Computers Math

Medical devices, cars, and many advanced technologies contain innumerable delicate components that are held together by electrically conductive polymers, such as polyaniline. For several decades, synthesis of polyaniline for industrial electronics applications has faced a major limitation: what solvent best facilitates synthesis? This abstract question is important for minimizing the cost and complexity of polyaniline production and facilitating useful properties such as shaping. The ability to use a range of cheap, low-boiling-point solvents would greatly assist versatile polymer processing modes such as inkjet printing, but had remained elusive until now.
In a study recently published in Polymer-Plastics Technology and Materials, researchers from the University of Tsukuba and collaborating partners have synthesized polyaniline in various common solvents. This improved ability to synthesize and process polyaniline will greatly simplify production and lower manufacturing costs.
“Polyaniline is an extremely versatile polymer in routine and advanced technologies, but restrictions on which solvents can be used for synthesis have long hindered this versatility,” explains Professor Hiromasa Goto, senior author. “Our discovery of how to facilitate polymerization in diverse solvents will be useful in basic research and industrial applications.”
The researchers produced polyaniline from aniline sulfate in a single step when they added a small quantity of iodine to the reaction mixture. Many solvents were compatible with this procedure, including nontoxic ethanol as well as dichloromethane. Extensive instrumental characterizations demonstrated that the polyaniline produced by this method exhibited the crystallinity and electrical properties as if it had been prepared by conventional methods.
“A particularly exciting result is the ease of preparing industrially useful polymer alloys, such as blends with polystyrene or cellulose derivatives,” says Professor Goto. “Electrically conductive paint, advanced rubber blends, and other materials are now straightforward to prepare, which we expect will facilitate product development in diverse fields.”
What is it about the added iodine that facilitates polyaniline production? The researchers propose that iodine is an electron-acceptor dopant that facilitates production of localized polarons, which is critical to the subsequent polymerization by radical chain reactions.
The results of this study will help make polyaniline more compatible with inkjet printing and other useful processing technologies, and thus simplify production of printed circuit boards and other common components of modern electronics. By focusing on the rather abstract topic of solvent compatibility, many routine and advanced technologies will be easier to make at lower cost.
This work was supported by the Japan Society for the Promotion of Science (JSPS, Grants-in-Aid for Scientific Research (KAKENHI) [20K05626].
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Previous research has described how virtual training produces acute cognitive and neural benefits. Building on those results, a new study suggests that a similar virtual training can also reduce psychosocial stress and anxiety.
Researchers from Tohoku University’s Smart-Aging Research Center (IDAC) published their findings in the International Journal of Environmental Research and Public Health on May 23, 2022.
Physical exercise benefits our overall well-being. But for some — such as neurological patients, people suffering from cardiovascular disease, and hospitalized patients — physical exercise is not feasible, or even too dangerous. However, similar effects may be brought about using Immersive Virtual Reality (IVR).
Despite initially designed for entertainment, IVR has attracted interest from the academic community because of its potential use for clinical purposes, since it allows the user to experience a virtual world through a virtual body.
In the researchers’ previous study, they found that looking at a moving virtual body displayed in first-person perspective induces physiological changes. Heart rates increased/decreased coherently with the virtual movements, even though the young participants remained still. Consequently, acute cognitive and neural benefits occurred, just like after real physical activity.
In a followup study, the same benefits were also found on healthy elderly subjects after 20-minute sessions occurring twice a week for six weeks.
In the current study, the researchers explored the effect on stress, adding another level to the beneficial effects of virtual training. Young healthy subjects, while sitting still, experienced a virtual training displayed from the first-person perspective, creating the illusion of ownership over movements.
The avatar ran at 6.4 km/h for 30 minutes. Before and after the virtual training, the researchers induced and assessed the psychosocial stress response by measuring the salivary alpha-amylase — a crucial biomarker indicating the levels of neuroendocrine stress. Similarly, they distributed a subjective questionnaire for anxiety.
The results showed a decreased psychosocial stress response and lower levels of anxiety after the virtual training, comparable to what happens after real exercise.
“Psychosocial stress represents the stress experienced in frequent social situations such as social judgment, rejection, and when our performances get evaluated,” says Professor Dalila Burin, who developed the study. “While a moderate amount of exposure to stress might be beneficial, repeated and increased exposure can be detrimental to our health. This kind of virtual training represents a new frontier, especially in countries like Japan, where high performance demands and an aging population exist.”
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The creation of high-resolution extrusion printing — think 3D printing but with ink that conducts electricity — has enabled UBC researchers to explore the potential of wearable human motion devices.
Wearable technology — smartwatches, heart monitors, sleep aid devices, even step counters — have become part of everyday life. And researchers with UBC Okanagan’s Nanomaterials and Polymer Nanocomposites Laboratory, have created even smaller, lighter and highly-accurate sensors that can be integrated into clothing and equipment.
