Commonly known as NC State or simply State, the university is part of the University of North Carolina system and is a land, sea, and space grant institution. The university forms one of the corners of the Research Triangle together with Duke University in Durham and The University of North Carolina at Chapel Hill.
The North Carolina General Assembly founded the North Carolina College of Agriculture and Mechanic Arts, now NC State, on March 7, 1887, as a land-grant college. Today, NC State has an enrollment of more than 34,000 students, making it the largest university in the Carolinas.
NC State has historical strengths in engineering, agriculture, life sciences, textiles and design and now offers 106 bachelor’s degrees. The graduate school offers 104 master’s degrees, 61 doctoral degrees, and a Doctor of Veterinary Medicine.
North Carolina State University research articles from Innovation Toronto
- Metal Foam Obliterates Bullets – and That’s Just the Beginning – April 11, 2016
- Study Finds Metal Foam Handles Heat Better Than Steel – March 29, 2016
- Modified Maggots Could Help Human Wound Healing – March 25, 2016
- Scientists create painless patch of insulin-producing beta cells to control diabetes – March 15, 2016
- Magnetic Nanoparticle Chains Offer New Technique for Controlling Soft Robots – December 19, 2015
- Researchers find new phase of carbon – Q-carbon, make diamond at room temperature – December 6, 2015
- Liquid Metal Nano-Terminators Target Cancer Cells – December 3, 2015
- Researchers Find Way to Create Wide Variety of New Holograms – November 11, 2015
- Metal Foams Capable of Shielding X-rays, Gamma Rays, Neutron Radiation – July 19, 2015
- Smart insulin patch could replace painful injections for diabetes – June 25, 2015
- The Next Big Step in 3-D printing technology – liquids – March 18, 2015
- New ‘High-Entropy’ Alloy Is As Light As Aluminum, As Strong as Titanium Alloy – December 13, 2014
- Cockroach Cyborgs Use Microphones to Detect, Trace Sounds – November 7, 2014
- Research Paves Way for Cyborg Moth ‘Biobots’ – August 23, 2014
- Inspired by Nature, Researchers Create Tougher Metal Materials – July 5, 2014
- ‘Sensing Skin’ Quickly Detects Cracks, Damage in Concrete Structures – June 25, 2014
- ‘Nanodaisies’ Deliver Drug Cocktail to Cancer Cells – May 30, 2014
- Bee Biodiversity Boosts Blueberry Crop Yields – May 12, 2014
- New Ultrasound Device May Aid in Detecting Risk for Heart Attack, Stroke – April 28, 2014
- Atomic-Scale Catalysts May Produce Cheap Hydrogen
- Silver Nanowire Sensors Hold Promise for Prosthetics, Robotics
- New Technique Targets Specific Areas of Cancer Cells with Different Drugs | cancer-killing drugs
- Simple Technique May Drive Down Biofuel Production Costs
- Researchers Find Simple, Cheap Way to Increase Solar Cell Efficiency
- Researchers Find Ways to Minimize Power Grid Disruptions from Wind Power
- Ultrasound, Nanoparticles May Help Diabetics Avoid the Needle for Days at a Time
- New Approach Advances Wireless Power Transfer for Vehicles
- Study Finds Natural Compound Can Be Used for 3-D Printing of Medical Implants
- Software Uses Cyborg Swarm To Map Unknown Environs
- Scientists develop heat-resistant materials that could vastly improve solar cell efficiency
- Researchers Seek to Control Prosthetic Legs with Neural Signals
- Scaling Up Personalized Query Results for Next Generation of Search Engines
- New magnetic semiconductor material holds promise for ‘spintronics’
- Airbrushing Could Facilitate Large-Scale Manufacture of Carbon Nanofibers
- New Connection between Stacked Solar Cells Can Handle Energy of 70,000 Suns
- Self-Healing Solar Cells ‘Channel’ Natural Processes
- Researchers Create ‘Soft Robotic’ Devices Using Water-Based Gels
- Injectable ‘Smart Sponge’ Holds Promise for Controlled Drug Delivery
- Crop watering by phone
- Researchers perform DNA computation in living cells
- Mapping Out How to Save Species
- Researchers Build 3-D Structures Out of Liquid Metal at Room Temperature
- New Metallic Bubble Wrap Offers Big Benefits Over Other Protective Materials
