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A review on prediction of casting defects in steel ingots:from macrosegregation to multi-defect model

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Journal of Iron and Steel Research(International) 2022年第12期29卷 1901-1914页

作者： Jun li Xiao-wei Xu Neng Ren Ming-xu Xia jian-guo li School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Key Laboratory of Advanced High-Temperature Materials and Precision Forming Shanghai 200240China

Due to the nature of the solute redistribution,the reduction in the solidification rate with time in a square root relationship,and the multiphase melt flow during the solidification,casting defects such as macrosegregation,shrinkage cavity,and porosity will inevitably occur in the steel ingot and intensify with the increase in ingot size.These defects directly affect the performance of the final product and severely restrict the choice of subsequent thermal processing methods and process windows.Therefore,the solidification defects including macrosegregation,shrinkage/porosity,and inclusions encountered in the preparation of large steel ingots and their formation mechanisms were reviewed.The development progress and the latest development of the macrosegregation model for steel ingots were introduced in detail,especially the latest progress in the coupling prediction of macrosegregation and shrinkage as well as macrosegregation and inclusions.Some methods to reduce macrosegregation of ingots were discussed as well.Finally,a new casting method called layered casting was introduced in detail.This method can effectively improve the uniformity of the macrostructure and reduce the macrosegregation of the large ingots and therefore is a promising method for preparing large ingots with high homogeneity.

关键词： Steel ingot Macrosegregation Numerical modeling Multiphase model Solidification defect

Characteristics of Altered Ilmenite in Uranium-Bearing Sandstone and Its Relationship with Uranium Minerals in the Northeastern Ordos Basin

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Journal of Earth Science 2022年第2期33卷 342-357页

作者： Lulu Chen Yin Chen Hu guo Hualei Zhao Peisen Miao jian-guo li Xiaoxi Feng Rengan Yu Chao Tang Tianjin Center China Geological SurveyTianjin 300170China State Key Laboratory of Nuclear Resources and Environment East China University of TechnologyNanchang 330013China Key Laboratory of Uranium Geology China Geological SurveyTianjin 300170China North China Center of Geoscience Innovationy Tianjin 300170 China Cores and Samples Center of Natural Resources Beijing 100192China

In recent years,the close relationship between uranium and Ti-Fe oxides in the sandstonetype uranium deposits has been extensively recognized.However,the altered characteristics of ilmenite and its relationship with uranium enrichment still remain unclear.With this paper based on heavymineral sorting of uranium ore selected from the Tarangaole-Nalinggou deposit in the northeastern Ordos Basin,electron probe,backscattering image,energy spectrum and scanning electron microscopy were systematically performed.The ilmenite in the sandstone can be divided into four groups,including unaltered,weakly altered,moderately altered,and strongly altered ilmenite.The alteration of ilmenite in uranium ores is notably more intense than that of the surrounding rocks.In addition,weakly,moderately,and strongly altered ilmenite associated with uranium minerals in uranium ores demonstrate that the more intensity ilmenite altered,the closer its relationship with uranium minerals is.The ilmenite has likely been somewhat altered before mineralization,and the alteration intensifies by later exposure related to an oxygencontaining fluid.The alteration mechanism comprises a process of competitive diffusion between Fe^(2+)and O_(2)-ions.In the early stage,Fe ions was mainly diffused on the particle surface.Subsequently,diffusion of O ions into the particles began to be dominate.Most of the leached iron is stripped or carried away by fluid.In an alkaline and reductive environment,the remaining iron is reduced to form the surrounding pyrite,and TiO_(2)in a form of titanium sol recrystallizes(i.e.,anatase).Backscattering images show that uranium and altered ilmenite are close in space.Coffinite is often distributed along the edges of altered ilmenite as burrs in shape.Colloidal or knitted coffinite associated with anatase is formed in the voids of altered ilmenite.The chemical composition of altered ilmenite varies considerably from the core to edge,and the mineral assemblage sequence is from girdle with ilmenite,to leucosphenite,to anatase,and

