Hokkaido University Research Profiles

Japanese

9. Industry, Innovation and Infrastructure: 102

Numbers of lines 20 50 No Page Break Theme Icons
  • 1. No Poverty
  • 2. Zero Hunger
  • 3. Good Health and Well-being
  • 4. Quality Education
  • 5. Gender Equality
  • 6. Clean Water and Sanitation
  • 7. Affordable and Clean Energy
  • 8. Decent Work and Economic Growth
  • 9. Industry, Innovation and Infrastructure
  • 10. Reduced Inequality
  • 11. Sustainable Cities and Communities
  • 12. Responsible Consumption and Production
  • 13. Climate Action
  • 14. Life Below Water
  • 15. Life on Land
  • 16. Peace and Justice Strong Institutions
  • 17. Partnerships to achieve the Goal
  • Equipment for Simultaneous Optimization of Quality and Quantity of Liquid Ice for Freshness Preservation

    Liquid ice optimization system for long-term freshness preservation of food

    We have developed a device that calculates the minimum required amount of food-grade liquid ice (slurry ice (salt water ice) or salt-free water ice) using a simple heat capacity calculation, and that also calculates the salt concentration, water/ice mixing ratio, and shelf life to determine the slurry ice temperature based on the overall heat transfer coefficient (container heat radiation parameter) of the storage container.

    Research

    The amount of produced slurry ice, which is useful for maintaining the freshness of marine animals, often exceeded the amount actually used because there was not a calculation method that took storage time into account. At our laboratory, we have developed a device to optimize the quality (salt concentration and water/ice mixing ratio) and quantity (shelf life) of slurry ice simultaneously and quickly on the spot based on the overall heat transfer coefficient of the storage container, as described earlier. Since this method can be applied to the production of fresh water-derived salt-free liquid ice, it can also be used for other food than marine animals (vegetables, fruits, and livestock), and we are currently working to obtain the rights to this invention.

  • MIRASAL, a Device for Visualizing the Freshness of and Best Timing for Eating Food Animals

    A device for evaluating the freshness of and the best timing for eating food animals to ensure safety and security

    In collaboration with the National Institute of Advanced Industrial Science and Technology (AIST), we have developed a visualization device called MIRASAL to evaluate the freshness of and the best timing for eating food animals by using a simulation method to determine the concentration of degraded components in any part of a food animal (aquatic or livestock animal), which changes over the course of time after the animal has died.

    Research

    At the wholesale markets in fish and shellfish production and consumption areas, freshness is an important criterion in the determination of transaction prices, and the K value has been proposed as an evaluation index. However, since the K-value is calculated by sampling any part of a postmortem marine animal and analyzing the components after various pretreatments, real-time evaluation (understanding) at the distribution site is not possible. Aiming to solve this problem using an appropriate simulation method, we have developed a device that can evaluate the freshness and the best timing to eat fish and shellfish based on various information such as the type and size of the fish and shellfish, the elapsed time since death, and the storage temperature, using the method described above. We are currently working on the acquisition of the rights to the invention and for improvement of its portability (for use with smartphones, etc.). This device “MIRASAL” can also be applied to livestock animals such as beef, chicken, and pork.

  • A Novel Porous Structure with High Mechanical Performance for Additive Manufacturing

    Biomimetic design based on bone biomechanics

    A novel three-dimensional (3D) printed porous structure with high mechanical performance is designed biomimetically based on the insights of bone biomechanics. The resulting structure might be lightweight and mechanically isotropic with suppressed fracture progression and high energy absorption.

    Research

    In general, porous structures with repeating units, such as diamond lattices, suffer from mechanical issues, such as fracture development, low energy absorption, and mechanical anisotropy due to these repeating units. To address these issues, we develop a novel porous structure with high mechanical performance for additive manufacturing. The structure is designed biomimetically based on the insights of bone biomechanics. It has a framework made up of 3D isotropically interconnected beams. Here, the beam lengths and bifurcation counts are arbitrarily determined using probability distributions without any repeated units. Furthermore, the structure can be manufactured through the powder bed fusion of a laser beam using metal powders and material extrusion using plastic filaments. Additionally, compression tests revealed that the structure exhibited suppressed fracture progress after the initial fracture and increased energy absorption. Moreover, the fracture behavior of the structure was found to be independent of the compression direction because of its structural isotropy.

    Satoshi Yamada Assistant Professor
    PhD
    Division of Mechanical and Aerospace Engineering, Faculty of Engineering
  • Metabolism of Biological Components and Pre-symptomatic Disorder

    Elucidation of the mechanism of non-infectious pathogenesis by considering the metabolism of biological components: Application as a system of evaluating the functionality of foods

    Based on the metabolic analysis of biological components (bile acids, minerals, etc.), we conduct research on the elucidation of the pathogenesis of various diseases and the establishment of pre-symptomatic disorder models using laboratory animals. We aim to elucidate the point of action in prevention of disease onset via dietary intervention.

    Research

    The composition of bile acids synthesized by the liver fluctuates with aging and excessive energy intake, and that can be estimated under these conditions. Therefore, by feeding a very small amount of a specific bile acids to experimental animals, it is possible to create a state that mimics the bile acid environment in the corresponding situation. We have found that this results in fatty liver and related pathologies. We also found that a mild deficiency of zinc is a pre-symptomatic disorder model for ulcerative colitis. These findings indicate that minor metabolic changes that occur continuously due to dietary bias (excess or deficiency) are involved in the onset of infectious and non-infectious diseases, and that the experimental system itself, which mimics the situation by controlling dietary components, can serve as a model of pre-symptomatic disorders. Currently, we are constructing various pre-symptomatic disorder models and analyze their pathogenic mechanisms. We are also using these systems to evaluate the functionality of foods.

  • Ecosystem Restoration of Disturbed Areas

    Promoting eco-friendly restoration of ecosystems that have been disturbed by natural or human activities through facilitation.

    Facilitation refers to a phenomenon whereby the establishment of a certain plant prompts the invasion and establishment of another species. In ecosystems that have suffered catastrophic damage due to a major disturbance such as a volcanic eruption, fire, tsunami or mining, the detection and introduction of such facilitators will help rapid and eco-friendly ecosystem restoration.

    • Fig. Platanthera metabifolia, which has taken root in a patch of Mineyanagi willow on Mt. Komagatake in Oshima after its major eruption in 1920.
      The Mineyanagi willow promotes the colonization by many species and thereby enhances ecological diversity .

    • Fig. Relationship between coverage of M. sinensis, a facilitator, and the number/density of woody plants on a ski slope in Sapporo (plot size: 4 m2).
      The colonization of M. sinensis prompts an increase in the number of woody plants, so the creation of M. sinensis grasslands will lead to the growth of natural forests without afforestation efforts.

