Electron recombination and diffusion in CO at elevated temperature

1969 ◽  
Vol 47 (17) ◽  
pp. 1789-1795 ◽  
Author(s):  
Michael H. Mentzoni ◽  
James Donohoe
Keyword(s):  
Room Temperature ◽  
Diagnostic Techniques ◽  
Zero Field ◽  
Time Decay ◽  
Electron Recombination ◽  
Average Temperature ◽  
Field Mobility ◽  
Ion Recombination ◽  
Pressure Interval ◽  
And Diffusion

The electron time decay in an afterglow following a short pulsed d.c. discharge in CO has been investigated using microwave diagnostic techniques. The gas was heated to an average temperature of 775 °K. Two-body electron-ion recombination and ambipolar diffusion were found to be the only important electron removal mechanisms present in the pressure interval [Formula: see text] Torr with the rate constants αr = 3.9 × 10−7 cm3 s−1 and Dap0 = 372 cm2 s−1 Torr respectively. If we postulate a T−γ dependence for αr, comparison with room temperature results yields γ = 0.57. The diffusion coefficient appears to increase strongly with temperature based upon an estimated zero field mobility for CO+in CO at 273 °K found in the literature.

Hot-electron zero-field mobility and diffusion in rare-gas moderators

1985 ◽  
Vol 31 (3) ◽  
pp. 1894-1905 ◽  
Author(s):  
Darryl R. A. McMahon ◽  
Bernie Shizgal
Keyword(s):  
Rare Gas ◽  
Zero Field ◽  
Hot Electron ◽  
Field Mobility ◽  
And Diffusion

The EPR Zero-Field Splitting D and its Pressure and Temperature Dependence for Trigonal Mn2+ Centers in [Zn(H2O)6](BF4)2:Mn2+ Crystal

2006 ◽  
Vol 61 (5-6) ◽  
pp. 289-292 ◽  
Author(s):  
Hong-Gang Liu ◽  
Xiao-Xuan Wu ◽  
Wen-Chen Zheng ◽  
Lv He
Keyword(s):  
Temperature Dependence ◽  
Room Temperature ◽  
Coupling Mechanism ◽  
Zero Field ◽  
Spin Orbit Coupling ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Thermal Expansion Coefficients ◽  
Perturbation Formula ◽  
Expansion Coefficients

The EPR zero-field splitting D (= b02 ) and its pressure and temperature dependence for trigonal Mn2+ centers in low and room temperature phases in [Zn(H2O)6](BF4)2 :Mn2+ crystal are studied by a high-order perturbation formula based on the dominant spin-orbit coupling mechanism. From the studies, the local trigonal distortion angles, the local angular compressibilities and the local angular thermal expansion coefficients for Mn2+ centers in both phases of the [Zn(H2O)6](BF4)2 crystal are estimated. The results are discussed

scholarly journals Limiting the Oxidation of WS2 Nanostructures by Oleylamine Surface Passivation for Room Temperature NH3 Sensing

2020 ◽  
Author(s):  
Siziwe Gqoba ◽  
Rafael Rodrigues ◽  
Sharon Lerato Mphahlele ◽  
Zakhele Ndala ◽  
Mildred Airo ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Room Temperature ◽  
Surface Passivation ◽  
Electrical Response ◽  
Prolonged Incubation ◽  
P Type ◽  
2D Nanosheets ◽  
Type Response ◽  
And Diffusion ◽  
Hierarchical Morphology

Oleylamine capped WS2 nanostructures were successfully formed at 320 °C via a relatively simple colloidal route. SEM and TEM analyses showed that the 3D nanoflowers that were initially formed disintegrated into 2D nanosheets after prolonged incubation. XPS and XRD analyses confirmed oxidation of WS2 into WO3. Sensors based on these oleylamine capped WS2 nanoflowers and nanosheets still showed a change in electrical response towards various concentrations of NH3 vapour at room temperature in a 25% relative humidity background despite the oxidation. The nanoflowers exhibited n-type response while the nanosheets displayed a p-type response towards NH3 exposure. The nanoflower based sensors showed better response to NH3 vapour exposure than the nanosheets. The sensors showed a good selectivity towards NH3 relative to acetone, ethanol, chloroform and toluene. Meanwhile, a strong interference of humidity to the NH3 response was displayed at high relative humidity levels. The results demonstrated that oleylamine limited the extent of oxidation of WS2 nanostructures. The superior sensing performance of the nanoflowers can be attributed to their hierarchical morphology which enhances the surface area and diffusion of the analyte.

