![]() Taking a photo of the sun with a standard camera show a disk with no features and a yellowish color. The part of the solar atmosphere that can be seen from the ground during a total solar eclipse. SDO has recorded hundreds of millions of images from the Sun, showing us different views of the visible surface all the way out to the extended part of the Sun’s atmosphere called the corona. SDO views the sun in 13 different ways, using two different onboard instruments. Solar Dynamics Observatory (SDO) & the Sun’s Cycle SDO views the Sun in 10 different wavelengths of light covering the visible, ultraviolet, and extreme ultraviolet bands of the light spectrum. The research was funded by the National Science Foundation under a CAREER award to Luo, and by the New York State Foundation for Science, Technology and Innovation.These forever stamps highlight amazing views of the Sun from a spacecraft that has been monitoring the Sun 24-hours a day for more than a decade. This means, the researchers say, that nanoscale superlattice features - currently possible only with expensive, specialized equipment - can be made in an inexpensive way. As they dry, droplets shrink to create wires and other shapes measured in nanometers from a mold measured in microns. Microscopic holes and channels in the underside of the mold effectively "stamp" the desired shapes on the fluid. The next step is to press down a silicone rubber mold onto a thin layer of the solution on a silicon substrate. Metal superlattices have applications in computer memory and photonics and have unique properties in electronic circuits. Adjusting the DNA lengths can precisely control the distance between the particles to make them assemble into orderly arrays called superlattices, rather than clumping together at random. The DNA molecules extend out from the particles like hairs and, as the water evaporates, entangle the particles with one another. A second innovation in the Cornell process is to use single chains of synthetic DNA as the ligand. To suspend metal particles in water, the researchers coated them with a "ligand" that adheres to the metal and to water. They began with gold nanoparticles about 12 nanometers in diameter suspended in water. ![]() They also assembled arrays of single salt crystals, suggesting that any material capable of crystallization could be manipulated by the process. In addition to metal nanoparticles, the process could be applied to quantum dots, magnetic spheres and other nanoparticles, they said. To demonstrate the process, the researchers assembled gold nanoparticles into nanoscale wires, disks, squares, triangles and "corrals" (spaces enclosed by nanowires), and demonstrated that their nanowires could be connected to microfabricated electrodes, and through them to other circuitry. Their work is described in the online edition of the journal Nature Nanotechnology and in the October 2008 print issue. "You can in principle build almost any types of architectures you want at nanoscale," reported Dan Luo, Cornell associate professor of biological and environmental engineering, postdoctoral researcher Wenlong Cheng and colleagues. The process is guided by molds that "stamp" the desired structures. By manipulating the way tiny droplets of fluid dry, Cornell researchers have created an innovative way to make and pattern nanoscale wires and other devices that ordinarily can be made only with expensive lithographic tools.
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