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Numerical simulation of melt flow and temperature field during DC casting 2024 aluminium alloy under different casting conditions

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China Foundry 2024年第4期21卷 387-396页

作者： jin-chuan Wang Yu-bo Zuo Qing-feng Zhu jing li Rui Wang Xu-dong liu Key Laboratory of Electromagnetic Processing of Materials Ministry of EducationNortheastern UniversityShenyang 110819China School of Materials Science and Engineering Northeastern UniversityShenyang 110819China Engineering Research Center of Advanced Materials Preparing Technology Ministry of EducationShenyang 110819China CAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

Casting speed,casting temperature and secondary cooling water flow rate are the main process parameters affecting the DC casting *** parameters significantly influence the flow and temperature fields during casting,which are crucial for the quality of the ingot and can determine the success or failure of the casting *** simulation,with the advantages of low cost,rapid execution,and visualized results,is an important method to study and optimize the DC casting *** the present work,a simulation model of DC casting 2024 aluminum alloy was established,and the reliability of the model was ***,the influence of casting parameters on flow field and temperature field was studied in detail by numerical simulation *** show that with the increase of casting speed,the melt flow becomes faster,the depths of slurry zone and mushy zone increase,and the variation of slurry zone depth is greater than that of mushy *** an increase in casting temperature,the melt flow rate increases,the depth of the slurry zone becomes shallower,and the depth of the mushy zone experiences only minor *** simulation results further indicate that the increase of the flow rate of the secondary cooling water slightly reduces the depths of both slurry and mushy zone.

关键词： aluminium DC casting flow field temperature field numerical simulation

A shallow ice core from East Greenland showing a reduction in black carbon during 1990-2016

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Advances in Climate Change Research 2020年第4期11卷 360-369页

作者： DU Zhi-Heng XIAO Cun-De DOU Ting-Feng li chuan-jin DING Ming-Hu Sangeeta SHARMA MA Xiang-Yu WANG Shi-Meng ZHANG Wang-Bing State Key Laboratory of Cryospheric Science Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou730000China Southern Marine Science and Engineering Guangdong Laboratory Guangzhou511458China State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing100875China University of Chinese Academy of Science Beijing100049China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing100081China Climate Research Division Environment and Climate Change CanadaTorontoM3H 5T4Canada School of Geographic and Oceanographic Sciences Nanjing UniversityNanjing210023China

This study reports on the measurements of ion and refractory black carbon(rBC)concentrations in a shallow(10.96 m)ice core sample which was drilled from the field site of the East Greenland Ice Core Project(EGRIP)in July,*** results provide a recent record of rBC deposition in the East Greenland ice sheet from 1990 to *** annual variability in oxygen(δ^(18)O)and hydrogen(δD)isotopic compositions indicated that notably warm events occurred since *** in rBC occurred during summer seasons,which may be attributed to the burning of biomass in boreal *** rBC record and analysis of historical air trajectories using the HYSPliT model indicated that anthropogenic BC emissions from Russia,North America and Europe contributed to the majority of rBC deposition in the Greenland region,and a reduction in anthropogenic BC consumption in these areas played a dominant role in the decrease in BC concentrations since *** record also suggests that the emissions from the East Asian region(China)contributed very little to the recorded BC concentrations in East Greenland ice *** model results indicated that radiative forcing due to BC had decreased significantly since 1990,and had remained below 0.02W m^(-2) since 2000.

关键词： East Greenland Ice core Black carbon Seasonal variability Potential emission sources

Trace formula of the integro-differential operator on a quantum graph

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Applied Mathematics(A Journal of Chinese Universities) 2024年第2期39卷 311-318页

作者： WEI li-xiao YANG chuan-fu School of Mathematics and Statistics Nanjing University of Science and TechnologyNanjing 210094China.

In this paper we study the eigenvalue problem for integro-differential operators on a lasso *** trace formula of the operator is established by applying the residual technique in complex analysis.

关键词： integro-differential operators eigenvalue trace formula

Physiological and pathological functions of circular RNAs in the nervous system

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Neural Regeneration Research 2024年第2期19卷 342-349页

作者： Min Zhou Shi li chuan Huang School of life Sciences Chongqing UniversityChongqingChina

Circular RNAs(circRNAs)are a class of covalently closed single-stranded RNAs that are expressed during the development of specific cells and *** play crucial roles in physiological and pathological processes by sponging microRNAs,modulating gene transcription,controlling the activity of certain RNA-binding proteins,and producing functional peptides.A key focus of research at present is the functionality of circRNAs in the nervous system and several advances have emerged over the last 2 ***,the precise role of circRNAs in the nervous system has yet to be comprehensively *** this review,we first summarize the recently described roles of circRNAs in brain development,maturity,and ***,we focus on the involvement of circRNAs in various diseases of the central nervous system,such as brain cancer,chronic neurodegenerative diseases,acute injuries of the nervous system,and neuropathic pain.A better understanding of the functionality of circRNAs will help us to develop potential diagnostic,prognostic,and therapeutic strategies to treat diseases of the nervous system.

