AISI 304L is an austenitic Chromium-Nickel stainless steel offering the optimum combination of corrosion resistance, strength and ductility. These attributes make it a favorite for many mechanical components. The pape...AISI 304L is an austenitic Chromium-Nickel stainless steel offering the optimum combination of corrosion resistance, strength and ductility. These attributes make it a favorite for many mechanical components. The paper focuses on developing mathematical models to predict grain size and hardness of pulsed current micro plasma arc welded AISI 304L joints. Four factors, five level, central composite rotatable design matrix is used to optimize the number of experiments. The mathematical models have been developed by Response Surface Method (RSM) and its adequacy is checked by Analysis of Variance (ANOVA) technique. By using the developed mathematical models, grain size and hardness of the weld joints can be predicted with 99% confidence level. The developed mathematical models have been optimized using Hooke and Jeeves algorithm to minimize grain size and maximize the hardness.展开更多
上海作为我国最大的城市之一,人口密集,人类活动频繁,原生植被物种多样性受人为干扰严重。作为古老的孑遗植物,蕨类植物对生长和繁殖环境要求严格,能够灵敏地指示环境变化。为摸清上海市国土空间生态环境现状,调查团队在上海市全域土地...上海作为我国最大的城市之一,人口密集,人类活动频繁,原生植被物种多样性受人为干扰严重。作为古老的孑遗植物,蕨类植物对生长和繁殖环境要求严格,能够灵敏地指示环境变化。为摸清上海市国土空间生态环境现状,调查团队在上海市全域土地综合整治项目区内展开长期定点监测,期间在奉贤区西渡街道辖区发现了上海蕨类植物新记录种——柄叶瓶尔小草(Ophioglossum petiolatum Hook.)。文章对新记录种的形态特征和发现生境进行描述,讨论了Flora of China与《云南植物志》对其形态描述的差异,认为《云南植物志》中的描述与原始发表文献和模式标本更为接近,即该种的重要特征为其不育叶的基部下延呈柄状。柄叶瓶尔小草在江浙沪地区亦属首次报道,此次发现扩大了该种向东和北的分布记录,对研究蕨类区系分布有推进作用;瓶尔小草属植物近年来在华东地区较为罕见,本次发现地位于上海市全域土地综合整治项目区内的生态公益林,彰显了上海城市森林建设的生态效能。最后,建议将保护珍稀物种及其生境的理念融入全域土地综合整治工作,为指导大都市国土综合整治和生态保护修复工作提供新思路和新挑战。展开更多
测定了雷公藤总生物碱对小菜蛾和菜青虫的室内毒力,以及0.1%雷公藤生物碱乳油对两种害虫的田间防效。结果表明,雷公藤总生物碱对小菜蛾3龄幼虫48和72 h的LC50值分别为228.28和136.67 m g/L,对菜青虫5龄幼虫48和72 h的LC50值分别为307.61...测定了雷公藤总生物碱对小菜蛾和菜青虫的室内毒力,以及0.1%雷公藤生物碱乳油对两种害虫的田间防效。结果表明,雷公藤总生物碱对小菜蛾3龄幼虫48和72 h的LC50值分别为228.28和136.67 m g/L,对菜青虫5龄幼虫48和72 h的LC50值分别为307.61和238.18 m g/L;1.0%雷公藤生物碱乳油对小菜蛾的毒杀作用较强,其48和72 h的LC50值分别为69.62和20.35 m g/L,对菜青虫48和72 h的LC50值分别为93.18和44.62 m g/L。250倍稀释的雷公藤生物碱乳油(有效含量为40 m g/L)田间喷雾处理对小菜蛾和菜青虫均具有较好的防治效果,施药后7 d的防治效果分别为82.93%和82.71%,在本试验剂量范围内对作物安全。可见,雷公藤生物碱制品对两种蔬菜害虫控制效果显著。展开更多
The non alkaloid contents were extracted from the root bark of Tripterygium wilfordii Hook. The results of bioassy showed that the non alkaloid extracts has abviously insectidal activities to imported cabbage worm ( P...The non alkaloid contents were extracted from the root bark of Tripterygium wilfordii Hook. The results of bioassy showed that the non alkaloid extracts has abviously insectidal activities to imported cabbage worm ( Pieris rapae L.).LC 50 values of poisoning to the 5th instarts of Pieris rapae is 7.23 mg·L -1 . The values of medium antifeeding concentration (AFC 50 ) of the non alkaloid extracted against the 5th larval of Pieris rape is 11.34 mg·L -1 . Median narcosis dose (ND 50 ) is 15.54 μg/g.Median contact dose (LD 50 ) is 3.1079 μg/head. The non alkaloid extracts have no fumigant to insect. The main poisoning symptoms are that the tested insect showed paralysis and the epiderm of the larval turns black, the larval are dead at last.展开更多
文摘AISI 304L is an austenitic Chromium-Nickel stainless steel offering the optimum combination of corrosion resistance, strength and ductility. These attributes make it a favorite for many mechanical components. The paper focuses on developing mathematical models to predict grain size and hardness of pulsed current micro plasma arc welded AISI 304L joints. Four factors, five level, central composite rotatable design matrix is used to optimize the number of experiments. The mathematical models have been developed by Response Surface Method (RSM) and its adequacy is checked by Analysis of Variance (ANOVA) technique. By using the developed mathematical models, grain size and hardness of the weld joints can be predicted with 99% confidence level. The developed mathematical models have been optimized using Hooke and Jeeves algorithm to minimize grain size and maximize the hardness.
