scholarly journals Hydrogen Isotope Fractionation between HCl2- Ion and HCl

1975 ◽  
Vol 30 (1) ◽  
pp. 38-43
Author(s):  
J. Szydłowski
Keyword(s):  
Hydrogen Isotope ◽  
Isotope Fractionation ◽  
Theoretical Calculations ◽  
Harmonic Approximation ◽  
Statistical Thermodynamic ◽  
Large Temperature ◽  
Deuterium Isotope Effect ◽  
Fractionation Factor ◽  
Temperature Dependences ◽  
Good Agreement

Abstract Hydrogen isotope fractionation between hydrogen dichloride ion in the condensed phase and gaseous hydrogen chloride has been studied both theoretically and experimentally. Quite good agreement between the experimental tritium fractionation factor and that theoretically calculated for two sets of vibrational data was found. Theoretical calculations of the fractionation factors of both deuterium and tritium over the large temperature range of 100-2000 K revealed some anomalies (minima and crossover points) in their temperature dependences. The relative tritium-deuterium isotope effect has also been discussed within the framework of the presently accepted statistical-thermodynamic theory in the harmonic approximation and recent works by Stern et al.

Size Effects in Bi-Sb Solid Solutions Thin Films

2011 ◽  
Vol 1314 ◽  
Author(s):  
Elena I. Rogacheva ◽  
Dar’ya S. Orlova ◽  
Mildred S. Dresselhaus ◽  
Shuang Tang
Keyword(s):  
Thin Films ◽  
Solid Solutions ◽  
Room Temperature ◽  
Thermal Evaporation ◽  
Theoretical Calculations ◽  
Thermoelectric Power Factor ◽  
Quantum Oscillations ◽  
Kinetic Coefficients ◽  
Temperature Dependences ◽  
Good Agreement

ABSTRACTThe room-temperature dependences of the electrical conductivity σ, Seebeck coefficient S, Hall coefficient RH, and the thermoelectric power factor P on the thickness (d=10–300 nm) of the thin films grown on mica substrates by thermal evaporation in vacuum of Bi-Sb solid solutions crystals with 4.5 at.% Sb were obtained. It was established that an increase in d up to ~ 200 nm leads to a change in kinetic coefficients and that in the thickness dependences of the thermoelectric properties, quantum oscillations were observed. It was shown that the monotonic component of the σ(T) dependence can be satisfactorily approximated by theoretical calculations based on the classical Fuchs - Sondheimer theory. The theoretically estimated period of oscillations is in a good agreement with the experimentally observed period.

Deviation from Stoichiometry and Lattice Properties of Semiconducting SnTe Phase

1995 ◽  
Vol 378 ◽  
Author(s):  
E. I. Rogacheva ◽  
G. V. Gorne ◽  
O. N. Nashchekina
Keyword(s):  
Thermal Resistance ◽  
Cross Section ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Theoretical Calculations ◽  
Linear Change ◽  
Deviation From Stoichiometry ◽  
Temperature Dependences ◽  
Thermal Conductivity Λ ◽  
Good Agreement

AbstractThe temperature dependences of lattice thermal conductivity λp in the range of 300-650 K were obtained for SnTe1+x semiconducting phase with x =0-0.04. It is established that the nonstoichiometric vacancies are centers of effective scattering of phonons. The scattering cross-section calculated from experimental data is in a good agreement with the theoretical calculations based on the Klemens theory. The linear change of thermal resistance with temperature is observed, which evidences the prevalence of three-phonon scattering processes. The additional thermal resistance grows as the concentration of cation vacancies increases.

