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To realize an industrial production of a cerium‐treated electroslag remelted H13 steel, electroslag remelting (ESR) of H13 steel using a CaF2–CeO2–CaO–Al2O3 system slag combined with a Si–Ca reductant addition is studied. The influence of the Al2O3 content in the slag on the cerium treatment effect of cerium‐oxide‐containing slag is investigated to determine the appropriate slag. A 52.2 wt% CaF2–26.7 wt% CeO2–17.8 wt% CaO–3.3 wt% Al2O3 slag (RE‐Slag) is employed for the industrial ESR production of H13 steel. An H13 steel remelted by a 70 wt% CaF2–30 wt% Al2O3 slag (CA‐Slag) is used for comparison. Al2O3 can suppress the reduction of cerium oxide by changing the activities of slag components. ESR with RE‐Slag achieves a cerium treatment of H13 steel. However, an uneven distribution of Ce is obtained due to the limitation of the reductant addition method. The H13 steel remelted with RE‐Slag (RE‐Slag‐H13) has higher cleanliness, finer dendritic structures, and finer primary carbides than those of the steel remelted with CA‐Slag (CA‐Slag‐H13). Compared to the forged CA‐Slag‐H13 steel, the banded segregation of the RE‐Slag‐H13 steel is suppressed, and the impact toughness is increased by 30%. [ABSTRACT FROM AUTHOR]

Gas‐mediated sonodynamic therapy (SDT) has the potential to become an effective strategy to improve the therapeutic outcome and survival rate of cancer patients. Herein, titanium sulfide nanosheets (TiSX NSs) are prepared as cascade bioreactors for sequential gas–sonodynamic cancer therapy. TiSX NSs themselves as hydrogen sulfide (H2S) donors can burst release H2S gas. Following H2S generation, TiSX NSs are gradually degraded to become S‐defective and partly oxidized into TiOX on their surface, which endows TiSX NSs with high sonodynamic properties under ultrasound (US) irradiation. In vitro and in vivo experiments show the excellent therapeutic effects of TiSX NSs. In detail, large amounts of H2S gas and reactive oxygen species (ROS) can simultaneously inhibit mitochondrial respiration and ATP synthesis, leading to cancer cell apoptosis. Of note, H2S gas also plays important roles in modulating and activating the immune system to effectively inhibit pulmonary metastasis. Finally, the metabolizable TiSX NSs are excreted out of the body without inducing any significant long‐term toxicity. Collectively, this work establishes a cascade bioreactor of TiSX NSs with satisfactory H2S release ability and excellent ROS generation properties under US irradiation for programmed gas–sonodynamic cancer therapy. [ABSTRACT FROM AUTHOR]

The vaporization and crystallization of CaF2–CaO–Al2O3 slags with different MgO contents for electroslag remelting were investigated by various analytical methods. The results show that the main volatiles from investigated slag with 8.8 mass% MgO content at 1723 K are CaF2 and AlF3 and contain trace MgF2. The mass loss of CaF2–CaO–Al2O3–(MgO) slag decreases with the increase of MgO content. The addition of MgO within 8.8 mass% has little effect on the viscosity of investigated slag, implying that the viscosity change is not the reason to inhibit the fluoride vaporization. At 1723 K, the vapor pressures of CaF2 and AlF3 decrease with the increase of MgO content; thus, fluoride vaporization becomes weak. The fluoride vaporization of slag with MgO addition under vacuum at 1823 K is also inhibited. The MgO addition can decrease the crystallization temperature of 11CaO·7Al2O3·CaF2, but excessive MgO addition can lead to the precipitation of MgO. [ABSTRACT FROM AUTHOR]

In order to understand the mechanism of lining failure caused by creep, it is significant to evaluate the three creep stages of lining materials. In this paper, the three stages creep curves of 3 MPa, 3.25 MPa and 3.5 MPa for high alumina bricks at 1350 °C were obtained by high temperature creep testing equipment. Then the K-R model, the Sinh model and the Liu-Murakami model combined with the Garofalo formula are used to fit the measured creep curves. The results show that all the three models are suitable for the description of the creep behavior and the creep life prediction of high alumina bricks, and the Sinh-Garofalo model has the best fitting effect. Therefore, the Sinh-Garofalo model is selected for finite element modeling. The reliability of the model is verified by comparing the simulated and analytical values. Finally, by comparing the model with/without considering the creep damage, it is found that the creep damage model can be used to characterize the creep damage evolution process and predict the life of structures, which can be further used in the failure study of furnace lining. [ABSTRACT FROM AUTHOR]

The corrosion of refractory is generally related to the wetting between slag and refractory. Investigating the wetting and corrosion characteristics of refractory by molten slag has a positive significance to elucidating the corrosion mechanism and understanding the slag resistance. In this work, the apparent contact angles of the CaO–Al 2 O 3 –SiO 2 –(MgO) molten slags on microporous magnesia aggregate (MM) and fused magnesia (FM) substrates were respectively measured by sessile drop method under Ar atmosphere at 1550 °C. The dissolution of the MM substrate and the slag penetration behavior were investigated by combining the theoretical calculation of the FactSage thermodynamic software with the examination of SEM-EDS. The results show that MM substrate had a better slag resistance than FM substrate. The final apparent contact angles (θ f) of slags with the CaO/SiO 2 values of 3, 5 and 11 on MM substrate were 15.8°, 21.4°, and 9.2°, respectively, and that with the MgO content of 3, 6 and 9 mass% were 11.1°, 14.2°, and 52.5°, respectively. The larger the CaO/SiO 2 value of the slag, the more beneficial it was to slowing down the dissolution of MM and FM substrates; the original slag with MgO was also beneficial to lessening the dissolution of the MM substrate, which was better than that with a high CaO/SiO 2 value. The formation of MA could inhibit the slag from penetrating. In addition, for slags with different CaO/SiO 2 values, the effects of surface tension and viscosity on slag penetration were more significant than that of contact angle; for slags with different MgO contents, the effect of contact angle on slag penetration was more significant than those of surface tension and viscosity. [ABSTRACT FROM AUTHOR]

A transient three-dimensional comprehensive numerical model was established to study ion transport caused by diffusion, convection, and electro-migration in the electro-refining process for scrap-metal recycling. The Poisson–Nernst–Planck equations were used to define ion transport within the electrolyte, while the Naiver–Stokes equations and the energy equation were employed to describe fluid flow and heat transfer. In addition, the Butler-Volmer formulation was used to represent the kinetics of the electrochemical reaction. The comparison between the measured and simulated data indicates the reliability of the model. Under the action of diffusion and electro-migration, the positive copper ion moves from the anode to the cathode, while the negative sulfate ion migrates in the opposite direction. The distribution of the ion concentration, however, greatly changes if the fluid flow is taken into account. The ion concentration around the anode and the rate of the electrochemical reaction that occurs at the anode surface are reduced by the fluid flow. The proposed computational framework offers a valuable basis for future research and development in the field of scrap-metal recycling technology. [ABSTRACT FROM AUTHOR]

