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Particle size dependence of the microsegregation and microstructure in the atomized Ni-based superalloy powders:Theoretical and experimental study

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Journal of Materials Science & Technology 2024年第4期171卷 54-65页

作者： Jikang Li Mingsheng Yang Yunfei Cai Yuanyuan Zhang Qingshuai Feng Jiantao liu tong liu Key Laboratory of Aerospace Materials and Performance(Ministry of Education)School of Materials Science and Engineering Beihang UniversityBeijing 100191China Central Iron and Steel Research Institute Beijing 100081China

The microstructure and microsegregation of atomized powder,which depend on their sizes,are of great importance to the mechanical properties of the consolidated bulk materials.Therefore,it is necessary to reveal the relationship between particle size and powder attributes.The effects of particle size on the so-lidification characterization of the atomized Ni-based superalloy powders were studied via finite element simulation.Based on the simulations,a model was developed to predict the microsegregation and mi-crostructure of atomized powders with different sizes and study the influence of thermal history on the powder attributes during the atomization processes.The radiation heat transfer and temperature gradi-ent within the rapid solidification alloy powders were taken into account in this model.For validating the accuracy of the model,the predictions of the present model were compared with the microsegregation and microstructure of the specific size powder close to the screen mesh size.The results showed that mi-crostructure depended primarily on the temperature gradient within the powder,while the solidification rate had a more significant effect on the microsegregation.The model predicted microstructure features in agreement with the experiment,and for microsegregation,the deviations of prediction for most ele-ments were less than 10%.This work provides a new model to precisely predict the microsegregation and microstructure of the atomized alloy powders and sets a foundation to control the powder features for various engineering applications.

关键词： Particle size Solidification microstructure Microsegregation Numerical simulation

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Rational Design of Ruddlesden-Popper Perovskite Ferrites as Air Electrode for Highly Active and Durable Reversible Protonic Ceramic Cells

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Nano-Micro Letters 2024年第9期16卷 308-324页

作者： Na Yu Idris Temitope Bello Xi Chen tong liu Zheng Li Yufei Song Meng Ni Department of Building and Real Estate Research Institute for Sustainable Urban Development(RISUD)and Research Institute for Smart Energy(RISE)The Hong Kong Polytechnic UniversityHung HomKowloonHong KongPeople’s Republic of China The Hong Kong Polytechnic University Shenzhen Research Institute Shenzhen 518057GuangdongPeople’s Republic of China Department of Mechanical and Aerospace Engineering The Hong Kong University of Science and TechnologyClear Water BayHong KongPeople’s Republic of China

Reversible protonic ceramic cells(RePCCs)hold promise for efficient energy storage,but their practicality is hindered by a lack of high-performance air electrode materials.Ruddlesden-Popper perovskite Sr_(3)Fe_(2)O_(7−δ)(SF)exhibits superior proton uptake and rapid ionic conduction,boosting activity.However,excessive proton uptake during RePCC operation degrades SF’s crystal structure,impacting durability.This study introduces a novel A/B-sites co-substitution strategy for modifying air electrodes,incorporating Sr-deficiency and Nb-substitution to create Sr_(2.8)Fe_(1.8)Nb_(0.2)O_(7−δ)(D-SFN).Nb stabilizes SF’s crystal,curbing excessive phase formation,and Sr-deficiency boosts oxygen vacancy concentration,optimizing oxygen transport.The D-SFN electrode demonstrates outstanding activity and durability,achieving a peak power density of 596 mW cm^(−2)in fuel cell mode and a current density of−1.19 A cm^(−2)in electrolysis mode at 1.3 V,650℃,with excellent cycling durability.This approach holds the potential for advancing robust and efficient air electrodes in RePCCs for renewable energy storage.

关键词： Reversible protonic ceramic cells Air electrode Ruddlesden-Popper perovskite Hydration Oxygen reduction reaction

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High-efficiency preparation of multifunctional conjugated electrospun graphene doped PVDF/CF yarns for energy harvesting and human movement monitoring in TENG textile

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Nano Research 2024年第5期17卷 4478-4488页

作者： Ting Yang Chengwei Wan Xiaoyu Zhang tong liu Li Niu Jian Fang Yuqing liu College of Textile and Clothing Engineering Soochow UniversitySuzhou 215123China

