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.     

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.     

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.     

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.     

方程与粒子穿透几率

在一般情况下,导出了抛物线位垒的穿透几率,并在特殊情况下再现了半经典结果。引入镜像算符讨论了势垒和势阱的互补性,以及Weher方程与Schordinger方程、Hermite方程之问的关系。     

小熊猫肝脏和胆囊的解剖研究

对小熊猫的肝脏和胆囊进行了解剖研究,小熊猫肝脏分为右叶、叶叶和左叶。右叶包括在右外叶、右中叶和右内叶。左叶包括左内叶、左外叶。中叶包括方叶和尾叶,方叶小,尾叶的乳状突粗大。胆囊位于右内叶或右内叶与方叶形成的胆囊窝内,胆囊管有直管和曲管两种类型。肝内结缔组织少,肝小叶分界极不明显。肝细胞呈多边形,具大而圆的细胞核,核仁明显,并将小熊猫与大熊猫的肝脏和胆囊作了比较研究。     

求真务实:先进精神文化意义上的系列新维度

胡锦涛提出的要在全党大力弘扬的求真务实精神,有着精神文化上的多重性,是一个高度综合的富有感召力的先进文化理念,有必要全方位地加以认识、理解和实践。具体应把握以下六个“度”：传统意义上的新厚度、现实意义上的新强度、内涵意义上的新深度、外延意义上的新广度、思想意义上的新高度、实践意义上的新力度,等等。     

"经营城市"与高校管理

“经营城市”是以城市为中心的现代经济所催生出的新的城市管理思路与模式;其基本理念对高校办学和管理不无参考借鉴意义。本文对“经营城市”的理念系统进行了梳理,并结合高校实际,阐发自己对经营城市与管理高校共同点的看法。     

内蒙古二连盆地的构造反转历史

二连盆地中生代经历了复杂的发育历史,是一个多期叠加的盆地系统,它经历了早—中侏罗世的小规模断陷盆地;晚侏罗世的构造反转盆地(伴随着强烈的火山作用);早白垩世的大规模断陷盆地及早白垩世晚期的构造反转等盆地发展阶段;晚白垩世以来本地区处于整体隆升状态。     

白描的潜能——《受戒》语言形象之一

白描,作为一种文学语言表现方式,在《受戒》中得到传承与发展。在传达白描语言的描形、写意、传神语言功能时,汪曾祺将绘画中的骨相比法融入其中,创造出一种简约、空白的语言诗学魅力,而平等视角又将白描对象置于温婉世情当中,体现抒情诗人的人间情怀。《受戒》语言更高的艺术成就在于白描对境界、氛围的营造,其中又深蕴着道家的审美观与语言观。     

关于拓扑空间中一些点集的注记

本文首先给出了拓扑空间中的一个集合为闭集的充要条件,从而进一步得到拓扑空间中的一个集合的闭包和边界集必为闭集并且它的闭包是包含着这个集合的最小的闭集。其次我们知道在一般的度量空间中一个集合的导集必是闭集,但是在一般拓扑空间中此结论不一定成立,所以本文主要给出了在拓扑空间中一个集合的导集为闭集的的充分条件和充分必要条件。     

硬盘分区链表中结点信息的完全恢复算法

通过对分区链表中结点信息的研究 ,及前后结点中相关数据项比较之后 ,参照磁盘基数表中所记录的相应分区长度 ,给出了其中任一结点或整个分区链表丢失之后的修复算法     

白描的潜能——《受戒》语言形象之一

白描，作为一种文学语言表现方式。在《受戒》中得到传承与发展。在传达白描语言的描形、写意、传神语言功能时。汪曾祺将绘画中的骨相比法融入其中，创造出一种简约、空白的语言诗学魅力，而平等视角又将白描对象置于温婉世情当中，体现抒情诗人的人间情怀。《受戒》语言更高的艺术成就在于白描对境界、氛围的营造，其中又深蕴着道家的审美观与语言观。     

日光温室微喷系统的键图模型

微喷系统是日光温室中环境调节与控制、作物的生长与发育、优质和高产的根本保证。因此，微喷系统的性能对于日光温室的生产与效益有直接的影响。文中利用功率键图的理论与方法，分析、建立了温室微喷系统的键图模型，为研究日光温室微喷系统的动态性能、评价和改进微喷系统的设计奠定了理论基础。