Revealing the conversion mechanism of CuO nanowires during lithiation-delithiation by in situ transmission electron microscopy

Being promising candidates for anodes in lithium-ion batteries (LIBs), transition metal oxide anodes utilizing the so-called conversion mechanism principle typically suffer from the severe capacity fading during the 1st cycle of lithiation-delithiation. Herein, we directly investigated these processes using an individual CuO nanowire anode and constructed a lithium ion battery (LIB) prototype within a transmission electron microscope.     

CoO octahedral nanocages for high-performance lithium ion batteries

Pure-phase CoO octahedral nanocages were successfully fabricated by a novel simple method. The coordination etching agents play key roles in the formation of these non-spherical hollow structures. When tested as anode materials in lithium ion batteries (LIBs), these nanocages showed excellent cycling performance, good rate capability and enhanced lithium storage capacity.     

Erosion Profile by a Global Model for Granular Flow

In this paper we study an integro-differential equation that models the erosion of a mountain profile caused by small avalanches. The equation is in conservative form, with a non-local flux involving an integral of the mountain slope. Under suitable assumptions on the erosion rate, the mountain profile develops several types of singularities, which we call kinks, shocks and hyper-kinks. We study the formation of these singularities and derive admissibility conditions. Furthermore, entropy weak solutions to the Cauchy problem are constructed globally in time, taking limits of piecewise affine approximate solutions. Entropy and entropy flux functions are introduced, and a Lax entropy condition is established for the weak solutions.     

准晶数学弹性理论和某些有关研究的进展(上)

本文对固体准晶力学性能和准晶数学弹性, 塑性, 断裂以及有关研究的进展作了评论, 尤其对材料常数和塑性变形行为的测量, 一维、二维、三维准晶弹性理论, 动力学、非线性、缺陷理论、准晶弹性新型偏微分方程的推导和精确分析解, 复分析方法, 变分原理和有限元方法, 有限差分方法这些宏观问题和它们的数学方法进行了分析, 同时对准晶晶格动力学问题的数学理论也作了初步讨论. 近来在软物质中发现了12 次和18次对称准晶, 意义重大, 这里也做了初步介绍. 文中重点讨论此领域最近这些年来中国科学工作者的工作.      

Solutions for hydrodynamics of 5- and 10-fold symmetry quasicrystals

This study carries out a complete analysis of time-space solution of hydrodynamics of pentagonal/decagonal quasicrystals. The behaviors of wave propagation for phonons and diffusion for phasons and coupling between phonon-phason fields are explored explicitly. Comprehensive discussion on physical time-space variations of all hydrodynamic field variables of the alloy quasicrystals is given. The computational specimen is simple, convenient in testing computational results, and provides a possibility that is easy to test experimentally. The quantitative results of mass density, viscosity velocities, phonon displacements, phason displacements, phonon stresses, phason stresses, viscosity stresses, and their time-space variations help us understand the motion of solid quasicrystals in a hydrodynamic condition (long-wavelength and low-frequency). The analysis presented in this paper can be used for octagonal and dodecagonal quasicrystals and is easily extended to other two-dimensional quasicrystals and three-dimensional icosahedral quasicrystals. Some problems explored by the computational results are also discussed.     

PPV中极化子动力学方程的龙格-库塔求解

构造求解-阶微分方程组初值问题的八阶龙格-库塔递推公式,结合描述有机分子运动的-维紧束缚模型,研究PPV原子链中极化子的形成及运动.对碳原子数N=160的PPV原子链,由可控步长八阶龙格-库塔公式求解2N(2N+1)=102720个方程组成的方程组,用Fortran语言编程计算,得到稳定的极化子结构和运动图像;在场强E=1×105V·cm^-1的电场作用下,极化子沿分子链的运动速率约为0.2635Å·fs^-1.计算结果表明,八阶龙格-库塔方程可以有效地用于有机分子链中载流子运动的模拟.     

