2023年度のドイツ語インテンシブコースを開催します。詳細はドイツ語インテンシブコース案内資料を参照してください。

• ドイツ語インテンシブ募集要項

Discovery of Structural Regularity Hidden in Silica Glass

Glass – whether used to insulate our homes or as the screens in our computers and smartphones – is a fundamental material. Yet, despite its long usage throughout human history, the disordered structure of its atomic configuration still baffles scientists, making understanding and controlling its structural nature challenging. It also makes it difficult to design efficient functional materials made from glass.

To uncover more about the structural regularity hidden in glassy materials, a research group has focused on ring shapes in the chemically bonded networks of glass. The group, which included Professor Motoki Shiga from Tohoku University’s Unprecedented-scale Data Analytics Center, and Professor Akihiko Hirata from Waseda University created new ways in which to quantify the rings’ three-dimensional structure and structural symmetries: “roundness” and “roughness.”

Using these indicators enabled the group to determine the exact number of representative ring shapes in crystalline and glassy silica (SiO₂), finding a mixture of rings unique to glass and ones that resembled the rings in the crystals.

Additionally, the researchers developed a technique to measure the spatial atomic densities around rings by determining the direction of each ring.

They revealed that there is anisotropy around the ring, i.e., that the regulation of the atomic configuration is not uniform in all directions, and that the structural ordering related to the ring-originated anisotropy is consistent with experimental evidence, like the diffraction data of SiO₂. It was also revealed that there were specific areas where the atomic arrangement followed some degree of order or regularity, even though it appeared to be a discorded and chaotic arrangement of atoms in glassy silica.

“The structural unit and structural order beyond the chemical bond had long been assumed through experimental observations but its identification has eluded scientists until now,” says Shiga. “Furthermore, our successful analysis contributes to understanding phase-transitions, such as vitrification and crystallization of materials, and provides the mathematical descriptions necessary for controlling material structures and material properties.”

Looking ahead, Shiga and his colleagues will use these techniques to come up with procedures for exploring glass materials, procedures that are based on data-driven approaches like machine learning and AI.

Their findings were published open access in the journal Communication Materials on November 3, 2023.

<Publication Details>

Title: Ring-originated anisotropy of local structural ordering in amorphous and crystalline silicon dioxide
Authors: Motoki Shiga, Akihiko Hirata, Yohei Onodera, and Hirokazu Masai
Journal: Communications Materials
DOI: 10.1038/s43246-023-00416-w

Understanding the Dynamic Behavior of Rubber Materials

Researchers present a novel experimental system for simultaneous measurement of dynamic mechanical properties and X-ray computed tomography

Rubber-like materials can exhibit both spring-like and flow-like behaviors simultaneously, which contributes to their exceptional damping abilities. To understand the dynamic viscoelasticity of these materials, researchers from Japan have recently developed a novel system that can conduct dynamic mechanical analysis and dynamic micro X-ray computed tomography simultaneously. This technology can enhance our understanding of the microstructure of viscoelastic materials and pave the way for the development of better materials.

Rubber-like materials, commonly used in dampeners, possess a unique property known as dynamic viscoelasticity, enabling them to convert mechanical energy from vibrations into heat while exhibiting spring-like and flow-like behaviors simultaneously. Customization of these materials is possible by blending them with compounds of specific molecular structures, depending on the dynamic viscosity requirements.

However, the underlying mechanisms behind the distinct mechanical properties of these materials remain unclear. A primary reason for this knowledge gap has been the absence of a comprehensive system capable of simultaneously measuring the mechanical properties and observing the microstructural dynamics of these materials. While X-ray computed tomography (CT) has recently emerged as a promising option for a non-destructive inspection of the internal structure of materials down to nano-scale resolutions, it is not suited for observation under dynamic conditions.

Against this backdrop, a team of researchers, led by Associate Professor (tenure-track) Masami Matsubara from the School of Creative Science and Engineering at the Faculty of Engineering at Waseda University in Japan, has now developed an innovative system that can conduct dynamic mechanical analysis and dynamic micro X-ray CT imaging simultaneously. Their study was made available online on October 19, 2023 and will be published in Volume 205 of the journal Mechanical Systems and Signal Processing on December 15, 2023.

“By integrating X-ray CT imaging performed at the large synchrotron radiation facility Spring-8(BL20XU) and mechanical analysis under dynamic conditions, we can elucidate the relationship between a material’s internal structure, its dynamic behavior, and its damping properties,” explains Dr. Matsubara. At the core of this novel system is the dynamic micro X-ray CT and a specially designed compact shaker developed by the team that is capable of precise adjustment of vibration amplitude and frequency.

The team utilized this innovative system to investigate the distinctions between styrene-butadiene rubber (SBR) and natural rubber (NR), as well as to explore how the shape and size of ZnO particles influence the dynamic behavior of SBR composites.

The researchers conducted dynamic micro X-ray CT scans on these materials, rotating them during imaging while simultaneously subjecting them to vibrations from the shaker. They then developed histograms of local strain amplitudes by utilizing the local strains extracted from the 3D reconstructed images of the materials’ internal structures. These histograms, in conjunction with the materials’ loss factor, a measure of the inherent damping of a material, were analyzed to understand their dynamic behavior.

When comparing materials SBR and NR, which have significantly different loss factors, the team found no discernible differences between their local strain amplitude histograms. However, the histograms displayed wider strain distributions in the presence of composite particles like ZnO. This suggests that strain within these materials is non-uniform and depends on the shape and size of the particles, which may have masked any changes from the addition of the particles.

“This technology can allow us to study the microstructure of rubber and rubber-like materials under dynamic conditions and can result in the development of fuel-efficient rubber tires or gloves that do not deteriorate. Moreover, this technology can also enable the dynamic X-ray CT imaging of living organs that repeatedly deform, such as the heart, and can even pave the way for the development of artificial organs,” says Dr. Matsubara, highlighting the importance of this study.

Overall, this breakthrough technology has the potential to advance the understanding of the microstructure of viscoelastic materials, likely opening the doors for the development of novel materials with improved properties.

