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Zhu, C. (author), Klapwijk, R.M. (author)Encoding intangible data variables with visual, spatial, and physical properties demands a high level of spatial reasoning. The ability to reason spatially is widely deemed critical to science, technology, engineering, arts, and mathematics (STEAM) learning. While much research has explored the relationship between learning with...conference paper 2023
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Zhu, C. (author), Klapwijk, R.M. (author)Spatial thinking is embedded in science, technology, engineering, arts, and mathematics (STEAM) learning. Design and Technology education inherently encompasses a wide range of spatial activities, such as mentally transforming objects and materials to form representations of design ideas, visually communicating ideas, and creating 2D and 3D...conference paper 2022
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Klapwijk, R.M. (author), Stables, Kay (author), Blom, Nicolaas (author), Canty, Donal (author), Dagan, Osnat (author), Hartell, Eva (author), Khunyakari, Ritesh (author)This paper reports on a pilot project focused on the use of the formative assessment resource Make Design Learning Visible (MDLV) in different national settings. The MDLV resource centers on a design model involving seven interactive design skills and a formative assessment model involving five strategies. A team of researchers from seven...conference paper 2022
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Klapwijk, M.D. (author), Lloyd, Thomas (author), Vaz, Guilherme (author), van Terwisga, T.J.C. (author)<br/>conference paper 2019
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Liebrand, Rens (author), Klapwijk, M.D. (author), Lloyd, Thomas (author), Vaz, Guilherme (author), Lopes, Rui (author)A sensitivity analysis of the transitional flow over a NACA66<sub>2</sub> - 415 foil and the elliptical Arndt wing is carried out. The SST turbulence model is complemented with the ? - Re <sup>~</sup><sub>?t</sub> transition model to determine the effect of varying turbulence intensity and eddy-viscosity ratio on the integral quantities and...conference paper 2019
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Roël-Looijenga, A. (author), Klapwijk, R.M. (author), de Vries, M.J. (author)In this paper, pupils’ design behaviour is regarded as an expression of active knowledge acquisition. Four cases of building a task structure, which supports effective discovery learning, were investigated. We focus on simple characteristics in a model to explain the effects of the structure on task execution. It reconciles<br/>the advantages of...conference paper 2018
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Effects of Convergent and Divergent Feedback on Creative Thinking During Children’s Design ProcessesSchut, A. (author), Klapwijk, R.M. (author), Gielen, M.A. (author)This paper explores patterns in the feedback preceding instances of design fixation in children (age 9 to 11) carrying out a co-design project. Our goal is to find ways to improve the early mastering of their divergent (DT) and convergent thinking (CT) skills, which in turn will help the children to develop their creative abilities. Previous...conference paper 2018
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Shcherbatenko, M. (author), Lobanov, Y. (author), Benderov, O. (author), Shurakov, A. (author), Ignatov, A. (author), Titova, N. (author), Finkel, M. (author), Maslennikov, S. (author), Kaurova, N. (author), Voronov, B.M. (author), Rodin, A. (author), Klapwijk, T.M. (author), Gol'tsman, G.N. (author)We report on design and characterization of a superconducting Hot Electron Bolometer Mixer integrated with a logarithmic spiral antenna for mid-IR range observations. The antenna parameters have been adjusted to achieve the ultimate performance at 10 ?m (30 THz) range where O3, NH3, CO2, CH4, N2O, . lines in the Earth’s atmosphere, in planetary...conference paper 2015
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- Van Doorn, F.A.P. (author), Klapwijk, R. (author) conference paper 2013
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Ren, Y. (author), Gao, J.R. (author), Hovenier, J.N.Higgins, R. (author), Zhang, W. (author), Bell, A. (author), Klein, B. (author), Klapwijk, T.M. (author)High-resolution heterodyne spectrometers operating at above 2 THz are crucial for detecting, e.g., the HD line at 2.7 THz and oxygen OI line at 4.7 THz in astronomy. The potential receiver technology is a combination of a hot electron bolometer (HEB) mixer and a THz quantum cascade laser (QCL) local oscillator (LO).Here we report the first...conference paper 2010
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Khudchenko, A. (author), Zijlstra, T. (author), Klapwijk, T. et al (author)The ALMA Band 9 receiver cartridge (600-720 GHz) based on Dual Sideband (DSB) superconductor-insulatorsuperconductor (SIS) mixer is currently in full production. In the case of spectral line observations, the integration time to reach a certain signal-to-noise level can be reduced by about a factor of two by rejecting an unused sideband. The...conference paper 2010