- Teaching a Computer to Play ‘Concentration’ Advances Security, Understanding of the Human Mind
- Light-Carved ‘Nano-Volcanoes’ Hold Promise for Drug Delivery
- New Technique May Open Up an Era of Atomic-scale Semiconductor Devices
- New Software Spots, Isolates Cyber-Attacks to Protect Networked Control Systems
- New Mechanism Converts Natural Gas to Energy Faster, Captures CO2
- Injectable Nano-Network Controls Blood Sugar in Diabetics for Days at a Time
- Researchers Devise X-ray Approach to Track Surgical Devices and Minimize Radiation Exposure
- Researcher Finds Faster, More Efficient Technique for Creating High-Density Ceramics
- Researchers Create Flexible, Nanoscale ‘Bed of Nails’ for Possible Drug Delivery
- Researchers Use Liquid Metal to Create Wires That Stretch Eight Times Their Original Length
- Researchers Find Way to Boost WiFi Performance 400-700 Percent
- Additive Restores Antibiotic Effectiveness Against MRSA
- Researchers Create ‘Nanoflowers’ for Energy Storage, Solar Cells
- Researchers Develop Technique to Remotely Control Cockroaches
- Researchers Almost Double Light Efficiency in LC Projectors
- Researchers Send ‘Wireless’ Message Using a Beam of Neutrinos
- Elastic conductors made from carbon nanotubes
- Cracking Open the Scientific Process
- New technique turns 2D patterns into 3D objects using nothing but light
- Professor to display frying invention on Food Network
- Soft, submersible memory device created
- Conductive nanocoatings for textiles could lead to thin, flexible electronics
- Software tool allows programs to run faster without sacrificing security
- Voiding Defects: New Technique Makes LED Lighting More Efficient
- New Device May Revolutionize Computer Memory
- Coiled nanowire key to stretchable electronics
- ‘Superstreet’ concept shows promise in real-world test
- Shoe-based radar system points the way when the GPS is not working
- Researchers create nano-architectured aluminum alloy with strength of steel
- New method to predict how nanoparticles will react in the human body
- New Research May Revolutionize Ceramics Manufacturing
- Research points to full-screen braille reading possibilities
- Smart Coating Opens Door to Safer Hip, Knee and Dental Implants
- `Smart grid’ power lines move into digital age
- Non-toxic Hull Coating Resists Barnacles, May Save Ship Owners Millions
Researchers from North Carolina State University, the University of North Carolina at Chapel Hill and First Affiliated Hospital of Zhengzhou University have developed a synthetic version of a cardiac stem cell. These synthetic stem cells offer therapeutic benefits comparable to those from natural stem cells and could reduce some of the risks associated with stem cell therapies. Additionally, these cells have better preservation stability and the technology is generalizable to other types of stem cells.
Stem cell therapies work by promoting endogenous repair; that is, they aid damaged tissue in repairing itself by secreting “paracrine factors,” including proteins and genetic materials. While stem cell therapies can be effective, they are also associated with some risks of both tumor growth and immune rejection. Also, the cells themselves are very fragile, requiring careful storage and a multi-step process of typing and characterization before they can be used.
Ke Cheng, associate professor of molecular biomedical sciences at NC State, associate professor in the joint biomedical engineering program at NC State and UNC, and adjunct associate professor at the UNC Eshelman School of Pharmacy, led a team in developing the synthetic version of a cardiac stem cell that could be used in off-the-shelf applications.
Cheng and his colleagues fabricated a cell-mimicking microparticle (CMMP) from poly (lactic-co-glycolic acid) or PLGA, a biodegradable and biocompatible polymer. The researchers then harvested growth factor proteins from cultured human cardiac stem cells and added them to the PLGA. Finally, they coated the particle with cardiac stem cell membrane.
“We took the cargo and the shell of the stem cell and packaged it into a biodegradable particle,” Cheng says.
