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  • richardmitnick 7:13 am on July 19, 2019 Permalink | Reply
    Tags: Nanotechnology, , , Magnetometry, "New Laws of Attraction: Scientists Print Magnetic Liquid Droplets", A revolutionary class of printable liquid devices for a variety of applications, Ferrofluids- solutions of iron-oxide particles that become strongly magnetic in the presence of another magnet.   

    From Lawrence Berkeley National Lab- “New Laws of Attraction: Scientists Print Magnetic Liquid Droplets” 

    Berkeley Logo

    From Lawrence Berkeley National Lab

    July 18, 2019
    Theresa Duque
    tnduque@lbl.gov
    510-495-2418

    Revolutionary material could lead to 3D-printable magnetic liquid devices for the fabrication of flexible electronics, or artificial cells that deliver targeted drug therapies to diseased cells.


    Scientists at Berkeley Lab have made a new material that is both liquid and magnetic, opening the door to a new area of science in magnetic soft matter. Their findings could lead to a revolutionary class of printable liquid devices for a variety of applications from artificial cells that deliver targeted cancer therapies to flexible liquid robots that can change their shape to adapt to their surroundings. (Video credit: Marilyn Chung/Berkeley Lab; footage of droplets courtesy of Xubo Liu and Tom Russell/Berkeley Lab)

    Inventors of centuries past and scientists of today have found ingenious ways to make our lives better with magnets – from the magnetic needle on a compass to magnetic data storage devices and even MRI body scan machines.

    All of these technologies rely on magnets made from solid materials. But what if you could make a magnetic device out of liquids? Using a modified 3D printer, a team of scientists at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have done just that. Their findings, to be published July 19 in the journal Science, could lead to a revolutionary class of printable liquid devices for a variety of applications – from artificial cells that deliver targeted cancer therapies to flexible liquid robots that can change their shape to adapt to their surroundings.

    “We’ve made a new material that is both liquid and magnetic. No one has ever observed this before,” said Tom Russell, a visiting faculty scientist at Berkeley Lab and professor of polymer science and engineering at the University of Massachusetts, Amherst, who led the study. “This opens the door to a new area of science in magnetic soft matter.”

    For the past seven years, Russell, who leads a program called Adaptive Interfacial Assemblies Towards Structuring Liquids in Berkeley Lab’s Materials Sciences Division and also led the current study, has focused on developing a new class of materials – 3D-printable all-liquid structures.

    1
    Array of 1 millimeter magnetic droplets: Fluorescent green droplets are paramagnetic without any jammed nanoparticles at the liquid interface; red are paramagnetic with nonmagnetic nanoparticles jammed at the interface; brown droplets are ferromagnetic with magnetic nanoparticles jammed at the interface. (Credit: Xubo Liu et al./Berkeley Lab)

    Russell and Xubo Liu, the study’s lead author, came up with the idea of forming liquid structures from ferrofluids, which are solutions of iron-oxide particles that become strongly magnetic in the presence of another magnet. “We wondered, ‘If a ferrofluid can become temporarily magnetic, what could we do to make it permanently magnetic, and behave like a solid magnet but still look and feel like a liquid?’” said Russell.

    Jam sessions: making magnets out of liquids

    To find out, Russell and Liu used a 3D-printing technique they had developed with former postdoctoral researcher Joe Forth in Berkeley Lab’s Materials Sciences Division to print 1 millimeter droplets from a ferrofluid solution containing iron-oxide nanoparticles just 20 nanometers in diameter (the average size of an antibody protein).

    Using surface chemistry and sophisticated atomic force microscopy techniques, staff scientists Paul Ashby and Brett Helms of Berkeley Lab’s Molecular Foundry revealed that the nanoparticles formed a solid-like shell at the interface between the two liquids through a phenomenon called “interfacial jamming.” This causes the nanoparticles to crowd at the droplet’s surface, “like the walls coming together in a small room jampacked with people,” said Russell.

    To make them magnetic, the scientists placed the droplets by a magnetic coil in solution. As expected, the magnetic coil pulled the iron-oxide nanoparticles toward it.

    But when they removed the magnetic coil, something quite unexpected happened.

    3
    Permanently magnetized iron-oxide nanoparticles gravitate toward each other in perfect unison. (Credit: Xubo Liu et al./Berkeley Lab)

    Like synchronized swimmers, the droplets gravitated toward each other in perfect unison, forming an elegant swirl “like little dancing droplets,” said Liu, who is a graduate student researcher in Berkeley Lab’s Materials Sciences Division and a doctoral student at the Beijing University of Chemical Technology.

    Somehow, these droplets had become permanently magnetic. “We almost couldn’t believe it,” said Russell. “Before our study, people always assumed that permanent magnets could only be made from solids.”

    Measure by measure, it’s still a magnet

    All magnets, no matter how big or small, have a north pole and a south pole. Opposite poles are attracted to each other, while the same poles repel each other.

    Through magnetometry measurements, the scientists found that when they placed a magnetic field by a droplet, all of the nanoparticles’ north-south poles, from the 70 billion iron-oxide nanoparticles floating around in the droplet to the 1 billion nanoparticles on the droplet’s surface, responded in unison, just like a solid magnet.

    Key to this finding were the iron-oxide nanoparticles jamming tightly together at the droplet’s surface. With just 8 nanometers between each of the billion nanoparticles, together they created a solid surface around each liquid droplet.

    Somehow, when the jammed nanoparticles on the surface are magnetized, they transfer this magnetic orientation to the particles swimming around in the core, and the entire droplet becomes permanently magnetic – just like a solid, Russell and Liu explained.

    The researchers also found that the droplet’s magnetic properties were preserved even if they divided a droplet into smaller, thinner droplets about the size of a human hair, added Russell.

    3
    To make the iron-oxide nanoparticles permanently magnetic, the scientists placed the droplets by a magnetic coil in solution. As expected, the magnetic coil pulled the iron-oxide nanoparticles toward it. (Credit: Xubo Liu et al./Berkeley Lab

    Among the magnetic droplets’ many amazing qualities, what stands out even more, Russell noted, is that they change shape to adapt to their surroundings. They morph from a sphere to a cylinder to a pancake, or a tube as thin as a strand of hair, or even to the shape of an octopus – all without losing their magnetic properties.

    The droplets can also be tuned to switch between a magnetic mode and a nonmagnetic mode. And when their magnetic mode is switched on, their movements can be remotely controlled as directed by an external magnet, Russell added.

    Liu and Russell plan to continue research at Berkeley Lab and other national labs to develop even more complex 3D-printed magnetic liquid structures, such as a liquid-printed artificial cell, or miniature robotics that move like a tiny propeller for noninvasive yet targeted delivery of drug therapies to diseased cells.

    “What began as a curious observation ended up opening a new area of science,” said Liu. “It’s something all young researchers dream of, and I was lucky to have the chance to work with a great group of scientists supported by Berkeley Lab’s world-class user facilities to make it a reality,” said Liu.

    Also contributing to the study were researchers from UC Santa Cruz, UC Berkeley, the WPI–Advanced Institute for Materials Research (WPI-AIMR) at Tohoku University, and Beijing University of Chemical Technology.

    The magnetometry measurements were taken with assistance from Berkeley Lab Materials Sciences Division co-authors Peter Fischer, senior staff scientist; Frances Hellman, senior faculty scientist and professor of physics at UC Berkeley; Robert Streubel, postdoctoral fellow; Noah Kent, graduate student researcher and doctoral student at UC Santa Cruz; and Alejandro Ceballos, Berkeley Lab graduate student researcher and doctoral student at UC Berkeley.

    Other co-authors are staff scientists Paul Ashby and Brett Helms, and postdoctoral researchers Yu Chai and Paul Kim, with Berkeley Lab’s Molecular Foundry; Yufeng Jiang, graduate student researcher in Berkeley Lab’s Materials Sciences Division; and Shaowei Shi and Dong Wang of Beijing University of Chemical Technology.

