scholarly journals Synthesis and characterization of ZnSe: Ag/SiO2 nanoparticles

2021 ◽  
Vol 261 ◽  
pp. 02063
Author(s):  
Fenghua Huang ◽  
Tao Huang ◽  
Xiangwei Wu ◽  
Wenhui Pang
Keyword(s):  
Visible Spectrum ◽  
Fluorescence Analysis ◽  
Sio2 Nanoparticles ◽  
Fluorescence Properties ◽  
Silicon Dioxide Nanoparticles ◽  
Transmission Electron ◽  
Structure Morphology ◽  
Potential Applications ◽  
The Stability

Argentum-doped zinc selenide/silicon dioxide nanoparticles (expressed as ZnSe: Ag/SiO2) were synthesized by Stöber method. The structure, morphology and fluorescence properties of the quantum dots were characterized by X-ray powder diffraction, transmission electron microscopy, infrared spectrum, ultraviolet-visible spectrum and fluorescence spectrum. The results show that the as-prepared ZnSe: Ag/SiO2 nanoparticles are spherical, most of which are about 30 nm in size, and have good fluorescence properties. Compared with that of ZnSe: Ag nanoparticles, the stability of ZnSe: Ag/SiO2 nanoparticles is enhanced obviously. The ZnSe: Ag/SiO2 nanoparticles will have potential applications in biological fluorescence analysis.

TEM characterization of Au/Polysilicon interactions

1990 ◽  
Vol 48 (4) ◽  
pp. 650-651
Author(s):  
N. David Theodore ◽  
Leslie H. Allen ◽  
C. Barry Carter ◽  
James W. Mayer
Keyword(s):  
Solid Phase ◽  
Single Crystal Silicon ◽  
Chemical Vapor ◽  
Electrical Contacts ◽  
Silicon Substrates ◽  
Crystal Silicon ◽  
Transmission Electron ◽  
Polysilicon Films ◽  
The Stability

Metal/polysilicon investigations contribute to an understanding of issues relevant to the stability of electrical contacts in semiconductor devices. These investigations also contribute to an understanding of Si lateral solid-phase epitactic growth. Metals such as Au, Al and Ag form eutectics with Si. reactions in these metal/polysilicon systems lead to the formation of large-grain silicon. Of these systems, the Al/polysilicon system has been most extensively studied. In this study, the behavior upon thermal annealing of Au/polysilicon bilayers is investigated using cross-section transmission electron microscopy (XTEM). The unique feature of this system is that silicon grain-growth occurs at particularly low temperatures ∽300°C).Gold/polysilicon bilayers were fabricated on thermally oxidized single-crystal silicon substrates. Lowpressure chemical vapor deposition (LPCVD) at 620°C was used to obtain 100 to 400 nm polysilicon films. The surface of the polysilicon was cleaned with a buffered hydrofluoric acid solution. Gold was then thermally evaporated onto the samples.

Structural Evolution Upon Annealing of Multi-Layer Si/Fe Thin Films Prepared by Magnetron Sputtering

2007 ◽  
Vol 561-565 ◽  
pp. 1161-1164
Author(s):  
Xiao Na Li ◽  
Bing Hu ◽  
Chuang Dong ◽  
Xin Jiang
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Room Temperature ◽  
Structural Evolution ◽  
Radio Frequency Magnetron Sputtering ◽  
Transmission Electron ◽  
Direct Band ◽  
The Stability ◽  
Sputtering System

Fe/Si multi-layer films were fabricated on Si (100) substrates utilizing radio frequency magnetron sputtering system. Si/β-FeSi2 structure was found in the films after the deposition. Structural characterization of Fe-silicide sample was performed by transmission electron microscopy, to explore the dependence of the microstructure of β-FeSi2 film on the preparation parameters. It was found that β-FeSi2 particles were formed after the deposition without annealing, whose size is less than 20nm ,with a direct band-gap of 0.94eV in room temperature. After annealing at 850°C, particles grow lager, however the stability of thin films was still good.

scholarly journals Assessing the Stability of Surface Lights for use in Retrievals of Nocturnal Atmospheric Parameters

