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Permanent lining castable with low bulk density and thermal conductivity:bauxite castable for tundish obtained by adding pearlescent sand

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Journal of Iron and Steel Research(International) 2024年第3期31卷 634-646页

作者： Yi Wang jian Yang Bao Wang Hai-jun Zhang Juan Han pei-yan pei Wen-long Lv jian-an Zhou 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 Wuhan Research Institute of Metallurgical Construction MCCWuhan 430081HubeiChina

The low thermal conductivity and light mass of castables for tundish permanent linings are crucial for minimizing the heat loss of molten steel.In consideration of the low bulk density and thermal conductivity of pearlescent sand,the thermal insulation performance of castables was attempted to be improved by adding pearlescent sand.Pearlescent sand was modified to prevent the strength of its porous structure from deteriorating.The modification mechanism of pearlescent sand and the effect of pearlescent sand on the performance of bauxite castables were studied.The results suggested that the addition of the modified pearlescent sand significantly raised the apparent porosity and decreased the bulk density of bauxite castable.At 1000℃,the bulk density of more than 60%of the modified pearlescent sand-bauxite castable was only 2.03 g/cm^(3).The mechanical properties and thermal shock resistance of the modified pearlescent sand-bauxite castable were inferior to those of conventional bauxite castable but were adequate to meet the use conditions of casta-bles for tundish permanent linings.At high temperatures of 200-800℃,the thermal conductivity of more than 60%of the modified pearlescent sand-bauxite castable was smaller than that of conventional bauxite castable.The addition of the modified pearlescent sand can greatly reduce the thermal conductivity and bulk density of bauxite castable.

关键词： Pearlescent sand-Hydrophobic modification Bauxite castable Thermal insulation performance Mechanical property

An Outbreak of Serogroup Y Meningococcal Meningitis in a Private Secondary Vocational School-Guangzhou City,Guangdong Province,China,2023

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China CDC weekly 2024年第12期6卷 242-246,I0005页

作者： Xiang Zeng Qing He Yilan Li Yong Zhou Xiaoping Shao pei Hu jian Liang Yudan Song Chao Ma Lijie Zhang Limei sun Lei Luo Chinese Field Epidemiology Training Program Chinese Center for Disease Control and PreventionBeijingChina Zhuhai Center for Disease Control and Prevention Zhuhai CityGuangdong ProvinceChina Guangdong Center for Disease Control and Prevention Guangzhou CityGuangdong ProvinceChina Guangzhou Center for Disease Control and Prevention Guangzhou CityGuangdong ProvinceChina Institute of Public Health Guangzhou Medical University&Guangzhou Center for Disease Control and PreventionGuangzhou CityGuangdong ProvinceChina Department of the National Immunization Programme Chinese Center for Disease Control and PreventionBeijingChina

What is already known about this topic?The inclusion of meningococcal vaccines in the National Immunization Program(NIP)over several years has significantly reduced the incidence of meningococcal meningitis in China to historic lows.Worldwide,there has been a diversification of meningococcal serogroups,leading to a shift in dominant serogroups in China from serogroup A to serogroups C and B,accompanied by a rise in reports of serogroups Y and W.What is added by this report?An outbreak of serogroup Y Neisseria meningitidis(Nm)in a secondary vocational school involved a single confirmed severe case and 24 individuals with laboratory-confirmed Nm carriage.Epidemiological investigation revealed that the outbreak was localized to the classroom of the confirmed case.Prolonged close contact within a confined space was identified as a significant risk factor for Nm transmission.The genotype sequence identified was type 1655(ST-1655),which is categorized under clonal complex 23(CC-23)and bears resemblance to 8 previously confirmed cases of serogroup Y meningococcal meningitis within Guangdong Province.This suggests that serogroup Y infections continue to sporadically emerge and have become prevalent strains.What are the implications for public health practice?This outbreak underscores the critical need to enhance surveillance of meningococcal serogroups and population carrier,and advocate for vaccination with MenY-containing vaccines.