The effect of vacuum treatment on the cleanliness of low Ti steel treated with low basicity refining slag was studied by analyzing the change of oxygen content and inclusions characteristics in the steel after the interaction between different basicity slags and GCr15 bearing steels and after vacuum treatment. The results show that the oxide inclusions in the steel are mainly MgO·Al 2 O 3 after slag-steel interaction. The low basicity slag refining is beneficial for decreasing the harm of TiN inclusions due to the better low Ti content control. However, the oxygen content and the number of inclusions in the steel increase with the decrease of slag basicity (CaO/SiO 2 mass ratio), which means that the decrease in the basicity is disadvantageous to the cleanliness of steel. Typical inclusions in the steel transform into smaller MgO inclusions and MgS–MgO-(MnS) composite inclusions after vacuum treatment, and the oxygen content of steel is decreased to the same level. Furthermore, the size and number density of inclusions are significantly decreased after the vacuum treatment. It indicates that the combined process of low basicity slag refining and vacuum carbon deoxidation can realize the TiN inclusion control and cleanliness improvement of GCr15 bearing steel. • Low basicity slag refining is beneficial for reducing the harm of TiN inclusions on the performance of bearing steel. • Vacuum carbon deoxidization can significantly improve the cleanliness of the liquid steel. • TiN inclusion and cleanliness control of bearing steel can be realized by low basicity slag refining and vacuum treatment. [ABSTRACT FROM AUTHOR]

Segregation of interface elements is the main factor affecting the corrosion activity of microareas around Al2O3 inclusions rather than galvanic corrosion. In this work, the effects of segregation of Cu, V, Ni, Mo, B, and P elements on the interfacial bonding strength and microareas corrosion activity around Al2O3 inclusions are analyzed in detail using 3D atomic probe and first‐principles calculations. In the results, it is shown that Cu, V, Mo, B, and P elements reduce the stability of the α‐Fe/Al2O3 interface. In addition, the segregation of Cu, V, Mo, B, and P elements at the interface also enhances the adsorption capacity of Cl and ultimately improves the microarea corrosion activity around Al2O3 inclusions. Ni element can enhance the stability of α‐Fe/Al2O3 interface, and the segregation of Ni element at the interface weakens the adsorption capacity of Cl and ultimately reduces the microarea corrosion activity around Al2O3 inclusions. [ABSTRACT FROM AUTHOR]

Novel diagnostic tools are a major challenge for brucellosis research, especially in developing countries. Herein, we established a handheld quantum dot (QD) immunochromatographic device for the fast detection of brucellosis antibodies in the field. Total bacterial protein extracted from Brucella 104M served as labelling and coating antigen. QD labelling and immunochromatography methods were used to optimise reaction conditions, labelling conditions, reaction temperature and storage temperature. QD test strips were employed to test brucellosis serum to determine their sensitivity, specificity and stability. Test strips were compared with Rose Bengal test, standard agglutination test and colloidal gold immunochromatographic assay. Labelled Brucella total protein displayed good specificity and no cross-reactivity. The concentration of labelled total bacterial protein was 3.9 mg/ml, the coating concentration was 2.0 mg/ ml, and the serum titre with the lowest detection sensitivity was 1:25. The optimal reaction time for the test strip was 25−30°C. The test strip was stable after storage at room temperature and the repeatability was high, with a coefficient of variation of 4.0%. After testing 199 serum samples, the sensitivity of the QD test strip was 98.53%, the specificity was 93.57%, and the coincidence rate with the standard agglutination test was 96.98%. The developed QD immunochromatographic method can be used for rapid detection and preliminary screening of brucellosis in the field. Author summary: Brucellosis is a neglected infection that has a widespread geographic distribution. Based on an evaluation from the World Health Organization (WHO), brucellosis cases have been reported in more than 170 countries with about 500,000 new cases being reported each year. However, the actual number of brucellosis patients is much higher, and it is believed to be approximately 10–25 times the number of reported cases. This big discrepancy between the reported rate and the actual incidence rate is largely due to misdiagnosis and underdiagnosis, especially in endemic areas. In recent years, considerable effort has been mobilized toward the development of rapid, reliable field diagnostic assays and molecular diagnostic approaches. In this study, we established a handheld quantum dot (QD) immunochromatographic device for the fast detection of brucellosis antibodies in the field. This QD test strip does not require extensive laboratory infrastructure or technical expertise, and has high sensitivity (98.53%) and specificity (93.57%), as well as a high coincidence rate (96.98%) with SAT. This new tool is expected to provide fast and simple point-of-care testing at county-level clinics and CDC labs. [ABSTRACT FROM AUTHOR]

Gold nanoparticles-based molecular beacon (Au NPs-MB), due to its extraordinary highly-quenching efficiency for fluorophores, has been extensively investigated and widely used for bioimaging and bioassay. However, apart from irreversible aggregation during the "aging" step, the preparation of Au NPs-MB often suffers from relatively poor salt stability, limiting its further in vivo application. Herein, Au NPs decorated magnetic microbeads was developed to construct a novel magnetic MB for DNA assay, which not only totally solved the aggregation problem of Au NPs, but also exhibited robust stability in buffer solution. Most importantly, the fluorescence signal of each microbeads could be collected individually, realizing single microbeads-based DNA imaging, and the detection limit for target DNA could reach 0.1 nM with the detection range of 0.2–20 nM. More importantly, because the magnetic microbeads with three sizes could be readily distinguished by flow cytometry, the employed three types of hairpin DNA probes can be labelled with the same dye FITC without fluorescence cross-interference. Therefore, multiplexing detection of tumor-suppressor genes (p16, p21 and p53) could be readily realized by using size-encoded magnetic microbeads pre-functionalized with corresponding probe DNA illustrating the potential of this method in multiplexing bioassay applications. Image 1 • Magnetic microbeads-based molecular beacon was developed for DNA detection. • Three-plex detection of tumor-suppressor genes (p16, p21 and p53) was realized simply by three size-encoded Au NPs-MB. • Single Au NPs decorated magnetic microbead-based molecular beacon for DNA imaging was realized. • Au NPs decorated magnetic microbeads-based molecular beacon exhibited robust stability in buffer solution. [ABSTRACT FROM AUTHOR]

In this work, the novel Al 2 O 3 -based ceramic filter prepared by replacing dense Al 2 O 3 raw material with microporous corundum-spinel raw material is proposed and enhanced. The effects of nano-Al 2 O 3 powder content (0, 2.5, 5 and 7.5 wt%) on the rheological properties of the slurries, microstructures, pore characteristics and mechanical properties of the filters were investigated. When the nano-Al 2 O 3 powder content increased from 0 to 5 wt%, the rheological properties of the slurries were optimized, resulting in a larger thickness diameter and uniform distribution of the filter skeleton. The nano-Al 2 O 3 powder with a high reactivity accelerated the diffusion mass transfer rate of ions and increased the sintering driving force, thus promoting the development and growth of the spinel grains. It also led to the formation of more spinel neck connections between the microporous corundum-spinel particles, which enhanced the cold compressive strength and thermal shock resistance of the filters, while the pore size slightly increased due to the spinel volume expansion between the particles. When the nano-Al 2 O 3 powder content further reached 7.5 wt%, the yield stress of the slurry increased markedly due to the agglomeration phenomenon, leading to an uneven distribution of the filter skeleton and a lower cold compressive strength of the filter. Overall, the mechanical properties of the novel Al 2 O 3 -based ceramic filters were greatly enhanced by the addition of 5 wt% nano-Al 2 O 3 powder. The filter skeleton had a bulk density of 2.19 g/cm3 and an apparent porosity of 41.8%. The novel Al 2 O 3 -based ceramic filter also exhibited a high cold compressive strength of 2.37 MPa and an excellent thermal shock resistance. It contained a rougher surface structure compared to existing filters and has the potential for better purification efficiency on molten metal in the future. [ABSTRACT FROM AUTHOR]