    This work was supported by the DOE Office of Science and included research at the Molecular Foundry, a DOE Office of Science User Facility that specializes in nanoscale science.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    LBNL campus

    Bringing Science Solutions to the World
    In the world of science, Lawrence Berkeley National Laboratory (Berkeley Lab) is synonymous with “excellence.” Thirteen Nobel prizes are associated with Berkeley Lab. Seventy Lab scientists are members of the National Academy of Sciences (NAS), one of the highest honors for a scientist in the United States. Thirteen of our scientists have won the National Medal of Science, our nation’s highest award for lifetime achievement in fields of scientific research. Eighteen of our engineers have been elected to the National Academy of Engineering, and three of our scientists have been elected into the Institute of Medicine. In addition, Berkeley Lab has trained thousands of university science and engineering students who are advancing technological innovations across the nation and around the world.

    Berkeley Lab is a member of the national laboratory system supported by the U.S. Department of Energy through its Office of Science. It is managed by the University of California (UC) and is charged with conducting unclassified research across a wide range of scientific disciplines. Located on a 202-acre site in the hills above the UC Berkeley campus that offers spectacular views of the San Francisco Bay, Berkeley Lab employs approximately 3,232 scientists, engineers and support staff. The Lab’s total costs for FY 2014 were $785 million. A recent study estimates the Laboratory’s overall economic impact through direct, indirect and induced spending on the nine counties that make up the San Francisco Bay Area to be nearly $700 million annually. The Lab was also responsible for creating 5,600 jobs locally and 12,000 nationally. The overall economic impact on the national economy is estimated at $1.6 billion a year. Technologies developed at Berkeley Lab have generated billions of dollars in revenues, and thousands of jobs. Savings as a result of Berkeley Lab developments in lighting and windows, and other energy-efficient technologies, have also been in the billions of dollars.

    Berkeley Lab was founded in 1931 by Ernest Orlando Lawrence, a UC Berkeley physicist who won the 1939 Nobel Prize in physics for his invention of the cyclotron, a circular particle accelerator that opened the door to high-energy physics. It was Lawrence’s belief that scientific research is best done through teams of individuals with different fields of expertise, working together. His teamwork concept is a Berkeley Lab legacy that continues today.

    A U.S. Department of Energy National Laboratory Operated by the University of California.

    University of California Seal

    DOE Seal

     
  • richardmitnick 8:53 am on July 18, 2019 Permalink | Reply
    Tags: "200 times faster than ever before: the speediest quantum operation yet", Nanotechnology, , Scanning tunnelling microscopy, The first two-qubit gate between atom qubits in silicon,   

    From University of New South Wales: “200 times faster than ever before: the speediest quantum operation yet” 

    U NSW bloc

    From University of New South Wales

    18 Jul 2019
    Isabelle Dubach

    A group of physicists at UNSW Sydney have built a super-fast version of the central building block of a quantum computer. The research is the milestone result of a vision first outlined by scientists 20 years ago.

    1
    From left to right: Professor Michelle Simmons, Dr. Sam Gorman, Postdoc Research Associate, Dr. Yu He, Postdoc Research Associate, Ludwik Kranz, PhD student, Dr. Joris Keizer, Senior Research Fellow, Daniel Keith, PhD student

    A group of scientists led by 2018 Australian of the Year Professor Michelle Simmons have achieved the first two-qubit gate between atom qubits in silicon – a major milestone on the team’s quest to build an atom-scale quantum computer. The pivotal piece of research was published today in world-renowned journal Nature.

    A two-qubit gate is the central building block of any quantum computer – and the UNSW team’s version of it is the fastest that’s ever been demonstrated in silicon, completing an operation in 0.8 nanoseconds, which is ~200 times faster than other existing spin-based two-qubit gates.

    In the Simmons’ group approach, a two-qubit gate is an operation between two electron spins – comparable to the role that classical logic gates play in conventional electronics. For the first time, the team was able to build a two-qubit gate by placing two atom qubits closer together than ever before, and then – in real-time – controllably observing and measuring their spin states.

    The team’s unique approach to quantum computing requires not only the placement of individual atom qubits in silicon but all the associated circuitry to initialise, control and read-out the qubits at the nanoscale – a concept that requires such exquisite precision it was long thought to be impossible. But with this major milestone, the team is now positioned to translate their technology into scalable processors.

    Professor Simmons, Director of the Centre of Excellence for Quantum Computation and Communication Technology (CQC2T) and founder of Silicon Quantum Computing Pty Ltd., says the past decade of previous results perfectly set the team up to shift the boundaries of what’s thought to be “humanly possible”.

    “Atom qubits hold the world record for the longest coherence times of a qubit in silicon with the highest fidelities,” she says. “Using our unique fabrication technologies, we have already demonstrated the ability to read and initialise single electron spins on atom qubits in silicon with very high accuracy. We’ve also demonstrated that our atomic-scale circuitry has the lowest electrical noise of any system yet devised to connect to a semiconductor qubit.

    “Optimising every aspect of the device design with atomic precision has now allowed us to build a really fast, highly accurate two-qubit gate, which is the fundamental building block of a scalable, silicon-based quantum computer.

    “We’ve really shown that it is possible to control the world at the atomic scale – and that the benefits of the approach are transformational, including the remarkable speed at which our system operates.”

    UNSW Science Dean, Professor Emma Johnston AO, says this key paper further shows just how ground-breaking Professor Simmons’ research is.

    “This was one of Michelle’s team’s final milestones to demonstrate that they can actually make a quantum computer using atom qubits. Their next major goal is building a 10-qubit quantum integrated circuit – and we hope they reach that within 3-4 years.”

    Getting up and close with qubits – engineering with a precision of just thousand-millionths of a metre

    Using a scanning tunnelling microscope to precision-place and encapsulate phosphorus atoms in silicon, the team first had to work out the optimal distance between two qubits to enable the crucial operation.

    “Our fabrication technique allows us to place the qubits exactly where we want them. This allows us to engineer our two-qubit gate to be as fast as possible,” says study lead co-author Sam Gorman from CQC2T.

    “Not only have we brought the qubits closer together since our last breakthrough, but we have learnt to control every aspect of the device design with sub-nanometer precision to maintain the high fidelities.”

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    U NSW Campus

    Welcome to UNSW Australia (The University of New South Wales), one of Australia’s leading research and teaching universities. At UNSW, we take pride in the broad range and high quality of our teaching programs. Our teaching gains strength and currency from our research activities, strong industry links and our international nature; UNSW has a strong regional and global engagement.

    In developing new ideas and promoting lasting knowledge we are creating an academic environment where outstanding students and scholars from around the world can be inspired to excel in their programs of study and research. Partnerships with both local and global communities allow UNSW to share knowledge, debate and research outcomes. UNSW’s public events include concert performances, open days and public forums on issues such as the environment, healthcare and global politics. We encourage you to explore the UNSW website so you can find out more about what we do.

     
  • richardmitnick 12:16 pm on July 17, 2019 Permalink | Reply
    Tags: , , Glass technology, , Nanotechnology,   

    From UCLA Newsroom: “UCLA researchers toughen glass using nanoparticles” 


    From UCLA Newsroom

    July 16, 2019
    Matthew Chin

    Process could be useful for applications in manufacturing and architecture.

    1
    An electron microscope image of a new, tougher glass developed at UCLA, showing how nanoparticles (rounded, irregular shapes) deflect a crack and force it to branch out. SciFacturing Lab/UCLA

    UCLA mechanical engineers and materials scientists have developed a process that uses nanoparticles to strengthen the atomic structure of glass. The result is a product that’s at least five times tougher than any glass currently available.

    The process could yield glass that’s useful for industrial applications — in engine components and tools that can withstand high temperatures, for instance — as well as for doors, tables and other architectural and design elements.

    The study was published online in the journal Advanced Materials and will be included in a future print edition. The authors wrote that same approach could also be used for manufacturing tougher ceramics that could be used, for example, in spacecraft components that are better able to withstand extreme heat.

    In materials science, “toughness” measures how much energy a material can absorb — and how much it can deform — without fracturing. While glass and ceramics can be reinforced using external treatments, like chemical coatings, those approaches don’t change the fact that the materials themselves are brittle.

    To solve that issue, the UCLA researchers took a cue from the atomic structure of metals, which can take a pounding and not break.

    “The chemical bonds that hold glass and ceramics together are pretty rigid, while the bonds in metals allow some flexibility,” said Xiaochun Li, the Raytheon Professor of Manufacturing at the UCLA Samueli School of Engineering, and the study’s principal investigator. “In glass and ceramics, when the impact is strong enough, a fracture will propagate quickly through the material in a mostly straight path.

