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.     

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.     

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.     

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.     

做弘扬先进文化的促进派

该文以江泽民总书记“三个代表”的讲话为指导,具体阐述了代表中国当代先进文化的前进方向是坚持党的先进性的必然要求这一论题。     

"邓小平理论热":校园高雅文化的理性选择

近些年来在校园高雅文化活动中,"邓小平理论学习热"引人注目,体现出强烈的高雅性与平俗性、广博性与专业性、创新性与务实性的融合效应.它是改革开放的社会大文化氛围、大学生自身社会实践和邓小平"三进"工作的综合产物.高校要因势利导,把"邓小平理论热"引向理论文化育人的新高度,适应新世纪新要求,切实提高青年学生的文化力、创新力和综合力,发挥理论文化在人才培养中的独到作用.     

邓小平的人才学说对高校人事管理工作的启示

邓小平理论宝库中，有关人才的发现、选拔、培养、使用、开发和人事管理等的一系列论述，已成为指导我国高校人事管理的科学理论依据。遵照邓小平同志的有关教导，高校组织人事部门应牢固树立“尊重知识、尊重人才”的观念，把选好、用好人才，努力做到“人尽其才，才尽其用”作为高校人事管理工作的理想目标，把改革旧的人事管理体制作为高校人事管理工作的关键来抓。     

邓小平的民族统一战线思想

通过对邓小平统一战线思想的深刻分析，指出其是建设有中国特色社会主义理论科学体系的重要组成部分，是毛泽东统一战线思想发展的新阶段。科学地回答和解决了新时期统一战线的新课题和新任务。     

关于《中图法》中邓小平理论的立类研究

本文论述了在《中图法》Ａ大类中增设邓小平理论类目的前提,说明了在Ａ大类中增设邓小平理论类目的理由,探讨了邓小平理论在《中图法》中立类和归类的方法。     

邓小平社会结构理论探析

社会结构问题是马克思主义所特别关注的一个极为重要的问题。邓小平坚持从实际出发，创造性地运用马克思主义社会结构的思想，多层次、多视角地分析我国社会主义初级阶段的社会结构状况，并提出了许多关于解决当代中国社会结构问题的精辟见解，形成了独具特色的社会主义社会结构理论。解放生产力和发展生产力是邓小平社会结构理论的核心内容，优化中国社会主义的社会结构是邓小平社会结构理论的现实出发点和着眼点。学习和研究邓小平社会结构理论具有重要的理论意义和现实意义．     

解读邓小平关于民族发展的思想

邓小平民族理论是邓小平理论的重要组成部分,其中的核心内容是关于民族发展的理论。论述了邓小平民族理论的形成和主要特点,着重阐述了邓小平关于民族发展的思想:观察少数民族地区主要是看那个地区能不能发展起来;国家帮助少数民族发展的政策是坚定不移的;改革开放是各民族发展的必由之路;共同富裕和“两个大局”的战略构想。     

邓小平外交思想研究综论

邓小平外交思想是邓小平理论的重要组成部分,是当代中国外交工作的指导思想,它是对中国的现状和当今世界各种矛盾分析的产物,是实事求是原则在外交领域的有效延伸,是维护中国国家权益的生动表现。本文从邓小平外交思想的精神内涵、主要内容、重要特色和现实意义四个方面,综合探讨了邓小平同志的外交思想。     

邓小平民主思想研究——作为手段的民主与作为目的的民主

邓小平民主思想是作为手段的民主与作为目的的民主并存的民主思想,他抓住了政治建设的首要任务是为经济建设也即为民生建设保驾护航这一历史规律。从世界各国的经验教训来看,脱离了经济建设,追求形式的和以西方为模式的民主建设,不仅实现不了真正的民主,反而带来的是国家的混乱和民主政治的不可能。作为目的的民主思想又从根本上解决了社会主义民主与资本主义民主的区别,为我国的民主政治建设指明了方向,开拓了民主的内涵和实质,具有很强的现实指导意义。     

邓小平行政体制改革思想及其现实指导意义

邓小平行政体制改革思想具有丰富的内涵及现实指导意义.他设计了中国特色行政体制的基本架构,为当今行政体制改革奠定了基础;确立了行政体制改革的价值取向,为后来的行政体制改革指明了方向;采用了"循序渐进"的行政改革方式,为新时代行政体制改革提供了蓝本;树立了政府职能转变的改革核心观,为历次行政体制改革的根本任务做出了规定.