Most efforts to move past the limitations of traditional transistors have relied on the use of semiconducting materials. However, alternative materials like boron-nitride nanotubes (BNNTs) may be able to do the same thing through the phenomenon of quantum tunneling. Researchers in Michigan and at Oak Ridge National Laboratory have recently demonstrated precise control of electrons using quantum dot-equipped BNNTs.
Picture two light beams intersecting one another in space. When the beams touch one another, does the light bend? Reflect? Combine into a single beam? The answer, of course, is the light beams do nothing; they simply continue on their path. But in certain crystalline materials and with a powerful enough laser, it is possible to make photons interact with one another and take on a special set of characteristics.
Waste from textile and paint industries often contains organic dyes such as methylene blue as pollutants. Photocatalysis is an efficient means of reducing such pollution, and molybdenum trioxide catalyzes this degradation. Researchers in India now report four methods to produce nanosheets made of very few layers of molybdenum trioxide, which are more efficient than their bulk counterparts.
Electrolysis is often used to produce hydrogen that can be used for a storable fuel. Modified solar cells with highly efficient architecture can use this method to obtain hydrogen from water with the help of catalysts. But these solar cells rapidly corrode in aqueous electrolytes. By embedding the catalysts in an electrically conducting polymer, researchers have prevented this corrosion while maintaining competitive efficiency.
Scientists on Long Island are preparing to move a 50-foot-wide electromagnet 3,200 miles over land and sea to its new home at the U.S. Department of Energy's Fermi National Accelerator Laboratory in Illinois. The trip, starting at Brookhaven National Laboratory, is expected to take more than a month.
Researchers have made the first direct images of electrical currents flowing along the edges of a topological insulator. In these strange solid-state materials, currents flow only along the edges of a sample while avoiding the interior. Using an exquisitely sensitive detector they built, the team was able to sense the weak magnetic fields generated by the edge currents and tell exactly where the currents were flowing.
Taking a page from computer-aided drug designers, Rice Univ. researchers have developed a computational method that chemists can use to tailor the properties of zeolites, one of the world’s most-used industrial minerals. The method allows chemists to work backward by first considering the type of zeolite they want to make and then creating the organic template needed to produce it.
Researchers working to design new materials that are durable, lightweight and environmentally sustainable are increasingly looking to bone for inspiration. While researchers have come up with hierarchical structures in the design of new materials, going from a computer model to the production of physical artifacts has been a persistent challenge. Now researchers have developed an approach that allows them to turn their designs into reality.
Commonly found in many fruits, vegetables, coffees, teas, and wines, antioxidants are generally regarded as healthy chemicals. However, the problem with using antioxidants in other products is that many of these molecules are not actually very stable. Scientists have recently developed a nanomaterial that protects other molecules from oxidation, and unlike previous attempts the new antioxidant has a long shelf life.
Nanoscopic crystals of silicon assembled like skyscrapers on wafer-scale substrates are being intensely studied as a possible breakthrough in highly efficient battery technologies. A researcher at Northeastern University has been using computational to understand the atomic-scale interactions between the growth of nanowires and new development in this area of technology: alloyed metal droplets.
Colloidal solutions are made up of large particles, dispersed in a liquid solvent, that achieve stable structural arrangements through various types of self-assembly. But what about self-assembly of two—or more—species of different colloids? Scientists showed that when the interactions between the particles of two different DNA-coated colloids are carefully designed, they result in the formation of new structures.
Lawrence Livermore National Laboratory researchers, for the first time, have created movies of irreversible reactions that occur too rapidly to capture with conventional microscopy. The team used multiframe, nanosecond-scale imaging in the dynamic transmission electron microscope to create movies of the crystallization of phase-change materials used for optical and resistive memory.
Sandia National Laboratories researchers want airports, border checkpoints and others to detect homemade explosives made with hydrogen peroxide without nabbing people whose toothpaste happens to contain peroxide. That’s part of the challenge faced in developing a portable sensor to detect a common homemade explosive called a FOx mixture, made by mixing hydrogen peroxide with fuels.
Technology exists for removing heavy metals from drinking water, but often is too costly in developing countries. Scientists are now reporting the development of an inexpensive new material made of clay and papaya seeds removes harmful metals from water and could lower the cost of providing clean water to millions of people in the developing world.
Space scientists from the Univ. of New Hampshire and the Southwest Research Institute report that data gathered by NASA’s Lunar Reconnaissance Orbiter show lighter materials like plastics provide effective shielding against the radiation hazards faced by astronauts during extended space travel. The finding could help reduce health risks to humans on future missions into deep space.
Using foam substrates, researchers in Switzerland have made a flexible electronic circuit board. In experiments using various deformable materials, the team discovered a new kind of platform upon which to build circuits: elastomeric foams. These foams, used in packaging materials, serve as a substrate for metallic materials and can be stretched without disrupting electrical conductivity. The breakthrough could progress on electronic skin.
Rice Univ. researchers have for the first time detailed the molecular mechanism that makes a particular combination of cement and polymer glue so tough. The theoretical research led to a fine picture of how hydrogen bonds control the properties of hybrid organic-inorganic materials. The finding has implications for understanding the interface bonding that is often a roadblock to improved composite properties.
For more than a decade, scientists have suspected that hairpin-shaped chains of micro-RNA regulate wood formation inside plant cells. Now, scientists at North Carolina State Univ. have found the first example and mapped out key relationships that control the process. The research describes how one strand of micro-RNA reduced by more than 20% the formation of lignin, which gives wood its strength.
Scientists at Ames Laboratory have discovered a new family of rare-earth quasicrystals using an algorithm they developed to help pinpoint them. Quasicrystalline materials may be found close to crystalline phases that contain similar atomic motifs, called crystalline approximants. And just like fishing experts know how to hook a big catch, the scientists used their knowledge to hone in on the right spot for their discovery.
Catalysts can stop working when atoms on the surface of those materials start moving. At the Vienna University of Technology, this “dance” of the atoms has been observed and explained: A certain type of molecule initiates a clustering process, which causes the catalyst atoms, like palladium, to ball together and disappear from contact with the surrounding gas.
In the superconducting state, electrons travel in so-called Cooper pairs through the crystal lattice. An energy gap accounts for the difference in energy needed to break up these pairs into free electrons. In high-temperature superconductors, a similar energy gap also occurs above the superconducting transition temperature: the pseudogap. A German-French research team has constructed a new model that explains how this pseudogap state forms.
Silicon can accept ten times more lithium than the graphite used in the electrodes in lithium-ion batteries, but silicon also expands, shortening electrode life. Looking for an alternative to pure silicon, scientists in Germany have now synthesized a novel framework structure consisting of boron and silicon, which could serve as electrode material.
Based on the mathematics used to model the interaction of light with the atmospheres of giant gas planets, a new algorithm from the Institute of Physical Chemistry of the Polish Academy of Sciences in Warsaw offers a fast and accurate way to better understand physical and chemical properties of materials' surfaces.
A sensor that relies on reflected light to analyze biomedical and chemical samples now has greater sensitivity, thanks to a carpet of gold nanoparticles. Other researchers have shown that gold nanoparticles can enhance the responsiveness surface plasmon resonance sensors (SPR), which magnifies reflected light intensity. Scientists in Singapore have now determined the ideal size of nanoparticle to improve these SPR sensors.
Metamaterials have already been fabricated that have a negative refractive index for electromagnetic waves, but controlling shorter light waves has proved far more difficult. Researchers have now synthesized metamaterials based on organic molecules as building blocks. This approach has several advantages over the metallic nanostructures previously used.