Restrepo, Sebastian Echeverri
8页查看更多>>摘要：The presence of substitutional atoms, other than iron (Fe), in the cementite (Fe3C) phase in steels can have a beneficial influence on different mechanical and thermodynamic properties. For example, the addition of molybdenum (Mo), which tends to partition to cementite and stabilise it, can improve the hardness of the steel at higher temperatures. In order to better understand the effects of Mo as a substitutional element, an energetic, structural, electronic, and mechanical characterisation of cementite containing Mo atoms was performed. Formation enthalpies, densities of states, and the full stiffness tensors where calculated and analysed in terms of preferential occupation sites, stability, ductile/brittle behaviour, and isotropic and directional evolution of the elastic constants.
原文链接:
NSTL
Elsevier
Bouarroudj, T.Bezzi, H.Mekki, D. E.Tairi, L....
7页查看更多>>摘要：A surfactant-free hydrothermal technique was used to synthesize calcium (Ca2+) incorporated ZnS nanoparticles (ZnS:Ca). The structural, morphological, optical and microstructural properties of the produced nanoparticles are investigated by XRD, SEM, PL and XRF techniques, respectively. The XRD patterns revealed the preservation of the cubic phase after Ca2+ addition, and a decrease of the crystallite size. The SEM micrographs showed the formation of good shaped spherical particles, and evenly distributed. The ZnS:Ca photoluminescence emission bands were blue-shifted and broader than those of pristine ZnS. Finally, the photocatalytic activity of methylene orange (MO) was enhanced by Ca2+ incorporation. According to XRF measurements, the solubility limit of Ca2+ in ZnS lattice is found to be at 0.16% of Ca2+/Zn2+ mass ratio. This result can explain the saturation of the rate constant in the photocatalysis process.
原文链接:- NSTL
- Elsevier
El Radaf, I. M.Al-Zahrani, H. Y. S.
8页查看更多>>摘要：In this research work, thin films of BiSbS3 have been successfully synthesized onto well-cleaned soda-lima glass substrates via the chemical bath deposition procedure. The X-ray diffraction patterns of the chemically deposited BiSbS3 films depicted that the synthesized films exposed polycrystalline nature with orthorhombic structure. The analyses of the linear optical parameters of the chemically deposited BiSbS3 thin films refer to improving the values of the absorption coefficient, alpha and the linear refractive index, n via the increase in the film thickness. In addition, there is an observed reduction in the energy gap, E-g values from 1.38 to 1.22 eV occurred by raising the film thickness. Furthermore, there is an enhancement in the nonlinear optical constants and the optoelectrical parameters occurred by raising the film thickness where the nonlinear refractive index, n(2), the optical free carrier concentration, N-opt and the optical conductivity sigma(opt) were enlarged with increasing the film thickness.
原文链接:- NSTL
- Elsevier
Sharma, Punit KumarPandey, O. P.
13页查看更多>>摘要：In the present work different CeO2 heterostructures are synthesized with (Zn0.003-xCdx)S-0.003 via co-precipitation method by varying the concentration of zinc (Zn) and cadmium (Cd). The synthesized heterostructures were characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy, Photoluminescence (PL) and Raman spectroscopy. XRD results confirmed the formation of NPs with average crystallite size of 3-5 nm. TEM micrographs depicted the formation of agglomerated non-symmetrical NPs. EDS spectra gives confirmation for the presence of all the elements in synthesized material. FTIR, PL and Raman spectroscopy confirmed the presence of ZnS and CdS in synthesized heterostructures with CeO2 NPs. The photocatalytic activity has been studied by the UV-visible spectrophotometer. The crystal violet (CV) dye was used to check the photocatalytic activity of the synthesized heterostructures. It has been observed that the heterostructures of CeO2 with (Cd0.0015Zn0.0015)S-0.003 has shown enhanced catalytic activity and large rate constant than all other synthesized samples.
原文链接:- NSTL
- Elsevier
Lopez-Pena, GabrielHamraoui, KhouloudHorchani-Naifer, KarimaGerke, Christoph...
