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Super-high bed sintering for iron ores:behaviors,causes and solutions of horizontal segregation on strand

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Journal of Iron and Steel Research International 2024年第7期31卷 1590-1596页

作者： Liang-ping Xu hui-bo Liu Zhong-lin Dong Qiang Zhong Yu-chao Zhao guang-hui Li School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083HunanChina

Horizontal segregation has been a constraint to the development and application of super-high bed *** eliminate the horizontal segregation of super-high bed sintering,several typical sintering machines were sampled and analyzed,and theoretical calculation was made to compare the bed depth and their differences in different areas within the mixture ***,solutions were proposed and applied to a 265 m^(2) sintering *** results showed that the horizontal seg-regation of the 265 m^(2) sintering machine was dominated by particles larger than 8 mm with horizontal segregation degree of 0.48,while 360 and 550 m^(2) sintering machines were affected by 5-8 mm and 1-3 mm particles with horizontal segregation degree of 0.27 and 0.31,*** analysis indicated the different segregation distribution results from the matching of the bed depth of each area within the mixture ***,the horizontal segregation degree not larger than 0.06 was achieved by optimizing the time parameters and the division of three zones on the 265 m^(2) sintering machine.

关键词： Super-high bed sintering Horizontal segregation Feeder Particle distribution Agglomeration

Resolution Enhancement of SOHO/MDI Magnetograms

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Research in Astronomy and Astrophysics 2024年第6期24卷 358-367页

作者： Ying Qin Kai-Fan Ji hui Liu Xiao-guang Yu Yunnan Observatories Chinese Academy of SciencesKunming 650011China university of Chinese Academy of Sciences Beijing 100049China Yunnan Key Laboratory of Solar Physics and Space Science Kunming 650216China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China

Research on the solar magnetic field and its effects on solar dynamo mechanisms and space weather events has benefited from the continual improvements in instrument resolution and measurement *** augmentation and assimilation of historical observational data timelines also play a significant role in understanding the patterns of solar magnetic field *** the realm of astronomical data processing,super-resolution(SR)reconstruction refers to the process of using a substantial corpus of training data to learn the nonlinear mapping between low-resolution(LR)and high-resolution(HR)images,thereby achieving higherresolution astronomical *** paper is an application study in high-dimensional nonlinear *** learning models were employed to perform SR modeling on SOHO/MDI magnetograms and SDO/HMI magnetograms,thus reliably achieving resolution enhancement of full-disk SOHO/MDI magnetograms and enhancing the image resolution to obtain more detailed *** this study,a data set comprising 9717pairs of data from 2010 April to 2011 February was used as the training set,1332 pairs from 2011 March were used as the validation set and 1034 pairs from 2011 April were used as the test *** data preprocessing,we randomly cropped 128×128 sub-images as the LR cases from the full-disk MDI magnetograms,and the corresponding 512×512 sub-images as HR ones from the HMI full-disk magnetograms for model *** tests conducted have shown that the study successfully produced reliable 4×SR reconstruction of full-disk MDI *** MESR model's results(0.911)were highly correlated with the target HMI magnetographs as indicated by the correlation coefficient ***,the method achieved the best PSNR,SSIM,MAE and RMSE values,indicating that the MESR model can effectively reconstruct magnetograms.

关键词： magnetic fields techniques:image processing virtual observatory tools Sun:magnetic fields

Super-high bed sintering for iron ores: inhomogeneous phenomena and its mechanism during mineralizing

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Journal of Iron and Steel Research International 2024年第8期31卷 1850-1860页

作者： hui-bo Liu Liang-ping Xu Xi-duan Yang Zhong-lin Dong Qiang Zhong guang-hui Li School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083HunanChina

The inhomogeneous sinter properties in super-high bed sintering have been reported in our previous *** inves-tigate the reasons for the inhomogeneous phenomena,detailed sampling and analysis of mixed material bed and sintered bed in super-high bed sintering plant were *** results indicated that the higher porosity and thinner dendrite of silico-ferrite of calcium and aluminum in the upper layer as well as dense structure and higher secondary hematite content in the lower layer led to the heterogeneities of mechanical strength and reduction properties exceeding 20%and 10%,*** the bed top downward,the basicity of mixed material decreased from 2.13 to 1.68 because the average particle size increased from 2.65 to 4.56 *** and fuels gathered in finer particles(-3 mm)of mixed material,and the-3 mm particles of mixed material generated more liquid phase than+3 mm *** heat input of super-high sintering bed was inhomogeneous due to the heat accumulation effect and unreasonable fuel *** inhomo-geneous sintering heat condition in sintering bed resulted in the different quantities and properties of liquid *** inhomogeneous quantities and properties of liquid phase that were influenced by inhomogeneous distribution of chemical composition,particle size,and heat input led to inhomogeneous mineralizing *** mineralizing condition is the key for homogeneous super-high bed sintering.

