Changing environmental conditions, especially temperature, have been observed to be a complicated factor affecting vibration properties, such as frequencies, mode shapes, and damping, of civil structures. This paper reviews technical literature concerning variations in vibration properties of civil structures under changing temperature conditions. Most of these studies focus on variations in frequencies of bridge structures, with some studies on variations in mode shapes and damping and other types of structures. Statistical approaches to correlation between temperature and frequencies are also reviewed. A quantitative analysis shows that variations in material modulus under different temperatures are the major cause of the variations in vibration properties. A comparative study on different structures made of different materials is carried out in laboratory. Two real structures, the 1377 m main span Tsing Ma Suspension Bridge and the 610 m tall Guangzhou New Television Tower, are examined. Both laboratory experiments and field testing, regardless of different construction materials used and structural types, verify the quantitative analysis. Variations in frequencies of reinforced concrete (RC) structures are much more significant than those of steel structures.

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CuBr and ZnI(2) have been developed as catalysts or subcatalysts for the efficient asymmetric synthesis of axially chiral allenols with up to 97% ee from readily available propargylic alcohols, aliphatic or aromatic aldehyde, pyrrolidine, and commerically available ligands. The alcohol unit in the terminal alkynes plays a very important role for ensuring high enantioselectivity via coordination.