| 1. | ρ is the mass density of the material.
为材料的质量密度。 |
| 2. | If the density is smaller , the universe will expand forever
若质量密度比临界值少，宇宙便会无休止地膨胀，我们称之为 |
| 3. | Introducing mass density allows the equation to be simple , understandable and applicable
而且，引入质量密度后，该方程形式简单并易于理解和应用。 |
| 4. | The density of the universe is still unknown . one of the major problems is the existence of
要准确量度宇宙的质量密度非常困难，最大的障碍来自宇宙的 |
| 5. | It takes a very large mass or a great concentration of mass to produce much spacetime curvature
我们得有非常大的质量或者很高的质量密度，才能产生很大的时空曲率。 |
| 6. | The largest scale on which the mass density has been measured with any precision is that of superclusters
已经用任何精密测量的质量密度的最大值是超星系团的数值。 |
| 7. | Mass density is the physical quantity determining the future of the universe . there is a value called the
宇宙的质量密度决定了宇宙的命运，假若质量密度大过某一称为 |
| 8. | In the case of an open universe , the mass density ( denoted by the greek letter omega ) is less than unity , and the universe is predicted to expand forever
在一开放的宇宙里，质量密度(以希腊字母欧米加表示)是小于平均数，且宇宙被预言永远地膨胀下去。 |
| 9. | A parameter known as the " mass density " - that is , how much matter per unit volume is contained in the universe - determines which of the three possibilities applies to the universe
以“质量密度”闻名的一个参数-也就是,在宇宙里含有多少单位体积物质?确定三种可能性哪一种适用于宇宙。 |
| 10. | Considering the randomness of physics parameter ( density and elastic module ) of structural material , structural dynamic characteristic based on probability is analyzed taking plates as example
在考虑结构材料的物理参数（质量密度和弹性模量）为随机变量的情况下，对板结构进行了基于概率的结构动力特性分析。 |
