原位二氧化碳泡沫驱提高采收率实验

原位CO₂ 泡沫驱是一种很有潜力的提高采收率技术。通过原位CO₂ 泡沫驱提高采收率实验,优化了生气体系、泡沫体系以及注入参数,得到了最佳的注入量、注入速度和适用的渗透率级差范围。研究结果表明,在温度 为70℃,地层水矿化度为10000mg/L条件下,得到可以作用于地层深部的原位CO₂ 泡沫体系,其配方为：2.1% 碳酸氢铵+1.6%醋酸+9.5%氯化铵+0.1%α-烯烃磺酸钠AOS+0.1%油酸酰胺丙基甜菜碱DHSB,泡沫体积可达 810 mL,泡沫综合指数为15552mL·min。该体系形成的泡沫在油藏中部具有较高黏度和较大弹性的特性,能够 有效封堵高渗通道,表现出良好的封堵能力。在渗透率级差为6左右时,原位CO₂ 泡沫体系注入速度控制在1.0 mL/min左右,注入段塞量控制在0.3PV,能够发挥最佳的调驱效果。研究还发现,该泡沫体系在渗透率级差为 3.9～13.7的非均质储层中能有效提高采收率,而在渗透率级差为15.6的条件下,虽然未能显著提高低渗层采收率,但在高渗管中仍然有一定的洗油作用。本研究为原位CO₂ 泡沫驱技术的应用和优化提供了重要参考。     

Improved cycling stability of the capping agent-free nanocrystalline FeS<Subscript>2</Subscript> cathode via an upper cut-off voltage control

Transition metal chalcogenides such as FeS₂ are promising electrode materials for energy storage. However, poor rate performance and low cycling stability hinder the practical application of FeS₂ cathode in secondary batteries. In this study, highly pure pyrite FeS₂ nanocrystals (NCs) with octahedral shape and 200–300 nm size have been synthesized via a facile and environmentally benign approach based on a surfactant-free aqueous reaction. Combined with a compatible ether electrolyte, the prepared FeS₂ NCs, despite their dimension far beyond the quantum confined regime, could achieve high utilization and reversibility as a cathode active material due to the well-defined crystal structure and the uncapped rough surfaces. Furthermore, we find that the last charging voltage step of FeS₂ only contributes a minor capacity but caused severe capacity fading due to the formation of soluble polysulfides. By suppressing this step through setting a proper upper cut-off voltage, the cycle life of the Li/FeS₂ cell is dramatically improved. The Li/FeS₂ cell running over a voltage window of 1.0–2.4 V at 1C delivers an initial capacity of 486.1 mA h g^?1, slightly lower than that running over 1.0–3.0 V (561.1 mA h g^?1), but outperforms the latter substantially after 500 cycles (367 mA h g^?1 vs 315 mA h g^?1), corresponding to a capacity decay rate as low as 0.048% per cycle. Our results provide a meaningful approach for the development of not only the advanced FeS₂ material for long-life rechargeable batteries, but also other transition metal chalcogenide nanomaterials for a variety of potential applications.     

抛丸工艺在钢铁线材表面处理上的应用

国外抛丸机型不能满足国内企业生产量大的需求,自主创新研发了适应国内市场需求的PMW5300型整卷线材抛丸机.主要从表面清洁度、表面粗糙度、表面硬度、线材损耗、环保除尘排放等5个方面分析影响线材品质、抛丸效果的因素;针对中高碳钢、低碳钢、冷镦钢、不锈钢等不同材质的金属线材,根据实践经验,给出PMW5300型整卷线材抛丸机...     

基于光纤环输出光斑旋转的位移传感器图像处理方法

光纤传感器以其耐水、耐高温、抗电磁干扰等优势备受青睐,通过介绍基于光纤环输出光斑旋转的位移传感器的原理与实验现象,提出了一种基于质心计算的图像处理方法,该方法能更加精确地测量光斑旋转角度。该方法通过以旋转轴为中心,对每一个光斑分别跟踪求取质心坐标,得到每个光斑对应的角度,并计算角度旋转变化的值,从而得出该位移传感器随位移线性变化的关系。实验结果表明,该方法更加准确且有效。     