关键词： Ordos Basin Tarangaole-Nalinggou uranium deposit altered ilmenite uranium occurrence enrichment of uranium ore deposit geology

Size distribution of inclusions in 12%Cr stainless steel with a wide range of solidification cooling rates

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International Journal of Minerals,Metallurgy and Materials 2015年第11期22卷 1157-1162页

作者： Han-song Yu jian-guo li School of Materials Science and Engineering Shanghai Jiao Tong University

The effect of solidification cooling rate on the size and distribution of inclusions in 12%Cr stainless steel was investigated. A wide range of solidification cooling rates（from 0.05 to 106 K·s^-1） was achieved using various solidification processes, including conventional casting, laser remelting, and melt spinning. The size and distribution of inclusions in the steel were observed and statistically collected. For comparison, mathematical models were used to calculate the sizes of inclusions at different solidification cooling rates. Both the statistical size determined from observations and that predicted from calculations tended to decrease with increasing cooling rate; however, the experimental and calculated results did not agree well with each other at excessively high or low cooling rate. The reasons for this discrepancy were theoretically analyzed. For the size distribution of inclusions, the effect of cooling rate on the number densities of large-sized（〉 2 μm） inclusions and small-sized（≤ 2 μm） inclusions were distinct. The number density of inclusions larger than 1 μm was not affected when the cooing rate was less than or equal to 6 K·s^-1 because inclusion precipitation was suppressed by the increased cooling rate.

关键词： solidification cooling rate inclusions size distribution number density stainless steels

Management of procedural pain in the intensive care unit

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World Journal of Clinical Cases 2022年第5期10卷 1473-1484页

作者： Na-Na guo Hong-liang Wang Ming-Yan Zhao jian-guo li Hai-Tao liu Ting-Xin Zhang Xin-Yu Zhang Yi-Jun Chu Kai-jiang Yu Chang-Song Wang Department of Critical Care Medicine Harbin Medical University Cancer HospitalHarbin 150081Heilongjiang ProvinceChina Department of Critical Care Medicine The Second Affiliated Hospital of Harbin Medical UniversityHarbin 150081Heilongjiang ProvinceChina Department of Critical Care Medicine The First Affiliated Hospital of Harbin Medical UniversityHarbin 150081Heilongjiang ProvinceChina Department of Intensive Care Unit Zhongnan Hospital of Wuhan UniversityWuhan 430000Hubei ProvinceChina Department of Orthopedics The Second Affiliated Hospital of Harbin Medical UniversityHarbin 150081Heilongjiang ProvinceChina

Pain is a common experience for inpatients,and intensive care unit(ICU)patients undergo more pain than other departmental patients,with an incidence of 50%at rest and up to 80%during common care procedures.At present,the management of persistent pain in ICU patients has attracted considerable attention,and there are many related clinical studies and guidelines.However,the management of transient pain caused by certain ICU procedures has not received sufficient attention.We reviewed the different management strategies for procedural pain in the ICU and reached a conclusion.Pain management is a process of continuous quality improvement that requires multidisciplinary team cooperation,painrelated training of all relevant personnel,effective relief of all kinds of pain,and improvement of patients'quality of life.In clinical work,which involves complex and diverse patients,we should pay attention to the following points for procedural pain:(1)Consider not only the patient's persistent pain but also his or her procedural pain;(2)Conduct multimodal pain management;(3)Provide combined sedation on the basis of pain management;and(4)Perform individualized pain management.Until now,the pain management of procedural pain in the ICU has not attracted extensive attention.Therefore,we expect additional studies to solve the existing problems of procedural pain management in the ICU.