Portable power is an effective solution to realize self-powered sensors for wearable devices,promoting future sustainable development.Membrane-based triboelectric nanogenerators(M-TENGs)have emerged as a promising technology for harvesting biomechanical energy from human motion owing to their advantages,such as simple structure,lightweight design,and efficient energy conversion.However,the poor durability,low adaptability,and un-washability of two-dimensional membrane materials have largely hindered their application in wearable electronics.In this study,we propose a sheath-core polyvinylidene fluoride(PVDF)/graphene(G)-carbon fiber(CF)yarn fabricated via conjugate electrospinning,comprising a commercial CF core and an electrospun graphene-doped PVDF sheath,which improves the fatigue resistance of electrospun nanofiber films under prolonged friction and keeps a high degree of freedom.The resulting electronic textile,woven with the large-scale electrospun PVDF/G-CF yarn,demonstrates a remarkable power density of 25.5 mW·m^(-2).The tight distribution of PVDF/G nanofibers on the textile surface ensures excellent softness,washability,and durability.Furthermore,the electrospun PVDF/G-CF textile exhibits significant potential in pressure sensing,self-powered operation,and motion detection,making it highly suitable for wearable electronics applications.

关键词： yarn-based triboelectric nanogenerator(TENG) graphene polyvinylidene fluoride(PVDF) conjugated-electrospinning multifunctional

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Ash removal from inferior coal via ammonium fluoride roasting and simultaneous yield of white carbon black

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International Journal of Mining Science and Technology 2024年第2期34卷 261-279页

作者： Xuqin Duan Shuaiyu Lu Yuxiao Fu Jiazhe Zhang tong liu Jian Ma School of Civil and Resource Engineering University of Science&Technology BeijingBeijing 100083China State Key Laboratory for Efficient Mining of Metal Mines University of Science&Technology BeijingBeijing 100083China China Coal Processing and Utilizaiton Association Beijing 100013China

The quality upgrading and deashing of inferior coal by chemical method still faces great challenges.The dangers of strong acid,strong alkali,waste water and exhaust gas as well as high cost limit its industrial production.This paper systematically investigates the ash reduction and desilicification of two typical inferior coal utilizing ammonium fluoride roasting method.Under the optimal conditions,for fat coal and gas coal,the deashing rates are 69.02%and 54.13%,and the desilicification rates are 92.64%and 90.27%,respectively.The molar dosage of ammonium fluoride remains consistent for both coals;however,the gas coal,characterized by a lower ash and silica content(less than half that of the fat coal),achieves optimum deashing effect at a reduced time and temperature.The majority of silicon in coal transforms into gaseous ammonium fluorosilicate,subsequently preparing nanoscale amorphous silica with a purity of 99.90%through ammonia precipitation.Most of the fluorine in deashed coal are assigned in inorganic minerals,suggesting the possibility of further fluorine and ash removal via flotation.This research provides a green and facile route to deash inferior coal and produce nano-scale white carbon black simultaneously.

关键词： Inferior coal Deashing treatment Silicon recycling Ammonium fluoride roasting White carbon black

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Strategic Behavior Analysis and Modeling for Resilient Resource Allocation

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Journal of Systems Science and Information 2024年

作者： tong liu Saike HE University of Chinese Academy of Sciences China People's Police University State Key Laboratory of Multimodal Artificial Intelligence Systems Institute of Automation Chines Academy of Sciences

In an era where power systems face increased cyber threats, social media data, especially public sentiment during outages, emerges as a crucial component for devising defense strategies. We present a methodology that integrates sentiment analysis of social media data with advanced reinforcement learning techniques to tackle uncertain load redistribution cyberattacks. This approach first employs VADER and Support Vector Machine(SVM) sentiment analysis on collected social media data, revealing insightful information about power outages and public sentiment. Proximal Policy Optimization(PPO), a state-of-the-art reinforcement learning method, is then applied in the second stage to leverage these insights, manage outage uncertainty, and optimize defense strategies. The efficacy of this methodology is demonstrated on a modified IEEE 6-bus system. The results underscore our approach’s effectiveness in utilizing social media data for a nuanced, targeted response to cyberattacks.This pioneering methodology offers a promising direction for enhancing power grid resilience against cyberattacks and natural disasters, highlighting the value of social media sentiment analysis in power systems security.

