Luminescence studies and EPR investigation of derived Eu doped ZnO

ZnO:Eu (0.1 mol%) nanopowders have been synthesized by auto ignition based low temperature solution combustion method. Powder X-ray diffraction (PXRD) patterns confirm the nanosized particles which exhibit hexagonal wurtzite structure. The crystallite size estimated from Scherrer's formula was found to be in the range 35-39 nm. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies reveal particles are agglomerated with quasi-hexagonal morphology. A blue shift of absorption edge with increase in band gap is observed for Eu doped ZnO samples. Upon 254 nm excitation, ZnO:Eu nanopowders show peaks in regions blue (420-484 nm), green (528 nm) and red (600 nm) which corresponds to both Eu2+ and Eu3+ ions. The electron paramagnetic resonance (EPR) spectrum exhibits a broad resonance signal at g= 4.195 which is attributed to Eu2+ ions. Further, EPR and thermo-luminescence (TL) studies reveal presence of native defects in this phosphor. Using TL glow peaks the trap parameters have been evaluated and discussed. (C) 2014 Elsevier B.V. All rights reserved.

La recepción del Concilio Vaticano II en el pueblo de Dios : testimonios sobre la renovación desde las formas de vida

Presentación: 1. Recepción del Concilio Vaticano II. Hablar de “recepción” de un concilio supone un conjunto de hechos –dentro de la Iglesia– que hace posible que la determinación o decisión de un concilio –sus contenidos de verdad– sea recibida por parte de las iglesias como conveniente para su vida; preguntarse por la recepción de un concilio es plantear cómo se desarrolla el proceso por el cual se da un consentimiento o “confirmación” por parte de las iglesias...

O livro didático de alfabetização na era do letramento: uma análise crítica

Essa pesquisa insere-se em um contexto de muitas discussões acerca da qualidade da educação no Brasil, motivadas principalmente pelos maus resultados atingidos pelo país em exames internacionais. Os constantes debates têm dado margem, inclusive, a movimentos que, culpando os PCNs pelo fracasso generalizado na alfabetização, clamam pela volta de um ensino tradicional. De fato, apesar das imensas contribuições trazidas pelos estudos que embasam os PCNs, apenas a sua institucionalização não garantiu a ocorrência de mudanças efetivas na educação. Principalmente no campo da alfabetização, interpretações equivocadas levaram, por exemplo, ao desencadeamento de um processo de desmetodização do ensino, caracterizado pela exclusão total, nos últimos anos, das questões de ordem metodológica das pautas de discussões. Tal fenômeno, denominado por Soares (2004) de desinvenção da alfabetização, e também abordado por outros pesquisadores (cf. MORAIS, 2006; FRADE, 2003; CARVALHO, 2007), obviamente, acabou se refletindo nos novos livros didáticos, avaliados e recomendados pelo MEC. O problema é que os novos livros parecem não estar satisfazendo às necessidades dos docentes. Estudos recentes têm revelado tanto uma insatisfação desses profissionais em relação a tais materiais quanto a manutenção de práticas didáticas preconizadas pelos métodos tradicionais (Cf. BRITO et al., 2007; SILVA 2008; e MORAIS E ALBURQUERQUE, 2008). Considerando-se que: (a) hoje já se reconhece que os processos de alfabetização e letramento são complementares e indissociáveis (SOARES, 2004); (b) na realidade brasileira os livros didáticos ainda são recursos centrais no trabalho em sala de aula; (c) as obras são avaliadas a partir de rígidos critérios, alinhados às mais recentes teorias; e (d), a disponibilização gratuita desses materiais demanda um alto investimento do governo, o objetivo deste estudo foi analisar criticamente um dos livros didáticos de alfabetização do PNLD/2010 (L.E.R., Leitura, escrita e reflexão 1 ano, FTD), na tentativa de levantar pistas sobre os possíveis motivos dessa não-adesão dos docentes aos novos livros. Para tanto, foi realizada uma análise documental crítica, de abordagem qualitativa, que observou na obra os seguintes aspectos: o espaço dedicado ao ensino do sistema de escrita alfabética; a existência de articulação desse trabalho com o de letramento; a coerência entre a orientação pedagógica declarada e as atividades propostas; e a clareza e objetividade das instruções e sugestões fornecidas ao docente. As análises realizadas mostram, entre os dados mais relevantes, que o livro estudado ainda dedica um espaço muito reduzido às atividades de ensino do sistema de escrita e não apresenta uma articulação satisfatória entre essas atividades e àquelas voltadas ao letramento, corroborando dados de outros estudos, aqui já mencionados. Esses resultados podem ser indicativos de que os critérios estipulados para a avaliação desses livros precisariam ser revistos de forma que atendessem mais equilibradamente tanto aos objetivos da alfabetização e do letramento quanto às necessidades da prática docente. Para um maior aprofundamento deste estudo considero que, futuramente, seus dados podem ser complementados por análises dos próprios docentes sobre o livro estudado, ou até mesmo por pesquisas sobre seu uso efetivo em sala de aula

