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Study on tungsten sintering temperature field based on electromagnetic simulation and computational fluid dynamics

Tungsten 2024年第2期6卷 355-366页

作者： Lu-Yan Wang Yue-Guang Yu jian-Xin Dong Kai-ping Du Shan-Yu Liu Cao-Bing Li University of Science and Technology Beijing Beijing 100083China BGRIMM Technology Group Beijing 100160China China Iron&Steel Research Institute Group Beijing 100081China

In order to study the influence of various sintering variables more intuitively and clearly,electromagnetic field analysis and computational fl uid dynamics are used to analyze the infl uence of gas flow,heating power and other process parameters on the temperature range of medium-frequency sintering in this *** results indicate that the uniformity of temperature fi eld is determined by the gas flow rate and heating *** the heating power is 50 kW,the stable temperature drops about 10 K for every 1 m^(3)·h^(−1)increase of hydrogen *** peak value of the maximum temperature diff erence on the tungsten rods gradually increases with the increase of the hydrogen flow rate,and it appears slightly *** temperature distribution of tungsten rods in furnace is similar with diff erent hydrogen flow *** the same time,the closer to the furnace wall,the higher the temperature of the tungsten *** temperature diff erence between tungsten rods mainly occurred within 1 h after the beginning of *** the heating power can improve the stable temperature,but has little eff ect on the heating *** heating power can increase the peak value of the maximum temperature diff erence on the tungsten rods,but has little eff ect on the occurrence time of the peak value of the maximum temperature diff erence on the tungsten *** the heating power will increase the temperature diff erence of a single tungsten rod,but the temperature diff erence of a single tungsten rod never exceeds 65 *** study can be used to guide the process optimization *** with numerical simulation calculation,the sintering parameters with low energy consumption and high temperature uniformity can be quickly and eff ectively found,thus improving the microstructure and properties of sintered tungsten products.

关键词： Tungsten products Sintering Hydrogen flow rate Heating power

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An unprotected vulnerable relict subtropical conifer-Keteleeria evelyniana: Its forests, populations, growth and endangerment by invasive alien plant species in China

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Plant Diversity 2024年第5期46卷 648-660页

作者： Cindy Q.Tang Min-Rui Du Huan-Chong Wang you-Cai Shi Jia-Le Zeng Shu-Li Xiao Peng-Bin Han jian-Ran Wen Shi-Qian Yao Ming-Chun Peng Chong-Yun Wang Yong-ping Li Jordi López-Pujol Institute of Ecology and Geobotany College of Ecology and Environmental ScienceYunnan UniversityBuilding#3Guozhong DalouDongwaihuan South RoadUniversity TownChenggong New DistrictKunming 650504YunnanChina College of Life Sciences Yunnan UniversityShengming Kexueyuan Building#2Chenggong CampusDongwaihuan South RoadUniversity TownChenggong New DistrictKunming 650504YunnanChina College of Natural Resources Yunnan UniversityChenggong CampusDongwaihuan South RoadUniversity TownChenggong New DistrictKunming 650504YunnanChina Botanic Institute of Barcelona(IBB CSIC-CMCNC)Passeig del Migdia s/nBarcelona 08038CataloniaSpain Escuela de Ciencias Ambientales Universidad Espíritu Santo(UEES)Samborondon 091650Ecuador

Relict subtropical coniferous forests in China face severe fragmentation,resulting in declining populations,and some are under significant threat from invasive alien *** the crucial importance of understanding forest dynamics,knowledge gaps persist,particularly regarding the impact of invasive plants on vulnerable natives like Keteleeria *** this study,we investigated the impact of invasive plants on the regeneration of forests dominated by ***,a subtropical relict species in southwestern *** this purpose,we characterized forest dynamics of 160 forest plots featuring *** as the primary dominant species and determined whether the presence of invasive plants was correlated with regeneration of *** identified four distinct forest types in which *** was *** found that radial growth of *** trees is faster in younger ageclasses today than it was for older trees at the same *** population structure of *** in each forest type exhibited a multimodal age-class ***,three forest types lacked established saplings younger than 10 years old,a situation attributed to the dense coverage of the invasive alien Ageratina *** invasive species resulted in a reduction of understory species ***,our analysis uncovered a significant negative correlation in phylogenetic relatedness(net relatedness index)between native and invasive alien plant species in eastern *** suggests closely related invasive species face heightened competition,hindering successful *** together,our findings indicate that successful establishment and habitat restoration of *** seedling/saplings require effective measures to control invasive plants.