Reference

About Waseda University

Located in the heart of Tokyo, Waseda University is a leading private research university that has long been dedicated to academic excellence, innovative research, and civic engagement at both the local and global levels since 1882. The University has produced many changemakers in its history, including nine prime ministers and many leaders in business, science and technology, literature, sports, and film. Waseda has strong collaborations with overseas research institutions and is committed to advancing cutting-edge research and developing leaders who can contribute to the resolution of complex, global social issues. The University has set a target of achieving a zero-carbon campus by 2032, in line with the Sustainable Development Goals (SDGs) adopted by the United Nations in 2015.

To learn more about Waseda University, visit https://www.waseda.jp/top/en

About Associate Professor Masami Matsubara

Masami Matsubara is an Associate Professor (tenure-track) at the School of Creative Science and Engineering of the Faculty of Science and Engineering at Waseda University, Japan. He earned his Ph.D. from Doshisha University. His research focuses on the mechanics of materials, mechatronics, and dynamic modelling. He has recently worked on vibration reduction methods and dynamic design for large-scale numerical analysis models and detailed design and experimental methods for component and unit testing. He is a member of the Japan Society of Mechanical Engineers (JSME) and SAE International. He received the JSME Medal for Outstanding Paper in 2014, 2020, and 2022.

文部科学省卓越大学院プログラム
「パワー・エネルギー・プロフェッショナル育成プログラム」
2024年1月実施の7期生(2024年進入・編入)選抜試験(SE)に関する情報更新致しました。

理工HP大学院入試ページの中のPEPSE情報ページ（募集要項・出願書類）
https://www.waseda.jp/fsci/admissions_gs/guidelines/pep/

Direct Power Generation from Methylcyclohexane Using Solid Oxide Fuel Cells

Researchers have successfully generated electricity directly from methylcyclohexane, an organic hydride, using solid oxide fuel cells, with lower energy than conventional catalytic dehydrogenation reactions.

Methylcyclohexane is very promising as a hydrogen carrier that can safely and efficiently transport and store hydrogen. However, the dehydrogenation process using catalysts has issues due to its durability and large energy loss. Recently, Japanese researchers have succeeded in using solid oxide fuel cells to generate electricity directly from methylcyclohexane and recover toluene for reuse. This research is expected to not only reduce energy requirements but also explore new chemical synthesis by fuel cells.

Methylcyclohexane (MCH), a type of organic hydride, is expected to be an excellent hydrogen carrier because it remains liquid at room temperature, is easy to transport, has low toxicity, and has a higher hydrogen density than high-pressure hydrogen. Dehydrogenation—the process of removing hydrogen atoms from molecules—in the presence of a catalyst, yields hydrogen and the byproduct toluene, which can then be used to generate electricity to produce CO2-free power. However, the dehydrogenation reaction is an endothermic reaction, and energy loss as well as the facilities required for the reaction are issues.

Recently, a team of researchers from Japan, led by Professor Akihiko Fukunaga from the Department of Applied Chemistry at Waseda University, has succeeded in generating electricity directly from MCH using solid oxide fuel cells (SOFC). Their work was made available online on July 4, 2023 in Volume 348 of Applied Energy.

The research team tried to perform two processes simultaneously in a fuel cell: dehydrogenation from organic hydrides, which is an endothermic reaction, and electricity generation, which is an exothermic reaction. To achieve this, they used an anode-supported solid oxide fuel cell with a higher operating temperature than that of a polymer electrolyte fuel cell. They operated it at a temperature that did not allow pyrolysis of organic hydrides and under conditions that prevented carbon deposition at the electrodes. The production ratio of toluene to benzene was 94:6. This achievement demonstrated the possibility of generating electricity without using dehydrogenation facilities which were conventionally required and using less energy than that required for dehydrogenation reactions using catalysts.
In addition, “It was elucidated that by changing the conditions, oxygen groups could be introduced into the aromatic skeleton using a fuel cell” reveals Fukunaga.

These results indicate that the MHC reacts with the conducting oxygen ions in the SOFC to successfully generate electricity. Thus, power can be generated directly from MHC, and the energy required for direct power generation is lesser than that required for the conventional catalyst-assisted dehydrogenation reaction of MCH.

“Fuel cells have been studied and developed as devices that produce highly efficient, carbon-free electricity through the electrochemical reaction of hydrogen and oxygen. In this study, we have demonstrated that this device can be applied to control dehydrogenation reactions from organic hydrides and oxygen substitution reactions of aromatic rings. In the future, new synthetic chemistry may be created by applying fuel cells.” concludes Fukunaga. Here’s hoping that the proposed technology will pave the way to a sustainable hydrogen-based society!

Reference

Authors

Akihiko Fukunaga¹, Asami Kato¹, Yuki Hara¹, and Takaya Matsumoto

Title of original paper

Dehydrogenation of Methylcyclohexane Using Solid Oxide Fuel Cell – A Smart Energy Conversion

Journal

Applied Energy

DOI

10.1016/j.apenergy.2023.121469

Affiliations

¹ Department of Applied Chemistry, Waseda University

About Waseda University

Located in the heart of Tokyo, Waseda University is a leading private research university that has long been dedicated to academic excellence, innovative research, and civic engagement at both the local and global levels since 1882. The University has produced many changemakers in its history, including nine prime ministers and many leaders in business, science and technology, literature, sports, and film. Waseda has strong collaborations with overseas research institutions and is committed to advancing cutting-edge research and developing leaders who can contribute to the resolution of complex, global social issues. The University has set a target of achieving a zero-carbon campus by 2032, in line with the Sustainable Development Goals (SDGs) adopted by the United Nations in 2015.

To learn more about Waseda University, visit https://www.waseda.jp/top/en

About Professor Akihiko Fukunaga

Dr. Akihiko Fukunaga is a Faculty of Science and Engineering at the School of Advanced Science and Engineering at Waseda University in Japan. He received his Ph.D. from Waseda University in 1999 and has been a Professor of Applied Chemistry there since 2019. Prior to that, he worked at JXTG Nippon Oil & Energy Corporation from 1984 to 2019, where he successfully commercialized the residential fuel cell system, EneFarm. His research interests include energy materials, hydrogen, fuel cells, and carbon recycling.

