Three-dimensional measurements with a novel technique combination of confocal and focus variation with a simultaneous scan

The most common optical measurement technologies used today for the three dimensional measurement of technical surfaces are Coherence Scanning Interferometry (CSI), Imaging Confocal Microscopy (IC), and Focus Variation (FV). Each one has its benefits and its drawbacks. FV will be the ideal technology for the measurement of those regions where the slopes are high and where the surface is very rough, while CSI and IC will provide better results for smoother and flatter surface regions. In this work we investigated the benefits and drawbacks of combining Interferometry, Confocal and focus variation to get better measurement of technical surfaces. We investigated a way of using Microdisplay Scanning type of Confocal Microscope to acquire on a simultaneous scan confocal and focus Variation information to reconstruct a three dimensional measurement. Several methods are presented to fuse the optical sectioning properties of both techniques as well as the topographical information. This work shows the benefit of this combination technique on several industrial samples where neither confocal nor focus variation is able to provide optimal results.Postprint (author's final draft

Structural changes at grain boundaries in bcc iron induced by atomic collisions

Symmetrical tilt and twist grain boundary structures have been simulated in bcc iron using a many-body potential of the Finnis-Sinclair form. Initial structures were relaxed to the local minimum energy configuration using molecular dynamics. The width and relative energies of the resulting grain boundaries have been calculated. Collision cascades have been initiated in the structure by imparting initial energy to a single Fe atom and the interaction of the cascade with the grain boundary has been studied again using molecular dynamics simulations. The cascades were chosen where the primary knock-on atom (PKA) had initial energy of 1 keV and the orientation and distance of the PKA were changed in order to generate some statistical information concerning the radiation damage near the interface. The results show an increased radiation damage in the grain boundary region compared to the bulk material. The interstitials that form in the boundary region seem to be stable and do not move away from the boundary during the recrystallisation phase of the collision cascade. Clusters of interstitials are easily produced at the boundary in either structure but the defects induced near the twist boundary are more extensive than those near the tilt boundary

Constructing topological models by symmetrization: A PEPS study

Symmetrization of topologically ordered wavefunctions is a powerful method for constructing new topological models. Here, we study wavefunctions obtained by symmetrizing quantum double models of a group $G$ in the Projected Entangled Pair States (PEPS) formalism. We show that symmetrization naturally gives rise to a larger symmetry group $\tilde G$ which is always non-abelian. We prove that by symmetrizing on sufficiently large blocks, one can always construct wavefunctions in the same phase as the double model of $\tilde G$. In order to understand the effect of symmetrization on smaller patches, we carry out numerical studies for the toric code model, where we find strong evidence that symmetrizing on individual spins gives rise to a critical model which is at the phase transitions of two inequivalent toric codes, obtained by anyon condensation from the double model of $\tilde G$.Comment: 10 pages. v2: accepted versio

Exact Matrix Product States for Quantum Hall Wave Functions

We show that the model wave functions used to describe the fractional quantum Hall effect have exact representations as matrix product states (MPS). These MPS can be implemented numerically in the orbital basis of both finite and infinite cylinders, which provides an efficient way of calculating arbitrary observables. We extend this approach to the charged excitations and numerically compute their Berry phases. Finally, we present an algorithm for numerically computing the real-space entanglement spectrum starting from an arbitrary orbital basis MPS, which allows us to study the scaling properties of the real-space entanglement spectra on infinite cylinders. The real-space entanglement spectrum obeys a scaling form dictated by the edge conformal field theory, allowing us to accurately extract the two entanglement velocities of the Moore-Read state. In contrast, the orbital space spectrum is observed to scale according to a complex set of power laws that rule out a similar collapse.Comment: 10 pages and Appendix, v3 published versio

Analysis of the factors that produce lack of motivation in english class in first year students in the Institute Miguel Bonilla Obando in Villa Austria in Managua during the second semester of 2010.

The lack of motivation is a big problem that is affecting the students from first year of secondary in Miguel Bonilla Obando Institute. Through this research it is sought to focus in one of the main problem that is affecting the education system in our country and especially in the school that it is being researched.Besides that, it was prepared an interview for the teacher, a focal group for students and an interview for parents in order to find the factors that are affecting the English language learning in students from Miguel Bonilla Obando Institute. Through this research it has been found many factors that influence negatively in students motivation. Factors such as: Economical, emotional and educative

Analysis of the factors that provoke lack of motivation in english class in seventh grade students of the Institute Modesto Armijo Lozano in unidad de proposito Neighborhood in Managua during the first semester of 2011

In Nicaragua the English language has a great impact in the educative process because the higher demand of English speakers in the labor market. The English language is known as a universal language because it is spoken around the world used in business, studies and it opens doors to opportunities, in which the individual can achieve the success as a professional. It is necessary to mention that the teachers are in charge to form future professionals for our society. The lack of motivation is a big problem that is affecting the students from first year of high school in Modesto Armijo Lozano Institute and it is necessary to find the factors that influence in the student’s motivation. Through this research it is sought to focus in one of the main problem that is affecting the education system in our country and especially in our school that it is being researched. Besides that, it was prepared an interview for the teacher, a focal group for students and a survey for parents in order to find the factors that are affecting the English language learning in students from Modesto Armijo Lozano Institute. Therefore, we aim for students of Modesto Armijo Institute to quit fearing whenever they study English for the first time. We have to provide them with our support and interest in the goals they propose to study and learn English. This research intends to find out many factors that influence positive and negatively student’s motivation. In fact we need information that could help to give solution to the problem we face with the students