Scanning tunneling microscopes image materials with atomic precision and are versatile. Researchers have therefore been using them for many years to explore the world of the nanocosmos. Physicists at Forschungszentrum Jülich have now optimized such a device for the study of quantum effects. Thanks to magnetic cooling, their scanning tunneling microscope has no moving parts and operates at extremely low temperatures of up to 30 millikelvin with virtually no vibration. In the future, the instrument can help researchers unlock the unusual properties of quantum materials that are critical to the development of quantum computers and sensors.
The region near absolute zero is particularly exciting for physics. Thermal fluctuations are minimized at the low temperatures. The laws of quantum physics come into play, revealing special properties of materials. Electric current then flows losslessly without any resistance. Another example is so-called superfluidity: Individual atoms fuse into a collective state and move past each other without friction.
Such extremely low temperatures are also the necessary prerequisite for exploring and harnessing quantum effects for quantum computing. Researchers worldwide, including those at Forschungszentrum Jülich, are currently pursuing this goal at full speed. Quantum computers could be vastly superior to conventional supercomputers for certain tasks. But development is still in its infancy. A key challenge is finding materials and processes that make complex architectures with stable quantum bits possible.
“I believe a versatile microscope like ours is the tool of choice for this fascinating task because it allows imaging and manipulating matter at the level of individual atoms and molecules in a variety of ways.”
– Ruslan Temirov of Forschungszentrum Jülich
Over years of work, he and his team have equipped a scanning tunneling microscope with magnetic cooling for this purpose. “Our new microscope differs from all the others in much the same way that an electric car differs from a combustion engine,” explains the Jülich physicist. Until now, people relied on a kind of liquid fuel, a mixture of two helium isotopes, to bring microscopes to such low temperatures. “During operation, this cooling mixture continuously circulates through thin tubes, which leads to increased background noise,” Temirov says.
The Jülich microscope’s cooling device, on the other hand, is based on the adiabatic demagnetization process. The principle is not new. It was already used in the 1930s to realize temperatures below 1 Kelvin in the laboratory for the first time. “To cool the device, we only change the strength of the electric current flowing through an electromagnetic coil. Our microscope therefore has no moving parts, and operates virtually vibration-free,” reports Ruslan Temirov.
The Jülich team is the first to design a scanning tunneling microscope using this technology. “The new cooling technology has several advantages in practice. Not only does the imaging quality benefit, but the operation of the instrument and the entire setup are simplified,” says institute director Stefan Tautz. With its modular design, the Jülich quantum microscope is also open to technical advances, he adds, because upgrades can be easily implemented. “Adiabatic cooling is a real quantum leap for scanning tunneling microscopy. The advantages are so significant that we are now developing a commercial prototype as the next step,” explains Stefan Tautz. Quantum technologies are currently the focus of research. The interest of numerous research groups in such an instrument is therefore likely to be assured.
Structural analysis with machine learning reveals tactics of SARS-CoV-2 virus
In the ability of the virus, the proteins of the SARS Cov-2 virus play a key role in tricking human immune defenses and replicating in patient cells. An international research team with the participation of the Technical University of Munich (TUM) has now compiled the most comprehensive and detailed overview of all 3D structures of the virus proteins available worldwide to date. The evaluation with artificial intelligence methods revealed surprising findings.
How does the SARS-CoV-2 virus manage to evade immune defenses and replicate in the cells of patients? To answer this question, an international research team has assembled the most comprehensive overview of any analysis of the exact three-dimensional shape of SARS-CoV-2 proteins – including the well-known spike protein – available to date.
To compile this overview, the team used high-throughput machine learning. This approach makes it possible to predict structural states of coronavirus proteins based on analyses of related proteins. The database now consists of 2,060 3D models with atomic resolution. All structural models are freely available on the Aquaria-COVID website (https://aquaria.ws/covid).
“This provides an unprecedented level of detail that will help researchers better understand the molecular mechanisms of COVID-19 infection and develop therapies to combat the pandemic, for example by identifying potential new targets for future treatments or vaccines.”
– Burkhard Rost, Chair of Bioinformatics at the TU Munich
The structural map unlocks the compiled knowledge
In a second part of the study, a complementary approach known as human-in-the-loop machine learning was used. Here, a novel visual interface was generated that summarizes everything that is currently known about the three-dimensional shape of SARS-CoV-2 proteins – and what is not.
Researchers can also use the visual interface as a navigation tool to find appropriate structural models for specific research questions. Work with the models has already provided some important clues about how coronaviruses manage to take command in our cells.
How coronaviruses manage to take command in our cells
Using machine learning algorithms, the team identified three coronavirus proteins (NSP3, NSP13, and NSP16) that “mimic” human proteins and successfully fool host cells into thinking they are endogenous proteins working in the best interest of the cell.
Modeling also revealed five coronavirus proteins (NSP1, NSP3, spike glycoprotein, envelope protein, and ORF9b protein) that “misappropriate” or disrupt processes in human cells. In this way, the virus manages to take control, complete its life cycle and spread.
Understanding how the virus works – and how to stop it
“In analyzing these structural models, we also found new clues about how the virus copies its own genome – which is the key process that enables the virus to spread rapidly in infected individuals,” says Burkhard Rost. “The findings from our study bring us closer to understanding how the virus works and what we can do to stop it.”