    Research

    Ecosystem restoration after large-scale disturbance is often an urgent task, but it has often been difficult to establish a target plant species in a disturbed environment. A facilitator is a plant species that prompts the establishment of other species once it has been established. If we can detect and establish a facilitator in the respective disturbed areas to prompt the invasion and establishment of the target species there, it will be possible to quickly restore ecosystems in a cost-effective manner with minimal human effort. Therefore, this is an ecofriendly technology for ecosystem restoration.
    So far, we have found that the white beak-sedge (Rhynchospora) is functioning as a facilitator in the post-mined peatland of Sarobetsu Mire, and the Mineyanagi willow in Mt. Komagatake in Oshima, Hokkaido. Microtopography modification has also been found effective as a means of introducing facilitators.

  • Nano Knowledge Exploration Project

    Knowledge discovery from experimental records of nanocrystalline devices

    In this research, we are studying knowledge management to extract and organize useful information for device development from experimental records and papers compiled in the process of research and development of nanocrystal devices.

    Research

    In this presentation, we propose an experiment record management system based on interviews with researchers in actual nanocrystal device development. The system proposes an integrated method for the management of records of parameters used in experiments that have been stored and recorded separately, as well as the resulting experimental records. In addition, by extracting information from the paper summarizing the final experiment, we propose a method for analyzing the purpose and characteristics of a series of experiments conducted by researchers in detail, and for using it as the basis for discussing similarities between various cases. With this method, we are proposing a method of extracting useful information from unknown papers by using machine learning methods on a corpus of information manually extracted by a few people.

  • A method to evaluate radio wave propagation characteristics of in-vehicle wireless access services by large-scale electromagnetic field analysis

    Toward optimal design of wireless environments

    We have conducted research in various fields where radio waves are applied, including the evaluation of complex and special propagation environments in airplanes and passenger railroad cars, internal exposure of the human body to radio waves, electromagnetic interference evaluation and mechanism estimation regarding body medical devices implanted in the body, and evaluation of electromagnetic field leakage in wireless power supply devices for electric vehicles.

    Research

    The radio propagation environment inside a vehicle is a special environment that differs from the conventional propagation model due to multiple reflections caused by the surrounding metal and the presence of fixtures and passengers inside. It is therefore necessary to evaluate the characteristics of radio wave propagation, including the effects of absorption and scattering of radio waves by the bodies of passengers, to estimate the quality of the wireless connection under actual operational conditions. However, it is difficult to evaluate the propagation characteristics by actual measurement or simple numerical analysis (e.g., ray tracing). This study addresses modeling of the propagation environment in vehicles, which has been difficult in the past, and realizes a simulation method in a very large analysis space by using a supercomputer.

  • A Study on Pro-beam Roadway Lighting in Urban Areas

    To prevent night-time accidents involving pedestrians at intersections in urban areas, we are developing a Pro-beam road lighting system that works with headlights to help drivers quickly detect pedestrians crossing the street. Pro-beam is a lighting system whereby the light distribution of the lamps is directed in the travelling direction of the vehicles.

    Research

    We have summarized the requirements and functions of pro-beam road lighting to design specific light distribution of Pro-beam lighting to increase the visibility of pedestrians crossing the road through optical simulation and visibility evaluation experiments. Using the prototype light fixture, we have evaluated drivers’ visibility of pedestrians who are standing still and measured the time until drivers detect pedestrians at intersections using video images. As a result, we have confirmed that the Pro-beam lighting system provides higher visibility of the entire road space, including the oncoming lane, and helps drivers quickly detect pedestrians crossing the road not only from the right but also from the left. We are now working on the design and development of a light fixture for practical use as a road light by developing the prototype light fixture.

  • Academic Intercloud

    Promoting research and development through academic cloud collaboration

    We promote research to create an academic intercloud that links nationwide cloud systems, and conduct joint research on cloud-related technologies such as the optimization of resource allocation in intercloud environments and linkage between supercomputers and interclouds.

    Research

    Hokkaido University Information Initiative Center has established the Hokkaido University Academic Cloud, one of the largest academic clouds in Japan, and provides cloud services to researchers nationwide, including those concerning virtual and physical machines and their cluster systems, high-speed high-capacity cloud storage services, and machine learning and big data processing systems for research and development. We are also promoting research on fundamental technologies to realize nationwide cloud system collaboration and system construction to support researchers. Specific examples include the development of infrastructure technologies for cloud collaboration (authentication collaboration, etc.) and the construction of a test system (Fig. 1), resource allocation optimization in an intercloud environment, and the realization of a large-scale design optimization framework on a nationwide scale by linking supercomputers and intercloud infrastructure (Fig. 2). We are also conducting joint research with universities, research institutes and companies across the country.

  • Advanced Optical Communication Technology, the Core of the Next-generation Ultrahigh-speed Communication Network

    Aiming at spectacular advancement of information and communication networks

    To realize spectacular advancement of information and communication networks of which the capacity has to increase by a factor of 1,000 in the next 20 years, we are working to develop photonic infrastructure technology that will be the core of next-generation ultrahigh-speed communication networks.

    Research

    We are studying new structured optical fibers to overcome the limitation of existing optical fibers, optical fiber application technologies to ensure safety and security, ultra-compact optical circuits to support opticalization, and optical simulators to support the design of optical fibers and optical circuits.

  • Alpha-defensins Prompting a Paradigm Shift in the Intestinal Environment

    From a scientific understanding of ishoku-dougen (an idea that the same principles underlie a normal diet and medical treatment) to preventive medicine

    The α-defensins secreted by Paneth cells regulate the intestinal microflora and are deeply involved in their elimination and symbiosis. We will evaluate the intestinal environment from the viewpoint that the intestinal environment is defined by the three elements of food, α-defensins and intestinal bacteria, and create a paradigm shift to contribute to the clarification of disease mechanisms and the development of preventive medicine.

    Research

    Using isolated small intestinal crypts and enteroids, which are three-dimensional small intestinal epithelial culture systems, we will elucidate the innate immunity of Paneth cells, which are intestinal epithelial cells (that secreteα-defensins), symbiosis with intestinal bacteria, regeneration and differentiation and other molecular mechanisms associated with various functions, taking advantage of state-of-the-art analytical methods such as confocal laser microscopy and flow cytometry. The intestine forms a network between various organs in the body and by analyzing the mechanism of the intestinal environment focused on the function of Paneth cells will make it possible to control the intestinal environment and create preventive measures and treatments for various diseases. From the perspective of the intestines, “food” and “drugs” virtually mean the same thing. We hope to contribute to the realization of a healthy longevity society through industry-academia-community collaboration based on the knowledge we have created.

  • An Idea-supporting Multimedia Search System

    An information retrieval system that organically links images, video and other data to help searchers find inspiration and ideas.

    The idea-supporting multimedia search system organically links unstructured data such as images, music and video, extracts inherent similarities and effectively presents them to searchers to help them find ideas and inspiration.

    Research

    We have succeeded in establishing associations and similarities between different media, and developed an associative search scheme that takes ambiguity of multimedia information into consideration (fused search). We have also realized a new search engine and interface by quickly introducing modeling of personal preferences through user networks and visualization of similarities in preferences through user interfaces (personal adaptive search). Use of the search engine and interface enables a completely new search that effectively utilizes the polysemy and ambiguity inherent in multimedia contents.

