One-pot synthesis of ZnFe2O4/C hollow spheres as superior anode materials for lithium ion batteries

ZnFe(2)O(4)/C hollow spheres have been synthesized via a facile solvothermal route using low cost raw materials. The resulting composite showed a very high specific capacity of 841 mAh g(-1) after 30 cycles and good rate capability.     

Superconvergence of interpolated collocation solutions for Hammerstein equations

In this article, we discuss the superconvergence of the interpolated collocation solutions for Hammerstein equations. Applying this new interpolation postprocessing to the collocation approximation x_h, we get a higher accuracy approximation I x_h, whose convergence order is the same as that of the iterated collocation method. Such an interpolation postprocessing method is much simpler. Also, numerical experiments are shown to demonstrate the efficiency of the interpolation postprocessing method. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2010     

Preparation of alkaline solid polymer electrolyte based on PVA-TiO2-KOH-H2O and its performance in Zn-Ni battery

A novel composite alkaline polymer electrolyte based on poly(vinyl alcohol) (PVA) polymer matrix, titanium dioxide (TiO₂) ceramic fillers, KOH, and H₂O was prepared by a solution casting method. The properties of PVA-TiO₂-KOH alkaline polymer electrolyte films were studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and AC impedance techniques. DSC and XRD results showed that the domain of amorphous region in the PVA polymer matrix augmented when TiO₂ filler was added. The SEM result showed that TiO₂ particles dispersed into the PVA matrix although some TiO₂ aggregates of several micrometers were formed. The alkaline polymer electrolyte showed excellent electrochemical properties. The room temperature (20 °C) ionic conductivity values of typical samples were between 0.102 and 0.171 S cm⁻¹. The Zn-Ni secondary battery with the alkaline polymer electrolyte PVA-TiO₂-KOH had excellent electrochemical property at the low charge-discharge rate.     

拟等级网格下非线性延迟微分方程间断有限元法

本文利用间断有限元法求解非线性延迟微分方程,在拟等级网格下.给出非线性延迟微分方程间断有限元解的整体收敛阶和局部超收敛阶,数值实验验证了理论结果的正确性.     

小卫星二次分离的动力学仿真

采用Adams软件对子星释放过程进行仿真. 在建立分离方案的简化模型、选定合理设计参数的基础上,以1颗子星分离为例,基于Adams平台对分离过程进行仿真,然后基于多体动力学理论对分离过程进行动力学计算,得到了子星的分离速度和角速度. 仿真结果和动力学计算结果是一致的,验证了Adams模型计算的正确性.     

从润湿热研究HZSM-5分子筛与不同液体相互作用的特点

ZSM-5是一类新型分子筛,共物理化学性能的研究引起了广泛的兴趣。本工作测定了高温脱气的HZSM-5分子筛在正己烷、正庚烷,正癸烷、正十二烷,环己烷、苯、甲苯,邻、间、对二甲苯,甲醇和乙醇中的润湿热。     

混煤氮的热解析出特性及燃料NO_x的形成规律

混煤氮的热解析出特性及燃料ＮＯ_ｘ的形成规律邱建荣，马毓义，曾汉才，吕焕尧，喻秋梅（华中理工大学煤燃烧国家重点实验室武汉４３００７４）关键词：混煤，ＮＯ_ｘ，混合比，燃烧。ＥＭＩＳＳＩＯＮＯＦＮＩＴＲＯＧＥＮＣＯＭＰＯＵＮＤＳＡＮＤＮＯ_ｘＦＯＲＭＡＴ?..     

The influence of α-ZrP coat on proton transfer resistance of cation exchange membrane-solution interface

In this work, the effect of surface modification on proton transfer resistance of the membrane and/or membrane surface interface is investigated. Cation exchange membranes, PE01 and Nafion1135, were modified by zirconium phosphate (ZrP) and inorganic-organic composite membranes were prepared. α-ZrP (α-Zr(HPO₄)₂ · H₂O) was deposited on the composite membrane surface as verified by XRD and SEM. Zeta potential of the composite membrane decreases with the increase of immersion time, indicating that the deposition α-ZrP results in a decrease of membrane surface charge density. The proton transfer resistance measured by AC impedance technique in 0.05 mol/L H₂SO₄ solution shows an interesting result: the proton transfer resistance of membrane-solution (Z_e) sharply reduces while proton transfer resistance of membrane (Z_m) increases slightly with the immersion time for both of the membranes. The slight increase of Z_m is due to the deposit of ZrP on membrane surface, and the sharp decrease of Z_e is attributed to the decrease in the static electrical interaction strength between counterions and the charged groups of the membrane, which is caused by interact of α-ZrP with the ion exchange groups resulting in a reduction of membrane surface charge density. The equivalent circuit models for electrode/solution/membrane/solution/electrode system and electrode/solution system were examined. The results observed in this work seem very interesting in the ion transfer study between phase interfaces.     

超高效液相色谱-四极杆-飞行时间质谱定性研究茶叶籽中的酚类化合物

采用超高效液相色谱(UHPLC)-四极杆-飞行时间质谱(Q-TOF/MS)技术定性分析茶叶籽中的酚类化合物。茶叶籽样品经乙醇水溶液提取后经反相色谱分离,通过Q-TOF/MS进行化合物的鉴定。基于山茶属及相关植物化学组成的文献,建立了一个含有106种酚类化合物的数据库。对UHPLC-Q-TOF/MS采集得到的一级质谱数据进行数据库检索,然后对检索到的化合物色谱峰进行二级质谱扫描,根据得到的碎片离子推断化合物的结构。初步推断出茶叶籽提取物中的24种酚类化合物,包括13种酚酸类、4种儿茶素类和7种黄酮类化合物,并通过与标准品比对,进一步确证了这些化合物。结果表明UHPLC-Q-TOF/MS技术可以用于对茶叶籽中酚类化合物进行快速、准确、可靠的定性分析,促进新化合物的发现与鉴别。