Abstract The mechanism of inclusion-induced initial pitting corrosion of Al-Ti-Ca complex deoxidized steel with Ce treatment was studied by the experimental investigation and theoretical calculation. To figure out which phases of complex inclusion containing different components induced initial pitting corrosion, the scanning electron microscope (SEM) analysis, the continuous immersion experiments and density functional theory (DFT) calculation were conducted. Two types of inclusions and different pit morphologies were observed. The pit initially occurred at the sulfide inclusions (MnS and Ce 2 O 2 S) rather than the steel matrix due to the lower the electronic work function (EWF) of this compound compare to the steel matrix and other phases. In addition, the Ce-rich inclusion possessed the higher pitting corrosion resistance than the same type of inclusions. Finally, a schematic diagram was established to explain the mechanism of the different inclusions in initiating and proceeding pitting corrosion. Highlights • The xCaO-yAl 2 O 3 -TiN-MnS inclusions in Ce-free steel were modified to CeAlO 3 -Ce 2 O 2 S inclusions in the Ce-bearing steel. • The pitting corrosion initiates in the sulfide inclusions which have the lowest EWF in both steels. Besides, the Ce-rich inclusion, by contrast, had higher EWF than xCaO-yAl 2 O 3 -TiN-MnS inclusions. [ABSTRACT FROM AUTHOR]

Abstract BiCuSeO is a kind of promising oxide-based thermoelectric material with special natural superlattice structure. Herein, the effects of Er doping and modulation doping on the thermoelectric properties of BiCuSeO have been investigated. The results indicate that Er doping can tune the Fermi level, widen the band gap, reduce the energy offset between the heavy band and the light band, and then greatly improve the electrical conductivity, power factor and ZT. Modulation doping based on Er doping can increase carrier concentration and power factor significantly while maintaining high carrier mobility. Meanwhile, due to the special heterostructure of the modulation doping sample, the phonon scattering is greatly enhanced, and the corresponding lattice thermal conductivity is significantly reduced. Finally, the maximum ZT value reaches 0.99 for the modulation doped Bi 0.92 Er 0.08 CuSeO bulk at 873 K, which was ~1.8 times as that of the pristine BiCuSeO sample. [ABSTRACT FROM AUTHOR]

Abstract Bi 1- x Pb x Cu 1- x Ni x SeO (x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) BiCuSeO based ceramics have been prepared by mechanical alloying (MA) and resistance pressing sintering (RPS) process. The effects of Pb/Ni doping and 3D modulation doping on the thermoelectric properties have been investigated systematically. For Pb doping, it can tune the Fermi level and promote the band convergence, decreasing the band gap and significantly enhancing the carrier concentration. Besides, it contributes to higher effective mass and Seebeck coefficient due to the delocalized 6s orbitals from the lone pair electrons. For Ni doping, Ni ions could enhance Seebeck coefficient. The results indicates that the substitution of Pb at Bi site and Ni at Cu site resulted in the significantly increase of electrical conductivity and power factor. Based on this, 3D modulation doping led to the simultaneous increase of the electrical conductivity and power factor. The maximum power factor of the modulation doped sample (Bi 0.90 Pb 0.10 Cu 0.90 Ni 0.10 SeO) reached 0.64 mW m−1 K−2, and the maximum ZT value reached 1.08, which is 1.3 and 1.0 times higher than those of the undoped sample, respectively. Graphical abstract Pb/Ni doping combined with modulation doping led to the great increase of BiCuSeO based ceramics(Bi 1- x Pb x Cu 1- x Ni x SeO, x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) fx1 Highlights • Pb/Ni doping led to the great increase of carrier concentration and electrical conductivity. • Modulation doping based on Pb/Ni doping increases the electrical conductivity further. • The highest ZT is 1.08 for the modulation doped sample at 873 K. [ABSTRACT FROM AUTHOR]

The surface oxidation weight gains on 7.8 wt% Cr-containing stainless steel at different temperatures were studied by thermogravimetric analysis and scanning electron microscope (SEM) equipped with energy-dispersive spectroscopy (EDS). The results show that there are two layers of oxide scales covering the surface of steel matrix after 100 min high-temperature oxidation. The inner oxide scale consists of (Fe, Cr) oxide and the outer oxide scale is composed of Fe oxide due to the stronger affinity of Cr with O. The growth of outer oxide scale is dominated by the combined effects of chemical reaction rate and mass transfer. Based on the study of the oxidation kinetics at different temperatures, a prediction model for surface oxidation weight gain on 7.8 wt% Cr-containing stainless steel electrode during electroslag remelting is acquired, providing a reference for the determination of the amount of deoxidiser added into the molten slag during electrode remelting. [ABSTRACT FROM AUTHOR]

Here, Bi 1- x Ba x CuSe 1- x Te x O ( x  = 0, 0.02, 0.04, 0.06, 0.08, 0.10) ceramics have been prepared by mechanical alloying (MA) and resistance pressing sintering (RPS) process. The effects of Ba/Te doping on the thermoelectric properties have been investigated systematically. For Ba doping, it can tune the Fermi level and promote the band convergence, decreasing the band gap and significantly enhancing the carrier concentration; for the Te doping based on Ba doping, it can profoundly reduce the difference of electronegativity in (Cu 2 Se 2 ) 2- layer, increase bond covalency, and then increase the electrical conductivity. The results indicate that the substitution of Ba/Te resulted in significant increases of electrical conductivity and power factor. Based on this, modulation doping leads to the simultaneous increase of the electrical conductivity and Seebeck coefficient. Finally, the maximum power factor of 0.98 mW m −1 K −2 and ZT value of 1.17 were obtained for the modulation doped Bi 0.90 Ba 0.10 CuSe 0.90 Te 0.10 O bulk, which were ~ 3.5 and ~ 2.2 times respectively as those of the pristine BiCuSeO ceramic. [ABSTRACT FROM AUTHOR]

Abstract The layered oxyselenide BiCuSeO thermoelectric ceramics are attracting much scientific attention for its excellent thermoelectric properties. Herein, Bi 1- x Sb x CuSe 1- x Te x O ( x = 0, 0.01, 0.02, 0.04, 0.06, 0.08) ceramics have been prepared by ball milling (BM) and resistance pressing sintering (RPS) process. The effects of Sb/Te doping and grain size on the thermoelectric/mechanical properties are investigated systematically. For the former, it can tune the Fermi level and promote the band convergence, decreasing the band gap and concurrently enhancing the carrier concentration; for the latter, it can profoundly modify microstructure into an all-scale hierarchical architecture to scatter phonons with broad range of mean free paths, effectively reducing the lattice thermal conductivity. The results indicates that the substitution of Sb/Te resulted in the significantly increase of electrical conductivity and power factor, and BM effectively reduces the grain size to ~ 387 nm in the sample after sintering, which leads to a decrease in the thermal conductivity and an increase in the electrical conductivity. The maximum power factor of 0.72 m Wm−1 K−2 and ZT value of 1.19 were obtained for Bi 0.92 Sb 0.08 CuSe 0.92 Te 0.08 O with BM time = 16 h at 873 K, which was ~ 2.7 and ~ 2.2 times as that of the pristine BiCuSeO ceramic. Graphical abstract Sb/Te doping combined with grain refining led to the great increase of BiCuSeO based ceramics(sample 0–3 stand for ball milling time=5 h, 8 h, 12 h 16 h, respectively) fx1 [ABSTRACT FROM AUTHOR]

