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111.
We report viscometric data collected in a Couette rheometry on dilute, single‐solvent polystyrene (PS)/dioctyl phthalate (DOP) solutions over a variety of polymer molecular weights (5.5 × 105 ≤ Mw ≤ 3.0 × 106 Da) and system temperatures (288 K ≤ T ≤ 318 K). In view of the essential viscometric features, the current data may be classified into three categories: The first concerns all the investigated solutions at low shear rates, where the solution properties are found to agree excellently with the Zimm model predictions. The second includes all sample solutions, except for high‐molecular‐weight PS samples (Mw ≥ 2.0 × 106 Da), where excellent time–temperature superposition is observed for the steady‐state polymer viscosity at constant polymer molecular weights. No similar superposition applies at a constant temperature but varied polymer molecular weights, however. The third appears to be characteristic of dilute high‐molecular‐weight polymer solutions, for which the effects of temperature on the viscosity curve are further complicated at high shear rates. The implications concerning the relative importance of hydrodynamic interactions, segmental interactions, and chain extensibility with increasing polymer molecular weight, system temperature, and shear rate are discussed. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 787–794, 2006 相似文献
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113.
F. D. Saccone C. E. Rodrí guez Torres F. H. S nchez O. Gutfleisch 《Physica B: Condensed Matter》2002,320(1-4):312-315
In the present work, a quantitative analysis of the phase compositions by Mössbauer effect spectroscopy of solid and conventional hydrogen disproportionated Pr13.7Fe80.3B6.0 and Pr13.7Fe63.5Co16.7Zr0.1B6.0 alloys was carried out. Significant amounts of intermediate borides t-Fe3B and Pr(Fe, Co)12B6 were detected after solid hydrogen disproportionation treatment in Pr13.7Fe80.3B6.0 and Pr13.7Fe63.5Co16.7Zr0.1B6.0 alloys, respectively. After conventional hydrogenation–disproportionation–desorption–recombination treatment these phases were not detected and in no case residual Pr2Fe14B-phase was found. It was observed that the amount of intermediate borides after disproportionation can be correlated with the degree of texture after recombination at various temperatures. 相似文献
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116.
Xinjian Yi Sihai Chen Yingrui Wang Bifeng Xiong Hongchen Wang 《International Journal of Infrared and Millimeter Waves》2002,23(12):1699-1704
V02-based thin film materials on silicon substrates are fabricated by ion beam sputtering and a post-annealing which is different from the conventional fabricating method. An infrared linear microbolometer array with 128 pixels is prepared using as-deposited vanadium dioxide thin films. Optical and electrical properties for V02-based microbolometer array are tested. 相似文献
117.
V. T. Plaksiy O. N. Suchoruchko B. P. Yefimov A. P. Kasyanenko 《International Journal of Infrared and Millimeter Waves》2002,23(4):645-650
Bismuth, antimony and its alloys are the typical representatives of a class of semimetals, which electric conductance is lower in 102-103 times, than of usual well conducting an electrical current metals. The alloys bismuth with antimony have semi-conductor properties in wide area of compositions at temperatures below 77 °K. The semimetals are rather perspective materials from the point of view of their probable application in various devices [1,2,3].In present time the semimetal alloys BiSb have wide application in thermoelectric generators and refrigerators. In work [3] the opportunity of use of semimetals BiSb with percentage content of Bi and Sb from 8 % up to 25 % was shown as high-sensitivity and of small inertion indicators of the mm range radiation where thermoelectric effect is used. The principle of action of such indicators is based on occurrence of temperature gradient in a semimetal crystal BiSb that has two contacts of the various area with flowing electrical current. Basic element of such device is the dot contact metal - semimetal. One of the main characteristics is volt-watt sensitivity of metal-semimetal BiSb contact which calculating is shown in present work. 相似文献
118.
The paper presents an analytical study of blood flow through a stenosed artery using a suitable mathematical model. The artery is modelled as an anisotropic viscoelastic cylindrical tube containing a non-Newtonian viscous incompressible fluid representing blood. The blood flow is assumed to be characterized by the Herschel–Bulkley model. The effect of the surrounding connective tissues on the motion of the arterial wall has been incorporated. Initially, the relevant solutions of the boundary value problem are obtained in the Laplace transform space, through the use of a suitable finite difference technique. Laplace inversion is carried out by employing suitable numerical techniques. Finally, the variations of the vascular wall displacements, the velocity distribution of the blood flow, the flux, the resistance to flow and the wall shear stress in the stenotic region are quantified through numerical computations and presented graphically. 相似文献
119.
Summary Cold neutrons at the external neutron guide laboratory (ELLA) of the KFA Jülich are used to demonstrate their profitable application
for multielement characterization of biological materials. The set-up and experimental conditions of the Prompt Gamma Cold
Neutron Activation Analysis (PGCNAA) device is described in detail. Results for C, H, N, S, K, B, and Cd using synthetic standards
and the “ratio” technique for calculation are reported for several reference materials and prove the method to be reliable
and complementary with respect to the elements being determined by INAA.
IAEA fellow at the KFA from 6. 3. 91 to 2. 9. 91 on contract No. VIE/9016R. 相似文献
120.