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Hyperbranched polymer hollow-fiber-composite membranes for pervaporation separation of aromatic/aliphatic hydrocarbon mixtures

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Chinese Journal of Chemical Engineering 2024年第5期69卷 13-22页

作者： tong liu Hao Sun Xiangqiong Wang Jie Li Zhanquan Zhang Pei Wu Naixin Wang Quanfu An Beijing Key Laboratory for Green Catalysis and Separation Department of Chemical EngineeringCollege of Materials Science and EngineeringBeijing University of TechnologyBeijing 100124China Petrochemical Research Institute CNPCBeijing 102206China

The separation of aromatic/aliphatic hydrocarbon mixtures is crucial in the petrochemical industry.Pervaporation is regarded as a promising approach for the separation of aromatic compounds from alkanes. Developing membrane materials with efficient separation performance is still the main task since the membrane should provide chemical stability, high permeation flux, and selectivity. In this study, the hyperbranched polymer(HBP) was deposited on the outer surface of a polyvinylidene fluoride(PVDF)hollow-fiber ultrafiltration membrane by a facile dip-coating method. The dip-coating rate, HBP concentration, and thermal cross-linking temperature were regulated to optimize the membrane structure.The obtained HBP/PVDF hollow-fiber-composite membrane had a good separation performance for aromatic/aliphatic hydrocarbon mixtures. For the 50%/50%(mass) toluene/n-heptane mixture, the permeation flux of optimized composite membranes could reach 1766 g·m^(-2)·h^(-1), with a separation factor of 4.1 at 60℃. Therefore, the HBP/PVDF hollow-fiber-composite membrane has great application prospects in the pervaporation separation of aromatic/aliphatic hydrocarbon mixtures.

关键词： Aromatic/aliphatic hydrocarbons Hyperbranched polymer Pervaporation Hollow fiber membrane Dip-coating

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Protein C deficiency with venous and arterial thromboembolic events

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World Journal of Clinical Cases 2024年第12期12卷 2000-2003页

作者： Nan Zhang Dong-Kun Sun Xu Tian Xin-Yu Zheng tong liu Department of Cardiology Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular DiseaseTianjin Institute of CardiologyThe Second Hospital of Tianjin Medical UniversityTianjin 300211China

Protein C(PC)is a key component of the vitamin K-dependent coagulation pathway.It exerts anticoagulant effects by inactivating factors V and VIII.Acquired or inherited PC deficiency results in a prothrombotic state,with presentations varying from asymptomatic to venous thromboembolism.However,there has been an increasing number of reports linking PC deficiency to arterial thromboembolic events,such as myocardial infarction and ischemic stroke.This editorial focuses on the association between PC deficiency and thromboembolism,which may provide some insights for treatment strategy and scientific research.

关键词： Protein C deficiency Venous thromboembolism Myocardial infarction Editorial Arterial thromboembolism

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Non-radical activation of persulfate with Bi_(2)O_(3)/BiO_(1.3)I_(0.4)for efficient degradation of propranolol under visible light

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Journal of Environmental Sciences 2024年第8期142卷 57-68页

作者： Yuehua Deng Qianqian Che Yani Li Jiating Luo Xiang Gao Yan He Yiling liu tong liu Xiaolong Zhao Xiaobin Hu Wei Zhao College of Geology and Environment Xi’an University of Science and TechnologyXi’an 710054China Shaanxi Provincial Key Laboratory of Geological Support for Coal Green Exploitation Xi’an 710054China Department of Mechanical Engineering The University of Hong KongHong Kong 999077China School of Life Science Huzhou UniversityHuzhou 313000China School of Materials Engineering Changshu Institute of TechnologyChangshu 215500China

Non-radical activation of persulfate(PS)by photocatalysts is an effective approach for removing organic pollutants from aqueous environments.In this study,a novel Bi_(2)O_(3)/BiO_(1.3)I_(0.4)heterojunction was synthesized using a facile solvothermal approach and used for the first time for non-radical activation of PS to degrade propranolol(PRO)in the presence of visible light.The findings found that the degradation rate of PRO in the Bi_(2)O_(3)/BiO_(1.3)I_(0.4)/PS system was significantly increased from 19%to more than 90%within 90 min compared to the Bi_(2)O_(3)/BiO_(1.3)I_(0.4)system.This indicated that the composite system exerted an excellent synergistic effect between the photocatalyst and the persulfate-based oxygenation.Quenching tests and electron paramagnetic resonance demonstrated that the non-radical pathway with singlet oxygen as the active species played a major role in the photocatalytic process.The existence of photo-generated holes during the reaction could also be directly involved in the oxidation of pollutants.Meanwhile,a possible PRO degradation pathway was also proposed.Furthermore,the impacts of pH,humic acid and common anions on the PRO degradation by the Bi_(2)O_(3)/BiO_(1.3)I_(0.4)/PS were explored,and the system’s stability and reusability were also studied.This study exhibits a highly productive catalyst for PS activation via a non-radical pathway and provides a new idea for the degradation of PRO.

