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See detailMacroscopic control of helix orientation in films dried from cholesteric liquid crystalline cellulose nanocrystal suspensions

Park, Ji Hyun; Noh, Junghyun UL; Schütz, Christina et al

in Chemphyschem : A European Journal of Chemical Physics and Physical Chemistry (2014), 15(7), 1477-1484

The intrinsic ability of cellulose nanocrystals (CNCs) to self-organize into films and bulk materials with helical order in a cholesteric liquid crystal is scientifically intriguing and potentially ... [more ▼]

The intrinsic ability of cellulose nanocrystals (CNCs) to self-organize into films and bulk materials with helical order in a cholesteric liquid crystal is scientifically intriguing and potentially important for the production of renewable multifunctional materials with attractive optical properties. A major obstacle, however, has been the lack of control of helix direction, which results in a defect-rich, mosaic-like domain structure. Herein, a method for guiding the helix during film formation is introduced, which yields dramatically improved uniformity, as confirmed by using polarizing optical and scanning electron microscopy. By raising the CNC concentration in the initial suspension to the fully liquid crystalline range, a vertical helix orientation is promoted, as directed by the macroscopic phase boundaries. Further control of the helix orientation is achieved by subjecting the suspension to a circular shear flow during drying. [less ▲]

Detailed reference viewed: 146 (6 UL)
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See detailMacroscopic-scale carbon nanotube alignment via self-assembly in lyotropic liquid crystals
Schymura, Stefan; Enz, Eva; Roth, Siegmar et al

in Synthetic Metals (2009), 159(21-22), 2177-2179

By dispersing carbon nanotubes (CNTs) in a lyotropic liquid crystalline matrix, uniaxial alignment of the nanotubes can easily be achieved over macroscopic areas. We briefly describe the principles behind ... [more ▼]

By dispersing carbon nanotubes (CNTs) in a lyotropic liquid crystalline matrix, uniaxial alignment of the nanotubes can easily be achieved over macroscopic areas. We briefly describe the principles behind the technique and then show that it can be applied to multiwall as well as single-wall nanotubes and that a variety of different dispersing materials can be used, from industrial surfactants to DNA. We also present a new microfluidics-based method for transferring the liquid crystal-dispersed CNTs to a substrate, maintaining a fair control of tube direction. (C) 2009 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 95 (1 UL)
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See detailThe mad genius: still alive and well
Baudson, Tanja Gabriele UL

in Frontiers in Psychology (2016), 7

Detailed reference viewed: 22 (2 UL)
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See detailMädchen und Jungen
Hornung, Caroline UL; Hoffmann, Danielle UL; Lorphelin, Dalia UL et al

in SCRIPT; EMACS (Eds.) PISA 2012. Nationaler Bericht Luxemburg (2013)

Detailed reference viewed: 66 (11 UL)
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See detailMade in Germany – Produced in America? How Dual Vocational Training Programs Can Help Close the Skills Gap in the United States
Powell, Justin J W UL; Fortwengel, Johann

in AICGS Issue Brief (2014), 47

Two of the strongest education systems and economies worldwide, the United States and Germany, have been among the key sources for models in skill formation emulated globally. Public and private ... [more ▼]

Two of the strongest education systems and economies worldwide, the United States and Germany, have been among the key sources for models in skill formation emulated globally. Public and private investments in skill formation have increased in both countries. Yet these systems maintain contrasting emphases: general and academic education in the U.S. and specific vocational training, in particular occupations, in Germany. Both countries continue to learn from each other as they compete in global education and labor markets—and continue their extensive bilateral cooperation. While both are meritocratic democracies with federal political structures, the educational institutions of Germany and the United States, especially those of vocational education and training, are quite different. This challenges the direct transfer of educational models. Yet there exists great interest among firms, politicians, and educators in praxis oriented, workplace-based, occupationally-focused education and training as it has developed over decades in Germany, Switzerland, and Austria. This is because it has become the backbone of robust export-driven economies and protected these societies from the economic crisis and high unemployment rates that the U.S. has recently suffered. Thus, the German model in vocational education and training, especially dual apprenticeship, has been widely discussed, most recently by President Barack Obama in his State of the Union address, in which he envisioned implementing elements of the German dual model to address the skills gap and unemployment in the U.S. economy. The current rise of dual studies in Germany—and functionally-equivalent programs in the United States described here—shows that employers are increasingly willing to collaborate with higher education institutions to recruit talent, train workers, and upgrade skills. [less ▲]

Detailed reference viewed: 358 (22 UL)
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See detailMade only in Germany? Internationalization and Transfer of Dual Study Programs
Graf, Lukas UL; Powell, Justin J W UL; Fortwengel, Johann et al

Scientific Conference (2014)

Germany, along with Switzerland and Austria, has a long tradition in the provision of dual apprenticeship training. However, since the late 1960s we see a new development with the rise of hybrid dual ... [more ▼]

