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Feb 25, 2022

Visualization of the origin of magnetic forces

Posted by in categories: computing, particle physics, space

The joint development team of Professor Shibata (the University of Tokyo), JEOL Ltd. and Monash University succeeded in directly observing an atomic magnetic field, the origin of magnets (magnetic force), for the first time in the world. The observation was conducted using the newly developed Magnetic-field-free Atomic-Resolution STEM (MARS). This team had already succeeded in observing the electric field inside atoms for the first time in 2012. However, since the magnetic fields in atoms are extremely weak compared with electric fields, the technology to observe the magnetic fields had been unexplored since the development of electron microscopes. This is an epoch-making achievement that will rewrite the history of microscope development.

Electron microscopes have the highest spatial resolution among all currently used microscopes. However, in order to achieve ultra-high resolution so that atoms can be observed directly, we have to observe the sample by placing it in an extremely strong lens . Therefore, atomic observation of magnetic materials that are strongly affected by the lens magnetic field such as magnets and steels had been impossible for many years. For this , the team succeeded in developing a lens that has a completely new structure in 2019. Using this new lens, the team realized atomic observation of magnetic materials, which is not affected by the lens magnetic field. The team’s next goal was to observe the magnetic fields of atoms, which are the origin of magnets (), and they continued technological to achieve the goal.

This time, the joint development team took on the challenge of observing the magnetic fields of iron (Fe) atoms in a hematite crystal (α-Fe2O3) by loading MARS with a newly developed high-sensitivity high-speed detector, and further using computer image processing technology. To observe the magnetic fields, they used the Differential Phase Contrast (DPC) method at atomic resolution, which is an ultrahigh-resolution local electromagnetic field measurement method using a scanning transmission electron microscope (STEM), developed by Professor Shibata et al. The results directly demonstrated that iron atoms themselves are small magnets (atomic magnet). The results also clarified the origin of (antiferromagnetism) exhibited by hematite at the atomic level.

Feb 25, 2022

Physicists test real quantum theory in an optical quantum network

Posted by in category: quantum physics

Quantum theory was originally formulated using complex numbers. Nonetheless, when replying to a letter by Hendrik Lorenz, Erwin Schrödinger (one of its founding fathers), wrote: “Using complex numbers in quantum theory is unpleasant and should be objected to. The wave function is surely fundamentally a real function.”

In recent years, scientists successfully ruled out any local hidden variable explanation of quantum using Bell tests. Later, such tests were generalized to a network with multiple independent hidden variables. In such a quantum network, quantum theory with only real numbers, or “real quantum theory,” and standard quantum theory make quantitatively different predictions in some scenarios, enabling experimental tests of the validity of real quantum theory.

Researchers at Southern University of Science and Technology in China, the Austrian Academy of Sciences and other institutes worldwide have recently adapted one of these tests so that they could be implemented in state-of-the-art photonic systems. Their paper, published in Physical Review Letters, experimentally demonstrates the existence of quantum correlations in an optical network that cannot be explained by real quantum theory.

Feb 25, 2022

New model may improve Bay Area seismic hazard maps

Posted by in categories: chemistry, mapping

The Santa Cruz Mountains define the geography of the Bay Area south of San Francisco, protecting the peninsula from the Pacific Ocean’s cold marine layer and forming the region’s notorious microclimates. The range also represents the perils of living in Silicon Valley: earthquakes along the San Andreas fault.

In bursts that last seconds to minutes, earthquakes have moved the region’s surface meters at a time. But researchers have never been able to reconcile the quick release of the Earth’s stress and the bending of the Earth’s crust over years with the formation of mountain ranges over millions of years. Now, by combining geological, geophysical, geochemical and , geologists have created a 3D tectonic model that resolves these timescales.

The research, which appears in Science Advances Feb. 25, reveals that more mountain building happens in the period between along the San Andreas Fault, rather than during the quakes themselves. The findings may be used to improve local seismic hazard maps.

Feb 25, 2022

A new, inexpensive catalyst speeds the production of oxygen from water

Posted by in categories: chemistry, energy, transportation

An electrochemical reaction that splits apart water molecules to produce oxygen is at the heart of multiple approaches aiming to produce alternative fuels for transportation. But this reaction has to be facilitated by a catalyst material, and today’s versions require the use of rare and expensive elements such as iridium, limiting the potential of such fuel production.

Now, researchers at MIT and elsewhere have developed an entirely new type of catalyst material, called a metal hydroxide-organic framework (MHOF), which is made of inexpensive and abundant components. The family of materials allows engineers to precisely tune the ’s structure and composition to the needs of a particular chemical process, and it can then match or exceed the performance of conventional, more expensive catalysts.

The findings are described today in the journal Nature Materials, in a paper by MIT postdoc Shuai Yuan, graduate student Jiayu Peng, Professor Yang Shao-Horn, Professor Yuriy Román-Leshkov, and nine others.

