一类非线性中立型分数阶泛函微分方程正解的存在性(英文)

本文考虑一类非线性中立型分数阶泛函微分方程.利用锥拉伸与锥压缩不动点定理对问题进行讨论,得到了这类中立型分数阶泛函微分方程正解的存在性.     

裸玻碳电极直接电化学发光测定诺氟沙星含量

基于诺氟沙星能够显著增强过硫酸根的电化学发光信号,建立了一种灵敏、简便而且价廉的测定诺氟沙星含量的新方法。在最佳实验条件下,诺氟沙星浓度在0.141—6.33μg/mL范围内,与电化学发光信号强度呈良好的线性关系,线性回归方程为IECL=116.4+73.5CNFLX(μg/mL),r=0.9968,检出限为0.039μg/mL(S/N=3)。对4.22μg/mL的诺氟沙星平行测定11次,RSD为1.3%,表明该方法具有良好的重现性,并成功地应用于人尿样中诺氟沙星含量的测定。     

两步变温晶种法制备丝光沸石膜及其渗透汽化乙酸脱水性能

在水热晶种法基础上采用两步变温晶化以高水硅比(n_H2O/n_SiO2)稀溶液配方为合成液,研制用于渗透汽化(PV)乙酸脱水的丝光沸石膜(MOR膜),考察了变温晶化各段时间、水硅比与氟离子对MOR膜的形貌与分离性能的影响规律。结果表明：高温段晶化时间、水硅比与氟离子对MOR膜的形貌、结晶度和膜层厚度产生显著影响,并影响MOR膜渗透气化分离性能;在高温段(150℃)和低温段(120℃)的晶化时间分别为18和6 h,在水硅比为60且含氟离子体系中所制备的MOR膜的性能最佳,其对质量分数50%的乙酸水溶液的渗透通量和分离系数分别为1.45 kg·m^-2·h^-1和1 008。     

Resonant electron exchange scattering in late transition metal monoxides

Intra-atomic d-d transitions in NiO(100) and CoO(100) have been investigated with angle-resolved electron energy loss spectroscopy (EELS) at primary energies close to the metal 3s excitation threshold. Electron exchange scattering was found to be resonantly enhanced at the 3s threshold due to the temporary formation of a negative ion core state and its subsequent decay via Auger-like transitions. In both oxides the threshold is lowered several eV due to a strong electron- core hole interaction. Angle-dependent studies reveal a different dependency of exchange processes on the scattering angle as compared with nonresonant measurements and reveal a different angle dependence for each specific d-d transition. It is suggested that in these oxides large-angle single-step inelastic scattering contributes significantly to the EELS measurements in reflection mode.     

Low-applied Potential Non-enzymatic Glucose Sensor Based on Ultrathin 2-D CuS Nanowall Arrays

The 2-D nanostructure, due to unprecedented physical, electronic, and chemical properties, was widely dedicated to the zooms of electrocatalysis, batteries, supercapacitors, solar cells, photocatalysis and sensing platforms. Herein, we reported a sort of low-applied potential non-enzymatic glucose sensor, which used ultrathin 2-D CuS nanowall arrays (CuS-NWAs) fabricated directly onto fluorine-doped tin oxide glass by potentiostatically deposition approach. Meaningfully, the potentiostatical-deposition time can control precisely the frame of 2-D CuS-NWAs on size and thickness and assist to ferret out the growing mechanization by analyzing the copper valence. Then, CuS-NWAs-based non-enzymatic glucose sensor presented the high sensitivity (2610 μA mM⁻¹ cm⁻²), a low detection of 17 nM, fast respond time (1.5–6.2 s) and low detection limits (2.6–17.7 nM, S/N=3) regardless of an applied potential as low as 0.33 V (vs. Ag/AgCl), attributed to that the 2-D CuS-NWAs offer large active area with numerous exposed active points, a low-resistance electron-shuttling passage and door-opened glucose-diffusion channel. Additionally, it was found that the sensitivity of CuS-NWAs-based non-enzymatic glucose sensors can be optimized by altering electrodeposition duration for CuS-NWAs growth. Confirmedly, the 2-D CuS-NWAs can be promised as a new system for high-performance electrochemical sensors with excellent properties of selectivity, stability and reproducibility.     

EXISTENCE OF MILD SOLUTIONS TO SEMILINEAR FRACTIONAL ORDER FUNCTIONAL DIFFERENTIAL EQUATIONS

In this paper,we use the analytic semigroup theory of linear operators and fixed point method to prove the existence of mild solutions to a semilinear fractional order functional differential equations in a Banach space.     

