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11.
文章介绍了新材料的重要性及发展方向,分析化学在新材料研制中起着耳目的作用,另一方面新材料也为分析化学的进展提供了课题与条件。微量分析、微区分析、表面分析是此领域中的重点。在未来的发展中,分析化学在材料的发展中的地位不会改变,并期待着分析灵敏度与空间分辩率的进一步提高。 相似文献
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The crystal structure of a second high-pressure copper vanadate phase, CuVO3(II), has been determined and refined by full-matrix least-squares procedures using automatic diffractometer data to a residual R = 0.042 (Rw = 0.051). The space group is rhombohedral, , with hexagonal unit cell a = 4.966(2) and c = 14.084(5) Å [aR = 5.501(2) Å and α = 53.66(3)°]. The structure is the fully ordered ilmenite-type and, on the basis of published magnetic data and the interatomic distances, the valence distribution Cu+V5+O3 is proposed. This represents a unique example of Cu+ in an octahedral environment. 相似文献
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用原子吸收法或极谱法测定了对例慢性肾炎病人(A组)和24例慢性肾衰病人(B组)及40名健康人(对照组,C组)全血中的Fe、Zn、Cu、Mn、Se、Pb和Ga含量。结果表明,A组与C组比较.血中Fe的含量A组明显低于C组(P<0.05),Zn、Mn和Se的含量A组均非常明显低于C组(P<0.01),Pb含量A组非常明显高于C组(P<0.01),Cu和Ca含量两组间均无明显差异(P>0.05);B组与C组比较,Fe含量B组明显低于C组(P<0.06),Se含量则B组明显高于C组(P<0.05);Zn、Mn、Cu、Ga含量B组均非常明显低于C组(P<0.01),而Pb含量则B组非常明显高于C组(P<0.01)。 相似文献
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J. Tolchard 《Journal of solid state chemistry》2007,180(10):2808-2815
The chemical and physical compatibility of SrCeO3 is investigated with respect to LaMO3 (M=Mn, Fe, Co) and La2−xSrxNiO4 (x=0, 0.8), via the reaction of fine-grained powder compacts and solid-state diffusion couples. Compositions were chosen so as to give predictive insight into possible candidate materials for all-oxide electrochemical devices. Results show the primary reaction in these systems to be the dissolution of SrO from SrCeO3 into the LaMO3/La2−xSrxNiO4, and corresponding formation of La-doped CeO2. Reaction kinetics are observed to be relatively fast, with element profiles suggesting the diffusion of Sr2+ in ceria to be surprisingly rapid. It is demonstrated that perovskite starting materials represent poor candidates for use with SrCeO3, reacting completely to form Ruddlesden-Popper/K2NiF4 type oxides. Reaction with La2NiO4 is less pronounced, and formation of secondary phases suppressed for the composition La1.2Sr0.8NiO4. It is thus concluded that Ruddlesden-Popper type oxides represent good candidate materials for use with a SrCeO3-based electrolytes when doped with appropriate levels of Sr. 相似文献
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Modern condensed-matter physics is increasingly concerned with the design, synthesis, analysis, and exploitation of chemically complex materials and structures. Complex metal oxides and strongly correlated electron systems such as YBa2Cu3O7−x and La1−xSrxMnO3 are paradigmatic examples. Their production in the form of high-quality thin films is of both technological and fundamental importance and has stimulated a concerted effort in the last two decades to find and optimize efficient techniques to this end. This review discusses the physics behind and the requirements for synthesizing high-quality films of such materials and examines fundamental aspects of the growth processes associated with magnetron sputtering and pulsed laser deposition, the two techniques which presently offer the best solutions in this burgeoning field. 相似文献
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Kyle Siegrist 《Journal of Theoretical Probability》1994,7(4):725-737
Three fundamental characterizations of the standard exponential distribution on [0, ) are the remaining life, memoryless and constant failure properties. Analogs of these properties are studied for distributions on a class of semigroups in which the semigroup operation replaces addition, a compatible partial order replaces the ordinary order, and a left-invariant measure replaces Lebesgue measure. Partial characterizations of exponential distributions on such semigroups are obtained and the semigroup formulation provides new characterizations of certain aging properties studied in reliability-increasing failure rate, new better than used, and increasing failure rate average. 相似文献
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Zn3V3O8 two-dimensional micro sheets are successfully synthesized by combination of solvothermal method and heat treatment. The Zn3V3O8 has better electrochemical performances after calcinations. 相似文献
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