关键词： Keteleeria evelyniana Age structure Regeneration Species diversity Invasive alien species Phylogenetic relatedness

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Electronic engineering of Co-Ru diatomic sites and Ru nanoparticles for synergistic promotion of hydrogen evolution

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Nano Research 2024年第5期17卷 3714-3723页

作者： Wei Zhang Cong Li Yongyong Cao Jun-Yang Ji Zhao-Chen Li Zheng Niu Hongwei Gu Pierre Braunstein jian-ping Lang College of Chemistry Chemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China College of Biological Chemical Science and EngineeringJiaxing UniversityJiaxing 314001China Universitéde Strasbourg-CNRS Institut de Chimie(UMR 7177 CNRS)4 rue Blaise Pascal-CS 9003267081 StrasbourgFrance

The coexistence of multi-component active sites like single-atom sites,diatomic sites(DAS)and nanoclusters is shown to result in superior performances in the hydrogen evolution reaction(HER).Metal diatomic sites are more complex than single-atom sites but their unique electronic structures can lead to significant enhancement of the HER *** the synthesis and identification of DAS is usually challenging,we report a simple access to a diatomic catalyst by anchoring Co-Ru DAS on nitrogen-doped carbon supports along with Ru nanoparticles(NPs).Experimental and theoretical results revealed the atomic-level characteristics of Co-Ru sites,their strong electronic coupling and their synergy with Ru NPs within the *** unique electronic structure of the catalyst resulted in an excellent HER activity and stability in alkaline *** work provides a valuable insight into a widely applicable design of diatomic catalysts with multi-component active sites for highly efficient HER electrocatalysis.

关键词： Co-Ru diatomic sites Ru nanoparticles multiple active sites synergistic effect hydrogen evolution reaction

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Two-grid Method of Expanded Mixed Finite Element Approximations for Parabolic Integro-differential Optimal Control Problems

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Acta Mathematicae Applicatae Sinica 2024年

作者： Yan-ping CHEN jian-wei ZHOU Tian-liang HOU School of Science Nanjing University of Posts and Telecommunications School of Mathematics and Statistics Linyi University School of Mathematics and Statistics Beihua University

This paper aims to construct a two-grid scheme of fully discretized expanded mixed finite element methods for optimal control problems governed by parabolic integro-differential equations and discuss a priori error estimates. The state variables and co-state variables are discretized by the lowest order Raviart-Thomas mixed finite element, and the control variable is approximated by piecewise constant functions. The time derivative is discretized by the backward Euler method. Firstly, we define some new mixed elliptic projections and prove the corresponding error estimates which play an important role in subsequent convergence ***, we derive a priori error estimates for all variables. Thirdly, we present a two-grid scheme and analyze its convergence. In the two-grid scheme, the solution of the parabolic optimal control problem on a fine grid is reduced to the solution of the parabolic optimal control problem on a much coarser grid and the solution of a decoupled linear algebraic system on the fine grid and the resulting solution still maintains an asymptotically optimal accuracy. At last, a numerical example is presented to verify the theoretical results.

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Multi-surrogate framework with an adaptive selection mechanism for production optimization

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Petroleum Science 2024年第1期21卷 366-383页

作者： Jia-Lin Wang Li-Ming Zhang Kai Zhang jian Wang jian-ping Zhou Wen-Feng Peng Fa-Liang Yin Chao Zhong Xia Yan Pi-Yang Liu Hua-Qing Zhang Yong-Fei Yang Hai Sun School of Petroleum Engineering China University of Petroleum(East China)Qingdao266580ShandongChina Qingdao University of Technology Qingdao266580ShandongChina College of Science China University of PetroleumQingdao266580ShandongChina Zepu Oil and Gas Development Department PetroChina Tarim Oilfield CompanyKorla841000XinjiangChina Hainan Branch of CNOOC Ltd Haikou70311HainanChina