臧红T-Fenton体系荧光光谱法测定黄山贡菊/金菊的抗氧化活性

臧红T能产生特征荧光,其激发波长和发射波长分别为264nm和577nm.酸性介质中,Fenton体系(H2O2-Fe2+)产生的羟自由基能氧化臧红T使其荧光猝灭,而许多花茶的提取物可部分清除溶液中的羟自由基使其荧光猝灭程度降低,据此建立了一种测定黄山贡菊和金菊的抗氧化活性的新方法.本实验采用单因素实验法,对羟自由基体系...     

红旱莲中异槲皮苷的提取纯化工艺

考察红旱莲中异槲皮苷的富集、纯化的工艺条件.通过聚酰胺树脂不同条件下对异槲皮苷的吸附与解吸附性能的研究,确定聚酰胺树脂对异槲皮苷的精制工艺条件,最佳条件是:上柱液中异槲皮苷浓度为1.176mg/mL、流速为3.6BV/h,以50％乙醇为洗脱溶剂,异槲皮苷比吸附量则达2.45mg/g.异槲皮苷提取率由2.83％提高到29.93％,聚酰胺树脂可用于红旱莲中异槲皮苷的分离富集.     

两个d10金属配位聚合物的合成、结构及对2,4,6-三硝基苯酚的选择性检测

以4,4''-二（1-咪唑基）苯硫醚（BIDPT）,4,4''-羧基二苯胺（H₂aba）,5-氧乙酸间苯二酸（H₃OABDC）,Zn（NO₃）₂·6H₂O和Cd（NO₃）₂·6H₂O为原料,用溶剂热法合成了2个配位聚合物[Zn（BIDPT）（aba）]_n（1）和[Cd（BIDPT）（HOABDC）]_n（2）。利用X射线单晶衍射、红外、元素分析、热重分析和X射线粉末衍射对其进行了表征。单晶X射线衍射研究发现配合物1为具有二重穿插的三维dia拓扑网络结构;配合物2为3-连接六边形的hcb二维拓扑结构,再通过氢键堆积作用形成三维超分子结构。1和2具有很好的荧光性质,硝基苯化合物对配合物1和2的荧光性质有不同程度的淬灭作用。它们都对2,4,6-三硝基苯酚的检测具有很好的灵敏性。对其淬灭机理进行了深入的研究。     

茶树叶与根表面的XPS表征

利用X射线光电子能谱(XPS)研究了茶树叶与根的表面化学组成与结构。结果表明,茶树表面主要由C, O, N和Al等四种元素组成,在茶树叶远轴面还有少量的P和F。通过查阅标准图谱数据库、参照木材表面XPS分析结果,对茶树表面测得的C1s结合能采用曲线拟合与分峰,得到三种形态：结合能为285 eV的是C1,来自C—C或C—H,代表角质、蜡质等脂类化合物;C2的结合能在286.35 eV（近轴面）和286.61 eV（远轴面）,是能够与氧形成单键的C—O,主要源于表面的纤维素;C3的结合能为288.04 eV（近轴面）和288.09 eV（远轴面）,为CO基团标志,综合N（1s）的结合能（399～401 eV）和O（1s）的分峰情况,为蛋白质的酰基标志。茶树根表面除含有与叶表面相同的C1(结合能285 eV)、C2（结合能286.49 eV）和C3（结合能288.78 eV）所代表的角质、蜡质、纤维素和蛋白质之外,还出现了结合能为283.32 eV的C5。由于其结合能低于C1,推测为茶树根表面的有机金属形态。茶树叶和根表面没有木材表面具有的羧基C4,说明根系分泌的有机酸游离存在于根表面。对茶树表面O（1s）图谱的拟合结果与C（1s）结果相吻合。计算不同C和O形态所占的比例得知,茶树叶面远轴面含氧基团多于近轴面,呈较高的氧化状态,因此远轴面化学性质较活泼;与叶相比,茶树根的角质和蜡质含量显著降低,含氧基团相对增多,因此化学性质较活泼,适于水分子和其他溶质分子通过。由于蛋白质含量为根表面＞远轴面＞近轴面,表明根表面的湿润度高于叶表面,而远轴面湿润度高于近轴面。存在于茶树表面Al的结合能均大于单质铝72.7 eV,在73.50 eV以上,为Al₂O₃形态,这将增大茶树表面的吸附作用。由于根表面Al₂O₃含量高于叶面,显示根具有更强的吸附能力。