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1.
Artigo em Inglês | MEDLINE | ID: mdl-24995416

RESUMO

A new organic-inorganic hybrid material, 1,4-bis(3-ammoniumpropyl) piperazinium pentachloridocuprate(II) chloride tetrahydrate [(C10H28N4)CuCl5Cl⋅4H2O], has been synthesized and characterized by X-ray diffraction, UV-visible absorption, Infrared and Raman spectroscopy. The compound crystallizes in the orthorhombic system and Pnma space group with a=8.18 (3)Å, b=10.96 (5)Å, c=21.26 (9)Å, V=2254.3 (15)Å(3). In this structure, the Cu(2+) ion, surrounded by five chlorides, adopts the square pyramidal coordination geometry. The structure of this compound consists of tetraprotonated 1,4-bis(3-ammoniumpropyl) piperazinium cations and the anionic sublattice is built up of isolated, square pyramid [CuCl5](3)(-) units, chloride ion Cl(-) and water molecules connected with each other by hydrogen bonds. Organic and inorganic entities are interconnected by means of hydrogen bonding contacts [NH⋯O(Cl), O(W)H⋯Cl and O(W)H⋯O]. Furthermore, the room temperature IR and Raman spectra of the title compound were recorded and analyzed on the basis of literature data. The optical study was also investigated by UV-Vis absorption. In fact, the organic-inorganic hybrid crystal thin film can be easily prepared by spin-coating method from the ethanol solution of the (C10H28N4)CuCl5Cl⋅4H2O hybrid compound and it showed absorptions characteristics of CuCl based layered compounds centered at 275 and 374 nm.


Assuntos
Complexos de Coordenação/química , Cobre/química , Modelos Moleculares , Técnicas de Química Sintética , Cristalografia por Raios X , Ligação de Hidrogênio , Espectrofotometria Ultravioleta , Análise Espectral Raman , Temperatura
2.
J Nanosci Nanotechnol ; 8(4): 2029-36, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18572610

RESUMO

Nanostructured Fe-8P (wt%) powder mixture was prepared by high energy ball milling in a planetary ball mill (Fritsch P7) under argon atmosphere. The morphology of the particles, the phase identification and the alloying evolution process as a function of milling time are studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) and 57Fe Mössbauer spectrometry (MS), respectively. Refinement based on Rietveld method of the XRD patterns and the Mössbauer spectra analysis show that the Fe(x)P (1 < x < 2) and Fe2P phosphide phases are the main product after 3 h of milling (approximately 10%). From the XRD Rietveld refinement, it is observed that the Fe2P phase disappears completely after 12 h of milling, while the Fe3P nanophase appears after 9 h and remains for larger milling duration. The lattice structure distortion is evidenced by the lattice parameter changes of the milled products. A two structure state of the alpha-Fe(P) solid solution: alpha-Fe1 and alpha-Fe2 is confirmed by both the XRD and MS measurements. After milling for 21 h, a mixture of a disordered two phase alpha-Fe(P) solid solution, Fe3P nanophase and a small amount of a paramagnetic FeP phosphide phase (approximately 2%) is obtained.


Assuntos
Cristalização/métodos , Ferro/química , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Nanotecnologia/métodos , Misturas Complexas/química , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Tamanho da Partícula , Pós , Propriedades de Superfície
3.
J Food Sci ; 72(2): E57-63, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17995834

RESUMO

In this study, the parameters heating rate, dielectric factors, and specific heat capacity, which determine the heating profiles and the dissipation of energy during microwave heating, were obtained for precooked pork patties. The pork patties studied were lean meat, pure back fat, and several lean meat/back fat mixtures. Microwave heating at 798 W power was not sufficient to accelerate the heating rates in 100% lean meat compared to 415 W. However, samples were able to heat up faster and dissipate more energy at 798 W power as fat content increased and moisture content decreased. The recorded differences in the specific heat capacity of the studied materials as a function of temperature seemed not to be the key factor to explain the observed temperature rises. Temperature rise seemed to have more to do with the interactions of fat with the electromagnetic field, and with viscosity changes during phase transitions. Trends found for the dielectric properties over microwave heating of meat products agree with data from other authors, but the influence of parameters related to the sample composition and structure should be taken into account. The dissipation factors (epsilon''/epsilon') provided a good approximation to the capacity of the samples containing lean meat and the lean meat/fat mixtures to transform the electromagnetic energy into heat. Neither the dielectric constant nor the loss or dissipation factors were able to clarify the high amount of energy transformed into heat in 100% back fat. Penetration depth and reflected power indicated that back fat allowed microwave energy to be repeatedly redirected to the material.


Assuntos
Gorduras na Dieta/análise , Manipulação de Alimentos/métodos , Temperatura Alta , Produtos da Carne/análise , Micro-Ondas , Animais , Qualidade de Produtos para o Consumidor , Culinária/métodos , Humanos , Radiação , Suínos
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