烧结铁矿中FeO含量对其在富氢高炉中还原行为的影响

Japan started the national project “COURSE 50” for CO₂ reduction in the 2000s. This project aimed to establish novel technologies to reduce CO₂ emissions with partially utilization of hydrogen in blast furnace-based ironmaking by 30% by around 2030 and use it for practical applications by 2050. The idea is that instead of coke, hydrogen is used as the reducing agent, leading to lower fossil fuel consumption in the process. It has been reported that the reduction behavior of hematite, magnetite, calcium ferrite, and slag in the sinter is different, and it is also considerably influenced by the sinter morphology. This study aimed to investigate the reduction behavior of sinters in hydrogen enriched blast furnace with different mineral morphologies in CO–CO₂–H₂ mixed gas. As an experimental sample, two sinter samples with significantly different hematite and magnetite ratios were prepared to compare their reduction behaviors. The reduction of wustite to iron was carried out at 1000, 900, and 800°C in a CO–CO₂–H₂ atmosphere for the mineral morphology-controlled sinter, and the following findings were obtained. The reduction rate of smaller amount of FeO led to faster increase of the reduction rate curve at the initial stage of reduction. Macro-observations of reduced samples showed that the reaction proceeded from the outer periphery of the sample toward the inside, and a reaction interface was observed where reduced iron and wustite coexisted. Micro-observations revealed three layers, namely, wustite single phase in the center zone of the sample, iron single phase in the outer periphery zone of the sample, and iron oxide-derived wustite FeO and iron, or calcium ferrite-derived wustite 'FeO' and iron in the reaction interface zone. A two-interface unreacted core model was successfully applied for the kinetic analysis of the reduction reaction, and obtained temperature dependent expressions of the chemical reaction coefficients from each mineral phases.     

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.     

Mg和La对Ca–Ti 处理钢中夹杂物演变和组织的影响

The evolution of inclusions and the formation of acicular ferrite (AF) in Ca–Ti treated steel was systematically investigated after Mg and La addition. The inclusions in the molten steel were Ca–Al–O, Ca–Al–Mg–O, and La–Mg–Ca–Al–O after Ca, Mg, and La addition, respectively. The type of oxide inclusion in the final quenched samples was the same as that in the molten steel. However, unlike those in molten steel, the inclusions were Ca–Al–Ti–O + MnS, Ca–Mg–Al–Ti–O + MnS, and La–Ca–Mg–Al–Ti–O + MnS in Mg-free, Mg-containing, and La-containing samples, respectively. The inclusions distributed dispersedly in the La-containing sample. In addition, the average size of the inclusions in the La-containing sample was the smallest, while the number density of inclusions was the highest. The size of effective inclusions (nucleus of AF formation) was mainly in the range of 1–3 μm. In addition, the content of ferrite side plates (FSP) decreased, while the percentage of AF increased by 16.2% due to the increase in the number of effective inclusions in the La-containing sample in this study.     

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.     

高校教师科研倦怠的特征及原因探析

以高校教师科研倦怠为研究对象,分析了倦怠的概念和应用领域,提出了科研倦怠的概念,论述了科研倦怠的表现形式,从个体特征、高校科研条件与氛围、社会因素三个方面阐述了导致科研倦怠的原因,提出了缓解或改善科研倦怠的建议。     

我国运动心理学研究的发展状况与分析

以近五届全国运动心理学学术会议摘录的534篇论文作为文献资料,从研究领域、研究方法、研究对象、研究人员等几个方面分析摘录论文的特点,结果表明：我国运动心理学的研究领域不断拓宽;研究方法以实证主义为主流,注重量的研究;研究对象不断丰富;研究人员构成丰富,但各类研究力量相差悬殊且研究主题各有侧重;大学教师研究人员队伍呈现扩张之势,逐渐成为推动我国运动心理学快速发展的主导力量。     

新世纪生活质量研究的进展和趋势

新世纪生活质量的研究进一步深入，研究视角不断拓展，研究层面不断增多。本文从生活质量的概念、指标体系构建、研究特点、研究展望等方面，对新世纪以来国内外生活质量研究状况做一综述。     