Germany, along with Switzerland and Austria, has a long tradition in the provision of dual apprenticeship training. However, since the late 1960s we see a new development with the rise of hybrid dual study programs located at the nexus of vocational training and higher education. In recent years, this innovative training model has received increasing attention by policy makers in Germany – and abroad. In this context, our study first analyses the degree of internationalization of dual study programs in Germany. Secondly, we examine institutional conditions for the transfer of these programs to other countries: France, the US, Mexico, Brazil, and Qatar. The explorative analysis is based on a range of expert and stakeholder interviews in all six countries. We apply a neo-institutional comparative-historical approach. [less ▲]

Detailed reference viewed: 276 (19 UL)
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See detailMaDSAV: maintaining driving skills in semi-autonomous vehicles
Meschtscherjakov, Alexander; Mccall, Roderick UL; Louveton, Nicolas UL et al

in Adjunct Proceedings of the 7th International Conference on Automotive User Interfaces and Interactive Vehicular Applications (2015)

In the future autonomous vehicles will drive on our roads. It is unlikely that we will immediately move from manual to fully autonomous vehicles, instead the mix will change over time and include a large ... [more ▼]

In the future autonomous vehicles will drive on our roads. It is unlikely that we will immediately move from manual to fully autonomous vehicles, instead the mix will change over time and include a large number of semi-autonomous vehicles. As a result human drivers will need to take over in specific situations (e.g., when sensors fail) and there will be an interplay between autonomous systems and human agents. However, human drivers will not be able to practice driving so regularly. Our assumption is, that the reliance on semi-autonomous systems will lead to a deterioration in driving skills. In this paper, we present a three year project called MaDSAV (Maintaining Driving Skills in semi-Autonomous Vehicles), which tackles this problem. [less ▲]

Detailed reference viewed: 46 (0 UL)
See detailmafe - Educational Matlab framework for finite element analysis of structures.
Zilian, Andreas UL

Software (2016)

"mafe" is an educational MATLAB framework for finite element analysis of structures like rod, beams, slabs and plates that allows for (a) static linear analysis, (b) dynamic linear analysis in frequency ... [more ▼]

"mafe" is an educational MATLAB framework for finite element analysis of structures like rod, beams, slabs and plates that allows for (a) static linear analysis, (b) dynamic linear analysis in frequency and time domain. [less ▲]

Detailed reference viewed: 249 (28 UL)
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See detailMagie und Wunder. Elemente und Funktionen des Übernatürlichen in der epischen mittelhochdeutschen Literatur um 1200
Sieburg, Heinz UL

in Sieburg, Heinz; Voltmer, Rita; Weimann, Britta (Eds.) Hexenwissen. Zum Transfer von Magie- und Zauberei-Imaginationen in interdisziplinärer Perspektive (2017)

Detailed reference viewed: 153 (7 UL)
See detailMagnetic and free-layer properties of MgO/(Co)FeB/MgO structure: Dependence on CoFeB composition
Bersweiler, Mathias UL

Scientific Conference (2019, January 17)

Detailed reference viewed: 84 (6 UL)
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See detailMagnetic Control of the Chiroptical Plasmonic Surfaces
Zubritskaya, Irina; Maccaferri, Nicolò UL; Inchausti Ezeiza, Xabier et al

in Nano Letters (2018), 18(1), 302-307

A major challenge facing plasmon nanophotonics is the poor dynamic tunability. A functional nanophotonic element would feature the real-time sizable tunability of transmission, reflection of light's ... [more ▼]

A major challenge facing plasmon nanophotonics is the poor dynamic tunability. A functional nanophotonic element would feature the real-time sizable tunability of transmission, reflection of light's intensity or polarization over a broad range of wavelengths, and would be robust and easy to integrate. Several approaches have been explored so far including mechanical deformation, thermal, or refractive index effects, and all-optical switching. Here we devise an ultrathin chiroptical surface, built on two-dimensional nanoantennas, where the chiral light transmission is controlled by the externally applied magnetic field. The magnetic field-induced modulation of the far-field chiroptical response with this surface exceeds 100% in the visible and near-infrared spectral ranges, opening the route for nanometer-thin magnetoplasmonic light-modulating surfaces tuned in real time and featuring a broad spectral response. [less ▲]

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See detailMagnetic correlations in polycrystalline Tb0.15Co0.85
Bersweiler, Mathias UL; Bender, Philipp Florian UL; Peral Alonso, Inmaculada UL et al

in Journal of Physics: D Applied Physics (2020), 53

Detailed reference viewed: 62 (6 UL)
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See detailMagnetic domains and annealing-induced magnetic anisotropy in nanocrystalline soft magnetic materials
Suzuki, K.; Ito, N.; Saranu, S. et al

in Journal of Applied Physics (2008), 103(7), 7301-7303

The magnetic domains of nanocrystalline Fe84Nb6B10 annealed under static and rotating magnetic fields have been investigated by means of magneto-optical Kerr effect (MOKE) microscopy in order to clarify ... [more ▼]

