Topic
Debye model
About: Debye model is a research topic. Over the lifetime, 7462 publications have been published within this topic receiving 133987 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: In this article, the elastic and thermal properties of single-phase ternary and quaternary Al-Ti-V-Cr-Nb-Mo refractory high-entropy alloys based on the first-principles calculations are studied.
50 citations
TL;DR: The study demonstrates the power of the model for simulating THz reflection imaging; however, for biological tissues extra Debye terms or a more detailed theory may be required to link THz image contrast to physiological composition and structural changes of breast tissue associated with differences between normal and tumour tissues.
Abstract: The aim of this work was to evaluate the capabilities of Debye theory combined with Finite Difference Time Domain (FDTD) methods to simulate the terahertz (THz) response of breast tissues Being able to accurately model breast tissues in the THz regime would facilitate the understanding of image contrast parameters used in THz imaging of breast cancer As a test case, the model was first validated using liquid water and simulated reflection pulses were compared to experimental measured pulses with very good agreement (p = 100) The responses of normal and cancerous breast tissues were simulated with Debye properties and the correlation with measured data was still high for tumour (p = 098) and less so for normal breast (p = 082) Sections of the time domain pulses showed clear differences that were also evident in the comparison of pulse parameter values These deviations may arise from the presence of adipose and other inhomogeneities in the breast tissue that are not accounted for when using the Debye model In conclusion, the study demonstrates the power of the model for simulating THz reflection imaging; however, for biological tissues extra Debye terms or a more detailed theory may be required to link THz image contrast to physiological composition and structural changes of breast tissue associated with differences between normal and tumour tissues
50 citations
TL;DR: In this paper, the elastic constants and their derived properties of various cubic Heusler compounds were calculated using the first-principles density functional theory, and the results showed that many properties of these compounds correlate to the mass or nuclear charge Z of the main group element.
Abstract: Elastic constants and their derived properties of various cubic Heusler compounds were calculated using the first-principles density functional theory. To begin with, Cu 2MnAl is used as a case study to explain the interpretation of the basic quantities and compare them with experiments. The main part of the work focuses on Co 2-based compounds that are Co 2Mn M with the main group elements M = Al, Ga, In, Si, Ge, Sn, Pb, Sb, Bi, and Co 2 T M with the main group elements Al or Si, and the 3 d transition metals T = Sc, Ti, V, Cr, Mn, and Fe. It is found that many properties of Heusler compounds correlate to the mass or nuclear charge Z of the main group element. Additional representation and compact simplification of the elastic data is useful to investigate and compare their influence on crystal stability and physical properties. Here, Blackman’s and Every’s diagrams are used to compare the elastic properties of the materials, whereas Pugh’s and Poisson’s ratios are used to analyze the relationship between interatomic bonding and physical properties. It is found that Pugh’s criterion on brittleness needs to be revised whereas Christensen’s criterion describes the ductile–brittle transition of Heusler compounds very well. The calculated elastic properties give hint on a metallic bonding with an intermediate brittleness for the studied Heusler compounds. The universal anisotropy of the stable compounds has values in the range of 0.57 < A U < 2.73. The compounds with higher A U values are found close to the middle of the transition metal series. In particular, Co 2ScAl with A U = 0.01 is predicted to be an isotropic material that comes closest to an ideal Cauchy solid as compared to the remaining Co 2-based compounds. Apart from the elastic constants and moduli, the sound velocities, Debye temperatures, and hardness are predicted and discussed for the studied systems. The calculated slowness surfaces for sound waves reflect the degree of anisotropy of the compounds.
50 citations
TL;DR: In this article, the specific heat of four samples of the 81 K-superconductor Yba 2 Cu 4 O 8 prepared under high oxygen pressure was investigated, and a tentative separation of the total specific heat into electron and phonon terms was obtained by a least-squares fit of high-temperature data using a model of the phonon density of states.
Abstract: The specific heat of four samples of the 81 K-superconductor Yba 2 Cu 4 O 8 prepared under high oxygen pressure is investigated. The low-temperature specific heat is sample-dependent. For the most homogeneous sample, the coefficient of the linear term at T ⪡ T c is γ ∗ =4.9±0.2mJ/(K 2 mole) and the initial Debye temperature is θ (0)=350±10K. A small specific heat jump Δ C / T c =12 to 16 mJ/(K 2 mole) is observed at the superconducting transition; it is only weakly correlated with the field cooling Meissner fraction (14 to 55% in 20 Oe). A tentative separation of the total specific heat into electron and phonon terms is obtained by a least-squares fit of high-temperature data using a model of the phonon density of states. The electron contribution is found to be much smaller than for YBa 2 CU 3 O 7 . Thermochemical data are tabulated.
50 citations
TL;DR: In this article, the structural, elastic and mechanical properties of the intermetallic compound MgRh with a CsCl-type structure were determined from a linear fit of the calculated stress-strain function according to Hooke's law.
50 citations