Bamboo is a fast-growing biobased building material with a high strength-to-weight ratio, and the combination of bamboo and wood provides an environmentally friendly alternative for building construction. A new type of laminated bamboo-timber composite column was proposed to improve the compressive performance of timber columns, which was expected to obtain better mechanical performance. Bamboo scrimber and Douglas fir were combined to form laminated bamboo-timber composite columns for the experimental study. Axial compression tests were carried out on 5 groups of 15 composite columns. The failure modes of the composite columns were assessed. The laws of axial displacement, lateral displacement, axial strain, ultimate bearing capacity and stiffness were analyzed. Finally, the bearing capacity of the composite columns was calculated by referring to the design specification for timber structures. The results indicated that the composite columns exhibited three failure characteristics. The ultimate bearing capacity and stiffness of the bamboo-timber composite columns increased with increasing amount of bamboo scrimber. The ultimate load of the bamboo-timber composite columns was increased by 23.0-94.6%, while the stiffness was increased by 9.1-38.4%. In addition, the bearing capacity of composite columns was calculated according to two standards. The experimental values of the bamboo-timber composite columns are in good agreement with the theoretical values, and the errors are within 8%.
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A reliable LC-MS/MS method for the determination of five bioactive constituents (bilobalide, BLL; ginkgolide A, GLA; ginkgolide B, GLB; ginkgolide C, GLC; rutin) of Ginkgo biloba leaf extracts (GBE) in rat plasma was established, fully validated and applied to an intragastric pharmacokinetic study of a preparation of GBE in rat. Samples were extracted with ethyl acetate. C18 column was selected as analytical column in this method. Mobile phase was water with 0.01% formic acid and acetonitrile. Quantification was performed in negative multiple-reaction monitoring mode. Matrix instability of terpene lactones was noticed and hydrochloric acid was used as a stabilizer. This method showed good precision and accuracy, recovery was reproducible and matrix effect was negligible. Among four terpene lactones, BLL had the highest exposure and the shortest terminal half-life, GLA and GLB had lower exposure and longer terminal half-life, the exposure of GLC was lowest and its terminal half-life was the maximum, and all of them showed rapid absorption. This study provides a reference for determination of terpene lactones and flavonol glycoside prototypes in GBE and offers pharmacokinetic data of flavonol glycoside prototype in GBE.
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