Influence Of Ti Related Centers On ZnSe Radiation Spectra

1997 ◽  
Vol 487 ◽  
Author(s):  
L.I. Bruk ◽  
V. A. Korotkov ◽  
P. I. Ketrush ◽  
A. V. Simashkevich ◽  
K. D. Sushkevich ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Homogeneous Field ◽  
Volume Distribution ◽  
Acceptor Center ◽  
Radiation Spectra ◽  
Edge Radiation ◽  
Blue Radiation ◽  
Exciton Region ◽  
Ti Addition ◽  
Good Agreement

AbstractZnSe annealed in (Zn + 46 wt.% TI) vapors and in Zn melt with 5 wt.% TI addition was investigated. The radiation spectra in the regimes of stationary and pulsed photoluminescence (PL) with the time delaying at 77K were studied. By using coloured cathodoluminescence (CCL) combined with the crystal cleavage image in the secondary electrons reflection the impurities and defects volume distribution was evaluated. It was revealed that at the annealing of ZnSe crystals in TI vapors, the cleavage surface has light blue radiation on the red background with an homogeneous field distribution with the dimensions ˜ 1..10μm. On the edge of the cleavage on the depth of 10μm the region of yellow radiation is observed. At the annealing in the melt the irradiation became blue on a weak red background, the homogeneity enhances. At the room temperature PL spectra correspond with images of cleavage in CCL. In the PL (at 77K) spectra in the exciton region there were observed: bands at 445nm (blue radiation); edge radiation at 460nm, 485nm with the LO phonons replica (blue region) and in the impurity region: bands 500...570nm (yellow-green radiation); 600...700nm and 720...800nm (red radiation). The investigation of PL of the annealed samples surface allowed the suppose, that the bands at 2,76eV (450nm), are stipulated by the free-bound transition on the acceptor center (E + 40meV), including TI.The comparison of ion and tetrahedronical covalent radiuses of Zn, Se and TI, electronegativity, probability of Zni and Vse. formation at the annealing allowed to suppose that, TI fills Vse. and forms (Zni Tls) and (Vse. Tlse) complexes. The carried out theoretical calculations according to the model of two-atom molecule gives the energy of complexes occurrence (Ev + 0,04) eV and (Ev + 0,8) eV. The first value accordingly is in good agreement with the experimental data.

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 Etude par résonance magnétique nucléaire de composés organiques contenant des chalcogènes. II. L'éther de diphényle et ses analogues soufré, sélénié et telluré

1979 ◽  
Vol 57 (22) ◽  
pp. 2967-2970 ◽  
Author(s):  
Gabriel Llabrès ◽  
Marcel Baiwir ◽  
Léon Christiaens ◽  
Jean-Louis Piette
Keyword(s):  
Crystal Structure ◽  
Theoretical Calculations ◽  
Heavy Atom ◽  
Mesomeric Effect ◽  
Heavy Atom Effect ◽  
Inductive Effects ◽  
Structure Determinations ◽  
Résonance Magnétique ◽  
Atom Effect ◽  
Good Agreement

The 1Hmr study of the title compounds has revealed a screw conformation, with defined interconversion processes, in good agreement with crystal structure determinations and theoretical calculations. The mesomeric effect of the heteroatom is smaller than in the anisole series, due to steric inhibitions.The 13Cmr enhances, to some extent, these conclusions. In the case of Te compounds, a heavy atom effect adds to the classical mesomeric and inductive effects to account for the experimental observations.

Turbulent dispersion in a non-homogeneous field

1999 ◽  
Vol 392 ◽  
pp. 45-71 ◽  
Author(s):  
ILIAS ILIOPOULOS ◽  
THOMAS J. HANRATTY
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Stochastic Model ◽  
Point Source ◽  
Time Scales ◽  
Langevin Equation ◽  
Turbulent Dispersion ◽  
Homogeneous Field ◽  
Fully Developed Flow ◽  
Good Agreement

Dispersion of fluid particles in non-homogeneous turbulence was studied for fully developed flow in a channel. A point source at a distance of 40 wall units from the wall is considered. Data obtained by carrying out experiments in a direct numerical simulation (DNS) are used to test a stochastic model which utilized a modified Langevin equation. All of the parameters, with the exception of the time scales, are obtained from Eulerian statistics. Good agreement is obtained by making simple assumptions about the spatial variation of the time scales.