In collaboration with Drexel University and the University of Toronto, the UBCO research team is exploring a high-resolution extrusion printing approach to develop tiny devices with dual functionality — electromagnetic interference (EMI) shields and a body motion sensor.
Tiny and lightweight, these EMI shields can have applications in the health care, aerospace and automotive industries, explains Dr. Mohammad Arjmand, Assistant Professor and Canada Research Chair in Advanced Materials and Polymer Engineering at UBC Okanagan’s School of Engineering.
Using a two-dimensional inorganic nanomaterial called MXene, alongside a conductive polymer, Dr. Arjmand’s team has customized a conductive ink with a number of properties that make it easier to adapt into wearable technologies.
“Advanced or smart materials that provide electrical conductivity and flexibility are highly sought-after,” he says. “Extrusion printing of these conductive materials will allow for macro-scale patterning, meaning we can produce different shapes or geometries, and the product will have outstanding architecture flexibility.”
Currently, manufacturing technologies of these functional materials are mostly limited to laminated and unsophisticated structures that don’t enable the integration of monitoring technologies, explains doctoral student Ahmadreza Ghaffarkhah.
“These printed structures can be seeded with micro-cracks to develop highly sensitive sensors. Tiny cracks in their structures are used to track small vibrations in their surroundings,” says Ghaffarkhah. “These vibrations can monitor a multitude of human activities, including breathing, facial movements, talking as well as the contraction and relaxation of a muscle.”
By going back to the drawing board, the UBCO researchers were able to address a major challenge encountered by extrusion printing. Previously, the technology didn’t allow for high-enough printing resolution, so it was difficult to manufacture highly precise structures.
“Compared to conventional manufacturing technologies, extrusion printing offers customization, reduction in materials waste, and rapid production, while opening up numerous opportunities for wearable and smart electronics,” explains Dr. Arjmand. “As extrusion printing techniques improve, it is opening the door to many unique innovations.”
The researchers continue to investigate additional applications for extrusion printing inks that go beyond EMI shields and wearable electronics.
The research was published in Carbon, with financial support from a Natural Sciences and Engineering Research Council of Canada Alliance Grant and Zentek Limited. More

A quantum simulator at Rice University is giving physicists a clear look at spin-charge separation, the quantum world’s version of the magician’s illusion of sawing a person in half.
Published this week in Science, the research has implications for quantum computing and electronics with atom-scale wires.
Electrons are minuscule, subatomic particles that cannot be divided. Despite this, quantum mechanics dictates that two of their attributes — spin and charge — travel at different speeds in one-dimensional wires.
Rice physicists Randy Hulet, Ruwan Senaratne and Danyel Cavazos built an ultracold venue where they could repeatedly view and photograph a pristine version of this quantum spectacle, and they collaborated with theorists from Rice, China, Australia and Italy on the published results.
Quantum simulators exploit quantum properties of real objects like atoms, ions or molecules to solve problems that are difficult or impossible to solve with conventional computers. Rice’s spin-charge simulator uses lithium atoms as stand-ins for electrons and a channel of light in place of a 1D electronic wire.
The universe is awash in heat that obscures the quantum behavior of atoms. To perceive quantum effects in lithium, Hulet’s team used laser cooling to make its atoms 1 million times colder than the coldest natural object in the universe. Additional lasers created the 1D light channel, or optical waveguide. More

A team of UCLA engineers and their colleagues have developed a new design strategy and 3D printing technique to build robots in one single step.
A study that outlined the advance, along with the construction and demonstration of an assortment of tiny robots that walk, maneuver and jump, was published in Science.
The breakthrough enabled the entire mechanical and electronic systems needed to operate a robot to be manufactured all at once by a new type of 3D printing process for engineered active materials with multiple functions (also known as metamaterials). Once 3D printed, a “meta-bot” will be capable of propulsion, movement, sensing and decision-making.
The printed metamaterials consist of an internal network of sensory, moving and structural elements and can move by themselves following programmed commands. With the internal network of moving and sensing already in place, the only external component needed is a small battery to power the robot.
“We envision that this design and printing methodology of smart robotic materials will help realize a class of autonomous materials that could replace the current complex assembly process for making a robot,” said the study’s principal investigator Xiaoyu (Rayne) Zheng, an associate professor of civil and environmental engineering, and of mechanical and aerospace engineering at the UCLA Samueli School of Engineering. “With complex motions, multiple modes of sensing and programmable decision-making abilities all tightly integrated, it’s similar to a biological system with the nerves, bones and tendons working in tandem to execute controlled motions.”
