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141.
142.
Adriana Valentina Busuioc Dragoş Iftimie 《Journal of Dynamics and Differential Equations》2006,18(2):357-379
We consider in this paper the equations of motion of third grade fluids on a bounded domain of
or
with Navier boundary conditions. Under the assumption that the initial data belong to the Sobolev space H
2, we prove the existence of a global weak solution. In dimension two, the uniqueness of such solutions is proven. Additional regularity of bidimensional initial data is shown to imply the same additional regularity for the solution. No smallness condition on the data is assumed. 相似文献
143.
Roy M. Pemberton Frankie J. Rawson Jinsheng Xu Robin Pittson Guido A. Drago John Griffiths Simon K. Jackson John P. Hart 《Mikrochimica acta》2010,170(3-4):321-330
Microband biosensors were fabricated from a screen-printed water-based carbon ink containing cobalt phthalocyanine redox mediator and glucose oxidase or lactate oxidase enzyme. The microbiosensors were characterised for their ability to monitor ferrocyanide and H2O2 in phosphate buffer solution: sigmoidal cyclic voltammograms, high current density values and steady-state amperometric responses confirmed the existence of radial-diffusion-limiting microelectrode behaviour. The lactate microband biosensors were then used, in conjunction with a screen-printed Ag/AgCl reference and platinum counter electrode, to monitor lactate levels in culture medium, with a linear range of 0.5–5 mM, sensitivity of 20 nA.mM?1, and dynamic range up to >9 mM. The lactate microband biosensors could operate continuously in culture medium over extended times (up to 24 h) at 37 °C. These biosensors were then applied to detect changes in lactate release from cultured cells in response to toxic challenge: m-dinitrobenzene (500 μM) caused a reduction in lactate production by high-passage number HepG2 single cells; D-galactosamine (20 mM) induced release of lactate by HepG2 spheroid cultures. This novel use of microband biosensors in cell culture has the potential for further application in toxicity monitoring, in both environmental and pharmaceutical areas. 相似文献
144.
Optimal operation of a chemical reactor according to various performance criteria often drives the system towards critical
boundaries. Thus, precise evaluation of runaway limits in the parametric space becomes a crucial problem not only for the
reactor’s safe operation, but also for over-designing the system. However, obtaining an accurate estimate for operating limits
is a difficult task due to the limited validity of kinetic models describing complex processes, as well as the inherent fluctuations
of the system’s properties (catalyst, raw-material quality). This paper presents a comparison of several effective methods
of deriving critical conditions for the case of a tubular fixed-bed catalytic reactor used for aniline production in the vapour
phase. Even though the methods being compared are related to one another, the generalised sensitivity criterion of Morbidelli-Varma
(MV) seems to be more robust, not depending on a particular parameter being perturbed, when compared to the criteria that
detect an incipient loss of system stability in the critical region (i.e., div-methods based on the system’s Jacobian and
Green’s function matrix analysis). Combined application of div- and MV criteria allows for an accurate evaluation of the distance
from the reactor’s nominal conditions to the safety limits. 相似文献