    “When something impacts a metal, its more deformable chemical bonds act as shock absorbers and its atoms move around while still holding the structure together.”

    The researchers hypothesized that by infusing glass with nanoparticles of silicon carbide, a metal-like ceramic, the resulting material would be able to absorb more energy before it would fail. They added the nanoparticles into molten glass at 3,000 degrees Fahrenheit, which helped ensure that the nanoparticles were evenly dispersed.

    Once the material solidified, the embedded nanoparticles could act as roadblocks to potential fractures. When a fracture does occur, the tiny particles force it to branch out into tiny networks, instead of allowing it to take a straight path. That branching out enables the glass to absorb significantly more energy from a fracture before it causes significant damage.

    Sintering, in which a powder is heated under pressure, and then cooled, is the main method used to make glass. It also was the method used in previous experiments by other research groups to disperse nanoparticles in glass or ceramics. But in those experiments, the nanoparticles weren’t spread evenly, and the resulting material had uneven toughness.

    The glass blocks that the UCLA team developed for the experiment were somewhat milky, rather than clear, but Li said the process could be adapted to create clear glass.

    The other authors of the study are Qiang-Guo Jiang, a visiting scholar in Li’s SciFacturing Laboratory; Chezheng Cao and Ting-Chiang Lin, who received their doctorates from UCLA in 2018; and Shanghua Wu, an engineering professor at Guangdong University of Technology, China.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    UC LA Campus

    For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

    We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

    This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

     
  • richardmitnick 10:24 am on July 17, 2019 Permalink | Reply
    Tags: , , DSSC detector, , MiniSDD sensors, Nanotechnology, SCS-Spectroscopy and Coherent Scattering,   

    From European XFEL: “Fastest soft X-ray camera in the world installed at European XFEL” 

    XFEL bloc

    European XFEL

    From European XFEL

    DSSC detector will expand scientific capabilities of the instrument for Spectroscopy and Coherent Scattering (SCS)

    1
    DSSC detector

    At European XFEL near Hamburg the world’s fastest soft X-ray camera has successfully been put through its paces. The installation, commissioning and operation of the unique detector marks the culmination of over a decade of international collaborative research and development. The so-called DSSC detector, designed specifically for the low energy regimes and long X-ray wavelengths used at the European XFEL soft X-ray instruments, will significantly expand the scientific capabilities of the instrument for Spectroscopy and Coherent Scattering (SCS) where it is installed. It will enable ultrafast studies of electronic, spin and atomic structures at the nanoscale making use of each X-ray flash provided by European XFEL. At the end of May, the first scientific experiments using the DSSC were successfully conducted at SCS.

    The DSSC was developed by an international consortium coordinated by European XFEL. Other partners include DESY, University of Heidelberg, Politecnico di Milano, the Istituto Nazionale di Fisica Nucleare, and University of Bergamo. It is the fourth fast X-ray detector to be installed at European XFEL, and the second detector available for experiments at the SCS instrument.

    Matteo Porro, DSSC project and consortium leader said: “This is a fantastic achievement in terms of detector development and it opens up unique possibilities for the photon science community. With the DSSC we have shown that it is possible to count single photons in the soft X-ray regime at the very high pulse repetition rate provided by the European XFEL. I would like to thank the DSSC consortium, who with their commitment and creativity, have made this possible. It was a privilege to work with people who provided such an extraordinary level of know-how in detector and electronics design.”

    During an experiment, X-ray flashes are fired at the sample being studied. The X-rays diffract off the atoms in the sample, resulting in a distinctive pattern that is recorded and stored by the detector located behind the sample. The European XFEL delivers X-rays flashes grouped together in packets known as trains. Each train contains a maximum of 2700 flashes. Within these trains the X-ray flashes are fired in quick succession with a time difference of 220 nanoseconds. At full capacity, the DSSC detector can acquire images at a rate of 4.5 million images per second, matching the speed of the X-ray flashes provided by the European XFEL. For every train the DSSC detector can store 800 one megapixel images. This makes the DSSC the fastest soft X-ray detector in the world. It was designed and built to accommodate the low energy regimes and long wavelengths unique to the soft X-ray instruments at European XFEL. The DSSC detector is based on silicon sensors and is made up of 1024 x 1024 hexagonal pixels for a total active area of 210 x 210 mm2.

    The DSSC detector is currently equipped with a type of sensors called MiniSDD sensors which were produced by the Semiconductor Laboratory of the Max Planck Society in Munich. PNSensor GmbH based in Munich, recently joined the DSSC consortium to further develop another type of sensor, DePFET, for a second improved DSSC camera. This will enable an even greater level of detail to be recorded than currently possible.

    “After years of design and development, it was great to see the individual detector components being assembled together at European XFEL during this past year. This was as an extremely exciting and intense time.” European XFEL Detector Group leader Markus Kuster says. “Having seen the results of the first scientific experiment with the DSSC, I am proud of the whole project team and pleased that our efforts are now bearing fruits. This is a fantastic start for the future development of the DSSC detector technology.”

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    XFEL Campus

    XFEL Tunnel

    XFEL Gun

    The Hamburg area will soon boast a research facility of superlatives: The European XFEL will generate ultrashort X-ray flashes—27 000 times per second and with a brilliance that is a billion times higher than that of the best conventional X-ray radiation sources.

    The outstanding characteristics of the facility are unique worldwide. Started in 2017, it will open up completely new research opportunities for scientists and industrial users.

     
  • richardmitnick 7:52 am on July 15, 2019 Permalink | Reply
    Tags: Nanotechnology, , , , MTU-Michigan Technical University   

    From Michigan Technical University: “AI Searches for New Nanomaterials” 

    Michigan Tech bloc

    From Michigan Technical University

    By Jenny Woodman
    Computing And Data Science
    Science And Engineering

    The researchers-

    Yoke Khin Yap
    ykyap@mtu.edu
    906-487-2900

    Susanta Ghosh
    susantag@mtu.edu
    906-487-2689

    1
    Michigan Technological University

    There’s a method to my development of new nanomaterials.

    Marilyn Monroe may have convinced previous generations that diamonds are a girl’s best friend, but in the future people may not sing the praises of sparkly carbon-based gemstones; they might be singing about new nanomaterials related to graphene and nanotubes. Thanks to a multidisciplinary collaboration using artificial intelligence (AI), physicist Yoke Khin Yap at Michigan Technological University and a team of researchers hope to develop new nanomaterials that are smaller and much stronger than diamonds.

    About Those Nanotubes…

    Nanotubes and graphene are a class of low-dimensional materials that can be composed of carbon or some combination of carbon, boron or nitrogen (B-C-N nanomaterials). The molecular bonds that join the atoms to form these nanomaterials are remarkably strong and they have wide-ranging applications, from water purification to biomedical research, from solar cells to semiconductors for computing and electronics.

    DFT, AI, and Other Helpful Acronyms

    The work happens at a nanoscale — and Yap’s team needs an atomic window. Thanks to an instrumentation grant from the National Science Foundation (NSF), Michigan Tech purchased a scanning transmission electron microscope (STEM) in 2018. According to Yap, the system “allows us to image nanomaterials at the atomic resolution, and at the same time we can touch them; we can probe them; we can characterize them in situ.”

    2
    360-Degree View of the STEM. Michigan Technological University

    But getting a material to the microscope is a long road. What if new materials could be invented before they’re seen?

    Yap’s work was inspired by Density Functional Theory (DFT) developed in the 1970s. DFT is widely used in both academia and industry to study materials and predict behaviors at an atomic level, including the structure and electronic properties. In the early days of the theory, there were limitations; DFT was not terribly accurate. According to Yap, DFT told experimentalists important information about the properties of a new structure, but offered little insight about how to make those theoretical materials a reality. He adds that DFT predictions are better suited to the nanoscale, involving 100 atoms or fewer. Therefore, predicting new nanomaterials is the sweet spot of DFT.

    But AI makes the process even more interesting and sophisticated.