The exploration of effective spinal cord injury (SCI) healing still remain a great challenge due to the high morbidity, complex pathology and unclear targets. Human umbilical cord mesenchymal stem cells (hucMSC) play an important role in tissue regeneration. However, transplanting stem cells has a potential risk of teratogenicity. Recent studies have suggested that exosomes secreted by stem cells may contribute to tissue injury repair. We hypothesized that the application of hucMSC derived exosomes may be a potential way for SCI treatment. Our studies showed the hucMSC derived exosomes with a mean particle size of 70 nm could effectively trigger the bone marrow derived macrophage (BMDM) polarization from M1 to a M2 phenotype. In vivo studies demonstrated that the hucMSC derived exosomes could improve the functional recovery after SCI through down-regulation of the inflammatory cytokines, such as TNF-α, MIP-1α, IL-6 and IFN-γ. Collectively, our findings indicated that hucMSC derived exosomes could facilitate spinal cord injury healing via attenuating the inflammation of the injury region. Our results provided a new perspective and therapeutic strategy for the use of hucMSC derived exosomes in soft tissue repair. [ABSTRACT FROM AUTHOR]

The interaction between slag and GCr15 steel under argon and vacuum were investigated by laboratory experiments. The results show that the maximum and average size of inclusions, and the proportion of large inclusions decrease after slag-steel interaction. Compared with the test under argon, inclusion size of the steel in the test under vacuum is smaller and more uniform, which is attributed to that vacuum promotes the reaction of C and O in molten steel to form CO. The La content increase from 0 to 0.0022 wt% in the steel processed by La 2 O 3 containing slag after for 5 min holding at 1873 K under 0.5 kPa. Thermodynamic calculation reveals that the La 2 O 3 in molten slag can be reduced by dissolved C in liquid steel to form dissolved La under vacuum due to the relatively higher carbon content of GCr15 steel and appropriate vacuum condition. The microstructure and primary carbides of the tested steel under vacuum are finer than that under argon. The present study provides a theoretical basis for the homogenized La treatment of GCr15 steel under vacuum, which shows a promising prospect in vacuum electroslag remelting of high-end bearing steel. • Proposed a novel method for on homogenized La treatment of GCr15 steel. • The La treatment by interaction between La 2 O 3 containing slag and dissolved C in steel under vacuum is feasible. • The distribution of dissolved La in liquid steel by this method would be even due to the even distribution of reactans. [ABSTRACT FROM AUTHOR]

The BiCuSeO based ceramics have been prepared by mechanical alloying (MA) and resistance pressing sintering (RPS) process. The effects of the parameters of annealing, ball milling and sintering on the microstructure, thermoelectric properties, and mechanical properties are investigated systematically. The results indicates that the samples prepared by MA exhibit higher carrier concentration due to higher Cu vacancies concentration, smaller grain size resulting in stronger phonon scattering, and correspondingly higher thermoelectric properties than those prepared by annealing. By prolonging milling time and increasing ball milling strength, it can further refine grains, increase the carrier concentration, enhance phonon scattering and further improve thermoelectric properties. Coupled with Ca/Pb doping, the electrical conductivity at room temperature increased to 445 Scm −1 . The total thermal conductivity is below 0.90 Wm −1 K −1 in the whole measured temperature range, which is attributable to the increased defects and gain boundaries. The maximum power factor of 0.75 mWm −1 K −2 and ZT value of 1.15 were obtained for the Bi 0.84 Ca 0.08 Pb 0.08 CuSeO with BM time ( t ) = 16 h at 873 K. [ABSTRACT FROM AUTHOR]

The layered oxyselenide BiCuSeO thermoelectric ceramics are attracting more and more attention due to intrinsically low thermal conductivity. In this work, Bi 1−x−y Ba x Pb y CuSeO (x = y = 0, 0.01, 0.02, 0.04, 0.06, 0.08; x = 0, y = 0.08; x = 0.08, y = 0) bulks have been prepared by mechanical alloying (MA) and resistance pressing sintering (RPS) process, and the effects of Ba/Pb doping on the thermoelectric properties and Vickers hardness of p-type BiCuSeO ceramics have been investigated systematically. The results indicated that the substitution of Bi 3+ by Ba 2+ /Pb 2+ resulted in the significantly increase of electrical conductivity and power factor due to the introduction of the carriers into the conductive (Cu 2 Se 2 ) 2− layers as the result of the introduction of negative charge into the carrier-storaging (Bi 2 O 2 ) 2+ layers. Specifically, the room temperature electrical conductivity significantly increases from ∼8 Scm −1 for pristine BiCuSeO to ∼244 Scm −1 for Bi 0.92 Ba 0.04 Pb 0.04 CuSeO, and further up to ∼443 Scm −1 for Bi 0.84 Ba 0.08 Pb 0.08 CuSeO. The maximum power factor of 0.66 mWm −1 K −2 and dimensionless figure of merit (ZT) value of 1.01 were obtained for the Bi 0.88 Ba 0.06 Pb 0.06 CuSeO at 873 K. [ABSTRACT FROM AUTHOR]

To clarify the interaction mechanism between distinct tundish gunning materials (GM) and liquid steel, two kinds of gunning materials, namely MgO, Al2O3 GM, were tested. SEM, EDS, XRD and chemical analysis were carried out for steel and GM to investigate the change of chemical composition of steel in contact with GM and the interface microstructure between steel and GM after high temperature holding experiments. The steel cleanliness in terms of inclusion number density, size and size distribution was evaluated. It was found that the reducible component, low-melting-point phases and the pores in GM were passageway for steel penetration. The Al2O3 GM was less prone to steel penetration due to its poor wetting and the dense transition layer. MgO GM provided more oxygen and showed a stronger oxidizing capacity due to its higher content of reducible oxides (10.5 wt.% SiO2+2 wt.% Fe2O3). The use of Al2O3 GM resulted in an improved steel cleanliness and consequently could be a promising refractory in the tundish lining. [ABSTRACT FROM AUTHOR]

Titanium‐bearing (Ti‐bearing) microalloyed steels have high strength and toughness by grain refinement effect of carbonitride precipitates. However, they can induce surface cracks of continuous casting slab when the Ti alloyed content is high. A microalloyed steel with Ti content (0.10–0.15 wt%) is carried out by thermalmechanical simulator over 600–1350 °C to analyze hot ductility evolution mechanism. Fracture surface morphology, phase transition, and behavior of precipitates of the tensile samples are investigated by experimental detection and thermodynamic calculation. The ductility–temperature curves show that the third brittle temperature range is 600–890 °C, which is mainly attributed to the thin proeutectoid ferrite film and precipitated titanium carbonitride particles, widening the embrittlement temperature ranges through of steel. In addition, the tensile samples at 890–1350 °C have good hot ductility, indicating the dynamic recrystallization of deformed austenite can trigger grain boundaries migration away from cracks and avoid the side effect of the Ti (C,N) particles on hot ductility. The first brittle temperature range of 1350 °C‐melting point is mainly ascribed to the partial melting of the grain boundaries with element segregation of sulfur and phosphorus, and microporosity loose among dendrites. [ABSTRACT FROM AUTHOR]