Feb 25, 2022

New simulations refine axion mass, refocusing dark matter search

Posted by in categories: cosmology, physics, supercomputing

Physicists searching—unsuccessfully—for today’s most favored candidate for dark matter, the axion, have been looking in the wrong place, according to a new supercomputer simulation of how axions were produced shortly after the Big Bang 13.6 billion years ago.

Using new calculational techniques and one of the world’s largest computers, Benjamin Safdi, assistant professor of physics at the University of California, Berkeley; Malte Buschmann, a postdoctoral research associate at Princeton University; and colleagues at MIT and Lawrence Berkeley National Laboratory simulated the era when axions would have been produced, approximately a billionth of a billionth of a billionth of a second after the universe came into existence and after the epoch of cosmic inflation.

The at Berkeley Lab’s National Research Scientific Computing Center (NERSC) found the ’s to be more than twice as big as theorists and experimenters have thought: between 40 and 180 microelectron volts (micro-eV, or μeV), or about one 10-billionth the mass of the electron. There are indications, Safdi said, that the mass is close to 65 μeV. Since physicists began looking for the axion 40 years ago, estimates of the mass have ranged widely, from a few μeV to 500 μeV.

Feb 25, 2022

Stronger materials could bloom with new images of plastic flow

Posted by in categories: materials, space travel

Imagine dropping a tennis ball onto a bedroom mattress. The tennis ball will bend the mattress a bit, but not permanently—pick the ball back up, and the mattress returns to its original position and strength. Scientists call this an elastic state.

On the other hand, if you drop something heavy—like a refrigerator—the force pushes the mattress into what scientists call a plastic state. The plastic state, in this sense, is not the same as the plastic milk jug in your refrigerator, but rather a permanent rearrangement of the atomic structure of a material. When you remove the refrigerator, the mattress will be compressed and, well, uncomfortable, to say the least.

But a material’s elastic-plastic shift concerns more than mattress comfort. Understanding what happens to a material at the atomic level when it transitions from elastic to plastic under high pressures could allow scientists to design stronger materials for spacecraft and nuclear fusion experiments.

Feb 25, 2022

Scientists invent imaging method to assess quality of 3D-printed metal parts

Posted by in categories: mapping, materials

Scientists from Nanyang Technological University, Singapore (NTU Singapore), have developed a fast and low-cost imaging method that can analyze the structure of 3D-printed metal parts and offer insights into the quality of the material.

Most 3D-printed metal alloys consist of a myriad of microscopic crystals, which differ in shape, size, and atomic lattice orientation. By mapping out this information, scientists and engineers can infer the alloy’s properties, such as strength and toughness. This is similar to looking at wood grain, where wood is strongest when the grain is continuous in the same direction.

This new made-in-NTU technology could benefit, for example, the aerospace sector, where low-cost, rapid assessment of mission critical parts—turbine, fan blades and other components—could be a gamechanger for the maintenance, repair and overhaul industry.

Feb 25, 2022

World’s smallest battery can power computers with the size of a grain of dust

Posted by in category: futurism

A research team led by Chemnitz University of Technology with the participation of IFW Dresden and Changchun Institute of Applied Chemistry present an application-oriented method for an unsolved problem in microelectronics.

Feb 25, 2022

Synthesizing Triatomic Molecules Under Quantum Constraints

Posted by in categories: energy, quantum physics

Radio-Frequency Pulse Enables Association of Triatomic Molecules in Ultracold 23 Na40 K + 40 K Gas.

Three-body system is already formidable in classical physics, not to mention the quantum state three-body system. But what if scientists can synthesize triatomic molecules under quantum constraints? It could serve as an appropriate platform to study three-body potential energy surface which is important but difficult to calculate.

Recently, Prof. PAN Jianwei and Prof. ZHAO Bo from the University of Science and Technology of China (USTC), collaborating with Prof. BAI Chunli from Institute of Chemistry of the Chinese Academy of Sciences, found strong evidence for association of triatomic molecules after applying a radio-frequency (rf) pulse to an ultracold mixture of 23 Na40 K and 40 K near Feshbach resonance. The work was published in the journal Nature.

Feb 25, 2022

MIT Chemists Discover Structure of Protein That Pumps Toxic Molecules Out of Bacterial Cells

Posted by in category: biotech/medical

MIT chemists have discovered how the structure of the EmrE transporter changes as a compound moves through it. At left is the transporter structure at high pH. As the pH drops (right), the helices begin to tilt so that the channel is more open toward the outside of the cell, guiding the compound out. Credit: Courtesy of the researchers.

A new study sheds light on how a protein pumps toxic molecules out of bacterial cells.

MIT chemists have discovered the structure of a protein that can pump toxic molecules out of bacterial cells. Proteins similar to this one, which is found in E. coli, are believed to help bacteria become resistant to multiple antibiotics.