共查询到18条相似文献,搜索用时 203 毫秒
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最近固液界面存在纳米气泡已经引起人们越来越多的关注。虽然经典热力学理论认为室温下水中纳米气泡不能稳定存在 ,但近几年越来越多的研究结果却表明固液界面存在纳米气泡 ,并引起疏水长程作用力。目前直接探测固液界面纳米气泡的最有力手段是原子力显微镜 (AFM)技术 ,尤其是AFM的轻敲模式非常适合于柔软样品的研究 ,因此是目前探测固液界面纳米气泡的最有力手段。本文利用轻敲模式对醇水替换方式产生的纳米气泡进行成像 ,籍以研究液体温度对纳米气泡形成的影响。在研究中发现 ,液体的温度对纳米气泡的形成有显著的影响。当液体温度升高… 相似文献
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固/液界面纳米气泡的存在已经得到证实,并成为界面科学研究的一个焦点.在原子力显微镜液体池内制备纳米气泡的基础上,本研究建立了在开放体系中进行醇水替换,制备纳米气泡的方法.原子力显微镜观察显示.开放体系中进行醇水替换,也可以在水/云母界面上稳定地生成纳米气泡.将不同环境下制备的纳米气泡进行比较,统计结果显示,在开放体系下制备的纳米气泡密度较低,形态也较小.不同环境下醇水替换产生的纳米气泡数量和形态的差异,为纳米气泡形成的机制提供了新的佐证.开放体系下纳米气泡制备方法的建立拓展了纳米气泡的制备条件,揭示了纳米气泡存在的普遍性,同时也为纳米气泡性质研究提供了新的途径. 相似文献
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原子力显微镜在液相条件下的成像分析 总被引:1,自引:0,他引:1
本研究利用原子力显微镜(atomic force microscope,AFM)分别对Al2O3纳米模板、云母片及数字光盘在固相及液相务件下进行形貌扫描和云母片上的力 - 距离曲线测量.实验结果分析表明液相条件可以降低针尖的展宽效应,使得形貌成像更能够显示出物体的细微结构.在液相条件下,由于样品表面消除了静电效应和液体的阻滞力结果,力 - 距离曲线显示了较好的力均一性.这些结果为AFM实验技术研究生理条件下的生物样品的形态学及生物分子之间的相互作用力提供了实验可行性. 相似文献
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水中气泡界面的光强研究 总被引:2,自引:0,他引:2
通过菲涅耳公式,对气泡内外界面的光强进行了计算,得出气泡界面第2次反射光强I′2s和I′2p(内表面)、折射光强I2s和I2p(外表面)的一般规律,及不同偏振态的光线在界面第n次反射和折射后的光强与第2次光强的关系。理论和实验均表明,光在气泡界面连续反射4次后基本消失。最后通过激光和CCD相机抓拍到水中气泡的图像,能明显获得出射光线轨迹,实验测量出射光强的值与理论计算值相吻合。 相似文献
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本文选用不同基底和溶剂进行单壁碳纳米管(SWNTs)样品制备,采用原子力显微镜(atomic force microscope,AFM)观察进行表征和观测。结果表明,溶剂和基底对样品制备十分重要,会直接影响AFM观测效果。以去离子水为溶剂进行样品分散时,SWNTs在石英、硅片和云母三种基底上都出现了不同程度的聚积和重叠,影响观测效果。而采用乙醇为溶剂,在石英或云母为基底进行成像时,均可获得质量良好的图像。选择云母作为基底,可以大大减少基底处理时间,制样方便快速,并且能够获得理想的观测效果。 相似文献
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“Liquid marbles” are liquid‐in‐gas dispersed systems stabilized by hydrophobic solid particles adsorbed at the gas‐liquid interface. The structure, stability and movement of these liquid marbles can be controlled by external stimuli such as pH, temperature, light, magnetic and electric fields, ultrasonic, mechanical stress and organic solvents. Stimuli‐responsive modes can be categorized into five classes: (i) liquid marbles whose stability can be controlled by adsorption/desorption of solid particles to/from liquid surfaces, (ii) liquid marbles that can open and close their particle‐coated surface by moving particles to and from the gas‐liquid surface, (iii) liquid marbles that can move, (iv) liquid marbles that can change their shape and (v) liquid marbles that can be split. As a result of these stimuli‐responsive characteristics, liquid marbles offer potential in the areas of controlled encapsulation, delivery and release. 相似文献
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原子力显微镜磁驱动轻敲模式在活细胞成像中的应用研究 总被引:1,自引:0,他引:1
应用MI公司最新发展的磁驱动轻敲模式(MAC mode)时体外培养成纤维细胞系3T3细胞进行在位成像研究.分别用力常数为0.95 N/m及0.03 N/m的微悬臂进行磁驱动轻敲模式成像,并与接触模式进行比较.同时研究了固定细胞与活体细胞之间的形貌差异.结果显示,利用上述两种微悬臂探针,磁驱动轻敲模式均可获得高分辨像.与接触模式相比,磁驱动轻敲模式对活细胞的影响较小,在细胞膜表面微结构及细胞内亚结构成像方面,有明显优势.而接触模式由于其施力方式,使活细胞应力纤维应激性绷紧,更适合于对活体细胞应力纤维的成像研究.固定细胞与活细胞表面形貌存在较大差异,在生理环境下,进行活细胞检测更能了解细胞的真实状况. 相似文献
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A.R. GodfreyAlig M. Akbulut Y. Golan J. Israelachvili 《Advanced functional materials》2006,16(16):2127-2134
The forces between mica surfaces confining solutions of spherical and rod‐shaped ZnS nanoparticles (diameter ca. 5 nm) coated with hexadecylamine or octadecylamine surfactant in dodecane have been measured in the absence and after the introduction of trace amounts of water. Initially, or at very low water content, the water molecules cause the nanoparticles to aggregate and adsorb on the hydrophilic mica surfaces, resulting in a long‐range exponentially decaying repulsive force between the surfaces. After longer times (> 20 h), water bridges nucleate and grow between the nanoparticles and mica surfaces, and attractive capillary forces then cause a long‐range attraction and a strong (short‐range) adhesion. It is found, as has previously been observed in nonaqueous bulk colloidal systems, that even trace amounts of water have a profound effect on the interactions and structure of nanoparticle assemblies in thin films, which in turn affect their physical properties. These effects should be considered in the design of thin‐film processing methodologies. 相似文献
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Seung Goo Lee Ho Sun Lim Dong Yun Lee Donghoon Kwak Kilwon Cho 《Advanced functional materials》2013,23(5):547-553
Rice leaves can directionally shed water droplets along the longitudinal direction of the leaf. Inspired by the hierarchical structures of rice leaf surfaces, synthetic rice leaf‐like wavy surfaces are fabricated that display a tunable anisotropic wettability by using electrostatic layer‐by‐layer assembly on anisotropic microwrinkled substrates. The nanoscale roughness of the rice leaf‐like surfaces is controlled to yield tunable anisotropic wettability and hydrophobic properties that transitioned between the anisotropic/pinned, anisotropic/rollable, and isotropic/rollable water droplet behavior states. These remarkable changes result from discontinuities in the three‐phase (solid–liquid–gas) contact line due to the presence of air trapped beneath the liquid, which is controlled by the surface roughness of the hierarchical nanostructures. The mechanism underlying the directional water‐rolling properties of the rice leaf‐like surfaces provides insight into the development of a range of innovative applications that require control over directional flow. 相似文献