Science

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Large Asteroid to Safely Pass Earth on Sept. 1

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Asteroid Florence, a large near-Earth asteroid, will pass safely by Earth on Sept. 1, 2017, at a distance of about 4.4 million miles.

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Gold shines through properties of nano biosensors: Researchers discover that fluorescence in ligand-protected gold nanoclusters is an intrinsic property of the gold particles themselves

With their remarkable electrical and optical properties, along with biocompatibility, photostability and chemical stability, gold nanoclusters are gaining a foothold in a number of research areas, particularly in biosensing and biolabeling.

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The researchers used Au20, gold nanoparticles with a tetrahedral structure, to show that fluorescence in ligand-protected gold clusters is an intrinsic property of the gold nanoparticles themselves.

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Candy cane supercapacitor could enable fast charging of mobile phones

Supercapacitors promise recharging of phones and other devices in seconds and minutes as opposed to hours for batteries. But current technologies are not usually flexible, have insufficient capacities, and for many their performance quickly degrades with charging cycles.

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Supercapacitors promise recharging of phones and other devices in seconds and minutes as opposed to hours for batteries. But current technologies are not usually flexible, have insufficient capacities, and for many their performance quickly degrades with charging cycles.

http://www.nanotech-now.com/news.cgi?story_id=54680

內湖 2021 陳鵬程

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Supermassive Black Holes Feed on Cosmic Jellyfish

ESO’s MUSE instrument on the VLT discovers new way to fuel black holes

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Observations of “Jellyfish galaxies” with ESO’s Very Large Telescope have revealed a previously unknown way to fuel supermassive black holes. It seems the mechanism that produces the tentacles of gas and newborn stars that give these galaxies their nickname also makes it possible for the gas to reach the central regions of the galaxies, feeding the black hole that lurks in each of them and causing it to shine brilliantly.

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Cassini Prepares to Say Goodbye to a True Titan

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These two views of Saturn's moon Titan exemplify how NASA's Cassini spacecraft has revealed the surface of this fascinating world.

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From hot to cold: How to move objects at the nanoscale: Moving a single gold nanocluster on a graphene membrane, thanks to a thermal gradient applied to the borders: a new study sheds light on the physical mechanisms driving this phenomenon

To move a nanoparticle on the surface of a graphene sheet, you won't need a "nano-arm": by applying a temperature difference at the ends of the membrane, the nanocluster laying on it will drift from the hot region to the cold one. In addition, contrary to the laws ruling the world at the macroscale, the force acting on the particle -- the so-called thermophoretic force -- should not decrease as the sheet length rises, sporting a so-called ballistic behavior, same as a bullet in a gun barrel. In fact, simulations show that vertical thermal oscillations of the graphene membrane flow ballistically from hot to cold, providing a push to the object. Yet, these vertical waves, known as flexural phonons, should not be able to impress any lateral shift to an object. Nevertheless, computer simulations show that they do push the nanocluster in the same way a surfboard is taken to shore by ocean waves. And, of course within limits, no matter how far away the wave came from. These theoretical predictions could be of great interest in the frame of manipulating materials at the nanoscale, in view of potential technological applications.

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The theoretical predictions of these study could be of great interest in the frame of manipulating materials at the nanoscale for technological applications.

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2-faced 2-D material is a first at Rice: Rice University materials scientists create flat sandwich of sulfur, molybdenum and selenium

Like a sandwich with wheat on the bottom and rye on the top, Rice University scientists have cooked up a tasty new twist on two-dimensional materials.

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Rice University materials scientists replace all the atoms on top of a three-layer, two-dimensional crystal to make a transition-metal dichalcogenide with sulfur, molybdenum and selenium.

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Five Berkeley Lab Researchers Receive DOE Early Career Research Awards

Five scientists at Lawrence Berkeley National Laboratory (Berkeley Lab) have been selected by the U.S. Department of Energy’s (DOE’s) Office of Science to receive significant funding for research through its Early Career Research Program.

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NASA's Voyager Spacecraft Still Reaching for the Stars After 40 Years

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An artist concept depicting one of the twin Voyager spacecraft. Humanity's farthest and longest-lived spacecraft are celebrating 40 years in August and September 2017.

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High-speed FM-AFM and simulation reveal atomistic dissolution processes of calcite in water

Calcite is one of the most abundant components of the Earth crust, the outer-most layer of the Earth, constituting as the largest carbon reservoir in the global carbon cycle in nature. Thus, large-scale dissolution of calcite would give an enormous impact on the weather, geography, aquatic environment and so on; more specifically, for example, changes in the carbon dioxide concentration of the air and the acidity of the ocean. Recently, the dissolution mechamism of calcite attracts much attention because of its importance in geologic carbon sequestration (GCS) technology to capture carbon dioxide from the air and to store it underground. In order to precisely predict such a large-scale and long-term phenomenon, the dissolution mechanism of calcite should be understood at an atomic level in a precise manner.

(a) Atomistic model of calcite surface. (b) The dissolution processes of calcite surface in water observed with high-speed FM-AFM. It is observed that the step is moving from lower-right to upper-left. Along the step is also seen the transition region. (c) Averaged height profile measured along the line PQ indicated in (b). The height of a monolayer step is ~0.3 nm, but that of the transition region is smaller. A terrace described in the Figure indicates a flat area at the atomic level on the crystal surface. The upper terrace is higher by one monolayer of CaCO3 than the lower terrace.