34 research outputs found

    Food neophobia and mealtime food consumption in 4-5 year old children.

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    Background: Previous research has documented a negative association between maternal report of child food neophobia and reported frequency of consumption of fruit, vegetables, and meat. This study aimed to establish whether neophobia is associated with lower intake of these food types in naturalistic mealtime situations. Methods: One hundred and nine parents of 4–5 year olds completed questionnaires which included a six-item version of the Child Food Neophobia Scale (CFNS). The children took part in a series of 3 test lunch meals at weekly intervals at school at which they were presented with: chicken, cheese, bread, cheese crackers, chocolate biscuits, grapes and tomatoes or carrot sticks. Food items served to each child were weighed before and after the meal to assess total intake of items in four categories: Fruit and vegetables, Protein foods, Starchy foods and Snack foods. Pearson Product Moment Correlations and independent t tests were performed to examine associations between scores on the CFNS and consumption during lunches. Results: Neophobia was associated with lower consumption of fruit and vegetables, protein foods and total calories, but there was no association with intake of starch or snack foods. Conclusion: These results support previous research that has suggested that neophobia impacts differentially on consumption of different food types. Specifically it appears that children who score highly on the CFNS eat less fruit, vegetables and protein foods than their less neophobic peers. Attempts to increase intake of fruit, vegetables and protein might usefully incorporate strategies known to reduce the neophobic response

    Superconducting On-Chip Spectrometery for Millimeter-submillimeter Wave Astronomy

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    Since the birth of astrophysics, astronomers have been using free-space optics to analyze light falling on Earth. In the future however, thanks to the advances in photonics and nanoscience/nanotechnology, much of the manipulation of light might be carried out using not optics but confined waveguides, or circuits, on a chip. This new generation of instruments will be not only extremely compact, but also powerful in performance because the integration enables a greater degree of multiplexing. The benefit is especially profound for space- or air-borne observatories, where size, weight, and mechanical reliability are of top priority. Recently, several groups around the world are trying to integrate ultra-wideband (UWB), low-resolution spectrometers for millimeter-submillimeter waves onto microchips, using superconducting microelectronics. The scope of this Paper is to provide a general introduction and a review of the state-of-the-art of this rapidly advancing field.MicroelectronicsElectrical Engineering, Mathematics and Computer Scienc

    DESHIMA: Integrated Superconducting Spectrometer for Wideband Submillimeter Astronomy

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    The integrated superconducting spectrometer (ISS) enables ultra-wideband, large field-of-view integral-field-spectrometer designs for mm-submm wave astronomy. DESHIMA (Deep Spectroscopic High-redshift Mapper) is a single-pixel ISS spectrometer for the ASTE 10-m telescope, designed to observe the 220-440 GHz band in a single shot, corresponding to a [CII]-line redshift range of z=3.3-7.6.In this colloquium I will present the instrument concept, design, and first on-sky results of DESHIMA, obtained from October to December 2017 on the ASTE telescope. On the ISS chip of DESHIMA, the signal is captured by a lens-antenna and subsequently travels through a coplanar waveguide made of superconducting NbTiN, from which NbTiN bandpass filters branch out to divide the signal into separate frequency channels. At the output of each filter is a NbTiN/Al hybrid microwave kinetic inductance detector (MKID). The first generation of DESHIMA (DESHIMA 1.0) is a 1-pixel spectrometer that covers the 332-377 GHz band with 49 spectral channels, offering a spectral resolution F/dF ~ 380. We present detection of molecular emission lines from various sources, including a weakly redshifted CO line from the luminous infrared galaxy VV 114. The on-sky performance shows excellent agreement between the design and laboratory measurement in terms of the sensitivity, optical efficiency and beam pattern. In addition, we present wideband spectral maps of extended sources to demonstrate the potential of the ISS technology towards spectroscopic direct imaging. Ongoing upgrades towards the octave-bandwidth full system (DESHIMA 2.0) include the development of a filterbank chip with ~350 channels and higher optical efficiency, a wideband quasioptical design, and observing methods for efficiently removing the atmosphere. DESHIMA is a collaboration between the Netherlands (TU Delft, SRON, Leiden University, +) and Japan (University of Tokyo, Nagoya University, Kitami Institute of Technology, NAOJ, +) Reference Endo et al., "First light demonstration of the integrated superconducting spectrometer," Nature Astronomy 3, 989-996 (2019) https://arxiv.org/abs/1906.10216 DESHIMA website: http://deshima.ewi.tudelft.nlRESCEU Colloquium No. 46, December 10, 2020, 17:00-18:00Tera-Hertz Sensin

    Wideband Sub-mm Wave Superconducting Integrated Filter-bank Spectrometer

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    The design of an octave bandwidth sub-mm wave superconducting on-chip filter-bank spectrometer for Astronomy is presented. An array of THz band-pass filters subdivides the bandwidth 220-440 GHz into channels with a spectral resolution of 400 and an average maximum coupling strength f/ Delta {f} of 40%. The filter-bank performance is assessed by means of a transmission line formalism that approximates its behavior. The chip is under fabrication and its measurements will follow.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Tera-Hertz Sensin

    A Wideband Leaky Lens Antenna with Frequency-Stable Beams for DESHIMA Spectrometer

