金属基体上铝溶胶涂层的制备

 以拟薄水铝石为原料,采用HNO3胶溶法制备了铝溶胶,研究了制备条件对胶体性质的影响. 结果表明,拟薄水铝石的含量和HNO3的加入量是影响胶体粒度大小、粒径分布以及胶体稳定性的重要因素. 当拟薄水铝石的含量为4.5%~5.5%、酸加入量为［H+］/［AlOOH］=0.08~0.1(摩尔比)时,可以得到颗粒度小(平均粒径≤19.3 nm),粒径分布范围窄(4.1~53 nm)和稳定性好的胶体溶液. 以该胶体为过渡涂层涂覆在金属基体上. 在能形成稳定胶体的前提下,酸度相同时,胶体的浓度越大,粘度越大,涂覆到基体上的量就越多; 但是过渡涂层的牢固度似乎与胶体的浓度关系不大. 金属基体的前处理条件也是一个重要的因素,它不仅影响过渡层的涂覆量,也影响涂层的牢固度.     

红外导数光谱鉴定铁系复合氧化物中的γ-Fe_(2)O_3

用于丁烯氧化脱氢的铁系复合氧化物催化剂具有复杂的相组成，可能存在着。Fe。O。、1贝。0。、Fe。0。、铁酸盐尖晶石相及尖晶石相之间形成的固溶体，这些相的鉴定对于弄清活性位／相的结构具有本质意义．由于缺乏有效的相结构表征手段，导致对于活性位／相的结构和上述各相所起的作用的观，入歧异．Misono山曾测出7－Fe。O。具有较高的活性，故认为它是该系催化剂的活性相，但XRD难以把7－Fe。O。与其它尖晶石相区分开，因而无法确认它在催化剂中是否存在及起何作用．Gillot门提出了可用红外光谱鉴定了一FeZO。：1－Fe。O。在600～…     

一类弱整体维数为2的局部环上的Bass-Quillen问题Ⅱ

设R是U2环,即(R,m)是局部GCD整环,且存在u∈m-m2,使得R/(u)是赋值环,且Ru是Bézout整环.本文证明了若R是带有正规元素为u的U2环,且dim(R/(u))=1,则每个有限生成投射R[X1,...,Xn]模是自由模.由此得到了若R是广义伞环,则每个有限生成投射R[X1,...,Xn]模是自由模.     

二异丙苯和苯烷基转移反应中Y型沸石催化剂的研究

采用水热处理与离子交换结合的方法对ＮａＹ沸石进行了改性，ＸＲＤ、ＸＰＳ及孔结构测试结果表明，ＮａＹ沸石经水热处理和离子交换改性制得的Ｙ沸石催化剂的晶体晶型未发生变化；处理温度对催化剂的相对结晶度、孔结构及比表面积有很大影响；水热处理可以使微孔孔口啼生缺陷或破裂；在一定温度下，催化剂能够形成二次孔；过高的处理温度将导致催化忆结构的崩坍，Ｙ沸石催化剂存在铝富集在表面的现象，采用左外光谱及哟啶，２，６－     

一类弱整体维数为2的局部环上的Bass-Quillen问题II

设R是U2环,即(R,m)是局部GCD整环,且存在u∈m-m2,使得R/(u)是赋值环,且Ru是Bézout整环.本文证明了若R是带有正规元素为u的U2环,且dim(R/(u))=1,则每个有限生成投射R[X1,...,Xn]模是自由模.由此得到了若R是广义伞环,则每个有限生成投射R[X1,...,Xn]模是自由模.     

红外导数光谱鉴定铁系复合氧化物中γ-Fe2O3

It is well known that γ-Fe_2O_3 is a very active and selective catalyst for okidative dehydrogenation ofbutene to butadiene. It is hard, however, to distingulsh between ferrite spinels and therefore to identify its existence in ferrite-ferric oxide catalysts using XRD. On the IR spectra γ-Fe_2O_3 has characteristic bands in the range of 600~800 cm~(-1), which do not exist for α-Fe_2O_3, Fe3O4, ZnFe_2O_4 and MgFe_2O_4. But these bands are too weak to deterAnne for the small amount of γ-Fe_2O_3, e g. less than 30% (mass fraction), in catalysts.
Usually using second derivative IR spectra can increase the analytical sensitivity substantially. The mechanical mixtures of γ-Fe_2O_3 and MgFe_2O_4 in different ratio were prepared and their second derivative IR spectra were taken. It was found that the bands 730 and 695 cm~(-1) were characteristic of γ-Fe_2O_3 and their intensities increased with the content of γ-Fe_2O_3 in the mixtures. A staight line with R=0.994 can describe the relation between γ-Fe_2O_3 content and the peak area of band 695 cm~(-1). The lowest detectable content of γ-Fe_2O_3 is about 1% (mass fraction). The existence of γ-Fe_2O_3 in the used B-02 comercial catalyst was identified by this method.