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.     

浙江温州、镇海和福建九龙江沉积微型硅藻的初步研究

利用透射电镜研究了温州早、中全新世剖面,九龙江地区晚全新世中期剖面和镇海晚全新世剖面的微型硅藻(细胞大小为2～20μm)的组成和丰度.共计硅藻14属20种(包括变种).Cyclotellacaspia是九龙江地区晚全新世中期剖面中的优势种;温州中全新世剖面的优势种为Cyclotellastriata;温州早全新世剖面和镇海晚全新世剖面中Thalassionemanitzschioides是优势种.微型硅藻在几个剖面中所占的比例变化较大,以在九龙江地区晚全新世中期剖面所占的比例最高,可达77.4%,表明微型硅藻在沉积硅藻中占有重要的地位.     

临夏回族青少年头发和指甲微量元素含量对比分析

对500名(男246,女254)13～17岁临夏回族青少年头发和指甲中的Fe、Cu、Ni、Zn、Mn、Pb、Cd、Mo、Se和Ca元素的含量进行了对比分析。结果表明这十种元素在人体的头发和指甲中均存在,但男女之间有差异,其共同特点是头发中的Cu、Zn高于指甲,Cd、Mo和Se元素的含量男女均极少,且无差异(p>0.05),男女指甲中的Pb、Fe含量均高于头发(p<0.05);男性指甲中的Mn高于头发(p<0.05),而在女性无显著差异;Ca作为一种常量元素,男女指甲中的含量均极显著地高于头发(p<0.01)。证实测定人体微量元素时,只测定头发中的含量不能完全代表元素的分布特征和变化情况,指甲和头发对于研究人体微量元素具有同等重要的意义。     

茶园土壤中铅形态分布与茶叶中铅质量分数关系的研究

基于茶园土壤中0～100 cm剖面不同层位各种形态铅及茶叶样品中总铅质量分数(w)的测定分析结果,定量分析了各种形态铅在不同土壤层位中的叫及其分布特点,同时利用灰色关联度分析方法,估算了土壤剖面不同层位中5个形态铅即可交换态(EXE)、碳酸盐结合态(CA)、铁锰氧化物结合态(OX)、有机结合态(OM)和残渣态(REX)的w与茶叶中总铅硼的相关性.研究结果显示:茶园土壤中不同形态铅w在所测剖面范围内的平均值由大到小排序为:叫(REX):>w(OX)>硼(0M)>w(CA)>w(EXE);同一剖面内铅的分布特点为:w(EXE),w(OM),w(REX)为表层高于底层,w(CA)和w(OX)则是底层高于表层;各形态铅所占总铅的比例,随其在土壤剖面各层中w值的变化而变化,其中 EXE铅在各土壤层中所占比例最小,REX铅所占比例最大(除底层外);灰色关联度分析结果显示,茶叶中的铅叫与不同形态铅在土壤各层中的w均呈正相关,但关联度最大的是EXE铅,其次为OM铅,且以表层土壤中的铅对茶叶中铅的w影响最大.     

2006年中国重大科学进展

本着“分门别类、宁缺毋滥、叙述事实、以时为序”的原则,按“基础科学”、“生命科学”、“资源环境”和“高新技术基础研究”4个类别,遴选出2006年中国重大科学进展共30项,其中“基础科学”领域13项、“生命科学”领域7项、“资源环境”领域4项和“高新技术基础研究”领域6项。     

茶园土壤中铅形态分布与茶叶中铅质量分数关系的研究

基于茶园土壤中0~100 cm剖面不同层位各种形态铅及茶叶样品中总铅质量分数(w)的测定分析结果,定量分析了各种形态铅在不同土壤层位中的w及其分布特点,同时利用灰色关联度分析方法,估算了土壤剖面不同层位中5个形态铅即可交换态(EXE)、碳酸盐结合态(CA)、铁锰氧化物结合态(OX)、有机结合态(OM)和残渣态(REX)的w与茶叶中总铅w的相关性.研究结果显示:茶园土壤中不同形态铅w在所测剖面范围内的平均值由大到小排序为:w(REX)>w(OX)>w(OM)>w(CA)>w(EXE);同一剖面内铅的分布特点为:w(EXE),w(OM),w(REX)为表层高于底层,w(CA)和w(OX)则是底层高于表层;各形态铅所占总铅的比例,随其在土壤剖面各层中w值的变化而变化,其中EXE铅在各土壤层中所占比例最小,REX铅所占比例最大(除底层外);灰色关联度分析结果显示,茶叶中的铅w与不同形态铅在土壤各层中的w均呈正相关,但关联度最大的是EXE铅,其次为OM铅,且以表层土壤中的铅对茶叶中铅的w影响最大.     

英语同义词特点之初探

就英语同义词在语义上的不同、感情色彩上的不同、语体色彩上的不同、词汇搭配上的不同、语法功能上的不同、不同国家选词上的不同等六个方面进行论述。     

贵州省制造业信息化人才培训现状与存在的问题

介绍了贵州省制造业信息化人才培训所采用的技术路线,阐述了贵州省制造业信息化人才培训解决的关键技术问题,时贵州省制造业信息化人才培训中取得的阶段性成果及存在的问题进行了探讨.     

南方涛动对广西干旱的影响

通过对南方涛动指数与广西春秋干旱的时空变化规律及与影响广西春秋降雨的天气系统的关系的分析。找出了7月及头年8月南方涛动指数分别与秋季和次年春季降雨的关系较为密切。并且,这两个月的南方涛动指数对影响春、秋降雨的天气系统有明显的制约作用。用这两个月的SOI值制作的春秋干旱的GM(1,2)模型,其效果较令人满意。     

Cellular distribution of arsenic and other elements in hyperaccumulator<Emphasis Type="Italic">Pteris nervosa</Emphasis> and their relations to arsenic accumulation

Synchrotron radiation X-ray fluorescence spectroscopy (SRXRF) was used to study the cellular distributions of arsenic and other elements in root, petiole, pinna of a newly discovered arsenic hyperaccumulator, Pteris nervosa. It was shown that there was a trend in P nervosa to transport arsenic from cortex tissue to vascular tissue in root, and keep arsenic in vascular during transportation in petiole, and transport arsenic from vascular tissue to adaxial cortex tissues in midrib of pinnae. More arsenic was accumulated in mesophyll than in epidermis in pinnae. The distributions of some elements, such as K, Ca, Mn, Fe, Cu, Zn, in petiole, midrib and pinna were similar to that of arsenic, indicating that those cations might cooperate with arsenic in those transportation processes; whereas the distributions of CI and Br in pinna were the reverse of that of arsenic, indicating that those anions might compete with arsenic in pinna of P. nervosa.     

贫困地区乡镇企业发展中需解决的几个问题

贫困地区的乡镇企业在发展中如何才能取得成功,本文从4个方面进行了论述,即加强企业在观念上的自我改造,在制度上的自我创新,在经营上的自我提高,在管理上的自我完善。