Chinese surnames are used by Han Chinese and Sinicized ethnic groups in Mainland China, Hong Kong, Macau, Malaysia, Taiwan, Korea, Singapore, Vietnam and among overseas Chinese communities. In ancient times two types of surnames existed, namely xing (Chinese: å§; pinyin: xÃ¬ng) or lineage names, and shi (Chinese: æ°; pinyin: shÃ¬) or clan names.
An ice sheet is a large permanent layer of ice covering a continental shelf, defined as having an extent greater than 50,000 km2 (19,305 mi2). An ice sheet is larger than a glacier or ice shelf.
Ice melts when heat energy causes the molecules to move faster, breaking the hydrogen bonds between molecules to form liquid water. In the melting process, the water molecules actually absorb energy. This is why an ice cube melts more quickly on the outside and retains its coldness and solidity longer at the center: melting is a cooling process. As more heat is introduced, the ice will continue to melt, and if the temperature exceeds the boiling point, about 100 degrees Celsius (212 degrees Fahrenheit), more hydrogen bonds between water molecules will break completely, creating water vapor.