Tin nanoparticles embedded in ordered mesoporous carbon as high-performance anode for sodium-ion batteries

Tin (Sn) has been considered as an attractive anode material for sodium-ion batteries (SIBs) due to its high theoretical capacity (847 mAh g^?1). Nevertheless, its low conductivity and large volume change during cycling essentially prevent the possibility of high capacity and long-term cycle for SIBs. In this work, Sn nanoparticles are well embedded into the highly ordered mesoporous carbon (CMK-3) matrix (Sn@CMK-3) using a facile sonochemical method combined with heat treatment. The resultant Sn@CMK-3 nanohybrid electrode delivers an initial charge capacity of 412 mAh g^?1 at 100 mA g^?1. A reversible capacity of 337 mAh g^?1 is obtained after 200 cycles, indicating the good cycle stability of the nanohybrid structure. The electrode also shows a potential rate capability, which maintains a capacity of 228 mAh g^?1 at 1000 mA g^?1. When the current density returns to 50 mA g^?1, the capacity goes back to 381 mAh g^?1, with a capacity retention of 86.9%. The enhanced sodium storage performance of Sn@CMK-3 nanohybrid can be related to the synergistic effect between CMK-3 and Sn.

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Graphical abstract Sn@CMK-3 nanohybrid with Sn nanoparticles uniformly distributed into the highly ordered mesoporous carbon matrix exhibited good cycling performance and rate capability.

     

Off-on-off luminescent switching of a dye containing imidazo[4,5-f][1,10]phenanthroline

A new acid-base fluorescent switch containing both imidazo[4,5-f][1,10]-phenanthroline and triphenylamine groups has been synthesized.Its fluorescence emissions and absorptions can be reversibiy changed through protonation/deprotonation of imidazole and amine moiety by controlling the intramolecular charge transfer(ICT) process,leading to off-on-off fluorescent molecular switching.     

铁基超导体Minimum模型中的d波和扩展s波

对比研究了Minimum模型中d-波配对和扩展s-波配对的基本性质.结果表明,超导序参量按类BCS关系随温度变化,重整化参数t对超导有抑制作用,当t足够大时,超导消失,系统进入正常金属相.此外,讨论了超导序参量随不同参量的变化关系.对于d波,系统有稳定态;而对于扩展s波,系统则没有稳定态.     

Isomorphism of extensions of C(T~2)

In this paper we give a certain classification theorem of extensions of the torus algebra up to isomorphism and also show that the K 0 -group K 0 (E) and the semigroup V (E) are two complete invariants of such extension algebras.     

Electrochemical properties of rutile TiO2 nanorods as anode material for lithium-ion batteries

In this paper, we synthesized rutile TiO₂ nanorods by hydrolysis of TiCl₄ ethanolic solution in water at 50?°C. Scanning electron microscopy and transmission electron microscopy images show that the as-prepared sample was consisted of nanoflowers of about 500?nm in sizes, and each petal of nanoflowers was assembled by several nanorods. We tested the electrochemical properties of the rutile TiO₂ nanorods as an anode material for lithium-ion batteries. The rutile TiO₂ nanorods exhibited a large initial discharge capacity of 223?mA?h?g^?1, and the stabilized capacity was as high as 170?mA?h?g^?1 after 100 cycles. These improved electrochemical performances may be attributed to the shorter diffusion length for both the electron and Li⁺, and the large electrode?Celectrolyte contact area offered by the nanorods with a large specific surface area, which facilitated the lithium ions insertion and extraction.     

云母1/4波片偏振干涉谱的研究

本文利用岛津UV301－PC分光光计，测定了云母1／4波片的偏振干波谱，该光谱和以往文献中的显著不同。本文对此进行了分析和解释，并由此得出了在考虑吸收的情况下的爱里方程表达形式。该将有助于测定某些晶体的吸光度。     

消色差谱相位延迟器的光谱特性测试研究

本文应用归一化偏振调制原理建立的测试系统，对常规菲涅耳菱体，改进型菲涅菱体，斜入射型以及直角棱镜组合型的消色差相位延迟的光谱特性进行了测试研究，得到了各延迟器的消色差特性曲线，并对测试结果进行了分析。结果表明改进型菲涅耳菱体以及直色棱镜组合型型消色差相位延迟器，是目前较理想的实用型消色相位延迟器。     

关于n阶微分方程边值问题（Ⅲ）——奇摄动的渐近展开

本文研究n阶非线性过值问题(NB)的奇异摄动。在较一般的条件下,应用高阶微分不等式理论证明了摄动解的存在性,并给出了摄动解直到n阶导函数的一致有效渐近展开式,推广和改进了已有的结果。     

带导数项的半正Right Focal边值问题单调正解的存在性

研究下列半正Right F0cal边值问题单调正解的存在性其中λ>0是一个参数,n≥3,1相似文献   

多供应商多零售商下经济批量问题的多项式时间算法研究

基于多供应商和多零售商构成的经济批量问题,通过构建优化模型,分析了订购费用为全部单位数量折扣和增加数量折扣两种情形模型最优解的相关性质。将这些性质应用到动态规划算法设计中,对订购费用为全部单位数量折扣时的一种特殊情形及增加数量折扣的一般情形分别设计了求解问题最优解的多项式时间算法,并用算例说明了算法的执行过程和有效性。