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排序方式: 共有149条查询结果,搜索用时 15 毫秒
131.
LI Wenyan LI Yanzi LIU Jiadi CHAO Shen YANG Tianyi LI Lijuan WANG Ce LI Xiang 《高等学校化学研究》2021,37(3):496-504
Lead ion(Pb2+) is one of the most hazardous heavy metal ions in aquatic environments. Carbon materials and manganese dio-xide(MnO2) have been shown to be prospective adsorbents to cope with the lead pollution. In this study, a novel hollow carbon@MnO2 composite nanofiber adsorbent was prepared by the combination of electrospinning and carbonization. The PAN nanofiber membrane is subjected to a pre-oxidation and carbonization process, and then the obtained carbon nanofibers react with KMnO4 solution during the hydrothermal process to develop the hollow carbon@MnO2 nanofibers. The hollow carbon@MnO2 nanofibers displayed a higher adsorption capacity of Pb2+ than carbon and MnO2/PDA/PAN nanofibers. The maximum adsorption capacity toward Pb2+ by hollow carbon@MnO2 nanofibers was 460.83 mg/g. After 5 adsorption-desorption cycles, the carbon@MnO2nanofibers had a good recyclability and the removal efficiency remained 81.47%. Moreover, the removal efficiency of the hollow composite nanofibers for Pb2+ from real wastewater could reach 94.37%. This work shows a strategy for synthetics of the hollow carbon@MnO2 nanofibers, which exhibits a promising potential in actual wastewater treatment. 相似文献
132.
Liu Jing Ma Li Li Yang Zuo Xiaobin Gao Yuan Wang Tao Zhang Yan Liu Haibin Wang Jiabo Niu Ming Liu Shijing Xiao Xiaohe 《Journal of Thermal Analysis and Calorimetry》2020,139(2):1141-1149
Journal of Thermal Analysis and Calorimetry - Colla corii asini (CCA) is a widely used animal-derived traditional medicine and nutritional supplement in China that has a variety of bioactive... 相似文献
133.
计算机单缝衍射光强分布曲线的拟合 总被引:1,自引:0,他引:1
先将单缝衍射光强分布的实验数据用五点三次平滑处理,以减少误差。再用牛顿插值求出光强分布公式中的单缝宽度。从而用计算机得出拟合曲线。 相似文献
134.
Nano-Li3V2(PO4)3/C Synthesized by Thermal Polymerization Method as Cathode Material for Lithium Ion Batteries 下载免费PDF全文
Bin Cheng Lian-sheng Jiao Zhong-feng Tang Sheng-jie Zhang Hong-li Chen Chun-hua Chen 《化学物理学报(中文版)》2016,29(6):699-702
A nano-Li3V2(PO4)3/C powder was successfully prepared by a thermal polymerization method. The particle sizes of the intermediate product powder and the final product Li3V2(PO4)3 are all less than 200 nm. The carbon is partially coated on the surface of Li3V2(PO4)3 particles and the rest exists between particles with a total carbon content of 4.6wt%. This nano-Li3V2(PO4)3/C sample shows a discharge capacity of 124 mAh/g without capacity fading after 100 cycles at 0.1 C in the voltage rang of 3.0-4.3 V. Excellent rate performance is also achieved with a capacity of 80 mAh/g at 20 C in 3.0-4.3 V and 100 mAh/g at 10 C in 3.0-4.8 V. This study suggests that the thermal polymerization method is suitable to synthesize nano-Li3V2(PO4)3/C materials. 相似文献
135.
136.
手性胺-质子酸是近年来发展起来的新型高效、高对映选择性的有机催化体系, 已成功应用于催化不对称Aldol反应、Michael加成反应、Diels-Alder反应和Strecker反应等许多重要的有机合成反应. 价廉易得的质子酸的引入不仅可促进活性中间体烯胺的生成, 并可通过形成的氢键稳定反应的过渡态, 从而显著提高该催化体系的催化活性和立体选择性. 对各类手性胺-质子酸催化剂在有机催化不对称合成反应中的应用、不对称诱导反应的机理、手性胺和质子酸的分子结构对其催化活性和不对称诱导活性的影响进行了评述. 相似文献
137.
Jinlong Gong Xinbin Ma Xia Yang Shengping Wang Shoudong Wen 《Reaction Kinetics and Catalysis Letters》2005,84(1):79-86
Summary The effect of Mo loadings and preparation methods, slurry and conventional impregnation, on the performances of alumina-supported MoO3 catalysts in transesterification of dimethyl oxalate (DMO) with phenol was investigated. Slurry prepared MoO3/-Al2O3 catalyst exhibited higher activity and dispersion capacity than conventional one. Slurry MoO3/water was used instead of an ammonium heptamolybdate solution. Highly dispersed amorphous Mo catalysts were obtained, closely related to the catalytic activities without calcination, waste solutions, and calcining nitrogenous gases. 相似文献
138.
Yu Zhang Haijun Xing Piaoping Yang Peng Wu Mingjun Jia Jiazhong Sun Tonghao Wu 《Reaction Kinetics and Catalysis Letters》2007,90(1):45-52
Pillared layered MCM-36 zeolite was prepared from MCM-22 precursor with polymeric silica as pillaring agent. Both MCM-36 and
MCM-22 zeolites are very active for the alkylation of benzene with propylene, and MCM-36 shows higher selectivity to cumene
compared with MCM-22 zeolite. 相似文献
139.
《Electrochemistry communications》2007,9(5):1180-1184
Net-structured NiO was prepared by urea-mediated homogeneous hydrolysis of Ni(CH3COO)2 under microwave radiation followed by a calcination at 500 °C. NiO–C nanocomposite was prepared by dispersing the as-prepared net-structured NiO in glucose solution and subsequent carbonization under hydrothermal conditions at 180 °C. The carbon in the composite was amorphous by the X-ray diffraction (XRD) analysis, and its content was 15.05 wt% calculated according to the energy dispersive X-ray spectroscopy (EDX) result. Transmission electron microscopy (TEM) image of the NiO–C nanocomposite showed that the NiO network was homogeneously filled by amorphous carbon. The reversible capacity of NiO–C nanocomposite after 40 cycles is 429 mAh g−1, much higher than that of NiO (178 mAh g−1). These improvements are attributed to the carbon, which can enhance the conductivity of NiO, suppress the aggregation of active particles, and increase their structure stability during cycling. 相似文献
140.
采用密度泛函理论(DFT)的B3LYP泛函, 在6-311G*水平上对B2Cn+(n=1~9)团簇的几何构型和电子结构进行了优化和振动频率计算. 结果表明, 在B2Cn+(n=1~9)团簇的基态构型中, B2C2+、B2C3+为具有D∞h对称性的线形结构, B2C7+为具有Cs对称性的立体环状结构, 其余均为平面构型; 其成键顺序为C—C成键优于B—C 成键, B—C成键优于B—B成键. 进一步得到了B2Cn+(n=1~9)团簇的总能量(ET)、零点能(EZ)、摩尔热容(Cp)、标准熵(S0)以及原子化能(ΔEn+). 其结果显示, 随着n的递增, ET、EZ、Cp、S0和ΔEn+数值均呈现增大趋势, 其中EZ数值呈现近似等梯度的增加趋势. 通过对B2Cn+(n=1~9)团簇基态结构的垂直电子亲合势的研究发现, n为奇数的B2Cn+团簇比n为偶数的稳定. 相似文献