A brannerite type cobalt vanadate conversion anode for lithium batteries

The vanadium-based oxide compounds involved in the conversion reaction deserve the most attention in fabricating anode material for lithium batteries. This work is concentrated on the electrochemically driven conversion reaction mechanism behind the brannerite type CoV₂O₆ anode material synthesized by hydrothermal method. It exhibits an initial irreversible capacity of 939 mAh g^?1; however, a 40 % capacity fading has been observed in the second cycle with retention of 80 % up to the 30th cycle. The reversible discharge capacity in the second cycle is still more than the theoretical capacity of cobalt vanadate. The conversion reaction of CoO nano-particles into Co quantum dots resided in amorphous lithiated vanadium oxide matrix acted as a reactive site as well as the separator to preserve the nano-particles from further agglomeration, then better rate capability. The brannerite type conversion electrode material with such features may give light on the search of a new anode for Li batteries.     

Synthesis and Crystal Structure of 2-[（2-Chloropyridin-4-yl）oxy]-3,3-diphenyl-3-methoxypropionic Acid

The title compound was synthesized and its crystal structure was determined by single-crystal X-ray diffraction.The crystal is of orthorhombic system(C21H18ClNO4,Mr = 383.81),space group Pca21 with a = 13.913(3),b = 10.273(2),c = 26.488(5),V = 3786.1(13) 3,Z = 8,Dc = 1.347 g/cm3,F(000) = 1600,μ = 0.228 mm-1,the final R = 0.0550 and wR = 0.1278 for 5065 observed reflections(I > 2σ(I)).The title compound in a racemic form was found to exist as a mixture of two enantiomers in an equal ratio in the unit cell.The intermolecular hydrogen bonds link the molecules in a head-to-end manner to generate an infinite chain.     

Electric and magnetic dipole couplings in split ring resonator metamaterials

In this paper, the electric and the magnetic dipole couplings between the outer and the inner rings of a single split ring resonator (SRR) are investigated. We numerically demonstrate that the magnetic resonance frequency can be substantially modified by changing the couplings of the electric and magnetic dipoles, and give a theoretical expression of the magnetic resonance frequency. The results in this work are expected to be conducive to a deeper understanding of the SRR and other similar metamaterials, and provide new guidance for complex metamaterials design with a tailored electromagnetic response.     

Sr2CeO4电荷迁移发光的光谱结构规律研究

利用高温固相反应法分别合成了不同物相形成机理的Sr₂CeO₄，Sr ₂CeO₄∶Ca ²⁺和Sr₂CeO₄∶Ba²⁺样品，并对其光谱特性进行 了研究.结果发现，对于由SrO和CeO₂直接反应生成的Sr₂CeO₄(Ⅰ)，激发主峰位于256nm 左右；而对于SrCeO₃和SrO反应生成的Sr₂CeO₄(Ⅱ)，激发主峰位于279nm左右.在Sr₂CeO₄(Ⅰ)中掺入Ca²⁺，其激发光谱随着Ca²⁺离子浓度的增加逐渐接近于Sr₂CeO_{4(Ⅱ)的激发光谱.激发主峰带应属于CeO6八面体终端Ce⁴⁺—O^2-键的电荷迁移 带.对于激发光谱中340nm左右的弱激发峰，其峰值波长不受形成机理及Ca²⁺掺杂的影响，只是其强度 随着 激发主峰的红移而增加，它可能属于CeO6八面体平面上Ce⁴⁺—O2-键的电荷 迁移带.形成机理及Ca²⁺掺杂对发射光谱没有影响.Ca²⁺在Sr 2CeO 4(Ⅱ)与Ba²⁺在Sr2CeO4(Ⅰ)和(Ⅱ)中均难 于替代Sr²⁺的位置.}     

Design, synthesis and biological activity of cyclohexane-bearing C-glucoside derivatives as SGLT2 inhibitors