关键词： break Secondary Guangdong

Exploring changes of precipitation extremes under climate change through global variable-resolution modeling

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Science Bulletin 2024年第2期69卷 237-247页

作者： Wei sun jian Li Rucong Yu Nina Li Yi Zhang State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China Institute of Tibetan Plateau Meteorology China Meteorological AdministrationChengdu 610072China Department of Atmospheric Science Yunnan UniversityKunming 650091China National Meteorological Center China Meteorological AdministrationBeijing 100081China 2035 Future Laboratory PIESAT Information Technology Co.Ltd.Beijing 100105China

Understanding the responses of precipitation extremes to global climate change remains limited owing to their poor representations in models and complicated interactions with multi-scale systems.Here we take the record-breaking precipitation over China in 2021 as an example,and study its changes under three different climate scenarios through a developed pseudo-global-warming(PGW)experimental framework with 60-3 km variable-resolution global ensemble modeling.Compared to the present climate,the precipitation extreme under a warmer(cooler)climate increased(decreased)in intensity,coverage,and total amount at a range of 24.3%-37.8%(18.7%-56.1%).With the help of the proposed PGW experimental framework,we further reveal the impacts of the multi-scale system interactions in climate change on the precipitation extreme.Under the warmer climate,large-scale water vapor transport converged from double typhoons and the subtropical high marched into central China,enhancing the convective energy and instability on the leading edge of the transport belt.As a result,the mesoscale convective system(Mcs)that directly contributed to the precipitation extreme became stronger than that in the present climate.On the contrary,the cooler climate displayed opposite changing characteristics relative to the warmer climate,ranging from the large-scale systems to local environments and to the Mcs.In summary,our study provides a promising approach to scientifically assess the response of precipitation extremes to climate change,making it feasible to perform ensemble simulations while investigating the multi-scale system interactions over the globe.

关键词： Precipitation extreme Climate change Pseudo-global-warming experiment Variable-resolution modeling Multi-scale system interaction

Spatial-Temporal Analysis of Drinking Water Type of Endemic Fluorosis—China,2009–2022

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China CDC weekly 2024年第2期6卷 25-29页

作者： Lijun Zhao Zhe Li Mang Li Hongna sun Wei Wei Lin Gao Qiaoshi Zhao Yang Liu Xiaohong Ji Cheng Li jian Wang Yanhui Gao Junrui pei Center for Endemic Disease Control Chinese Center for Disease Control and PreventionHarbin Medical UniversityHarbin CityHeilongjiang ProvinceChina Key Lab of Etiology and Epidemiology Education Bureau of Heilongjiang Province(23618504)Ministry of Health of PRHarbin Medical UniversityHarbin CityHeilongjiang ProvinceChina

What is already known about this topic?Endemic fluorosis,caused by high fluoride levels in drinking water,has been a significant health issue in rural areas of China for many decades.What is added by this report?There has been a notable decline in the detection rate of dental fluorosis in children aged 8–12 years in drinking water fluorosis areas across the country from 2009 to 2022.While 14 provincial-level administrative divisions are classified as low-probability clusters,Tianjin remains classified as a high-probability cluster.What are the implications for public health practice?The current policy for preventing and controlling endemic fluorosis in China needs adjustment.Rather than focusing solely on regions with high incidence,there should be a shift towards monitoring and early warning of fluoride exposure.Additionally,local containment measures should be intensified.

关键词： intensified Spatial fluoride

Disparity estimation for multi-scale multi-sensor fusion

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Journal of Systems Engineering and Electronics 2024年第2期35卷 259-274页

作者： sun Guoliang pei Shanshan LONG Qian ZHENG Sifa YANG Rui Suzhou Automotive Research Institute Tsinghua UniversitySuzhou 215000China Beijing Smarter Eye Technology Co. Ltd.Beijing 100023China College of Artifical Intelligence Tianjin University of Science and TechnologyTianjin 300457China State Key Laboratory of Automotive Safety and Energy Tsinghua UniversityBeijing 100084China Department of Precision Instrument Tsinghua UniversityBeijing 100084China