Photoluminescence Processes in the Triplet State of Phosphorescent Organic Materials: Ir(ppy)3 Doped in TPD

2006 ◽  
Vol 517 ◽  
pp. 173-182
Author(s):  
Nadeer Aljaroudi ◽  
Taiju Tsuboi
Keyword(s):  
Triplet State ◽  
Room Temperature ◽  
Theoretical Calculations ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Energy Diffusion ◽  
Temperature Dependences ◽  
Level Model ◽  
Pl Intensity ◽  
Good Agreement

Photoluminescence (PL) measurements have been made for a spin-coated thin film of phosphorescent tris(2-phenylpyridine) iridium [Ir(ppy)3] doped in N,N’-bis (3-methylphenyl)-N, N’-bis(phenyl)-benzidine (TPD) host material in the temperature range from 10 K to room temperature. When temperature is increased from 10 K to 300 K, the PL intensity of Ir(ppy)3 increases from 10 K and decreases above about 200 K. Theoretical calculations are undertaken for the temperature dependence using (1) a three-level model where three zero-field splitting substates are generated in the triplet state of Ir(ppy)3 and (2) endothermic energy transfer from the TPD host to the Ir(ppy)3 guest, and (3) energy diffusion from the excited TPD to the neighboring unexcited TPD. A good agreement was obtained between the measured and calculated temperature dependences of the PL intensity.

On the Viscosity and Physical Origin of Stability of Weakly Bound Complexes CdZn, HgZn and HgCd

2007 ◽  
Vol 72 (3) ◽  
pp. 363-378 ◽  
Author(s):  
Michal Ilčin ◽  
Vladimír Lukeš ◽  
Viliam Laurinc ◽  
Stanislav Biskupič
Keyword(s):  
Shear Viscosity ◽  
Theoretical Calculations ◽  
Van Der Waals Complexes ◽  
Physical Origin ◽  
Weakly Bound ◽  
Hartree Fock ◽  
Weakly Bound Complexes ◽  
Temperature Dependences ◽  
Electronic Ground ◽  
Good Agreement

Supermolecular CCSD(T) ab initio calculations of potential energy curves for the electronic ground states of heteronuclear van der Waals complexes formed from the atoms of IIB group are presented. The physical origin of stability of the studied structures was analyzed by the symmetry-adapted perturbation theory. The magnitude of dispersion term increases with the increase of diatomic mass, but the relative importance of dispersion vs Hartree- Fock induction energies decreases in the order CdZn > HgZn > HgCd. Theoretical calculations of the temperature dependence of the shear viscosity for low-density binary mixtures are in good agreement with the temperature dependences of the shear viscosity obtained from empirical formula.

Hydrogen isotope fractionation between methanol and diphenylphosphine or dimethylphosphine in the gas phase and in aprotic solvents

1996 ◽  
Vol 74 (8) ◽  
pp. 1465-1469
Author(s):  
Andrzej Wawer ◽  
Jerzy Szydtlowski
Keyword(s):  
Interaction Energy ◽  
Gas Phase ◽  
Hydrogen Isotope ◽  
Isotope Fractionation ◽  
Isotope Effects ◽  
Solvent Polarity ◽  
Exchange Reactions ◽  
Fractionation Factor ◽  
The Given ◽  
Fractionation Factors

D/H fractionation factors between MeOH and Ph2PH in dilute solutions of tetrachloroethylene, benzene, tetrahydrofuran, pyridine, and acetonitrile and T/H fractionation factors between MeOH and Me2PH vapors were measured. The experimental results agree very well with values calculated from the statistical theory of isotope effects formulated by Bigeleisen and Mayer. There are correlations between observed fractionation factors and solvent polarity, and the interaction energy of methanol with the given solvent. Another correlation has been found between enthalpy of the exchange reactions and the interaction energy between methanol and the given solvent. Key words: isotope effects, fractionation factor, diphenylphosphine, methanol.

MACROSCOPIC QUANTUM TUNNELING IN A SUPERCONDUCTING RING CONTAINING A WEAK SUPERCONDUCTING JUNCTION

1992 ◽  
Vol 06 (24) ◽  
pp. 1501-1511
Author(s):  
A. EXTREMERA
Keyword(s):  
Theoretical Calculations ◽  
Minimum Energy ◽  
Standard Form ◽  
Harmonic Approximation ◽  
Macroscopic Quantum ◽  
Superconducting Ring ◽  
Mathieu’S Equation ◽  
Superconducting Junction ◽  
Macroscopic Quantum Effects ◽  
Good Agreement

Macroscopic quantum effects in SQUIDs are discussed. An equation describing the behavior of the superconducting ring in the harmonic approximation is reduced to the standard form of Mathieu’s equation. For well-defined flux states, good agreement with exact theoretical calculations and experimental results is found near the minimum energy regions. We establish the effective dissipation dependence on tunneling rate via the “instanton” or “bounce” action. WKB-type approximations enable us to obtain the quantum decay rate for a metastable state in the anharmonic (quartic) potential.