Data-driven surrogate models that assist with efficient evolutionary algorithms to find the optimal development scheme have been widely used to solve reservoir production optimization ***,existing research suggests that the effectiveness of a surrogate model can vary depending on the complexity of the design problem.A surrogate model that has demonstrated success in one scenario may not perform as well in *** the absence of prior knowledge,finding a promising surrogate model that performs well for an unknown reservoir is ***,the optimization process often relies on a single evolutionary algorithm,which can yield varying results across different *** address these limitations,this paper introduces a novel approach called the multi-surrogate framework with an adaptive selection mechanism(MSFASM)to tackle production optimization *** consists of two *** the first stage,a reduced-dimensional broad learning system(BLS)is used to adaptively select the evolutionary algorithm with the best performance during the current optimization *** the second stage,the multi-objective algorithm,non-dominated sorting genetic algorithm II(NSGA-II),is used as an optimizer to find a set of Pareto solutions with good performance on multiple surrogate models.A novel optimal point criterion is utilized in this stage to select the Pareto solutions,thereby obtaining the desired development schemes without increasing the computational load of the numerical *** two stages are combined using sequential transfer *** the two most important perspectives of an evolutionary algorithm and a surrogate model,the proposed method improves adaptability to optimization problems of various reservoir *** verify the effectiveness of the proposed method,four 100-dimensional benchmark functions and two reservoir models are tested,and the results are compared with those obtained by six other surrogate-model-based *** res

关键词： Production optimization Multi-surrogate models Multi-evolutionary algorithms Dimension reduction Broad learning system

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Pre-operative enhanced magnetic resonance imaging combined with clinical features predict early recurrence of hepatocellular carcinoma after radical resection

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World Journal of Gastrointestinal Oncology 2024年第4期16卷 1192-1203页

作者： jian-ping Chen Ri-Hui Yang Tian-Hui Zhang Li-An Liao Yu-Ting Guan Hai-Yang Dai Department of Intervention Meizhou People’s HospitalMeizhou 514031Guangdong ProvinceChina Department of Medical Imaging Meizhou People’s HospitalMeizhou 514031Guangdong ProvinceChina Department of Medical Imaging Huizhou Municipal Central HospitalHuizhou 516001Guangdong ProvinceChina

BACKGROUND Indentifying predictive factors for postoperative recurrence of hepatocellular carcinoma(HCC)has great significance for patient *** To explore the value of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid(Gd-EOB-DTPA)enhanced magnetic resonance imaging(MRI)combined with clinical features in predicting early recurrence of HCC after *** A total of 161 patients with pathologically confirmed HCC were *** patients were divided into early recurrence and non-early recurrence group based on the follow-up *** clinical,laboratory,pathological results and Gd-EOB-DTPA enhanced MRI imaging features were *** Of 161 patients,73 had early recurrence and 88 were had non-early *** analysis showed that patient age,gender,serum alpha-fetoprotein level,the Barcelona Clinic Liver Cancer stage,China liver cancer(CNLC)stage,microvascular invasion(MVI),pathological satellite focus,tumor size,tumor number,tumor boundary,tumor capsule,intratumoral necrosis,portal vein tumor thrombus,large vessel invasion,nonperipheral washout,peritumoral enhancement,hepatobiliary phase(HBP)/tumor signal intensity(SI)/peritumoral SI,HBP peritumoral low signal and peritumoral delay enhancement were significantly associated with early recurrence of HCC after *** logistic regression analysis showed that patient age,MVI,CNLC stage,tumor boundary and large vessel invasion were independent predictive *** data validation indicated that the area under the curve of the combined predictors was 0.861,suggesting that multivariate logistic regression was a reasonable predictive model for early recurrence of *** Gd-EOB-DTPA enhanced MRI combined with clinical features would help predicting the early recurrence of HCC after operation.