The team demonstrated the integration with an on-board battery and controller for the fully autonomous operation of the 3D printed robots — each at the size of a finger nail. According to Zheng, who is also a member of the California NanoSystems Institute at UCLA, the methodology could lead to new designs for biomedical robots, such as self-steering endoscopes or tiny swimming robots, which can emit ultrasounds and navigate themselves near blood vessels to deliver drug doses at specific target sites inside the body. More

Scientists from the University of Tsukuba demonstrated how ultrafast spectroscopy can be used to improve the temporal resolution of quantum sensors. By measuring the orientation of coherent spins inside a diamond lattice, they showed that magnetic fields can be measured even over very short times. This work may allow for the advancement of the field of ultra-high accuracy measurements known as quantum metrology, as well as “spintronic” quantum computers that operate based on electron spins.
Quantum sensing offers the possibility of extremely accurate monitoring of temperature, as well as magnetic and electric fields, with nanometer resolution. By observing how these properties affect the energy level differences within a sensing molecule, new avenues in the field of nanotechnology and quantum computing may become viable. However, the time resolution of conventional quantum sensing methods has previously been limited to the range of microseconds due to limited luminescence lifetimes. A new approach is needed to help refine the quantum sensing.
Now, a team of researchers led by the University of Tsukuba developed a new method for implementing magnetic field measurements in a well-known quantum sensing system. Nitrogen-vacancy (NV) centers are specific defects in diamonds in which two adjacent carbon atoms have been replaced by a nitrogen atom and a vacancy. The spin state of an extra electron at this site can be read or coherently manipulated using pulses of light.
“For example, the negatively charged NV spin state can be used as a quantum magnetometer with an all-optical readout system, even at room temperature,” first author Ryosuke Sakurai says. The team used an “inverse Cotton-Mouton” effect to test their method. The normal Cotton-Mouton effect occurs when a transverse magnetic field creates birefringence, which can change linearly polarized light into having an elliptical polarization. In this experiment, the scientists did the opposite, and used light of different polarizations to create tiny controlled local magnetic fields.
“With nonlinear opto-magnetic quantum sensing, it will be possible to measure local magnetic fields, or spin currents, in advanced materials with high spatial and temporal resolution,” senior author Muneaki Hase and his colleague Toshu An at the Japan Advanced Institute of Science and Technology, say. The team hopes that this work will help enable quantum spintronic computers that are sensitive spin states, not just electrical charge as with current computers. The research may also enable new experiments to observe dynamic changes in magnetic fields or possibly even single spins under realistic device-operating conditions.
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Scholars from the Max Planck Institute for Evolutionary Anthropology in Germany and the University of Auckland in New Zealand have created a new global repository of linguistic data. The project is designed to facilitate new insights into the evolution of words and sounds of the languages spoken across the world today. The Lexibank database contains standardized lexical data for more than 2000 languages. It is the most extensive publicly available collection compiled so far.
Is it true that many languages in the world use words similar to “mama” and “papa” for “mother” and “father”? If a language uses only one word for both “arm” and “hand,” does it also use only one word for both “leg” and “foot”? How do languages manage to use a relatively small number of words to express so many concepts? An interdisciplinary team of linguists, computational scientists and psychologists have created a large public database that can be used to study these and many more questions with the help of computational methods.
“When our Department of Linguistic and Cultural Evolution was founded in 2014, I presented my colleagues with an ambitious goal: there are more than 7000 languages in the world. Create databases with the most extensive documentation of the linguistic diversity as possible,” says Max Planck Director Russell Gray. “Our inspiration came from Genbank — a large genetic database where biologists from all over the world have deposited genomic data,” Gray continues. “Genbank was a game changer. The large amount of freely available sequence data revolutionized the ways we can analyze biological diversity. We hope that the first of our global linguistic databases, Lexibank, will help start to revolutionize our knowledge of linguistic diversity in a similar way.”
New standards and new software
The Lexibank repository provides data in the form of standardized wordlists for more than 2000 language varieties. “The work on Lexibank coincided with a push towards more consistent data formats in linguistic databases. Thus Lexibank can serve both as a large-scale example of the benefits of standardization and a catalyst for further standardization,” reports Robert Forkel, who led the computational part of the data collection. “We decided to create our own standards, called Cross-Linguistic Data Formats, which have now been used successfully in a multitude of projects in which our department is involved.”
The new standards proposed by the team are accompanied by new software tools that greatly facilitate linguists’ workflows. “We have designed new computer-assisted workflows that enable existing language datasets to be made comparable,” says Johann-Mattis List, who led the practical part of the data curation. “With these workflows, we have dramatically increased the efficiency of data standardization and data curation.”
Identifying patterns of language evolution
In addition to collecting and sharing the standardized language data, the authors also designed new computational techniques to answer questions about the evolution of linguistic diversity. They illustrate how these methods can be used by computing how languages differ or agree with respect to sixty different features.
