X2CrNiMoN25-7-3 duplex stainless steel is suitable for chloride-containing environments such as seawater because it has excellent pitting corrosion resistance. Duplex stainless cast steel is often used to accommodate ...X2CrNiMoN25-7-3 duplex stainless steel is suitable for chloride-containing environments such as seawater because it has excellent pitting corrosion resistance. Duplex stainless cast steel is often used to accommodate the complexity of part geometry at joints. However, machining after casting is indispensable. This study evaluated the cutting characteristics of stainless cast steel. Adhesion of the cutting edge was weak at high cutting speeds, but tool wear was large. Diffusion and reactions between the work-pieces and the tool edge were investigated. Slight inter-diffusion and a reaction phase were observed, but the bond-ability was low.展开更多
A novel and concise synthetic access to enantiopure chiral 2-aryl/alkyl substituted 4-piperidone has been demonstrated.This new route features two key steps:the highly diastereoselective conjugate addition of homochir...A novel and concise synthetic access to enantiopure chiral 2-aryl/alkyl substituted 4-piperidone has been demonstrated.This new route features two key steps:the highly diastereoselective conjugate addition of homochiral lithium amides to trans-β-substituted-α,β-unsaturated methyl esters guaranteed the enantiopurity at 2 position(de>19:1)and the intramolecular attacking of carbanions to methyl esters led to the formation of the piperidone ring.A wide range of substrates,including chiral2-aryl and 2-alkyl-4-piperidones,were successfully synthesized with modest to high yield.Moreover,some non-chiral3-substituted-4-piperidones were also synthesized with enhanced ring-formation yield,implicating the versatility of this method in construction of various piperidine rings.展开更多
文摘X2CrNiMoN25-7-3 duplex stainless steel is suitable for chloride-containing environments such as seawater because it has excellent pitting corrosion resistance. Duplex stainless cast steel is often used to accommodate the complexity of part geometry at joints. However, machining after casting is indispensable. This study evaluated the cutting characteristics of stainless cast steel. Adhesion of the cutting edge was weak at high cutting speeds, but tool wear was large. Diffusion and reactions between the work-pieces and the tool edge were investigated. Slight inter-diffusion and a reaction phase were observed, but the bond-ability was low.
基金CAS Key Laboratory of Synthetic Chemistry of Natural Substances (2008DP173071) for analysis support
文摘A novel and concise synthetic access to enantiopure chiral 2-aryl/alkyl substituted 4-piperidone has been demonstrated.This new route features two key steps:the highly diastereoselective conjugate addition of homochiral lithium amides to trans-β-substituted-α,β-unsaturated methyl esters guaranteed the enantiopurity at 2 position(de>19:1)and the intramolecular attacking of carbanions to methyl esters led to the formation of the piperidone ring.A wide range of substrates,including chiral2-aryl and 2-alkyl-4-piperidones,were successfully synthesized with modest to high yield.Moreover,some non-chiral3-substituted-4-piperidones were also synthesized with enhanced ring-formation yield,implicating the versatility of this method in construction of various piperidine rings.
