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.     

Carbon sequestration within millet phytoliths from dry-farming of crops in China

Phytoliths are noncrystalline minerals that form inside cells and cell walls of different parts of plants. Organic carbon in living cells can be occluded in phytoliths during plant growth. It has been documented that the occluded carbon within phytoliths is an important long-term terrestrial carbon reservoir that has a major role in the global carbon cycle. Common millet and foxtail millet have become typical dry-farming crops in China since the Neolithic Age. The study of carbon conservation within phytoliths in these crops could provide insights into anthropogenic influences on the carbon cycle. In this study, we analyzed the carbon content in phytoliths of common millet and foxtail millet. The results indicated that (1) common millet and foxtail millet contained 0.136% ± 0.070% and 0.129% ± 0.085% phytolith-occluded carbon (PhytOC) on a dry mass basis, respectively; (2) based on the mean annual production of common millet and foxtail millet in the last 10 years, the phytolith occluded carbon accumulation rate of common millet and foxtail millet was approximately 0.023 ± 0.015 and 0.020 ± 0.010 t CO 2 ha 1 a 1 , respectively; (3) assuming a similar phytolith occluded carbon accumulation rate as for common millet (the highest accumulation rate was 0.038 t CO 2 ha 1 a 1 ), this could result in the sequestration of 2.37 × 10 6 t CO 2 per year for the 62.4 × 10 6 ha dry-farming crops in China. Although there was a decline in the annual production rate and planting area of foxtail millet during 1949 to 2008, the total phytolith carbon sequestration rate was 7×10 6 t CO 2 within the 60-year period. However, phytolith occluded carbon has not yet been fully considered as a global carbon sink. Also, this carbon fraction is probably one of the best candidates for the missing carbon sink.     

Component and simulation of the 4,000-year-old noodles excavated from the archaeological site of Lajia in Qinghai,China

Noodles are a global food, but the periods when and places where they were made and originated, as well as their ingredients and the cooking methods used to manu- facture them, have remained contentious. In the 2005 edi- tion of the journal Nature, we wrote a summary of the millet noodle specimens found in the Late Neolithic Qijia cultural stratum of the Lajia archaeological site in Qinghai Province, China. However, how the ancient people made millet noodles remains controversial. This paper provides a systematic analysis of the remains of noodles found within an earthenware bowl at the Lajia ＂noodle house＂ in terms of their plant composition including phytoliths, starch and biomarkers. It provides evidence of how people used millet 4,000 years ago and, most specifically, of the principal methods used for producing millet-based noodles. Further, we show how we used traditional hele tools to make hele millet noodles, with especial reference to the gelatinized hydrogel-forming method, to simulate morphology con- sistent with the composition and form of the unearthed millet noodles. The results of this study provide new evi- dence and new insights into the cultural characteristics of the prehistoric human diet.     

Plant crop remains from the outer burial pit of the Han Yangling Mausoleum and their significance to Early Western Han agriculture

A large amount of carbonized plant remains were discovered in one of the outer burial pits of the Han Yangling Mausoleum, which was built more than 2000 years ago for the Jing Emperor, Liu, Qi (188―141 cal a BC), the fourth emperor of the Western Han Dynasty. The remains are identified by phytolith analysis and macrofossil morphological features. Seeds from foxtail millet (Setaria italica), broomcorn millet (Panicum miliaceum), rice (Oryza sativa) and chenopod (possible Chenopodium giganteum) are identified...     

Sea surface temperature record from the north of the East China Sea since late Holocene

