• Title/Summary/Keyword: University of Cambridge

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Crossover from weak anti-localization to weak localization in inkjet-printed Ti3C2Tx MXene thin-film

  • Jin, Mi-Jin;Um, Doo-Seung;Ogbeide, Osarenkhoe;Kim, Chang-Il;Yoo, Jung-Woo;Robinson, J. W. A.
    • Advances in nano research
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    • v.13 no.3
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    • pp.259-267
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    • 2022
  • Two-dimensional (2D) transition metal carbides/nitrides or "MXenes" belong to a diverse-class of layered compounds, which offer composition- and electric-field-tunable electrical and physical properties. Although the majority of the MXenes, including Ti3C2Tx, are metallic, they typically show semiconductor-like behaviour in their percolated thin-film structure; this is also the most common structure used for fundamental studies and prototype device development of MXene. Magnetoconductance studies of thin-film MXenes are central to understanding their electronic transport properties and charge carrier dynamics, and also to evaluate their potential for spin-tronics and magnetoelectronics. Since MXenes are produced through solution processing, it is desirable to develop deposition strategies such as inkjet-printing to enable scale-up production with intricate structures/networks. Here, we systematically investigate the extrinsic negative magnetoconductance of inkjetprinted Ti3C2Tx MXene thin-films and report a crossover from weak anti-localization (WAL) to weak localization (WL) near 2.5K. The crossover from WAL to WL is consistent with strong, extrinsic, spin-orbit coupling, a key property for active control of spin currents in spin-orbitronic devices. From WAL/WL magnetoconductance analysis, we estimate that the printed MXene thin-film has a spin orbit coupling field of up to 0.84 T at 1.9 K. Our results and analyses offer a deeper understanding into microscopic charge carrier transport in Ti3C2Tx, revealing promising properties for printed, flexible, electronic and spinorbitronic device applications.

Orienting the superficial inferior epigastric artery (SIEA) pedicle in a stacked SIEA-deep inferior epigastric perforator free flap configuration for unilateral tertiary breast reconstruction

  • Yu, Ya-han;Ghorra, Dina;Bojanic, Christine;Aria, Oti N.;MacLennan, Louise;Malata, Charles M.
    • Archives of Plastic Surgery
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    • v.47 no.5
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    • pp.473-477
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    • 2020
  • Superficial inferior epigastric artery (SIEA) flaps represent a useful option in autologous breast reconstruction. However, the short-fixed pedicle can limit flap inset options. We present a challenging flap inset successfully addressed by de-epithelialization, turnover, and counterintuitive rotation. A 47-year-old woman underwent left tertiary breast reconstruction with stacked free flaps using right deep inferior epigastric perforator and left SIEA vessels. Antegrade and retrograde anastomoses to the internal mammary (IM) vessels were preferred; additionally, the thoracodorsal vessels were unavailable due to previous latissimus dorsi breast reconstruction. Optimal shaping required repositioning of the lateral ends of the flaps superiorly, which would position the ipsilateral SIEA hemi-flap pedicle lateral to and out of reach of the IM vessels. This problem was overcome by turning the SIEA flap on its long axis, allowing the pedicle to sit medially with the lateral end of the flap positioned superiorly. The de-epithelialized SIEA flap dermis was in direct contact with the chest wall, enabling its fixation. This method of flap inset provides a valuable solution for medializing the SIEA pedicle while maintaining an aesthetically satisfactory orientation. This technique could be used in ipsilateral SIEA flap breast reconstructions that do not require a skin paddle, as with stacked flaps or following nipple-sparing mastectomy.

