Search results for "microscopi"
showing 10 items of 232 documents
The microscopic theory of diffusion-controlled defect aggregation
1998
Abstract The kinetics of diffusion-controlled aggregation of primary Frenkel defects ( F and H centers) in irradiated CaF 2 crystals is theoretically studied. Microscopic theory is based on the discrete-lattice formalism for the single defect densities (concentrations) and the coupled joint densities of similar and dissimilar defects treated in terms of the Kirkwood superposition approximation. Conditions and dynamics of the efficient F center aggregation during crystal heating after irradiation are analyzed.
A consistent microscopic theory of collective motion in the framework of an ATDHF approach
1978
Based on merely two assumptions, namely the existence of a collective Hamiltonian and that the collective motion evolves along Slater determinants, we first derive a set of adiabatic time-dependent Hartree-Fock equations (ATDHF) which determine the collective path, the mass and the potential, second give a unique procedure for quantizing the resulting classical collective Hamiltonian, and third explain how to use the collective wavefunctions, which are eigenstates of the quantized Hamiltonian.
Acceleration radiation and the Planck scale
2008
A uniformly accelerating observer perceives the Minkowski vacuum state as a thermal bath of radiation. We point out that this field-theory effect can be derived, for any dimension higher than two, without actually invoking very high energy physics. This supports the view that this phenomenon is robust against Planck-scale physics and, therefore, should be compatible with any underlying microscopic theory.
Keyhole Limpet Hemocyanin: Molecular Structure of a Potent Marine Immunoactivator
2000
Objectives: In this short review we present a survey of the available biochemical and electron microscopic data on keyhole limpet hemocyanin (KLH). Results: The b
Nanomateriales basados en lantánidos: caracterización y visualización
2022
Las nanopartículas upconversion (UCNP) comenzaron a desarrollarse a inicios del presente siglo, generando una gran expectación e interés por sus propiedades fotofísicas particulares. Las UCNP son nanomateriales capaces de producir el fenómeno upconversion (UC) mediante el cual fotones de baja energía (de la región del infrarrojo cercano, NIR) se transforman en fotones de alta energía (en la región del UV-vis). Los principales actores del fenómeno son los iones lantánidos que se encuentran como dopantes de una matriz nanométrica transparente. Por tanto, en las UCNP, a diferencia de las nanopartículas (NP) semiconductoras, el confinamiento nanométrico no es el responsable de las propiedades ó…
Microscopic theory of colloid formation in solids under irradiation
1996
Results of the first-principles study of diffusion-controlled aggregation of Frenkel defects-interstitial atoms-under irradiation of solids are presented. Conditions of the efficient radiation-induced aggregation of vacancies and interstitials are studied and the scenario of this process is presented.
Collagen ultrastructure in ruptured cruciate ligaments
1992
The ultrastructure of collagen fibrils was investigated in normal (n 39) and ruptured (n 23) human anterior cruciate ligaments. The normal ligament had a complex three-dimensional structure. Collagen fibrils predominantly had a unidirectional course with parallel arrangement and a mean diameter of 75 (20-185) nm. Four days after anterior cruciate ligament rupture, the mean fibril diameter was increased; it later decreased, probably due to synthesis of young, thin 30-40 nm fibrils. Interfibrillar dysplastic collagen fibrils were detected in the extracellular matrix of ruptured ligaments. They were more frequently found later than 3 days after rupture and were seen also at a distance of 2-3 c…
Mechanical and Thermal Stability of Adhesive Membranes with Nonzero Bending Rigidity
2010
Membranes at a microscopic scale are affected by thermal fluctuations and self-adhesion due to van der Waals forces. Methods to prepare membranes of even molecular scale, e.g., graphene, have recently been developed, and the question of their mechanical and thermal stability is of crucial importance. To this end we modeled microscopic membranes with an attractive interaction and applied Langevin dynamics. Their behavior was also analyzed under external loading. Even though these membranes folded during isotropic compression as a result of energy minimization, the process at high confinement was similar to crumpling of macroscopic nonadhesive sheets. The main difference appeared when the com…
Characterization and processability of molecular-based nanoparticles and 2D crystals by scanning probe microscopy
2014
El desarrollo de nuevos dispositivos multifuncionales se basa en la posibilidad de miniaturización de sus componentes así como de su ensamblado de una manera controlada. Conocer el tamaño, la forma y las propiedades de estos nanocomponentes así como poder integrarlos y combinarlos a voluntad son factores cruciales a la hora de diseñar dispositivos inteligentes que integren estas nanoestructuras con macro(nano) electrodos. El reto que se plantea tiene pues dos vertientes: por un lado la caracterización y manipulación de nuevos materiales en la nanoescala, y por otro, su organización en superficies y/o su ensamblado para crear materiales multifuncionales heteroestructurados. En esta tesis se …
Anatomie microscopique de l'involution des troncs branchiaux des amphibiens
1938
Izvilkums no: Archives d'anatomie, d'histologie et d'embryologie normales et expérimentales, t. xxv, 1938, p. 1-64.