The perception module of advanced driver assistance systems plays a vital role.Perception schemes often use a single sensor for data processing and environmental perception or adopt the information processing results of various sensors for the fusion of the detection layer.This paper proposes a multi-scale and multi-sensor data fusion strategy in the front end of perception and accomplishes a multi-sensor function disparity map generation scheme.A binocular stereo vision sensor composed of two cameras and a light deterction and ranging(LiDAR)sensor is used to jointly perceive the environment,and a multi-scale fusion scheme is employed to improve the accuracy of the disparity map.This solution not only has the advantages of dense perception of binocular stereo vision sensors but also considers the perception accuracy of LiDAR sensors.Experiments demonstrate that the multi-scale multi-sensor scheme proposed in this paper significantly improves disparity map estimation.

关键词： stereo vision light deterction and ranging(LiDAR) multi-sensor fusion multi-scale fusion disparity map

Substrate screening for superclean graphene growth using firstprinciples calculations

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Nano Research 2024年第4期17卷 2216-2222页

作者： Zhihao Li Xiucai sun Xiaoli sun Wan-jian Yin Zhongfan Liu College of Energy Soochow Institute for Energy and Materials InnovationS(SIEMIS)and Jiangsu Provincial Key Laboratory for Advanced Carbon Materials and Wearable Energy TechnologiesSoochow UniversitySuzhou 215006China Graphene Basic Science Research Center Beijing Graphene Institute(BGI)Beijing 100095China Center for Nanochemistry Beijing Science and Engineering Center for NanocarbonsBeijing National Laboratory for Molecular ScienceCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

Suppressing the formation of amorphous surface carbon and contaminants during the preparation of graphene by chemical vapor deposition remains an ongoing issue.Herein,we analyzed how substrate characteristics affect graphene quality by simulating margin extension,the nucleation process,and defect pegging configurations on mono-crystalline oriented metal substrates with the aim of enhancing graphene cleanliness.Defect formation energy and nucleation potential,which are indirect substrate–graphene interaction features,were found to appropriately evaluate graphene quality.The crystallographic orientation of the metal substrate was discovered to be critical for producing superclean graphene.A low graphene defect density and high nucleation rate on the Cu(100)facet guarantee growth of high-quality graphene,especially in terms of suppressing the formation of amorphous carbon.In addition,rapid kink growth and self-healing on the Cu(100)facet facilitate rapid graphene synthesis,which is also promoted by rapid kink splicing and margin self-repair on this facet.This study provides theoretical insight useful for the synthesis of superclean graphene.

关键词： superclean graphene defects nucleation metal substrates density functional theory calculations

Prediction of lime utilization ratio of dephosphorization in BOF steelmaking based on online sequential extreme learning machine with forgetting mechanism

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International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 508-517页

作者： Runhao Zhang jian Yang Han sun Wenkui Yang State Key Laboratory of Advanced Special Steel School of Materials Science and EngineeringShanghai UniversityShanghai 200444China

The machine learning models of multiple linear regression(MLR),support vector regression(SVR),and extreme learning ma-chine(ELM)and the proposed ELM models of online sequential ELM(OS-ELM)and OS-ELM with forgetting mechanism(FOS-ELM)are applied in the prediction of the lime utilization ratio of dephosphorization in the basic oxygen furnace steelmaking process.The ELM model exhibites the best performance compared with the models of MLR and SVR.OS-ELM and FOS-ELM are applied for sequential learning and model updating.The optimal number of samples in validity term of the FOS-ELM model is determined to be 1500,with the smallest population mean absolute relative error(MARE)value of 0.058226 for the population.The variable importance analysis reveals lime weight,initial P content,and hot metal weight as the most important variables for the lime utilization ratio.The lime utilization ratio increases with the decrease in lime weight and the increases in the initial P content and hot metal weight.A prediction system based on FOS-ELM is applied in actual industrial production for one month.The hit ratios of the predicted lime utilization ratio in the error ranges of±1%,±3%,and±5%are 61.16%,90.63%,and 94.11%,respectively.The coefficient of determination,MARE,and root mean square error are 0.8670,0.06823,and 1.4265,respectively.The system exhibits desirable performance for applications in actual industrial pro-duction.

