A flow injection method is proposed for determining vanadium（V）. The method is based on its catalytic effect on the oxidation of malachite green oxalate by bromate. The reaction was monitored spectrophotometrically ...A flow injection method is proposed for determining vanadium（V）. The method is based on its catalytic effect on the oxidation of malachite green oxalate by bromate. The reaction was monitored spectrophotometrically by measuring malachite green oxalate absorbance at λmax = 625 nm. The reagents and manifold variables, which have influences on the sensitivity, were investigated and the optimum conditions were established. The optimized conditions made it possible to determine vanadium in the ranges of 10-140 ng/mL with a detection limit of 5.2 ng/mL and a sample rate of 20 ± 5 samples/h.展开更多
The fracture splitting property of medium carbon steel 37MnSiS microalloyed with V up to 0. 45% was investigated by using simulated fracture splitting test,for the development of new crackable medium carbon steel to m...The fracture splitting property of medium carbon steel 37MnSiS microalloyed with V up to 0. 45% was investigated by using simulated fracture splitting test,for the development of new crackable medium carbon steel to manufacture high performance connecting rod. Conventional high carbon steel C70S6 was used for comparison. The results show that the volume fraction of both ferrite and V-rich M（ C,N） particles increases,and the pearlite interlamellar spacing decreases with increasing V content,which in turn results in gradual increase of strength and decrease of ductility and impact energy. The fracture splitting property of the tested steel could be improved significantly due to the increase of V content mainly through the precipitation hardening mechanism of fine M（ C,N） precipitates. The fraction of brittle cleavage fracture in the crack initiation area increases noticeably with increasing V content and full brittle cleavage fracture surface could be obtained when V content was increased to 0. 45%. It is concluded that medium carbon steel with V content higher than about 0. 28% possesses not only comparable or even higher mechanical properties with those of conventional steel C70S6,but also excellent fracture splitting property,and therefore,is more suitable to fabricate high performance fracture splitting connecting rod.展开更多
文摘A flow injection method is proposed for determining vanadium（V）. The method is based on its catalytic effect on the oxidation of malachite green oxalate by bromate. The reaction was monitored spectrophotometrically by measuring malachite green oxalate absorbance at λmax = 625 nm. The reagents and manifold variables, which have influences on the sensitivity, were investigated and the optimum conditions were established. The optimized conditions made it possible to determine vanadium in the ranges of 10-140 ng/mL with a detection limit of 5.2 ng/mL and a sample rate of 20 ± 5 samples/h.
基金Item Sponsored by National High Technology Research and Development Program of China(2013AA031605)
文摘The fracture splitting property of medium carbon steel 37MnSiS microalloyed with V up to 0. 45% was investigated by using simulated fracture splitting test,for the development of new crackable medium carbon steel to manufacture high performance connecting rod. Conventional high carbon steel C70S6 was used for comparison. The results show that the volume fraction of both ferrite and V-rich M（ C,N） particles increases,and the pearlite interlamellar spacing decreases with increasing V content,which in turn results in gradual increase of strength and decrease of ductility and impact energy. The fracture splitting property of the tested steel could be improved significantly due to the increase of V content mainly through the precipitation hardening mechanism of fine M（ C,N） precipitates. The fraction of brittle cleavage fracture in the crack initiation area increases noticeably with increasing V content and full brittle cleavage fracture surface could be obtained when V content was increased to 0. 45%. It is concluded that medium carbon steel with V content higher than about 0. 28% possesses not only comparable or even higher mechanical properties with those of conventional steel C70S6,but also excellent fracture splitting property,and therefore,is more suitable to fabricate high performance fracture splitting connecting rod.
