479 research outputs found

    Ortho-Fluorination of azophenols increases the mesophase stability of photoresponsive hydrogen-bonded liquid crystals

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    Photoresponsive liquid crystals (LCs) whose alignment can be controlled with UV-Visible light are appealing for a range of photonic applications. From the perspective of exploring the interplay between the light response and the self-assembly of the molecular components, supramolecular liquid crystals are of particular interest. They allow elaborating the structure-property relationships that govern the optical performance of LC materials by subtle variation of the chemical structures of the building blocks. Herein we present a supramolecular system comprising azophenols and stilbazoles as hydrogen-bond donors and acceptors, respectively, and show that ortho-fluorination of the azophenol dramatically increases the thermal stability of the LC phases, an important characteristics in their further utilization in photonics. The systems exhibit fast photoinduced order-disorder transitions, and rapid recovery of the liquid-crystalline state once the light irradiation is ceased, due to the photochemical properties of azophenols

    Spin polarization of Auger- and of photoelectrons from barium atoms exposed to circularly polarized radiation and their cross comparison

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    Kuntze R, Salzmann M, Böwering N, Heinzmann U. Spin polarization of Auger- and of photoelectrons from barium atoms exposed to circularly polarized radiation and their cross comparison. Zeitschrift für Physik D: Atoms, Molecules and Clusters. 1994;30(2-3):235-237.New results of spin polarization of both photoelectrons and Auger electrons are reported after 5[Rho] photoionization of free Ba atoms with circularly polarized light. A substantial polarization transfer from the spin polarized photons to the spin polarized photoelectrons and via the hole state orientation to the spin polarized Auger-electrons is observed. The cross comparison of the results for photoelectrons and Auger-electrons allows a quantitative test of the assumed two step model where both electron-emission processes occur in sequence

    CUSTOM-BUILT WIRELESS PRESSURE SENSING INSOLES FOR DETERMINING CONTACT-TIMES IN 60M MAXIMAL SPRINT RUNNING

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    The purpose of this study was to evaluate a custom-built wireless pressure sensing insole system for recording ground contact times in sprinting. Despite interest in the foot contact time/running velocity relationship, no study has examined the contact times in a maximal 60 m sprint. Insole data were collected on three athletes during maximal indoor sprint runs. Simultaneous kinematic data for start and maximum velocity phases were recorded with a CODA system to validate insole contact times and determine velocity. Insole derived contact times were accurate to ±4 ms. Preliminary data indicate a usable contact time/velocity relationship. It is anticipated that these data will provide support for the use of wireless technology in sprint performance monitoring, and facilitate novel insights into the contact time/sprint running velocity relationship

    Agriculture's prominence in the INDCs

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    Analysis of agriculture in countries’ climate change mitigation and adaptation strategies finds: Most Parties to the UNFCCC include agriculture in their mitigation targets (80%) and adaptation strategies (64%); Non-annex 1 Parties note the need for international financial support to implement their INDCs and raise the ambition of their contributions; For countries to meet their targets, climate finance will need to address agriculture
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