Using the alkenone paleotemperature index U37^k, a high-resolution sea surface temperature （SST） record since 3600 a BP was reconstructed from the mud area in the north of the East China Sea. Combining with the grain size distribution curve of sensitive grain size group, which may reflect the East Asia Winter Monsoon activity, the palaeoenvironmental evolution cycle throughout the late Holocene in the area was obtained. The marine environment evolution during the last 3600 years displays a five-stage trend. （1） Temperature descending period from 0.85 cal. ka BP to present. The maximum temperature decrease amplitude is 2℃. The winter monsoon intensified and ＇Little Ice Age＇ were recorded in this period. （2） Warming period from 1.90 to 0.85 cal. ka BP. The mean temperature increase amplitude is 0.8℃. The Sui-Tang warming period was recorded at about 0.85--1.35 cal. ka BP and a prominent cooling event was recorded at 1.4 cal. ka BP in this period. （3） Temperature descending period from 2.55 to 1.90 cal. ka BP. Temperature cooling amplitude is 0.9℃. This period is coincident with an integrated temperature circle recorded in the Antarctic ice core, with the temperature changes from a slow cooling stage to a rapid warming stage. （4） Temperature comparatively stable with a little ascending period from 3.2 to 2.55 cal. ka BP. Temperature warming amplitude is 0.3℃. This period is coincident with the temperature fluctuant ascending period recorded in Antarctic ice core. （5） Temperature comparatively stable with little descending period from 3.6 to 3.2 cal. ka BP. This period corresponds with the temperature fluctuant cooling period recorded in Antarctic ice core. Basically, those five periods were coincident with the Antarctic ice core record. During the global cooling stage, the SST change in the continental shelf sea can be adjusted simultaneously.     

中国富硒谷子产业现状及发展方向

为明确中国富硒地区、谷子主产区以及富硒谷子产品的现状,采用数据统计、文献资料、网络资源、专家访谈、实地调研等方式取得数据资料,对中国富硒地区、谷子主产区、富硒谷子产品等资料进行整理、分析,筛选出适合不同区域生产的富硒谷子品种,指出了富硒谷子产业的发展方向,为提高中国富硒谷子产业化水平提供借鉴。     

The foxtail millet Si69 gene is a Wali7 (wheat aluminum-induced protein 7) homologue and may function in aluminum tolerance

We isolated a clone, named Si69, from a foxtail millet immature seed cDNA library. The protein encoded by Si69 contains a conserved Wali7 (wheat aluminum induced protein 7) domain and shares high-level homology with aluminum-induced proteins from other species including rice and Arabidopsis. The Si69 gene presents as a single locus in foxtail millet genome and is globally expressed in all tissues examined. Its expression is up-regulated by aluminum. The sequence feature and expression pattern suggest that the Si69 gene is involved in aluminum tolerance or detoxification. To confirm its biological functions, Si69 controlled by the CaMV35S promoter was introduced into Arabidopsis. Transgenic plants did not show any visible morphological changes compared to wild-type plants under normal growth conditions. However, when treated with 20 or 50 μmol/L Aluminum (Al), the root apices of wild-type plants were heavily stained by hematoxylin, whereas those of Si69 transgenic plants were not stained when treated with 20 μmol/L Al and slightly stained when treated with 50 μmol/L Al. Scanning electron microscopy (SEM) results further demonstrated that the damage of the root apices was severer in wild-type plants than in transgenic plants. Inhibition of root growth and accumulation of malondialdehyde (MDA), an indicator of lipid peroxidation, were lower in transgenic plants than in wild-type plants. The results show that overexpression of Si69 may increase Al tolerance in transgenic plants, indicating that a series of Wali7-containing genes may play similar roles in Al tolerance/detoxification.     

Investigation of the ultrastructural characteristics of foxtail and broomcorn millet during carbonization and its application in archaeobotany

Fossilized caryopses (or grains) of foxtail millet (Setaria italica) and broomcorn millet (Panicum miliaceum) are important archaeobotanical materials for the study of early human agricultural activities.The morphology and ultrastructural characteristics of carbonized modern millets caryopses treated in a drying oven and burning in a field were investigated at different temperatures to study how fossilized millets are formed.The caryopses shrank gradually at temperatures below 200°C,and starch granules in the endosperm retained their crystalline structure.At 250°C the foxtail millet caryopses expanded,whereas the broomcorn millet caryopses were greatly deformed.At this temperature,the structure of the starch granules of both millets became amorphous.At 300°C the caryopses partially turned to ash and became porous,and the ultrastructure of the starch granules was transformed into alveolate cavities.Fossil caryopses from the prehistoric storage cellar at the Beiniu Site retained their crystalline structure and were formed by the dehydrating effect of carbonization,indicating that water molecules were not involved in the starch crystallization.The results of a field burning experiment demonstrated that the ultrastructure of carbonized caryopses placed on the ground under the fire was amorphous.The amorphous ultrastructure of the carbonized caryopses recovered from the archaeological layers is consistent with the expected structure of caryopses that have been carbonized at 250°C.Therefore,we suggest that the recovered caryopses were formed at about 250°C by baking rather than by burning in an open fire.     