关键词： Alzheimer’s disease amyotrophic lateral sclerosis brain development circRNAs neuropathic pain Parkinson’s disease

Enhanced electrochemical performance of li_(1.3)Al_(0.3)Ti_(1.7)(PO_(4))_(3) solid electrolyte by anion doping

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Nano Research 2024年第3期17卷 1465-1472页

作者： jingrui Kang Xu Guo Rui Gu Honglei Hao Yi Tang Jiahui Wang li jin Hongfei li Xiaoyong Wei Electronic Materials Research Laboratory Key Laboratory of the Ministry of Education&International Center for Dielectric ResearchSchool of Electronic and Information EngineeringXi’an Jiaotong UniversityXi’an 710049China School of Energy and Materials Shanghai Key Laboratory of Engineering Materials Application and EvaluationShanghai Polytechnic UniversityShanghai 201209China

Nowadays,the majority of the studies on the substitution are focused on cations(such as Y^(3+),Ti^(4+),P^(5+),etc.)in li_(1.3)Al_(0.3)Ti_(1.7)(PO_(4))_(3)(LATP),while there are few studies on the substitution of anion O^(2-).In this work,the modified LATP with a series of liCl(LATPClx,x=0.1,0.2,0.3,0.4)additives is prepared to enhance ionic *** successful introduction of Cl-makes the length of the c axis decrease from 20.822(2)to 20.792(1)Å,and the bulk conductivity of 2.13×10^(-3) S·cm^(-1) is achieved in LATPCl_(0.3).Moreover,the Al/Ti-O1/Cl1 and Al/Ti-O_(2)/Cl_(2) distance decrease,while the li1-O_(2)/Cl_(2) distance *** ions migrate more easily in the nanochannel of *** addition,the liCl additive increases the relative density and the grain boundary conductivity of LATPClx ***,a higher ionic conductivity of 2.12×10^(–4) S·cm^(-1) and a low activation energy of 0.30 eV are obtained in LATPCl_(0.3).Correspondingly,the symmetric cell exhibits a low overpotential of±50 mV for over 200 h in LATPCl_(0.3).The solid-state li|LATPCl_(0.3)|NCM811(NCM811=liNi0.8Co0.1Mn0.1O_(2))battery exhibits high initial capacity 185.1 mAh·g^(-1) with a capacity retention rate of 95.4%after 100 cycles at 0.5 *** result suggests that liCl additive is an effective strategy to promote electrochemical properties of LATP solid electrolyte and can be considered for reference to other inorganic solid electrolytes systems.

关键词： li_(1.3)Al_(0.3)Ti_(1.7)(PO_(4))_(3)(LATP)solid electrolyte anion doping ionic conductivity cyclic performance

Carbon felt electrode coated with WS2 enables a high-performance polysulfide/ferricyanide flow battery

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Rare Metals 2024年第10期43卷 5039-5047页

作者： liang-Yu li Su Yan Ying-Jia Huang Fang-Fang Zhong jin-Chao Cao Mei Ding chuan-Kun Jia College of Materials Science and Engineering Changsha University of Science and Technology Institute of Energy Storage Technology College of Energy and Power EngineeringChangsha University of Science and Technology Binzhou Institute of Technology Weiqiao-UCAS Science and Technology Park

Polysulfide/ferricyanide flow batteries （S/Fe RFBs）,with the advantages of abundant earth reservation low cost,high safety,and environmental friendliness,have attracted significant interest and demonstrated noteworthy potential for practical ***,the battery performance,including the energy efficiency （EE）,voltage efficiency （VE）,and power density of the S/Fe RFBs remains low owing to the slow redox kinetics of polysulfide *** address these concerns,WS2was selected as the booster and deposited on a commercial carbon felt electrode （WS2–CF） to stimulate the redox reactions of polysulfide *** better hydrophilicity and smaller charge-transfer resistance,WS2–CF exhibits enhanced electrochemical activity toward polysulfide redox ***,the battery performance of S/Fe RFB with WS2–CF as the anode has been improved,with EE of 84%,VE of 84%,and a peak power density of 175.7 mW·cm-2,which are all higher than the cell only with the bare carbon felt （CF） as electrodes (76%,77% and 155.8 mW·cm-2,respectively).Furthermore,the cycling life of the S/Fe RFB with WS2–CF has been prolonged to 2200 cycles with a capacity retention of 96% a 40 mA·cm-2because of the good stability of WS2–CF as the ***,under the same conditions,the S/Fe RFB without WS2–CF terminated after 1500 cycles with a fast capacity *** successful utilization of WS2as a booster on an electrode provides an efficient strategy for obtaining advanced S/Fe RFBs for practical applications.