As the best oxide based thermoelectric materials, the BiCuSeO compounds with very low lattice thermal conductivity and high figure of merit have been widely investigated because of the good thermal/chemical stability, low price and environmental friendliness. In this paper, the Bi 1-x Sb x CuSeO ( x = 0, 0.005, 0.01, 0.02, 0.05, 0.08) oxychalcogenides were prepared by mechanical alloying (MA) and resistance pressing sintering (RPS) process in order to improve the thermoelectric properties. The effect of Sb doping on the microstructure and thermoelectric properties of p-type BiCuSeO ceramic has been investigated in detail. To analysis the change rule of the thermoelectric properties of Bi 1-x Sb x CuSeO due to Sb replacing Bi site, the lattice structure and electronic behavior of Bs CuSeO ( Bs = Bi or Sb) were calculated and simulated, respectively. The band gap of Bs CuSeO has been reduced from 0.478 eV to 0.329 eV, and the bond length of Cu/Bi-Se has been decreased, the hole pocket in the band structure has been deeper, and the peaks of Cu/Se orbitals in the decomposed partial density of states have been broadened after Bi site was replaced by element Sb, which resulted in the significant increase of carrier concentration and electrical conductivity, while still keep a relatively high Seebeck coefficient and low thermal conductivity. The maximum power factor of 0.36 mWm −1 K −2 and ZT value of 0.73 were obtained for the Bi 0.95 Sb 0.05 CuSeO at 873 K, which was 65% higher than that of the undoped stoichiometry BiCuSeO ceramic. [ABSTRACT FROM AUTHOR]

Electro-slag refining process is widely employed in steel industry for the production of special alloys used in ocean, aeronautics, and nuclear industries. Because of the adverse effect on the ductility of metal, it is critical to remove oxygen in the process. This study established a transient three-dimensional (3D) coupled mathematical model for understanding oxygen transport behavior in the electro-slag refining process. The finite volume method was invoked to simultaneously solve mass, momentum, energy, and species conservation equations. Using the magnetic potential vector, Maxwell's equations were solved, during which the obtained Joule heating and Lorentz force were coupled with the energy and momentum equations, respectively. The movement of metal-slag interface was described through the application of the volume of fluid (VOF) technique. Additionally, an auxiliary metallurgical kinetic module was introduced to determine the electrochemical reaction rate. An experiment was then conducted to validate the model, where the predicted oxygen contents agreed with the measured data within an acceptable accuracy range. Oxygen redistribution in both fluids is clarified: its transport rate at the metal droplet-slag interface is approximately one order of magnitude larger than that at the metal pool-slag interface. Further, the oxygen content in the metal pool is shown to increase with time, while the content in the slag layer is decreased. In order to effectively remove the oxygen in the metal, one more positive electrode, which is more likely to react with the oxygen, is proposed to be added in the unit. Graphical abstract: Distributions of the electric streamlines and the phase distribution at 151.25 s with a current of 1800 A [ABSTRACT FROM AUTHOR]

The magnetic properties of the finally fabricated nonoriented FeSi steels critically depend on the microstructure and on the occurring crystallographic texture. The fabrication route comprises hot rolling, coiling and cooling, hot band annealing before cold rolling (optional), cold rolling and the final thermal treatment. As well known there is an interplay between the microstructure and texture during the various processing steps. For that reason, it is of interest to know more on the evolution of the microstructure at hot band annealing of hot band prepared in different ways. In this paper we will summarize our recent results on the evolution of microstructure during thermal annealing of hot band: thermal treatment following immediately the last pass of hot rolling or a hot band annealing as a separate processing step before cold rolling. [ABSTRACT FROM AUTHOR]

The novel cryogenic high-Mn austenitic steel weld metal with four different cerium (Ce) contents were prepared under submerged arc welding by adding cerium dioxide and calcium silicon reducing agents into the flux to refine the solidification structure and alleviate the microsegregation. The effects of the Ce element on the microstructure, inclusion, and microsegregation behavior of weld metal were systematically investigated via optical, scanning, and transmission electron microscopy and using an electronic probe micro-analyzer. The results showed that the dendrite arm spacing of high-Mn austenitic steel weld metal was significantly reduced with an increase in the Ce content from 0.018 to 0.087 wt%. The typical inclusions in the weld metal were mainly Al 2 O 3 , CeAlO 3 , Ce 2 O 3 , and Ce 2 O 2 S for the Ce content ranging from 0 to 0.087 wt%. The number density and the size distribution of effective inclusions influenced the microstructure variation. Numerous small-sized effective inclusions (Ce 2 O 3 and Ce 2 O 2 S) in the weld metal with 0.087 wt% Ce were distributed at the dendrite core, promoting the nucleation for austenite during the solidification and refining the dendrite structures. The co-segregation of Mn, C and Si occurred in the interdendritic regions. The segregation ratio of Mn, C and Si gradually decreased with the increase in Ce content, alleviating the element microsegregation. • Cerium (Ce) is effectively transitioned into the high-Mn cryogenic steel weld metal. • Numerous small-sized Ce 2 O 3 and Ce 2 O 2 S inclusions of weld metal are distributed at the dendrite core, promoting the nucleation for austenite and refining the dendritic structures. • The segregation ratio of Mn, C and Si gradually decrease with the increase of Ce content. [ABSTRACT FROM AUTHOR]

The oxygenated ZnO samples have been prepared by powder metallurgy, and ZnO is doped with high-valence Y element as electron donors. The study found that the electrical conductivity increased significantly, which is mainly due to the increase of carrier concentration upon Y doping. Y doping would widen the band gap, introduce impurity levels, and enhance the density of states near the Fermi level. The Seebeck coefficient decreases due to the increase of carrier concentration, and the power factor shows an upward trend. Due to the enhancement of phonon scattering after Y doping, the lattice thermal conductivity decreases. Finally, ZT was promoted from 0.009 of the pristine sample to 0.427 of the Y doped at 873 K. With the substitution of Y, the density of states near the Fermi level is significantly enhanced, and ZT is promoted from 0.009 of the pristine sample to 0.427 at 873 K. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: A novel electrode material for sodium-ion batteries (NIBs), Na3V2(PO4)3 with a rhombohedral, Na+ superionic conductor (NASICON)-type structure, was synthesised via a solid-state carbon-thermal reduction reaction assisted by mechanochemical activation. Electron microscopy analysis showed that the synthesised Na3V2(PO4)3 particles had an average size of 300 nm, being coated with a uniform layer of carbon 3 nm in thickness. As a cathode material, Na3V2(PO4)3/C exhibited an initial specific discharge capacity of 98.17 mAh g−1 at 0.1C for potentials ranging from 2.5 to 3.8 V. This was owing to the V3+/V4+ redox couple, which corresponded to the two-phase transition between Na3V2(PO4)3 and NaV2(PO4)3. The cathode lost 4.92% of its discharge specific capacity after 50 cycles. As an anode material, Na3V2(PO4)3/C exhibited an initial specific discharge capacity of 63.2 mAh g−1 at 0.1C for potentials ranging from 1.0 to 2.5 V. This was owing to the V2+/V3+ redox couple, which corresponded to the two-phase transition between Na3V2(PO4)3 and Na4V2(PO4)3. The anode lost approximately 5.41% of its discharge specific capacity after 50 cycles. The three-dimensional channel structure of NaV2(PO4)3 and the changes induced in its lattice parameters during the charge/discharge processes were simulated on the basis of density functional theory. [Copyright &y& Elsevier]

