如图所示,等腰直角三角形ABC的区域内有一垂直于纸面向内的匀强磁场,磁感应强度为

题型:问答题

问题:

如图所示,等腰直角三角形ABC的区域内有一垂直于纸面向内的匀强磁场,磁感应强度为B,已知AB=2a,现有一束质量为m,带电量为q的正粒子在AB的中点O处沿着垂直与AB的方向以v0打入磁场,在AC边上放置一块足够大的荧光屏,当v0=

3aqB
m
时,

(1)判断粒子能否打到荧光屏上.

(2)求粒子在磁场中运动的时间.

考点:带电粒子在匀强磁场中的运动
题型:问答题

斗轮堆取料机的除尘装置采用()形式电机驱动。

A.单速电机

B.双速电机

C.三速电机

题型:问答题

病历摘要:患者男性,38岁,间歇性无痛性全程肉眼血尿1天。血尿呈洗肉水样,无血块。无尿频、尿急和尿痛。无排尿费力。无腰痛。平素健康。体检:双肾区无叩击痛,双侧输尿管行程无压痛,耻骨上区无膨隆和压痛。

哪些不是首选的筛选检查项目?()

A.肾脏ECT

B.同位素骨扫描

C.尿细胞学检查

D.盆腔CT

E.盆腔MRI

F.泌尿系B超

题型:问答题

病历摘要:患者男性,58岁,平素情绪容易激动,2年前发现“高血压”平时服用降压药,血压控制良好,但患者时有头痛而眩,多为两侧,心烦易怒,夜寐不宁,多梦,口苦,今日头痛加剧遂来医院求诊,症见:头胀痛,两侧俱痛,相对烦躁,口苦,查体:舌质红,苔薄黄,脉弦数。

头痛的辨证要点是什么?()

A.辨头痛虚实

B.辨头痛部位

C.辨头痛所属脏腑

D.辨头痛性质

E.辨外感头痛或内伤头痛

F.辨头痛分期

G.辨头痛轻重

题型:问答题

Contrary to common belief, social media websites such as Facebook do not weaken personal ties, they strengthen them in unique ways for different age groups, according to a new study.

The rapid spread of Facebook, which has more than 500 million users worldwide, has prompted concerns about its negative effects, but researchers at the University of Texas have reached a different conclusion.

"Our findings suggest that Facebook is not replacing face-to-face interactions between friends, family and colleagues," said S.Craig Watkins, an associate professor of radio, TV and film who headed the research team.

"In fact, we believe there is sufficient evidence that social media afford opportunities for new expressions of friendship, intimacy and community."

The researchers questioned 900 college students and recent graduates about how and with whom they interact on Facebook.

More than 60 percent of Facebook users said posting status updates was among the most popular activities, followed by 60 percent who wrote comments on their profile and 49 percent who posted messages and comments to friends.

The researchers also found that although about the same number of men and women use Facebook, they do so in different ways.

"There is a noteworthy difference in aims in how to use a tool like Facebook.We found that for women the content tends to be more affectionate, and (they) are especially interested in using it for connection," said Watkins.

"For men, it's more functional," he added.

Watkins pointed out that, for example, women are more likely to post pictures of social gatherings with friends, while men are more likely to post pictures of hobbies, or post a political or pop-culture related link.

小题1:What's the popular viewpoint of ordinary people about the function of social media websites? They think ____.

A.It is positive to personal ties

B.It has negative effects on personal ties

C.It makes no difference to personal ties

D.It has both good and bad effects to personal ties小题2:What's the meaning of the underlined word in the second paragraph?

A.resulted from

B.had

C.showed

D.produced小题3:What do Facebook users like to do mostly on Facebook? They like to ____.

A.create new expressions of friendship '

B.wrote comments on their profile

C.update their personal statuses

D.post messages and comments to friends小题4:According to the study, ____.

A.Men concentrate more on the functions of Facebook

B.Much more men use Facebook than women

C.Men and women use a tool like Facebook for the same aim

D.Facebook is taking the place of face-to-face interactions between friends

题型:问答题

钢筋连接方法不包括( )连接。

A.对接
B.机械
C.焊接
D.绑扎

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