Nishizawa Laboratory in Department of Electronics is working on the development of freely-controllable optical frequency comb and its application to innovative environmental spectroscopy measurement technology.

In Nishizawa Laboratory, we are developing new highly functional, freely controllable optical frequency comb light sources with the aim of realizing innovative environmental spectroscopy measurement technology. Recently, we have developed a new ultrashort pulse fiber laser that places a molecular gas cell or a liquid crystal spatial light modulator inside the oscillator, and have succeeded in generating a high level of spectral peaks within the oscillator, and have clarified the physical mechanism behind this.

[1] N. Nishizawa, S. Kitajima, and Y. Sakakibara, "Spectral peaking in an ultrashort-pulse fiber laser oscillator with a molecular gas cell," Optics Letters, vol.47, no.10, pp.2422-2425 (2022).

[2] S. Kitajima, S. Kobata, and N. Nishizawa, “Programmable spectral peak generation by a mode-locked Er-fiber laser with an intracavity LCOS-SLM filter,” Optics Letters, vol.49, no.22, pp.6529-6532 (2024).

The Ohno Laboratory, Department of Electrical Engineering, has developed a new tomography method based on simple measurements.

As part of our research on fusion power generation, which is expected to be a future energy source, we have developed a new measurement and analysis method combining tomography and statistical methods, and clarified the 4-dimensional spatiotemporal behavior of plasma transport phenomenon that is enhanced when the heat load on the device wall is reduced.

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Makihara Laboratory is working on Si-based semiconductor quantum dots, and their process technologies to develop novel functional Si-based devices operating with a few electrons or photons over room temperature

To contribute enhancement of functionality of silicon nanotechnology, we are studying cross-disciplinary research in the rang from materials science to process integration and device technology. In particular, we are developing technologies to control the size and density of Si quantum dots in the self-assembled formation of SiH₄ and GeH₄ gases by LPCVD, as well as developing new functional devices.

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Takeyoshi Kato Laboratory of the Department of Electrical Engineering has been developing a model to promote charging electric vehicles using surplus electricity from renewable energy sources.

Electric vehicles (EVs) can run without CO₂ emission if EVs are charged with surplus power from renewable energy sources. To investigate a required scheme for EVs to contribute a carbon neutrality, we have developed a model for calculating EV charging demand depending on various future scenarios⁽¹⁾. The developed data is utilized for analysis of future supply and demand in various distribution networks⁽²⁾.

The World's first and only: Utilizing light trails, we achieved spatially high-capacity, high-degree-of-freedom parallel transmission in image sensor communication with a few light sources.

An image sensor is a camera's photosensitive device that detects different light sources individually and outputs them as an image. While it can receive many optical signals simultaneously, the transmitter requires many light sources or a large installation area. Controlling numerous light sources with high speed and precision increases design complexity and manufacturing costs. Additionally, fixed light sources limit the density and direction of signal transmission. We proposed the world's first and only parallel transmission method using light trails of moving light sources. This method achieves high-capacity, high-degree-of-freedom parallel transmission with few light sources and a small installation area, enabling multi-directional information transmission. This work has been published in IEEE Photonics Journal and Optics Communications [1][2].

[1] Z. Tang, J. Zheng, T. Yamazato and S. Arai, "Image Sensor Communication via Light Trail Using Propeller LED Transmitter," in IEEE Photonics Journal, vol. 15, no. 5, pp. 1-12, Oct. 2023, Art no. 7304412, doi: 10.1109/JPHOT.2023.3317082.

[2] Z. Tang, T. Yamazato, "Image sensor communication and its transmitting devices," in Optics Communications, vol. 541, 2023, 129545, ISSN 0030-4018, doi: 10.1016/j.optcom.2023.129545.

Uchiyama Research Group in the Department of Electronic Engineering is conducting research on the application of magnetic sensors to medical diagnosis and autonomous driving systems by developing ultra-sensitive, compact magnetic sensors.

We are developing ultra-sensitive compact magnetic sensors using amorphous magnetic wires to measure biomagnetic field associated with electrical activity in the heart and brain in aim of an applications to medical diagnosis. We are also developing a vehicle traffic measurement system for application to autonomous driving.

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Okada research group has been developping wireless communication systems using drones in mountainous areas.

Okada Research Group investigated the feasibility of a self-managed wireless communication system using drones in mountainous areas. In order to provide stable communications between a base station and drones, the location method of wireless relay stations was proposed that takes into account the topography of mountainous areas, and the characteristics of radio propagation in mountainous areas are clarified through experimental measurements.

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Takahashi research group in electrical engineering has been developing new microscopy technology to reveal the functions of cells and materials at nanoscale resolution.

The Takahashi laboratory has been developing scanning probe microscopes based on nanoscale-sharpened glass pipettes to observe the nanoscale structure and function in biological samples and functional materials. In these cell biological applications, dynamically changing such as reagent uptake process can be observed at super resolution. In these material applications, nanoscale geometrical structures and electrochemical information can be visualized, which is useful for the development of highly functional materials.

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The Hayakawa Laboratory has been researching and developing high-voltage technology for vacuum power equipment to reduce global warming gases.

