The pure iron was melted and deoxidized by metallic Al and rare earth elements La, Ce and Y respectively at 1600℃ in a vertical resistance furnace. The morphology, chemical composition and size distribution of the in...The pure iron was melted and deoxidized by metallic Al and rare earth elements La, Ce and Y respectively at 1600℃ in a vertical resistance furnace. The morphology, chemical composition and size distribution of the inclusions in deoxidized liquid iron have been investigated by using of SEM and image-analysis techniques. The investigated results show that the deoxidation products in molten iron are complex inclusions of rare earth oxide or A12O3 combined with FeO finely distributed. The proper holding time and rapid cooling rate can make inclusions finer. La, Y and Al are more effective than Ce for obtaining finely distributed inclusions.展开更多
Aligned silicon dioxide nanotubes with diameter of 60-70 nm were synthesized inside the nanoholes of an anodic AI membrane (AAM) template by pressure impregnating the AAM pores with the SiO2 sol. The Si02 nanotubes wi...Aligned silicon dioxide nanotubes with diameter of 60-70 nm were synthesized inside the nanoholes of an anodic AI membrane (AAM) template by pressure impregnating the AAM pores with the SiO2 sol. The Si02 nanotubes with different wall thickness were produced by repeating the process. Using the second-order template of porous AAM with silicon dioxide nanotubes, it was fabricated the nanostructure of Fe nanowires encapsulated by SiO2 nanotubes by electrochemical deposition. Scanning electron microscope (SEM) and transmission electron microscope (TEM) observations show that the nanotubes and nanocables are compact, continuous and uniform. Selected area electron diffraction (SAED) pattern shows the Fe nanowire is a single crystal. The magnetic properties of these samples were checked by a vibrating sample magnetometer (VSM). The coercivities of the samples are greatly improved compared to the corresponding bulk materials.展开更多
A performance study of several CCD cameras of the Chinese Joint Laboratory of Optical Astronomy (CJLOA) is presented. The main results are: 1) We propose a modified classical method to analyse the linearity of CCD cam...A performance study of several CCD cameras of the Chinese Joint Laboratory of Optical Astronomy (CJLOA) is presented. The main results are: 1) We propose a modified classical method to analyse the linearity of CCD cameras. This method is more sensitive and accurate as well as more intuitive, especially in measuring around the 0.1%-0.2% range of nonlinearity. 2) To illustrate the advantage of the method, the linearity performance of the CCD cameras at CJLOA has been measured and analysed. 3) For the CCD systems tested, there is no unique formula to represent the correlation over the entire CCD frame between the deviation from linearity and the pixel value, i.e., different pixel has different correction even though their pixel values are the same. 4) For the BFOSC (BAO Faint Object Spectrograph Camera) Loral CCD camera and the Tek CCD camera at the 1.56-m reflector, blooming (bleeding) happens long before saturation, and we suspect whether it could have resulted from the charge transfer efficiency (CTE) not being high enough.展开更多
文摘The pure iron was melted and deoxidized by metallic Al and rare earth elements La, Ce and Y respectively at 1600℃ in a vertical resistance furnace. The morphology, chemical composition and size distribution of the inclusions in deoxidized liquid iron have been investigated by using of SEM and image-analysis techniques. The investigated results show that the deoxidation products in molten iron are complex inclusions of rare earth oxide or A12O3 combined with FeO finely distributed. The proper holding time and rapid cooling rate can make inclusions finer. La, Y and Al are more effective than Ce for obtaining finely distributed inclusions.
基金The authors were grateful to the National Natural Science Foundation of China(NSFC)for financial support(Grant No.50128202).
文摘Aligned silicon dioxide nanotubes with diameter of 60-70 nm were synthesized inside the nanoholes of an anodic AI membrane (AAM) template by pressure impregnating the AAM pores with the SiO2 sol. The Si02 nanotubes with different wall thickness were produced by repeating the process. Using the second-order template of porous AAM with silicon dioxide nanotubes, it was fabricated the nanostructure of Fe nanowires encapsulated by SiO2 nanotubes by electrochemical deposition. Scanning electron microscope (SEM) and transmission electron microscope (TEM) observations show that the nanotubes and nanocables are compact, continuous and uniform. Selected area electron diffraction (SAED) pattern shows the Fe nanowire is a single crystal. The magnetic properties of these samples were checked by a vibrating sample magnetometer (VSM). The coercivities of the samples are greatly improved compared to the corresponding bulk materials.
文摘A performance study of several CCD cameras of the Chinese Joint Laboratory of Optical Astronomy (CJLOA) is presented. The main results are: 1) We propose a modified classical method to analyse the linearity of CCD cameras. This method is more sensitive and accurate as well as more intuitive, especially in measuring around the 0.1%-0.2% range of nonlinearity. 2) To illustrate the advantage of the method, the linearity performance of the CCD cameras at CJLOA has been measured and analysed. 3) For the CCD systems tested, there is no unique formula to represent the correlation over the entire CCD frame between the deviation from linearity and the pixel value, i.e., different pixel has different correction even though their pixel values are the same. 4) For the BFOSC (BAO Faint Object Spectrograph Camera) Loral CCD camera and the Tek CCD camera at the 1.56-m reflector, blooming (bleeding) happens long before saturation, and we suspect whether it could have resulted from the charge transfer efficiency (CTE) not being high enough.
