Metals, variation

One important class of point-of-use processes utilizes a porous polymer containing reactive metals. Variations in the metal and polymer chemistry are made to optimize the process for different gas appHcations. This is an active area of development and purifiers are available for most of the principal specialty gases. 

Here we try to gain insight into the trends in reactivity of the metals without getting lost in too much detail. We therefore invoke rather crude approximations. The electronic structure of many metals shows numerous similarities with respect to the sp band, with the metals behaving essentially as free-electron metals. Variations in properties are due to the extent of filling of the d band. We completely neglect the lanthanides and actinides where a localized f orbital is filled, as these metals hardly play a role in catalysis. 

The Effect of Single Metal Variation in Mo-V-Nb-W/Al203 System on Propane... 

Composition Variations Li depletion is sensitive to interior opacities, which themselves depend on the stellar composition. Small star-to-star variations might cause an Li abundance scatter, which would grow towards lower masses. However, current limits on metallicity variations in the Pleiades (and other clusters) seem too small for this to be the dominant explanation of any scatter [38]. In addition, the correlation of Li-depletion with rotation is unexplained. 

PMS Li depletion is supposed to be very sensitive to overall metallicity. Groups of ZAMS clusters with similar ages but differing metallicities can be used to test this prediction. The results are surprising. Metallicity variations of 0.1-0.2 dex appear to make no difference to PMS Li depletion [2,17]. An explanation might be that whilst [Fe/H] (what is usually measured as a proxy for metallicity) varies, other elements which are important for interior opacities, especially O, Si, Mg,... 

The range of polypropylene microstructures available by procatalyst ligand (and/or metal) variation in the metallocene-methylaluminoxane system is illustrated in Table 3.1 [22,23,101,105,107,112,113,124,127,132,137], The ligands shown in Table 3.1, representative of the particular symmetry and class of the catalyst, are given as examples only. There are a variety of other metallocenes that have been successfully used to obtain polypropylenes of various stereostructures. 

The CMR Turbo is a metallic variation of the CMR that has perforated walls and tongues. Compared to the normal CMR , this variation appears to slightly improve both the capacity and the efficiency (3). 

Metal variation with fixed ancillary-ligand set... 

Contaminants (asphaltic constituents) deposited on the catalyst as coke or metals Variations... 

Radiation damage Superconductivity of bombarded metals Variations of thin film properties Simulation of radiation damage e.g. in nuclear power plants Radiation Chemistry Ion sputtering Ion reflection Radiation decomposition of gases... 

Insertion of impurities Superconductivity of bombarded metals Variations of thin film properties Wear, friction and lubrication of materials Wear, friction and lubrication of materials Chemical state of implanted atoms Reactivity of ion-bombarded surfaces Reactivity of ion-bombarded surfaces Ionization phenomena Charge exchange studies... 

Mn, Tc, Re Complexes H3C-MO3 as an Example of Metal Variation in Potential Catalysts for Aqueous Systems... 

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