Subject yttrium

Radioisotopes are also used in radiation therapy to treat cancer. The goal in radiation therapy is to kill malignant cells, while protecting healthy tissue from radiation effects. Radioisotopes such as yttrium-90, a beta emitter, may be placed directly in the tumor. Alternatively, the diseased tissue may be subjected to beams of gamma radiation. Cobalt-60 used in radiation therapy is prepared by a series of transmutations ... 

In general, both cordierite and metallic monoliths are unsuitable as catalytic supports. To process a monolith into an active monolithic catalyst, a layer of porous catalytic support must be deposited on the walls between channels. y-Alumina appeared to be the most effective support for automotive catalysts. The alumina layer is deposited by sol-gel technique (so called washcoating). Adherence of 7-alumina to cordierite is relatively strong. However, to form the stable 7-alumina layer on a metallic surface, we need to use an appropriate alloy that is appropriately processed before the layer is deposited. Stainless steel containing chromium, aluminum, and yttrium subjected to thermal treatment under oxidizing conditions meets requirements of automotive converters. Aluminum in the steel is oxidized to form 7-alumina needles (whiskers) protruding above the metal... 

Sample Solutions. The urine sample solutions all originated from one composite urine sample. The latter was made by combining 150-mL aliquots of the entire first-morning voids of 16, presumably healthy, male subjects. Aliquots of the composite were used to prepare three sets of sample solutions as indicated in Table IV. The solutions in each set were "spiked with internal reference elements and with appropriate volumes of multielement stock solution to make a (multiple) standard addition series (12). The final gallium and yttrium internal reference-element concentrations were 1.0 and 0.1 mg/L, respectively, for both the reference and standard addition solutions. The added analyte concentrations for both the reference and standard addition solutions were 0, 2, 4, 10, and 20 times the approximate "normal analyte concentrations for urine, as listed in Table II. 

In 1996, a report appeared in Nature of experiments in which a 500 nm thick film of 5dtrium (coated with a 5-20 nm layer of palladium to prevent aerial oxidation) was subjected to 10 Pa pressure of H2 gas at room temperature. As H2 diffused through the Pd layer, the latter catalysed the dissociation of H2 into H atoms which then entered the yttrium lattice. A series of observations followed ... 

Yttrium has been found in samples of lunar crystalline rocks (namely in relatively yttrium-rich mineral and grain-si/e fractions, light and dark clasts) collected during the Apollo 11-15 and Luna 16 missions. A relatively high amount of yttrium was found in these samples (Gmelin et al. 1980). Indeed, the proportion of yttrium to rare earth elements (REE including ratios and correlations of Y and REE to other elements) was used as a criterion for the classification of lunar rocks. Yttrium and Rare Earths were also a subject of study in the space, for example, in stellar spectra in the solar atmosphere, and in different types of meteorites and mesosiderites. 

The increased production and use of yttrium in technical materials (see Section 28.3.1) might cause contamination of the human environment, and this should be the subject of interdisciplinary studies focused on primary prevention. Most importantly, the inhalation of yttrium compounds may be toxic and also possibly carcinogenic for humans. 

Aluminum nitride powder synthesized by high-temperature routes can be sintered to a density of more than 97% of the theoretical density by adding calcium or yttrium compounds as sintering aids [52-54]. Therefore, new processing routes to aluminum nitride predominantly aim at powders with lower quantities of cationic impurities. In addition, the formation of aluminum nitride coatings [55-58] or fibers [59] has become subject of extensive research. 

Refining of the particle size can be achieved by etching of bulk sample. For example, the nanosize zirconia powder doped with yttrium has been prepared by etching of yttrium containing polycrystalline BaZrOs or NaaZrOs [15]. Preliminary sintered ceramics of BaZrOs or Na2Zr03 doped with yttrium was subjected to hydrothermal treatment to eliminate the undesirable ions of Ba + or Na+ in nitric acid solution or supercritical water. The etching precipitate represents yttrium-stabilized zirconia nanopowder with particle size of 3-15 nm. 

Superconductors are materials that have the ability to conduct electricity without resistance below a critical temperature above absolute zero. The phenomenon of superconductivity was first seen in mercury at liquid helium temperatures. Great interest developed in this area in the late 1980s, when Muller and Bednorz discovered that even ceramic-like materials can exhibit superconductivity. C. W. Chu subsequently found yttrium barium copper oxide (YBCO) to be superconducting above liquid nitrogen temperatures. Indeed, various books are devoted to this subject. > In the following subsections we highlight representative force field applications that have aided the understanding of static and dynamic properties of superconductors. 

In this article, we will begin with an overview of the structures of binary rare-earth halides, RXz (with R being a cation of a rare-earth element, scandium, yttrium, lanthanum and cerium through lutetium and X a halide ion). Because binary halides were the subject of several excellent reviews, also in this handbook (Haschke 1979, Eick 1994), they will be mentioned only briefly. 

The lanthanide elements comprise lanthanum and the 14 elements (cerium to lutetium) that follow lanthanum in the periodic table. Frequently, the terms lanthanides and lanthanons are used as synonyms for the rare earth elements (REEs), although strictly the REEs comprise the lanthanides and also yttrium, which together with gadolinium, the subject of Chap. 29, is omitted from this chapter. As in many accounts of the chemistry of the lanthanides, will be used as the collective chemical symbol for the trivalent cations. 

In order to produce Y203-stabilized zirconia with homogeneous distribution, sol-gel processes or coprecipitation have been adopted, based on the hydrolysis of stoichiometric mixtures of zirconyl chloride and yttrium trichloride (see, e.g.. Carter et al, 2009). The hydroxides formed are subsequently subjected to aceo-tropic distillation, drying, calcining between 850 and 950 °C, wet milling, and spray-drying. 

L.M. Vallarino, Macrocycle complexes of the lanthanlde(fll), yttrium(III), and dloxouranium (VI) Ions from metal-templated syntheses 443 Errata 513 Subject index 515... 

John W. Arblaster, Selected values of the thermodynamic properties of scandium, yttrium, and the lanthanide elements 321 Author index 567 Subject index 591... 

Another subject class is concerned with diluted 4f metals. Sarkissian and Coles (1976) have tried to distinguish between spin-glass freezing and helical ordering in solid solutions of Gd, Tb and Dy in Y and Sc by means of resistivity and susceptibility measurements (fig. 12). These materials have attracted recent interest again, because some are candidates for anisotropic spin glasses (Baberschke et al. 1984). It also turned out that spin-glass behavior in yttrium based alloys occurs at much lower concentrations than previously claimed. 

This review will be limited to certain thermodynamic properties of gaseous species of the elements yttrium, scandium, and lanthanum to lutetium. The dissociation enthalpies and enthalpies of formation are the two quantities which are evaluated and tabulated for all the species considered here. There have been two recent reviews by Gingerich (1980a, 1985) on this subject and should be referred to for literature references. In this review, the values reported in the literature have been recalculated in a large number of cases using newer data for reference systems. 

---