钠离子和钾离子通道噪声扰动对神经网络 时空模式的影响

研究了钠离子和钾离子通道噪声扰动对Hodgkin-Huxley神经网络放电时空模式的影响. 发现无论钠离子通道噪声还是钾离子通道噪声扰动, 当取定一组温度、噪声强度, 随着耦合强度的增大, 神经网络放电时空斑图总能演化出螺旋波, 而且存在形成螺旋波所需的临界耦合强度. 分析发现钠离子通道噪声有利于神经网络螺旋波的形成, 而钾离子通道噪声不利于螺旋波形成. 结果还表明较低的温度能够使神经网络对噪声更加敏感. 最后, 讨论了特定参数下螺旋波与靶波之间的转化现象.     

卡托普利的单扫描示波极谱测定

基于卡托普利在汞电极上有良好的电化学特性,以汞电极为工作电极,高氯酸为支持电解质,用单扫描示波极谱法测定了片剂、尿液及血清中卡托普利含量。结果表明,本法是测定微量卡托普利含量的一种灵敏、快速而简便的方法。     

基于碳纳米管的纳米连接技术的研究进展

纳米连接技术是构筑纳电子器件的关键技术。但鉴于目前纳米连接机理不甚明确、纳米连接技术不甚成熟,阻碍了纳电子器件的进一步研制和应用。因此如何形成碳纳米管与金属电极间可靠、稳定、有效的互连已成为该领域的研究难点和热点。本文综述了近年来改善纳米连接性能的多种方法,并对其原理和特点进行了分析和比较。最后,对该领域未来发展的趋势进行了展望。     

光催化还原制备Au/Ag核壳结构纳米粒子及其修饰电极的电催化性能

以Keggin结构硅钨杂多酸H4SiW12O40(SiW12)为光催化还原剂,通过光化学还原法制备Au/Ag核壳结构纳米粒子. 透射电子显微镜分析显示,所得纳米粒子粒径为30～40 nm,呈均匀分散的球形颗粒,该制备方法的特点是可以较好的避免单金属纳米粒子的形成. 将Au/Ag核壳纳米粒子修饰到具有PVP膜的玻碳电极表面,得到SiW12-(Au/Ag)-PVP多层膜修饰电极. 该修饰电极在0.5 mol/L H2SO4介质中具有良好的电化学响应,在0～-0.75 V电位范围内,出现了3对归属于SiW12的氧化还原峰,且电极性能稳定,灵敏度高. 对H2O2的电催化还原性能明显优于单金属Ag纳米粒子修饰电极,说明Au核的存在可以很好的改善Ag的电催化性能,Au和Ag之间存在相互协同催化作用.     

水油两相体系生物还原-化学沉淀耦合反应制备纳米二硫化锡

针对Sn4+易于水解而难以在水相稳定存在的不利条件,尝试了在水油两相体系中应用生物转化-化学沉淀耦合反应工艺制备SnS2纳米材料。研究了水油两相体系制备SnS2的优化条件,并借助XRD、SEM、EDS表征了制备材料的结构、形貌和物相。研究表明,生物水相pH值7、水油两相反应温度35℃,油相Sn4+与水相SO42-之物质的量浓度比1∶2的条件下有利于SnS2的生成。制备的SnS2为纳米片花瓣,纳米片平均厚度约为30 nm,花状微晶直径约1~5μm,纯度高,无杂质。     

Photothermal biological effects of monomeric erythrocyte using optical tweezers

The changes of mechanical properties and biological activities of monomeric erythrocytes are studied using optical tweezers micromanipulation technology. Firstly, the mechanical properties of irradiated erythrocyte membranes are obtained. Weaker power laser irradiation can delay the decay of the mechanical properties of erythrocytes and promote the biological activity of erythrocytes, while higher power laser irradiation damages erythrocytes. The stronger the laser irradiation is, the more obvious and rapid the damage will be. The temperature of the cell surface will be changed by regulating the laser power and irradiation time, so the biological functions of erythrocyte can be controlled. Secondly, the finite element simulation of the temperature change on the cell surface under the condition of laser irradiation is carried out using simulation software, and the precise temperature of the cell surface irradiated cumulatively by a laser with different powers is obtained. Finally, the processes of abscission, unfolding, and denaturation of hemoglobins in erythrocytes at different temperatures due to the photothermal effect are analyzed using the model. The mechanism of laser irradiation on the elasticity of erythrocyte membranes is also obtained.     