When tested in vitro, both the CMMP and cardiac stem cell promoted the growth of cardiac muscle cells. They also tested the CMMP in a mouse model with myocardial infarction, and found that its ability to bind to cardiac tissue and promote growth after a heart attack was comparable to that of cardiac stem cells. Due to its structure, CMMP cannot replicate – reducing the risk of tumor formation.
“The synthetic cells operate much the same way a deactivated vaccine works,” Cheng says. “Their membranes allow them to bypass the immune response, bind to cardiac tissue, release the growth factors and generate repair, but they cannot amplify by themselves. So you get the benefits of stem cell therapy without risks.”
The synthetic stem cells are much more durable than human stem cells, and can tolerate harsh freezing and thawing. They also don’t have to be derived from the patient’s own cells. And the manufacturing process can be used with any type of stem cell.
“We are hoping that this may be a first step toward a truly off-the-shelf stem cell product that would enable people to receive beneficial stem cell therapies when they’re needed, without costly delays,” Cheng says.
An interdisciplinary team of researchers has developed a smart patch designed to monitor a patient’s blood and release blood-thinning drugs as needed to prevent the occurrence of dangerous blood clots – a condition known as thrombosis.
In an animal model, the patch was shown to be more effective at preventing thrombosis than traditional methods of drug delivery. The work was done by researchers at North Carolina State University and the University of North Carolina at Chapel Hill.
Thrombosis occurs when blood clots disrupt the normal flow of blood in the body, which can cause severe health problems such as pulmonary embolism, heart attack or stroke. Current treatments often rely on the use of blood thinners, such as Heparin, which require patients to test their blood on a regular basis in order to ensure proper dosages. Too large a dose can cause problems such as spontaneous hemorrhaging, while doses that are too small may not be able to prevent a relapse of thrombosis.
“Our goal was to generate a patch that can monitor a patient’s blood and release additional drugs when necessary; effectively, a self-regulating system,” says Zhen Gu, co-corresponding author on a paper describing the work. Gu is an associate professor in the joint biomedical engineering program at NC State and UNC.
“Two years ago, I spoke with Zhen Gu about the significant clinical need for precise delivery of blood thinners,” says Caterina Gallippi, a co-corresponding author and associate professor in the joint biomedical engineering program. “We, together with Professor Yong Zhu in the mechanical engineering department at NC State, assembled a research team and invented this patch.”
The patch incorporates microneedles made of a polymer that consists of hyaluronic acid (HA) and the drug Heparin. The polymer has been modified to be responsive to thrombin, an enzyme that initiates clotting in the blood.
When elevated levels of thrombin enzymes in the bloodstream come into contact with the microneedle, the enzymes break the specific amino acid chains that bind the Heparin to the HA, releasing the Heparin into the blood stream.
“The more thrombin there is in the bloodstream, the more Heparin is needed to reduce clotting,” says Yuqi Zhang, a Ph.D. student in Gu’s lab and co-lead author of the paper. “So we created a disposable patch in which the more thrombin there is in the blood stream, the more Heparin is released.”
“We will further enhance the loading amount of drug in the patch. The amount of Heparin in a patch can be tailored to a patient’s specific needs and replaced daily, or less often, as needed,” says Jicheng Yu, a Ph.D. student in Gu’s lab and the other co-lead author of the paper. “But the amount of Heparin being released into the patient at any given moment will be determined by the thrombin levels in the patient’s blood.”
The research team tested the HA-Heparin smart patch in a mouse model. In the experiments, subjects were injected with large doses of thrombin, which would result in fatal blood clotting of the lungs if left untreated.
In the first experiment, mice were either left untreated, given a shot of Heparin, or given the HA-Heparin smart patch. The mice were injected with thrombin 10 minutes later. Fifteen minutes after the thrombin injection, only the mice who received no treatment died.
In the second experiment, the thrombin was injected six hours after treatment. Fifteen minutes after the thrombin injection, all of the mice with the HA-Heparin smart patch were fine, but around 80 percent of the mice that received the Heparin shot had died.