中国暖温带森林群落多样性若干问题的研究

中国暖温带落叶阔叶林区维管植物共158科，931属，近4000种（含亚种，变种和变型），种子植物l3l科，877属，3770余种。暖温带植物区系有很强的温带性质，各类温带成分共548属，而各类热带成分仅226属，热带成分与温带成分(R/T)的比率为0．31。运用TWINSPAN和DCA对全国34个植物区系进行了数量分类排序，结果反映了一个地区的植物区系性质主要取决于其所在地的地理位置，同时也受山地海拔高度的强烈影响这一植物区系的基本特征。 根据暖温带森林植物的特点，修订了Raunkiear生活型系统。暖温带森林植物以地面芽植物(H)占较大的优势，占暖温带全部种类的33.9%;其次是地下芽(G)植物，占l 9.7%;全部高位芽植物占27.5%，绝大部分为落叶阔叶高位芽植物。主要由这些生活型组成的暖温带植物生活型总谱基本反映了暖温带夏季温暖多雨、冬季寒冷干旱的中纬度地区地面芽植物群落气候特征。 暖温带森林植被类型主要有7个植被亚型，约50个群系。辽东栎群落是典型的地带性森林群落。应用TWINSPAN和DCA程序将68块暖温带部分地区辽东栎群落样地和83块北京山区辽东栎群落样地分别划分为1 5个和14个群落类型。用物种丰富度指数、Simpson指数、多样性奇测法、Shannon-Wiene r指数、Pielou均匀度指数，Heip均匀度指数、AIatalo均匀度指数等常用的多样性测度方法，分别对暖温带和北京山区辽东栎群落的多样性进行了测度，结果发现，多样性作为一个整体与DCA第1轴有很大的相关关系：暖温带辽东栎群落多样性指数与DCA第1轴的复相关系数为0.7左右，北京山区较高，为0.8左右。多样性的空间特征为：随海拔的升高和纬度的降低，多样性指数呈上升趋势，反映了水热条件在辽东栎水平分布范围内、人类活动和水分因子在辽东栎垂直分布范围内对群落多样性的影响;不同群落之间多样性指数由低到高的顺序为：灌丛、辽东栎萌生丛、辽东栎林、辽东栎纯林、混交林，符合群落演替过程中多样性的动态规律。 对秦岭主峰太白山海拔1400-1600m之间植被类型和物种多样性进行了研究，在划分的1 5种群落类型中，以位于海拔1500-2300m之间的落叶阅叶混交林和栎类混交林的群落多样性最高，在海拔2300-3600m之间，群落多样性趋于单调下降，反映了热量的不足在这一海拔高度范围成为多样性的主要限制因子。