scholarly journals COLD TOLERANCE OF BANANA FRUITS OF DIFFERENT CULTIVARS

2016 ◽  
Vol 29 (3) ◽  
pp. 629-641 ◽  
Author(s):  
JOÃO ALISON ALVES OLIVEIRA ◽  
LUIZ CARLOS CHAMHUM SALOMÃO ◽  
DALMO LOPES DE SIQUEIRA ◽  
PAULO ROBERTO CECON
Keyword(s):  
Relative Humidity ◽  
Low Temperature ◽  
Cold Storage ◽  
Room Temperature ◽  
Storage Time ◽  
Chilling Injury ◽  
Titratable Acidity ◽  
Soluble Solids ◽  
Average Temperature ◽  
C Storage

ABSTRACT The objective of this work was to evaluate the tolerance of fruits of different banana cultivars to low temperature storages. Fruits of the cultivars Nanicão (AAA), Prata (AAB), Vitória (AAAB), Maçã (AAB) and Caipira (AAA) were used. Clusters of three fruits were kept in cold storage for 7, 14 and 21 days, with average temperature of 10.53±0.37°C and relative humidity of 85%. Subsequently, the clusters were transferred to temperatures of 22±0.39°C and evaluated for 16 days. The fruits of all cultivars remained green after 21 days of storage at 10.53±0.37°C. Fruits of the cultivar Nanicão did not completely ripened after transferred to the 22°C storage, when stored for 7 days at low temperature. These fruits were firmer, with green peel and low soluble solids and titratable acidity. The fruits of all cultivars complete the ripening when transferred to room temperature after 21 days of cold storage. Chilling injuries increased with cold storage time in all cultivars. The cultivars Nanicão, Caipira and Maçã had more symptoms of chilling injury, while Prata and Vitória were more tolerant to the cold storage (10.53°C) for up to 21 days, showing normal ripening after transferred to the 22±0.39°C storage.

scholarly journals Enhancement of zero-field skyrmion density in [Pt/Co/Fe/Ir]2 multilayers at room temperature by the first-order reversal curve

2020 ◽  
Vol 127 (22) ◽  
pp. 223901 ◽  
Author(s):  
Mangyuan Ma ◽  
Calvin Ching Ian Ang ◽  
Yong Li ◽  
Zizhao Pan ◽  
Weiliang Gan ◽  
...  
Keyword(s):  
Room Temperature ◽  
Zero Field ◽  
First Order

scholarly journals The Coordination Chemistry of Phosphoryl Compounds Containing the -N(CH3)2 Group, XII.

1973 ◽  
Vol 28 (3-4) ◽  
pp. 104-106 ◽  
Author(s):  
M.W.G. De Bolster ◽  
B. Nieuwenhuijse ◽  
J. Reedijk
Keyword(s):  
Electron Spin Resonance ◽  
Metal Ion ◽  
Room Temperature ◽  
Esr Spectroscopy ◽  
Hyperfine Coupling ◽  
Hyperfine Coupling Constant ◽  
Zero Field ◽  
Coupling Constant ◽  
Spin Resonance ◽  
Temperature Electron

Room temperature electron spin resonance powder spectra have been recorded for some compounds of the type Mn(ligand)p(anion)2 with hexamethylphosphoramide and nonamethylimidodiphosphoramide as ligands (p = 1 - 4) and BF-4, NO-3, Cl-, Br-, I- and NCS-as anions.The values for the zero-field parameters, D and λ, have been determined and are compared with literature data. It is shown that ESR spectroscopy can be very helpful in elucidating the structures of manganese(II) complexes.The high values for the hyperfine coupling constant of the solvates suggest that in these complexes the bonding between the ligands and the metal ion is essentially ionic.

scholarly journals Synthesis of Sn/Ag–Sn nanoparticles via room temperature galvanic reaction and diffusion

