There are two guides from official GIMP website:
Simple Animations Learn how to work with GIMP’s layers as animation frames.
Advanced Animations Learn how to make an animation with GAP.

Carey Bunks wrote a very good free online book “Grokking the GIMP”, which detailedly described various tips for using GIMP, including a Chapter “Web Animations“.

You can also find a good article talking about “Using GIMP to make a simple animated GIF“, in the website of the University of Florida.

Use Google to search “gimp animation”, you can get enough information about using GIMP to create a animation.

Within the last few years, there has been a surge of interest in composite materials consisting of a polymer filled with platelike particles, such as clay particles. Such fillers are extremely effective in modifying the properties of polymers, and orders-of-magnitude improvements in transport, mechanical, and thermal properties have been reported. Examples of applications include low-permeability packaging for food and electronics, toughened automotive components, and heat and flame resistant materials. Polymer–clay nanocomposites have several unique features: First,they are lighter in weight than conventional filled polymers with the same mechanical performance. Second, their mechanical properties are potentially superior to fiber reinforced polymers because reinforcement from the inorganic layers occurs in two rather than one dimension. Third, they exhibit outstanding diffusional-barrier properties without requiring a multipolymer layered design, and thus can be recycled.Clays are colloidal suspensions of platelike mineral particles, with a large aspect ratio. Typically the particles are formed from silicate layers combined with layers of octahedrally coordinate aluminum or magnesium atoms. The layer structure leads to a lamellar phase for the clay in water. The aim in applications is to retain this structure in the polymer–clay nanocomposite, possible structures for which are illustrated schematically in Figure. Exfoliation and phase separation should be avoided and there is an immense literature (especially patent literature) on how to achieve this by chemical treatment of the clay particles (in particular adsorption of organic molecules). The intercalated structure leads to enhanced barrier properties, which result from the tortuous path for gas diffusion around the clay platelets.Liquid-crystal phases formed by mineral moieties have been known for almost as long as organic liquid crystals. Renewed interest in them has arisen because of the ability to combine the properties of liquid crystals, in particular anisotropy and fluidity, with the electronic and structural properties of minerals. They may also be cheaper to produce than conventional liquid crystals, which require organic synthesis. Rodlike mineral systems that form nematic phases have been well studied. Sheet-forming mineral compounds that form smectic (layered) structures in solution are also known.

1. I. W. Hamley, “Nanotechnology with soft materials,” ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 42, no. 15 (2003): 1692-1712.

Zotero [zoh-TAIR-oh] Zotero is a free, open source scholars’ extension for the Firefox browser, that enables users to collect, manage, and cite research from all types of sources from the browser. It is partly a piece of reference management software, used to manage bibliographies and references when writing essays and articles. More generally, it aims to be a “next-generation research tool” for students and researchers of all genres. On many major research websites such as digital libraries, Google Scholar, or even Amazon.com, Zotero senses when a book, article, or other resource is being viewed and with one mouse click it finds and saves the full reference information to a local reference library. If the source is an online article or web page, Zotero can optionally store a local copy of the source. Users can then add notes, tags, and their own metadata through the in-browser interface. Selections of the local reference library data can later be exported as formatted bibliographies for research papers or other purposes.

Zotero is produced by the Center for History and New Media of George Mason University and is currently available in public beta. The name is from Albanian language “to master”.

The Zotero model is aimed at replacing the model of traditional reference management software which, because it was originally designed to meet the demands of offline research, tends to make collecting citation information from online sources (as well as locating and accessing cited sources online and sharing bibliographies electronically) a cumbersome process for scholars, libraries and research sites.

Because Zotero is open and extensible, it allows other users to contribute citation styles and site translators, and more generally for others who are building digital tools for researchers to expand the platform.

CiteULike is a social bookmarking service for academics. Instead of letting users catalog web pages (like Furl or del.icio.us) or photographs (like Flickr) it specialises in academic papers, and provides specific tools for that purpose.

Specifically, users can post academic articles using a bookmarklet and the system will attempt to determine the article metadata (title, authors, journal name, etc) automatically. Users can organize their libraries with freely chosen tags which has the side-effect of producing a folksonomy of academic interests.

Connotea is a free online reference management service for scientists, researchers, and clinicians, created in December 2004 by Nature Publishing Group. It is one of a new breed of social bookmarking tools, similar to CiteULike and del.icio.us, where users can save links to their favourite websites.

Unlike many of the other well-known tools, Connotea is aimed primarily at scientists (though the user community is rapidly growing throughout academic disciplines), and while users may bookmark any webpage they choose, it incorporates special functionality for certain academic resources. Connotea recognises a number of scientific websites and will automatically collect metadata for the article or page being bookmarked, including author and publication names. It is also possible to add non-recognised webpages, by manually entering information. An alternative method of adding an article is to retrieve the Connotea form and add the Digital Object Identifier (DOI) for the article. Information about the material should then be retrieved automatically using CrossRef, the official DOI registration point. This function means that it is possible to quickly retrieve the reference for a print article that has an electronic counterpart with a DOI.

When saving an article to Connotea, users “tag” the article with keywords of their choice which they can later use to find it again. By categorising articles with relevant keywords e.g. “C. elegans”, the social aspect of Connotea is developed. The system recognises users who are bookmarking the same papers or using the same keywords, and alerts them to potentially related material. Allowing completely free tagging, a folksonomy will gradually develop. By default, links posted to Connotea are publicly viewable, allowing network effects to build up rapidly, but it also possible for users to keep selected links private, either indefinitely or until a specified date and time. Connotea also provides RSS feeds, allowing users to keep track of articles posted under interesting tags or by users with similar interests.

One of the most useful features of Connotea is the capacity to export the references in RIS format to a citation manager program. This means that it is possible to save references when working on a computer without such bibliographic software installed and import them into this software for citing at later stage.

Use of the service is entirely free, and the source code for Connotea has been released as open-source software.

In September 2005, Connotea won the Association of Learned and Professional Society Publishers (ALPSP) Award for Publishing Innovation, and in November 2005 was shortlisted for the International Information Industry awards in the Best Scientific, Technical and Medical (STM) Product category.