纳米磷酸铁锂的制备及电化学性能研究

利用液相沉淀法合成了纳米级磷酸铁,并以此为铁源,通过碳热还原技术制备了粒径均匀的纳米级球形LiFePO4/C正极材料。经热分析(TG-DSC)、X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)以及恒电流充放电测试,研究了纳米磷酸铁及纳米磷酸铁锂材料的结构、形貌以及电化学性能。实验结果表明材料的首次放电比容量达161.8 mAh.g-1(0.1C),库仑效率为98.3%;室温下在0.2C、0.5C、1C、2C及5C倍率充放电其首次放电比容量分别为156.5、144、138.9、125.6和105.7 mAh·g-1,材料具有较好的倍率性能。     

Theoretical study of determining orientation and alignment of symmetric top molecule using laser-induced fluorescence

General expressions used for extracting the orientation and alignment parameters of a symmetric top molecule from laser-induced fluorescence (LIF) intensity are derived by employing the density matrix approach. The molecular orientation and alignment are described by molecular state multipoles. Excitation and detection are circularly and linearly polarized lights, respectively. In general cases, the LIF intensity is a complex function of the initial molecular state multipoles, the dynamic factors and the excitation-detection geometrical factors. It contains a population, ten orientation and fourteen alignment multipoles. The problem of how to extract the initial molecular state multipoles from the resolved LIF intensity is discussed.     

Zn2GeO4纳米棒的制备及发光性质

采用水热合成法制备了纯菱形相的Zn₂GeO₄纳米棒,研究了水热制备前驱体溶液的pH值对材料尺寸及形貌的影响以及Zn₂GeO₄纳米棒的光学性质。扫描电子显微镜（SEM）测试结果表明,随着前驱体溶液pH值的变化样品逐渐由微米级块状结构生长成为纳米颗粒,并且进一步形成纳米棒结构。纳米棒的尺寸由长200 nm变化到500 nm。室温光致发光（PL）光谱中观察到位于450和530 nm两个不同的发光峰,其分别源于Zn₂GeO₄的不同缺陷能级。     

超细Cu-ZnO-ZrO2催化剂的制备及其催化CO2加氢合成甲醇的性能

 采用溶胶－凝胶法、共沉淀法和共沸蒸馏法制备了一系列不同粒度范围的超细Cu－ZnO－ZrO2催化剂,并应用BET,XRD,TEM和TPR等物理化学方法对催化剂的结构和物化性质进行了表征,同时考察了催化剂上CO2加氢合成甲醇的反应性能．结果表明,超细Cu－ZnO－ZrO2催化剂具有粒度小、颗粒分布均匀和稳定性好的特点,并发现超细Cu－ZnO－ZrO2催化剂比大颗粒的工业Cu－ZnO－Al2O3催化剂具有更高的催化活性,而且随着催化剂粒度的减小,甲醇合成活性进一步增大．研究还发现,ZrO2具有稳定反应活性中心的作用．     

Pushing Up Lithium Storage through Nanostructured Polyazaacene Analogues as Anode

According to the evidence from both theoretical calculations and experimental findings, conjugated ladder polymers containing large π‐conjugated structure, a high number of nitrogen heteroatoms, and a multiring aromatic system, could be an ideal organic anode candidate for lithium‐ion batteries (LIBs). In this report, we demonstrated that the nanostructured polyazaacene analogue poly(1,6‐dihydropyrazino[2,3g]quinoxaline‐2,3,8‐triyl‐7‐(2H)‐ylidene‐7,8‐dimethylidene) (PQL) shows high performance as anode materials in LIBs: high capacity (1750 mAh g^?1, 0.05C), good rate performance (303 mAh g^?1, 5C), and excellent cycle life (1000 cycles), especially at high temperature of 50 °C. Our results suggest nanostructured conjugated ladder polymers could be alternative electrode materials for the practical application of LIBs.     

具有可变抽样区间的Poisson EWMA控制图

传统的EWMA控制图通常都是针对计量型质量特性值的,而对于计数型质量特征值少有研究.设计了单位缺陷数服从Poisson分布的EWMA控制图,并对Poisson EWMA控制图进行了可变抽样区间设计,利用Markov chain方法计算了其平均报警时间,计算结果表明,所设计的动态Poisson EWMA控制图较Shewhart c-图和固定抽样区间的Poissin EWMA控制图能更好的监控过程的变化.     

