法国视角下的创意城市

自20世纪90年代中期以来,创意城市的概念已经逐渐介入法国城市区域治理和发展的相关讨论中.这种介入也出现在推崇地域性文化特色的论文中.本文有双重目的:首先,基于国际上已出现的大量文献,剖析创意城市的概念;其次,通过里昂、里尔和圣艾蒂安三个中等规模城市中的一系列案例研究,对出现的不同观点进行阐释.     

Initial Attatchment of rMSC and MG‐63 Cells on Patterned Bioglass® Substrates

A soft lithography technique was used to introduce surface patterns on the surface of sintered bioactive glass substrates. Osteoblast‐like MG‐63 cells and rat mesenchymal stem cells (rMSC) seeded on micropatterned bioactive glass surfaces showed different behavior with rMSC exhibiting a better initial attachment than MG‐63 cells. Both cytoskeleton formation and cell spreading of rMSC were supported by the bioactive surfaces. In addition, the structured surfaces seemed to guide MG‐63 cells to a larger extent than rMSC. The in vitro results are important considering the continuous development of bone tissue scaffolds based on silicate bioactive glasses.     

A combination of capillary and dielectrophoresis-driven assembly methods for wafer scale integration of carbon-nanotube-based nanocarpets

The wafer scale integration of carbon nanotubes (CNT) remains a challenge for electronic and electromechanical applications. We propose a novel CNT integration process relying on the combination of controlled capillary assembly and buried electrode dielectrophoresis (DEP). This process enables us to monitor the precise spatial localization of a high density of CNTs and their alignment in a pre-defined direction. Large arrays of independent and low resistivity (4.4 × 10(-5) Ω m) interconnections were achieved using this hybrid assembly with double-walled carbon nanotubes (DWNT). Finally, arrays of suspended individual CNT carpets are realized and we demonstrate their potential use as functional devices by monitoring their resonance frequencies (ranging between 1.7 and 10.5 MHz) using a Fabry-Perot interferometer.     

Effect of Green-State Processing on the Sintering Stress and Viscosity of Alumina Compacts

Uniaxial viscosity and sintering stress of pressure filtrated alumina compacts were evaluated from sinter-forging measurements. At a particular density, significantly higher values of sintering stresses are observed compared with specimens made by uniaxial dry pressing followed by cold isostatic pressing. In addition, the uniaxial viscosity at a given density is lower for the pressure-filtrated samples. These differences may be explained by a more homogeneous microstructure and finer pore size and emphasize the importance of green density and packing on the evolution of the constitutive parameters for crystalline materials.     

Study of whispering gallery modes in anisotropic single-crystaldielectric resonators

The Rayleigh-Ritz method and the finite element method nongenerating spurious solutions are employed for analysis of whispering gallery modes (WGMs) in cylindrical single-crystal anisotropic dielectric resonators. These methods allow accurate computation of the resonant frequencies, the Q-factors (depending on the dielectric and on the conductor losses), and the electromagnetic field distributions for all WGMs in the presence of additional elements like metal shields, MIC substrate, or supports. Different families of modes are studied both theoretically and experimentally. The mode coupling phenomenon is investigated. A WGM single-crystal quartz resonator is presented having an unloaded Q-factor greater than 30000 at about 100 GHz, including radiation and dielectric losses     

Analysis and realization of L-band dielectric resonatormicrowave filters

High power L-band dielectric resonator microwave filters, used in satellite systems because of their good temperature and vibration characteristics, low weight, and size, are discussed. The electromagnetic and electrical parameters of different microwave dielectric resonator structures are computed by means of the two-dimensional and three-dimensional finite element method, which are applied both for free and forced oscillation systems. The design and response evaluation of an elliptic filter using rectangular dielectric resonators excited in their TM₁₁₀ mode are presented     

External occulter laboratory demonstrator for the forthcoming formation flying coronagraphs

The design and optimization of the external occulter geometry is one of the most discussed topics among solar coronagraph designers. To improve the performance of future coronagraphs and to stretch their inner fields of view toward the solar limb, the new concept of coronagraphs in formation flight has been introduced in the scientific debate. Solar coronagraphs in formation flight require several mechanical and technological constraints to be met, mainly due to the large dimension of the occulter and to the spacecraft's reciprocal alignment. The occulter edge requires special attention to minimize diffraction while being compatible with the handling and integrating of large delicate space components. Moreover, it is practically impossible to set up a full-scale model for laboratory tests. This article describes the design and laboratory tests on a demonstrator for a coronagraph to be operated in formation flight. The demonstrator is based on the principle of the linear edge, thus the presented results cannot be directly extrapolated to the case of the flying circular occulter. Nevertheless, we are able to confirm the results of other authors investigating on smaller coronagraphs and provide further information on the geometry and tolerances of the optimization system. The described work is one of the results of the ESA STARTIGER program on formation flying coronagraphs ["The STARTIGER's demonstrators: toward a new generation of formation flying solar coronagraphs," in 2010 International Conference on Space Optics (ICSO) (2010), paper 39].