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.     

异构网络安全设备统一管理平台研究与构建

随着网络应用的不断发展,网络中安全设备的类型和数量不断增多,出现了异构安全设备难以协同、海量告警信息难以处理以及对安全事件缺乏有效的响应处理流程等问题。针对这些问题,提出设计一种针对多种异构网络安全设备的统一管理平台。本文简单介绍了平台的主要功能,提出了一种异构安全设备通信处理机制,使平台能够最大程度的支持异构安全设备。     

浅谈我国三代领导集体的国家安全观

国家安全直接体现着国家利益—我国党的三代领导集体为维护国家利益分别提出了以军事安全为核心的安全观，以综合安全为特征的安全观和以普遍安全为核心的安全观。三代领导集体的国家安全观虽然各有侧重，但都是实事求是，从特定的时代、特定的国情出发提出的，都起到了应有的作用。而义它们在基本思想上是一致的，后是对前的继承和发展。     

试论计算机网络安全

随着现代信息技术的发展和应用,网络安全问题日益突出。文章对网络安全的含义、网络面临的安全威胁、网络安全目标做了初步的探讨,同时介绍了当前网络采用的各种安全防范技术、网络安全策略、网络安全的发展趋势等,这对我们认识网络和网络安全具有很强的参考价值。     

网络安全研究

阐述了在现代社会生活中网络安全的重要性,分析了导致网络安全问题产生的原因和目前对网络进行攻击的手段,介绍了一些防范攻击、保护安全的关键技术,提出了构建综合网络安全体系的方案。     

“人的安全”是国家安全之本

20世纪90年代以来,"人的安全"问题成为跨国性"非传统安全研究"的关注焦点."人的安全"概念试图整合国际体系层面的"人类安全"、国家体系层面的"国民安全"、次国家层面的"团体安全"和个体层面的"公民安全",将"人的安全"和普通人日常生活的安全视为国家安全的根本目的."人的安全"研究鼓励各国重视人权教育、建立良政和民主体制,并提醒关注那些严重影响我们每个人安全的个人生活方式、群体关系模式和国家间关系模式.     

从重视粮食安全提升为树立科学的食物安全观

文中分析了粮食和食物两个概念的区别：指出了以我国传统的粮食安全观指导农业生产的危害：提出应以食物安全观为指导,统筹规划碳水化合物、油脂和蛋白质等主要营养素的生产和供给,在重视可耕地的粮食生产的同时。也要兼顾其它农作物以及林地、草地、淡水和海洋食物的综合开发：既要考虑满足当前的食物需求,也要考虑食物生产的可持续发展。     

论我国所面临的非传统安全威胁及主要应对方略

非传统安全和传统安全同属于综合安全观范畴，而非传统安全威胁的日益凸显，则在一定程度上催生了综合安全观的产生和发展。对分别来自于政治、经济、环境和信息等四大领域的非传统安全威胁进行分析研究，可以较全面地了解我国所面临的各种非传统安全威胁与其他国家的共性和个性，从而提出相应措施。     

试论我国社会保障法的制定与完善

社会保障法是保障生存权利的社会互助法，具有以社会利益为本位，以社会公平为价值追求，以强制为手段的特征。我国社会保障法应当包括基本法、救济法、保险法、福利法和优抚安置法。建立我国的社会保障体系应当采取循序渐进、逐渐统一的办法。     

非传统安全视角下中国新安全观的转型

指出非传统安全问题日趋严峻，分析了非传统安全被纳入到中国新安全内涵之中，并推动中国新安全观朝着“综合安全”、“以人为本”、“合作安全”之新安全观方向转型。     

基于信息安全控制原理的安全网格技术

结合网格系统安全性问题的研究,分析了传统GSI的缺点以及网格系统及其安全性的特点.针对提高其可扩展性和动态特性的具体要求,提出了信息安全控制的思想,阐述了信息安全控制原理的理论基础和具体内容,研究实现了基于信息安全控制原理的安全网格模型,通过建立安全控制策略库、安全网格认证模块和安全网格控制模块,构建了具有反馈功能的安全网格模型,提高了网格系统的可扩展性和动态性能.该文提出的安全网格技术为进一步提高网格的安全性提供了新的思路.