In order to reduce global warming gases in high-voltage power equipment, vacuum interrupters (VI), which perform the current breaking function in vacuum circuit breakers (VCB), are expected to be made with higher voltages. Regarding the voltage application conditions that have been empirically determined in the industrially used method of removing weak points in insulation by discharge between electrodes,i.e. spark conditioning, we have found that it can be optimized by the discharge charge amount from the viewpoint of the melting and adhesion mechanism of the counter electrode material. These results has been published in IEEE Transactions on Dielectrics and Electrical Insulation, vol. 30, no. 6 (2023 Dec.).

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(Tetsu) Iwata laboratory develops quantum attacks against symmetric key cryptosystems.

We develop quantum attacks against symmetric key cryptosystems by using quantum algorithms. The Feistel structure, one of the important structures of block ciphers, is depicted in the left figure. Under the quantum chosen ciphertext setting, the four iterations of the structure can be regarded as a periodic function in the middle figure, allowing an efficient attack with a quantum period-finding algorithm. The right figure shows a pseudorandom function called the Sum of Even-Mansour construction. Although a mathematical proof of security is known in the classical setting, we showed an efficient quantum attack against the construction.

The development of such quantum attacks will be useful in designing symmetric key cryptosystems that are secure against quantum attacks.

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The Tanaka Laboratory has been studying plasma cancer treatments, regenerative medicine, and plasma agriculture using plasma-activated solutions.

In the Tanaka Laboratory, we developed plasma-irradiated solutions (plasma-activated solutions) and we found anti-tumor effects by plasma-activated solutions. In collaboration with Department of Medicine and Agriculture, we are studying the mechanism of action, evaluation of safety and effectiveness, and clinical application research.

A Proof-of-Concept Multi-Band Optical Cross-Connect Node with 300+Tbps Throughput is developed and 2000+km transparent transmission is successfully demonstrated.

As the optical fiber capacity in the C-band is reaching to the theoretical limit, multi-band transmission which adopts the other bands such as S- and/or L- bands is recently attracting attention and extensively studied. However, the introduction of multi-band transmission to transparent optical networks necessiates more complex optical cross-connect nodes which equip switching/amplifying devices dedicated to each band. Therefore, cost-effective implementation of such nodes are hard. We newly developed a multi-band optical node architecture with different routing philosophy. Proposed node firstly groups optical signals in each frequency band and then merges groups of different bands. Then the node swiches the merged signal groups to send to desired outputs. We also developed a proof-of-concept prototype node whose scale is 16x16 and total throughput reaches 300+Tbps. Transmission experiments verify that signals in different bands successfully traversed 2000+km. These results has alreadly been presented at the top-ranked international confernece, Optical Fiber Communication Conference.

A Proof-of-Concept Multi-Band Optical Cross-Connect Node with 300+Tbps Throughput is developed and 2000+km transparent transmission is successfully demonstrated.

As the optical fiber capacity in the C-band is reaching to the theoretical limit, multi-band transmission which adopts the other bands such as S- and/or L- bands is recently attracting attention and extensively studied. However, the introduction of multi-band transmission to transparent optical networks necessiates more complex optical cross-connect nodes which equip switching/amplifying devices dedicated to each band. Therefore, cost-effective implementation of such nodes are hard. We newly developed a multi-band optical node architecture with different routing philosophy. Proposed node firstly groups optical signals in each frequency band and then merges groups of different bands. Then the node swiches the merged signal groups to send to desired outputs. We also developed a proof-of-concept prototype node whose scale is 16x16 and total throughput reaches 300+Tbps. Transmission experiments verify that signals in different bands successfully traversed 2000+km. These results has alreadly been presented at the top-ranked international confernece, Optical Fiber Communication Conference.

In-liquid plasma deposition of nanographene on 3D-structured metal foams

In-liquid plasma process has been an attractive method for nanomaterial synthesis due to its high-yield production in low-temperature atmospheric pressure conditions. This work brings a new perspective on the application through carbon formation directly on three-dimensional metal substrates.

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Yokomizu Laboratory, research group on energy control engineering, has been studying arc quenching materials to achieve higher DC interruption performance of an electric fuse used in an electric vehicle.

Yokomizu laboratory makes a research work on a method for rising the DC interruption performance of an electric fuse installed in the vehicle. The research group has recently focused on addition effect of silicone (C₂H₆SiO) resin to silica-sand (SiO₂ powder) used as the arc quenching medium in the fuse. Experimental verifications show that additive arrangement of silicone resin around a Cu fuse element leads to a twofold increase in the transient arc resistance during the DC interruption process and, as a result, attains reduction in an interruption time of DC1000 A by 20–40% (details are here). The effect achieved by the additive silicone resin is successfully explained, based on the transport property of a mixture of SiO₂/C₂H₆SiO vaporized at high temperatures. This work has been performed in a collaboration with an electric fuse manufacture.

Additionally, the research group also reveals the high-temperature gas properties through quantum chemical theory (details are here). Since last year, the aforementioned works have been made in a collaboration with Iwata Lab., Institute of Materials and System for Sustainability, Nagoya University.

Research on Holographic Display Using Phase Retrieval Method.

Holography is a method for displaying 3D objects using their wavefront information. If the amplitude and phase information of wavefronts can be recorded, we can reproduce 3D objects in the real space. However, the phase information is generally lost at recording. In Fujii laboratory, we propose a holographic display method using phase retrieval, where the missing phase information is recovered from only the corresponding amplitude information.

