Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
The presence of silicon nanocrystals in Er doped SiO2 can enhance the effective Er optical absorption cross section by several orders of magnitude due to a strong coupling between quantum confined excitons and Er. This article studies the fundamental processes that determine the potential of Si nanocrystals as sensiti…
The low-frequency vibrational spectrum of an isolated nanometer-scale solid differs dramatically from that of a bulk crystal, causing the decay of a localized electronic state by phonon emission to be inhibited. We show, however, that an electron can also interact with the rigid translational motion of a nanocrystal.…
The current carrying capacity of ballistic electrons in carbon nanotubes that are coupled to ideal contacts is analyzed. At small applied voltages, electrons are injected only into crossing subbands, the differential conductance is ${4e}^{2}/h.$ At applied voltages larger than $\ensuremath{\Delta}{E}_{\mathrm{NC}}/2e$…
The correlation between ${}^{29}\mathrm{Si}$ chemical shifts and Si-O-Si bond angles in ${\mathrm{SiO}}_{2}$ is determined within density-functional theory for the full range of angles present in vitreous silica. This relation closely reproduces measured shifts of crystalline polymorphs. The knowledge of the correlati…
Unlike semiconducting TiCoSb, ZrCoSb and HfCoSb half-Heusler phases are semimetallic below room temperature and exhibit small Seebeck coefficients of ∼−10 μV/K at 300 K. However, upon substituting (doping) the Co and Sb sites with Pt and Sn, respectively, much larger thermopowers (S) are obtained. For ZrCoSb, S reache…
Iron nitride Fe4N is studied by full-potential LAPW method. Structure parameters, electronic and magnetic properties as well as hyperfine interaction parameters are obtained. We observe perfect agreement with experimental results. Hypothetical Fe4N structure was also calculated to study the influence of disordering ef…
Two electrons confined in quantum dots (QD's) are studied under an assumption of a Gaussian confining potential and its parabolic approximation. We have calculated the energy levels of singlet and triplet states as functions of the range and depth of the confining potential in the two-dimensional (circular) and three-…
The crystal structure of the new fast oxide-ion conductor La 2 Mo 2 O 9 (ionic conductivity of 0.06 S cm - 1 at 800 °C) has been studied. This compound presents a reversible phase transformation around 580 °C from a low-temperature form α-La 2 Mo 2 O 9 to a high-temperature form β-La 2 Mo 2 O 9 . The high-temperature…
In recent years, lack of donor organs has caused many to consider tissue engineering methods as means to replace diseased or damaged organs. This newly-emerging field uses tissue-specific cells in a three-dimensional organization, provided by a scaffolding material, to return functionality of the organ. For these appl…
The efficacy of novel cancer therapeutics has been hampered by the ability to deliver these agents to the tumor at effective concentrations. Liposomes have been used as a method to overcome some delivery issues and, in combination with hyperthermia, have been shown to increase drug delivery to tumors. Particle size ha…
A self-biased dielectric bolometer has been realized by epitaxially grown lead zirconate titanate Pb1.1(Zr0.3Ti0.7)O3 (PZT 30/70) and lanthanum-doped lead zirconate titanate Pb0.83La0.17(Zr0.3Ti0.7)0.9575O3 (PLZT 17/30/70) multilayered thin films using the sol-gel technique. The high-resolution transmission electron m…
FeF (2) films are grown by the reaction of XeF (2) and SeF (6) with iron foil. The growth initially follows the Mott-Cabrera parabolic rate law, indicating that the process is diffusion limited. At a certain film thickness, however, the growth abruptly stops, with the thickness using XeF (2) being nearly double that w…
The photoluminescence (PL) and PL excitation (PLE) properties of Sn-implanted SiO2 layers thermally grown on crystalline Si have been investigated and compared with those from Ge- and Si-implanted SiO2 layers. In detail, the violet PL of Sn-implanted SiO2 layers is approximately two and 20 times higher than those of G…
Several alkenyl diphenyldiacetylene liquid crystals were synthesized and their physical properties evaluated. The introduction of a double bond in the side chain leads to an unexpectedly wide nematic range and an extraordinarily large figure of merit at elevated temperatures. These liquid crystals are particularly att…
The kinetic behavior of quasicrystalline phase formation in amorphous Zr65Al7.5Cu12.5Ni10Ag5 alloys has been studied by using differential scanning calorimetry (DSC), x-ray diffractometry, and transmission electron microscopy. DSC trace obtained during continuous heating from 473 to 873 K shows two distinct exotherms…
Nanoparticles of Eu2O3 and Tb2O3 have been prepared using ultrasound radiation and were deposited sonochemically on microspherical alumina particles. In a different sonochemical reaction Eu2O3 and Tb2O3 were doped into nanophased alumina particles. For both systems the decay times of the fluorescence was measured. The…
We report structural, dielectric, and ferroelectric properties of compositionally graded (Pb,La)TiO3 thin films on LaNiO3/SiO2/Si substrates, where all the films were prepared by the sol-gel technique. The crystalline orientation and surface morphology of the graded films were closely related to the deposition sequenc…
Highly (0001)-oriented YMnO3 thin films on Si(100) substrates were obtained by using a stable precursor solution and rapid thermal annealing at a low temperature of 650 °C in a chemical solution deposition process. Temperature-dependent capacitance–voltage (C–V) and current–voltage (I–V) characteristics were discussed…
Measurements using TGA, SEM, Raman spectroscopy and XRD reveal that diamond oxidizes at around 750 K through oxygen impinging into the densely packed {111} planes throughout the course of the reaction. It is also found that diamond graphitizes under vacuum at about 1100 K without orientation preference, which also occ…
Employing quartz crystal resonators, we have measured the elastic compliance of thin polymers films doped with an azobenzene dye. From a comparison of the shifts of resonance frequency on different acoustic overtones of the resonator, the films’ elastic compliance was derived. Upon irradiation with ultraviolett light…