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81.
Grigory Zinovyev Ivan Sumerskii Philipp Korntner Irina Sulaeva Thomas Rosenau 《木材化学与工艺学杂志》2017,37(3):171-183
Technical lignins are complex, irregular, polyphenolic compounds obtained in large quantities as by-products of the pulp and paper industries or according to current biorefinery setups. The availability of kraft lignin is increasing due to larger scale retrieval from process liquors, which opens new possibilities for further refining or new applications of such lignins. In the present study, sequential ultrafiltration of kraft lignin was performed to fractionate the lignin and to elucidate molar mass-dependent changes in lignin structure. Two industrial black liquors and three precipitated lignins were fractionated, and their functional groups were determined, providing molar mass-dependent profiles. Interrelations between structural parameters and functional groups, the molecular weight ranges, and the different lignin sources are discussed. This will help to establish structure-property-application relationships (SPARs) for technical lignins which are required for any future large-scale application. 相似文献
82.
Structure and conductivity of yttria and scandia‐doped zirconia crystals grown by skull melting 下载免费PDF全文
Mihail A. Borik Sergey I. Bredikhin Vladimir T. Bublik Aleksej V. Kulebyakin Irina E. Kuritsyna Elena E. Lomonova Philipp O. Milovich Valentina A. Myzina Vyacheslav V. Osiko Polina A. Ryabochkina Nataliya Y. Tabachkova 《Journal of the American Ceramic Society》2017,100(12):5536-5547
In this paper a detailed study of the (ZrO2)1‐x(Y2O3)x (x=0.025–0.15), (ZrO2)1‐x(Sc2O3)x (x = 0.06 – 0.11) and (ZrO2)1‐x‐y(Sc2O3)x(Y2O3)y (x=0.07 – 0.11; y=0.01 – 0.04) solid solution crystals grown by skull melting technique is presented. The structure, phase composition, and ion conductivity of the obtained crystals were investigated by X‐ray diffraction, transmission electron microscopy, Raman scattering spectroscopy, and impedance spectroscopy. Maximum conductivity as (ZrO2)1‐x(Y2O3)x and (ZrO2)1‐x(Sc2O3)x solid solution crystals is observed for the compositions containing 10 mol% stabilizing oxide, and the conductivity of 10ScSZ is ~3 times higher than for 10YSZ. Experiments on crystal growth (ZrO2)1‐x‐y(Sc2O3)x(Y2O3)y solid solutions showed that uniform, transparent crystals 7Sc3YSZ, 7Sc4YSZ, 8Sc2YSZ, 8Sc3YSZ, 9Sc2YSZ, 9Sc3YSZ, 10Sc1YSZ, and 10Sc2YSZ are single phase crystal containing t″ phase. It is established that a necessary condition of melt growth of (ZrO2)1‐x‐y(Sc2O3)x(Y2O3)y single‐phase crystals is the total concentration of the stabilizing oxides from 10 to 12 mol%. The addition of Y2O3 affects the (ZrO2)1‐x‐y(Sc2O3)x(Y2O3)y solid solution conductivity different ways and depends on the Sc2O3 content in the starting composition. The effects of structure, phase composition, concentration, and type of stabilizing oxides on the electrical characteristics of obtained crystals are discussed. 相似文献
83.
Alexander Shakhov Christian Reichenbach Daria Kondrashova Philipp Zeigermann Dirk Mehlhorn Prof. Dirk Enke Dr. Rustem Valiullin 《化学,工程师,技术》2013,85(11):1734-1741
Mesoporous glasses – the leaching products of phase‐separated alkali borosilicate glasses – are widely used in fundamental research and practical applications. In this work, the option to control their internal mesopore structure by varying the conditions of microphase separation has been studied. Structure and transport characterization of a family of nanoporous glasses obtained under different conditions has been performed using a combination of several experimental techniques, including gas adsorption, nuclear magnetic resonance cryoporometry and diffusometry. 相似文献
84.
