Instantaneous and average energy dissipation distributions in the nanoscale due to short and long range interactions are described. We employ both a purely continuous and a semi-discrete approach to analyze the consequences of this distribution in terms of rate of heat generation, thermal flux, adhesion hysteresis, viscoelasticity and atomic dissipative processes. The effects of peak values are also discussed in terms of the validity of the use of average values of power and energy dissipation. Analytic expressions for the instantaneous power are also derived. We further provide a general expression to calculate the effective area of interaction for fundamental dissipative processes and relate it to the energy distribution profile in the interaction area. Finally, a semi-discrete approach to model and interpret atomic dissipative processes is proposed and shown to lead to realistic values for the atomic bond dissipation and viscoelastic atomic processes.
Posts Tagged ‘Nanoscale’
Energy dissipation distributions and dissipative atomic processes in amplitude modulation atomic force microscopy
Posted in Nanotechnology 
Tags: average-values, consequences, distribution, effective-area, Energy, further-provide, heat-generation, instantaneous, interaction, Nanoscale, Provide, the-interaction, the-nanoscale, thermal-flux, validity 
Comments OffHolographic 3-D Displays
. Applications like holographic TV have long been relegated as the next big thing in the distant future but a Belgium-based R&D lab for nanoelectronics has come up with a process that might bring holographic images closer to realtime. At Imec, their work involves creating moving pixels. They are constructing holographic displays by shining lasers on microelectromechanical systems ( MEMS ) platforms that can move up and down like small, reflective pistons. “Holographic visualization promises to offer a natural 3-D experience for multiple viewers, without the undesirable side-effects of current 3D stereoscopic visualization (uncomfortable glasses, strained eyes, fatiguing experience),” the company states. In their nanoscale system, they work with chips made by growing a layer of silicon oxide on to silicon wafer. They etch square patches of the silicon oxide. The result is a checkerboard-like pattern where etched-away pixels are nanometers lower than their neighbors. A reflective aluminum coating tops the chip. When laser light shines on the chip, it bounces off of the boundary between adjacent pixels at an angle. Diffracted light interferes constructively and destructively to create a 3-D picture where small mirrored platforms are moving up and down, many times a second, to create a moving projection. The process can also be described as the pixels closer to the light interfering with it one way and those further off, in another. The small distances between them generate the image that the eye sees. Imec hopes to construct the first, proof-of-concept moving structures by mid-2012. “Imec’s vision is to design the ultimate 3D display: a holographic display with a 60° diffraction angle and a high-definition visual experience,” they state. As such, Imec will have lots of company elsewhere in the race to iron out complexities of holographic imaging. According to reports throughout 2011, research teams aim to make the technology more of a reality than a wish-list item for consumers. The BBC R&D department has identified the work that broadcasters are doing across Europe, for example, in holographic TV. Engineers are also focused on research into 3-D holoscopy for the Internet and other 3-D applications. Researchers at MIT this year said they were closing in on holographic TV by building a system with a refresh rate of 15 frames per second. Also earlier this year, the Defense Advanced Research Projects Agency ( DARPA ) completed a five-year project called Urban Photonic Sandtable Display that creates realtime, color, 360-degree 3-D holographic displays. Read More Read More
Posted in Nanotechnology Tags: bbc, belgium-based, Defense, europe, Image, Internet, Light, Nanoscale, race, Research, Technology, technology-more, urban-photonic, Work Comments OffSmallshop
. “When I was student, I often heard, ‘We can do micromachining on any substance as long as it is silicon,’” says Murali M. Sundaram, Director of the University of Cincinnati Micro and Nano Manufacturing Laboratory. “But in the real world we need technologies to micromachine a variety of materials. This was my motivation to explore nontraditional and alternative processes.” Sundaram is exploring “alternative manufacturing processes,” which involves making materials at the nanoscale that don’t behave the same as they do at the macroscale. At the nanoscale, properties change. “Let’s say I want to write a program for a robot to move an object,” Sundaram said. “It should be simple. Locate the object, pick it up, move it drop it. However, at the nanoscale, the object will not drop. Gravity is not the major force at that scale.” Sundaram’s lab is engaged in an effort to find a nano equivalent to common machining techniques like drilling or grinding. There is no nano equivalent to sandpaper, but tiny particles of diamond can be bounced between an ultrasonically vibrated tool and the workpiece, generating holes smaller than 400 nanometers in diameter. Even here, scale makes a difference. “If I were to drill a hole in a sheet of metal, I would expect that hole to be there next week or next year,” Sundaram said. “If I make a hole just a few atoms wide, I will find that atoms gradually move into the open space.” Read More
