In heavy oil, not only the absolute concentrations but also the ratio indicators of neutral nitrogen compounds are too low to distinguish the oil migration path.

重质油中，无论是中性含氮化合物的绝对浓度或是其比值指标都降低，严重影响了原油运移途径的判别。

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Preserved liver, kidney, pancreas, adipose tissue in liquid nitrogen, and collected the liver, pancreas to 10%neutral formalin-fixed.

留取肝脏、肾脏、胰腺、脂肪组织以液氮保存，并留取肝脏以10%中性福尔马林固定。

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