  • Analysis of Thermo-acoustic Vibration Generated by Combustion Equipment

    Thermo-acoustic vibrations often occur in combustion devices and combustion gas exhaust systems, causing noise and reducing the life of the combustion devices. This is caused by acoustic pressure fluctuations coupled with heat generation fluctuations in combustion and exhaust systems. With this study, we analyze this physical process and investigate the suppression technology.

    Research

    Thermo-acoustic vibrations are often generated in combustion equipment and combustion gas exhaust systems, leading to noise generation and reduction of the life of combustion equipment. This is caused by acoustic pressure fluctuations linked to heat generation fluctuations in the combustion and exhaust systems, and we are analyzing the physical processes that cause these fluctuations and investigating techniques to suppress them. With this study, a single circular tube is filled with a combustible premixed gas that is ignited at one end, and a thermo-acoustic vibration phenomenon that occurs during flame propagation in the tube is used. Various boundary conditions (open end condition, direction of propagation, composition of the gas mixture, diameter and length of the propagating tube, structure of the flame surface, etc.) are applied to this propagation phenomenon to induce the thermo-acoustic vibration phenomenon, and the factors behind it can then be understood using the combustion instability analysis method. The vibration phenomena reproduced here are observed in a simplified system, but they are general phenomena and lead directly to the understanding of thermo-acoustic vibration phenomena that occur in actual combustion equipment and exhaust systems.

  • AR Communication System

    Avatar-based augmented reality group communication through sharing of terminal position and posture information

    By using avatars as intermediaries, it is possible to communicate beyond the constraints of time and space. In this system, AR communication is realized by sharing the position and posture information of participants in group communication and reflecting it in the behavior of avatars visible from each participant's terminal.

    Research

    Since conventional avatar-based communication systems are based on one-to-one communication, it is difficult to recognize the position and posture information of each physical person participating in a communication field of three or more people where virtual and real worlds are mixed, and to control the behavior of individual avatars accordingly, while maintaining the integrity of the entire field.
    In this research, we have developed an AR communication system that shares the position and posture information of physical people (e.g., smartphone terminals) participating in a communication field through recognition of a common AR target and network linkage between terminals, and reflects this information in the behavior of avatars visible from each terminal. The avatars know who and where the participants are in the communication field, and the avatar changing its pose following the movements on one participant's terminal can be seen by other participants from their own viewpoints.

  • Boundary Element Analysis Framework and Distributed H-matrix Method

    Realizing cutting-edge, large-scale, high-precision analysis

    We have developed a software framework for high-performance boundary element analysis in a parallel computing environment. We have also developed a distributed parallel H-matrix library, which is effective to accelerate a BEM analysis, and evaluated its performance on programs in various applications.

    Research

    In this study, we developed a parallel boundary element analysis framework as part of the JST CREST project on “Application Development and Execution Environment with Automatic Tuning Mechanism.” By using this framework, it is possible to develop boundary element analysis programs for large-scale parallel computing systems with a small programming cost. We also developed a library of H-matrices, which approximates dense matrices with less data using low-rank approximation. This library can be used for analysis of N-body problems in addition to boundary element analysis, and is already being used for earthquake simulation on supercomputers. There is no other H-matrix library that supports hybrid parallel processing utilizing multiple threads and processes, and this is a unique feature of this research.

    Takeshi Iwashita Professor
  • Clarifying the Physical Constants of Electron Spin Control

    Accelerating the research and development of next-generation electronic devices

    Among various semiconductor properties, we have quantitatively clarified the previously unknown “spin-orbit interactions” of n-type quantum well structures based on InGaAs semiconductors, including gate voltage dependence. This achievement will be a seed for the development of next-generation spin devices.

    Research

    Existing semiconductor devices operate through the electric charge of electrons. In addition to the electric charge, an electron also has the other property of spin, which is a magnetic property. The electron spin in a solid can be aligned in a certain direction (Fig. 1a) or rotated about a specific axis (Fig. 1bc), depending on the situation. The key to realizing next-generation electronic devices is to control such electron spin in semiconductor devices. In this study, we used indium-, gallium-, and arsenic-based field-effect transistors (Fig. 2) and performed electrical measurements in a cryogenic environment (absolute temperature of 20 mK) using a dilution refrigerator (Fig. 3). In this way, we were able to precisely determine for the first time the spin-orbit interaction coefficient, which is necessary to control electron spin (Fig. 4).

  • Classification of Genetic Information Using Machine Learning

    Predicting the binding of compounds to cell receptors

    Various receptors on the surface of cells play important roles in maintaining homeostasis and environmental responses, but it is difficult to identify compounds that can bind to them. We propose a method for narrowing down the candidates for binding compounds by using machine learning.

    Research

    Although the human genome has been deciphered and many of the genes have been elucidated, the structure and function of receptors, which play an important role in homeostasis and environmental responses, have not been fully elucidated, because most of them are membrane proteins and their expression levels are low. Many receptors, however, are expected to be major targets for drug discovery in the future because of their functional aspects, and are thought to be the factors that cause individual differences. We are applying machine learning technology to efficiently narrow down compounds that can bind to receptors.

  • Coherent Raman Scattering Endoscope

    Development of an eye for a novel endoscopic surgical support robot using coherent Raman scattering for label-free nerve visualization

    Raman scattering provides insight into molecular species and structures without staining, but its use has been limited due to its extremely weak scattering. We are developing microscopes and endoscopes that provide Raman images in real-time by using coherent Raman scattering phenomena with ultrafast lasers.

    Research

    Raman scattering has been used in chemical analysis, physical chemistry, and semiconductor research because it provides information on molecular species and structures without staining. It is also recently actively applied to the biological and medical fields. However, Raman scattering is very weak. We have developed a multifocal coherent Raman scattering microscope with integrated a wavelength-tunable synchronous picosecond laser and realized imaging at 100 frame/s, which is faster than the video rate. We also demonstrated that nerves are visualized without staining and at high speed under a rigid endoscope of 12 mm in diameter and 550 mm in length. It is expected to be a new imaging tool for nerve-sparing endoscopic surgery.

  • Communication Robot System

    Social space recognition system using dialogue activity and attention guidance system and multiple robots

    By calculating the level of activity of a dialogue between people, a robot can recognize the intensity of that dialogue space and adapt its behavior to the context. Furthermore, by applying this mechanism to the behavior of multiple robots, it will become possible to guide the user's attention.

    Research

    Our dialogue activity calculation system calculates the real-time activity level using information such as the distance between the interactants, voice data, and body movements. By using this activity level, the robot can determine whether it is allowed to enter the dialogue space or interrupt the dialogue, and can take contextually adaptive actions. Furthermore, by having multiple robots act in a way that increases the dialogue activity level for each other's actions, the user's attention (e.g., gaze) can easily be guided. Such a system for generating robot behavior using the level of dialogue activity has not been included in conventional research on social robots, and can be applied to robots at reception desks and home robots for households.

  • Control of Sedimentation and Diffusion Behavior Using the Collectivity of Particles in Liquid

    Free control of the settling behavior of particles

    We introduce technologies to accelerate the sedimentation rate and control the dispersion behavior of particles in complex channels by taking advantage of the collective nature of particles observed when there is a difference in the concentration of the suspension.

    Research

    We propose technologies to actively control the sedimentation rate and dispersion behavior by effectively using the collective nature of particles in liquid caused by concentration differences. When suspension conditions change, heterogeneously dispersed particles show collective sedimentation behavior. We aim to understand the behavior of particles near the concentration interface, which is closely associated with such collective behavior, to actively use it to promote sedimentation, control dispersion and improve transport efficiency, all of which are important in various engineering processes.

  • Cooperation and Value Creation in Community-based Workspaces

    Development process of coworking

    In recent years, working systems of individuals who do not necessarily have the same occupation or affiliation but interact and cooperate with each other according to the situation in organizations and local communities, as well as the workplaces that they share, have been attracting attention. This research is aimed to clarify the process of cooperation and value creation in such workplaces.

    Research

    The purpose of this study is to elucidate the process of cooperation and value creation in a community-type workspace. A community-type workspace is an open workspace where individuals share information and knowledge with other through communication, and create value through collaboration according to the situation. A coworking space is a typical example of such a place, and in recent years, it has been becoming more and more popular in Europe, the U.S., and the rest of the world. In the background, there is a movement of questioning the highly uniform interaction and cooperation among members in closed spaces, a system that is still dominant in organizations and local communities, and to achieve both individual autonomy and solidarity. This research is expected to provide knowledge that will contribute to the design and operation of such workspaces, as well as their organizational and social utilization, which are still largely unknown.

  • Creating Appropriate Governance Systems based on Theory and Practice

    Making Our Society Safer and More Secure through Public-Private Collaborations

    Based on my previous case studies on safety and environmental regulatory processes, science and technology policies, and regional developments, I conduct research on how to create appropriate governance systems that contribute to solving public policy problems in introducing and disseminating advanced technologies into society. Governance theory and practice, through collaboration with stakeholders, will undoubtedly help.

    Research

    While technology greatly benefits society, it also poses various risks. Therefore, when introducing advanced technology, it is necessary to design governance systems that minimise these risks and to determine the optimal public policies to maximize the benefits.
    In the case of automobiles, the perception of the regulatory policy often differs among stakeholders such as manufacturers, regulators, and users. Regulatory policy is also largely determined by harmonized international standards.
    As such, I define public policy problems in introducing advanced technology into society based on an understanding of the overall picture, seek a place in which stakeholders can reach an agreement, build consensus, and consider how to create governance systems in which the public and private sectors can cooperate.

    Yuichi Murakami Associate Professor
    Ph.D.
  • Creation of Highly Active Catalysts Using Polystyrene-bridged Bisphosphine Ligands

    Design of metal complex catalysts using polymeric carriers as the reaction site and development of an efficient synthetic processes

    We have developed polystyrene-crosslinked bisphosphine ligands that can be used to create polymer-supported metal catalysts. Thanks to the effect of polymer topology, it is possible to suppress disproportionation of metal complexes and deactivation of catalysts caused by metal aggregation. It is particularly useful as a ligand for first transition series metal catalysts.

    Research

    Heterogeneous (insoluble) metal catalysts, which are easy to separate from the reaction mixture and have excellent reusability, can be used for organic synthesis in an environmentally-friendly manner. However, compared with the corresponding homogeneous (soluble) catalysts, they have a problem of reduced catalytic activity. We have developed a polystyrene-crosslinked bisphosphine ligand, PS-DPPBz, based on the topological control of polymer chains. Since this ligand is effective in generating highly active monochelate mononuclear transition metal complexes, it has significantly improved the efficiency of Ni-catalyzed reactions such as amination coupling of aryl chlorides and ester-azole coupling. PS-DPPBz can also be used for substrates to which it is difficult to apply existing catalysts. PS-DPPBz can be separated by filtration and reused, so it is expected to use this catalyst for industrial purposes.

  • Detoxification and Removal of Nitrogen from Carbon Resources Using Nanoparticles

    Use of nanoparticles for fuel nitrogen pre-removal and high-temperature gas purification

    To establish principles for advanced utilization of carbon resources in harmony with the global environment is one of the most important research themes for the next generation. With this study, we aim to develop a catalytic process that can efficiently convert carbon resources into clean energy using nanoscale metal and metal oxide particles.

    Research

    Nitrogen in carbon resources (Fuel-N) is emitted as NOx and N2O during combustion. During high-temperature gasification, it is mainly converted to NH3, which becomes a source of NOx in later-stage gas combustion. With this study, we have worked on the development of a method to convert Fuel-N into harmless N2 through a pyrolysis process prior to combustion or gasification, and found that Ca ions supported by the ion-exchange method change into CaO nanoparticles during pyrolysis and catalyze the formation of N2 formation.
    We have also found that Fe ions, which are originally contained in lignite coal, and FeOOH, which is abundantly found in brown iron ore, readily become metallic iron nanoparticles during the heating process, and that N2 is selectively produced during the decomposition reaction of NH3, pyridine and pyrrole by this catalyst. Since these N-containing species are contained in the crude gas produced during coal gasification, we are working to develop a new high-temperature gas purification method for the removal of these compounds.

  • Developing Applications of GIS and Geospatial Information

    A human geographical approach to the advanced information society

    GIS (Geographical Information System) is a system for analyzing, searching, and displaying geospatial information (data including location information). In this laboratory, we are developing GIS analysis and visualization methods related to geospatial information for the purpose of supporting regional planning and disaster prevention planning.

    Research

    At this laboratory we are using GIS to study the use of geospatial information, such as Geospatial Information Authority (GSI) maps and digital national land information, maintained by the national government as well as open data maintained by local governments and big data such as movement history acquired by GPS. For example, the results of this research are being used to support the formulation of plans for tsunami evacuation in snowy and cold regions. The winter environment in snowy and cold regions (frozen road surfaces, reduced road width due to snow, etc.) makes tsunami evacuation in coastal areas extremely difficult. At our laboratory we generate a lot of information necessary for planning, such as the demarcation of difficult-to-evacuate areas, the estimation of difficult-to-evacuate populations, and evaluation of the capacity of evacuation sites under such snowy cold conditions, and publish our techniques and results. In this way, we are developing technologies to easily and quickly create socially useful information from a geographical perspective, and are continuing our research to contribute to the formation of the foundation for an advanced information society.

  • Developing Interfaces that Read Users’ Intentions

    Controlling robots and mice freely

    We are developing interfaces that make it possible for users and machines to learn from each other and to operate machines as the users intend. It also facilitates the control of robots and other machines, and input with pointing devices such as mice and trackballs.

