two-by-four

First, we can obtain boom amplitude angle and tower crane basement angle of two cranes by means of absolute encoder. Then, we use projection method for establishment of two-dimensional projection model of crane, and so as to analysis four-quadrant double-arm anti-collision problem.

通过绝对编码器我们可以获得两台起重机的臂架幅度角与塔基旋转角度，然后，运用投影法建立起重机的二维投影模型，分析四象限双臂防碰撞的问题。

J. Mendel, though, is selling four memorable styles-two clutches and two totes-of color-blocked broadtail, with prices starting at$ 4900 for a clutch made of the baby lamb and calf skin.

J.Mendel品牌推出了四款令人印象深刻的包包，手包和手提包各两款。手提包材质用的是大块颜色的阔尾羔羊皮。一款手包用羔羊皮和小牛皮制成，起始定价4900美元。

Methods Six cases of sex cord tumor with annular tubules, of which four were benign, the other two were malignant, were studied by clinical pathological observation, AgNOR count and clinical follow up.

方法：对6例卵巢环状小管性索瘤，良性4例，恶性2例，进行临床病理观察，AgNOR计数及术后随访。