在电力系统出现失步状态时,应采用失步解列装置,下列解列地点的选择原则中正确的是(

题型:多项选择题

问题:

在电力系统出现失步状态时,应采用失步解列装置,下列解列地点的选择原则中正确的是( )。

A.送端孤立的大型发电厂,在失步时应优先切除部分机组,以利其他机组再同步;

B.地区电网与主系统的联络线;

C.解列后的两侧系统,各自可以同步运行;

D.有2个及以上联系通道中选择一个通道进行解列。

考点:注册电气工程师发输变电专业继电保护、安全自动装置及调度自动化
题型:多项选择题

如图所示,甲、乙、丙三小球分别位于如图所示的竖直平面内,甲、乙在同一条直线上,甲、丙在同一条水平线上,P点在丙球正下方.某时刻,甲、乙、丙同时开始运动,甲以水平速度v0平抛,乙以水平速度v0沿水平面向右做匀速直线运动,丙做自由落体运动,则下列说法错误的是(  )

A.无论初速度v0大小如何,甲、乙、丙三球一定会同时在P点相遇

B.若甲、乙、丙三球同时相遇,则一定发生在P点

C.若甲、丙两球在空中相遇,此时乙球一定在P点

D.若甲、乙两球在水平面上相遇,此时丙球一定在P点

题型:多项选择题

鼓膜切开术的适应证是()

A.穿孔太小,引流不畅

B.炎症确已消退,鼓膜穿孔长期不愈者

C.有并发症可疑,但无需立即行乳突手术

D.全身及局部症状较重,鼓膜明显膨出,经一般治疗无明显减轻

E.鼓膜穿孔后大量耳漏

题型:多项选择题

下列哪一项不是必须紧急施行透析的指征()

A.因体液超载而引起的充血性心衰

B.未能纠正的进行性酸中毒

C.经治疗无效的高钾血症

D.尿毒症性心包炎

E.血肌酐高达6mg/dl

题型:多项选择题

碘﹣127是一种核内有53个质子和74个中子的原子,该种碘原子的核外电子数为()。

A.21

B.53

C.74

D.127

题型:多项选择题

(1) The word "addiction" usually makes you think of alcohol or drugs, but in modern-day society we are seeing some new kinds of addictions. Some people are compulsive (难以自制的) shoppers. Others find it impossible to pull themselves away from their work. Still others spend countless hours watching TV or playing computer games.
(2) Over the years, shopping has become a very common activity. Many people enjoy going to stores more and more every day, but it’s more than a common hobby for some of them. They have turned into shopaholics. They are people who simple enjoy shopping and walking around spending money without being able to stop doing it. They are hooked on shopping and usually buy things that they don’t need. Even though they don’t have enough money, they buy everything they want.
(3) The question is, why do they have this addiction There isn’t a specific answer. Some people go shopping when they are sad, worried, upset or lonely, and they want to feel better. They use this activity as a way to forget their problems. Shopaholics say that they feel more important and better after they buy something. They also tend to have this addiction when they feel guilty.
(4) Shopaholism seems to be a harmless addiction, but it can ______. Some of them can be psychological. If this is the case, people addicted to shopping should go to a support group to help them break this habit. However, the process, like for most addictions, is long, and they suffer a lot. It can also cause financial problems. They just think about satisfying their feelings, so they spend money they don’t have. They get deep in debt, and they can even go bankrupt and get sent to prison.

List three activities that might develop into addictions based on the text. (Please answer within 8 words)
①______
②______
③______

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