2019 ◽  
Author(s):  
Jeremy E. Solbrig ◽  
Steven D. Miller ◽  
Jianglong Zhang ◽  
Lewis Grasso ◽  
Anton Kliewer
Keyword(s):  
Near Infrared ◽  
Correlation Coefficients ◽  
Visible Spectrum ◽  
Light Sources ◽  
Infrared Observations ◽  
Spatially Resolved ◽  
Relative Standard ◽  
Geometric Variables ◽  
The Stability

Abstract. Detection and characterization of aerosols is inherently limited at night due to a lack of sensitivity—information typically provided by visible spectrum observations. The VIIRS Day/Night Band (DNB) onboard the Suomi-NPP satellite is a first-of-its-kind calibrated sensor capable of collecting visible/near-infrared observations during both day and night. Multiple studies have suggested that anthropogenic light emissions such as those from cities and gas flares may be useable as light sources for retrieval of atmospheric properties including cloud and aerosol optical depth. However, their use in this capacity requires proper characterization of their intrinsic variation, which represents a source of retrieval uncertainty. In this study we use 18 months of cloud-cleared VIIRS data collected over five selected geographic domains to assess the stability of anthropogenic light emissions and their response to varied satellite and lunar geometries. Timeseries are developed for each location in each domain for DNB radiance, four infrared channels, and satellite and lunar geometric variables, and spatially-resolved correlation coefficients are computed between DNB radiance and each of the other variables. This analysis finds that while many emissive light sources are too unstable to be used reliably for atmospheric retrievals, some sources exhibit a sufficient stability (relative standard deviation

scholarly journals Synthesis, Characterization, and Pesticidal Activity of Emamectin Benzoate Nanoformulations against Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae)

Molecules ◽  
2019 ◽  
Vol 24 (15) ◽  
pp. 2801 ◽  
Author(s):  
Asem Elabasy ◽  
Ali Shoaib ◽  
Muhammad Waqas ◽  
Mingxing Jiang ◽  
Zuhua Shi
Keyword(s):  
Electron Microscopy ◽  
Plant Protection ◽  
Climatic Conditions ◽  
X Ray Diffraction ◽  
Emamectin Benzoate ◽  
Silicon Dioxide Nanoparticles ◽  
Phenacoccus Solenopsis ◽  
Commercial Formulation ◽  
Transmission Electron ◽  
Potential Applications

Using nanotechnology to develop new formulations of pesticides is considered a possible option in enhancing the efficiency, safety, and photostability of pesticides under various climatic conditions. In the present study, two novel nanoformulations (NFs) were successfully prepared based on nano-delivery systems for emamectin benzoate (EMB) by loading it on cellulose nanocrystals (CNCs) and silicon dioxide nanoparticles (SNPs) as carriers through a freeze-drying method. The synthesized nanoformulations were examined using field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and dynamic light scattering (DLS). The results showed that SNPs and CNCs had a loading efficiency of 43.31% and 15.04% (w/w) for EMB, respectively, and could effectively protect EMB from photolysis under UV radiation. The LC50 values for EMB + SNPs, EMB + CNCs, and EMB commercial formulation against Phenacoccus solenopsis were 0.01, 0.05, and 0.31 μg/mL, respectively, indicating that both NFs were more effective than the EMB commercial formulation. This work seeks to develop new nano-carriers for potential applications of pesticides in plant protection, which will reduce the recommended dose of pesticides and thereby decrease the amount of pesticide residue in food and the environment.

Synthesis and Characterization of Asparagine-Modified and Terbium-Doped Spherical Hydroxyapatite Nanoparticle

2016 ◽  
Vol 697 ◽  
pp. 62-66
Author(s):  
Xiao Feng Xing ◽  
Liang Liang Luo ◽  
Yu Ping Guo ◽  
Wei Min Gao ◽  
Liang Hu
Keyword(s):  
Uv Light ◽  
Raw Materials ◽  
Calcium Nitrate ◽  
Thermal Method ◽  
Fluorescent Properties ◽  
Transmission Electron ◽  
Light Region ◽  
Structure Morphology ◽  
Fluorescence Spectrometer

