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排序方式: 共有105条查询结果,搜索用时 15 毫秒
1.
Johan Sjöblom Camilla Dagsgård Sébastien Simon Geir Sørland Morten Hana 《Journal of Dispersion Science and Technology》2017,38(2):206-215
The present study reports on the influence of partially hydrolyzed polyacrylamide (HPAM) on essential w/o emulsion properties. The characterization has been undertaken with low field NMR to follow droplet sizes and distributions, sedimentation and coalescence kinetic, bench-scale electrocoalescence (Ecrit) experiments to follow emulsion stability changes, and electrorheology to detect changes in the viscosity upon applying an external electric field. The result is that HPAM does not basically influence the droplet size distribution (DSD) and the stability level of the emulsions as can be expected of bulk polymers. However, there seems to be an interaction between added demulsifiers either through direct molecular interaction or via an interfacial complexation. 相似文献
2.
The Butcher group is a powerful tool to analyse integration methods for ordinary differential equations, in particular Runge–Kutta methods. In the present paper, we complement the algebraic treatment of the Butcher group with a natural infinite-dimensional Lie group structure. This structure turns the Butcher group into a real analytic Baker–Campbell–Hausdorff Lie group modelled on a Fréchet space. In addition, the Butcher group is a regular Lie group in the sense of Milnor and contains the subgroup of symplectic tree maps as a closed Lie subgroup. Finally, we also compute the Lie algebra of the Butcher group and discuss its relation to the Lie algebra associated with the Butcher group by Connes and Kreimer. 相似文献
3.
4.
Henrik Høyer Matti Knaapila Jakob Kjelstrup‐Hansen Xuhai Liu Geir Helgesen 《Journal of Polymer Science.Polymer Physics》2012,50(7):477-483
We demonstrate micromechanical strain sensors with integrated readout based on carbon nanocones and discs (CNCs) which are aligned into a string‐like formation using an alternating electric field and studied by AC impedance spectroscopy and electromechanical methods. The CNC particles are first dispersed into a polymer matrix with a particle fraction of 0.1 vol %. This value is well below the percolation threshold (~ 2 vol %), which suppresses particle aggregation and facilitates transparency allowing the use of an UV‐curable polymer. Alignment was carried out with a 1 kHz, 4 kV/cm electric field and is a consequence of dielectrophoretic effect. It develops in minutes and makes the initially insulating, nonaligned material conductive. This is followed by UV curing of the polymer matrix, which renders a solid state device. The stretching of the aligned strings in the cured polymer leads to a reversible piezoresistive effect, and a gauge factor of about 50 is observed. This is in a sharp contrast to CNC films with particle fraction above percolation threshold (13 vol %), which are conductive but not sensitive to stretching. The strings are Ohmic in nature and moreover show higher DC conductivity (22–500 S/m) compared to identically prepared carbon black strings (1–22 S/m). © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011 相似文献
5.
Deokki Min Nils Hoivik Geir Uri Jensen Frode Tyholdt Camilla Haavik Ulrik Hanke 《Applied Physics A: Materials Science & Processing》2011,105(4):867-874
The dielectric properties of zirconium dioxide (ZrO2) ceramic thin films were characterized up to 50 GHz using coplanar waveguides (CPWs) and metal–insulator–metal (MIM) capacitors
with top circular electrodes. The ZrO2 films were deposited using a chemical solution onto high-resistivity Si wafers and metal layers. The real part of the dielectric
constant of approximately 22 and 26 was extracted at 50 GHz for CPW and MIM structures, respectively, and the loss tangent
was approximately 0.09 at 50 GHz. C–V and I–V measurements were carried out to determine low-frequency and DC dielectric properties. The measurement results indicate that
ZrO2 is a promising material to be used as a dielectric layer for radio-frequency (RF) microelectromechanical systems (MEMS) capacitive
switches. 相似文献
6.
The ultimate product of the clinical laboratory is not a number, but an advice. To what quality standards should this advice live up to? In external quality assurance for primary health care in Norway, case histories are mailed together with the analytical quality control material. The analytical result of the control material is used in the case history. The feedback reports discuss clinical guidelines as well as the influence of analytical variation on clinical decision-making. 相似文献
7.
Sans résuméEspace projectif sur un corps algébriquement clos de caractéristique zéro 相似文献
8.
Geir Dahl 《Linear algebra and its applications》2009,430(8-9):2457-2463
9.
Geir Dahl 《Linear algebra and its applications》2008,429(7):1840-1850
We consider some questions concerning transportation matrices with a certain nonzero pattern. For a given staircase pattern we characterize those row sum vectors R and column sum vectors S such that the corresponding class of transportation matrices with the given row and column sums and the given pattern is nonempty. Two versions of this problem are considered. Algorithms for finding matrices in these matrix classes are introduced and, finally, a connection to the notion of majorization is discussed. 相似文献
10.
Wetting Phase Bridges Establish Capillary Continuity Across Open Fractures and Increase Oil Recovery in Mixed-Wet Fractured Chalk 总被引:1,自引:0,他引:1
Eirik Aspenes Geir Ersland Arne Graue Jim Stevens Bernard A. Baldwin 《Transport in Porous Media》2008,74(1):35-47
The effect of fractures on oil recovery and in situ saturation development in fractured chalk has been determined at near
neutral wettability conditions. Fluid saturation development was monitored both in the matrix and in the fractures and the
mechanisms of fracture crossing were determined using high spatial resolution MRI. Capillary continuity across open oil-filled
fractures was verified by imaging the water bridges established within the fracture. Despite an alternate escape fracture
for the water, separate water bridges were shown to be stable for the entire duration of the experiments. The established
capillary contact resulted in oil recovery exceeding the spontaneous imbibition potential in the outlet-isolated cores by
ca. 10% PV. This is explained by viscous recovery provided by water bridges across open fractures. The size of the bridges
seemed to be controlled by the wettability of the rock and not by the differential pressure applied across the open fracture. 相似文献