“The longer the virus circulates, the greater the risk that it will mutate and form new variants like the delta strain,” says Sean O’Donoghue, lead author of the study and a professor at the Garvan Institute in Sydney. “Our resource will help researchers understand how new strains of the virus differ from each other – a piece of the puzzle we hope will help combat emerging variants.”
Research in the field of organic batteries
The so-called redox flow batteries (RFB) represent a promising concept for the storage of renewable electrical energy. In this type of battery, which is particularly suitable for stationary applications, the energy is stored in tanks with liquid electrolytes, while the power is determined by the area of the cells. RFBs based on vanadium salts as the energy carrier are particularly well developed. They are already used in numerous plants. However, vanadium also accounts for a significant proportion of the total cost of the battery, so cheaper alternatives are being sought.
One possibility is the transition from metal salts as energy carriers to organic molecules. Because of the wide variety of possible compounds, some of which can be produced from renewable raw materials, organic RFBs have been the subject of intensive research for several years. An important issue still to be resolved is the long-term stability of the organic energy carriers, which, unlike inorganic salts, can decompose during the electrochemical processes. A whole series of scientific questions also remain to be resolved with regard to the details of the processes at the carbon electrodes.
Over the next two years, Luis Fernando Arenas will be investigating organic redox flow batteries in Professor Thomas Turek’s research group at the Energy Storage Technologies Research Center (EST) of the Clausthal University of Technology in Goslar. Various projects on the development of vanadium-based RFBs have been carried out there in recent years, and the working group has extensive test facilities for measuring the performance data of RFB components such as electrodes, membranes and bipolar plates. The principles and methods developed in this work will now be applied to organic redox flow batteries.
Luis Fernando Arenas is a technical chemist who earned his master’s degree in 2013 from the University of Coahuila in Mexico. He then moved to the University of Southampton, where he obtained his PhD in 2017 in the renowned research group of Professor Frank C. Walsh with a thesis on RFB based on zinc and cerium.
Since then, he has continued as a visiting scientist at the University of Southampton and is a member of the Executive Committee of the Electrochemical Technology Group of the Society of Chemical Industry. He is also involved with the National Institute of Electricity and Clean Energy (INEEL) in Cuernavaca, Mexico, and consults for companies in the electrochemical industry, including chlor-alkali companies in Monterrey, Mexico. In 2019, he was awarded the Schwäbisch Gmünd Prize of the European Academy of Surface Technology.
Efficient vacuum generator as compact version with integrated silencer
Across the industry, vacuum generation finds a wide variety of applications: from packaging and palletizing, to material handling and automatic assembly, to automated transport and pick-and-place. Here, process engineers face the challenge of achieving a small and lightweight machine design without sacrificing performance. To meet these high demands, SMC has now further developed its ZH-A series vacuum generator as a compact version. Thanks to a reduction in overall volume, this is a true lightweight and still has a larger total volume flow – ideal for use in mobile handling applications.
Whether in the semiconductor, electrical, automotive or food industries, in life science as well as a wide range of manufacturing and assembly equipment: Vacuum generators are part of the indispensable standard repertoire for a wide variety of applications – and must meet growing demands. To this end, SMC, the specialist in pneumatic and electrical automation, has developed a compact version of its vacuum generators. This provides process engineers with a solution that allows them to achieve an even more compact machine design while offering high performance with easy installation and maintenance. A particular advantage is that the reduction in weight improves efficiency, as robots, for example, can perform faster movements without compromising process reliability.
Small on the outside, powerful on the inside
SMC engineers have put the ZH-A series vacuum generator on a diet, creating a compact version. By reducing the connection height by up to 20% (-4.6 mm) and the total volume by up to 39% (-14.1 cm3), it is not only significantly more compact, enabling smaller and more cost-effective machine designs. The weight has also been reduced by up to 59% (-19.4 g) compared with its predecessor. This is now only between 28.7 g (1.5 mm nozzle Ø) and 46.4 g (1.8 mm nozzle Ø). Overall, this means that more output can be placed on the same area, which reduces the CO2 footprint and investment costs. On the other hand, faster cycle times can be realized thanks to the lower moment of inertia, which increases the output quantity.
At the same time, SMC has not skimped on performance: for example, the maximum achievable vacuum is -90 kPa and the maximum suction volume flow, depending on the nozzle size, is 78 l/m (1.5 mm nozzle Ø),128 l/min (1.8 mm nozzle Ø) and 155 l/min (2.0 mm nozzle Ø) – an increase of 11% for the smallest nozzle size compared to its predecessor. This enables faster evacuation when handling workpieces while at the same time increasing reliability and again shortening cycle times. An integrated silencer also ensures that venting noise is reduced, thus improving work safety.
Flexible installation and easy to distinguish
The compact version product is easy to install on different machine designs thanks to three mounting options: Process engineers can choose between direct mounting, mounting with L-fastener or DIN rail mounting. The same applies to the connection either as a plug-in connection or screw connection (G-/Rc-/NPT-thread) or as a combination between the two connection options.
In order to also comply with the Poka Yoke principle, the pressure ring has a color coding that immediately distinguishes between metric sizes (light gray) and inch sizes (orange). This not only makes it easy to identify the product, but also complies with the specifications of the US market, for example. Since the bore spacing for fasteners is the same as for the predecessor, the compact version of the series can be replaced without any problems – so nothing stands in the way of a machine update.