5,281 research outputs found
Use of dialkyldithiocarbamato complexes of bismuth(III) for the preparation of nano- and microsized Bi2S3 particles and the X-ray crystal structures of [Bi{S2CN(CH3)(C6H13)}(3)] and [Bi{S2CN(CH3)(C6H13)}(3)(C12H8N2)]
A range of bismuth(III) dithiocarbamato complexes were prepared and characterized. The
X-ray crystal structures of the compounds [Bi{S2CN(CH3)(C6H13)}3] (1) and [Bi{S2CN(CH3)-
(C6H13)}3(C12H8N2)] (2) are reported. The preparation of Bi2S3 particulates using a wet
chemical method and involving the thermalysis of Bi(III) dialkyldithiocarbamato complexes
is described. The influence of several experimental parameters on the optical and
morphological properties of the Bi2S3 powders was investigated. Nanosized Bi2S3 colloids
were obtained having long-term stability and showing a blue shift on the optical band edge;
the presence of particles exhibiting quantum size effects is discussed. Morphological welldefined Bi2S3 particles were obtained in which the fiber-type morphology is prevalent.FCT - POCTI/1999/CTM/ 3545
Densidade de semeadura de trigo - uma questão de economia.
Para uma efetiva recomendação da quantidade econômica de semente, necessária para a obtenção da máxima produção de trigo, em termos deste insumo, é muito importante que no cálculo da quantidade de semente sejam considerados os parâmetros: massa de 1.000 sementes, vigor e/ou poder germinativo da semente, densidade de sementes or metro quadrado (estande de plantas/m2) a ser atingido e o espaçamento entre linhas.bitstream/CNPAF/20698/1/comt_54.pd
Neckties in the Tropics: A Model of International Trade and Cultural Diversity
Some cultural goods, like clothes and films, are consumed socially and are thus characterized by the same consumption network externalities as languages. At the same time, producers of new cultural goods in any one country draw on the stock of ideas generated by previous cultural production in all countries. For such goods, costless trade and communication tend to lead to the dominance of one cultural style, increasing utility in the short run but reducing quality and generating cultural stagnation in the long run. Increasing trade costs while keeping communication costs low may reduce welfare by stimulating production of cultural goods that are “compatible” with the dominant style, thereby capturing consumption network externalities, but that add little to the stock of usable ideas. Our two-country analysis suggests a reform of cultural policy whereby import restrictions in the smaller country are removed, and are replaced by subsidies to the fixed costs of production of new cultural goods in its traditional style
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