The character of optical excitations in nanoscale and atomic-scale materials is often strongly mixed, having contributions from both single-particle transitions and collective, plasmon-like response. This complicates the quantum description of these excitations, because there is no clear way to define their quantization. To move toward a quantum theory for these optical excitations, they must first be characterized so that single-particle-like and collective, plasmon-like excitations can be identified. We show that time-dependent density functional theory can be used to make that characterization if both the charge densities induced by the excitation and the transitions that make up the excitation are analyzed. Density functional theory predicts that single-particle-like and collective excitations can coexist. Exact calculations for small nanosystems predict that single-particle excitations evolve into collective excitations as the electron–electron interaction is turned on with no indication that they coexist. These different predictions present a challenge that must be resolved to develop an understanding for quantum excitations in nanoplasmonic materials.

Semi-interpenetrating polymer network (semi-IPN) and fully interpenetrating polymer network (full-IPN) hydrogels composed of sodium alginate (SA) and N-isopropylacrylamide (NIPAAm) were prepared with Ca2+ and N,N′-methylenebisacrylamide (BIS) as the cross-linkers, respectively. The influence of the SA content and crosslinking degree of alginate on thermosensitive, swelling, mechanical, morphological, and thermal properties was investigated in detail. The hydrogels obtained exhibited obvious thermosensitivity and rapid swelling rate. The presence of Ca2+ contributed to the improvement of mechanical properties obviously, without altering the thermosensitivity and network porosity of the hydrogels significantly. The compressive strength of full-IPN hydrogel was improved considerably, while the tensile strength was increased by 308.5% than semi-IPN hydrogel. The Tg of full-IPN dried hydrogel ran up to 142.9 °C with respect to 97.3 °C of pure PNIPAAm, and the improvement indicated that hydrogel with more compact structure was prepared.

Multifunctionalized nanoparticles have a great attention owing to their unique advantages as ideal tools for gene/drug delivery, bioimaging, labeling, or intracellular tracking in biomedical applications. In the present work, azole functional Poly(glycidyl methacrylate) (PGMA) grafted hollow silica sphere (HSS) nanoparticles synthesized and characterized as biomaterials. For the preparation of HSS particles, a two-step method based on the sol–gel process was used in this study. HSS grafted with PGMA by free radical polymerization of (glycidyl methacrylate) (GMA) and HSPGMA (PGMA grafted HSS) modified with 5-aminotetrazole (ATet), 3-amino-1,2,4-triazole (ATri), and 1H-1,2,4-triazole (Tri) to obtain 1,2,4-triazole functional PGMA grafted HSS (HSPGMA-Tri), 5-aminotetrazole functional PGMA grafted HSS (HSPGMA-Tet) and 5-Amino-Triazole functional PGMA grafted HSS (HSPGMA-ATri) molecules via ring opening of the epoxide ring. Azole functional PGMA grafted HSS composites were doped with phosphoric acid. Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) analyses were confirmed the grafting and modification of HSS. TGA and DSC were used to examine the thermal stability and homogeneity of the materials.

In this work, the correlation between the number of nonbridging oxygen (NBO) atoms and the thermal and optical properties of TeO2–Li2O–MoO3 glasses was studied. Samples containing (100 − x)TeO2–x(Li2O–MoO3) with x = 10, 15, 20, and 25 mol% were investigated by Raman and Fourier transform infrared (FTIR) spectroscopies. From the optical absorption measurements, the band gap energies were determined. The Raman and FTIR results showed that with increasing x, the TeO4 units transform into TeO3+1 units and then into TeO3 units, while the Mo coordination changes from 4 → 6. This transformation corresponds to a decrease in the total number of NBO with increasing x in this glass matrix. The decrease in the NBO is also confirmed by the increase in band gap energies and the decrease in the optical basicity, indicating a more polymerized network with increasing x.

The initial microscale mechanisms and materials interfacial process responsible for hydration of calcium silicates are poorly understood even in model systems. The lack of a measured microscale chemical signature has confounded understanding of growth mechanisms and kinetics for microreaction volumes. Here, we use Raman and optical spectroscopies to quantify hydration and environmental carbonation of tricalcium silicates across length and time scales. We show via spatially resolved chemical analysis that carbonate formation during the initial byproduct in microscale reaction volumes is significant, even for subambient CO2 levels. We propose that the competition between carbonation and hydration is enhanced strongly in microscale reaction volumes by increased surface-to-volume ratio relative to macroscale volumes, and by increased concentration of dissolved Ca2+ ions under poor hydration conditions that promote evaporation. This in situ analysis provides the first direct correlation between microscale interfacial hydration and carbonation environments and chemically defined reaction products in cementitious materials.

