桑托斯盆地白垩系湖相碳酸盐岩微生物礁滩的成因

巴西桑托斯盆地为典型的南大西洋被动大陆边缘含盐盆地,裂谷期白垩系Barra Velha组发育湖相碳酸盐岩微生物礁滩,是盐下含油气系统主要储层,叠层石微生物灰岩是组成微生物礁滩的主要岩石成分。本文通过地震剖面的振幅反射结构、钻井岩性剖面、岩心观察、岩心薄片分析,研究微生物礁滩主要特征。叠层石颗粒组成岩石格架,粒间孔发育,是优质储层,主要分布在东部隆起带上。鲕粒灰岩颗粒为叠层石,颗粒形态多样、大小不一,为叠层石微生物礁破碎后就近堆积、经波浪改造后的产物。桑托斯盆地湖相碳酸盐岩微生物礁滩的形成主要受控于古环境、水体深度变化及藻类改造作用。     

Extended light absorption and enhanced photoelectrochemical activity of palladium‐decorated hematite nanotubes prepared by photodeposition method

Palladium particles were deposited on hematite nanotube surfaces via a facile photodeposition method. Anodization method was then used for direct vertical growth of hematite nanotube arrays (HNTs) on a pretreated iron substrate. Field emission scanning electron microscopy, X‐ray diffraction, diffraction reflection spectroscopy and X‐ray photoelectron spectroscopy analyses were then used to carry out morphological and structural investigations. Compared with the bare HNTs, Pd‐decorated hematite films (Pd/HNTs) exhibit intense visible light absorption and show a red shift of the band edge. Pd/HNTs are more photoelectrochemically active than the non‐decorated films, according to chronoamperometry measurements. Thus, a promising methodology has been developed for the design of a simple and effective photoelectrode for application in photoelectrochemical water splitting systems.     

Simulations to Cover the Waterfront for Iron Oxide Catalysis

Hematite has been widely studied for catalytic water splitting, but the role of the interactions between catalytic sites is unknown. In this paper, we calculate the oxygen evolution reaction free energies and the surface adsorption distribution using a combination of density functional theory and Monte Carlo simulations to “cover the waterfront,” or cover a wide range of properties with a simulation of the hematite surface under working conditions. First, we show that modeling noninteracting catalytic sites provides a poor explanation of hematite's slow reaction kinetics. The interactions between the catalytic site may hinder catalysis through the strong interactions of *OH₂ and *OOH intermediates, which cause the reaction to revert back to the *O intermediate. Hence, neighboring interactions may be a possible reason for the abundant, experimentally observed *O intermediate on the surface. This study demonstrates how neighboring sites impact the energy required for catalytic steps, thus providing new avenues to improve catalysis by controlling neighboring site interactions.     

改进的KNN-SMOreg算法及在铀矿床典型蚀变矿物赤铁矿含量预测中的应用

赤铁矿作为铀矿床蚀变带中一种典型的蚀变矿物,在铀矿勘测过程中具有十分重要的指矿作用.传统的建模方法都以同样的概率来处理每个特征参数的重要性,但在实际建模过程中各个参数的重要性是有差别的,忽略此因素会直接影响赤铁矿预测的精度.针对此问题,本文提出一种基于属性关联的加权K近邻和支持向量机的新混合模型WKNN-SMOreg,...     

基于非线性能量分析的鲕滩储层预测方法

Teager Kaiser非线性能量（T K能量）可以归为振幅类地震属性,但有别于常规的振幅类地震属性,它与振幅的平方、频率的平方成正比。鲕滩储层中流体为油气时地震记录往往呈现“高频衰减” 现象,由于T K能量与频率平方成正比,因此含油气鲕滩储层内部T K能量弱。鲕滩储层与围岩的物性差别使储层顶和底边界形成“亮点”反射,相应的T K能量高,T K属性剖面背景越发“明亮”,而内部相对较“暗”,利用这些特征可以有效地进行鲕滩储层预测,实际资料的计算结果表明,基于非线性能量分析的鲕滩储层预测方法得到的鲕滩储层分布与实钻完全一致。     

Performance evaluation for selectivity of the flocculant on hematite in selective flocculation

