A．The temperature difference on both sides of each wall is proportional to its thermal conductivity 各层壁面两侧的温差与其导热系数成正比 B．The temperature difference on both sides of each wall is proportional to its thickness 各层壁面两侧的温差与其厚度成正比 C．The temperature difference on both sides of each layer wall is proportional to its logarithmic average are各层壁面两侧的温差与其对数平均面积成正比 D．The temperature difference on both sides of each layer wall is proportional to its logarithmic mean diameter 各层壁面两侧的温差与其对数平均直径成正比
