Science & Technology News (813)
Posted: March 5, 2015 02:51PM
Even since the discovery of graphene, many have been searching for other two dimensional materials and what special properties they may possess. In the case of black phosphorus though, it has been known about for over one hundred years, but only recently has its potential been explored. Researchers at the University of Minnesota have discovered that it could be a new wonder material for optical communications and more.
The characteristic that perhaps most sets black phosphorus apart from graphene is its tunable band gap. While graphene lacks a band gap, making it a conductor, black phosphorus is actually a semiconductor, and the size of its band gap is dependent on its layer count. This opens up possibilities for use in computers and in optics, as the band gap influences how a material interacts with light. Because the band gap is tunable, so are the frequencies black phosphorus can absorb or emit. To test its real-world potential, the researchers built a photodetector using black phosphorus and succeeded at transmitting data at three billion (3,000,000,000) bits per second. As this is the first time such a photodetector has been built, you can expect that speed to increase.
The potential of black phosphorus extends beyond super-fast downloads because it is a direct-band semiconductor, which means it can efficiently emit light from electrical signals. This one material could potentially be used to both transmit and receive high speed optical signals between computers and within computer chips.
Source: University of Minnesota
Posted: March 5, 2015 06:50AM
I would rather not guess how many 2.4 GHz signals are passing through my body right now, with the various wireless devices just within arm's reach. While this frequency has served us quite well, to further increase bandwidth it may be necessary to go to high frequencies. Potentially frequencies in the terahertz range could be used, and researchers at the University of Utah have recently created a new filter that could help bring about the necessary technologies.
As the name suggests, terahertz frequencies are one thousand times greater than gigahertz frequencies, which means they could result in one thousand times more bandwidth. There are some issues to be addressed first, including creating filters for isolating specific frequencies. What the Utah researchers have found is that certain computer-generated designs can be used to print these filters with silver-metal ink from a conventional inkjet printer. Such filters would be necessary for creating the multiple wireless channels our various devices use.
There are still other issues to address though, including terahertz sources requiring line-of-sight and having a relatively short range. However many are still working to overcome these issues and wireless terahertz chips have been used to achieve impressive download speeds.
Source: University of Utah
Posted: March 4, 2015 02:27PM
Topological insulators are a curious family of materials, as they are capable of conducting electrical currents on their surface, but highly resistant through their bulk. By exploiting their properties, many new technologies could be developed involving spintronics and quantum computing. Now researchers at TU Dresden have discovered how to engrave wires into TIs.
Currents on a TI follow very small channels in the surface, and in the case of Bismuth-Rhodium-Iodine, these channels are connected to one dimensional steps at the edges of atomic layers. The physics of TIs keep electrons flowing along these channels from jumping to others, which is why there is so little resistance to these currents. What the Dresden researchers have done is engrave new channels into a TI, effectively etching wires into the surface. This discovery will help us understand the exact physics behind topological insulators, which is necessary for using them in future technologies.
Source: Technische Universität Dresden
Posted: March 4, 2015 06:23AM
Science fiction has long been providing us with devices capable of seeing otherwise invisible objects, and some of these technologies have come to exist. In the future we may see a new technology emerge called quantum radar that puts quantum mechanics to work catching things we cannot see. Researchers at the University of York have recently built a prototype quantum radar system that has potential for finding low reflectively objects, such as cancer cells and stealth aircraft.
Traditional radar works by sending out a microwave signal and capturing what bounces back. Objects with low reflectivity pose a problem though, as little comes back, and if there is a lot of noise in the area, finding something is going to be even harder. Quantum radar however couples a microwave beam to an optical beam, making it much more sensitive to small reflections, even in a noisy environment. What the York researchers specifically did was develop a special converter for entangling the two beams, for emission, and converting the microwave beam into an optical beam, for collection.
The researchers do acknowledge that quantum radars are still a ways off, but they could have a large number of applications. This includes non-invasive biomedical applications for analyzing proteins and acids, which expose patients to less radiation thanks to the low number of photons being used.
