单项选择题

女性，39岁，运动时胸闷1周。体检:胸骨左缘第3～4肋间可闻及粗糙的喷射性收缩期杂音。心电图示Ⅱ、Ⅲ导联出现病理性Q波。超声心动图示室间隔流出道部分向左心室内突出，二尖瓣前叶在收缩期向前方运动。该患者最可能的诊断是

A.室间隔缺损
B.风湿性主动脉瓣狭窄
C.肥厚型心肌病
D.急性心肌梗死
E.劳力型心绞痛

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单项选择题

患者男，46岁。活动后心悸、气短5个月，夜间不能平卧2周。超声心动图示：全心扩大，以左侧增大为主，二尖瓣前叶舒张活动振幅降低，瓣口开放小，呈钻石样双峰图形，余未见异常。该患者最可能的诊断是

A.风湿性心脏瓣膜病
B.肥厚性心脏病
C.扩张型心肌病
D.病毒性心肌炎
E.急性心包炎

问答题

问题21、电缆护层保护器的作用。某GIS变电站220kV电缆出线中间接头发生了短路击穿事故，经排查发现该电缆金属互层保护器已失效，且保护器从未按照要求开展过相关试验。分析认为，由于互层保护器缺陷未能及时发现，导致电缆投运后金属护层形成两端接地。护层中产生非常大的异常电流，导致中间接头接地线连接处发热严重，使该位置交联聚乙烯主绝缘过热软化及绝缘迅速劣化，最终导致主绝缘击穿故障。电缆护层保护器的作用是什么? Question 21 Function of cable sheath protector. A short circuit breakdown accident occurred in the middle joint of 220kV cable outlet in a GIS Substation. After investigation, it was found that the metal interlayer protector of the cable had failed, and the protector had never been tested according to the requirements. The analysis shows that the defects of the interlayer protector are not found in time, which leads to the formation of grounding at both ends of the metal sheath after the cable is put into operation. A very large abnormal current is generated in the sheath, which leads to serious heating at the ground wire connection of the intermediate joint, resulting in overheating softening and rapid deterioration of the XLPE main insulation at this position, and finally leading to the breakdown fault of the main insulation. What is the function of cable sheath protector?

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