The vaporization and crystallization of CaF 2 –CaO–Al 2 O 3 slags with different La 2 O 3 contents for electroslag remelting were investigated by various analytical methods. The results show that the main volatiles from investigated slag within 7.4 wt% La 2 O 3 content at 1723 K are CaF 2 and AlF 3. The weight loss of CaF 2 –CaO–Al 2 O 3 -(La 2 O 3) slags decrease with increase of La 2 O 3 content in both thermo gravimetric experiment and vacuum condition. The addition of La 2 O 3 within 7.4 wt% reduces the viscosity and breaking temperature of investigated slag, and the change of viscosity is not the main reason to inhibit the fluoride vaporization. The vapor pressure of CaF 2 and AlF 3 at 1723 K decreases with increase of La 2 O 3 content because of the changes in component activity. Thus, fluoride vaporization becomes weakened. The crystalline phases of CaF 2 –CaO–Al 2 O 3 slag are 11CaO·7Al 2 O 3 ·CaF 2 and CaF 2 , while the crystalline phases of slag within 7.4 wt% La 2 O 3 content are (CaLa)Al 3 O 7 , La(AlO 3) and CaF 2. The La 2 O 3 addition can decrease the crystallization temperature of CaF 2 and prevent the precipitation of 11CaO·7Al 2 O 3 ·CaF 2. • The vaporization and crystallization of CaF 2 –CaO–Al 2 O 3 -(La 2 O 3) were analyzed by TG-DSC. • The viscosity of CaF 2 –CaO–Al 2 O 3 -(La 2 O 3) slag was measured. • The crystalline phases ((CaLa)Al 3 O 7 , La(AlO 3)) were found in CaF 2 –CaO–Al 2 O 3 -7.4wt% La 2 O 3 slag. [ABSTRACT FROM AUTHOR]

Abstract: Packing and layout problems have wide applications in engineering practice. However, they belong to NP (non-deterministic polynomial)-complete problems. In this paper, we introduce human intelligence into the computational intelligent algorithms, namely particle swarm optimization (PSO) and immune algorithms (IA). A novel human–computer cooperative PSO-based immune algorithm (HCPSO-IA) is proposed, in which the initial population consists of the initial artificial individuals supplied by human and the initial algorithm individuals are generated by a chaotic strategy. Some new artificial individuals are introduced to replace the inferior individuals of the population. HCPSO-IA benefits by giving free rein to the talents of designers and computers, and contributes to solving complex layout design problems. The experimental results illustrate that the proposed algorithm is feasible and effective. [Copyright &y& Elsevier]

In this study, niobium was added into grain-oriented silicon steels, four Nb-bearing hot-rolled bands with Nb content range from 0–0.025 wt% were prepared and a detailed study of the micro characterization (microstructure, texture and precipitates) of hot-rolled bands was carried out by various analysis methods, such as EBSD and TEM. The results indicate that the precipitates in Nb-free steel are MnS and AlN; however, in the Nb-bearing steel they are MnS, AlN and Nb(C, N). The precipitates are finer and more dispersed in Nb-bearing steel, and a stronger pining force was obtained, which contributes to the finer microstructure and less recrystallization fractions of the hot-rolled bands. A larger volume fraction and stronger intensity of Goss texture is presented in steel with 0.025 wt% Nb due to the effective inhibiting effect. However, it has little effect on the changes of microstructure and texture when the Nb content is more than 0.009 wt%. [ABSTRACT FROM AUTHOR]

In the present study, the experiments for the phosphorus equilibrium partition between CaO-SiO2-Fe tO-P2O5 slags with Na2O or K2O addition and solid pure iron foil were performed at 1573, 1623, and 1673 K, respectively. The experimental results showed that both Na2O and K2O addition can enhance the dephosphorization ability of CaO-SiO2-Fe tO-P2O5 based slags and they have similar dephosphorization ability under the same temperature and main slag composition. The phosphorous partition ratio between slag and carbon-saturated hot metal increased with the increase of basicity with a peak value in the range of R around 1.3-1.5. The phosphorous partition ratio decreased with the increasing of ( w(CaO) + w(Na2O))/ w(Fe tO) value in slags. The dephosphorization ability of CaO-SiO2-Fe tO-P2O5 based slags was relatively higher when the ( w(CaO) + w(Na2O))/ w(Fe tO) values fell in the range of 0.5-0.8. The phosphorous partition ratio decreased with the temperature increase. The linear relationships between the logarithm phosphorous partition ratio and the reciprocal of temperature were obtained for CaO-SiO2-Fe tO-P2O5 based slags with Na2O. The information provides by present study would be useful for optimization of dephosphorization in hot metal pretreatment. [ABSTRACT FROM AUTHOR]

Rare earth elements have unique outer electronic structure, variable valence, and strong chemical activity; however, their occurrence state in the rust layer and influence on the invasion state of corrosion atoms are still unclear. Herein, using a combination of experiment and first‐principles calculation, the occurrence state of La in the rust layer of low‐alloy high strength steel, the phase composition, compactness and stability of the rust layer, and the invasion state of corrosion atoms before and after La alloying are studied. The results show that La exists in the corrosion products in the form of a solute atom. La increases the concentration of corrosion‐resistant elements Cr and Mo in the rust layer but does not change the phase composition. La is conducive to stabilizing Cl atoms in α‐FeOOH and β‐FeOOH, so as to protect the steel matrix from Cl. La atoms inhibit the dissolution of Cl atoms into γ‐FeOOH and Fe3O4 structures and hinder their formation. [ABSTRACT FROM AUTHOR]

Hypoxia is a hallmark of cancer. Hypoxia-inducible factor (HIF), a master player for sensing and adapting to hypoxia, profoundly influences genome instability, tumor progression and metastasis, metabolic reprogramming, and resistance to chemotherapies and radiotherapies. High levels and activity of HIF result in poor clinical outcomes in cancer patients. Thus, HIFs provide ideal therapeutic targets for cancers. However, HIF biology is sophisticated, and currently available HIF inhibitors have limited clinical utility owing to their low efficacy or side effects. RNA helicases, which are master players in cellular RNA metabolism, are usually highly expressed in tumors to meet the increased oncoprotein biosynthesis demand. Intriguingly, recent findings provide convincing evidence that RNA helicases are crucial for the adaptive cellular response to hypoxia via a mutual regulation with HIFs. More importantly, some RNA helicase inhibitors may suppress HIF signaling by blocking the translation of HIF-responsive genes. Therefore, RNA helicase inhibitors may work synergistically with HIF inhibitors in cancer to improve treatment efficacy. In this review, we discuss current knowledge of how cells sense and adapt to hypoxia through HIFs. However, our primary focus is on the multiple functions of RNA helicases in the adaptive response to hypoxia. We also highlight how these hypoxia-related RNA helicases can be exploited for anti-cancer therapeutics. [ABSTRACT FROM AUTHOR]

Reticulated ceramic filters play an important role in the reduction of non-metallic inclusions in molten steel, which can improve the quality of steel products. In this work, periclase-magnesium aluminate spinel ceramic filters with Al 2 O 3 and TiO 2 functional coatings were fabricated by using microporous MgO powder, respectively. The effects of the functional coatings on their microstructure, properties and purification capacity on molten steel were studied. The filter with Al 2 O 3 functional coating exhibited the best mechanical properties owing to the good rheological properties of the coating slurry, as well as the formation of in-situ spinel layer connection between the Al 2 O 3 functional coating and the microporous MgO layer of the filter substrate. Compared with the filters without functional coating or with TiO 2 functional coating, the filter with Al 2 O 3 functional coating made more Al 2 O 3 inclusions deposit on the filter surface by physical adsorption due to the same chemical composition between the functional coating and inclusions, which significantly improved the adsorption capacity of filter for Al 2 O 3 inclusions in molten steel. Overall, the filter with Al 2 O 3 functional coating had the highest cold compressive strength of 1.4 MPa, a residual retention of cold compressive strength after thermal shock of 65.71 % and an efficiency of 36.56 % in reducing the total oxygen content of the steel. [ABSTRACT FROM AUTHOR]