Pollen record and environmental evolution of Caotanhu wetland in Xinjiang since 4550 cal. a BP

This paper presents a multi-proxy reconstruction of the climate change in Caotanhu wetland using pollen, phytolith and charcoal records, and the data of loss of ignition （LOI）, grain size analysis, and susceptibility. Results reveal that between 4550 and 2500 cal. a BP, a dry climatic condition was not favorable for the accumulation of peat. Since 2500 cal. a BP, the climate became humid and the wetland developed with abundant freshwater aquatic plants, which contributed to peat accumulation. Never-theless, alternate periods of rain and dry climate occurred during that period. Between 2500 and 1810 cal. a BP （550 BC-140 AD）, the climate was more humid than at present. A lot of emerged plants, such as Phragmites, Typha and Sparganium, and freshwater green algae grew in the wetland which was sur-rounded by desert-steppe vegetation composed mainly of Chenopodiaceae, Artemisia, Compositae and Thalictrum. However, from 1810 to 1160 cal. a BP （140--790 AD）, the water level started to decrease and hydrophyte species reduced greatly, but some Phragmites still grew in the wetland and around it was desert vegetation with high proportion of Chenopodiaceae and Artemisia. Then from 1160 to 650 a BP （790--1300 AD）, it entered a period of desert-steppe with abundant mesic and xerophytic plants. And a lot of aquatic plants prevailed in the wetland. Here, what is noticeable is that percentages of arboreal pollen, consisting mainly of Betula and Picea, increased greatly and reached a maximal value of 27.2%, in which, Betula percentages rose to 23.2%. Hence, it is reasonable to conclude that Betula grew in the highland of the wetland, or Picea timberline shifted downward resulting in the increase of percentages of Betula and Picea pollen, which were transported into the wetland by flood or wind. But since 650 cal. a BP, desert vegetation prevailed around the wetland again with dominant Chenopodiaceae and Artemisia, and the climate was similar to modern one. Despite some aquatic plants still growing in the wetland at     

小米蛋白的营养消化性研究

采用体外模拟消化法分别对小米乳、小米醇提蛋白、小米分离蛋白进行营养消化性分析.研究发现,与对照大豆乳相比,小米乳中的蛋白质表现出较低的消化率,仅为35.2％.其中,小米蛋白主要成分之一醇溶蛋白是导致小蛋白消化率较低的主要原因.醇溶蛋白本身形成的二硫键以及其强烈的疏水性是导致其不被消化的关键因素.     

Analysis of the ecological environment around 10000 a BP in Zhaitang area,Beijing: A case study of the Donghulin Site

The transition from Paleolithic to Neolithic around 10000 a BP was a significant event in human history. We have analyzed the paleoenvironment in the Zhaitang area (Beijing) based on samples from an early Neolithic site at Donghulin. This site is considered to demonstrate the Paleolithic-Neolithic transition in this area. The site yielded burials with several human skeletons, known as "Donghulin man". We conducted a geomorphological and quaternary geological investigation in the Donghulin area, and also analyzed sediments and pollen, enabling us to discuss the living environment of the local people. Donghulin man lived mainly from 11100-9600 cal a BP; a period of warming following the Younger Dryas. The climate was good, the land was covered by dry temperate grassland, and later, wet temperate meadow steppe. "Donghulin man" usually inhabited the floodplain; this was flat, warm, and wet, with abundant plants and animals for a favorable living environment. Our research helps to rebuild the living environment of humans in the Beijing area around 10000 a BP, and to understand more about the environmental setting in north China during the Paleolithic-Neolithic transition.