Flame Temperature Distribution and SiO2 Particles Distribution in Oxyhydrogen Flame

2017 ◽  
Vol 726 ◽  
pp. 424-428
Author(s):  
Lei Wang ◽  
Hong Jie Wang ◽  
Hui Wang ◽  
Lan Jian Nei ◽  
Fei Xiang Lui ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Temperature Distribution ◽  
Flame Temperature ◽  
Average Diameter ◽  
Spherical Particles ◽  
Transmission Electron ◽  
Temperature Ranges ◽  
Oxyhydrogen Flame ◽  
Deposition Distance

In the production process of synthetic silica glass, SiCl4 as precursor is imported in oxyhydrogen flame, SiO2 particles generate and distribute with different states along the flame. The flame temperature and the distance above the burner are important factors to affect the particle diameters and morphologies. The 2D distribution of flame temperature was measured using sodium line-reversal method. The diameters and morphologies of SiO2 particles were analyzed by transmission electron microscopy (TEM) at 50mm, 100mm, 200mm, and 300mm above the burner. The results show that the flame temperature ranges from 2130°C to 2320°C, and the average diameter of SiO2 spherical particles increases from 50nm to 105nm as the distance increasing from 50mm to 200mm. The optimum deposition distance was discussed.

scholarly journals Methods for Calibration of Specimen Temperature During In Situ Transmission Electron Microscopy Experiments

2020 ◽  
Vol 26 (1) ◽  
pp. 3-17 ◽  
Author(s):  
Fabrizio Gaulandris ◽  
Søren B. Simonsen ◽  
Jakob B. Wagner ◽  
Kristian Mølhave ◽  
Shun Muto ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Temperature Calibration ◽  
Transmission Electron ◽  
Calibration Methods ◽  
Scanning Transmission ◽  
Stem Temperature ◽  
Temperature Ranges ◽  
Technological Improvements

AbstractOne of the biggest challenges for in situ heating transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) is the ability to measure the local temperature of the specimen accurately. Despite technological improvements in the construction of TEM/STEM heating holders, the problem of being able to measure the real sample temperature is still the subject of considerable discussion. In this study, we review the present literature on methodologies for temperature calibration. We analyze calibration methods that require the use of a thermometric material in addition to the specimen under study, as well as methods that can be performed directly on the specimen of interest without the need for a previous calibration. Finally, an overview of the most important characteristics of all the treated techniques, including temperature ranges and uncertainties, is provided in order to provide an accessory database to consult before an in situ TEM/STEM temperature calibration experiment.

Transmission Electron Microscopy study of lead sulfide whiskers

1989 ◽  
Vol 47 ◽  
pp. 444-445
Author(s):  
S.A. Mansour ◽  
R. Scholz
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Lead Sulfide ◽  
Carbon Film ◽  
Flame Temperature ◽  
High Resolution Electron Microscopy ◽  
Spiral Coil ◽  
Transmission Electron

This paper describes a transmission electron microscopy (TEM) study of the structure and growth mechanism of lead sulfide (PbS) whiskers. PbS whiskers were grown inside the stainless steel nozzle of a kerosene burner. The nozzle had a 0.5 mm aperture, and was fitted with an Al-spiral coil to filter kerosene impurities. The burner was operated continuously for four weeks at a kerosene pressure of 2-3 bars and a flame temperature of about 350°C before the nozzle clogged. A thick black deposit of fine PbS whiskers was found inside the nozzle.TEM specimens were prepared by ultrasonically suspending the fine black powder in alcohol. The suspended particles were deposited on a perforated carbon film supported on a copper grid, and examined with a JEM-1200EX transmission electron microscope operated at 120kV accelerating voltage. A JEM-4000EX transmission electron microscope was used for high resolution electron microscopy.Fig. 1. shows an EM micrograph of typical PbS whiskers. Each appears to have a high-contrast core encapsulated in a lower contrast shell. The electron diffraction pattern of a single whisker protruding over a hole in the carbon film is shown in Fig. 2.

