“annulus”的概念、定义、翻译、参考文献-科学参考

annulus

Physics

The plane figure formed between two concentric circles of different radii, R and r. Its area is π‎(R² − r²).

Mathematics

The region between two concentric circles. If the circles have radii r and r + w, the area of the annulus is equal to $π {(r + w)}^{2} - π r^{2}$ , which equals $w \times 2 π (r + \frac{1}{2} w)$ . It is therefore the same as the area of a rectangle of width w and length equal to the circumference of the circle midway in size between the two original circles.

An annulus

Chemical Engineering

The region between two concentric circles. The area of an annulus is equal to $π (d_{1}^{2} - d_{2}^{2}) / 4$ where d₁ and d₂ are the outer and inner radii. An annular gap is the clearance between two concentric pipes or tubes. The use of concentric pipes or tubes is found in the nuclear industry as a form of double containment. The central pipe is used to carry a radioactive liquid such as plutonium nitrate and the gap in the annular gap is kept under reduced pressure. In the event of leaks, the radioactive liquid is retained within the annular gap and recovered without release into the environment.

Biology

1. (in botany)
a. A ragged ring of tissue that remains on the stalk of a mushroom or toadstool. Also called a velum, it is formed from the ruptured membrane that originally covered the lower surface of the cap.
b. The region of the wall of a fern sporangium that is specialized for spore dispersal. It consists of cells that are thickened except on their outer walls. On drying out, the cells contract and the sporangium ruptures, releasing the spores. The annulus springs back into position when the residual water in the cells vaporizes and any remaining spores are dispersed.
2. (in zoology) Any of various ring-shaped structures in animals, such as any of the segments of an earthworm or other annelid.

Geology and Earth Sciences

A ring-like structure used, for example, to describe a discrete ring of ejecta around a martian rampart crater.

单词	annulus
释义	annulus Physics The plane figure formed between two concentric circles of different radii, R and r. Its area is π‎(R² − r²). Mathematics The region between two concentric circles. If the circles have radii r and r + w, the area of the annulus is equal to $π {(r + w)}^{2} - π r^{2}$ , which equals $w \times 2 π (r + \frac{1}{2} w)$ . It is therefore the same as the area of a rectangle of width w and length equal to the circumference of the circle midway in size between the two original circles. An annulus Chemical Engineering The region between two concentric circles. The area of an annulus is equal to $π (d_{1}^{2} - d_{2}^{2}) / 4$ where d₁ and d₂ are the outer and inner radii. An annular gap is the clearance between two concentric pipes or tubes. The use of concentric pipes or tubes is found in the nuclear industry as a form of double containment. The central pipe is used to carry a radioactive liquid such as plutonium nitrate and the gap in the annular gap is kept under reduced pressure. In the event of leaks, the radioactive liquid is retained within the annular gap and recovered without release into the environment. Biology 1. (in botany) a. A ragged ring of tissue that remains on the stalk of a mushroom or toadstool. Also called a velum, it is formed from the ruptured membrane that originally covered the lower surface of the cap. b. The region of the wall of a fern sporangium that is specialized for spore dispersal. It consists of cells that are thickened except on their outer walls. On drying out, the cells contract and the sporangium ruptures, releasing the spores. The annulus springs back into position when the residual water in the cells vaporizes and any remaining spores are dispersed. 2. (in zoology) Any of various ring-shaped structures in animals, such as any of the segments of an earthworm or other annelid. Geology and Earth Sciences A ring-like structure used, for example, to describe a discrete ring of ejecta around a martian rampart crater.
随便看	trench Trenchard, Hugh Montague, 1st Viscount of Wolfeton (1873–1956) trenched piping trench warfare trend trend-cycle decomposition trend surface analysis Trent affair (November–December 1861) Trent, Council of (1545–63) Treptichnus pedum Treschev, Sergei Yevgenyevich (1958– ) Treuhandanstalt trevorite tri- triac triacetone triperoxide triacylglycerol triad Triad Societies trial trial and error trial-and-error learning trial and improvement trial by ordeal trial function