掘到第五下或是第六下时，鹤嘴锄碰到了一样铁东西。

At the fifth or sixth blow the pickaxe struck against an iron substance.

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磁铁矿颗粒氧化按温度划分为两段，在较低温度下主要是铁离子扩散，较高温度下氧离子扩散的扩散能力增强。

Oxidation of magnetite grains is divided into tow stages, according to temperature, and iron ion diffuses at lower temperature and diffusion amount of oxygenic ion increases at higher temperature.

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环状沟土壤浸施铁肥在不断根的情况下很难被根吸收，断根情况下吸收、输机制与根系输液相同。

Generally, it is difficult to be absorbed by roots when iron fertilizer was drenched into soil.

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So iron left to own devices in the atmosphere in the presence of a little bit of water, with the water form iron oxide.

铁在大气中，在存在,少量水的条件下，大气会开始与水结合产生氧化铁。

麻省理工公开课 - 热力学与动力学课程节选

Now in this particular reaction, I've got hydrogen gas, iron solid. Those already are elements in their most stable forms at room temperature and pressure.

特定的反应中，我有氢气,固态铁，这些都已经是,处于室温和常压下,最稳定的元素单质。

麻省理工公开课 - 热力学与动力学课程节选

Iron as an element is a solid. That's it's most stable state at room temperature and pressure, right, and so on. And then we can figure out heats of formation.

铁单质是固态,这是他在室温和常压下,最稳定的状态，然后我们,可以算出生成热，现在这个。

麻省理工公开课 - 热力学与动力学课程节选