金纳米锥阵列与金薄膜耦合结构表面等离子体折射率传感研究

设计了基于SiO₂薄膜间隔的金纳米锥与金薄膜耦合结构表面等离子体共振折射率传感器。使用时域有限差分法研究了复合结构中的表面等离子体共振模式,复合结构不仅能够激发局域表面等离子体共振,也可激发传播表面等离子体共振。入射电磁波的能量部分通过单个金纳米锥耦合到局域表面等离子体,部分通过金纳米锥阵列二维光栅耦合到传播表面等离子体。在待测物折射率1.30～1.40的范围内,对复合结构的反射光谱进行了模拟研究,发现共振波长与分析物折射率呈线性关系,且由于局域和传播表面等离子体的高效激发,反射光谱共振峰处的反射率几乎为零。此外,在最优的金纳米锥几何参数下,传播表面等离子体共振模式的半高全宽非常窄,灵敏度和品质因数分别达到770 nm/RIU和113 RIU^-1,具有良好的折射率传感性能。所设计的复合结构作为表面等离子体共振传感器有望广泛应用于生物检测领域。     

金纳米材料光学传感快速检测方法研究要点初探

基于金纳米材料光学性能优良、稳定性高以及易于表面功能化等特点而建立的纳米金光学传感检测方法,具有灵敏度高、准确、易操作、可视化和成本低等优点.金纳米材料类传感器是利用功能化纳米金与目标物之间发生相互作用,使得金纳米颗粒的尺寸、形状和聚集状态发生改变,从而引起溶液颜色、荧光和散射强度发生变化,为目标物的快速检测提供了出色的测定平台.为更好地介绍金纳米材料在现代检测领域的重要作用,本文首先总结了近年来出现的四种常见纳米金光学传感检测方法:纳米金聚集光学传感法、纳米金刻蚀光学传感法、纳米金荧光光学传感法、纳米金散射光学传感法.通过介绍这些方法的检测原理,探讨了其在化学、生物和环境领域的发展及应用.随后,通过分析四种策略的设计思路,初步总结出七个关于开发纳米金光学传感检测技术实验要点,分别是纳米金的合成与表面功能化、溶液pH、反应温度和反应时间、选择性、体系检出限、方法准确性、体系可重复利用性.通过详尽分析这些要点的重要性,为接下来从事相关领域研究的科研工作者提供实验设计思路和经验.最后,本文还探讨了目前基于纳米金光学传感检测方法所面临的一些主要挑战,并展望了该类方法在未来的发展方向.例如,通过将该类方法与智能手机、层析试纸条等技术相结合,实现检测过程的简单化、便携化.总体来说,基于金纳米材料的光学传感检测方法具有良好的发展前景.     

纳米金与生物分子的相互作用及生物传感检测

系统地分析了纳米金与生物分子的相互作用,并从光学比色分析、荧光分析、电化学检测、质量变化检测等几个方面入手,详细介绍了纳米金在DNA检测领域中的应用。     

乙醇对金属钯复合膜透氢性能影响的研究

利用化学镀的方法制备了不同厚度的钯膜,着重研究了乙醇水蒸气重整反应气氛下钯膜的透氢性能.实验结果表明:573~623K时,乙醇氢气混合气(Et/H2)气氛对钯膜透氢性能的影响大于乙醇水蒸气混合气(Et/H2O)气氛;623~673K时,Et/H2O气氛对钯膜透氢性能的影响大于Et/H2气氛.当钯膜暴露在H2/N2/Et和H2/N2/Et/H2O气氛下50min后,透氢量分别能恢复至初始值的96%和89%.此外,乙醇水蒸气重整反应气氛中,较大的水醇摩尔比[(10~13)∶1]和较薄的钯膜(2~6μm)有利于抑制钯膜透氢量的下降.     

超疏水还原氧化石墨烯/聚氨酯复合海绵的制备及其传感性能

在氧化石墨烯分散液中加入十二烷基糖苷作为发泡剂形成氧化石墨烯微泡团聚体,通过浸渍法与聚氨酯海绵骨架复合后经过液氮的极速冷冻以及肼蒸气的还原,构筑了一种有着特殊三维分级多孔结构兼具超疏水和柔性压阻传感性能的还原氧化石墨烯/聚氨酯复合海绵。结果表明：基于还原氧化石墨烯/聚氨酯复合海绵的柔性应力应变传感器的灵敏度系数（GF）最高可达3.8,响应时间低至45 ms;另外,还原氧化石墨烯/聚氨酯复合海绵还具有良好的超疏水性,水接触角（WCA）达152.5°,在潮湿及水下等复杂环境中具有潜在的应用价值。     

