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The flashback is due to the speed of today's underwater communication networks, which is comparable to the sluggish dial-up modems from America Online's heyday. The shortcoming hampers search-and-rescue operations, tsunami detection and other work. But that is changing due in part to University at Buffalo engineers who are developing hardware and software tools to help underwater telecommunication catch up to its over-the-air counterpart. Their work, including ongoing collaborations with Northeastern University, is described in a study - Software-Defined Underwater Acoustic Networks: Toward a High-Rate Real-Time Reconfigurable Modem - published in November in IEEE Communications Magazine. "The remarkable innovation and growth we've witnessed in land-based wireless communications has not yet occurred in underwater sensing networks, but we're starting to change that," says Dimitris Pados, PhD, Clifford C. Furnas Professor of Electrical Engineering in the School of Engineering and Applied Sciences at UB, a co-author of the study. The amount of data that can be reliably transmitted underwater is much lower compared to land-based wireless networks. This is because land-based networks rely on radio waves, which work well in the air, but not so much underwater. As a result, sound waves (such as the noises dolphins and whales make) are the best alternative for underwater communication. The trouble is that sound waves encounter such obstacles as path loss, delay and Doppler which limit their ability to transmit. Underwater communication is also hindered by the architecture of these systems, which lack standardization, are often proprietary and not energy-efficient.Pados and a team of researchers at UB are developing hardware and software -everything from modems that work underwater to open-architecture protocols - to address these issues. Of particular interest is merging a relatively new communication platform, software-defined radio, with underwater acoustic modems. Traditional radios, such as an AM/FM transmitter, operate in a limited bandwidth (in this case, AM and FM). The only way to pick up additional signals, such as sound waves, is to take the radio apart and rewire it. Software-defined radio makes this step unnecessary. Instead, the radio is capable via computer of shifting between different frequencies of the electromagnetic spectrum. It is, in other words, a "smart" radio. Applying software-defined radio to acoustic modems could vastly improve underwater data transmission rates. For example, in experiments last fall in Lake Erie, just south of Buffalo, New York, graduate students from UB proved that software-defined acoustic modems could boost data transmission rates by 10 times what today's commercial underwater modems are capable of. The potential applications for such technology includes: Explore further: New research suggests changes in underwater data communications

The Missouri S&T team has developed a microwave 3-D video camera that can be used for industrial inspection applications, security screening—and might even one day be used by first responders. Dr. Mohammad Tayeb Ghasr, assistant research professor at Missouri S&T, and Dr. Reza Zoughi, the Schlumberger Distinguished Professor of Electrical Engineering at Missouri S&T, are the lead researchers on the project. The real-time 3-D microwave camera prototype operates in the 20-30 gigahertz frequency range. "It's like an airport scanner but much smaller," Ghasr says. "It's portable, so it can be used on-site wherever it is needed." Unlike X-ray inspection systems that could be hazardous, the microwave camera uses low-power non-ionizing electromagnetic waves, which are safe. Given the relatively high and wide range of operating frequencies, it can produce high-resolution 3-D images. This, combined with fast electronics, enables data collection at a rate equivalent to 30 image frames per second, rendering it a real-time imaging system. The camera is ideal for inspection of composite structures that are increasingly used in the transportation, infrastructure, space, aerospace and other similar industries. Because microwave signals can penetrate non-metallic materials, this system is expected to find significant use in inspecting ceramics, fiberglass, plastics and high-density polyethylene pipes. The combination of portability, 3-D and real-time image production capabilities and low power consumption make it an ideal tool for high-throughput screening environments such as stadiums for contraband detection. In the future, Ghasr also sees its potential use by first responders, especially those dealing with burn victims. The microwave camera, when designed optimally, has the potential to diagnose the severity of a burn so medical personnel can apply the appropriate treatment quickly and safely. Also working on the project are Matthew Horst, a graduate student in the electrical and computer engineering department from Cape Girardeau, Missouri, who is a National Science Foundation (NSF) Graduate Fellow, and Matthew Dvorsky, a senior in electrical and computer engineering from Peoria, Illinois. The project was funded in part by the University of Missouri System Fast Track program that provides up to $50,000 per an accepted proposal. This program is intended to enhance the four universities' research discoveries by moving them down the commercial pipeline, toward patents and license agreements. Explore further: New research brings 'invisible' into view (w/ Video)