Optical system (left), previous method (center), and our method (right)

Prof. Kazuo Shiokawa has been reappointed as the President of SCOSTEP.

Prof. Kazuo Shiokawa (Electrical Engineering) was reappointed as the President of SCOSTEP (Scientific Committee on Solar-Terrestrial Physics) at the General Council Meeting of SCOSTEP which was held on July 14, 2023, in Berlin, Germany. The term is for four years from July 2023 to July 2027, in addition to the previous four years. Dr. Bernd Funke of Spain was appointed as the Vice President of SCOSTEP. SCOSTEP is an international organization under the International Science Council and is funded by 34 national and regional scientific councils and space agencies, including the Science Council of Japan. SCOSTEP proposes and promotes international programs on solar-terrestrial physics, including STEP (1990-1994), CAWSES-I, -II (2004-2013), VarSITI (2014-2018), and PRESTO (2020-2024), as well as capacity building activities such as organizing student scholarships and international schools. SCOSTEP is also a permanent observer of the United Nations Committee on the Peaceful Uses of Outer Space.

Analysis of interfacial reaction in all-solid-state lithium secondary battery

All-solid-state lithium secondary batteries are expected to be used for the electric vehicles. Our laboratory has revealed that the activation barrier for the interfacial reactions is lower than that of lithium-ion battery using liquid electrolyte through modeling the graphite negative electrode /solid electrolyte interface.

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High-precision angular distribution measurement technique in semiconductor etching plasma is newly developed

As one of research topics, Toyoda Lab., Department of Electronics, is pursuing analysis of etching plasmas used for semiconductor fabrication processes. In Flash Memory fabrication, high-aspect-ratio (close to 100) hole etching is commonly used and ion directionality control to meet with such high-aspect-ratio etching is required. However, there have been no high-precision measurement technique to evaluate angular distribution of high energy ions impinging on the wafer surface. We have newly developed a unique measurement device to measure angular distribution of impinging ions with using a imaging technique, and have succeeded in measuring ion angular distribution within an error of 0.1 degree, and also succeeded in measuring angular distribution of high-energy neutral atoms. This result will provide vey important information on the guideline for the plasma control and contribute to the improvement of memory performance in the future.

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Typical image of ion and neutral beam measurement

Angular distribution measurements of ion and neutral beams in etching plasma source.

Research on selective doping for p-type gallium nitride utilizing ion-implantation and ultra-high-pressure annealing

To realize the green society, Suda Laboratory has been developing power semiconductor devices, which used in power conversion systems. Gallium nitride (GaN), one of the widegap semiconductors, has attracted much attention as a next-generation semiconductor to reduce the energy loss in power conversion. Selective area doping using ion-implantation is one of the important techniques in the fabrication of power device structures. However, realization of p-type GaN by ion-implantation has been big challenge. We have developed ultra-high-pressure annealing (UHPA) technique, where the high-temperature annealing for implanted GaN is performed under ultra high pressure. Recently, we have revealed that p-type GaN can be formed under the UHPA conditions of 1300°C and 300 MPa, the pressure of which is as low as practical use. This work was presented in International Workshop on Nitride Semiconductors 2022 (IWN2022, Oct. 2022, Berlin, Germany).

(a) Usage of p-type selective doping in vertical power devices. (b) Fabrication process of p-type GaN using ion-implantation and ultra-high-pressure anneal, (c) Temperature dependence of hole concentration and mobility for the GaN measured by Hall-effect measurement. Implanted GaN layers annealed at 1300°C and 300 MPa for 60 min showed p-type conductivity which was equivalent to epitaxially grown p-type GaN layers.

Research on triboelectric energy harvester as a power source for wearable electronics.

Ohno Laboratory is developing soft wearable devices that are in harmony with humans using carbon nanotubes, which have excellent mechanical properties and electrical conductivity. Such wearable devices are expected to be powered using energy harvesting technology, which generates electricity from small amounts of energy in the environment. We developed soft triboelectric nanogenerators that generate electricity from human motion.

Fabricated triboelectric nanogenerator (a) and the generated voltage (b).
The photograph of driving a wristwatch by hand clapping (d,e) by using the intermittent operation circuit (c).

A new display robot for connecting physical space and virtual space was newly developed.

As virtual reality expands, new means of communication are required to connect and integrate physical and virtual spaces.

Kawaguchi Laboratory is developing a new mobile robot called MetaPo that combines a spherical display, a 360-degree camera, an AMR (Autonomous Mobile Robot), and IoT actuators, and is developing a method to connect arbitrary spaces with each other. The first result of this research was presented at the international conference ACM SIGGRAPH held in Vancouver in August.

Details are here

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The developed mobile display robot called MetaPo and the communication using MetaPo.

Research on physical properties of semiconducting materials for realizing next-generation energy devices. (Ikarashi Lab. IMaSS)

Our research interest includes developing next-generation energy device materials for the realizing a sustainable society. For example, introducing impurity atoms into semiconductor crystals and controlling their distribution (doping) are key process for the fabrication of semiconductor devices. Using state-of-the-art analytical equipment at Nagoya University, we are developing technology to measure and control the distribution of impurity atoms and defects in the crystal with atomic resolution.

Behavior Signal Processing Laboratory researches intelligent information processing technology that harmonizes humans and machines.

