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1.
Cellulose - The shear modulus of pulp fibers is difficult to measure and only very little literature is available on this topic. In this work we are introducing a method to measure this fiber... 相似文献
2.
Matthew Hirn 《Linear algebra and its applications》2010,432(5):1105-1125
Harmonic frames of prime order are investigated. The primary focus is the enumeration of inequivalent harmonic frames, with the exact number given by a recursive formula. The key to this result is a one-to-one correspondence developed between inequivalent harmonic frames and the orbits of a particular set. Secondarily, the symmetry group of prime order harmonic frames is shown to contain a subgroup consisting of a diagonal matrix as well as a permutation matrix, each of which is dependent on the particular harmonic frame in question. 相似文献
3.
Wolfgang J. Fischer Armin Zankel Christian Ganser Franz J. Schmied Hartmuth Schroettner Ulrich Hirn Christian Teichert Wolfgang Bauer Robert Schennach 《Cellulose (London, England)》2014,21(1):251-260
Besides the determination of the force and the energy needed to break individual fibre to fibre joints, the investigation of the formerly bonded area (FBA) is of essential importance to learn more about the failure mechanisms of fibre–fibre bonds in general. In this study the surfaces of paper fibres and the FBA of fibre–fibre joints after the determination of the breaking force as well as the bonding energy were analysed by means of low voltage scanning electron microscopy and atomic force microscopy. A comparison between the contact zone of fibres broken at different loading rates as well as under cyclic loading showed that there seems to be no significant difference in the appearance of the FBA in these cases. Only minor delamination of the cell wall could be found in the bonding zone, which indicates no mechanical interlocking of fibrils in the bonding zone. Furthermore, it is shown that some glues used for specimen preparation of fibre–fibre bond strength measurement are forming a glue film on the fiber surface and migrate into the bonding region. 相似文献
4.
Cellulose - Wet wipe dispersibility is broadly discussed since they have been detected in massive fatbergs that were found in sewer systems of big cities, e.g., London. Dispersibility describes a... 相似文献
5.
Franz J. Schmied Christian Teichert Lisbeth Kappel Ulrich Hirn Robert Schennach 《Cellulose (London, England)》2012,19(3):1013-1021
A method is presented which enables analysis of lignin precipitated on the surface of kraft pulp fibers. As experimental input,
high-resolution atomic force microscopy phase images of the fiber surfaces have been recorded in tapping mode. A digital image
analysis procedure—based on the watershed algorithm—is applied to distinguish between cellulose fibrils and the precipitated
lignin. In this way, size distributions for the diameter of lignin precipitates on pulp fiber surfaces can be obtained. In
an initial application of the method, three softwood kraft pulps were analyzed: a black liquor cook with a very high content
of precipitated lignin, a bleached pulp where nearly no precipitated lignin is visible and an unbleached industrial pulp.
The proposed method is suggested as an appropriate tool to investigate the kinetics of lignin precipitation and the structure
of lignin precipitates in pulping and bleaching. 相似文献
6.
Distribution of water-soluble and surface-active low-molecular-weight species in acrylic latex films 总被引:1,自引:0,他引:1
Belaroui F Hirn MP Grohens Y Marie P Holl Y 《Journal of colloid and interface science》2003,261(2):336-348
Monodisperse core-shell latices were synthesized, differing in the acrylic acid (AA) content in the particle shell (1 or 4 wt%) and the Tg of the acrylic core (around -40 or 10 degrees C). In a first step, the drying mechanisms of the dialyzed latices were studied by confocal Raman spectroscopy. It was shown that, besides some unexpected features (briefly described in the article), drying occurred in a rather classical way, i.e., simultaneously from top to bottom and from edge to center. Then, the distributions of sulfate ion (SO4) (from sodium sulfate) and sodium dodecyl sulfate (SDS) in the dry latex films were established by confocal Raman spectroscopy and attenuated total reflectance (ATR). The two techniques were complementary. SO4 and SDS distributions were quite different, although presenting some common characteristics. In both cases, repartition of the low-molecular-weight species in the film was even less homogeneous when the AA content was lower and the particle core softer. However, SO4 showed enrichment at the film-substrate interface and depletion at the air side, whereas SDS showed concentration maxima at both interfaces. Interpretations stress the importance of desorption from the particle-water interface, transport by water, size effects, and diffusion. 相似文献
7.
Inspired by recent developments of moose models, we reconsider low-energy effective theories of Goldstone bosons, gauge fields and chiral fermions applied to low-energy QCD and to Higgs-less electroweak symmetry breaking. Couplings and the corresponding reduction of symmetry are introduced via constraints enforced by a set of non-propagating covariantly constant spurion fields. Relics of the latter are used as small expansion parameters conjointly with the usual low-energy expansion. Certain couplings can only appear at higher orders of the spurion expansion and, consequently, they become naturally suppressed independently of the idea of dimensional deconstruction. At leading order this leads to a set of generalized Weinberg sum rules and to the suppression of non-standard couplings to fermions in Higgs-less EWSB models with the minimal particle content. Within the latter, higher spurion terms allow for a fermion mass matrix with the standard CKM structure and C P violation. In addition, Majorana masses for neutrinos are possible. Examples of non-minimal models are briefly mentioned.Received: 8 January 2004, Revised: 7 February 2004, Published online: 2 April 2004 相似文献
8.
E. Gilli A. E. Horvath A. T. Horvath U. Hirn R. Schennach 《Cellulose (London, England)》2009,16(5):825-832
Infrared spectroscopy has been used to measure the amount of carboxymethyl cellulose (CMC) attached to cellulosic fibers.
CMC was attached to an unbleached kraft pulp in aqueous conditions. Isotropic handsheets were then prepared and ATR spectroscopy
was used to measure the intensity of the carboxyl vibration, which correlates to the amount of attached CMC that was determined
using a wet chemical approach. The ATR method is rather time consuming as several measurement points on the sample have to
be averaged, although it is still much faster than the wet chemical approach. Infrared reflection absorption spectroscopy
(IRRAS) using polarized light was further used to measure the amount of attached CMC. In this method the intensity of an electromagnetic
wave confined to the thin layer is used to correlate the spectroscopy to the amount of CMC on the fiber surface in the paper
sample. The measurement time is shorter than with the ATR method. The proposed IRRAS method could be employed as a fast and
reliable way to quantify adsorption of chemicals on pulp fibers. 相似文献
9.
We present a new class of 5D models, Holographic Technicolor, which fulfills the basic requirements for a candidate of comprehensible 4D strong dynamics at the electroweak scale. It is the first Technicolor-like model able to provide a vanishing or even negative tree-level S parameter, avoiding any no-go theorem on its sign. The model is described in the large-N regime. S is therefore computable: possible corrections coming from boundary terms follow the 1/N suppression, and generation of fermion masses and the S parameter issue do split up. We investigate the model's 4D dual, probably walking Technicolor-like with a large anomalous dimension. 相似文献
10.
Matthew J. Hirn 《Proceedings of the American Mathematical Society》2008,136(3):899-908
Refinable functions have been widely investigated because of their importance in wavelet theory and multiresolution analysis, as well as because of intrinsic interest. Problems involving refinability can be challenging and interesting problems in mathematics. Several papers have investigated refinability of splines and other classes of functions. The purpose of this paper is to develop necessary and sufficient conditions for the refinability of the class of step functions on the real line taking complex values.