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1.
In the calibration of the optical trap stiffness, it is found that there appears an attenuating oscillation as an oscillatory disturbance added to the trapped bead movement, when the scanner is driven by a triangular wave input.An equivalent oscillator model is put forward to explain the mechanism of the oscillatory disturbance. Both the measurements and calculations show that the attenuating oscillation comes from the oscillation of the scanner and the triangular wave drive causes this additional oscillation of the scanner. Furthermore, the analysis indicates that the oscillatory disturbance will become stronger, when the stiffness of the trap increases or the natural frequency of the scanner decreases. We adopt another driving way, i.e. a sinusoidal wave input is used instead of the triangular wave input. Our experiment has verified that in this case the oscillatory disturbance is eliminated completely. 相似文献
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用水中周期排列的直径为3μm的单层聚苯乙烯小球以及单个聚苯乙烯小球模拟对光敏感的生物组织,如绿色植物叶肉细胞、动物皮肤的表皮细胞、苍蝇蜜蜂等的复眼以及一种海蛇尾背部的光敏器官的光强分布.通过观测聚苯乙烯小球在不同深度的光强分布,发现随着深度的改变其光强分布是截然不同的.在小球的横截面上,光强分布不很均匀而且呈有规律的花纹图案.在小球的外面,光强分布表现为独立的透镜成像分布.周期排列的小球与单个小球在其横截面上的光强分布也完全不同,前者的光强分布表现出球与球之间很大的相关性.
关键词:
生物组织
周期排列
光强分布 相似文献
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Membrane tethers are extracted from breast cancer cells using a force generated by an optical trap. It is experimentally obtained that the radius of tether is about 0.1μm and the static tether force is about 8.5 pN. Calculations based on the experimental measurements give a bending modulus for the tether of 1.35 x 10^-19 N.m and a surface membrane tension of 6.76 x 10^-6 N/m in the breast cancer cell. The treatment with cytochalasin D results in the decreasing bending modulus and decreasing apparent surface tension. When the membrane protein caveolin is over-expressed, similar cases occur in bending modulus and apparent surface tension. In addition, the viscous resistance coefficient of the membrane is calculated to be 1.15pN.s/μm according to the dynamic tether forces obtained under different pulling velocities. 相似文献
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We propose a mathematical model to analyse the membrane tether formation process on a cell surface with reservoir. Based on the experimental results, the membrane reservoir density of breast cancer cell was obtained, ρ=8.02. The membrane surface viscosity between membrane and environment η is 0.021(pN.s/μm^3), and the static force F0=5.71pN. 相似文献
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高效液相色谱-电化学(库仑电极)阵列检测技术用于植物内源激素等小分子物质的差异显示 总被引:13,自引:0,他引:13
以壳寡糖为诱导物处理烟草植株,利用高效液相色谱-电化学(库仑电极)阵列检测技术检测不同处理时间植物体内内源激素的变化情况及其他小分子物质的差异显示。所用色谱柱为Hypersil BDS C18 柱(4.6 mm i.d.×200 mm, 5 μm),八通道电化学阵列检测器(八个电极)的检测电势依次为-200,300,400,500,600,700,800,850 mV。结果表明,茉莉酸(JA)和赤霉酸(GA)含量在用壳寡糖处理6 h时达到高峰,吲哚乙酸(IAA)含量在处理8 h时达到高峰。处理后烟草植株产 相似文献
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Under illumination of excitation light, the force that can make fluorescent dye-labelled microtubules break up is measured by using dual-beam optical tweezers. It is found that this force is about several piconewtons, which is two orders of magnitude smaller than that without fluorescence label. Microtubules can be elongated about 20% and the increase of the tensile force is nonlinear with the microtubule elongation. Some qualitative explanations are given for the mechanisms about the breakup and elongation of microtubules exposed to excitation light. 相似文献
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Measurements of displacement and trapping force on micron-sized particles in optical tweezers system
A high-stability optical tweezers equipped with a high-precision measurement system of displacement and force is set up. The
results show that this combination can be used to carry out quantitative measurements of small displacements and forces for
micron-sized spheres. The precision of measurements has reached nanometers and piconewtons, respectively. 相似文献
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