Copper metal is one important raw material of national economy, and its security is tightly linked with industrialization process. A comprehensive security evaluation index system, including three first class indicato...Copper metal is one important raw material of national economy, and its security is tightly linked with industrialization process. A comprehensive security evaluation index system, including three first class indicators, nine second class indicators and fourteen third class indicators, was constructed based on the pressure-state-response （PSR） model. And efficacy coeff^cient method was adopted in dimensionless treatment and entropy method was used to obtain the weight. Then, the data of China＇s copper from 1992 to 2011 were studied and collected. By processing these data, a comprehensive safety index of China＇s copper was got. The results showed that the comprehensive safety index of China＇s copper rose from its low point. The safety pressure state of China＇s copper was improved. The safety state of China＇s copper continued to be tight. The response state continued to rise. The overall situation of China＇s copper safety was improving, but still not optimistic.展开更多
Five Cu-ZSM-5 catalysts were obtained by treating Na-ZSM-5 （Si/Al ratio = 15） with aqueous solutions of differ- ent Cu precursors （CuCl2, Cu（NO3）2, CuSO4, Cu（CH3COO）2, and ammoniacal copper （II） complex ion）...Five Cu-ZSM-5 catalysts were obtained by treating Na-ZSM-5 （Si/Al ratio = 15） with aqueous solutions of differ- ent Cu precursors （CuCl2, Cu（NO3）2, CuSO4, Cu（CH3COO）2, and ammoniacal copper （II） complex ion）. After being pretreated in flowing He at 500 ℃ to form active Cu＋, these catalysts exhibited quite different activities in cata- lytic decomposition of N2O. CZM-AC（II） （prepared by ammoniacal copper （II） complex ion） with 9.4 wt% Cu con- tent was the most active among these Cu-ZSM-5 catalysts, achieving almost complete N2I conversion at 400 ℃. CZM-CA （prepared using Cu（ CH3COO）2 as the Cu precursor） with 2.8 wt% Cu content was the second most active catalyst among these Cu-ZSM-5 catalysts, achieving almost complete N2I conversion at 425 ℃. CZM-CC, CZM- CN, and CZM-CS prepared by using CuCl2, Cu（NO3）2, or CuSO4 as the Cu precursor with similar Cu contents （≈1.7 wt%） were the least active among these Cu-ZSM-5 catalysts, achieving ca. 90% N2O conversion at 500 ℃. XRD, ICP, SEM, TEM, EDX-mapping, and CO-IR experiments were conducted to characterize relevant samples. The superior activity of CZM-AC（II） can be attributed to the high contents of total Cu＋ and dimeric Cu＋ among these samples. The influence of co-fed O2 or H2O on the catalytic performance of typical samples was also studied.展开更多
Significant changes in the Raman spectrum of single-layer graphene grown on a copper film were observed after the spontaneous oxidation of the underlying substrate that occurred under ambient conditions. The frequenci...Significant changes in the Raman spectrum of single-layer graphene grown on a copper film were observed after the spontaneous oxidation of the underlying substrate that occurred under ambient conditions. The frequencies of the graphene G and 2D Raman modes were found to undergo red shifts, while the intensities of the two bands change by more than an order of magnitude. To understand the origin of these effects, we further characterized the samples by scanning tunneling microscopy （STM）, scanning tunneling spectroscopy （STS）, and atomic force microscopy （AFM）. The oxidation of the substrate produced an appreciable corrugation in the substrate without disrupting the crystalline order of the graphene overlayer and/or changing the carrier doping level. We explain the red shifts of the Raman frequencies in terms of tensile strain induced by corrugation of the graphene layer. The changes in Raman intensity with oxidation arise from the influence of the thin cuprous oxide film on the efficiency of light coupling with the graphene layer in the Raman scattering process.展开更多
基金Projects(13BGL105,13&ZD024) supported by the National Social Science Foundation of ChinaProject(2013ZK2003) supported by the Major Soft Program of Hunan Province,China
文摘Copper metal is one important raw material of national economy, and its security is tightly linked with industrialization process. A comprehensive security evaluation index system, including three first class indicators, nine second class indicators and fourteen third class indicators, was constructed based on the pressure-state-response （PSR） model. And efficacy coeff^cient method was adopted in dimensionless treatment and entropy method was used to obtain the weight. Then, the data of China＇s copper from 1992 to 2011 were studied and collected. By processing these data, a comprehensive safety index of China＇s copper was got. The results showed that the comprehensive safety index of China＇s copper rose from its low point. The safety pressure state of China＇s copper was improved. The safety state of China＇s copper continued to be tight. The response state continued to rise. The overall situation of China＇s copper safety was improving, but still not optimistic.
基金Supported by the National Natural Science Foundation of China(Grant No.21477022)
文摘Five Cu-ZSM-5 catalysts were obtained by treating Na-ZSM-5 （Si/Al ratio = 15） with aqueous solutions of differ- ent Cu precursors （CuCl2, Cu（NO3）2, CuSO4, Cu（CH3COO）2, and ammoniacal copper （II） complex ion）. After being pretreated in flowing He at 500 ℃ to form active Cu＋, these catalysts exhibited quite different activities in cata- lytic decomposition of N2O. CZM-AC（II） （prepared by ammoniacal copper （II） complex ion） with 9.4 wt% Cu con- tent was the most active among these Cu-ZSM-5 catalysts, achieving almost complete N2I conversion at 400 ℃. CZM-CA （prepared using Cu（ CH3COO）2 as the Cu precursor） with 2.8 wt% Cu content was the second most active catalyst among these Cu-ZSM-5 catalysts, achieving almost complete N2I conversion at 425 ℃. CZM-CC, CZM- CN, and CZM-CS prepared by using CuCl2, Cu（NO3）2, or CuSO4 as the Cu precursor with similar Cu contents （≈1.7 wt%） were the least active among these Cu-ZSM-5 catalysts, achieving ca. 90% N2O conversion at 500 ℃. XRD, ICP, SEM, TEM, EDX-mapping, and CO-IR experiments were conducted to characterize relevant samples. The superior activity of CZM-AC（II） can be attributed to the high contents of total Cu＋ and dimeric Cu＋ among these samples. The influence of co-fed O2 or H2O on the catalytic performance of typical samples was also studied.
文摘Significant changes in the Raman spectrum of single-layer graphene grown on a copper film were observed after the spontaneous oxidation of the underlying substrate that occurred under ambient conditions. The frequencies of the graphene G and 2D Raman modes were found to undergo red shifts, while the intensities of the two bands change by more than an order of magnitude. To understand the origin of these effects, we further characterized the samples by scanning tunneling microscopy （STM）, scanning tunneling spectroscopy （STS）, and atomic force microscopy （AFM）. The oxidation of the substrate produced an appreciable corrugation in the substrate without disrupting the crystalline order of the graphene overlayer and/or changing the carrier doping level. We explain the red shifts of the Raman frequencies in terms of tensile strain induced by corrugation of the graphene layer. The changes in Raman intensity with oxidation arise from the influence of the thin cuprous oxide film on the efficiency of light coupling with the graphene layer in the Raman scattering process.
