文献浏览

TABLE OF CONTENTS

Métodos microscópicos para la cuantificación del contenido en fase vítrea de escorias siderúrgicas

Some microscopy methods that can be applied to the quantification of the percentage of vitreous particles of blast furnace slags are reviewed. Details of sample preparation are included and the experimental procedure is briefly described. The main advantages and inconveniences of each method are also considered. All o…

Characterization of Thermo-Elastic Behaviour of Woven Fabric Composites at Elevated Temperatures

Degradation kinetics of polymers in solution: Dynamics of molecular weight distributions

Abstract Polymer degradation occurs when macromolecular chains are broken under the influence of thermal, mechanical or chemical energy. Chain‐end depolymerization and random‐ and midpoint‐chain scission are mechanisms that have been observed in liquid‐phase polymer degradation. Here we develop mathematical models, un…

Congresos, Seminarios y Cursos

The application of the acoustic emission technique to stone decay by sodium sulphate in laboratory tests

Acoustic emission was monitored during salt crystallisation cycles in order to study the mechanisms of rock deterioration by sodium sulphate in laboratory tests. Some porous carbonate stones used in Spanish monuments (Cathedral of Oviedo, Murcia and Seo Vella of Lérida) were selected for this study. The acoustic emiss…

Protective overalls: evaluation of garment design and fit

Protective clothing should ideally provide maximum comfort and protection for the wearer. The design and fit of a garment are factors which can affect both the protective aspects of a garment as well as its comfort. Proper garment fit depends on the relationship of the size of the garment compared with the size of the…

Temperature-induced phase transition of poly(N,N-dimethylaminoethyl methacrylate-co-acrylamide)

Copolymers of N,N-dimethylaminoethyl methacrylate (DMAEMA) and acrylamide (AAm) were prepared to demonstrate a temperature-induced phase transition. Poly DMAEMA has a lower critical solution temperature (LCST) around 50°C in water. With copolymerization of DMAEMA with AAm, the LCST shifts to the lower temperature was…

Achromatic quarter-wave plates using the dispersion of form birefringence

We propose achromatic quarter-wave plates of a subwavelength grating structure. When the period of the grating structure is smaller than the wavelengths of the incident light, the structure is considered to be an optically anisotropic medium. The effective refractive indices strongly depend on the wavelengths, especia…

Effect of Solvent on Titania Particle Formation and Morphology in Thermal Hydrolysis of TiCl 4

Titania powders were synthesized by the thermal hydrolysis of titanium tetrachloride with the yield of above 85% in a mixed solvent of n ‐propanol and water. The morphology of the precipitates was controlled by adjusting the volume ratio of n ‐propanol to water (RH ratio) of the mixed solvent. Precipitates obtained wi…

Development of Oxide Dispersion Strengthened Ferritic Steels for FBR Core Application, (I)

As to an oxide dispersion strengthened (ODs) ferritic steel cladding as the promising candidate for long-life core materials of the fast reactors, previously fabricated claddings had inferior internal creep rupture strength in hoop direction and inferior formability due to less ductility. Those unexpected features of…

Synthesis, Crystal Structure, and Second-Order Optical Nonlinearity of Bis(2-chlorobenzaldehyde thiosemicarbazone)cadmium Halides (CdL2X2; X = Br, I)

The new Schiff base ligand 2-chlorobenzaldehyde thiosemicarbazone (L, 1) has been synthesized and characterized by spectral techniques and single-crystal X-ray analysis. Crystals of 1 are monoclinic, space group P2(1)/n with a = 12.964(4) Å, b = 5.131(5) Å, c = 4.970(1) Å, beta = 94.32(2) degrees, and Z = 4. The thios…

Sintering of Fine Oxide Powders: II, Sintering Mechanisms

Conventional and new sintering mechanisms have been investigated using fine powders of CeO 2 and Y 2 O 3 of excellent sinterability. We have verified the validity of Herrings scaling law for 60%–84% relative density and found that it is consistent with grain‐boundary‐diffusion control. At lower densities, we have foun…

Spectromicroscopy of Poly(ethylene terephthalate): Comparison of Spectra and Radiation Damage Rates in X-ray Absorption and Electron Energy Loss

The C 1s and O 1s X-ray absorption spectra of poly(ethylene terephthalate) (PET) have been recorded using transmission, fluorescence, and electron yield detection. The corresponding electron energy loss spectra (EELS) have been recorded in a scanning transmission electron microscope. These results are compared to the…

Stereochemical Effect of Even−Odd Connecting Links on Supramolecular Assemblies Made of 1-Glucosamide Bolaamphiphiles

Bolaamphiphiles with a 1-glucosamide-head group at each end, N, N‘ -bis(β- d -glucopyranosyl)alkane-1, n -dicarboxamide [ Glc-NC( n )CN-Glc, n = 6, 9, 10, 11, 12, 13, and 14], have been synthesized. Self-assembled supramolecular structures in water strongly depend on whether n is even or odd, which respectively give r…

Crystallization kinetics of suspensions of hard colloidal spheres

The crystallization of suspensions of sterically stabilized polymer particles, with hard-sphere-like interactions, is studied by laser light scattering. Over the range of volume fractions examined, from just below melting to the glass transition, crystallization occurs by homogeneous nucleation. After the suspensions…

Long-range forces and aggregation of colloid particles in a nematic liquid crystal

We calculate the long-range pair potential between spherical colloid particles suspended in a uniform liquid crystal. At weak director anchoring on the particle surface the director distortions decay as \ensuremath{\delta}n\ensuremath{\sim}${\mathrm{r}}^{\mathrm{\ensuremath{-}}3}$sin 2\ensuremath{\theta} away from its…

DNA fibers by electrospinning

Thin fibers of calf thymus Na-DNA were electrospun from aqueous solutions with concentrations from 0.3% to 1.5%. In electrospinning, a high voltage is used to create an electrically charged jet of liquid solution, which dries to leave a polymer fiber. The electrospun DNA fibers have diameters around 50 to 80 nm. The d…

Computer Simulation Studies of Bulk Reduction and Oxygen Migration in CeO2−ZrO2Solid Solutions

Computer simulation techniques have been used to model cubic CeO 2 −ZrO 2 solid solutions in the whole composition range. Aspects related with the oxygen storage capacity of these materials are emphasized. The energetics of the Ce 4+ /Ce 3+ bulk reduction reaction as well as the activation energy for oxygen migration…

Thin film and surface characterization by specular X-ray reflectivity

We review the use of specular X-ray reflectivity (XRR) for the characterization of thin-film and surface structures. Specular X-ray scattering at small scattering vectors allows characterization of electron density profiles perpendicular to the surface on the length scale of 0.1 to 100 nm. This allows measurement of s…