余庚华
,
仲嘉琪
,
王谨
,
詹明生
量子电子学报
doi:10.3969/j.issn.1007-5461.2012.03.001
Ba原子是光频标的候选者之一,对其进行有效的激光冷却与囚禁需要相关能级的寿命和跃迁几率的信息.Ba原子激发态6s6p3P1能级在激光冷却实验中很重要,通过Hanle效应实验测量了这一能级的寿命和自发辐射率,从理论和实验上研究了探测激光有限线宽和光强对Ba原子基态6s21S0与激发态6s6p3P1之间跃迁(波长791nm)Hanle效应荧光信号的影响.在考虑了激光线宽和光强因素后所得到的激发态6s6p3P1的能级寿命和自发辐射率与其他方法给出的结果符合很好.
关键词:
光谱学
,
能级寿命
,
Hanle效应
,
线宽
,
Ba原子
,
原子频标
马保国
,
许婵娟
,
钟开红
,
蹇守卫
,
李相国
材料科学与工程学报
doi:10.3969/j.issn.1673-2812.2005.04.006
本文系统地研究了F、S、P元素对水泥熟料矿物形成过程和组成的影响及其叠加矿化效应,并通过化学分析和XRD分析探讨了其作用机理.研究结果表明:F、S、P元素在水泥烧成中均可降低液相出现和C3S形成温度,改善易烧性,但F、S叠加矿化效果最好,而且可以改善熟料的矿物组成及性能,避免了单掺F造成的熟料活性降低等问题.
关键词:
矿化效应
,
氟石膏
,
磷石膏
,
易烧性
张玉荣
,
陈宇
功能材料
以LiTi2(PO4)3为母体,以天然高岭石为起始原料,经高温固相反应制得了一系列新的锂快离子导体Li1.2+x-yAl0.1+xTi1.9-xSi0.1SyP2.9-yO12(以下简称Al-S-Lisicon).X射线粉末衍射分析结果表明在x≤0.30,y＜0.2+x的组成范围内均能得到类似于Nasicon三方结构的相.应用交流阻抗技术测定电导率的结果表明起始组成为x=0.20,y=0.20的合成物电导率最高,室温下为6.01×10-5S/cm,573K时达1.11×10-2S/cm,其在373～573K间的活化能为28.6kJ/mol,分解电压为3.1V.
关键词:
矿物锂快离子导体
,
Al-S-Lisicon
,
高岭石
陈宇
,
张玉荣
中国稀土学报
以LiTi2(PO4)3为母体,以天然高岭石为起始原料,经高温固相反应制得了一系列新的锂快离子导体Li1.2+x-yYxTi1.9-xAl0.1Si0.1SyP2.9-yO12(以下简称Y-S-Lisicon).X射线粉末衍射分析结果表明在x≤0.3,y＜(0.2+x)的组成范围内均能得到类似于Nasicon三方结构的相,同时还存在其他杂相.应用交流阻抗技术测定电导率的结果表明起始组成为x=0.1,y＝0.15的合成物电导率最高,其在室温下的电导率为2.93×10-5 S·cm-1,在673 K时可达3.62×10-2 S·cm-1,其在473～673 K间的活化能为37.19 kJ·mol-1,分解电压为3.0 V.
关键词:
矿物锂快离子导体
,
Y-S-Lisicon
,
高岭石
,
稀土
材料科学技术（英文）
The doping of phosphorus, sulfur and boron in IN718 superalloy can remarkably influence the creep behavior. The modifications of the minor elements seem not to vary the stress exponent and the influences primarily concentrate on the effective diffusion coefficient. A pronounced beneficial interaction between P and B and a weaker detrimental interaction between P and S have been obtained. The preexponential frequency constant is proved to be strongly related with the creep activation energy because of the so-called compensation effect. The compensation temperature has been determined to be about 1080 K, which corresponds to the transformation temperature from rapidly coarsened gamma " phase to delta phase. It has been proposed that trace elements can influence the effective diffusion coefficient individually or cooperatively, which in turn either retard or speed the creep process.
关键词:
Energy & Environmental Science
We report the template-directed synthesis of sulphur-carbon nanotubes and their use to form a membrane that is binder-free, highly conductive and flexible. This nanostructured membrane is used as a self-supporting cathode without metal current-collectors for Li-S batteries. The membrane cathode has a high electrical conductivity and renders a long life of sulphur of over 100 charge-discharge cycles. High discharge capacity of sulphur was attained at 712 mA h g(sulphur)(-1) (23 wt% S) and 520 mA h g(sulphur)(-1) (50 wt% S) at a high current density (6 A g(sulphur)(-1)). The overall capacity of the flexible cathode correspondingly reaches 163 mA h g(-1) (23 wt% S) and 260 mA h g(-1) (50 wt% S). These results demonstrate the great potential of this nanostructured flexible membrane as a cathode for Li-S batteries with fast charge-discharge performance and long life.
关键词:
rechargeable lithium batteries;positive electrode materials;cell;temperature;composites;capacity;oxide