“We’re excited about the possibility of using a closed-loop, self-regulating smart patch to help treat a condition that affects thousands of people every year, while hopefully also driving down treatment costs,” Gu says. “This paper represents a good first step, and we’re now looking for funding to perform additional preclinical testing.”
Researchers at North Carolina State University have developed a combination of software and hardware that will allow them to use unmanned aerial vehicles (UAVs) and insect cyborgs, or biobots, to map large, unfamiliar areas – such as collapsed buildings after a disaster.
“The idea would be to release a swarm of sensor-equipped biobots – such as remotely controlled cockroaches – into a collapsed building or other dangerous, unmapped area,” says Edgar Lobaton, an assistant professor of electrical and computer engineering at NC State and co-author of two papers describing the work.
“Using remote-control technology, we would restrict the movement of the biobots to a defined area,” Lobaton says. “That area would be defined by proximity to a beacon on a UAV. For example, the biobots may be prevented from going more than 20 meters from the UAV.”
The biobots would be allowed to move freely within a defined area and would signal researchers via radio waves whenever they got close to each other. Custom software would then use an algorithm to translate the biobot sensor data into a rough map of the unknown environment.
Once the program receives enough data to map the defined area, the UAV moves forward to hover over an adjacent, unexplored section. The biobots move with it, and the mapping process is repeated. The software program then stitches the new map to the previous one. This can be repeated until the entire region or structure has been mapped; that map could then be used by first responders or other authorities.
“This has utility for areas – like collapsed buildings – where GPS can’t be used,” Lobaton says. “A strong radio signal from the UAV could penetrate to a certain extent into a collapsed building, keeping the biobot swarm contained. And as long as we can get a signal from any part of the swarm, we are able to retrieve data on what the rest of the swarm is doing. Based on our experimental data, we know you’re going to lose track of a few individuals, but that shouldn’t prevent you from collecting enough data for mapping.”
Co-lead author Alper Bozkurt, an associate professor of electrical and computer engineering at NC State, has previously developed functional cockroach biobots. However, to test their new mapping technology, the research team relied on inch-and-a-half-long robots that simulate cockroach behavior.
In their experiment, researchers released these robots into a maze-like space, with the effect of the UAV beacon emulated using an overhead camera and a physical boundary attached to a moving cart. The cart was moved as the robots mapped the area. (Video from the experiment is available at https://www.youtube.com/watch?v=OWnrGsJEw6s&feature=youtu.be.)
“We had previously developed proof-of-concept software that allowed us to map small areas with biobots, but this work allows us to map much larger areas and to stitch those maps together into a comprehensive overview,” Lobaton says. “It would be of much more practical use for helping to locate survivors after a disaster, finding a safe way to reach survivors, or for helping responders determine how structurally safe a building may be.
“The next step is to replicate these experiments using biobots, which we’re excited about.”
For the first time, a team including scientists from the National Institute of Standards and Technology (NIST) have used neutron beams to create holograms of large solid objects, revealing details about their interiors in ways that ordinary laser light-based visual holograms cannot.
Holograms—flat images that change depending on the viewer’s perspective, giving the sense that they are three-dimensional objects—owe their striking capability to what’s called an interference pattern. All matter, such as neutrons and photons of light, has the ability to act like rippling waves with peaks and valleys. Like a water wave hitting a gap between the two rocks, a wave can split up and then re-combine to create information-rich interference patterns(link is external).
An optical hologram is made by shining a laser at an object. Instead of merely photographing the light reflected from the object, a hologram is formed by recording how the reflected laser light waves interfere with each other. The resulting patterns, based on the waves’ phase differences(link is external), or relative positions of their peaks and valleys, contain far more information about an object’s appearance than a simple photo does, though they don’t generally tell us much about its hidden interior.
Hidden interiors, however, are just what neutron scientists explore. Neutrons are great at penetrating metals and many other solid things, making neutron beams useful for scientists who create a new substance and want to investigate its properties. But neutrons have limitations, too. They aren’t very good for creating visual images; neutron experiment data is usually expressed as graphs that would look at home in a high school algebra textbook. And this data typically tells them about how a substance is made on average—fine if they want to know broadly about an object built from a bunch of repeating structures like a crystal(link is external), but not so good if they want to know the details about one specific bit of it.
