October 2005
Digital heat flow, CSI-style tricorder, and electrifying images of butterfly wings at AVS Science & Technology International Symposium
AVS International Symposium to feature cutting-edge science & technology
October 6, 2005 --New York, NY-- AVS--The Science & Technology Society will hold its 52nd International Symposium & Exhibition from October 30-November 4, 2005 at the Hynes Convention Center (900 Boylston Street) in Boston, MA. The Symposium will feature over 1300 papers and posters, with at least 3,000 expected attendees.
SUMMARY
Some news highlights include: the first observation of "digital" heat flow, a portable contaminant detector that advances CSI-style technology to near-Star-Trek levels, and stunning images of butterfly wings and other biological materials using a new microscopy technique that images long-known but seldom-exploited electromechanical properties of tissue.
COVERING THE MEETING
The AVS Pressroom will be located in Room 205 of the Hynes Convention Center. The room will be open on Monday-Thursday, October 31-November 3, 2005, from 8 a.m. to 5 p.m. The pressroom phone number will be 617-954-2958. Reporters can fill out a form to receive a complimentary registration badge by visiting http://www2.avs.org/symposium/boston/pressroom/regform.html. Please make your request for a registration badge by October 24 if possible.
Even if you can't attend the meeting, the AVS Symposium Web Pressroom (http://www2.avs.org/symposium/boston/pressroom.html) contains links to the meeting press releases, and will soon feature detailed lay-language versions of selected papers. In addition, the AVS Symposium home page (http://www2.avs.org/symposium/boston/default.asp) contains links to the full program as well as other meeting information. For assistance in contacting researchers and setting up interviews, please do not hesitate to contact the AIP and AVS staff listed at the top of the news release.
PRESS LUNCHEON
On Monday, October 31, from 1-2 PM, there will be a meeting press luncheon highlighting some of the most exciting news coming out of the meeting. Topics include first observation of "digital" heat flow (Marc Bockrath, Caltech); imaging the electromechanical properties of biological tissue (Sergei Kalinin, Oak Ridge); weighing DNA and other new uses of nanomachines (Harold Craighead, Cornell). The luncheon will take place in the Exhibitor Workshop area of Exhibit Hall D of the Hynes Convention Center. Please RSVP Ben Stein ([email protected]) or Della Miller ([email protected]) if you'd like to attend.
PLENARY LECTURE--THE CROSSBAR ARCHITECTURE FOR NANOELECTRONICS
On Monday, October 31, at 12 PM, R. Stanley Williams, HP Senior Fellow of Hewlett-Packard Laboratories in Palo Alto, CA, will present a plenary lecture entitled "The Crossbar Architecture for Nanoelectronics." This year, Williams and his colleagues have presented a series of papers outlining a nanometer-scale alternative to the transistor, called the "crossbar latch." Made up of criss-crossing ultrathin wires sandwiching electrically switchable material, crossbar latches can perform all the functions of a transistor but at a hundredfold smaller size scale. Potentially ready for commercialization in 5 to 20 years, the crossbar latch is designed to function properly even with the existence of tiny nanoscale manufacturing defects in the material and does not require a radical change in chip manufacturing processes (see http://www.hpl.hp.com/news/2005/jan-mar/crossbar.html for more information).
HIGHLIGHTS
Here is a sampling of some of the many intriguing talks that will be presented at the symposium.
1. MICROPLASMA-ON-A-CHIP ADVANCES CSI TECHNOLOGY TO STAR-TREK LEVELS
2. THE FIRST OBSERVATION OF DIGITAL HEAT FLOW
3. ELECTRIFYING BUTTERFLY WING PICTURES AT THE NANOSCALE
4. HYDROGEN-AIR MIXTURE EASIER TO IGNITE THAN PREVIOUSLY REALIZED
5. FINE-TUNING BIOSENSORS
6. OTHER HIGHLIGHTS
1. MICROPLASMA-ON-A-CHIP ADVANCES CSI TECHNOLOGY TO STAR-TREK LEVELS
Bringing a real-world technique mentioned on the TV drama CSI out of the forensics laboratory, Northeastern University researchers (contact Jeffrey Hopwood, [email protected]) have built a portable, cell-phone-sized "microplasma" device, reminiscent of the tricorder in Star Trek, that can quickly detect tiny amounts of contaminants in the air. Slated to be commercially available in the next year, the device can potentially identify atmospheric contaminants from natural disasters, industrial accidents, or intentional attacks. Using some of the same technology from cell phones and plasma televisions, the portable device is a much smaller, cheaper, and lighter unit for performing standard forms of chemical analysis than presently required bulky laboratory equipment outputting thousands of watts of power.