“Thanks to our standardized representation of language data, it is now easy to check how many languages use words like’mama’ and ‘papa’ for ‘mother’ and ‘father’,” reports List. “It turns out that this pattern can indeed be found in many languages of the world and in very different regions,” adds Simon J. Greenhill, one of the founders of the Lexibank project. “Since all the languages with this pattern are not closely related to each other, it reflects independent parallel evolution, just as the great linguist Roman Jakobson suggested in 1968.”
Expanding the data and developing new methods
The new data collection, and the automatically computed language features will contribute to new insights into open questions on linguistic diversity and language evolution. “Nobody thinks that the analysis must stop with the examples we give in our paper,” says List. “On the contrary, we hope that linguists, psychologists, and evolutionary scientists will feel encouraged to build on our example by expanding the data and developing new methods,” adds Forkel.
Even in their current study, the authors present findings that warrant future investigations. “When investigating which languages use the same word for ‘arm’ and ‘hand’, we found that these languages typically also use the same word for ‘leg’ and ‘foot’,” List reports. “While this may seem to be a silly coincidence, it shows that the lexicon of human languages is often much more structured than one might assume when investigating one language in isolation.” More

The semiconductor industry has been growing steadily ever since its first steps in the mid-twentieth century and, thanks to the high-speed information and communication technologies it enabled, it has given way to the rapid digitalization of society. Today, in line with a tight global energy demand, there is a growing need for faster, more integrated, and more energy-efficient semiconductor devices.
However, modern semiconductor processes have already reached the nanometer scale, and the design of novel high-performance materials now involves the structural analysis of semiconductor nanofilms. Reflection high-energy electron diffraction (RHEED) is a widely used analytical method for this purpose. RHEED can be used to determine the structures that form on the surface of thin films at the atomic level and can even capture structural changes in real time as the thin film is being synthesized!
Unfortunately, for all its benefits, RHEED is sometimes hindered by the fact that its output patterns are complex and difficult to interpret. In virtually all cases, a highly skilled experimenter is needed to make sense of the huge amounts of data that RHEED can produce in the form of diffraction patterns. But what if we could make machine learning do most of the work when processing RHEED data?
A team of researchers led by Dr. Naoka Nagamura, a visiting associate professor at Tokyo University of Science (TUS) and a senior researcher of National Institute for Materials Science (NIMS), Japan, has been working on just that. In their latest study, published online on 09 June 2022 in the international journal Science and Technology of Advanced Materials: Methods, the team explored the possibility of using machine learning to automatically analyze RHEED data. This work, which was supported by JST-PRESTO and JST-CREST, was the result of joint research by TUS and NIMS, Japan. It was co-authored by Ms. Asako Yoshinari, Prof. Masato Kotsugi also from TUS, and Dr. Yuma Iwasaki from NIMS.
The researchers focused on the surface superstructures that form on the first atomic layers of clean single-crystal silicon (one of the most versatile semiconductor materials). depending on the amount of indium atoms adsorbed and slight differences in temperature. Surface superstructures are atomic arrangements unique to crystal surfaces where atoms stabilize in different periodic patterns than those inside the bulk of the crystal, depending on differences in the surrounding environment. Because they often exhibit unique physical properties, surface superstructures are the focus of much interest in materials science.
First, the team used different hierarchical clustering methods, which are aimed at dividing samples into different clusters based on various measures of similarity. This approach serves to detect how many different surface superstructures are present. After trying different techniques, the researchers found that Ward’s method could best track the actual phase transitions in surface superstructures.
The scientists then sought to determine the optimal process conditions for synthesizing each of the identified surface superstructures. They focused on the indium deposition time for which each superstructure was most extensively formed. Principal component analysis and other typical methods for dimensionality reduction did not perform well. Fortunately, non-negative matrix factorization, a different clustering and dimensionality reduction technique, could accurately and automatically obtain the optimal deposition times for each superstructure. Excited about these results, Dr. Nagamura remarks, “Our efforts will help automate the work that typically requires time-consuming manual analysis by specialists. We believe our study has the potential to change the way materials research is done and allow scientists to spend more time on creative pursuits.”
Overall, the findings reported in this study will hopefully lead to new and effective ways of using machine learning technique for materials science — a central topic in the field of materials informatics. In turn, this would have implications in our everyday lives as existing devices and technologies are upgraded with better materials. “Our approach can be used to analyze the superstructures grown not only on thin-film silicon single-crystal surfaces, but also metal crystal surfaces, sapphire, silicon carbide, gallium nitride, and various other important substrates. Thus, we expect our work to accelerate the research and development of next-generation semiconductors and high-speed communication devices,” concludes Dr. Nagamura.
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