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Zhang, W. (author), Gao, J.R. (author), Khosropanah, P. (author), Bansal, T. (author), Klapwijk, T.M. (author), Miao, W. (author), Shi, S.C. (author)We report the sensitivity of a superconducting NbN hot electron bolometer mixer integrated with a tight spiral antenna at 5.3 THz. Using a measurement setup with black body calibration sources and a beam splitter in vacuo, and an antireflection coated Si lens, we obtained a double sideband receiver noise temperature of 1150 K, which is 4.5 times...conference paper 2010
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Barends, R. (author), Van Vliet, S. (author), Baselmans, J.J.A. (author), Yates, S.J.C. (author), Gao, J.R. (author), Klapwijk, T.M. (author)We present measurements of the quasiparticle relaxation time in Ta superconducting films shaped as planar resonators using the response of the complex conductivity to photon flux. These films have been implanted with magnetic (Mn) as well as non-magnetic atoms (Al). We find a significant decrease of the relaxation time with increasing impurity...conference paper 2009
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Khosropanah, P. (author), Laauwen, W.M. (author), Hajenius, M. (author), Gao, J.R. (author), Klapwijk, T.M. (author)We have studied the sensitivity of a superconducting NbN hot electron bolometer mixer integrated with a spiral antenna at 4.3 THz. Using hot/cold blackbody loads and a beam splitter all in vacuum, we measured a double sideband receiver noise temperature of 1300 K at the optimum local oscillator (LO) power of 330 nW, which is about 12 times the...conference paper 2008
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Smith, H. (author), Buckle, J. (author), Hills, R. (author), Bell, G. (author), Richer, J. (author), Curtis, E. (author), Withington, S. (author), Leech, J. (author), Williamson, R. (author), Klapwijk, T.M. (author)This paper describes the key design features and performance of HARP, an innovative heterodyne focal-plane array receiver designed and built to operate in the submillimetre on the James Clerk Maxwell Telescope (JCMT) in Hawaii. The 4x4 element array uses SIS detectors, and is the first sub-millimetre spectral imaging system on the JCMT. HARP...conference paper 2008
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De Graauw, T. (author), Whyborn, N. (author), Helmich, F. (author), Dieleman, P. (author), Roelfsema, P. (author), Caux, E. (author), Phillips, T. (author), Stutzki, J. (author), Beintema, D. (author), Klapwijk, T. (author)This paper describes the Heterodyne Instrument for the Far-Infrared (HIFI), to be launched onboard of ESA's Herschel Space Observatory, by 2008. It includes the first results from the instrument level tests. The instrument is designed to be electronically tuneable over a wide and continuous frequency range in the Far Infrared, with velocity...conference paper 2008
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Khosropanah, P. (author), Laauwen, W.M. (author), Gao, J.R. (author), Hajenius, M. (author), Hovenier, J.N. (author), Klapwijk, T.M. (author)We have characterized a heterodyne receiver based on an NbN hot electron bolometer integrated with spiral antenna as mixer and an optically pumped FIR ring laser at 4.3 THz as local oscillator (LO). We succeeded in measuring the receiver output power, responding to the hot/cold load, as a function of bias voltage at optimum LO power. From the...conference paper 2007
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Kasemann, C. (author), Güsten, R. (author), Heyminck, S. (author), Klein, B. (author), Klein, T. (author), Philipp, S.D. (author), Korn, A. (author), Schneider, G. (author), Henseler, A. (author), Baryshev, A. (author), Klapwijk, T.M. (author)CHAMP+, a dual-color 2 × 7 element heterodyne array for operation in the 450 ?m and 350 ?m atmospheric windows is under development. The instrument, which is currently undergoing final evaluation in the laboratories, will be deployed for commissioning at the APEX telescope in August this year. With its state-of-the-art SIS detectors and wide...conference paper 2006
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De Lange, G. (author), Jackson, B.D. (author), Jochemsen, M. (author), Laauwen, W.M. (author), De Jong, L. (author), Kroug, M. (author), Zijlstra, T. (author), Klapwijk, T.M. (author)We describe the performance of the Band 3 and Band 4 Flight Model mixer units for Herschel/HIFI Instrument. These units are part of the Focal Plane Unit of HIFI. The band 3 and 4 mixer units cover the 800-960 GHz and 960-1120 GHz frequency range and have a 4-8 GHz IF frequency band. The sensitivities of the mixers within the HIFI setting are...conference paper 2006
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Baselmans, J. (author), Hajenius, M. (author), Gao, J. (author), De Korte, P. (author), Klapwijk, T. (author), Voronov, B. (author), Gol'tsman, G. (author)NbN hot electron bolometer (HEB) mixers are at this moment the best heterodyne detectors for frequencies above 1 THz. However, the fabrication procedure of these devices is such that the quality of the interface between the NbN superconducting film and the contact structure is not under good control. This results in a contact resistance between...conference paper 2004
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