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《生命科学仪器》2017,(4)
目的研究叶酸偶联的PFBT荧光聚合物纳米探针对U87细胞、H1299细胞及SKOV3细胞的细胞靶向效果。方法采用纳米共沉淀法制备PFBT聚合物纳米探针,采用EDC偶联试剂制备叶酸修饰的聚合物纳米探针,用共聚焦显微镜观察纳米探针在U87细胞、H1299细胞及SKOV3细胞的成像效果。结果 PFBT聚合物纳米探针与U87细胞、H1299细胞及SKOV3细胞共孵育12 h后,在细胞内仅检测到微弱的探针的荧光;而偶联叶酸后在相同条件下使细胞内的探针的荧光强度增加。结论叶酸偶联的PFBT聚合物纳米探针对U87细胞、H1299细胞及SKOV3细胞具有一定的靶向效果。 相似文献
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设计了一种用热拉伸法制备毛细管微探针的新装置,可制作尖端内外径从亚微米量级至数十微米量级的毛细管微探针。介绍了微探针在细胞人工授精操作中的应用实例,并提出一种基于扫描隧道显微术与电化学技术,利用微探针进行集成电路微细加工的新方法。 相似文献
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UV-LIGA技术制备微型柔性镍接触探针 总被引:1,自引:0,他引:1
对探针的制作方法、关键工艺环节等进行了分析与研究,给出了基于UV-LIGA技术制备微型柔性镍接触探针的工艺过程,分析了制备的技术关键,试验优选了关键制备环节的工艺参数,在此基础上,制作出微型柔性镍接触探针。试验结果表明:采用工艺条件优选的UV-LIGA技术,如前烘60 ℃,120 min,90 ℃,120 min;较大曝光剂量;后烘65 ℃,10 min,95 ℃,45 min;匀胶后静置、随炉冷却和超声辅助显影等辅助措施,所制备出的柔性接触探针(主体总长4 mm,宽80 μm,高100 μm;弹簧处高宽比为5(100 μm:20 μm))尺寸精度高;三角锥状针尖曲率半径小于5 μm;缺陷少,形貌质量高。 相似文献
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本文提出一种面向脉动微压传感的多光束干涉光纤法布里-珀罗(FP)探针。建立探针多光束干涉波长漂移与微压传感模型,分析其在气、液相环境中微压灵敏度差异。采用化学腐蚀、放电熔接、精密切割技术制备光纤探针器件。利用医用注射器、透明柔性软管、石英插芯构建微压测试环境,通过有限元仿真分析测试环境内部压强分布情况,在气相环境压强范围14.41~85.22 kPa、液相环境压强范围4.50~26.02 kPa的测试条件下,对3支光纤探针微压传感特性进行分析。实验结果表明,气、液相环境中,探针波长均随压强增大发生红移现象,反之,发生蓝移现象;气相环境探针平均微压灵敏度可达8.210 pm·kPa-1,液相环境探针平均微压灵敏度可达66.720 pm·kPa-1,高于气相环境,与理论模型相符。选取气、液相环境中微压灵敏度最高的光纤探针进行液相脉动微压传感特性研究。实验结果表明,5个脉动周期内探针波长响应良好,且重复性误差较小。本文提出的光纤探针结构紧凑,易于制备,灵敏度高,可实现1 Hz频率范围内的脉动微压传感,为液相环境脉动微压传感提供了重要的参考价值。 相似文献
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溶胶-凝胶固定纳米光纤探针上生物活性分子的研究 总被引:2,自引:1,他引:1
为提高纳米光纤生物传感器的性能,研究了以溶胶-凝胶法将生物活性分子固定于纳米光纤探针上。首先以正硅酸乙酯(TEOS)为前驱体,制备了以葡萄糖氧化酶(GOD)为生物活性分子的溶胶,然后利用提拉法将GOD凝胶固定于纳米光纤探针上;讨论了固定化GOD活性及凝胶膜在纳米光纤探针上成膜的条件;最后通过扫描电子显微镜检测到薄膜均匀连续,生物探针尺寸小于1μm,并利用电子探针验证了GOD被固定于纳米光纤探针上。 相似文献
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Machleidt T Franke KH Romanus H Cimalla V Niebelschütz M Spiess L Ambacher O 《Ultramicroscopy》2007,107(10-11):1086-1090
Knowledge of tip geometry is necessary for reproducible atomic force microscope (AFM) measurements. This is particularly important for measurements in contact mode, in which a certain wear of the tip will always occur. For small or flat structures or for structures of larger dimensions, knowledge of the tip radius and the entire tip geometry is important. Additionally, the tilt of the tip in relation to the sample is of importance. Normally, very complicated lithographically manufactured structures for tip characterization are used. In contrast, the structures shown in this work are very simple. For measuring the tip geometry very thin foils patterned by focused ion beam (FIB) were used. In this work we demonstrate the possibility of determining the AFM tip geometry and the tilt based on several different large structures. A proven algorithm was developed for the reconstruction of the tips. The shape of FIB-structured foils was determined by electron microscopy prior to AFM measurements. This new method for determining tip shape is also presented as it compares to other current methods. In this case a discussion on the stability and advantages of the new method is presented. 相似文献