Theoretical and experimental research on slip and uplift of the timber-concrete composite beam

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 7079-7099
Author(s):  
Jianying Chen ◽  
Guojing He ◽  
Xiaodong (Alice) Wang ◽  
Jiejun Wang ◽  
Jin Yi ◽  
...  
Keyword(s):  
Differential Equations ◽  
Deformation Theory ◽  
Concrete Slab ◽  
Theoretical Calculations ◽  
Structural Element ◽  
Structural Efficiency ◽  
Theoretical Investigations ◽  
New Type ◽  
Interlayer Slip ◽  
Good Agreement

Timber-concrete composite beams are a new type of structural element that is environmentally friendly. The structural efficiency of this kind of beam highly depends on the stiffness of the interlayer connection. The structural efficiency of the composite was evaluated by experimental and theoretical investigations performed on the relative horizontal slip and vertical uplift along the interlayer between composite’s timber and concrete slab. Differential equations were established based on a theoretical analysis of combination effects of interlayer slip and vertical uplift, by using deformation theory of elastics. Subsequently, the differential equations were solved and the magnitude of uplift force at the interlayer was obtained. It was concluded that the theoretical calculations were in good agreement with the results of experimentation.

scholarly journals Unravelling the process of petroleum hydrocarbon biodegradation in different filter materials of constructed wetlands by stable isotope fractionation and labelling studies

2021 ◽  
Author(s):  
Andrea Watzinger ◽  
Melanie Hager ◽  
Thomas Reichenauer ◽  
Gerhard Soja ◽  
Paul Kinner
Keyword(s):  
Stable Isotope ◽  
Constructed Wetlands ◽  
Hydrogen Isotope ◽  
Petroleum Hydrocarbon ◽  
Isotope Fractionation ◽  
Isotope Effects ◽  
Filter Material ◽  
Hydrocarbon Biodegradation ◽  
Stable Isotope Fractionation ◽  
Filter Materials

AbstractMaintaining and supporting complete biodegradation during remediation of petroleum hydrocarbon contaminated groundwater in constructed wetlands is vital for the final destruction and removal of contaminants. We aimed to compare and gain insight into biodegradation and explore possible limitations in different filter materials (sand, sand amended with biochar, expanded clay). These filters were collected from constructed wetlands after two years of operation and batch experiments were conducted using two stable isotope techniques; (i) carbon isotope labelling of hexadecane and (ii) hydrogen isotope fractionation of decane. Both hydrocarbon compounds hexadecane and decane were biodegraded. The mineralization rate of hexadecane was higher in the sandy filter material (3.6 µg CO2 g−1 day−1) than in the expanded clay (1.0 µg CO2 g−1 day−1). The microbial community of the constructed wetland microcosms was dominated by Gram negative bacteria and fungi and was specific for the different filter materials while hexadecane was primarily anabolized by bacteria. Adsorption / desorption of petroleum hydrocarbons in expanded clay was observed, which might not hinder but delay biodegradation. Very few cases of hydrogen isotope fractionation were recorded in expanded clay and sand & biochar filters during decane biodegradation. In sand filters, decane was biodegraded more slowly and hydrogen isotope fractionation was visible. Still, the range of observed apparent kinetic hydrogen isotope effects (AKIEH = 1.072–1.500) and apparent decane biodegradation rates (k = − 0.017 to − 0.067 day−1) of the sand filter were low. To conclude, low biodegradation rates, small hydrogen isotope fractionation, zero order mineralization kinetics and lack of microbial biomass growth indicated that mass transfer controlled biodegradation.

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