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Perforated cold-formed steel (PCFS) beams are increasingly used in constructional industry and become popular due to their advantages and economic benefit. Apart from the light weight, the openings in PCFS beams can also be used for services such as pipe utilities to release more building space. However, beams with web perforations may collapse as the result of web-distortional buckling or flange/web distortional buckling due to the web weakness caused by perforations. In this paper a study on the flange/web distortional buckling of PCFS beams is presented. An analytical solution to determine the critical stress of flange/web distortional buckling of PCFS beams is derived by using energy method. To demonstrate the analytical solution, finite element analysis is also carried out. The finite element analysis results show that the analytical solution provided can give good and reliable prediction for the flange/web distortional buckling of PCFS beams. [ABSTRACT FROM AUTHOR]

Objective: To analysis the constituents of volatile oil from Fructus Auranti Immaturus by GC-MS., Methods: The volatile oil was extracted by steam distillation, then separated by capillary gas chromatography. The constituents of volatile oil were identified and their amount were determined by normalization method., Results: Nineteen components were identified from Fructus Auranti Immaturus and their amount accounted 95.791% of total volatile oil. The main components were Limonene (68.25%), gamma-Terpinene (13.02%), alpha-Terpinol (3.28%), beta-Cymene (3.09%), beta-Myrcene (2.34%), alpha-Pinene (1.53%), beta-Pinene (1.05%)., Conclusion: The main component of volatile oil from Fructus Auranti is Limonene.