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81.
82.
以铸态Ni-Cr-Fe合金为试样,于1 050℃湿氢气氛下恒温氧化20 h。通过氧化增重、SEM/EDS以及薄膜X-射线衍射等方法研究了氧分压对该合金在弱氧化性气氛下氧化成膜特性的影响。结果表明:表面氧化膜从外到内氧化物组成依次为:MnCr2O4、Cr2O3以及SiO2。氧化膜的厚度、组成及形貌与体系的氧分压密切相关,中等氧分压(15.9×10-18atm)有利于表面尖晶石的形成;较低氧分压有利于形成厚而多孔的氧化膜,而高氧分压则趋向于形成薄而致密的氧化膜。 相似文献
83.
Isabel Margarida Horta Ribeiro Antunes Ana Margarida Ribeiro Neiva João Manuel Farinha Ramos Paulo Bravo Silva Maria Manuela Vinha Guerreiro Silva Fernando Corfu 《Chemie der Erde / Geochemistry》2013
In the Segura area, Variscan S-type granites, aplite veins and lepidolite-subtype granitic aplite-pegmatite veins intruded the Cambrian schist-metagraywacke complex. The granites are syn D3. Aplite veins also intruded the granites. Two-mica granite and muscovite granite have similar ages of 311.0 ± 0.5 Ma and 312.9 ± 2.0 Ma but are not genetically related, as indicated by their geochemical characteristics and (87Sr/86Sr)311 values. They correspond to distinct pulses of magma derived by partial melting of heterogeneous metapelitic rocks. Major and trace elements suggest fractionation trends for: (a) muscovite granite and aplite veins; (b) two-mica granite and lepidolite-subtype aplite-pegmatite veins, but with a gap in most of these trends. Least square analysis for major elements, and modeling of trace elements, indicate that the aplite veins were derived from the muscovite granite magma by fractional crystallization of quartz, plagioclase, K-feldspar and ilmenite. This is supported by the similar (87Sr/86Sr)311 and δ18O values and the behavior of P2O5 in K-feldspar and albite. The decrease in (87Sr/86Sr)311 and strong increase (1.6‰) in δ18O from two-mica granite to lepidolite-subtype aplite-pegmatite veins, and the behaviors of Ca, Mn and F of hydroxylapatite indicate that these veins are not related to the two-mica granite. 相似文献
84.
南海沉积物漫反射光谱反映的220ka以来东亚夏季风变迁 总被引:1,自引:0,他引:1
对南海越南岸外“太阳号”95航次17954孔220ka以来的沉积样品进行了漫反射光谱分析, 并从中提取F1和F2两个主因子及亮度和红度等漫反射光谱特征值, 发现漫反射光谱F1值和亮度反映了沉积物中的碳酸盐含量, 而漫反射光谱F2值和红度反映了沉积物中的铁氧化物含量, 后者可用作东亚夏季风的替代性指标.17954孔沉积物的漫反射光谱F2值显示, 倒数第二次冰消期东亚夏季风快速增长时间约在129ka; 本次工作还发现东亚夏季风在两次冰消期前的氧同位素2阶段和6阶段晚期各有一个异常强盛的时期.漫反射分析结果显示东亚夏季风主要受控于太阳辐射强度变化, 并明显地受低纬地区气候的影响. 相似文献
85.
The localization of nitric oxide synthases (NOS) is dealed with in the developing gonads of amphioxus Branchiostoma belcheri tsingtauense. It was found by NADPH-diaphorase staining that (1) NOS activity was present in the nuclear membranes of germinal vesicles during the entire period ofoocyte development; (2) NOS was localized in both the nuclear membranes and the perinuclear region of cytoplasm in the vitellogenetic oocytes; (3) NOS was relocated in the cortical layer in the mature egg; (4) NOS activity was present in spermatocytes, but not in the spermatogonia in the middle of October; (5) NOS was detected in both spermatozoa and spermatids as well as spermatocytes during the breeding season. This is the first report on the distribution pattern of NOS in the developing gonads in protochordates. These results suggest a role for NOS in the functioning of the nuclear membranes and yolk synthesis during oogenesis and in cell division and differentiation during spermatogenesis. 相似文献
86.
小河金矿的细菌预氧化研究 总被引:2,自引:0,他引:2
陕西旬阳小河金矿的浮选金精矿含砷(20-27%),采用细菌预氧化时较为困难。采用不同方式对有T.f菌进行驯化,有效地提高了细菌的氧化活性,金的浸出率从0.6%提高到85.12%。 相似文献
87.