Posted in Nanotechnology Tags: behave-the-same, bounced-between, director, macroscale, Manufacturing, Motivation, nano-equivalent, Nanoscale, sundaram, the-nanoscale, University, workpiece Comments OffFour-Wheeled Electric NanoCar
A nanoscale ‘car’ is the latest example of how nanoscale systems designed to imitate functions from the macroscopic world are leading to a new appreciation of the complexity that is needed to actuate motion at the limits of miniaturization. The nanocar was created by researchers from University of Groningen in The Netherlands, the Swiss Federal Laboratories for Materials Science and Technology, and the University of Zurich. The specially designed molecule has four motorized ‘wheels’. By depositing the molecules on a surface and providing them with sufficiently energetic electrons from the tip of a scanning tunneling microscope, the researchers were able to drive some of the molecules in a specific direction, much like a car with four-wheel drive. Previous examples of actuated single-molecule motion have been reported by others, but none with the complex action to continue moving in the same direction across a surface like the system devised, synthesized and operated by the team. In such work, the forces that dominate the macroscopic world around us, such as gravity, are less important than the forces that rule the nanoscale and biological worlds, such as van der Waals and capillary forces. Nevertheless, there are similarities between our everyday world and the nanoscale world: a car must have not only the ability to accelerate, but also brakes and traction; likewise, nanoscale actuated motion depends on balancing applied forces with those that hold structures in place. The researchers solved this problem, as others have, by balancing surface interactions and thermal energy with forces that can be applied through actuation, so that their molecules move only on stimulation, rather than by diffusion. Read More Paper Movie 1 (.mov) Movie 2 (.mov) Movie 3 (.mov) Movie 4 (.mov)
Posted in Nanotechnology Tags: complexity, Forces, hold-structures, like-the-system, macroscopic, Molecules, Nanoscale, nanoscale-world, Researchers, such-as-gravity, Swiss, swiss-federal, Technology Comments OffSynthesis, characterization, and finite size effects on electrical transport of nanoribbons of the charge density wave conductor NbSe 3
NbSe 3 exhibits remarkable anisotropy in most of its physical properties and has been a model system for studies of quasi-one-dimensional charge density wave (CDW) phenomena. Herein, we report the synthesis, characterization, and electrical transport of single-crystalline NbSe 3 nanoribbons by a facile one-step vapour transport process involving the transport of selenium powder onto a niobium foil substrate. Our investigations aid the understanding of the CDW nature of NbSe 3 and the growth process of the material. They also indicate that NbSe 3 nanoribbons have enhanced CDW properties compared to those of the bulk phase due to size confinement effects, thus expanding the search for new mesoscopic phenomena at the nanoscale level. Single nanoribbon measurements of the electrical resistance as a function of temperature show charge density wave transitions at 59 and 141 K. We also demonstrate significant enhancement in the depinning effect an…
Posted in Nanotechnology Tags: depinning, Electrical, facile-one-step, growth-process, Nanoscale, Search, Synthesis, the-depinning, the-electrical, the-transport Comments OffHigh performance under pressure
The accumulation of charge in certain materials in response to an applied mechanical stress was first discovered in 1880 by Pierre Curie and his brother Paul-Jacques. The effect, piezoelectricity, forms the basis of today’s microphones, quartz watches, and electronic components and constitutes an awesome scientific legacy. Research continues to develop further applications in a range of fields including imaging [1, 2], sensing [3] and, as reported in this issue of Nanotechnology , energy harvesting [4]. Piezoelectricity in biological tissue was first reported in 1941 [5]. More recently Majid Minary-Jolandan and Min-Feng Yu at the University of Illinois at Urbana-Champaign in the USA have studied the piezoelectric properties of collagen I [1]. Their observations support the nanoscale origin of piezoelectricity in bone and tendons and also imply the potential importance of the shear load transfer mechanism in mechanoelectric transduction in bone. Shear load transfer h…
Posted in Nanotechnology Tags: Applications, brother, develop-further, forms-the-basis, Issue, load-transfer, Nanoscale, Nanotechnology, pierre-curie, Piezoelectric, Potential, quartz-watches, shear, the-potential, University Comments OffNew Devices Via Sticky Graphene
Researchers at the University of Colorado at Boulder have discovered that graphene has surprisingly powerful adhesion qualities. According to the CU-Boulder team, experiments showed that the extreme flexibility of graphene allows it to conform to the topography of even the smoothest substrates. Graphene consists of a single layer of carbon atoms chemically bonded in a hexagonal chicken wire lattice. Its unique atomic structure could some day replace silicon as the basis of electronic devices and integrated circuits because of its remarkable electrical, mechanical and thermal properties, said Assistant Professor Scott Bunch, lead author of the study. “The real excitement for me is the possibility of creating new applications that exploit the remarkable flexibility and adhesive characteristics of graphene and devising unique experiments that can teach us more about the nanoscale properties of this amazing material,” Bunch said. Not only does graphene have the highest electrical and thermal conductivity among all materials known, but it