A Novel, Completely Solid, Rechargeable Air Battery

 A benzoquinone-based negative electrode and solid Nafion polymer electrolyte are used in this first-of-its-kind battery

Solid-state batteries use solid electrodes and solid electrolytes, unlike the more commonly known lithium-ion batteries, which use liquid electrolytes. Solid-state batteries overcome various challenges associated with liquid-based batteries, such as flammability, limited voltage, unstable reactants, and poor long-term cyclability and strength. Making advances in this field, researchers recently demonstrated an all-solid-state rechargeable air battery composed of a redox-active organic negative electrode and a proton-conductive polymer electrolyte.

Metals are typically used as active materials for negative electrodes in batteries. Recently, redox-active organic molecules, such as quinone- and amine-based molecules, have been used as negative electrodes in rechargeable metal–air batteries with oxygen-reducing positive electrodes. Here, protons and hydroxide ions participate in the redox reactions. Such batteries exhibit high performance, close to the maximum capacity that is theoretically possible. Furthermore, using redox-active organic molecules in rechargeable air batteries overcomes problems associated with metals, including the formation of structures called ‘dendrites,’ which impact battery performance, and have negative environmental impact. However, these batteries use liquid electrolytes—just like metal-based batteries—which pose major safety concerns like high electrical resistance, leaching effects, and flammability.

Now, in a new study published in Angewandte Chemie International Edition on May 2, 2023, a group of Japanese researchers have developed an all-solid-state rechargeable air battery (SSAB) and investigated its capacity and durability. The study was led by Professor Kenji Miyatake from Waseda University and the University of Yamanashi, and co-authored by Professor Kenichi Oyaizu from Waseda University.

The researchers chose a chemical called 2,5-dihydroxy-1,4-benzoquinone (DHBQ) and its polymer poly(2,5-dihydroxy-1,4-benzoquinone-3,6-methylene) (PDBM) as active materials for the negative electrode due to their stable and reversible redox reactions in acidic conditions. In addition, they utilized a proton-conductive polymer called Nafion as the solid electrolyte, thereby replacing conventional liquid electrolytes. “To the best of my knowledge, no air batteries based on organic electrodes and solid polymer electrolyte have been developed yet,” says Miyatake.

After the SSAB was in place, the researchers experimentally assessed its charge–discharge performance, rate characteristics, and cyclability. They found that unlike typical air batteries that use a metallic negative electrode and an organic liquid electrolyte, the SSAB did not deteriorate in the presence of water and oxygen. Furthermore, replacing the redox-active molecule DHBQ with its polymeric counterpart PDBM formed a better negative electrode. While the per gram-discharge capacity of the SSAB-DHBQ was 29.7 mAh, the corresponding value of the SSAB-PDBM was 176.1 mAh, at a constant current density of 1 mAcm^-2.

The researchers also found that the coulombic efficiency of SSAB-PDBM was 84% at 4 C rate, which gradually decreased to 66% at 101 C rate. While the discharge capacity of SSAB-PDBM reduced to 44% after 30 cycles, by increasing the proton-conductive polymer content of the negative electrode, the researchers could significantly improve it to 78%. Electron microscopic images confirmed that the addition of Nafion improved the performance and durability of the PDBM-based electrode.

This study demonstrates the successful operation of an SSAB comprising redox-active organic molecules as the negative electrode, a proton-conductive polymer as the solid electrolyte, and an oxygen-reducing, diffusion type positive electrode. The researchers hope that it will pave the way for further advancements. “This technology can extend the battery life of small electronic gadgets such as smartphones and eventually contribute to realizing a carbon-free society,” concludes Miyatake.

Reference

Authors

Makoto Yonenaga¹, Yusuke Kaiwa², Kouki Oka^2,3, Kenichi Oyaizu², and Kenji Miyatake¹

Title of original paper

All-Solid-State Rechargeable Air Batteries Using Dihydroxybenzoquinone and Its Polymer as the Negative Electrode

Journal

Angewandte Chemie International Edition

DOI

10.1002/anie.202304366

Affiliations

¹Clean Energy research Center, Fuel Cell Nanomaterials Center, University of Yamanashi
²Department of Applied Chemistry, Research Institute for Science and Engineering, Waseda University
³Center for Future Innovation (CFI) and Department of Applied Chemistry, Graduate School of Engineering, Osaka University

Funding Information

This work was partly supported by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan, through Grants-in-Aid for Scientific Research (18H05515, 23H02058), MEXT Program: Data Creation and Utilization Type Material Research and Development Project (JPMXP1122712807), and JKA promotion funds from AUTORACE.

About Waseda University

Located in the heart of Tokyo, Waseda University is a leading private research university that has long been dedicated to academic excellence, innovative research, and civic engagement at both the local and global levels since 1882. The University has produced many changemakers in its history, including nine prime ministers and many leaders in business, science and technology, literature, sports, and film. Waseda has strong collaborations with overseas research institutions and is committed to advancing cutting-edge research and developing leaders who can contribute to the resolution of complex, global social issues. The University has set a target of achieving a zero-carbon campus by 2032, in line with the Sustainable Development Goals (SDGs) adopted by the United Nations in 2015.

To learn more about Waseda University, visit https://www.waseda.jp/top/en

About Professor Kenji Miyatake

Kenji Miyatake received his Ph.D. degree in chemistry from Waseda University in 1996. He was a Japan Society for the Promotion of Science (JSPS) postdoctoral fellow at McGill University from 1999 to 2001. In 2001, he was offered an associate professor position at the Clean Energy Research Center at the University of Yamanashi, where he currently serves as a professor. He also holds a professor position in his alma mater since 2020. He is also a Fellow of the Royal Society of Chemistry.

Novel, Highly Sensitive Biosensor Set to Transform Wearable Health Monitoring

Researchers from Japan have developed a new wearable biosensor that can detect extremely small changes in tear glucose and blood lactate levels

Wearable wireless biosensors are an integral part of digital healthcare and monitoring. Commonly used chipless resonant antenna-based biosensors are simple and affordable, but have limited applicability due to their low sensitivity. Now, researchers from Japan have developed a novel, wireless, parity–time symmetry-based bioresonator that can detect minute concentrations of tear glucose and blood lactate. This highly sensitive, tunable, and robust bioresonator has the potential to revolutionize personalized health monitoring and digitized healthcare systems.

Researchers have developed a novel, wireless, PT-symmetric wearable resonator that can detect tear glucose and blood lactate levels in the micromolar range. The resonator is composed of an inductance–capacitance–resistance (LCR) reader and an LCR sensor with an enzyme-based chemiresistor. The setup has a high quality (Q) factor, making it highly sensitive.

