通过溶液水解反应在氧化石墨烯表面引入氧化锡(Sn O2)纳米颗粒,再经过自组装作用形成具有三维结构的氧化锡/石墨烯水凝胶(Sn O2-GH)负极材料。其中三维多孔的石墨烯水凝胶为碳质缓冲基体,Sn O2纳米颗粒为活性物质,其颗粒尺寸为2-3 nm,...通过溶液水解反应在氧化石墨烯表面引入氧化锡(Sn O2)纳米颗粒,再经过自组装作用形成具有三维结构的氧化锡/石墨烯水凝胶(Sn O2-GH)负极材料。其中三维多孔的石墨烯水凝胶为碳质缓冲基体,Sn O2纳米颗粒为活性物质,其颗粒尺寸为2-3 nm,均匀分布在石墨烯层上,担载量可以达到54%(w,质量分数)。直接将该材料用作锂离子电池负极时,在5000 m A?g^(-1)的大电流密度下循环60次容量稳定在500 m Ah?g^(-1),电流减小到50 m A?g^(-1)循环80次后容量仍高达865 m Ah?g^(-1)。这些优异的循环稳定性和大电流充放电性能主要得益于三维石墨烯水凝胶的疏松、多孔结构和良好的导电性。石墨烯水凝胶能够提高电极比表面积,保证电解液对电极的浸润程度;内部空隙能够为锂离子的传输提供快速通道,缩短离子传输距离和时间。同时丰富的内部空间能够有效避免Sn O2纳米颗粒团聚,缓冲Sn O2巨大体积膨胀,维持电极结构的稳定性,是一种非常适于大电流充放电的锂离子电池负极材料。展开更多
自从出现现代建筑以来,空间问题成为探寻建筑学本质问题的核心,由SOM(Skidmore,Owings and Merrill)建筑设计事务所设计的上海金茂大厦,是中国传统建筑风格与世界高新技术的完美结合。文章试图从传统塔式空间类型的角度出发,通过分析金...自从出现现代建筑以来,空间问题成为探寻建筑学本质问题的核心,由SOM(Skidmore,Owings and Merrill)建筑设计事务所设计的上海金茂大厦,是中国传统建筑风格与世界高新技术的完美结合。文章试图从传统塔式空间类型的角度出发,通过分析金茂大厦的空间结构和空间操作方式,探究其空间结构的形式逻辑及规律。展开更多
SnO2/ graphite nanocomposites with different SnO2 contents were successfully prepared by a co-precipitation method.The nanocomposites, used as the anode material for lithium-ion batteries( LIBs),were characterized by ...SnO2/ graphite nanocomposites with different SnO2 contents were successfully prepared by a co-precipitation method.The nanocomposites, used as the anode material for lithium-ion batteries( LIBs),were characterized by X-ray diffraction( XRD),thermogravimetric analysis( TGA), and transmission electron microscopy( TEM). The SnO2 particles had the average size of about 15 nm and their distribution on graphite matrix much depended on the contents of SnO2 in the nanocomposites. The galvanostatic charge-discharge cycles were used to investigate the effects of SnO2 contents on the electrochemical performance of these composites. The results show that the initial specific capacities increase with the SnO2 contents. However,the cyclic stabilities are determined by the distribution of SnO2 particles in composites. For55% by weight SnO2/ graphite composites, the initial specific capacity is 740 m Ah g- 1and 70% of the initial specific capacity( 518 m Ah·g- 1) can still be retained after 50 charge-discharge cycles.展开更多
Poly[ 2, 2-（m.phenylene） -5, 5-bibenzimidazole] （mPBI） were synthesized by mixing 3, 3＇, 4, 4＇-tetraaminobiphenyl and isophthallc acid in 1 -butyl-3 -methyUmidazolinm chloride （ E BMIM] CI）. Intrinsic viscosit...Poly[ 2, 2-（m.phenylene） -5, 5-bibenzimidazole] （mPBI） were synthesized by mixing 3, 3＇, 4, 4＇-tetraaminobiphenyl and isophthallc acid in 1 -butyl-3 -methyUmidazolinm chloride （ E BMIM] CI）. Intrinsic viscosity of mPBI polymers was 0.67 dL/g which was measured in 96% sulfuric acid. The polymer was characterized by Fourier transform infrared spectroscopy （FTIR）, nuclear magnetic resonance （ 1H-NMR ）, and thermogravimetric analysis （TGA）. The effects of polymerization conditions on the intrinsic viscosity of mPBI were investigated. It showed that the molecular weight of polymer mainly depended on pre-reaction time and reaction temperature. Comparison of structure and properties of mPBI synthesized in ionic liquids（ILs） and polyphosphoric acid was also reported. It indicates that the ionic liquids are a kind of good solvents in synthesis process of m_PBI and ionic liquids mainly affect molecular weight of mPBL展开更多
目的探讨Meckel憩室的患病情况、临床特点及腹腔镜下Meckel憩室切除术的临床应用价值。方法分析1例腹腔镜Meckel憩室切除术患者的病例资料。结果手术顺利,术中无并发症、死亡和中转开腹,术后7 d出院,出院3个月后随访无特殊不适。结论 M ...目的探讨Meckel憩室的患病情况、临床特点及腹腔镜下Meckel憩室切除术的临床应用价值。方法分析1例腹腔镜Meckel憩室切除术患者的病例资料。结果手术顺利,术中无并发症、死亡和中转开腹,术后7 d出院,出院3个月后随访无特殊不适。结论 M e c k e l憩室症状无特异性,临床上多以并发症就诊,如憩室炎、消化道出血、肠梗阻及肠穿孔。内窥镜检查、选择性肠系膜血管造影、放射性核素显像、腹腔镜检查是M e c k e l憩室的主要诊断方法,对怀疑M e c k e l憩室,辅助检查无法明确诊断时腹腔镜检查可以进行诊断。腹腔镜下M e c k e l憩室切除创伤小,操作简单,治疗效果满意,且能提高小肠疾病诊断的准确性,临床应用前景广阔。腹腔镜手术与传统手术相比优点很多:患者腹部切口小;术后疼痛减轻;术后胃肠道功能恢复较快;术后切口愈合时间短;术后恢复正常活动较快;患者自身免疫受影响较小。因此腹腔镜技术在小肠疾病的临床应用值得广泛推广。展开更多
