Microwave Dielectric Resonator Based on Ba[(Bi0.2 D3+0.3)Nb0.5]O3(D3+=Y,Pr,Sm,Gd,Dy,Er)

Dielectric resonator ceramics with composition formula Ba[(D3+0.3 Bi0.2)Nb0.5]O3,where D3+=Y,Pr,Sm,Gd,Dy and Er,were prepared by the conventional ceramic preparation route

Preparation, Characterization, and Microwave Properties of RETiNbO6 (RE = Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Y, and Yb) Dielectric Ceramics

Microwave ceramic dielectric resonators (DRs) based on RETiNbO6 (RE = Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Y, and Yb) have been prepared using the conventional solid -state ceramic route. The DR samples are characterized using XRD and SEM methods. The microwave dielectric properties are measured using resonant methods and a net work analyzer . The ceramics based on Ce, Pr, Nd, and Sin have dielectric constants in the range 32-54 and positive coefficient of thermal variation of resonant frequency (r,). The ceramics based on Gd, Tb, Dy, Y. and Yb have dielectric constants in the range 19-22 and negative Tf

Microwave Dielectric Properties of RETiTaO6 (RE = La, Ce,Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Er, Yb, Al, and In) Ceramics

Microwave dielectric ceramics based on RETiTaO6 (RE = La, Cc, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Er, Yb, Al, and In) were prepared using a conventional solid-state ceramic route. The structure and microstructure of the samples were analyzed using x-ray diffraction and scanning electron microscopy techniques. The sintered samples were characterized in the microwave frequency region. The ceramics based on Ce, Pr, Nd, Sm, Eu, Gd, Tb, and Dy, which crystallize in orthorhombic aeschynite structure, had a relatively high dielectric constant and positive T f while those based on Ho, Er, and Yb, with orthorhombic euxenite structure, had a low dielectric constant and negative Tf. The RETiTaO6 ceramics had a high-quality factor. The dielectric constant and unit cell volume of the ceramics increased with an increase in ionic radius of the rare-earth ions, but density decreased with it. The value of Tf increased with an increase in RE ionic radii, and a change in the sign of Tf occurred when the ionic radius was between 0.90 and 0.92 A. The results indicated that the boundary of the aeschynite to euxenite morphotropic phase change lay between DyTiTaO6 and HoTiTaO6. Low-loss ceramics like ErTiTaO6 (Er = 20.6, Qxf = 85,500), EuTiTaO6 (Er = 41.3, Qxf = 59,500), and YTiTaO6 (Er = 22.1, Q„xf = 51,400) are potential candidates for dielectric resonator applications

Preparation, Characterization and Microwave Dielectric Properties of Ba (B1/2Nb1/2)03 [B' = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Yb and In] Ceramics

Microwave dielectric resonators (DRs) based on Ba(B1,2Nbi/2)03 [B' = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Yb, and In] complex perovskites have been prepared by conventional solid state ceramic route. The dielectric properties (relative permittivity, Er; quality factor, Q; and resonant frequency, rr) of the ceramics have been measured in the frequency range 4-6 GHz using resonance methods. The resonators have relatively high dielectric constant in the range 36-45, high quality factor and small temperature variation of resonant frequency. The dielectric properties are found to depend on the tolerance factor (t), ionic radius (r), and lattice parameter (ap)

A study of the white electroluminescence in ZnS:Cu,Pr,Cl phosphors

The method of preparation of ZnS phosphors doped with praseodymium and copper is given. The electroluminescence (EL) spectrum of ZnS:Pr,Cl has two broad bands at 470 and 570 nm. ZnS:Cu,Pr,Cl gives white emission with spectral peaks at 470, 520, 570 and 640 nm. The EL spectra of both types of phosphor exhibit a conspicuous colour shift as the frequency of the excitation voltage is varied. Detailed investigations show that the relative intensities of spectral peaks are strongly dependent on the frequency of the excitation voltage. The colour shift is explained on the basis of the Schon-Klasens model.

