New Step (new + step)

Distribution by Scientific Domains

Selected Abstracts

Efficient Hybrid Solar Cells from Zinc Oxide Nanoparticles and a Conjugated Polymer,


ZnO nanoparticles dispersed in a semiconducting polymer form the active layer of a solar cell (see Figure) that is able to convert up to 40,% of the incident photons at 500,nm into electrical current and has a power conversion efficiency of about 1.5,% in sunlight. Manufactured at low temperature using environmentally friendly materials, it represents a new step to ,green electricity'. [source]

Diplomats Without a Flag: The Institutionalization of the Delegations of the Commission in African, Caribbean and Pacific Countries,

This article deals with the evolution of the status and role of the delegations of the European Commission in Africa from the 1960s onwards. Starting from an institutionalist approach, it tries to show to what extent this evolution reflects the bureaucratization of the external service (in the Weberian sense of a rational and professional civil service) in parallel with that of the administration of the Commission as a whole. It envisages the current reform of the external service as a new step in the construction of a mature European bureaucracy. [source]

Large-area epitaxial silicon solar cells based on industrial screen-printing processes

Filip Duerinckx
Abstract Thin-film epitaxial silicon solar cells are an attractive future alternative for bulk silicon solar cells incorporating many of the process advantages of the latter, but on a potentially cheap substrate. Several challenges have to be tackled before this potential can be successfully exploited on a large scale. This paper describes the points of interest and how IMEC aims to solve them. It presents a new step forward towards our final objective: the development of an industrial cell process based on screen-printing for >,15% efficient epitaxial silicon solar cells on a low-cost substrate. Included in the discussion are the substrates onto which the epitaxial deposition is done and how work is progressing in several research institutes and universities on the topic of a high-throughput epitaxial reactor. The industrial screen-printing process sequence developed at IMEC for these epitaxial silicon solar cells is presented, with emphasis on plasma texturing and improvement of the quality of the epitaxial layer. Efficiencies between 12 and 13% are presented for large-area (98,cm2) epitaxial layers on highly doped UMG-Si, off-spec and reclaim material. Finally, the need for an internal reflection scheme is explained. A realistically achievable internal reflection at the epi/substrate interface of 70% will result in a calculated increase of 3,mA/cm2 in short-circuit current. An interfacial stack of porous silicon layers (Bragg reflectors) is chosen as a promising candidate and the challenges facing its incorporation between the epitaxial layer and the substrate are presented. Experimental work on this topic is reported and concentrates on the extraction of the internal reflection at the epi/substrate interface from reflectance measurements. Initial results show an internal reflectance between 30 and 60% with a four-layer porous silicon stack. Resistance measurements for majority carrier flow through these porous silicon stacks are also included and show that no resistance increase is measurable for stacks up to four layers. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Pressure Prediction for High-Temperature and High-Pressure Formation and Its Application to Drilling in the Northern South China Sea

WANG Zhenfeng
Abstract, There are plentiful potential hydrocarbon resources in the Yinggehai and Qiongdongnan basins in the northern South China Sea. However, the special petrol-geological condition with high formation temperature and pressure greatly blocked hydrocarbon exploration. The conventional means of drills, including methods in the prediction and monitoring of underground strata pressure, can no longer meet the requirements in this area. The China National Offshore Oil Corporation has allocated one well with a designed depth of 3200 m and pressure coefficient of 2.3 in the Yinggehai Basin (called test well in the paper) in order to find gas reservoirs in middle-deep section in the Miocene Huangliu and Meishan formations at the depth below 3000 m. Therefore, combined with the "863" national high-tech project, the authors analyzed the distribution of overpressure in the Yinggehai and Qiongdongnan basins, and set up a series of key technologies and methods to predict and monitor formation pressure, and then apply the results to pressure prediction of the test well. Because of the exact pressure prediction before and during drilling, associated procedure design of casing and their allocation in test well has been ensured to be more rational. This well is successfully drilled to the depth of 3485 m (nearly 300 m deeper than the designed depth) under the formation pressure about 2.3 SG (EMW), which indicate that a new step in the technology of drilling in higher temperature and pressure has been reached in the China National Offshore Oil Corporation. [source]

Searching for Culture,High and Low

Jennifer Kayahara
This article examines the link between finding out about cultural activities on the Web and finding out through other people. Using data from interviews with Torontonians, we show that people first obtain cultural information from interpersonal ties or other offline sources and only then turn to the Web to amplify this information. The decisions about what information to seek from which media can be evaluated in terms of a uses and gratifications approach; the main gratifications identified include efficiency and the availability of up-to-date information. Our findings also have implications for the model of the traditional two-step flow of communication. We suggest the existence of new steps, whereby people receive recommendations from their interpersonal ties, gather information about these recommendations online, take this information back to their ties, and go back to the Web to check the new information that their ties have provided them. [source]

Quality of performance of everyday activities in children with spina bifida: a population-based study

M Peny-Dahlstrand
Abstract Aim:, The aim of this study was to evaluate the quality of the performance of everyday activities in children with spina bifida. Methods:, Fifty children with spina bifida (of 65 children in a geographic cohort), aged 6 to14 years, were evaluated with Assessment of Motor and Process Skills. Results:, Compared with age-normative values, 60% of the children with spina bifida were found to have motor ability measures below 2 SD and 48% process ability measures below 2 SD. Most of the children with spina bifida had difficulties performing well-known everyday activities in an effortless, efficient and independent way, relating to both motor and process skills. The motor skills hardest to accomplish involved motor planning and the process skills hardest to accomplish were adaptation of performance and initiations of new steps, thus actually getting the task done. Conclusion:, To reach autonomy in life, children with spina bifida may need particular guidance to learn not only how to do things but also how to get things done. [source]