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.     

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.     

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.     

太极柔力球结合决明子茶饮对肥胖女大学生的干预影响

目的：探讨太极柔力球结合决明子茶饮对单纯性肥胖女大学生身体形态与血脂代谢的双重干预影响效果,为女大学预防超重尤其是肥胖的发生发展提供参考依据。方法：随机选取某高校肥胖女大学生80名为研究对象。在知情、自愿的原则下,随机分成人数相等的实验组和对照组（实验组有2人,对照组有1人因其他原因中途退出）,实验组每人每天饮用一份决明子茶并练习36式太极柔力球40min,对照组仅每天与实验组同时同地进行太极柔力球练习,共计60d。结果：太极柔力球结合决明子茶饮对肥胖女大学生血压有显著的改善作用（P〈0．01）,减慢安静心率（P〈0．01）,提高心肺功能（P〈0．01）,显著降低体重、BMI值（P〈0．01）,减少脂肪在腰腹部的堆积（P〈0．01）,使腰臀比趋于合理（P〈0．01）,对血脂代谢的TG、CHOL、HDL、LDL、ApoAI、ApoB等指标有显著的良性改善作用（P〈0．01）,是肥胖女大学生保持苗条身材、抑制和预防肥胖的一个较好的选择。     

超重和肥胖与脂肪肝的相关性分析

目的：调查拉萨市墨竹工卡县不同人群脂肪肝的患病率,分析脂肪肝与体质指数、性别、职业之间的关系。方法：对随机抽样的247名干部和365名农牧民测量的身高、体重、腹部B超检查结果进行统计分析。结果：墨竹工卡县脂肪肝的患病率为15.4%;脂肪肝组的超重和肥胖检出率为74.5%,明显高于非脂肪肝组的27.8%;男、女性脂肪肝患病率无差异;不同各职业间患病率有显著差异。结论：脂肪肝的发病与超重和肥胖密切相关,控制体重是降低人群脂肪肝患病率的重要措施。     

体力活动视角下建成环境对成年人健康的影响研究

肥胖率上升给公共健康带来严峻威胁,有效的体力活动能够降低肥胖、高血压、心脑血管疾病等慢性病的发病率,是增进人群健康的重要途径;提高居民体力活动水平已经成为世界众多国家面临的严峻挑战。建成环境是城市规划建设在空间上的反映,是影响居民体力活动和健康的重要载体,已有的研究表明,建成环境会对体力活动和肥胖情况产生重要影响;以重庆市主城区为例,选择成年上班群体为研究对象,假设建成环境变量会影响其交通体力活动和休闲体力活动,进而影响其肥胖程度;研究结果表明:通勤距离、公共交通站点距居住地(工作地)的距离、最近体力活动场所距居住地(工作地)的距离、一周内去休闲体力活动场所的次数等建成环境变量与成年上班群体身体质量指数(BMI)之间存在显著联系;提出了强化成年上班群体体力活动,减少肥胖发生的建成环境优化建议。     

黑果枸杞花色苷的肥胖干预作用研究进展

肥胖是目前受到世界广泛关注的慢性病之一,是心脑血管疾病及癌症等多种疾病的危险因素,成为目前威胁人类社会最主要的健康问题。现有减肥药物或方法大都存在毒副作用大、易反弹等缺点。因此,寻求安全、有效的干预肥胖的药物或方法具有极其重要的意义。花色苷等天然植物提取物具有有效干预肥胖的作用,且副作用小,相关研究与开发逐渐成为一个热点。黑果枸杞是近年来新发掘的食用植物资源之一,具有降血脂、抗氧化、抗突变、抗癌、抗炎、提高机体免疫力等多种生物学活性。黑果枸杞主要发挥机体营养健康作用的成分是有别于常见果蔬中的花色苷类物质,其花色苷结构同时具有矮牵牛素母核、芳香酸酰化等特征,且总花色苷含量远超于其他有色果实。通过总结国内外相关文献,综述黑果枸杞花色苷的肥胖干预作用研究进展,为黑果枸杞开发利用提供理论参考。     

煤层巷道小断层预测的空间解析几何方法

本文提出一种预测煤层巷道中小断层的新方法。此法是根据空间解析几何的原理,通过建立煤层的参照平面,求出测点对参照面的偏差值,并作出d—s折线图,进而获得巷道前方断层的信息。     

猪脂肪细胞生脂及其调控研究进展

肥胖已成为严重威胁人类健康的流行病,猪作为研究肥胖及相关疾病的动物模型已引起人们的关注.通过介绍碳水化合物、蛋白质、激素等因素对猪脂肪生成的调控,期待为预防和治疗威胁人类健康的疾病提供有益的帮助.     

对传递闭包两个结论的改进

本文讨论了集合上二元关系的传递闭包，提出了传递闭包的链形表示以及改进了求传递闭包关系矩阵的沃夏尔（Ｗａｒｓｈａｌｌ）算法，使之更为实用。     

青少年肥胖评定方法的研究进展——质疑与思考

青少年肥胖问题已日益严重,其体质指数法、皮褶厚度法、水下称重法等评价方法的测试原理和参照模型是在对成人人体测量评价数据研究的基础上建立起来的,对不同年龄、不同地区和不同种族青少年的解剖生理特点缺乏特异性.通过概况青少年肥胖评定方法的研究进展,结合不同青少年人群的行为与解剖生理特点,探讨符合不同青少年特点的评定原则和研究...     

用有限组合元法分析外包T型叶根小脚装配间隙的影响

本文通过有限组合元法分析了外包小脚装配间隙对叶根轮缘强度的影响。得出了在工艺许可条件下,小脚装配间隙宜尽量减小的结论。