Nature Nanotechnology, July 4, 2010:WhenSir William Crookesdeveloped a four-vaned radiometer, also known as thelight-mill, in 1873, it was believed that this device confirmed the existence of linear momentum carried by photons, as predicted by Maxwell's equations. Although Reynolds later proved that the torque on the radiometer was caused by thermal transpiration, researchers continued to search for ways to take advantage of the momentum of photons and to use it for generating rotational forces. The ability to provide rotational force at the nanoscale could open up a range of applications in physics, biology and chemistry, including DNA unfolding and sequencing and nanoelectromechanical systems. Here, we demonstrate a nanoscaleplasmonicstructure that can, when illuminated with linearly polarized light, generate a rotational force that is capable of rotating a silica microdisk that is 4,000 times larger in volume. Furthermore, we can control the rotation velocity and direction by varying the wavelength of the incident light to excite different plasmonic modes - Light-driven nanoscale plasmonic motors
American Chemical Society, July 23, 2010:We describe the motion of self-propelled hybrid microengines containing catalase enzyme covalently bound to the cavity of rolled-up microtubes. The high efficiency of these hybrid microengines allows them to move at a very low concentration of peroxide fuel. The dynamics of the catalytic engines is mediated by the generation of front-side bubbles, which increase the drag force and make them turn. The specific modification of the inner layer of microtubes with biomolecules can lead to other configurations to generate motion from different chemical fuels - Dynamics of Biocatalytic Microengines Mediated by Variable Friction Control
A tiny tube powered by bubbles of oxygen generated by degrading hydrogen peroxide shows its power by pushing around a stack of polystyrene beads. Taken from A Solovev et al, Adv. Funct. Mater. 2010,http://dx.doi.org/10.1002/adfm.200902376
Børge Svanstrøm Amundsen
"All the reasons which make the initiation of physical force an evil, make the retaliatory use of physical force a moral imperative" - Ayn Rand
National Institute of Standards and Technology, August 31, 2010:Physicists at the National Institute of Standards and Technology (NIST) have used a small crystal of ions (electrically charged atoms) to detect forces at the scale of yoctonewtons. Measurements of slight forces—one yoctonewton is equivalent to the weight of a single copper atom on Earth—can be useful in force microscopy, nanoscale science, and tests of fundamental physics theories. A newton is already a small unit: roughly the force of Earth's gravity on a small apple. A yoctonewton is one septillionth of a newton (yocto means 23 zeros after the decimal place, or 0.000000000000000000000001). Measurements of vanishingly small forces typically are made with tiny mechanical oscillators, which vibrate like guitar strings. The new NIST sensor,described in Nature Nanotechnology, is even more exotic—a flat crystal of about 60 beryllium ions trapped inside a vacuum chamber by electromagnetic fields and cooled to 500 millionths of a degree above absolute zero with an ultraviolet laser. The apparatus was developed over the past 15 years for experiments related to ion plasmas and quantum computing - Yikes! NIST Sensor Measures Yoctonewton Forces Fast
The NIST force sensor is a crystal of ions (charged atoms) trapped inside the upper region of the copper cylinder. A laser beam directed upward through the trap cools the ions. A force is applied in the form of oscillating electric field, and a detector (not shown) measures the light reflected off the ions.
Børge Svanstrøm Amundsen
"All the reasons which make the initiation of physical force an evil, make the retaliatory use of physical force a moral imperative" - Ayn Rand
Caltech, September 2, 2010:Researchers at Caltech have devised a new technique—using a sheet of carbon just one atom thick—to visualize the structure of molecules. The technique, which was used to obtain the first direct images of how water coats surfaces at room temperature, can also be used to image a potentially unlimited number of other molecules. Apaper describing the methodand the studies of water layers appears in the September 3 issue of the journal Science. Whereas the data from one molecule might reveal the gross structure, data from 10 will reveal finer features—and computationally assembling the data from 1,000 identical molecules might reveal every atomic nook and cranny - Caltech Chemists Develop Simple Technique to Visualize Atomic-Scale Structures
