The shear viscosity of borosilicate glass (BSG) + silica powder compacts was determined during isothermal sintering at temperatures between 665 and 715°C. An optical system was used to measure in situ the densification profiles of the compacts in the form of thick films constrained on a rigid substrate and in-plane stresses generated during sintering. The shear viscosity as a function of relative density was calculated from these measurements by using Scherer's viscous constitutive equations for a porous sintering body. The shear viscosity for samples with silica contents from 0 to 20 vol% generally showed a slow increase with density in the low-density regime followed by a rapid rise after some threshold density that decreased with either increasing silica powder content or decreasing sintering temperature. The dependence of shear viscosity on relative density is consistent with results from sinter-forging experiments. However, results obtained from pure BSG compacts also revealed strong dependence of shear viscosity on temperature and microstructure, which has been all but neglected in previous theoretical studies.

2-[3-(1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidine)-1-propenyl]-1,3,3-trimethyl-3H-indolium idoide (HICI) dye-doped SiO2 particles were synthesized by sol-gel method. Dimension, diameter, distribution, and homogeneity of the particles are closely related to the positively charged dye concentration, corresponding to the zeta potential of the particles. When the dye concentration reaches about 7.8 × 10−4 mol/mol SiO2, corresponding to the isoelectric point of the particles, the maximum particle size and the most homogeneity can be reached.

Glasses in the NiO–TiO2 system in the composition range 15 to 25 mol% of NiO have been synthesized by the sol-gel technique by heat treatment of the precursor sol at 500°C. The glass structure is built up by crosslinking of two units, namely TiO6 octahedron and NiO3 triangle. Glassy structure is confirmed at a microscopic level by scanning electron microscopy. An increase in the values of peak-to-peak width of electron paramagnetic resonance with increasing concentration of Ni2+ is attributed to an enhanced interaction between neighboring paramagnetic Ni2+ ions.

Highly photostable CdS nanoparticles modified with an alkyl group were prepared by an improved microemulsion technique using hexanethiol as cosurfactant. The surface-modified CdS nanoparticles catalyzed the photo-oxidation of 4-chlorophenol via continuously bubbling oxygen under uv light. The photocatalytic oxidation activity of the CdS nanoparticles was enhanced due to the formation of their compact CdS cores with strong chemical surface modification by heat treatment.

A series of gallium-lanthanum-sulfide (GLS) glasses of different oxide concentration has been made and their spectroscopic properties, thermal properties, and the crystallization behavior of the glasses have been studied. It was revealed that the formability of GLS glasses relies on the existence of a certain amount of oxide content. The thermal stability of GLS glasses changes as a function of oxide concentration. The results have also shown that increasing oxide content caused a shift of the visible absorption edge to shorter wavelengths and an increase of absorption intensity in the infrared region at the multiphonon edge. Two closely related crystalline phases have been identified in the crystallized GLS glasses. For the first time it has been revealed that thermally stable GLS glasses can be made near the eutectic point of these two crystal phases by introducing an optimized amount of oxide.

Stable and homogeneous alkoxide precursor solutions of lithium ethoxyethoxide and manganese ethoxyethoxide in 2-ethoxyethanol were synthesized by ligand exchange reaction of lithium isopropoxide and manganese 2-ethoxide, respectively, with 2-ethoxyethanol. [Li–Mn–O] precursor solution was prepared by mixing these modified alkoxide precursor solutions. LiMn2O4 powders were successfully synthesized by pyrolysis of the [Li–Mn–O] precursor powder in O2 temperature as low as 200 °C. The nanocrystalline LiMn2O4 powders 20–50 mm in diameter after heat treatment up to 700 °C consisted of the ordered (111) plane and performed with good cyclability as the cathode materials for Li secondary batteries.

Ba6–3xNd8+2xTi18O54 (BNT) is a useful dielectric resonator at microwave frequencies. Recent work has shown that the major secondary phase in this system can be indexed as Nd4Ti9O24 (JCPDS 33–943). The present study has evealed that when half of the stoichiometric Ba+2 is replaced with Ca+2 or Sr+2, a third, tilted perovskite-structured phase, NdTiO3, is also present. It forms as coherent intragranular regions within BNT grains and always contains some of the divalent dopant species. The orientational relationship between NdTiO3 and BNT has been established.

Europium-doped yttrium oxide (Y2O3:Eu) thermographic phosphor films were deposited on Ni-alloy substrates using a novel and cost-effective electrostatic-assisted chemical vapor deposition (EACVD) technique. The thermoluminescence properties were studied under irradiation by an ultraviolet laser. It was found that crystallized Y2O3: Eu films could be deposited at a temperature as low as 550 °C. Annealing of the as-deposited films at higher temperatures (>1000 °C) improved the luminescence properties due to further crystallization processes. The correlation of the lifetime decay and temperature change of the films showed that the EACVD-deposited films are suitable for use in phosphor thermometry for high-temperature applications.