Ulrich Müller Martine Philipp Jan Christoph Gaukler Wulff Possart Roland Sanctuary Jan Kristian Krüger 《The Journal of Adhesion》2013,89(3):253-276
The curing of an epoxy consisting of the solid hardener dicyandiamide (DICY) and the resin diglycidyl ether of bisphenol A (DGEBA) is studied in a system consisting of a tablet of DICY embedded in liquid DGEBA. Dissolution of DICY within the liquid DGEBA in combination with the transport of dissolved DICY from the tablet border into DGEBA and the chemical reaction of both reactants is studied by scanning Brillouin microscopy and infrared spectroscopy. Scanning Brillouin microscopy demonstrates the spatial and temporal evolution of the static and dynamic hypersonic properties in the course of curing in the vicinity of the DICY tablet. Infrared spectroscopy performed on epoxy pieces extracted from the final sample at different distances from the tablet surface give information about the spatial evolution of the curing process. The results achieved by both techniques are finally combined to yield a better understanding of the curing of DICY-based epoxies, which transform upon curing from strongly heterogeneous systems towards increasingly homogeneous systems. 相似文献
85.
Determining good parameter estimates in (exponential smooth transition autoregressive) models is known to be difficult. We show that the phenomena of getting strongly biased estimators is a consequence of the so‐called identification problem, the problem of properly distinguishing the transition function in relation to extreme parameter combinations. This happens in particular for either very small or very large values of the error term variance. Furthermore, we introduce a new alternative model – the TSTAR model – which has similar properties as the ESTAR model but reduces the effects of the identification problem. We also derive a linearity and a unit root test for this model. 相似文献
86.
A theoretical approach to the kinetics of the thermal decomposition of molten thermoplastic polyurethane elastomers, under conditions of thermoplastic processing, is described. On the basis of these considerations, the thermal decomposition in different instruments (melt index analyser and measuring extruder) can be described quantitatively and the various results can be compared. As a result, identical conditions of decomposition of the melt can be defined accurately, thus opening up the possibility of combining experimental values from different instruments. The fundamental kinetic equation obtained for the kinetics of the thermal decomposition of thermoplastic polyurethanes describes the decomposition reaction and the reverse reaction (formation reaction) – which is dependent on the system of measurement and processing – as a function of the molar mass (end‐group concentration) of the original product, determined from the velocity constants for the decomposition reaction and back reaction. The consideration of the limiting value for t → ∞ is in agreement with the equilibrium constant. Consequently, the development of physical characteristic functions of thermoplastic polyurethane elastomers – independent of the system of measurement – is possible.
87.
88.
Philipp Wolf Alexander Mohr Georgina Gavins Victoria Behr Karin Mörl Prof. Oliver Seitz Prof. Annette G. Beck-Sickinger 《Chembiochem : a European journal of chemical biology》2022,23(6):e202100340
Fine-tuning of G protein-coupled receptor (GPCR) signaling is important to maintain cellular homeostasis. Recent studies demonstrated that lateral GPCR interactions in the cell membrane can impact signaling profiles. Here, we report on a one-step labeling method of multiple membrane-embedded GPCRs. Based on short peptide tags, complementary probes transfer the cargo (e. g. a fluorescent dye) by an acyl transfer reaction with high spatial and temporal resolution within 5 min. We applied this approach to four receptors of the cardiovascular system: the endothelin receptor A and B (ETAR and ETBR), angiotensin II receptor type 1, and apelin. Wild type-like G protein activation after N-terminal modification was demonstrated for all receptor species. Using FRET-competent dyes, a constitutive proximity between hetero-receptors was limited to ETAR/ETBR. Further, we demonstrate, that ETAR expression regulates the signaling of co-expressed ETBR. Our orthogonal peptide-templated labeling of different GPCRs provides novel insight into the regulation of GPCR signaling. 相似文献
89.
A numerical procedure is presented which allows one to predict the deposition rate of microparticles suspended in a liquid flow onto the confining walls. Particle transport is not only diffusive but also affected by hydrodynamically induced lift force and reduced particle mobility. An appropriate expression for the lift‐induced migration is introduced into the numerical procedure. Its results agree quanititatively with previously published experimental data showing a significant effect of lift‐induced particle transport. Based on the numerical results algebraic correlations are obtained, which enable to calculate the particle deposition rate in situations where lift forces and mobility reduction diminishes the particle deposition rate. 相似文献
90.
Abstract. We show that tests for a break in the persistence of a time series in the classical I (0)/ I (1) framework have serious size distortions when the actual data-generating process (DGP) exhibits long-range dependencies. We prove that the limiting distribution of a CUSUM of squares-based test depends on the true memory parameter if the DGP exhibits long memory. We propose adjusted critical values for the test and give finite sample response curves that allow easy implementation of the test by the practitioner and also ease in computing the relevant critical values. We furthermore prove the consistency of the test for a simple breakpoint estimator also under long memory. We show that the test has satisfying power properties when the correct critical values are used. 相似文献