The continuous absorption of light in alkali-metal vapours

1953 ◽  
Vol 219 (1136) ◽  
pp. 89-101 ◽  
Keyword(s):  
Cross Section ◽  
Alkali Metals ◽  
Theoretical Calculations ◽  
Wave Length ◽  
Energy Difference ◽  
Continuous Absorption ◽  
Absorption Of Light ◽  
Sodium Vapour ◽  
Good Agreement ◽  
Dipole Length

The first section of this paper is an account of some experiments on the absorption of light in sodium vapour from the series limit at 2412 Å to about 1600 Å (an energy difference of 2·6 eV). The absorption cross-section at the limit is 11·6 ± 1·2 x 10 -20 cm 2 . The cross-section decreases giving a minimum of 1·3 ± 0·6 x 10 -20 cm 2 at 1900 Å and then increases to 1600 Å. A theoretical calculation by Seaton based on the dipole-length formula gives good agreement with the experiments at the series limit and also correctly predicts the wave-length for the minimum, but it predicts a significantly lower absorption at the minimum. The experiments described in the first section of the paper conclude a series on the absorption of light in the alkali metals. The second section consists of a general discussion of the results of these experiments and of their relation to theoretical calculations. There is good agreement between theory and experiment except in regard to the magnitude of the absorption at the minimum.

Edge radiation spectra of luminescent ceramic A2B6

1986 ◽  
Vol 45 (3) ◽  
pp. 953-957
Author(s):  
A. I. Proskura ◽  
I. V. Zakharchenko
Keyword(s):  
Radiation Spectra ◽  
Edge Radiation

scholarly journals Influence of Frequency on the Resolution of Magnetostrictive Bio-Inspired Whisker Sensors

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Ran Zhao ◽  
Bo-wen Wang ◽  
Quan-guo Lu ◽  
Jian-wu Yan ◽  
Xiao-cui Yuan
Keyword(s):  
Vibration Frequency ◽  
Dynamic Testing ◽  
Theoretical Calculations ◽  
Beam Theory ◽  
Experimental System ◽  
Flow Sensors ◽  
Maximum Resolution ◽  
Sensing Model ◽  
Euler Bernoulli Beam ◽  
Good Agreement

Magnetostrictive biomimetic whiskers have been used as tactile and flow sensors. Compared to other types of whiskers, such whiskers have the advantage of being able to perform static and dynamic measurements. For dynamic measurement, the whisker’s resolution changes with varying vibration frequency; however, the mechanism for this influence has not been studied yet. Thus, the aim of this study is to investigate the resolution–frequency correlation. First, the structure and operation principle of the whisker were analyzed. Then, the Euler–Bernoulli beam theory was employed to establish the sensing model of the magnetostrictive whisker. Finally, the mapping relationship between sensor resolution and frequency was obtained. The eigenfrequency analysis was implemented by FEM to obtain the frequency response of the whisker. A vibration experimental system was built for dynamic testing. The experimental results were in good agreement with the theoretical calculations. Furthermore, it was noted that the resolution was positively correlated with frequency, and the maximum resolution was attained at the natural frequency (two peak values appeared at the first-order and second-order eigenfrequencies). Our research reveals the manner in which a whisker sensor’s resolution is affected by the vibration frequency. The theoretical model can be used to predict the resolution of magnetostrictive whisker sensors.

scholarly journals A Deformation Dipole Model for Crystals: Application to NaCI

1983 ◽  
Vol 36 (6) ◽  
pp. 897 ◽  
Author(s):  
DD Richardson ◽  
J Mahanty
Keyword(s):  
Lattice Dynamics ◽  
Theoretical Calculations ◽  
Ion Pairs ◽  
Dipole Model ◽  
Model Based ◽  
Good Agreement

We present a deformation dipole model based on theoretical calculations of induced moments in ion pairs. The model is generally applicable and in this paper is applied to the calculation of the lattice dynamics of NaCI. Only a few parameters are required to give good agreement with experiment. Limitations of the approach are discussed.