A series of zeolite–zeolite composites were prepared by a two-step hydrothermal crystallization procedure in which the mixture of presynthesized ZSM-5 zeolite acts as nutrients for the growth of postsynthesized Y zeolite, and the as-synthesized products are denoted as MFI–FAU. The structural, crystalline, and textural properties of the as-synthesized materials, as well as the references Y, ZSM-5, and a corresponding physical mixture composed of Y and ZSM-5 zeolite, were characterized by x-ray powder diffraction (XRD), Fourier transform infrared spectrum (FTIR), temperature-programmed desorption of ammonia, N2 adsorption–desorption, scanning electron microscopy, energy-dispersive spectrometry, and Thermogravimetry. The results show that the ratio of Y to ZSM-5 in the composite can be adjusted by controlling the hydrothermal treatment time of the second-step synthesis. Steric hindrance provoked by the concurrently growing crystals offers the postsynthesized Y zeolite phase, a relatively smaller size. A hierarchical pores system, which results from the extraction of silicon species from ZSM-5 and the polycrystalline accumulation of Y zeolite, has been created in the zeolite–zeolite composite. Catalytic performances of the zeolite–zeolite composite catalysts as well as the references catalysts were investigated during the catalytic cracking of isopropylbenzene. As compared with the corresponding physical mixture, the composite catalysts display the excellent catalytic performances with a higher conversion of isopropylbenzene as well as a longer catalytic life because of the introduced hierarchical pores system and the formation of special composite structure.

The effect of Dy-doping on the dielectric nonlinearity was investigated in Mn and V-doped BaTiO3 multilayer ceramic capacitors under the same grain size condition, which was described by the Preisach model utilizing the first order reversal curve (FORC) distribution. The dielectric constants in both low and high field region could be enhanced by the Dy-doping, and it was associated with the increase of both reversible and irreversible FORC distributions near zero bias, whereas there was little variation in the saturation polarization that scales to the magnitude of spontaneous polarization. These results demonstrate that both reversible and irreversible domain wall motions are enhanced by Dy-donor incorporation in BaTiO3 resulting in softening of the dielectrics and increase of dielectric constants, which is supposed to be caused by the decrease of the pinning sources such as defect dipoles formed by the oxygen vacancies and their interaction with the domain walls.

Gd2TixZr2−xO7 (x = 0 to 2) pyrochlore was irradiated by 30 MeV C60 clusters, which provide an extremely high ionizing energy density. High-resolution transmission electron microscopy revealed a complex ion-track structure in Gd2Ti2O7 and Gd2TiZrO7, consisting of an amorphous core and a shell of a disordered, defect-fluorite structure. As compared with the irradiation by 1.5 GeV U ions with the highest energy loss, the track structure is consistent with tracks created by monoatomic swift heavy ions, but the diameters (with the entire diameter of 17 nm for Gd2Ti2O7 and 15 nm for Gd2TiZrO7) are significantly larger due to the much smaller velocity and higher energy density of the C60 ions. Ion tracks created by monoatomic ions are challenging to describe by HRTEM, as the boundary between disordered fluorite and pyrochlore matrix is less distinct. However, the C60 irradiation shows a clearly resolved ion track with completely crystalline, disordered, defect-fluorite structure around an amorphous core. Based on the distinct boundaries of the track morphology, inelastic thermal-spike calculations were used to describe the track size and extract critical energy densities for the interpretation of the complex core–shell morphologies for the different pyrochlore compositions.

Lead-free ceramics (1 − x)(K1/2Na1/2)NbO3–xBi(Sc3/4Co1/4)O3 [(1 − x)KNN–xBSC] were prepared by the conventional solid-state sintering method. X-ray diffraction patterns show that the introduction of BSC into KNN system caused insignificant change in crystal structure. The composition with x = 0.015 has diphasic tetragonal and orthorhombic phases. Moreover, the grain size significantly dependent on the composition. The phase transition temperatures of orthorhombic–tetragonal (TO–T) and tetragonal–cubic (TC) decreased with increasing x from 0 to 0.025. The TO–T value of KNN–0.015BSC ceramic is close to room temperature, resulting in good electrical properties (d33 = 190 pC/N, kp = 40.3%, εr = 1494, tgδ = 0.026), with the Curie temperature TC = 321 °C. The combination of good piezoelectric properties and high TC makes these KNN–BSC ceramics suitable for elevated temperature piezoelectric devices.

