锂离子电池硅基复合物负极材料*

作为颇有前途的锂离子电池负极材料,硅基材料的研究日益受到重视。硅基负极材料在充放电循环中体积变化过大导致的循环性能差、首次库仑效率低等始终是阻碍其商业化的主要问题。纳米化、合金化和碳包覆是有效的解决措施。本文详细论述了TiB2、TiN、TiC作为基质的硅-化合物复合物,Fe-Si、Cu-Si、Ni-Si体系的硅-金属复合物和硅-碳复合物的研究进展。在硅-碳复合物的研究上,综述了分别采用热解法、球磨法、球磨-热解法、化学聚合法合成,以聚吡咯、聚氯乙烯、聚丙烯腈、间苯二酚-甲醛、柠檬酸、环氧树脂等为碳源的研究进展,同时也综述了Si/碳纳米管复合电极材料的研究情况。     

Dynamic behavior of bridge-erecting machine subjected to moving mass suspended by wire ropes

The dynamic behavior of a bridge-erecting machine, carrying a moving mass suspended by a wire rope, is investigated. The bridge-erecting machine is modelled by a simply supported uniform beam, and a massless equivalent “spring-damper” system with an effective spring constant and an effective damping coefficient is used to model the moving mass suspended by the wire rope. The suddenly applied load is represented by a unitary Dirac Delta function. With the expansion method, a simple closed-form solution for the equation of motion with the replaced spring-damper-mass system is formulated. The characters of the rope are included in the derivation of the differential equation of motion for the system. The numerical examples show that the effects of the damping coefficient and the spring constant of the rope on the deflection have significant variations with the loading frequency. The effects of the damping coefficient and the spring constant under different beam lengths are also examined. The obtained results validate the presented approach, and provide significant references in the design process of bridgeerecting machines.     

乙酰胺-尿素-NaBr熔体中Eu-Co合金的电化学制备

利用循环伏安法,研究证明在80℃的乙酰胺-尿素-NaBr熔体中,Co（Ⅱ）还原为金属Co是不可逆过程,Eu（Ⅲ）不能单独还原为Eu,但可以被Co（Ⅱ）诱导而共沉积。由恒电位电解法得到非晶态的Eu-Co合金,Eu的含量随阴极电位的负移,Eu（Ⅲ）/Co（Ⅱ）摩尔比增大及电解时间延长而增大。     

{Bis[N,N′-(2-alkyl-6-para-methylphenyl)phenyl)imino]acenaphthene}dibromonickel catalysts bearing bulky methylphenyl groups: synthesis,characterization, crystal structures and application in catalytic polymerization of ethylene and styrene

Two new Ni(II) complexes containing methylphenyl groups, {bis[N,N′-(2,6-dimethyl-4-p-methylphenylphenyl)imino]acenaphthene}dibromonickel 4a and {bis[N,N′-(2-ethyl-4,6-di(p-methylphenyl)phenyl)imino]acenaphthene}dibromonickel 4b, were synthesized and characterized. The molecular structures of both complexes were determined by single-crystal X-ray diffraction. Both complexes have pseudo-tetrahedral geometry about the nickel center, showing pseudo C _2v and C ₂ molecular symmetry, respectively. Complex 4c, {bis[N,N′-(2,4,6-trimethylphenyl)imino]acenaphthene}dibromonickel, was also synthesized for comparison. These complexes were tested as catalysts for the polymerization of ethylene and styrene under mild conditions using diethylaluminum chloride. The precatalyst 4b bearing one ortho-ethyl group and two bulky p-methylphenyl groups in the ortho- and para-aryl position of the ligand, displayed highly catalytic activity for the polymerization of ethylene [4.70 × 10⁶ g PE/(mol Ni h bar)], and produced branched polyethylene (76 methyl, 8 ethyl, 5 propyl and 22 butyl or longer branches/1,000 C at 60 °C). Interestingly, complex 4b also displays high catalytic activity [5.46 × 10⁵ g polystyrene/(mol Ni·h)] for styrene polymerization and produces nearly atactic polystyrene at 70 °C (stereo-triad distributions: rr, 39.9 %; mr, 30.4 %; mm, 29.8 %; stereo-diad distributions: r, 55.1 %; m, 44.9 %).     

