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"J" Researcher: 4
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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.
Jian Ping Gong Professor -
Soft Viscosity Ferroelectric Crystal
Development of organic ferroelectrics with freely controllable polarization direction
We have developed a ferroelectric material using deformable flexible crystals. This material can easily be processed in solution and can be stretched under pressure. Unlike conventional organic ferroelectrics, the material can be polarized in three dimensions, so that even discs and thin films of microcrystalline powder exhibit large polarization like single crystals.
Research
Ferroelectrics are important electronic materials with a variety of applications, such as non-volatile memories, piezoelectric devices and sensors that take advantage of their diverse functions. Most of the ferroelectrics that have been commercialized so far are inorganic oxides, such as barium titanate, which are known as chitabari in Japan. However, they are difficult to process using the solution method, and many of the useful materials contain toxic lead. Organic ferroelectric crystals, which have been actively developed in recent years, cannot be used in polycrystalline materials because polarization processing that changes the polarization direction in three dimensions is impossible. The flexible ferroelectric crystals we have recently developed can change the polarization direction almost freely, so that the polarization direction of polycrystals in disks and thin films can be aligned to create a polarization state close to that of a single crystal. They can also be stretched and expanded under pressure at high temperatures. In other words, this flexible ferroelectric crystal is a ferroelectric material that combines the advantages of conventional materials such as inorganic oxides, organic crystals and polymers.
Jun Harada Associate Professor -
Techniques for Listening to Opinions That Are Difficult to Express Verbally
Unconscious Attitude Measurement Using Latent Association Analysis
People do not always say what is on their minds, and may hide their true feelings in questionnaires and interviews. Latent association analysis is a technique that enables measurement of attitudes that are difficult to express face-to-face, using a five-minute-long online game-like interface.
Research
Some people in a questionnaire or interview may give “desirable and exemplary” answers based on common sense, interpersonal relationships, and social norms when they are asked what their impressions are of a certain product or service. By using a method called the implicit association test (IAT), we can get closer to their true feelings, which are difficult to reveal consciously. It can be applied to the measurement of not only good and bad feelings, but also a variety of other emotional states.
Jun-ichiro Kawahara Professor -
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.
Junichi H. Kaneko Associate Professor