145 research outputs found

    Macromolecules

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    We present a method for patterning substrates with a regular mesh of stable radical groups. Resulting from advanced block copolymer synthesis and annealing techniques, stable radical groups on a polymer backbone phase separate from the second block and arrange in ordered block copolymer morphologies. These meshes align in large regular patterns upon sample preparation on macroscopically structured substrates. Patterned stable radical groups may find application in selective catalysis, energy storage, data storage, or optical gratings. In addition, gas permeable membranes with reactive sites or charge storage zones with regular spacings in redox batteries may be feasible by our approach

    Sustainable polyimidazolium networks as versatile hydrogel materials

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    Stability of the zwitterionic liquid butyl-methyl-imidazol-2-ylidene borane

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    Modification of the C2 position of the standard 1-butyl-3-methyl imidazolium cation by a borohydride group leads to a zwitterionic liquid (ZIL). The resulting imidazol-2-ylidene borane ZIL is liquid at room temperature. Dynamic viscosity as well as thermal and electrochemical stability are investigated. Thermal decomposition follows a similar pathway as in comparable imidazolium ionic liquids. The surprisingly low viscosity and good reductive stability make it a promising candidate for electrochemical applications

    Dentale Altersbestimmung an hessischen Kindern, Ermittlung der intermaxillären Varianz

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    Анализ систем оценки информационно коммуникационных компетенций

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    The article considers the methods of development of information-analytical system of formation of information-communicative competence of students through the portal of "Electronic University of information technology"

    Halogen free 1,2,3- and 1,2,4-triazolide based ionic liquids : synthesis and properties

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    Triazoles have been successfully used as building blocks to create "fully organic" ILs featuring on both sides organic ions, i.e., 1,2,3- or 1,2,4-triazolide anions and 1,2,4-triazolium or imidazolium cations. Glass transition temperatures, densities and viscosities of these ILs were determined. Their electrochemical and thermal stability, and also conductivity, are higher than those for known ILs

    Polymerization in carbone : a novel method for the synthesis of more sustainable electrodes and their application as cathodes for lithium–organic energy storage materials based on vanillin

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    Sustainable energy storage materials are needed to implement necessary transitions to a more sustainable society. Therefore, we present novel vanillin (and thus ultimately possibly lignin)-derived electrode materials for lithium-ion-based energy storage systems. In the present approach, vanillin is first modified in two sustainable steps to afford bisvanillonitrile (BVN). The precursor materials for the electrodes are made from BVN and carbon black and are subsequently treated in the atmosphere of triflic acid in order to polymerize BVN. Used as a cathode material in a lithium-ion-based energy storage device, the resulting material shows capacities up to 90 mAh g–1 (respective to the whole electrode mass). This extraordinary performance can be attributed to a combination of non-Faradaic and Faradaic charge storage involving quinone units, which are abundantly found in the polymer backbone. In contrast to conventional organic electrode materials, excellent contact to carbon as a conductive additive is established by performing the polymerization in a mixture with carbon (in carbone), allowing the omission of additional unsustainable binder materials. Due to the sustainable synthesis and good performance, such sustainable electrodes may be applied in future energy storage devices

    Crystal slow extraction of positrons from DAΦNE: the SHERPA project

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    The SHERPA project aim is to develop an efficient technique to extract a positron beam from one of the accelerator rings composing the DAΦNE complex at the Frascati National Laboratory of INFN, setting up a new beam line able to deliver positron spills of O(ms) length, excellent beam energy spread and emittance. The most common approach to slowly extract from a ring is to increase betatron oscillations approaching a tune resonance in order to gradually eject particles from the circulating beam. SHERPA proposes a paradigm change using coherent processes in bent crystals to kick out positrons from the ring, a cheaper and less complex alternative. A description of this innovative nonresonant extraction technique is reported in this manuscript, including its performance preliminary estimation
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