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121.
Wuxiang Zhang Jianzhong Zheng Jiangu Shi Zhongqiu Lin Qitong Huang Hanqiang Zhang Chan Wei Jianhua Chen Shirong Hu Aiyou Hao 《Analytica chimica acta》2015
Nafion covered core–shell structured Fe3O4@graphene nanospheres (GNs) modified glassy carbon electrode (GCE) was successfully prepared and used for selective detection dopamine. Firstly, the characterizations of hydro-thermal synthesized Fe3O4@GNs were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. Then Fe3O4@GNs/Nafion modified electrode exhibited excellent electrocatalytic activity toward the oxidations of dopamine (DA). The interference test showed that the coexisted ascorbic acid (AA) and uric acid (UA) had no electrochemical interference toward DA. Under the optimum conditions, the broad linear relationship was obtained in the experimental concentration from 0.020 μM to 130.0 μM with the detection limit (S/N = 3) of 0.007 μM. Furthermore, the core–shell structured Fe3O4@GNs/Nafion/GCE was applied to the determination of DA in real samples and satisfactory results were got, which could provide a promising platform to develop excellent biosensor for detecting DA. 相似文献
122.
Shu-Zhen LIU Zhi-Qing ZHANG Fang WANG Ting ZHOU Xiu-Feng WANG Gou-Dong ZHANG Ting-Ting LIU Hong-Zhi ZHANG 《物理化学学报》2017,33(10):2052-2057
滚环扩增(RCA)反应作为一种简单高效的等温酶促反应,现已发展为核酸扩增领域的新技术,其产物在组装体搭建和多功能材料的制备方面有着广泛的应用。本文采用琼脂糖凝胶、紫外和透射电镜(TEM)等手段,探究了时间、三磷酸脱氧核糖核苷(dNTPs)、酶以及引物的浓度等因素对脱氧核糖核酸(DNA)滚环扩增产物的影响。结果表明:在反应开始的前30 min,RCA产物的长度受时间的影响比较明显;随着dNTPs浓度的提高,RCA产物的链长增长,浓度也不断提高;酶和引物的浓度对滚环扩增产物的长度没有明显影响,但对RCA产物浓度的影响较大,过量的酶致使RCA产物的含量显著下降。 相似文献
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Magnetic functionalization of living cells has intensively been investigated with the aim of various bioapplications such as selective separation, targeting, and localization of the cells by using an external magnetic field. However, the magnetism has not been introduced to individual living cells through the in situ chemical reactions because of harsh conditions required for synthesis of magnetic materials. In this work, magnetic iron oxide was formed on the surface of living cells by optimizing reactions conditions to be mild sufficiently enough to sustain cell viability. Specifically, the reactive LbL strategy led to formation of magnetically responsive yeast cells with iron oxide shells. This facile and direct post-magnetization method would be a useful tool for remote manipulation of living cells with magnetic interactions, which is an important technique for the integration of cell-based circuits and the isolation of cell in microfluidic devices. 相似文献
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In this paper, we study the stationary problem for the Lotka–Volterra competition system with cross-diffusion in a spatially heterogeneous environment. Although some sufficient conditions for the existence of positive solutions are obtained by using global bifurcation theory, the information for their structure is far from complete. In order to get better understanding of the competition system with cross-diffusion, we focus on the asymptotic behaviour of positive solutions and derive two shadow systems as the cross-diffusion coefficient tends to infinity, moreover, the structure of positive solutions of the limiting system is analysed. The result of asymptotic behaviour also reveals different phenomena from that studied in Wang and Li (2013). 相似文献
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QUALITATIVE ANALYSIS OF DYNAMICAL BEHAVIOR FOR AN IMPERFECT INCOMPRESSIBLE NEO-HOOKEAN SPHERICAL SHELL 总被引:1,自引:0,他引:1
YUAN Xue-gang 《应用数学和力学(英文版)》2005,26(8):973-981
IntroductionIn applications, it is commonly considered that the phenomena of cavity formation,growth and run-through of adjacent cavities occur in materials as precursors to failure. Thesephenomena are mainly due to instability of materials. On the other … 相似文献
129.
In a vertically oscillating circular cylindrical container, singular perturbation theory of two-time scale expansions is developed in weakly viscous fluids to investigate the motion of single free surface standing wave by linearizing the Navier-Stokes equation. The fluid field is divided into an outer potential flow region and an inner boundary layer region. The solutions of both two regions are obtained and a linear amplitude equation incorporating damping term and external excitation is derived. The condition to appear stable surface wave is obtained and the critical curve is determined. In addition, an analytical expression of damping coefficient is determined. Finally, the dispersion relation, which has been derived from the inviscid fluid approximation, is modified by adding linear damping. It is found that the modified results are reasonably closer to experimental results than former theory. Result shows that when forcing frequency is low, the viscosity of the fluid is prominent for the mode selection. However, when forcing frequency is high, the surface tension of the fluid is prominent. 相似文献
130.
构建了具有“Al/DNA-CTMAB/Ag NPs/DNA-CTMAB/ITO”结构的有机忆阻器件, 并对其电流-电压 (I-V)曲线进行测量. 结果表明, 嵌入Ag纳米颗粒层, 不仅可以增强器件的导电性, 而且忆阻特性也显著提高. 当颗粒粒径在15–20 nm范围时, 开-关电流比ION/IOFF能够达到103. 器件的I-V特性受扫描电压幅值VA的影响, 随着VA的增大, 高阻态的电流变化较小, 而低阻态的电流明显增大, 开(或关)电压VSET (VRESET)和ION/IOFF增加. 实验还发现, 器件高低阻状态的相互转换取决于外加电场的方向, 说明该忆阻器具有极性. 相似文献