具有良好可再生性的新型二氧化硅磁性氧化石墨烯纳米复合材料

Graphene oxide (GO) wrapped Fe₃O₄ nanoparticles (NPs) were prepared by coating the Fe₃O₄ NPs with a SiO₂ layer, and then modifying by amino groups, which interact with the GO nanosheets to form covalent bonding. The SiO₂ coating layer plays a key role in integrating the magnetic nanoparticles with the GO nanosheets. The effect of the amount of SiO₂ on the morphology, structure, adsorption, and regenerability of the composites was studied in detail. An appropriate SiO₂ layer can effectively induce the GO nanosheets to completely wrap the Fe₃O₄ NPs, forming a core-shell Fe₃O₄@SiO₂@GO composite where Fe₃O₄@SiO₂ NPs are firmly encapsulated by GO nanosheets. The optimized Fe₃O₄@SiO₂@GO sample exhibits a high saturated adsorption capacity of 253 mg·g?1 Pb(II) cations from wastewater, and the adsorption process is well fitted by Langmuir adsorption model. Notably, the composite displays excellent regeneration, maintaining a ~90% adsorption capacity for five cycles, while other samples decrease their adsorption capacity rapidly. This work provides a theoretical guidance to improve the regeneration of the GO-based adsorbents.     

微波预处理对复杂铜矿磨矿及浮选动力学的影响

The effect of CaCO₃, Na₂CO₃, and CaF₂ on the reduction roasting and magnetic separation of high-phosphorus iron ore containing phosphorus in the form of Fe₃PO₇ and apatite was investigated. The results revealed that Na₂CO₃ had the most significant effect on iron recovery and dephosphorization, followed by CaCO₃, the effect of CaF₂ was negligible. The mechanisms of CaCO₃, Na₂CO₃, and CaF₂ were investigated using X-ray diffraction (XRD), scanning electron microscopy and energy dispersive spectrometry (SEM–EDS). Without additives, Fe₃PO₇ was reduced to elemental phosphorus and formed an iron–phosphorus alloy with metallic iron. The addition of CaCO₃ reacted with Fe₃PO₇ to generate an enormous amount of Ca₃(PO₄)₂ and promoted the reduction of iron oxides. However, the growth of iron particles was inhibited. With the addition of Na₂CO₃, the phosphorus in Fe₃PO₇ migrated to nepheline and Na₂CO₃ improved the reduction of iron oxides and growth of iron particles. Therefore, the recovery of iron and the separation of iron and phosphorus were the best. In contrast, CaF₂ reacted with Fe₃PO₇ to form fine Ca₃(PO₄)₂ particles scattered around the iron particles, making the separation of iron and phosphorus difficult.     

不同硅饱和系数水榴石的碳酸化分解动力学

Carbonated decomposition of hydrogarnet is one of the vital reactions of the calcification–carbonation method, which is designed to dispose of low-grade bauxite and Bayer red mud and is a novel eco-friendly method. In this study, the effect of the silica saturation coefficient (x) on the carbonation of hydrogarnet was investigated from the kinetic perspective. The results indicated that the carbonation of hydrogarnets with different x values (x = 0.27, 0.36, 0.70, and 0.73) underwent two stages with significantly different rates, and the kinetic mechanisms of the two stages can be described by the kinetic functions R3 and D3. The apparent activation energies at Stages 1 and 2 were 41.96–81.64 and 14.80–34.84 kJ/mol, respectively. Moreover, the corresponding limiting steps of the two stages were interfacial chemical reaction and diffusion.     

一种超重力燃烧合成制备高性能高熵合金的新方法

A new method of high-gravity combustion synthesis (HGCS) followed by post-treatment (PT) is reported for preparing high-performance high-entropy alloys (HEAs), Cr_0.9FeNi_2.5V_0.2Al_0.5 alloy, whereby cheap thermite powder is used as the raw material. In this process, the HEA melt and the ceramic melt are rapidly formed by a strong exothermic combustion synthesis reaction and completely separated under a high-gravity field. Then, the master alloy is obtained after cooling. Subsequently, the master alloy is sequentially subjected to conventional vacuum arc melting (VAM), homogenization treatment, cold rolling, and annealing treatment to realize a tensile strength, yield strength, and elongation of 1250 MPa, 1075 MPa, and 2.9%, respectively. The present method is increasingly attractive due to its low cost of raw materials and the intermediate product obtained without high-temperature heating. Based on the calculation of phase separation kinetics in the high-temperature melt, it is expected that the final alloys with high performance can be prepared directly across master alloys with higher high-gravity coefficients.     

