Na2.44Mn1.79(SO4)(3): a new member of the alluaudite family of insertion compounds for sodium ion batteries

Sodium-ion batteries have been extensively pursued as economic alternatives to lithium-ion batteries. Investigating the polyanion chemistry, alluaudite structured Na2Fe2II(SO4)(3) has been recently discovered as a 3.8 V positive electrode material (Barpanda et al., Nature Commun., 5: 4358, 2014). Registering the highest ever Fe-III/Fe-II redox potential (vs. Na/Na+) and formidable energy density, it has opened up a new polyanion family for sodium batteries. Exploring the alluaudite family, here we report isotypical Na2+2xMn2-xII(SO4)(3) (x = 0.22) as a novel high-voltage cathode material for the first time. Following low-temperature (ca. 350 degrees C) solid-state synthesis, the structure of this new alluaudite compound has been solved adopting a monoclinic framework (s.g. C2/c) showing antiferromagnetic ordering at 3.4 K. Synergising experimental and ab initio DFT investigation, Na2+2xMn2-xII(SO4)(3) has been found to be a potential high-voltage (ca. 4.4 V) cathode material for sodium batteries.

Spectral characterizations and photophysical properties of one-step synthesized blue fluorescent 4 `-aryl substituted 2,2 `:6 `,2 `'-terpyridine for OLEDs application

We have synthesized a series of 4'-aryl substituted 2,2':6',2 `'-terpyridine (terpy) derivatives, namely 4'-(4-methylphenyl)-2,2':6',2 `'-terpyridine (C-1), 4'-(2-furyl)-2,2':6'2 `'-terpyridine (C-2), and 4'-(3,4,5-trimethoxyphenyl)-2,2':6',2 `'-terpyridine (C-3). The synthesized terpy compounds were characterized by elemental analyses, FTIR, NMR (H-1 and C-13), and ESI-Mass spectrometry. Photophysical, electrochemical and thermal properties of terpy compounds were systematically studied. Maximum excitation band was observed between 240 and 330 nm using UV-visible spectra, and maximum emission peaks from PL spectra were observed at 385, 405 and 440 nm for C-1, C-2 and C-3 respectively. Fluorescence lifetime (tau) of the fluorophores was found to be 035 and 1.55 ns at the excitation wavelength of 406 nm for C-1 and C-2 respectively, and tau value for C-3 was found to be 0.29 ns at the excitation wavelength of 468 nm. We noticed that the calculated values of HOMO energy levels were increased from 5.96 (C-1) to 6.08 (C-3) eV, which confirms that C-3 derivative is more electrons donating in nature. The calculated electrochemical band gaps were 2.95, 2.82 and 3.02 eV for C-1, C-2 and C-3 respectively. These blue fluorescent emitter derivatives can be used as an electron transport and electroluminescent material to design the blue fluorescent organic light emitting diode (OLED) applications. (C) 2015 Elsevier B.V: All rights reserved.

Positive isotropic curvature and self-duality in dimension 4

We study a positivity condition for the curvature of oriented Riemannian 4-manifolds: the half-PIC condition. It is a slight weakening of the positive isotropic curvature (PIC) condition introduced by M. Micallef and J. Moore. We observe that the half-PIC condition is preserved by the Ricci flow and satisfies a maximality property among all Ricci flow invariant positivity conditions on the curvature of oriented 4-manifolds. We also study some geometric and topological aspects of half-PIC manifolds.

E. U. Magisterio de Vitoria-Gasteiz. Plan general Practicum III. Comisión de prácticas, 4 de julio de 2014

[ES]Las Prácticas Escolares se realizarán en los dos ciclos de Educación Infantil (0-3, 3-6) y en los tres de Educación Primaria (1º-2º, 3º-4º, 5º-6º). Al tratarse de un Prácticum progresivo, cada estudiante cursa la materia a lo largo del segundo, tercer y cuarto curso (Prácticum I, Prácticum II y Prácticum III) con contenidos que tienen continuidad y que suponen un nivel de competencia superior respecto el anterior. Además, el alumnado que en 4º curso se matricule en el minor de Educación Física deberá realizar su periodo de prácticas junto a una maestra o maestro especialista en esta materia, quien tutorizará sus prácticas. El Prácticum supone para el alumnado una oportunidad de adquirir e integrar las habilidades, los conocimientos, las competencias y la práctica necesarios para el ejercicio de su profesión, así como una ocasión para reflexionar de forma individual y grupal acerca del aprendizaje realizado y de la práctica llevada a cabo.

