为保证川东北地区罗家寨、铁山坡构造高含硫气井长期采气高抗硫要求，2003年起，从国外进口了部份套管头和采气井口。

In order to ensure the requirement of high anti-sulfur in Luojiazhai and Tieshan sour gas well, some casing heads and gas-producing wellheads have been imported since 2003.

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我们取材进口天然桦木榉木原木，不使用科技复合技术木板及化工合成塑料板材，木架使用打榫插接构造，尽量减少或不使用胶粘剂。

Instead of using composite and chemical synthesis technology, we import birch and beech from overseas and adopt Tenon plug structure to avoid or reduce the use of cementing compound.

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通过对进口阔叶木材取样与切片观测，对22种进口阔叶材的木材构造与识别特征进行了具体描述。

It has specifically described 22 kinds of import broad-leaved timber structure and identification characteristic through sampling and cut-section observation of import broad-leaved timber.

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