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11.
Frederik Weber Georg Koller Robert Schennach Ingo Bernt Rene Eckhart 《Cellulose (London, England)》2013,20(6):2719-2729
In this paper the influence of charged species on the sheet strength of viscose fibres was investigated. Four samples of chemical modified viscose fibres, as well as a reference fibre were studied. The swelling of these viscose fibres and the breaking length of hand sheets have been determined. Comparing the results, the influence of both, swelling and surface charge on the bonding force, is evident. The allocation of the charges, induced by cationic starch and Carboxmethylcellulose, has been analyzed by Titration, attenuated total reflection spectroscopy (ATR) and X-ray photoelectron spectroscopy (XPS). Titration was used to make a first estimation of the charge distribution within the fibre. Using ATR and XPS, more detailed information about the surface charge has been achieved. All measurement methods showed a significant amount of charge on the fibre surface. 相似文献
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Brecht Van Hooreweder David Moens Rene Boonen Jean-Pierre Kruth Paul Sas 《Polymer Testing》2013,32(5):972-981
This paper describes the influence of dynamic tension/compression loading on notched and unnotched nylon specimens fabricated by Injection Molding (IM) and Selective Laser Sintering (SLS). The main objective of this work is to analyze and describe the differences in material structure and fatigue properties of as-built nylon parts produced by IM and SLM from the same polyamide 12 powder. The differences in dimensional quality, density, surface roughness, crystal structure and crystallinity are systematically measured and linked to the mechanical fatigue properties. The fatigue properties of the unnotched SLS specimens are found to be equal to those of the unnotched IM specimens. The presence of pores in the sintered samples does not lead to rapid failure, and the microvoid coalescence failure mechanism is delayed. The notched specimens show more brittle failure and increased fatigue resistance which is caused by local notch-strengthening. The results enable improved understanding of the difference in material structure and fatigue behavior of selective laser sintered and injection molded polyamide. 相似文献
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ABSTRACT Synthesis of the terminal trisaccharide sequence of the ganglioside GD3, α-D-Neup5Ac-(2→8)-α-D-Neup5Ac-(2→3)-β-D-Galp-(1→4)-β-D-Glcp-(1→1)-Cer (2) was achieved by employing an α-(2→8) disialyl glycosyl donor (1). Condensation of 1 with the glycosyl acceptor 6, propyl 4,6-O-benzylidene-β-D-galactopyranoside, gave the desired protected trisaccharide 10 (14%) as well as the elimination and hydrolysis products of 6, compounds 8 and 9 respectively. O-Deacetylation and debenzylation of 10 gave the final trisaccharide 11, as its propyl glycoside. 相似文献
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Liquid-liquid(L-L)de-mixing and vitrification of solutions of either crystallizable poly(L-lactic acid)(PLLA)or non-crystallizable poly(D/L-lactic acid)(PDLLA)with 50 m%N,N-diethyl-3-methylbenzamide(DEET)were analyzed by calorimetry and cloud-point measurements,which allows drawing conclusions about the effect of polymer stereochemistry on the phase behavior.Regardless of the PLA stereochemistry,vitrification of the solutions on fast cooling,hindering crystallization of PLLA,occurred below-20℃ and suppressed prior L-L de-mixing.The experimental results prove that crystallization in samples containing crystallizable PLLA,observed at around 55℃ on slow cooling,is not preceded by L-L de-mixing. 相似文献
15.
Sebastian Gatz Helge Hannebauer Rene Hesse Florian Werner Arne Schmidt Thorsten Dullweber Jan Schmidt Karsten Bothe Rolf Brendel 《固体物理学:研究快报》2011,5(4):147-149
We demonstrate industrially feasible large‐area solar cells with passivated homogeneous emitter and rear achieving energy conversion efficiencies of up to 19.4% on 125 × 125 mm2 p‐type 2–3 Ω cm boron‐doped Czochralski silicon wafers. Front and rear metal contacts are fabricated by screen‐printing of silver and aluminum paste and firing in a conventional belt furnace. We implement two different dielectric rear surface passivation stacks: (i) a thermally grown silicon dioxide/silicon nitride stack and (ii) an atomic‐layer‐deposited aluminum oxide/silicon nitride stack. The dielectrics at the rear result in a decreased surface recombination velocity of Srear = 70 cm/s and 80 cm/s, and an increased internal IR reflectance of up to 91% corresponding to an improved Jsc of up to 38.9 mA/cm2 and Voc of up to 664 mV. We observe an increase in cell efficiency of 0.8% absolute for the cells compared to 18.6% efficient reference solar cells featuring a full‐area aluminum back surface field. To our knowledge, the energy conversion efficiency of 19.4% is the best value reported so far for large area screen‐printed solar cells. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
16.
Interactions between CdTe quantum dots and DNA revealed by capillary electrophoresis with laser‐induced fluorescence detection 下载免费PDF全文
Maja Stanisavljevic Jana Chomoucka Simona Dostalova Sona Krizkova Marketa Vaculovicova Vojtech Adam Rene Kizek 《Electrophoresis》2014,35(18):2587-2592
Quantum dots (QDs) are one of the most promising nanomaterials, due to their size‐dependent characteristics as well as easily controllable size during the synthesis process. They are promising label material and their interaction with biomolecules is of great interest for science. In this study, CdTe QDs were synthesized under optimal conditions for 2 nm size. Characterization and verification of QDs synthesis procedure were done by fluorimetric method and with CE. Afterwards, QDs interaction with chicken genomic DNA and 500 bpDNA fragment was observed employing CE‐LIF and gel electrophoresis. Performed interaction relies on possible matching between size of QDs and major groove of the DNA, which is approximately 2.1 nm. 相似文献
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