For a loss modulation where the threshold carrier density may change, the neglected term may become comparable to the retained first order small quantity.

在损耗调制的情况下，系统变化前后的阈值载流子密度不同，被忽略的二阶小量可能会达到与一阶小量可比拟的程度。

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The critical current density of pure MgB2 is comparable to that of triniobium tin at low magnetic fields but falls off much more rapidly at higher fields.

在低磁场下，硼化镁的临界电流密度与三铌化锡相当，但是在较高的磁场下却下降得很快。

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