家庭装修如果要挪动燃气管线,必须经哪个部门同意,以免引起燃气泄漏()。
查看答案
During maneuvering operations for a direct reversing large, low-speed, main propulsion diesel engine, which of the following actions is used to stop the shaft from turning prior to reversing the engine rotation?()
A. Flywheel inertia
B. Admission of starting air
C. The way of the vessel
D. securing of fuel to the cylinder
用于分离质粒 DNA的细菌培养浓度达到 0.8×10 细胞/ml 时,即可通过离心收集菌体。收集菌体使用定角转子,离心的速度以()为宜。