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间苯二酚-甲醛树脂凝胶对Co/SiO_2催化剂费-托性能的影响(英文) 被引量:2
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作者 陈亮 沈俭一 《催化学报》 SCIE EI CAS CSCD 北大核心 2012年第4期621-628,共8页
采用共沉淀法制备了高Co含量的Co/SiO2费托合成催化剂,并向其中添加一定含量的间苯二酚-甲醛树脂凝胶.结果表明,催化剂在393K干燥时,树脂会发生分解,因而仅有少量的含碳凝胶残留在催化剂中.然而,少量碳凝胶的存在显著增加了催化剂的还... 采用共沉淀法制备了高Co含量的Co/SiO2费托合成催化剂,并向其中添加一定含量的间苯二酚-甲醛树脂凝胶.结果表明,催化剂在393K干燥时,树脂会发生分解,因而仅有少量的含碳凝胶残留在催化剂中.然而,少量碳凝胶的存在显著增加了催化剂的还原度和金属钴的分散度,致使催化剂表面产生更多的活性金属Co,同时,催化剂的孔径也有所增大,因此Co/SiO2催化剂具有更高的反应活性及高碳烃选择性.其中80%Co/SiO2-C催化剂活性及高碳烃的选择性与我们前期报道的一种高活性的80%Co-8%ZrO/SiO催化剂相近. 展开更多
关键词 高负载钴 二氧化硅 间苯二酚-甲醛树脂 费-托合成 微量吸附量热 活性位数目
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Effect of Correlations on the Exponents for the Power-Law Distributions in Self-Organized Criticality
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作者 邓永菊 郑华 杨纯斌 《Communications in Theoretical Physics》 SCIE CAS CSCD 2012年第8期313-316,共4页
The origin of power-law distributions in self-organized criticality is investigated by treating the variation of the number of active sites in the system as a stochastic process. An avalanche is mapped to a first-retu... The origin of power-law distributions in self-organized criticality is investigated by treating the variation of the number of active sites in the system as a stochastic process. An avalanche is mapped to a first-return random-walk process in a one-dimensional lattice. In order to understand the reason of variant exponents for the power-law distributions in different self-organized critical systems, we introduce the correlations among evolution steps. Power-law distributions of the lifetime and spatial size are found when the random walk is unbiased with equal probability to move in opposite directions. It is found that the longer the correlation length, the smaller values of the exponents for the power-law distributions. 展开更多
关键词 power-law distribution CORRELATION self-organized criticality RANDOM-WALK
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