Identification of hydrogen defects inα−Al2O3by first-principles local vibration mode calculations

As structural systems approach their end of service life, integrity assessment and condition monitoring during late life becomes necessary in order to identify damage due to age-related issues such as corrosion and fatigue and hence prevent failure. In this paper, a novel method of level 3 damage identification (i.e. detection, localisation and quantification) from local vibration mode pair (LVMP) frequencies is introduced. Detection is achieved by observation of LVMP frequencies within any of the vibration modes investigated while the location of the damage is predicted based on the ranking order of the LVMP frequency ratios and the damage is quantified in terms of material volume loss from pre-established quantification relations. The proposed method which is baseline-free (in the sense that it does not require vibration-based assessment or modal data from the undamaged state of the pipe) and solely frequency-dependent was found to be more than 90% accurate in detecting, locating and quantifying damage through a numerical verification study. It was also successfully assessed using experimental modal data obtained from laboratory tests performed on an aluminium pipe with artificially inflicted corrosion-like damage underscoring a novel concept in vibration-based damage identification for pipes.

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Local vibration mode mechanism of electron spin–lattice relaxation of PO32-radicals in γ-irradiated (glycine) H3PO3 crystal and in its deuterated analogue

Solid State Communications ◽

10.1016/s0038-1098(01)00498-7 ◽

2002 ◽

Vol 121 (8) ◽

pp. 423-427 ◽

Cited By ~ 15

Author(s):

J. Goslar ◽

S.K. Hoffmann ◽

W. Hilczer

Keyword(s):

Electron Spin ◽

Vibration Mode ◽

Lattice Relaxation ◽

Spin Lattice Relaxation ◽

Local Vibration ◽

Spin Lattice ◽

Deuterated Analogue

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Judd Ofelt Analysis and Optical Properties of Eu\(^{3 + }\) Doped Tellurite Glasses

Communications in Physics ◽

10.15625/0868-3166/24/3s1/5465 ◽

2014 ◽

Vol 24 (3S1) ◽

pp. 136-142 ◽

Cited By ~ 1

Author(s):

Tran Thi Hong ◽

Phan Tien Dung ◽

Vu Xuan Quang

Keyword(s):

Vibration Mode ◽

Transition Probabilities ◽

Emission Cross Section ◽

Stimulated Emission ◽

Radiative Properties ◽

Photoluminescence Spectra ◽

Photoluminescence Properties ◽

Local Vibration ◽

Side Band ◽

Omega 6

In this work, the structural characteristic and photoluminescence properties of Eu\(^{3 + }\) doped B\(_{2}\)O\(_{3}\)-TeO\(_{2}\) -ZnO-Na\(_{2}\)O glasses were investigated. These glasses were prepared by a melting method in air, combined with thermal annealing at 350\(^{\circ}\)C, 450\(^{\circ}\)C and 550\(^{\circ}\)C for different duration times. The structural analysis results of these glasses revealed the formation of micro-crystals in the annealed host glass. The photoluminescence spectra of Eu\(^{3 + }\) doped in these samples were observed. The local vibration mode around Eu\(^{3 + }\) ions was investigated by the phonon side-band (PSB) associated with \(^{7}\!F_{0}-^{5}D_{2}\) transition of Eu\(^{3+}\). Judd-Ofelt parameters were then evaluated based on photoluminescence spectra and the luminescence intensity ratios of \(^{5}D_{0} \to ^{7}\!F_{J}\) (\(J=2, 4\) and 6) to \(^{5}D_{0} \to ^{7}\!F_{1}\) transition were predicted. The obtained results were then used to calculate \(\Omega _{2},\;\Omega _{4},\; \Omega _{6} \) parameters based on Judd-Ofelt theory. These \(\Omega _{2}\), \(\Omega _{4}\), \(\Omega _{6}\) parameters allow to derive radiative properties of Eu\(^{3 + }\) ions in glass material such as transition probabilities, radiative lifetimes and peak stimulated emission cross-section for the \(^{5}D_{0} \to ^{7}\!F_{J}\) transitions.

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First-principles calculation of electronic, vibrational, and thermodynamic properties of triaminoguanidinium nitrate

10.21203/rs.3.rs-218961/v1 ◽

2021 ◽

Author(s):

Wen-Guang Li ◽

Yun-Dan Gan ◽

Zhi-Xin Bai ◽

Ming-Jian Zhang ◽

Fu-Sheng Liu ◽

...

Keyword(s):

Thermodynamic Properties ◽

Thermodynamic Functions ◽

First Principles ◽

Vibration Mode ◽

Energetic Material ◽

State Density ◽

First Principles Calculation ◽

Future Research ◽

Optical Wave ◽

Cell Parameters

Abstract In recent years, the important energetic material triaminoguanidinium nitrate (TAGN) has been widely used, and the process of synthesizing TAGN has become more and more perfect. However, there are relatively few theoretical studies on TAGN. This paper uses first-principles calculations to more systematically study the crystal structure, electronic, vibrational and thermodynamic properties of TAGN. The calculation results show that the calculated unit cell parameters are relatively consistent with the values obtained through X-ray diffraction experiments. This article describes in detail the state density of the valence electron of each atom. By analyzing the vibrational properties of TAGN crystal, the vibration mode corresponding to each optical wave is obtained. At the same time, the vibration mode of each peak in the Raman spectrum and the infrared spectrum is described in detail. Then the calculated value is compared with the experimental value, it can be seen that the error is relatively small. According to the vibration characteristics, a series of thermodynamic functions such as enthalpy (H), Debye temperature (Θ), free energy (F), and entropy (S) are calculated. These thermodynamic functions can provide a certain reference for future research.

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