Using non-noble metal catalysts to chemoselectively reduce the 3-nitrostyrene into 3-vinylaniline is extremely attractive due to the importantapplications of aromatic amines.However,the separation and recycle of catal...Using non-noble metal catalysts to chemoselectively reduce the 3-nitrostyrene into 3-vinylaniline is extremely attractive due to the importantapplications of aromatic amines.However,the separation and recycle of catalytic particles to sustainably catalyze are still challenging on accountof their small size.In this communication,we report a novel magnetically recyclable catalyst of Sm2Co17/Cu to chemoselectively reduce3-nitrostyrene into 3-vinylaniline by activating ammonia borane(AB)to yield hydrogen.The Sm2Co17/Cu,composited of 180 nm Sm2Co17nano magnet and 10 nm Cu catalyst nano particles,shows a high conversi on(98%)and a high selectivity(99%)for 3-nitrostyrene under ultrasonic concussion.More importantly,they are easily collected by self-separation method without any magnetic field.As a consequenee,the excellent recyclable feature is acquired even underwent 10 cycles.Our approach provides a green strategy to synthesize magneticallyrecyclable catalysts.展开更多
Influence of Zr contents on high-temperature magnetic performance of Sm(CoFeCuZr)(x=0.025,0.03,0.035,0.04) magnets were investigated.As x increases from 0.025 to 0.04,the temperature coefficient of intrinsic coercivit...Influence of Zr contents on high-temperature magnetic performance of Sm(CoFeCuZr)(x=0.025,0.03,0.035,0.04) magnets were investigated.As x increases from 0.025 to 0.04,the temperature coefficient of intrinsic coercivity(H) is optimized from-0.1673% K^(-1)to-0.1382% K^(-1)and the Hat 773 K gradually increases from 556.32 kA m^(-1)to 667 kA m^(-1).The microstructure and microchemistry of different Zr-content magnets were revealed by a transmission electron microscope equipped with EDS.The increasing Zr content induces that the average size of cells decreases from ~76 nm to ~56 nm and the weight fraction of 1:5 H cell boundary phase increases from ~25% to ~37% as well,resulting decreasing of the average Cu content at cell boundaries from 13.59 at% to ~8.52 at%.It is found that the Cu-lean characteristic at cell boundary phase is the reason that gives rise to higher magnetic properties at elevated temperatures for x=0.04 magnet.展开更多
对磁路设计人员来说 ,精确知道不同种类磁体在不同温度范围内的磁性能随温度的变化情况是非常有用的。本文对Alnico、Sm2 Co17、普通Nd Fe B、低温度系数Nd Fe B四种磁体的可逆磁通在室温～ 12 0℃温度区间内的变化情况及其不同温度区...对磁路设计人员来说 ,精确知道不同种类磁体在不同温度范围内的磁性能随温度的变化情况是非常有用的。本文对Alnico、Sm2 Co17、普通Nd Fe B、低温度系数Nd Fe B四种磁体的可逆磁通在室温～ 12 0℃温度区间内的变化情况及其不同温度区间的平均温度系数进行了详细测量。得到了一些对磁路设计人员较有用的结果。展开更多
利用表面活性剂辅助高能球磨(SA-HEBM)分别制备了高性能的各向异性Sm2Co17纳米永磁粉末材料,然后对球磨产物进行超声波分散清洗。利用高速离心技术进行纳米颗粒分级,获得颗粒尺寸分布狭窄的纳米永磁颗粒,对所得粉末进行适当的快速热处...利用表面活性剂辅助高能球磨(SA-HEBM)分别制备了高性能的各向异性Sm2Co17纳米永磁粉末材料,然后对球磨产物进行超声波分散清洗。利用高速离心技术进行纳米颗粒分级,获得颗粒尺寸分布狭窄的纳米永磁颗粒,对所得粉末进行适当的快速热处理。分别采用扫描电镜、X射线衍射和振动样品磁强计分析、测试样品的显微形貌、相结构和室温磁性能。结果表明,粉末的厚度在80 nm左右,长度为亚微米级,具有高比表面积、强形状各向异性与磁各向异性;经过磁场取向后,Sm2Co17的易磁化轴和难磁化轴方向的室温矫顽力分别达到612.9 k A/m(7.7 k Oe)和278.6 k A/m(3.5 k Oe);表面活性剂在球磨过程中起到了重要作用。展开更多
基金The work was supported by the National Natural Science Foundation of China(Nos.51701109 and 51806115)Natural Science Foundation of Beijing Municipality,China(No.2192007)+3 种基金the China Postdoctoral Science Foundation(No.2018M641132)International S&T Cooperation Program of China(No.2015DFG52020),Key Program of National Natural Science Foundation of China(51331003)Program of Disciplines Construction in Beijing(No.PXM2019_014204_500031).