沸石分子筛的生成机理与晶体生长(Ⅻ)——ZSM-5沸石生成过程中液相硅酸根离子聚合态的研究

自从1964年Lentz等人提出三甲基硅烷化(TMS)方法研究硅酸盐结构后,人们意识到这种方法能够较真按着地反映硅酸盐结构及聚合状态。又由于硅烷化所得的衍生物(硅酯)易溶于有机溶剂,可以采用多种方法进行分析鉴定。本文应用TMS-GLC及TMSGPC二种方法研究了ZSM-5沸石生成过程中液相硅酸根离子聚合状态的变化。     

Preparation and properties of thermo-sensitive organic/inorganic hybrid microgels

By utilizing the hydrolysis and condensation of the methoxysilyl groups, thermo-sensitive organic/inorganic hybrid poly[ N-isopropylacrylamide- co-3-(trimethoxysilyl)propylmethacrylate] [P(NIPAm- co-TMSPMA)] microgels were successfully prepared via two different methods without addition of any surfactant. First, the microgels were obtained by a two-step method; that is, the linear copolymer P(NIPAm- co-TMSPMA) was first synthesized by free radical copolymerization, and the aqueous solution of the copolymer was then heated above its low critical solution temperature (LCST) to give colloid particles, which were subsequently cross-linked via the hydrolysis and condensation of the methoxysilyl groups to form the microgels. Second, the microgels were also prepared via conventional surfactant-free emulsion polymerization (SFEP) of the monomers NIPAm and TMSPMA. TMSPMA can act as the cross-linkable monomer. No surfactant was involved in the preparation of the hybrid microgels. The obtained microgels were rather spherical and exhibited reversible thermo-sensitive behavior. The size, morphology, swellability, and phase transition behavior of the microgels were dependent on the initial copolymer or monomer concentration, preparation temperature, and the content of TMSPMA. The size of microgels obtained by SFEP was found to be more uniform than that by the two-step method. The hybrid microgels obtained by these two methods had more homogeneous microstructures than those prepared via conventional emulsion polymerization with chemical cross-linker N, N'-methylene-bisacrylamide.     

循环加载条件下混凝土Ⅰ型裂缝扩展模拟的接触算法

沿裂缝可能开展路径设置接触点对,把求解接触问题的有限元混合法进行扩展,以实现循环加载条件下混凝土Ⅰ型裂缝扩展的数值模拟.根据荷载过程状态和缝面接触状态的不同,将循环荷载作用下的混凝土本构关系抽象为力学模型中的六种不同接触状态,不同的接触状态对应着不同的位移-应力曲线关系.以缝面张开位移和接触应力作为接触状态转变的判断参量,并给出了各状态的转变关系和数值判断条件,以接触算法实现了循环加载条件下混凝土Ⅰ型断裂扩展的数值模拟.首先给出了有限元混合法求解接触问题的基本思路,然后引入循环荷载下的混凝土本构关系,再对Ⅰ型裂缝扩展的数值实现方法进行了阐述,最后通过数值算例说明了数值实现方法的正确性和有效性.     

A Recyclable and Scalable High-Capacity Organic Battery

Redox organic electrode materials (OEMs) have attracted extensive attention for batteries due to the possibility to be designed with high performance. However, the practical application of OEMs requires rigor criteria such as low cost, recyclability, scalability and high performance etc. and hence seems still far away. Here, we demonstrate an OEM for high performance aqueous organic batteries. Quantification of the charge storage confirmed the storage of protons with fast reaction kinetics, thereby enabling the high performance at high mass loading. As a result, the laminated pouch cells delivered Ampere-hour-scale capacity with excellent cycling performance. Benefited from the small molecular nature and the stable both charged and discharged states, the electrodes can be recycled at any states of charge with high yields (more than 90 %). This work provides a substantial step in the practical applications of OEMs for the future sustainable batteries.