The third-order nonlinear optical susceptibilities, χ(3), of the xLi(Na and K)2O · (100 − x)TeO2 binary glasses have been measured by the third harmonic generation (THG) method. It is found that the χ(3) of each series of glasses decreases with increasing alkali oxide content. The largest χ(3) values obtained are about 1.3 × 10−12 esu for a 7.5Li2O · 92.5TeO2 glass, being about 45 times larger than that of fused silica glass for the present series samples. For the purpose of investigating the relationship between the χ(3) and the optical parameters, such as linear refractive index, polarizability per unit volume which is represented by the term (nω2 – 1)/(nω2 + 2), dispersion energy (Ed) which is related to the Abbé number, and excitation energy (E0) which is closely related to the optical band gap (Eg), we derived the equations that relate the χ(3) to optical parameters on the basis of Lines’ model. Finally, it was experimentally confirmed that the χ(3) value of alkali oxide-TeO2 glasses is proportional to the term (nω2 + 2)3 (nω2 – 1) · Ed/E02

Aluminum-tantalum bilayers have been investigated for their potential to serve as conductive barriers to oxygen diffusion when annealed at conditions corresponding to crystallization of perovskite dielectrics such as lead lanthanum titanate (PLT). Ta (50 nm)/Al (15 nm) structures have been deposited on Si substrates and annealed in oxygen at 650 and 700 °C for various amounts of time. The as-deposited and annealed structures have been characterized by x-ray diffraction (XRD), Rutherford backscattering spectroscopy (RBS), and Auger electron spectroscopy (AES) analysis and by four-point probe electrical measurements. It has been found that the Al–Ta structures can withstand complete oxidation when exposed to oxygen at 650 °C for 30 min or 700 °C for 1 min and the oxide layer formed at the surface of the structure acts as a barrier to further oxygen diffusion. When a PLT film was deposited directly on the Al–Ta structures intermixing took place. It was therefore necessary to insert a Pt layer between the Al–Ta barrier and PLT layer. In such a case the PLT showed electrical properties similar to those obtained when deposited on SiO2/Pt; however, the Al–Ta structure did interact with Pt during the perovskite formation anneal. It has been found that this interaction can be prevented by preannealing the Al–Ta, in oxygen, prior to the deposition of Pt.

Fe K-edge x-ray absorption fine-structure (XAFS) measurements were performed on glass samples of (Fe3O4)0.3(P2O5)0.7 with various amounts of Na2O or UO2. Near-edge and extended XAFS regions are studied and comparisons are made to several reference compounds. We find that iron in the base glass is ∼25% divalent and that the Fe2+ coordination is predominantly octahedral, while Fe3+ sites are roughly split between tetrahedral and octahedral coordinations. Also, we measure roughly one Fe–O–P link per iron. Substitution of Na2O or UO2 up to 15 mol% primarily affects the first Fe–O shell. The results are compared to data from the related material Fe3(P2O7)2.

The effects of an electric field on phase separation in CBP (CaOB2O3P2O5) have been studied. It was discovered that an electric field can inhibit the process of phase separation in CBP glasses. If the electric field strength is increased, the inhibiting effect will increase, too. The mechanism of phase separation in an electric field has been discussed in light of the ir spectrum of CBP glasses.

Unsupported films and thin rods were prepared by the sol-gel method from solutions of triethoxysilane and methyldiethoxysilane. Measurements of elastic modulus, density, glass transition temperature, and refractive index were performed at different aging times. Results showed a large increase of the elastic modulus with aging time, which was related to the progressive condensation taking place in the xerogel network, as shown by solid-state nuclear magnetic resonance (NMR). The stiffness increase was shown to correspond to higher glass transition temperature and larger density and refractive index. Different increasing rates of the physical and mechanical characteristics were observed for films and rods during aging. This behavior was related to the different loss rate of the pore liquid, which affects the network evolution in the wet gel.

An electrochemical method used to obtain aluminum(III)-8 hydroxyquinoline (Alq3) blended into poly(N-vinylcarbazole) (PVK) matrix is described. The PVK-Alq3 blends show an intense green photoluminescence whose intensity increases by adding a small percentage of a substituted coumarin to the PVK-Alq3 solution. The material can easily be spin-coated to obtain homogeneous luminescent thin films suitable for optoelectronic applications. Spectrophotometry in the uv-vis-ir range, photoluminescence, and lifetime measurements are used to characterize the PVK-Alq3 films.

In this paper, we report atomic force microscopy (AFM) images of a tubular polymer and its supermolecular polymer thin films, operated in contact mode at room temperature in air. The configuration models are also calculated using molecular dynamics. The diameter of the polymer nanotube is about 0.7 nm, the smallest size a tube can have. The results of calculation agree with the experimental results.

