Synchronous determination of mercury (II) and copper (II) based on quantum dots-multilayer film

A sensitive sensor for mercury (II) and copper (II) synchronous detection was established via the changed photoluminescence of CdTe quantum dots (QDs) multilayer films in this work. QDs were deposited on the quartz slides to form QDs-multilayer films by electrostatic interactions with poly(dimethyldiallyl ammonium chloride) (PDDA). Hg²⁺ or Cu²⁺ could quench the photoluminescence of the QDs-multilayer films, and glutathione (GSH) was used to remove Hg²⁺ or Cu²⁺ from QDs-multilayer films due to strong affinity of GSH-metal ions, which resulted in the recovered photoluminescence of QDs-multilayer films. There are good linear relationships between the metal ions concentration and the photoluminescence intensity of QDs in the quenched and recovered process. It was found that the Stern–Volmer constants for Hg²⁺ are higher than that for Cu²⁺. Based on different quenching and recovery constant between Hg²⁺ and Cu²⁺, the synchronous detection of Hg²⁺ and Cu²⁺ can be achieved. The linear ranges of this assay were obtained from 0.005 to 0.5 μM for Hg²⁺ and from 0.01 to 1 μM for Cu²⁺, respectively. And the artificial water samples were determined by this method with satisfactory results, the recoveries for Hg²⁺ and Cu²⁺ ions were found in the range of 90.4–106.4%. To the best of our knowledge, it is the first report about the synchronous detection of Hg²⁺ and Cu²⁺ by using quenched and recovered photoluminescence of quantum dots multilayer films.     

Nile Red Synchronous Scan Fluorescence Spectroscopy to Follow Matrix Modification in Sol–Gel Derived Media and its Effect on the Peroxidase Activity of cytochrome <Emphasis Type="Italic">c</Emphasis>

The highly solvatochromic dye Nile red is used in conjunction with synchronous scan fluorescence spectroscopy to elucidate changes in the internal environment of cytochrome c, upon incorporation into differently modified sol–gel derived media. Nile red was first studied in a variety of solvents in order to quantify changes in polarity. Matrix modifications involved the addition of several silanes, intended to interact with any unreacted hydroxyl entities left from the matrix forming reaction, while polymers were used to help reduce shrinkage and modify the internal pore environment. Slight unfolding of the protein was observed on incorporation into the sol–gel derived media. During the aging process further changes were monitored by using difference synchronous scan fluorescence spectra and complementary measurements of catalytic activity, expressed as the initial velocity. Combining Nile red synchronous scan fluorescence with cytochrome c activity data lead to a method to elucidate effects linked to protein conformation and those related to the sol–gel derived host. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

基于Serial RapidIO的高速实时数据采集处理系统

首先分析了传统共享型总线在高速实时数据采集处理系统中应用的局限性,介绍了新型交换式串行总线的优势。在对比当前流行的四种新型交换式高速串行总线特点的基础上,分析了采用Serial RapidIO技术架构系统的优势,设计了一个基于这一技术的高速实时数据采集处理系统。该系统具有易扩展、易升级的特点,具有较高的实际应用价值。     

多环芳烃混合物的快速同步荧光光谱分析

建立了胶束溶液中多环芳烃混合物同时测定的同步荧光分析法.该法简便快速,无需对混合物进行分离,可实现11种组分的同时鉴别和定量测定.方法的检出限在0.013～3.2 ng·mL-1之间,相对标准偏差为1.05%～1.45%.此方法应用于分析河水、池塘水、污水中多环芳烃均取得了良好的效果,回收率分别为80.4%～115%、83.4%～101%和80.5%～95.9%.     

罗丹明B-Mn2+-H2O2体系同步荧光分光光度法测定中药的抗氧化活性

罗丹明B能产生特征荧光,其激发波长和发射波长分别为554 nm和575 nm。弱碱性介质中Mn2 -H2O2体系产生的羟自由基可迅速氧化罗丹明B使荧光猝灭,而中药水提取物可部分清除溶液中羟自由基,从而使其荧光猝灭程度减弱。用Δλ=21 nm的同步荧光分光光度法建立了测定中药抗氧化活性的方法。测试了11种中药的抗氧化活性,以五倍子的抗氧化活性最强。     

一种基于FDTD算法的局域导波端口激励

为弥补传统导波端口在处理辐射问题的缺陷,解决导波端口后向泄漏和远场外推面截断而导致的辐射失真等问题。该文深入研究时域有限差分算法中导波端口激励的加载方式,首次提出了一种通用有效的局域导波端口,并对端口中各边界条件的参数配置和实现方法进行了深入论述。此外,利用该算法对不连续性波导、微带贴片天线和波导缝隙天线阵等实际问题进行了模拟仿真,结果表明,在处理波导不连续性问题时,该方法保持很高的计算精度;在处理导波端口的辐射问题时,传统方法存在较大误差,新方法则能取得很好的计算结果。因此该方法不仅适用于模拟导波端口激励的辐射问题,也适用于分析各类波导不连续性问题,具有普适性。     

瑞利衰落环境中二维扩频矩阵的序贯捕获性能分析

该文给出了一种二维扩频矩阵的时间同步方法,分析了此方法的捕获概率和虚警概率;在不同归一化门限条件下,给出了数值结果。分析结果表明,经映射的二维扩频系统等效为一维扩频系统,采用一维扩频的同步方法能使二维扩频系统获得良好同步性能,且方法简单。     

合成孔径雷达实时转置存储的实现

本文介绍了如何利用同步动态内存(SDRAM)实现合成孔径雷达实时成像处理器转置存储中数据转置的功能,重点论述了带有自动预充电功能的SDRAM控制器的设计以及刷新控制电路、地址产生电路的实现过程。     

光谱法研究Cu2+诱导的不同时间的LDL体外氧化

氧化低密度脂蛋白(oxidized low density lipoprotein,oxLDI)被认为是动脉硬化的关键致病因素.文章综合运用紫外吸收光谱、荧光光谱、同步荧光光谱及圆二色(circular diclaro‘lsm.CD)光谱研究了(好'诱导不同时间的U)IJ体外氧化过程.随着氧化时间的增加.生成的丙二醛(malonaldehyde,MDA)的量逐渐增加,其相对应的430 nm 处的荧光强度也随之加强,氧化过程中生成了新的氧化产物.氧化低密度脂蛋白紫外吸收增强;表征氨基酸残基信息的特征荧光强度和同步荧光强度降低;载脂蛋白B-100(apolipoproteinB-100,apoB-100)α-螺旋含量减少.实验结果表明,LDL氧化过程中Cu2+不仅诱导了氧化产物的生成,而且改变了apoB-100的构象进而导致了生色基团的微环境的变化.     

光谱法研究染料木素与人血清白蛋白的相互作用

用荧光猝灭光谱、同步荧光光谱和紫外-可见吸收光谱研究了染料木素与人血清白蛋白(HSA)的相互作用。结果表明染料木素对HSA的荧光猝灭作用属于二者形成复合物所引起的静态猝灭;利用Stern-Volmer方程处理实验数据,得到染料木素与HSA之间的结合常数K_A为1.00×106(27 ℃),1.66×106(37 ℃)和5.25×106(47 ℃)。根据Frster非辐射能量转移理论,求出了染料木素与HSA之间的结合距离为2.59 nm(27 ℃),2.65 nm(37 ℃)和2.90 nm(47 ℃)。通过计算热力学参数,可知该药物与人血清白蛋白的相互作用是一个吉布斯自由能降低的自发过程,且二者之间的主要作用力类型为静电引力,同时用同步荧光光谱探讨了染料木素对HSA构象的影响。