Photoluminescence of BaGdB9O（16）：Eu^3＋ co-doped Al^3＋ or Sc^3＋ under UV-VUV excitation

Single phase of BaGd0.9-xMxEu0.1B9O16 (M=Al or Sc, 0≤x≤0.3) powder was prepared by the solid-state reaction and its photoluminescence (PL) properties were investigated under ultraviolet (UV) and vacuum ultraviolet (VUV) excitation. Monitored with 613 nm emission, the excitation spectra of BaGd0.9-xMxEu0.1B9O16 consisted of three broad bands peaking at about 242, 208, and 142 nm, respectively. The one at about 242 nm originated from the charge transfer band (CTB) of O2-→Eu3+. The other two were assigned to the absorption of the host, which was overlapped with absorptions among borate groups, f→d transition of RE3+ (RE=Gd, Eu), and the charge transfer transition of O2-→Gd3+. The maximum emission peak was observed at about 613 nm in the emission spectra of BaGd0.9-xMxEu0.1B9O16 under both 254 and 147 nm excitation, which originated from the electric dipole 5D0→7F2 transition of Eu3+. When excited with 254 nm, the integral emission intensity of Eu3+ increased after Al3+ or Sc3+ substituting Gd3+ partly in BaGd0.9Eu0.1B9O16. Under 147 nm excitation, the integral emission intensity of Eu3+ decreased after some Gd3+ was replaced by Sc3+, but increased after adding appropriate Al3+ into BaGd0.9Eu0.1B9O16.     

MnO_x-CeO_2为电催化剂的氧还原阴极的性能研究

CeO_2是很好的富集氧材料,MnO_2有较好的氧还原电催化性能。以硝酸锰和硝酸铈为原料,通过水热法制备均匀的MnO_x-CeO_2复合金属氧化物。通过XRD物相和晶相分析,阴极极化曲线等手段,研究了以MnO_x-CeO_2复合金属氧化物为电催化剂的氧电极的电催化氧还原性能,确定了MnO_x-CeO_2复合金属氧化物的最佳配比和烧结温度。实验结果表明,用水热法合成MnO_x-CeO_2复合金属氧化物时,当n(Mn)/n(Ce)=1∶0.6时,350℃烧结5 h后,MnO_2进入萤石型CeO_2中形成MnO_x-CeO_2复合金属氧化物,与MnO_2相比,具有更好的富氧能力,电催化氧还原性能也更好。     

Li2ZrO3包覆锂离子电池正极材料Li[Li0.2Ni0.2Mn0.6]O2的制备及其电化学性能

富锂锰基材料因其具有较高的充放电比容量而备受关注。针对其首次库仑效率低、循环和倍率性能差的问题,将具有三维Li^+通道的锂离子导体Li2ZrO3引入至富锂锰基正极材料Li[Li0.2Ni0.2Mn0.6]O2的表面对其进行包覆改性研究。通过XRD,TEM,SEM,EDS综合分析可知:Li2ZrO3成功包覆到样品表面。包覆层厚度为3 nm(包覆量1%,质量分数)时复合材料的电化学性能得到显著提升。0.1 C(1 C=200 mAh·g^-1)倍率下首次放电比容量可达271.5 mAh·g^-1,库仑效率为72.4%,降低了首次不可逆容量损失;0.5 C下循环100周次后放电比容量为191.5 mAh·g^-1,容量保持率为89.5%,5 C倍率放电比容量为75 mAh·g^-1,倍率性能提升。适当厚度的均匀Li2ZrO3包覆层可在样品表面形成核壳结构使样品更稳定,减少表面副反应,阻止生成较厚SEI膜,这得益于Li2ZrO3本身的高电导率、高电化学稳定性和较好的锂离子传导性。     

A novel un-doped long lasting phosphorescence phosphor:SrZrSi2O7

A novel phosphor of un-doped Sr Zr Si2O7 material with blue long lasting phosphorescence which could be recorded for about 5400 s(0.32 mcd/m2) was developed. It revealed that both the emission centers and traps levels were related to the oxygen-deficient defects which were induced in reducing atmosphere. The filling and fading experiments indicated that the traps levels in Sr Zr Si2O7 were continuous in distribution. The influence of shallow traps on deep traps was investigated and the important role of the bridge effect was revealed. The un-doped Sr Zr Si2O7 material obtained in reducing atmosphere showed potential application as a cheap blue long lasting phosphorescence phosphor.     

