Secrets of successful stone-skipping

stone-skipping

从理论上分析了打水漂的技巧。

When larger drops evaporate faster

从Kelvin方程中:

$$ p(r_1, r_2) = P - \frac{\gamma \rho_{vapor}}{\rho_{liquid} - \rho_{vapor}}(\frac{1}{r_1} + \frac{1}{r_2}) $$

我们可以推断出,当压力高于该液体的饱和蒸汽压时,小液滴将蒸发并转移到大液滴中,当压力小于饱和蒸汽压时,小液滴会蒸发的比大液滴更快。

但 Leizerson 等人发现,在特殊处理过的云母表面,较小的水滴比较大的水滴蒸发得更慢。

Light from sonication of crystal slurries

简要讨论了超声下摩擦发光(triboluminescence,也称为机械发光 mechanoluminescent)的现象。

Some crystalline materials emit light when they are crushed, rubbed, or scratched; the phenomenon, triboluminescence, is thought to arise from the recombination of charges produced by the breaking of chemical bonds under mechanical stress and is usually associated with asymmetric crystal structures.

— Intriguing aspects of lanthanide luminescence1

生活中也存在类似的现象,比如说碾碎蔗糖块时,可以用肉眼观察到糖块表面会发出闪光。撕胶带的时候,会产生微弱的X射线

Apparatus for studying high-energy emission from peeling tape.

液滴与微通道间的摩擦能否发生类似的荧光?利用芯片的自发光检测液滴,就像一个灯泡一样。

粗略查了一下,有研究在 3D 打印件中掺杂了发光原料,风一吹就会发出绿光:

Fully 2D and 3D printed anisotropic mechanoluminescent objects and their application for energy harvesting in the dark

— Shlomo Magdassi, published in Materials Horizons (IF: 15.717)

What is the best way to lace your shoes?

鞋带的最佳系法。

shoelace

Finer features for functional microdevices

了解过3D打印的人肯定都看过这个简讯,孙洪波教授在双光子领域的开创性工作——纳米牛。

Microfabrication and nanofabrication at subdiffraction-limit resolution.

Tall men have more reproductive success

Here we demonstrate that taller men are reproductively more successful than shorter men, indicating that there is active selection for stature in male partners by women.

没对象的原因找到了

The colourful world of the mantis shrimp

螳螂虾的四色视觉,这个在很多科普文里都能看到,出处原来在这里。

Wood used by Stradivari and Guarneri

三百年前 Stradivari 和 Guarneri 制作的小提琴非常非常出名。查了一下资料,2013 年,一把名为 Vieuxtemps Guarneri 的琴甚至于拍出 1600 万美元的天价。

研究者通过 NMR 和 FTIR 发现,Stradivari 和 Guarneri 在制作小提琴时,对木材进行了一定的化学处理。

Spectroscopy of maple wood samples from antique violins.


  1. The above note is excerpted from Jean-Claude G. Bünzli’s Intriguing aspects of lanthanide luminescence↩︎