Temperature dependent polarized Raman spectra of nonaaqualanthanoid (Pr) single crystal

Polarized Raman spectral changes with respect to temperature were investigated for Pr(BrO3)3·9H2O single crystals. FTIR spectra of hydrated and deuterated analogues were also recorded and analysed. Temperature dependent Raman spectral variation have been explained with the help of the thermograms recorded for the crystal. Factor group analysis could propose the appearance ofBrO3 ions at sites corresponding to C3v (4) and D3h (2). Analysis of the vibrational bands at room temperature confirms a distorted C3v symmetry for the BrO3 ion in the crystal. From the vibrations of water molecules, hydrogen bonds of varying strengths have also been identified in the crystal. The appearance υ1 mode of BrO3− anion at lower wavenumber region is attributed to the attachment of hydrogen atoms to the BrO3− anion. At high temperatures, structural rearrangement is taking place for bothH2Omolecule and BrO3 ions leading to the loss ofwater molecules and structural reorientation of bromate ions causing phase transition of the crystal at the temperature of 447 K.

Swamp buffalo keeping – an out-dated farming activity? A case study in smallholder farming systems in Xishuangbanna, Yunnan Province, PR China

Expansion of rubber tree plantations and agricultural mechanization caused a decline of swamp buffalo numbers in the Naban River National Nature Reserve (NRNNR), Yunnan Province, China. We analysed current use of buffaloes for field work and the recent development of the regional buffalo population, based on interviews with 184 farmers in 2007/2008 and discussions with 62 buffalo keepers in 2009. Three types of NRNNR farms were distinguished, differing mainly in altitude, area under rubber, and involvement in livestock husbandry. While pig based farms (PB; n=37) have abandoned buffalo keeping, 11% of the rubber based farms (RB; n=71) and 100% of the livestock-corn based farms (LB; n=76) kept buffaloes in 2008. Herd size was 2.5 +/-1.80 (n=84) buffaloes in early 2008 and 2.2 +/-1.69 (n=62) in 2009. Field work on own land was the main reason for keeping buffaloes (87.3 %), but lending work buffaloes to neighbours (79.0%) was also important. Other purposes were transport of goods (16.1%), buffalo trade (11.3%) and meat consumption (6.4%). Buffalo care required 6.2 +/-3.00 working hours daily, while annual working time of a buffalo was 294 +/-216.6 hours. The area ploughed with buffaloes remained constant during the past 10 years despite an expansion of land cropped per farm. Although further replacement of buffaloes by tractors occurs rapidly, buffaloes still provide cheap work force and buffer risks on poor NRNNR farms. Appropriate advice is needed for improved breeding management to increase the efficiency of buffalo husbandry and provide better opportunities for buffalo meat sale in the region.

Organizaci??n y puesta en pr??ctica de actividades l??dicas de gran grupo en la escuela

Se presenta experiencia educativa que propone una reuni??n quincenal entre el profesorado para organizar las actividades del centro. Se realiza en el CEIP Dolores Romero Pozo en Cenes de la Vega, Granada. Los objetivos son: organizar actividades l??dicas para 'gran grupo'; hacer part??cipes a todos los miembros de la comunidad educativa de esas actividades; crear un clima facilitador de la convivencia.

La atenci??n a la diversidad de nuestro alumnado como variable de disminuci??n del fracaso escolar : una propuesta pr??ctica

Se pretende paliar el absentismo y el abandono escolar prematuro y poner al alcance de todo el alumnado los elementos del curriculum de forma que, desde la integraci??n, todas y todos vivan su tiempo de escolarizaci??n como un tiempo ??til, sin desesperanza y con las perspectivas de obtener el Graduado de ESO.

