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International Affairs Students Current Students Alumni Faculty/Staff Careers--> TOHOKU UNIVERSITYCREATING GLOBAL EXCELLENCE Search 日本語 Contact Tohoku University --> About Facts & Figures Facilities Organization Chart History President's Message Top Global University Project Designated National University Global Network Promotional Videos Academics Undergraduate Graduate Courses in English Exchange Programs Summer Programs Double Degree Programs Academic Calendar Syllabus Admissions Undergraduate Admissions Graduate Admissions Fees and Expenses Financial Aid Research Feature Highlights Research Releases University Research News Research Institutes Visitor Research Center Research Profiles Academic Research Staff Campus Life International Support Office IT Services Facilities Dining & Shops Campus Bus Clubs & Circles News University News Research--> Arts & Culture Health & Sports Campus & Community Press Release--> International Visit Alumni Careers Events Exhibits Music Special Event Lecture Alumni--> Map & Directions Campus Maps & Bus--> Facilities Map--> TOHOKUUNIVERSITY About Academics Admissions Research Campus Life News Events International Affairs Students Current Students Alumni Faculty/Staff Promotional Videos Subscribe to our Newsletter Map & Directions Contact Jobs & Vacancies Emergency Information Site Map 日本語 Close Home Research Feature Highlights A Crystal-Clear Passion Feature Highlights A Crystal-Clear Passion For almost 30 years, Tohoku University professor An-Pang Tsai has been fascinated by the beautiful structures of quasicrystals The pattern was too clear to deny. Observing a transmission electron micrograph, An-Pang Tsai spotted a dense array of spots arranged in inflating pentagons and decagons -- a pattern he knew must have been produced by a remarkable material known as a quasicrystal. "It just looked so beautiful," he recalls. Originally from Taiwan, Tsai had come to Japan more than three decades ago as an international student in a bachelor's degree program and stayed on to enroll as a master's and then PhD student at Tohoku University, when he made his captivating observation. It was the beginning of a career-long passion for the man who now leads the university's Metallurgical Design for Material Functions Tsai Lab. Conventional crystals consist of periodical arrangements of three-dimensional units, such as interlocking triangles, squares or hexagons. But in 1982, Israeli materials scientist Dan Shechtman discovered an entirely new category of crystals that broke the normal rules. Made up of five- and ten-angled polygons, these materials -- dubbed quasicrystals -- cannot produce such perfectly packed lattices. This concept was unheard of for ordered solid systems, and Shechtman's initial discovery met with skepticism from the scientific community. Electron diffraction pattern showing five-fold symmetry obtained from the stable aluminum-copper-iron quasicrystal. This pattern convinced scientists of the existence of quasicrystals. The pattern Tsai saw in 1987 helped build the case for quasicrystals. He observed a stable quasicrystal with a highly ordered structure, as evidenced by the high density of sharp spots in the diffraction pattern. He produced this quasicrystal using a simple, replicable technique that involved heating a mixture of aluminum, copper and iron, and then slowly cooling the alloy. Scientists can now easily grow a millimeter-sized single quasicrystal with a pentagonal dodecahedral structure. A metallurgist by training, Tsai proceeded to experiment with other mixtures. He replaced iron with other elements in the same group in the periodic table, such as the transition metals ruthenium and osmium that have similar electron distributions as iron. Each time he was able to produce a new quasicrystal having the same curious diffraction symmetry, suggesting a non-uniform lattice. These experiments unveiled the general principle that all the alloys in a family of quasicrystals share the same ratio of electrons to atoms. In 1992, the growing body of evidence for the existence of such solid structures led the International Union of Crystallography to subtly redefine crystals, shifting the emphasis from the repetitive atomic structure of crystals in real space to their representation in reciprocal space, as observed by transmission electron microscopy. In 2000, Tsai's team produced the first stable quasicrystal containing two elements -- cadmium and ytterbium -- and seven years later presented a detailed atomic structure of the alloy, the first of its kind. Around thirty stable quasicrystals composed of a mixture of three metals have since been concocted, of which Tsai has directly contributed to over twenty. Tsai was thrilled when Shechtman won a Nobel Prize in 2011 for his initial discovery. The two had become close colleagues over the years and would sometimes visit each other in Japan or Israel. In his Nobel lecture, Shechtman even presented some of Tsai's images. "As someone working in the field of quasicrystals, I also share the honor," says Tsai. The challenge now is to find practical ways to use quasicrystals. French researchers found that some of these materials display low friction and high resistance to wear, which could be exploited in nonstick frying pans or to reduce energy loss in applications such as car engines. A few alloys also show low thermal and electrical conductivities. Furthermore, researchers in Nagoya recently observed quantum critical phenomena in a quasicrystal. Tsai's lab at Tohoku University has also produced excellent catalysts for hydrogen production. For Tsai, these developments make the field of quasicrystals more interesting today than it ever has been. "When you find something that you enjoy," he advises, "you should never let it go." Links: Metallurgical Design for Material Functions TSAI Lab Professor An-Pang Tsai Metallurgical Design for Material Functions, Tsai Lab, Institute of Multidisciplinary, Research for Advanced Materials Awards Medal of Honor with Purple Ribbon -- 2014 Japan Institute of Metals, Masumoto Hakaru Award -- 2013 Honorary Doctorate from the Institut National Polytechnique de Lorraine, France -- 2009 Honda Frontier Award -- 2008 Jean-Marie Dubois Award -- 2005Japan IBM Science Award -- 1994 Feature Highlights 2018-05-11 In Conversation with Susumu Satomi 2018-04-04 Motoko Kotani: By the Numbers 2018-02-02 Yoshimichi Sato: Making Rational Choices 2017-09-07 Anawat Suppasri - Carried by the Waves 2017-05-30 Kyoko Sengoku-Haga: A Portrait of the Artist as an Historian 2017-04-19 Aiming high: Shigeru Obayashi is innovating human flight 2017-01-17 Exploring the Earth and its neighbors 2016-11-04 YUI Project - Ties that Bind and Save Lives 2016-10-12 Sea Change 2016-08-22 Brain training turns back your cognitive clock 2016-07-11 Forcing liquids into a squeeze 2016-06-03 Brain buster: Noriko Osumi is uncovering the links between genetics and brain development 2016-05-26 Sparking the next revolution in data science 2016-05-10 Taking memory for a spin 2016-04-11 Fueling the hydrogen revolution 2016-01-12 A Planner by Design 2015-10-29 Robo Rescue! 2015-10-01 Understanding Muscles 2015-08-31 Some sense of touch 2015-07-31 Surrogacy and the Law Page Top About Tohoku University Academics Admissions Research Campus Life News Events International Affairs Students Alumni Promotional Videos Subscribe to our Newsletter Map & Directions Contact Tohoku University Jobs & Vacancies Emergency Information Site Map Media Enquiries Parent & Family Support Public Facilities Contact Tohoku University