scholarly journals An Analysis of the Effect of System Variables on the Quality of Thin Films and Powders Produced by Laser-Breakdown Chemical Vapor Deposition

1987 ◽  
Vol 101 ◽  
Author(s):  
E.L. Joyce ◽  
T.R. Jervis
Keyword(s):  
Particle Size ◽  
Gas Phase ◽  
Dielectric Breakdown ◽  
Phase Particle ◽  
Metastable Phase ◽  
Rapid Quenching ◽  
Large Area ◽  
Laser Breakdown ◽  
System Pressure ◽  
System Variables

ABSTRACTA gas phase process for large area depositions on an ambient temperature substrate using laser-induced dielectric breakdown of gas phase precursors has recently been developed.1 Deposits of nickel alloys show excellent grain refinement (<10 nm) and metastable phase incorporation due to rapid quenching from the gas phase. Particle size distribution and compositional variance within the deposited films have been studied using electron microscopy and electron diffraction. Kinetic expressions to explain homogeneous gas phase nucleation and growth of the deposited materials have been developed in an effort to better understand this process. The effect of system variables on film and powder grain sizes has been studied. This analysis gives insight into the fluid flow/heat transfer patterns involved in the system and their effect on the final deposited material. The effect of system pressure, gas phase composition, and laser pulse energy, on particle size, surface area coverage, and deposition thickness are discussed.

Gas-phase particle size distributions and lead loss during spray pyrolysis of (Bi,Pb)–Sr–Ca–Cu–O

1995 ◽  
Vol 10 (7) ◽  
pp. 1644-1652 ◽  
Author(s):  
Abhijit S. Gurav ◽  
Toivo T. Kodas ◽  
Jorma Joutsensaari ◽  
Esko I. Kauppincn ◽  
Riitta Zilliacus
Keyword(s):  
Particle Size ◽  
Spray Pyrolysis ◽  
Gas Phase ◽  
Phase Particle ◽  
Average Particle Size ◽  
Particle Diameter ◽  
Processing Temperature ◽  
Average Particle ◽  
Size Distributions ◽  
Particle Size Distributions

Gas-phase particle size distributions and lead loss were measured during formation of (Bi,Pb)-Sr-Ca-Cu-O and pure PbO particles by spray pyrolysis at different temperatures. A differential mobility analyzer (DMA) in conjunction with a condensation particle counter (CPC) was used to monitor the gas-phase particle size distributions, and a Berner-type low-pressure impactor was used to obtain mass size distributions and size-classified samples for chemical analysis. For (Bi,Pb)-Sr-Ca-Cu-O, as the processing temperature was raised from 200 to 700 °C, the number average particle size decreased due to metal nitrate decomposition, intraparticle reactions forming mixed-metal oxides and particle densification. The geometric number mean particle diameter was 0.12 μm at 200 °C and reduced to 0.08 and 0.07 μm, respectively, at 700 and 900 °C. When the reactor temperature was raised from 700 and 800 °C to 900 °C, a large number (∼107 no./cm3) of new ultrafine particles were formed from PbO vapor released from the particles and the reactor walls. Particles made at temperatures up to 700 °C maintained their initial stoichiometry over the whole range of particle sizes monitorcd; however, those made at 800 °C and above were heavily depleted in lead in the size range 0.5–5.0 μm. The evaporative losses of lead oxide from (Bi,Pb)-Sr-Ca-Cu-O particles were compared with the losses from PbO particles to gain insight into the pathways involved in lead loss and the role of intraparticle processes in controlling it.