Wireless wearable biosensors have been a game changer in personalized health monitoring and healthcare digitization because they can efficiently detect, record, and monitor medically significant biological signals. Chipless resonant antennae are highly promising components of wearable biosensors, as they are affordable and tractable. However, their practical applications are limited by low sensitivity (inability to detect small biological signals) caused by low quality (Q) factor of the system.

To overcome this hurdle, researchers led by Professor Takeo Miyake from Waseda University, Professor Yin Sijie from Beijing Institute of Technology, and Taiki Takamatsu from Japan Aerospace Exploration Agency, have developed a wireless bioresonator using “parity–time (PT) symmetry” that can detect minute biological signals. Their work has been published in Advanced Materials Technologies.

In this study, the researchers designed a bioresonator consisting of a magnetically coupled reader and sensor with high Q factor, and thus, increased sensitivity to biochemical changes. The reader and sensor both comprise an inductor (L) and capacitor (C) that are parallel-connected to a resistor (R). In the sensor, the resistor is a chemical sensor called a “chemiresistor” that converts biochemical signals into changes in resistance. The chemiresistor contains an enzymatic electrode with an immobilized enzyme. Minute biochemical changes at the enzymatic electrode (in response to changes in the levels of biomolecules such as blood sugar or lactate) are thus converted into electrical signals by the sensor, and then amplified at the reader.

Explaining the technical concept behind their novel biosensor, Miyake says, “We modeled the characteristics of the PT-symmetric wireless sensing system by using an eigenvalue solution and input impedance, and experimentally demonstrated the sensitivity enhancement at/near the exceptional point by using parallel inductance–capacitance–resistance (LCR) resonators. The developed amplitude modulation-based PT-symmetric bioresonator can detect small biological signals that have been difficult to measure wirelessly until now. Moreover, our PT-symmetric system provides two types of readout modes: threshold-based switching and enhanced linear detection. Different readout modes can be used for different sensing ranges.”

The researchers tested the system (here containing a glucose-specific enzyme) on human tear fluids and found that it could detect glucose concentrations ranging from 0.1 to 0.6 mM. They also tested it with a lactate-specific enzyme and commercially available human skin and found that it could measure lactate levels in the range of 0.0 to 4.0 mM through human skin tissue, without any loss of sensitivity. This result further indicates that the biosensor can be used as an implantable device. Compared to a conventional chipless resonant antenna-based system, the PT-symmetric system achieved a 2000-fold higher sensitivity in linear and a 78% relative change in threshold-based detection respectively.

Sharing his vision for the future, Miyake concludes, “The present telemetry system is robust and tunable. It can enhance the sensitivity of sensors to small biological signals. We envision that this technology can be used for developing smart contact lenses to detect tear glucose and/or implantable medical devices to detect lactate for efficient monitoring of diabetes and blood poisoning.”

This novel PT-symmetric wireless wearable bioresonator may soon usher in a new era of personalized health monitoring and efficient digitized healthcare systems!

Reference

Title of original paper: Wearable, Implantable, Parity-Time Symmetric Bioresonators for Extremely Small Biological Signal Monitoring
DOI: 10.1002/admt.202201704
Journal: Advanced Materials Technologies
Article Publication Date: 08 April 2023
Authors: Taiki Takamatsu¹, Yin Sijie¹, Takeo Miyake^1,2
Affiliations:
¹ Faculty of Science and Engineering, Graduate School of Information, Production and Systems, Waseda University, Japan
² PRESTO, Japan Science and Technology Agency, Japan

A Sowing, Pruning, and Harvesting Robot for Synecoculture^TM Farming

Researchers develop a four-wheeled, two orthogonal axes mechanism robot to maintain plants grown under solar panels

Synecoculture, a new farming method, involves growing mixed plant species together in high density. However, it requires complex operation since varying species with different growing seasons and growing speeds are planted on the same land. To address this need, researchers have developed a robot that can sow, prune, and harvest plants in dense vegetation grown. Its small, flexible body will help large-scale Synecoculture. This is an important step towards achieving sustainable farming and carbon neutrality.

Synecoculture is a new agricultural method advocated by Dr. Masatoshi Funabashi, senior researcher at Sony Computer Science Laboratories, Inc. (Sony CSL), in which various kinds of plants are mixed and grown in high density, establishing rich biodiversity while benefiting from the self-organizing ability of the ecosystem. However, such dense vegetation requires frequent upkeep—seeds need to be sown, weeds need to be pruned, and crops need to be harvested. Synecoculture thus requires a high level of ecological literacy and complex decision-making. And while the operational issues present with Synecoculture can be addressed by using an agricultural robot, most existing robots can only automate one of the above three tasks in a simple farmland environment, thus falling short of the literacy and decision-making skills required of them to perform Synecoculture. Moreover, the robots may make unnecessary contact with the plants and damage them, affecting their growth and the harvest.

With the rising awareness of environmental issues, such a gap between the performance of humans versus that of conventional robots has spurred innovation to improve the latter.

A group of researchers led by Takuya Otani, an Assistant Professor at Waseda University, in collaboration with Sustainergy Company and Sony CSL, have designed a new robot that can perform Synecoculture effectively. The robot is called SynRobo, with “syn” conveying the meaning of “together with” humans. It manages a variety of mixed plants grown in the shade of solar panels, an otherwise unutilized space. An article describing their research was published in Volume 13, Issue 1 of Agriculture, on 21 December 2022. This article has been co-authored by Professor Atsuo Takanishi, also from Waseda University, other researchers of Sony CSL, and students from Waseda University.

Otani briefly explains the novel robot’s design. “It has a four-wheel mechanism that enables movement on uneven land and a robotic arm that expands and contracts to help overcome obstacles. The robot can move on slopes and avoid small steps. The system also utilizes a 360^o camera to recognize and maneuver its surroundings. In addition, it is loaded with various farming tools—anchors (for punching holes), pruning scissors, and harvesting setups. The robot adjusts its position using the robotic arm and an orthogonal axes table that can move horizontally.”  