Nanostructured CaWO4, CaWO4:Eu3+ and CaWO4:Tb3+ Particles: Sonochemical Synthesis and Luminescent Properties

2008 ◽  
Vol 8 (3) ◽  
pp. 1183-1190 ◽  
Author(s):  
Chunxia Li ◽  
Cuikun Lin ◽  
Xiaoming Liu ◽  
Jun Lin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Field Emission ◽  
Spherical Particles ◽  
X Ray Diffraction ◽  
Blue Emission Band ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Nanostructured CaWO4, CaWO4:Eu3+, and CaWO4:Tb3+ phosphor particles were synthesized via a facile sonochemical route. X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, photoluminescence, low voltage cathodoluminescence spectra, and photoluminescence lifetimes were used to characterize the as-obtained samples. The X-ray diffraction results indicate that the samples are well crystallized with the scheelite structure of CaWO4. The transmission electron microscopy and field emission scanning electron microscopy images illustrate that the powders consist of spherical particles with sizes from 120 to 160 nm, which are the aggregates of even smaller nanoparticles ranging from 10 to 20 nm. Under UV light or electron beam excitation, the CaWO4 powder exhibited a blue emission band with a maximum at 430 nm originating from the WO2−4 groups, while the CaWO4:Eu3+ powder showed red emission dominated by 613 nm ascribed to the 5D0 → 7F2 of Eu3+, and the CaWO4:Tb3+ powders showed emission at 544 nm, ascribed to the 5D4 → 7F5 transition of Tb3+. The PL excitation and emission spectra suggest that the energy is transferred from WO2−4 to Eu3+CaWO4:Eu3+ and to Tb3+ in CaWO4:Tb3+. Moreover, the energy transfer from WO2−4 to Tb3+ in CaWO4:Tb3+ is more efficient than that from WO2−4 to Eu3+ in CaWO4:Eu3+. This novel and efficient pathway could open new opportunities for further investigating the novel properties of tungstate materials.

scholarly journals The morphology of silver nanoparticles prepared by enzyme-induced reduction

2012 ◽  
Vol 3 ◽  
pp. 404-414 ◽  
Author(s):  
Henrik Schneidewind ◽  
Thomas Schüler ◽  
Katharina K Strelau ◽  
Karina Weber ◽  
Dana Cialla ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silver Nanoparticles ◽  
Chemical Composition ◽  
Cross Sections ◽  
Silver Nanoparticle ◽  
Spherical Particles ◽  
Initial Growth ◽  
Nanoparticle Films ◽  
Transmission Electron

Silver nanoparticles were synthesized by an enzyme-induced growth process on solid substrates. In order to customize the enzymatically grown nanoparticles (EGNP) for analytical applications in biomolecular research, a detailed study was carried out concerning the time evolution of the formation of the silver nanoparticles, their morphology, and their chemical composition. Therefore, silver-nanoparticle films of different densities were investigated by using scanning as well as transmission electron microscopy to examine their structure. Cross sections of silver nanoparticles, prepared for analysis by transmission electron microscopy were additionally studied by energy-dispersive X-ray spectroscopy in order to probe their chemical composition. The surface coverage of substrates with silver nanoparticles and the maximum particle height were determined by Rutherford backscattering spectroscopy. Variations in the silver-nanoparticle films depending on the conditions during synthesis were observed. After an initial growth state the silver nanoparticles exhibit the so-called desert-rose or nanoflower-like structure. This complex nanoparticle structure is in clear contrast to the auto-catalytically grown spherical particles, which maintain their overall geometrical appearance while increasing their diameter. It is shown, that the desert-rose-like silver nanoparticles consist of single-crystalline plates of pure silver. The surface-enhanced Raman spectroscopic (SERS) activity of the EGNP structures is promising due to the exceptionally rough surface structure of the silver nanoparticles. SERS measurements of the vitamin riboflavin incubated on the silver nanoparticles are shown as an exemplary application for quantitative analysis.

Characterization of Pt-Doped WO3 Nanoparticles Synthesized by Flame Spray Pyrolysis

2012 ◽  
Vol 326-328 ◽  
pp. 394-399
Author(s):  
Thanittha Samerjai ◽  
Nittaya Tamaekong ◽  
Sukon Phanichphant
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Spray Pyrolysis ◽  
Nitrogen Adsorption ◽  
Single Step ◽  
Spherical Particles ◽  
Bet Surface Area ◽  
Flame Spray Pyrolysis ◽  
Flame Spray ◽  
Transmission Electron

Undoped WO3and WO3nanoparticles doped with 0.251.0 wt.% Pt were successfully produced in a single step by flame spray pyrolysis (FSP) [. Tungsten (VI) ethoxide 5% w/v in ethanol 99.8% and platinum (II) acetylacetonate were used as W and Pt precursors respectively dissolved in ethanol. The undoped WO3and Pt-doped WO3nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). The BET surface area (SSABET) of the nanoparticles was measured by nitrogen adsorption. From BET measurement,SSABETincreased anddBETdecreased with increasing Pt concentration from 0 to 1.0 wt.%. The morphology and accurate size of the primary particles were further investigated by high-resolution transmission electron microscopy (HRTEM). The crystallite size of undoped WO3spherical was found to be ranging from 520 nm and the crystallite sizes of 0.251.0 wt.% Pt-doped WO3spherical particles were found to be in the range of 520 nm.