生物多样性研究发展态势与挑战

在文献调研、专家咨询和文献计量分析的基础上,对国际生物多样性研究的发展历程进行了回顾,分析了国际生物多样性研究的发展态势和挑战。分析结果表明,国际生物多样性研究热点主要集中在植物多样性开发、生态保护、物种丰度、基因多样性、可持续管理、气候变化、森林、土壤、生态系统等方面,并面临以下新的形势与挑战：（1）生物多样性科学已成为联系生物学各学科以及相关科学领域的综合交叉研究领域;（2）人类社会与生物多样性的交互关系是生物多样性研究的核心内容;（3）观测监测网络成为国际生物多样性研究的关键平台;（4）长期、持续和更广泛范围的生物多样性调查和监测成为重要的工作方向;（5）先进技术成为生物多样性研究和保护的重要手段;（6）生物多样性评估工作正成为生物多样性可持续利用的基础性工作。最后,根据国际研究进展与特点提出了加强我国生物多样性研究的建议。     

国外废弃矿区工业遗产旅游研究进展

 以Web of Science收录的国外工业遗产旅游的文献为基础,对相关的499篇文献进行综述,梳理与归纳出废弃矿区工业遗产旅游的研究趋势、研究热点和研究方法,并从工业遗产旅游的概念内涵、旅游开发潜力的评价、旅游影响、旅游目的地的构建与开发商业模式、旅游者与旅游体验和社区居民管理6个方面阐明国外关于废弃矿区工业遗产旅游研究的主要内容。结果表明,国外工业遗产旅游研究以应用为导向,研究热度不断上升,但研究数量有限,未来研究增长潜力巨大。结合国外的研究经验,中国未来研究重点应放在完善工业遗产旅游理论体系、推进分步骤开发潜力评价框架的构建、加强工业遗产旅游综合影响的研究、加强旅游者消费行为规律的研究、深入开展社区居民管理的研究、推动工业遗产旅游研究方法创新研究等方面。     

我国体育教师教育研究的知识图谱分析

运用文献法、数理统计法、逻辑分析法、文献计量分析等方法对2000-2016年中国期刊网络出版总库(CNKI)所收录的99篇体育教师教育相关的中文核心期刊论文进行分析.研究结果显示:我国体育教师教育研究成果数量呈现出波浪式上升趋势;黄爱峰、季浏、王健、吴昊、李芳等为体育教师教育研究核心作者的主题构成.体育教师教育研究的机构以高校为主,师范院校和专业体育院校是体育教师教育研究的中坚力量.各研究机构与作者之间形成了小型合作研究网络,但合作研究程度较低.我国体育教师教育研究的热点领域集中在体育教师教育深化改革方面的研究、中外体育教师教育的对比研究、体育教师教育专业化发展途径研究和体育教师教育现状研究.     

论虚拟物流研究及其发展

虚拟物流理论研究是物流管理研究中的前沿课题.在对现有诸多不统一的虚拟物流、虚拟物流企业概念分析的基础上,详细阐述了虚拟物流和虚拟物流组织的内涵,介绍了目前国内外有关虚拟物流的研究现状,并在此基础上提出了虚拟物流的理论研究三维框架,给出了虚拟物流理论研究的主要内容,指出了虚拟物流研究的四个发展方向以及相应的研究重点.     

非真实感绘制技术研究

自20世纪90年代中期开始,非真实感绘制逐渐成为计算机图形学的研究热点之一.本文从非真实感绘制技术的形成和发展出发,详细论述了非真实感绘制的特点、分类、及应用.并介绍了非真实感的主要绘制技术,分析了每种绘制技术的具体算法.在此基础上探讨了非真实感绘制技术现存在的难点以及未来的发展趋势.     

体系视野下的MBSE

 综述了基于模型体系工程的研究进展及应用情况，分析了其未来发展需求。从体系架构建模和体系工程流程建模两个方面，介绍了当前基于模型体系工程的研究、应用方面技术主流。以智能化无人作战为应用背景，提出了一个多集群智能体系工程研究框架，并在该框架下分析了基于模型体系工程的研究需求，从体系和集群两个层面提出了MBSE的研究设想和发展策略。     

2003—2013年维普期刊网收录体育旅游资源相关文献分析

为了清晰地了解体育旅游资源相关研究的现状,统计分析了2003—2013年维普期刊数据库收录的相关文献.结果显示:从2003—2007年,关于体育旅游资源的研究呈逐年上升趋势,从2007年至今研究相对稳定,研究内容主要包含3个方面,即开发研究、相关概念、区域特征.研究存在的主要问题有:①不同内容的研究比例不协调,基础性概念和理论研究较少;②在开发研究中,有关体育与旅游关系、各相关部门的工作及旅游者的行为特征的研究较缺乏等.