    Computer scientists plug in data from current published research on new materials and then compare that information using a popular type of vector-space modeling called Word Embedding. The researchers are looking for places where keywords, such as carbon nanotubes and graphene, might overlap with properties such as band gap or mobility, said Yap.

    “They use a computer to dig into all the theoretical predictions that are being published by physicists and chemists,” Yap said. “This brings together all the kinds of theory out there and we find there is a subset that potentially more people agree upon.”

    From there, the researchers take those data-mined results and feed them into a convolutional neural network (CNN), which is a type of machine deep-learning network wherein the computer applies logic to make predictions. By applying layer upon layer of filters, the CNN reveals even more patterns in the data.

    Susanta Ghosh is an assistant professor of mechanical engineering at Michigan Tech and works on new materials with Yap. He said, “The biggest challenge in the Materials by Design paradigm is the high-dimensionality of the material design space due to the vast amount of possible combinations or conditions that lead to different materials.”

    In other words, the design process is complicated by a staggeringly high number of dimensions.

    “Data-driven modeling integrated with experiments or simulations is showing tremendous promise to overcome this challenge,” Ghosh added. “Data-driven modeling, such as machine learning, is opening new possibilities for creating structure-property relations across diverse material length and time scales and enabling optimization in the microstructural space for material design.”

    The process is lengthy — and like DFT it’s limited to identifying what materials are possible. Yap said further research with another layer of DFT modeling on the dynamic of chemical reaction may reinforce the prediction from CNN and offer insights about how to actually fabricate the materials. He anticipates seeing new materials in the next 10 to 15 years.

    “It is complicated and it will become a very interdisciplinary collaboration between theorists, computer scientists, experimental physicists and chemists to make the new nanomaterials,” Yap said.

    This multidisciplinary approach advances existing knowledge and theory about the next generation of materials for computing, medicine, engineering and more. With AI and atomic imaging, possibilities won’t lose their shape and nanomaterials — not diamonds — are a physicist’s best friend.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Michigan Tech Campus
    Michigan Technological University (http://www.mtu.edu) is a leading public research university developing new technologies and preparing students to create the future for a prosperous and sustainable world. Michigan Tech offers more than 130 undergraduate and graduate degree programs in engineering; forest resources; computing; technology; business; economics; natural, physical and environmental sciences; arts; humanities; and social sciences.
    The College of Sciences and Arts (CSA) fills one of the most important roles on the Michigan Tech campus. We play a part in the education of every student who comes through our doors. We take pride in offering essential foundational courses in the natural sciences and mathematics, as well as the social sciences and humanities—courses that underpin every major on campus. With twelve departments, 28 majors, 30-or-so specializations, and more than 50 minors, CSA has carefully developed programs to suit many interests and skill sets. From sound design and audio technology to actuarial science, applied cognitive science and human factors to rhetoric and technical communication, the college offers many unique programs.

     
  • richardmitnick 11:56 am on July 12, 2019 Permalink | Reply
    Tags: "Enriching solid-state batteries", , , Jennifer Rupp, , , , Nanotechnology, ,   

    From MIT News: Women in STEM-“Enriching solid-state batteries” Jennifer Rupp 

    MIT News

    From MIT News

    July 11, 2019
    Denis Paiste | Materials Research Laboratory

    1
    MIT Associate Professor Jennifer Rupp stands in front of a pulsed laser deposition chamber, in which her team developed a new lithium garnet electrolyte material with the fastest reported ionic conductivity of its type. The technique produces a thin film about 330 nanometers thick. “Having the lithium electrolyte as a solid-state very fast conductor allows you to dream out loud of anything else you can do with fast lithium motion,” Rupp says. Photo: Denis Paiste/Materials Research Laboratory

    Researchers at MIT have come up with a new pulsed laser deposition technique to make thinner lithium electrolytes using less heat, promising faster charging and potentially higher-voltage solid-state lithium ion batteries.

    Key to the new technique for processing the solid-state battery electrolyte is alternating layers of the active electrolyte lithium garnet component (chemical formula, Li6.25Al0.25La3Zr2O12, or LLZO) with layers of lithium nitride (chemical formula Li3N). First, these layers are built up like a wafer cookie using a pulsed laser deposition process at about 300 degrees Celsius (572 degrees Fahrenheit). Then they are heated to 660 C and slowly cooled, a process known as annealing.

    During the annealing process, nearly all of the nitrogen atoms burn off into the atmosphere and the lithium atoms from the original nitride layers fuse into the lithium garnet, forming a single lithium-rich, ceramic thin film. The extra lithium content in the garnet film allows the material to retain the cubic structure needed for positively charged lithium ions (cations) to move quickly through the electrolyte. The findings were reported in a Nature Energy paper published online recently by MIT Associate Professor Jennifer L. M. Rupp and her students Reto Pfenninger, Michal M. Struzik, Inigo Garbayo, and collaborator Evelyn Stilp.

    “The really cool new thing is that we found a way to bring the lithium into the film at deposition by using lithium nitride as an internal lithiation source,” Rupp, the work’s senior author, says. Rupp holds joint MIT appointments in the departments of Materials Science and Engineering and Electrical Engineering and Computer Science.

    “The second trick to the story is that we use lithium nitride, which is close in bandgap to the laser that we use in the deposition, whereby we have a very fast transfer of the material, which is another key factor to not lose lithium to evaporation during a pulsed laser deposition,” Rupp explains.

    Safer technology

    Lithium batteries with commonly used electrolytes made by combining a liquid and a polymer can pose a fire risk when the liquid is exposed to air. Solid-state batteries are desirable because they replace the commonly used liquid polymer electrolytes in consumer lithium batteries with a solid material that is safer. “So we can kick that out, bring something safer in the battery, and decrease the electrolyte component in size by a factor of 100 by going from the polymer to the ceramic system,” Rupp explains.

    Although other methods to produce lithium-rich ceramic materials on larger pellets or tapes, heated using a process called sintering, can yield a dense microstructure that retains a high lithium concentration, they require higher heat and result in bulkier material. The new technique pioneered by Rupp and her students produces a thin film that is about 330 nanometers thick (less than 1.5 hundred-thousandths of an inch). “Having a thin film structure instead of a thick ceramic is attractive for battery electrolyte in general because it allows you to have more volume in the electrodes, where you want to have the active storage capacity. So the holy grail is be thin and be fast,” she says.

    Compared to the classic ceramic coffee mug, which under high magnification shows metal oxide particles with a grain size of tens to hundreds of microns, the lithium (garnet) oxide thin films processed using Rupp’s methods show nanometer scale grain structures that are one-thousandth to one-ten-thousandth the size. That means Rupp can engineer thinner electrolytes for batteries. “There is no need in a solid-state battery to have a large electrolyte,” she says.

    Faster ionic conduction

    Instead, what is needed is an electrolyte with faster conductivity. The unit of measurement for lithium ion conductivity is expressed in Siemens. The new multilayer deposition technique produces a lithium garnet (LLZO) material that shows the fastest ionic conductivity yet for a lithium-based electrolyte compound, about 2.9 x 10-5 Siemens (0.000029 Siemens) per centimeter. This ionic conductivity is competitive with solid-state lithium battery thin film electrolytes based on LIPON (lithium phosphorus oxynitride electrolytes) and adds a new film electrolyte material to the landscape.

    “Having the lithium electrolyte as a solid-state very fast conductor allows you to dream out loud of anything else you can do with fast lithium motion,” Rupp says.

    A battery’s negatively charged electrode stores power. The work points the way toward higher-voltage batteries based on lithium garnet electrolytes, both because its lower processing temperature opens the door to using materials for higher voltage cathodes that would be unstable at higher processing temperatures, and its smaller electrolyte size allows physically larger cathode volume in the same battery size.

    Co-authors Michal Struzik and Reto Pfenninger carried out processing and Raman spectroscopy measurements on the lithium garnet material. These measurements were key to showing the material’s fast conduction at room temperature, as well as understanding the evolution of its different structural phases.

    “One of the main challenges in understanding the development of the crystal structure in LLZO was to develop appropriate methodology. We have proposed a series of experiments to observe development of the crystal structure in the [LLZO] thin film from disordered or ‘amorphous’ phase to fully crystalline, highly conductive phase utilizing Raman spectroscopy upon thermal annealing under controlled atmospheric conditions,” says co-author Struzik, who was a postdoc working at ETH Zurich and MIT with Rupp’s group, and is now a professor at Warsaw University of Technology in Poland. “That allowed us to observe and understand how the crystal phases are developed and, as a consequence, the ionic conductivity improved,” he explains.

