An international research team has engineered a potentially important new class of nanostructured materials for microwave and advanced communication devices. According to the National Institute of Standards and Technology, the multilayer crystal materials are so-called “tunable dielectrics”—materials that have proved difficult to make for the frequency range used by cell phones and other modern communications. Consisting of layers of strontium oxide and strontium titanate, the new materials (shown in the transmission electron micrograph above; credit: D. Mueller and N. Orloff/NIST) are said to consume less power than previous generations of tunable dielectric and work well at frequencies to 100 GHz.
Using the European Synchrotron (ESRF) X-ray source, scientists have shown that electrons absorbed and released by cerium dioxide nanoparticles during chemical reactions behave in a completely different way than previously thought. According to researchers from ESRF and Universitá Autònoma of Barcelona, Catalan Institute of Nanotechnologies, the electrons are not bound to individual atoms but distributed like a cloud over the entire nanoparticle. The scientists call this spatial distribution an “electron sponge.” They are already working to assess whether the non-localized electrons are unique to CeO2 or also can be produced using other common nanoparticles such as titanium dioxide.
Common clay, a seemingly infertile blend of minerals, might have been the birthplace of life on Earth, according to scientists at Cornell University. The researchers discovered that clay mixed with simulated ancient seawater produced a hydrogel that confined biomolecules and biochemical reactions. Over millions of years, the confined chemicals could have undergone the complex reactions that formed proteins, DNA, and, eventually, all the chemicals needed to make living cells work. The scientists also demonstrated protein synthesis in a synthetic clay hydrogel.
Researchers at Washington State University say they have achieved a 400-fold increase in the electrical conductivity of a strontium titanate crystal simply by exposing it to light. They say the effect, which lasted for days, could dramatically improve the performance of future electronic devices. Scientists chanced upon the discovery when they noticed a sample of strontium titanate became conductive after it was left out in the lab one day. The room-temperature persistent photoconductivity phenomenon could one day lead to large increases in information storage capacity via holographic memory, scientists say.
Federal-Mogul Corp.’s Powertrain Segment has developed an automated casting process it says will produce stronger, more wear-resistant piston rings for automotive engines. The process uses a vertical molding technique to provide higher quality and improved process control. The company says thinner piston rings that fit more tightly in cylinders are vital to continued vehicle emissions reductions, but this required a stronger ring material. Federal Mogul’s automated vertical casting process lets engineers optimize design of blanks and gating systems, improving material flow control during casting and producing grey cast iron rings with better structural uniformity than the previous horizontal casting process.