TEMPERATURE EFFECT ON THERMOMECHANICAL PROPERTIES OF BERYLLIUM CHALCOGENIDES BeS, BeSe AND BeTe

2006 ◽  
Vol 20 (01) ◽  
pp. 49-61 ◽  
Author(s):  
F. BENKABOU
Keyword(s):  
Elastic Constants ◽  
Dynamic Properties ◽  
Theoretical Calculations ◽  
Thermomechanical Properties ◽  
Structural Dynamic ◽  
Experimental Values ◽  
Beryllium Chalcogenides ◽  
Increasing Temperature ◽  
And Diffusion ◽  
Good Agreement

We have used the molecular-dynamic method for the calculation of the structural, dynamic and elastic properties of group BeS , BeSe and BeTe compounds for temperature ranging from 300 to 1200 K. Tersoff potential has been used to model the interaction between the groups II–VI compound atoms. The structural properties of cubic BeS , BeSe and BeTe have been calculated, and good agreement between the calculated and experimental values have been found. We have also predicted the elastic constants and diffusion coefficients of BeS , BeSe and BeTe . The values found compare very well with the theoretical results. For the temperature range under study, all elastic constants and dynamic properties show a softening with increasing temperature very similar to the theoretical calculations.

scholarly journals Synthesis, characterization and theoretical calculations of Cu(I) complex of trithiocyanuric acid [Cu(ttc)3]

2018 ◽  
Vol 23 (2) ◽  
pp. 241-266 ◽  
Author(s):  
Ximena Verónica Jaramillo-Fierro ◽  
César Zambrano ◽  
Francisco Fernández ◽  
Regino Saenz-Puche ◽  
César Costa ◽  
...  
Keyword(s):  
Computational Study ◽  
Theoretical Calculations ◽  
Photophysical Properties ◽  
Vibrational Frequencies ◽  
Basis Sets ◽  
Vertical Excitation ◽  
Experimental Values ◽  
Homo Lumo ◽  
Perchlorate Hexahydrate ◽  
Good Agreement

A new Cu(I) complex constructed by reaction of trithiocyanuric acid (ttc) and copper (II) perchlorate hexahydrate has been successfully synthesized by a slow sedimentation method in a DMF solvent at room temperature. The molecular structure of the compound was elucidated by MALDI-TOFMS, UV Vis and FTIR spectroscopy, DSC-TGA analysis and magnetic susceptibility measurement. The proposed structure was corroborated by a computational study carried out with the Gaussian09 and AIMAII programs using the RB3LYP hybrid DFT functional with both 6-31G and Alhrich-TZV basis sets. The calculated vibrational frequencies values were compared with experimental FTIR values. Photophysical properties of the synthesized complex were evaluated by UV-Visible spectroscopy and compared with computed vertical excitation obtained from TDDFT. The theoretical vibrational frequencies and the UV Vis spectra are in good agreement with the experimental values. Additionally, the Frontier Molecular Orbitals (HOMO-LUMO) and the Molecular Electrostatic Potential of the complex was calculated using same theoretical approximation. The results showed the interaction between three coordinatedl igand atoms and the Cu(I) ion.

Calculationof Equilibrium Isotope Effects in a Conformationally Mobile Carbocation

1989 ◽  
Vol 44 (5) ◽  
pp. 480-484 ◽  
Author(s):  
Martin Saunders ◽  
Gary W. Cline ◽  
Max Wolfsberg
Keyword(s):  
Theoretical Calculations ◽  
Isotope Effects ◽  
Stable Solution ◽  
Constant Matrix ◽  
Force Constant Matrix ◽  
Hydride Shift ◽  
Rapid Equilibrium ◽  
Theory And Experiment ◽  
Good Agreement ◽  
C Nmr

The rapid, degenerate 1,2-hydride shift in 2,3-dimethyl-2-butyl cation in stable solution in SbF5/SO2C1F was perturbed by deuterium and 13C leading to splittings observed by 13C NMR spectroscopy over a range of temperatures. Accurate values for equilibrium isotope effects were obtained from these data. Theoretical calculations of the equilibrium isotope effects were performed using the Gaussian-86 program to obtain an optimized geometry and the Cartesian force constant matrix, followed by the program QUIVER which applies the Bigeleisen-Mayer method. When all of the conformers, which are in rapid equilibrium, were considered specifically, quite good agreement between theory and experiment was obtained.

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