关键词： Iodine deficiency Heterojunction Persulfate(PS) Propranolol(PRO) Photocatalytic degradation

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Movement Function Assessment Based on Human Pose Estimation from Multi-View

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Computer Systems Science & Engineering 2024年第2期48卷 321-339页

作者： Lingling Chen tong liu Zhuo Gong Ding Wang School of Artificial Intelligence Hebei University of TechnologyTianjin300400China Intelligent Rehabilitation Device and Detection Technology Engineering Research Centre of the Ministry of Education Tianjin300400China

Human pose estimation is a basic and critical task in the field of computer vision that involves determining the position(or spatial coordinates)of the joints of the human body in a given image or video.It is widely used in motion analysis,medical evaluation,and behavior monitoring.In this paper,the authors propose a method for multi-view human pose estimation.Two image sensors were placed orthogonally with respect to each other to capture the pose of the subject as they moved,and this yielded accurate and comprehensive results of three-dimensional(3D)motion reconstruction that helped capture their multi-directional poses.Following this,we propose a method based on 3D pose estimation to assess the similarity of the features of motion of patients with motor dysfunction by comparing differences between their range of motion and that of normal subjects.We converted these differences into Fugl–Meyer assessment(FMA)scores in order to quantify them.Finally,we implemented the proposed method in the Unity framework,and built a Virtual Reality platform that provides users with human–computer interaction to make the task more enjoyable for them and ensure their active participation in the assessment process.The goal is to provide a suitable means of assessing movement disorders without requiring the immediate supervision of a physician.

关键词： Human pose estimation 3D pose reconstruction assessment of movement function plane of features of human motion

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Atorvastatin, etanercept and the nephrogenic cardiac sympathetic remodeling in chronic renal failure rats

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Journal of Geriatric Cardiology 2024年第4期21卷 443-457页

作者： Jing-Yue XU Zheng-Kai XUE Ya-Ru ZHANG Xing liu Xue ZHANG Xi YANG tong liu Kang-Yin CHEN Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease Department of CardiologyTianjin Institute of Cardiologythe Second Hospital of Tianjin Medical UniversityTianjinChina

BACKGROUND Chronic renal failure(CRF) patients are predisposed to arrhythmias, while the detailed mechanisms are unclear. We hypothesized the chronic inflammatory state of CRF patients may lead to cardiac sympathetic remodeling, increasing the incidence of ventricular arrhythmia(VA) and sudden cardiac death. And explored the role of atorvastatin and etanercept in this process.METHODS A total of 48 rats were randomly divided into sham operation group(Sham group), CRF group, CRF + atorvastatin group(CRF + statin group), and CRF + etanercept group(CRF + rhTNFR-Fcgroup). Sympathetic nerve remodeling was assessed by immunofluorescence of growth-associated protein 43(GAP-43) and tyrosine hydroxylase positive area fraction. Electrophysiological testing was performed to assess the incidence of VA by assessing the ventricular effective refractory period and ventricular fibrillation threshold. The levels of tumor necrosis factor-alpha(TNF-α) and interleukin-1beta were determined by Western blotting and enzyme-linked immunosorbent assay.RESULTS Echocardiogram showed that compared with the Sham group, left ventricular end-systolic diameter and ventricular weight/body weight ratio were significantly higher in the CRF group. Hematoxylin-eosin and Masson staining indicated that myocardial fibers were broken, disordered, and fibrotic in the CRF group. Western blotting, enzyme-linked immunosorbent assay,immunofluorescence and electrophysiological examination suggested that compared with the Sham group, GAP-43 and TNF-α proteins were significantly upregulated, GAP-43 and tyrosine hydroxylase positive nerve fiber area was increased, and ventricular fibrillation threshold was significantly decreased in the CRF group. The above effects were inhibited in the CRF + statin group and the CRF + rhTNFR-Fcgroup.CONCLUSIONS In CRF rats, TNF-α was upregulated, cardiac sympathetic remodeling was more severe, and the nephrogenic cardiac sympathetic remodeling existed. Atorvastatin and etanercept could downregulate the expression of TNF-α or inh

关键词： remodeling cardiac inhibited

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