Convergence rates to nonlinear diffusion waves for weak entropy solutions to<Emphasis Type="Italic">p</Emphasis>-system with damping

This paper studies the asymptotic behavior of weak entropy solutions to the Cauchy problem of the so-called p-system with damping. The convergence rates to nonlinear diffusion waves for weak entropy solutions are obtained in L∞norm or L² -norm. These convergence rates are the same to the decay rates of smooth solution obtained by Nishihara. They are proved by using the vanishing viscosity method and the elementary L²-energy method.     

Metric character of Hamilton-Jacobi equations

We deal with the metrics related to Hamilton-Jacobi equations of eikonal type. If no convexity conditions are assumed on the Hamiltonian, these metrics are expressed by an - formula involving certain level sets of the Hamiltonian. In the case where these level sets are star-shaped with respect to 0, we study the induced length metric and show that it coincides with the Finsler metric related to a suitable convexification of the equation.

     

Homogenization in L

Homogenization of deterministic control problems with L^∞ running cost is studied by viscosity solutions techniques. It is proved that the value function of an L^∞ problem in a medium with a periodic micro-structure converges uniformly on the compact sets to the value function of the homogenized problem as the period shrinks to 0. Our main convergence result extends that of Ishii (Stochastic Analysis, control, optimization and applications, pp. 305-324, Birkhäuser Boston, Boston, MA, 1999.) to the case of a discontinuous Hamiltonian. The cell problem is solved, but, as non-uniqueness occurs, the effective Hamiltonian must be selected in a careful way. The paper also provides a representation formula for the effective Hamiltonian and gives illustrations to calculus of variations, averaging and one-dimensional problems.     

Fluorescence Probes for Cyclodextrin Interiors

6-Propionyl-2-(dimethylamino)naphthalene (PRODAN) emits two fluorescence bands, at 510 and 435 run, when dissolved in -cyclodextrin (CD) aqueous solutions. The relative contributions of these two bands were found to depend on time and temperature. These emissions are attributed to the inclusion of PRODAN with the dimethylamino group toward the larger and smaller rims inside the -CD cavities, respectively. The first position corresponds to a slightly polar and slightly rigid environment, while the second corresponds to a hydrophobic and rigid environment relative to the aqueous polar bulk. In contrast, PRODAN in either -CD or -CD aqueous solutions emits a single fluorescence band at 525 and 510 nm, respectively. The emission of PRODAN in -CD is similar to that in water and indicates no inclusion at all. In -CD, only one kind of inclusion is possible with the dimethylamino group of PRODAN toward the larger rims of -cavities. These results are supported by fluorescence decay lifetime measurements and are consistent with our previous observations made for 4-dimethylaminobenzonitrile (DMABN) and 4-diethylaminobenzonitrile (DEABN) in - and -CD aqueous solutions [23,24]. Therefore the possibility of twisted intramolecular charge transfer (TICT) state formation in PRODAN in terms of environmental polarity and local free volume of CD cavities is discussed. These observations put PRODAN, DMABN, and other TICT compounds as fluorescence probes for CD interiors.     

聚(丙烯酰胺-丙烯酸高级酯)的溶液性质研究

采用沉淀聚合法分别合成了丙烯酰胺与丙烯酸十四酯、丙烯酸十六酯、丙烯酸十八酯一系列疏水缔合型共聚物。对共聚物溶液性质及疏水基团浓度、电解质浓度、温度等因素对共聚物溶液性能的影响进行了研究,结果表明这类疏水缔合型聚合物表观出较好的耐温、耐盐等性能。     

The potential of field spectroscopy for the assessment of sediment properties in river floodplains

Investigations have shown that visible-near-infrared (VNIR) spectroscopy can accurately determine soil properties under laboratory conditions. In situ assessment of soil properties is of great benefit for several applications, as spectra can be acquired fast and almost continuously. The present study used partial least squares (PLS) regression to establish a relationship between soil reflectance spectra measured under field conditions and the organic matter and clay content of the soil. Spectra were acquired with a fieldspectrometer in a recently reconstructed floodplain along the river Rhine in The Netherlands. Several spectral pre-processing methods were employed to improve the performance and robustness of the models. Results indicate that, under varying surface conditions, field spectroscopy in combination with multivariate calibration does result in a qualitative relation for organic matter (R²=0.45) and clay content (R²=0.43) while under laboratory conditions more accurate results are obtained (R²=0.69 and 0.92, respectively). Soil moisture and vegetation cover had a negative influence on the prediction capabilities for both soil properties. Although the performance of the spectra measured in situ is not as accurate as physical analysis, the accuracy obtained is useful for rapid soil characterisation and remote sensing applications.     

The evaluation of miscibility of blends of poly(ether imide) (Ultem1000) and a copolyester of bisphenol-A with terephthalic and isophthalic acid (ArdelD-100) by viscosimetry

The intermolecular interactions and miscibility behavior between poly(ether imide) (Ultem^®1000) and a copolyester of bisphenol-A with a mixture of terephthalic and isophthalic acid (Ardel^®D-100) in compositions of 100/0, 80/20, 60/40, 40/60, 20/80 and 0/100 have been investigated in dilute solutions in chloroform. An Ubbelohde-type home-made viscometer was used to determine the specific viscosities of the blends in a constant temperature bath. Several viscosity interaction parameters used as the criteria of miscibility were determined from viscosity measurements. The parameters suggested that Ultem^®1000 and Ardel^®D-100 were miscible. The miscibility of the polymers was confirmed by the results of differential scanning calorimetry measurements.     

An efficient data compression method for the Davidson subspace diagonalization scheme

Summary A flexible and efficient compression scheme for the expansion and product vectors Hamiltonian matrix times expansion vectors is presented within the Davidson diagonalization method. Our approach is based on an error analysis of the energy in terms of the aforementioned vectors and on a compression scheme for representing floating point numbers with a variable length mantissa. For a selection of typical quantum chemical test cases total saving factors of up to ten are reported. The method is expected to work especially well for extended multi-reference CI and full CI cases. As a general outcome of our analysis we obtain limits of possible sizes of a CI expansion within the Davidson procedure in relation to the energy and the desired accuracy of the energy assuming the usual IEEE floating point standard.     

The Interaction between Collagen and an Aluminum Tanning Agent

The interaction between collagen and organometallic aluminum complexes was studied. From the analysis of the IR and UV spectra, the viscosity of collagen, and the treated collagen, a possible interaction model of the collagen with the aluminum tanning agent has been found. It indicates that such an aluminum tanning agent could be used as a cleaner tanning agent in leather tanning.

Viscosity curves of the untreated collagen solution (a) and the collagen solution treated with aluminum tanning agent (b).     

Genetic algorithms (GA) applied to the orthogonal projection approach (OPA) for variable selection

Multivariate curve resolution (MCR) and especially the orthogonal projection approach (OPA) can be applied to spectroscopic data and were proved to be suitable for process monitoring. To improve the quality of the on-line monitoring of batch processes, it is interesting to get as many as possible spectra in a given period of time. Nevertheless, hardware limitations could lead to the fact that it is not possible to acquire more than a certain number of spectra in this given period of time. Wavelength selection could be a good way to limit this problem since it decreases size, and consequently the acquisition time, of each recorded spectrum. This paper details an industrial application of genetic algorithms (GA) coupled with a curve resolution method (OPA) for such purpose.