The spherical hydroxyapatite nanoparticles (HAP) were synthesized by hydro-thermal method, and calcium nitrate, terbium oxide, diammonium hydrogen phosphate were used as raw materials with the help of surfactant L-Asparagine. Meanwhile, different amount of Tb was added to investigate the effect of different terbium dropping amount on the properties of HAP. The structure, morphology and luminescent of the obtained HAP that was characterized via X-ray powder diffraction (XRD), fluorescence spectrometer (PL) and transmission electron microscope (TEM). Results showed that spherical HAP which in average of 30 nm with good dispersion showed remarkable fluorescent properties and their maximum emission were observed at 543 nm, which could be also excited at uv light region of 377 nm.The optimum mole fraction of Tb was 3%. Therefore terbium-doped spherical HAP of prepared sample would be tracked by flourescence.

Preparation and Characterization of Cu-SiO2 Nanoparticles

2007 ◽  
Vol 121-123 ◽  
pp. 255-258 ◽  
Author(s):  
Young Hwan Kim ◽  
Beong Gi Jo ◽  
Jee Hean Jeong ◽  
Young Soo Kang
Keyword(s):  
Silica Nanoparticles ◽  
Room Temperature ◽  
Sio2 Nanoparticles ◽  
Hybrid Structures ◽  
Cu Nanoparticles ◽  
Stöber Method ◽  
X Ray ◽  
Transmission Electron ◽  
Hydrolysis And Condensation

A room temperature route for doping silica particles with Cu nanoparticles to achieve hybrid structures is introduced. First, silica nanoparticles were synthesized according to the well-known Stöber method by hydrolysis and condensation of TEOS in a mixture of ethanol with water, using ammonia as catalyst to initiate the reaction. These SiO2 nanoaprticles were dried at 100 oC. We measured the size of these nanoparticles with transmission electron microscopy (TEM). Second, Cu-SiO2 nanoparticles were synthesized by reaction with CuCl2 and SiO2 nanoparticles in presence of catalyst at room temperature for 12 hrs. Results show silica nanoparticles of about 70 nm size with regularly deposited Cu nanoparticles. Cu-SiO2 nanoparticles were investigated with TEM images, energy dispersive X-ray analysis (EDX) spectrum and so on.

Synthesis and characterization of monodisperse metalloporphyrin nanospheres

2009 ◽  
Vol 24 (12) ◽  
pp. 3510-3515
Author(s):  
Chunhui Li ◽  
Wanjie Wang ◽  
Yanxia Cao
Keyword(s):  
Room Temperature ◽  
Influence Factors ◽  
Visible Spectrum ◽  
Synthesis And Characterization ◽  
Transmission Electron ◽  
High Uniformity ◽  
Reprecipitation Method ◽  
Temperature Scanning ◽  
Surfactant Assisted

Uniform monodisperse nanospheres of tetra-kis(4-methoxylphenyl) porphynatemanganese (III) chloride [MnIII(TMOPP)Cl] of about 200 nm have been synthesized through a facile surfactant-assisted reprecipitation method at room temperature. Scanning electron microscopy, transmission electron microscope, infrared spectrum, ultraviolet–visible spectrum, and elemental analysis were adopted to characterize the as-prepared metalloporphyrin nanostructures. The influence factors in the reaction to the sizes and morphologies of porphyrin nanoparticles were discussed. The sizes of porphyrin nanoparticles were affected mainly by the porphyrin concentration and only monodisperse nanoshperes with high uniformity in sizes and shapes can self-assemble to form order two-dimensional superstructures.

scholarly journals Microstructure Characterization of Welds in X5CrNiCuNb16-4 Steel in Overaged Condition

2019 ◽  
Vol 19 (1) ◽  
pp. 57-69
Author(s):  
A. Ziewiec ◽  
A. Zielińska-Lipiec ◽  
J. Kowalska ◽  
K. Ziewiec
Keyword(s):  
Electron Microscopy ◽  
Aging Time ◽  
Energy Dispersive Spectrometry ◽  
Solution Treatment ◽  
X Ray Diffraction ◽  
Density Distributions ◽  
Transmission Electron ◽  
Steel Welds ◽  
The Stability