In our laboratory, we are studying intelligent behavioral signal processing technology for human-environment interaction in the real world, based on machine learning and statistical signal processing. In particular, we tackle problems in automatic driving, human behavior understanding, speech conversion, and human-computer interaction technology required for them. For example, recently, we developed a method to evaluate soccer players who create scoring opportunities for teammates by comparing the reference movements generated by trajectory prediction with actual movements.

Figure: Overview of our method. (i) First, we compute the off-ball evaluation value. (ii) We then predict players’ trajectories. (iii) Finally, we evaluate movements for teammates by the difference between the evaluation value in the actual game situation and the referenced or predicted game situation.

Computer simulations of space plasma processes are performed on supercomputer systems

Space Information Engineering group studies new numerical methods for solving conservation laws in space plasma. Massively-parallel simulation codes are developed based on high-performance computing (HPC) techniques. The computational speed of 1 peta-flops is achieved on the “Flow” supercomputer system Type I at Nagoya University.

(a) Mini-magnetosphere reproduced with supercomputer “K.” (b) Effect of magnetic field on the development of Kelvin-Helmholtz vortices. (c) Supercomputer “Flow” at Nagoya University.

International high-frequency radar network for observing geospace disturbances have been in operation

The Space Observation group has been operating high-radars in Hokkaido, in collaboration with other high-frequency radars operated by more than 10 countries, to monitor electromagnetic disturbances in the ionosphere (90 – 1000 km above the earth) since 2006. This project is referred to as SuperDARN (Super Dual Auroral Radar Network). A lot of scientific results have been obtained from this project.

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(Top) Schematic plots showing the Northern and Southern Hemisphere SuperDARN radar locations with respect to the auroral oval. A typical auroral oval (yellow) is plotted with the SuperDARN radar locations identified in closed circles (Nishitani et al., 2019). (Middle) Schematic illustration of natural phenomena which can be studied by SuperDARN radars (Nishitani et al., 2019). (Bottom) One example of ionospheric plasma flow pattern obtained by the SuperDARN data. The review paper on the accomplishments of the mid-latitude SuperDARN by Nishitani et al., published in PEPS journal in 2019, received a 2021 PEPS most cited paper award.

A real-time spectroscopic system using a fast wavelength switchable terahertz wave parametric generator was newly developed by Kawase laboratory, Department of Electronics.

There is still no practical real-time spectroscopic system using the terahertz wave which is an electromagnetic wave located between radio waves and infrared light. In order to solve this problem, Kawase laboratory has developed a new method to switch the wavelength of an injection seeded terahertz-wave parametric generator (is-TPG) at high speed, and has realized real-time terahertz spectroscopy using up to 17 wavelengths. This achievement has received an award for the best paper presentation at the annual meeting of the Laser Society of Japan and two other workshops.

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(A) Real-time terahertz-wave spectroscopic system with fast wavelength switching (B) Results of fast wavelength switching up to 17 wavelengths and reagents identification

Molecular Dynamics Simulation on Chiral Nano-Needle Fabrication by Opitcal Vortex in Nakamura Lab. (Dept. Electrical Engineering)

Optical vortix is an electromagnetic wave with spiral wavefronts and donut-shaped intensity distributions. Moreover it is expected to be used in new communication modes, material manipulation, and even laser processing. It was reported that the chiral nano-needle structures is fabricated in tantalum by optical vortex laser irradiation. Nakamura Lab. (Dept. Electrical Engineering) has successfully reproduced this chiral nano-needle structure on a computer by modeling the force exerted by the optical vortex on tantalum atoms and calculating the motion of each atom by molecular dynamics simulation. This research was awarded by the Japan Society for Siumlation Technology as the Research Award for 2020.

Molecular Dynamics Simulation on Chiral Nano-Needle Fabrication. The red curve denotes the edge of the nanoneedle.

Sato & Ogawa Laboratory has been developing a text simplification support system.

Sato & Ogawa Laboratory of Department of Information and Communication Engineering has been developing a support system for simplifying Japanese sentences. This system is designed to generate simplified candidates for difficult expressions, implementing four major modules: (1) sentence splitting, (2) simplification of sentence-ending expressions, (3) lexical simplification, and (4) simplified explanation generation of technical terms. For the simplification of sentence-ending expressions, we proposed and implemented a method that combines our language processing tools Panzer/HaoriBricks3 and the neural-based masked language model BERT, and demonstrated that our method outperformed conventional methods by a wide margin.

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Text simplification support system

Pi-phase shift was demonstrated in a nitride-based magnetic Josephson junction by Fujimaki laboratory, Department of Electronics.

In the operation of the superconducting flux quantum bit (qubit), which is an elementary device of the quantum computers, the external magnetic flux bias was required to tune the superconducting phase. This requirement is one of the main issues of the flux qubits toward their large-scale integration. By the developed pi-phase-shift nitride-based magnetic Josephson junction, the flux-bias-free operation of the flux qubits can be achieved leading to the realization of the large-scale quantum circuits. This is a collaborative work with National Institute of Information and Communications Technology (NICT), Japan.

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(Left) Schematics of the pi-phase-shift magnetic Josephson junction and (right) the experimental result to show the pi-phase shift.

Prof. Ando of the Department of Information and Communication presented the study of his new scheme that improves the performance of microprocessors by optimizing instruction scheduling in the issue queue.

