发布时间:2025-02-03 12:03:39
好像没有这种说法吧,超声波换能器都有发射角,一般是6-15度。发射角跟陶瓷的材料,形状,谐振频率有关。发射角越小,能量越集中,作用距离越远,抗干扰能力越强
请问中国灯具市场国产品牌的前十名和国外品牌的前十名各是什么。。还有综合起来前十名。
2025-02-03 12:03:39 2025-02-03 12:03:39 2025-02-03 12:03:39 2025-02-03 12:03:39电工从电工从业资格证到初级电工证到中级电工证再到高级电工证要多久可以考完
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