ZnCdO. La doped ZnCdO has the least particle size among the samples of ZnCdO and rare earth doped ZnCdO. The morphological changes due to the addition of rare earth impurities have been found. Samples of La doped ZnCdO shows a pillar like morphology. The hexagonal structures are prominently seen in the SEM micrographs of the samples of ZnCdO. The UV-Visible spectral analyses show that the bandgap reduces when ZnCdO is doped with the rare earth impurities. The photoluminescence spectra show the broad spectrum in visible region exhibited by ZnO and a scanty UV emission. The UV emission of rare earth doped samples decreases due to the destruction in the crystal structure. The rare earth doped ZnCdO shows a small peak in green emission that decreases when rare earth impurities are doped. There is a uniform spectral response other than a small Gaussian like green peak. The overall analyses show that the samples can be used in optoelectronic applications to work in the visible region.
关键词： rare earth elements,structural properties,optical properties,UV-Visible spectral analyses,Cadmium,SEM micrographs,photoluminescence spectra,XRD analysis,Zinc oxide,solgel auto combustion,morphological properties
更新于2025-09-09 09:28:46
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Cyclic Microwave-Assisted Metathetic Synthesis and Spectroscopic Properties of SPION/SrWO4:Er3+, Yb3+ Composites
摘要： Er3+/Yb3+ co-doped SrWO4(SrWO4:Er3+/Yb3+) composites with superparamagnetic iron oxide nanoparticles (SPIONs) were successfully synthesized by a cyclic microwave-assisted metathetic method followed by heat-treatment. The microstructure exhibited well-defined and homogeneous morphology with the SrWO4:Er3+/Yb3+ particle size of 1-2 μm and Fe3O4 particle size of 0.1-0.5 μm. The Fe3O4 particles were self-preferentially crystallized and immobilized on the surface of SrWO4:Er3+/Yb3+ particles. The synthesized SPION/SrWO4:Er3+/Yb3+ composites were characterized by X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Other spectroscopic properties were also examined using photoluminescence emission measurements and Raman spectroscopy.
关键词： Microwave-assisted metathetic synthesis,SEM,SrWO4:Er3+/Yb3+,EDX,SPIONs,Raman spectroscopy
更新于2025-09-09 09:28:46
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Carbon-titanium multilayer films: Synthesis and characterization
摘要： To synthesize Carbon-Titanium (C-Ti) multilayer thin films deposited on silicon substrates was used Thermionic Vacuum Arc (TVA) method. The coated layers consisted of a base layer of about 100 nm of Carbon deposited at low evaporation rates. Subsequently, seven Carbon and Titanium layers were deposited alternatively on top of Carbon base layer, each of them has a final thickness up to 40 nm. In this study we obtained different batches of samples by variation of the substrate temperature between 0oC and 300oC, and the ion acceleration voltage applying a negative substrate bias voltage between 0V and -700V. To characterize the microstructure properties of as prepared C-Ti multilayer structures were used Electron Microscopy techniques (TEM, SEM, STEM) and Raman Spectroscopy. Results of tribological measurements are associated with the occurrence of atomic diffusion processes at Ti/C interface. To characterize the electrical conductive properties, the electrical resistance versus temperature have been measured.
关键词： Ti/C multilayer,TVA,STEM,tribological properties,SEM,EDX,Raman,electrical properties,TEM
更新于2025-09-09 09:28:46
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Recognizing and Preventing Artifacts in Microscopy: A Roundtable Discussion
摘要： In 1991 the Technologists’ Forum presented a symposium on artifacts in biological electron microscopy [1]. Since that time the topic has not been re-visited in our symposia, special topics or roundtable discussions. Artifacts are damage caused in specimen preparation and can be confused with specimen ultrastructure. Many artifacts are a result of mechanical or chemical action during sample preparation and some artifacts are due to irradiation by the electron beam during examination of the specimen in the microscope. Recognizing specimen damage is the initial step in preventing the same problem in future preparations and not reporting erroneous data.
关键词： electron microscopy,TEM,specimen preparation,microscopy,artifacts,SEM
更新于2025-09-09 09:28:46