Projeto ético-político e assistência social: um estudo do cotidiano de trabalho dos (as) assistentes sociais do Centro Sul / Vale do Salgado-CE

O presente estudo abordou o Projeto Ético-Político do Serviço Social brasileiro, considerando o seu possível tensionamento no âmbito da política de assistência social, na região Centro Sul/Vale do Salgado no estado do Ceará. Portanto, através do nosso estudo, pretendeu-se analisar as possibilidades e os limites de materialização do Projeto Ético-Político Serviço Social brasileiro na política de assistência social, em tal região. Optamos por essa análise por considerarmos imprescindível apreender as tensões impostas a esse Projeto no cotidiano de trabalho profissional do (a) assistente social. E, para tanto, foi imprescindível analisarmos a atual configuração da assistência social, partindo das diretrizes da Política Nacional de Assistência Social e confrontando-as com o processo de municipalização desta política no campo pesquisado. Avaliamos a relevância do presente estudo em decorrência do atual processo de expansão e centralidade da política de assistência social, no cenário brasileiro, como estratégia de alívio à miséria e à pobreza. Tal movimento se realiza expressando um duplo movimento: a implementação do Sistema Único de Assistência Social e a prevalência dos Programas de Transferência de Renda. Esse contexto tem ampliado, sobremaneira, a requisição aos assistentes sociais, que vêm ocupando, majoritariamente, tais espaços sócio-ocupacionais. Entretanto, essa inserção tem se realizado sob condições e relações de trabalho precarizadas, o que pode implicar em uma possível intensificação do tensionamento do Projeto Ético-Político do Serviço Social brasileiro. A pesquisa foi realizada por meio de entrevistas com os (as) profissionais atuantes nos Centros de Referência da Assistência Social (CRASs) e Centros de Referência Especializado da Assistência Social (CREAs), em sete municípios da região selecionada como campo empírico. Os dados analisados também são resultados das visitas institucionais e observações de campo que realizamos no espaço sócio-ocupacional dos (as) profissionais entrevistados (as). A presente pesquisa está assentada no materialismo histórico e dialético, método de apreensão do real, originalmente elaborado por Marx.

利用水生植物清除水体中放射性物质的研究 (Ⅲ)水生植物对Sr~(90)、Y~(91)、Cs~(137)、Ce~(144)的积累、释放及Ca对Sr~(90)吸收的影响

5种水生植物对所用4种放射性同位素都有一定的清除能力,其清除能力的大小不仅取决于生物的种类,而且还取决于生物本身代谢率的高低。试验结果:去污率高的可达80%,积累系数最高可达1,500;水体中含Ca量的多少对生物吸收积累放射性物质的多少有一定的影响;生物在积累放射性物质之后,转移到无放射性物质的水体中将释放出原积累的一部分放射性物质。

Space growth studies of Ce-doped Bi12SiO20 single crystal

Ce-doped Bi12SiO20 (BSO) single crystal was grown on board of the Chinese Spacecraft-Shenzhou No. 3. A cylindrical crystal, 10 mm in diameter and 40 mm in length, was obtained. The morphology of crystals is significantly different for ground- and space-grown portions. The space- and ground-grown crystals have been characterized by Cc concentration distribution, X-ray rocking curve absorption spectrum and micro-Raman spectrum. The results show that the quality of Ce-doped BSO crystal grown in space is more homogeneous and more perfect than that of ground grown one. (C) 2004 Published by Elsevier B.V.

Comparison of space- and ground-grown Ce: Bi12SiO20 single crystals

Ce doped Bi12SiO20 single crystals were grown either on board of the Chinese Spacecraft-Shenzhou No.3 (SZ-3) or on the ground at the same conditions with the exception of microgravity. The surface morphology of crystals clearly showed significant differences between the space- and ground-grown portions. The space- and ground-grown crystals have been measured by X-ray rocking curve, Cc concentration distribution in growth direction, dislocation density, absorption spectrums. These results show that the compositional homogeneity and structural perfection of Ce doped crystal grown in space are obviously improved.

Mossbauer spectroscopic study of R3Fe29-xCrx and R3Fe29-xCrxH,(y)(R = Y, Ce, Nd, Sm, Gd, Tb, and Dy)

Fe-57 Mossbauer spectra for the series of R3Fe29-xCrx (R = Y,Ce, Nd, Sm, Gd, Tb, and Dy) compounds and their hydrides have been measured at 4.2 K. The weighted average hyperfine field at the Fe sites was separated into a 3d-electron contribution, proportional to the average Fe moment, and a transferred contribution due to rare earth moments. The latter was found to increase with the rare earth effective spin (g(J) - 1) J. Hyperfine fields in the hydrides were only slightly larger than in the corresponding alloys.

Photoluminescence and electroluminescence of (Gd2O3-Ga2O3): Ce thin film

A novel electroluminescence oxide phosphor (Gd2O3-Ga2O3):Ce has been prepared by electron beam evaporation. The emission peaks of photoluminescence lie at 390nm and a shoulder at 440nm. However, the electroluminescence of the (Gd2O3-Ga2O3):Ce thin film have four emission peaks at 358nm, 390nm, 439nm and 510nm, respectively. The optical absorption of (Gd2O3-Ga2O3):Ce thin film and the photoluminescence of composite materials with various ratios of Ga2O3/(Gd2O3+Ga2O3) have also been described to investigate the origin of emission of photoluminescence and electroluminescence.