Source: University of York
Posted: March 3, 2015 02:23PM
Even though Einstein is best known for his theories of relativity, it was his paper on the photoelectric effect that earned him his Nobel Prize. A central concept to this paper was that light exists as both a particle and a wave, which was actually a matter of debate for centuries as different experiments can show it as one or the other. That limitation of experiments to show either the wave or the particle nature has continued until recently as researchers at EPFL have finally designed an experiment that shows both.
To finally catch light as both wave and particle, the researchers turned to electrons to capture the image. First a laser pulse was fired at a nanowire, causing its electrons to become excited and radiate light around the wire as a standing wave. Next the researchers fired a beam of electrons near the wire, because as they pass through the light, they will speed up or slow down. The image the researchers took showed the standing light wave, confirming the wave nature, but at the same time showed quantized energy packets. This indicates that the electrons were interacting with photons, the quanta or particle of light.
This is the first time the paradoxical nature of quantum mechanics has been directly demonstrated by an experiment, and will definitely impact fundamental science. It could also have applications with future technologies, like quantum computers, with its ability to image and control quantum phenomena.
Posted: March 3, 2015 05:57AM
We have all grown used to QR codes, most likely, as these codes are used in a variety of places to provide useful information or links to whoever pulls out their smartphone. They may be getting a new use in the future though, thanks to researchers at the University of Connecticut who want to use them to secure computer chips.
Believe it or not, but there are counterfeit computer chips being made out there, possibly with the purpose of making money but also to compromise security systems. Just a few years ago over 100 cases were revealed by a Senate Armed Services Committee report and fixing the issues of the counterfeit, Chinese electronics cost some $2.675 million. To try to prevent that from happening again, the Connecticut researchers suggest encoding vital statistics about computer chips into QA codes that are placed on the chips. By encrypting the data and compressing it all into the code, so an Internet connection is not required, the chips can be authenticated.
To further improve security, the researchers used a random phase photon-based encryption system to make the image hard to duplicate without knowing the appropriate codes. Instead of the white and black designs we may find around us, the resulting image can be microns in size and resemble a night sky with a few dots of pixelated light.
Source: University of Connecticut
Posted: March 2, 2015 06:53AM
Efficiency is important for just about all electronics, and that is not going to change any time soon. In fact if we do see the Internet of Things become a reality, efficiency is going to be key to connecting all of our various devices and appliances. To that end, researchers at MIT have developed a way to significantly improve the efficiency of radio chips by reducing off-state leakage.
Semiconductors are interesting electronic materials as they possess both conductive and insulating properties, which can be switched on and off. Because they are not perfect insulators, the transistors made of them can leak some energy when they are in their off-state. To improve the insulating properties, the researchers push a negative charge into a wire running across the transistor, as this stops the electrons that would otherwise leak out. A charge pump is used to create the negative charge.
As you may have guessed, this negative charge does take some power to produce, but at the cost of 20 picowatts, some 10,000 pW can be saved. If devices are going to start having sensors and transmitters built in to build an Internet of things, such efficiency will practically be a necessity.
Posted: February 27, 2015 09:58AM
The prospect of materials being able to carry electrical currents without resistance has been of great interest to people for a long time now, but achieving it has proven very difficult. Superconductivity is a somewhat fragile state, as many things can disrupt it, so we need to find ways to either remove these disruptions, or control them. Researchers at John Hopkins University have done the latter by trapping electron vortices.
Electron vortices occur in superconductors when they are exposed to magnetic fields, and they can disrupt the resistance-free supercurrents as they move around. Along the edge of the superconductor, the vortices will be pinned in place, but in the bulk of a material it is much harder to stop them from moving. The researchers' solution to the problem was to make an aluminum nanowire, as it is mostly edges. This caused the vortices to become trapped on the edge and form a single row, which the supercurrent was able to avoid.
Besides demonstrating a way to stop these vortices from interfering, this research could also prove useful in other ways. Some day we could see the vortices used to transmit information, like how electrical charges are used today.
Source: John Hopkins University
Posted: February 27, 2015 06:14AM
I am starting to wonder if graphene is more amazing or ridiculous as its number of applications continues to increase. Researchers at the University of Manchester have discovered that graphene oxide could be used to treat cancer. More specifically it can target cancer stem cells and prevent them from forming tumor-spheres.