Seven cyclohexane-bearing C-glucoside derivatives (7, 9, 12, 13 and 17-19) were designed and synthesized as SGLT2 inhibitors starting from a potent SGLT2 inhibitor we discovered in earlier work, (1S)-1-deoxy-1-[4-methoxy-3-(trans-n-propylcyclohexyl)methylphenyl]-D-glucose (1). The in vitro and in vivo biological activities were evaluated by hSGLT2/hSGLT1 inhibition and urinary glucose excretion (UGE), respectively. Among the synthesized compounds 12, the 6-deoxy derivative of 1 was the most active and selective SGLT2 inhibitor (IC50 = 1.4 nmol/L against hSGLT2; selectivity = 1576). Compound 12 was a potent SGLT2 inhibitor, which could induce more urinary glucose than 1 and dapagliflozin in UGE.     

北京谱仪μ子计数器离线数据刻度研究

介绍了北京谱仪(BES)μ子计数器的结构,分析了μ子计数器z向位置分辨变坏的主要因素,通过研究μ子计数器离线数据刻度基本原理和刻度方法,采用新的刻度方法解决了μ子计数器z向位置分辨变坏的问题,使μ子计数器z向位置分辨提高了20%.     

Structural response of polyelectrolyte dendrimer towards molecular protonation: the inconsistency revealed by SANS and NMR

Polyamidoamine (PAMAM) dendrimers and their charged state in deuterium oxide have been investigated with proton pulsed field gradient diffusion nuclear magnetic resonance (PFG-NMR) and small-angle neutron scattering (SANS) techniques. NMR measurements suggest that significant variation of the hydrodynamic radius, calculated by the Stokes-Einstein relation with appropriate surface conditions, is observed upon increasing the molecular protonation. However, a comparative SANS experiment indicates little dependence of the dendrimer global size, in terms of its radius of gyration, on molecular protonation. The inconsistency indicates the necessity of incorporating the effect of molecular interface modification and molecular porosity provided by dressed counterions, when dynamical measurements are used for the determination of the structural characteristics of ionic soft colloids even in dilute suspensions.     

微波辐射法制备Cu-SSZ-13催化剂及其对柴油车尾气NOx的脱除

采用微波辐射法和传统水热法分别制备了Cu-SSZ-13催化剂,用于柴油车尾气NO_x的脱除.用X射线衍射(XRD)、N₂物理吸脱附、H₂程序升温还原(H₂-TPR)、电子顺磁共振(EPR)、NH₃程序升温脱附(NH₃-TPD)、电感耦合等离子体质谱(ICP-MS)及X射线光电子能谱(XPS)等方法对样品进行表征.结果表明,微波辐射法大大缩短了SSZ-13分子筛的晶化时间,晶化9 h制得样品的结晶度与传统水热法晶化72 h制得样品的结晶度相近,同时孔结构参数也得到了一定程度的改善,微波辐射法制备样品的Brönsted(B)酸性位和Lewis(L)酸性位增多,活性组分铜的负载量也得到显著的提高,使得微波辐射法制备的催化剂呈现出优异的低温活性和水热稳定性.     

白光LED用荧光粉Ba_(1.97)Ca_(1-x)(B_3O_6)_2∶Eu_(0.03)~(2+),Mn_x~(2+)的制备及其发光特性

采用高温固相反应法制备了Ba1.97Ca1-x(B3O6)2∶Eu2+,Mnx2+(x=0,0.03,0.06,0.15)荧光粉,研究了其相组成与荧光特性。结果表明,样品具有单相Ba2Ca(B3O6)2晶体结构。Eu2+同时占据Ba2+格位和Ca2+格位。在317 nm波长的紫外光激发下,Eu2+辐射出峰值在450 nm附近的宽谱蓝光。通过能量传递作用,Mn2+辐射峰值为600 nm左右的宽谱红光。蓝光和红光叠加形成色坐标为(x=0.371,y=0.282)的近白光发射。样品的激发光谱分布在250~400 nm的波长范围,有望在紫外激发的白光LED中获得应用。