The magnetic domains of nanocrystalline Fe84Nb6B10 annealed under static and rotating magnetic fields have been investigated by means of magneto-optical Kerr effect (MOKE) microscopy in order to clarify the origin of the dramatic magnetic softening brought about by rotating field annealing. The coercivity (Hc) values after static- and rotating-magnetic field annealings are 5.9 and 3.0  A/m, respectively. The MOKE image after static field annealing implies a highly coherent uniaxial anisotropy (Ku) in the sample whereas no sign of such a strong Ku is evident in the domain configuration after rotating field annealing. Our analytical solution of the random anisotropy model with additional Ku predicts that the fluctuating amplitude of the effective anisotropy (δK) in nanocrystalline Fe84Nb6B10 decreases from 20 to 11 J/m3 by removing Ku. The observed reduction of Hc may be attributed to this decrease in δK induced by rotating field annealing. [less ▲]

Detailed reference viewed: 157 (4 UL)
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See detailMagnetic field and gradient standards using permanent magnets: Design considerations, construction and validation by nuclear magnetic resonance
Perigo, Elio Alberto UL; Martin, Ramon Valls

in IEEE Transactions on Magnetics (2013), 49(8), 4717-4720

The construction and characterization of static magnetic density flux and gradient standards by using permanent magnets is presented. In the first case, the field homogeneity is high enough to be measured ... [more ▼]

The construction and characterization of static magnetic density flux and gradient standards by using permanent magnets is presented. In the first case, the field homogeneity is high enough to be measured by a nuclear magnetic resonance magnetometer, confirming the traceability of the standard. In the second case, a gradient standard is shown. The experimental results obtained by Hall probes are in agreement with theoretical calculations. Designing considerations about materials choice and mounting are also addressed. [less ▲]

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See detailMagnetic field-dependent spin structures of nanocrystalline holmium
Szary, Philipp; Kaiser, Daniel UL; Bick, Jens-Peter et al

in Journal of Applied Crystallography (2016), 49

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See detailMagnetic Guinier law
Michels, Andreas UL; Malyeyev, Artem UL; Titov, Ivan UL et al

in IUCrJ (2020), 7

Small-angle scattering of x-rays and neutrons is a routine method for the determination of nanoparticle sizes. The so-called Guinier law represents the low-q approximation for the small-angle scattering ... [more ▼]

Small-angle scattering of x-rays and neutrons is a routine method for the determination of nanoparticle sizes. The so-called Guinier law represents the low-q approximation for the small-angle scattering curve from an assembly of particles. The Guinier law has originally been derived for nonmagnetic particle-matrix-type systems, and it is successfully employed for the estimation of particle sizes in various scientific domains (e.g., soft matter physics, biology, colloidal chemistry, materials science). An important prerequisite for it to apply is the presence of a discontinuous interface separating particles and matrix. Here, we introduce the Guinier law for the case of magnetic small-angle neutron scattering (SANS) and experimentally demonstrate its applicability for the example of nanocrystalline cobalt. It is well- known that the magnetic microstructure of nanocrystalline ferromagnets is highly nonuniform on the nanometer length scale and characterized by a spectrum of continuously varying long-wavelength magnetization fluctuations, i.e., these systems do not manifest sharp interfaces in their magnetization profile. The magnetic Guinier radius depends on the applied magnetic field, on the magnetic interactions (exchange, magnetostatics), and on the magnetic anisotropy-field radius, which characterizes the size over which the magnetic anisotropy field is coherently aligned into the same direction. In contrast to the nonmagnetic conventional Guinier law, the magnetic version can be applied to fully dense random-anisotropy-type ferromagnets. [less ▲]

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See detailMagnetic Guinier Law
Malyeyev, Artem UL; Michels, Andreas UL

Poster (2019, June)

We introduce the Guinier law for the case of magnetic SANS and provide an analysis of experimental data on a Nd-Fe-B-based nanocomposite and on a rare-earth-free MnBi permanent magnet. The robustness of ... [more ▼]

We introduce the Guinier law for the case of magnetic SANS and provide an analysis of experimental data on a Nd-Fe-B-based nanocomposite and on a rare-earth-free MnBi permanent magnet. The robustness of this novel approach is discussed and the quantities derived are analyzed in the framework of the existing research literature. [less ▲]

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See detailMagnetic Interaction with Devices: A Pilot Study on Mobile Gaming
Afshari, Saeed UL; Popleteev, Andrei UL; McCall, Roderick UL et al

in Proceedings of NordiCHI '14, October 26 - 30 2014, Helsinki, Finland (2014, October 26)

This work-in-progress paper presents a study of interaction techniques for mobile devices, with a focus on gaming scenarios. We introduce and explore usability and performance aspects of a novel compass ... [more ▼]

This work-in-progress paper presents a study of interaction techniques for mobile devices, with a focus on gaming scenarios. We introduce and explore usability and performance aspects of a novel compass based control for tangible around-device interaction, and compare it with traditional mobile gaming controls, such as touchscreen thumbstick, swiping and tilt-based approaches. [less ▲]

Detailed reference viewed: 377 (27 UL)