AbstractThe paper presents the results of the investigation of microstructure of the welded X5CrNiCuNb16-4 (17-4PH) steel after solution treatment and aging at 620°C for different periods. The microstructure and the phase composition of the steel was investigated using light microscopy (LM), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), transmission electron microscopy (TEM) and the X-ray diffraction (XRD). Hardness was measured for samples aged at different times. Density distributions of Cu precipitates were established. The investigation has shown that the microstructure of the X5CrNiCuNb16-4 steel welds after aging at 620 ° C consists of tempered martensite, fine Cu precipitates and austenite. It was observed that the size of the Cu precipitates increases with increasing the aging time, what affects the decrease of hardness. Simultaneously, the quantity of reversed austenite increases with increase of aging time. It was revealed that enrichment of the austenite in Ni, Cu and C affects the increase of Ms, but this factor does not determine the stability of austenite.

scholarly journals Synthesis and Characterization of Hybrid Core-Shell Fe3O4/SiO2 Nanoparticles for Biomedical Applications

Acta Naturae ◽  
2017 ◽  
Vol 9 (4) ◽  
pp. 58-65
Author(s):  
I. V. Zelepukin ◽  
V. O. Shipunova ◽  
A. B. Mirkasymov ◽  
P. I. Nikitin ◽  
M. P. Nikitin ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
High Sensitivity ◽  
Sio2 Nanoparticles ◽  
Quantitative Information ◽  
Eukaryotic Cell ◽  
Polymer Shell ◽  
Transmission Electron ◽  
Shell Forming ◽  
Electron Microdiffraction

The creation of markers that provide both visual and quantitative information is of considerable importance for the mapping of tissue macrophages and other cells. We synthesized magnetic and magneto-fluorescent nanomarkers for the labeling of cells which can be detected with high sensitivity by the magnetic particle quantification (MPQ) technique. For stabilization under physiological conditions, the markers were coated with a dense silica shell. In this case, the size and zeta-potential of nanoparticles were controlled by a modified Stober reaction. Also, we developed a novel facile two-step synthesis of carboxylic acid-functionalized magnetic SiO2 nanoparticles, with a carboxyl polymer shell forming on the nanoparticles before the initiation of the Stober reaction. We extensively characterized the nanomarkers by transmission electron microscopy, electron microdiffraction, and dynamic and electrophoretic light scattering. We also studied the nanoparticle cellular uptake by various eukaryotic cell lines.

scholarly journals Application of Remote Sensing to the Investigation of Rock Slopes: Experience Gained and Lessons Learned

2019 ◽  
Vol 8 (7) ◽  
pp. 296 ◽  
Author(s):  
Doug Stead ◽  
Davide Donati ◽  
Andrea Wolter ◽  
Matthieu Sturzenegger
Keyword(s):  
Remote Sensing ◽  
Lessons Learned ◽  
Rock Slopes ◽  
Field Methods ◽  
Potential Applications ◽  
Remote Sensing Techniques ◽  
The Stability ◽  
Difficult Terrain ◽  
Remote Sensing Methods

The stability and deformation behavior of high rock slopes depends on many factors, including geological structures, lithology, geomorphic processes, stress distribution, and groundwater regime. A comprehensive mapping program is, therefore, required to investigate and assess the stability of high rock slopes. However, slope steepness, rockfalls and ongoing instability, difficult terrain, and other safety concerns may prevent the collection of data by means of traditional field techniques. Therefore, remote sensing methods are often critical to perform an effective investigation. In this paper, we describe the application of field and remote sensing approaches for the characterization of rock slopes at various scale and distances. Based on over 15 years of the experience gained by the Engineering Geology and Resource Geotechnics Research Group at Simon Fraser University (Vancouver, Canada), we provide a summary of the potential applications, advantages, and limitations of varied remote sensing techniques for comprehensive characterization of rock slopes. We illustrate how remote sensing methods have been critical in performing rock slope investigations. However, we observe that traditional field methods still remain indispensable to collect important intact rock and discontinuity condition data.

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