Chemical routes toward long-lasting lithium/sulfur cells

Lithium/sulfur (Li/S) cells have great potential to become mainstream secondary batteries due to their ultra-high theoretical specific energy. The major challenge for Li/S cells is the unstable cycling performance caused by the sulfur’s insulating nature and the high-solubility of the intermediate polysulfide products. Several years of efforts to develop various fancy carbon nanostructures, trying to physically encapsulate the polysulfides, did not yet push the cell’s cycle life long enough to compete with current Li ion cells. The focus of this review is on the recent progress in chemical bonding strategy for trapping polysulfides through employing functional groups and additives in carbon matrix. Research results on understanding the working mechanism of chemical interaction between polysulfides and functional groups (e.g. O–, B–, N–and S–) in carbon matrix, metal-based additives, or polymer additives during charge/discharge are discussed.

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框架免动力加速对流锚杆多年冻土#br# 边坡支护结构的提出及理论计算方法

针对多年冻土边坡的冻融滑塌问题,结合无动力通风技术、通风管降温技术和锚固技术,提出一种新型框架免动力加速对流锚杆边坡支护结构,并阐述了新型结构的工作机理。基于通风工程和传热学理论,建立免动力加速对流锚杆与土体换热的计算模型,给出免动力加速对流锚杆的热效应理论计算方法;基于Winkler弹性地基梁理论,建立框架免动力加速对流锚杆边坡支护结构与土体协同工作的计算模型,提出框架免动力加速对流锚杆边坡支护结构的力学效应理论计算方法。结合算例,采用提出的理论计算方法对框架免动力加速对流锚杆边坡支护结构的热-力学效应进行分析,并利用自主研发的框架免动力加速对流锚杆支护多年冻土边坡的水热力耦合分析软件对提出的理论计算方法进行验证,结果表明：①无动力风帽极大提升了免动力加速对流锚杆的通风能力,增大了外界冷空气与边坡内部土体之间的对流换热强度,促使多年冻土边坡内冻融交界面逐年抬升;②框架免动力加速对流锚杆边坡支护结构减弱了边坡土体的冻胀作用,能够提高多年冻土边坡的稳定性;③文章提出的理论计算方法具有一定的准确性和合理性,可为框架免动力加速对流锚杆边坡支护结构的设计提供理论依据。     

α-Fe2O3/alkalinized C3N4 heterostructure as efficient electrocatalyst for oxygen reduction reaction

Journal of Materials Science - A nanocomposite of α-Fe2O3/alkalinized C3N4 (α-Fe2O3/A-C3N4) electrocatalyst for oxygen reduction reaction (ORR) was synthesized by a simple in situ...     

改性聚酯合成中共缩聚的研究

本文着重研究了ＰＴＡ—ＡＤＡ—ＥＧ三元共缩聚的反应规律，对三元共缩聚过程的主要工艺参数：聚合时间、聚合温度及第三单体（ＡＤＡ）加入量等进行分析研究，结果表明它们与共聚酯质量有关。     

Extending Cycle Life of Mg/S Battery by Activation of Mg Anode/Electrolyte Interface through an LiCl‐Assisted MgCl2 Solubilization Mechanism

Non‐nucleophilic electrolytes that can reversibly plate/strip Mg are essential for realizing high‐performance rechargeable Mg/S batteries. In contrast to organometallic electrolytes, all‐inorganic electrolytes based on MgCl₂‐AlCl₃ complexes are more cost‐effective and hold better stability to air and moisture. A recently developed electrolyte that contains tetrahydrofuran solvated divalent Mg cation, [Mg·6THF][AlCl₄]₂, has exhibited decent compatibility with the sulfur cathode. However, it suffers a large overpotential and short cycle life, which hinders its applications in Mg/S batteries. Here, an efficient plating/stripping of Mg is realized successfully by using LiCl to dissolve MgCl₂ from the electrolyte/electrode interface. As a result, the overpotential of Mg plating/stripping is remarkably reduced to 140/140 mV at a current density of 500 µA cm^?2. Both experiments and density functional theory (DFT) calculations reveal that the LiCl‐assisted solubilization of MgCl₂ facilitates the exposure of fresh surface on the Mg anode. Utilizing such an LiCl‐activation strategy, Mg/S full batteries with a significantly extended cycle life of over 500 cycles, as well as coulombic efficiency close to 100%, are achieved successfully. This work demonstrates the role of LiCl‐assisted interface activation on extending the cycle‐life Mg/S batteries with all‐inorganic electrolytes.