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91.
R. Caballero C. A. Kaufmann V. Efimova T. Rissom V. Hoffmann H. W. Schock 《Progress in Photovoltaics: Research and Applications》2013,21(1):30-46
In order to transfer the potential for the high efficiencies seen for Cu(In,Ga)Se2 (CIGSe) thin films from co‐evaporation processes to cheaper large‐scale deposition techniques, a more intricate understanding of the CIGSe growth process for high‐quality material is required. Hence, the growth mechanism for chalcopyrite‐type thin films when varying the Cu content during a multi‐stage deposition process is studied. Break‐off experiments help to understand the intermediate growth stages of the thin‐film formation. The film structure and morphology are studied by X‐ray diffraction and scanning electron microscopy. The different phases at the film surface are identified by Raman spectroscopy. Depth‐resolved compositional analysis is carried out via glow discharge optical emission spectrometry. The experimental results imply an affinity of Na for material phases with a Cu‐poor composition, affirming a possible interaction of sodium with Cu vacancies mainly via In(Ga)Cu antisite defects. An efficiency of 12.7% for vacancy compound‐based devices is obtained. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
92.
In this paper we prove a Carlson type inequality for Sugeno integrals. 相似文献
93.
94.
David G Calatayud Teresa Jardiel Marco Peiteado Amador C Caballero Daniel Fernández-Hevia 《Nanoscale research letters》2014,9(1):273
The fabrication of hierarchical anatase microspheres with potential photocatalytic properties eventually comprises a consolidation step in which a high degree of crystalline order is typically achieved through conventional electric heating treatments. This however entails a substantial reduction in the specific surface area and porosity of the powders, with the consequent deterioration in their photocatalytic response. Here, we have tested the employ of microwave heating as an alternative energy-saving sintering method to promote fast crystallization. The results obtained suggest that under the microwave radiation, the TiO2 hierarchical structures can effectively crystallize in a drastically reduced heating time, allowing the specific surface area and the porosity to be kept in the high values required for an improved photocatalytic performance. 相似文献
95.
Anarte Ortiz María Teresa; Caballero Francisco Félix; Ruiz de Adana María Soledad; Rondán Rosa María; Carreira Mónica; Domínguez-López Marta; Machado Alberto; Gonzalo-Marín Montserrat; Tapia María José; Valdés Sergio; González-Romero Stella; Soriguer Federico C. 《Canadian Metallurgical Quarterly》2011,23(2):398
Hypoglycemia is the most common adverse event associated with insulin treatment in diabetes. The consequences of hypoglycemia can be quite aversive and potentially life threatening. The physical sequelae provide ample reason for patients to fear hypoglycemia and avoid episodes. For these reasons, our purpose in this study was to develop a new measure that explores specific fear of hypoglycemia (FH) in adult patients with type 1 diabetes and to examine its psychometric properties. The instrument developed to assess FH was initially made up of 20 items, of which 18 were negative and 2 were positive, assessed on a 5-point Likert scale (1–5). This scale was completed by 229 patients with type 1 diabetes. Additionally, a structured interview and a closed question called subjective fear of hypoglycemia were included as diagnostic criteria. A factor analysis employing the principal-components method and promax rotation was carried out, resulting in a new scale composed of 15 items. Three factors (fear, avoidance, and interference) were obtained and explained 58.27% of the variance. The scale showed good internal consistency (Cronbach's α = .891) and test–retest reliability (r = .908, p 相似文献
96.
97.
C. Isabella Bovolo Simon J. Abele James C. Bathurst David Caballero Marek Ciglan George Eftichidis Branislav Simo 《Computers & Geosciences》2009,35(5):924-945
Within the European Commission-funded MEDIGRID project, Grid computing technology is used to integrate various natural hazard models and data sets, maintained independently at different centres in Europe, into a single system, accessible to users over the internet. Each centre forms a process (application) or data storage node and has been fitted with the Globus toolkit, which provides the distributed computing environment functionality that is required for the system set up. In addition, several Grid data management components were developed to allow the system to operate on different computing platforms. Access to the data and application management services is enabled through a Grid Portal. A series of portlets enable users to access the system, providing a personalised interface to the Grid. Integration of the individual models required them to be modified as web services, so as to be run remotely over the internet. As the models have different data characteristics, a common data format was adopted for creating harmonised data sets and allowing the exchange of data between the models. As an example, the Fire Spread Engine model is used to derive a map of areas that have been burnt by fire. This forms an input to the SHETRAN hydrology, soil erosion and landslide model, which in turn could provide data for other models such as vegetation regeneration. The use of the system is demonstrated for a site in south-west Spain where a large forest fire occurred on 2 August 2003. The MEDIGRID system marks an advance in the integration of independently constructed models to provide improved hazard assessment technology. 相似文献
98.
Eyal Szewkis Miguel Nussbaum Tal Rosen Jose Abalos Fernanda Denardin Daniela Caballero Arturo Tagle Cristian Alcoholado 《International Journal of Computer-Supported Collaborative Learning》2011,6(4):561-575
The purpose of this paper is to show how a large group of students can work collaboratively in a synchronous way within the
classroom using the cheapest possible technological support. Making use of the features of Single Display Groupware and of
Multiple Mice we propose a computer-supported collaborative learning approach for big groups within the classroom. The approach
uses a multiple classification matrix and our application was built for language-learning (in this case Spanish). The basic
collaboration mechanism that the approach is based upon is “silent collaboration,” in which students—through suggestions and
exchanges—must compare their ideas to those of their classmates. An exploratory experimental study was performed along with
a quantitative and qualitative study that analyzed ease of use of the software, described how the conditions for collaborative
learning were achieved, evaluated the achievements in learning under the defined language objectives, and analyzed the impact
of silent and spoken collaboration. Our initial findings are that silent collaboration proved to be an effective mechanism
to achieve learning in large groups in the classroom. 相似文献
99.
100.
Marina Villegas Amador C. Caballero Carlos Moure Pedro Durán José F. Fernández 《Journal of the American Ceramic Society》1999,82(9):2411-2416
High-temperature piezoelectric ceramics based on W6+ -doped Bi4 Ti3 O12 (W-BIT) were prepared by both the conventional mixing oxides and the chemical coprecipitation methods. Sintering was carried out between 800° and 1150°C in air. A rapid densification, >99% of the theoretical density (rhoth ) at 900°C/2 h, took place in the chemically prepared W6+ -doped Bi4 Ti3 O12 ceramics, whereas conventionally prepared BIT-based materials achieved a lower maximum density, ∼94% of rhoth , at higher temperature (1050°C). The microstructure study revealed a platelike morphology in both materials. Platelike grains were larger in the conventionally prepared W-BIT-based materials. The sintering behavior could be related both to the agglomeration state of the calcined powders and to the enlargement of the platelets at high temperature. The W6+ -doped BIT materials showed an electrical conductivity value 2-3 orders of magnitude lower than undoped samples. The electrical conductivity increased exponentially with the aspect ratio of the platelike grains. The addition of excess TiO2 produced a further decrease of the electrical conductivity. 相似文献