摘要：Computer aided design of heat treatment for AISI P20 mold steel with good machinability is attempted to proceed by the commercial software package Thermo-Calc (TCP+DICTRA). Through experimental and theoretical analysis of phase transformation during heat treatment, further knowledge of designing proper heat treatment is obtained. Then the machinability of AISI P20+Ni steel under given heat treatment condition is studied and the influencing factors to their machinability are analyzed. It is shown that heat treatment designed by computer simulation of carbide transformation is applicable to AISI P20+Ni steel with good machinability; AISI P20+Ni steel with tempered sorbite treated by quenching & tempering has optimal machinability; normalizing at the temperature of 910°C & tempering can avoid cracking and result in acceptable machinability in small thickness module.

摘要：萱草属(Hemerocallis)植物依据花朵的开放时间分为夜间开花型和白天开花型两类。为研究萱草花朵开放和闭合的规律,对3种夜间开花的萱草种和品种以及4种白天开花萱草品种进行了杂交,设计了4对杂交组合,每个组合包括正反交,共获得F1代386株。此外,研究了16个辅助杂交组合,后代共208株。2012年和2013年夏季对全部植株的花朵开放和闭合时间进行观测。对于花朵开放时间,北黄花菜(Hemerocallis lilio-asphodelus)和黄花菜(***)做亲本的杂交组合后代中99.74%的植株表现为夜间开放;黄花菜品种‘四月花’(H.‘April Flower’)做亲本的各杂交组合中夜间开花的‘诺米路’ב四月花’杂交组合的后代全部表现为夜间开放;与白天开花型杂交的3个组合后代中夜间开放类型与白天开放类型株数的比例接近1∶1或3∶1。花朵闭合时间变异较大,黄花菜和北黄花菜做亲本的杂交后代主要集中在夜间和白天闭合;‘四月花’杂交后代在一天中各个时段均有闭合。结果表明:萱草花朵开放与闭合是受不同基因控制的;花朵开放受一个主基因控制,夜间开花性状是显性,白天开花则为隐性性状;控制花朵开放时间的基因属于核基因;萱草花朵闭合时间表现复杂,可能受多基因调控。