关键词： Carbon felt Energy storage Polysulfide/ferricyanide flow battery Tungsten disulfide

Advanced Algorithm for Parameters Estimation of Negative Binomial Distribution with High Dimensional Sparse Group Structure

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Journal of Systems Science & Complexity 2024年第5期37卷 2173-2195页

作者： li Meiqi jin Baisuo School of Management University of Science and Technology of ChinaHefei 230000China

Negative binomial regression is a powerful technique for modeling count data,particularly when dealing with ***,estimating the parameters for large-dimensional sparse models is challenging due to the complexity of optimizing the mean and dispersion parameter of the negative binomial *** address this issue,the authors propose a novel approach that employs two iterations of the majorize-minimize(MM)algorithm,one for estimating the dispersion parameter and the other for estimating the mean *** approaches improve the convergence speed and stability of the *** authors also use group penalty for variable selection,which enhances the accuracy and efficiency of the *** proposed method provides an explicit solution,simplifies the iteration process,and maintains good stability while ensuring algorithm ***,the authors apply the proposed algorithm to the zero-inflated model and demonstrate its promising predictive performance on specific data *** research has important implications for count data modeling and analysis in various fields,such as data mining,machine learning,and bioinformatics.

关键词： Group structure majorize-minimize(MM) negative binomial

Preoperative prediction of perineural invasion of rectal cancer based on a magnetic resonance imaging radiomics model:A dual-center study

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World Journal of Gastroenterology 2024年第16期30卷 2233-2248页

作者： Yan liu Bai-jin-Tao Sun chuan Zhang Bing li Xiao-Xuan Yu Yong Du Department of Radiology The Affiliated Hospital of North Sichuan Medical CollegeNanchong 637000Sichuan ProvinceChina Department of Radiology The Affiliated Hospital of North Sichuan Medical CollegeNanchong 637000Sichuan ProvinceChina.duyong@***

BACKGROUND Perineural invasion(PNI)has been used as an important pathological indicator and independent prognostic factor for patients with rectal cancer(RC).Preoperative prediction of PNI status is helpful for individualized treatment of ***,several radiomics studies have been used to predict the PNI status in RC,demonstrating a good predictive effect,but the results lacked *** preoperative prediction of PNI status is still challenging and needs further *** To establish and validate an optimal radiomics model for predicting PNI status preoperatively in RC *** This retrospective study enrolled 244 postoperative patients with pathologically confirmed RC from two independent *** patients underwent preoperative high-resolution magnetic resonance imaging(MRI)between May 2019 and August *** radiomics features were extracted and selected from oblique axial T2-weighted imaging(T2WI)and contrast-enhanced T1WI(T1CE)*** radiomics signatures were constructed using logistic regression analysis and the predictive potential of various sequences was compared(T2WI,T1CE and T2WI+T1CE fusion sequences).A clinical-radiomics(CR)model was established by combining the radiomics features and clinical risk *** internal and external validation groups were used to validate the proposed *** area under the receiver operating characteristic curve(AUC),DeLong test,net reclassification improvement(NRI),integrated discrimination improvement(IDI),calibration curve,and decision curve analysis(DCA)were used to evaluate the model *** Among the radiomics models,the T2WI+T1CE fusion sequences model showed the best predictive performance,in the training and internal validation groups,the AUCs of the fusion sequence model were 0.839[95%confidence interval(CI):0.757-0.921]and 0.787(95%CI:0.650-0.923),which were higher than those of the T2WI and T1CE sequence *** CR model constructed by combinin

关键词： Rectal cancer Perineural invasion Magnetic resonance imaging Radiomics Nomogram

Alkyl Radical Initiated Cyclization/Cascade for Synthesizing Lactam-Substituted Alkyl Sulfones

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Chinese Journal of Chemistry 2024年第16期42卷 1853-1859页

作者： li-Jun Wu Kai-Yi Zhang Pei Yang chuan-Chong Peng jin-Hui liu Qing li Da-Zhi Sun Shuangfeng Yin College of Sciences Central South University of Forestry and TechnologyChangshaHunan410004 China School of Chemistry and Chemical Engineering Inner Mongolia UniversityHohhotInner Mongolia010021 China

An alkyl radical initiated cyclization/tandem reaction of alkyl bromides and alkyl electrophiles by using potassium metabisulphite(K_(2)S_(2)O_(5))as a connector is developed for the synthesis of various lactam-substituted alkyl ***,this process does not require a metal catalyst or metal powder reductant,highlighting its environmentally friendly *** reaction demonstrates outstanding substrate adaptability and a high tolerance towards diverse functional ***,the biologically active molecules and commercially available drugs with a late-stage modification are also highly compatible with this *** studies revealed that the reaction proceeds through a single-step process involving intramolecular radical cyclization,"SO_(2)"insertion,and external alkyl incorporation.

关键词： Alkyl radical Metal-free catalyzed Cyclization/cascade Potassium metabisulphite Electrophiles Alkyl sulfones Lactams Alkyl bromides Sodium formate