关键词： Hepatocellular carcinoma Enhanced magnetic resonance imaging Microvascular invasion Hepatobiliary phase Recurrence

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Effect of quenching cooling rate on residual stress and microstructure evolution of 6061 aluminum alloy

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Journal of Central South University 2024年第7期31卷 2167-2180页

作者： HUANG Ke YI you-ping HUANG Shi-quan HE Hai-lin LIU Jie HUA Hong-en TANG Yun-jian Research Institute of Light Alloy Central South UniversityChangsha 410083China State Key Laboratory of Precision Manufacturing for Extreme Service Performance Changsha 410083China School of Mechanical and Electrical Engineering Central South UniversityChangsha 410083China

In this study,the cooling rate was manipulated by quenching with water of different temperatures(30,60 and 100℃).Surface and internal residual stresses in the quenched 6061 aluminum alloy samples were measured using hole-drilling and crack compliance methods,***,the processability of the quenched samples was evaluated at cryogenic *** mechanical properties of the as-aged samples were assessed,and microstructure evolution was *** surface residual stresses of samples W30℃,W60℃and W100℃is−178.7,−161.7 and−117.2 MPa,respectively along x-direction,respectively;and−191.2,−172.1 and−126.2 MPa,respectively along *** sample quenched in boiling water displaying the lowest residual stress(~34%and~60%reduction in the surface and core).The generation and distribution of quenching residual stress could be attributed to the lattice distortion *** plasticity was also exhibited in the samples with relatively low quenching cooling rates at cryogenic *** strengthes of the as-aged samples are 291.2 to 270.1 MPa as the quenching water temperature increase from 30℃to 100℃.Fine and homogeneous β"phases were observed in the as-aged sample quenched with boiling water due to the clusters and Guinier-Preston zones(GP zones)premature precipitated during quenching process.

关键词： 6061 aluminum alloy residual stress cooling rate cryogenic cooling mechanical properties microstructure evolution

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Short-term displacement prediction for newly established monitoring slopes based on transfer learning

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China Geology 2024年第2期7卷 351-364页

作者： Yuan Tian Yang-landuo Deng Ming-zhi Zhang Xiao Pang Rui-ping Ma jian-xue Zhang Institute of Remote Sensing and Geographical Information Systems Peking UniversityBeijing 100871China Beijing Key Laboratory of Spatial Information Integration and Its Applications Beijing 100871China Institute of Public Safety Research Department of Engineering PhysicsTsinghua UniversityBeijing 100084China China Institute of Geo-Environment Monitoring Beijing 100081China Technology Innovation Center for Geohazard Monitoring and Risk Early Warning Ministry of Natural ResourcesBeijing 100081China

This study makes a significant progress in addressing the challenges of short-term slope displacement prediction in the Universal Landslide Monitoring Program,an unprecedented disaster mitigation program in China,where lots of newly established monitoring slopes lack sufficient historical deformation data,making it difficult to extract deformation patterns and provide effective predictions which plays a crucial role in the early warning and forecasting of landslide hazards.A slope displacement prediction method based on transfer learning is therefore ***,the method transfers the deformation patterns learned from slopes with relatively rich deformation data by a pre-trained model based on a multi-slope integrated dataset to newly established monitoring slopes with limited or even no useful data,thus enabling rapid and efficient predictions for these ***,as time goes on and monitoring data accumulates,fine-tuning of the pre-trained model for individual slopes can further improve prediction accuracy,enabling continuous optimization of prediction results.A case study indicates that,after being trained on a multi-slope integrated dataset,the TCN-Transformer model can efficiently serve as a pretrained model for displacement prediction at newly established monitoring *** three-day average RMSE is significantly reduced by 34.6%compared to models trained only on individual slope data,and it also successfully predicts the majority of deformation *** fine-tuned model based on accumulated data on the target newly established monitoring slope further reduced the three-day RMSE by 37.2%,demonstrating a considerable predictive *** conclusion,taking advantage of transfer learning,the proposed slope displacement prediction method effectively utilizes the available data,which enables the rapid deployment and continual refinement of displacement predictions on newly established monitoring slopes.