    Their work shows that during the annealing process, lithium garnet evolves from the amorphous phase in the initial multilayer processed at 300 C through progressively higher temperatures to a low conducting tetragonal phase in a temperature range from about 585 C to 630 C, and to the desired highly conducting cubic phase after annealing at 660 C. Notably, this temperature of 660 C to achieve the highly conducting phase in the multilayer approach is nearly 400 C lower than the 1,050 C needed to achieve it with prior sintering methods using pellets or tapes.

    “One of the greatest challenges facing the realization of solid-state batteries lies in the ability to fabricate such devices. It is tough to bring the manufacturing costs down to meet commercial targets that are competitive with today’s liquid-electrolyte-based lithium-ion batteries, and one of the main reasons is the need to use high temperatures to process the ceramic solid electrolytes,” says Professor Peter Bruce, the Wolfson Chair of the Department of Materials at Oxford University, who was not involved in this research.

    “This important paper reports a novel and imaginative approach to addressing this problem by reducing the processing temperature of garnet-based solid-state batteries by more than half — that is, by hundreds of degrees,” Bruce adds. “Normally, high temperatures are required to achieve sufficient solid-state diffusion to intermix the constituent atoms of ceramic electrolyte. By interleaving lithium layers in an elegant nanostructure the authors have overcome this barrier.”

    After demonstrating the novel processing and high conductivity of the lithium garnet electrode, the next step will be to test the material in an actual battery to explore how the material reacts with a battery cathode and how stable it is. “There is still a lot to come,” Rupp predicts.

    Understanding aluminum dopant sites

    A small fraction of aluminum is added to the lithium garnet formulation because aluminum is known to stabilize the highly conductive cubic phase in this high-temperature ceramic. The researchers complemented their Raman spectroscopy analysis with another technique, known as negative-ion time-of-flight secondary ion mass spectrometry (TOF-SIMS), which shows that the aluminum retains its position at what were originally the interfaces between the lithium nitride and lithium garnet layers before the heating step expelled the nitrogen and fused the material.

    “When you look at large-scale processing of pellets by sintering, then everywhere where you have a grain boundary, you will find close to it a higher concentration of aluminum. So we see a replica of that in our new processing, but on a smaller scale at the original interfaces,” Rupp says. “These little things are what adds up, also, not only to my excitement in engineering but my excitement as a scientist to understand phase formations, where that goes and what that does,” Rupp says.

    “Negative TOF-SIMS was indeed challenging to measure since it is more common in the field to perform this experiment with focus on positively charged ions,” explains Pfenninger, who worked at ETH Zurich and MIT with Rupp’s group. “However, for the case of the negatively charged nitrogen atoms we could only track it in this peculiar setup. The phase transformations in thin films of LLZO have so far not been investigated in temperature-dependent Raman spectroscopy — another insight towards the understanding thereof.”

    The paper’s other authors are Inigo Garbayo, who is now at CIC EnergiGUNE in Minano, Spain, and Evelyn Stilp, who was then with Empa, Swiss Federal Laboratories for Materials Science and Technology, in Dubendorf, Switzerland.

    Rupp began this research while serving as a professor of electrochemical materials at ETH Zurich (the Swiss Federal Institute of Technology) before she joined the MIT faculty in February 2017. MIT and ETH have jointly filed for two patents on the multi-layer lithium garnet/lithium nitride processing. This new processing method, which allows precise control of lithium concentration in the material, can also be applied to other lithium oxide films such as lithium titanate and lithium cobaltate that are used in battery electrodes. “That is something we invented. That’s new in ceramic processing,” Rupp says.

    “It is a smart idea to use Li3N as a lithium source during preparation of the garnet layers, as lithium loss is a critical issue during thin film preparation otherwise,” comments University Professor Jürgen Janek at Justus Liebig University Giessen in Germany. Janek, who was not involved in this research, adds that “the quality of the data and the analysis is convincing.”

    “This work is an exciting first step in preparing one of the best oxide-based solid electrolytes in an intermediate temperature range,” Janek says. “It will be interesting to see whether the intermediate temperature of about 600 degrees C is sufficient to avoid side reactions with the electrode materials.”

    Oxford Professor Bruce notes the novelty of the approach, adding “I’m not aware of similar nanostructured approaches to reduce diffusion lengths in solid-state synthesis.”

    “Although the paper describes specific application of the approach to the formation of lithium-rich and therefore highly conducting garnet solid electrolytes, the methodology has more general applicability, and therefore significant potential beyond the specific examples provided in the paper,” Bruce says. Commercialization may be needed to be demonstrate this approach at larger scale, he suggests.

    While the immediate impact of this work is likely to be on batteries, Rupp predicts another decade of exciting advances based on applications of her processing techniques to devices for neuromorphic computing, artificial intelligence, and fast gas sensors. “The moment the lithium is in a small solid-state film, you can use the fast motion to trigger other electrochemistry,” she says.

    Several companies have already expressed interest in using the new electrolyte approach. “It’s good for me to work with strong players in the field so they can push out the technology faster than anything I can do,” Rupp says.

    This work was funded by the MIT Lincoln Laboratory, the Thomas Lord Foundation, Competence Center Energy and Mobility, and Swiss Electrics.

    See the full article here .


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    The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

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  • richardmitnick 11:35 am on July 12, 2019 Permalink | Reply
    Tags: "Optimizing the Growth of Coatings on Nanowire Catalysts", , , Nanotechnology, ,   

    From Brookhaven National Lab: “Optimizing the Growth of Coatings on Nanowire Catalysts” 

    From Brookhaven National Lab

    July 8, 2019
    Ariana Manglaviti
    amanglaviti@bnl.gov
    (631) 344-2347

    Peter Genzer,
    genzer@bnl.gov
    (631) 344-3174

    1
    (Sitting from front) Iradwikanari Waluyo, Mingzhao Liu, Dario Stacchiola, (standing from front) Mehmet Topsakal, Mark Hybertsen, Deyu Lu, and Eli Stavitski at the Inner-Shell Spectroscopy beamline of Brookhaven Lab’s National Synchrotron Light Source II (NSLS-II). The scientists performed x-ray absorption spectroscopy experiments at NSLS-II to characterize the chemical state of titanium dioxide (titania) coatings on zinc oxide nanowires. They chemically processed the nanowires to make the coatings—which boost the efficiency of the nanowires in catalyzing the water-splitting reaction that produces oxygen and hydrogen, a sustainable fuel—more likely to adhere. These characterization results were coupled with electron microscopy imaging and theoretical analyses to generate a model of the amorphous (noncrystal) atomic structure of titania.

    Scientists chemically treated the surface of wire-looking nanostructures made of zinc oxide to apply a uniform coating of titanium dioxide; these semiconducting nanowires could be used as high-activity catalysts for solar fuel production.

    Solar energy harvested by semiconductors—materials whose electrical resistance is in between that of regular metals and insulators—can trigger surface electrochemical reactions to generate clean and sustainable fuels such as hydrogen. Highly stable and active catalysts are needed to accelerate these reactions, especially to split water molecules into oxygen and hydrogen. Scientists have identified several strong light-absorbing semiconductors as potential catalysts; however, because of photocorrosion, many of these catalysts lose their activity for the water-splitting reaction. Light-induced corrosion, or photocorrosion, occurs when the catalyst itself undergoes chemical reactions (oxidation or reduction) via charge carriers (electrons and “holes,” or missing electrons) generated by light excitation. This degradation limits catalytic activity.

    Now, scientists from the Center for Functional Nanomaterials (CFN)—a U.S. Department of Energy (DOE) Office of Science User Facility at Brookhaven National Laboratory—have come up with a technique for optimizing the activity of one such catalyst: 500-nanometer-long but relatively thin (40 to 50 nanometers) wire-looking nanostructures, or nanowires, made of zinc oxide (ZnO). Their technique—described in a paper published online in Nano Letters on May 3—involves chemically treating the surface of the nanowires in such a way that they can be uniformly coated with an ultrathin (two to three nanometers thick) film of titanium dioxide (titania), which acts as both a catalyst and protective layer.