关键词： Iron ore Super-high bed sintering Mineralization Material segregation Heat accumulation

Atomic-scale mechanism of effect of co-separation of elements at interface of ferrite and austenite on Cr-depleted zone of duplex stainless steel

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Journal of Iron and Steel Research International 2024年第3期31卷 710-718页

作者： Yan-hui Hou Ze-kun Xu Shi-long Zhou guang-qiang Li The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Key Laboratory for Ferrous Metallurgy and Resources utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan 430081HubeiChina

Three-dimensional atom-probe tomography and first-principles calculation combined with density functional theory were used to study the effect of the co-segregation of different elements formed during the solidification process of S32205 duplex stainless steel on the Cr-depleted zone at the interface between ferrite and *** was found that the co-segregation of different elements formed during the solidification process of duplex stainless steel can also form Cr-depleted zone at the interface between ferrite and ***,Mo,Si,B,C and P atoms promote co-segregation with Cr atoms,which promotes the formation of Cr-depleted zone at the interface between ferrite and austenite in duplex stainless *** and Si strongly promote the segregation of Cr at the interface between ferrite and austenite,thereby promoting the formation of Cr-depleted zone.B,C and P elements also promote the segregation of Cr element at the interface between ferrite and austenite and the formation of Cr-depleted zone,but their effect is weaker than that of Mo and Si *** conclusions provide a new theoretical basis for improving the intergranular corrosion performance of duplex stainless steel.

关键词： Duplex stainless steel Cr-depleted zone Intergranular corrosion Co-segregation First-principles calculation

Enhancing reversible hydrogen storage performance of 2LiBH_(4)–MgH_(2)via in-situ building heterogeneous nucleation sites

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Rare Metals 2024年第9期43卷 4367-4376页

作者： Wei Chen Ya-hui Sun Tian Xu Xue-Bin Yu guang-Lin Xia Department of Materials Science Fudan UniversityShanghai 200433China

2LiBH_(4)-MgH_(2)composite is one of the most attractive reactive hydride composites with a theoretic hydrogen capacity of 10.8 wt%.However,the large nucleation restriction of MgB_(2)during the second step of dehydrogenation results in sluggish hydrogen storage kinetics and high operating temperature,which hinders its practical application as on-board hydrogen storage ***,Al3Ti doped Al nanoparticles(AT NPs)are prepared by a facile chemical reduction reaction to improve the hydrogen storage performance of 2LiBH_(4)-MgH_(2)*** the initial H_(2)desorption process,MgAlB_(4)and TiB_(2)that have identical crystal structure and low d-value mismatch with MgB_(2)resulting from the reaction between AT NPs and 2LiBH_(4)-MgH_(2)composite serve as effective nucleation sites for the formation of MgB_(2).As a result,the apparent activation energy of the two-step H_(2)desorption of AT NPs doped 2LiBH_(4)-MgH_(2)composite are notably decreased to(110.0±5.9)and(119.6±1.4)kJ·mol^(-1),which is 55.5 and 33.5 kJ·mol^(-1)lower than that of the undoped *** importantly,a reversible hydrogen storage capacity of 9.2 wt%after 10cycles of H_(2)desorption and adsorption could be achieved,corresponding to a capacity retention rate of 99%.The building of reactive bimetallic catalyst towards in situ formation of heterogeneous nucleation sites provides a new strategy for improving the hydrogen storage performance of reactive hydride composites.

关键词： Reversible hydrogen storage Reactive hydride composites Catalytic effects Heterogeneous nucleation

Super-high bed sintering for iron ores:problems ascertainment

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Journal of Iron and Steel Research International 2024年第5期31卷 1063-1070页

作者： Liang-ping Xu hui-bo Liu Yu-chao Zhao Qiang Zhong Zhong-lin Dong guang-hui Li Tao Jiang School of Minerals Processing and Bioengineering Central South UniversityChangsha410083HunanChina

Super-high bed sintering process is an important development direction of iron ore sintering for its lower emission and higher ***,there is a lack of deep understanding of the uneven quality of super-high bed sintering products,and the deterioration of reduction disintegration performance,the thickening of hearth layer and the reduction in energy-saving effect are perplexing enterprises and *** ascertain the problems of super-high bed sintering,ten sintering machines with the areas of 265,280,360,550 and 660 m^(2)and bed depth above 900 mm were sampled and *** results showed that problems were mainly shown in the unevenness of chemical composition,macrostructure,mechanical strength and metallurgical *** chemical composition exhibits severe segregation in both horizontal and vertical directions,with basicity segregation reaching as high as *** uneven macrostructure of sinter is reflected in a 10%difference in porosity and mechanical strength increase in 16%–19%along the vertical *** reducibility and reduction disintegration performance gradually deteriorate along the bed depth,with a difference of 10.5%in reducibility and 7.3%in RDI−0.5 mm(reduction disintegration index of sinter with size smaller than 0.5 mm).