British researchers can possibly put an end to slow Internet with the creation of fiber optic cables that can send data 50,000 times faster than the current average broadband. Researchers at University College London's Optical Networks Group (ONG) explain that current commercial optical transmission systems are capable of receiving single channel data rates of up to 100 Gbps. However, the team is working with equipment that can manage data of up to 1 Tbps. Robert Maher, Ph.D., lead researcher at ONG - a research group within the Electronic & Electrical Engineering Department at UCL, says that they have achieved speeds of 1.125 Tbps, which is the highest throughput ever recorded using a single receiver. The high speed is meant to address the growing demand for fast Internet data. Maher, says that in comparison to the average broadband speed of 24 Mbps in the UK, the results are nearly 50,000 times faster. He also highlighted that this current Internet speed is already considered "superfast." The researchers say that the data rate will allow the download of the entire "Games of Thrones" series in a matter of seconds. Professor Polina Bayvel, who is the principal investigator of the UNLOC program at UCL, says that the result is actually a landmark for the technology industry. Such high-speed Internet will make a difference to the digital economy as well as lives of regular users. "This result is a milestone as it shows that terabit per second optical communications systems are possible in the quest to reach ever higher transmission capacities in optical fibers that carry the vast majority of all data generated or received," says Bayvel. The research team says that it benefited from the state-of-the-art lab facilities at the university while working on the project. For their experiment, 15 channels were combined and sent to one optical receiver. The grouping of the channels is believed to be the next-generation step in achieving high-capacity communication systems. The study involved connecting the receiver and transmitter directly to achieve high speed. Now, the researchers will start testing the system in long distance transmission, where optical signals may get distorted as they travel. Internet service providers are looking at ways to increase data speed and attract more customers. The day remains to be seen when users will be able to get data speeds of about 1 Tbps.

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Site: news.mit.edu

Today, computer chips are built by stacking layers of different materials and etching patterns into them. But in the latest issue of Advanced Materials, MIT researchers and their colleagues report the first chip-fabrication technique that enables significantly different materials to be deposited in the same layer. They also report that, using the technique, they have built chips with working versions of all the circuit components necessary to produce a general-purpose computer. The layers of material in the researchers’ experimental chip are extremely thin — between one and three atoms thick. Consequently, this work could abet efforts to manufacture thin, flexible, transparent computing devices, which could be laminated onto other materials. “The methodology is universal for many kinds of structures,” says Xi Ling, a postdoc in the Research Laboratory of Electronics and one of the paper’s first authors. “This offers us tremendous potential with numerous candidate materials for ultrathin circuit design.” The technique also has implications for the development of the ultralow-power, high-speed computing devices known as tunneling transistors and, potentially, for the integration of optical components into computer chips. “It’s a brand new structure, so we should expect some new physics there,” says Yuxuan Lin, a graduate student in electrical engineering and computer science and the paper’s other first author. Ling and Lin are joined on the paper by Mildred Dresselhaus, an Institute Professor emerita of physics and electrical engineering; Jing Kong, an ITT Career Development Professor of Electrical Engineering; Tomás Palacios, an associate professor of electrical engineering; and by another 10 MIT researchers and two more from Brookhaven National Laboratory and Taiwan’s National Tsing-Hua University. Computer chips are built from crystalline solids, materials whose atoms are arranged in a regular geometrical pattern known as a crystal lattice. Previously, only materials with closely matched lattices have been deposited laterally in the same layer of a chip. The researchers’ experimental chip, however, uses two materials with very different lattice sizes: molybdenum disulfide and graphene, which is a single-atom-thick layer of carbon. Moreover, the researchers’ fabrication technique generalizes to any material that, like molybdenum disulfide, combines elements from group six of the periodic table, such as chromium, molybdenum, and tungsten, and elements from group 16, such as sulfur, selenium, and tellurium. Many of these compounds are semiconductors — the type of material that underlies transistor design — and exhibit useful behavior in extremely thin layers. Graphene, which the researchers chose as their second material, has many remarkable properties. It’s the strongest known material, but it also has the highest known electron mobility, a measure of how rapidly electrons move through it. As such, it’s an excellent candidate for use in thin-film electronics or, indeed, in any nanoscale electronic devices. To assemble their laterally integrated circuits, the researchers first deposit a layer of graphene on a silicon substrate. Then they etch it away in the regions where they wish to deposit the molybdenum disulfide. Next, at one end of the substrate, they place a solid bar of a material known as PTAS. They heat the PTAS and flow a gas across it and across the substrate. The gas carries PTAS molecules with it, and they stick to the exposed silicon but not to the graphene. Wherever the PTAS molecules stick, they catalyze a reaction with another gas that causes a layer of molybdenum disulfide to form. In previous work, the researchers characterized a range of materials that promote the formation of crystals of other compounds, any of which could be plugged into the process. The new fabrication method could open the door to more powerful computing if it can be used to produce tunneling-transistor processors. Fundamentally, a transistor is a device that can be modulated to either allow a charge to cross a barrier or prohibit it from crossing. In a tunneling transistor, the charge crosses the barrier by means of a counterintuitive quantum-mechanical effect, in which an electron can be thought of as disappearing at one location and reappearing at another. These effects are subtle, so they’re more pronounced at extremely small scales, like the one- to three-atom thicknesses of the layers in the researchers’ experimental chip. And, because electron tunneling is immune to the thermal phenomena that limit the efficiency of conventional transistors, tunneling transistors can operate at very low power and could achieve much higher speeds. "This work is very exciting,” says Philip Kim, a physics professor at Harvard University. “The MIT team demonstrated that controlled stitching of two completely different, atomically thin 2-D materials is possible. The electrical properties of the resulting lateral heterostructures are very impressive."

