三峡大坝 / Three Gorges Dam

世界第一大的水电工程，位于西陵峡中段的湖北省宜昌市境内的三斗坪，距下游葛洲坝水利枢纽工程38公里。三峡大坝工程包括主体建筑物工程及导流工程两部分，工程总投资为954.6亿元人民币。于1994年12月14日正式动工修建，2006年5月20日全线建成。2010年7月19日，三峡大坝将迎来一次峰值在65000立方米/秒左右的洪水。堪比1998年长江三峡河段的最高峰值，这也将是三峡水库建成以来所面临的规模最大的一次洪水挑战。


@B About the porosity of dams
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Black Body

Black Body Radiations

A black body is an idealized physical body that absorbs all incident electromagnetic radiation. Because of this perfectabsorptivity at all wavelengths, a black body is also the best possible emitter of thermal radiation, which it radiatesincandescently in a characteristic, continuous spectrum that depends on the body's temperature. At Earth-ambient temperatures this emission is in the infrared region of the electromagnetic spectrum and not visible. The object appears black, since it does not reflect or emit any visible light.

Black Body Simulator

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Luminiferous aether

Light Box - Carlo Bernardini

In the late 19th century, luminiferous aether or ether, meaning light-bearing aether, was the term used to describe a medium for the propagation of light. In fact, it was believed that light could propagate in vacuum. The luminiferous aether had to be something extremely porous, because the light propagates in the smallests paces known.

The key difficulty with the aether hypothesis arose from the juxtaposition of the two well-established theories of Newtonian dynamics and Maxwell's electromagnetism.

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Impluvium

The impluvium is the sunken part of the atrium in a Greek or Roman house (domus). Designed to carry away the rainwater coming through the compluvium of the roof, it is usually made of marble and placed about 30 cm below the floor of the atrium.

Inspection (without excavation) of impluvia in Paestum, Pompei and Rome by an American Civil Engineer indicated that the pavement surface in the impluvia were porous or the non-porous stone tiles were separated by a gap significant enough to allow a substantial quantity of water to stand in the basin of the impluvium, filter through the cracks and through layers of gravel and sand into a holding chamber below ground.