Effect of Precursor

Figure 1 shows the decomposition sequence for several hydrous precursors and indicates approximate temperatures at which the activated forms occur (1). As activation temperature is increased, the crystal stmctures become more ordered as can be seen by the x-ray diffraction patterns of Figure 2 (2). The similarity of these patterns combined with subtie effects of precursor crystal size, trace impurities, and details of sample preparation have led to some confusion in the Hterature (3). The crystal stmctures of the activated aluminas have, however, been well-documented by x-ray diffraction (4) and by nmr techniques (5).

The effect of precursor-support interactions on the surface composition of supported bimetallic clusters has been studied. In contrast to Pt-Ru bimetallic clusters, silica-supported Ru-Rh and Ru-Ir bimetallic clusters showed no surface enrichment in either metal. Metal particle nucleation in the case of the Pt-Ru bimetallic clusters is suggested to occtir by a mechanism in which the relatively mobile Pt phase is deposited atop a Ru core during reduction. On the other hand, Ru and Rh, which exhibit rather similar precursor support interactions, have similar surface mobilities and do not, therefore, nucleate preferentially in a cherry model configuration. The existence of true bimetallic clusters having mixed metal surface sites is verified using the formation of methane as a catalytic probe. An ensemble requirement of four adjacent Ru surface sites is suggested. 

The beneficial effect of precursors (e.g., lecithin), cholinesterase inhibitors (e.g., physostigmine, donepezil), or drugs with cholinomimetic effects (e.g., bethanechol) for actue mania was discovered in part from the work of Janowsky et al. ( 29), leading to their cholinergic—noradrenergic balance hypothesis. Interestingly, lithium is also able to raise RBC choline concentrations and CNS cholinergic activity ( 274). 

Funk, C. and Brodelius, P.E. (1 990b) Phenylpropanoid metabolism in suspension cultures of Vanilla planifolia Andr. II. Effects of precursor feeding and metabolic inhibitors. Plant Physiology 94, 95-101. 

Westerink BH, De Vries JB (1991) Effect of precursor loading on the synthesis rate and release of dopamine and serotonin in the striatum A microdialysis study in conscious rats. J Neurochem 56 228-233. 

G. Blanco-Brieva, M. C. Capel-Sanchez, J. M. Campos-Martin, J. L. G. Fierro, Effect of precursor nature on the behavior of titanium-polysiloxane homogeneous catalysts in primary alkene epoxi-dation, /. Mol Catal A 269 (2007) 133. 

Klett, J., Hardy, R., Romine, E., et al. (2000). High-thermal-conductivity, mesophase-pitch-derived carbon foams effect of precursor on structure and properties. Carbon, 38, 953—73. 

Gundersen V, Ottersen OP, Storm-Mathisen J (1991) Aspartate- and glutamate-like immunoreactivities in rat hippocampal slices depolarization-induced redistribution and effects of precursors. Eur J Neurosci 3 1281-1299. 

Stachen, M. et al., Effect of precursor impurities on the magnetic properties of uniform Y I c.Oi ellipsoidal particles, Phys. Chem. Chem. Phys., 1,4465, 1999. 

Fig. 1. Effect of precursor on activity of Ir/alumina sulfide catalysts in parallel HDN of pyridine and HDS of thiophene.

Figure 7-Effect of precursors on catalytic behavior of catalysts prepared by sol-gel(T=573 K).

Effect of Precursor and Fuel Composition on BET Surface Area of ZrOj Powder... 

The effect of precursor and fuel composition on BET surface area of ZrOj powder ... 

Matsuura, T. and Kakuda, T. 1990. Effects of precursor, temperature, and illumination on theanine accumulation in tea callus. Agric. Biol. Chem. 54 2283-86. 

The intersection of the reactant and product surfaces (point S) represents the transition state (or activated complex ), and is characterized by a loss of one degree of freedom relative to the reactants or products. The actual electron-transfer event occurs when the reactants reach the transition-state geometry. For bimolecular reactions, the reactants must diffuse through the solvent, collide, and form a precursor complex prior to electron transfer. Hence, disentangling the effects of precursor complex formation from the observed reaction rate can pose a serious challenge to the experimentalist unless this is done, the factors that determine the kinetic activation barrier for the electron-transfer step cannot be identified with certainty. 

Thus far, only one precursor of each of the precious metals has been discussed in the context of the calcination process. In practice, a number of precursors are available and these can play a major role in determining metal location and dispersion (ref. 47). The effect of precursor on rhodium dispersion on alumina is shown in Table 6 where the absorption of NO is used as a measure, of dispersion. 

In Sect. 3.2.2, the effects of precursor states on adsorption kinetics have been discussed. Since even the earliest adsorption experiments show evidence for the influence of weakly bound intermediate states, following the principle of microscopic reversibility it might be expected that desorption kinetics would show the influence of such species. However, desorption experiments are usually carried out at considerably higher temperatures and average lifetimes in such states will be much lower. 

M. Eslamian, N. Ashgriz Effect of precursor, ambient pressure, and temperature on the morphology, crystallinity, and decomposition of powders prepared by spray pyrolysis and drying, Powder Technol. 167 (3), 149-159 (2006a). 

Hu and co-workers have demonstrated the in situ growth of CuInS2 nanocrystals onto nanoporous Ti02 film by solvothermal treatment. They have thoroughly investigated the effect of precursor concentration on the morphology of as grown nanostructures. A typical solvothermal reaction involved the addition of thioacetamide (0.02 M) into a 12 mL... 

Ogawa H, Effects of precursor process oil and heating rate during carbonization on defects and tensile properties of resultant PAN-based carbon-fibers, Nippon Kagaku Kaishi, 10, 927 932, 1994. 

In the Soviet Union orotic acid has been studied for a long time in relation to arteriosclerosis, myocardial infarction [449-450] and various cardiopathogenic changes [451-455]. The effect of precursors of nucleic acid synthesis on myocardial contractile function was followed by Zharov and others [456,457]. However, the effect of orotic acid on the development of myocardial hypertrophy was also studied in other countries [458-463]. 

Genesky, G. Duncan, T. M. Cohen, C., Effect of Precursor Molar Mass on the... 

B. Sailer, F. Schwaigerrer, K. Gibson, H.-J. Meyer, M. Lehmann, L. Woodall, M. Gerards Effect of precursor powder properties on magnetic and electrical transport properties of (Bi,Pb)-2223-tapes, IEEE Trans. Appl. Supercond. 11, 2975 (2001)... 

In the present work cation-substituted barium hexaaluminates have been prepared using mechanical activation methods. The effect of precursors, milling regimes and calcination temperature on their synthesis has been investigated. 

The effect of precursor size not only applies to the same metal but also to different metals. This has been clearly shown by the reactions of metal beta-diketonates on alumina [41] the smallest density was obtained with the largest precursor, namely Ce(thd)4 (see Table 2). 

Figure 15. Effect of precursor size on the surface density of Ni bound on alumina [40].

Dose WM, Donne SW (2011) Heat treated electrolytic manganese dioxide for Li/Mn02 batteries effect of precursor properties. J Electrochem Soc 158 A1036-A1041... 

Whitmer S, van der Heijden R, Verpoorte R (2002) Effect of precursor feeding on alkaloid accumulation by a tryptophan decarboxylase over-expressing transgenic cell line T22 of Catharanthus roseus. J Biotechnol 96 193-203. doi 10.1016/S0168-1656(02)00027-5... 

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