    Research

    For a user to operate a multi-degree-of-freedom robot such as a humanoid robot, it is necessary to remember which commands correspond to which operations, and the more commands there are, the harder it becomes for the user. Since it is usually difficult to prepare a set of commands that are easy to remember and use for all, there is no guarantee that the interface created will be easy to use. With this research, we read the user's intentions through the interaction between the user and the machine, and construct an interface that the user can operate intuitively. As a result, we can develop easy-to-use interfaces that match the characteristics of individual users. We are also applying this technology to the development of an air mouse and air trackball that can be operated without a device by sensing the movement of the hand operating the mouse or trackball.

  • Development of a Non-destructive CT-XRD Coupling Method and Its Application

    Visualization of the microstructure of hardened cement

    To develop innovative cement-hardening materials, we are devising a non-destructive integrated CT-XRD method, a novel measurement method combining the CT method to obtain geometric and spatial information on microstructures inside concrete with an accuracy of several microns, and a diffraction method to investigate hydrates and alterations in the region of interest.

    Research

    Concrete is structurally hardened by binding rock (aggregate) through a hydration reaction between cement and water. As a structural material, concrete is intended to withstand loading and certain weather/environmental conditions, but these may cause cracking of the concrete, which may progressively deteriorate due to strong acids and other chemical reactions caused by erosion and materials from the atmosphere, seawater and groundwater that come in contact with it. To stably use the social infrastructure for a long period of time, it is important to be able to see inside the internal structure of concrete with “bug eyes” and find any abnormalities that have occurred.
    With the pioneering “non-destructive integrated CT-XRD method,” the sample is irradiated with high-intensity X-rays from synchrotron radiation to selectively visualize 3D structures from transmitted monochromatic X-rays at 25 keV. Energy-dispersive X-ray diffraction is also performed in specific regions of interest through multiple slit operations to identify hydrates (portlandite, calcite, etc.), their alteration and aggregate minerals.

  • Development of Gd?Si?O?-based High-performance Scintillators and Their Application

    Development of high luminescence scintillators for radiation detectors

    Scintillators are materials that emit light by radiation and are used in medical diagnostic equipment, and for oil exploration and other purposes. Gd2Si2O7 (GPS) scintillators have excellent features such as high luminescence, high energy resolution and non-tidal dissolution, and can be made into single crystals, ceramic plates and powders.

    Research

    The Gd2Si2O7: Ce (GPS) single crystal scintillator has excellent features such as high luminescence (1.4 times that of NaI:Tl), high energy resolution, non-tidal and no self-radioactivity, and can be used in high temperature environments of 250°C or higher. The technology has been transferred to Oxide Corporation, and is now ready for use in SPECT and other applications. We have also established a stable manufacturing technology for 5 cm square GPS sintered plates. By combining a position sensitive photomultiplier tube, it is now possible to detect nuclear fuel materials emitting alpha rays, which were released in the Fukushima Daiichi Nuclear Power Plant accident, with high sensitivity. The prototype device succeeded in detecting nuclear fuel-induced α-ray-emitting radionuclides in an environment with nuclear fuel-induced α-ray-emitting radionuclides: natural radioactivity (radon progeny) = 1:200, which had been inconceivable with conventional devices.

  • Development of Innovative Anodized Aluminum and Their Functions

    When the surface changes, everything changes.

    We will introduce our research on the development of superior properties and new functions of aluminum by innovation of anodizing, which is an extremely well-known corrosion-resistant passive coating for aluminum.

    Research

    Anodic oxide film is an artificial passive film formed on the surface of aluminum, and was developed in Japan about 100 years ago. There are many anodized aluminum products around us, but our research group is reviewing the chemical substances and formation methods (anodic oxidation) used to form anodized aluminum surfaces from the ground up, and we try to develop a new anodizing method that exhibits superior properties and innovative functions. Specifically, we are developing anodized aluminum with highly ordered nanostructures, hard anodized aluminum with a Vickers hardness of Hv = 600 or higher, anodized aluminum with high corrosion resistance in acid, base, and chloride environments, and anodized aluminum that shines beautifully by producing luminescence and structural colors.

  • Development of Mathematical Algorithms for Biomedical Optical Imaging

    Development of a mathematical model for light propagation model inside biological tissues

    A highly accurate and computationally efficient light propagation model is necessary for the progress of biomedical optical imaging. In this study, we have succeeded in constructing a fast solution method for the radiative transfer equation that describes light propagation with high accuracy. We are working on the advancement of an optical diagnosis and treatment using the proposed method.

    Research

    In this study, we are constructing a mathematical algorithm for biomedical optical imaging based on the radiative transfer equation. Our goal is to develop an imaging technique with excellent image resolution that can be applied to biological tissues and body parts where conventional imaging based on mathematical models cannot be applied. Until now, the numerical computational burden of the radiative transfer equation has been enormous, limiting its applicability to small-sized organisms. In this study, we have succeeded in developing a highly accurate and computationally efficient light propagation model by coupling the radiative transfer equation and the photon diffusion equation. Optical imaging based on the developed light propagation model can be applied to various biological tissues and sites. Currently, we are working on applying the model to the optical diagnosis of thyroid tumors in the human neck and the in-vivo evaluation of optical property values in biological tissues.

  • Development of Microstructure Prediction Simulation Technology for Metallic Materials

    From solidification to solid phase transformation

    In the manufacturing process of structural and functional materials, various material structures are formed during solidification, heat treatment, and plastic processing, and the characteristics of these structures determine the properties of the materials. We are developing a simulation method to predict the series of material microstructure changes from solidification to solid phase transformation.

    Research

    We are developing and applying methods for predicting temporal changes in the microstructure of metallic materials during the series of phase transformations that occur in the manufacturing process, such as solidification, grain growth, and diffusional solid transformation. We are specifically engaged in the development of a phase-field model, a method to simulate microstructure formation, and have succeeded in developing a model that calculates the diffusional phase transformation with the highest accuracy in the world. We are also working on microstructure control in various alloy systems by combining experimental approaches, atomistic approaches using molecular dynamics, and information science approaches such as data assimilation and machine learning. We are developing new theories of microstructure formation by using ultra-large scale calculations and obtaining results that lead to optimization of the actual processes.

  • Development of novel control strategies for intractable diseases in animals

    Development of immunotherapy using antibody drugs and protein preparations for chronic infectious diseases and tumors in domestic and companion animals

    In case of intractable diseases, the elimination mechanisms of pathogens and tumors are disturbed in vivo. This is thought to be due to various immunosuppressive factors that exhaust immune cells. the mechanism of eliminating pathogens and tumors in the body is disturbed, probably due to various immunosuppressive factors that exhaust immune cells. This study is aimed to develop novel formulations that target the immune evasion mechanism and apply them as a novel treatment for animal diseases.