    The CFN-led research is a collaboration between Brookhaven Lab’s National Synchrotron Light Source II (NSLS-II)—another DOE Office of Science User Facility— and Computational Science Initiative (CSI); the Center for Computational Materials Science at the Naval Research Laboratory; and the Department of Materials Science and Chemical Engineering at Stony Brook University.

    “Nanowires are ideal catalyst structures because they have a large surface area for absorbing light, and ZnO is an earth-abundant material that strongly absorbs ultraviolet light and has high electron mobility,” said co-corresponding author and study lead Mingzhao Liu, a scientist in the CFN Interface Science and Catalysis Group. “However, by themselves, ZnO nanowires do not have high enough catalytic activity or stability for the water-splitting reaction. Uniformly coating them with ultrathin films of titania, another low-cost material that is chemically more stable and more active in promoting interfacial charge transfer, enhances these properties to boost reaction efficiency by 20 percent compared to pure ZnO nanowires.”

    3
    (Background) A false-colored scanning electron microscope image of zinc oxide (ZnO) nanowires coated with titanium dioxide, or titania (TiO2). On average, the nanowires are 10 times longer than they are wide. The white-dashed inset contains a high-resolution transmission electron microscope image that distinguishes between the ZnO core and titania shell. The black-dashed inset features a structural model of the amorphous titania shell, with the red circles corresponding to oxygen atoms and the green and blue polyhedra corresponding to undercoordinated and coordinated titanium atoms, respectively.

    To “wet” the surface of the nanowires for the titania coating, the scientists combined two surface processing methods: thermal annealing and low-pressure plasma sputtering. For the thermal annealing, they heated the nanowires in an oxygen environment to remove defects and contaminants; for the plasma sputtering, they bombarded the nanowires with energetic oxygen gas ions (plasma), which ejected oxygen atoms from the ZnO surface.

    “These treatments modify the surface chemistry of the nanowires in such a way that the titania coating is more likely to adhere during atomic layer deposition,” explained Liu. “In atomic layer deposition, different chemical precursors react with a material surface in a sequential manner to build thin films with one layer of atoms at a time.”

    The scientists imaged the nanowire-shell structures with transmission electron microscopes at the CFN, shining a beam of electrons through the sample and detecting the transmitted electrons. However, because the ultrathin titania layer is not crystalline, they needed to use other methods to decipher its “amorphous” structure. They performed x-ray absorption spectroscopy experiments at two NSLS-II beamlines: Inner-Shell Spectroscopy (ISS) and In situ and Operando Soft X-ray Spectroscopy (IOS).

    “The x-ray energies at the two beamlines are different, so the x-rays interact with different electronic levels in the titanium atoms,” said co-author Eli Stavitski, ISS beamline physicist. “The complementary absorption spectra generated through these experiments confirmed the highly amorphous structure of titania, with crystalline domains limited to a few nanometers. The results also gave us information about the valence (charge) state of the titanium atoms—how many electrons are in the outermost shell surrounding the nucleus—and the coordination sphere, or the number of nearest neighboring oxygen atoms.”

    Theorists and computational scientists on the team then determined the most likely atomic structure associated with these experimental spectra. In materials with crystalline structure, the arrangement of an atom and its neighbors is the same throughout the crystal. But amorphous structures lack this uniformity or long-range order.

    “We had to figure out the correct combination of structural configurations responsible for the amorphous nature of the material,” explained co-corresponding author Deyu Lu, a scientist in the CFN Theory and Computation Group. “First, we screened an existing structural database and identified more than 300 relevant local structures using data analytics tools previously developed by former CFN postdoc Mehmet Topsakal and CSI computational scientist Shinjae Yoo. We calculated the x-ray absorption spectra for each of these structures and selected 11 representative ones as basis functions to fit our experimental results. From this analysis, we determined the percentage of titanium atoms with a particular local coordination.”

    The analysis showed that about half of the titanium atoms were “undercoordinated.” In other words, these titanium atoms were surrounded by only four or five oxygen atoms, unlike the structures in most common forms of titania, which have six neighboring oxygen atoms.

    To validate the theoretical result, Lu and the other theorists—Mark Hybertsen, leader of the CFN Theory and Computation Group; CFN postdoc Sencer Selcuk; and former CFN postdoc John Lyons, now a physical scientist at the Naval Research Lab—created an atomic-scale model of the amorphous titania structure. They applied the computational technique of molecular dynamics to simulate the annealing process that produced the amorphous structure. With this model, they also computed the x-ray absorption spectrum of titania; their calculations confirmed that about 50 percent of the titanium atoms were undercoordinated.

    “These two independent methods gave us a consistent message about the local structure of titania,” said Lu.

    “Fully coordinated atoms are not very active because they cannot bind to the molecules they do chemistry with in reactions,” explained Stavitski. “To make catalysts more active, we need to reduce their coordination.”

    “Amorphous titania transport behavior is very different from bulk titania,” added Liu. “Amorphous titania can efficiently transport both holes and electrons as active charge carriers, which drive the water-splitting reaction. But to understand why, we need to know the key atomic-scale motifs.”

    To the best of their knowledge, the scientists are the first to study amorphous titania at such a fine scale.

    “To understand the structural evolution of titania on the atomic level, we needed scientists who know how to grow active materials, how to characterize these materials with the tools that exist at the CFN and NSLS-II, and how to make sense of the characterization results by leveraging theory tools,” said Stavitski.

    Next, the team will extend their approach of combining experimental and theoretical spectroscopy data analysis to materials relevant to quantum information science (QIS). The emerging field of QIS takes advantage of the quantum effects in physics, or the strange behaviors and interactions that happen at ultrasmall scales. They hope that CFN and NSLS-II users will make use of the approach in other research fields, such as energy storage.

    This research used resources of Brookhaven Lab’s Scientific Data and Computing Center (part of CSI) and the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility operated by Lawrence Berkeley National Laboratory. The computational studies were in part supported by a DOE Laboratory Directed Research and Development (LDRD) project and the Office of Naval Research through the Naval Research Laboratory’s Basic Research Program.

    See the full article here .


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    BNL Campus


    BNL Center for Functional Nanomaterials

    BNL NSLS-II


    BNL NSLS II

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    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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  • richardmitnick 10:39 am on July 8, 2019 Permalink | Reply
    Tags: , , , Nanotechnology, The thickness of the tiny rectangular-shaped nanocrystals called nanoplatelets could be controlled with atomic precision., Tiny ‘greener’ nanocrystals that can be manipulated to produce high-quality pictures and lighting in electronic devices such as televisions.   

    From Curtin University: “Tiny nanocrystals create ‘brighter’ future for TV viewers, study finds” 

    From Curtin University

    8 July 2019

    Lucien Wilkinson
    Media Consultant
    Supporting Humanities and Science and Engineering
    Tel: +61 8 9266 9185
    Mob: +61 401 103 683
    lucien.wilkinson@curtin.edu.au

    Yasmine Phillips
    Media Relations Manager, Public Relations
    Tel: +61 8 9266 9085
    Mob: +61 401 103 877
    yasmine.phillips@curtin.edu.au

    Curtin University researchers have discovered tiny ‘greener’ nanocrystals that can be manipulated to produce high-quality pictures and lighting in electronic devices such as televisions.

    The research, published in the Journal of Physical Chemistry Letters, found that the thickness of the tiny rectangular-shaped nanocrystals, called nanoplatelets, could be controlled with atomic precision, and can be used to improve the brightness and colour performance displayed on an LCD screen.

    Lead researcher ARC DECRA Fellow Dr Guohua Jia, from Curtin’s School of Molecular and Life Sciences and the Curtin Institute for Functional Molecules and Interfaces, said manufacturers were constantly searching for products with unprecedented picture quality given the high demand and competition in the electronics industry.

    “A popular choice by consumers are quantum dot light emitting diodes (QLED) televisions, which use quantum dots to produce better brightness and a wider colour spectrum. The dots act like an activation layer when applied on a blue LED backlight, producing a more saturated and wider colour gamut,” Dr Jia said.