文摘上海作为我国最大的城市之一,人口密集,人类活动频繁,原生植被物种多样性受人为干扰严重。作为古老的孑遗植物,蕨类植物对生长和繁殖环境要求严格,能够灵敏地指示环境变化。为摸清上海市国土空间生态环境现状,调查团队在上海市全域土地综合整治项目区内展开长期定点监测,期间在奉贤区西渡街道辖区发现了上海蕨类植物新记录种——柄叶瓶尔小草(Ophioglossum petiolatum Hook.)。文章对新记录种的形态特征和发现生境进行描述,讨论了Flora of China与《云南植物志》对其形态描述的差异,认为《云南植物志》中的描述与原始发表文献和模式标本更为接近,即该种的重要特征为其不育叶的基部下延呈柄状。柄叶瓶尔小草在江浙沪地区亦属首次报道,此次发现扩大了该种向东和北的分布记录,对研究蕨类区系分布有推进作用;瓶尔小草属植物近年来在华东地区较为罕见,本次发现地位于上海市全域土地综合整治项目区内的生态公益林,彰显了上海城市森林建设的生态效能。最后,建议将保护珍稀物种及其生境的理念融入全域土地综合整治工作,为指导大都市国土综合整治和生态保护修复工作提供新思路和新挑战。
文摘测定了雷公藤总生物碱对小菜蛾和菜青虫的室内毒力,以及0.1%雷公藤生物碱乳油对两种害虫的田间防效。结果表明,雷公藤总生物碱对小菜蛾3龄幼虫48和72 h的LC50值分别为228.28和136.67 m g/L,对菜青虫5龄幼虫48和72 h的LC50值分别为307.61和238.18 m g/L;1.0%雷公藤生物碱乳油对小菜蛾的毒杀作用较强,其48和72 h的LC50值分别为69.62和20.35 m g/L,对菜青虫48和72 h的LC50值分别为93.18和44.62 m g/L。250倍稀释的雷公藤生物碱乳油(有效含量为40 m g/L)田间喷雾处理对小菜蛾和菜青虫均具有较好的防治效果,施药后7 d的防治效果分别为82.93%和82.71%,在本试验剂量范围内对作物安全。可见,雷公藤生物碱制品对两种蔬菜害虫控制效果显著。
文摘The non alkaloid contents were extracted from the root bark of Tripterygium wilfordii Hook. The results of bioassy showed that the non alkaloid extracts has abviously insectidal activities to imported cabbage worm ( Pieris rapae L.).LC 50 values of poisoning to the 5th instarts of Pieris rapae is 7.23 mg·L -1 . The values of medium antifeeding concentration (AFC 50 ) of the non alkaloid extracted against the 5th larval of Pieris rape is 11.34 mg·L -1 . Median narcosis dose (ND 50 ) is 15.54 μg/g.Median contact dose (LD 50 ) is 3.1079 μg/head. The non alkaloid extracts have no fumigant to insect. The main poisoning symptoms are that the tested insect showed paralysis and the epiderm of the larval turns black, the larval are dead at last.
