Positive displacement, helical gear pumps are well suited for pumping oil because （）
1、北京勤邦（原望尔）试剂盒和美国helice试剂盒选取4-parameterC
北京勤邦（原望尔）试剂盒和美国helice试剂盒选取4-parameterCurve参数A正确B错误
2、A variable displacement system of hydr
A variable displacement system of hydraulic drives consists of （）.Aa variable displacement axial piston pumpBa constant displacement axial piston pumpCa reciprocating piston pumpDa centrifugal pum
3、As the displacement of a vessel increa
As the displacement of a vessel increases，the detrimental effect of free surface（）.AincreasesBdecreasesCremains the sameDmay increase or decrease depending on the fineness of the vessel's form
4、Each drilling unit equipped with helic
Each drilling unit equipped with helicopter fuel storage tanks must have the tanks installed as far as practicable from the（）.Alanding area and sources of vapor ignitionBmain deckCengine roomDdrill floor
5、The cubic inch(or liter) displacement
The cubic inch(or liter) displacement of a cylinder is determined by the diameter of the piston and the （）Alength of the crankshaftBvolume of the clearance spaceCweight of pistonDlength of the stroke
6、The upward pressure of displaced water
The upward pressure of displaced water is called（）.AbuoyancyBdeadweightCdraftDfreeboard