Epitaxial films of TiC1-x (0.15 < x < 0.50) were deposited on MgO(001) and 6H–SiC(0001) at 250 and 400 °C by coevaporation of C60 and Ti. Films deposited on MgO(001) were single-crystalline down to deposition temperatures of at least 250 °C as determined by x-`ray diffraction (XRD), low energy electron diffraction (LEED), and transmission electron microscopy (TEM). Films deposited on 6H–SiC(0001) were also epitaxial at 250 °C, but TEM showed a columnar microstructure due to the occurrence of twinned domains in the [111] growth direction normal to the substrate.

The effects of heat-treatment temperature on LiNbO3 thin films prepared by the polymeric precursor method were investigated. The precursor solution was deposited on Si(111) substrates by dip coating. X-ray diffraction and thermal analyses revealed that the crystallization process occurred at a low temperature (420 °C) and led to films with no preferential orientation. High-temperature treatments promoted formation of the LiNb3O8 phase. Scanning electron microscopy, coupled with energy dispersive spectroscopy analyses, showed that the treatment temperature also affected the film microstructure. The surface texture—homogeneous, smooth, and pore-free at low temperature—turned into an “islandlike” microstructure for high-temperature treatments.

TaSiN films deposited as layered TaN–SiN structures of various compositions have been examined for their oxidation resistant properties during annealing in oxygen at annealing conditions commonly used to prepare perovskite dielectrics. The films have been characterized by Rutherford backscattering analysis (RBS), x-ray diffraction (XRD), and electrical resistivity measurements. Films with less than 15 at.% Si showed some resistance to oxidation after annealing for 1 min at 650 °C but became fully oxidized after longer anneals. Increasing the Si content up to 28 at.% increasingly improved the oxidation resistance of the alloys to the point where the films resisted complete oxidation for up to 5 min at 700 °C. For alloys with greater than 28 at.% Si, no oxidation could be detected by RBS or electrical measurements for anneals up to 5 min at 700 °C. Furthermore, these high Si content alloys were still conductive with resistivities of near 1000 μΩ cm. It was also found that TaSiN and lead lanthanum titanate (PLT) interact strongly during annealing, and another nonoxidizing barrier metal, such as Pt, is required between the two materials if TaSiN is to be used as an electrode/barrier with lead-based perovskites.

Bulk amorphous alloys of PdxNiyFe80−x−yP20 (25 ≤ x ≤ 60, 20 ≤ y ≤ 55, x + y ≥ 60) were prepared by a flux-melting and water-quenching method. Seven-mm diameter glassy rods of Pd40Ni40−xFexP20 (0 ≤ x ≤ 20) were studied in greater detail. For these alloys, the difference between the crystallization and glass transition temperatures ranges from 102 K for x = 0 to 53 K for x = 20. In this composition range, the reduced glass transition temperature, Trg, ranges from 0.66 to 0.57. The change in density upon crystallization ranges from 0.24 ± 0.04% for x = 0 to 1.33 ± 0.24% for x = 10. The partial molar volume of Fe in amorphous Pd40Ni40−xFexP20 alloys is significantly larger than the molar volume of (metastable) fcc Fe. This, as well as a comparison with the molar volumes of crystalline compounds, suggests chemically selective Fe–Pd bonding in these glasses.

The optical properties of heat-treated polyparaphenylene (PPP) were investigated by means of Raman and photoluminescence (PL) spectroscopy. Special attention is given to PPP heat-treated to temperatures (THT) near the carbonizing temperature region (THT ≈ 700°C) since polymer-based carbonaceous compounds with low-THT (<1000 °C) have been found to exhibit electrochemical properties that strongly contrast both the as-prepared polymer and fully carbonized samples. The Raman spectra show that for THT in the range 650–725°C, several Raman bands near 1300 cm−1 can be correlated with both ground-state benzenoid and excited-state quinoid PPP Ag modes. An increase in quinoid character is observed with increasing THT, which is consistent with the theoretically predicted stabilization of the quinoid form in the presence of a high density of defects. The smaller energy bandgap for π – π* transitions in the quinoid conformation relative to that for the benzenoid form allows for a resonance condition to be present for laser excitation wavelengths (λexc) near the visible (∼1–2 eV). We also report a small dispersion effect in the observed quinoid breathing mode band which can be compared to dispersion effects previously reported for the case of trans-PA. The decrease in bandgap for the defect-induced quinoid form is also evidenced in the PL spectra of samples heat-treated up to 650°C, which show vibronic structure in the blue-green emission data in the energy range 2.4–3.0 eV, with well-resolved peaks separated by quinoid phonon energies of 0.165 eV. Franck–Condon analysis shows an increase in the Huang–Rhys parameter (S) with increasing THT which can be related to changes in the electron-phonon coupling of valence and conduction band states.