[No. 42] Naoyuki Taketoshi

The most important thing in research is to have a major goal and to be "persistent" in pursuing it. In my case, I believe I acquired the foundation that supports this "persistence" at the Faculty of Science and Technology, Keio University, especially in the Department of Physics.

I chose the Department of Physics simply because I found physics interesting. I don't think there was much logic behind it. If I had to say, I was fascinated by the aspect of physics that involves finding things that do not change (are conserved)—such as energy or momentum—and using them as a basis to systematically explain phenomena.

In my fourth year of undergraduate studies and during my master's program, I joined a theoretical research laboratory. The theory lab had many world-renowned professors, and looking back, I realize that attending their seminars and lectures was an incredibly privileged experience.

For my undergraduate and master's theses, I conducted computer simulations on the theme of scaling laws in polymer systems under the guidance of Professor Takano and Professor Kawamura. Scaling laws deal with universal properties that are independent of the chemical bonds of polymers, and it was a topic I personally enjoyed.

I had a wealth of experiences in the Department of Physics. I had weekly discussions (in English...) with a foreign part-time lecturer in an endowed course, presented at academic conferences every spring and fall, and served as a teaching assistant, helping to guide first-year undergraduate students in mechanics and electromagnetism exercises and grading their reports. I believe I was given more opportunities than others to acquire a foundation in physics, even outside of regular lectures.

After completing my master's program, I joined the National Research Laboratory of Metrology, which was then under the Agency of Industrial Science and Technology. It has since been reorganized and is now the Metrology Institute of Japan at the National Institute of Advanced Industrial Science and Technology (AIST), an independent administrative agency.

The Metrology Institute of Japan is responsible for the nation's "standards." You are surrounded by many "measuring instruments" such as rulers, scales, thermometers, and gas meters. To ensure, for example, that the markings on a ruler are truly correct, it is necessary to check it against a ruler with even finer markings. The Metrology Institute of Japan is the institution that guarantees these markings for the nation, and it holds the "national standards"—the "measuring instruments with the highest precision markings"—for fundamental quantities like length, temperature, and time. Here, we not only maintain a system to ensure that the reliability of the markings on various "measuring instruments" in Japan can be traced back to these "national standards," but we also conduct experimental verifications with related research institutions abroad to ensure our markings align, and we promote basic research to further improve the precision of the national standards' markings.

As you can see from the above, it is clear that to do research in this department, one is essentially useless without experimental skills. In fact, the theme I was given was thermophysical property measurement technology for thin films. My task was to develop a technology to non-contactly and quantitatively measure the thermal conductivity of thin films using a laser and to establish standards for it.

Naturally, for the first year, I produced no results and made no progress. A master's graduate who had been doing Monte Carlo simulations of polymer systems on a computer in a theoretical physics lab could not be expected to achieve results in experiments right away. To be honest, I felt a sense of inferiority for quite a long time, and it would be a lie to say I wasn't bewildered when I first tackled the task.

However, I gradually became accustomed to developing equipment and began to produce results little by little. Looking back now, I believe the reason this developed into a virtuous cycle was that I was able to continue my research "persistently." I self-analyze that one of the things that supported this "persistence" was the foundation in physics that was drilled into me as a student. When you actually engage in measurement technology as a practitioner, you find that its principles are based on physical phenomena. Electromagnetism, mechanics, optics, statistical mechanics, mathematical physics—none of these were useless when considering what the measuring instruments I was using were actually observing. This fundamental knowledge of physics has a wide range of applications, and I believe I was able to "persist" by applying it, despite my limited knowledge.

Another thing that supported my "persistence" was a quote from Professor Kawamura, who was my academic advisor and the Head of the Department of Physics at the time: "A physicist must tackle anything and everything with curiosity." I can't recall the exact situation in which he said it, but it's natural that if you can find interest in the unknown, you can persist. This is a mindset that is easy to forget when you are struggling. I think I was very lucky that, conveniently, events that served as triggers to remember those words occurred just when I was having a hard time. I was invited to many weddings of my seniors from the theory lab, I had opportunities to speak to students in the Department of Physics as a part-time lecturer at Keio University, and I was asked to write this article. Even after graduating, I had various connections, and these things happened just when I was about to forget his words.

Aided by good fortune, this research gained support from the institute and I was able to carry it out continuously. Thanks to this, I was able to produce substantial results, and with the enthusiastic support of Professor Nagasaka of the Department of System Design Engineering, Graduate School of Science and Technology at Keio University, whose work is closely related to this theme, I was able to compile it into a doctoral dissertation.

Currently, while continuing to advance my research, I am also working to give back to society by transferring some of the results to private companies and ensuring that standards based on the technologies I was involved in are supplied. I don't just let my research end as research, and I lead a fulfilling life every day.

The fundamental stamina for physics I developed at the Department of Physics at Keio and the words from my professor are a lifelong treasure that will never be lost.