Russian researchers produce crystals of various colors and shades based on yttrium, aluminium and oxygen. Outwardly, they practically do not differ from well-known semiprecious garnet stones. However, artificially produced crystals possess higher solidity, and the color variety is much wider than that of their natural “relatives”.
Sometimes a minor thing is sufficient to change the situation beyond recognition. That is particularly important in chemistry, especially in chemistry of crystals. A crystal is like a huge building constructed from atom “bricks”: in case of one redundant atom or vice versa – and the building changes the shape, the quality of such structure decreasing. To color the crystal building, small amounts (hundredth parts) of certain metals (color promoters) are required. Such admixtures of chromium and iron make the first-class gems – rubies and sapphires – from aluminium oxide.
Nature spends several years to achieve the result, however the laboratories need one or two days to produce the same. Laboratories also grow natural garnets, but the quality has to be sacrificed to the speed. Crystals of a large size (in this case, they are convenient for the jewellers art) can be grown up from the melt containing silicon o?ide, aluminium oxide, ferric oxide. Yttrium-aluminium garnets without admixtures are colorless. By adding different rare-earth metals in the course of preparing these crystals, not only the desired color can be ensured to clystals, but also the required shade. The advantage of these crystals is also that the color promoters are better distributed in them, therefore, producing the crystals of uniform color and high degree of purity.
Sergey Komarov | alfa
Watching atoms move in hybrid perovskite crystals reveals clues to improving solar cells
22.11.2017 | University of California - San Diego
Fine felted nanotubes: CAU research team develops new composite material made of carbon nanotubes
22.11.2017 | Christian-Albrechts-Universität zu Kiel
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
23.11.2017 | Information Technology
23.11.2017 | Physics and Astronomy
23.11.2017 | Life Sciences