Cancer stem cells (CSCs) are exactly what they sound like; cancer cells that can differentiate into other cancers and are what causes cancer to spread. They also have to do with cancer recurring after treatment. Graphene oxide has been investigated for use in biomedicine before, because it is able to enter or attach to cell surfaces, but this is the first time it has been shown to work as an anti-cancer drug on its own. It appears it attaches to the surfaces of the CSCs and blocks the pathways used to form tumor-spheres. The researchers also observed it triggering the differentiation of the CSCs into non-cancer stem cells. The tests were done with six different cancer types (breast, pancreatic, lung, brain, ovarian, and prostate) and it was effective against all of them, suggesting it could work with a larger number of cancers, and perhaps even all of them.
Normally CSCs are unaffected by radiation and chemotherapies, which kill bulk cancer cells, so a means to target them directly is very important. Of course a lot of work will have to be done before graphene oxide flakes could be used for treating cancer, but this is still a very significant discovery.
Source: University of Manchester
Posted: February 26, 2015 02:04PM
Many people want to see a future filled with superconductors, because these materials are capable of transmitting electricity without resistance. One of the reasons why we are not currently using them much is that they require being cooled to very low temperatures; some near absolute zero. Researchers at the University of Southern California however have recently discovered a potentially new class of superconductors based on superatoms.
Superatoms are homogenous clusters of normal atoms, so even though they consist of many atoms, they will act as one, though a rather large one. This made the researchers wonder if some phenomena, such as Cooper pairs, could by exhibited by the superatoms. Cooper pairs are pairs of electrons that form in superconductors and help achieve that superconductivity. To test this hypothesis the research built superatoms containing 37, 44, 66, and 68 atoms of aluminum and then shot lasers of increasing energy at them. Normally laser pulses of higher energy will cause more electrons to be ejected, but at certain energy levels the electrons resisted.
One explanation for this resistance is that the electrons had formed Cooper pairs, which is supported by fewer electrons being knocked at as the temperature dropped, with the critical point around 100 K. While that is still a pretty cold temperature, it is only the beginning so with more work, the researchers think they may be able to create superatoms with higher superconducting critical points.
Posted: February 26, 2015 06:38AM
For decades we have known about high temperature superconductors, but despite our time with them, we know little about how they work. With such understanding it may be possible to design new superconductors that work at room temperature. There is a model that may provide the explanation, and finally researchers at Rice University with an international team have taken an important step in testing the model.
The Hubbard model was developed in the 1960s to describe the magnetic and conduction properties of electrons in transition metals and their oxides. It is actually a simple model, but it becomes exponentially more difficult to process as more electrons are involved, which is why even supercomputers have been unable to test it. The solution the Rice researchers developed is to physically model the materials in question. Instead of working with electrons moving between sites in a lattice, the researchers placed ultracold atoms in an optical lattice and watched the movement of ions in the lattice. They observed antiferromagnetic order, just as the Hubbard model predicts, and by using the Quantum Monte Carlo method, the results of the experiment were confirmed to match the Hubbard model.
Even though it was not superconductivity that was observed, this is an important step towards that goal as most parent materials of high temperature superconductors are antiferromagnetic. By developing new measurement methods and finding ways to chill the atoms even more, the researchers hope to be able to model the electron pair correlations that result in superconductivity.
Source: Rice University
Posted: February 25, 2015 02:25PM
The world would be a very different place if not for batteries; especially modern lithium-ion batteries. These batteries seem to be approaching their limits though, unless new technologies and materials are developed. One thing holding back some new designs has been the formation of dendrites, but researchers at the Pacific Northwest National Laboratory have found a solution to that.
Dendrites are small structures that can form in batteries and lead to reduce capacities, short circuits, and even fires. If a material for a battery's anode reacts with the electrolyte to produce dendrites, it does not matter how much better that anode would be, because the battery will fail sooner. What the PNNL researchers have been investigating is new electrolytes that prevent dendrites from forming. In this area some others of have had success with electrolyte with high salt concentrations, so that is where the researchers started. They built a circular test cell with their new electrolyte and a lithium anode. Lithium anodes can hold ten times the energy of conventional graphite anodes, but easily form dendrites. In the test cell though, instead of dendrites forming, a thin layer of lithium nodules formed, which did not short-circuit the battery.
