Synthesis of nanocrystalline MgH2 powder by gas-phase condensation and in situ hydridation: TEM, XPS and XRD study

2007 ◽  
Vol 434-435 ◽  
pp. 721-724 ◽  
Author(s):  
O. Friedrichs ◽  
L. Kolodziejczyk ◽  
J.C. Sánchez-López ◽  
C. López-Cartés ◽  
A. Fernández
Keyword(s):  
Gas Phase ◽  
Xrd Study

scholarly journals In Situ Observation of Electron-Beam-Induced Formation of Nano-Structures in PbTe

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 163
Author(s):  
Iryna Zelenina ◽  
Igor Veremchuk ◽  
Yuri Grin ◽  
Paul Simon
Keyword(s):  
Electron Beam ◽  
Gas Phase ◽  
Threshold Current ◽  
Threshold Current Density ◽  
Atomic Scale ◽  
In Situ Observation ◽  
Nano Structures ◽  
Transmission Electron ◽  
Initial Crystal

Nano-scaled thermoelectric materials attract significant interest due to their improved physical properties as compared to bulk materials. Well-shaped nanoparticles such as nano-bars and nano-cubes were observed in the known thermoelectric material PbTe. Their extended two-dimensional nano-layer arrangements form directly in situ through electron-beam treatment in the transmission electron microscope. The experiments show the atomistic depletion mechanism of the initial crystal and the recrystallization of PbTe nanoparticles out of the microparticles due to the local atomic-scale transport via the gas phase beyond a threshold current density of the beam.

scholarly journals An Atmospheric Origin for HCN-Derived Polymers on Titan

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 965
Author(s):  
Zoé Perrin ◽  
Nathalie Carrasco ◽  
Audrey Chatain ◽  
Lora Jovanovic ◽  
Ludovic Vettier ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Gas Phase ◽  
Formation Process ◽  
Upper Atmosphere ◽  
Gas Mixture ◽  
Space Probe ◽  
Atmospheric Haze ◽  
Formation And Evolution ◽  
Haze Formation

Titan’s haze is strongly suspected to be an HCN-derived polymer, but despite the first in situ measurements by the ESA-Huygens space probe, its chemical composition and formation process remain largely unknown. To investigate this question, we simulated the atmospheric haze formation process, experimentally. We synthesized analogues of Titan’s haze, named Titan tholins, in an irradiated N2–CH4 gas mixture, mimicking Titan’s upper atmosphere chemistry. HCN was monitored in situ in the gas phase simultaneously with the formation and evolution of the haze particles. We show that HCN is produced as long as the particles are absent, and is then progressively consumed when the particles appear and grow. This work highlights HCN as an effective precursor of Titan’s haze and confirms the HCN-derived polymer nature of the haze.

In Situ Optical Analysis of the Gas Phase during the Deposition of Silicon Carbide from Methyltrichlorosilane

1996 ◽  
Vol 143 (5) ◽  
pp. 1654-1661 ◽  
Author(s):  
M. Ganz ◽  
N. Dorval ◽  
M. Lefebvre ◽  
M. Péalat ◽  
F. Loumagne ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Gas Phase ◽  
Optical Analysis

In situ analysis of gas phase reaction processes within monolithic catalyst supports by applying NMR imaging methods

2016 ◽  
Vol 273 ◽  
pp. 91-98 ◽  
Author(s):  
Jürgen Ulpts ◽  
Wolfgang Dreher ◽  
Lars Kiewidt ◽  
Miriam Schubert ◽  
Jorg Thöming
Keyword(s):  
Gas Phase ◽  
In Situ Analysis ◽  
Catalyst Supports ◽  
Nmr Imaging ◽  
Phase Reaction ◽  
Imaging Methods ◽  
Monolithic Catalyst ◽  
Gas Phase Reaction ◽  
Reaction Processes

scholarly journals Open-path, quantum cascade-laser-based sensor for high-resolution atmospheric ammonia measurements

2014 ◽  
Vol 7 (1) ◽  
pp. 81-93 ◽  
Author(s):  
D. J. Miller ◽  
K. Sun ◽  
L. Tao ◽  
M. A. Khan ◽  
M. A. Zondlo
Keyword(s):  
Gas Phase ◽  
Quantum Cascade Laser ◽  
High Temporal Resolution ◽  
Reduced Pressure ◽  
Total Uncertainty ◽  
Atmospheric Ammonia ◽  
Quantum Cascade ◽  
Open Path ◽  
Time Calibration

Abstract. We demonstrate a compact, open-path, quantum cascade-laser-based atmospheric ammonia sensor operating at 9.06 μm for high-sensitivity, high temporal resolution, ground-based measurements. Atmospheric ammonia (NH3) is a gas-phase precursor to fine particulate matter, with implications for air quality and climate change. Currently, NH3 sensing challenges have led to a lack of widespread in situ measurements. Our open-path sensor configuration minimizes sampling artifacts associated with NH3 surface adsorption onto inlet tubing and reduced pressure sampling cells, as well as condensed-phase partitioning ambiguities. Multi-harmonic wavelength modulation spectroscopy allows for selective and sensitive detection of atmospheric pressure-broadened absorption features. An in-line ethylene reference cell provides real-time calibration (±20% accuracy) and normalization for instrument drift under rapidly changing field conditions. The sensor has a sensitivity and noise-equivalent limit (1σ) of 0.15 ppbv NH3 at 10 Hz, a mass of ~ 5 kg and consumes ~ 50 W of electrical power. The total uncertainty in NH3 measurements is 0.20 ppbv NH3 ± 10%, based on a spectroscopic calibration method. Field performance of this open-path NH3 sensor is demonstrated, with 10 Hz time resolution and a large dynamic response for in situ NH3 measurements. This sensor provides the capabilities for improved in situ gas-phase NH3 sensing relevant for emission source characterization and flux measurements.

scholarly journals In Situ FTIR Reactor for Monitoring Gas-Phase Products during a (Photo)catalytic Reaction in the Liquid Phase

2018 ◽  
Vol 90 (24) ◽  
pp. 14586-14592 ◽  
Author(s):  
Igor Telegeiev ◽  
Oumaima Thili ◽  
Adrien Lanel ◽  
Philippe Bazin ◽  
Yoann Levaque ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Gas Phase ◽  
Catalytic Reaction ◽  
In Situ Ftir

scholarly journals A Study of CVD of Gallium Nitride Films by In Situ Gas-Phase UV Spectroscopy

1995 ◽  
Vol 05 (C5) ◽  
pp. C5-183-C5-190 ◽  
Author(s):  
S. E. Alexandrov ◽  
A. Y. Kovalgin ◽  
D. M. Krasovitskiy
Keyword(s):  
Gallium Nitride ◽  
Gas Phase ◽  
Uv Spectroscopy
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