概括
科学家们现在可以使用激光悬浮和控制带电和中性液滴. 这种技术对于推进云物理,气溶科学和流体动力学研究至关重要.
科学领域:
- 物理 物理学 物理
- 化学 化学 化学
- 环境科学 环境科学
背景情况:
- 悬浮和操纵液滴对于研究各种物理和化学现象至关重要.
- 以前的方法在粒子大小,激光功率和陷深度方面存在局限性.
研究的目的:
- 开发和完善基于激光的技术,用于稳定的悬浮和液滴的操纵.
- 将这些技术扩展到更小的粒子,更低的激光功率和更深的陷.
主要方法:
- 使用激光束稳定悬浮充电和中性液滴.
- 扩展该技术,以低激光功率 (<1mW) 操纵小到1微米的粒子.
- 实现更深的光学陷,能够承受比粒子重量大十倍的力.
主要成果:
- 证明了稳定的悬浮和液滴操纵在1-40微米直径范围内.
- 成功地将该技术应用于微微粒子,并降低了激光功率.
- 开发了更深的陷,显著提高了控制悬浮粒子的能力.
结论:
- 精致的激光悬浮技术为液滴提供了前所未有的控制.
- 这一进步对云物理,气溶科学,流体动力学和光学有重大影响.
- 允许高精度观察与光,电场,气体和其他水滴的滴相互作用.
相关概念视频
01:18Rise of Liquid in a Capillary Tube
When very thin cylindrical tubes, called capillaries, are dipped in a liquid, the liquid rises or falls in the tube compared to the surrounding liquid. This phenomenon is called capillary action. Capillary action occurs due to the combination of two opposing forces: the cohesive forces of the liquid, which cause it to stick to itself and form a rounded shape, and the adhesive forces between the liquid and the walls of the container, which cause the liquid to be attracted to the container walls.
01:13Excess Pressure Inside a Drop and a Bubble
The shape of a small drop of liquid can be considered spherical, neglecting the effect of gravity. This drop can further be considered as two equal hemispherical drops put together due to surface tension. The forces acting on the spherical drop are due to the pressure of the liquid inside the drop, the pressure due to air outside the drop, and the force due to the surface tension acting on the two hemispherical drops.
01:17Accelerating Fluids
When a fluid is in constant acceleration, the pressure and buoyant force equations are modified. Suppose a beaker is placed in an elevator accelerating upward with a constant acceleration, a. In the beaker, assume there is a thin cylinder of height h with an infinitesimal cross-sectional area, ΔS.
The motion of the liquid within this infinitesimal cylinder is considered to obtain the pressure difference. Three vertical forces act on this liquid:
The motion of the liquid within this infinitesimal cylinder is considered to obtain the pressure difference. Three vertical forces act on this liquid:
01:22Surface Tension of Fluid
Surface tension is a fundamental property of fluids, occurring at the boundary between a liquid and a gas or between two immiscible liquids. This phenomenon arises from the cohesive forces between molecules at the fluid's surface, creating an effect similar to a stretched elastic membrane. Inside each fluid, molecules are equally attracted in all directions by neighboring molecules, but surface molecules experience a net inward force, resulting in surface tension.
Surface tension varies with...
Surface tension varies with...
01:20Momentum And Radiation Pressure
An object absorbing an electromagnetic wave would experience a force in the direction of propagation of the wave. This force occurs because electromagnetic waves contain and transport momentum. The force accounts for the wave's radiation pressure exerted on the object. Maxwell's prediction was confirmed in 1903 by Nichols and Hull by precisely measuring radiation pressures with a torsion balance. The measuring instrument had mirrors suspended from a fiber kept inside a glass container. Nichols...