各向异性晶体中,极化是各向异性的,介电常数的取值与方向无关。
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好的家庭教育课程,不是让家长能说会道,而是设计一套体系帮助家长真正行动起来。
在一定的环境条件下或某种遗传背景下才能表现的突变性状称为非条件型突变。
External quantum efficiency (EQE) hEQE of an LED represents the efficiency of conversion from electrical quanta, i.e. electrons, that flow in the LED to optical quanta, i.e.photons, that are emitted into the outside world.