After 1000 cycles, the test cell still held 98.4% of its original energy at 4 milliAmps per square centimeter. With such high efficiency the researchers suspect it may be possible to do away with the anode in batteries using this electrolyte, and use a current collector, but more work needs to be done to determine that.
Posted: February 25, 2015 05:02AM
The traditional electronics we use every day are approaching their limits, so researchers have been working on a variety of replacements, including spintronics. Instead of relying on the charge of electrons, spintronics uses the spin of the fundamental particles, which can off several performance benefits. One of the challenges still to overcome though is finding a suitable material to make spintronics out of, but researchers at the University of Michigan have created one that could do the trick.
The ideal semiconductor for spintronics could have a number of its properties precisely tuned, including magnetism and conductivity. These characteristics can be tuned already by adding atoms to the crystal lattice, but typically this happens evenly across the whole semiconductor, and spintronics would want them to vary. To hopefully solve this problem, the researchers have developed a new material without a symmetrical crystal structure. That means the holes for accepting the doping atoms vary in size across the material, allowing for new arrangements and combinations.
The semiconductor is made of iron, bismuth, and selenium and while it has great potential, it will be a bit longer before it can be tested. So far the researchers have only made it in powder form, but next they plan on making it into the thin films that would actually be used in a spintronic device.
Source: University of Michigan
Posted: February 24, 2015 02:03PM
It is hard to say how many lenses you may have encountered in your life, but I know some I have come across have been quite large and thick. That may change in the future though, as many are looking to nanotechnology and metamaterials to create flat lenses. Now researchers at Harvard University have developed the first flat lens that can work with multiple frequencies of light at the same time.
Flat lenses have been built before, but they normally only focus one color of light, while others are diffracted at different angles. The Harvard researchers' new device however uses silicon antennas on a glass substrate to bend multiple colors of light at the same angle. Other designs would bend different frequencies at different angles, but this one compensates for that. So far the researchers have built two prototype achromatic metasurfaces, as they are calling the lenses, which are able to work with three different colors. One of the lenses deflects the three colors at the same angle, while the second instead focuses all three to the same point. Simulations suggest the design could be adapted to work with many more wavelengths than just three.
Flat lenses like these could be used in a variety of optical devices, including microscopes, telescopes, and even computers. Anywhere that the bulk of traditional lenses can pose a problem, this research could be applied.
Source: Harvard University
Posted: February 24, 2015 06:44AM
There are many applications for 3D printing, and not least among them are medical uses such as specialized scaffolds that direct and promote cell growth. Researchers at the University of Sheffield have recently printed a nerve guidance conduit (NGC) which is able to guide nerve ends to repair naturally. This could have an enormous impact on future treatments for various traumatic injuries.
Normally repairing nerve damage involves surgery that sutures or grafts endings together, which tends to produce imperfect results. The use of an NGC however can improve results, as its framework of tubes guide nerve ends to toward each other for natural repairs. Some are already used in surgery, but they are limited in design and materials, which naturally restricts the injuries they can be used to treat. By using Computer Aided Design (CAD) and a form of 3D printing (laser direct writing) the Sheffield researchers are able to craft NGCs for any kind of nerve damage, and even tailor designs for specific patients.
The researchers have tested their NGCs using a novel mouse model and shown that they were able demonstrate a repair over an injury gap of 3 mm in just three weeks. With more work the printed NGCs could be made to repair larger injuries, and be made from biodegradable materials.
Source: University of Sheffield
Posted: February 23, 2015 02:08PM
In one way or another, chances are that we all rely on wireless communications like cellular connections or Wi-Fi. These various technologies have been serving us well for years now, but like all technologies, we want them to improve and that is going to require pushing limits and entering new territories. In this case, those new territories are higher frequencies and to help us get there, NIST is developing tools to measure signals at these higher frequencies.
