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31.
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Li Xianzhou 《吉林大学学报(地球科学版)》1994,(4)
水厂麻粒岩中辉石的穆斯堡尔效应研究表明,斜方辉石的谱图为两组四极双峰,分别由M_1和M_2位上的高自旋态Fe ̄(2+)产生,而单斜辉石则为三组四极双峰,其中两组较强的双峰分别由M_1和M_2位上的Fe ̄(2+)产生,第二组弱双峰是由四面体和八面体位置上的Fe ̄(3+)共同产生的。水厂麻粒岩中辉石的有序程度高,并且斜方辉石有序度大大高于单斜辉石,而单斜辉石M_1、M_2位置的畸变程度高于斜方辉石。在压力相同的条件下,Fe ̄(2+)的有序度具有明显地温度效应,高温有利于Fe ̄(2+)做有序分布。 相似文献
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A hypothesis for the seismogenesis of a double seismic zone 总被引:1,自引:0,他引:1
The seismogenesis of a double seismic zone, in particular the lower layer of a double seismic zone, has not been adequately explained in the literature. On the basis of seismic data and geothermal structures along three well-studied cross-sections in the Kuril-Kamchatka and Japan subduction zones, we investigate the temperature/pressure conditions associated with seismogenic structures of the double seismic zones. the corresponding T/P loci seem to suggest that earthquakes observed in the lower layer and in the lower part (below approximately 130 ± 20 km) of the top layer of a double seismic zone were caused by metastable phase transition-a mechanism similar to that responsible for deep-focus earthquakes only at lower temperature/pressure conditions. Under this hypothesis, the wedge-shaped configuration of a double seismic zone is interpreted to represent the loci of the kinetic boundary of the phase transition. According to theoretical/experimental studies and the constraints imposed by our observations, a likely candidate for such a phase transition is the metastable Al-rich enstatite decomposing into the assemblage of Al-poor enstatite plus garnet. Earthquakes in the upper part of the top layer were most probably due to conventional mechanisms such as dehydration of subducted materials and/or facies change from basalt to eclogite. That the top layer involves more than one seismogenic mechanism is also implied by the distinct behaviour of seismicity in the vicinity of 130 ± 20 km. Because the presence of deviatoric stress is critical to the reaction rate of a metastable phase transition, it is inferred that single seismic zones are also caused by the same mechanisms, except that the implicit layer of a supposed double seismic zone is missing, due to the insufficient amount of appropriate metastable minerals or to the lack of appropriate deviatoric stresses in the source region. 相似文献
35.
A series of novel long-chain 3,4-dialkylthiophenes (C36–C54) was identified in a number of sediments ranging from Pleistocene to Cretaceous. The identifications were based on mass spectral characterisation, desulphurisation and mass spectral data of synthesised model compounds. These organic sulphur compounds are probably formed by sulphur incorporation into mid-chain dimethylalkadienes with two methylenic double bonds. These putative precursor lipids are unprecedented and may be considered rather unusual. The distribution of 3,4-dialkylthiophenes in sediments varies considerably with the depositional palaeoenvironment, indicating that these compounds have a potential as molecular markers reflecting changes in palaeoenvironment. 相似文献
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在伊朗卡尔赫水电站坝址工程勘察中,采用金刚石双管单动钻具和SM胶冲洗液进行取样钻探,用清水钻进压水试验,由于钻探工艺合理,钻探质量均达到了设计要求。 相似文献
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正交实验法在测绘仪器检定中的应用 总被引:2,自引:0,他引:2
在测绘生产和科研项目中,为了改革旧工艺或对新仪器,新产品,经常需要做多因素实验,如何安排多因素实验,是一个很值得研究的问题,文中以数字水准仪及标尺综合精度的检定为例,介绍了正交实验法在测绘仪器检定中的应用。 相似文献