关键词： Procedural pain Persistent pain Transient pain Pain management Topical anesthesia Intensive care unit

Intelligent Mining Technology for an Underground Metal Mine Based on Unmanned Equipment

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Engineering 2018年第3期4卷 381-391页

作者： jian-guo li Kai Zhan BGRIMM Technology Group Beijing 100160 China

This article analyzes the current research status and development trend of intelligent technologies for underground metal mines in China, where such technologies are under development for use to develop mineral resources in a safe, efficient, and environmentally friendly manner. We analyze and summarize the research status of underground metal mining technology at home and abroad, including some specific examples of equipment, technology, and applications. We introduce the latest equipment and technologies with independent intellectual property rights for unmanned mining, including intelligent and unmanned control technologies for rock-drilling jumbos, down-the-hole (DTH) drills, underground scrapers, underground mining trucks, and underground charging vehicles. Three basic platforms are used for intelligent and unmanned mining: the positioning and navigation platform, information-acquisition and communication platform, and scheduling and control platform. Unmanned equipment was tested in the Fankou Lead-Zinc Mine in China, and industrial tests on the basic platforms of intelligent and unmanned mining were carried out in the mine. The experiment focused on the intelligent scraper, which can achieve autonomous intelligent driving by relying on a wireless communication system, location and navigation system, and data-acquisition system. These industrial experiments indicate that the technology is feasible. The results show that unmanned mining can promote mining technology in China to an intelligent level and can enhance the core competitive ability of China’s mining industry.

关键词： Underground Autonomous Communication Navigation Intelligent

Donor-Derived Transmission of Scedosporiosis in Kidney Transplant Recipients from a Systemic lupus erythematosus donor

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Current Medical Science 2023年第2期43卷 417-420页

作者： Cheng ZENG Yong-sheng MA Jun-ying ZHOU Cheng-biao XUE Yan XIONG Wei ZHOU li-hua ZHOU jian-guo li Shao-jun YE Qi-fa YE Zhongnan Hospital of Wuhan University Institute of Hepatobiliary Diseases of Wuhan UniversityTransplant Center of Wuhan UniversityNational Quality Control Center for Donated Organ ProcurementHubei Key Laboratory of Medical Technology on TransplantationHubei Clinical Research Center for Natural Polymer Biological LiverHubei Engineering Center of Natural Polymer-based Medical MaterialsWuhan430071China Department of Laboratory Medicine Zhongnan Hospital of Wuhan UniversityWuhan430071China Intensive Care Unit Zhongnan Hospital of Wuhan UniversityWuhan430071China The Third Xiangya Hospital of Central South University Research Center of National Health Ministry on Transplantation Medicine Engineering and TechnologyChangsha410013China

Donor-derived infection(DDI)associated with Scedosporium spp is extremely rare,and results in a very poor prognosis.The present study reports a probable DDI due to Scedosporium boydii(S.boydii)from a donor with neuropsychiatric systemic lupus erythematosus.Two recipients developed Scedosporiosis after kidney transplantation from the same donor.Recipient 1 died of central nervous system infection due to S.boydii based on the clinical presentations,and the positive metagenomic next-generation sequencing(mNGS)and culture results for the cerebrospinal fluid.The other recipient with urinary tract obstruction due to S.boydii,which was identified through the positive culture and mNGS results of the removed stents,was successfully treated by stent replacement and voriconazole administration.Undiagnosed disseminated donor infection and the transmission of S.boydii should be given attention,particularly when the donor and recipients have primary immunodeficiency disease.The screening of donors and recipients for S.boydii using mNGS may be helpful in guiding antifungal prophylaxis and treatment recipients,due to its higher sensitivity and shorter diagnostic time relative to other traditional techniques.