FcBAK/钼磷酸电荷转移型杂化分子的合成及性能

二茂铁衍生物l-二茂铁基3-苯基丙-2-烯-1-酮(FcBAK)与钼磷酸盐Na2HPMo12O40·xH2O经室温固相合成得到有机-无机杂化分子, 通过元素分析、IR、ICP、AAS和TG等表征手段确证产物的分子组成和结构为(FcBAK)3HPMo12O40·2H2O. 固体电子光谱及ESR谱表明, FcBAK与钼磷酸之间发生了电荷转移作用, 生成电荷转移型有机-无机分子复合物, 该复合物的磁学行为表现出较强的铁磁性质, 粉末样品的室温饱和磁化强度为0.41 A·m2/kg, 矫顽力为0.0105 T, 属于软磁性有机-无机分子复合材料.     

中性微乳液介质增敏鲁米诺电化学发光研究

磷酸盐缓冲的中性溴化十六烷基三甲基铵-正戊醇-正庚烷微乳液介质体系对鲁米诺的电化学发光有显著的增敏作用,本文对此增敏作用进行了研究,并在此介质体系中采用电化学发光淬灭法测定了生物活性分子褪黑素,此法可用于测定脑白金胶囊中的褪黑素。     

高灵敏银纳米棒阵列对农药啶虫脒的表面增强拉曼散射快速检测

The determination of pesticide residue on agricultural products is increasingly important.Exposure to pesticides can cause severe acute reactions in humans,including aplastic anemia and leukemia.In this work,we developed a rapid and sensitive method to detect acetamiprid pesticide residue based on surface-enhanced Raman scattering.Silver nanorod (AgNR) arrays were fabricated by oblique angle deposition technology and were used as SERS substrates.Prior to detection,the AgNR arrays were cleaned with nitric acid solution or a mixture of methanol and acetone.Compared to the unwashed AgNR arrays,the AgNR arrays washed with methanol and acetone shows a signal enhancement 1000 times greater than the unwashed AgNR array due to the effective removal of the impurities on its surface.The limit of detection of acetamiprid was determined to be 0.05 mg/L.In addition,the molecular structure of acetamiprid was simulated and the corresponding vibration modes of the characteristic bands of acetamiprid were calculated by density function theory.To demonstrate its practical application,the AgNRs array substrates were applied successfully to the rapid identification of acetamiprid residue on a cucumber''s surface.These results confirmed possibility of utilizing the AgNRs SERS substrates as a new method for highly sensitive pesticide residue detection.     

基于多壁碳纳米管化学修饰电极直接测定饮料中的麦芽酚

采用循环伏安法和示差脉冲伏安法研究了麦芽酚在多壁碳纳米管修饰电极上的电化学行为,建立了一种直接测定饮料样品中麦芽酚含量的电分析测试方法. 在pH=8.5的NH3 ·H2 O-NH4 Cl 缓冲溶液中,麦芽酚在多壁碳纳米管修饰电极上于0.55 V(vs.SCE)产生不可逆的氧化峰. 该修饰电极对麦芽酚的电化学反应具有促进作用,阳极峰电流与溶液中麦芽酚的浓度成正比,线性范围为5.0×10-6～9.0×10-4mol/L,检出下限为2.0×10-6mol/L.对含5.0×10-5mol/L的麦芽酚溶液平行测定10次的相对标准偏差(RSD)为1.1%.多壁碳纳米管修饰电极具有良好的电极稳定性,可用于饮料样品中麦芽酚的直接测定,避免了繁复费时的样品前处理过程. 将该修饰电极用于啤酒、可乐和葡萄酒样品中麦芽酚测定,回收率为98%～103%.