Classical plume theory: 1937-2010 and beyond

Developing a theoretical description of turbulent plumes, the likes of which may be seen rising above industrial chimneys, is a daunting thought. Plumes are ubiquitous on a wide range of scales in both the natural and the man-made environments. Examples that immediately come to mind are the vapour plumes above industrial smoke stacks or the ash plumes forming particle-laden clouds above an erupting volcano. However, plumes also occur where they are less visually apparent, such as the rising stream of warmair above a domestic radiator, of oil from a subsea blowout or, at a larger scale, of air above the so-called urban heat island. In many instances, not only the plume itself is of interest but also its influence on the environment as a whole through the process of entrainment. Zeldovich (1937, The asymptotic laws of freely-ascending convective flows. Zh. Eksp. Teor. Fiz., 7, 1463-1465 (in Russian)), Batchelor (1954, Heat convection and buoyancy effects in fluids. Q. J. R. Meteor. Soc., 80, 339-358) and Morton et al. (1956, Turbulent gravitational convection from maintained and instantaneous sources. Proc. R. Soc. Lond. A, 234, 1-23) laid the foundations for classical plume theory, a theoretical description that is elegant in its simplicity and yet encapsulates the complex turbulent engulfment of ambient fluid into the plume. Testament to the insight and approach developed in these early models of plumes is that the essential theory remains unchanged and is widely applied today. We describe the foundations of plume theory and link the theoretical developments with the measurements made in experiments necessary to close these models before discussing some recent developments in plume theory, including an approach which generalizes results obtained separately for the Boussinesq and the non-Boussinesq plume cases. The theory presented - despite its simplicity - has been very successful at describing and explaining the behaviour of plumes across the wide range of scales they are observed. We present solutions to the coupled set of ordinary differential equations (the plume conservation equations) that Morton et al. (1956) derived from the Navier-Stokes equations which govern fluid motion. In order to describe and contrast the bulk behaviour of rising plumes from general area sources, we present closed-form solutions to the plume conservation equations that were achieved by solving for the variation with height of Morton's non-dimensional flux parameter Γ - this single flux parameter gives a unique representation of the behaviour of steady plumes and enables a characterization of the different types of plume. We discuss advantages of solutions in this form before describing extensions to plume theory and suggesting directions for new research. © 2010 The Author. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved.

HPLC法测定野生与栽培藏药麻花艽中4种环烯醚萜苷类成分的含量

目的：对野生和栽培藏药麻花艽中龙胆苦苷、落干酸、獐牙菜苦苷和獐牙菜苷4种苦苷类成分进行高效液相色谱的含量测定，并比较分析它们之间的差异。方法：采用Eelipse XDB-C_8色潜柱(4.6 mm*150 mm，5 μm)，流动相A为95％乙腈水溶液，B为5％乙腈(含10 mmol•L~(-1)的甲酸)水溶液，A在0-20min内比例由0-100％进行线性洗脱，流速1.0 mL•min~(-1)，检测波长240 nm，柱温30℃。结果：4种成分均达到基线分离，龙胆菁苷、落干酸、獐牙菜苦苷、獐牙菜苷的线性范围分别为0.60～19•20μg(r=0.9999)，0.24～7.68μg(r=O.9999)，0.38-12.02μg(r=O.9999)，0.05～1.66μg(r=0.9999)；回收率分别为99.73％，98.13％，98.45％，96.22％。结论：栽培藏药麻花艽中苦苷类成分的含量已经接近或超过野生种的水平，可初步代替野生药材人药。

洱海沉积物孔隙水中溶解有机质的三维荧光光谱特征

文章应用三维荧光光谱技术对洱海沉积物孔隙水中的溶解有机质进行了研究。结果表明,所有样品均含有4个明显的荧光峰,其中A和C为类腐殖酸荧光,B和D为类蛋白荧光。荧光强度在沉积物-水界面特别强,在1cm处急剧下降,之后随着沉积深度呈上升趋势。孔隙水溶解有机质均具有强的类蛋白荧光,揭示了溶解有机质中含有大量色氨酸、酪氨酸等芳环结构的类蛋白物质,并且在早期成岩过程中随着沉积深度呈积累趋势;类蛋白荧光与类腐殖酸荧光之间具有一定的相关关系,r(A,C)值在0.94-1.79之间,随着沉积深度逐渐下降,r(D,B)值在0.9-1.75之间,与r(A,C)值极为接近,且随着沉积深度有着类似的变化趋势,说明在洱海沉积物孔隙

Characterization of interaction property of multicomponents in Chinese Herb with protein by microdialysis combined with HPLC