Cr^4＋：YAG被动调QNd：YAG陶瓷激光器的研究

介绍了近几年迅速发展的一种新型激光介质——透明Nd：YAG多晶陶瓷的发展状况，对比分析了多晶陶瓷与单晶的光谱特性、激光特性和连续实验研究情况。并对钛宝石激光器调谐至808nm，端面抽运Nd：YAG陶瓷被动调Q全固态激光器的脉冲运转进行了较为详细的理论分析和实验研究。采用初始透射率为90％的Cr^4＋：YAG可饱和吸收晶体，被动调Q的阈值功率为119mW，当端面抽运功率为465mW时，获得波长为1064nm，脉宽为16ns，重复频率为18．18kHz，单脉冲能量为3．4μJ，平均输出功率为61mW的稳定调Q

Serie Vídeos tutoriales para fonética (volumen 2). Video 3. Lectura en voz alta

Esta es una colección de 6 vídeos tutoriales que pueden ser empleados como material educativo en los cursos de fonética en el ámbito universitario. Tratan principalmente del cómo se puede obtener información desde las palabras aisladas, como se observa en las técnicas de los vídeos 1-2, pasando por datos obtenidos con participación del investigador, característica aún presente en los vídeos 3-4, hasta enunciados íntegros sin necesidad del investigador presente, tal como se ilustra en los vídeos 5-6. Se trata de establecer una reflexión entre la necesidad de identificar el grado de espontaneidad a la hora de brindar información por parte del hablante y la posibilidad (o la necesidad) de cuantificar los datos que se obtienen.

Serie Vídeos tutoriales para fonética (volumen 2). Video 4. Entrevista semidirigida

Esta es una colección de 6 vídeos tutoriales que pueden ser empleados como material educativo en los cursos de fonética en el ámbito universitario. Tratan principalmente del cómo se puede obtener información desde las palabras aisladas, como se observa en las técnicas de los vídeos 1-2, pasando por datos obtenidos con participación del investigador, característica aún presente en los vídeos 3-4, hasta enunciados íntegros sin necesidad del investigador presente, tal como se ilustra en los vídeos 5-6. Se trata de establecer una reflexión entre la necesidad de identificar el grado de espontaneidad a la hora de brindar información por parte del hablante y la posibilidad (o la necesidad) de cuantificar los datos que se obtienen.

Wissenschaftler empfehlen 1978er Fangquoten für ICNAF-Gebiete 0 bis 4

Tagung des ICNAF-Assessments Subcommittee vom 19. bis 27. April 1977 in Dartmouth/KANADA

Ag~+-Li~+离子交换制作Er~(3+)/Yb~(3+)共掺磷酸盐玻璃平面光波导(英文)

制备了化学稳定的Er^3＋／Yb^3＋共掺的磷酸盐玻璃，并在其中制作了用于光放大器和激光器的平面光波导．这种磷酸盐玻璃的失重速率为4．7×10^-5g·cm^-2·hr^-1，小于Kigre公司商业化的磷酸盐玻璃QX／Er的失重速率．采用Ag^＋-Li^＋交换技术制作了平面光波导并用m-线光谱在632．8nm测量了平面光波导的有效折射率．根据反WKB法得到折射率形貌，计算了离子交换参数如：离子交换深度、表面折射率，折射率改变和扩散系数等．

Structural and up-conversion luminescence properties in Tm (3+)/Yb3+-codoped heavy metal oxide-halide glasses

