苯胺基萘醌镍催化剂(Cat.1:4-甲基-2,6-双二苯甲基苯胺萘醌镍配合物、Cat.2:2,6-二异丙基苯胺萘醌镍配合物)可用于乙烯聚合,产物的形态难以控制,易黏釜,限制其工业化应用,因此对该催化剂进行负载化研究,通过将干燥的改性甲基铝氧烷(dMM...苯胺基萘醌镍催化剂(Cat.1:4-甲基-2,6-双二苯甲基苯胺萘醌镍配合物、Cat.2:2,6-二异丙基苯胺萘醌镍配合物)可用于乙烯聚合,产物的形态难以控制,易黏釜,限制其工业化应用,因此对该催化剂进行负载化研究,通过将干燥的改性甲基铝氧烷(dMMAO)和一氯二乙基铝(Et_2AlCl)负载于球形纳米级二氧化硅表面,从而使催化剂非均相化。Cat.1-MMAO/SiO_2这类负载型催化剂能引发乙烯均聚,活性高和热稳定性好,在60℃时活性最高,在100℃高温下依旧保持较高的活性(3 600 kg polymer/(mol Ni·h))。随着聚合温度的升高,所得聚乙烯的分子量降低,当反应温度为40℃时,分子量最高(69.4×10~4g/mol),且分子量分布为1.7。该催化体系不仅保留了均相体系活性高稳定性好的特点,还能制备出球形聚合物,具有良好的工业应用前景。展开更多
Fe46Co44B10/SiO2 nano-multilayers were synthesized by radio frequency magnetron sputtering. The thickness of individual layer was designed and controlled in nano-meter. The effect of thickness of ferromagnetic layer, ...Fe46Co44B10/SiO2 nano-multilayers were synthesized by radio frequency magnetron sputtering. The thickness of individual layer was designed and controlled in nano-meter. The effect of thickness of ferromagnetic layer, insulative layer or the total number of layers on the intrinsic characteristics and microwave permeability were investigated respectively. The results show that, saturation magnetization changes obviously with different thicknesses of ferromagnetic layer or insulative layer, but coercivity changes little and remains small. When the thickness of ferromagnetic layer and insulative layer keeps 1.5 and 1.3 nm respectively and the number of the total layers increases from 10 to 90, coercivity reduces and resistivity of the films improves from 0.25 to 2.22 π·m. The resonant frequency locates at the point higher than 2 GHz and the imaginary part of complex permeability at 2 GHz is larger than 150. These multilayer films can be applied in the field of micromagnetic devices or anti-interference of electromagnetic wave.展开更多
文摘苯胺基萘醌镍催化剂(Cat.1:4-甲基-2,6-双二苯甲基苯胺萘醌镍配合物、Cat.2:2,6-二异丙基苯胺萘醌镍配合物)可用于乙烯聚合,产物的形态难以控制,易黏釜,限制其工业化应用,因此对该催化剂进行负载化研究,通过将干燥的改性甲基铝氧烷(dMMAO)和一氯二乙基铝(Et_2AlCl)负载于球形纳米级二氧化硅表面,从而使催化剂非均相化。Cat.1-MMAO/SiO_2这类负载型催化剂能引发乙烯均聚,活性高和热稳定性好,在60℃时活性最高,在100℃高温下依旧保持较高的活性(3 600 kg polymer/(mol Ni·h))。随着聚合温度的升高,所得聚乙烯的分子量降低,当反应温度为40℃时,分子量最高(69.4×10~4g/mol),且分子量分布为1.7。该催化体系不仅保留了均相体系活性高稳定性好的特点,还能制备出球形聚合物,具有良好的工业应用前景。
基金Project(60771028) supported by the National Natural Science Foundation of ChinaProject(20091208) supported by the Postdoctoral Foundation of Central South UniversityProject(PM200815) supported by State Key Laboratory of Powder Metallurgy
文摘Fe46Co44B10/SiO2 nano-multilayers were synthesized by radio frequency magnetron sputtering. The thickness of individual layer was designed and controlled in nano-meter. The effect of thickness of ferromagnetic layer, insulative layer or the total number of layers on the intrinsic characteristics and microwave permeability were investigated respectively. The results show that, saturation magnetization changes obviously with different thicknesses of ferromagnetic layer or insulative layer, but coercivity changes little and remains small. When the thickness of ferromagnetic layer and insulative layer keeps 1.5 and 1.3 nm respectively and the number of the total layers increases from 10 to 90, coercivity reduces and resistivity of the films improves from 0.25 to 2.22 π·m. The resonant frequency locates at the point higher than 2 GHz and the imaginary part of complex permeability at 2 GHz is larger than 150. These multilayer films can be applied in the field of micromagnetic devices or anti-interference of electromagnetic wave.
