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.     

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.     

氧化锌矿物浸出渣中铅、锶的提取及动力学分析

NH₄HCO₃ conversion followed by HCl leaching was performed and proven to be effective in extracting Pb and Sr from zinc extracted residual. The mechanism and operating conditions of NH₄HCO₃ conversion, including molar ratio of NH₄HCO₃ to zinc extracted residual, NH₄HCO₃ concentration, conversion temperature, conversion time, and stirring velocity, were discussed, and operating conditions were optimized by the orthogonal test. Experimental results indicate that NH₄HCO₃ conversion at temperatures ranging from 25 to 85°C follows the shrinking unreacted core model and is controlled by inner diffusion through the product layer. The extraction ratios of Pb and Sr under optimized conditions reached 85.15% and 87.08%, respectively. Moreover, the apparent activation energies of Pb and Sr were 13.85 and 13.67 kJ·mol?1, respectively.     

摩擦焊接碳钢（EN24）和镍基高温合金（IN718）的显微组织和力学性能

Continuous-drive rotary friction welding was performed to join cylindrical specimens of carbon steel (EN24) and nickel-based superalloy (IN718), and the microstructures of three distinct weld zones—the weld interface (WI)/thermo-mechanically affected zone (TMAZ), the heat-affected zone (HAZ), and the base metal—were examined. The joint was observed to be free of defects but featured uneven flash formation. Electron backscatter diffraction (EBSD) analysis showed substantial changes in high-angle grain boundaries, low-angle grain boundaries, and twin boundaries in the TMAZ and HAZ. Moreover, significant refinement in grain size (2–5 μm) was observed at the WI/TMAZ with reference to the base metal. The possible causes of these are discussed. The microhardness profile across the welded joint shows variation in hardness. The changes in hardness are ascribed to grain refinement, phase transformation, and the dissolution of strengthening precipitates. The tensile test results reveal that a joint efficiency of 100% can be achieved using this method.     

汽车暴露面板带有表面条状缺陷的夹杂物分布特征分析:一种定量电解方法

The specific distribution characteristics of inclusions along with the sliver defect were analyzed in detail to explain the formation mechanism of the sliver defect on the automobile exposed panel surface. A quantitative electrolysis method was used to compare and evaluate the three-dimensional morphology, size, composition, quantity, and distribution of inclusions in the defect and non-defect zone of automobile exposed panel. The Al₂O₃ inclusions were observed to be aggregated or chain-like shape along with the sliver defect of about 3–10 μm. The aggregation sections of the Al₂O₃ inclusions are distributed discretely along the rolling direction, with a spacing of 3–7 mm, a length of 6–7 mm, and a width of about 3 mm. The inclusion area part is 0.04%–0.16% with an average value of 0.08%, the inclusion number density is 40 mm?2 and the inclusion average spacing is 25.13 μm. The inclusion spacing is approximately 40–160 μm, with an average value of 68.76 μm in chain-like inclusion parts. The average area fraction and number density of inclusions in the non-defect region were reduced to about 0.002% and 1–2 mm?2, respectively, with the inclusion spacing of 400 μm and the size of Al₂O₃ being 1–3 μm.     

在酸性溶液中加压氧化三价砷离子和二价铁离子

The co-oxidation of As(III) and Fe(II) in acidic solutions by pressured oxygen was studied under an oxygen pressure between 0.5 and 2.0 MPa at a temperature of 150°C. It was confirmed that without Fe(II) ions, As(III) ions in the solutions are virtually non-oxidizable by pressured oxygen even at a temperature as high as 200°C and an oxygen pressure up to 2.0 MPa. Fe(II) ions in the solutions did have a catalysis effect on the oxidation of As(III), possibly attributable to the production of such strong oxidants as hydroxyl free radicals (OH·) and Fe(IV) in the oxidation process of Fe(II). The effects of such factors as the initial molar ratio of Fe(II)/As(III), initial pH value of the solution, oxygen pressure, and the addition of radical scavengers on the oxidation efficiencies of As(III) and Fe(II) were studied. It was found that the oxidation of As(III) was limited in the co-oxidation process due to the accumulation of the As(III) oxidation product, As(V), in the solutions.     

采用超声组装与滚压工艺制备铝–碳纳米管复合材料

This study introduced a novel fabrication of aluminum–carbon nanotube (CNT) composites by employing bulk acoustic waves and accumulative roll bonding (ARB). In this method, CNT particles were aligned using ultrasonic standing wave in an aqueous media, and the arrayed particles were precipitated on the aluminum plate substrate. Then, the plates rolled on each other through the ARB process with four passes. Optical and scanning electron micrographs demonstrated the effective aligning of CNTs on the aluminum substrate with a negligible deviation of arrayed CNTs through the ARB process. The X-ray diffraction pattern of the developed composites showed no peaks for carbon and aluminum carbide. In addition, tensile tests showed that the longitudinal strength of the specimens processed with aligned CNTs was significantly greater than that of the specimens with common randomly dispersed particles. The proposed technique is beneficial for the fabrication of Al–CNT composites with directional mechanical strength.     