News Article
Site: www.nanotech-now.com

Abstract: Healthcare practitioners may one day be able to physically screen for breast cancer using pressure-sensitive rubber gloves to detect tumors, owing to a transparent, bendable and sensitive pressure sensor newly developed by Japanese and American teams. Conventional pressure sensors are flexible enough to fit to soft surfaces such as human skin, but they cannot measure pressure changes accurately once they are twisted or wrinkled, making them unsuitable for use on complex and moving surfaces. Additionally, it is difficult to reduce them below 100 micrometers thickness because of limitations in current production methods. To address these issues, an international team of researchers led by Dr. Sungwon Lee and Professor Takao Someya of the University of Tokyo's Graduate School of Engineering has developed a nanofiber-type pressure sensor that can measure pressure distribution of rounded surfaces such as an inflated balloon and maintain its sensing accuracy even when bent over a radius of 80 micrometers, equivalent to just twice the width of a human hair. The sensor is roughly 8 micrometers thick and can measure the pressure in 144 locations at once. The device demonstrated in this study consists of organic transistors, electronic switches made from carbon and oxygen based organic materials, and a pressure sensitive nanofiber structure. Carbon nanotubes and graphene were added to an elastic polymer to create nanofibers with a diameter of 300 to 700 nanometers, which were then entangled with each other to form a transparent, thin and light porous structure. "We've also tested the performance of our pressure sensor with an artificial blood vessel and found that it could detect small pressure changes and speed of pressure propagation," says Lee. He continues, "Flexible electronics have great potential for implantable and wearable devices. I realized that many groups are developing flexible sensors that can measure pressure but none of them are suitable for measuring real objects since they are sensitive to distortion. That was my main motivation and I think we have proposed an effective solution to this problem." ### This work was conducted in collaboration with the research group of Professor Zhigang Suo at Harvard University, USA. Collaborating institutions Osaka University Harvard University, USA Funding Japan Science and Technology Agency (JST) Exploratory Research for Advanced Technology (ERATO) Someya Bio-Harmonized Electronics Project About University of Tokyo The University of Tokyo is Japan's leading university and one of the world's top research universities. The vast research output of some 6,000 researchers is published in the world's top journals across the arts and sciences. Our vibrant student body of around 15,000 undergraduate and 15,000 graduate students includes over 2,000 international students. Find out more at www.u-tokyo.ac.jp/en/ or follow us on Twitter at @UTokyo_News_en. For more information, please click Contacts: Research contact Professor Takao Someya Department of Electrical Engineering and Information Systems Graduate School of Engineering The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8656, Japan Tel: +81-3-5841-0411/6756 Fax: +81-3-5841-6709 Press officer contact Graduate School of Engineering Public Relations Office The University of Tokyo The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8656, Japan Tel: 03-5841-1790 Fax: 03-5841-0529 If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

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