Determination of the temperature of air and the Earth's underlying surface in model calculations of methane content in the atmosphere

2021 ◽  
Vol 34 (9) ◽  
pp. 711-715
Author(s):  
S.A. Shishigin
Keyword(s):  
Methane Content ◽  
Underlying Surface ◽  
Model Calculations

Statistical Description of Isotope Exchange Processes: A Multisite Model for the 18O Exchange

1982 ◽  
Vol 37 (11-12) ◽  
pp. 1161-1169 ◽  
Author(s):  
Paul Rösch
Keyword(s):  
Active Site ◽  
Isotope Exchange ◽  
Analytical Procedure ◽  
Matrix Formalism ◽  
Model Calculations ◽  
Exchange Processes ◽  
Reaction Solution ◽  
Different Types ◽  
Refinement Procedure

Abstract An analytical procedure has been developed for the determination of isotope exchange processes as exemplified by the 18O exchange catalysed by enzyme-nucleotide complexes. The model is able to handle more than one type of active site per reaction solution and is also able to distinguish between different types of inequivalence of the oxygens of enzyme bound Pi. Use of transition matrix formalism and basic statistical considerations lead directly to the simple model. A data refinement procedure is introduced and model calculations are shown.

An Analytical Description of the Magnetic Conductance Across an Isolated Defect Region in a 1D-Ferromagnetic Lead

SPIN ◽  
2019 ◽  
Vol 09 (01) ◽  
pp. 1950005 ◽  
Author(s):  
Adel Belayadi ◽  
Boualem Bourahla ◽  
Ahmed Mougari
Keyword(s):  
Contact Region ◽  
Analytical Description ◽  
Quantum Scattering ◽  
Defect Region ◽  
Model Calculations ◽  
Adopted Model ◽  
Field Matching ◽  
Ferromagnetic Lead ◽  
Transmission And Reflection

We illustrate in this contribution the determination of the magnetic conductance across a nanocontact region defined by an isolated defect region joined between two mono-atomic leads ferromagnetically ordered. The system is described by the Heisenberg interaction. Additionally, to deal with the lack of symmetry across the contact region defined by the isolated defect, we involve the phase field matching approach. Furthermore, to compute the quantum conductance, we define the quantum scattering of the transmission and reflection probabilities within the framework of Landauer–Büttiker formalism. Based on these approaches, we present an analytical expression of the magnetic conductance. The obtained analytical results based on our adopted procedures confirm the known results adopted for perfect infinite leads (no defect). Our model calculations can be applied numerically when we deal with doping across the defect region. The adopted model could be also used numerically to deal with the impurity configurations that one might encounter in real systems.

scholarly journals ββ DECAY AND NUCLEAR STRUCTURE

2007 ◽  
Vol 16 (02) ◽  
pp. 552-560 ◽  
Author(s):  
E. CAURIER ◽  
F. NOWACKI ◽  
A. POVES
Keyword(s):  
Shell Model ◽  
Nuclear Matrix ◽  
Large Scale ◽  
Predictive Power ◽  
Strong Impact ◽  
Matrix Elements ◽  
Model Calculations ◽  
Mode Stability ◽  
Recent Developments

The determination of accurate nuclear matrix elements for ββ decay processes is a challenge for nuclear theory and can have a strong impact in neutrino physics. Large Scale Shell Model (LSSM) calculations are among the best tools for such determination and recent developments have allowed to extend its application domains. In particular, systematic studies of nuclear matrix elements calculations have been now undertaken in this framework for most of the ββ emitters. These calculations are crucial in the determination of the most favorable emitters in the forthcoming generation of ββ experiments. The present paper focuses on the recent advances and remaining difficulties of shell model calculations for the neutrinoless mode. Stability and predictive power of the results will be discussed.

scholarly journals Determination of the Material Relative Permittivity in the UHF Band by Using T and Modified Ring Resonators

2016 ◽  
Vol 62 (2) ◽  
pp. 129-134 ◽  
Author(s):  
Piotr Jankowski-Mihułowicz ◽  
Wojciech Lichoń ◽  
Grzegorz Pitera ◽  
Mariusz Węglarski
Keyword(s):  
Relative Permittivity ◽  
Software Tool ◽  
Test Sample ◽  
Ring Resonators ◽  
Model Calculations ◽  
Electronic Products ◽  
Materials Used ◽  
Permittivity Measurements ◽  
Uhf Band

Abstract The complete methodology of designing T- and modified ring resonators in the UHF band are presented in the paper. On the basis of proposed algorithms, the dedicated software tool has been elaborated in order to determine material parameters of contemporary substrates. The program is implemented in the Mathcad environment and it includes the base of information on known materials used in electronic products. Also, test sample series for selected substrate materials (IS680, FR408, I-SPEED PCB ISOLA and A6-S LTCC FERRO) and operating frequencies from 1 GHz to 3 GHz are analyzed in details. The special test stand with a vector network analyzer has been applied in experiments. The obtained data of relative permittivity measurements and model calculations are described, discussed and concluded.

scholarly journals Tuning the Re/Os Clock: Stellar-Neutron Cross Sections

2009 ◽  
Vol 26 (3) ◽  
pp. 250-254 ◽  
Author(s):  
A. Mengoni ◽  
M. Mosconi ◽  
K. Fujii ◽  
F. Käppeler ◽  
Keyword(s):  
Cross Sections ◽  
Reaction Rates ◽  
Experimental Information ◽  
Nuclear Model ◽  
Time Duration ◽  
Model Calculations ◽  
Neutron Time ◽  
Neutron Cross Sections ◽  
Capture Cross Sections

AbstractThe neutron-capture cross sections of 186,187Os have been recently measured at the CERN neutron time-of-flight facility n_TOF for an improved evaluation of the Re/Os cosmo-chronometer. This experimental information was complemented by nuclear model calculations for obtaining the proper astrophysical reaction rates at s-process temperatures. The calculated results and their implications for the determination of the time-duration of nucleosynthesis during galactic chemical evolution is discussed.