The Northeastern device converts air samples into very small plasmas (electrically charged gases) with microscopic dimensions. (Such "microplasmas" make up the picture elements in plasma TV sets.) By using a device called a spectrometer to measure the unique set of colors (wavelengths) that are emitted by the electrically charged atoms and molecules in the microplasma, researchers can determine the type and amount of contamination in a gas sample. This method of chemical analysis, available for decades, goes by names such as ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry ) which has been mentioned on CSI.
In order to make portable, inexpensive devices that can perform this analysis, Northeastern researchers employed the methods used in making computer circuit boards and computer chips. In their design, a cell-phone chip supplies the radio-wave energy needed to create the microplasma. The radio waves that a cell phone normally beams to the outside world are instead concentrated inside the unit, into a microscopic gap in a thin ring of gold. The gap is only 25 microns wide - about one-half the width of a human hair. With all of this energy concentrated in such a small region, the gases in the gap become ionized as the electrons are stripped from the gas atoms. By monitoring the light emission from the plasma, contamination in the air can be detected using this hand-held device, currently being commercialized by the company Verionix. (Paper PS-WeA9, Wednesday, November 2, 2005, 4:40pm, Room 302)
**For more information and images, a lay-language paper by Jeffrey Hopwood will be available later today at http://www2.avs.org/symposium/boston/pressroom.html
2. THE FIRST OBSERVATION OF DIGITAL HEAT FLOW in a nanostructure at ambient conditions has been made using carbon nanotubes suspended between two electrodes. A new experiment carried out at Caltech furthers the effort to employ nanotubes as a conduit for removing unwanted heat from microcircuits. Carbon nanotubes, nanometer-wide cylinders made from rolled-up sheets of graphite, have a versatile array of mechanical, electrical, and magnetic properties. Their thermal properties should be just as valuable. Because phonons (the particle manifestations of heat flow) can move so freely in nanotubes, even ballistically (meaning that they refrain from scattering and travel in straight lines), the flow of heat in nanotubes should have quantum properties. Indeed, Caltech scientist Marc Bockrath ([email protected]) and his colleagues have observed that heat conductivity in nanotubes can reach an ultimate limit to heat flow where heat conduction occurs in multiples of a quantum unit of heat flow. Phonons seem to move nearly as far as hundreds of nanometers (a long distance for nanoscopically sized objects) even at temperatures of 600 C. The phonons' mean-free path (the average distance they travel between collisions) should be even larger at room temperature. This, says Bockrath, underscores the fantastic potential of nanotubes as thermal conduits. (Paper NS-ThM4, Thursday, November 3, 2005, 9:20 AM, Room 210)
3. ELECTRIFYING BUTTERFLY WING PICTURES AT THE NANOSCALE
Applying state-of-the-art technology to a seldom-exploited electromechanical property in biomolecules, Sergei Kalinin ([email protected]) and Brian Rodriguez of Oak Ridge National Laboratory and Alexei Gruverman of North Carolina State University have demonstrated a nanometer-scale version of Galvani's experiment, in which 18th-century Italian physician Luigi Galvani caused a frog's muscle to contract when he touched it with an electrically charged metal scalpel. The new, 21st-century demonstration promises to yield a host of previously unknown information in a variety of biological structures including cartilage, teeth, and even butterfly wings.
Employing a technique named Piezoresponse Force Microscopy (PFM), Kalinin and colleagues sent an electrical voltage through a tiny, nanometer-sized tip to induce mechanical motion along various points in a biological sample, such as a single fibril of the protein collagen. The electromechanical response at various points of the sample enabled the researchers to build up images of the collagen fibrils, with details less than 10 nanometers in size. This resolution surpasses the level of detail that can be gleaned on those biostructures by ordinary scanning-probe and electron microscopes.
The PFM technique exploits the well-known but infrequently used fact that many biomolecules, especially those that are made of groups of proteins, are piezoelectric, or undergo mechanical deformations in the presence of an external electric field. The researchers have used the PFM technique to produce images of cartilage as well as enamel and dentin (found inside teeth). Besides providing images of biostructures on a nanometer scale, the new technique yields information about the electromechanical properties and molecular orientation of biological tissue. In recent work, the researchers even found unexpected piezoelectric properties in butterfly wings which enabled them to yield molecular-level images of wing structures. (Paper NS-WeM3, Wednesday, November 2, 2005, 9:00am, Room 210)
** For more information and images, a lay-language paper by Sergei Kalinin will be available soon at http://www2.avs.org/symposium/boston/pressroom.html
4. HYDROGEN-AIR MIXTURE EASIER TO IGNITE THAN PREVIOUSLY REALIZED
In a surprising result, researchers have discovered that igniting mixtures of hydrogen (H) and air at sub-atmospheric pressures can require much less energy than expected, as low as 20 microJoules, or several thousand times lower than the energy powering a pocket flashlight. While a hydrogen explosion requires a minimum concentration of H gas in the air (at least 4% by volume), the researchers hope that these results will further encourage safeguards for the gas, which is used in industrial processes and potentially as the fuel in future-generation hydrogen cars. The explosive nature of a hydrogen-and-air mixture is well known at atmospheric pressure; however very little data exists on hydrogen-air mixtures at sub-atmospheric pressures.