关键词： Super-high bed sintering uneven sinter performance Segregation Agglomeration Iron ore

Integrating theory with the nanoreactor concept to synthesize hollow carbon sphere-encapsulated PtNi alloys for enhanced H_(2) generation

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Carbon Energy 2024年第7期6卷 150-162页

作者： Yufeng Wu Minwei Song Ziyi Zhao guang-hui Wang Changlong Wang Didier Astruc Institute of Circular Economy Faculty of Materials and ManufacturingBeijing University of TechnologyBeijingChina Key Laboratory of Biofuels Qingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of SciencesQingdaoChina ISM UMR CNRS N°5255Universitéde BordeauxTalence CedexFrance

The rational design of efficient bimetallic nanoparticle(NP)catalysts is challenging due to the lack of theoretical understanding of active components and insights into the mechanisms of a specific ***,we report the rational design of nanoreactors comprising hollow carbon sphere-confined PtNi bimetallic NPs(PtNi@HCS)as highly efficient catalysts for hydrogen generation via ammonia borane hydrolysis in *** both density functional theory calculations and molecular dynamics simulations,the effects of an active PtNi combination and the critical synergistic role of a hollow carbon shell on the molecule diffusion adsorption behaviors are *** isotope effects and theoretical calculations allow the clarification of the mechanism,with oxidative addition of an O-H bond of water to the catalyst surface being the rate-determining *** remarkable catalytic activity of the PtNi@HCS nanoreactor was also utilized for successful tandem catalytic hydrogenation reactions,using in situ-generated H_(2) from ammonia borane with high *** concerted design,theoretical calculations,and experimental work presented here shed light on the rational elaboration of efficient nanocatalysts and contribute to the establishment of a circular carbon economy using green hydrogen.

关键词： ammonia borane hydrogen nanoalloy nanoreactor solid catalyst

Effect of Mn addition on microstructure and mechanical properties of GX40CrNiSi25-12 austenitic heat resistant steel

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China Foundry 2024年第3期21卷 205-212页

作者： Guan-yu Jiang Meng-wu Wu Xiao-guang Yang hui Wang Yu-yuan Zhu Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070China Hubei Longzhong Laboratory Xiangyang 441000HubeiChina Wescast Industries(China)Co. Ltd.Wuhan 430100China

Three types of steels were designed on the basis of GX40CrNiSi25-12 austenitic heat resistant steel by adding different Mn contents(2wt.%,6wt.%,and 12wt.%).Thermodynamic calculation,microstructure characterization and mechanical property tests were conducted to investigate the effect of Mn addition on the microstructure and mechanical properties of the austenitic heat resistant *** show that the matrix structure in all the three types of steels at room temperature is completely *** NbC and M_(23)C_(6)precipitate at grain boundaries of austenite *** the increase of Mn content,the number of carbides increases and their distribution becomes more *** the Mn content increases from 1.99%to 12.06%,the ultimate tensile strength,yield strength and elongation increase by 14.6%,8.0%and 46.3%,*** improvement of the mechanical properties of austenitic steels can be explained by utilizing classic theories of alloy strengthening,including solid solution strengthening,precipitation strengthening,and grain *** increase in alloy strength can be attributed to solid solution strengthening and precipitation strengthening caused by the addition of *** improvement of the plasticity of austenitic steels can be explained from two aspects:grain refinement and homogenization of precipitated phases.

关键词： austenitic heat resistant steel manganese microstructure mechanical properties

Regulations of m^(6)A and other RNA modifications and their roles in cancer

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Frontiers of Medicine 2024年第4期18卷 622-648页

作者： Xin-hui Chen Kun-Xiong Guo Jing Li Shu-hui Xu huifang Zhu guang-Rong Yan Biomedicine Research Center Guangdong Provincial Key Laboratory of Major Obstetric DiseaseGuangdong Provincial Clinical Research Center for Obstetrics and GynecologyState Key Laboratory of Respiratory Diseasethe Third Affiliated Hospital of Guangzhou Medical UniversityGuangzhou510150China

RNA modification is an essential component of the epitranscriptome,regulating RNA metabolism and cellular *** types of RNA modifications have been identified to date;they include N^(6)-methyladenosine(m^(6)A),N^(1)-methyladenosine(m1A),5-methylcytosine(m5C),N^(7)-methylguanosine(m^(7)G),N^(6),2′-O-dimethyladenosine(m^(6)Am),N4-acetylcytidine(ac^(4)C),*** modifications,mediated by regulators including writers,erasers,and readers,are associated with carcinogenesis,tumor microenvironment,metabolic reprogramming,immunosuppression,immunotherapy,chemotherapy,etc.A novel perspective indicates that regulatory subunits and post-translational modifications(PTMs)are involved in the regulation of writer,eraser,and reader functions in mediating RNA modifications,tumorigenesis,and anticancer *** this review,we summarize the advances made in the knowledge of different RNA modifications(especially m^(6)A)and focus on RNA modification regulators with functions modulated by a series of factors in cancer,including regulatory subunits(proteins,noncoding RNA or peptides encoded by long noncoding RNA)and PTMs(acetylation,SuMOylation,lactylation,phosphorylation,etc.).We also delineate the relationship between RNA modification regulator functions and carcinogenesis or cancer ***,inhibitors that target RNA modification regulators for anticancer therapy and their synergistic effect combined with immunotherapy or chemotherapy are discussed.

关键词： RNA modification writers erasers readers regulatory subunits PTMs cancer