Silylated BODIPY dyes and their use in dye-encapsulated silica nanoparticles with switchable emitting wavelengths for cellular imaging

Two silylated BODIPY derivatives were synthesized, characterized and used for the fabrication of the dye-encapsulated silica nanoparticles. The fluorophores were covalently incorporated into the silica matrix to minimize any fluorophore leakage. The synthesized fluorophore-doped nanoparticles were stable in aqueous solution and monodisperse with diameters of 20-25 nm. By incorporating the two BODIPY dyes simultaneously at a controlled ratio, silica nanoparticles with switchable emitting wavelengths were achieved with a change in the excitation wavelength. Thus by using the dual-fluorophore-doped nanoparticles, two-color imaging was demonstrated with minimal background signal by employing an appropriate excitation light source and appropriate excitation/emission filter sets. Further, the surfaces of the dual-fluorophore-doped nanoparticles were functionalized with folic acid to allow for the recognition of HeLa cells which over-express the folate receptors.     

Existence and uniqueness result for a class of sequential fractional differential equations

In this paper, we consider the following sequential fractional differential equation with initial value problem: where 0<????1 and f:[0,1]×?×???? is continuous. Existence and uniqueness results of solutions are established.     

碳钢/醇酸涂层在5%NaCl溶液中的极化及半导体行为

摘要 采用电位-电容测试和Mott-Schottky分析技术研究了碳钢/醇酸涂层在5%NaCl溶液侵蚀下腐蚀失效过程中的极化及半导体行为. 浸泡2h, 电极形成了MIS结构, 涂层半导体为n型导电, 半导体载流子密度为4.99×109cm-3, 腐蚀仅受水和离子在涂层中的扩散控制;浸泡1d和2d时, 涂层在电场下发生偶极极化, 偶极电场阻碍载流子的迁移, 偶极弛豫效应使微分电容随外加电位绝对值增大而减小, 并造成电位-电容行为的频率依赖性;浸泡7d~17d涂层发生空间电荷极化, 碳钢与涂层形成了金属/半导体接触, 随着浸泡时间延长, 涂层载流子密度逐渐增加, 平带电位正移, 功函数逐渐减小, 对电子束缚能力减弱, 随外加电位的增加, 金属/醇酸涂层界面势垒升高, 空间电荷层成为阻挡层, 电极载流子输运受涂层孔隙电阻, 空间电荷层, 金属基底反应动力学三重控制.     

ZnO-Bi2O3二元陶瓷粉体电化学行为研究

采用电化学阻抗谱和电位-电容测试及Mott-Schottky分析技术研究了ZnO-Bi2O3粉体电极在0.5 mol/L NaCl溶液中的电化学行为. 研究表明, ZnO-Bi2O3粉体表现为n型半导体; 随着Bi2O3含量的增加或混合时间的延长, 粉体的阻抗增大, 空间电荷层电容Csc减小, 载流子浓度ND减小; 经高温烧结成二元压敏陶瓷, 随着混合时间的延长, 电阻片综合电性能越好. 该方法可有效评价二元陶瓷粉体混合均匀性.     

各种网格上统一的数值离散方法

提出一种在任意网格上计算数值微分的方法，这种方法利用各种不同网格所具有的共同性质， 基于Taylor展开和加权最小二乘法，得到了各种网格下都可以使用的数值微分格式. 有了这一技术， 可以极大地丰富已经发展起来的各种数值方法，原来只能用在结构网格上的格式，可以直接推广到 其他各种网格上，从而可以用于各种复杂区域内微分方程的数值求解. 初步的应用表明这种技术是 简单而有效的.     

铅铋合金中金 、银分析取样方法的研究

围绕取样代表性和样品加工均匀性等问题,研究了铅铋合金锭中金银分析试样加工粒度对金银品位的影响,锭内金银分布及规律。通过对铅铋合金锭中金、银分布情况的研究结果,制定了铅铋合金锭的采样、样品加工及化验分析方案。     

Reduced CuFe2O4 for catalytic oxidation of methyl orange by activation of persulfate: performances and mechanisms

Research on Chemical Intermediates - Bimetallic Fe0-based catalysts have been shown to be effective heterogeneous catalysts for elimination of organic pollutants by activating persulfate (PS). In...     

分布轴向力作用下隔水管横向自由振动分析

隔水管固有频率的精确计算对保证隔水管的安全使用和防止共振的发生有着极为重要的意义.在分析中,考虑了分布轴向力和顶张力的共同作用,建立了隔水管横向振动力学模型;基于牛顿定律和纵横弯曲梁理论,对微单元受力分析,得到隔水管横向自由振动的四阶偏微分方程;利用分离变量法将四阶偏微分方程简化为四阶变系数常微分方程;采用积分法求解四阶变系数常微分方程,得到隔水管横向自由振动固有频率的解析解.结果表明:(1)分布轴向力作用下隔水管横向自由振动的固有频率和振型,与将分布轴向力简化为集中力作用下隔水管的固有频率和振型有很大差别;(2)顶张力一定时,随着分布轴向力减小,隔水管固有频率增大;分布轴向力一定时,随着顶张力增大,隔水管固有频率增大;(3)采用积分法求解隔水管横向振动特性时,计算精度高,为隔水管的优化设计提供了可靠的理论依据.     

Novel fluorophore based on a multi-substituted olefin skeleton with enhanced three-photon absorption in the femtosecond regime

A new multipolar fluorophore based on a multi-substituted olefin skeleton that possesses strong three-photon absorption and optical-limiting properties in the femtosecond regime has been designed and synthesized; this archetype suggests a new strategy to further optimize molecular structures toward enhanced nonlinear absorptivities based on known materials.     

多烯和花菁染料分子设计及其非线性光学性质研究进展

根据一种新的增强分子非线性光学性质的设计思想 ,讨论了多烯和花菁染料的结构和性质关系 ,综述了这类染料的非线性光学性质及其应用进展 ,并对有机非线性光学材料的发展前景进行了预测。