Hanchen Huang, an engineer at Northeastern Univ., has spent the last 10 years revising the classical theory of crystal growth that accounts for his observations of nanorod crystals. The theory, on the macroscale, holds that height steps gradually disappear as atoms of a given material tumble down to fill in the gaps. On the nanoscale, Huang has found, things operate differently.
Flexible, layered materials textured with nanoscale wrinkles could provide a new way of controlling the wavelengths and distribution of waves, whether of sound or light. The new method could eventually find applications from nondestructive testing of materials to sound suppression, and could also provide new insights into soft biological systems and possibly lead to new diagnostic tools.
Silicon-based electronics have physical limits that slow and may eventually halt the miniaturization of electronic devices. One of the possible solutions is to use molecules as circuits, but their poor conduction capabilities make them unlikely candidates. Researchers in Italy says, however, that the Kondo effect, in which molecules behave like magnetic impurities, could offer a solution.
You’ve probably seen it in your kitchen cookware, or inside old plumbing pipes: scaly deposits left over time by hard, mineral-laden water. It happens not only in pipes and cooking pots in the home, but also in pipelines and valves that deliver oil and gas, and pipes that carry cooling water inside power plants. Scale, as these deposits are known, causes inefficiencies, downtime and maintenance issues.
Sometimes solving a problem doesn’t require a high-tech solution. Sometimes, you have to look no farther than your desktop. Three students from Northwestern Univ.’s McCormick School of Engineering have proven that pencils and regular office paper can be used to create functional devices that can measure strain and detect hazardous chemical vapors.
Researchers in Ireland and Germany have discovered a novel solid state reaction which lets kesterite grains grow within a few seconds and at relatively low temperatures. The work points towards a new pathway for the fabrication of thin microcrystalline semiconductor films without the need of expensive vacuum technology.
In only a few years, the efficiency of perovskite-based solar cells has increased from 3% to more than 16%. However, a detailed explanation of the mechanisms of operation within this photovoltaic system is still lacking. in recent work, scientists have now uncovered the mechanism by which these novel light-absorbing semiconductors transfer electrons along their surface.
Researchers in California have created tactile sensors from composite films of carbon nanotubes and silver nanoparticles similar to the highly sensitive whiskers of cats and rats. These new e-whiskers respond to pressure as slight as a single Pascal, about the pressure exerted on a table surface by a dollar bill.
Superconducting quantum interference devices (SQUIDs) are incredibly sensitive magnetic flux sensors which have been limited in their applications because of thermal challenges at ultralow temperatures. Researchers in the U.K. have succeeded in overcoming this difficulty by introducing a new type of nanoscale SQUID based on optimized proximity effect bilayers.
Turbine manufacturers have employed special nickel-based high-performance “superalloys” for decades as a way to guarantee turbines maintain their chemical and mechanical properties almost to their melting point. New research shows in detail how new phases in a nickel-based alloy form and evolve during heat treatment, providing clues to how these high-performance alloys could be improved.
Scientists at Ames Laboratory have demonstrated broadband terahertz (THz) wave generation using metamaterials. The discovery may help develop noninvasive imaging and sensing, and make possible THz-speed information communication, processing and storage.
Solid catalysts based on precious metals, such as palladium, are widely used in industry to promote a range of chemical reactions. Finding ways to minimize the consumption of expensive catalytic materials, however, remains a critical challenge. Researchers in Japan have now developed a nanostructured catalyst that makes extremely efficient use of trace amounts of catalytic palladium.
Using the interaction between light and charge fluctuations in metal nanostuctures called plasmons, a Univ. of Arkansas physicist and his collaborators have demonstrated the capability of measuring temperature changes in very small 3-D regions of space. In the experiments the team fabricated plasmonic nanostructures with electron beam lithography and precisely focused a laser on to a gold nanowire with a scanning optical setup.
A collaboration of researchers has discovered that sodium bismuthate can exist as a form of quantum matter called a 3-D topological Dirac semi-metal (3DTDS). This is the first experimental confirmation of 3-D Dirac fermions in the interior or bulk of a material, a novel state that was only recently proposed by theorists. It is a natural counterpart because of its magnetoresistive properties.
Researchers at the Univ. of Delaware have developed a “smart” hydrogel that can deliver medicine on demand, in response to mechanical force. Over the past few decades, smart hydrogels have been created that respond to pH, temperature, DNA, light and other stimuli.
Using an approach akin to assembling a club sandwich at the nanoscale, NIST researchers have succeeded in crafting a uniform, multi-walled carbon nanotube-based coating that greatly reduces the flammability of foam commonly used in upholstered furniture and other soft furnishings. The flammability of the nanotube-coated polyurethane foam was reduced 35% compared with untreated foam.
“The interface is the device,” Nobel laureate Herbert Kroemer famously observed, referring to the remarkable properties to be found at the junctures where layers of different materials meet. In today’s burgeoning world of nanotechnology, the interfaces between layers of metal oxides are becoming increasingly prominent. Realizing the vast potential of these metal oxide interfaces requires detailed knowledge of their electronic structure.
For decades, increasing amounts of data have been successfully stored on media with ever-higher densities. Now, an international team has discovered a physical phenomenon that could prove suitable for use in further data aggregation. Researchers found that domain walls, which separate areas in certain crystalline materials, display a polarization, potentially allowing information to be stored in the tiniest of spaces.
A team at the Laboratory for Attosecond Physics in Germany has constructed a detector which provides a detailed picture of the waveforms of femtosecond laser pulses. Knowledge of the exact waveform of these pulses enables scientists to reproducibly generate light flashes that are a thousand times shorter, just attoseconds, and can be used to study ultrafast processes at the molecular and atomic levels.
A new development by researchers at the Univ. of California, Berkeley, could lead to curtains and other materials that move in response to light, no batteries needed. Engineers have created a new light-reactive material made up of carbon nanotubes and plastic polycarbonate.
A new fabrication method inspired by blown sugar art has been used to make structure in which an ultrathin graphene layer, or layers, is glued to a 3-D strutted framework. The researchers in Japan, calling this the “chemical blowing method”, overcomes the weak intersheet connections that have made this type of structure so difficult to create in the past.
The field of metamaterials has produced structures with unprecedented abilities, including flat lenses, invisibility cloaks and even optical metatronic devices that can manipulate light in the way electronic circuitry manipulates the flow of electrons. Now, the birthplace of the digital computer, ENIAC, is using this technology in the rebirth of analog computing.
It's known that electric vehicles could travel longer distances before needing to charge and more renewable energy could be saved for a rainy day if lithium-sulfur batteries can just overcome a few technical hurdles. Now, a novel design for a critical part of the battery has been shown to significantly extend the technology's lifespan, bringing it closer to commercial use.
Researchers at Oak Ridge National Laboratory and the Univ. of Tennessee, Knoxville have pioneered a new technique for forming a 2-D, single-atom sheet of two different materials with a seamless boundary. The study could enable the use of new types of 2-D hybrid materials in technological applications and fundamental research.
Lithium batteries, with their exceptional ability to store power per a given weight, have been a major focus of research to enable use in everything from portable electronics to electric cars. Now researchers at Massachusetts Institute of Technology and Brookhaven National Laboratory have found a whole new avenue for such research: the use of disordered materials, which had generally been considered unsuitable for batteries.