Ascertaining that a star has exactly the sun's age is impossible, he says, and many unrelated stars share its chemical composition.
他继续补充道，找到一个和太阳有相同年龄的恒星根本没有可能，而且很多和太阳没有关系的恒星也有着与其相同的化学构成。
Professor Jane Evans, who traces the birthplace of Bronze Age skeletons using a chemical analysis of teeth, believes the visitors were travelling to Britain specifically to see Stonehenge.
简·埃文斯（Jane Evans）教授通过化学手段对牙齿进行分析，确定了男孩的出生地，她相信这个孩子来到英国，就是为了一睹巨石阵的真容。
To get the age estimates, Nielsen and his team used a complex system that combines chemical tests, mathematical models and growth measurements.
为了估算年龄，尼尔森及其小组采用了一种结合化学试验、数学模型和生长测量的复杂系统。
Chemical products of this age are of high technicality and of high additional value.
知识经济时代的化工产品，是技术含量高、附加价值高的产品。
But even the mosquito has been subdued by attention to drain age and by chemical sprays.
但甚至蚊子也由于我们注意排水和化学喷雾而已被抑制住了。
With the curing age increasing, chemical binding capability of these three cements is weakening, but the physical binding capability is increasing.
随着龄期的增加，三种水泥的化学结合能力都减弱，而物理吸附能力都增强。
Ascertaining that a star has exactly the sun's age is impossible he says and many unrelated stars share its chemical composition.
他说，确定一颗恒星恰好跟太阳的年龄相同是不可能的，而很多本不相关的恒星跟太阳的化学成分又是相同的。
The main methods of age estimation at present mostly rely on characteristic physical and chemical changes of skeleton, soft tissue, cells, biomacromolecules and the other substances.
推断年龄目前主要依据人体骨骼、软组织、细胞和生物大分子，以及组织中各类物质的物理和化学特性等随年龄增长的时序性变化。
Objective: To determine the appropriate collecting-time of pummelo peel by comparison and analysis on the chemical compounds in pummelo peel in different fruit-age.
前言：目的：通过对不同果龄的化橘红化学成分比较分析，确定化橘红的适宜采收期。
Chemical fossils (e. g. alkanes and porphyrins) are often the only evidence for life in rocks of PRECAMBRIAN age.
化学化石(烷烃和卟啉)是前寒武纪地层中生命存在的唯一证据。
Edison set up a chemical lab of his own at the age of 10.
爱迪生10岁时建立了自己的实验室。
At the same time, the relationship between the physical-chemical properties of the harden paste and the hydration age, the pozzolan activity of the fly ash in the harden paste have been discussed.
同时讨论了粉煤灰水泥硬化浆体的物理化学性能与水化时间的关系，以及硬化浆体中粉煤灰的火山灰活性。
At the same time, the relationship between the physical-chemical properties of the harden paste and the hydration age, the pozzolan activity of the fly ash in the harden paste have been discussed.
同时讨论了粉煤灰水泥硬化浆体的物理化学性能与水化时间的关系，以及硬化浆体中粉煤灰的火山灰活性。
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