Sang-Min Jang
,
Jin Miyawaki
,
Masaharu Tsuji
,
Isao Mochida
,
Seong-Ho Yoon
,
康飞宇
新型炭材料
doi:10.1016/S1872-5805(09)60018-4
制备一种炭纳米纤维-天然石墨复合材料,以改善作为锂离子电池阳极材料的天然石墨的倍率性能.通过优化控制天然石墨上炭纳米纤维的生长量及其形状提高了天然石墨的循环性能和倍率性能.与天然石墨原料相比,炭纳米纤维-天然石墨复合材料第一次放电容量达到了95%.炭纳米纤维的生长量被严格地控制在天然石墨质量的15%以下.研究发现:由于炭纳米纤维对充放电过程中阳极的体积膨胀和收缩程度的控制作用,天然石墨表面边位上生长的类似常青藤形的炭纳米纤维对倍率性能的提高最为有效.提出采用炭纳米纤维-天然石墨复合材料的原理结构模型解释重复充放电过程中电极的体积稳定性.通过在石墨表面上生长类常青藤形炭纳米纤维而使得SEI(固体电解质界面)变薄并减少了充放电过程中阳极的体积变化,因而提高了倍率性能.
关键词:
天然石墨
,
锂离子电池
,
炭纳米纤维
,
倍率性能
,
体积稳定性
Jiyoung Kim
,
Dong-Hyun Peck
,
Byungrok Lee
,
Seong-Ho Yoon
,
Doo-Hwan Jung
新型炭材料
doi:10.1016/S1872-5805(16)60020-3
采用活性炭纤维为原料制备出膜/电容脱盐系统,提纯含氯化钠的水。 OG系列活性炭纤维作为电极的活性材料,其比表面积和孔分布不同而呈现不同的活化程度。将这些材料用于膜/电容脱盐系统,评价了他们对钠离子或氯离子的脱盐性能。膜/电容实验在不同操作电位窗口、含盐溶液的进料速率和浓度下进行。 OG系列活性炭纤维对每种离子的脱盐效率和电吸附量来评价膜/电容性能。结果表明,BET比表面积是确保高性能的必要因素。另外,炭材料最上端的浅孔有助于活性炭纤维比表面积的充分利用。 OG7A样品的孔结构适合于钠离子吸附,OG10A和 OG15A适于大量孔吸附氯离子。因此,非对称电极排列施加于吸附离子的尺寸,应考虑炭材料比表面积和孔面积的有效利用,以得到高性能的膜/电容脱盐系统。
关键词:
电容去离子化
,
活性炭纤维
,
孔尺寸
,
氯离子和钠离子
,
非对称电极
Journal of Alloys and Compounds
The phase diagram of the Ho-Ni binary system was investigated by X-ray diffraction, differential thermal analysis, optical microscopy and electron probe microanalysis techniques. The existence of eight intermediate phases has been confirmed: Ho3Ni, Ho3Ni2, HoNi, HoNi2, HoNi3, HO2Ni7, HoNi5, and Ho2Ni17. The homogeneity region of the HoNi2 phase extends from 65.6 to 66.7 at.% Ni. The other phases are line compounds. No appreciable solid solubility of holmium in nickel or of nickel in holmium was observed. Ho3Ni2 exists in two structural modifications depending on the temperature. HoNi and HoNi5 melt congruently at 1060 and 1370-degrees-C respectively. There are seven peritectic reactions and three eutectic reactions in this system.
关键词:
intermetallic compounds
王燕
,
常勇
,
殷绍唐
,
王晓光
,
曹余惠
人工晶体学报
doi:10.3969/j.issn.1000-985X.2002.04.014
本文采用Boltzmann分布近似,计算了不同温度下Tm→Ho的净能量转移;计算了实验中不同温度下Ho3+离子的荧光发射强度在整个Tm-Ho体系荧光发射中的比例.我们的实验和计算表明,对Tm-Ho准三能级体系采用Boltzmann分布近似,其计算结果是可信的.