文摘通过溶液水解反应在氧化石墨烯表面引入氧化锡(Sn O2)纳米颗粒,再经过自组装作用形成具有三维结构的氧化锡/石墨烯水凝胶(Sn O2-GH)负极材料。其中三维多孔的石墨烯水凝胶为碳质缓冲基体,Sn O2纳米颗粒为活性物质,其颗粒尺寸为2-3 nm,均匀分布在石墨烯层上,担载量可以达到54%(w,质量分数)。直接将该材料用作锂离子电池负极时,在5000 m A?g^(-1)的大电流密度下循环60次容量稳定在500 m Ah?g^(-1),电流减小到50 m A?g^(-1)循环80次后容量仍高达865 m Ah?g^(-1)。这些优异的循环稳定性和大电流充放电性能主要得益于三维石墨烯水凝胶的疏松、多孔结构和良好的导电性。石墨烯水凝胶能够提高电极比表面积,保证电解液对电极的浸润程度;内部空隙能够为锂离子的传输提供快速通道,缩短离子传输距离和时间。同时丰富的内部空间能够有效避免Sn O2纳米颗粒团聚,缓冲Sn O2巨大体积膨胀,维持电极结构的稳定性,是一种非常适于大电流充放电的锂离子电池负极材料。
文摘自从出现现代建筑以来,空间问题成为探寻建筑学本质问题的核心,由SOM(Skidmore,Owings and Merrill)建筑设计事务所设计的上海金茂大厦,是中国传统建筑风格与世界高新技术的完美结合。文章试图从传统塔式空间类型的角度出发,通过分析金茂大厦的空间结构和空间操作方式,探究其空间结构的形式逻辑及规律。
基金the Scientific Research Foundation for the Returned Overseas Chinese Scholarsthe Shanghai Leading Academic Discipline Project,China(No.B603)the Programme of Introducing Talents of Discipline to Universities,China(No.111-2-04)
文摘SnO2/ graphite nanocomposites with different SnO2 contents were successfully prepared by a co-precipitation method.The nanocomposites, used as the anode material for lithium-ion batteries( LIBs),were characterized by X-ray diffraction( XRD),thermogravimetric analysis( TGA), and transmission electron microscopy( TEM). The SnO2 particles had the average size of about 15 nm and their distribution on graphite matrix much depended on the contents of SnO2 in the nanocomposites. The galvanostatic charge-discharge cycles were used to investigate the effects of SnO2 contents on the electrochemical performance of these composites. The results show that the initial specific capacities increase with the SnO2 contents. However,the cyclic stabilities are determined by the distribution of SnO2 particles in composites. For55% by weight SnO2/ graphite composites, the initial specific capacity is 740 m Ah g- 1and 70% of the initial specific capacity( 518 m Ah·g- 1) can still be retained after 50 charge-discharge cycles.
基金Natural Science Foundation of Shanghai,China(No.09ZR1401500)
文摘Poly[ 2, 2-（m.phenylene） -5, 5-bibenzimidazole] （mPBI） were synthesized by mixing 3, 3＇, 4, 4＇-tetraaminobiphenyl and isophthallc acid in 1 -butyl-3 -methyUmidazolinm chloride （ E BMIM] CI）. Intrinsic viscosity of mPBI polymers was 0.67 dL/g which was measured in 96% sulfuric acid. The polymer was characterized by Fourier transform infrared spectroscopy （FTIR）, nuclear magnetic resonance （ 1H-NMR ）, and thermogravimetric analysis （TGA）. The effects of polymerization conditions on the intrinsic viscosity of mPBI were investigated. It showed that the molecular weight of polymer mainly depended on pre-reaction time and reaction temperature. Comparison of structure and properties of mPBI synthesized in ionic liquids（ILs） and polyphosphoric acid was also reported. It indicates that the ionic liquids are a kind of good solvents in synthesis process of m_PBI and ionic liquids mainly affect molecular weight of mPBL
文摘目的探讨Meckel憩室的患病情况、临床特点及腹腔镜下Meckel憩室切除术的临床应用价值。方法分析1例腹腔镜Meckel憩室切除术患者的病例资料。结果手术顺利,术中无并发症、死亡和中转开腹,术后7 d出院,出院3个月后随访无特殊不适。结论 M e c k e l憩室症状无特异性,临床上多以并发症就诊,如憩室炎、消化道出血、肠梗阻及肠穿孔。内窥镜检查、选择性肠系膜血管造影、放射性核素显像、腹腔镜检查是M e c k e l憩室的主要诊断方法,对怀疑M e c k e l憩室,辅助检查无法明确诊断时腹腔镜检查可以进行诊断。腹腔镜下M e c k e l憩室切除创伤小,操作简单,治疗效果满意,且能提高小肠疾病诊断的准确性,临床应用前景广阔。腹腔镜手术与传统手术相比优点很多:患者腹部切口小;术后疼痛减轻;术后胃肠道功能恢复较快;术后切口愈合时间短;术后恢复正常活动较快;患者自身免疫受影响较小。因此腹腔镜技术在小肠疾病的临床应用值得广泛推广。
