A solvent-governed surface state strategy for rational synthesis of N and S co-doped carbon dots with multicolour fluorescence

ABSTRACT

Multicolour emissive carbon dots (CDs) are widely investigated by virtue of their merits on fluorescent properties. Method on heteroatom doping assisted with various solvents has been proved efficient in achieving multiple-colour-emissive CDs, especially long-wavelength emission. Herein, a synthesis of multicolour-emissive CDs by controlled surface function is reported. By tuning the thermal-pyrolysis temperature and molar ratio of reactants, optimal emission of the resulted CDs gradually shifts from blue to yellow light with the assistance of different solvents. According to the emissive relationship dependent on excitation, fluorescence lifetimes, and FT-IR of these CDs, the different surface states participated with S and N elements on the surface of carbogenic core govern fluorescent colours of the CDs. In terms of the applications, blue CDs (B-CDs) exhibits high sensitivity for ion detections of Ag⁺ and Fe³⁺, which is further illustrated to have different quenching mechanisms each other because that these ions have the affinity interaction with different surface groups of the CDs. Moreover, blue and yellow CDs solutions are mixed with PVP water solution to fabricate white-light CDs/PVP film, which exhibits stable fluorescence with a CIE coordinate of (0.32, 0.33) and endows these CDs as potentially fluorescent nanomaterial in the solid state lighting field.     

细胞松弛素B阻断微核法鉴定男性个体辐射敏感性的方法初探

初步研究了男性个体辐射敏感性的鉴定方法及标准。采集50名男性志愿者的外周血，分别给予不同剂量X射线照射，采用细胞松弛素B阻断双核法测定微核率(MNF)，通过二阶多项拟合法，绘制微核剂量效应选项中心标准曲线，将个人微核剂量效应曲线与标准曲线比对后判断个体辐射敏感性。 $0.0\sim2.5 $ Gy剂量范围内，剂量效应二阶多项拟合的中心方程为(MNF=0.014 7+0.036 2D+0.023 1D 2， r=0.726)。50名志愿者中，辐射敏感的有13人，辐射抗性的有14人，基本符合正态分布。Spearman秩和相关分析结果显示，MNF在各个辐射剂量点与辐射敏感性均存在正相关,与辐射抗性呈负相关,MNF随剂量增加而增加。本研究初步建立了“以线代点”男性个体辐射敏感性鉴定方法,并发现男性外周血淋巴细胞的本底微核率与个体辐射敏感性呈正相关。     

固相烧结法制备锂离子电池正极材料Li2FeP2O7及其电化学性能研究

介绍了一种先冷冻干燥后固相烧结制备正极材料Li₂FeP₂O₇的方法. 利用X射线衍射(XRD)、 扫描电子显微镜(SEM)、 透射电子显微镜(TEM)和傅里叶变换红外光谱(FTIR)对材料的组成和形态进行表征, 并通过循环伏安曲线(CV)和电化学阻抗谱(EIS)研究了Li₂FeP₂O₇材料的电化学性能. 研究发现, 合成Li₂FeP₂O₇的最佳温度为590 ℃, 此温度下反应较完全且产物杂质较少, 1.6C倍率下的放电比容量达到55 mA·h·g^?1, 明显高于其它温度下合成样品的放电比容量. 该温度下合成的Li₂FeP₂O₇还具有低阻抗和较大的交换电流密度, 说明这种合成方式有利于提高锂离子在Li₂FeP₂O₇中的扩散.     

两种缓冲材料的应力松弛实验分析

 用逐次残余法分析了聚乙烯和聚苯乙烯缓冲材料的应力松弛试验数据．结果表明可用有限个并联的Ｍａｘｗｅｌ模型来表示这两种材料的应力松弛试验曲线．     

新组合模型在光电功率预测中的应用

为提高光伏预测要求的精准性,文章提出一种新算法将神经网络和ARMA算法改进组合,构成NEW ARMA-BP模型算法.以某30兆瓦的光伏电站采集的输出功率为输入样本,基于ARMA和BP神经网络算法在Matlab环境下依次搭建了相应的预测模型,预估光伏短期输出量.采用"误差正态检验图"判断基于两种不同算法的误差水平,依据两种单模型预测误差,运用所提出的新方法计算权值并获得新的预测值.基于Matlab的仿真结论验证了组合预测在光伏输出预测领域的适用性.     

Platinum nanoclusters on graphite substrates: a molecular dynamics study

Molecular dynamics simulations are used to investigate the shape and structure evolution of single platinum clusters of cubic and spherical shape containing 256 and 260 atoms, respectively, deposited on a static graphite substrate. The evolution is monitored at variable temperature, and as a function of metal-substrate interactions at constant temperature. The Pt-Pt interactions are modelled with the many-body Sutton-Chen potential, whereas a Lennard-Jones potential is used to describe the Pt-C interactions. Heating and cooling curves calculated between 200 K and 1800 K are used to determine solid-solid and solid-liquid transitions. Structural changes are detected through analyses of density profiles and diffusion coefficients. A clear analogy is observed between temperature-induced wetting phenomena and those resulting from enhancement of the metal-substrate interactions.     

AuNPs/Sol-gel复合膜法固定乙酰胆碱酯酶生物传感器检测有机磷农药

基于有机磷农药对乙酰胆碱酯酶(Acetylcholinesterase,AChE)的抑制作用,用金纳米粒子(Au nanoparticles,AuNPs)与壳聚糖/SiO2杂化溶胶-凝胶构成复合固酶基质,将AChE固定于玻碳电极表面,制备了电流型AChE生物传感器选用久效磷进行实验,以氯化硫代乙酰胆碱为底物,建立了电化...     

POINCAR SERIES AND AN APPLICATION TO WEYL ALGEBRAS

Let A n be the n-th Weyl algebra over a field of characteristic 0 and M a finitely generated module over A n . By further exploring the relationship between the Poincar′e series and the dimension and the multiplicity of M , we are able to prove that the tensor product of two finitely generated modules over A n has the multiplicity equal to the product of the multiplicities of both modules. It turns out that we can compute the dimensions and the multiplicities of some homogeneous subquotient modules of A n .     

热分析联用技术及其在金属材料领域中的应用

热分析联用技术是在热重分析基础上,将多种检测手段并用,准确地研究材料的结构、组成、热反应等特性,从而揭示材料热分解过程本质的技术。在程序升温过程中,利用热分析联用技术对金属材料的质量和热量变化及热分解产物成分等信息进行检测,能更精准地研究金属材料的组成和热分解特性。该文在热重分析法的基础上,着重介绍了其与差热分析、差示扫描量热分析、傅里叶红外光谱分析、质谱分析等分析方法的联用,并以金属材料研究为例,分析了热分析联用技术在金属材料的结构、性能测定等方面的应用,同时展望了热分析联用技术的应用前景。