影响隔热油管技术寿命的主要因素是气害，特别是氢害。
The main factor influencing the technical life of the tubing is the gas harm, particularly the hydrogen harm.
以个人计算机为例来研究技术寿命周期较短设备的更新决策。
Finally, this paper discusses the maintenance and replacement decision of facility of short life and chooses personal computers as a example.
以解放牌汽车为例做了实际计算，结果经济寿命只有技术寿命的50%左右。
Then a concrete example is calculated. The economical life of certain truck is only about 500% of its technical life.
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