But what if we could have the best of both worlds? The research team has found a way.
The team’s previous work, performed at the NIST Center for Neutron Research (NCNR), involved passing neutrons through a cylinder of aluminum that had a tiny “spiral staircase” carved into one of its circular faces. The cylinder’s shape imparted a twist to the neutron beam, but the team also noticed that the beam’s individual neutrons changed phase depending on what section of the cylinder they passed through: the thicker the section, the greater the phase shift. Eventually they realized this was essentially the information they needed to create holograms of objects’ innards, and they detail their method in their new paper.
The discovery won’t change anything about interstellar chess games, but it adds to the palette of techniques scientists have to explore solid materials. The team has shown that all it takes is a beam of neutrons and an interferometer—a detector that measures interference patterns—to create direct visual representations of an object and reveal details about specific points within it.
“Other techniques measure small features as well, only they are limited to measuring surface properties,” said team member Michael Huber of NIST’s Physical Measurement Laboratory. “This might be a more prudent technique for measuring small, 10-micron size structures and buried interfaces inside the bulk of the material.”
The research was a multi-institutional collaboration that included scientists from NIST and the Joint Quantum Institute(link is external), a research partnership of NIST and the University of Maryland, as well as North Carolina State University and Canada’s University of Waterloo.
Paper: D. Sarenac, M.G. Huber, B. Heacock, M. Arif, C.W. Clark, D.G. Cory, C.B. Shahi and D.A. Pushin. Holography with a neutron interferometer. Optics Express. DOI: 10.1364/OE.24.022528(link is external).
Neutron Holography Video
Though they aren’t holograms themselves, these animations demonstrate data that proved that neutron beams—rather than the usual laser light—can be used to create holograms of solid objects, in this case a tiny aluminum plate with a spiral carved into one of its faces.
The first animation illustrates what happens as you slowly move back from the plate, which dominates as the bright circle in the center. Near the end, fainter circles appear at top and bottom (created by interference patterns in the neutron beams) that usefully show the outlines of the plate’s spiral surface.
Animation of neutron scanning data, demonstrating that scientists can use neutron beams to create holograms instead of the usual laser light.
Passing the neutron beam through successively thicker portions of the spiral plate produces the interference data used to create the second animation below, whose “fork” grows greater numbers of tines at right as the plate’s thickness increases. Combining these data with other neutron measurements can produce 3-D holograms, which could make neutron scan results easier for scientists to interpret visually.
Animation of neutron scanning data, demonstrating that scientists can use neutron beams to create holograms instead of the usual laser light.
Researchers at North Carolina State University have created a high voltage and high frequency silicon carbide (SiC) power switch that could cost much less than similarly rated SiC power switches. The findings could lead to early applications in the power industry, especially in power converters like medium voltage drives, solid state transformers and high voltage transmissions and circuit breakers.
Wide bandgap semiconductors, such as SiC, show tremendous potential for use in medium- and high-voltage power devices because of their capability to work more efficiently at higher voltages. Currently though, their high cost impedes their widespread adoption over the prevailing workhorse and industry standard – insulated-gate bipolar transistors (IGBT) made from silicon – which generally work well but incur large energy losses when they are turned on and off.
The new SiC power switch, however, could cost approximately one-half the estimated cost of conventional high voltage SiC solutions, say Alex Huang and Xiaoqing Song, researchers at NC State’s FREEDM Systems Center, a National Science Foundation-funded engineering research center. Besides the lower cost, the high-power switch maintains the SiC device’s high efficiency and high switching speed characteristics. In other words, it doesn’t lose as much energy when it is turned on or off.
The power switch, called the FREEDM Super-Cascode, combines 12 smaller SiC power devices in series to reach a power rating of 15 kilovolts (kV) and 40 amps (A). It requires only one gate signal to turn it on and off, making it simple to implement and less complicated than IGBT series connection-based solutions. The power switch is also able to operate over a wide range of temperatures and frequencies due to its proficiency in heat dissipation, a critical factor in power devices.