The scheme dynamically configures the issue queue as a newly proposed modified circular queue (CIRC-PC) or random queue with an age matrix by responding to the degree of capacity demand. CIRC-PC corrects the issue priority when wrap-around occurs by exploiting the finding that instructions that are wrapped around are latency-tolerant.

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Novel phenomenon of spectral peaking was discovered in Nishizawa Laboratory, Department of Electronics (Quantum Opto-electronics group).

A novel phenomenon of periodical spectral peaking was discovered in Nishizawa laboratory, Department of Electronics. When the ultrashort pulse passed through a molecular gas cell was coupled into optical fibers, the sharp absorption spectra of molecular gas were turned into sharp intense spectral peaks periodically during the propagation along the fiber. This new light source is useful as the novel optical frequency comb, and it can be achieved in wide wavelength range from ultraviolet to mid-infrared. This highly functional light source is expected to apply to the field of optical metrology as the optical frequency standard and ultra-high repetition rate pulse source.

Details are here

Details are here

Spectral peaking with molecular gas and ultrashort pulse

In the Wireless Systems Group of the Department of Information and Communication Engineering, we are studying “Stochastic Resonance” to improve systems' response characteristics by actively utilizing noise.

Stochastic resonance (SR) is a nonlinear phenomenon in which a system's response improves as the noise intensity of the system increases. Traditionally, the noise has been considered a hindrance in engineering and has been actively removed by filtering and other methods. In stochastic resonance, however, a different approach is taken. In other words, the response of a system can be improved by actively using noise. For example, ecosystems have a mechanism that can detect even weak signals buried in noise by skillfully utilizing the noise in signal processing. If we can apply this mechanism to information communication, we can expect to construct an information communication system using weak signals that cannot be detected by conventional systems.

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Transmitted signal waveform and the output signal waveform of the SR system.

Spatiotemporal plasma parameter measurements were succeeded in the detached divertor plasma.

Ohno Lab. (Dept. Electrical Engineering) are working on researches regarding plasma-neutral and plasma-wall interactions to realize the future fusion power generation. In a recent study using a linear device, high temporal resolution parameter measurement was performed with statistical techniques in the detached plasma, which reduces the heat flux flowing into the wall. As a result, spatiotemporal behaviors of electron density, electron temperature, and plasma potential around the plasma ejection event across the magnetic field were revealed.

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(a) Schematic of the measurement system and (b) an example of obtained parameter behaviors.

Energy systems (Chubu Electric Power) funded research division has successfully formed a 3D-printed solid insulator for electrical power equipment.

Solid insulating material group in energy systems (Chubu Electric Power) funded research division has successfully formed a 3D-printed solid insulator for electrical power equipment. A specially-developed 3D printer that minimizes the negative effect on the electrical properties of solid insulators is proposed and constructed. The result is the beginning of the digital fabrication in a power field, which has been presented in CIGRE, the foremost global community for the collaborative development and sharing of power system expertise, and will be published in CIGRE journal. “3D Printed Solid Insulator: Possibilities and Challenges”, M.Kurimoto, Y.Suzuoki, Y.Uchida, CIGRE2020

Behavior Signal Processing Laboratory researches intelligent information processing technology that harmonizes humans and machines.

In our laboratory, we are studying intelligent behavioral signal processing technology for human-environment interaction in the real world, based on machine learning and statistical signal processing. In particular, we tackle problems in automatic driving, human behavior understanding, speech conversion, and human-computer interaction technology required for them. For example, recently, in team sports such as soccer and basketball, we have developed technology that predicts the trajectory of a player by reflecting tactical information and whose information the agents utilize.

Details are here

Figure: Trajectory prediction in (left) soccer and (right) basketball.

Study on plasma medical science

The Hori-Ishikawa Laboratory of the Department of Electronics is engaged in research on the medical application of non-equilibrium atmospheric pressure plasma in collaboration with the Nagoya University Hospital. The recent comprehensive gene expression analysis reveals complex mechanism of the selective killing of cancer cells by plasma-activated solutions. In the future, it is expected to be possible to develop cancer treatment strategies based on personalized medicine by using different plasma active solutions for various cancers with drug resistance.

Details are here

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Yokomizu Lab. (energy control engineering) has developing a small size circuit protection device which enable to interrupt a high voltage and a large fault current.

Our laboratory has been working with Pacific Engineering Corporation on a small DC fuse, aiming to interrupt a large fault current (few thousands ampere) caused in a circuit of EV. We using a polymer material and SiO2 powder as a DC arc extinction medium. Our new method enables the fuse to increase an arc resistance and interrupt the arc in a shorter time. This method can be realized by a change in a chemical composition of the arc and a physical interaction between the arc and the extinction medium.

Details are here

Details are here

Fujii Lab. (Dept. Information and Communication Engineering) has developed a technique of efficiently acquiring 3-D visual information

Fujii Lab. (Dept. Information and Communication Engineering) has developed a technology of efficiently acquiring 3-D visual information. We used a camera where specially-designed code-patterns were inserted at the aperture plane. Our technology enables us to computationally obtain 3-D visual information (as a set of multi-view images) from only two images acquired by this camera. This result was achieved through the joint optimization on the code-patterns and computational algorithm using deep learning.