First Principles Computer Simulation of the Defect Chemistry of Rutile TiO2

1996 ◽  
Vol 453 ◽  
Author(s):  
I. Dawson ◽  
P. D. Bristowe ◽  
J. A. White ◽  
M. C. Payne
Keyword(s):  
First Principles ◽  
Formation Energy ◽  
Experimental Studies ◽  
Parallel Computer ◽  
Model Calculations ◽  
Interesting Insight ◽  
First Results ◽  
Dominant Point ◽  
Defect Mechanism

AbstractThere exists a long-standing controversy concerning the nature of the dominant point defect mechanism in rutile TiO2. Previous classical shell model calculations by Catlow el al [1] find a strong preference for Schottky as opposed to Frenkel-type defects, lending support for oxygen vacancy rather than titanium interstitial compensation in reduced rutile. However, reviews of experimental studies [2], show that many conflicting conclusions have been reached. Ab initio total-energy calculations have been performed on a parallel computer to help resolve this controversy. First results indicate a Schottky formation energy (of the bound Schottky trio) consistent with the Mott-Littleton values of Catlow et al [1]. A first attempt is made at calculating the heat of reduction through determination of the formation energy of a neutral oxygen atom vacancy. As a. result some interesting insight is gained into the redox chemistry of reduced rutile.

scholarly journals The calculation of Binding Energy and Incompressibility, Pressure, and Velocity of Sound of Infinite Nuclear matter Using New One Boson Interaction.

2019 ◽  
Vol 1 ◽  
pp. 288-293
Author(s):  
M T Aper ◽  
F Gbaorun ◽  
J O Fiase
Keyword(s):  
Binding Energy ◽  
Nuclear Matter ◽  
Effective Interaction ◽  
Research Work ◽  
Nucleon Nucleon ◽  
Matrix Approach ◽  
Velocity Of Sound ◽  
Model Calculations ◽  
Effective Interactions

The use of effective nucleon – nucleon (N N) interactions for the determination of nuclear matter properties such as, binding energy per nucleon, incompressibility,K of infinite nuclear matter, pressure 0 and velocity of sound of nuclear matter has been a subject of great interest to nuclear physicists for many decades. The effective interaction usually involved in these calculations has been the Michigan three Yukawa (M3Y) effective interactions whose origin is from G- matrix approach. In this research work however, we have used a newly developed interaction known as new one boson (NOB) effective interaction to carry out similar calculations. This new interaction is based on the Lowest Order Constrained Variational (LOCV) technique. The interaction reproduces the saturation energy of spin and isospin infinite nuclear matter of approximately -16MeV at the normal nuclear matter saturation density consistent with the best available density-dependent interaction derived from the G-matrix approach. The results of the incompressibility obtained using the NOB interaction ranges from 304 to 309 MeV. These values are in good agreement with the values of incompressibility obtained for similar calculations using the M3Y – Reid effective interaction, in which values for K range from 304 to 310 MeV. The results of 0 pressure and velocity of sound of infinite nuclear matter obtained in the present calculations are also in excellent agreement with results of other workers. The results of our present calculations indicate that, the NOB interaction has passed the basic test for an effective interaction. The NOB may therefore be applied to other nuclear matter and optical model calculations to ascertain its reliability.

scholarly journals The Expected behaviour of the Hydrogen Lyman Lines in Solar Flares

1972 ◽  
Vol 14 ◽  
pp. 824-824
Author(s):  
Z. Švestka ◽  
L.D. De Feiter
Keyword(s):  
Electron Density ◽  
Solar Flares ◽  
Line Profiles ◽  
Stark Broadening ◽  
Hydrogen Atoms ◽  
Measured Intensity ◽  
Balmer Series ◽  
Model Calculations ◽  
Intensity Measurements

While the merging of the higher lines of the Balmer series emitted by solar flares is solely determined by the electron density, the merging of the high Lyman lines is determined both by the electron density, through Stark broadening of the line absorption coefficient, and by the total number of hydrogen atoms in the flare, through the effect of self-absorption. Preliminary results of model calculations indicate that two or more intensity measurements, each midway between two consecutive lines of the Lyman series (lines 3–4, 4–5, 5–6) allow the determination of the column density of hydrogen atoms in the ground state provided that the electron density is known. One can believe that in between the Lyman lines only the flare elements contribute to the measured intensity since excited interflare matter of much lower electron density produces line profiles of substantially smaller width. Thus the data in between the lines can be reasonably compared to the Ne values deduced from high members of the Balmer series.

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