To test the idea, the researchers measured the density of sweat pores. Because they knew that touch receptor cells cluster around sweat pores.

为了验证这一想法，研究人员又测量了志愿者指尖的汗毛孔密度，因为他们知道触觉受体细胞总是聚集在汗毛孔周围的。

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Near the core of this cluster, the density of stars is about a hundredtimes greater than the density in the neighborhood of our sun.

在星团的核心区域，恒星的密度是我们太阳系附近的几百倍。

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The surface density of galaxies in a cluster can be measured from photographs.

一个星系团中星系的表面密度可从其照片上测得。

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They endorse rezoning for increased density permitting, in particular, a cluster of five to six buildings, 700 to 900 feet tall (the Chrysler Building is 1, 046 feet), west of Grand Central around Vanderbilt Avenue, with slightly smaller towers marching up Park.

WSJ: Not Visionary Enough | By Julie V. Iovine