Precipitation of Nanoscale Hydrous Alumina from Sodium Aluminate Solutions

2001 ◽  
Vol 704 ◽  
Author(s):  
Biman Das ◽  
Mats Graeffe ◽  
Alicia Toscano ◽  
Chris Brancewicz ◽  
Don H. Rasmussen
Keyword(s):  
Oxalic Acid ◽  
Sodium Aluminate ◽  
X Rays ◽  
Energy Dispersive Analysis ◽  
X Ray Diffraction ◽  
Sodium Carboxymethylcellulose ◽  
X Ray ◽  
Transmission Electron Microcopy ◽  
Transmission Electron ◽  
Surface Active

AbstractSodium aluminate liquor was diluted and neutralized with water and oxalic acid in the presence of surface-active polymers polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA) and sodium carboxymethylcellulose (NaCMC). Dynamic light scattering experiments showed that the final precipitate had diameters between 80 – 300 nm when precipitated in the presence of PVP, and 600 – 800 nm when precipitated in the presence of NaCMC. The initial sols prepared using oxalic acid without surfactant had diameters of 200 – 300 nm. Scanning Electron Microscopy, SEM, Energy Dispersive Analysis by X-rays, EDAX, and X-ray diffraction were used for imaging, chemical and structural analysis of the final dialyzed particles. Transmission Electron Microcopy, TEM, images of the sols trapped and dried between nitrocellulose membranes showed that the initial particles were nearly spherical and bimodal in particle size. Larger particles had diameter of about 176 nm but were not pure solid alumina. A small fraction of initial particles had diameters much smaller than 176 nm. The discrepancies between initial and final precipitates indicate a complex precipitation pathway.

scholarly journals A Novel X-Ray Radiation Sensor Based on Networked SnO2 Nanowires

2019 ◽  
Vol 9 (22) ◽  
pp. 4878 ◽  
Author(s):  
Jae-Hun Kim ◽  
Ali Mirzaei ◽  
Hyoun Woo Kim ◽  
Hong Joo Kim ◽  
Phan Quoc Vuong ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Low Cost ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Radiation Sensor ◽  
Sno2 Nanowires ◽  
Radiation Sensors

X-Ray radiation sensors that work at room temperature are in demand. In this study, a novel, low-cost real-time X-ray radiation sensor based on SnO2 nanowires (NWs) was designed and tested. Networked SnO2 NWs were produced via the vapor–liquid–solid technique. X-ray diffraction (XRD), transmission electron microscopy (TEM) and field emission scanning electron microscopy (SEM) analyses were used to explore the crystallinity and morphology of synthesized SnO2 NWs. The fabricated sensor was exposed to X-rays (80 kV, 0.0–2.00 mA) and the leakage current variations were recorded at room temperature. The SnO2 NWs sensor showed a high and relatively linear response with respect to the X-ray intensity. The X-ray sensing results show the potential of networked SnO2 NWs as novel X-ray sensors.

Impact of Sn ions on structural and electrical description of TiO2 nanoparticles

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mutaz Salih ◽  
M. Khairy ◽  
Babiker Abdulkhair ◽  
M. G. Ghoniem ◽  
Nagwa Ibrahim ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Simple Procedure ◽  
High Energy ◽  
X Rays ◽  
X Ray Diffraction ◽  
Energy Storage Devices ◽  
X Ray ◽  
Storage Devices ◽  
Transmission Electron ◽  
High Energy Storage

Abstract In this paper, Sn-doped TiO2 nanomaterials with varying concentrations were manufactured through a simple procedure. The fabricated TiO2 and Sn loaded on TiO2 nanoparticles were studied using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-rays, Fourier transform infrared spectroscopy, and resistance analyses. The benefits of dielectric constant and ac conductivity rise at high Sn loaded concentration on TiO2 nanoparticles. The enhanced electrical conductivity is seen for STO3 (3.5% Sn doped TiO2) and STO4 (5% Sn doped TiO2) specimens are apparently associated with the introduced high defect TiO2 lattice. Furthermore, the fabricated specimens’ obtained findings may be applied as possible candidates for high-energy storage devices. Moreover, proper for the manufacture of materials working at a higher frequency.

scholarly journals Oxalic Acid-Assisted Hydrothermal Synthesis and Luminescent of Hexagonal NaYF4:Ln3+ (Ln = Sm, Eu, Yb/Er) Micro/Nanoplates

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Feng Tao ◽  
Zhishun Shen ◽  
Zhijun Wang ◽  
Da Shu ◽  
Qi Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Oxalic Acid ◽  
Molar Ratio ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ph Values ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Display Systems

Hexagonal NaYF4:Ln3+ micro/nanoplates were successfully synthesized via a hydrothermal method using oxalic acid as a shape modifier. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) have been used to study the morphologies and crystal structure of the products. The effects of the pH values and the molar ratio of oxalic acid to NaOH on the crystal growth have been investigated in detail. The time-dependent experiments have been conducted to investigate the morphology evolution process, and based on the results, a possible growth mechanism was proposed. The photoluminescence properties of 5 mol% Eu3+ and 3 mol% Sm3+ doped NaYF4 and 20 mol% Yb3+/2 mol% Er3+ codoped NaYF4 micro/nanoplates were investigated. The experimental results showed that NaYF4:Ln3+ micro/nanoplates have excellent luminescence and can be potential application in the field of light display systems, lasers, and optoelectronic devices.