“Today, there is no high voltage SiC device commercially available at voltage higher than 1.7 kV,” said Huang, Progress Energy Distinguished Professor and the founding director of the FREEDM Systems Center. “The FREEDM Super-Cascode solution paves the way for power switches to be developed in large quantities with breakdown voltages from 2.4 kV to 15 kV.”
Researchers from North Carolina State University and the Chinese Academy of Sciences have created an efficient, semi-printed plastic solar cell without the use of environmentally hazardous halogen solvents. These solar cells can be manufactured at room temperature, which has implications for large-scale commercial production.
Plastic solar cells, or organic photovoltaics, are popular because they are lightweight, flexible, transparent and inexpensive to manufacture, making them useful in multiple applications. Unfortunately, the halogen-containing solvents used in their manufacture are an obstacle to large-scale commercialization. These solvents are key to making sure that the solar cell’s morphology, or structure, maximizes its energy efficiency; however, they are environmentally hazardous. Additionally, the use of these harsh chemicals requires a controlled environment, which adds to production costs.
Long Ye, a postdoctoral research scholar in physics at NC State and lead author of a paper describing the work, wanted to find out if nontoxic solvents could provide equally efficient morphology in the manufacturing process. Ye and his colleagues developed a proof of concept semi-printed plastic solar cell that utilized o-methylanisole (o-MA) as the solvent. O-MA is a commonly used flavoring agent in foods, and is nontoxic to humans.
The researchers used soft X-ray techniques to study the morphology of their solar cell. They found that the o-MA based solar cell had similar morphology, crystalline features and device performance to those produced by halogenated solvents. The solar cell’s overall efficiency rating was around 8.4 percent. Furthermore, their cell could be produced via blade coating at ambient, or room temperature. Blade coating is a process that uses a glass blade to spread a thin layer of the photovoltaic film onto either a rigid or flexible substrate, and the process is compatible with large-scale commercial manufacturing.
“Two of the key requirements for mass producing these solar cells are that the cells can be produced in the open air environment and that the process doesn’t pose health or environmental hazards,” Ye says. “Hopefully this work can help pave the way for printing solar cells in ambient air.”
Learn more: Food Additive Key to Environmentally Friendly, Efficient, Plastic Solar Cells
Researchers at North Carolina State University have developed new, nonlinear, chaos-based integrated circuits that enable computer chips to perform multiple functions with fewer transistors. These integrated circuits can be manufactured with “off the shelf” fabrication processes and could lead to novel computer architectures that do more with less circuitry and fewer transistors.
Moore’s law states that the number of transistors on an integrated circuit will double every two years in order to keep up with processing demands. Previously this goal has been addressed by shrinking the size of individual transistors so that more could be added to the chip. However, that solution is quickly becoming untenable, and the semiconductor industry is looking for new ways to create better computer chips.
“We’re reaching the limits of physics in terms of transistor size, so we need a new way to enhance the performance of microprocessors,” says Behnam Kia, senior research scholar in physics at NC State and lead author of a paper describing the work. “We propose utilizing chaos theory – the system’s own nonlinearity – to enable transistor circuits to be programmed to perform different tasks. A very simple nonlinear transistor circuit contains very rich patterns. Different patterns that represent different functions coexist within the nonlinear dynamics of the system, and they are selectable. We utilize these dynamics-level behaviors to perform different processing tasks using the same circuit. As a result we can get more out of less.”
Kia and NC State colleague William Ditto, professor of physics and dean of the College of Sciences, worked on the conception, design, development and fabrication of an integrated circuit chip that contains working nonlinear circuits to perform multiple different digital computations.
Traditionally, transistor-based circuits perform one task each. Computer processors operate by routing each instruction and its operands to the appropriate transistor circuit on the integrated circuit that implements that specific instruction. In Kia’s design, the transistor circuit can be programmed to implement different instructions by morphing between different operations and functions.
