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751.
Izabel Caldeira Andressa Lüdtke Fabiele Tavares Camila Cholant Raphael Balboni Wladimir H. Flores Alexandre Galio Agnieszka Pawlicka César O. Avellaneda 《Ionics》2018,24(2):413-420
Two water-soluble and biodegradable polymers: xanthan gum (XG) and poly(vinyl alcohol) (PVA) were used to synthesize ecologically friendly solid polymer electrolyte (SPE) matrices. While XG is a natural polymer, PVA is a synthetic one, but both are colorless and form transparent membranes. To obtain ionic conductivity properties, the samples were doped with acetic acid and characterized by electrochemical impedance spectroscopy (EIS), X-ray diffraction, UV-Vis spectroscopy, and tensile test. The best results of ionic conductivity of 1.97 × 10?4 and 7.41 × 10?4 S/cm at room temperature and 80 °C, respectively, were obtained for the sample containing 55 wt% of acetic acid. Moreover, this electrolyte was found to be predominantly amorphous with transmittance in the visible region of 80% and absorbance values below 0.5 between 240 and 375 nm. Tensile test of this sample, applied up to 18 N of maximum force, resulted in strain of 2322% and Young’s modulus of 0.02 MPa. The obtained results showed that these new eco-friendly materials are promising for use as electrolytes in electrochemical devices. 相似文献
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Raphael?ZinggEmail authorView authors OrcID profile Marius?Fischer 《Journal of nanoparticle research》2018,20(10):267
Despite all predictions and promises, nanotechnology still seems to be more of an emerging science than a fully fledged revolution. More often than not, the patent system is blamed for this, supposedly tangling up nanotechnology in an impenetrable thicket of exclusionary rights instead of setting it free. Drawing on methods of complex network analysis, we provide empirical evidence suggesting that, at least in Europe, there is actually no patent thicket present in nanotechnology. Yet, the situation appears to be different in the USA. 相似文献
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Bernadette Brady Raphael Darcy John F. O'sullivan 《Journal of inclusion phenomena and macrocyclic chemistry》1999,33(1):39-46
The twin-cavity cyclodextrin (1) in which the link is a dithiotrehalosyl unit, and the flexibly-linked dimer (2) were shown to distinguish between the heterocyclic guests 3 and 4 (clofazimine drug) in spite of the guests' small structural difference. Both cyclodextrin dimer hosts form 1:1 complexes with methyl orange and with 3, as shown by double reciprocal plots of UV-absorbance change and host concentration. However with 4, both host molecules formed a 2 : 1 (host : guest) complex . Since both dimer cavities are used to create this effect, it is a new type of selectivity for macrocyclic hosts. 相似文献
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Let G be a bipartite graph, with k|e(G). The zero-sum bipartite Ramsey number B(G, Zk) is the smallest integer t such that in every Zk-coloring of the edges of Kt,t, there is a zero-sum mod k copy of G in Kt,t. In this article we give the first proof that determines B(G, Z2) for all possible bipartite graphs G. In fact, we prove a much more general result from which B(G, Z2) can be deduced: Let G be a (not necessarily connected) bipartite graph, which can be embedded in Kn,n, and let F be a field. A function f : E(Kn,n) → F is called G-stable if every copy of G in Kn,n has the same weight (the weight of a copy is the sum of the values of f on its edges). The set of all G-stable functions, denoted by U(G, Kn,n, F) is a linear space, which is called the Kn,n uniformity space of G over F. We determine U(G, Kn,n, F) and its dimension, for all G, n and F. Utilizing this result in the case F = Z2, we can compute B(G, Z2), for all bipartite graphs G. © 1998 John Wiley & Sons, Inc. J. Graph Theory 29: 151–166, 1998 相似文献
757.
Raphael Paul Abdellah Khodja Andreas Fischer Karl Heinz Hoffmann 《Entropy (Basel, Switzerland)》2021,23(12)
Vuilleumier refrigerators are a special type of heat-driven cooling machines. Essentially, they operate by using heat from a hot bath to pump heat from a cold bath to an environment at intermediate temperatures. In addition, some external energy in the form of electricity can be used as an auxiliary driving mechanism. Such refrigerators are, for example, advantageous in situations where waste heat is available and cooling power is needed. Here, the question of how the performance of Vuilleumier refrigerators can be improved is addressed with a particular focus on the piston motion and thus the thermodynamic cycle of the refrigerator. In order to obtain a quantitative estimate of the possible cooling power gain, a special class of piston movements (the AS motion class explained below) is used, which was already used successfully in the context of Stirling engines. We find improvements of the cooling power of more than 15%. 相似文献
758.
Christopher J. Foust Richard R. Mills Thomas Haas Charles Castevens Raphael M. Ottenbrite 《Macromolecular Symposia》1997,123(1):1-8
We have developed a cellulose-polyethylene blend polymer film for degradative susceptibility to brown rot or cellulasic fungi. Paxon low-density polyethylene (LDPE) polymer pellets were melt-blended with 8855 cellulose. A pure polyethylene sample was melted, pressed and used as the control. Naturally occurring fungi were harvested from decaying wood and cultured on full nutrient agar until individual phenotypes developed. The discrete fungal colonies were isolated and transferred to bacteriological agar with carboxymethylcellulose as the only carbon source. Surviving fungi were subjected to an indirect cellulase assay to confirm cellulolytic properties. Trichoderma viride showed 100% surface area growth on low-density polyethylene (LDPE) blended with 8% (w/w) cellulose in 90 days. Growth coverage by Gliomastix on LDPE blended with 8% cellulose reached 100 % in 150 days, and up to 72% growth activity on blends with 1.5% cellulose, 1% cellulose, and the control LDPE. 相似文献
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The behaviour of flexible hydrosoluble polymers of high molecular weight: polyacrylamide and two polyacids, poly(α, L-glutamic acid) and a copolymer of maleic acid was investigated in the context of their dynamic behaviour at solid/liquid interfaces. The adsorption rate is related to the structure of the surface in terms of remaining interacting surface sites. The desorption rate was measured by carrying out adsorption with radioactive labelled polymers, followed by exchange with unlabelled polymers. The slow exchange rate observed suggests a metastable equilibrium state owing to strong multisegment adsorption in the potential well of the surface. However, the “diffuse” polymer layer formed by loops which extend in the aqueous phase within distances of several hundred Angstroms “responds” reversibly to a change in the solvent composition. The latter effect was found by recording the hydrodynamic permeability of pores covered by the adsorbed polymer; the permeability to fluid flow is very sensitive to the loop layer thickness. 相似文献