187 research outputs found

    Applied linguistics and mathematics education: More than words and numbers

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    The preceding set of papers has explored various aspects of the role of language in mathematics education. The papers reflect the work of individual contributors. An important part of our collaboration, however, has been the conversation between us. This paper reflects aspects of that conversation, as we draw together some of the themes that have emerged during our work. In particular, we discuss some of the implications of our analyses for theory, policy, practice and inter-disciplinarity in mathematics education and applied linguistics

    Teacher assessment as policy instrument: Contradictions and capacities

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    Assessment has been at center stage of educational reform in England and Wales in the past 15 years. This article argues that official educational assessment policy is essentially indifferent to the technical, pedagogic, and epistemological issues related to different forms of assessment. Policymakers are primarily concerned with “delivering” educational success in terms of reportable rising levels of attainment. The first part of this article provides a contextualized account of the use of assessment as an educational policy instrument and some of the consequences for pedagogy and curriculum provision. Our focal point here is on the assessment of English within the National Curriculum. The second section of the article amplifies our central argument—that policy is uninterested in the technical and educational issues involved in assessment—by offering a detailed critique of the limited and impoverished nature of the infrastructure and support available for teachers to carry out teacher assessment, with particular reference to the assessment of English for pupils whose first/home language is a language other than English. Research data are used to support our observations and arguments. We suggest that there is an urgent need to clarify the distinctions between summative and formative assessment, between the assessment of English as a first language and English as an Additional Language, and between a grammar-based view of English and a cross-curriculum discourse and communication-oriented view of English

    Polarized thermal radiation by layer-by-layer metallic emitters with sub-wavelength grating

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    Metallic thermal emitters consisting of two layers of differently structured nickel gratings on a homogeneous nickel layer are fabricated by soft lithography and studied for polarized thermal radiation. A thermal emitter in combination with a sub-wavelength grating shows a high extinction ratio, with a maximum value close to 5, in a wide mid-infrared range from 3.2 to 7.8 µm, as well as high emissivity up to 0.65 at a wavelength of 3.7µm. All measurements show good agreement with theoretical predictions. Numerical simulations reveal that a high electric field exists within the localized air space surrounded by the gratings and the intensified electric-field is only observed for the polarizations perpendicular to the top sub-wavelength grating. This result suggests how the emissivity of a metal can be selectively enhanced at a certain range of wavelengths for a given polarization

    Putting translanguaging into practice: A view from England

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    Our understandings of multilingualism have changed significantly over the last 50 years. Whilst there is broad agreement of the positive benefits of multilingualism, we are still debating how best to harness and make use of multilingualism with respect to curriculum and pedagogy in different contexts. Many teachers find themselves working around tensions between monolingual educational policies and multilingual classroom realities. Translanguaging offers us potential new and flexible ways of responding to the needs and practices of multilingual students and addressing gaps between policy and classroom realities. In this paper, we explore the opportunities and constraints of adopting translanguaging practices in publicly funded schools in England where greater school-based curriculum autonomy is being mooted. Our discussion is informed by an analysis of policy documents and teacher interview data, which allowed us to begin to map out an agenda for change with regard to the realisation of translanguaging pedagogies within state-funded educational contexts in England

    Soft lithography microlens fabrication and array for enhanced light extraction from organic light emitting diodes (OLEDs)

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    Provided are microlens arrays for use on the substrate of OLEDs to extract more light that is trapped in waveguided modes inside the devices and methods of manufacturing same. Light extraction with microlens arrays is not limited to the light emitting area, but is also efficient in extracting light from the whole microlens patterned area where waveguiding occurs. Large microlens array, compared to the size of the light emitting area, extract more light and result in over 100% enhancement. Such a microlens array is not limited to (O)LEDs of specific emission, configuration, pixel size, or pixel shape. It is suitable for all colors, including white, for microcavity OLEDs, and OLEDs fabricated directly on the (modified) microlens array

    Soft holographic interference lithography microlens for enhanced organic light emitting diode light extraction

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    Very uniform 2 μm-pitch square microlens arrays (μLAs), embossed on the blank glass side of an indium-tin-oxide (ITO)-coated 1.1 mm-thick glass, are used to enhance light extraction from organic light-emitting diodes (OLEDs) by ~100%, significantly higher than enhancements reported previously. The array design and size relative to the OLED pixel size appear to be responsible for this enhancement. The arrays are fabricated by very economical soft lithography imprinting of a polydimethylsiloxane (PDMS) mold (itself obtained from a Ni master stamp that is generated from holographic interference lithography of a photoresist) on a UV-curable polyurethane drop placed on the glass. Green and blue OLEDs are then fabricated on the ITO to complete the device. When the μLA is ~15 × 15 mm2, i.e., much larger than the ~3 × 3 mm2 OLED pixel, the electroluminescence (EL) in the forward direction is enhanced by ~100%. Similarly, a 19 × 25 mm2μLA enhances the EL extracted from a 3 × 3 array of 2 × 2 mm2 OLED pixels by 96%. Simulations that include the effects of absorption in the organic and ITO layers are in accordance with the experimental results and indicate that a thinner 0.7 mm thick glass would yield a ~140% enhancement

    Fabrication of photonic band gap materials using microtransfer molded templates

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    A method of manufacturing photonic band gap structures operable in the optical spectrum has been presented. The method comprises the steps of creating a patterned template for an elastomeric mold, fabricating an elastomeric mold from poly-dimethylsiloxane (PDMS) or other suitable polymer, filling the elastomeric mold with a second polymer such as epoxy or other suitable polymer, stamping the second polymer by making contact with a substrate or multilayer structure, removing the elastomeric mold, infiltrating the multilayer structure with ceramic or metal, and heating the multilayer structure to remove the second polymer to form a photonic band gap structure

    Semicrystalline woodpile photonic crystals without complicated alignment via soft lithography

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    We report the fabrication and characterization of woodpile photonic crystals with up to 12 layers through titania nanoparticle infiltration of a polymer template made by soft lithography. Because the complicated alignment in the conventional layer-by-layer fabrication associated with diamondlike symmetry is replaced by a simple 90° alignment, the fabricatedphotonic crystal has semicrystalline phase. However, the crystal performs similarly to a perfectly aligned crystal for the light propagation integrated from the surface normal to 30° at the main photonic band gap

    High aspect ratio nanoscale metallic structures as transparent electrodes

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    A novel technique based on the two polymer micro-transfer molding (2-P μTM) for fabricating one dimensional (1D) high aspect ratio nanoscale metallic structures is presented and experimental characterization is described. Glancing angle metal deposition and physical argon ion milling (etching) techniques were also employed in processing. The resulting metallic structures have high transmission (~80%) in the visible spectrum and have superior electrical conductivity (resistance from 2.4 -7.3 Ω) compared to standard indium-tin oxide (ITO) glass. Thus, the high aspect ratio metallic structures are a promising alternative with potentially superior performances to ITO glass as transparent electrodes for organic solar cells

    Photonic bandgaps of conformally coated structures

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    Polymeric molds of the layer-by-layer photonic crystal can be economically synthesized with a microtransfer molding technique. The refractive indices of these molds are low, preventing formation of a photonic bandgap. We find that such molds can be conformally coated with higher-index material. Photonic band calculations find structures in which conformally coated layer-by-layer molds have complete bandgaps for both titania and silicon coatings. Large stop bands exist in the 001 stacking direction. Feasibility of experimental conformal coating of the molds has been demonstrated with a titania-coated polyurethane mold, which shows optical features in agreement with simulations of reflection and transmission
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