“In current processors you don’t utilize all the circuitry on the processor all the time, which is wasteful,” Kia says. “Our design allows the circuit to be rapidly morphed and reconfigured to perform a desired digital function in each clock cycle. The heart of the design is an analog nonlinear circuit, but the interface is fully digital, enabling the circuit to operate as a fully morphable digital circuit that can be easily connected to the other digital systems.”
The researchers have produced an alternative approach for computing that is compatible with existing technology and utilizes the same fabrication process and CAD tools as existing computer chips, which could aid commercial adoption.
“We believe that this chip will help solve the challenges of demands for more processing power from fewer transistors,” Kia says. “The potential of 100 morphable nonlinear chaos-based circuits doing work equivalent to 100 thousand circuits, or of 100 million transistors doing work equivalent to three billion transistors holds promise for extending Moore’s law – not through doubling the number of transistors every two years but through increasing what transistors are capable of when combined in nonlinear and chaotic circuits.”
“We are nearing commercial size and power and ease of programming in our evolving designs that could well be of significant commercial relevance within a few months with our three month design/fabrication cycle of improvements and implementations,” Ditto says.
Materials researchers at North Carolina State University have developed a technique that allows them to integrate graphene, graphene oxide (GO) and reduced graphene oxide (rGO) onto silicon substrates at room temperature by using nanosecond pulsed laser annealing. The advance raises the possibility of creating new electronic devices, and the researchers are already planning to use the technique to create smart biomedical sensors.
In the new technique, researchers start with a silicon substrate. They top that with a layer of single-crystal titanium nitride, using domain matching epitaxy to ensure the crystalline structure of the titanium nitride is aligned with the structure of the silicon. Researchers then place a layer of copper-carbon (Cu-2.0atomic percent C) alloy on top of the titanium nitride, again using domain matching epitaxy. Finally, the researchers melt the surface of the alloy with nanosecond laser pulses, which pulls carbon to the surface.
If the process is done in a vacuum, the carbon forms on the surface as graphene; if it is done in oxygen, it forms GO; and if done in a humid atmosphere followed by a vacuum, it forms as rGO. In all three cases, the carbon’s crystalline structure is aligned with the underlying copper-carbon alloy.
“We can control whether the carbon forms one or two monolayers on the surface of the material by manipulating the intensity of the laser and the depth of the melting,” says Jay Narayan, the John C. Fan Distinguished Chair Professor of Materials Science and Engineering at NC State and senior author of a paper describing the work.
“The process can easily be scaled up,” Narayan says. “We’ve made wafers that are two inches square, and could easily make them much larger, using lasers with higher Hertz. And this is all done at room temperature, which drives down the cost.”
Graphene is an excellent conductor, but it cannot be used as a semiconductor. However, rGO is a semiconductor material, which can be used to make electronic devices such as integrated smart sensors and optic-electronic devices.
“We have already patented the technique and are planning to use it to develop smart biomedical sensors integrated with computer chips,” Narayan says.
Researchers at North Carolina State University have developed a model that allows antenna designers to identify efficient configurations for antenna designs in minutes, rather than days. The model is designed to expedite development of next generation “multi-input, multi-output” (MIMO) antennas, which allow devices to get more use out of the available bandwidth.
“Our model produces nearly optimal results, and should save designers an enormous amount of time in reaching results that can be used to create prototypes or that could be refined using conventional modeling techniques,” says Jacob Adams, an assistant professor of electrical and computer engineering at NC State and senior author of a paper on the work.
In a MIMO system, multiple transmitters can send data on the same frequency but along different spatial paths. Multiple receivers can distinguish between those multiple streams of data based on the uniqueness of the paths that the radio waves take to the multiple receivers. This type of system requires MIMO antennas which are often planar, or flat, and are found in everything from smartphones to satellite arrays. The point at which a transmitter and receiver connect to the antenna is called a port. If a MIMO system is using two ports, it can double the amount of data being transmitted. And you can achieve greater benefits by using more ports.
This is important because competition for available bandwidth is fierce. Commercial and military communication services must broadcast and receive information via the finite spectrum of radio frequencies, even as consumers are calling for faster download speeds for their personal devices.