Besides these inherent features, the researchers also invented techniques for efficient seeding. They coated seeds from different plants with soil to make equally-sized balls. These made their shape and size consistent, so that the robot could easily sow seeds from multiple plants. Furthermore, an easy-to-use, human-controlled maneuvering system was developed to facilitate the robot’s functionality. The system helps it operate tools, implement automatic sowing, and switch tasks.

The new robot could successfully sow, prune, and harvest in dense vegetation, making minimal contact with the environment during the tasks because of its small and flexible body. In addition, the new maneuvering system enabled the robot to avoid obstacles 50% better while reducing its operating time by 49%, compared to a simple controller.

“This research has developed an agricultural robot that works in environments where multiple species of plants grow in dense mixtures,” Otani tells us. “It can be widely used in general agriculture as well as Synecoculture—only the tools need to be changed when working with different plants. This robot will contribute to improving the yield per unit area and increase farming efficiency. Moreover, its agricultural operation data will help automate the maneuvering system. As a result, robots could assist agriculture in a plethora of environments. In fact, Sustainergy Company is currently preparing to commercialize this innovation in abandoned fields in Japan and desertified areas in Kenya, among other places.”

Such advancements will promote Synecoculture farming, with the combination of renewable energy, and help solve various pressing problems, including climate change and the energy crisis. The present research is a crucial step toward achieving sustainable agriculture and carbon neutrality. Here’s hoping for a smart and skillful robot that efficiently supports large-scale Synecoculture!

Reference

Authors: Takuya Otani¹, Akira Itoh², Hideki Mizukami², Masatsugu Murakami², Shunya Yoshida², Kota Terae², Taiga Tanaka², Koki Masaya², Shuntaro Aotake^2,3, Masatoshi Funabashi³, and Atsuo Takanishi²

Title of original paper: Agricultural Robot under Solar Panels for Sowing, Pruning, and Harvesting in a Synecoculture Environment

Journal: Agriculture

DOI: 10.3390/agriculture13010018

Affiliations: 1: Waseda Research Institute for Science and Engineering, Waseda University, 2: Faculty of Science and Engineering, Waseda University, 3: Sony Computer Science Laboratories, Inc., Tokyo

About Professor Takuya Otani from Waseda Research Institute for Science and Engineering

Takuya Otani is an Assistant Professor at the Faculty of Science and Engineering at Waseda Research Institute for Science and Engineering. He received his Ph.D. degree from Waseda University in 2016. He is a member of the Virtual Reality Society of Japan, Japanese Council of IFToMM, Japan Society of Mechanical Engineers, Robotics Society of Japan, and IEEE. He received the Waseda e-Teaching Good Practice Award in 2021. His research interests include robotics and intelligent system, intelligent robotics, haptics, humanoid robotics, and mechanics and mechatronics. His recent work involves developing efficient robots for Synecoculture agriculture.

About Waseda University

Located in the heart of Tokyo, Waseda University is a leading private research university that has long been dedicated to academic excellence, innovative research, and civic engagement at both the local and global levels since 1882. The University has produced many changemakers in its history, including nine prime ministers and many leaders in business, science and technology, literature, sports, and film. Waseda has strong collaborations with overseas research institutions and is committed to advancing cutting-edge research and developing leaders who can contribute to the resolution of complex, global social issues. The University has set a target of achieving a zero-carbon campus by 2032, in line with the Sustainable Development Goals (SDGs) adopted by the United Nations in 2015.

To learn more about Waseda University, visit https://www.waseda.jp/top/en

About Synecoculture

Synecoculture is a method of farming that produces useful plants while making multifaceted use of the self-organizing ability of the earth’s ecosystem. Advocated by Dr. Masatoshi Funabashi of Sony Computer Science Laboratories, Inc., it is characterized by a comprehensive ecosystem utilization method that considers not only food production but also the impacts on the environment and health.

*”Synecoculture” is a registered trademark or a trademark of Sony Group Corporation.

About Sustainergy Company

Sustainergy Company, a Tokyo-based renewable-energy startup, its management philosophy is “making the world sustainable through energy”, has been developing and operating solar power generation projects in Japan, including large-scale farm-based solar power generation (Agrivoltaics). The company noticed that the space under the solar panels of many solar power plants is underutilized and thought that if Sony CSL’s Synecoculture farming method could be applied to the semi-shaded area under the solar panels, the degraded soil could be restored, and the land could be turned into greenery and farmland, thereby enabling both food production and renewable energy production on the same land. Sustainergy Company is preparing to commercialize this project in abandoned farmlands in Japan, desertified areas in Kenya, and other countries. To learn more about Sustainergy Company, visit https://sustainergy.co.jp/.

Researchers successfully record the phase distribution of electrons, unveiling the detailed structure of its complex wavefunction

The structure, dynamics, and functions of materials are predominantly determined by their constituent electrons. Owing to their quantum nature, electrons have “wave”-like characteristics. However, measuring the phase of an electron and its complex electron wavefunction is challenging. Using state-of-the-art attosecond technology, researchers at Waseda University and National Research Council of Canada have now successfully recorded the phase distribution of electrons ejected from a neon atom, allowing a complete, detailed visualization of the complex electron wavefunction.

The early 20^th century saw the advent of quantum mechanics to describe the properties of small particles, such as electrons or atoms. Schrödinger’s equation in quantum mechanics can successfully predict the electronic structure of atoms or molecules. However, the “duality” of matter, referring to the dual “particle” and “wave” nature of electrons, remained a controversial issue. Physicists use a complex wavefunction to represent the wave nature of an electron. “Complex” numbers are those that have both “real” and “imaginary” parts—the ratio of which is referred to as the “phase”. However, all directly measurable quantities must be “real”. This leads to the following challenge: when the electron hits a detector, the “complex” phase information of the wavefunction disappears, leaving only the square of the amplitude of the wavefunction (a “real” value) to be recorded. This means that electrons are detected only as particles, which makes it difficult to explain their dual properties in atoms.

The ensuing century witnessed a new, evolving era of physics, namely, attosecond physics. The attosecond is a very short time scale, a billionth of a billionth of a second. “Attosecond physics opens a way to measure the phase of electrons. Achieving attosecond time-resolution, electron dynamics can be observed while freezing molecular motion,” explains Professor Hiromichi Niikura from the Department of Applied Physics, Waseda University, Japan, who, along with Professor D. M. Villeneuve—a principal research scientist at the Joint Attosecond Science Laboratory, National Research Council, and adjunct professor at University of Ottawa—pioneered the field of attosecond physics. Niikura and Villeneuve had previously developed a breakthrough method, attosecond re-collision, and also demonstrated the imaging of a molecular orbital or electron wavefunction in a molecule.

