You can therefore evolve a spec with new elements and constraints without impacting or forcing a migrationof product data.
因此，您可以使用新的元素和约束来使spec发生演变，而不会对产品数据产生影响或实施迁移。
2
The migration mechanism ofelements in stream sediments is the theoretics part of regional geochemical surveys.
水系沉积物元素迁移机理是区域化探方法的理论基础。
3
On the other hand, the population migration affects the spatial structure of intraregional economic, social and other elements and changes in industrial distribution.