The dissolution of Al 2 O 3 –C refractories in 45 wt% CaO-45 wt% SiO 2 -x wt% CaF 2 -(10-x) wt% Na 2 O slag was explored by the static test and thermodynamic calculation. The results show that the severe slag penetration into refractories occurs after corrosion test. With the gradual replacement of CaF 2 in slag by Na 2 O, lots of pores are found in the slag phase near the refractory/slag interface due to the formation of gaseous phase from the reaction between Na 2 O in slag and C in refractories. Compared with the slag without Na 2 O, the slag bearing 5 wt% Na 2 O does not accelerate the dissolution of refractory into slag. The possible reason is that the reaction between CaF 2 in slag and Al 2 O 3 in bricks is inhibited due to the replacement of CaF 2 in slag by Na 2 O. The dissolution of Al 2 O 3 –C refractories is faster in the slag bearing 10 wt% Na 2 O than that in the slag bearing 5 wt% Na 2 O, due to the severer Na 2 O volatilization from the reduction of Na 2 O in slag by C in refractories, which accelerates the renewal rate of boundary layer between refractories and slag phase. The results indicate that replacing part of CaF 2 in mold slag with moderate amount of Na 2 O does not aggravate the corrosion of submerged entry nozzle consisting of Al 2 O 3 –C based refractories. [ABSTRACT FROM AUTHOR]

• A simplified multi-task CNN is used for feature detection. • Features keep the same descriptor format as the ORB features. • Depth information of the RGB-D camera is adopted to construct the dense 3D map. Simultaneous Localization and Mapping (SLAM) is the basis for intelligent mobile robots to work in unknown environments. However, traditional feature extraction algorithms that traditional visual SLAM systems rely on have difficulty dealing with texture-less regions and other complex scenes, which limits the development of visual SLAM. The studies of feature points extraction adopting deep learning show that this method has more advantages than traditional methods in dealing with complex scenes, but these studies consider accuracy while ignoring the efficiency. To solve these problems, this paper proposes a deep-learning real-time visual SLAM system based on multi-task feature extraction network and self-supervised feature points. By designing a simplified Convolutional Neural Network (CNN) for detecting feature points and descriptors to replace the traditional feature extractor, the accuracy and stability of the visual SLAM system are enhanced. The experimental results in a dataset and real environments show that the proposed system can maintain high accuracy in a variety of challenging scenes, run on a GPU in real-time, and support the construction of dense 3D maps. Moreover, its overall performance is better than the current traditional visual SLAM system. [ABSTRACT FROM AUTHOR]

The microporous magnesia aggregates show a promising application prospect as tundish lining, due to the excellent thermal insulation. In this study, the effect of nano-sized Al 2 O 3 addition on the corrosion resistance of microporous magnesia aggregates against tundish slag is explored. The results show that the addition of nano-sized Al 2 O 3 deteriorates the slag resistance of microporous magnesia aggregates, which is mainly because that the apparent porosity of aggregates increases with the addition of nano-sized Al 2 O 3. Furthermore, MgO·Al 2 O 3 spinel is formed in situ at the grain boundaries of Al 2 O 3 -bearing aggregates and the dissolution of MgO·Al 2 O 3 spinel into molten slag damages the structure of aggregates. For the Al 2 O 3 -free microporous magnesia aggregates, as expected, the penetration of high basicity slag (CaO/SiO 2 = 9, mass ratio) into refractory is slighter than that of low basicity slag (CaO/SiO 2 = 4, mass ratio). But, for the Al 2 O 3 -bearing microporous magnesia aggregates, the corrosion of refractory by high basicity slag is severer. This is mainly because that MgO·Al 2 O 3 spinel is more unstable in high basicity slag. Therefore, it is not suitable to add nano-sized Al 2 O 3 for the preparation of microporous magnesia as tundish lining. [ABSTRACT FROM AUTHOR]

Thermoelectric materials have great application prospects in the fields of micro-refrigeration, waste heat utilization and catalysis, and BiCuSeO is one of the oxide thermoelectric materials with the best comprehensive thermoelectric properties at present. Herein, the dispersion of 20-nm SiC in BiCuSeO matrix has greatly increases the thermoelectric and mechanical properties of the system. SiC nanoparticles dispersed in BiCuSeO matrix can act as energy filters to increase the Seebeck coefficient, on the other hand, as phonon scattering centers to scatter the low- and mid-frequency phonons effectively to reduce the lattice thermal conductivity, combined with point defects such as Pb Bi + scattering the high-frequency phonons, thus achieving the scattering enhancement of full-frequency phonons. In addition, the mechanical strength and machinability of BiCuSeO have been improved significantly due to the dispersion strengthening effect of SiC nanoparticles. Image 1 • Nano-SiC is dispersed in BiCuSeO matrix by mechanical alloying and spark plasma sintering. • Nano-SiC can enhance the Seebeck coefficient by energy filtering effect, and enhance the power factor. • SiC dispersion achieves the scattering enhancement of full-frequency phonons and decreases thermal conductivity. • The highest ZT reached 1.32 at 873 K for 8% SiC compositing. [ABSTRACT FROM AUTHOR]

The microporous refractory with low thermal conductivity shows a promising application prospect as tundish lining. In this study, the interactions between microporous magnesia aggregates and oxide inclusions in steel were explored. The experimental results and thermodynamic calculation show that the interaction process of microporous magnesia aggregates and oxide inclusions at high temperature can be divided into dissolution, reaction and post-reaction. The microporous magnesia aggregates can absorb the inclusions in steel by reaction and liquid phase penetration. The microporous magnesia aggregates have a strong adsorption for Al 2 O 3 and TiO 2. Moreover, the microporous magnesia aggregates mainly absorb SiO 2 by penetration, but excessive SiO 2 will lead to the serious corrosion of microporous magnesia aggregates. [ABSTRACT FROM AUTHOR]

Demand for energy saving in steelmaking process, lightweight refractories have attracted great attentions for the excellent thermal insulation. Herein, the corrosion behavior of the lightweight magnesia in the high basicity tundish slag is explored, and compared with that of fused magnesia. The results show that the impurities in the fused magnesia cause more dissolution of magnesia into slag after 60 min. Different from fused magnesia, the penetration layer is found in the lightweight magnesia, where the intercrystalline CaZrO3–ZrO2 phases are dissolved by the slag. The micropores in the lightweight magnesia provide passages for slag infiltration, but also accelerate the supersaturation of slag in refractory and impede the mass transfer. Furthermore, the residual CaZrO3–ZrO2 phases in transition layer hinder the further slag infiltration. After 60 min holding, the MgO content in molten slag contacted with lightweight magnesia is lower, implying that the lightweight magnesia is the promising refractory for tundish lining. [ABSTRACT FROM AUTHOR]

A bimetallic composite roll with the cladding layer of high-speed steel (HSS) and the roll core of ductile cast iron (DCI) was manufactured by the electroslag remelting cladding (ESRC) technology, and the changes in the graphite morphology, matrix structure, and mechanical properties of the DCI core before and after the ESRC process were compared. The DCI core was first heated to a very high temperature and then cooled down to room temperature during ESRC which led to a deteriorative graphite morphology with a low spheroidisation rate, a large size, and a nonuniform distribution and also caused a solid-state phase transformation of the matrix structure from lamellar pearlite + few carbides to bainite + large amounts of carbides. Based on the changes of graphite sphericity, matrix structure, carbides content, the tensile strength and impact toughness of DCI before and after the ESRC process changed from 458 MPa, 3.02 J/cm2 to 417 MPa, 5.74 J/cm2, respectively. [ABSTRACT FROM AUTHOR]