Tm3+/Yb3+-codoped heavy metal oxide-halide glasses have been synthesized by conventional melting and quenching method. Structural properties were obtained based on the Raman spectra, indicating that halide ion has an important influence on the phonon density and maximum phonon energy of host glasses. Intense blue and weak red emissions centered at 477 and 650 nm, corresponding to the transitions (1)G(4) -> H-3(6) and (1)G(4) -> H-3(4), respectively, were observed at room temperature. The possible up-conversion mechanisms are discussed and estimated. With increasing halide content, the up-conversion luminescence intensity and blue luminescence lifetimes of Tm3+ ion increase notably. Our results show that with the substitution of halide ion for oxygen ion, the decrease of phonon density and maximum phonon energy of host glasses both contribute to the enhanced up-conversion emissions. (c) 2005 Elsevier B.V. All rights reserved.

Judd-Ofelt analysis of spectra and experimental evaluation of laser performance of Tm3+ doped Lu2SiO5 crystal

This paper reports that the TM3+:Lu2SiO5 (Tm:LSO) crystal is grown by Czochralski technique. The room-temperature absorption spectra of Tm:LSO crystal are measured on a b-cut sample with 4 at.% thulium. According to the obtained Judd-Ofelt intensity parameters Omega(2)=9.3155 x 10(-20) cm(2), Omega(4)=8.4103 x 10(-20) cm(2), Omega(6)=1.5908 x 10(-20) cm(2), the fluorescence lifetime is calculated to be 2.03 ms for F-3(4) -> H-3(6) transition, and the integrated emission cross section is 5.81 x 10(-18) cm(2). Room-temperature laser action near 2 mu m under diode pumping is experimentally evaluated in Tm:LSO. An optical-optical conversion efficiency of 9.1% and a slope efficiency of 16.2% are obtained with continuous-wave maximum output power of 0.67 W. The emission wavelengths of Tm:LSO laser are centred around 2.06 mu m with spectral bandwidth of similar to 13.6 nm.

Bulk crystal growth and efficient diode-pumped laser performance of Yb 3+:Sc2SiO5

A bulk crystal of Yb:Sc2SiO5 (Yb:SSO) with favorable thermal properties was successfully obtained by the Czochralski method. The energy level diagrams for Yb:SSO crystal were determined by optical spectroscopic analysis and semi-empirical crystal-field calculations using the simple overlap model. The full width at half maximum of the absorption band centering at 976 nm was calculated to be 24 nm with a peak absorption cross-section of 9.2x10(-21) cm(2). The largest ground-state splitting of Yb3+ ions is up to 1027 cm(-1) in a SSO crystal host. Efficient diode-pumped laser performance of Yb:SSO was primarily demonstrated with a slope efficiency of 45% and output power of 3.55 W.

Biologie de Penaeus duorarum notialis en Côte d'Ivoire. 4 - Rélations entre la répartition et les conditions du milieu. Étude des variations du sex-ratio

The analysis of the geographic and bathymetric distribution of Penaeus duorarum and, particularly P. d. notialis off Côte d'Ivoire and in its whole distribution area leads to the definition of the adult ecological requirements (temperature, salinity, grain size and sediment composition, organic matter) and the importance of the thermocline in the bathmetric distribution. The population structure study shows: (1) variations of size with depth, (2) variations of sex ratio, with size, depth and seasons.

