锌离子荧光探针研究进展

锌广泛存在于人体内,具有重要生理功能。因此,对游离锌离子的选择性识别和有效检测具有重要意义。荧光探针因其设计简单、易于操作、灵敏度高、可细胞成像等诸多优点而广泛应用于锌离子的识别研究。锌离子荧光探针常见的识别机理包括光致电子转移、分子内电荷转移、荧光共振能量转移、聚集诱导荧光增强、螯合荧光增强等。其中,基于螯合荧光增强机理的锌离子探针,其荧光团通常可同时作为识别基团,因此,相比于其它探针,具有设计较为简单、合成较为便捷的优点。本文综述了近年来文献中报道的基于以上各种识别机理的锌离子荧光探针,并着重介绍了螯合荧光增强机理在锌离子识别中的应用。     

标准模型下基于格的代理环签名方案

代理环签名是一种特殊的数字签名,可以广泛地应用于很多生活领域.但是现有的代理环签名方案的安全性大都是在随机预言模型下证明的,在实际应用中不一定安全.提出一个标准模型下基于格的代理环签名方案,同时,基于格上的难题SIS和ISIS,证明了方案能够抵抗存在性伪造攻击.     

MoS2/Cd2SnO4复合材料的制备及其气敏性能

采用水热-煅烧法制备Cd₂SnO₄,之后通过超声混合法得到一系列MoS₂/Cd₂SnO₄复合材料。采用X射线衍射、扫描电子显微镜、X射线光电子能谱对Cd₂SnO₄和一系列MoS₂/Cd₂SnO₄复合材料进行结构和形貌的表征。研究了MoS₂掺杂量对于MoS₂/Cd₂SnO₄复合材料的气敏性能影响。实验结果表明,当MoS₂与Cd₂SnO₄的质量比为2.5%,MoS₂/Cd₂SnO₄复合材料制备的气敏元件在170 ℃时对浓度为100 μL·L^-1的甲醛气体的灵敏度为40.0,最低检测限为0.1 μL·L^-1。     

光谱法研究有机农药污染物与DNA的相互作用

利用紫外光谱、荧光光谱及圆二色谱(CD)等光谱方法研究了有机农药敌敌畏(DDVP)、乐果(DIM)、氧化乐果(OME)及生物农药申嗪霉素的有效成分吩嗪-1-羧酸(PCA)与端粒脱氧核糖核酸(DNA)间的相互作用。 结果表明,有机农药分子可能主要以嵌入模式与DNA结合,DDVP、DIM、OME以及PCA与端粒DNA之间的表观结合常数分别为：1.17×106、1.48×106、4.52×105和1.80×106 L/mol,与DNA结合能力的大小顺序为PCA＞DIM＞DDVP＞OME。 这些有机农药分子明显不利于DNA双螺旋结构的稳定性。 有机农药分子的嵌入削弱了DNA碱基对之间的π-π堆积作用,对DNA的二级结构有一定的影响,使得DNA的双螺旋结构变得松散。     

盐湖资源开发利用进展

本世纪头十年里,国际上再度掀起盐湖资源开发热潮。这很大程度上是由于锂的开发热带动的,同时也是和钾肥的广泛施用、价格一路走高有关。南美安第斯高原地区盐湖蕴藏世界70%以上的锂资源,且卤水锂、钾、硼浓度高。该地区极度干旱,少雨多风,非常适合采用卤水盐田蒸发的节能浓缩工艺技术。老的盐湖开发企业则在钾肥需求的带动下,稳步发展。在我国,新疆罗布泊和青海柴达木盆地盐湖则钾锂镁硼产品多元化,经营多元化取得长足进步。本文对近十年来,国内外盐湖开发的新动向做了概括介绍,特别着重于南美"锂三角"地区这一新的生长点。     

Operator-Valued Fourier Multipliers on Multi-dimensional Hardy Spaces

The author establishes operator-valued Fourier multiplier theorems on multi-dimensional Hardy spaces H ^p ($ \mathbb{T} $ \mathbb{T} ^d ;X), where 1 ≤ p < ∞, d ∈ ℕ, and X is an AUMD Banach space having the property (α). The sufficient condition on the multiplier is a Marcinkiewicz type condition of order 2 using Rademacher boundedness of sets of bounded linear operators. It is also shown that the assumption that X has the property (α) is necessary when d ≥ 2 even for scalar-valued multipliers. When the underlying Banach space does not have the property (α), a sufficient condition on the multiplier of Marcinkiewicz type of order 2 using a notion of d-Rademacher boundedness is also given.     