Most wireless communications today operate below 3 GHz, but thanks to silicon-germanium radio chips we are reaching into the millimeter wavelengths, which are above 10 GHz. The NIST researchers are aiming for 100 GHz, and greater. One of the issues with frequencies this high is that the high speed circuits needed to generate them can also distort them. Even small errors can pose a problem. Also mm waves have a harder time going around corners than lower frequencies, which will make modeling the wireless channels more difficult. One way to solve that problem is to use complex arrays of antennas that allow beams to be steered directly to devices.
So far the researchers have built test receivers and channel sounders and demonstrated a calibrated signal source capable of generating 44 GHz and 94 GHz signals. The source uses commercial parts, so companies should be able to build their own systems for testing.
Posted: February 23, 2015 05:52AM
Always in science, a failure is something to learn from, and sometimes a failure is just an unexpected success. Such was the case for some MIT researchers who accidentally discovered a way to produce a pure silicon core in a fiber. This discovery could potentially lead to many new technologies, if more complex electronics structures can be built inside the fibers.
Originally the researchers were trying to find ways to incorporate metal wires inside of fibers, so they were working with common silica and silver, copper, and aluminum. They would start by arranging the materials inside what is called a preform, which is a larger block or cylinder, and then heat and draw it out, resulting in a thin fiber with the same composition as the preform. At least that is what they expected, but when the fiber with aluminum was pulled out, instead of a shiny metallic core, the core was a darker material. Initially the sample was going to be discarded as a failure, but the researchers instead decided to examine it more closely and found that the black core was actually pure silicon. What happened was actually a well-known chemical reaction, which converted the silica and aluminum into pure silicon and aluminum oxide.
With a pure silicon core, these fibers could be used to build advanced electronics, like transistors or solar cells, if other materials could be integrated as well. The best part though might be that the process starts with inexpensive silica and gives you pure silicon in the end, instead of requiring the more expensive material at the beginning.
Posted: February 20, 2015 02:49PM
If you are not convinced that quantum mechanics is weird, keep reading and check out the source too. For the physics we live with every day, time runs in one direction, and the past influences the future, but not the other way around. As researchers at Washington University in St. Louis have discovered though, in the quantum world the future and the past can influence the state of a system, instead of just the past.
In our normal world, if you follow a system up to some event, you can predict what happens with the information you collected. In quantum mechanics though, the odds of guessing right are about 50-50, even if you know everything about a quantum particle leading up to the event. To confirm this, the researchers put a superconducting circuit into a superposition, creating a qubit, and placed it in a microwave box. When some microwave photons are put in the box, they will interact with the qubit and gain some information about it, without collapsing the superposition. The researchers then took a strong measurement of the qubit, which would cause it to collapse, but they hid the result and continued using the photons to make weak measurements.
When the researchers predicted what the strong measurement would be using just the information leading up to it, they were correct half of the time. However, when they ran the equations backwards with the weak measurements following the hard measurement, creating hindsight predictions or "retrodictions," they were right 90% of the time. This indicates that the state of the qubit incorporates information not only from what led up to the strong measurement, but also from what followed it. This results returns time symmetry to quantum mechanics and could have some interesting applications, such as making more robust chemical reactions and improving quantum computing.
Posted: February 20, 2015 06:25AM
When you look up into the night sky, you can think about how remote much of the Universe is, but some of it was once closer than you may think. Researchers at the University of Rochester and institutions across the world, have recently determined that a star likely passed within a light year of the Sun about 70,000 year ago.
Called Scholz's star for its discoverer, the star is a dim red dwarf, about 8% the Sun's mass, and is part of a binary system that includes a brown dwarf, that weighs in at 6% of the Sun's mass. Currently it is about 20 light years away but it has some unusual characteristics. The main thing is that it has little tangential motion, which means it is moving almost directly away from the Solar System, unlike most stars at that distance. This indicates it either passed by us in the past, or will in the future. Radial velocity measurements showed that it is moving away, so it must have gone by us before. To determine when it did and what its influence may have been, the researchers modelled its orbit 10,000 times, and of those 98% showed it passed through the outer Oort cloud, at a distance of just 0.8 light years away.