Wireless sensor networks for underground railway applications: case studies in Prague and London

  • Bennett, Peter J.;Soga, Kenichi;Wassell, Ian;Fidler, Paul;Abe, Keita;Kobayashi, Yusuke;Vanicek, Martin
    • Smart Structures and Systems
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    • v.6 no.5_6
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    • pp.619-639
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    • 2010
  • There is increasing interest in using structural monitoring as a cost effective way of managing risks once an area of concern has been identified. However, it is challenging to deploy an effective, reliable, large-scale, long-term and real-time monitoring system in an underground railway environment (subway / metro). The use of wireless sensor technology allows for rapid deployment of a monitoring scheme and thus has significant potential benefits as the time available for access is often severely limited. This paper identifies the critical factors that should be considered in the design of a wireless sensor network, including the availability of electrical power and communications networks. Various issues facing underground deployment of wireless sensor networks will also be discussed, in particular for two field case studies involving networks deployed for structural monitoring in the Prague Metro and the London Underground. The paper describes the network design, the radio propagation, the network topology as well as the practical issues involved in deploying a wireless sensor network in these two tunnels.

Routes to Improving Performance of Solution-Processed Organic Thin Film Transistors

  • Li, Flora M.;Hsieh, Gen-Wen;Nathan, Arokia;Beecher, Paul;Wu, Yiliang;Ong, Beng S.;Milne, William I.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.1051-1054
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    • 2009
  • This paper investigates approaches for improving effective mobility of organic thin film transistors (OTFTs). We consider gate dielectric optimization, whereby we demonstrated >2x increase in mobility by using a silicon-rich silicon nitride ($SiN_x$) gate dielectric for polythiophene-based (PQT) OTFTs. We also engineer the dielectric-semiconductor ($SiN_x$-PQT) interface to attain a 27x increase in mobility (up to 0.22 $cm^2$/V-s) using an optimized combination of oxygen plasma and OTS SAM treatments. Augmentative material systems by combining 1-D nanomaterials (e.g., carbon nanotubes, zinc oxide nanowires) in an organic matrix for nanocomposite OTFTs provided a further boost in device performance.

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Topics in TFT device physics and modelling

  • Migliorato, P.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07b
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    • pp.929-935
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    • 2005
  • This paper contains a review of methods to analise static and dynamic properties of trap states in TFTs. The Gap Density of States is extracted from C-V and I-V characteristics. Switch on transients and small signal ac measurements are used in conjunction with simulation and an analytic model to extract traps dynamic parameters.

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Adult stem cell lineage tracing and deep tissue imaging

  • Fink, Juergen;Andersson-Rolf, Amanda;Koo, Bon-Kyoung
    • BMB Reports
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    • v.48 no.12
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    • pp.655-667
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    • 2015
  • Lineage tracing is a widely used method for understanding cellular dynamics in multicellular organisms during processes such as development, adult tissue maintenance, injury repair and tumorigenesis. Advances in tracing or tracking methods, from light microscopy-based live cell tracking to fluorescent label-tracing with two-photon microscopy, together with emerging tissue clearing strategies and intravital imaging approaches have enabled scientists to decipher adult stem and progenitor cell properties in various tissues and in a wide variety of biological processes. Although technical advances have enabled time-controlled genetic labeling and simultaneous live imaging, a number of obstacles still need to be overcome. In this review, we aim to provide an in-depth description of the traditional use of lineage tracing as well as current strategies and upcoming new methods of labeling and imaging.

Explorations of Evidence-based Policymaking (EBPM) for Reconciling Science and Policy: Developing a Conceptual Framework for Improved Understanding of EBPM in Wind Industry Emergence

  • Lee, Kyounglim;Platts, Jim;Minshall, Tim
    • STI Policy Review
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    • v.6 no.2
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    • pp.146-173
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    • 2015
  • This study explores how to reconcile science and policy in the wind energy sector by providing a conceptual framework for better understanding evidence-based policymaking (EBPM). Regarding this framework, the core issue is to discover how knowledge is formed over time, and which factors affect this knowledge formation. Comparative cases of wind industry emergence in Spain and Britain are examined. This analysis shows that knowledge formation initially starts in the scientific arena in parallel with its formation in the practical, and is followed by political knowledge formation near the beginning of commercial projects. Regarding knowledge formation, three more comparisons are made between wind industry emergence in Spain and Britain: the different approaches to R&D projects, the different adoptions of supporting measures, and the different ways of coping with public opposition. The factors affecting the comparisons are mainly perceptions of energy supply, nuclear power, environment and science and technology. Communication and unfamiliarity are likely to affect the comparisons in EBPM.