1. Department of Materials Science and Engineering Korea University Seoul 02841 Republic of Korea
2. Department of Civil Engineering The University of Hong Kong Hong Kong
3. Department of Energy and Materials Engineering Dongguk University‐Seoul Seoul 04620 South Korea
4. Department of Physics City University of Hong Kong Kowloon Tang Hong Kong
5. National Synchrotron Radiation Research Center Hsinchu 30076 Taiwan ROC