While it may have passed through the outer Oort cloud, which is at the edge of the Solar System and holds trillions comets, it likely did not perturb it much. It may have been visible to humans 70,000 years ago, because even though it is too dim to see with the naked eye, it could have flared and become visible for minutes or hours at a time.
Source: University of Rochester
Posted: February 19, 2015 02:08PM
When we have work to do, we like keeping what we need nearby, to speed up the process. The processing cores in our computers also like keeping their work nearby, but finding the best placement is anything but easy. However, researchers at MIT have developed a new optimization algorithm that is significantly faster than others, and could significantly speed up processors.
The problem has to do with the placement of data and keeping the related computations nearby. This is similar to the 'place and route' problem of minimizing the distance between logic circuits, which is NP-hard, meaning it is computationally impossible to find the optimal solution to. However, algorithms that approximate the optimal solution can be run over the course of several hours. The new MIT algorithm however completes in just 25 milliseconds and is better than 99% efficient, compared to those other algorithms. It works by roughly placing the data across the memory banks, to keep it all spread out and not clumped into the same area. It then places the computational threads near the data, and refines the placement of the data, based on the placement of the threads. While this process could be repeated, it only provides a 1% increase, which is not exactly worth it. When the researchers applied the algorithm to a simulated 64-core chip, it improved computational speeds by 64% and reduced power consumption by 36%.
If built into real chips, the dedicated circuitry would take up about 1% of the chip's area. The researchers believe chipmakers will consider this a fair loss, considering the performance improvements this algorithm could provide by constantly monitoring a processor.
Posted: February 19, 2015 06:45AM
Battery technology is quickly approaching a limit that can only be avoided with new materials, as graphite electrodes can only hold so many ions. Other materials are being investigated, but they present their own challenges, like silicon's significant expansion as it absorbs ions. Researchers at the University of California, Riverside have found a way around that problem though, and another, with nanofibers.
In theory, lithium-ion batteries that use silicon electrodes could store ten times more energy, because silicon can hold that many much more charge for its weight. The problem is that as the silicon absorbs ions, it expands so much that it can fracture and degrade performance or destroy the battery. The Riverside researchers however are working with silicon nanofibers in a sponge-like structure that can get around that expansion issue. They make the fibers using electrospinning, which applies 20,000 to 40,000 volts to a rotating drum and nozzle as it emits a solution of tetraethyl orthosilicate. This materials used in the semiconductor industry, and by exposing it to a magnesium vapor, the sponge-like structure is produced.
While the ability of the silicon to survive hundreds of charge/discharge cycles is significant on its own, the production method offers another benefit. In the lab the researchers were able to create several grams of the material, while other potential graphite replacements, like carbon nanotubes and silicon nanowires, are only produced micrograms at a time.
Posted: February 18, 2015 02:14PM
Currently, Earth supports the only known life in the Universe, but it took a long time before the planet could support much life. One of the steps required for this transformation was for nitrogen to be pulled out of the atmosphere so it could build various molecules necessary for life. Analysis of these nitrogen-fixing enzymes puts their age between 1.5 and 2.2 billion years, but researchers at the University of Washington have found evidence to push that back another billion years.
For their study, the researchers used fifty-two rock samples between 2.75 and 3.2 billion years old, and they represent some of the oldest and best-preserved rocks on the planet. Part of the reason these rocks are so well preserved is because they formed before the atmosphere gained oxygen, which can destroy chemical clues. All of these rocks, even the oldest ones, indicated nitrogen was being pulled out of the air by the ratio of heavier and lighter nitrogen isotopes. This ratio could only be achieved in the presence of nitrogen-fixing enzymes in single-celled organisms.
Further analysis of the rock samples indicate the enzyme was based on molybdenum, which is common today, but indicates something else about that prehistoric life. Today molybdenum-based enzymes are common because of oxygen reacting with rocks and it washing into the ocean, but little oxygen would have been present 3.2 billion years ago. To explain this, the researchers suggest that some life may have existed on land, releasing enough oxygen to provide the necessary molybdenum.
