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.     

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.     

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.     

含钛高炉炉渣微波合成碳化钛及其介电性能测定

The preparation of functional material titanium carbide by the carbothermal reduction of Ti-bearing blast furnace slag with microwave heating is an effective method for valuable metals recovery; it can alleviate the environmental pressure caused by slag stocking. The dynamic dielectric parameters of Ti-bearing blast furnace slag/pulverized coal mixture under high-temperature heating are measured by the cylindrical resonant cavity perturbation method. Combining the transient dipole and large π bond delocalization polarization phenomena, the interaction mechanism of the microwave macroscopic non-thermal effect on the titanium carbide synthesis reaction was revealed. The material thickness range during microwave heating was optimized by the joint analysis of penetration depth and reflection loss, which is of great significance to the design of the microwave reactor for the carbothermal reduction of Ti-bearing blast furnace slag.     

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.     

人类未来的进化问题

人类过去几百万年的进化史,已经充分说明人类作为生物的一分子,同样遵循达尔文的进化理论:物竞天择、适者生存。这种适应环境的自然选择进化在未来的人类进化中还会起作用吗?达尔文的进化理论是否适用于未来的人类?本文将通过详细的分析试图回答这个问题。现在的人类已经知晓设计人类自身生命的蓝图:DNA,并必然会在未来的几百万年中充分利用基因技术服务和改造人类自身,所以适应环境的自然选择进化还会在多大程度上影响人类的进化是一个值得研究的问题。本文中分析了自然进化和人为进化的区别,以及它们各自在人类未来进化中的作用,同时给出了一种未来文明分类标准,提出了智慧文明的局域同步发展说,用这样的学说可以解释为什么人类至今还没有发现外星人。     

酶定向进化技术研究进展

酶定向进化是模拟自然进化过程、用于改造酶性质的一种新策略．在以易错PCR为代表的无性进化技术基础之上,有性进化技术的发展使酶定向进化更接近于自然进化过程．与此同时为解决巨大容量的突变文库与有限的筛选技术之间的矛盾,许多新的高通量筛选方法不断涌现,大大加快了酶定向进化技术的发展．文章从构建高质量的突变基因文库和选择有效的高通量筛选方法两方面,详细总结了近几年出现的新技术并对其应用情况进行介绍．     

金属材料在重复冲击下的损伤演化

为了探究金属材料在重复冲击下的损伤演化规律,基于Lemaitre损伤演化模型,提出了两种损伤演化方程建立方法:直接法和修正法.基于这两种方法建立了7075铝合金的损伤演化方程,并对两种损伤演化方程进行了对比研究,结果表明:直接法和修正法得到的损伤演化方程形式不同,但其损伤演化曲线十分相似,对试样失效前的可冲击次数预测十...     

基于自适应HereBoy算法的电路进化设计实验研究

针对电路进化设计演化后期种群收敛速度放慢等问题,采用自适应Here Boy算法,融入遗传算法的群体概念,研究自适应因子在进化算法中对演化收敛速度的影响。运用类神经网络的电路模型和矩阵编码方法对组合电路进行编码,建立了电路编码到电路功能的映射关系,采用外部进化方式进行电路适应度值评估,引入自适应遗传算子提高算法收敛速度和种群多样性。二位二进制乘法器电路的进化结果表明,该方法较传统Here Boy算法在电路进化设计进程中电路平均演化代数及演化时间明显减小,在进化后期,随着种群演化代数增加适应度值平均涨幅提高。     

决策演化集的伯努利移位

决策演化集是一种新的用来解决决策规则在时间序列上变化问题的方法。决策演化矩阵是其中一个重要概念。通过决策演化矩阵可以直观了解到各个条件属性在单个时间点以及连续时间序列上的表现。但目前的体系中虽然对决策演化矩阵进行了定义,但还缺乏数值量化,文章引入伯努利移位来对决策演化矩阵进行数值量化,并通过实例演示这些量化后的数值在预测中所起的作用。     

网络化软件自适应动态演化技术的趋势分析

综述了网络化软件自适应动态演化技术,以软件演化基本概念为基础,深刻分析了网络化软件自适应动态演化的动因,重点评述了网络软件自适应动态演化技术在需求捕捉、情境建模、感知操作、决策技术、演化操作五个方面的发展现状,由此指出网络化软件自适应动态演化面临的挑战和发展趋势.     

生物进化树中的模糊问题浅论

生物进化树是生物进化序列的特殊表现形式,它是生物进化论研究取得的重要成就,但生物进化树仍存在一些模糊问题．本文根据现代生物学、生物进化论、古生物学成就,就存在的模糊问题、产生原因及研究意义进行了浅简的论述.     

物质进化论

世界是物质的。由少数到多数,由简单到复杂,由低级到高级,物质不断地向前进化。物质进化分为阶段进化和层次进化。阶段进化经历了非生物阶段、生物阶段和人类阶段。层次进化经历了个体层次、群体层次和积体层次。当今世界,不仅非生物群体和生物群体积合成物物积体,而且非生物群体、生物群体和人类群体积合成物人积体,成为复合积体。进化的动因是组分作用和组分适应。进化的动力是组分矛盾。人类阶段物质进化的方向是共产主义物人积体。     

湘南庙会的变迁及其动因研究——以永兴汉三侯祠为例

对湖南永兴汉三侯祠庙会变迁的动因来说，总的社会环境是庙会变迁的主要原因，地方政府是庙会变迁重要的推动力，地方非正式权力是庙会变迁的主要推动力。     

一种基于演化代价约束的本体演化方法

针对本体演化方法提出粒度最小的演化基本操作,即附加演化元操作并引入了演化代价的概念;根据实体对本体影响内容的不同将其分类进行量化分析,实现了演化代价的计算方法;为减少本体演化中的演化代价,适应复杂的本体演化环境,给出一组演化操作策略集,以简化演化过程.实验结果表明,该COST启发式算法可以降低演化代价,有效减少了搜索空间并加速了演化过程.