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.     

高校体育教学中开展救护教育的必要性与实施途径研究——基于生命教育的视角

运用文献资料法和逻辑分析法等方法,从生命教育的视角对高校体育课教学中开展救护技能教育的必要性和实施途径进行研究。认为:生命教育是教育的前提,而基本的生命救护知识是生命教育的重要组成部分。体育课堂教学是实施救护教育的最佳途径。可通过加强宣传、救护知识进课程、理论与实践相结合的教学形式、加强教师专业知识培训等途径来实施救护教学,以期为我国高校的救护教育起到推广作用。     

基础教育课程改革对高师教学改革的挑战

在新一轮基础教育课程改革中,教学观念、教师角色、学习方式等的变化对高师教学改革提出了严峻挑战.加强高师教学内容、教学方法、教学手段和教学评价改革,是高师教育自身发展的需要,也是实施素质教育、发展基础教育的重要使命.     

深入研究人文教育的本质与规律,构建全方位高校人文教育体系

人文教育的实质是人性教育,核心是涵养人文精神,特征表现为价值理性。人文教育规律表现为：教学过程的引导性;学习过程的探索性;学习方法的内省性、体验性;实践活动的必要性;教育形式的多样性。要提高人文教育的效果,必须精选教学内容,激发学生的学习兴趣,培育具有人文精神和素质的教师队伍,构建＂一个渠道,两方渗透,三项活动,四种氛围＂的全方位人文教育体系。     

论素质教育与高校体育俱乐部制

在高校体育教学中实行体育俱乐部制，使素质教育深入到了体育教育中，是使有共同爱好、兴趣、目标的学生共同完成体育教学任务的一种教学模式。它迎合了素质教育尊重学生人格，承认学生的个性差异，重视学生的个性发展，培养了学生的创造能力，改变了以前的“传习式”教学模式，使得学生能够主动地、生动活泼地进行学习。     

论大众化教育阶段的高校教学管理工作

高等学校的教学管理工作必须适应高等学校发展的要求.我国高等教育在从精英向大众高等教育的转变过程中,教学管理工作必须进行相应的改革.论述了高校教学管理工作的特点,对大众化教育阶段如何做好教学管理工作进行了初步的探讨.     

《学记》的教育思想及其现代诠释

《学记》是中国古代一部专门阐释教育、教学问题的论著,它总结了我国先秦时期儒家教育和教学方面的经验和理论,其包含“建国君民”、“化民成俗”的教育理念,“教学相长”、“善教善学”的教育方法,“豫时孙摩”、“长善救失”的教学原则等.这些教育理念、教育方法以及教学原则启发当下教育要坚持以人为本,培育和提升教师及学生的素质;树立现代教育理念,改革课程设置;创新教育方法,改变传统的教育模式.     

多媒体教学在医学教育桥梁性课程的应用与思考

文章结合西藏高等医学教育的实际情况,指出多媒体教学方法在医学教育桥梁性课程中所起的积极作用,并对教学过程中应注意的问题进行了总结和分析,为提高医学教育桥梁性课程的教学质量提供了理论依据。     

思想政治教育中信仰教育弱化问题研究

目前高校的信仰教育弱化问题主要表现为：信仰教育的客体对信仰教育的认识模糊、态度淡漠、主流信仰状况不容乐观，信仰教育主体的意识不强，信仰教育的内部机制不协调等；信仰教育弱化问题的成因，主要归结为社会大环境等宏观因素，以往信仰教育的误区以及评价体系等中观因素，大学生群体的身心特点等微观因素；解决信仰教育弱化问题主要从提高对信仰教育的认识，把握信仰教育的特点和规律，创新信仰教育的原则和方法做起。     

理科学科德育简论

由教学的教育性原则引出学科德育的概念,由中央与教育部的相关文件得出实施学科德育的必要性,给出了理科学科德育的界定,总结数学学科德育的理论研究与教学实践,指出数学学科德育的实施与若干发达国家的德育做法的相似性,简要探讨了理科学科德育.     

体校体育教学中的德育教育研究

德育是教育的重要组成部分,在现代教育中,教育界的同仁越来越认识到德育教育在学校教育工作中的重要性,本文以体育教学中渗透德育素质教育为切入点进行研究,分析体校学生德育素质培养的重要性和影响因素,通过对多年的教学经验的总结,提出在体校体育教育中渗透德育的可行方法。