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用有限元方法计算X光源场发射阴极电流 总被引:1,自引:0,他引:1
针对场致发射阵列建立了有效的三维有限元模型来分析单个尖锥的发射电流.考虑到场致发射阵列的周期性和尖锥的轴对称性,仅对一个尖锥单元的1/4进行分析.对模型的表面施加电压边界条件,计算得到尖锥表面电场强度分布,电场强度在尖锥顶点最强,场发射电流在此处也最强.由Fowler-Nordheim函数可得到尖锥表面的场致发射电流密度分布,对整个尖锥表面进行积分后得到了单个尖锥的场致发射电流约为7μA.计算了在100V门电压下不同顶端半径的场致发射电流.结果显示,场发射对顶端半径有很强的依赖性.计算了100个顶端半径为8nm的尖锥在不同门电压下的总场致发射电流,发射电流与开启电压与实际测量值符合得很好. 相似文献
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A field ion microscope was used to examine the stability of the atomic arrangement at tip apexes. Although a single W atom at the top layer of a [111]-orientated tip apex protrudes from the underneath layer by only 0·91 Å, the present study suggests that the (111)-orientated W tip is the most desirable tip for scanning tunnelling microscopes because a large activation energy for surface diffusion on the (111) plane immobilizes the apex atom while the tip scans over a specimen surface and the tip apex can be resharpened by simply heating the tip. 相似文献
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Joo Hoon Choi Chad Steven Korach 《International Journal of Precision Engineering and Manufacturing》2011,12(2):345-354
Depth-sensing indentation measurements of surfaces and structures with indentation depths less than 100 nm necessitate the
use of accurate area functions for correct property evaluation. Here, the effect of a blunt nanoindenter tip geometry is characterized
using atomic force microscopy to measure the direct tip geometry and modeled by a power law profile shape. Direct measurement
of tip geometry is a method to observe changes in the tip curvature and transition from the blunt tip region to an ideal tip
geometry. The tip shape, curvature, and transition to ideal geometry is found to correspond with the increase in hardness
observed experimentally in SiO2 using a self-similar contact model. For a Berkovich indenter, tip bluntness was found to have
a power law degree of 1.5 near the tip apex with a continuously varying degree of bluntness until an ideal pyramidal shape
was reached at a depth of 160 nm. 相似文献
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Characteristics of fracture during the approach process and wear mechanism of a silicon AFM tip 总被引:1,自引:0,他引:1
The wear of an atomic force microscope (AFM) tip is one of the crucial issues in AFM as well as in other probe-based applications. In this work, wear tests under extremely low normal load using an AFM were conducted. Also, in order to understand the nature of silicon tip wear, the wear characteristics of crystal silicon and amorphous silicon oxide layer were investigated by a high-resolution transmission electron microscope (HRTEM). It was found that fracture of the tip readily occurred due to impact during the approach process. Experimental results showed that the impact should be below 0.1 nNs to avoid significant fracture of the tip. Also, it was observed that wear of the amorphous layer, formed at the end of the tip, occurred at the initial stage of the silicon tip damage process. Based on Archard's wear law, the wear coefficient of the amorphous layer was in the range of 0.009-0.014. As for the wear characteristics of the silicon tip, it was shown that wear occurred gradually under light normal load and the wear rate decreased with increase in the sliding distance. As for the wear mechanism of the silicon tip, oxidation wear was identified to be the most significant. It was shown that the degree of oxidation was higher under high normal load and in a nitrogen environment, oxidation of the silicon tip was reduced. 相似文献
