Moisissure

Résumé

Une moisissure est un . Par exemple : les Oomycota (oomycètes) chez les Chromista (voir image ci-dessous à droite). Caractéristiques communes Les moisissures sont avant tout connues pour leur effet d’altération des aliments, par exemple du pain et des fruits. Dans la chaîne alimentaire, les moisissures sont des décomposeurs naturels. La prolifération des moisissures dépend des conditions suivantes :

la présence de spores de moisissures (qui sont toujours présentes à l’intérieur d'un bâtiment et à l’extérieur) ;
une température appropriée, variant entre 2 et (voire plus) ;
une source d’alimentation, c’est-à-dire tout ce qui est organique : fruits et légumes, autres aliments, livres, tapis, vêtements, bois, plâtre, enduit de colle organique ;
une source d’humidité.

Principaux genres Moisissure, hygiène et santé thumb|upright|alt= Moisissure gris-bleu, d'aspect velouté, dans les cavités d'un fromage blanc-ivoire.|Penicillium roqueforti sur

Source officielle

https://fr.wikipedia.org/wiki/Moisissure

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Easy release fluoropolymer molds for micro- and nano-pattern replication

David Barbero, Hans Jörg Mathieu

A mold (35) for use in nano- or micro-replication processes on thermoplastic polymer substrates (20), comprises a nano- or micro-structured fluoropolymer surface that, when the mold (35) is used in a nano- or micro-replication process, serves for the application of a nano- or micro-structuration on a thermoplastic polymer substrate (20,22). The nano- or micro-structured fluoropolymer surface is itself obtained by nano- or micro-structuration against the fluoropolymer surface (30) using a master mold (10) of silicon, quartz, nickel, steel, copper, or another material of comparable properties having a nano- or micro-structuration corresponding to that to be applied to a substrate (22). The fluoromold (35) can be used for nano- or micro-imprint lithography, or a liquid polymer can be coated or extruded against the nano-or micro-structured fluoropolymer surface.

2006

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Multilevel Micro-Structuring of Glassy Carbon Molds for Precision Glass Molding

Hans Peter Herzig, Karin Prater, Toralf Scharf

Replication techniques for diffractive optical elements (DOEs) in soft materials such as plastic injection molding are state of the art. For precision glass molding in glasses with high transition temperatures, molds with extreme thermal resistivity, low chemical reactivity and high mechanical strength are needed. Glassy Carbon can be operated up to 2000 degrees C making it possible to mold almost all glasses including Fused Silica with a transition temperatures above 1060 degrees C. For the structuring of Glassy Carbon wafers photolithography and a RIE process is used. We have developed a process using Si as a hard mask material. If the flow rates of the etching gases O-2 and SF6 are chosen properly, high selectivity of GC to Si 19:1 can be achieved, which provides excellent conditions to realize high resolution elements with feature size down to 1 micron and fulfills requirements for optical applications. We fabricated several multilevel GC molds with 8 levels of structuring. Two different optical functionalities were implemented: 6x6 array beamsplitter and 1x4 linear beamsplitter. The molds were applied for precision glass molding of a low Tg glass L-BAL 42 (from Ohara) with a transition temperature of 565 degrees C. Their optical performance was measured. A more detailed analysis of the impact of mold fabrication defects on optical performance is done. Rigorous coupled wave analysis simulations are performed, where we included fabrication constrains such as duty cycle, edge depth errors, wall verticality and misalignment errors. We will compare the results with the design specifications and discuss the influence of fabrication errors introduced during the different process steps.

Spie-Int Soc Optical Engineering2015

Chargement

, ,

The demand of high resolution diffractive optical elements (DOE) is growing. Smaller critical dimensions allow higher deflection angles and can fulfill more demanding requirements, which can only be met by using electron-beam lithography. Replication techniques are more economical, since the high cost of the master can be distributed among a larger number of replicas. The lack of a suitable mold material for precision glass molding has so far prevented an industrial use. Glassy Carbon (GC) offers a high mechanical strength and high thermal strength. No anti-adhesion coatings are required in molding processes. This is clearly an advantage for high resolution, high aspect ratio microstructures, where a coating with a thickness between 10 nm and 200 nm would cause a noticeable rounding of the features. Electron-beam lithography was used to fabricate GC molds with highest precision and feature sizes from 250 nm to 2 mu m. The master stamps were used for precision glass molding of a low T-g glass L-BAL42 from OHARA. The profile of the replicated glass is compared to the mold with the help of SEM images. This allows discussion of the max. aspect-ratio and min. feature size. To characterize optical performances, beamsplitting elements are fabricated and their characteristics were investigated, which are in excellent agreement to theory.

Spie-Int Soc Optical Engineering2016

Chargement