Source: University of Washington
Posted: February 18, 2015 06:33AM
Most materials will expand, if only slightly, when heated but there are some polymers that will actually expand when cooled. These shape-memory polymers have some drawbacks though, but researchers at the University of Rochester have developed a new material without those issues.
Normally shape-memory polymers need to be programmed each time they are heated and cooled, as to what shape they are supposed to take on. This programming requires attaching small loads to it to direct the process. The Rochester researchers got around this by introducing permanent stress inside of the material. When the material was heated, they attached a load to cause it to take a shape. They then added crosslinks to the otherwise loose network of molecules, so when the material cooled and crystallized, it did so in a preferred direction. By building the stress into the molecular structure, the loads are no longer necessary for the material to remember what shape to take when cooled. Even after multiple heating and cooling cycles, the material returned to its original and programmed shape without noticeable deviation.
Besides being cool, a shape-memory polymer like this could find many useful applications with biotechnology, artificial muscles, and robotics. Next the researchers are working on optimizing the system by adjusting how the crosslinks tie together.
Source: University of Rochester
Posted: February 17, 2015 02:46PM
Two dimensional materials have been of great interest for years now, as they can possess some very unusual and useful properties. Graphene is a prime example of this, with it tremendous strength, conductivity, and flexibility, and so is germanane, an atom-thick sheet of germanium. Germanane was first made a couple years ago at Ohio State University, and since then the researchers have been tinkering with it and making some interesting discoveries.
There is a little irony to the work with germanane for potential use in future computers, as germanium was used to make transistors before silicon, the current standard. The researchers are trying to keep the work within what is possible with silicon fabrication methods though. Part of their work has been focused on manipulating germanane's optical properties. It already transmits electron some 10 times faster than silicon and is better at absorbing light, but by tuning germanane's electron structure, it may be able to interact with a significantly wider portion of the spectrum than currently possible. This could lead to improved LEDs, lasers, solar cells, and more.
The researchers have also been investigating a 2D tin material by making germanane samples that contain 9% tin atoms. It has been theoretically predicted that a 2D tin material would be a topological insulator and capable of transmitting electrons with 100% efficiency, at room temperature. The predictions also state that only certain bonds would form on the material's top and bottom, which the researchers observed with the germanane samples.
Source: Ohio State University
Posted: February 17, 2015 07:09AM
Vision is a very important sense and many people would say they cannot live without it, so naturally many technologies have been developed to correct imperfect vision. Age-related macular degeneration is the leading cause of blindness in older adults, so it has gotten some special attention. Researchers from Ecole Polytechnique Fédérale de Lausanne recently demonstrated telescopic contact lenses and smart glasses for fighting the condition.
The contact lenses utilize a thin reflective telescope made of plastics, aluminum mirrors, polarizing thin films, and biologically safe glues to hold it all together. When light enters the lenses, it is bounced around by the mirrors, to expand the image resulting in a 2.8 times magnification. To keep the lenses safe to use, the researchers have incorporated 0.1 mm wide air channels in them, to allow oxygen to reach the eye.
The glasses work with the contact lenses to select whether you see a normal or magnified image. When you wish to see normal vision, the glasses allow through light of with the polarization matching the lenses' 1x aperture, while a different polarization matches the 2.8x aperture. The glasses have a light source and detector in order to distinguish winks from blinks, because it is winking one eye or the other that switches between the magnifications.
Posted: February 16, 2015 07:03AM
Every day, information about our past is lost as people die, films fade, and objects erode away. While there are many preservations initiatives to prevent the loss of our history, a means to store this information for the long term is still needed. One possibility is to write the information into DNA, and now researchers at ETH Zurich have found a way to overcome that particular medium's issues.
One of the issues of DNA data storage is that the DNA must be protected from the environment. Samples that are hundreds of thousands of years old are retrieved from bones, so to replicate this protection, the researchers used silica microspheres some 150 nm wide. The researchers tested it against the DNA being stored in a biopolymer and on impregnated filter paper, and it showed itself to be particularly robust. It is also rather easy to retrieve the DNA using a fluoride solution.
Another issue is that errors can occur in the data, which is naturally undesirable for long-term data storage. To address this, the researchers applied a scheme similar to those used for long-range data transmission and found it enabled the data to be retrieved, error-free.