水稻RAD21/REC8家族基因OsRAD21-3的功能研究

有丝分裂和减数分裂包含一系列协同作用的事件，姊妹染色体的黏着是其中非常重要的一个环节。通过对芽殖酵母的研究发现姊妹染色体的黏着是由一个多亚基的蛋白复合体——黏着素介导的，在有丝分裂过程中，黏着素由Scc1（裂殖酵母中为Rad21）、Scc3、Smc1和Smc3四个亚基组成，而在减数分裂中Scc1被其同源蛋白Rec8所取代。通过对其它真核生物包括线虫、果蝇、爪蟾、鼠、人以及拟南芥等进行的研究显示，黏着素介导的姊妹染色体黏着的基本机制在真核生物中具有保守性，但在不同的物种中，其具体的分子机制还存在着差异。开花植物的有性生殖过程包含了一个非常特殊的花粉发育阶段，其间发生了两次花粉的有丝分裂，对其我们还知之甚少。Rad21/Rec8作为黏着素的重要组分，对水稻中它的同源蛋白进行深入研究可以帮助我们对植物有丝分裂和减数分裂的染色体黏着机制有进一步的了解。 我们发现在水稻基因组中存在4个编码Rad21/Rec8家族蛋白的基因，其中OsRAD21-3位于水稻第8号染色体上，其编码的蛋白与其它的Rad21/Rec8家族蛋白一样，具有保守的N-和C-末端结构域。序列比对和进化分析的结果表明OsRad21-3蛋白属于Rad21亚家族，而免疫荧光定位分析显示OsRad21-3可以特异地定位于有丝分裂的染色体上，由此说明OsRAD21-3应当是酵母RAD21的直系同源基因。对OsRAD21-3进行半定量RT-PCR，Western杂交以及原位杂交的结果显示它在生殖器官花中优势表达，在营养器官中也能检测到表达。在花中它在从雌雄蕊形成期到成熟花粉期都有表达，其表达的位置主要位于减数分裂时期的小孢子母细胞以及减数分裂后的小孢子和花粉中。在水稻四个RAD21/REC8基因中，OsRAD21-3是唯一一个在花粉发育过程中表达的基因，说明它可能在减数分裂后的雄配子体发育过程中发挥了功能。 采用RNAi手段对OsRAD21-3的功能进行研究发现OsRAD21-3 RNAi转基因水稻植株的育性显著下降，进一步的分析表明其花粉活性受到严重影响。对OsRAD21-3i株系的雄性减数分裂过程及减数分裂后的小孢子和花粉发育过程进行观察发现，减数分裂过程中有少量细胞存在染色体的异常行为，但总体上没有对雄性减数分裂造成严重影响，而减数分裂后的小孢子和花粉发育过程则出现了显著异常，表现为花粉有丝分裂的停滞或有丝分裂染色体分离的扰乱，因此，OsRAD21-3应当主要是通过在花粉的有丝分裂过程中发挥功能而参与减数分裂后的雄配子体发育过程，而它在雄性减数分裂过程中可能也有一定作用。 利用原位杂交技术分析了水稻另外三个RAD21/REC8基因的表达特性，结果表明OsRAD21-1、OsRAD21-2和OsRAD21-4都在减数分裂前及减数分裂期的小孢子母细胞中表达，但在减数分裂后较晚时期的小孢子中则没有检测到表达。OsRAD21-4在小孢子母细胞中的表达为其参与减数分裂过程染色体的黏着提供了证据，而OsRAD21-1和OsRAD21-2在此过程中的功能还有待进一步研究。此外，OsRAD21-1和OsRAD21-2还在营养器官有丝分裂旺盛的区域表达，OsRAD21-1作为RAD21的同源基因可能与OsRAD21-3在参与有丝分裂染色体黏着方面存在功能上的冗余性，但OsRAD21-3参与花粉的发育过程则是其所特有的，这可能也在一定程度上说明了为什么水稻中会存在4个RAD21/REC8基因，并帮助我们更好地了解了它们在功能上的分化。

Sox2基因3'非翻译区保守元件对基因表达的调控作用

转录因子Sox2是脊椎动物早期发育中最早表达的神经系统特异性基因之一,同时在干细胞的维持中也起着关键作用.通过生物信息学分析,作者发现在脊椎动物Sox2 mRNA 3'非翻译区中存在4段非常保守的富含AU的区域.将这些片段按照不同的组合克隆到GFP和荧光素酶两种报告基因载体中,在非洲爪蟾胚胎和培养细胞中检测了这些片段对报告基因表达的影响.结果显示,Sox2的3'UTR可影响报告基因的表达水平,特别是其中的保守片段2可显著提高报告基因的表达水平,表明Sox2 3'非翻译区有可能参与Sox2表达的转录后调控.