Increased demand for iron ore necessitates the utilization of low-grade iron ore fines, slimes, and existing tailings. Selective flocculation can be an alternative physico-chemical process for utilizing these low-grade fines, slimes, and tailings. In selective flocculation, the most critical objective is the selection of proper reagents that will make floc of desired minerals. In present study, selective flocculation was applied to ultra-fine synthetic mixtures of hematite and kaolinite, and the Fe value was upgraded up to 65.78% with the reduction of Al₂O₃ and SiO₂ values to 2.65% and 3.66%, respectively. Here, degraded wheat starch was used as a flocculant.In this process, separation occurs on the basis of the selectivity of the flocculant. The selectivity of the flocculant can be quantified in terms of separation efficiency. Here, an attempt was also made to develop a correlation between separation efficiency and major operating parameters such as flocculent dose, pH value, and solid concentration to predict the separation performance.     

川东三叠系飞四段滩相鲕粒灰岩储层

根据对川东华蓥山地区陈家湾剖面地质调查,首次发现在飞四段存在滩相鲕粒灰岩地层.通过对该地层岩性、物性、孔隙类型、孔隙结构等特征研究,认为属于鲕粒滩相沉积,储集性能好.飞四段储层以溶孔为主,裂缝次之,属裂缝 溶孔型储层.飞四段滩相鲕粒灰岩储层的发现,为川东地区飞仙关组天然气的勘探提供了新的目的层.     

赤铁矿石隧道窑直接还原助还原剂的作用及机理

对隧道窑直接还原焙烧--磁选法处理低品位难选赤铁矿石进行了探讨,重点研究助还原剂NCP的作用及机理.以煤作还原剂,质量分数为20%,CCO和NCP为助还原剂,质量分数分别为15%和5%,在焙烧温度为1200℃,焙烧时间为8 h的条件下,可以得到铁品位92.61%、铁回收率92.38%的铁精矿.利用X射线衍射和扫描电镜对助还原剂NCP的作用机理进行分析.结果表明NCP可以与原矿中石英发生反应,生成硅钠石和钠长石,破坏原矿结构,使还原性气体更易与赤铁矿接触发生还原反应生成金属铁.     

Electrochemical Formation of Fe(IV)=O Derived from H2O2 on a Hematite Electrode as an Active Catalytic Site for Selective Hydrocarbon Oxidation Reactions

The high-valence iron species (Fe(IV)=O) in the cytochrome P450 enzyme superfamily is generated via the activation of O₂, and serves as the active center of selective hydrocarbon oxidation reactions. Furthermore, P450 can employ an alternate route to produce Fe(IV)=O, even from H₂O₂ without O₂ activation. Meanwhile, Fe(IV)=O has recently been revealed to be the reactive intermediate during H₂O oxidation to O₂ on hematite electrodes. Herein, we demonstrated the generation of Fe(IV)=O on hematite electrodes during the electrochemical oxidative decomposition of H₂O₂ using in situ UV-visible absorption spectra. The generation of Fe(IV)=O on hematite electrodes from H₂O₂ exhibited 100 mV lower overpotential than that from H₂O. This is because H₂O₂ serves not only as the oxygen source of Fe(IV)=O, but also as the additional oxidant. Finally, we confirmed that the Fe(IV)=O generated on hematite electrodes can serve as the catalytic site for styrene epoxidation reactions.     

3D Monte Carlo simulations on the aggregate structures of a suspension composed of cubic hematite particles

In the previous study, from the viewpoint of surface modification technology, we considered a quasi-2D suspension in thermodynamic equilibrium in order to investigate the characteristics of magnetic cubic particles on a material surface. The present study has been expanded to include 3D Monte Carlo simulations of a suspension of magnetic cubic particles in order to discuss a regime change in the structures of cubic particle aggregates. We attempt to elucidate the dependence of a regime change in the aggregate structures on a variety of factors. The main results obtained here are summarised as follows. If the magnetic interaction strength is sufficiently large, closely packed clusters are formed by repeat and expansion of a cluster unit composed of eight particles, which may be the most preferred configuration as it gives rise to a minimum energy. A regime change in the internal structure of aggregates appears in a narrow range with increasing magnetic interaction strength. As the applied magnetic field strength is increased, closely packed clusters collapse and are transformed into wall-like clusters that are formed along the magnetic field direction. An increase in the volumetric fraction of particles induces a regime change from thick chain-like clusters to the formation of wall-like clusters.