窄板坯结晶器内连铸工艺参数对钢液流场的影响

Computational simulations and high-temperature measurements of velocities near the surface of a mold were carried out by using the rod deflection method to study the effects of various operating parameters on the flow field in slab continuous casting (CC) molds with narrow widths for the production of automobile exposed panels. Reasonable agreement between the calculated results and measured subsurface velocities of liquid steel was obtained under different operating parameters of the CC process. The simulation results reveal that the flow field in the horizontal plane located 50 mm from the meniscus can be used as the characteristic flow field to optimize the flow field of molten steel in the mold. Increases in casting speed can increase the subsurface velocity of molten steel and shift the position of the vortex core downward in the downward circulation zone. The flow field of liquid steel in a 1040 mm-wide slab CC mold can be improved by an Ar gas flow rate of 7 L·min?1 and casting speed of 1.7 m·min?1. Under the present experimental conditions, the double-roll flow pattern is generally stable at a submerged entry nozzle immersion depth of 170 mm.     

电渣重熔脱硫技术研究进展

Electroslag remelting (ESR) gives a combination of liquid metal refining and solidification structure control. One of the typical aspects of liquid metal refining during ESR for the advanced steel and alloy production is desulfurization. It involves two patterns, i.e., slag–metal reaction and gas–slag reaction (gasifying desulfurization). In this paper, the advances in desulfurization practices of ESR are reviewed. The effects of processing parameters, including the initial sulfur level of consumable electrode, remelting atmosphere, deoxidation schemes of ESR, slag composition, melting rate, and electrical parameters on the desulfurization in ESR are assessed. The interrelation between desulfurization and sulfide inclusion evolution during ESR is discussed, and advancements in the production of sulfur-bearing steel at a high-sulfur level during ESR are described. The remaining challenges for future work are also proposed.     

利用皮秒激光烧蚀制备非球形铝纳米颗粒

We report the picosecond laser ablation of aluminum targets immersed in a polar organic liquid (chloroform, CHCl₃) with ~2 ps laser pulses at an input energy of ~350 μJ. The synthesized aluminum nanoparticles exhibited a surface plasmon resonance peak at ~340 nm. Scanning electron microscopy images of Al nanoparticles demonstrated the spherical morphology with an average size of (27 ± 3.6) nm. The formation of smaller spherical Al nanoparticles and the diminished growth could be from the formation of electric double layers on the Al nanoparticles. In addition to spherical aluminum nanoparticles, triangular/pentagonal/hexagonal nanoparticles were also observed in the colloidal solution. Field emission scanning electron microscopy images of ablated Al targets demonstrated laser induced periodic surface structures (LIPSSs), which were the high spatial frequency LIPSSs (HSF-LIPSSs) since their grating period was ~280 nm. Additionally, coarse structures with a period of ~700 nm were observed.     

Mineral transition and formation mechanism of calcium aluminate compounds in CaO?Al2O3?Na2O system during high-temperature sintering

The mineral transition and formation mechanism of calcium aluminate compounds in CaO?Al₂O₃?Na₂O system during the high-temperature sintering process were systematically investigated using DSC?TG, XRD, SEM?EDS, FTIR, and Raman spectra, and the crystal structure of Na₄Ca₃(AlO₂)₁₀ was also simulated by Material Studio software. The results indicated that the minerals formed during the sintering process included Na₄Ca₃(AlO₂)₁₀, CaO·Al₂O₃, and 12CaO·7Al₂O₃, and the content of Na₄Ca₃(AlO₂)₁₀ could reach 92wt% when sintered at 1200°C for 30 min. The main formation stage of Na₄Ca₃(AlO₂)₁₀ occurred at temperatures from 970 to 1100°C, and the content could reach 82wt% when the reaction temperature increased to 1100°C. The crystal system of Na₄Ca₃(AlO₂)₁₀ was tetragonal, and the cells preferred to grow along crystal planes (110) and (210). The formation of Na₄Ca₃(AlO₂)₁₀ was an exothermic reaction that followed a secondary reaction model, and its activation energy was 223.97 kJ/mol.     

含细夹层的分矿充填层中流动特性的可视化

Ore particles, especially fine interlayers, commonly segregate in heap stacking, leading to undesirable flow paths and changeable flow velocity fields of packed beds. Computed tomography (CT), COMSOL Multiphysics, and MATLAB were utilized to quantify pore structures and visualize flow behavior inside packed beds with segregated fine interlayers. The formation of fine interlayers was accompanied with the segregation of particles in packed beds. Fine particles reached the upper position of the packed beds during stacking. CT revealed that the average porosity of fine interlayers (24.21%) was significantly lower than that of the heap packed by coarse ores (37.42%), which directly affected the formation of flow paths. Specifically, the potential flow paths in the internal regions of fine interlayers were undeveloped. Fluid flowed and bypassed the fine interlayers and along the sides of the packed beds. Flow velocity also indicated that the flow paths easily gathered in the pore throat where flow velocity (1.8 × 10?5 m/s) suddenly increased. Fluid stagnant regions with a flow velocity lower than 0.2 × 10?5 m/s appeared in flow paths with a large diameter.     