Details are here

Our neural network models the entire pipeline from capture to computational reconstruction of 3-D visual information

An atmospheric pressure plasma for high-speed large-area treatment is newly developed.

An atmospheric pressure microwave plasma with meter-scale length for large-area high-speed treatment is successfully developed by control of microwave propagation.

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Meter-scale-length atmospheric-pressure microwave plasma

Project of all-solid-state lithium secondary battery

Research and development of innovative rechargeable batteries exceed lithium-ion batteries are indispensable for the commercialization of electric vehicles. Our laboratory participates in NEDO project and conducts research on all-solid-state lithium secondary batteries. In particular, research on graphite negative electrodes for all-solid-state lithium secondary batteries using sulfide-based inorganic solid electrolytes is going.

Realization of a liquid-crystalline structure of magnetic vortices

Magnetic vortices -skyrmions- show the arrays analogous to atomic arrays of solid states. The researchers of Nano-Electronic Materials Laboratory has found a liquid-crystalline structure of skyrmions, using Lorentz transmission electron microscopy. This finding may provide a new avenue for next-generation spintronics devices.

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Research on information security and cryptography

Tetsu Iwata's research group and partners including NEC identified serious security vulnerabilities in the ISO/IEC standard authenticated encryption OCB2. Given the results, ISO/IEC announced the removal of OCB2 from the international standard. The paper describing the vulnerabilities and also proposes ways to fix the issues was presented at CRYPTO 2019, and received the Best Paper award. This work gives useful insight to design secure and efficient authenticated encryption schemes.

Details are here

Overview of the plaintext recovery attack

Announcement of ISO/IEC to remove OCB2 from ISO/IEC19772:2009-02

Establishment of the center for Low-temperature Plasma Sciences (cLPS)

Ceremony, commemorative lectures and facility tour to commemorate the establishment of the center for Low-temperature Plasma Sciences (cLPS) were held on July 23 were held on July 23, 2019. Over 550 participants from universities, reserch institutes, and companies were attended.

High resolution electron microscopy revealed atomic structure of defects in Mg doped GaN.

Atomic resolution structural analysis revealed that Mg impurity atoms (dopant) segregates at defects in GaN crystal and that the segregation determines the upper limits the free carrier density in p-type GaN. The results were reported in the journal, Appl. Phys. Express (vol 12, 031004 (2019)), and the article was selected as a spotlight article (editor-selected article).

This work was completed in collaboration with Toyota Central R&D Labs., Inc. and was supported by MEXT "Program for research and development of next-generation semiconductors to realize an energy-saving society."

High resolution electron micrograph of a Mg segregated defect in GaN. Ga atoms are observed as bright spots. Mg atoms segregate at dark atomic layer sandwiched by GaN crystals. Inset shows simulated image of the Mg segregated defect structure.

Power Electronics Laboratory have achieved 19MHz switching operation using GaN MOS-FET.

Collaboration Project between Power Electronics Laboratory in Nagoya University and TOYODA GOSEI Co., Ltd. has achieved 19MHz switching operation using GaN MOS-FET which is vertical GaN power device. GaN MOS-FET can operate two times higher switching transient as compared with SiC MOS-FET. Using this technique, the wireless power transfer system can expand 10 times power transfer distance in EV, PC and mobile phone applications.

Figure (left) Power Conversion System applying GaN MOS-FET, (right) Comparative data of High Frequency Operation between GaN MOS-FET and SiC MOS-FET

Kazuo Shiokawa (Electrical Engineering) was elected as the SCOSTEP President

During the SCOSTEP General Council Meeting held in July 13, 2019 in Montreal, Canada, Prof. Kazuo Shiokawa (Electrical Engineering) was elected as the SCOSTEP President for the next four years. The SCOSTEP (The Scientific Committee on Solar Terrestrial Physics) is an interdisciplinary body of the International Council for Science (ICSU, currently ISC). SCOSTEP runs international interdisciplinary scientific programs and promotes solar-terrestrial physics research by providing the necessary scientific framework for international collaboration and dissemination of the derived scientific knowledge in collaboration with other ICSU bodies. SCOSTEP is a permanent observer at the United Nations Committee on the Peaceful Uses of Outer Space (UNCOPUOS).

Prof. Kazuo Shiokawa at the inauguration statement.

Behavior Signal Processing Laboratory researches signal processing theory and creates new environment for human.

Behavior Signal Processing Laboratory researches signal processing theory such as machine learning methods, and develops application systems such as speech recognition, behavior understanding, autonomous driving, interaction, sports science and so on. We have realized a multi-modal communication enabled autonomous driving system that can operate the autonomous vehicle using voice, gesture and gaze.

Details are here

Multi-modal Communication Enabled Autonomous Vehicle

Researches on high-density memory and advanced sensor devices

At Iwata Laboratory of Department of Electronics, we have been developing the efficient way of the magnetization switching utilizing spin current, electric field, Joule heating, etc. Functional magneto-resistance sensor devices and nano-fabrication of the magnetic thin films for ultra high-density storage are also studied. These researches are quite important to transform society through the next-generation IoT (internet of Things).

Research of space plasma with the data analysis of satellites and computer simulations

Miyoshi Laboratory (Space Information Engineering group) has studied various phenomena in solar atmosphere and geospace such as solar flares, aurora and high energy electron accelerations using the data from the cutting-edge satellites Arase and Hinode. Moreover, the laboratory has studied space plasma processes with supercomputers.

