用光导纤维作为传输光的媒介质的思想是美籍中国科学家高锟博士于1966年首先提出的

题型:填空题

问题:

用光导纤维作为传输光的媒介质的思想是美籍中国科学家高锟博士于1966年首先提出的,经过各国科学家的努力,高质量、高速率的光纤通信终于实现了,并已成为现代生活中最主要的通信方式.这种通信方式是用 _________ 来携带信息传到远方.

考点:光纤通信
题型:填空题

图(a)为测量物块与水平桌面之间动摩擦因数的实验装置示意图。

 

实验步骤如下: 

①用天平测量物块和遮光片的总质量M.重物的质量m:用游标卡尺测量遮光片的宽度d;用米尺测最两光电门之间的距离s; 

②调整轻滑轮,使细线水平; 

③让物块从光电门A的左侧由静止释放,用数字毫秒计分别测出遮光片经过光电门A和光电门B所用的时间△tA和△tB,求出加速度a; 

④多次重复步骤③,求a的平均a 

⑤根据上述实验数据求出动擦因数μ。

回答下列为题:

如果细线没有调整到水平,由此引起的误差属于()。(填“偶然误差”或”系统误差”)

题型:填空题

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题型:填空题

男,45岁,咳嗽,咯血2月余,有20余年吸烟史,结合影像学检查,最可能的诊断是()

A.肺结核

B.小细胞肺癌

C.肺脓肿

D.肺囊肿

E.肺错构瘤

题型:填空题

高温矿井井巷施工中的温、湿度要求是(  )。

A.工作面的相对湿度为60%时,空气温度不得超过20℃

B.工作面的相对湿度为60%时,空气温度不得超过25℃

C.工作面的相对湿度为90%时,空气温度不得超过28℃

D.工作面的相对湿度为90%时,空气温度不得超过30℃

题型:填空题

感觉倒错()。

A.痛觉和温度觉障碍,触觉正常

B.较强的刺激才能感受,且需经过一段潜伏期,出现一种强烈的、定位不明确的难受的感觉,刺激停止后还有后作用

C.轻微刺激产生强烈的感觉

D.冷刺激产生热的感觉

E.刺激不产生感觉

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