Fe-57 Mossbauer spectroscopic and magnetic studies of R3Fe29-xVx (R = Y, Ce, Nd, Sm, Gd, Tb, and Dy)

Mossbauer spectra for Fe atoms in the series of R3Fe29-xVx (R = Y, Ce, Nd, Sm, Gd, Tb, and Dy) compounds were collected at 4.2 K. The ratio of 14.5 T/mu(B) between the average hyperfine field B-hf and the average Fe magnetic moment mu(Fe)(MS), obtained from our data, in Y3Fe29-xVx is in agreement with that deduced from the RxTy alloys by Gubbens et al. The average Fe magnetic moments mu(Fe)(MS) in these compounds at 4.2 K, deduced from our Mossbauer spectroscopic studies, are in accord with the results of magnetization measurement. The average hyperfine field of the Fe sites for R3Fe29-xVx at 4.2 K increases with increasing values of the rare earth effective spin (g(J) - 1) J, which indicates that there exists a transferred spin polarization induced by the neighboring rare earth atom.

Mossbauer spectroscopy study of Fe-57 in R3Fe29-xTx (R=Y, Ce, Nd, Sm, Gd, Tb and Dy; T=V and Cr)

Fe-57 Mossbauer spectra for the Fe atoms in the R3Fe29-xTx (R=Y, Ce, Nd, Sm, Gd, Tb, Dy; T=V, Cr) compounds were collected at 4.2 K. The analysis of Mossbauer spectra was based on the results of magnetization and neutron powder diffraction measurements. The average Fe magnetic moments at 4.2 K, deduced from our data, are in accord with magnetization measurements. The average hyperfine field of Tb3Fe29-xCrx (x=1.0, 1.5, 2.0, and 3.0) decreases with increasing Cr concentration, which is also in accordance with the variation of the average Fe magnetic moment in the Tb3Fe29-xCrx compounds.

Crystallographic and magnetic properties of hydride R3Fe29-xTxHy (R=Y, Ce, Nd, Sm, Gd, Tb and Dy; T=V and Cr)

The crystallographic and intrinsic magnetic properties of hydride R3Fe29-xTxHy (R=Y, Ce, Nd, Sm, Gd, Tb, and Dy; T=V and Cr) have been investigated. The lattice constants and the unit cell volume of R3Fe29-xTxHy decrease with increasing R atomic number from Nd to Dy, except for Ce, reflecting the lanthanide contraction. Regular anisotropic expansions, mainly along the a- and b-axis rather than along the c-axis, are observed for all the compounds upon hydrogenation. Hydrogenation leads to an increase in Curie temperature. First-order magnetization processes (FOMP) occur in magnetic fields of around 1.5 T and 4.0 T at 4.2 K for Nd3Fe24.5Cr4.5H5.0 and Tb(3)Fc(27.0)Cr(2.0)H(2.8), and around 1.4 T at room temperature for Gd3Fe28.0Cr1.0H4.2 Abnormal crystallographic and magnetic properties of Ce3Fe29-xTxHy suggest that the Ce ion is non-triply ionized.

Hydrogenation and anisotropic expansions in R3Fe29-xTx (R = Y, Ce, Nd, Sm, Gd, Tb and Dy; T = V and Cr)

A systematic study of the phase formation, structure and magnetic properties of the R3Fe29-xTx compounds (R=Y, Ce, Nd, Sm, Gd, Tb, and Dy; T=V and Cr) has been performed upon hydrogenation. The lattice constants and the unit cell volume of R3Fe29-xTxHy decrease with increasing R atomic number from Nd to Dy, except for Ce, reflecting the lanthanide contraction. Regular anisotropic expansions mainly along the a- and b-axis rather than along the c-axis are observed for all of the compounds upon hydrogenation. Hydrogenation leads to an increase in the Curie temperature and a corresponding increase in the saturation magnetization at room temperature for each compound. First order magnetization processes (FOMP) occur in the external magnetic fields for Nd3Fe24.5Cr4.5H5.0, Tb3Fe27.0Cr2.0H2.8, and Gd3Fe28.0Cr1.0H4.2 compounds.

Structural and magnetic properties of hydrides R3Fe29-xVxHy (R = Y, Ce, Nd, Sm, Gd, Tb, and Dy)

A systematic investigation of crystallographic and intrinsic magnetic properties of the hydrides R3Fe29 - xVxHy (R = Y, Ce, Nd, Sm, Gd, Tb, and Dy) has been performed in this work. The lattice constants a, b, and c and the unit cell volume of R3Fe29 - xVxHy decrease with increasing rare-earth atomic number from Nd to Dy, except for Ce, reflecting the lanthanide contraction. Hydrogenation results in regular anisotropic expansions along the a-, b-, and c-axes in this series of hydrides. Abnormal crystallographic and magnetic properties of Ce3Fe27.5V1.5H6.5, like Ce3Fe27.5V1.5, suggest that the Ce ion is non-triply ionized. Hydrogenation leads to the increase in both Curie temperature for all the compounds and in the saturation magnetization at 4.2 K and RT for R3Fe29 - xVx with R = Y, Ce, Nd, Sm, Gd, and Dy, except for Tb. Hydrogenation also leads to a decrease in the anisotropy field at 4.2 K and RT for R3Fe29 - xVx with R = Y, Ce, Nd, Gd, Tb, and Dy, except for Sm. The Ce3Fe27.5V1.5 and Gd3Fe28.4V0.6 show the larger storage of hydrogen with y = 6.5 and 6.9 in these hydrides. (C) 1998 Elsevier Science B.V. All rights reserved.