文摘Using non-noble metal catalysts to chemoselectively reduce the 3-nitrostyrene into 3-vinylaniline is extremely attractive due to the importantapplications of aromatic amines.However,the separation and recycle of catalytic particles to sustainably catalyze are still challenging on accountof their small size.In this communication,we report a novel magnetically recyclable catalyst of Sm2Co17/Cu to chemoselectively reduce3-nitrostyrene into 3-vinylaniline by activating ammonia borane(AB)to yield hydrogen.The Sm2Co17/Cu,composited of 180 nm Sm2Co17nano magnet and 10 nm Cu catalyst nano particles,shows a high conversi on(98%)and a high selectivity(99%)for 3-nitrostyrene under ultrasonic concussion.More importantly,they are easily collected by self-separation method without any magnetic field.As a consequenee,the excellent recyclable feature is acquired even underwent 10 cycles.Our approach provides a green strategy to synthesize magneticallyrecyclable catalysts.
基金partially supported by the National Natural Science Foundation of China (No. 51871063)the Key Technology Research and Development Program of Shandong (No. 2019JZZY020210)。
文摘Influence of Zr contents on high-temperature magnetic performance of Sm(CoFeCuZr)(x=0.025,0.03,0.035,0.04) magnets were investigated.As x increases from 0.025 to 0.04,the temperature coefficient of intrinsic coercivity(H) is optimized from-0.1673% K^(-1)to-0.1382% K^(-1)and the Hat 773 K gradually increases from 556.32 kA m^(-1)to 667 kA m^(-1).The microstructure and microchemistry of different Zr-content magnets were revealed by a transmission electron microscope equipped with EDS.The increasing Zr content induces that the average size of cells decreases from ~76 nm to ~56 nm and the weight fraction of 1:5 H cell boundary phase increases from ~25% to ~37% as well,resulting decreasing of the average Cu content at cell boundaries from 13.59 at% to ~8.52 at%.It is found that the Cu-lean characteristic at cell boundary phase is the reason that gives rise to higher magnetic properties at elevated temperatures for x=0.04 magnet.
文摘对磁路设计人员来说 ,精确知道不同种类磁体在不同温度范围内的磁性能随温度的变化情况是非常有用的。本文对Alnico、Sm2 Co17、普通Nd Fe B、低温度系数Nd Fe B四种磁体的可逆磁通在室温～ 12 0℃温度区间内的变化情况及其不同温度区间的平均温度系数进行了详细测量。得到了一些对磁路设计人员较有用的结果。
文摘利用表面活性剂辅助高能球磨(SA-HEBM)分别制备了高性能的各向异性Sm2Co17纳米永磁粉末材料,然后对球磨产物进行超声波分散清洗。利用高速离心技术进行纳米颗粒分级,获得颗粒尺寸分布狭窄的纳米永磁颗粒,对所得粉末进行适当的快速热处理。分别采用扫描电镜、X射线衍射和振动样品磁强计分析、测试样品的显微形貌、相结构和室温磁性能。结果表明,粉末的厚度在80 nm左右,长度为亚微米级,具有高比表面积、强形状各向异性与磁各向异性;经过磁场取向后,Sm2Co17的易磁化轴和难磁化轴方向的室温矫顽力分别达到612.9 k A/m(7.7 k Oe)和278.6 k A/m(3.5 k Oe);表面活性剂在球磨过程中起到了重要作用。
