scholarly journals A Calorimetric Study on the Relative Thermal Stability of Some Bis(diamine)cobalt(III) Complexes in a Solid Phase

1983 ◽  
Vol 56 (8) ◽  
pp. 2250-2253 ◽  
Author(s):  
Ryokichi Tsuchiya ◽  
Akira Uehara ◽  
Toshio Wazumi ◽  
Yoshinori Muramatsu
Keyword(s):  
Thermal Stability ◽  
Solid Phase ◽  
Calorimetric Study ◽  
Relative Thermal Stability ◽  
Thermal Stability Of

The relative thermal stability of polymer model compounds

1962 ◽  
Vol 6 (19) ◽  
pp. 47-56 ◽  
Author(s):  
Desmond Sheehan ◽  
Alan P. Bentz ◽  
John C. Petropoulos
Keyword(s):  
Thermal Stability ◽  
Polymer Model ◽  
Model Compounds ◽  
Relative Thermal Stability ◽  
Thermal Stability Of

Thermal stability of Mg 2 Si epitaxial film formed on Si (111) substrate by solid phase reaction

2009 ◽  
Vol 18 (7) ◽  
pp. 3079-3083 ◽  
Author(s):  
Wang Xi-Na ◽  
Wang Yong ◽  
Zou Jin ◽  
Zhang Tian-Chong ◽  
Mei Zeng-Xia ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Epitaxial Film ◽  
Solid Phase ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Thermal Stability Of

scholarly journals The Thermal Stability of the Naphthalene Sulfonic Acids Under Geothermal Conditions

2021 ◽  
Author(s):  
◽  
Lucjan Sajkowski
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
High Temperatures ◽  
Solid Phase ◽  
Atmospheric Oxygen ◽  
Pure Water ◽  
Pressure Vessels ◽  
Geothermal Reservoirs ◽  
Flow Through ◽  
Thermal Stability Of

<p>A primary goal of this thesis was to obtain kinetic data on the breakdown and isomerisation reactions of naphthalene disulfonate (NDS) and naphthalene sulfonate (NSA) compounds under geothermal conditions. A secondary aim of this study was to investigate NDS/NSA isomerisation transformations as well as to study their kinetics and identify products of thermal disproportionation. Because of their apparent thermal stability, naphthalene disulfonate solutions have been frequently injected into active geothermal reservoirs and their subsequent detection (“recovery”) in nearby wells/bore holes used as an indicator of well connectivity and local permeability. The results obtained in this thesis will enable a more insightful interpretation of field injection results and fluid flow in active geothermal reservoirs. The studies presented in this thesis were designed to determine the thermal stability of aqueous NDS and NSA at high temperatures from 100 to 400°C in pure water and different salt solutions (i.e. NaCl +/- Na2SO4 and Na2S) at saturated vapour pressure. The stabilities and isomerisation transformations of NDS and NSA were also studied in the presence of solid materials (i.e. quartz, greywacke, pumice) which may occur in the host geological environment of hydrothermal/geothermal reservoirs in the Earth’s crust. Dilute aqueous solutions of NDS and NSA were contained in sealed silica glass ampoules (purged of atmospheric oxygen) and placed in stainless steel pressure vessels and heated for varying times to the desired high temperatures. Additional experiments were also conducted in which dilute NDS and NSA solutions were pumped from a de-oxygenated reservoir container through a flow-through autoclave containing different rock and mineral phases at temperatures up 400°C. The resulting NDS and NSA isomers were then analysed using HPLC and GC-MS methodologies. The 1,5-naphthalene disulfonate isomer (1,5-NDS) was found to be the least stable at pHt = 3 - 8 and readily transformed to 1-naphthalene sulfonate (1-NSA) at t ≥ 200°C. The 2-NSA was found to be the most stable isomer but disappeared at t ≥ 300°. The experimental data indicated that the stabilities of all the NDS and NSA studied as a function of temperature, pH and salt (NaCl) concentration were in the sequence: 1,5-NDS < 1,6-NDS < 2,6-NDS ≈ 2,7-NDS < 2-NSA. The presence of dissolved salts was shown to slow down the decomposition rates. Results from flow-through autoclave experiments suggest that between 100 and 250°C, the stabilities of 2,6-NDS, 2,7-NDS, 1,5-NDS and 1,6-NDS are mainly controlled by solution pH, while at t ≥ 300°C, temperature is the main stability controlling factor. Additionally, no adsorption of NDS/NSA on the surface of minerals was observed. A new high-performance liquid chromatography (HPLC) method combined with solid-phase extraction (SPE) was developed to enable detection of NDS/NSA breakdown products at t ≥ 300°C. In hydrothermal solutions at temperatures greater than 300°C, all the naphthalene sulfonate isomers become unstable with the formation naphthalene (NAP) and the two naphthol isomers, 1-naphthol (1-NAP) and 2-naphthol (2-NAP), as confirmed by both the new HPLC/SPE method and GC-MS (gas chromatography–mass spectroscopy). In addition, 1-chloronaphthalene was also detected (using GC-MS) as a high temperature reaction product NDS/NSA disproportionation in 0.05 m NaCl solutions. The results of the experiments carried out during this thesis indicate that the stabilities the naphthalene mono- and disulfonates are a function of temperature, pH and salt concentration. The naphthalene sulfonates transform to different isomers and the kinetics of these isomerisation reactions have been determined. At temperatures ≥ 300°C, the NDS and NSA compounds disproportionate to the naphthalene “backbone” molecule as well as to the two stable naphthols and 1-chloronaphthalene (in chloride containing solutions). The application of naphthalene sulfonates to determine well connectivity and local permeabilities in active geothermal reservoirs is thus rather more complicated than previously appreciated. An understanding of the various isomer transformations and their kinetics is required. Furthermore, naphthalene sulfonates injected into high temperature geothermal reservoirs are unstable and breakdown to naphthalene, naphthols and probable halogenated naphthalene compounds, none of which have been considered in the interpretation of NDS/NSA recovery data in active geothermal reservoirs. The thermal stabilities of NAP, 1- and 2-NAP and 1-chloronaphthalene indicate that these compounds may also be employed as connectivity tracers in high temperature (t ≥ 300°C) systems.</p>

Implant Isolation of Device Structures Containing Buried, Highly-Doped Layers

1990 ◽  
Vol 216 ◽  
Author(s):  
S. J. Pearton ◽  
F. Ren ◽  
L. A. D'Asaro ◽  
W. S. Hobson ◽  
T. R. Fullowan ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Deep Level ◽  
Dose Range ◽  
Hydrogen Ion ◽  
Current Gain ◽  
High Resistivity ◽  
Device Structures ◽  
Hydrogen Ion Implantation ◽  
Relative Thermal Stability ◽  
Thermal Stability Of

ABSTRACTThe formation of high resistivity (> 107 Ω□) regions in GaAs-AlGaAs HBT and SEED structures by oxygen and hydrogen ion implantation is described. Multiple energy implants in the dose range 1013 cm−3 (for O+) and 1015 cm−2 (for H+), followed by annealing around 500°C are necessary to isolate structures ∼2 μm thick. In each case, the evolution of the sheet resistance of the implanted material with annealing is consistent with a reduction in hopping probabilities of trapped carriers between deep level states for temperatures up to ∼600°C, followed by significant annealing of these deep levels. A comparison of the relative thermal stability of O+ or H+ ion implantisolated p+ material is given. Small geometry (2 × 9 μm2) HBTs exhibiting current gain of 44 and cut-off frequency fT as high as 45 GHz are demonstrated using implant isolation.

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