（Y，Bi，Sc）VO4：Eu^3＋的制备及其发光特性

用高温固相法在900℃，保温6h的条件下制备了YVO4单相粉末样品。在紫外光254nm激发下，YVO4：Eu^3＋的激发光谱由VO4^3＋的吸收带和Eu^3＋的电荷迁移带组成。发射光谱为Eu^3＋的^5D0→^7Fj（J=1,2，4）跃迁。在Eu^3＋含量一定的情况下掺杂Bi^3＋和sc^3＋，随着Bi^3＋浓度的增加，激发光谱宽化，但发射强度变弱；SC^3＋浓度的增加则使YVo4：Eu^3＋的发射强度先增加后降低。在147nm激发下，（Y,Bi，Sc）VO4：Eu^3＋的发射光谱相对于YVO4：Eu^3＋有降低趋势。     

数字式MRH主令控制器和S形速度曲线的原理

在现代化冷轧带钢连续处理线上（如连续退火机组）,生产线上的辅助辊几乎全部采用主动辊来传动。当整条机组在升速或降速时,为了使所有传动辊速度同步,必须采用ＭＲＨ主令速度控制器。同时为了减少机组加减速时各传动辊间带钢张力和的波动,指令速度曲线必须无折角并呈光滑的Ｓ形状。对数字式ＭＲＨ及Ｓ形速度曲线的原理与实现方法作了概要介绍。     

BaMgAl10O17:Eu2+的硝酸盐热分解法合成及其发光特性研究

以Ba(NO3)2、Al(NO3)3·9H2O、Mg(NO3)2·6H2O和Eu(NO3)3为初始原料,首次用硝酸盐热分解法在1300℃左右合成了单相Ba1-xMgAl10O17xEu2+(0.02≤x≤0.16)并表征了其发光特性.结果表明,硝酸盐热分解法的合成温度比传统的高温固相法降低了近300℃,且合成出的荧光粉体色白、亮度好、结构松散且无烧结现象.在254 nm紫外光激发下,Ba1-xEuxMgAl10O17(0.02≤x≤0.16)的最强峰在450 nm左右,属于Eu2+的4f65d→4f7(8S7/2)宽带允许跃迁;当x=0.1时发光强度最高.用硝酸盐热分解法合成的样品较传统高温固相法所得样品的发光强度强.     

CaSiO3:Mn,Pb-B2O3系化合物的合成及其UV和VUV发光特性

以CaSiO3-B2O3系化合物为研究对象、Mn作为发光中心,探索了其作为高亮度发光材料的可能性.用高温固相法于1150℃、3h、N2气氛下合成了CaSiO3:0.066Mn,0.008Pb-B2O3系列单相粉末样品并研究了其发光特性.结果表明,当B/(B Si)质量比≤0.3时样品为β-CaSiO3单相,随着B2O3含量的变化,没有观察到X射线住置的明显变化,这说明B的固容量有限.当B/(B Si)质量比>0.3时发现有杂质相.在254nm激发下,观察到最大强度位于617nm的红色发射峰且B/(B Si)质量比=0.3时达到最大.147nm真空紫外激发下的发射峰和紫外激发下的一致,发射强度也在B/(B Si)质量比=0.3时达到最大;617nm监控下的VUV激发光谱由峰值位于185和253nm的两个激发带构成,分别归属于基质吸收和激活离子激发.     

红色蓄光材料Y2O2S:Eu3+的硫熔法制备及其发光性能

用硫熔法制备了系列红色蓄光材料Y2O2S ：Eux^3＋（0．01≤x≤0．10）的多晶粉末样品并系统研究了其发光特性。XRD结果表明,晶胞参数c随着Eu^3＋含量的逐渐增大而增大,而晶胞参数α没有明显的线性变化关系,这与Y2O2S ：Eu^3＋的晶体结构有关。Y2O2S ：Eux^3＋（0．01≤x≤0．10）的激发光谱相似,在626nm发射光监控下最大激发波长约在330nm附近。在330nm激发下,随着Eu^3＋含量逐渐增大,发射光谱最强发射峰位置从540nm右移至626nm,观察到红色特征发射峰626nm的强度逐渐增大,在Eu^3＋含量为0．09时,其强度达到最大。在最佳合成条件及最佳Eu^3＋含量下,正在进行掺杂Mg^2＋和Ti^4＋及其发光特性的研究。     

2030冷连轧机的道次计算

轧机道次计算是连轧机设定计算中最主要的项目。最佳地选择轧制方式和正确计算各机架压下量和速度,能确保安全与高速轧制。道次计算包括轧制方式选择,设定值计算,测量值收集和处理及模型公式的自适应和自学习。