当一个线圈作为发射线圈,另一个线圈作为接收线圈时,射频TR开关将不起作用。()
A. 对
B. 错
相控阵线圈能提高图像的信噪比,改善薄层和高分辨扫描的图像质量,但延长了扫描时间。()
A. 对
B. 错
Listen to a passage. Fill in the blanks with the information you have heard.[音频]Natural beauty:1) The beauty of the natural world seems to cause1in everyone despite their2 ,3, or 4.2)5 seem to have little impact on what we find beautiful in the natural world.Human beauty:1) Our perception of human beauty changes across6 and over7.2) It is easy to see a person's 8 but hard to discover a person's9.
某企业方圆400米,存有液氧和液氨,临界值分别为200吨和10吨,存量分别是120吨和25吨,试计算R值,并指出重大危险源级别。(a可取值为1.0)