Source: ETH Zurich
Posted: February 13, 2015 02:45PM
Metamaterials are a curious class of materials that have the unique quality of possessing properties not found in Nature. Some of these materials' properties have been engineered by the people making them, but not all of them. The nonlinear optical properties are one example where the physics still need to be understood, but now researchers at Berkeley Lab have found a theory to predict these properties.
If you shine a light into a material, you expect the color of the light to remain the same, but some materials will change it. These are called nonlinear materials and they have a number of uses, for example some lasers use them to produce otherwise unobtainable higher frequencies of light. Some metamaterials are also nonlinear, but they cannot be described with the same rule used for natural materials. What the Berkeley researchers have found is that a nonlinear light scattering theory developed for nanostructures actually does work.
Metamaterials with their engineered optical properties could see use in advanced microscopes and other devices, but all of their properties will have to be understood first. By discovering this theory can be applied, that level of understanding is coming closer.
Source: Berkeley Lab
Posted: February 13, 2015 06:51AM
Fairly often we want to present ourselves in the best light by focusing on our successes and avoiding or downplaying our failings, because we think it will make us look better in the eyes of others. Researchers at the University of Iowa decided to investigate how effective that strategy is for online dating profiles and found that looking perfect is not the perfect plan.
The researchers put together eight profile, four men and four women, that lay along the spectrum between Selective Self-Presentation (SSP) and Warranting. Warranting contains information that is easily traced to a real person, such as links to what is mentioned in the profile, while SSP only shows what is good about the person. These profiles were then shown to 317 adults, of which 150 were men and 167 were women, with an average age of 40. The researchers expected the high SSP profiles, which sounded perfect, to be the most popular, but the reverse was the case.
Instead of the perfect profiles, the people preferred the more realistic profiles as they viewed it as more trustworthy. It appears this may come from the expectation of people misrepresenting themselves in these profiles, making the realistic ones more appreciated.
Source: University of Iowa
Posted: February 12, 2015 02:05PM
It is never fun to catch the flu, so it is not surprising that a number of treatments have been developed, from those deployed by doctors to old wives' tales. To help improve and discover new strategies, researchers at the University of Oxford have built the first complete model of the outer envelope of an influenza A virion.
A virion is a complete virus particle, so modeling it allows people researchers to study how it behaves in different environments, and the efficacy of drugs meant to destroy the virus. In this case the researchers made the interesting discovery that the spike proteins on the particle's membrane spread out, instead of moving closer together. These proteins impact how the virion interacts with its host cell, and this information could be used to better design antigens.
Currently the model only spans a very short period of time for a single virion, but overtime it may expand to multiple particles in various environments. This would be useful for learning how the particles behave and survive over the course of a year.
Posted: February 12, 2015 07:01AM
Chances are that if you have been following displays in recent years you have heard about OLEDs. There is great interest in them because pixels in an OLED display emit their own light, instead of needing a backlight, and the displays can be flexible. While there are many products that use them, OLED displays are still uncommon in part because they are still expensive, but that should be changing soon, thanks to researchers at MIT and their startup Kateeva.
Like many relatively young technologies, the promise of OLEDs has been talked about a lot, but not all of them have been realized. The flexibility of the thin films has been demonstrated, as has the improved brightness and saturation, thanks to the pixels directly emitting light. What has not quite materialized yet though is the lower cost of manufacturing. This is what the MIT researchers have tackled with their inkjet-like YIELDjet platform. YIELDjet FLEX is one of two technologies they have developed, and this one protects the OLED material from being exposed to contaminates by using a nitrogen chamber. Normally a vacuum chamber would be used, but the nitrogen chamber is ten times more effective and cuts down on waste and cost. The researchers hope to see displays made with YIELDjet FLEX in products by the end of the year.
The second YIELDjet technology the researchers have created removes the need of shadow masks for laying down patterns. Instead of the masks, which cause waste and can cause defects, the new system uses print heads with hundreds of nozzles to deposit the OLED materials directly onto a substrate. This could potentially cut the costs of larger displays by half.