Neodymium surface

Supported Ziegler-type neodymium surface species (54, see below) have been prepared by mixing molecular components composed of [Nd(naph)3] (derived from naphthenonic acids) and alkyl aluminium reagents such as Al2Et3Cl3, Al( Bu)3 and/or Al( Bu)2H at 50-60°C with silica (source QiLu Petrochemicals Co., China) [158-160]. Although the immobihzed neodymium species are iU-defined, the materials display interesting properties in butadiene polymerization (Section 12.4.1.2). 

Y > Sm > Nd) [108]. Neodymium surface species 9 generated by silylamido alkoxo secondary ligand exchange was more efficient in e-CL polymerization, producing well-defined poly(CL)s with controllable molecular weight and polydis-persity [114]. 

A similar study with materials [Ln N(SiMe3)2 3] AS-380. (T = 250, 500, 700°C) revealed the implications of thermal pretreatment of the support for ethylene polymerization [117]. Materials featuring predominantly monopodal neodymium silylamido surface species produced the most achve catalysts [12b (100% monopodal) > 13b (40%)> 14b (25%), Table 12.6 cf, Nd[N(SiMe3)2]3 0.03 kg-PE molm h bar ]. Apparently, extensive replacement of silylamido by (surface) siloxo ligands, that is, an increase of podality of the supported species at... 

Nagano,T Isobe, H. Nakhshima, S. Ashisa-ki,M. (2002) Characterization of iron hydroxides in a weathered rock surface by visible microspectroscopy. Appl. Spectr. 56 651—657 Nagano,T Mitamura, H. Nakayama, S. Na-kashima, S. (1999) Formation of goefhite and hematite from neodymium-containing ferri-hydrite suspensions. Clays Clay Min. 47 748-754... 

Incorporate the neodymium magnet into the body of the paste of graphite-epoxy composite, 2 mm under the surface of the electrode [1] and continue placing the paste until filling all the cavity. Cure the conducting composite at 40°C during 1 week. Once the resin is hardened, polish the surface first with abrasive paper and then with alumina paper. 

Tris-allyl-neodymium Nd(//3-C3I Ishdioxane which performs as a single site catalyst in solution polymerization was heterogenized on various silica supports which differed in specific surface area and pore volume. The catalyst was activated by MAO. In the solution polymerization the best of the supported catalysts was 100 times more active (determined by the rate constant) than the respective unsupported catalyst [408]. 

In addition to the studies in which supported catalysts are exclusively used for gas-phase polymerizations one study is available in which the supported catalyst is optimized in a solution process prior to its application in the gas phase. Tris-allyl-neodymium [Nd(/ 3- C3H5)-dioxane] which is a known catalyst in solution BD polymerization is heterogenized on various silica supports differing in specific surface area and pore volume. The catalyst is activated by MAO. In solution polymerization the best of the supported catalysts is 100 times more active (determined by the rate constant) than the respective unsupported catalyst [408]. In addition to the polymerization in solution, the supported allyl Nd catalyst is applied for the gas-phase polymerization of BD [578,579] the performance of which is characterized by macroscopic consumption of gaseous BD and in-situ-analysis of BD insertion [580]. 

When the calcium plaque is thick, it can be removed by scraping with a scalpel or by performing a superficial keratectomy. Other reported methods include the use of a diamond burr, neodymium-yttrium aluminum garnet (Nd YAG) laser, lamellar keratoplasty, and PTK. A recent treatment option described the combined use of superficial lamellar keratectomy, NaEDTA chelation, and amni-otic membrane transplantation. In this procedure the calcific lesions were treated with NaEDTA and a blunt superficial lamellar keratectomy was performed. Once a smooth ocular surface was achieved, an amniotic membrane was transplanted to replace the excised epithelium and stroma. The procedure resulted in the... 

Surface waters show more variable neodymium-isotope ratios than intermediate and deep waters (Figure 5). In contrast to the dominance... 

Silicate is depleted from surface waters by biological processes and remineralized in the deep water. Moreover, silicate tends to accumulate in water masses as they age (cf. Broecker and Peng, 1982). These processes account for both the increasing concentration of silicate with depth, and its increasing concentrations from the North Atlantic to the circum-Antarctic to the Pacific. With a few exceptions (notably the North Atlantic), neodymium abundances show a smooth increase with depth, and in deep water they are highest in the Pacific, lowest in the Atlantic, and intermediate in the Indian (Figure 6). 

---