These pressures are of interest to Trevor Jones ([email protected]) and his colleagues, who work at the Souderton, Pennsylvania location of Solar Atmospheres, Inc., a company which treats and enhances metals by heating them in hydrogen gas at atmospheric and sub-atmospheric pressures. Jones and his colleagues sought to establish the explosive limits of hydrogen-air ratios at several different pressures ranging from atmospheric pressure to near outer-space vacuum. The experiment took the test one step further by actually igniting these mixtures as a controlled explosion. The tests were conducted in a small test vessel equipped with a spring-loaded lid that "blows" off to relieve the air/hydrogen explosive force. The researchers determined the various pressures and hydrogen concentration necessary to ignite the gas with a 5000-volt, 200-Watt spark (which delivered many times more than 20 microjoules of energy).
The researchers hope that this information will bring about an added "respect" for handling the gas properly and provide helpful safety information to others in the field and to the general public. (Paper VT-WeA9, Wednesday, November 2, 2005, 4:40pm, Room 201)
** For more information and images, a lay-language paper by Trevor Jones will be available later today at http://www2.avs.org/symposium/boston/pressroom.html
5. FINE-TUNING RESONANT BIOSENSORS
Nanoelectromechanical systems (NEMS) technology---the shrinking of lithographically prepared labs-on-a-chip---are especially valuable for biosensing of single molecules. Using such small detectors makes analysis or detection faster, and needs only tiny amounts of sample material or other reagents. But the main motivation is the much greater sensitivity in locating and identifying single bio-molecules by measuring their masses. A typical sensor consists of an oscillating cantilever so small in size and mass that even if a single molecule were to alight on it, the cantilever's resonant frequency (the vibration rate it maintains once set in motion) would shift measurably.
B. Rob Ilic ([email protected]), the user program manager at Cornell's Nanoscale Facility, will report on new efforts to optimize the NEMS biosensor, especially by moving the light source (a diode laser) which drives the oscillator further away from the point at which the cantilever is attached. He will also summarize new efforts to use the sensitive mass detection method to catalog the contents of strands of DNA with lengths of about 1500 base pairs.
(Paper MN-MoA2, Monday, October 31, 2005, 2:20pm)
6. OTHER HIGHLIGHTS AT THE SYMPOSIUM include talks on sustainable energy (EN-SuA1) and green semiconductor technology (TS-TuM7); the "nanogate," a device for creating very small flows of gas (VT-WeM3); applying existing chemistry techniques to surmount a technical obstacle for making smaller components in next-generation computer chips (MS-TuA3); creating synthetic sugar surfaces with the potential of recognizing specific bacteria (BI2-ThM9); a "spinning wall" that rotates 200,000 times a second to study interactions between a plasma and a solid surface (PS-ThM2); Shaken, Not Stirred: A New Approach to Biomagnetic Sensing (MI+BI-FrM7); controlling cell position in biodegradable scaffolds intended to grow artificial tissue (MN-TuM5); machines made of DNA (DN+BI-MoM3); next-generation semiconductor devices made of carbon nanotubes (MS+MN+NS-WeM3); self-assembly activated by molecular motors(NS2-MoA9); the promises and challenges of using hydrogen as an energy carrier (TS-TuM5); new advances in optical imaging of living cells (BP-SuA5); and Cooper-Pair molasses (MN-TuM5).
ABOUT AVS--THE SCIENCE & TECHNOLOGY SOCIETY
AVS is a not-for-profit professional society that promotes communication between academia, government laboratories, and industry for the purpose of sharing research and development findings over a broad range of technologically relevant topics.
Originally known as the American Vacuum Society, AVS was founded in 1953 as a forum to discuss problems and applications of high-vacuum technology, the process of making pristine environments almost completely devoid of air and other gases. Today, AVS papers showcase experiments not only in vacuums but also in many other "controlled environments."
These controlled environments include so-called "underwater surfaces," or carefully prepared samples immersed in liquids, which are the natural environment for many biological structures. In addition, AVS members study and manipulate the boundaries or "interfaces" between liquids and solids to make state-of-the-art fuel cells and better batteries.
Crucial processes for making computer chips, such as chemical vapor deposition, are now being done at atmospheric pressure where vacuum pressure was once necessary. Add to the list atomic- and molecular-scale microscopy, which is routinely done in air and liquid, and you'll get a sense of the many controlled environments that AVS members create and study for a whole host of applications over the entire spectrum of science and technology.