44 O 03 Gas-phase particle size distributions of (Bi,Pb)-Sr-Ca-Cu-O superconducting powders made via spray pyrolysis

1993 ◽  
Vol 24 ◽  
pp. S571-S572
Author(s):  
J. Joutsensaari ◽  
E.I. Kauppinen ◽  
J.K. Jokiniemi ◽  
A.S. Gurav ◽  
T.T. Kodas
Keyword(s):  
Particle Size ◽  
Spray Pyrolysis ◽  
Gas Phase ◽  
Phase Particle ◽  
Size Distributions ◽  
Particle Size Distributions

Gas-phase particle size distributions during vapor condensation of fullerenes

1994 ◽  
Vol 4 (5) ◽  
pp. 491-496 ◽  
Author(s):  
A.S. Gurav ◽  
T.T. Kodas ◽  
L.M. Wang ◽  
E.I. Kauppinen ◽  
J. Joutsensaari
Keyword(s):  
Particle Size ◽  
Gas Phase ◽  
Phase Particle ◽  
Vapor Condensation ◽  
Size Distributions ◽  
Particle Size Distributions

scholarly journals Fabrication and Particle Size Control of Oxide Nanoparticles by Gas Phase Reaction Assisted with DC Plasma

2007 ◽  
Vol 44 (6) ◽  
pp. 447-452 ◽  
Author(s):  
Akira Watanabe ◽  
Motoharu Fujii ◽  
Masayoshi Kawahara ◽  
Takehisa Fukui ◽  
Kiyoshi Nogi
Keyword(s):  
Particle Size ◽  
Gas Phase ◽  
Size Control ◽  
Oxide Nanoparticles ◽  
Phase Reaction ◽  
Dc Plasma ◽  
Gas Phase Reaction ◽  
Particle Size Control

scholarly journals Monte Carlo simulation for soot dynamics

2012 ◽  
Vol 16 (5) ◽  
pp. 1391-1394 ◽  
Author(s):  
Kun Zhou
Keyword(s):  
Particle Size ◽  
Monte Carlo ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Gas Phase ◽  
Volume Fraction ◽  
Soot Formation ◽  
Bimodal Distribution ◽  
Number Density ◽  
Stochastic Error

A new Monte Carlo method termed Comb-like frame Monte Carlo is developed to simulate the soot dynamics. Detailed stochastic error analysis is provided. Comb-like frame Monte Carlo is coupled with the gas phase solver Chemkin II to simulate soot formation in a 1-D premixed burner stabilized flame. The simulated soot number density, volume fraction, and particle size distribution all agree well with the measurement available in literature. The origin of the bimodal distribution of particle size distribution is revealed with quantitative proof.

scholarly journals Preparation of RGO/TiO2/Ag Aerogel and Its Photodegradation Performance in Gas Phase Formaldehyde

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Haiwang Wang ◽  
Guanqi Wang ◽  
Yukai Zhang ◽  
Yuan Ma ◽  
Zhengjie Wu ◽  
...  
Keyword(s):  
Particle Size ◽  
Gas Phase ◽  
Degradation Rate ◽  
Catalytic Efficiency ◽  
Formaldehyde Solution ◽  
Degradation Behavior ◽  
Photocatalytic Effect ◽  
Utilization Ratio ◽  
20 Nm ◽  
Degradation Effect

Abstract To increase the utilization ratio and catalytic efficiency of the nano TiO2, The RGO/TiO2/(Ag) powders and RGO/TiO2/Ag aerogel photocatalyst were designed and prepared. The composition and microstructure of RGO/TiO2/(Ag) powders and RGO/TiO2/Ag aerogel were studied, in addition, the photocatalytic activity of RGO/TiO2/(Ag) powders and RGO/TiO2/Ag aerogel was researched by the photocatalytic degradation behavior of formaldehyde solution and formaldehyde gas respectively. The result indicate that TiO2 is uniformly loaded on the surface of RGO with a particle size of 10 nm to 20 nm. When the amount of graphene oxide added is 1 wt%, RGO/TiO2 powder has the highest degradation effect on formaldehyde solution, in addition, the introduction of Ag can greatly improve the photocatalytic effect of the sample. The results also show that the pore size of RGO/TiO2/Ag aerogel is between 7.6 nm and 12.1 nm, and the degradation rate of formaldehyde gas is 77.08% within 2 hours.

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