【判断题】活性包装采用去氧剂、抗菌剂、异味消除剂、水分和二氧化碳等延长食品货架期,保证食品的安全性。
【判断题】The use of executive power is carried out by the Cabinet
【简答题】Pressure for financial reform is building in 1________. Germany, Europe’s largest economy, has been pushing for 2_________reform in the seen countries using the Euro. But German Chancellor Angela...
【单选题】The power is carried at high voltage over long distance with the help of wires called transmission lines.
A.
电通过电线以高压的形式长距离传输,这种电线被称为输电线路。
【判断题】活性包装采用去氧剂、抗菌剂、异味消除剂、水分和二氧化碳等延长食品货架期,保证食品的安全性。
【单选题】请计算附图的机构自由度,若机构中含有局部自由度、复合铰链和虚约时应具体指出,并判断该机构有没有确定的相对运动。 图片3.png
A.
机构有虚约束,在E或F处 n=4,PL=6,PH=0,F=3*4-2*6-0=0 自由度数为0,机构没有确定的相对运动。
B.
机构有局部自由度,在B处 n=5,PL=6,PH=1,F=3*5-2*6-1=2 原动件数不等于自由度数,机构没有确定的相对运动。
C.
机构有虚约束,在E或F处 n=6,PL=7,PH=1,F=3*6-2*7-1=3 原动件数不等于自由度数,机构没有确定的相对运动。
D.
机构有局部自由度,在B处 n=5,PL=7,PH=0,F=3*5-2*7-0=1 机构具有确定的相对运动。
【简答题】In aviation, pushback is an airport procedure during which an aircraft is pushed backwards away from an airport gate by external power. Pushbacks are carried out by pushback tractors or tugs. Although...
【单选题】The ______ motion is carried through the power train to the car wheels so that they rotate and the car moves.
【单选题】This force, or thrust, is carried through the connecting rod to the crankpin on the crankshaft. The crankshaft is given a powerful twist. This is known as the ( ) stroke.