Thin films of porphyrin molecules imaged with the atomic force microscope

The assembly of two-dimensional molecular structures of zinc porphyrin molecules arising from the dewetting of a porphyrin solution on mica and graphite is investigated using atomic force microscopy. Both a near equilibrium nucleation and growth process, and a far from equilibrium spinodal dewetting process are observed. Nucleation and growth around pre-existing surface defects on mica produces single layer disks, ∼ 10 μm in diameter, of densely packed molecules. Spinodal dewetting gives rise to the formation of much smaller, single layer, molecular islands of various sizes on both mica and graphite.     

Direct measurement of total emissivities at cryogenic temperatures: Application to satellite coatings

This paper presents a direct measurement method for optical properties of different materials at cryogenic temperatures from 20 K to 200 K. It has been developed within the framework of the design of Planck program. Planck is a satellite of the European Space Agency (ESA) that will be launched in 2008. The scientific goal of the Planck mission is to make observations of the temperature anisotropy and polarisation of the Cosmic Microwave Background. The equivalent temperature of the observed radiation is about 3 K and the telescope baffle temperature should not exceed 60 K in order to work properly. The large Planck telescope is passively cooled by radiating to the Deep Space, so that a good knowledge of the thermo-optical properties of its coating is of utmost importance for thermal modelling. However, up to now, few measurements have been done at such low temperatures. We derived a direct measurement method for the total directional emissivity of various coatings of interest for satellites applications. The effective spectral range chosen the measurements covers 6–800 μm. We will describe the design of the measurement apparatus and present results for several coatings.     

Some recent results in structured robust stability: An overview

Some recent results on robust stability with structured perturbations, using the polynomial framework, are presented in this paper without proof. As background we first describe Kharitonov's theorem and give an interpretation of it as a generalization of the Hermite—Bieler interlacing theorem. The need for a generalization of this result for tackling the control problem is explained, and our new results are then presented. An important generalization of Kharitonov's theorem that solves the box problem in parameter space is described. Some efficient formulae for the l²-stability margin in parameter space are also given. The results are illustrated by examples.     

Lightwave single sideband wavelength self-tunable filter using anInP:Fe crystal for fiber-wireless systems

A new optical single sideband filter is presented to compensate for chromatic dispersion effects in fiber-wireless systems. The device is based on three dynamic Bragg gratings, which are generated in a photorefractive iron-doped indium phosphide (InP:Fe) crystal. This filter is controlled by the input optical double sideband signal itself, which makes it independent of the modulated optical carrier wavelength. In this paper, the principle of the device is presented and demonstrated. Experiments include a 14-km fiber transmission followed by a 3-m radio link carrying a 140-Mb/s binary phase-shift keyed data stream at 16 GHz     

Highly conformal electrodeposition of copolymer electrolytes into titania nanotubes for 3D Li-ion batteries

ABSTRACT: It is reported the highly conformal electrodeposition of a copolymer electrolyte (PMMA-PEO) into self-organized titania nanotubes (TiO2nt). The morphological analysis carried out by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) evidenced the formation of a 3D nanostructure consisting of a copolymer-embedded TiO2nt. The thickness of the copolymer layer can be accurately controlled by monitoring electropolymerization parameters. X-ray photoelectron spectroscopy measurements confirmed that LiTFSI salt was successfully incorporated into the copolymer electrolyte during the deposition process. These results are crucial to fabricate a 3D Li-ion power source at the micrometer scale using TiO2nt as the negative electrode.     

An order-N complexity meshless algorithm for transport-type PDEs,based on local Hermitian interpolation

This work describes a new numerical method utilising radial basis function interpolants. Based on local Hermitian interpolation of function values and boundary operators, and using an explicit time advancement formulation, the method is of order-N complexity. Computational cost to advance the solution in time is minimal, and is largely dependent on local system support size. The explicit time advancement formulation allows a novel solution technique for many nonlinear partial differential equations.The performance of the method is examined for a variety of linear convection–diffusion–reaction problems, featuring both steady and unsteady solutions. The method is also demonstrated with a nonlinear Richards’ equation model, solving an unsaturated flow in porous media problem. The technique is named the local Hermitian interpolation (LHI) method.     

汽车本地网络的机电一体化解决方案

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