990 resultados para SM


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This research led to the discovery of one of the best preserved remnants of the Earth's surficial environment 3.47 billion years ago. These ancient volcanic and sedimentary rocks contain original minerals and textures that are rare in rocks of this age. The research concentrated on chemical analysis of volcanic rocks to differentiate secondary alteration from the primary magmatic signature. This study contributes to our understanding of melting processes and geochemical reservoirs in the early Earth, which is vital for forward modelling of Earth's geodynamic evolution.

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Under senare tid har förekomsten av samarbete mellan konkurrerande sm-företag ökat. Forskningen kring ämnet har dock bedrivits i mindre skala, framför allt om man beaktar finländska (nordiska) förhållanden. Syftet med denna undersökning är att kartlägga förekomsten av samarbete mellan konkurrerande sm-företag i Österbotten (Finland), samt beskriva dessa. Gällande demografiska variabler jämförs dessa företag även med sm-företag som inte samarbetar. Data insamlades genom en enkät utskickad i november 2001 till 345 sm-företag i Österbotten. Svarsprocenten var 35.1. Av de respondenter som besvarade enkäten, var 47.9 procent involverade i ett eller flera samarbeten med ett eller flera företag som var deras konkurrenter. Samarbete mellan konkurrenter är således inte ett ovanligt fenomen, utan innefattar allt från informella, operativa samarbeten till formella, strategiskt viktiga samarbeten. Samarbete inom produktion var den mest vanligt förekommande formen av samarbete. Partnern kom från Finland, även om målmarknaderna för samarbetet fanns både i Finland och i utlandet. Denna undersökning kunde inte identifiera någon större skillnad mellan de sm-företag som samarbetade med konkurrenter och de sm-företag som inte samarbetade. Det intressanta är således att det inte verkar finnas några skillnader vad gäller ålder, omsättning, omsättningsökning, underleverans- och exportverksamhet mellan de samarbetande och de icke samarbetande företagen. Skillnaderna bör således sökas i andra variabler. Den enda signifikanta skillnaden kunde upptäckas i upplevelsen av konkurrens. Tidigare forskning har identifierat att osäkerhet i konkurrensen är ett incitament till att börja samarbeta med konkurrenter. Denna undersökning förstärker detta antagande. De samarbetande företagen upplevde att konkurrensen var hårdare än de icke samarbetande företagen. Bland de samarbetande företagen var det speciellt de mindre (med en personalstyrka mellan 10 och 50 arbetstagare) som upplevde att konkurrensen var hård. Undersökningen har finansierats med stipendiemedel från Sparbanksstiftelsen i Vasa och Handlande Gustav Svanljungs fond.

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Rapid multiplication of axillary meristems and direct shoot development occurred from nodal explants of mature Eucalyptus tereticornis Sm. with 5.3 mgrM NAA, 1.1 mgrM IAA and 4.4 mgrM BA in Murashige-Skoog medium. Repeated subcultures of the second generation shoot cultures into low cytokinin-auxin containing media (0.44�0.88 mgrM BA+0.1 mgrM NAA) yielded axillary microshoots in large numbers. Half-strength MS liquid medium with 4.9 mgrM IBA, 5.5 mgrM IAA and 5.3 mgrM NAA for four days, half-strength semi-solid hormonefree MS medium with charcoal, and MS liquid medium without charcoal and hormones, in sequence, induced rooting of shoots in the dark. This system is suitable for the mass propagation of this difficult-to-root eucalypt.

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Scheelite type solid electrolytes, Li(0.5)Ce(0.5-x)Ln(x)MoO(4) (x = 0 and 0.25, Ln = Pr, Sm) have been synthesized using a solid state method. Their structure and ionic conductivity (a) were obtained by single crystal X-ray diffraction and ac-impedance spectroscopy, respectively. X-ray diffraction studies reveal a space group of I4(1)/a for Li(0.5)Ce(0.5-x)Ln(x)MoO(4) (x = 0 and 0.25, Ln = Pr, Sm) scheelite compounds. The unsubstituted Li0.5Ce0.5MoO4 showed lithium ion conductivity similar to 10(-5)-10(-3) Omega(-1)cm(-1) in the temperature range of 300-700 degrees C (sigma = 2.5 x 10(-3) Omega(-1) cm(-1) at 700 degrees C). The substituted compounds show lower conductivity compared to the unsubstituted compound, with the magnitude of ionic conductivity being two (in the high temperature regime) to one order (in the low temperature regime) lower than the unsubstituted compound. Since these scheelite type structures show significant conductivity, the series of compounds could serve in high temperature lithium battery operations.

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A wet chemical route is developed for the preparation of Sr2CeO4 denoted the carbonate-gel composite technique. This involves the coprecipitation of strontium as fine particles of carbonates within hydrated gels of ceria (CeO2.xH(2)O, 40Sm3+ or Yb3+ which in turn, have unique charge-transfer associated energy levels in the excited states in oxides. Efficient energy transfer occurs from Ce4+-O2- CT state to trivalent lanthanide ions (Ln(3+)) if the latter has CT excited states, leading to sensitizer-activator relation, through non-resonance process involving exchange interaction. Yb3+-substituted Sr2CeO4 does not show any line emission because the energy of Yb3+-O2- CT level is higher than that of the Ce4+-O2- CT level. Sr2-xEuxCeO4+x/2 shows white emission at xless than or equal to0.02 because of the dominant intensities of D-5(2)-F-7(0-3) transitions in blue-green region whereas the intensities of D-5(0)-F-7(0-3) transitions in orange-red regions dominate at concentrations xgreater than or equal to0.03 and give red emission. The appearance of all the emissions from D-5(2), D-5(1) and D-5(0) excited states to the F-7(0-3) ground multiplets of Eu3+ is explained on the basis of the shift from the hypersensitive electric-dipole to magnetic-dipole related transitions with the variation in site symmetry with increasing concentration of Eu3+. White emission of Sr2-x SmxCeO4+x/2 at xless than or equal to0.02 is due the co-existence of Ce4+-O2- CT emission and (4)G(4)(5/2)-H-6(J) Sm3+ transitions whereas only the Sm3+ red emission prevails for xgreater than or equal to0.03. The above unique changes in PL emission features are explained in terms of the changes in NNN environments of Ce4+. Quenching of Ce4+-O2- CT emission by other Ln(3+) is due to the ground state crossover arising out of the NNN interactions.

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The synthesis and DNA photocleavage studies of furano3,2-c]-1,2,3,4-tetrahydroquinolines have been reported. Sm(III)nitrate was found to be an efficient for the Diels-Alder reaction of aryl amines with 2,3-dihydrofuran to offer the corresponding furano3,2-c]-1,2,3,4-tetrahydroquinolines derivatives as a mixture of cis/trans stereoisomers in moderate yields. The aqueous solubility of acid catalyst can be recycled without significant loss of activity. The DNA photocleavage studies shows that, the cis/trans stereoisomers are good DNA cleavage mimic in terms of molecular structure. (C) 2012 Elsevier B.V. All rights reserved.