期刊文献+
共找到5篇文章
< 1 >
每页显示 20 50 100
Effect of ZnO on the performance of Ag/SiO_2 catalyst for the vapor-phase synthesis of 3-methylindole 被引量:2
1
作者 Yang Hu Wenhui Lu Dongyan Liu Jing Liu Lei Shi Qi Sun 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2009年第4期445-448,共4页
The vapor-phase synthesis of 3-methylindole over Ag/SiO2 doped with ZnO was investigated. The catalysts were characterized by XRD, H2- TPR, NH3-TPD and TG techniques. The results indicated that ZnO promoter greatly en... The vapor-phase synthesis of 3-methylindole over Ag/SiO2 doped with ZnO was investigated. The catalysts were characterized by XRD, H2- TPR, NH3-TPD and TG techniques. The results indicated that ZnO promoter greatly enhanced the initial activity of the catalyst but disfavored its stability. H2-TPR and XRD results showed that the reduction peak of Ag2O shifted to higher temperature and the intensity of silver diffraction peaks was much weaker after the addition of ZnO promoter to Ag/SiO2. This indicated that there existed the interaction between Ag2O and SiO2-ZnO which promoted the silver particles dispersing on the support and inhibited the sintering of silver during the reaction. NH3-TPD and TG results revealed that the acid amounts of the catalyst and coking increased after adding ZnO to Ag/SiO2, which resulted in the deactivation of Ag/SiO2-ZnO catalyst rapidly. 展开更多
关键词 ZNO Ag/SiO2 3-methylindole initial activity SELECTIVITY stability
下载PDF
Initial Activation of Hydrogen-Storage Alloy Electrode by Chemical Modification 被引量:1
2
作者 卢世刚 李群 +3 位作者 路春 刘庆国 胡蓉晖 杨汉西 《Journal of Rare Earths》 SCIE EI CAS CSCD 1998年第4期68-71,共4页
The hydrogen storage alloy electrode of Mm(NiCoMnAl) 5 was activated by etching the alloy in a hot concentrated KOH solution. The electrochemical measurement demonstrates that the modified alloy electrode can reach ... The hydrogen storage alloy electrode of Mm(NiCoMnAl) 5 was activated by etching the alloy in a hot concentrated KOH solution. The electrochemical measurement demonstrates that the modified alloy electrode can reach its stable capacity at the first charge/discharge cycle and also shows low overpotential, indicating full activation of the etched alloy material. It was found from ICP, SEM and EDAX analyses that the activation process leads to surface modification by reconstructing of a new electroactive surface. 展开更多
关键词 Rare earths Hydrogen storage alloy Initial activation Chemical modification
下载PDF
National Resources Conservation Activities Initiated in DaQing
3
《China Standardization》 2006年第4期11-,共1页
  On May 20, 2006, General Administration of Quality Sup ervision,Inspection and Quarantine of the P.R.China conducted startup ceremony of "Initiating Resources Conservation Service" to coordinate the acti...   On May 20, 2006, General Administration of Quality Sup ervision,Inspection and Quarantine of the P.R.China conducted startup ceremony of "Initiating Resources Conservation Service" to coordinate the activities of propaganda for the seventh World Metrology Day.…… 展开更多
关键词 World In National Resources Conservation Activities Initiated in DaQing
下载PDF
Effect of actuating frequency on plasma assisted detonation initiation
4
作者 周思引 车学科 +1 位作者 王迪 聂万胜 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第2期468-475,共8页
Aiming at studying the influence of actuating frequency on plasma assisted detonation initiation by alternating current dielectric barrier discharge, a loosely coupled method is used to simulate the detonation initiat... Aiming at studying the influence of actuating frequency on plasma assisted detonation initiation by alternating current dielectric barrier discharge, a loosely coupled method is used to simulate the detonation initiation process of a hydrogenoxygen mixture in a detonation tube at different actuating frequencies. Both the discharge products and the detonation forming process which is assisted by the plasma are analyzed. It is found that the patterns of the temporal and spatial distributions of discharge products in one cycle are not changed by the actuating frequency. However, the concentration of every species decreases as the actuating frequency rises, and atom O is the most sensitive to this variation, which is related to the decrease of discharge power. With respect to the reaction flow of the detonation tube, the deflagration-todetonation transition(DDT) time and distance both increase as the actuating frequency rises, but the degree of effect on DDT development during flow field evolution is erratic. Generally, the actuating frequency affects none of the amplitude value of the pressure, temperature, species concentration of the flow field, and the combustion degree within the reaction zone. 展开更多
关键词 alternating current dielectric barrier discharge plasma assisted detonation initiation actuating frequency deflagration to detonation active particles
下载PDF
The Association Between H3K4me3 and Antisense Transcription 被引量:1
5
作者 Peng Cui Wanfei Liu +8 位作者 Yuhui Zhao Qiang Lin Feng Ding Chengqi Xin Jianing Geng Shuhui Song Fanglin Sun Songnian Hu Jun Yu 《Genomics, Proteomics & Bioinformatics》 CAS CSCD 2012年第2期74-81,共8页
Histone H3 lysine 4 trimethylation (H3K4me3) is well known to occur in the promoter region of genes for transcription activation. How- ever, when investigating the H3K4me3 profiles in the mouse cerebrum and testis, ... Histone H3 lysine 4 trimethylation (H3K4me3) is well known to occur in the promoter region of genes for transcription activation. How- ever, when investigating the H3K4me3 profiles in the mouse cerebrum and testis, we discovered that H3K4me3 also has a significant enrichment at the 3' end of actively transcribed (sense) genes, named as 3'-H3K4me3. 3'-H3K4me3 is associated with ~15% of pro- tein-coding genes in both tissues. In addition, we examined the transcriptional initiation signals including RNA polymerase II (RNAPII) binding sites and Y-CAGE-tag that marks transcriptional start sites. Interestingly, we found that 3'-H3K4me3 is associated with the ini- tiation of antisense transcription. Furthermore, 3'-H3K4me3 modification levels correlate positively with the antisense expression levels of the associated sense genes, implying that 3'-H3K4me3 is involved in the activation of antisense transcription. Taken together, our findings suggest that H3K4me3 may be involved in the regulation of antisense transcription that initiates from the 3' end of sense genes. In addition, a positive correlation was also observed between the expression of antisense and the associated sense genes with 3'-H3K4me3 modification. More importantly, we observed the 3'-H3K4me3 enrichment among genes in human, fruitfly and Arabidopsis, and found that the sequences of 3'-H3K4me3-marked regions are highly conserved and essentially indistinguishable from known promoters in ver- tebrate. Therefore, we speculate that these 3'-H3K4me3-marked regions may serve as potential promoters for antisense transcription and 3'-H3K4me3 appear to be a universal epigenetic feature in eukaryotes. Our results provide a novel insight into the epigenetic roles of H3K4me3 and the regulatory mechanism of antisense transcription. 展开更多
关键词 Antisense initiation and activation Antisense transcription H3K4me3
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部