利用Minolta CM-2002光谱光度计对南黄海陆架136个短柱样品20~25cm段的沉积物进行了颜色反射率数据测量,通过化学元素、粒度、磁化率等来确定影响沉积物颜色反射率变化的成分和因素,介绍了反射率光谱的一阶导数和因子分析的方法。分析结果表明,南黄海陆架沉积物颜色反射率受控于沉积物中的铁氧化物、有机质以及粘土矿物和钙质生物碎屑含量。主因子F1指示氧化环境,并与陆源物质相关,F2指示弱氧化环境,F3指示弱还原环境,主因子的波长范围分别是405~445 nm和495~595 nm,605~695 nm,445~485 nm。 相似文献
88.
Recent work on the Panzhihua intrusion has produced two separate models for the crystallisation of the intrusion:(1) low-Ti,high CaO and low H2O(0.5 wt.%) parent magma(equivalent to Emeishan low-Ti basalt) at FMQ;and(2) high-Ti,low CaO and higher H2O(>1.5 wt.%) parent magma(equivalent to Emeishan high-Ti basalt) at FMQ + 1.5.Modelling of these parent magma compositions produces significantly different results. We present here detailed f(O2) and H2O modelling for average compositions of both Emeishan high-Ti and low-Ti ferrobasalts in order to constrain the effects on crystallisation sequences for Emeishan ultra-mafic -mafic layered intrusions.Modelling is consistent with numerous experimental studies on ferro-basaltic magmas from other localities(e.g.Skaergaard intrusion).Modelling is compared with the geology of the Panzhihua intrusion in order to constrain the crystallisation of the gabbroic rocks and the Fe-Ti oxides ore layers.We suggest that the gabbroic rocks at the Panzhihua intrusion can be best explained by crystallisation from a parent magma similar to that of the high-Ti Emeishan basalt at moderate H2O contents(0.5-1 wt.%) but at the lower end of TiO2 content for typical high-Ti basalts(2.5 wt.%TiO2). Distinct silicate disequilibrium textures in the Fe-Ti oxide ore layers suggest that an influx of H2O may be responsible for changing the crystallisation path.An increase in H2O during crystallisation of gabbroic rocks will result in the depression of silicate liquidus temperatures and resultant disequilibrium with the liquid.Continued cooling of the magma with high H2O then results in precipitation of Mt-Uv alone. The H2O content of parent magmas for mafic layered intrusions associated with the ELIP is an important variable.H2O alters the crystallisation sequence of the basaltic magmas so that at high H2O and f(O2) Mt -Uv crystallises earlier than plagioclase and clinopyroxene.Furthermore,the addition of H2O to an anhydrous magma can explain silicate disequilibrium texture observed in the Fe-Ti oxide ore layers. 相似文献
89.
Spatial heterogeneity of soil mineral oxide components in depression between karst hills,Southwest China 总被引:3,自引:0,他引:3
Hu Du Kelin Wang Wanxia Peng Fuping Zeng Tongqing Song Hao Zhang Shiyang Lu 《中国地理科学(英文版)》2014,24(2):163-179
In karst regions,the spatial heterogeneity of soil mineral oxides and environmental variables is still not clear.We investigated the spatial heterogeneity of SiO2,Al2O3,Fe2O3,CaO,MgO,P2O5,K2O,and MnO contents in the soils of slope land,plantation forest,secondary forest,and primary forest,as well as their relationships with environmental variables in a karst region of Southwest China.Geostatistics,principal component analysis(PCA),and canonical correlation analysis(CCA)were applied to analyze the field data.The results show that SiO2was the predominant mineral in the soils(45.02%–67.33%),followed by Al2O3and Fe2O3.Most soil mineral oxide components had a strong spatial dependence,except for CaO,MgO,and P2O5in the plantation forest,MgO and P2O5in the secondary forest,and CaO in the slope land.Dimensionality reduction in PCA was not appropriate due to the strong spatial heterogeneity in the ecosystems.Soil mineral oxide components,the main factors in all ecosystems,had greater influences on vegetation than those of conventional soil properties.There were close relationships between soil mineral oxide components and vegetation,topography,and conventional soil properties.Mineral oxide components affected species diversity,organic matter and nitrogen levels. 相似文献
90.
Magneticmineralsintheloess paleosolseriesaccountforabout 1 % -2 %ofthetotal (LiuTungshengandZhangZhonghu ,1 962 ) .Duetotheiraerolianorigin ,themagneticmineralsarecomplicatedincomposition ,largeingrainsizerange ,andsignificantlydifferentincrystallinity .Asaresult,researchonthesemagneticmineralswouldbesetwithalotofdifficulties.Previousre searchersemployedopticalmicroscopic ,X raydiffractionandM ssbauerspectrometrictechniquestostudythemagneticmineralsintheloess paleosolseries,andchieflyontheb… 相似文献