Effect of Laser Repetition Rate on Silver Nanoparticles Colloid

2012 ◽  
Vol 538-541 ◽  
pp. 1888-1891 ◽  
Author(s):  
Bing Xu ◽  
Ren Guo Song ◽  
Chao Wang ◽  
Wang Zhao He
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silver Nanoparticles ◽  
Repetition Rate ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Average Diameter ◽  
Distilled Water ◽  
Laser Repetition Rate ◽  
Transmission Electron

The silver nanoparticles colloid was prepared by pulsed laser ablation in distilled water under various laser repetition rates. The particles size, morphologies and absorption spectroscopy of the obtained nanoparticles colloids were characterized by ultraviolet to visible (UV-Vis) spectrometer and transmission electron microscopy (TEM). The average diameter and its distribution were analyzed by Image-ProPlus software. The results showed that the average diameter of the silver nanoparticles prepared at the laser repetition rate of 10 HZ was the smallest (D=29.75 nm), also, the distribution of particle size decreases with increasing the laser repetition rate.

scholarly journals Synthesis, characterization, and growth simulations of Cu–Pt bimetallic nanoclusters

2014 ◽  
Vol 5 ◽  
pp. 1371-1379 ◽  
Author(s):  
Subarna Khanal ◽  
Ana Spitale ◽  
Nabraj Bhattarai ◽  
Daniel Bahena ◽  
J Jesus Velazquez-Salazar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Spherical Aberration ◽  
Average Diameter ◽  
Simulation Method ◽  
Dark Field ◽  
Pt Nanoclusters ◽  
Bimetallic Nanoclusters ◽  
Transmission Electron ◽  
Scanning Transmission

Highly monodispersed Cu–Pt bimetallic nanoclusters were synthesized by a facile synthesis approach. Analysis of transmission electron microscopy (TEM) and spherical aberration (C s)-corrected scanning transmission electron microscopy (STEM) images shows that the average diameter of the Cu–Pt nanoclusters is 3.0 ± 1.0 nm. The high angle annular dark field (HAADF-STEM) images, intensity profiles, and energy dispersive X-ray spectroscopy (EDX) line scans, allowed us to study the distribution of Cu and Pt with atomistic resolution, finding that Pt is embedded randomly in the Cu lattice. A novel simulation method is applied to study the growth mechanism, which shows the formation of alloy structures in good agreement with the experimental evidence. The findings give insight into the formation mechanism of the nanosized Cu–Pt bimetallic catalysts.

Homotypic fusion between aggregated lysosomes triggered by elevated [Ca2+]i in fibroblasts

1997 ◽  
Vol 110 (18) ◽  
pp. 2227-2238 ◽  
Author(s):  
A.C. Bakker ◽  
P. Webster ◽  
W.A. Jacob ◽  
N.W. Andrews
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Average Diameter ◽  
Transmission Electron Microscopy Analysis ◽  
High Voltage Electron Microscopy ◽  
Permeabilized Cells ◽  
Voltage Electron ◽  
Transmission Electron ◽  
Streptolysin O ◽  
Electron Microscopy Analysis

Previous studies demonstrated that microinjection of antibodies to the cytoplasmic domain of the lysosomal glycoprotein lgp120 induces aggregation of lysosomes in NRK cells. Here we show that the antibody-clustered vesicles do not co-localize with MPR and ss-COP-containing organelles, confirming their lysosomal nature. Observations by transmission and high voltage electron microscopy indicated that, although tightly apposed to each other, aggregated lysosomes remained as separate vesicles, with an average diameter of 0.3-0.4 micron. However, when cells microinjected with antibody were exposed to the Ca2+ ionophore ionomycin, large vesicles were formed within the lysosome clusters, suggesting the occurrence of lysosome-lysosome fusion. Stereological measurements of lysosome diameters on confocal and transmission electron microscopy indicated that the large lgp120-positive vesicles could have originated from the fusion of 3 up to 15 individual lysosomes. To verify if agents that mobilize Ca2+ from intracellular stores had the same effect, anti-lgp120-microinjected cells were treated with thapsigargin, and with the receptor-mediated agonists bombesin and thrombin. Thapsigargin also induced the formation of large lgp120-containing vesicles, detected by both confocal and transmission electron microscopy. Analysis of antibody-clustered lysosomes in streptolysin O-permeabilized cells indicated that an intracellular free Ca2+ concentration of 1 microM was sufficient to trigger formation of large lysosomes.

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