Interaction of traditional Chinese Herb Rhizoma Chuanxiong and protein was studied by microdialysis coupled with high performance liquid chromatography. Compounds in Rhizoma Chuanxiong, such as ferulic acid, senkyunolide A and 3-butylphthalide, were identified by HPLC, HPLC-MS and UV-vis. Microdialysis recoveries and binding degrees of compounds in Rhizoma Chuanxiong with human serum albumin (HSA) and other human plasma protein were determined: recoveries of microdialysis sampling ranged from 36.7 to 98.4% with R.S.D. below 3.1%; while binding to HSA ranged from 0 to 91.5% (0.3 mM HSA) and from 0 to 93.5% (0.6 mM HSA), respectively. Compared with HSA, most of compounds bound to human blood serum more extensively and the results showed that binding of these compounds in Rhizoma Chuanxiong was influenced by pH. Two compounds were found to bind to HSA and human blood serum. their binding degrees were consistent with ferulic acid and 3-butylphthalide, the active compounds in Rhizoma Chuanoxiong. (c) 2005 Elsevier B.V. All rights reserved.

SrTiO3(001)(2x1) reconstructions: First-principles calculations of surface energy and atomic structure compared with scanning tunneling microscopy images

(1x1) and (2x1) reconstructions of the (001) SrTiO3 surface were studied using the first-principles full-potential linear muffin-tin orbital method. Surface energies were calculated as a function of TiO2 chemical potential, oxygen partial pressure and temperature. The (1x1) unreconstructed surfaces were found to be energetically stable for many of the conditions considered. Under conditions of very low oxygen partial pressure the (2x1) Ti2O3 reconstruction [Martin R. Castell, Surf. Sci. 505, 1 (2002)] is stable. The question as to why STM images of the (1x1) surfaces have not been obtained was addressed by calculating charge densities for each surface. These suggest that the (2x1) reconstructions would be easier to image than the (1x1) surfaces. The possibility that the presence of oxygen vacancies would destabilise the (1x1) surfaces was also investigated. If the (1x1) surfaces are unstable then there exists the further possibility that the (2x1) DL-TiO2 reconstruction [Natasha Erdman Nature (London) 419, 55 (2002)] is stable in a TiO2-rich environment and for p(O2)>10(-18) atm.

Characterizing the marine Natura 2000 network for the Atlantic region

1. One of the goals for Natura 2000, a key European Community programme of nature conservation, is to produce a network of protected areas. An analysis of the Natura 2000 marine sites proposed in the most recently agreed list for the Atlantic region (northern Portugal to Denmark, n = 298) was used to characterize the network in terms of site areas and inter-site distances. Sites were considered as part of the network when they included any of the marine Natura 2000 Annex I habitat types found in the Atlantic region (excluding lagoons).

Strategies toward the design of energetic ionic liquids: nitro- and nitrile-substituted N,N '-dialkylimidazolium salts

Twelve novel 1,3-dialkylimidazolium salts containing strongly electron-withdrawing nitro-and cyano-functionalities directly appended to the cationic heterocyclic rings have been synthesized; the influences of the substituents on both formation and thermal properties of the resultant ionic liquids have been determined by DSC, TGA, and single crystal X-ray diffraction, showing that an electron-withdrawing nitro-substituent can be successfully appended and has a similar influence on the melting behaviour as that of corresponding methyl group substitution. Synthesis of di-, or trinitro-substituted 1,3-dialkylimidazolium cations was unsuccessful due to the resistance of dinitro-substituted imidazoles to undergo either N-alkylation or protonation, while 1-alkyl- 4,5-dicyanoimidazoles were successfully alkylated to obtain 1,3-dialkyl-4,5-dicyanoimidazolium salts. Five crystal structures ( one of each cation type) show that, in the solid state, the NO2-group has little significant effect, beyond the steric contribution, on the crystal packing.

Stable isotope analysis of archived roach (Rutilus rutilus) scales for retrospective study of shallow lake responses to nutrient reduction

1. There is increasing interest in the use of stable isotope analysis of archived materials to study the long-term impacts of lake perturbations, including nutrient manipulation or species invasion. We tested the utility of this approach in a shallow productive lake using the zooplanktivorous early life stages of roach ( Rutilus rutilus), a fish species that is widespread throughout Eurasian lakes.