活化天然矿石选择性还原二氧化碳为无定形碳

Natural magnetite formed by the isomorphism substitutions of transition metals, including Fe, Ti, Co, etc., was activated by mechanical grinding followed by H₂ reduction. The temperature-programmed reduction of hydrogen (H₂-TPR) and temperature-programmed surface reaction of carbon dioxide (CO₂-TPSR) were carried out to investigate the processes of oxygen loss and CO₂ reduction. The samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy (EDS). The results showed that the stability of spinel phases and oxygen-deficient degree significantly increased after natural magnetite was mechanically milled and reduced in H₂ atmosphere. Meanwhile, the activity and selectivity of CO₂ reduction into carbon were enhanced. The deposited carbon on the activated natural magnetite was confirmed as amorphous. The amount of carbon after CO₂ reduction at 300°C for 90 min over the activated natural magnetite was 2.87wt% higher than that over the natural magnetite.     

价值与事实的二维分野及其两个运用

本文分析哲学意义上价值与事实之间的关系以及由其演变的理性主义与经验主义,论述了这一研究分析方法在政治学上与经济学上的应用,指出学科之间的联系,试图拓宽学术研究的视野。     

软硬酸碱规则及其软硬度的计算

本文在介绍其它计算酸碱软硬度方法的基础上,提出一个新的计算广义碱的软硬度的公式,所得结果与其它方法大致相同,且大大增多了所能计算的碱的数目     

高校科技资源转化创新的问题与对策

科技资源是"第一资源",它是科技创新活动的基础,对提升自主创新能力和建设创新型国家发挥着基础性作用。高校科技资源的转化创新是高校参与科技创新的重要基础。在对高校科技资源内涵、特点及重要性进行分析基础上,提出高校科技资源产学研间联动不足、与经济融合不够、布局分散、投入方式较为单一等问题,并提出了相应的对策和建议。     

2013年度天津市区县科技进步综合能力比较研究

区县科技进步是地区科技进步的基石,是提高地区整体实力和竞争力的基础。通过对区县科技进步状况开展监测评价,有利于量化分析各区县科技进步综合能力和差异,巩固优势,发现不足,对进一步提升区域综合科技竞争力具有重要意义。对2013年度天津市区县科技进步统计监测评价结果进行分析,针对所发现问题提出了相应的对策建议。     

高校招投标采购的特点

随着高校向现代化教育技术的发展,购买仪器采购数量的增多,尤其是进口设备的采购,对现有的采购程序提出了新的挑战。文中从高校设备购置的特点出发,讨论了市场与竞争、如何选择采购方式、验收的重要意义以及在全过程的监督机制等问题。通过在实际中遇到的各种问题,提出了应该加强政府采购制度建设,改善市场竞争环境,强化设备采购前期调研工作,合理选择设备采购方式等。总结了高校仪器设备招标采购的经验,探讨了高校仪器设备招标采购的规律。     

持续深化科技体制改革,更好激发科技人员的积极性和创造性

 基于政策文本分析和文献资料研究，梳理了1978年以来激发科技人员积极性创造性改革相关政策，简述了2016年以来有关方面的主要改革行动。通过对中国科协第3次全国科技工作者状况调查（2013年）、第4次全国科技工作者状况调查（2017年）相关数据的比较分析发现，激发科技人员积极性创造性改革已取得阶段性成效，科技工作者对激发科技人员积极性创造性改革相关问题的评价明显提高。     

中国科技伦理治理体系建设进展

 以国家科技伦理委员会成立、《关于加强科技伦理治理的意见》 出台为标志， 中国科技伦理治理体系拉开新帷幕。回顾了现代科技伦理议题的兴起与发展历程， 结合中国科技伦理治理体系建设状况与中国科协相关调研成果， 通过分析政策执行、 主体责任、 科技工作者伦理素养等几类突出议题， 解读了新时代中国科技伦理治理体系建设的方针与主要原则。认为中国面向未来的科技伦理治理是以促进向善、 负责任的科技发展为目标， 推动形成多方共治、 共同担责的科技伦理治理图景。     

论中小学教师的人文素养及其拓展与提升

通过追溯分析,论述了导致现有教师人文素养欠缺的时代背景和社会因素。从教师人文素养的内涵及人文素养的基础性、发展性和延伸性三个层次中的诸要素出发,围绕我国中小学校教师现阶段的人文素养情况,给出拓展和提升教师人文素养的途径、方式和方法。     

数学在现代科学技术体系中的地位和作用

分析了数学在现代科学技术体系中的重要作用,说明了数学发展过程中存在的问题和面临的机遇和挑战。     

袁宗道:"稳实"掩盖的自适精神 --公安派人格心态研究之一

晚明公安派的全面定性在作为“三袁”之长的袁宗道手中业已完成。在袁宗道“稳实”面目掩盖下的强烈自适精神正是公安一派群体人格心态的鲜明特征，也正是公安派的基本“定性”之一。性情自适潜在着个体与社会、感性与理性之间难以调和的冲突，二相反相成而存在于个体内在精神结构，它们之间的对立互动不时激荡着自适主体的脆弱心灵，既予之以自适的渴望与欢乐，又加之以不得自适的失望与悲哀。这在袁宗道人格心态的五个方面具有极其鲜明的表现。