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Numerical simulation of fluid flow and free surface fluctuations during wheel and belt casting process

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Journal of Iron and Steel Research(International) 2024年第5期31卷 1117-1126页

作者： kun Gao Yan Peng National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan UniversityQinhuangdao066004HebeiChina

The unstable fluid flow and severe free surface fluctuations in the wheel and belt caster can affect the quality of the cast *** lower level height tends to entrap inclusions in the molten *** the other hand,the higher level height makes the production process more dangerous due to the overflow of high temperature fluid from the mold.A computational model of the molten metal pouring process was *** transient fluid flow and free surface fluctuations behavior were calculated using the three-dimensional large eddy simulation model and the volume of fluid *** results show that the flow velocity of the main jet gradually decreases under the influence of the low kinetic energy fluid in the *** is an obvious oscillation in the tail of the jet,while the flow field is asymmetric in *** jet is closer to the inside radius side due to the Coanda effect,and there is a recirculation zone on the inside radius and the outside radius respectively,according to the 10 s time-averaged *** with the industrial observation and simulation results,the shape of the free surface is a wave that varies with *** addition,the free surface height is lowest and the flow velocity is highest in the region near the jet.

关键词： Fluid flow Free surface Wheel and belt caster Large eddy simulation Volume of fluid method

Flow instability of supercritical hydrocarbon fuel in a multi-channel cooling system

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Chinese Journal of Aeronautics 2024年第2期37卷 283-295页

作者： Yichao JIN kun WU Xuejun FAN Institute of Applied Physics and Computational Mathematics Beijing 100094China Institute of Mechanics Chinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

Thermally-induced flow instabilities are a critical issue in multi-channel regenerative cooling *** particular,the interactions between Density-Wave Oscillations(DWO)and Flow Maldistribution(FMD)can result in complex and disastrous instability *** study investigates the instability behaviors of hydrocarbon fluid in a four-channel system with a constant heat flux ratio using both frequency-and time-domain *** the heat flux increases,the in-tube flow sequentially destabilizes in each channel and converges to new equilibrium states,leading to the emergence of FMD *** also causes the system eigenvalue to change repeatedly from negative to positive rather than increasing ***,the system eigenvalues are between those of the two most unstable channels,indicating that the stability behavior of the entire system is dictated by the most unstable *** FMD occurs,flow oscillations are activated in channels with weak stability,and the in-tube flow is observed to evolve into various flow patterns,including stable flow,self-sustained oscillation,oscillation divergence,quasiperiodic oscillation,and oscillation *** novel instability mode of oscillation excursion involves a spontaneous transition of operating *** oscillates from an equilibrium state and then stabilizes at a new operational state after oscillation-induced ***,the newfound stable state may also be only temporary,with the in-tube flow regressing to the initial state,resulting in quasi-periodic oscillation.

关键词： Cooling Supercritical fluids Hydrocarbons Flow instability Flow maldistribution Density-wave oscillations

A Fair and Trusted Trading Scheme for Medical Data Based on Smart Contracts

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Computers, Materials & Continua 2024年第2期78卷 1843-1859页

作者： Xiaohui Yang kun Zhang School of Cyber Security and Computer Hebei UniversityBaoding071000China

Data is regarded as a valuable asset,and sharing data is a prerequisite for fully exploiting the value of ***,the current medical data sharing scheme lacks a fair incentive mechanism,and the authenticity of data cannot be guaranteed,resulting in low enthusiasm of participants.A fair and trusted medical data trading scheme based on smart contracts is proposed,which aims to encourage participants to be honest and improve their enthusiasm for *** scheme uses zero-knowledge range proof for trusted verification,verifies the authenticity of the patient’s data and the specific attributes of the data before the transaction,and realizes privacy *** the same time,the game pricing strategy selects the best revenue strategy for all parties involved and realizes the fairness and incentive of the transaction *** smart contract is used to complete the verification and game bargaining process,and the blockchain is used as a distributed ledger to record the medical data transaction process to prevent data tampering and transaction ***,by deploying smart contracts on the Ethereum test network and conducting experiments and theoretical calculations,it is proved that the transaction scheme achieves trusted verification and fair bargaining while ensuring privacy protection in a decentralized *** experimental results show that the model improves the credibility and fairness of medical data transactions,maximizes social benefits,encourages more patients and medical institutions to participate in the circulation of medical data,and more fully taps the potential value of medical data.

关键词： Blockchain data transactions zero-knowledge proof game pricing

Hippocampal dopamine as a key regulator for learning deficits in Parkinson's disease

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Neural Regeneration Research 2024年第6期19卷 1193-1194页

作者： kun Wu Shuai Liu Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education) Affiliated Mental Health Center (ECNU) School of Psychology and Cognitive Science East China Normal University Shanghai Changning Mental Health Center NYU-ECNU Institute of Brain and Cognitive Science at NYU Shanghai

Parkinson’s disease(PD) is a progressive neurodegenerative disorder with clinical symptoms of involuntary or uncontrollable movements such as tremors,rigidity,and *** learning deficit is largely overlooked in the pas... 详细信息

关键词： MEMORY

Sub-nanosized vanadate hybrid clusters maintain glucose homeostasis and restore treatment response in inflammatory disease in obese mice

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Nano Research 2024年第3期17卷 1818-1826页

作者： kun Chen Shengqiu Liu Yujun Wei South China Advanced Institute for Soft Matter Science and Technology School of Emergent Soft MatterSouth China University of TechnologyGuangzhou 510641China Guangdong Provincial Key Laboratory of Technique and Equipment for Macromolecular Advanced Manufacturing South China University of TechnologyGuangzhou 510641China Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices South China University of TechnologyGuangzhou 510641China

Obesity is closely related with insulin resistance and chronic ***,we report that unsaturated lipid-modified polyoxovanadates(ULPOVs)can restrict weight gain of diet-induced obese mice and improve their glycemic control and obesity-associated *** administration of the sub-nanosized ULPOVs at a low dosage for 7 weeks reduces the body weight and almost normalizes the blood glucose levels of obese mice fed on a high-fat *** treatment increases the activity of the nuclear receptor peroxisome proliferator-activated receptorγ(PPARγ)and reduces intestinal caloric intake,which may be the main reason for blood sugar and body weight *** addition to insulin-sensitizing,PPARγactivation induced by ULPOV treatment in obese mice with atopic dermatitis(AD)promotes the type 2 T helper(TH_(2))cell selective responses and therapeutic effects on immune dysregulation caused by *** data suggest sub-nanosized polyoxovanadate clusters as a class of potential candidates to relieve symptoms accompanied by diet-induced obesity.

关键词： polyoxovanadates lipid modification glucose homeostasis obesity inflammatory disease peroxisome proliferator-activated receptorγ(PPARγ)

Tensor perturbations from bounce inflation scenario in f(Q)gravity

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Science China(Physics,Mechanics & Astronomy) 2024年第2期67卷 78-92页

作者： kun Hu Tanmoy Paul Taotao Qiu Institute of Astrophysics Central China Normal UniversityWuhan 430079China School of Physics Huazhong University of Science and TechnologyWuhan 430074China National Institute of Technology Jamshedpur Department of PhysicsJamshedpur 831014India

In this paper,we construct a bounce inflation cosmological scenario in the framework of the modified symmetric teleparallel gravity,namely f(Q)theory,and investigate the tensor perturbations *** is well-known,the tensor perturbations generated in the very early Universe(inflation and pre-inflation regions)can account for the primordial gravitational waves(PGWs)that are to be detected by the next generation of GW *** discuss the stability condition of the tensor perturbations in the bounce inflation process and investigate in detail the evolution of the perturbation *** general form of the tensor power spectrum is obtained both for large as well as small scale *** a result,we show both kinds of modes(short or long wavelength modes),and the tensor spectrum may get a positive tilt in the parametric range where the tensor perturbation proves to be stable—this interestingly hints an enhancement of gravitational waves’amplitude in the background of the f(Q)bounce-inflation ***,we study the LQC-like scenario as a specific case of our model,in which,the primordial tensor power spectrum turns out to be nearly scale-invariant on both small and large scales.

关键词： bounce cosmology modified gravity cosmological perturbations

Adaptive Consensus of Uncertain Multi-Agent Systems With Unified Prescribed Performance

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1310-1312页

作者： kun Li Kai Zhao Yongduan Song The authors are with the School of Automation Chongqing UniversityChongqing 400044China

Dear Editor,An adaptive consensus control algorithm for uncertain multi-agent systems(MAS),capable of guaranteeing unified prescribed performance,is presented in this *** many existing prescribed performance related works,the developed control exhibits some ***,a distributed prescribed time observer is introduced so that not only each follower is able to estimate the leader’s signal within a predetermined time,but also the control design for each agent is independent with its neighbors.

关键词： agent prescribed Uncertain

Cell replacement with stem cell-derived retinal ganglion cells from different protocols

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Neural Regeneration Research 2024年第4期19卷 807-810页

作者： Ziming Luo kun-Che Chang Spencer Center for Vision Research Byers Eye InstituteStanford University School of Medicine Department of Ophthalmology Louis J.Fox Center for Vision RestorationUniversity of Pittsburgh School of Medicine Department of Neurobiology Center of NeuroscienceUniversity of Pittsburgh School of Medicine

Glaucoma,characterized by a degenerative loss of retinal ganglion cells,is the second leading cause of blindness *** is currently no cure for vision loss in glaucoma because retinal ganglion cells do not regenerate and are not replaced after *** stem cell-derived retinal ganglion cell transplant is a potential therapeutic strategy for retinal ganglion cell degenerative *** this review,we first discuss a 2D protocol for retinal ganglion cell differentiation from human stem cell culture,including a rapid protocol that can generate retinal ganglion cells in less than two weeks and focus on their transplantation ***,we discuss using 3D retinal organoids for retinal ganglion cell transplantation,comparing cell suspensions and *** review provides insight into current knowledge on human stem cell-derived retinal ganglion cell differentiation and transplantation,with an impact on the field of regenerative medicine and especially retinal ganglion cell degenerative diseases such as glaucoma and other optic neuropathies.

关键词： cell clumps cell suspension cell transplantation differentiation direct-induced protocol glaucoma optic neuropathy regenerative medicine retinal ganglion cell retinal organoids stem cells

Generalized Inverses and Units in a Unitary Ring

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Acta Mathematica Sinica,English Series 2024年第4期40卷 1000-1014页

作者： Yu kun ZHOU Jian Long CHEN School of Mathematics Southeast UniversityNanjing 210096P.R.China

Let R be a unitary ring and a,b∈R with ab=*** find the 2/3 property of Drazin invertibility:if any two of a,b and a+b are Drazin invertible,then so is the third ***,we combine the 2/3 property of Drazin invertibility to characterize the existence of generalized inverses by means of *** applications,the need for two invertible morphisms used by You and Chen to characterize the group invertibility of a sum of morphisms is reduced to that for one invertible morphism,and the existence and expression of the inverse along a product of two regular elements are obtained,which generalizes the main result of Mary and Patricio(2016)about the group inverse of a product.

关键词： Leftπ-regular element stronglyπ-regular element group inverse Drazin inverse inverse along an element