In a recent study published in Volume 106 Issue 6 (2022; page 063513) of Physical Review A on 23 December, 2022, these researchers employed another approach involving attosecond physics, using an attosecond laser pulse, or high-harmonic generation, to visualize a complex wavefunction. The attosecond laser pulse consists of coherent light with a wavelength much shorter than ultra-violet, referred to as extreme ultra-violet (EUV) light. When this pulse irradiates a gas, an electron is ejected. This process is referred to as photoionization. The attosecond pulse consists of a set of “harmonics” or different colors of light. By controlling the generation of the attosecond pulse, the researchers isolated two photoionization pathways—one consisting of a particular harmonic, and the other consisting of another harmonic along with an infrared pulse—to ionize neon. The electron wavefunctions produced by both pathways can interfere with each other. The interference pattern varies with the attosecond delay between the harmonics and the IR pulses. The team determined the phase and amplitude distributions of the photoelectron from the interference pattern and visualized its complex wavefunction. As the energy resolution is smaller than the bandwidth of the attosecond pulses, the researchers were successful in visualizing the detailed wavefunction structure. Furthermore, the researchers developed a method of disentangling the measured wavefunction into wavefunctions that are produced by individual ionization pathways.

Now that the researchers have successfully visualized the complex wavefunction of an electron—something that cannot be seen through conventional photoelectron spectroscopy—there’s so much more they can achieve! Niikura says, “Nowadays, photoelectron spectroscopy using EUV and X-ray has become a basic tool for investigating structures and dynamics of materials. The present method will provide a way to elucidate the quantum properties of electrons.” Visualizing the complete, detailed, complex electron wavefunction will be of significant impact in the fields of nanotechnology, chemistry, and molecular biology.

Reference

Authors: Takashi Nakajima¹, Tasuku Shinoda¹, D. M. Villeneuve² and Hiromichi Niikura¹
Title of original paper: High-resolution attosecond imaging of an atomic electron wavefunction in momentum space
Journal: Physical Review A
DOI: 10.1103/PhysRevA.106.063513
Latest Article Publication Date: 23 December, 2022
Affiliations: ¹Department of Applied Physics, Waseda University, Japan
²Joint Attosecond Science Laboratory, National Research Council and University of Ottawa, Ontario, Canada

Image

Image title: Visualizing complex photoelectron wavefunctions using attosecond imaging technology
Image caption: Researchers measure the phase and amplitude of the complex electron wavefunctions (a,b), represented by color (or hue) for phase and brightness (or value) for amplitude (plotted in logarithmic scale), in the hue-saturation-value (HSV) color map, as shown in (c).
Image credits: Hiromichi Niikura from Waseda University
License type: Original content

About Professor Hiromichi Niikura from Waseda University

Hiromichi Niikura is a Professor at the Department of Applied Physics, Waseda University. He obtained his bachelors from Kyoto Institute of Technology, masters from Graduate School of Kyoto Institute of Technology, and Ph.D. from Graduate University for Advanced Studies, Institute for Molecular Science, Japan. His research focuses on atomic, molecular, and optical (AMO) physics. He has worked at National Research Council of Canada (2000-2009), where he conducted a pioneering work in attosecond physics, a new emerging field. Niikura was awarded the prestigious Japan Society for Promotion of Science (JSPS) award in 2012. Professor Niikura can be contacted at [email protected].

Discovering Rare Red Spiral Galaxy Population from Early Universe with the James Webb Space Telescope

The first image of NASA’s James Webb Space Telescope reveals a detailed morphology of highly redshifted spiral galaxies

Morphology of galaxies contain important information about the process of galaxy formation and evolution. With its state-of-the-art resolution, NASA’s James Webb Space Telescope has now captured several red spiral galaxies in its first image at an unprecedented resolution. Researchers from Waseda University have now analyzed these galaxies, revealing that these are among the furthest known spiral galaxies till date. The analysis further detected a passive red spiral galaxy in the early universe, a surprising discovery.

Spiral galaxies represent one of the most spectacular features in our universe. Among them, spiral galaxies in the distant universe contain significant information about their origin and evolution. However, we have had a limited understanding of these galaxies due to them being too distant to study in detail. “While these galaxies were already detected among the previous observations using NASA’s Hubble Space Telescope and Spitzer Space Telescope, their limited spatial resolution and/or sensitivity did not allow us to study their detailed shapes and properties,” explains Junior Researcher Yoshinobu Fudamoto from Waseda University in Japan, who has been researching galaxies’ evolution.

Now, NASA’s James Webb Space Telescope (JWST) has taken things to the next level. In its very first imaging of the galaxy cluster, SMACS J0723.3-7327, JWST has managed to capture infrared images of a population of red spiral galaxies at an unprecedented resolution, revealing their morphology in detail!

Against this backdrop, in a recent article published in The Astrophysical Journal Letters on 21 October 2022, a team of researchers comprising Junior Researcher Yoshinobu Fudamoto, Prof. Akio K. Inoue, and Dr. Yuma Sugahara from Waseda University, Japan, has revealed surprising insights into these red spiral galaxies. Among the several red spiral galaxies detected, the researchers focused on the two most extremely red galaxies, RS13 and RS14. Using spectral energy distribution (SED) analysis, the researchers measured the distribution of energy over wide wavelength range for these galaxies. The SED analysis revealed that these red spiral galaxies belong to the early universe from a period known as the “cosmic noon” (8-10 billion years ago), which followed the Big Bang and the “cosmic dawn.” Remarkably, these are among the farthest known spiral galaxies till date.

Rare, red spiral galaxies account for only 2% of the galaxies in the local universe. This discovery of red spiral galaxies in the early universe, from the JWST observation covering only an insignificant fraction of space, suggests that such spiral galaxies existed in large numbers in the early universe.

The researchers further discovered that one of the red spiral galaxies, RS14, is a “passive” (not forming stars) spiral galaxy, contrary to the intuitive expectation that galaxies in the early universe would be actively forming stars. This detection of a passive spiral galaxy in the JWST’s limited field of view is particularly surprising, since it suggests that such passive spiral galaxies could also exist in large numbers in the early universe.

