Preparation and Characterization of Polymer Microspheres via Vapor-Induced Phase Separation

近年来，嵌段共聚物自组装制备各种类型的聚集体，在纳米反应器、纳米材料、药物缓释和生物组织等方面具有广泛的应用前景。在嵌段共聚物的自组装过程中，总是涉及多种类型的相分离。其中，蒸气诱导相分离(vapor-inducedphaseseparation,VIPS)经常被用来制备多孔薄膜和其它多种聚合物材料。通常，水是作为VIPS过程沉淀剂的首选，然而水与许多有机溶剂都不相溶，从而限制了VIPS的应用。本论文改用可与有机溶剂互溶的甲醇或乙醇作为沉淀剂来研究嵌段共聚物溶液在沉淀剂蒸气诱导下的相分离行为。在溶剂挥发过程中，甲醇或乙醇气体遇冷被聚合物溶液吸收，改变了溶剂的性质，使溶液发生了相分离；同时结合M...Lately, aggregates of block copolymers have attracted extensive attention based on their potential applications as nanoreactors, nanomaterials, drug delivery systems, polymeric tissue scaffolds and so on. Preparation of block copolymer aggregates always involves some types of phase separation technique during the self-assembly process. Among them, the vapor-induced phase separation (VIPS) is widel...学位：理学硕士院系专业：材料学院_高分子化学与物理学号：2072010115010

混凝土受压过程中声发射数的灰色模型研究

针对在混凝土单轴受压破坏全过程的声发射试验中,采用传统GM(1,1)灰色模型多步预测分析所得预测值普遍较实测值偏大、预测精度偏低的问题,通过引进预测值折减系数,重点探讨了折减系数的特点。结果表明,折减系数在预测曲线起点处基本为一常数,在终点处基本与已知数据百分数呈线性关系。基于上述特点通过插值求其折减系数来合理修正传统的灰色模型,建立起折减修正GM(1,1)灰色模型。通过该修正GM(1,1)灰色模型对室内声发射试验建立的预测模型,其精度较传统GM(1,1)灰色模型有较大提高

SBS分子结构对其在选择性溶剂中自组装行为的影响

线形两嵌段(SB)、线形三嵌段[(SB)2]和星形四臂三嵌段[(SB)4]的苯乙烯-丁二烯嵌段共聚物(SBS)溶于选择性溶剂丁酮后的聚集自组装行为差异极大。粘度测定和透射电镜观察结果表明,在溶液中,(SB)4由其内部聚丁二烯嵌段(PBD)聚集自组装成单分子核-壳结构;(SB)2在低于转折浓度时由多个分子的PBD聚集自组装成开放式核-壳结构,在高于转折浓度时则成为稳定聚集体;而SB自组装成为宏观不溶的特大胶体微粒

MnO/Nitrogen-doped graphene composite cathode for high performance lithium oxygen batteries

本文采用水热法制备了MnO/氮掺杂石墨烯复合材料. 作为非水锂空气电池的正极催化剂, 该复合材料表现出了优异的电化学性能以及循环稳定性.; 在充放电电流密度为0.05 mA cm~(-2)时, 其能量效率高达84.6%, 远高于目前文献所报道的非贵金属催化剂的能量效率,; 也超过了基于贵金属的催化剂. 其氧还原反应(ORR)和氧析出反应(OER)的过电势分别仅为0.11和0.41 V.; 扫描电子显微镜(SEM)和透射电子显微镜(TEM)结果表明, 所制备的MnO纳米颗粒能够均匀地分散在氮掺杂石墨烯的表面.; 密度泛函理论(DFT)计算揭示, MnO(100)面是主要的催化活性面, 其理论ORR和OER的过电势分别仅为0.21与0.24 V,; 充放电电势差为0.45 V, 与实验结果0.52 V相当.MnO/nitrogen-doped graphene (MnO/NG) composite cathode was fabricated by; a facile one-pot method as cathode catalyst for non-aqueous lithium; oxygen batteries. It exhibited superior electrochemical performance with; higher round-trip efficiency and better cyclic stability. It showed a; high round-trip efficiency of 84.6% at the current density of 0.05 mA; cm~(-2) with the discharge and charge overpotentials of 0.11 and 0.41 V,; respectively. Through scanning electron microscopy, transmission; electron microscopy and X-ray photoelectron spectroscopy, it was; confirmed that MnO nanoparticles were homogeneously dispersed on NG; surface. The density functional theory calculations demonstrated that; the superior electrochemical performance of MnO/NG might be attribute to; the exposure of stoichiometric MnO (100) surface, with the ORR and OER; overpotential only to be 0.21 and 0.24 V, respectively. The; discharging-charging voltage gap is 0.45 V, in good agreement with the; experimental value of 0.52 V.国家重点基础研究发展计划; 国家自然科学基金; 国家基础科学人才培养基