S(1D)+D2反应的立体动力学理论研究

在ab initio 势能面上利用非含时量子反应散射理论研究了S(1D)+D2反应在散射能为22.18 kJ·mol-1时的立体动力学. 计算的微分反应截面呈现弱反对称的前向后向散射, 这一结果与以前的准经典结果和实验结果相一致. 态分辨的极化依赖的微分反应截面和极化参数显示产物极化并非各向异性分布, 这意味着在反应过程中由于势能面上存在一个深势阱从而形成了长寿命的复合物.     

Quantitative Analysis of Berberine in Processed Coptis by Near-Infrared Diffuse Reflectance Spectroscopy

The near-infrared（NIR） diffuse reflectance spectroscopy was used to study the content of Berberine in the processed Coptis. The allocated proportions of Coptis to ginger, yellow liquor or Evodia rutaecarpa changed according to the results of orthogonal design as well as the temperature. For as withdrawing the full and effective information from the spectral data as possible, the spectral data was preprocessed through first derivative and multiplicative scatter correetion（MSC） according to the optimization results of different preprocessing methods. Firstly, the model was established by partial least squares（PLS）; the coefficient of determination（R2） of the prediction was 0.839, the root mean squared error of prediction（RMSEP） was 0.1422, and the mean relative error（RME） was 0.0276. Secondly, for reducing the dimension and removing noise, the spectral variables were highly effectively compressed via the wavelet transformation（WT） technology and the Haar wavelet was selected to decompose the spectral signals. After the wavelet coefficients from WT were input into the artificial neural network（ANN） instead of the spectra signal, the quantitative analysis model of Berberine in processed Coptis was established. The R^2 of the model was 0.9153, the RMSEP was 0.0444, and the RME was 0.0091. The values of appraisal index, namely R^2, RMSECV, and RME, indicate that the generalization ability and prediction precision of ANN are superior to those of PLS. The overall results show that NIR spectroscopy combined with ANN can be efficiently utilized for the rapid and accurate analysis of routine chemical compositions in Coptis. Accordingly, the result can provide technical support for the further analysis of Berberine and other components in processed Coptis. Simultaneously, the research can also offer the foundation of quantitative analysis of other NIR application.     

短脉冲高剂量率γ射线源技术研究

 介绍了“强光一号”加速器产生宽度约20 ns的高剂量率脉冲γ射线的工作过程;分析了短脉冲γ射线源二极管的管绝缘体和真空磁绝缘传输线的结构与绝缘性能;说明了等离子体断路开关的工作特性;阐述了二极管工作阻抗和阴阳极的设计原则与设计参数。给出了不同短脉冲γ射线源的实验结果,得到了3种辐射参数：脉冲宽度约20 ns,辐射面积为2,30和100 cm²时,相应的辐射剂量率为10¹¹,0.7×10¹¹和10¹⁰ Gy/s。     

Adaptive brainstorm optimisation with multiple strategies

Brainstorm optimisation (BSO) algorithm is a recently developed swarm intelligence algorithm inspired by the human problem-solving process. BSO has been shown to be an efficient method for creating better ideas to deal with complex problems. The original BSO suffers from low convergence and is easily trapped in local optima due to the improper balance between global exploration and local exploitation. Motivated by the memetic framework, an adaptive BSO with two complementary strategies (AMBSO) is proposed in this study. In AMBSO, a differential-based mutation technique is designed for global exploration improvement and a sub-gradient strategy is integrated for local exploitation enhancement. To dynamically trigger the appropriate strategy, an adaptive selection mechanism based on historical effectiveness is developed. The proposed algorithm is tested on 30 benchmark functions with various properties, such as unimodal, multimodal, shifted and rotated problems, in dimensions of 10, 30 and 50 to verify their scalable performance. Six state-of-the-art optimisation algorithms are included for comparison. Experimental results indicate the effectiveness of AMBSO in terms of solution quality and convergence speed.