Overall, the findings of this study significantly enhances our knowledge about red spiral galaxies, and the universe as a whole. “Our study showed for the first time that passive spiral galaxies could be abundant in the early universe. While this paper is a pilot study about spiral galaxies in the early universe, confirming and expanding upon this study would largely influence our understanding of the formation and evolution of galactic morphologies,” concludes Fudamoto.

Reference

Title of original paper: Red Spiral Galaxies at Cosmic Noon Unveiled in the First JWST Image
DOI: 10.3847/2041-8213/ac982b
Journal: The Astrophysical Journal Letters
Article Publication Date: October 21, 2022
Authors: Yoshinobu Fudamoto^1,2, Akio K. Inoue^1,3, and Yuma Sugahara^1,2
Affiliations:
¹Waseda Research Institute for Science and Engineering, Faculty of Science and Engineering, Waseda University
²National Astronomical Observatory of Japan
³Department of Physics, School of Advanced Science and Engineering, Faculty of Science and Engineering, Waseda University

【PEP卓越大学院プログラム】
2023年1月実施SE (2023年4月進入・編入）選抜試験　募集要項等情報更新致しました。(2022.09.28)
https://www.waseda.jp/fsci/admissions_gs/guidelines/pep/　よりご確認ください。

WasedaUniversity-jobopening

【Faculty job openings】Department of Computer Science and Engineering

*English version follows Japanese

5/2に2022年度春学期分学費引落が成立しなかった場合は、7/1の第2回の学費引落にてお支払いください。

• 振替結果については、ご自身で通帳等にてご確認ください。
• 6月下旬に口座振替通知書（ハガキ）を発送の上、引落を行います。
• 休学の場合を除いて、請求額に変更はありません（追加料金等は発生しません）。
• 5/2の引落が成立しなかったことにより、直ちに退学になることはありません。
• 口座情報や学費負担者情報の変更を行う場合は、5月中をめどにご対応ください。
• 私費留学生の場合は、別途4/13に海外送金などに関する案内メールをお送りしていますので、ご確認ください。海外送金もしくはクレジットカード払いを希望の場合は、学費の支払い期日が通常とは異なります。詳細はメールに記載された通りです。

なお、2022年4月入学者は入学手続時に既に春学期分学費を納入済みのため、今回の引落の対象外となります（秋学期から引落が開始されます）。また、国の修学支援制度採用者や延長生の場合は、原則7/1が初回の請求日となります。
上記をはじめ、学費に関する詳細はこちらよりご確認ください。

In case the bank transfer for the tuition and fees for the AY2022 spring semester was not successful on May 2, please make your payment at the second bank transfer scheduled on July 1.

• Please confirm the result of the transfer in your bankbook, etc.
• The transfer will be made after sending a notification for bank transfer in the late June.
• There will be no change in the total amount (no additional fees, etc. will be charged), except in case of a student taking a leave of absence.
• You will not be immediately dismissed from the school due to the unsuccessful result of the transfer on May 2.
• If you wish to change your debit account or tuition payer information, please take necessary procedures by the end of May.
• If you are a privately financed international student, please check the separate information e-mail sent on April 13. If you wish a payment by international remittance or credit card, the due day differs from the originally planned. Please refer to the e-mail carefully.

Please note that students admitted in April 2022 are not eligible for this transfer since they have already paid tuition for the spring semester at the time of enrollment procedures (the transfer will begin in the fall semester). In addition, for students who are adopted by the New Aid System for Higher Education and Enchosei (extended students), the first bank transfer date is scheduled on July 1, in principle.
Please check here for more information on tuition and fees.

Center for English Language Education Faculty Recruitment Information

An international astronomer team has discovered the most distant galaxy candidate to date, named HD1, which is about 13.5 billion light-years away. This discovery implies that bright systems like HD1 existed as early as 300 million years after the Big Bang. This galaxy candidate is one of the targets of the James Webb Space Telescope launched late last year. If observations with the James Webb Space Telescope confirm its exact distance, HD1 will be the most distant galaxy ever recorded.

To understand how and when galaxies formed in the early Universe, astronomers look for distant galaxies. Because of the finite speed of light, it takes time for the light from distant objects to reach Earth. If an object is 1 billion light-years away, it means that the light left that object 1 billion years ago and had to travel for 1 billion years to reach us. Thus studying distant galaxies lets us look back in time.

The current record holder for the most distant galaxy is GN-z11, a galaxy 13.4 billion light-years away discovered by the Hubble Space Telescope. However, this distance is about the limit of Hubble’s detection capabilities.

HD1, a candidate object for the earliest/most-distant galaxy at 13.5 billion light-years away, was discovered from more than 1,200 hours of observation data taken by the Subaru Telescope, VISTA Telescope, UK Infrared Telescope, and Spitzer Space Telescope. “It was very hard work to find HD1 out of more than 700,000 objects,” says Yuichi Harikane, an assistant professor of ICRR, the University of Tokyo, who discovered HD1. “HD1’s red color matched the expected characteristics of a galaxy 13.5 billion light-years away surprisingly well, giving me a little bit of goosebumps when I found it.”

The team conducted follow-up observations using the Atacama Large Millimeter/submillimeter Array (ALMA) to confirm HD1’s distance. Akio Inoue, a professor at Waseda University, who led the ALMA observations, says, “We found a weak signal at the frequency where an oxygen emission line was expected. The significance of the signal is 99.99%. If this signal is real, this is evidence that HD1 exists 13.5 billion light-years away, but we cannot be sure without a significance of 99.9999% or more.”

HD1 is very bright, suggesting that bright objects already existed in the Universe only 300 million years after the Big Bang. HD1 is difficult to explain with current theoretical models of galaxy formation. Observational information on HD1 is limited and its physical properties remain a mystery. It is thought to be a very active star-forming galaxy, but it might be an active black hole. Either possibility makes it a very interesting object. In recognition of its astronomical importance, HD1 was selected as a target for the cycle 1 observations by the James Webb Space Telescope, launched last year. Yuichi Harikane, who is leading these observations, says, “If the spectroscopic observation confirms its exact distance, HD1 will be the most distant galaxy ever recorded, 100 million light-years further away than GN-z11. We are looking forward to seeing the Universe with the James Webb Space Telescope.”

This research will be published in the April 8, 2022 issue of The Astrophysical Journal as Yuichi Harikane, et al. “A Search for H-Dropout Lyman Break Galaxies at z~12-16”. This work was supported by the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT), the Japan Society for the Promotion of Science (17H06130, 19J01222, 20K22358, 21K13953), and the NAOJ ALMA Scientific Research Grant (2020-16B).

Journal: The Astrophysical Journal
Title: “A Search for H-Dropout Lyman Break Galaxies at z~12-16”
Authors: Yuichi Harikane, Akio K. Inoue, Ken Mawatari, Takuya Hashimoto, Satoshi, Yamanaka, Yoshinobu Fudamoto, Hiroshi Matsuo, Yoichi Tamura, Pratika Dayal, L. Y. Aaron Yung, Anne Hutter, Fabio Pacucci, Yuma Sugahara, and Anton M. Koekemoer
DOI：10.3847/1538-4357/ac53a9
URL：https://iopscience.iop.org/article/10.3847/1538-4357/ac53a9
https://ui.adsabs.harvard.edu/abs/2021arXiv211209141H/abstract

New Study Suggests an Alternative Technique for Determining the True Activity of Catalysts

Researchers from Japan perform reliable estimation of the activity of water-splitting catalysts with an unconventional technique

Electrolysis of water into hydrogen and oxygen is a potential source of clean hydrogen fuel. However, the process requires efficient electrocatalysts. Unfortunately, conventional techniques often overestimate their efficiency. Now, researchers from Japan demonstrate an alternative technique for gauging the electrocatalytic performance accurately, opening doors to a smooth transition from lab-scale studies to large-scale hydrogen fuel generation and commercialization of new catalysts with no activity loss issues from overestimation of activity with transient voltammetry techniques.

Electrolysis of water or “water electrosplitting” has received a great deal of attention recently owing to its potential as a clean source of hydrogen, the oft-touted fuel of the future. However, two issues have long stood in the way: the large amount of energy lost, and the cost of electrocatalysts (catalysts used for electrolysis). Fortunately, several new kinds of electrocatalysts have made their appearance, which could potentially solve these issues.

The screening of new electrocatalysts is conventionally performed with techniques such as “linear sweep voltammetry” (LSV) and “cyclic voltammetry” (CV), which involve applying a constantly changing voltage to an electrode and monitoring the resulting current. As this current depends on the rate of oxidation or reduction occurring at the electrode, the measured current readings can be used to determine the effect of an electrocatalyst on the speed of the electrolysis reaction.

However, an obvious drawback of these techniques is that they cannot accurately record the “steady-state” response of the electrocatalyst as it does not experience a particular applied voltage long enough to do so. As a result, substantially high current readings are often recorded, which do not reflect the true catalytic activity, hindering the development of efficient electrocatalysts and promotion of the same to large-scale processes.

In a new study published in the Journal of The Electrochemical Society, Assistant Professor Sengeni Anantharaj from Waseda University, Japan, along with his collaborators Dr. Subrata Kundu from CSIR-Central Electrochemical Research Institute, India, and Prof. Suguru Noda from Waseda University have now found a way around this problem, demonstrating an alternate technique called “sampled current voltammetry” (SCV) as a more reliable indicator of electrocatalytic performance at a constant steady-state applied voltage.

“Screening catalysts accurately is just as important as developing new catalysts for all energy conversion reactions,” says Anantharaj, speaking of his motivation. “Our work has highlighted a way to make accurate measurements of electrocatalytic activity previously not possible with conventional transient techniques.”

Researchers from Waseda University, Japan, suggest an alternate technique for measuring steady-state electrocatalytic activity more reliably over conventional transient techniques, opening up a potential route to efficient hydrogen generation from water splitting.
Photo courtesy: Sengeni Anantharaj from Waseda University

Before applying the SCV technique, the researchers analyzed the errors resulting from LSV. To show the deviation in current values, they used a steady-state technique called “chronoamperometry” (CA), which is the most accurate method of all yet time consuming to measure current at constant voltages and compared it to the values obtained from LSV.

To determine the activity of electrocatalysts used in electrolysis, they measured the current readings of both the oxygen-producing and hydrogen-producing half-cell reactions. Using a stainless-steel (SS) electrode, precipitated Co(OH)₂ (cobalt hydroxide), and platinum foil as catalysts in a KOH (potassium hydroxide) solution, the researchers found that the current density readings from LSV and CA differed significantly, with the difference growing wider at higher applied voltages.

Using the same setup, they then applied the SCV technique and recorded the current densities at various fixed voltages obtained from the steady-state CA responses. “To validate the suitability of SCV, we recorded the CA responses of the SS electrode at various regularly increasing voltages for 130 seconds, within which the SS interface was able to reach a steady state,” elaborates Anantharaj.

From the sampled current readings, the researchers found negligible difference compared to the steady-state CA technique, demonstrating the reliability of the SCV in correctly determining electrocatalyst’s behavior at different voltages. Additionally, while the SCV is particularly useful in the search for a suitable electrocatalyst for water electrosplitting, it can be used to screen electrocatalysts accurately for any electrochemical reaction.

“By addressing the long-standing problem of catalyst performance loss when promoted from the lab to the practical processes, our work could speed up the worldwide adoption of large-scale hydrogen generation from electrolysis,” comments Anantharaj.

It certainly appears we’re now one step closer to the wide adaptation of hydrogen-powered future!

Reference

Authors: Sengeni Anantharaj^1,2, Subrata Kundu³ and Suguru Noda^1,2
Title of original paper: Worrisome Exaggeration of Activity of Electrocatalysts Destined for Steady-State Water Electrolysis by Polarization Curves from Transient Techniques
Journal: Journal of The Electrochemical Society
DOI: 10.1149/1945-7111/ac47ec
Latest Article Publication Date: 5 January 2022
Affiliations:
¹Department of Applied Chemistry, School of Advanced Science and Engineering, Waseda University
²Waseda Research Institute for Science and Engineering, Waseda University
³Electrochemical Process Engineering (ECE) Division, CSIR-Central Electrochemical Research Institute (CECRI), India