Role of Cao

Figure 4 shows that activities of several kinds of iron oxide based catalysts. A Fe/Ca/Al oxides catalyst exhibited the best performance among the catalysts tested. Fe/Ca/Al and Fe/Al oxides catalysts were highly active, whereas Fe/Ca and Ca/Al oxides catalyst were extremely low in activity. The selectivities of Fe/Al oxides and Fe/Ca/Al oxides catalysts were almost the same (97% at 5.25 h), and the main by-products were benzene and toluene. Therefore the addition of an optimum amount of CaO to Fe/Al based catalyst could suppress the deactivation of the catalyst during long term reaction. Further experiment are under achievement to elucidate precisely the role of CaO. 

The role of CaO as a catalyst for the steam-char reaction can be inferred from the results obtained during mixed CO2-H2O gasification (figures 3 and 4). In many respects it is desirable to prevent the decomposition of CaCOj to CaO because of the high endothermic heats of reaction associated with this reaction. However, as we have shown, the steam gasification of oil shale char is about ten times slower when CaO is not present. A better evaluation of the importance of CaO requires a knowledge of the dependence of the reaction rate on the quantity of CaO present. 

AI2O3 is the component having a strong impact on the increase of hydraulic activity, as one can include from the other reports [36, 37], The role of MgO content up to 11 % is the same as the role of CaO. MnO has an unfavorable effect on the... 

Min B-K, Choi S-D (2004) Role of CaO as crystallite growth inhibitor in SnO. Sens Actuators B 99 288-296 Nakao Y (1995) Noble metal solid sols in poly(methyl) methacrylate. J Colloid Interface Sci 171 386-391 Nayral C, Viala E, Colhere V, Fau P, Senocq F, Maisonnat A, Chaudret B (2000) Synthesis and use of a novel SnO nanomaterial for gas sensing. Appl Surf Sci 164 219-226... 

W. Zhao, T. Cao, and J.M. White, On the origin of green emission in polyfluorene polymers the roles of thermal oxidation degradation and crosslinking, Adv. Fund. Mater., 14 783-790, 2004. 

Cao L, Liu Z, Zhu T (2006) Eormation Mechanisms of Non-Spherical Gold Nanoparticles During Seeding Growth Roles of Anion Adsorption and Reduction Rate. J Colloid Interface Sci 293 67-69... 

Warner CM, McElhinny AS, Wu L, Cieluch C, Ke X, Cao W, Tang C, Exley GE. Role of the Ped gene and apoptosis genes in control of preimplantation development. J Assist Reprod Genet 1998 15(5) 331-337. 

MgO was necessary to form montmorillonite from a variety of starting materials. When Mg was not present, analcite wasformed and all the A1 was presumably tetrahedrally coordinated. When CaO was added to the starting material, rather than MgO, tober-morite was formed and A1 did not enter into any crystalline silicate structure. Although Hawkins and Roy (1963) and Keller (1964) believe the role of Mg is to precipitate the Si, it is possible that its major contribution is, in some manner, assisting the A1 in assuming six-fold coordination under conditions where it would normally take four-fold coordination. 

Kitazawa T, Hashiba K, Cao J, Unno T, Komori S, Yamada M, Wess J, Taneike T (2007) Functional roles of muscarinic M2 and M3 receptors in mouse stomach motility studies with muscarinic receptor knockout mice. Eur J Pharmacol 554 212-22 Knauber J, Muller WE (2000) Decreased exploratory activity and impaired passive avoidance behaviour in mice deficient for the aiB-adrenoceptor. Eur Neuropsychopharmacol 10 423-7 Koshimizu TA, Tanoue A, Tsujimoto G (2006) Clinical implications from studies of oti adrenergic receptor knockout mice. Biochem Pharmacol. 

Ichida F, Nishimura R, Hata K, Matsubara T, Ikeda F, Hisada K, Yatani H, Cao X, Komori T, Yamaguchi A and Yoneda T (2004) Reciprocal roles of Msx2 in regulation of osteoblast and adipocyte differentiation. J. Biol. Chem. 279 34015-34022. 

W. Kolodziejczyk et al., Probing the role of P=0 stretching mode enhancement in nerve-agent sensors Simulation of the adsorption of diisopropylfluorophosphate on the model MgO and CaO surfaces. Chem. Phys. Lett. 450, 138-143 (2007)... 

Ostromyslensky [90] observed that rubber could be vulcanized in the absence of sulphur or its compounds if small quantities of aromatic nitro compounds, e.g. nitrobenzene, dinitro- or sym- trinitro-benzene, tetranitronaphthalene plus certain oxidizing compounds, such as benzoyl peroxide, were added to it. The resultant vulcanized rubber had mechanical properties not inferior to those of a product vulcanized by sulphur alone, and when free from accelerators it exhibited a greater resistance to ageing. Some metal oxides, such as PbO, CaO, BaO, promoted vulcanization by nitro compounds. Urea played the role of an accelerator of vulcanization. These observations have been confirmed in more recent studies by other workers. 

Baillie, L., Hibbs, S., Tsai, P., Cao, G-L., Rosen, G.M. (2005). Role of superoxide in the germaination of Bacillus anthracis endospores. FEMS Microbiol. Lett. 245 33-8. 

Falguera M, Perez-Mur J, Pnig T, Cao G. Stndy of the role of vitamin B12 and fohnic acid snpplementation in preventing hematologic toxicity of zidovndine. Enr J Haematol 1995 55(2) 97-102. 

Benito et al. [15] have investigated, in unusual detail, the texture of the CaO formed in the decomposition of CaCOj, to determine the role of CO2 in promoting diminution of the surface area of the initially highly divided oxide product. At low pressures, CO2 catalyses the decrease in CaO surface area to about 90 m g. Further coarsening proceeds by grain boundaiy and bulk diffusion processes. 

Figure 1 presents the dependence of the catalytic activity and isobutane selectivity of samples precipitated at pH = 9 on the CaO concentration. This study made it possible to evaluate the role of the cubic solid solution in their catalytic properties. One can see an obvious maximum on the dependence of the activity on the alkaline earth metal concentration in the structure of Zrj.xCaxOz-x solid solution. Without calcium the catalytic activity is low. This agrees with the literature data that sulfation of a calcined monoclinic phase without any special treatment does not yield an active catalyst [9]. The maximum activity is observed for the samples with the CaO concentration of 5-10 mol.%. The material with the calcium concentration of 50 mol.% does not show any catalytic activity at all. This sample is mostly composed of perovskite crystalline phase CaZrOs. A comparison of the catalytic activity of the samples with their surface areas clearly indicates that the activity growth is mostly caused by the formation of the cubic phase rather than just by an increased surface area. 

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