has been shown to be the thinnest, stiffest and strongest material in the world, as well as being impermeable to all standard gases. It’s newly discovered adhesion properties can now be added to the list of the material’s seemingly contradictory qualities, said Bunch. The CU-Boulder team measured the adhesion energy of graphene sheets, ranging from one to five atomic layers, with a glass substrate, using a pressurized “blister test” to quantify the adhesion between graphene and glass plates. Adhesion energy describes how “sticky” two things are when placed together. Scotch tape is one example of a material with high adhesion; the gecko lizard, which seemingly defies gravity by scaling up vertical walls using adhesion between its feet and the wall, is another. Adhesion also can play a detrimental role, as in suspended micromechanical structures where adhesion can cause device failure or prolong the development of a technology, said Bunch. The CU research, the first direct experimental measurements of the adhesion of graphene nanostructures, showed that so-called van der Waals forces hold the graphene samples to the substrates and also hold together the individual graphene sheets in multilayer samples. The researchers found the adhesion energies between graphene and the glass substrate were several orders of magnitude larger than adhesion energies in typical micromechanical structures, an interaction they described as more liquid-like than solid-like, said Bunch. Read More Paper
Posted in Nanotechnology Tags: Adhesion, Development, glass-substrate, graphene-sheets, Individual, Nanoscale, possibility, real-excitement, remarkable, smoothest, Study, Substrates, the-possibility, topography, University Comments OffNew Method For Nanoribbon Production
Researchers from Ulm University, Germany, and the University of Nottingham, UK, have pioneered a new method for making molecules that could lead toward faster, smaller, and more powerful nanomaterials for computers and data storage devices. The team has demonstrated that carbon nanotubes can be used as nanoscale chemical reactors, wherein chemical reactions involving carbon and sulphur atoms held within a nanotube lead to the formation of a thin strip of carbon, known as a graphene nanoribbon, decorated with sulphur atoms around the edge. “Graphene nanoribbons possess a wealth of interesting physical properties making them more suitable for applications in electronic and spintronic devices than the parent material graphene,” says Dr Andrei Khlobystov. “Nanoribbons are very difficult to make but the Nottingham team’s strategy of confining chemical reactions at the nanoscale sparks spontaneous formation of these remarkable structures. The team has also discovered that nanoribbons — far from being simple flat and linear structures — possess an unprecedented helical twist that changes over time, giving scientists a way of controlling physical properties of the nanoribbon, such as electrical conductivity.” Devices based on nanoribbons could potentially be used as nano-switches, nano-actuators and nano-transistors integrated in computers or data storage devices. Read More Paper
Posted in Nanotechnology Tags: around-the-edge, formation, nanoribbon, Nanoscale, nottingham, parent-material, sulphur-atoms, the-nanoribbon, University, used-as-nano Comments OffMolecular information theory points to robust molecular communications
Those interested in issues of communication at the nanoscale will be interested to learn that the first volume of the new journal Nano Communication Networks , from Elsevier, edited by Ian Akyildiz, is available free of charge. The volume comprises four issues dated March through December of 2010. Just to pick one article out of dozens available, I found “ A brief review of molecular information theory ” by Thomas D. Schneider useful. His analysis, in terms of Claude Shannon’s information theory, of the control of gene expression by proteins binding to specific sites on DNA leads him to conclude that “we should be able to build molecular communications that are just as robust as our macroscopic ones.”
Posted in Nanotechnology Tags: Bionanotechnology, build-molecular, claude-shannon, Communication, Control, four-issues, molecular nanotechnology, Nanoscale, NANOTECH, our-macroscopic, specific-sites, the-nanoscale Comments OffTesting Nuclear Materials At The Nanoscale
The recent Fukushima disaster has raised renewed concerns about the safety of nuclear power, with many countries calling for stricter checks in nuclear power plants. Now, researchers at the Berkeley Lab, UC Berkeley, and the Los Alamos National Laboratory have developed a testing technique for irradiated materials that provides information on the strength of these materials on much larger length scales. The method could greatly reduce the amount of material required in tests and also help in the design of new, improved materials for nuclear applications. Peter Hosemann of UC Berkeley says that, by translating the nanoscale strength values obtained into bulk properties, the technique could help reactor designers find better materials for use as engineering components in nuclear plants. “And by using a smaller specimen for the tests, we limit any safety issues related to the handling of the test material,” he said. “We could potentially measure the exact properties of a material used in, say, a 40-year-old nuclear facility to make sure this structure lasts well into the future.” Read More Paper
Posted in Nanotechnology Tags: alamos-national, Berkeley, bulk-properties, Design, greatly-reduce, handling, Nanoscale, nuclear-power, peter-hosemann, safety, Strength, strength-values, Technique, these-materials Comments Off