The effect of spinel powder on the fracture behavior and mechanical properties of lightweight magnesia‐based refractories containing microporous magnesia aggregates with high apparent porosity (37.4%) were investigated by the wedge splitting test (WST) with the digital image correlation and acoustic emission. With the addition of spinel powder, lightweight magnesia spinel refractories showed a higher cold compressive strength compared with lightweight pure magnesia refractories. From the WST, the addition of spinel powder increased the specific fracture energy and characteristic length of lightweight magnesia spinel refractories, which improved the crack propagation resistance. The increased tortuosity of main crack and a higher ratio of crack propagation along the aggregates/matrix interface were main reasons for reducing the brittleness of lightweight magnesia spinel refractories. Besides, acoustic emission (AE) signal activity indicated that the propagation of pregenerated micro‐cracks by the thermal mismatch and the development of fracture progress zone were primary ways to consume energy in lightweight magnesia spinel refractories. The reduced proportion of crack propagation within aggregates was also detected by the peak frequency of AE signals in lightweight magnesia spinel refractories. For microporous magnesia aggregates with high apparent porosity (37.4%), lightweight magnesia spinel refractories also showed reduced brittleness fracture behavior than lightweight pure magnesia refractories. [ABSTRACT FROM AUTHOR]

In this study, five sets of MgO-based ceramic filters were prepared using porous MgO powder and α-Al 2 O 3 micro-powder as raw materials. The effect of α-Al 2 O 3 content on the microstructures, mechanical properties and purification efficiency of MgO-based filters were investigated via SEM, EDS, and immersion test in molten steel, etc. The results indicate that the reactive sintering between α-Al 2 O 3 and MgO promoted the formation and growth of neck connections of magnesium aluminate spinel between grains, increased the density of the filter skeleton, and decreased the pore size inside the skeleton. The higher density and smaller pore size of the skeleton, as well as the neck connection of spinel and crack deflection effect caused by magnesium aluminate spinel, comprehensively improved the strength and thermal shock resistance of MgO-based ceramic filters. Furthermore, the results from the immersion test in molten steel revealed that an appropriate amount of high-temperature liquid phase, smaller pore size, and in-situ generated spinel were beneficial for the filters to adsorb dissolved aluminum, dissolved oxygen, alumina inclusions, and secondary spinel inclusions in the steel. The filter with 20 wt% α-Al 2 O 3 had the best overall performance with a compressive strength of 2.35 MPa, a compressive strength after thermal shock test of 1.91 MPa and an efficiency of 77.3% in reducing the total oxygen content of the steel. • In this work, MgO-based ceramic filters with excellent overall performance were successfully prepared and tested by steel immersion. • The mechanical properties and purification efficiency of MgO-based filters were improved via the introduction of α-Al 2 O 3. • The effects of α-Al 2 O 3 content on the microstructures and properties of MgO-based filters were investigated. [ABSTRACT FROM AUTHOR]

The decarburisation annealing processes of Nb-bearing grain-oriented silicon steel under different conditions were conducted. The effect of nitriding and decarburisation annealing time on the carbon content, precipitates, microstructure and texture of Nb-bearing grain-oriented silicon steel were investigated by the various analysis methods. The results show that the carbon content in the steel decreases as decarburisation time increasing, and decreases below 0.003% eventually. Larger number density and smaller size of precipitates were obtained in the sample treated by nitriding before decarburisation annealing process, leading to fine and uniform microstructure, which is beneficial to obtain excellent magnetic properties for Nb-bearing grain-oriented silicon steel. The main texture types of the experimental samples were γ-fibres with a peak at {111}<112 >. The nitriding before decarburisation annealing process makes little effect on texture evolution during decarburisation annealing process. [ABSTRACT FROM AUTHOR]

In order to clarify the effect of graphite content on the corrosion behavior of MgO–C refractories immersed in MnO-rich slag, the MgO–C refractory samples bearing 5 wt%, 10 wt% and 15 wt% graphite were prepared, and exposed in the slag composed of 40 wt% CaO, 40 wt% SiO 2 and 20 wt% MnO. The results show that metallic Mn particles and (Mg,Mn)O solid solution are formed at the slag/refractories interface. Whereas, no dense layer is formed by (Mg,Mn)O solid solution at the interface. The decrease in MnO content of slag is mainly attributed to the reaction with graphite to form liquid Mn. The graphite is found in the slag, and dissolved in the form of oxidation. The poor wetting limits the contact area of graphite and slag, reducing graphite oxidation and decarburized area. The graphite does not become the passage for slag to penetrate into the refractories due to the oxidation. On the contrary, the dissolution of MgO in slag is faster than graphite, thus is mainly responsible for the degradation of refractories. As a result, MnO and MgO contents change less in the slag contacted with the refractories bearing higher graphite content. [ABSTRACT FROM AUTHOR]

The oxidation behavior and subsurface phase transformation of novel high Mn cryogenic steel Fe–(0.35–0.45)C–(0.2–0.25)Si–(25–25.8)Mn–(3–5)Cr are investigated in the temperature range of 600–1200 °C under air atmosphere. The results show that the weight gain curves of oxidation with time are in good agreement with linear equations during 90 min holding below 800 °C, implying that the interface reaction is the rate‐controlling process. Above 900 °C, the oxidation reaction kinetics is governed by the parabolic rate law due to the formation of thick oxide scale. The inner oxide scale mainly consisting of Cr oxide at 1000 °C is thicker than that at 900 °C, but the thickness of the whole oxide scale is thinner than that at 900 °C. After 90 min holding, the oxidation weight gain at 900 °C is more than that at 1000 °C, which is dominated by the combined effect of thermodynamic and kinetic factors. The Mn‐depleted zone occurs in the steel matrix epidermis, leading to the subsurface phase transformation. The γ‐Fe transforms into α‐Fe in the steel matrix epidermis, which will result in deterioration of steel properties. Protective atmosphere should be adopted for heat treatment process of the novel high Mn steel. [ABSTRACT FROM AUTHOR]

The structure, vaporization behavior and crystallization of CaF2–CaO–Al2O3 slags with different SiO2 contents for electroslag remelting were investigated by employing the TG and DSC measurements in conjunction with the Raman spectroscopy measurement for linking the macroscopic physicochemical property and microstructure information. The results show that SiO2 addition makes the depolymerized aluminate units polymerized into fully polymerized QAl4 unit and Al–O–Al complex structural groups. With the SiO2 content increasing to 6.1 mass%, the vaporization rate of fluoride increases because the SiF4 possessing higher vapor pressure is formed and the SiO2 addition can promote the formation of AlF3. As SiO2 content is further increased to 8.6 mass%, the vaporization rate of fluoride decreases because the mass transfer becomes slower. The more complex slag structure resulted from SiO2 addition dramatically decreases the crystallization temperature of the primary crystalline phase and the size of crystalline particles in the solidified slag. [ABSTRACT FROM AUTHOR]

Cu is an austenite‐forming element in duplex stainless steel, and the precipitation of Cu‐rich phase can improve the strength of the alloy. However, the role of Cu element in the corrosion resistance of stainless steel is widely controversial. Herein, the effects of different Cu content on the formation of inclusions and the pitting resistance of duplex stainless steel are studied by using potentiodynamic anodic polarization test, immersion corrosion, scanning electron microscope, and electron probe microanalysis. The results show that the pitting potential decreases significantly with the increase of Cu content, which greatly reduces its ability to resist Cl− corrosion. The reason is that Cu increases the driving force for the formation of Al‐containing oxides, which increases the number and size of Al‐containing inclusions formed in the process of melting and solidification. At the same time, Cu promotes the formation of Cr‐depleted zone, which promotes the formation of microcracks and pitting corrosion between steel matrix and inclusions in duplex stainless steel. [ABSTRACT FROM AUTHOR]