Structural Properties of PbS Nanoparticles Prepared by Photo Chemical Synthesis

2013 ◽  
Vol 678 ◽  
pp. 136-139
Author(s):  
S. Kanimozhi ◽  
Dhandapani Vishnushankar ◽  
V. Veeravazhuthi
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Energy Dispersive Analysis ◽  
X Ray Diffraction ◽  
Pbs Nanoparticles ◽  
X Ray ◽  
Transmission Electron ◽  
Standard Values ◽  
Crystalline Nature ◽  
Xrd Studies

Lead sulfide (PbS) nanoparticles have been synthesized by photo chemical method and also in the dark ambient at room temperature. The pH of the solution is maintained by adding NaOH. The as-prepared PbS nanoparticles have been characterized by X-Ray Diffraction (XRD), Scanning electron microscopy (SEM), Energy-dispersive Analysis of X-ray (EDAX) and Transmission Electron Microscopy (TEM). XRD studies reveal the crystalline nature of the particles. Grain size values are calculated using Scherrer’s formula and compared with the standard values. SEM picture shows a flower like structure in the sample synthesized at dark ambient, whereas the samples synthesized in light reveals the presence of varied nanostructures like nanorods, nanowires and nanoparticles. Size of the photo chemically synthesized PbS particles observed from TEM lies between 30nm to 60nm. From EDAX we conclude that the composition is nearly stoichiometric.

Stable Pt/Ge/Au Ohmic Contact to N-GaAs with a Ta-Si-N Barrier

1993 ◽  
Vol 300 ◽  
Author(s):  
J. S. Chen ◽  
E. Kolawa ◽  
R. P. Ruiz ◽  
M-A. Nicolet
Keyword(s):  
Barrier Layer ◽  
Main Reaction ◽  
X Rays ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
Semiconductor Interface ◽  
Rich Phase ◽  
X Ray ◽  
Thermal Reactions ◽  
Transmission Electron

ABSTRACTA Pt/Ge/Au contact of the structure: <n-GaAs>/Pt(17nm)/Ge(25nm)/Au(43nm), overlaid with a Ta-Si-N barrier layer and a Au metallization layer has a contact resistivity, ρc, of 3.7×10−6 Ωcm2 after annealing at 450°C for 15 min. After aging at 450°C for 60 h, ρc slightly degrades to 5.5×10−6 Ωcm2 while the surface keeps smooth. When alloyed at 550°C for 15 min, ρc is 1.8×10−6 Ωcm2 and stays about the same value after annealing at 550°C for 1 h. Without the Ta-Si-N barrier and the Au overlayer, the Pt/Ge/Au contact alone is also ohmic after annealing at 450°C for 15 min but with a ρc of ∼10−5 Ωcm2 while the surface morphology deteriorates significantly after aging at 450°C for 20 h.The thermal reactions of this Pt/Ge/Au contact on GaAs, with or without a Ta-Si-N barrier layer, are investigated by backscattering spectrometry, x-ray diffraction, and transmission electron microscopy in conjunction with energy dispersive analyses of x-rays. For all samples, the main reaction products after annealing at 450°C for 15 min are Au7Ga2, and PtGe:As, a PtGe phase that also contains arsenic. The product phases are randomly distributed within a laterally uniform reacted layer when the Pt/Ge/Au contact is covered by a Ta-Si-N layer. Without the Ta-Si-N barrier layer, a small arsenic loss and a Ga-rich phase (probably Gaoxides) on the contact surface are observed after annealing at 450°C. In this case, the surface and contact-semiconductor interface are more faceted than with a Ta-Si-N barrier layer.

Synthesis of CdMoO4 Microcrystals by a Molten Salt Method

2012 ◽  
Vol 472-475 ◽  
pp. 2452-2457 ◽  
Author(s):  
Xiao Hui Jiang ◽  
Jun Feng Ma ◽  
Jie Cheng ◽  
Jing Rui Fang ◽  
Yong Sun
Keyword(s):  
Molten Salt ◽  
Molten Salt Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron Microcopy ◽  
Transmission Electron ◽  
Structure Morphology ◽  
Scanning Electron Microcopy ◽  
Pure Phase ◽  
Scanning Electron

Cadmium molybdate (CdMoO4) nanoparticles, cube-like crystallites and octahedral microparticles have been successfully synthesized by a molten salt method at 270°C. The structure, morphology and luminescent property of the resultant powders were characterized by X-ray diffraction (XRD), transmission electron microcopy (TEM), scanning electron microcopy (SEM), and photoluminescence (PL), respectively. The resultant samples are a pure phase of CdMoO4 and without any impurities. PL spectra results show that the optical properties of CdMoO4 particles are strongly relied on their morphologies.