    Research

    Research objective: Development of veterinary antibody drugs and protein drugs targeting PD-1 and other immunosuppressive factors and their application to therapeutics. Comparison with and advantage over conventional technology: This approach does not target a specific disease, but rather a wide range of diseases in which the anti-pathogen and anti-tumor effects are lost due to immunosuppressive mechanisms. Since the immunotherapy is based on activated lymphocytes, it is expected to have a multifunctional immune-enhancing effect. Uniqueness of the research: There are limited reports of clinical applications of this approach in the veterinary fields. Characteristics: We will establish therapeutic antibodies for animals and evaluate their effectiveness against various diseases. Efficacy: We aim to provide new treatments for diseases of livestock (cattle, horses, pigs, etc.) and companion animals (dogs, cats, etc.) for which there are no effective vaccines or treatments.

  • Development of Polymer Electrolyte Fuel Cells with Excellent Sub-zero Start-up Performance

    Elucidation of micro-nano freezing phenomena in fuel cells

    We are visualizing the freezing phenomenon near the reaction layer in fuel cells, which cannot normally be observed, using an ultracold electron microscope. By combining electrochemical measurements, we are also elucidating the freezing phenomenon of produced water, which becomes a problem in cold climate applications, and are developing fuel cells with excellent sub-zero activation performance.

    Research

    In the polymer electrolyte fuel cell (PEFC), which is a highly efficient and clean energy conversion device, the water produced by the reaction passes through a catalyst layer pores of several tens of nanometers in diameter and is discharged into the gas diffusion layer and gas supply channel through the microporous layer (MPL), which is a porous layer with pores of several micrometers in diameter, as shown in the left figure below. In the activation in a sub-zero environment in cold regions, the produced water freezes, causing the power generation to stop and degrade. However, the phenomenon is on a micro-nano scale and is thus difficult to measure, so the phenomenon is still insufficiently understood. This study is aimed to clarify where the water freezes and what mechanism leads to performance shutdown and aging degradation. We will conduct microscopic observation, electrochemical measurement and catalyst layer model analysis to contribute to the improvement of activation resistance and extension of the service life. The middle figure below shows the catalyst layer filled with ice, and the right figure is a structural schematic of the catalyst layer modeled in the analysis.

  • Development of Structural Materials for Fusion and High Energy Reactors

    Iron-based composites with high thermal conductivity

    By appropriately arranging high thermal conductive materials in iron-based structural materials, the thermal conductivity of the entire structural materials can be dramatically improved. This will lead to the improvement of the efficiency of energy production and the reduction of radioactive waste, as well as the development of iron-based structural materials for fusion reactors and high energy reactor divertors, for which there has been no solution so far.

    Research

    This paper focuses on the low thermal conductivity of iron-based materials, which are expected to be used in actual DEMO reactors, with a view to the development of heat exchange devices facing to the plasma in operation, and is aimed at a significant improvement of thermal conductivity, which is considered to be the key to success. The 500°C temperature gradient near the cooling tube of the DEMO reactor divertor imposes a huge heat load that has never been experienced in engineering equipment before. On various iron-based materials (pure iron, reduced activation ferritic martensitic steel and oxide dispersion strengthened ferritic steel), Cu and W wires of high thermal conductivity are appropriately arranged to ensure strength as a structural material while serving as a heat sink.

  • Development of Therapeutic Agents and Biomarkers for Stress-induced Diseases

    Molecular psychoneuroimmunology to understand the molecular mechanism of “disease starts in the mind”

    Chronic stress has become a widespread problem in our society as it may lead to sudden death or other serious problems due to overwork or insomnia. We have clarified the molecular mechanism by which chronic stress induces organ damage and sudden death in mice through the activation of specific neural circuits. This system can be used to search for therapeutic targets for stress-induced diseases.

    Research

    We are studying the link between stress and disease. Recently, when autoreactive T cells against central nervous system antigens were transferred to mice that had been subjected to chronic stress, the mice suddenly died. The cause of death was heart failure due to hemorrhage in the stomach and duodenum, as found with humans. Stress-specific activation of neural circuits induced microinflammation in the brain, where transferred T cells, etc. were accumulated in specific blood vessels, and a new neural circuit activated by this triggered the gastrointestinal disorder and heart failure. There have been no animal model of stress in which the molecular mechanism has been elucidated, and this model is useful for screening of new drugs for stress-induced diseases. Using this system, we also identified a group of molecules of which the expression is upregulated in specific blood vessels in the brain during stress, and antibodies against these molecules suppressed sudden death. We are also currently identifying marker candidates for autoreactive T cells in humans.

  • Electrochemically Responsive Organic Dyes

    From electrochromism to multiple responses (fluorescence, circularity)

    Based on cationic organic dyes, which allow easy control of color tone, we offer a group of materials that can respond in multiple ways, including fluorescence and optical rotation (circular dichroism). This technology is designed to suppress the decomposition process of reduced species, and the bi-stability of oxidized and reduced species is such that exchange does not occur, even when they are mixed.

    Research

    Electrochromism is a general term for compounds that change their color tone in response to changes in external electrical potential. As materials that can undergo reversible color changes, they are attracting attention as light control materials for smart windows and display functions for electronic paper. Materials of which not only the color tone, but also fluorescence, optical rotation (circular dichroism), etc. can be changed, enable tailor-made responses according to the application.
    With this technology, we provide a group of substances with multiple responses based on cationic organic dyes of which the color tone can easily be controlled. The reduced species of cationic dyes are generally reactive, and the repeatability of the response is low, but with this technology, the decomposition process of the reduced species is suppressed by incorporating two cationic moieties. The bi-stability of the oxidized and reduced species, in which no exchanges occur, even when they are mixed, makes it possible to apply this technology to high-density recording materials.

  • Elucidation and Application of New Functions of Food by Evaluating the Intestinal Environment

    Development of a new intestinal environment evaluation system for food and medicine

    Food materials and ingredients, intestinal bacteria acting as parasites, and host Paneth cell α-defensins are the three elements that determine the “intestinal environment.” We are developing an intestinal environment evaluation system based on the new paradigm that crosstalk between these three elements affects health maintenance and disease to elucidate food functionality and apply it to disease prevention.

    Research

    In our original definition of “intestinal environment,” three elements, namely, food materials and ingredients, intestinal bacteria acting as parasites, and host Paneth cells α-defensin, determine the “intestinal environment,” and their crosstalk affects health maintenance and disease. This definition has prompted a paradigm shift in food functionality. The purpose of this study is to clarify the involvement of α-defensins in health maintenance, disease development and pathogenesis. This will help us establish a novel functional evaluation system of food and international criteria to evaluate the intestinal environment. By combining a tissue culture system with an α-defensin quantification system, we will lay the foundation for systematic analysis of the relationship between various intestinal functions and food functions of which the mechanisms are still unknown. This will be the first to elucidate immunostimulation and the control of aging substances by digested food materials and ingredients and drugs. We aim to obtain new scientific indicators to create high added value for food.

  • Elucidation of Combustion Phenomena Using Microgravity Fields

    Combustion phenomena are accompanied by a local temperature rise, which always results in natural convection in the surrounding air . This complicates the phenomenon and makes it difficult to fundamentally understand it. In this study, we will try to understand the combustion phenomena from a fundamental standpoint by utilizing the microgravity environment to remove the natural convection.