关键词： Landslide Slope displacement prediction Transfer learning Integrated dataset Transformer Pre-trained model Universal Landslide Monitoring Program(ULMP) Geological hazards survey engineering

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Mandarin fish von Hippel-Lindau protein regulates the NF-κB signaling pathway via interaction with IκB to promote fish ranavirus replication

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Zoological Research 2024年第5期45卷 990-1000页

作者： Zhi-Min Li Xiao-Wei Qin Qi Zhang jian He Min-Cong Liang Chuan-Rui Li Yang Yu Weng-Hui Liu Shao-ping Weng jian-Guo He Chang-Jun Guo School of Marine Sciences State Key Laboratory for BiocontrolSouthern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Guangdong Province Key Laboratory of Aquatic Economic Animals&Guangdong Provincial Observation and Research Station for Marine Ranching of the Lingdingyang BaySun Yat-sen UniversityGuangzhouGuangdong 510275China Guangdong Laboratory for Lingnan Modern Agriculture South China Agricultural UniversityGuangzhouGuangdong 510640China

The von Hippel-Lindau tumor suppressor protein(VHL),an E3 ubiquitin ligase,functions as a critical regulator of the oxygen-sensing pathway for targeting hypoxia-inducible *** evidence suggests that mammalian VHL may also be critical to the NF-κB signaling pathway,although the specific molecular mechanisms remain ***,the roles of mandarin fish(Siniperca chuatsi)VHL(scVHL)in the NF-κB signaling pathway and mandarin fish ranavirus(MRV)replication were *** transcription of scVHL was induced by immune stimulation and MRV infection,indicating a potential role in innate ***-luciferase reporter gene assays and reverse transcription quantitative PCR(RT-qPCR)results demonstrated that scVHL evoked and positively regulated the NF-κB signaling *** with NF-κB signaling pathway inhibitors indicated that the role of scVHL may be mediated through scIKKα,scIKKβ,scIκBα,or ***-immunoprecipitation(Co-IP)analysis identified scIκBαas a novel target protein of ***,scVHL targeted scIκBαto catalyze the formation of K63-linked polyubiquitin chains to activate the NF-κB signaling *** MRV infection,NF-κB signaling remained activated,which,in turn,promoted MRV *** findings suggest that scVHL not only positively regulates NF-κB but also significantly enhances MRV *** study reveals a novel function of scVHL in NF-κB signaling and viral infection in fish.

关键词： VHL NF-κB IκBα Ranavirus Mandarin fish

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Triple points and phase transitions of D-dimensional dyonic Ad S black holes with quasitopological electromagnetism in Einstein–Gauss–Bonnet gravity

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Chinese Physics B 2024年第6期33卷 272-287页

作者：牟平辉蒋青权何柯腱李国平 School of Physics and Astronomy China West Normal UniversityNanchong 637000China College of Physics Chongqing UniversityChongqing 401331China

By considering the negative cosmological constant Λ as a thermodynamic pressure, we study the thermodynamics and phase transitions of the D-dimensional dyonic Ad S black holes(BHs) with quasitopological electromagnetism in Einstein–Gauss–Bonnet(EGB) gravity. The results indicate that the small/large BH phase transition that is similar to the van der Waals(vdW) liquid/gas phase transition always exists for any spacetime dimensions. Interestingly, we then find that this BH system exhibits a more complex phase structure in 6-dimensional case that is missed in other ***, it shows for D = 6 that we observed the small/intermediate/large BH phase transitions in a specific parameter region with the triple point naturally appeared. Moreover, when the magnetic charge turned off, we still observed the small/intermediate/large BH phase transitions and triple point only in 6-dimensional spacetime, which is consistent with the previous results. However, for the dyonic Ad S BHs with quasitopological electromagnetism in Einstein–Born–Infeld(EBI) gravity, the novel phase structure composed of two separate coexistence curves observed by Li et al. [Phys. Rev. D105 104048(2022)] disappeared in EGB gravity. This implies that this novel phase structure is closely related to gravity theories, and seems to have nothing to do with the effect of quasitopological electromagnetism. In addition, it is also true that the critical exponents calculated near the critical points possess identical values as mean field theory. Finally, we conclude that these findings shall provide some deep insights into the intriguing thermodynamic properties of the dyonic Ad S BHs with quasitopological electromagnetism in EGB gravity.

关键词： AdS black hole phase transition triple point

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