Caption (a) Geospace exploration satellite “Arase” (© ERG Science Team), (b) Solar satellite “Hinode” (© ISAS/JAXA), (c) The CIDAS supercomputer system at the Institute for Space-Earth Environmental Research.

Development of wearable assistive systems that can contact softly and safely with wearers

Doki Laboratory of Department of Information and Communication Engineering develops wearable assistive systems taking safe and effective assists for wearers. Some prototypes of assistive robot and soft actuators are developed; robots enabling to detect contact force with wearers via tactile pressure sensors for ensuring safety, fabric-type actuators generating three-dimensional motions for assisting human naturals.

pn diodes with GaN theoretical performance limit was demonstrated.

GaN power devices have attracted attention to realize an energy-saving society, but it was difficult to fabricate devices that showed sufficient breakdown voltage. In this research, we developed a fabrication technology of a Butte type structure that deeply and vertically etched GaN. By using this method, we succeeded in fabricating GaN vertical pn diodes with uniform electric field distribution and the breakdown voltage of the theoretical performance limit.

Details are here

(a) Schematic image of the Bute type GaN pn diode, (b) Cross sectionnal SEM image, (c), (d) Simulation result of electric field distribution, (e) Emission image by avalanche breakdown current, (f) Reverse direction J- Etching depth dependence of V characteristics

New longitudinal network observatories, which measure aurora and electromagnetic waves from geospace, have been developed

The Space Observation group has been installed high-sensitive cameras, magnetometers, and antennas at Russia, Canada, Alaska, Iceland, and Finland to monitor longitudinal extent of aurora and radio waves from geospace since 2016, in collaboration with the Arase satellite of JAXA. This project is named as PWING Project. A lot of scientific results have been obtained from this project.

Details are here

(Left) Observation sites of the PWING Project. The Pc1/EMIC waves were observed over 200-deg longitudes at the arrival of specific solar-wind structure called CIR on March 21, 2017. (top right) Interesting blue aurora was observed at that time at Husafell, Iceland (Shiokawa et al., GRL, 2018). (bottom right) Longitudinal distribution of oxygen ions in geospace around the earth (Nosé et al., GRL, 2018).

This work is supported by JSPS KAKENHI (JP 16H06286; 16H04057).

Early Detection of Symptoms of Dementia is challenged by measuring EEG (Electroencephalogram).

Furuhashi laboratory identified the model to estimate MMSE (Mini Mental State Examination) score using EEG data measured by a smart chair* equipped with non-contact magnetic sensor. It is expected that the possibility of dementia can be detected at an early stage while an elderly person living alone is relaxing with a smart chair every day.

*Under development in Sustainable Platform Research Group of Nagoya university COI (Center of Innovation)

Details are here

Details are here

Real-time Terahertz spectroscopy and fast spectroscopic imaging system using multi-wavelength terahertz parametric generation were newly developed.

Real-time terahertz spectroscopy and fast spectroscopic imaging system were succeeded using multi-wavelength terahertz parametric generation and detection technique. It can be used for illicit drug detection in a mail and nondestructive testing of the plastic product.

Details are here

Details are here

We have succeeded in the real-time terahertz spectroscopy and fast spectroscopic imaging system using multi-wavelength terahertz parametric generation and detection technique.

DNA damage by tritium disintegration was estimated qualitatively, using molecular dynamics simulation.

We estimate the DNA damage by disintegration of tritium to helium (beta decay) qualitatively using Molecular Dynamics (MD) simulation. In the simulation, we adopted telomere structure of the human DNA. Moreover, we replaced some hydrogen atoms in guanine of the telomere to helium atoms. Then we perfumed MD simulation and analyzed the DNA structure. From this simulation, we found that as the number of the replaced helium increases, the double helix structure of the telomere becomes more fragile.

Fig : As the initial configuration, some hydrogen atoms in guanine of the telomere are replaced to helium atoms (Gray balls). We performed MD simulation, and it is found that this replacement weakens the hydrogen bonding between DNA chains.

The book of Todai Robot Project was published from University of Tokyo Press

Sato-Matsuzaki Laboratory has conducted research on automatic solving university-entrance exam from 2013, as a member of Todai Robot Project. Our research results in three subjects, Japanese Language, Mathematics, and World History, are described in this book.

Details are here

Execution of Stored Programs in a Superconductor Single-Flux-Quantum Microprocessor with Embedded Memories was demonstrated at 50 GHz

We successfully executed programs stored in an instruction memory in a superconductor single-flux-quantum bit-serial, 8-bit microprocessor using 50 GHz clocks. This is the first demonstration of stored-program computing using non-semiconductor integrated circuits.

Details arehere

Details arehere

Microphotograph of demonstrated microprocessor (Fabricated with the AIST process.)

The highest superconducting property at liquid nitrogen temperature was achieved by introduction of well-aligned artificial pinning centers into high temperature superconducting films.

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(a) plan-view and (b) cross-sectional transmission electron microscopy in RE-based high temperature superconducting films with well-aligned artificial pinning centers.