Formation of SEI layer on LiCoO_2 electrode and the Li ion diffusion kinetics

[中文文摘]用SEM和EIS法研究了LiCoO2材料表面SEI膜的形貌特征及锂离子在其中的扩散动力学行为。SEM结果表明:化成后的LiCoO2材料表面存在SEI膜,其形貌和厚度与溶剂密切相关,在PC溶剂中形成的SEI膜要比DMC溶剂中形成的薄。EIS结果显示:锂离子在SEI膜中的扩散过渡时间比在LiCoO2材料中小1个数量级,但是扩散系数却小3~4个数量级。[英文文摘]The morphological character of the SEI layers formed on the surface of LiCoO2 and the Li ion diffusion kinetics in it were studied by the methods of SEM and EIS.The result of SEM indicated that the SEI layer was found on the surface of LiCoO2 after formation,its morphology and thickness were closely related with the solvent,the SEI layer formed in PC solvent was thinner than that formed in DMC solvent.The result of EIS showed that the Li ion diffusion transition time in SEI film was shorter for 1 order of magnitude than in LiCoO2 material , but its transfer diffusion coefficient was smaller for 3～4 orders of magnitude。973项目(2002CB211807); 福建省化学电源科技创新平台(2006H0090)

香炉山钨矿残采区地压灾害微震监测技术应用分析

香炉山钨矿东区形成了形状复杂、体积巨大的采空区,地压灾害问题突出。为了确保矿山生产安全,该矿成功地建立了国内最大、最先进的48通道全数字型微震监测系统。本文简要介绍了多通道微震监测系统的组成、传感器的优化布置,分析了微震监测系统对微震事件的定位误差和效果;论文进一步对采区内微震定位事件、非定位事件进行了初步的应用研究;论文还对西区大爆破对东区地压的影响程度进行了监测。最后,论文对井下岩体破裂类型与释放的弹性波波形进行了辨识与频谱分析。初步的地压微震监测与分析结果表明,微震监测技术能对香炉山钨矿残采区进行动态的地压监测,可以预见该技术将在今后的矿山安全管理中起到更加重要的作用

The applied development of ferrate used as cathode materials

介绍了高铁酸盐的研究发展概况。结合高铁酸盐在水溶液体系和非水溶液体系电池中的应用,对将其作为一种新型正极材料的电化学特性进行了讨论。The recent development survey of ferrate was reviewed especially as cathode materials in batteries. The application as active materials in aqueous and non-aqueous battery system was presented. It was shown that the ferrate could be used as cathode active material in alkaline Zn/ferrate( Ⅵ), MH/ferrate(Ⅵ㈡) and lithium batteries and possessing of higher capacity than Zn/MnO? and Li/LiMn2O4 batteries respectively. However the stability of these batteries was not satisfactory due to the characteristics of ferrate. It would be key work to improve the stability of ferrate ongoing process

Study on overcharging additives of Li-ion battery

[中文文摘]环己基苯和二甲苯作为耐过充添加剂加入锂离子电池电解液中。环己基苯和二甲苯分别在4.70 V、4.66 V(vs.Li/Li+)处发生电聚合反应。聚合物几乎全部覆盖在隔膜表面,阻断了反应,改善了电池的安全性。添加5%添加剂的电池,均可耐3C1、0 V过充电,且对电池正常充放电时的电化学性能影响很小。[英文文摘]Cyclohexyl benzene(CB) and xylene as overcharging additives were added into Liion battery electrolyte.CB and xylene could be electrochemically polymerized at 4.70 V and 4.66 V(vs.Li/Li~+),respectively.The polymer mainly deposited on the separator,restrained the reaction and improved the safety performance of the battery.The batteries with the additives could resist overcharge of 3 C,10 V when the content of additive was 5%.There was only a slight influence on the electrochemical performance of the batteries with normal charge-discharge.973项目(2002CB211800); 国家自然科学基金(20373058)；厦门市科技计划项目(3502Z20055018)

Development progress of low-temperature lithium-ion batteries

综述了低温锂离子电池近几年的研究进展。对比分析了不同溶剂、电解质及添加剂对锂离子电池低温性能的影响及作用机理,同时也讨论了低温环境中电极结构与表面反应对锂离子电池低温性能的影响。综合近年来的发展趋势,指出了低温锂离子电池的发展方向。The development of low temperature lithium ion batteries in recent years was reviewed. The influence and its mechanism of different solvents,salts and additives of low temperature electrolyte were compared,the electrode structure and electrode surface reaction in low temperature environment were also discussed. Some directions of research on low temperature lithium batteries were presented according to recent developing trend.浙江省技术创新项目资助(2007-50);; 杭州市高技术产业化项目资助(2007-13

Preparation of potassium diformate by methyl formate and potassium hydroxide

联系人：李清彪. 第一作者：詹国武（1986—），男，学士.[中文文摘]本研究采用甲酸甲酯、氢氧化钾、甲酸为原料，一步反应制备二甲酸钾。系统地考察了影响产品收率的主要因素，优化了工艺条件，结果表明，当n(MF)/n(KOH)=1.20，n(HCOOH)/n(KOH)=1.44，反应时间为30min，反应温度为55℃时，二甲酸钾产品收率可达 98.8%。产品经红外光谱分析及成分测定，符合质量标准。[英文文摘]In this study, methyl formate, potassium hydroxide and formic acid were used as raw materials for one-step synthesis of potassium diformate. The main factors affecting the quality and yield of product were investigated. The optimal conditions for reaction were: molar ratio of MF to KOH 1.20:1, molar ratio of HCOOH to KOH 1.44:1, reaction time 30 min and reaction temperature 55℃. The product met the quality standard of potassium diformate after infrared spectrum analysis and composition determination.厦门大学创新性实验计划资助项