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Effects of Calcination Temperature on the Acidity and Catalytic Performances of HZSM-5 Zeolite Catalysts for the Catalytic Cracking of n-Butane 下载免费PDF全文
The acidic modulations of a series of HZSM-5 catalysts were successfully made by calcination at different treatment temperatures, i.e. 500, 600, 650, 700 and 800 ℃, respectively. The results indicated that the total acid amounts, their density and the amount of B-type acid of HZSM-5 catalysts rapidly decreased, while the amounts of L-type acid had almost no change and thus the ratio of L/B was obviously enhanced with the increase of calcination temperature (excluding 800 ℃). The catalytic performances of modified HZSM-5 catalysts for the cracking of n-butane were also investigated. The main properties of these catalysts were characterized by means of XRD, N2 adsorption at low temperature, NH3-TPD, FTIR of pyridine adsorption and BET surface area measurements. The results showed that HZSM-5 zeolite pretreated at 800 ℃ had very low catalytic activity for n-butane cracking. In the calcination temperature range of 500-700 ℃, the total selectivity to olefins, propylene and butene were increased with the increase of calcination temperature, while, the selectivity for arene decreased with the calcination temperature.The HZSM-5 zeolite calcined at 700 ℃ produced light olefins with high yield, at the reaction temperature of 650 ℃ the yields of total olefins and ethylene were 52.8% and 29.4%, respectively. Besides, the more important role is that high calcination temperature treatment improved the duration stability of HZSM-5zeolites. The effect of calcination temperature on the physico-chemical properties and catalytic performance of HZSM-5 for cracking of n-butane was explored. It was found that the calcination temperature had large effects on the surface area, crystallinity and acid properties of HZSM-5 catalyst, which further affected the catalytic performance for n-butane cracking. 相似文献
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§1Introductionandstatementofresult DenotebySn-1theunitsphereinRn(n≥2)equippedwiththenormalizedLebesgue measuredx′=dσ(x′).LetΩ∈L1(Sn-1)behomogeneousofdegreezeroandsatisfy∫Sn-1Ω(x′)dx′=0.(1.1)Then-dimensionalMarcinkiewiczintegralcorrespondingtotheLittlewood-Paleyg-functionintroducedbyStein[1]isdefinedbyμΩ(f)(x)=∫∞0|FΩ,t(f)(x)|2dtt31/2,where FΩ,t(f)(x)=∫|x-y|≤tΩ(x-y)|x-y|n-1f(y)dy.In1958,Stein[1]provedthatifΩ∈Lipγ(Sn-1)(0<γ≤1),thenμΩisoftype(p,p)for1
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利用高分子支撑法将气相沉积(CVD)石墨烯从铜基底上转移到聚对苯二甲酸乙二醇酯(PET)基底上,制备出石墨烯平面电极(GPE), 通过循环伏安法将铁氰化钴(CoHCF)纳米颗沉积到GPE上,得到铁氰化钴修饰石墨烯平面电极(CoHCF/GPE).研究表明,此电极对过氧化氢具有良好的传感作用,从而构建一种新型无酶过氧化氢传感器.此传感器在过氧化氢浓度为5.0-1200 μmol/L范围内,响应电流与浓度呈现良好的线性关系,检出限为7.1 nmol/L (S/N=3),响应时间约为2 s,具有稳定性好、抗干扰能力强、制备简单等优点. 相似文献
4.
一类带有变量核的积分算子在Herz型Hardy空间的有界性 总被引:3,自引:0,他引:3
本文研究了带有变量核的奇异积分与分数次积分算子.当核函数满足一类Dini型条件时,证明了这类算子从Herz型Hardy空间到Herz空间的有界性. 相似文献
5.
给定一个扩张矩阵A,得到了某些伴随于A的各向异性Hardy空间Hp(Rn)的分子特征刻画.作为其应用,还研究了与A相关的Calderón-Zygmund奇异积分算子和分数次积分算子在各向异性Hardy空间的有界性. 相似文献
6.
本文讨论了具有齐性核的Marcinkiewicz积分μΩ在Herz型Hardy空间的有界性,证明了μΩ是从HKqα,p(Rn)到Kqα,p(Rn)有界的. 相似文献
7.
In this paper,the L2-boundedness of a class of parametric Marcinkiewicz integral μρΩ,h with kernel function Ω in Bq0.0 (Sn-1) for some q> 1,and the radial function h (x)∈ l∞ (Ls) (R+) for 1<s≤∞ are given. The Lp(Rn) (2≤p<∞) boundedness of μ*Ω,ph,λ and μρΩ,h,s with Ω in Bq0,0(Sn-1) and h(|x|)∈l∞(Ls)(R+) in application are obtained. Here μ*Ω,p h,λ and μpΩ,h,s are parametric Marcinkiewicz integrals corresponding to the Littlewood-Paley gλ* function and the Lusin area function S,respectively. 相似文献
8.
讨论了θ-型奇异积分算子交换子在Hardy空间的加权有界性. 相似文献
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10.
Marcinkiewicz积分交换子在Herz型空间中的弱型估计 总被引:1,自引:0,他引:1
用μΩ表示Marcinkiewicz积分,μΩ,b表示μΩ与函数b∈BMO(R~n)生成的交换子.本文证明了交换子μΩ,b是从Herz型Hardy空间H■_q~(n(1-(1/q)),p)(R~n)到弱Herz空间W■_q~(n(1-(1/q)),p)(R~n)有界的,其中0<p≤1,1<q<∞. 相似文献