Success of non-destructive deep imaging of mouse brain using 1.7 um OCT/OCM

Researcher in Nishizawa lab. in Dept. Electronics developed high resolution optical coherence tomography (OCT) / optical coherence microscopy (OCM) using wideband ultrashort pulse fiber laser source at 1.7 um for the first time. Using the developed system, they succeeded in the non-destructive measurement of deep part of mouse brain (hippocampus) with micrometer resolution.

Details are here

Details are here

Large-scale fuzzy metallic nanostructure processing method was newly developed.

Large-scale fiberform nanostructures can be developed on metal surfaces by additional precipitation of metallic particles together with He ion bombardment in plasmas.

Details are here

Fig : A scanning electron microscope micrograph of a part of large-scale fuzzy structure.

Toward the realization of reliable remote machine control: Cross-layer optimization of control and communication

Katayama Laboratory (Institute of Materials and Systems for Sustainability) of Department of Information and Communication Engineering has been conducting research in communication systems for reliable remote machine control, and has proposed cross-layer optimization schemes that achieve not only communication performance improvement but also control performance improvement as an entire system. We are working for further developments of this work partly supported by JSPS Grant-in-Aid for Young Scientists (B) under Grant 15K21071.

Details are listed below (Papers)

• http://hdl.handle.net/2237/27527
• http://hdl.handle.net/2237/26839
• http://hdl.handle.net/2237/26841

Details are listed below (International Conferences)

• https://dx.doi.org/10.1109/SPAWC.2017.8227784
• https://dx.doi.org/10.1109/ISPLC.2017.7897109
• https://dx.doi.org/10.1109/WCNC.2017.7925905
• https://dx.doi.org/10.1109/WCNC.2017.7925825

JOB OPENING (deadline of application: 29 June 2018)

Applications are invited for a Professor at Department of Electronics Engineering, Graduate School of Engineering, Nagoya University.

Details are here

Toward gas-insulated power apparatus for the next generation with functionally graded materials

Hayakawa Laboratory at the Department of Electrical Engineering has proposed to apply functionally graded materials (FGM) to the compact and advanced gas insulated power apparatus for next generation. Recently, we presented 2 papers on its effect of electric field relaxation and breakdown strength improvement at the international conferences, ISH2017 on high voltage engineering and CEIDP on electrical insulating materials. This research is on-going as a project commissioned by the New Energy and Industrial Technology Development Organization (NEDO) which was approved and started this year.

Details are here

Fig : Fabrication of permittivity graded material (ε-FGM) for gas-insulated switchgear spacers

Formulated Representation for Upper Limitation of Deliverable Power in Low-Voltage DC Distribution System

The research group on electrical-energy conversion engineering (Prof. Y. Yokomizu) has derived the formulated representation for the upper limitation of a deliverable power in a direct-current distribution system, in view of the voltage-instability phenomenon occurring at a load terminal.
This achievement reveals one of the significant properties for the dc delivery system, supporting employment of the direct current delivery in various electric facilities.

Details are here

JOB OPENING (deadline of application: 30 September 2017)

Applications are invited for an Assistant Professor at Department of Electronics Engineering, Graduate School of Engineering, Nagoya University.

Details are here

JOB OPENING (deadline of application: 30 September 2017)

Applications are invited for an Assistant Professor at Research Group of Electrical Energy Conversion, Department of Electrical Engineering, Graduate School of Engineering, Nagoya University.

Details are here

JOB OPENING (deadline of application: 30 September 2017)

Applications are invited for an Associate Professor or Lecturer at Department of Electronics Engineering, Graduate School of Engineering, Nagoya University.

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We have developed a system that can display real 3-D objects on a layered 3-D display.

Visual Information Laboratory of Department of Information and Communication Engineering has developed an end-to-end system where images of real objects are taken from 25 different viewpoints, converted into a layer representation, and fed to their prototype 3-D display that is composed of three stacked LCD panels.
Their system provides not only binocular 3-D perception but also natural motion parallax along with the motion of the observer.

Details are here

Fig : Process Pipeline of 3-D Display System

Oxide Film Deposition by Magnet-free Sputtering Using Surface Wave Plasma

Plasma Electronics research group developed a magnet-free sputtering device by combining a surface wave plasma and RF bias power.
The efficiency of utilizing a sputtering target was improved as compared with the conventional magnetron sputtering and deposition of high-quality insulating film with good spatial uniformity was realized.
The technique is expected to be applied to next-generation MRAM manufacture.

Details are here

Fig : Magnet-free sputtering device using surface wave plasma with RF bias power

JOB OPENING (deadline of application: 30 September 2017)

Applications are invited for an Assistant Professor at Department of Electronics Engineering, Graduate School of Engineering, Nagoya University.

Details are here

JOB OPENING (deadline of application: 30 September 2017)

Applications are invited for an Assistant Professor at Research Group of Electrical Energy Conversion, Department of Electrical Engineering, Graduate School of Engineering, Nagoya University.

Details are here

JOB OPENING (deadline of application: 30 June 2017)

Applications are invited for an Associate Professor at Department of Electronics Engineering, Graduate School of Engineering, Nagoya University.

Details are here

JOB OPENING (deadline of application: 31 May 2017)

Applications are invited for an Assistant Professor at Department of Electronics Engineering, Graduate School of Engineering, Nagoya University.

Details are here

JOB OPENING (deadline of application: 30 June 2017)

Applications are invited for a Professor at Department of Electrical Engineering, Graduate School of Engineering, Nagoya University.

Details are here