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    DESHIMA (Deep Spectroscopic High-redshift Mapper) is an instrument aiming at efficiently making spectroscopic redshift measurements of sub-mm wave galaxies (SMGs), thereby providing about the formation and the evolution of stars and galaxies. The aim of this work is to provide a preliminary study into the design of a wideband leaky lens antenna coupled quasi-optical system within a 1:3 bandwidth. We propose a multi-pixel solution where the virtual sources are located on the lens focal plane. The design is able to provide frequency stable beams to achieve high Gaussian coupling efficiency within the entire bandwidth. We will evaluate the performance of the quasi-optical system design in terms of its Gaussicity and scan loss. The design is specifically targeted at the ASTE telescope located in Atacama, Chile.Accepted Author ManuscriptTera-Hertz SensingQN/Quantum Nanoscienc

    Sub-mm-Wave Superconducting On-Chip Filter Bank for Astronomy

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    A superconducting on-chip microstrip filter bank spectrometer prototype for Far-Infrared (FIR) Astronomy is presented. The measurements showcase its capabilities towards moderate spectral resolution (f/\Delta f\sim 500) broadband FIR spectroscopy. In this sub-mm-wave filter bank, each spectral channel consists of an 'I-shaped' microstrip THz bandpass filter that couples the radiation to a Microwave Kinetic Inductance Detector (MKID) for a background limited detection and a scalable frequency-multiplexed microwave readout.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Tera-Hertz SensingQN/van der Zant LabQN/Quantum Nanoscienc

    Combined ultraviolet- and electron-beam lithography with Micro-Resist-Technology GmbH ma-N1400 resist

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    We present a "mix-and-match"process to create large structures with submicrometer features by combining UV contact lithography and 100 kV electron-beam lithography in a single layer of negative-tone resist: Micro-Resist-Technology ma-N1405. The resist is successfully applied for the fabrication of an on-chip terahertz spectrometer, where the design requires 450 nm wide lines and 300 nm wide trenches in a 150 nm thick niobium-titanium-nitride layer, tolerating errors of ± 30 nm. We use a resist thickness of 500 nm, optimized to allow reliable SF 6/O 2-based reactive ion etching of structures with 30 nm accuracy. We find that resist requires an electron-beam cross-linking dose of 1100 μ C / c m 2 for an acceleration voltage of 100 kV in combination with a 180 s 100 °C bake on a hot plate and 45 s development. The smallest resist bars made with our dedicated recipe are 100 nm wide, with the smallest gaps about 300 nm. The difference between the designed and realized feature size is between 2 and 30 nm for structures up to 700 nm wide. The optical exposure dose is 300 m J / c m 2 for the same development time and is optimized to produce a positive sloped edge profile allowing good step coverage for subsequent layers. The resist can be applied, shipped, and processed in a time span of a couple of days without notable deterioration of patterning quality. Tera-Hertz Sensin

    Simulating the Radiation Loss of Superconducting Submillimeter Wave Filters and Transmission Lines Using Sonnet EM

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    Superconducting resonators and transmission lines are fundamental building blocks of integrated circuits for millimeter-submillimeter astronomy. Accurate simulation of radiation loss from the circuit is crucial for the design of these circuits because radiation loss increases with frequency, and can thereby deteriorate the system performance. Here we show a stratification for a 2.5-dimensional method-of-moment simulator Sonnet EM that enables accurate simulations of the radiative resonant behavior of submillimeter-wave coplanar resonators and straight coplanar waveguides (CPWs). The Sonnet simulation agrees well with the measurement of the transmission through a coplanar resonant filter at 374.6 GHz. Our Sonnet stratification utilizes artificial lossy layers below the lossless substrate to absorb the radiation, and we use co-calibrated internal ports for de-embedding. With this type of stratification, Sonnet can be used to model superconducting millimeter-submillimeter wave circuits even when radiation loss is a potential concern.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Tera-Hertz Sensin

    Terahertz Band-Pass Filters for Wideband Superconducting On-chip Filter-bank Spectrometers

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    A superconducting microstrip half-wavelength resonator is proposed as a suitable band-pass filter for broadband moderate spectral resolution spectroscopy for terahertz (THz) astronomy. The proposed filter geometry has a free spectral range of an octave of bandwidth without introducing spurious resonances, reaches a high coupling efficiency in the pass-band and shows very high rejection in the stop-band to minimize reflections and cross-talk with other filters. A spectrally sparse prototype filter-bank in the band 300400 GHz has been developed employing these filters as well as an equivalent circuit model to anticipate systematic errors. The fabricated chip has been characterized in terms of frequency response, reporting an average peak coupling efficiency of 27% with an average spectral resolution of 940.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Tera-Hertz Sensin

    Suppression of radiation loss in high kinetic inductance superconducting co-planar waveguides

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    We present a lab-on-chip technique to measure the very low losses in superconducting transmission lines at (sub-) mm wavelengths. The chips consist of a 100 nm-thick NbTiN Co-planar Waveguide (CPW) Fabry–Pérot (FP) resonator, coupled, on one side, to an antenna and, on the other side, to a Microwave Kinetic Inductance detector. Using a single frequency radiation source allows us to measure the frequency response of the FP around 350 GHz and deduce its losses. We show that the loss is dominated by radiation loss inside the CPW line that forms the FP and that it decreases with the decreasing linewidth and increasing kinetic inductance as expected. The results can be quantitatively understood using SONNET simulations. The lowest loss is observed for a CPW with a total width of 6 μm and corresponds to a Q-factor of ≈15 000.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Tera-Hertz Sensin
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