关键词:
Cr,Tm,Ho∶YAG晶体
,
Boltzmann分布近似
,
能量转移效率
Materials Letters
The effect of various holmium content on the microstructure and compressive behavior of NiAl-28Cr-6Mo-0.15Hf eutectic alloy has been investigated by using combination of SEM, TEM and compression test. The results suggest that appropriate Ho addition improves the compressive ductility at room temperature and the high temperature strength at 1273 K of the alloy significantly. In addition, lamellar microstructure inside of eutectic cell and eutectic cell get refinement gradually, but the intercellular region become coarse, with increase of Ho content. Furthermore, Ni2Al3Ho phase, with hexagonal cristal structure, is observed in the alloy. (C) 2008 Elsevier B.V. All rights reserved.
关键词:
NiAl-based alloy;microstructure;mechanical properties;mechanical-properties;composites;toughness;cr
赵业权
,
徐悟生
,
徐衍岭
,
杨春晖
,
徐玉恒
人工晶体学报
doi:10.3969/j.issn.1000-985X.1998.01.011
在生长LiNbO3晶体过程中掺进ZnO和Ho2O3,生长出Zn:Ho:LiNbO3晶体.测试了Zn:Ho:LiNbO3晶体的双折射梯度、光损伤阈值、吸收光谱和荧光光谱.研究表明,Zn:Ho:LiNbO3晶体是优良的激光介质材料.
关键词:
Zn:Ho:LiNbO3晶体
,
光损伤阈值
,
荧光光谱
,
吸收光谱
,
引上法晶体生长
,
激光晶体
Journal of Alloys and Compounds
We have studied the magnetic properties of Ho2Co17-xGax compounds (x less than or equal to 7) by means of magnetic measurements and X-ray diffraction on magnetically aligned powders. The Curie temperature and the spontaneous moment decrease strongly with increasing Ga concentration. The compounds that are magnetically ordered at roam temperature have an easy magnetisation direction at room temperature which is perpendicular to the c-direction. (C) 1998 Elsevier Science S.A.
关键词:
rare earth compounds;Co rich compounds;magnetic properties
成诗恕
,
程艳
,
赵呈春
,
李东振
,
徐晓东
,
徐军
人工晶体学报
采用中频感应提拉法成功生长出Yb (15 at%),Ho (1 at%):YAG激光晶体,研究了室温下晶体的吸收光谱,发射光谱特性和荧光寿命.吸收光谱中在938 nm处存在Yb3+的吸收带,能与InGaAs 激光二极管(LD)有效耦合,适合激光管二极抽运.荧光光谱中存在两个荧光主峰,分别位于1907 nm和2091 nm附近.研究表明:Yb,Ho:YAG晶体是一种有发展前景的激光增益介质.
关键词:
Yb,Ho:YAG晶体
,
提拉法
,
晶体生长
,
光谱特性
Applied Physics Letters
The compound Ho(2)In exhibits two successive magnetic phase transitions: a spin-reorientation transition at T(SR)=32 K and a magnetic-ordering transition at T(C)=85 K. The maximum reversible -Delta S(M) values are 6.3 and 11.2 J/kg K at T(SR) and T(C), respectively, for a field change of 5 T. These two -Delta S(M) peaks with the same sign are partly overlapping, which results in a wide temperature interval with appreciable magnetocaloric effect. The results on Ho(2)In indicate that materials with successive SR and magnetic-ordering transitions may constitute an important new class of magnetic refrigerants since they work in a wider temperature range than the conventional refrigerant materials.
关键词:
holmium alloys;indium alloys;magnetic cooling;magnetic moments;magnetic transitions;magnetic refrigeration;diffraction;capacity;heat
Journal of Applied Physics
A series of orthorhombic manganites Gd(1-x)Ho(x)MnO(3) (0 <= x <= 0.5) are synthesized. The Ho doping leads to a transition of paraelectric phase into ferroelectric one, making Gd(1-x)Ho(x)MnO(3) multiferroic. It is argued that the enhanced electric polarization originates from the transition of the A-type Mn(3+) anti-ferromagnetic state into the spiral spin order driven by the reduction of Mn-O-Mn bond angle due to the doping. The noncollinear spin order of the A-site Ho(3+) spins at high doping level may also make contribution to the polarization. (c) 2011 American Institute of Physics. [doi: 10.1063/1.3535543]
关键词:
polarization;perovskite