关键词： kidney transplant Scedosporium boydii fungal infection donor-derived infection

Distributions of Sr and Fe and their influence on modification of hypoeutectic Al-Si alloy

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China Foundry 2016年第2期13卷 85-92页

作者： Tu Lan jian-guo li School of Materials Tsinghua University

The influence of cooling rate and Fe-containing phases on Sr-modification of Si phases in hypoeutectic Al-Si alloys, a problem with great industrial importance, was investigated. The microstructures of samples were examined using scanning electron microscopy(SEM) with energy-dispersive X-ray spectroscopy(EDX). A new method of electron probe microanalysis(EPMA) map scanning was used to analyze the Sr distribution, which gave quantitative results covering more Si particles. EPMA map scanning, together with SEM with EDX, was also used in analyzing the distribution of Fe phases. Results show that Fe-containing phase was related to the unmodified Si particles in samples with partial modification failure and the plate-like Si phases in samples without modification failure. Such a relationship was further confirmed by the microstructure observation.In conclusion, a partial failure of Sr-modification can be caused by both slow cooling rate and Fe-containing phases.

关键词： Al-Si Alloys cooling rate modification theory Sr segregation Fe-contained phases

SIRT1 facilitates amyloid beta peptide degradation by upregulating lysosome number in primary astrocytes

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Neural Regeneration Research 2018年第11期13卷 2005-2013页

作者： Min-Zhe li liang-Jun Zheng jian Shen Xin-Ya li Qi Zhang Xue Bai Qing-Song Wang jian-guo li General Surgery Department Beijing Chao-Yang HospitalCapital Medical University Beijing China State Key Laboratory of Protein and Plant Gene Research College of Life Sciences Peking University Beijing China

Previous studies have shown that sirtuin 1（SIRT1） reduces the production of neuronal amyloid beta（Aβ） and inhibits the inflammatory response of glial cells, thereby generating a neuroprotective effect against Aβ neurotoxicity in animal models of Alzheimer＇s disease. However, the protective effect of SIRT1 on astrocytes is still under investigation. This study established a time point model for the clearance of Aβ in primary astrocytes. Results showed that 12 hours of culture was sufficient for endocytosis of oligomeric Aβ, and 36 hours sufficient for effective degradation. Immunofluorescence demonstrated that Aβ degradation in primary astrocytes relies on lysosome function. Enzymatic agonists or SIRT1 inhibitors were used to stimulate cells over a concentration gradient. Aβ was co-cultured for 36 hours in medium. Western blot assay results under different conditions revealed that SIRT1 relies on its deacetylase activity to promote intracellular Aβ degradation. The experiment further screened SIRT1 using quantitative proteomics to investigate downstream, differentially expressed proteins in the Aβ degradation pathway and selected the ones related to enzyme activity of SIRT1. Most of the differentially expressed proteins detected are close to the primary astrocyte lysosomal pathway. Immunofluorescence staining demonstrated that SIRT1 relies on its deacetylase activity to upregulate lysosome number in primary astrocytes. Taken together, these findings confirm that SIRT1 relies on its deacetylase activity to upregulate lysosome number, thereby facilitating oligomeric Aβ degradation in primary astrocytes.

关键词： nerve regeneration amyloid beta peptide Alzheimer＇s disease neurodegeneration astrocytes gliocytes sirtuin 1 quantitative proteomics lysosome time point model peptide degradation neural regeneration

Observation of Bi Coarsening and Dissolution Behaviors in Melting Al–Bi Immiscible Alloy

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Acta Metallurgica Sinica(English Letters) 2016年第9期29卷 800-803页

作者： Wen-Quan Lu Shu-Guang Zhang jian-guo li School of Materials Science and Engineering Shanghai Jiao Tong University School of Environmental Science and Engineering Shanghai Jiao Tong University

Using synchrotron radiography, a melting process of the AI-10 wt% Bi immiscible alloy was fully observed, and Bi solute coarsening and dissolution behaviors as well as their effect on the microstructural evolution were also investi- gated. We found that two different steps including coarsening and dissolution processes can be used to describe the structure evolution in melting AI-10 wt% Bi immiscible alloy. And diffusion coalescence controlled the coalescence of Bi droplets at the early stage of the melting AI-10 wt% Bi immiscible alloy, while the coagulation dttring movement did at later stage. Also, the larger the droplet, the larger the distance of the steady-state concentration distribution around the droplet.

关键词： Immiscible alloy Coarsening Dissolution Synchrotron radiography