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81.
D. Sternik P. Staszczuk J. Pękalska G. Grodzicka B. Gawdzik J. Osypiuk-Tomasik P. Witer 《Journal of Thermal Analysis and Calorimetry》2006,86(1):85-91
The adsorption of a polar (water)
and a non-polar (n-octane) liquid on silica
gels, modified by adsorption of proteins, has been studied by thermal analysis.
Silica gels with physically adsorbed BSA and ovalbumin layers were used. Thermodesorption
energies were determined from Q-TG and Q-DTG curves recorded under quasi-equilibrium
conditions. Significant differences in liquid desorption were observed from
the surfaces due to heterogeneous changes (energetic and geometrical) as a
result of modification. These results are compared with those obtained for
the samples heated at 160°C for 1 h. 相似文献
82.
P. Staszczuk D. Sternik G. W. Chądzyński E. Robens M. Błachnio 《Journal of Thermal Analysis and Calorimetry》2006,86(1):133-136
Nitrogen
adsorption measured at 77 K was used to characterize the surface heterogeneity
of high-temperature superconductor surfaces. Properties relating to adsorption
and porosity of the solids (adsorption capacity, specific surface area, radii
and volume of the pores, pore-size distribution function) were determined
from nitrogen adsorption–desorption isotherms and atomic force microscopy
(AFM) for a series of oxide superconductors. It is shown that the adsorption
isotherms of all samples are S-shaped and belong to type II according to the
IUPAC classification. On the basis of the nitrogen adsorption isotherms and
AFM data, fractal dimensions were determined and correlations found with adsorption
and porosity parameters. 相似文献
83.
粗糙表面分维计算的立方体覆盖法 总被引:16,自引:0,他引:16
针对三角形棱柱表面积法和投影覆盖法在计算粗糙表面分形维数中存在的问题,提出了计算粗糙表面分维的立方体覆盖法,对计算结果进行了对比分析,并进一步对表面分维计算中的有关理论问题进行了分析,发现立方体覆盖法作为一种几何意义上的覆盖法,并计算结果比三角形棱柱表面积法和投影覆盖法更接近实际。 相似文献
84.
Hitting probabilities and the Hausdorff dimension of the inverse images of a class of anisotropic random fields 下载免费PDF全文
Let X = {X(t):t ∈ R~N} be an anisotropic random field with values in R~d.Under certain conditions on X,we establish upper and lower bounds on the hitting probabilities of X in terms of respectively Hausdorff measure and Bessel-Riesz capacity.We also obtain the Hausdorff dimension of its inverse image,and the Hausdorff and packing dimensions of its level sets.These results are applicable to non-linear solutions of stochastic heat equations driven by a white in time and spatially homogeneous Gaussian noise and anisotropic Guassian random fields. 相似文献
85.
周云华 《数学物理学报(B辑英文版)》2013,(5):1375-1381
In this paper, we define robust weak ergodicity and study the relation between robust weak ergodicity and stable ergodicity for conservative partially hyperbolic systems. We prove that a Cr(r > 1) cons... 相似文献
86.
87.
88.
C. Connell McCluskey 《Journal of Mathematical Analysis and Applications》2008,338(1):518-535
A very general compartmental model of the spread of an infectious disease with mass action incidence is given. The global stability of this system is completely determined using Lyapunov functions. The general system exhibits the traditional threshold behaviour. The dimension of the system is arbitrary, allowing, in particular, for detailed modelling of the distribution of latency times for tuberculosis. 相似文献
89.
We consider ordinary differential equations (ODEs) with a known Lyapunov function V. To ensure that a numerical integrator reflects the correct dynamical behaviour of the system, the numerical integrator should
have V as a discrete Lyapunov function. Only second-order geometric integrators of this type are known for arbitrary Lyapunov functions.
In this paper we describe projection-based methods of arbitrary order that preserve any given Lyapunov function.
AMS subject classification (2000) 65L05, 65L06, 65L20, 65P40 相似文献
90.
A highly nonnormal Jacobian may give rise to large transients. This behaviour has been shown to have implications for (a) the relevance of linearising a nonlinear system and (b) the timestep restrictions required to keep a numerical method stable. Here, we show that nonnormality also manifests itself for stochastic differential equations. We give an example of a family of systems that is stable without noise, but can be made exponentially unstable in mean-square by a noise perturbation that shrinks to zero as the nonnormality increases. We then show via finite-time convergence theory that an Euler approximation shares the same property, giving a discrete analogue of the result. In memory of Germund Dahlquist (1925–2005).AMS subject classification (2000) 65C30, 34F05 相似文献