Combinatorial techniques, parallel experimentation and high‐throughput methods represent a very promising approach in order to speed up the preparation and investigation of new polymeric materials: a large variety of parameters can be screened simultaneously resulting in new structure/property relationships. The field of polymer research seems to be perfectly suited for parallel and combinatorial methods due to the fact that many parameters can be varied during synthesis, processing, blending as well as compounding. In addition, numerous important parameters have to be investigated, such as molecular weight, polydispersity, viscosity, hardness, stiffness and other application‐specific properties. A number of corresponding high‐throughput techniques have been developed in the last few years and their introduction into the commercial market further boosted the development. These combinatorial approaches can reduce the time‐to‐market for new polymeric materials drastically compared to traditional approaches and allow a much more detailed understanding of polymers from the macroscopic to the nanoscopic scale. Here we provide an overview of the present status of combinatorial and parallel polymer synthesis and high‐throughput screening.
This paper investigates the influences of higher order viscoelasticity and the inhomogeneities of the transversely isotropic elastic parameters on the disturbances in an infinite medium, caused by the presence of a transient radial force or twist on the surface of a cylindrical hole with circular cross section. Following Voigt's model for higher order viscoelasticity, the nonvanishing stress components valid for a transversely isotropic and higher order viscoelastic solid medium have been deduced in terms of radial displacement component. Considering the power law variation of elastic and viscoelastic parameters, the stress equation of motion has been developed. Solving this equation under suitable boundary conditions, due to transient forces and twists, radial displacement and relevant stress components have been determined in terms of modified Bessel functions. The problem for the presence of transient radial force has been numerically analysed. Modulations of displacement and stresses due to different order of viscoelasticity and inhomogeneity have been graphically depicted. The numerical study of the disturbance caused by the presence of twist on the surface may be similarly done but is not pursued in this paper. 相似文献
A soft X-ray laser-plasma source, used in radiobiology experiments with yeast cells, was characterised with flat crystal spectrometers
and P-I-N diodes, obtaining an absolute measurement of the emission spectrum. A comparison with the results of simulations
performed with the code RATION allowed the characterisation of the emitting plasma. A model for the energy deposition in yeast
cells was developed to take into account the different cell structures (wall-membrane complex, cytoplasm and nucleus). Dose
calculations performed considering the source emission spectrum were compared with direct measurements of transmission through
plastic foils and allowed to verify the hypothesis of preferential dose deposition in the outer cellular regions.
Received 16 September 1999 and Received in final form 1st February 2000 相似文献