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围绕V形切口尖端裂纹起裂方向,分析了V形切口尖端裂纹应力场、位移场、应力强度因子,提出了裂纹起裂方向的主应力判别准则。首先,详细给出了V形切口尖端应力应变场的求解方法,通过裂纹尖端场本征值的三次线性拟合及误差分析,确定了V形切口尖端裂纹位移场;然后,建立了V形切口尖端的数值分析模型,运用数值计算方法确定了应力强度因子和切口强度因子,提出了V形切口尖端裂纹起裂方向的主应力判断准则,给出了外推法求解分析过程;最后,以LY8为试验材料,在张角2β=60°的V形切口情况下,对提出的V形切口尖端裂纹起裂方向计算方法与判别准则进行了试验验证。 相似文献
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The shape of an atomic force microscope (AFM) silicon tip has a significant effect on the mechanical modification of the polymer surface, especially for a longer sliding distance of from several to several hundreds of millimeters. In this work, a pyramidal silicon tip was used to cut into the polymethyl methacrylate (PMMA) surface, forming nanogrooves with a linear sliding distance of about 80 mm and wear box structures with a total tip sliding distance of 1,024 mm. The effects of the tip edges and the tip radius on the form of the wear debris chips, wear depth, and debris transferred to the tip were investigated. The experimental results showed that four sides of the tip influenced the morphology of the removed material. Adhesion appeared to play a role in the tip wear mechanism by successive removal of SiO2 layers during transfer of adhered PMMA from the tip to the surface. The tip radius generally increased with sliding distance. Simultaneously, adhesion of the removed materials to the tip induced a larger tip radius and a sharper tip was revealed as dropping off of the materials during the test from time to time. Thus, with the same normal load the worn tip may induce failure of the machining process. The results presented in this study provide insight into long-term nanoscratch/wear and nanomechanical machining of glassy polymer surfaces with a silicon AFM tip. 相似文献
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本文利用断裂力学知识和张量分析方法得到了外加应力在裂尖滑移系沿滑方向的分解剪切应力,并定义了裂纹尖端Schmid因子。本文还讨论了裂尖应力场对裂尖滑移系开动的影响。当裂纹尖端向外发射位错时,裂尖滑移系的选择由裂尖Schmid因子支配,并且在裂尖附近区域内位错源开动或螺位错交滑移时滑移系的选择也由裂尖Schmid因子支配。 相似文献
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This article demonstrated a new approach for fabrication and sharpening of metal tips of scanning probe microscopes. Experimentally, a metal tip was heated and melted by a focused laser light. The tip was then sharpened by a strong electric field and consolidated as the laser was turned off. With a low‐vacuum and a high‐voltage source, a 25‐µm indium‐coated platinum wire was sharpened to a tip with diameters below 50 nm. The minimal tip radius by this method is estimated to be below 1 nm. With this technique, in situ tip sharpening for SPM would be possible. SCANNING 34: 76–79, 2012. © 2011 Wiley Periodicals, Inc. 相似文献