La pr??ctica administrativa en los documentos de evaluaci??n y movilidad del alumnado

Documento dirigido a los equipos directivos de los institutos de Ense??anza Secundaria y al personal vinculado a sus secretar??as cuyo objetivo es servir de ayuda en la complejidad que genera la implantaci??n de los nuevos planes de estudios y su coexistencia con los anteriores y conseguir con ello un mejor conocimiento y cumplimentaci??n de los documentos oficiales de evaluaci??n en la ESO y una correcta formalizaci??n de las matr??culas de los alumnos propios o colegiados que se incorporen a ense??anzas reguladas por la LOGSE. Est?? estructurado en tres cap??tulos y un apartado de supuestos pr??cticos. El primero, dedicado a la documentaci??n relativa a la Educaci??n Secundaria, ofrece un recorrido minucioso por la normativa reguladora de la evaluaci??n en esta etapa. En el segundo y tercer cap??tulos se abordan los aspectos m??s significativos al proceso de matriculaci??n de los alumnos que transitan desde el sistema educativo que se extingue al sistema educativo derivado de la LOGSE y viceversa. El ??ltimo apartado presenta una serie de supuestos pr??cticos, resueltos los m??s significativos, confiri??ndole un sentido pr??ctico y funcional a los aspectos tratados en los cap??tulos anteriores.

La ense??anza y el aprendizaje de las personas adultas (nivel 1) : el curr??culum en la pr??ctica

Recopilaci??n de ponencias y comunicaciones realizadas dentro de un proyecto establecido en el Seminario Provincial de profesores de Personas Adultas, celebrado en Murcia en 1995. La idea fundamental es extraer conclusiones e informaci??n necesaria para conocer logros, carencias y necesidades por alcanzar y, de esta forma, iniciar nuevas din??micas de trabajo y planteamientos. La publicaci??n analiza el dise??o de un proceso de comunicaci??n en la realidad de la ense??anza-aprendizaje de las personas adultas de nivel I, conocimiento compartido de la lengua escrita y hablada con sus estrategias de adquisici??n y desarrollo.

Realidad y diversidad : desde una concepci??n ideol??gica a una pr??ctica ??tica : t??cticas y estrategias para una educaci??n sin exclusi??n

El libro sin pr??logo ni introducci??n, se organiza a modo de manual de texto para los alumnos de las facultades de educaci??n y de los de formaci??n del profesorado, en ??l se abordan los problemas de atenci??n a la diversidaden los centros docentes desde los puntos de vista organizativo y curricular hasta los ideol??gicos y ??ticos. Tambi??n se hace referencia al papel del asesoramiento y el apoyo pedag??gico en la formaci??n del profesorado, autismo y educaci??n y el aprendizaje cooperativo.

Geograf??a, profesorado y sociedad : teor??a y pr??ctica de la geograf??a en la ense??anza

Organizan: Asociaci??n de Ge??grafos Espa??oles; Departamento de Geograf??a F??sica, Humana y An??lisis Geogr??fico Regional de la Universidad de Murcia y la Consejer??a de Educaci??n y Universidades de la Regi??n de Murcia

Estrategias de intervenci??n social en el ??mbito educativo : modelo de pr??ctica profesional dirigido a alumnos con necesidades educativas especiales

Manual para trabajadores sociales que desarrollen su actividad en el ??mbito educativo. El libro se estructura en tres partes, una primera parte en la que se da a conocer las funciones del trabajador social en los centros educativos, un segundo bloque con todos los proyectos de intervenci??n que configuran el eje de actuaci??n del trabajador social en los centros educativos, as?? como dos protocolos b??sicos, uno de aplicaci??n en situaciones de higiene personal deficitaria y un segundo de aplicaci??n en situaciones de absentismo escolar y un tercer bloque que recoge todos los instrumentos y t??cnicas de trabajo para desarrollar dichos proyectos.

Manual de pr??cticas de Bot??nica

Cuaderno de trabajo cuyo objetivo es convertirse en un instrumento que posibilite realizar pr??cticas de bot??nica. Est?? orientado a la investigaci??n did??ctica centr??ndose fundamentalmente en trabajos de clasificaci??n, observaci??n y comprobaci??n de leyes, experiencias motivantes para el profesor en su aproximaci??n al estudio de los vegetales. Cada una de las experiencias est?? estructurada en un planteamiento de objetivos, relaci??n de material a utilizar, esquema o dibujo de la experiencia, desarrollo de la misma en pasos claros y una serie de propuestas de post-actividades. La dificultad en la realizaci??n va en orden creciente, facilitando la operatividad de aprendizaje en los distintos niveles educativos desde el ??ltimo ciclo de Primaria hasta la Educaci??n Secundaria.