The development of high performance Al–Cu based alloys generally depends on the strict control of the Fe content. However, with the increasing use of recycled aluminum alloys, it is necessary to increase the tolerance for the Fe content in Al–Cu cast alloys for the purpose of low cost, energy saving, and environment protection. In this study, the formation of Fe-rich intermetallics and their effect on the tensile properties of squeeze-cast Al–5.0 wt% Cu–0.6 wt% Mn alloys with an Fe content of up to 1.5 wt% have been investigated. The full formation sequence of squeeze-cast Al–5.0 wt% Cu–0.6 wt% Mn alloys with different Fe contents has been established. The results were also compared with the corresponding results obtained for Al–5.0Cu–0.6Mn alloys prepared by gravity die casting. It is found that the Fe-rich intermetallic compounds mainly consist of α-Fe and β-Fe in alloys with a low Fe content, changing into Al6(FeMn) and Al3(FeMn) for alloys with a high Fe content. The applied pressure promotes the formation of the Fe-rich intermetallics α-Fe/Al6(FeMn) and prevents the precipitation of needle-like β-Fe/Al3(FeMn). The elongation of the alloys gradually decreases with the Fe content, and a maximum value for both the ultimate mechanical strength and the yield strength was found for the alloys with 0.5 wt% Fe. The tensile properties of alloys with a different Fe content significantly increased as the applied pressure was increased from 0 to 75 MPa, especially the elongation.

A crystal plasticity finite element constitutive model combined with Bassani and Wu hardening law has been developed to investigate the effects of grain/phase boundary (GB/PB) on mechanical properties and microtexture evolution of Cu bicrystals and Cu–Al bicrystals during nanoindentation process. The simulated load–displacement curve for the Cu single crystal with Goss initial orientation has been analyzed and compared with the result from the experiment to validate the parameters. The numerical results indicate that the effects of GB/PB on load–displacement curves, indentation Young's moduli, Mises stresses, pile-up patterns are insignificant for Cu bicrystals while they are significant for Cu–Al bicrystals. The main reason is that PB works as a very effective barrier to resist the plastic slip propagation of the deformed material. The effects from different misorientations of GBs/PBs are insignificant for both Cu bicrystals and Cu–Al bicrystals. The effects of GB/PB on lattice rotation angles for both Cu bicrystals and Cu–Al bicrystals are significant.

The effect of current direction (CD) on the microstructural evolution and mechanical properties of a Cu–Zn binary phase (α + β) alloy during the primary process of phase transformation induced by electric current pulses (ECP) treatment was investigated. To clarify the effect of CD, the samples were prepared with different angles between the CD and rolling direction (RD) from 0° to 90°. Results showed that not only the microstructural evolution but also the corresponding mechanical properties all had a saddle point in the sample with the angle 45°. Analyzed from the mechanical properties, it could be found that the anisotropic of the materials becomes stronger due to the application of ECP. An important finding is that by changing the angles between the CD and the RD, a novel and effective approach to control the phase transformation process could be provided.

In this study, the mechanism of ferrite grain refinement during warm compression deformation in the (γ + α) region of Cu–P–Cr–Ni–Mo weathering steel was analyzed by optical microscopy and electron backscatter diffraction. Results showed that fine equiaxed ferrite grains surrounded by high-angle boundaries (HABs) formed along the initial boundaries as the strain is increased. As the deformation temperature decreased, some low-angle boundaries shifted to HABs in intragranular ferrite, and ferrite grain refinement was promoted by continuous dynamic recrystallization. Microstructural observations also indicated that the fine ferrite grains of approximately 1.4–3 μm in size can be obtained by deformation at 750 °C with a strain over 0.69 because of ferrite dynamic recrystallization. Moreover, both strain and deformation temperature influenced the ferrite grain size and volume fraction. Thus, the predominant mechanism for ferrite grain refinement in the (γ + α) region was continuous dynamic recrystallization.