关键词： basic oxygen furnace steelmaking machine learning lime utilization ratio dephosphorization online sequential extreme learning machine forgetting mechanism

Sustained release of vascular endothelial growth factor A and basic fibroblast growth factor from nanofiber membranes reduces oxygen/glucose deprivation-induced injury to neurovascular units

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Neural Regeneration Research 2024年第4期19卷 887-894页

作者： Yifang Wu Jun sun Qi Lin Dapeng Wang jian Hai Department of Neurosurgery Tongji HospitalSchool of MedicineTongji University Department of Pharmacy Institute of Medical SciencesShanghai Jiao Tong University School of Medicine

Upregulation of vascular endothelial growth factor A/basic fibroblast growth factor(VEGFA/b FGF)expression in the penumbra of cerebral ischemia can increase vascular volume,reduce lesion volume,and enhance neural cell proliferation and differentiation,thereby exerting neuroprotective effects.However,the beneficial effects of endogenous VEGFA/b FGF are limited as their expression is only transiently increased.In this study,we generated multilayered nanofiber membranes loaded with VEGFA/b FGF using layer-by-layer self-assembly and electrospinning techniques.We found that a membrane containing 10 layers had an ideal ultrastructure and could efficiently and stably release growth factors for more than 1 month.This 10-layered nanofiber membrane promoted brain microvascular endothelial cell tube formation and proliferation,inhibited neuronal apoptosis,upregulated the expression of tight junction proteins,and improved the viability of various cellular components of neurovascular units under conditions of oxygen/glucose deprivation.Furthermore,this nanofiber membrane decreased the expression of Janus kinase-2/signal transducer and activator of transcription-3(JAK2/STAT3),Bax/Bcl-2,and cleaved caspase-3.Therefore,this nanofiber membrane exhibits a neuroprotective effect on oxygen/glucose-deprived neurovascular units by inhibiting the JAK2/STAT3 pathway.

关键词： brain ischemia brain microvascular endothelial cell nanofiber membrane neurovascular unit

A Method for Detecting and Recognizing Yi Character Based on Deep Learning

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Computers, Materials & Continua 2024年第2期78卷 2721-2739页

作者： Haipeng sun Xueyan Ding jian sun HuaYu jianxin Zhang School of Computer Science and Engineering Dalian Minzu UniversityDalian116600China Institute of Machine Intelligence and Bio-Computing Dalian Minzu UniversityDalian116600China 3Yi Language Research RoomChina Ethnic Languages Translation Centre Beijing100080China

Aiming at the challenges associated with the absence of a labeled dataset for Yi characters and the complexity of Yi character detection and recognition,we present a deep learning-based approach for Yi character detection and recognition.In the detection stage,an improved Differentiable Binarization Network(DBNet)framework is introduced to detect Yi characters,in which the Omni-dimensional Dynamic Convolution(ODConv)is combined with the ResNet-18 feature extraction module to obtain multi-dimensional complementary features,thereby improving the accuracy of Yi character detection.Then,the feature pyramid network fusion module is used to further extract Yi character image features,improving target recognition at different scales.Further,the previously generated feature map is passed through a head network to produce two maps:a probability map and an adaptive threshold map of the same size as the original map.These maps are then subjected to a differentiable binarization process,resulting in an approximate binarization map.This map helps to identify the boundaries of the text boxes.Finally,the text detection box is generated after the post-processing stage.In the recognition stage,an improved lightweight MobileNetV3 framework is used to recognize the detect character regions,where the original Squeeze-and-Excitation(SE)block is replaced by the efficient Shuffle Attention(SA)that integrates spatial and channel attention,improving the accuracy of Yi characters recognition.Meanwhile,the use of depth separable convolution and reversible residual structure can reduce the number of parameters and computation of the model,so that the model can better understand the contextual information and improve the accuracy of text recognition.The experimental results illustrate that the proposed method achieves good results in detecting and recognizing Yi characters,with detection and recognition accuracy rates of 97.5%and 96.8%,respectively.And also,we have compared the detection and recognition algorithms proposed in this paper with

关键词： Yi characters text detection text recognition attention mechanism deep neural network