选择交流电作为工业标准的原因很简单，在早期供电距离很短的电网里，交流电的损耗比直流电小。

The reason was that over the short distances spanned by early power grids, AC transmission suffers lower losses than DC. It thus became the industry standard.

youdao

由此导出变压器年运行费率、最低年运行费率、变压器最佳负载率以及变压器经济运行区宽和变压器损耗比的关系。

Then, relationships between the quantities mentioned above, the interval of economic operation and the loss factor of transformers are derived and discussed.

youdao

对于摄影两个都不是最佳选择，因JPG比无损耗png小得多，也只是最低程序损失一点画质。

Neither are optimal options for photography, as JPG is much smaller than lossless PNG with only minimal loss of quality.

youdao