Graphene Quantum Dots Enhanced Electrochemical Performance of Polypyrrole as Supercapacitor Electrode

通过将吡咯单体在低温下与石墨烯量子点进行原位聚合，获得一种全新的聚吡咯/石墨烯量子点（PPY/GQD）复合材料. 实验中采用了扫描电子显微镜（SEM）、原子力显微镜（AFM）、X射线衍射(XRD)、红外（FT-IR）和热重（TGA）对复合物的表面形貌、结构进行表征. 结果表明，吡咯单体以石墨烯量子点为软模板，以化学键的方式在石墨烯量子点的表面聚合生长成片状聚吡咯. 通过机械冷压法将粉末状PPY/GQD复合物压成圆片电极，电极的电化学测试结果表明，PPY和GQD质量比为50:1所制得的复合物的电容量为485 F·g-1，同时在两千次循环之后电容量只降低了大约2%. 通过与同比例的PG（聚吡咯/石墨烯复合材料）以及纯PPY对比，发现聚吡咯/石墨烯量子点的高比容量及优异的循环稳定性将会使其在电化学超级电容器领域中具有的潜在的应用价值.With an objective to develop electrode materials with high specific capacitance and good stability, a completely new nanocomposite of Polypyrrole (PPY) and graphene quantum dots (GQD) was successfully obtained through in-situ polymerization of pyrrole in the presence of GQD suspension. The obtained composites with different mass ratios were characterized by X-Ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). GQD enhanced electrochemical performance of PPY and, as supercapacitor electrodes, the PPY/GQD composites with the mass ratio of PPY to GQD at 50:1 showed a competitive specific capacitance of 485 F·g-1 at a scan rate of 0.005 V·s-1. The attenuation of the specific capacitance is about 2% after 2000 cycles. The high specific capacitance and good stability of the PPY/GQD nanocomposites are promising for applications in electrochemical supercapacitors.This work was supported by the National Natural Science Foundation of China (No. 20906055), National “973 Program” (No. 2010CB933900), and the State Key Laboratory of Bioreactor Engineering (No. 2060204).This work was supported by the National Natural Science Foundation of China (No. 20906055), National “973 Program” (No. 2010CB933900), and the State Key Laboratory of Bioreactor Engineering (No. 2060204).作者联系地址：上海交通大学微纳科学技术研究院，上海 200240Author's Address: Key Laboratory for Thin Film and Microfabrication of the Ministry of Education, Research Institute of Micro/Nano Science and Technology, Shanghai Jiao Tong University, Shanghai 200240, China通讯作者E-mail：[email protected]

Research on the Method of Arc Welding Robot Pose Precision Reliability Analysis Based on D-H Model

提高焊接工业机器人位姿精度可靠性是现代焊接机器人技术发展中的一个重要课题。位姿精度可靠性的影响因素具有随机性,属于随机变量,位姿精度研究应从概率的观点进行可靠性分析。本文提出了弧焊机器人位姿精度可靠性分析方法,该方法基于D-H模型,运用位姿误差矩阵法和Monte Carlo随机抽样仿真技术,能够得到末端位姿误差分布,计算给定误差极限条件下的可靠度,能够较正确客观地评价机器人位姿精度可靠性

在线微柱富集纳升液相色谱-串联质谱法测定大鼠脑组织中类固醇激素

类固醇激素对脑功能的调节越来越受到人们的关注,但其在脑组织中极其微量而且脑组织样品量相对少,这对检测方法提出了更高的挑战。本研究优化了脑组织中提取类固醇激素的预处理方法,发现乙醇的提取效果最好。经过固相萃取柱进一步纯化的样品,基质干扰明显减少。采用75μm内径的C18捕集柱和分析柱,通过阀切换连接,构建了在线微柱富集纳升液相色谱分析系统,结合纳喷离子源串联质谱法实现高灵敏检测脑组织中类固醇激素。系统考察了方法的精密度、定量曲线、回收率等分析特性。日内和日间精密度分别在4.5%～12.8%和8.3%～20.3%之间。除了孕酮略有离子抑制外,其它激素基质效应不明显,而且低、中、高3个浓度下的回收率基本都在60%～115%之间。不同类固醇激素的检出限差异较大,在0.02～10μg/L之间。与常规尺寸液相色谱-质谱系统相比,相同进样量下,该方法的灵敏度显著提高了57～714倍,同时流动相消耗量降低了几百倍。将本方法用于大鼠脑组织中类固醇激素的检测,检测到4种类固醇激素,分别为睾酮（Testosterone）0.47 ng/g,肾上腺酮（Corticosterone）26.2 ng/g,醛甾酮（Aldosterone）0.49 ng/g和皮质醇（Hydrocortisone）0.06 ng/g。本方法具有灵敏度高、样品需要量少和溶剂消耗少等优势,可用于生物组织样品中类固醇激素的测定

Electrochemical Performances of Layered Polypyrrole/Chemically Reduced Graphene Oxide Nanocomposites as Supercapacitor Electrodes

论文通过将吡咯单体在低温下与氧化石墨烯进行原位聚合，获得聚吡咯/石墨烯（Ppy/CRGO）复合材料. 采用场发射电子显微镜（FESEM）、红外 (FT-IR)和热重 (TGA)对复合物的表面形貌、结构进行表征. FESEM结果表明，通过控制氧化石墨烯（GO）和吡咯单体的质量比例，可以对复合物的层状和厚度进行调控. FT-IR和TGA结果表明聚吡咯（Ppy）是通过化学键合的方式与氧化石墨烯复合在一起。通过机械冷压法将粉末状Ppy/CRGO复合物压成圆片电极，并探讨了石墨烯和聚吡咯复合比例、反应时间、烘干温度、孔隙率等因素对Ppy/CRGO复合物电极的电学和电化学性能的影响. 结果表明，Ppy与CRGO质量比为10:1所制得的Ppy/CRGO复合物的电容量为421 F?g-1，通过在电极中引入孔隙，电容量能进一步提升为509 F?g-1.Nanocomposites of polypyrrole (Ppy) and chemically reduced graphene oxide (CRGO), Ppy/CRGO, have been fabricated through in-situ polymerization of pyrrole on graphene oxide (GO) sheets. The as-synthesized Ppy/CRGO composites were characterized complementarily using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transformed infrared spectroscopy (FT-IR). By controlling the initial ratio of the GO to pyrrole, the layered composites could be obtained and their thickness could be tuned properly. The Ppy/CRGO electrodes were prepared using a mechanical compressing technique and their electrical conductivity and electrochemical properties were characterized systematically. We demonstrated that as electrodes for supercapacitor, the Ppy/CRGO composites with Ppy to CRGO ratio of 10:1 showed a competitive capacitance of 421 F?g-1 that could be further increased to 509 F?g-1 by introducing pores in it, which is higher than that of Ppy alone. Given the manifest electrical and electrochemical properties, we envisage that the Ppy/CRGO composites should find applications in supercapacitors.This work was supported by the National Natural Science Foundation of China (No. 20906055), National “973 Program” (No. 2010CB933900) and the State Key Laboratory of Bioreactor engineering (No. 2060204).作者联系地址：上海交通大学微纳米科学与技术研究院，上海 200240Author's Address: National Key Laboratory of Micro/Nano Fabrication Technology, Key Laboratory for Thin Film and Microfabrication of the Ministry of Education, Research Institute of Micro/Nano Science and Technology, Shanghai Jiao Tong University, Shanghai 200240, China通讯作者E-mail：[email protected]

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies