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Numerical simulation of coupling multi-physical field in electrical arc furnace for smelting titanium slag

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Journal of Iron and Steel Research International 2023年第11期30卷 2194-2209页

作者： He-nan Cui Tao Li Chen-guang Bai Min Tan yu-lin zhu College of Materials Science and Engineering Chongqing UniversityChongqing400044China Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and Advanced Materials Chongqing UniversityChongqing400044China College of Metallurgy and Energy North China University of Science and TechnologyTangshan063210HebeiChina

The smelting reduction process of the ilmenite in an electric arc furnace(EAF)is a commonly used technology for producing titanium slag in the *** has particular significance to analyze the velocity-temperature-electromagnetics multi-physical field in an EAF for improving its productivity and reducing energy consumption.A transient three-dimensional mathematical model was developed to characterize the flow,heat transfer,and electromagnetic behavior in a titanium slag *** describing the electromagnetic field and its effects on velocity and temperature distribution in the furnace,magnetohydrodynamic equations and conservation equations for mass,momentum,and energy were solved simultaneously by compiling the user-defined function *** numerical model was verified by comparing with the literature *** results indicate that the Lorentz force is the main driving force of the velocity and temperature ***,the influence of input current and location of electrodes on the multi-physical field distribution was also *** is found that the appropriate range of input current and diameter of pitch circle are about 30,000 A and 3000-3500 mm,*** mathematical model established can characterize the multi-physical field more accu-rately than before,which can provide valuable guidance for the operation improvement and design optimization of the EAF for producing titanium slag.

关键词： Electric arc furnace Titanium slag Magnetohydrodynamic Multi-physical field User-defined function

Subtle Effect of Alkyl Substitutedπ-Bridges on Dibenzo[a,c]phenazine Based Polymer Donors towards Enhanced Photovoltaic Performance

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Chinese Journal of Polymer Science 2022年第8期40卷 889-897,I0007页

作者： Chun-Xian Ke Xue Lai Heng-Tao Wang Ming-Rui Pu Tahir Rehman yu-lin zhu Feng He Shenzhen Grubbs Institute and Department of Chemistry Southern University of Science and TechnologyShenzhen518055China Guangdong Provincial Key Laboratory of Catalysis Southern University of Science and TechnologyShenzhen518055China

Selection of the strategically substituted alkyl chains has a significant effect to modulate the physical properties of conjugated polymers,electro-optical characteristics,and active layer morphology of the corresponding polymer solar cells(PSCs).Herein,we systematically synthesized three dibenzo[a,c]phenazine based D-π-A donor polymers named PBP-C0,PBP-C8,and PBP-C6 with different alkyl substitutions on thiopheneπ-bridges,without alkyl,2-ethylhexyl and n-hexyl groups,*** absence of the alkyl chain(PBP-C0)on theπ-bridge caused poor solubility and unfavorable miscibility with the Y5 acceptor,leading to the lower photovoltaic *** bulky alkyl chain of 2-ethylhexyl on theπ-bridge group caused the twisting of PBP-C8 conjugated backbone,which limits the charge transport and also compromises the photovoltaic *** contrast,the PBP-C6-with flexible linear alkyl chains has almost planar curvature geometry resulting in the small uniform domain size and appropriate phase separation in the blend film *** favorable properties enhanced the exciton generation to dissociation,charge carrier mobility,and also lowered the charge *** three polymers,PBP-C6-based devices exhibit the best PCE of 11.60%.From these results,thiopheneπ-bridge alkyl substitution demonstrated an important strategy to adjust energy level,absorption,and phase separation morphology to enhance the photovoltaic performance of the PSCs.

关键词： π-Bridge Alkyl chain engineering Phenazine Polymer donor Polymer solar cell

Paleoenvironmental reconstruction and organic matter accumulation of the paleogene shahejie oil shale in the Zhanhua Sag, Bohai Bay Basin, Eastern China

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Petroleum Science 2024年第3期21卷 1552-1568页

作者： Xiao-lin Wang Xiao-Min zhu Jin Lai Xing-yue lin Xiang Wang yu-Shan Du Chao Huang yu-Rui zhu State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing102249China College of Geosciences China University of Petroleum(Beijing)Beijing102249China Shengli Oilfield SINOPECDongying257000ShandongChina

The controlling factors of organic-rich shale accumulation is essential for the exploration and development of shale oil and gas *** sedimentary environment plays a vital role in the formation of organic-rich sediments in lacustrine *** article unravels the mineralogy,geochemistry,and paleoenvironmental evolution during the deposition of the Paleogene Shahejie Formation(Es_(3)^(L)).It discusses the effects of paleoclimate,paleosalinity,paleoredox conditions,paleowater depth,and paleoproductivity on organic matter(OM)***,the OM enrichment model was *** results show that the mineralogical compositions are mainly composed of calcite(avg.40.13%),quartz(avg.21.64%)and clay minerals(avg.24.07%),accompanied by dolomite(avg.7.07%),feldspar(avg.6.36%)and pyrite(avg.2.95%).The Es_(3)^(L) shale has a high abundance of OM,with total organic carbon(TOC)ranging from 1.07%to 5.12%.The organic matter type is mainly composed of type I-II_(1) kerogen,which is generally considered a good-quality source *** source of OM is a mixture of lower bacteria,algae,and *** the early sedimentary period,the paleoclimate was dry and cold,with high salinity,intense reducibility,and relatively low *** the late sedimentary period,the climate became warmer and more *** a result,the salinity decreased to a level that was suitable for biological reproduction,and productivity increased gradually due to the input of terrigenous *** and paleoclimate determined the environment of the sedimentary period,in addition,paleoproductivity and paleoredox condition indicated the formation and preservation conditions of *** warm and humid climate,brackish water,suitable reduction conditions and high productivity are the favorable conditions for the generation and preservation of organic *** research results may have implications for the genetic mechanisms of organic matter *** will provide theoret

关键词： Elemental geochemical Paleoenvironment Organic matter accumulation Paleogene shahejie formation Zhanhua Sag Bohai Bay Basin

Sexual Dimorphism and Female Reproductive Characteristics in the Hainan Water Skink(Tropidophorus hainanus)from Hainan,South China

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Asian Herpetological Research 2024年第1期15卷 49-58页

作者： yu DU Xiaming zhu Chixian lin yuntao YAO Xiang JI Hainan Key Laboratory for Herpetological Research College of Fisheries and Life SciencesHainan Tropical Ocean UniversitySanya 572022HainanChina Zhejiang Provincial Key Laboratory for Water Environment and Marine Biological Resources Protection College of Life and Environmental SciencesWenzhou UniversityWenzhou 325035ZhejiangChina Institute for Eco-environmental Research of Sanyang Wetland Wenzhou UniversityWenzhou 325014ZhejiangChina

We studied sexual dimorphism in body size and shape and female reproductive characteristics in the Hainan Water Skink(Tropidophorus hainanus)from Hainan,South *** our sample the largest female and male were 61.1 and 55.2 mm snout-vent length(SVL),*** mean SVL was larger in adult females(52.0 mm)than in adult males(48.3 mm).Juveniles were sexually dimorphic in head length but not in other examined morphological *** males were longer in head length and shorter in abdomen length and fore-limb length than adult females of the same *** shifts in sexual dimorphism in body shape were evident,as revealed by the fact that morphological differences between the sexes were more pronounced in adults than in *** produced a single litter of 3–6 offspring per season from early August to early *** size,litter mass and offspring(neonate)mass were positively related to female *** mass was independent of relative *** the above findings we draw three main ***,females are the larger sex in ***,and sexual dimorphism in body shape is more pronounced in adults than in ***,larger female *** produce more and larger offspring and thus heavier litters than smaller ***,the offspring size-number trade-off does is not evident in ***.

关键词： fecundity morphology offspring size-number trade-off reproduction scincidae sexual dimorphism

A Composite Transformer-Based Multi-Stage Defect Detection Architecture for Sewer Pipes

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Computers, Materials & Continua 2024年第1期78卷 435-451页

作者： Zifeng yu Xianfeng Li Lianpeng Sun Jinjun zhu Jianxin lin School of Computer Science and Engineering Macao University of Science and TechnologyMacao999078China School of Environmental Science and Engineering Sun Yat-sen UniversityGuangzhou510275China Guangdong AIKE Environmental Science and Technology Co. Ltd.Zhongshan528400China

Urban sewer pipes are a vital infrastructure in modern cities,and their defects must be detected in time to prevent potential *** recent years,to relieve the manual efforts by human experts,models based on deep learning have been introduced to automatically identify potential ***,these models are insufficient in terms of dataset complexity,model versatility and *** work addresses these issues with amulti-stage defect detection architecture using a composite backbone Swin *** based on this architecture is trained using a more comprehensive dataset containingmore classes of *** ablation studies on the modules of combined backbone Swin Transformer,multi-stage detector,test-time data augmentation and model fusion,it is revealed that they all contribute to the improvement of detection accuracy from different *** model incorporating all these modules achieves the mean Average Precision(mAP)of 78.6% at an Intersection over Union(IoU)threshold of *** represents an improvement of 14.1% over the ResNet50 Faster Region-based Convolutional Neural Network(R-CNN)model and a 6.7% improvement over You Only Look Once version 6(YOLOv6)-large,the highest in the YOLO *** addition,for other defect detection models for sewer pipes,although direct comparison with themis infeasible due to the unavailability of their private datasets,our results are obtained from a more comprehensive dataset and have superior generalization capabilities.

关键词： Sewer pipe defect detection deep learning model optimization composite transformer

Study on the optimal incident proton energy of ^(7)Li(p,n)^(7)Be neutron source for boron neutron capture therapy

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Nuclear Science and Techniques 2024年第3期35卷 170-180页

作者： Yi-Nan zhu Zuo-Kang lin Hai-Yan yu Ye Dai Zhi-Min Dai Xiao-Han yu Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Science Beijing 100049China

Boron neutron capture therapy(BNCT)is recognized as a precise binary targeted radiotherapy technique that effectively eliminates tumors through the^(10)B(n,α)^(7)Li nuclear *** various neutron sources,accelerator-based sources have emerged as particularly promising for BNCT ***^(7)Li(p,n)^(7)Be reaction is highly regarded as a potential neutron source for BNCT,owing to its low threshold energy for the reaction,significant neutron yield,appropriate average neutron energy,and additional *** study utilized Monte Carlo simulations to model the physical interactions within a lithium target subjected to proton bombardment,including neutron moderation by an MgF_(2)moderator and subsequent BNCT dose analysis using a Snyder head *** study focused on calculating the yields of epithermal neutrons for various incident proton energies,finding an optimal energy at 2.7 ***,the Snyder head phantom was employed in dose simulations to validate the effectiveness of this specific incident energy when utilizing a^(7)Li(p,n)^(7)Be neutron source for BNCT purposes.

关键词： Boron neutron capture therapy ^(7)Li(p,n)7Be neutron source Incident proton energy Monte Carlo simulation

Switchable instantaneous frequency measurement by optical power monitoring based on DP-QPSK modulator

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Chinese Physics B 2022年第4期31卷 336-347页

作者： yu-lin zhu Bei-Lei Wu Jing Li Mu-Guang Wang Shi-Ying Xiao Feng-Ping Yan Institute of Lightwave Technology Key Laboratory of All Optical Network and Advanced Telecommunication of EMCBeijing Jiaotong UniversityBeijing 100044China

We propose and analyze an instantaneous frequency measurement system by using optical power monitoring technique with improved *** primary component adopted in the proposal is a dual-polarization quadrature phase shift keying(DP-QPSK) modulator which is used to modulate the microwave signal that has a designed time delay and phase *** generated optical signal is sent to polarization beam splitter(PBS) in DP-QPSK *** to the complementary transmission nature of polarization interference introduced by PBS,the frequency information is converted into the optical power and the relationship between the amplitude comparison function(ACF) and microwave frequency to be measured is ***,the frequency of the microwave signal can be easily measured through monitoring the optical powers of the two output ports of the ***,by adjusting the direct current(DC) biases of the DP-QPSK modulator instead of changing the electrical delay,the measurement range and resolution can be *** this paper,the basic principle of the instantaneous frequency measurement system is derived in detail,and simulation has been performed to investigate the resolution,the measurement range,and the influence of imperfection *** proposed scheme is wavelength-independent and its measurement range is switchable,which can avoid the laser wavelength drifting problem and thus greatly increasing the system flexibility.

关键词： microwave photonics DP-QPSK modulator instantaneous frequency measurement

Topological Stability and Entropy for Certain Set-valued Maps

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Acta Mathematica Sinica,English Series 2024年第4期40卷 962-984页

作者： yu ZHANG yu Jun zhu School of Mathematical Sciences Xiamen UniversityXiamen 361005P.R.China

In this paper,the dynamics(including shadowing property,expansiveness,topological stability and entropy)of several types of upper semi-continuous set-valued maps are mainly considered from differentiable dynamical systems points of *** is shown that(1)if f is a hyperbolic endomorphism then for eachε>0 there exists a C^(1)-neighborhood U of f such that the induced set-valued map F_(f,U)has theε-shadowing property,and moreover,if f is an expanding endomorphism then there exists a C^(1)-neighborhood U of f such that the induced set-valued map F_(f,U)has the Lipschitz shadowing property;(2)when a set-valued map F is generated by finite expanding endomorphisms,it has the shadowing property,and moreover,if the collection of the generators has no coincidence point then F is expansive and hence is topologically stable;(3)if f is an expanding endomorphism then for eachε>0 there exists a C^(1)-neighborhood U of f such that h(F_(f,U,ε))=h(f);(4)when F is generated by finite expanding endomorphisms with no coincidence point,the entropy formula of F is ***,the dynamics of the set-valued maps based on discontinuous maps on the interval are also considered.

关键词： Set-valued map orbit space hyperbolic endomorphism perturbation shadowing expansiveness topological stability entropy

Privacy-Preserving Federated Mobility Prediction with Compound Data and Model Perturbation Mechanism

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China Communications 2024年第3期21卷 160-173页

作者： Long Qingyue Wang Huandong Chen Huiming Jin Depeng zhu lin yu Li Li Yong Beijing National Research Center for Information Science and Technology(BNRist) Department of Electronic EngineeringTsinghua UniversityBeijing 100084China China Mobile Research Beijing 100032China

Human mobility prediction is important for many ***,training an accurate mobility prediction model requires a large scale of human trajectories,where privacy issues become an important *** rising federated learning provides us with a promising solution to this problem,which enables mobile devices to collaboratively learn a shared prediction model while keeping all the training data on the device,decoupling the ability to do machine learning from the need to store the data in the ***,existing federated learningbased methods either do not provide privacy guarantees or have vulnerability in terms of privacy *** this paper,we combine the techniques of data perturbation and model perturbation mechanisms and propose a privacy-preserving mobility prediction algorithm,where we add noise to the transmitted model and the raw data collaboratively to protect user privacy and keep the mobility prediction *** experimental results show that our proposed method significantly outperforms the existing stateof-the-art mobility prediction method in terms of defensive performance against practical attacks while having comparable mobility prediction performance,demonstrating its effectiveness.

关键词： federated learning mobility prediction privacy