方向关系与距离关系的定性描述与推理

由于空间问题固有的复杂性和不确定性 ,空间关系的描述和推理普遍采用定性的方法 .方向关系和距离关系是两类重要的空间关系 ,用以确定空间目标的方位 .当前方向和距离关系分别使用各自独立的描述推理模型 ,限制了推理的准确度 .而人们对空间目标方位的确定通常是同时考虑目标的方向和距离 .在形式化定性描述方向关系和距离关系推理的基础上 ,将方向关系和距离关系的推理结合起来 ,形成方向关系和距离关系的集成组合运算 ,方向和距离关系相互限制 ,能够进一步准确推断目标的方位 .最后 ,以实例说明方向关系和距离关系的集成组合运算将提高空间目标方位推断的准确度 .     

模糊论在ICAI中的应用

作者根据ICAI中存在大量模糊性问题这一事实,对模糊论在ICAI中的应用进行了研究.讨论了用模糊命题、模糊关系、模糊产生式表示模糊知识的方法和运用模糊逻辑、蕴含网络、模糊规划进行模糊推理的技术以及根据模糊统计进行模糊决策等问题.     

重演律的哲学探索

系统阐释"三大重演律"和三个推论,探索了重演律中的偶然和必然、个别和一般、对称与破缺、内环境与外环境等哲学问题,建立重演律方法论,特别是重演方法在模型与模拟、教学法以及文学艺术中的广泛应用的方法,利用重演方法阐明科学、文化、经济加速发展的机制与原理,以及落后国家、落后民族在较短时间赶上先进国家和先进民族的内在机理。     

论审判活动中的法律假言推理

法律假言推理是诉讼活动中的重要推理，分析和探讨审判活动中法律假言推理的特征及其结构形式，旨在阐明为了获得可靠，准确的审判结论；除了要具备相关的法律知识以外，还需具备法律逻辑的基础知识，在逻辑的层面上来理解和把握法律规定，进行有效的法律推理，力审判结论提供思维保证。     

模糊缺省推理的理论和方法研究

在一种含有补余律的模糊抽象代数系统（即ＦｕｚｚｙＢｏｏｌｅ代数）上，利用模糊逻辑公式与布尔函数的相互转换性，构造了具有模糊非单调推理能力的推理机制；从可应用性出发对模糊缺省规则进行了深入的讨论。该推理机制不仅增加了在量的描述方面的知识表达能力，而且在一定程度上解决了扩张存在性问题，提高了推理的效率。     

简化模糊推论模型与多层构造模糊推论模型的对比研究

能够直接输出非模糊值的简化模糊推论已被广泛应用于控制系统.随着条件部成员函数个数的增加,这种模糊推论模型能够获得较高的输出精度.但是,对于采用从现实环境下获取的示教数据进行模型学习的情况,简化模糊推论模型有时难以获得很高的辨识精度.本文采用现实环境下的两种典型的示教数据,对单层构造的模糊推论模型和多层构造的模糊推论模型进行辨识.实验结果表明,多层构造的模糊推论模型比单层构造的模糊推论模型具有更高的辨识精度和对示教数据的适应能力.图7,表4,参16.     

不确定性推理及其在斜坡类地质灾害危险性区划中的应用

通过对不确定性推理方法尤其是概率推理方法的研究,将其引入到斜坡类地质灾害危险性区划之中。在对不确定因子法、主观贝叶斯法、贝叶斯网络法和影响图法等4种不确定性推理方法进行原理分析的基础上,分别给出了其在斜坡类地质灾害危险性区划中的应用思路,并在辽宁省鞍山市岫岩县进行了试验,进而总结形成了一套基于不确定性推理开展斜坡类地质灾害危险性区划的方法体系,实现了对传统区划方法的改进。     

假言推理研究的进程与展望

假言推理是前提中有一个为假言命题,并且根据假言命题前件与后件之间的关系而推出结论的推理。假言推理研究的进程大致可分为两个阶段：第一阶段是从20世纪60年代至70年代末——问题提出阶段,第二阶段是从80年代初至现在——理论发展阶段。纵观假官推理研究的进程,可以发现以往的研究存在着一些缺陷或不足,这是今后关于假言推理研究应该着重关注和解决的问题。     

先验概率值的一种学习方法

近年来,已提出了一些非确定性信息的理论,如概率理论,证据理论,可能性理论,基于Ｂａｙｅｓｉａｎ公式的似然推理模型等。这些方法均在不同程度上要求专家给出一些先验概率值,从而影响了它们的应用程度。所以,建立一种有效的获取先验概率值的方法是有必要的。本文给出一种从实际例子中自动获取先验概率值的方法。     

空间推理研究的方法学

概述了空间推理研究的内容,关键问题的基本方法,从基本原则,形式框架,研究步骤,表示体系和推理框架等五个方面提出了空间推理研究的方法学,结合实际研究案例阐述了该方法的合理性与有效性。最后指出了空间推理研究的进一步工作和方向。