Surface active holmia/ γ-alumina nanocatalyst: Preparation and characterization

2021 ◽  
Vol 19 (4) ◽  
pp. 283-294
Author(s):  
Basma A.A. Balboul ◽  
A.K. Nohman ◽  
Randa F. Abd El-baki ◽  
Moutera S. Elshemery
Keyword(s):  
Electron Microscopy ◽  
Isopropyl Alcohol ◽  
Diffuse Reflectance Spectroscopy ◽  
Physicochemical Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Surface Active ◽  
Optical Applications ◽  
Adsorption Desorption

Holmia supported γ-alumina nanocatalyst was prepared by impregnation of γ-alumina with aqueous solution of holmium acetate hydrate Ho(CH3COO)3.3.5 H2O. The physicochemical characteristics of the nanocatalyst calcined at 600°C were established by different techniques, using surface adsorption–desorption of N2 (SBET), thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and UV–vis diffuse reflectance spectroscopy (DRS). The recorded optical reflectance of the sample showed that the new self-assembled nanocatalyst is excellent as host material for advanced optical applications. Moreover, the catalyst showed enhanced catalytic activity toward Isopropyl alcohol decomposition.

IN SITU ASSEMBLY OF ZnS NANOFIBERS WITH HIGHLY ORDERED LAMELLAR MESOSTRUCTURE

2006 ◽  
Vol 05 (02n03) ◽  
pp. 245-251 ◽  
Author(s):  
JUNPING LI ◽  
YAO XU ◽  
DONG WU ◽  
YUHAN SUN
Keyword(s):  
Electron Microscope ◽  
Thermal Analyses ◽  
Blue Shift ◽  
X Rays ◽  
Energy Dispersive Analysis ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Uv Visible

ZnS nanofibers with lamellar mesostructure could be built up from in situ generated ZnS precursors via hydrothermal routes using neutral n-alkylamines as structure-directing template and ethylene diamine tetraacetic acid (EDTA) as stabilizer. The morphology and structure of the obtained products were thoroughly investigated via scanning electron microscope (SEM), energy dispersive analysis of X-rays (EDX), transmission electron microscope (TEM), X-ray powder diffraction (XRD) and thermal analyses. HRTEM and XRD results revealed that the so-produced nanofibers were lamellar mesostructure and its framework was built of crystalline wurtzite ZnS . It was also found that the distance between the layers was proportional to the chain length of the alkylamine. The UV-visible absorption spectrum showed that the nanofibers exhibited strong quantum-confined effect with a blue shift in the band gap. Finally, a probable mechanism for the assembly of the nanofibers was also proposed.

The Preparation of Fe3O4 Magnetic Nanometer Particle by Co-Precipitation Method

2012 ◽  
Vol 271-272 ◽  
pp. 320-323
Author(s):  
Xiao Chun Ma ◽  
Lei Hao Cui ◽  
Guang Fei Xu
Keyword(s):  
Electron Microscopy ◽  
Surface Active Agent ◽  
Active Agent ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Surface Active ◽  
Co Precipitation ◽  
Nanometer Particle

In this paper, the Fe3O4 magnetic nanometer particle was prepared by co-precipitation method. At the same time, the samples were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the surface active agent (PEG4000) can be good for the dispersion performance of Fe3O4 magnetic nanometer particle; and the temperature of 80°C is the appropriate drying temperature to prepare the Fe3O4 magnetic nanometer particle.

Miniature X-Ray Equipment for Diffraction and Fluorescence Analysis

1972 ◽  
Vol 16 ◽  
pp. 260-272 ◽  
Author(s):  
H. K. Herglotz
Keyword(s):  
Fluorescence Analysis ◽  
Electron Bombardment ◽  
Materials Testing ◽  
X Rays ◽  
Energy Dispersive Analysis ◽  
X Ray Diffraction ◽  
Conical Cavity ◽  
Small Power ◽  
X Ray ◽  
And Performance

AbstractEnergy yields in the generafion of monochromatic X-rays by electron bombardment are poor and the utilization of X-rays is even more wasteful, particularly in X-ray diffraction. Only a small stereoangle of radiation issuing from a flat target passes through the collimator of a camera.An end-window X-ray tube using a conical cavity as a target is more economical, since there is a finite probability of several excitation acts by one electron in the cavity. A major part of the radiation emerges from the tube in a stereoangle of ≈ 0.02 instead of 2π steradian. This and the proximity of the tube focus to the sample are favorable for X-ray diffraction, as will be demonstrated in several examples. The geometry and performance of the tube are also expected to provide a superior replacement for the weak isotopic sources normally used in energy dispersive analysis.Several versions of the tube, covered by U.S. Patent 3,584,219, H. K. Herglotz and C. D. Reilly, are described. Of particular interesf for X-ray diffraction is a double cavity tube with 2 exit ports. The Iow power consumption of the tubes (35 kV, 1 mA or less) requires only a small power supply. All equipmenf for XRD work including batteries can be accommodated in a suitcase and therefore lends itself to field use by mineralogists, for example, or in materials testing.

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