Search results for "Focus"
showing 10 items of 1181 documents
Critical current modulation induced by an electric field in superconducting tungsten-carbon nanowires
2021
The critical current of a superconducting nanostructure can be suppressed by applying an electric field in its vicinity. This phenomenon is investigated throughout the fabrication and electrical characterization of superconducting tungsten-carbon (W-C) nanostructures grown by Ga+ focused ion beam induced deposition (FIBID). In a 45 nm-wide, 2.7 μm-long W-C nanowire, an increasing side-gate voltage is found to progressively reduce the critical current of the device, down to a full suppression of the superconducting state below its critical temperature. This modulation is accounted for by the squeezing of the superconducting current by the electric field within a theoretical model based on th…
Dificultades para Codificar, Relacionar y Categorizar Problemas Verbales Algebraicos: dos estudios con estudiantes de secundaria y profesores en form…
2014
En resolución de problemas verbales por transferencia, la activación de problemas ya conocidos que sirvan de guía, depende de las analogías percibidas entre éstos y el problema a resolver. Se desarrollan dos estudios relacionados para analizar en qué características se basan los estudiantes para codificar problemas y detectar sus analogías, en tareas de categorización (sorting). Se utilizaron técnicas cuantitativas y cualitativas combinadas. Primero se analizó cómo los estudiantes de secundaria son influidos por diferentes variables características de problemas de ciencias. Una gran proporción de sujetos no fue capaz de percibir las analogías y diferencias adecuadas entre problemas. El segu…
Geometric contacts of surfaces immersed in Rn, n⩾5
2009
Abstract We study the extrinsic geometry of surfaces immersed in R n , n ⩾ 5 , by analyzing their contacts with different standard geometrical models, such as hyperplanes and hyperspheres. We investigate the relation between different types of contact and the properties of the curvature ellipses at each point. In particular, we focalize our attention on the hyperspheres having contacts of corank two with the surface. This leads in a natural way to the concept of umbilical focus and umbilic curvature.
Automorphisms of $mathbb{A}^{1}$-fibered affine surfaces
2011
We develop technics of birational geometry to study automorphisms of affine surfaces admitting many distinct rational fibrations, with a particular focus on the interactions between automorphisms and these fibrations. In particular, we associate to each surface S of this type a graph encoding equivalence classes of rational fibrations from which it is possible to decide for instance if the automorphism group of S is generated by automorphisms preserving these fibrations.
Surface Studies with Slow Positron Beaks
1984
Slow-positron physics is an exciting and rapidly advancing field. The continuing progress in the development of intense monochromatic beams of low-energy positrons has made it possible to perform a number of landmark experiments, where the interaction of the positron with solid surfaces plays a central role. These experiments either deal with fundamental atomic physics (positronium spectroscopy) or focus on the electronic and atomic properties of the surface region, using positrons as a probe. In the former category, the surface is involved just as an efficient source of positronium-like atoms. On the other hand, in the second category of experiments the surface i s the main object of study…
Hybrid chalcogenide nanoparticles: 2D-WS2 nanocrystals inside nested WS2 fullerenes.
2013
The MOCVD assisted formation of nested WS2 inorganic fullerenes (IF-WS2) was performed by enhancing surface diffusion with iodine, and fullerene growth was monitored by taking TEM snapshots of intermediate products. The internal structure of the core–shell nanoparticles was studied using scanning electron microscopy (SEM) after cross-cutting with a focused ion beam (FIB). Lamellar reaction intermediates were found occluded in the fullerene particles. In contrast to carbon fullerenes, layered metal chalcogenides prefer the formation of planar, plate-like structures where the dangling bonds at the edges are stabilized by excess S atoms. The effects of the reaction and annealing temperatures o…
SUSTAINABLE LOCAL DEVELOPMENT FROM PERSPECTIVE OF CITIZENS: SALASPILS MUNICIPALITY (LATVIA) CASE
2015
Conditions are very different in the different parts of any country, and the quality of life as well as the impacts produced on the environment depend on a variety of local factors of environmental, economic and cultural nature, and every action must cope with such local conditions, traditions, and attitudes. Thereby one of the approaches on assessment of sustainable development could be based on subjective evaluation of citizens of certain municipality. During 2010-2012 in Salaspils municipality (Latvia) the SPIRAL methodology for measurement of subjective well-being indicators using co-responsibility approach was approbated, which was the basis for establishing the more efficient dialogue…
Localising SDGs in Rural Uganda: Learning Active Citizenship Through the Saemaul Undong Model
2021
The Sustainable Development Goals (SDGs) are premised on the principles of ‘leaving no one behind’ and transformative development. Achieving the goals requires active citizens that are engaged in community development and claiming their rights. The chapter explores the ways in which a local NGO uses Saemaul Undong (SMU), a Korean community development model, to localise holistic achievement of a number of SDGs. Drawing on theories of the travel of global ideas in institutional sociology and based on participatory research including in-depth interviews, focus group discussions and participation in community activities, the chapter analyses how SMU’s three pillars of self-help, diligence and …
MR-guided focused ultrasound application for moving target tumor ablation in abdominal area: Coil selection
2020
PubMed: 32276552
Postgraduate Students’ Experience of Using a Learning Management System to Support Their Learning: A Qualitative Descriptive Study
2021
Introduction Educational institutions worldwide have implemented learning management systems (LMSs) to centralise and manage learning resources, educational services, learning activities and institutional information. LMS has mainly been used by teachers as storage and transfer of course material. To effectively utilise digital technologies in education, there is a need for more knowledge of student experiences with digital technology, such as LMSs and especially regarding how LMSs can contribute to student engagement and learning. Objective This study aimed to gain knowledge about postgraduate nursing students’ experiences with the use of LMS in a subject in an advanced practice nursing ma…