    “Our research explored whether we could improve the picture and lighting quality in similar electronic devices by creating a new form of nanocrystal. We were able to create these by using a wet-chemical, ‘bottom-up’ method, in which chemicals in their ionic phase react in a solvent in the presence of organic ligands such as amine.

    “Due to their unique shape and thickness, the nanocrystals produce colour that is much more pure. If they are used in electronic devices, they can greatly improve the lighting and picture quality by generating more vivid colours.”

    Dr Jia explained that the rectangular-shaped nanocrystals were non-toxic and ‘greener’ in comparison to other nanocrystals commonly used in similar devices and do not contain heavy-metal compounds.

    “The method that we invented can produce the nanocrystals in a large scale. This is valuable for industrial applications, as it can greatly improve the production of nanocrystals that can be used in electronic devices such as QLED televisions,” Dr Jia said.

    “The collaboration between several research groups around the world including Professor Chunsen Li from Chinese Academy of Sciences (CAS) and Dr Amit Sitt from Tel Aviv University in Israel, each with its unique capabilities and knowledge base, allowed us to tackle this unique problem both experimentally and theoretically, and may open the way for the development of new and exciting materials and technologies.

    “This research also underpinned a Patent Cooperation Treaty (PCT) application, and our team is looking for commercial and development partners to progress the commercialisation of this important research outcome.”

    The research was co-authored by researchers from the WA School of Mines: Minerals, Energy and Chemical Engineering at Curtin University, Chinese Academy of Sciences (CAS), The University of Western Australia and Tel Aviv University, in Israel.

    The research was funded by an Australian Research Council Discovery Early Career Researcher Award (ARC DECRA).

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Curtin University (formerly known as Curtin University of Technology and Western Australian Institute of Technology) is an Australian public research university based in Bentley and Perth, Western Australia. The university is named after the 14th Prime Minister of Australia, John Curtin, and is the largest university in Western Australia, with over 58,000 students (as of 2016).

    Curtin was conferred university status after legislation was passed by the Parliament of Western Australia in 1986. Since then, the university has been expanding its presence and has campuses in Singapore, Malaysia, Dubai and Mauritius. It has ties with 90 exchange universities in 20 countries. The University comprises five main faculties with over 95 specialists centres. The University formerly had a Sydney campus between 2005 & 2016. On 17 September 2015, Curtin University Council made a decision to close its Sydney campus by early 2017.

    Curtin University is a member of Australian Technology Network (ATN), and is active in research in a range of academic and practical fields, including Resources and Energy (e.g., petroleum gas), Information and Communication, Health, Ageing and Well-being (Public Health), Communities and Changing Environments, Growth and Prosperity and Creative Writing.

    It is the only Western Australian university to produce a PhD recipient of the AINSE gold medal, which is the highest recognition for PhD-level research excellence in Australia and New Zealand.

    Curtin has become active in research and partnerships overseas, particularly in mainland China. It is involved in a number of business, management, and research projects, particularly in supercomputing, where the university participates in a tri-continental array with nodes in Perth, Beijing, and Edinburgh. Western Australia has become an important exporter of minerals, petroleum and natural gas. The Chinese Premier Wen Jiabao visited the Woodside-funded hydrocarbon research facility during his visit to Australia in 2005.
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  • richardmitnick 1:04 pm on June 26, 2019 Permalink | Reply
    Tags: , Atomic electron tomography, , , Nanotechnology, Nucleation — capturing how the atoms rearrange at 4D atomic resolution,   

    From UCLA Newsroom: “Atomic motion is captured in 4D for the first time” 


    From UCLA Newsroom

    June 26, 2019
    Wayne Lewis

    Media Contact

    Nikki Lin
    310-206-8278
    nlin@cnsi.ucla.edu

    1
    The image shows 4D atomic motion captured in an iron-platinum nanoparticle at three different times. Alexander Tokarev

    Everyday transitions from one state of matter to another — such as freezing, melting or evaporation — start with a process called “nucleation,” in which tiny clusters of atoms or molecules (called “nuclei”) begin to coalesce. Nucleation plays a critical role in circumstances as diverse as the formation of clouds and the onset of neurodegenerative disease.

    A UCLA-led team has gained a never-before-seen view of nucleation — capturing how the atoms rearrange at 4D atomic resolution (that is, in three dimensions of space and across time). The findings, published in the journal Nature, differ from predictions based on the classical theory of nucleation that has long appeared in textbooks.

    “This is truly a groundbreaking experiment — we not only locate and identify individual atoms with high precision, but also monitor their motion in 4D for the first time,” said senior author Jianwei “John” Miao, a UCLA professor of physics and astronomy, who is the deputy director of the STROBE National Science Foundation Science and Technology Center and a member of the California NanoSystems Institute at UCLA.

    Research by the team, which includes collaborators from Lawrence Berkeley National Laboratory, University of Colorado at Boulder, University of Buffalo and the University of Nevada, Reno, builds upon a powerful imaging technique previously developed by Miao’s research group. That method, called “atomic electron tomography,” uses a state-of-the-art electron microscope located at Berkeley Lab’s Molecular Foundry, which images a sample using electrons. The sample is rotated, and in much the same way a CAT scan generates a three-dimensional X-ray of the human body, atomic electron tomography creates stunning 3D images of atoms within a material.

    Miao and his colleagues examined an iron-platinum alloy formed into nanoparticles so small that it takes more than 10,000 laid side by side to span the width of a human hair. To investigate nucleation, the scientists heated the nanoparticles to 520 degrees Celsius, or 968 degrees Fahrenheit, and took images after 9 minutes, 16 minutes and 26 minutes. At that temperature, the alloy undergoes a transition between two different solid phases.

    Although the alloy looks the same to the naked eye in both phases, closer inspection shows that the 3D atomic arrangements are different from one another. After heating, the structure changes from a jumbled chemical state to a more ordered one, with alternating layers of iron and platinum atoms. The change in the alloy can be compared to solving a Rubik’s Cube — the jumbled phase has all the colors randomly mixed, while the ordered phase has all the colors aligned.

    In a painstaking process led by co-first authors and UCLA postdoctoral scholars Jihan Zhou and Yongsoo Yang, the team tracked the same 33 nuclei — some as small as 13 atoms — within one nanoparticle.

    “People think it’s difficult to find a needle in a haystack,” Miao said. “How difficult would it be to find the same atom in more than a trillion atoms at three different times?”

    The results were surprising, as they contradict the classical theory of nucleation. That theory holds that nuclei are perfectly round. In the study, by contrast, nuclei formed irregular shapes. The theory also suggests that nuclei have a sharp boundary. Instead, the researchers observed that each nucleus contained a core of atoms that had changed to the new, ordered phase, but that the arrangement became more and more jumbled closer to the surface of the nucleus.

    Classical nucleation theory also states that once a nucleus reaches a specific size, it only grows larger from there. But the process seems to be far more complicated than that: In addition to growing, nuclei in the study shrunk, divided and merged; some dissolved completely.

    “Nucleation is basically an unsolved problem in many fields,” said co-author Peter Ercius, a staff scientist at the Molecular Foundry, a nanoscience facility that offers users leading-edge instrumentation and expertise for collaborative research. “Once you can image something, you can start to think about how to control it.”

    The findings offer direct evidence that classical nucleation theory does not accurately describe phenomena at the atomic level. The discoveries about nucleation may influence research in a wide range of areas, including physics, chemistry, materials science, environmental science and neuroscience.

    “By capturing atomic motion over time, this study opens new avenues for studying a broad range of material, chemical and biological phenomena,” said National Science Foundation program officer Charles Ying, who oversees funding for the STROBE center. “This transformative result required groundbreaking advances in experimentation, data analysis and modeling, an outcome that demanded the broad expertise of the center’s researchers and their collaborators.”

    Other authors were Yao Yang, Dennis Kim, Andrew Yuan and Xuezeng Tian, all of UCLA; Colin Ophus and Andreas Schmid of Berkeley Lab; Fan Sun and Hao Zeng of the University at Buffalo in New York; Michael Nathanson and Hendrik Heinz of the University of Colorado at Boulder; and Qi An of the University of Nevada, Reno.

    The research was primarily supported by the STROBE National Science Foundation Science and Technology Center, and also supported by the U.S. Department of Energy.

