TiO2 coating of LiNi1/3Co1/3Mn1/3O2 cathode materials for Li-ion batteries

TiO₂-coated LiNi_1/3Co_1/3Mn_1/3O₂ materials were prepared by the hydrolyzation of Ti(OBu)₄. The impact of TiO₂ coating on the structure and electrochemical properties of LiNi_1/3Co_1/3Mn_1/3O₂ was investigated using X-ray diffraction, scanning electron microscope, and charge–discharge tests. The results indicated that TiO₂ coating did not affect the lattice of LiNi_1/3Co_1/3Mn_1/3O₂, but exhibited obvious effects on its discharge capacity and cycling stability. As coated TiO₂ increased from 0.0 to 2.0 mol%, the initial capacity of samples decreased slightly, but the cycling stability over 2.5∼4.3 V increased remarkably. The capacity retention reached 99.5% at the 50th cycle at a coating amount of 2.0 mol%.     

Synthesis of PAN/SnCl2 composite as Li-ion battery anode material

A novel process was proposed to synthesize the pyrolytic polyacrylonitrile (PAN)/SnCl₂ composite anode material for Li-ion batteries. The preparation started with the dissolution of PAN and SnCl₂ in dimethylformamide (DMF), followed by drying of the solution and pyrolysis of the dried mixture of PAN and SnCl₂ at 300 °C, leading to homogenous dispersal of SnCl₂ in pyrolytic PAN, which becomes conducting polymer matrix. The composite presented stable cycling capacity of about 490 mAh/g. It is demonstrated that SnCl₂, which has been considered to be an inactive electrode material, can become active by the proposed composite technique. This paves the promising way to prepare electrode materials for Li-ion batteries.     

Influences on power performances of metal oxide additives for LiFePO4 electrodes

Metal oxide additives are added into LiFePO₄ electrodes attempting to improve cell power performances. Electrochemical performances are tested with 5 wt% different sizes of neutral alumina, nano Al₂O₃, and nano MgO individually comparing with those with 5 wt% more active LiFePO₄ and acetylene black. The polarization between charge and discharge plateaus is reduced not only by adding more conductive acetylene black, but also by adding all these insulated metal oxide additives. Adding natural alumina and nano MgO can significantly increase rate capacities. This might be because of their “lithium ion saver” effect.     

Synthesis of glycosyl disulfides containing an α-glycosidic linkage

A wide range of symmetrical and unsymmetrical glycosyl disulfides is synthesized with focus on the use of α-glycosyl thiols. Oxidation of α-glycosyl thiols with iodine leads to symmetrical α,α-glycosyl disulfides, while unsymmetrical disulfides are readily synthesized from α- and β-glycosyl thiols under the action of DDQ. Thus, glycosyl disulfides containing at least one α-glycosidic linkage are made available.     

New Principles for Glycoside‐Bond Formation

Meeting the demand for sugars : The importance of oligosaccharides and glycoconjugates in biological systems has stimulated a need to access significant amounts of these compounds. Much effort has been devoted to the stereoselective generation of the key glycosidic bond, both between carbohydrate residues (see scheme) and to the aglycone. Various methodologies are now available for the efficient synthesis of structurally defined complex oligosaccharides and glycoconjugates.

     

硝基苯气相加氢催化剂Cu／SiO2的改性研究

硝基苯气相加氢催化剂Ｃｕ／ＳｉＯ２的改性研究方向明＊李凤仪夏克坚秦中（南昌大学现代应用化学研究所南昌３３００４７）（江西ＯＡＩ－中德联合研究院南昌）关键词硝基苯，苯胺，加氢催化剂１９９６－０８－０２收稿，１９９６－１１－１８修回苯胺是染料、医药、农药...     

玻璃基板作用下高分子共混物薄膜相形态发展过程

研究了玻璃基板作用下极性高聚物为低组分的共混物薄膜在退火条件下相形态的发展过程 .选用聚苯乙烯 (PS) 聚甲基丙烯酸甲酯 (PMMA)与聚苯乙烯 (PS) 聚ε 己内酯 (PCL)两个体系 ,在玻璃基板上Spin Coating成膜后退火 .由于共混物薄膜中极性相对较大的高聚物组分 (PMMA和PCL)相对于极性较小的PS组分对玻璃基板具有更好的润湿性 ,所以在上述的两个共混薄膜体系中其相形态分别显示PMMA和PCL在低组分比例下最终发展成为连续相 .利用扫描电镜以及元素分析很好地验证了以上的结论 ,并且对其机理进行了解释 .此外 ,改变PS的分子量与PCL共混 ,研究了组分粘度对薄膜相形态发展的影响 .结果表明 ,PS组分粘度越大 ,共混物薄膜相结构发展速度越慢     

固定型阀控式铅酸蓄电池失效模式研究

研究了由于水损耗、热失控而引起固定型阀控式铅酸蓄电池失效的原因．认为通过提高电池内部氧再复合效率、采用合适的电池槽盖材料及减少正极板腐蚀,可解决水损耗问题;热失控问题可通过改善电池外部条件解决．     

Determination of Internucleotide JHN Couplings by the Modified 2D JNN-Correlated [N, H] TROSY

Recent developments in the direct observation of J couplings across hydrogen bonds in proteins and nucleic acids provide additional information for structure and function studies of these molecules by NMR spectroscopy. A J_NN-correlated [¹⁵N, ¹H] TROSY experiment proposed by Pervushin et al. (Proc. Natl. Acad. Sci. USA 95, 14147–14151, 1998) can be applied to measure ^hJ_HN in smaller nucleic acids in an E.COSY manner. However, it cannot be effectively applied to large nucleic acids, such as tRNA^Trp, since one of the peaks corresponding to a fast relaxing component will be too weak to be observed in the spectra of large molecules. In this Communication, we proposed a modified J_NN-correlated [¹⁵N, ¹H] TROSY experiment which enables direct measurement of ^hJ_HN in large nucleic acids.     

防伪技术的新突破——核径迹防伪技术

用核粒子照射塑料薄膜形成径迹,再经化学试剂蚀刻和成像技术,得到由微米级微孔组成的图案。这种图案具有物质特性。用这种方法生产的核径迹防伪标志,具备核尖端技术不易扩散,制作设备不易得到,产品用其他方法难以伪造,防伪识别简单、快速、可靠等特点,此种标志已经通过放射性安全检测,可以用于各种商品（包括食品）的包装。