To obtain excellent magnetic properties of machinable REPM prepared by directional solidification (DS) technology, Space A, a composition area with theta=0 degrees similar to 5 degrees where easy axis is parallel to s...To obtain excellent magnetic properties of machinable REPM prepared by directional solidification (DS) technology, Space A, a composition area with theta=0 degrees similar to 5 degrees where easy axis is parallel to solidified direction of alloys, has been established in Zr-Sm-La-Co-Cu-Fe system. In 2/17+1/5+Co, and 2/17+1/5 region near Co phase of Space A, one obtains: V-f = 80.933 - 2.739Zr - 1.828Sm - 0.773Co - 0.147Cu + 0.415Fe + 0.218La Nonequilibrium solidification process of alloys in 2/17+1/5+Co region, is as follows: L-->Co, L-->2/17, L+2/17-->1/5 and L-->1/(5-x)+1/(5+x). The product of partially completed peritectic reaction, and 1/(5-x) and 1/(5+x) phases can all be transformed into a homogeneous 1/5 phase after solution treatment in 1413 K for 5 h. Containing 3 similar to 6% Co phase magnetically hardened by 0.5 similar to 2.5% V, the DS magnets have been achieved with both improved toughness and excellent coercive force of 520 kA/m.展开更多
The conductivity of phosphorus-doped hydrogenated nanocrystalline Si (nc-Si:P:H) films is 10(-1) similar to 10(1) Omega(-1).cm(-1), two order of magnitude higher than that of undoped hydrogenated nanocrystalline Si (n...The conductivity of phosphorus-doped hydrogenated nanocrystalline Si (nc-Si:P:H) films is 10(-1) similar to 10(1) Omega(-1).cm(-1), two order of magnitude higher than that of undoped hydrogenated nanocrystalline Si (nc-Si:H) film. A series of conductivity temperature dependence curves show that the kink point temperature almost existing in hydrogenated amorphous Si (a-Si:H) film disappears.展开更多
Precise evaluation of innerdiameter distribution of open carbon nanotubes (CNTs) is the basis of systematic investigation of physico-chemical processes occurring in nano-sized quasi-1-dimensional carbons. Due to the p...Precise evaluation of innerdiameter distribution of open carbon nanotubes (CNTs) is the basis of systematic investigation of physico-chemical processes occurring in nano-sized quasi-1-dimensional carbons. Due to the porosity characteristics and adsorption properties, this study evaluated the innerdiameter and its distribution of carbon nanotubes by analyses of nitrogen cryo-adsorption isotherms, and proved that the gas adsorption method is an effective method to characterize the inner cavity structure in comparison with that of electron microscopy observations and Raman measurements. The advantages of this method are as follows: Firstly, statistical information for innerdiameter distribution of open nanotubes can be obtained; Secondly, the method based on the adsorption process in inner cavities is of importance for investigation of other physico-chemical pro- cesses inside the cavities of carbon nanotubes. And finally, if combining with other characterization methods, complete structural information展开更多
文摘To obtain excellent magnetic properties of machinable REPM prepared by directional solidification (DS) technology, Space A, a composition area with theta=0 degrees similar to 5 degrees where easy axis is parallel to solidified direction of alloys, has been established in Zr-Sm-La-Co-Cu-Fe system. In 2/17+1/5+Co, and 2/17+1/5 region near Co phase of Space A, one obtains: V-f = 80.933 - 2.739Zr - 1.828Sm - 0.773Co - 0.147Cu + 0.415Fe + 0.218La Nonequilibrium solidification process of alloys in 2/17+1/5+Co region, is as follows: L-->Co, L-->2/17, L+2/17-->1/5 and L-->1/(5-x)+1/(5+x). The product of partially completed peritectic reaction, and 1/(5-x) and 1/(5+x) phases can all be transformed into a homogeneous 1/5 phase after solution treatment in 1413 K for 5 h. Containing 3 similar to 6% Co phase magnetically hardened by 0.5 similar to 2.5% V, the DS magnets have been achieved with both improved toughness and excellent coercive force of 520 kA/m.
文摘The conductivity of phosphorus-doped hydrogenated nanocrystalline Si (nc-Si:P:H) films is 10(-1) similar to 10(1) Omega(-1).cm(-1), two order of magnitude higher than that of undoped hydrogenated nanocrystalline Si (nc-Si:H) film. A series of conductivity temperature dependence curves show that the kink point temperature almost existing in hydrogenated amorphous Si (a-Si:H) film disappears.
基金This work was supported by the Special Funds for Major State Basic Research Projects of the Ministry of Science and Technology of China (Grant No. G2000026403) the National Natural Science Foundation of China (Grant Nos. 59902009 and 50025204) China
文摘Precise evaluation of innerdiameter distribution of open carbon nanotubes (CNTs) is the basis of systematic investigation of physico-chemical processes occurring in nano-sized quasi-1-dimensional carbons. Due to the porosity characteristics and adsorption properties, this study evaluated the innerdiameter and its distribution of carbon nanotubes by analyses of nitrogen cryo-adsorption isotherms, and proved that the gas adsorption method is an effective method to characterize the inner cavity structure in comparison with that of electron microscopy observations and Raman measurements. The advantages of this method are as follows: Firstly, statistical information for innerdiameter distribution of open nanotubes can be obtained; Secondly, the method based on the adsorption process in inner cavities is of importance for investigation of other physico-chemical pro- cesses inside the cavities of carbon nanotubes. And finally, if combining with other characterization methods, complete structural information