    Research

    Combustion phenomena are accompanied by a local temperature rise, which always results in natural convection in the surrounding air . This complicates the phenomena and makes it difficult to understand the fundamentals. In this study, we will utilize the microgravity environment to remove the natural convection and understand the fundamental processes (diffusion, heat conduction, soot formation, ignition, flame propagation, etc.) of combustion phenomena, which will be useful for numerical prediction and modeling of combustion devices. Hokkaido University has an approximately 40-meter drop tower that can be used at any time, making it easy to conduct microgravity experiments, and is also involved in international joint research to conduct microgravity experiments using aircraft and the International Space Station. Thus, we are in a favorable environment to conduct combustion research using the microgravity environment.

  • Environmentally Friendly Marine Biofouling Prevention Compounds Derived from Biomass

    Toxic marine anti-biofouling agents against barnacles and other marine organisms are causing pollution to the marine environment, and it is necessary to develop safe alternatives. We have succeeded in creating potent and low-toxicity compounds by synthesizing biomass-derived compounds. Further optimization is also possible.

    Research

    The use of the ocean by mankind (e.g., ships and cooling pipes for power plants) is essential, but marine fouling organisms such as barnacles impairs the fuel efficiency of ships and obstructs the functions, for example by clogging. Organotin compounds have been used to prevent functional impairment, but their use has been banned due to their toxicity, and the development of alternatives is desired. We are focusing on compounds used by marine organisms such as nudibranchs to protect against fouling by other organisms. As a result of synthesizing the compounds, we found functional groups (anti-fouling units) that are important for anti-fouling. The functional group was introduced into inexpensive biomass derived from marine organisms in a short process, and when the synthetic product was tested for anti-fouling (cypris larvae of striped barnacles), they were found to have both very strong anti-fouling activity and very weak toxicity. We are currently conducting research on the synthesis of similar compounds and the addition of further functions.

  • Establishment of Precision Medicine Targeting Cancer Stem Cells Using Synthetic Polymer Gels

    Development of a method to initialize cancer stem cells using hydrogel

    It is important to eradicate cancer stem cells to cure cancer. This method uses Hokkaido University's original biomaterial (synthetic polymeric hydrogel) to induce reprogramming (initialization) of cancer stem cells rapidly and efficiently, making it possible to predict the properties of cancer stem cells and their response to treatment in case of recurrence.

    Research

    It is essential to eradicate treatment-resistant cancer stem cells to cure cancer. However, their number is small, and it is difficult to isolate and analyze cancer stem cells using conventional methods. With this study, we used a synthetic polymeric hydrogel (Science 344, 161-162, 2014) originally developed by Hokkaido University to induce reprogramming (initialization) of cancer stem cells rapidly, easily, inexpensively, and efficiently, allowing us to analyze the properties of cancer stem cells, evaluate their response to treatment, and predict the properties of cancer cells at the time of recurrence. This technology is expected to make it possible to screen drugs that target cancer stem cells, predict the nature of recurrent tumors that may occur in the future, and administer prophylactic drugs, thereby providing cancer patients with accurate cancer stem cell-targeted precision medicine (preventive preemptive medicine).

  • Estimating the State of Radio Waves Using the Compressed Sensing Method

    Toward highly accurate location estimation and channel prediction

    The compressed sensing method is a method to find a solution under certain conditions from a smaller number of observation data than the number of unknowns required. In this study, we use compressed sensing for estimating the direction of arrival of radio waves, to predict the channel, and detect scatterers.

    Research

    It is usually impossible to specify unknowns if their number among observation data is smaller than the number of unknowns that need to be found. However, in case the majority of unknowns are zero, it is sometimes possible to obtain the exact solution. Compressed sensing is a method for obtaining an accurate solution while minimizing the number of observations by using this property. In our laboratory, we are investigating the application of this method to high-precision estimation of the direction of arrival of radio waves as shown in Fig. 1, a method of channel prediction by dividing the incoming wave into elementary waves using this method (Fig. 2), and scatterer detection using the compressed sensing used in radar systems (Fig. 3).

  • Event Information Recommendation System

    A system that collects data from a few weeks before an event to the day of the event and recommends appropriate event information.

    Although event information was only valid for a short time and it was hard to handle it with conventional information recommendation technology, we have developed a flexible recommendation method by combining multiple factors such as user interest and geographic characteristics.

    Research

    The system estimates the genres and information sources that a user prefers based on the user’s past information browsing history, and assesses the event information that the target user is interested in by referring to the browsing trends of users with similar interests. It also takes into account the geographic characteristics of the user and finally presents the information to him/her. The timing of information distribution is adjusted throughout the system so that the overall system performance can be improved.

  • Fabrication of High-speed Superhydrophilic Surfaces and Sliding-controlled Superhydrophobic and Superoleophobic Surfaces

    Both water and oil can soak well into the surface, slide off it easily, and stick to it properly

    We will show you how to create superhydrophilic surfaces that can rapidly be wetted and covered in water, and superhydrophobic and superoleophobic surfaces that repel water/oil very well although their sliding behavior can easily be controlled to allow water/oil to be adsorbed on the surface or easily slide off.

    Research

    Anodizing is a technique used to form oxides with various nanostructures on the surface of metals. We have developed a method to form a large amount of nanofiber oxides with a diameter of sub-10 nm (10 nm or less) by anodizing using a novel electrolyte chemical species. The density of nanofiber formation is extremely high, in the order of 1010 nanofibers (10 billion nanofibers) per cm2. We have found that the metal surface formed with such high-density nanofibers exhibits fast superhydrophilicity of one second or less, as well as superhydrophobicity and superoleophobicity with controlled sliding behavior. It is also possible to mix surfaces with different wettability by using micropatterning techniques.

  • Flexible and Strong Gel

    New materials for the age of welfare

    What kind of material should be used in an age when we are required to improve our quality of life? The answer is strong gels such as double network gels. Tough gels will help revolutionize the quality of medical devices, tissue substitutes and biomimetics.

    Research

    Conventionally, elastomers have widely been used as soft materials, but in situations where they are used as contact points with living organisms or as their substitutes, hydrophobicity is a critically important factor. Since hydrous materials strongly reflect the physical properties of water, they exhibit physical properties that are very similar to biological tissues. For example, heat transfer and electromagnetic wave absorption properties of hydrous materials are similar to those of living tissues, and their surface friction is as low as that of body tissues. Although gel is the most common hydrophilic soft material, its mechanical strength has been low and its application has thus been limited. We have succeeded in developing a highly strong double network (DN) gel that does not break, even when a truck drives over it, despite 90% water content. This has greatly expanded the possibilities of gel applications. While working to examine the toughness of DN gels, we have discovered the “sacrificial bonding principle,” arriving at the concept of strengthening various materials. In recent years, we have been developing various other types of strong gels besides DN gels.