7页查看更多>>摘要：The development of selective and controlled photo-thermal therapies requires luminescent nanoparticles capable of simultaneous heating and contactless thermal sensing. Until now, thermal therapies have suffered from a lack of control over the absolute temperature of the treated tissue because the nanothermometers used for thermal feedback, based on a spectral analysis of emitted radiation, were affected by the inhomogeneous extinction of the tissues. This work shows how this deficiency can be overcome by using core-shell-shell nanostructures doped with lanthanide ions (Nd3+ and Yb3+). Thermal reading was achieved from the analysis of the Yb3+ luminescence lifetime whereas simultaneous heating was achieved thanks to the non-radiative deexcitations of Nd3+ ions. Simple proof-of-concept experiments show the great potential of these lanthanide-doped nanostructures for the development of in vivo photo-thermal treatments with absolute and reliable thermal feedback.
原文链接:- NSTL
- Elsevier
Satyam, Jagdish KumarSaini, Sapan Mohan
9页查看更多>>摘要：The structural, electronic and thermoelectric properties of narrow gap ErMSb (M = Ni, Pd) half Heusler (HH) compounds are determined using first-principle calculations, based on density functional theory combined with Boltzmann transport theory. We employed Coulomb corrected generalized gradient approximation (GGA + U) which is the most competent method to treat rare earth compounds. We found spin up/down Ni/Pd-d and spin down Er-f states are mainly contributing to the total density of states (DOS) near Fermi energy (E-F). Both the investigated compounds exhibit the indirect narrow energy gaps similar to 0.25 eV that are in agreement with the corresponding experimental values. We obtained fairly high values of the Seebeck coefficient (S) in agreement with available experimental data. The calculated value of total S, using two current model, is 141 mu V/K and 159 mu V/K at 300 K in ErNiSb and ErPdSb HH compounds, respectively. We also find the monotonically increasing value of ZT and reaches 0.76 at 800 K in ErNiSb compounds, whereas 0.51 is the maximum ZT for the ErPdSb compound at 300 K. We obtained favorable and stable ZT values (ZT > 0.7) for a wide temperature range in ErNiSb compound in agreement with the experiment. It suggests ErNiSb as a promising candidate for thermoelectric applications.
原文链接:- NSTL
- Elsevier
Miranda Jr, E. J. P.Dos Santos, J. M. C.
7页查看更多>>摘要：The unit cell wave attenuation of elastic Bloch waves in 1-3 piezoelectric phononic structures with BaTiO3 inclusions in a polymeric matrix is reported. This attenuation can be observed by the evanescent Bloch waves in the complex dispersion diagram of the periodic piezoelectric ceramic structure. Full and complete Bragg-type band gaps are observed. The piezoelectricity of the periodic lead-free ceramic inclusions improves the band gap width and wave attenuation in a specific frequency spectrum. These characteristics can be used for the wave attenuation design using smart periodic structures, for surface acoustic wave (SAW) filter and 1-3 piezocomposite transducer design using piezoelectric phononic structures with BaTiO3 inclusions.
原文链接:- NSTL
- Elsevier
Fatima, KaneezAin, QuratulMohammed, LawalJamil, Muhammad...
9页查看更多>>摘要：Zintl compounds have gained exceptional interest in optoelectronic and thermoelectric applications. The present work includes the detailed study of electronic, optical and thermal response of Zintl phase MgA(l2)X(2) (X = C, Sb) under the umbrella of density functional theory (DFT). Generalized gradient approximation (GGA) and modified Becke-Johnson (mBJ) potentials are used to determine the exchange-correlation potential. The structures are optimized and the stability is achieved with formation energy. An indirect bandgap of 2.74eV is observed in MgAl2C2 with mBJ potential whereas MgAl2Sb2 shows a metallic nature. The optical response of both compounds is calculated which confirms the potential of MgAl2C2 in future optoelectronic devices. The material's thermoelectric response is also evaluated using the BoltzTrap code. The figure of merit (ZT) value is achieved up to 0.83 in the case of MgAl2C2 which indicates that it exhibits strong thermoelectric behavior and it is a promising candidate for applications in renewable energy devices.
原文链接:- NSTL
- Elsevier