一类离散的时滞脉冲切换系统的H_∞二次稳定性

研究了一类离散的时滞脉冲切换系统的H_∞控制问题,利用Lyapunov稳定性理论和线性矩阵不等式方法,给出了离散脉冲切换系统具有性能指标γ的充分条件.     

Highly sensitive detection of silybin based on adsorptive stripping analysis at single-sided heated screen-printed carbon electrodes modified with multi-walled carbon nanotubes with direct current heating

A new disposable multi-walled carbon nanotubes modified single-sided heated screen-printed carbon electrode (MWNT/ss-HSPCE) was fabricated. The electrochemical behavior of silybin was investigated by cyclic voltammetry and the probable electrode reaction mechanism was proposed. A simple and cheap direct current heating supplier was used to heating the electrode for adsorptive accumulation of silybin. The square wave voltammetric stripping peak current of silybin at MWNT/ss-HSPCE with an elevated electrode temperature of 50 °C only during accumulation step was dramatically improved compared with that at bare single-sided heated screen-printed carbon electrode (ss-HSPCE) without heating. This enhancement was mainly contributed to the combination of the advantages of multi-walled carbon nanotubes and electrically heated electrodes. Under optimum conditions, two detection linear ranges of silybin were from 1.0 × 10⁻⁹ to 1.0 × 10⁻⁷ M and 3.0 × 10⁻⁷ to 1.0 × 10⁻⁶ M. A detection limit of 5.0 × 10⁻¹⁰ M could be obtained (S/N = 3), which was more than two magnitudes lower than that at bare ss-HSPCE without heating. To the best of our knowledge, this was also at least two magnitudes lower than any others for electrochemical detection of silybin in the literature. Finally, the method was successfully applied to the determination of silybin in pharmaceutical tablets.     

An involution on increasing trees

We introduce a method to construct bijections on increasing trees. Using this method, we construct an involution on increasing trees, from which we obtain the equidistribution of the statistics ‘number of odd vertices’ and ‘number of even vertices at odd levels’. As an application, we deduce that the expected value of the number of even vertices is twice the expected value of the number of odd vertices in a random recursive tree of given size.     

广元千佛崖石窟石刻彩妆颜料的分析

四川省广元千佛崖石窟是四川境内最大的石窟寺和摩崖造像群,承载着古代社会的历史信息,对研究当时的政治、文化和社会生活意义重大。千佛崖石窟在自然环境因素的长期作用下,目前受到多种严重病害的侵蚀,亟待保护。为了获取石刻彩妆的成分与工艺信息以支撑彩妆的保护工作,应用X射线衍射分析、剖面显微分析、扫描电镜能谱分析、激光拉曼光谱分析等方法,对广元千佛崖8处洞窟的已脱落彩妆颜料层样品进行了分析。X射线衍射分析鉴定出了铁红(Fe₂O₃)、朱砂 (HgS)、铅丹(Pb₃O₄)、炭黑等颜料成分,以及铅白 (PbSO₄)、石膏(CaSO₄·2H₂O)、长石、二氧化硅等打底层和岩体的组分,验证了样品脱落的原因是岩体的劣化。剖面显微分析和扫描电镜能谱分析表明,不同洞窟的彩妆制作工艺有区别,有的颜料直接施加在岩体表面,有的则在颜料层和岩体间有一层主要为硫酸铅的打底层;样品表面蓝绿色颜料的含量很少,仅通过激光共聚焦显微拉曼光谱成功地识别出来,其鉴定结果为蓝铜矾[Cu₄SO₄(OH)₆·2H₂O]。蓝铜矾作为颜料使用的报道很少。由于其矿物含量较少但分布广泛,古代一般不将其分离出来单独使用,而人工合成的碱式硫酸铜类颜料布勒门绿（Bremen green）出现于18世纪-19世纪,如果有纯碱式硫酸铜单独使用的情况出现,就意味着有近现代重绘的可能性,将有助于彩绘类文物保存历史的判断。该研究不仅为千佛崖石刻彩妆的保护提供了依据,丰富了文化遗产中使用蓝铜矾颜料的案例,更对彩妆的保存历史研究有潜在价值。