NATIONAL CHENG KUNG UNIVERSITY, TAINAN, TAIWAN
BANYAN
Volume 20 Issue 3 - October 21, 2011
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Commentary
THE ROYAL SWEDISH ACADEMY OF SCIENCES
THE NOBEL PRIZE IN CHEMISTRY 2011
Crystals of golden proportions
Article Digest
Yun Chen
Multi-functional Hyperbranched Oligo(fluorene vinylene) Containing Pendant Crown Ether: Synthesis, Chemosensory and Electroluminescent Properties
Chi Wang
Syndiotactic polystyrene nanofibers obtained from high-temperature solution electrospinning process
LihChyun Shu
Continuous Reverse k-nearest Neighbor Monitoring on Moving Objects in Road Networks
Article Digest
Sheng-Tzong Cheng
New hybrid methodology for stock volatility prediction
News Release
Banyan Forum
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THE NOBEL PRIZE IN CHEMISTRY 2011
Crystals of golden proportions
When Daniel Shechtman entered the discovery awarded with the Nobel Prize in Chemistry 2011 into his notebook, he jotted down three question marks next to it. The atoms in the crystal in front of him yielded a forbidden symmetry. It was just as impossible as a football - a sphere - made of only six-cornered polygons. Since then, mosaics with intriguing patterns and the golden ratio in mathematics and art have helped scientists to explain Shechtman's bewildering observation.

"Eyn chaya kazo", Daniel Shechtman said to himself. "There can be no such creature" in Hebrew. It was the morning of 8 April 1982. The material he was studying, a mix of aluminum and manganese, was strange-looking, and he had turned to the electron microscope in order to observe it at the atomic level. However, the picture that the microscope produced was counter to all logic: he saw concentric circles, each made of ten bright dots at the same distance from each other (figure 1).

Shechtman had rapidly chilled the glowing molten metal, and the sudden change in temperature should have created complete disorder among the atoms. But the pattern he observed told a completely different story: the atoms were arranged in a manner that was contrary to the laws of nature. Shechtman counted and recounted the dots. Four or six dots in the circles would have been possible, but absolutely not ten. He made a notation in his notebook: 10 Fold???
Figure 2. Light passing through a diffraction grating gets scattered. The resulting waves interfere with each other, giving a diffraction pattern.
Figure 1. Daniel Shechtman’s diffraction pattern was tenfold: turning the picture a tenth of a full circle (36 degrees) results in the same pattern.


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