三齿多吡啶钴(Ⅱ)配合物的合成、表征及其与DNA的相互作用研究

合成了两种三齿多吡啶钴(Ⅱ)配合物[Co(DMPhTPY)2]2+(ClO-4)2(A)和[Co(H2Bzimpy)2]Cl2(B),用元素分析、IR对配合物的组成和结构进行了表征,测定了配合物A的晶体结构.用电子吸收光谱、荧光光谱、循环伏安法及凝胶电泳实验等方法研究了配合物与DNA的相互作用.结果表明配合物A和B与小牛胸腺(CTDNA)的作用属部分插入和静电结合,凝胶电泳实验表明配合物A在310nm光辐射15min,可使超螺旋pBR322DNA断裂为开环缺口型和线型DNA.     

不同形貌氧化锰纳米材料的研究进展

不同形貌氧化锰纳米材料由于具有离子筛、分子筛、催化和电化学等许多特殊的物理和化学性质,因而在吸附材料、催化材料、锂离子二次电池的正极材料和新型磁性材料等领域显示了广阔的应用前景。本文综述了不同形貌氧化锰纳米材料几种常用的制备方法,包括溶胶-凝胶法、汽-液-固(VLS)生长法、回流法等,并对各种方法的特点作了总结。最后,讨论了不同形貌氧化锰纳米材料的应用及研究展望。     

Cu_(30)Cr_5/碱性氧化铝催化2,2,6,6-四甲基哌啶酮加氢(英文)

在2,2,6,6-四甲基哌啶酮连续化加氢生成2,2,6,6-四甲基哌啶醇的反应中,Cu30Cr5/碱性氧化铝比Cu30Cr5/γ-Al2O3具有更优异的催化性能,反应的转化率和选择性分别高达99.0%和97.2%.N2物理吸附-脱附、X射线光电子能谱、X射线衍射和氨气程序升温脱附结果表明,Cu0作为催化加氢反应的活性中心,在Cu30Cr5/碱性氧化铝中具有更好的分散性,且随着碱性氧化铝的引入,催化剂酸性大幅下降,从而有效抑制副产物2,6-二甲基-4-庚酮的生成,因而产物2,2,6,6-四甲基哌啶醇的选择性显著提高.     

Synthesis and structure elucidation of five new pyrimido[5,4-c]quinoline-4(3H)-one derivatives using 1D and 2D NMR spectroscopy

Five new 2-(amino/aroxy)-5-methylpyrimido[5,4-c]quinolin-4(3H)-one derivatives have been designed and synthesized via an aza-Wittig reaction, and the structure elucidation was accomplished using extensive 1D ((1)H, (13)C) and 2D NMR spectroscopic studies (COSY, HSQC and HMBC experiments).     

6-烷氨(氧)基-3-甲硫基-1H-吡唑并[3,4-d]嘧啶-4(5H)-酮衍生物的合成与生物活性

用六氯乙烷、三苯基膦和5-氨基吡唑衍生物一锅法合成关键中间体膦亚胺。 再利用串联aza-Wittig反应,加入对氯苯基异氰酸酯,进一步和烷基胺或取代酚反应合成了11个未见文献报道的6-烷氨（氧）基-3-甲硫基1H-吡唑并[3,4-d]嘧啶-4(5H)-酮衍生物。 通过1H NMR、EI-MS、IR和元素分析等方法对所合成的化合物进行了结构表征,并测试了它们的杀菌和除草活性。 测试结果表明,部分化合物对稗草(barnyard grass)和油菜(Rape)均表现出了较好的抑制活性。     

Novel near-infrared fluorescent liquid crystal: Bodipy bearing multiple alkyl chains with columnar mesophase

By the typical Knoevenagel condensation of Bodipy with aldehyde derivatives, two novel Bodipy derivatives 3 and 6 with symmetric three and six alkyl chains were designed and prepared. The Bodipy derivative 3 with three alkyl chains showed no mesophase but the Bodipy derivative 6 with six alkyl chains possessed the orderly hexagonal columnar mesophase at room temperature. Both samples 3 and 6 exhibited the near-infrared fluorescence with high fluorescence quantum yields and larger Stokes shifts than their Bodipy precursors. Sample 6 was the first near-infrared fluorescent columnar liquid crystal with Bodipy core. This research presented a good strategy on constructing the near-infrared columnar Bodipy liquid crystal.