为改善时间早熟收敛问题,提高机械臂的运行效率。针对给定约束条件,首先利用三次样条函数插值技术获得机械臂的关节轨迹曲线,然后建立目标函数,以最优时间为目标,利用多种群遗传算法（multiple population genetic algorithm,MPGA）来...为改善时间早熟收敛问题,提高机械臂的运行效率。针对给定约束条件,首先利用三次样条函数插值技术获得机械臂的关节轨迹曲线,然后建立目标函数,以最优时间为目标,利用多种群遗传算法（multiple population genetic algorithm,MPGA）来优化时间,实现机械臂以最快的速度运动到达目标位置。借助于六关节机械臂,该算法通过与简单遗传算法的对比分析可知最优时间由4.15 s缩减到到了4 s,运行时间、迭代次数和收敛率都得到了明显的升高,并且优化后的机械臂的位移、速度、加速度都是平滑稳定,没有明显的突变。由此可得该算法改善了时间早熟收敛问题并提高了运行效率,证明了提出的轨迹规划方法的有效性。展开更多
We fabricated the nanofiber composite membranes by impregnating Nafion into the modified polyvinylidene fluoride(PVDF) electrospinning nanofiber mat for proton exchange membrane fuel cells applications.The hydrophobic...We fabricated the nanofiber composite membranes by impregnating Nafion into the modified polyvinylidene fluoride(PVDF) electrospinning nanofiber mat for proton exchange membrane fuel cells applications.The hydrophobic PVDF nanofibers mat became to the hydrophilic state by alkali treatment for the full embedding of Nafion into the PVDF network.The fabricated composite membranes exhibit significantly enhanced thermal stabilities,swelling resistance,and observably improved mechanical property compared to the pristine Nafion membrane.When the content of PVDF nanofiber mat is 15.1wt% in the membrane,the proton conductivity of the nanofiber composite membrane is nearly equal to that of pristine Nafion membrane with the same condition.The experimental results show that the prepared composite membrane can be used as a promising polyelectrolyte membrane for fuel cell applications.展开更多
比较了OEKO-TEX STANDARD 100 2018版和2017版的差异,列出了新增的4种其他残余化学物、6种禁用染料和2类残余表面活性剂润湿剂,新版标准变更了婴幼儿用品的耐水色牢度,修改了附录6中的残余溶剂项目要求,并将铬(六价)、芳香胺和染料的检...比较了OEKO-TEX STANDARD 100 2018版和2017版的差异,列出了新增的4种其他残余化学物、6种禁用染料和2类残余表面活性剂润湿剂,新版标准变更了婴幼儿用品的耐水色牢度,修改了附录6中的残余溶剂项目要求,并将铬(六价)、芳香胺和染料的检测限值直接列于表格中。展开更多
Ball in cage structures of cobalt sulfide have been successfully prepared by a facile one-pot hydrothermal synthesis approach employing Co（NO3）2＇6H20 as the cobalt source and S=C（NH2）2 as the sulfur source. The e...Ball in cage structures of cobalt sulfide have been successfully prepared by a facile one-pot hydrothermal synthesis approach employing Co（NO3）2＇6H20 as the cobalt source and S=C（NH2）2 as the sulfur source. The effects of the reaction parameters （volume ratio of distilled water to ethanol, reaction time and reaction temperature） on the morphology and size of the CoS structures were investigated. The synthesized product was characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. It has been confirmed that the volume ratio of distilled water to ethanol played a key role in the formation of the ball in cage structures, and the formation mechanism of the CoS ball in cage structures was also proposed. The electrochemical capacitance performances of the CoS products were studied, and the CoS ball in cage structures show excellent energy storage characteristics.展开更多
基金Funded by the National Science Foundation of China(21673167)the Open Project Program of High-Tech Organic Fibers Key Laboratory of Sichuan Province。
文摘We fabricated the nanofiber composite membranes by impregnating Nafion into the modified polyvinylidene fluoride(PVDF) electrospinning nanofiber mat for proton exchange membrane fuel cells applications.The hydrophobic PVDF nanofibers mat became to the hydrophilic state by alkali treatment for the full embedding of Nafion into the PVDF network.The fabricated composite membranes exhibit significantly enhanced thermal stabilities,swelling resistance,and observably improved mechanical property compared to the pristine Nafion membrane.When the content of PVDF nanofiber mat is 15.1wt% in the membrane,the proton conductivity of the nanofiber composite membrane is nearly equal to that of pristine Nafion membrane with the same condition.The experimental results show that the prepared composite membrane can be used as a promising polyelectrolyte membrane for fuel cell applications.
基金supported by the National Natural Science Foundation of China (50972130, 21003035)Zhejiang Provincial Natural Science Foundation for Distinguished Young Scholars (LR12E02001)+3 种基金Science and Technology Department of Zhejiang Province Foundation (2012C23037)Qianjiang Talent Program of Zhejiang Province (QJD1002001)Zhejiang Environmental Protection Bureau Foundation (2011B19)the Special Funds for key innovation team of Zhejiang Province (2010R50017)
文摘Ball in cage structures of cobalt sulfide have been successfully prepared by a facile one-pot hydrothermal synthesis approach employing Co（NO3）2＇6H20 as the cobalt source and S=C（NH2）2 as the sulfur source. The effects of the reaction parameters （volume ratio of distilled water to ethanol, reaction time and reaction temperature） on the morphology and size of the CoS structures were investigated. The synthesized product was characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. It has been confirmed that the volume ratio of distilled water to ethanol played a key role in the formation of the ball in cage structures, and the formation mechanism of the CoS ball in cage structures was also proposed. The electrochemical capacitance performances of the CoS products were studied, and the CoS ball in cage structures show excellent energy storage characteristics.