RSC Advances ◽  
2019 ◽  
Vol 9 (38) ◽  
pp. 21786-21792 ◽  
Author(s):  
Min Jia Saw ◽  
Mai Thanh Nguyen ◽  
Shilei Zhu ◽  
Yongming Wang ◽  
Tetsu Yonezawa
Keyword(s):  
Intermetallic Compound ◽  
Room Temperature ◽  
And Diffusion ◽  
Reaction And Diffusion

Coating of Ag–Sn intermetallic compound on Sn nanoparticles at room temperature.

scholarly journals Deposits of iron oxides in the human globus pallidus

Open Physics ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 291-298
Author(s):  
Helena Svobodová ◽  
Jana Hlinková ◽  
Pavol Janega ◽  
Daniel Kosnáč ◽  
Barbora Filová ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Human Brain ◽  
Iron Oxides ◽  
Globus Pallidus ◽  
Room Temperature ◽  
Hysteresis Loops ◽  
Point Of View ◽  
Zero Field ◽  
Fixed Temperature ◽  
Transmission Electron

Abstract Samples taken from the human brain (Globus Pallidus) have been investigated by physical techniques such as light microscopy, scanning electron microscopy, transmission electron microscopy, Mössbauer spectroscopy and SQUID magnetometry. SEM-EDX/TEM investigation reveals multielemental composition of hematite and magnetite nanocrystals with sizes ranging from 40 nm to 100 nm and hematite microcrystals from 3 μm to 7 μm. Room temperature Mössbauer spectra show quadrupole doublets assigning to hematite and ferrihydrite. SQUID measurements of temperature dependence of the mass magnetic susceptibility between T = 2 – 300 K at DC field B0 = 0.1 T, the field dependence of the mass magnetization taken at the fixed temperature T0 = 2.0 and 4.6 K and the zero-field cooled and field cooled magnetization experiments (ZFCM/FCM) confirm a presence of ferrimagnetic phases such as maghemite and/or magnetite with hysteresis loops surviving until the room temperature. Differences between these measurements from the point of view of iron oxides detected can indicate important processes in human brain and interactions between ferritin as a physiological source of iron and surrounding environment.

Geminate-ion kinetics with competing ion fragmentation in nonpolar liquids with halocarbons

1990 ◽  
Vol 68 (9) ◽  
pp. 918-924 ◽  
Author(s):  
Rolf E. Bühler
Keyword(s):  
Low Temperatures ◽  
Pulse Radiolysis ◽  
Room Temperature ◽  
Ion Concentration ◽  
Geminate Recombination ◽  
Rate Law ◽  
Ion Fragmentation ◽  
Nonpolar Liquids ◽  
Ion Recombination ◽  
Semi Empirical

The semi-empirical rate law for geminate-ion recombination by van den Ende, Warman, and Hummel, which predicts a linear dependence of the ion concentration with t−0.6, is modified to include simultaneous ion fragmentation. The theory is applied to the kinetics, as observed by pulse radiolysis of liquid methylcyclohexane (MCH) solutions of N2O, CHCl3, or tert-butylchloride (t-BuCl) at low temperatures. In MCH saturated with N2O (−130 °C), the solvent cation (MCH+, λmax = 550 nm) moves about 400 times faster than prediced by diffusion. With the known conductivity data at room temperature, an activation energy of about 2.7 kJ/mol can be derived. The solvent cation MCH+ does not appear to fragment. With t-BuCl added to MCH (−134 °C), MCH+ (λmax = 550 nm) and t-BuCl− (λmax = 450 nm) are observed simultaneously. The initial kinetics corresponds to the parent ion (MCH+) recombination with t-BuCl−. Then the MCH+ fragmentation with k1(−134 °C) = 3 × 105 s−1 is observed, followed by the geminate recombination of some fragment cation with t-BuCl−. The fragment cation recombines 300 times slower than the parent cation. With CHCl3 added to MCH (−130 °C), the MCH+ absorption is hidden within the [Formula: see text] band (λmax = 470 nm); however, the fragmentation is detected from kinetic analysis to occur in about 2 × 106 s−1. The modified t−0.6 rate law appears to be a very useful tool to study simultaneous ion recombination and ion fragmentation.

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