【单选题】如图所示液压阀为( )。调节手柄,使阀口打开一定的开度。当P1进油时,流量( )。【图片】
【单选题】Different? Because sometimes it can be hard to pinpoint a __4__harm. “Internet addiction can also be called technology addiction. Taking selfies, using mobile phones are different aspects of this. Thi...
J.
positive K. vulnerable L. physical
【简答题】Different? Because sometimes it can be hard to pinpoint a __4__harm. “Internet addiction can also be called technology addiction. Taking selfies, using mobile phones are different aspects of this. Thi...
【单选题】Many sentences used to describe monetary policy, such as 'steering the economy to a soft landing' or 'a touch on the brakes', makes it sound like a precise science. Nothing could be further from the t...
A.
is comparable to driving a car.
B.
is similar to carrying out scientific work.
C.
will not influence the economy immediately.
D.
will have an immediate impact on the inflation rate.
【简答题】读“黄土高原地区”图,完成小题 小题1:图中表示太行山和秦岭的字母分别是 A.a、b B.b、c C.c、d D.a、d 小题2:下列关于黄土高原地区生态环境脆弱表现叙述错误的是 A.地面破碎,地表植被覆盖率低 B.水土流失严重,自然灾害频繁 C.自然灾害少,人类生存条件好 D.环境容易破坏,但很难恢复 小题3:“山坡坡栽树涯畔畔青,黄土高原有了好风景,狂沙那个不起尘少见,林果绕村绿满山”,歌曲展...
【单选题】下列关于肝细胞腺瘤的叙述,错误的是
B.
病理上是由正常或其高度不典型增生的肝细胞、血管及胆管构成
C.
MRI信号复杂,与其病变易出血坏死、脂肪积聚有关
【单选题】图示液压系统中右侧支路液压缸6的工作压力低于主油路的工作压力,其中阀3为( )。
【简答题】在图8-2所示的液压系统中,液压缸负载为F L ,液压缸无杆腔有效面积为A,减压阀的调定压力为P j ;溢流阀的调定压力为P y ,P y >P j 。试分析泵的工作压力由什么值来确定?