高Q值THz类EIT超材料及传感特性研究

设计了一种具有类电磁诱导透明(EIT)效应的高Q值太赫兹超材料。该结构单元由上下平行的双金属线及中间垂直的单金属线组成。分别对单金属线、双金属线及组合结构进行仿真,分析了组合结构中金属线的位置和尺寸对透射率及品质因数Q的影响。结果表明,随着单金属线的水平移动产生了类EIT效应,透射率和Q值随着偏移距离的增大而发生变化,通过调整结构和尺寸可以实现不同Q值。通过优化,当偏移距离为8 μm时,在0.73 THz附近得到一个3 dB带宽约为11.56 GHz的透明窗,相应的Q值为63.09,其透射率为0.50。最后,对谐振器的传感特性进行了测量,其折射率灵敏度为60.69 GHz/RIU,FOM值为5.25/RIU,具有优异的传感特性。     

3种不同导电纤维的大应变传感特性的比较研究

针对不同基体纤维,即PA6、Lycra和XLA,研究了3种具有PPy(聚吡咯)涂层的柔性导电纤维的大应变传感特性.导电纤维样品由化学气相沉积法制得;纤维的大应变传感特性实验在拉伸试验机下进行,同时记录下电阻随应变的变化.借助于SEM观测手段,得到了3种纤维的截面形状及纤维在加载条件下表面涂层形貌的微观图像,为分析纤维的...     

基于有源超材料的可调超薄雷达吸波体研究

在超材料结构中引入电阻和有源变容二极管,通过合理设计微结构型式以及微结构之间的连线方式,实现吸波频带的动态可调,研究电阻、电容和入射波极化方向对吸波特性的影响。结果表明:通过改变外加电压调整超材料的吸收频段,在3.7倍频带范围内实现吸波频段的主动自调节;吸波体的总厚度仅为波长的1/181,相比于传统吸波材料,在同等吸波性能条件下,表现出了优异的超薄特性;TE和TM极化电磁波表现出相同的吸波效果,即吸波特性对入射波的极化方向不敏感。     

用于双酚A检测的电化学传感器电极修饰复合材料的研究进展

双酚A(BPA)广泛用于环氧树脂、聚碳酸酯塑料、阻燃剂、化妆品乃至婴幼儿用品等的生产,但其作为一种内分泌干扰物会导致人体新陈代谢和生殖机能紊乱,严重时还会引发各种癌症.在各类BPA检测技术中,电化学方法因操作简便、响应时间快、灵敏度高、成本低和仪器便携等优势而受到了人们的重视.评述了近5年来用于BPA检测的电化学传感器...     

A Novel Urea Amperometric Biosensor Based on Secretion of Wild Winter Jasmine Petal Cells Modified on Graphite-Epoxy Composite Electrode

A new kind of amperometric biosensor was designed for detection of urea with a high selectivity, sensitivity and wide detection range based on the secretion of whole living cells of wild winter jasmine petals paste covered on a graphite-epoxy composite basic electrode surface. The petal paste from mashed fresh winter jasmine petals was tightly fixed on the basic electrode surface with teflon thin film to keep it contact with electrode surface. During the mashing process, the winter Jasmine petal cells secrete some species, which are electrochemical active and gives an oxidation peak at 0.316 V （vs. SCE） in differential pulse voltammetric curve. The interactions of secreted species with urea molecules, and results in the decrease the oxidation peak current. The oxidation peak current was decreased linearly with the logarithm of urea concentration in the range of 1.3×10^-16-4.57 ×10^-16 M with the detection limit of 1.3×10^-16 M.     

A Poly(amphiphilic pyrrole)-Flavin Reductase Electrode for Amperometric Determination of Flavins

The electropolymerization of a flavin reductase-amphiphilic pyrrole ammonium mixture previously adsorbed on the electrode surface provides the efficient entrapment of the enzyme in a functionalized polypyrrole film. The enzyme film was characterized and applied to the detection of several flavins and pyridine nucleotides. The response of the bioelectrode was based on the amperometric oxidation, at -0.1 V vs SCE, of the enzymically generated dihydroflavins in the presence of reduced pyridine nucleotides. The highest sensitivities and detection limits were 668 mA M(-1) cm(-2) and 4 nM for riboflavin, 179 mA M(-1) cm(-2) and 20 nM for flavin mononucleotide, and 107 mA M(-1) cm(-2) and 40 nM for flavin adenine dinucleotide. Direct electrochemical measurements at -0.65 V and electroenzymatic measurements at -0.1 V of riboflavin, carried out with these bioelectrodes, show that an amplification phenomenon occurs, due to an electrochemical recycling reaction of enzyme substrate. A nonamplified response to reduced pyridine nucleotides was also obtained in the presence of 0.1 mM riboflavin. The sensitivity and detection limit of the bioelectrode are 19.6 mA M(-1) cm(-2) and 0.2 μM for NADH and 11.2 mA M(-1) cm(-2) and 0.5 μM for NADPH.     