  • Functional Regulators and Biomarkers of Immune and Cancer Cells

    Using low-molecular-weight nucleic acid (microRNA) to control the function of immune and cancer cells, and to determine the immune status of subjects.

    We provide microRNAs that control the immune response of the body and the proliferation of cancer cells. It is expected to be used as a nucleic acid medicine to improve the immune status and to treat cancer patients, and as a new biomarker to determine the immune condition of subjects by monitoring microRNA in the serum.

    Research

    In recent years, cancer immunotherapy has made remarkable progress, and immune checkpoint inhibitors have been marketed as drugs. On the other hand, biomarkers to determine the immune status of subjects are needed to improve the clinical efficacy of cancer treatment and to provide safe and secure treatment with fewer side effects.
    In this study, we discovered novel microRNAs that can regulate the immune responses or cancer cell proliferation. These microRNAs show promise as nucleic acid drugs that can be administered directly to the body to improve the immune status, or as drugs that can be added to immune cells processed or prepared from the body to regulate their functions.
    It is also possible to determine the immune status of cancer patients by monitoring the level of microRNA in the serum, and it is expected to use this as a useful biomarker to evaluate the anti-tumor immune response to cancer immunotherapy and predict side effects caused by abnormal enhancement of the immune system, and to select treatment methods.

  • Gel that is Stronger Than Steel

    Soft and tough composite material

    By conjugating glass fiber and self-healing gel, we have achieved a gel that is stronger than carbon fiber-reinforced plastic (CFRP). Since the base material is a gel, it is as flexible as rubber against bending, but tougher than CFRP against tearing, making it difficult to break.

    Research

    The glass fiber composite gel we have developed exhibits unbreakable, untearable and tear-resistant properties. Generally speaking, CFRP and glass fiber reinforced plastic (GFRP) are widely used as composite materials. Similar to these fiber-reinforced plastics, fiber-reinforced gels are hard and resistant to tension because of the characteristics of the fibers, while being soft and flexible on bending because of the characteristics of the gel. The self-healing polyampholyte (PA) gel used as the base material is also strong as such thanks to its ability to dissipate a large amount of energy against deformation. Since the gel is flexible, when it is combined with fiber, local distortions can be transmitted through the fiber to the distant base material, resulting in large energy dissipation of the entire material, meaning that it is remarkably strong.

  • Geothermal Resource Monitoring and Risk Assessment of Induced Earthquakes

    Monitoring and risk assessment of geothermal resources through geophysical observations

    Evaluation of the subsurface structure necessary for geothermal resource development by gravity survey and precise determination of the seismic source. Monitoring of geothermal reservoir resources by precise gravity measurements and crustal deformation observations. Risk assessment of induced earthquakes associated with geothermal well development and research on seismic activity prediction.

    Research

    ○ For geothermal resource development, which has been actively promoted in recent years, geothermal reservoirs are examined through base structure surveys. We have been investigating the basement structure through gravity surveys, precise seismic source distribution, and seismic velocity structure analysis.
    ○ For geothermal power generation, steam is produced and hot water is returned to the underground, but it is necessary to monitor the level of the geothermal reservoir to ensure the sustainable use of resources. We will examine the appropriate resource utilization volume through physical assessment of the subsurface fluid conditions using precise gravity measurements and crustal deformation observations.
    ○ The injection of high-pressure fluids into geothermal wells may induce noticeable tremors and cause problems. We will provide guidelines for appropriate and sustainable resource development by developing a method to evaluate the risk of induced earthquakes based on such parameters as the crustal stress state in the geothermal development area, surrounding faults, the characteristics of the seismic activity, and fluid injection volume.

  • High-efficiency Semiconductor Solar Cells

    New-type solar cell consisting of a multi-striped semiconductor with orthogonal photon-photocarriers that was coupled to a waveguide.

    Temperature rise and device degradation are suppressed by simultaneous optimization of light absorption and photocarrier collection, as well as photoelectric conversion over the entire solar spectrum by multiple semiconductor stripes. This leads to the realization of a highly efficient 2-dimensional PhotoReceptoConversion Scheme (2DPRCS).

    Research

    In conventional solar cells, there is a trade-off between carrier collection and the number of absorbed photons because the photo carrier migration direction and the light travel direction are parallel. Based on the orthogonality between the carrier migration direction and the light travel direction, it was possible to optimize both the light absorption and the carrier collection efficiency. Since the sunlight is sequentially photoelectrically converted from high- to low-energy components over the entire spectrum, thermal dissipation is minimized and high efficiency can be achieved. A waveguide type light collection system with a light wave direction conversion membrane can realize a photovoltaic system that is resistant to diffuse light. By preventing high-energy photons from entering the mid-gap and narrow-gap semiconductors, bond degeneration can be prevented and the life of the device can be extended. It is possible to realize the ultimate concentrator solar cell system, which is strong even in cloudy weather, has high conversion efficiency close to the thermodynamic limit, and is highly reliable.

  • High-precision Acoustic Position Recognition, Time Synchronization, Selective Flickerless Visible Light Communication

    Submillimeter-order position measurement and its deployment

    By integrating ranging technology that is more accurate than conventional methods by double digits and original time-synchronization technology using illumination, we can quickly and accurately estimate the 3D position and velocity of mobile terminals and robots. The system also realizes selective flickerless visible light communication and position-dependent information distribution to specific moving objects.

    Research

    To accurately obtain the position of a user in a room or a moving object in real time, we have proposed a high-precision time reference point setting method called the phase-matching method (ranging error of 0.03 mm). Based on this technology, we have developed a smartphone users’ gesture recognition system and a robot tracking system. We have also achieved microsecond-order time synchronization using a camera-equipped mobile terminal and an original algorithm. The integration of LED modulation and terminal location information will allow us to distribute location-dependent information and conduct flickerless visible light communication using indoor lighting.

  • High-temperature Latent Heat Storage Microcapsules

    Core (alloy latent heat storage material) ? shell (Al2O3) type latent heat storage microcapsules capable of high-density heat storage in the high temperature range of over 500?C

    The latent heat storage method, which utilizes latent heat generated during the solid-liquid phase change, is attractive for its high-density heat storage capacity. Microencapsulation of latent heat storage material enables not only heat storage but also heat transport and heat control applications, and we have developed latent heat storage microcapsules that can be used in the high temperature range of over 500°C.

    Research

    An Al-base alloy with a melting point above 500°C was newly discovered as a latent heat storage material. By skillfully applying chemical conversion/oxidation treatment to the micro-particles of this alloy (approx. 20 μm or larger), we have succeeded in developing core (Al-base alloy) and shell (Al2O3) type latent heat storage microcapsules (Fig. 1). These microcapsules have high heat storage capacity of approximately five times that of solid sensible heat storage materials, and have excellent mechanical properties. Since the shell is made of Al2O3, it can also be treated as a ceramic particle. In other words, it is an epoch-making heat storage material of which the performance can be upgraded while maintaining the current use of ceramic sensible heat storage technology.