    See the full article here .


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    Please help promote STEM in your local schools.

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    UC LA Campus

    For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

    We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

    This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

     
  • richardmitnick 10:17 am on June 22, 2019 Permalink | Reply
    Tags: "Scientists make first high-res movies of proteins forming crystals in a living cell", , “The protein molecules are self-assembling building blocks and they will spontaneously form themselves into crystals No enzyme is required.”, , Microbial cell division, Nanotechnology, Single-molecule tracking, , Stimulated emission depletion, Super-resolution fluorescence microscopy   

    From SLAC National Accelerator Lab: “Scientists make first high-res movies of proteins forming crystals in a living cell” 

    From SLAC National Accelerator Lab

    June 21, 2019
    Glennda Chui

    A close-up look at how microbes build their crystalline shells has implications for understanding how cell structures form, preventing disease and developing nanotechnology.

    Scientists have made the first observations of proteins assembling themselves into crystals, one molecule at a time, in a living cell. The method they used to watch this happen – an extremely high-res form of molecular moviemaking ­– could shed light on other important biological processes and help develop nanoscale technologies inspired by nature.

    Led by researchers at Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory, the study was published in Nature Communications today.

    “I’ve been super-excited to watch and track the movements of single molecules as they form this fascinating crystalline shell on the surface of a microbe,” said Stanford professor and study co-author W.E. Moerner, who shared the 2014 Nobel Prize in chemistry for stunning advances in pushing the boundaries of what optical microscopes can see. “We can look on a very fine scale and see the molecules arranging themselves in the shell. It’s the first time we’ve been able to do this.”

    The study focused on a bacterium called Caulobacter crescentus that lives in lakes and streams. It’s one of many microbes that sport a very thin crystalline shell, known as a surface layer or S-layer, made of identical protein building blocks.

    2
    An Illustration shows the cylindrical stalk of the microbe covered in a crystalline protein shell known as an S-layer. (Greg Stewart/SLAC National Accelerator Laboratory)

    3
    This illustration zooms in to show six-sided protein crystal “tiles” forming at top left and far right. (Greg Stewart/SLAC National Accelerator Laboratory)

    Scientists have been trying to figure out what roles these brittle shells play in the lives of their owners and how they come together to smoothly cover a microbe’s curvy surfaces. The research is driven not just by a desire to understand how nature works, but also by the possibility of applying that knowledge to create new types of nanotechnology – for instance, by using the protein shells as scaffolds for building “engineered living materials.” The shells also offer a potential target for drugs aimed at disarming infectious bacteria.

    In this study, the research team used two established techniques that transcend the previous resolution limitations of optical microscopy – super-resolution fluorescence microscopy and single-molecule tracking – to watch individual building blocks move around the surfaces of living bacteria and assemble themselves into a shell. The resulting images and movies revealed how protein building blocks crystallize to form the bacterium’s S-layer coat.

    “It’s like watching a pile of bricks self-assemble into a two-story house,” said Jonathan Herrmann, a PhD student at Stanford and SLAC who along with fellow Stanford PhD students Colin Comerci and Josh Yoon carried out the bulk of the work.

    4
    A still image shows the tracks (red, white and blue lines) of individual protein molecules moving around the surface of a microbe over a period of 60 seconds. One of the molecules has just bound to an existing patch of the shell (bottom), which is labeled with a green fluorescent tag. The microbe is outlined in orange. (Josh Yoon, Colin Comerci, Jonathan Herrmann/Stanford University)


    This high-res movie represents the first observation ever made of protein crystallization by a living cell. It shows single protein molecules (red) roving over the surface of a microbe over the course of two minutes; when they join an existing patch of the microbe’s shell (green) they crystallize like rock candy around a string. The molecules are tagged with fluorescent chemicals to make them visible. (Josh Yoon, Colin Comerci, Jonathan Herrmann/Stanford University)

    Following the glow

    Protein crystals are widespread in nature: in shells that surround many bacteria and almost all of the ancient microbes called Archaea, in the outer shells of viruses and even in the human eye. The bacteria that cause anthrax and salmonella infections have these crystalline shells; so does Clostridium difficile, which causes serious infections of the colon and intestines. A lot of research has been aimed at disrupting these shells to head off infection.

    The bacteria in this study don’t infect healthy people and are well-studied and understood, so they make good research subjects. Scientists know, among other things, that these bacteria can’t thrive without their shells, which are made from protein building blocks called RsaA. But shell assembly takes place at such a tiny scale that it had never been observed before.

    To watch it happen, the researchers stripped microbes of their S-layers and supplied them with synthetic RsaA building blocks labeled with chemicals that fluoresce in bright colors when stimulated with a particular wavelength of light.

    5
    These images show how a super-resolution fluorescence microscopy technique called STED produces much sharper images of microbial shell assembly (right) than a previous technique, confocal microscopy (left). Areas in red are places where the shell is growing: at the ends of the microbial cell, in the pinched middle section where it is preparing to divide and at cracks and defects in the shell. (Colin Comerci, Jonathan Herrmann/Stanford University)

    Then they tracked the glowing building blocks with single-molecule microscopy as they formed a shell that covered the microbe in a hexagonal, tile-like pattern in less than two hours. A technique called stimulated emission depletion (STED) microscopy allowed them to see structural details of the layer as small as 60 to 70 nanometers, or billionths of a meter, across – about one-thousandth the width of a human hair.

    The team discovered that the shell-building didn’t happen the way they thought: The RsaA blocks were not guided into position and joined to the shell by enzymes, which promote most biological reactions. Instead they randomly moved around, found a patch of existing shell and joined it, like rock candy crystallizing around a string dipped in sugar water.

    “The protein molecules are self-assembling building blocks, and they will spontaneously form themselves into crystals,” Herrmann said. “No enzyme is required.”

    6
    An illustration shows how protein building blocks secreted by a microbe (at arrows) travel over its surface until they encounter its growing crystalline shell. There they join one of the six-sided units that tile the microbe’s surface, crystallizing like rock candy around a string. (Greg Stewart/SLAC National Accelerator Laboratory)

    A new way of seeing

    Since the flat crystalline shell can never perfectly fit the constantly changing 3-D shape of the microbe – “It’s not a huge leap to say that if you try to bend the sheet to fit the microbe, you have to break it,” Comerci said – there are always small defects and gaps in coverage, and those places, he said, are where they saw the shell grow.

    “For the first time,” he said, “we were able to watch the S-layer proteins do things on their own.”

    7
    Sketch showing where the microbe’s crystalline shell would be expected to crack, based on the curvature of its surface as it grows and prepares to divide. The predicted cracks and defects are shown here in white. These are places where the crystalline shell tends to grow. (Colin Comerci/Stanford University)

    8
    A closer look at areas where shell growth is occurring. Green areas are existing patches of shell; red areas are new growth at cracks, the ends (poles) of the microbial cell and in the middle, where the microbe is growing and preparing to divide. (Colin Comerci, Jonathan Herrmann/Stanford University)

    This new way of observing shell formation “is opening up a new way to understand and eventually manipulate surface layer structures, both in living organisms and in isolation,” said co-author Soichi Wakatsuki, a professor at SLAC and Stanford who leads the Biological Sciences Division at the lab’s Stanford Synchrotron Radiation Lightsource.

    SLAC/SSRL

    “Now that we know how they assemble, we can modify their properties so they can do specific types of work, like forming new types of hybrid materials or attacking biomedical problems.”

    The next step, researchers said, is to find out how the crystallization process starts using higher resolution X-ray and electron imaging available at SLAC: How do the very first bits of the shell crystallize without the equivalent of the rock candy string?

    Optical microscopy for this study was carried out at the Moerner lab at Stanford. Researchers from the University of British Columbia and from Professor Lucy Shapiro’s laboratory at Stanford also contributed to this work, which was funded in part by the National Institute of General Medical Sciences and the Chan Zuckerberg Biohub. Work in Wakatsuki’s labs at SLAC and Stanford was partly funded by a Laboratory Directed Research and Development grant from SLAC and by the DOE Office of Biological and Environmental Research. The Stanford Synchrotron Radiation Lightsource is a DOE Office of Science user facility.

    See the full article here .


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    SLAC/LCLS II projected view


    SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.

     
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