金/钯哑铃状纳米晶的制备及其催化对硝基苯酚还原研究

采用晶种-溶液生长法制备了单分散性良好、长径比均一的Au纳米棒, 利用H₂PdCl₄作为前驱体, CTAC作为软模版, 抗坏血酸作为还原剂对Au纳米棒进行改性合成了金/钯哑铃状结构纳米晶(Au/Pd NDs)。采用透射电子显微镜(TEM)、X射线能谱仪(EDS)和紫外-可见分光光度计(UV-Vis-NIR)对样品的结构和形貌进行表征, 探讨了铃铛状结构形成的机理, 并研究了其对硼氢化钠还原对硝基苯酚反应的催化性能。结果表明: 大量的多晶钯颗粒定向选择生长在金纳米棒(AuNRs)两端, 形成哑铃状结构; 通过调控还原剂与前驱体的比例, 铃铛尺寸连续可调。当钯的分散性好且总的催化活性位点多时, 金/钯哑铃状结构纳米晶催化对硝基苯酚还原的效率高。钯颗粒尺寸为20.7 nm的Au/Pd NDs(0.04 mg/mL)催化对硝基苯酚还原的反应速率常数可达0.44 min^-1, 证明其是一种非常有效的催化剂。     

Sulfur-Induced Low Crystallization of Ultrathin Pd Nanosheet Arrays for Sulfur Ion Degradation-Assisted Energy-Efficient H2 Production

The utilization of thermodynamically favorable sulfur oxidation reaction (SOR) as an alternative to sluggish oxygen evolution reaction is a promising technology for low-energy H₂ production while degrading the sulfur source from wastewater. Herein, amorphous/crystalline S-doped Pd nanosheet arrays on nickel foam (a/c S-Pd NSA/NF) is prepared by S-doping crystalline Pd NSA/NF.  Owing to the ultrathin amorphous nanosheet structure and the incorporation of S atoms, the a/c S-Pd NSA/NF provides a large number of active sitesand the optimized electronic structure, while exhibiting outstanding electrocatalytic activity in hydrogen evolution reaction (HER) and SOR. Therefore, the coupling system consisting of SOR-assisted HER can reach a current density of 100 mA cm⁻² at 0.642 V lower than conventional electrolytic water by 1.257 V, greatly reducing energy consumption. In addition, a/c S-Pd NSA/NF can generate H₂ over a long period of time while degrading S²⁻ in water to the value-added sulfur powder, thus further reducing the cost of H₂ production. This work proposes an attractive strategy for the construction of an advanced electrocatalyst for H₂ production and utilization of toxic sulfide wastewater by combining S-doping induced partial amorphization and ultrathin metal nanosheet arrays.     

Formation of rectangularly shaped Pd/Au bimetallic nanorods: evidence for competing growth of the Pd shell between the 110 and 100 side facets of Au nanorods

In this letter, we report the competing growth of a Pd shell on the {110} and {100} facets of Au nanorods (Au NRs). This results in the disappearance of unstable {110} facets and the formation of rectangularly shaped Pd/Au bimetallic nanorods that show only four stable {100} side surfaces. The energy minimization to a more stable morphology is believed to be the driving force for the formation of the rectangular shape of the Pd shell.     

海洋电场探测电极的研究概况

海洋电场探测技术的研究具有广泛的应用领域和重要的军事意义。许多国家在电场探测电极研制和测量系统开发方面的技术已经相当成熟,而我国对于相关领域的研究还处于实验阶段,电极加工工艺和性能参数的研究均落后于西方国家。针对以上情况,系统论述了近20年来国内外关于海洋电场探测电极的研究进展,涉及了电极类型选择、材料的特性、电极性能指标和检测特性等,结合笔者研究分析了海洋电场探测电极的发展趋势和进一步研究的方向。     

Ultrasonic Assisted Fabrication of Nanocomposite Electrode Materials Au/C for Low-Voltage Electronics

Au/C nanocomposites have been obtained by the ultrasonic assisted reduction of HAuCl₄ solutions, impregnated in carbon material pores, using NaBH₄ as a reducing agent. It was established that conditions of nanocomposite (NC) synthesis exert an essential influence on the shape and size characteristics of Au filler and functional properties of NCs. Characterization of NCs by X-ray diffraction, small-angle X-ray scattering, and cyclic voltammetry methods has revealed that an increase in the NaBH₄ concentration raises not only gold nanoparticle dispersion in composites but also an electrochemical capacitance of Au/C NC electrode materials. A higher specific capacitance (700 F/g) for the NC electrode (NC-5 wt%-Au/C-1) was observed at a scanning rate of 10 mV/s in the potential window from (?1)V to (+1)V.