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Effects of cooling rate on microstructure and microhardness of directionally solidified Galvalume alloy

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China Foundry 2024年第3期21卷 213-220页

作者： ji-peng li De-gao Qiao jian li Xiao-yang Luo peng peng Xian-tao Yan Xu-dong Zhang Gansu jiu Steel Group Hongxing Iron and Steel Co. Ltd.Jiayuguan 735111GansuChina School of Materials and Energy Lanzhou UniversityLanzhou 730000China

The influences of cooling rate on the phase constitution,microstructural length scale,and microhardness of directionally solidified Galvalume(Zn-55Al-1.6Si)alloy were investigated by directional solidification experiments at different withdrawal speeds(5,10,20,50,100,200,and 400μm·s^(-1)).The results show that the microstructure of directionally solidified Galvalume alloys is composed of primary Al dendrites,Si-rich phase and(Zn-Al-Si)ternary eutectics at the withdrawal speed ranging from 5 to 400μm·s^(-1).As the withdrawal speed increases,the segregation of Si element intensifies,resulting in an increase in the area fraction of the Si-rich phase.In addition,the primary Al dendrites show significant refinement with an increase in the withdrawal speed.The relationship between the primary dendrite arm spacing(λ_(1))and the thermal parameters of solidification is obtained:λ_(1)=127.3V^(-0.31).Moreover,as the withdrawal speed increases from 5 to 400μm·s^(-1),the microhardness of the alloy increases from 90 HV to 151 HV.This is a combined effect of grain refinement and second-phase strengthening.

关键词： Galvalume alloy directional solidification microstructure length scale microhardness

Unknown system dynamics estimator-based impedance control for lower limb exoskeleton with enhanced performance

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Control Theory and Technology 2024年第1期22卷 56-68页

作者： Wenhao Zhang peng Song Mingying Wu Qiang li Xinmin Mo Pingxin ji Northwest Institute of Mechanical and Electrical Engineering Xianyang712099ShaanxiChina Xi’an Exo-Smart Dynamics Technology Ltd. Xi’an712046ShaanxiChina Department of Mechanical and Engineering Beijing Institute of TechnologyBeijing100081China

In this article, an unknown system dynamics estimator-based impedance control method is proposed for the lower limb exoskeleton to stimulate the tracking flexibility with the terminal target position when suffering parametric inaccuracies and unexpected disturbances. To reinforce the robust performance, via constructing the filtering operation-based dynamic relation, i.e., invariant manifold, the unknown system dynamics estimators are employed to maintain the accurate perturbation identification in both the hip and knee subsystem. Besides, a funnel control technique is designed to govern the convergence process within a minor overshoot and a higher steady-state precision. Meanwhile, an interactive complaint result can be obtained with the aid of the impedance control, where the prescribed terminal trajectory can be adjusted into the interaction variable-based target position by the force–position mapping, revealing the dynamic influence between the impedance coefficient (stiffness and damping) and the adjusted position magnitude. A sufficient stability analysis verifies the ultimately uniformly bounded results of all the error signals, and even the angle errors can be regulated within the predefined funnel boundary in the whole convergence. Finally, some simulations are provided to demonstrate the validity and superiority including the enhanced interaction flexibility and robustness.

关键词： Trajectory tracking Invariant manifold Funnel control Impedance control Lower limb exoskeleton

Impact of an oligosaccharide-based polymer on the metabolic profiles and microbial ecology of weanling pigs experimentally infected with a pathogenic E.coli

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Journal of Animal Science and Biotechnology 2024年第2期15卷 749-764页

作者： Kwangwook Kim Cynthia jinno Xunde li David Bravo Eric Cox peng ji Yanhong liu Department of Animal Science University of CaliforniaDavisCA 95616USA Department of Animal Science Michigan State UniversityEast LansingMI 48824USA Cedars-Sinai Medical Center Los AngelesCA 90084USA School of Veterinary Medicine University of CaliforniaDavisCA 95616USA Pancosma|ADM 1180 RolleSwitzerland Nutreco Exploration NutrecoThe Netherlands Department of Virology Parasitology and ImmunologyGhent University9000 GhentBelgium Department of Nutrition University of CaliforniaDavisCA 95616USA

Background Our previous study has reported that supplementation of oligosaccharide-based polymer enhances gut health and disease resistance of pigs infected with enterotoxigenic E.coli(ETEC)F18 in a manner similar to carbadox.The objective of this study was to investigate the impacts of oligosaccharide-based polymer or antibiotic on the host metabolic profiles and colon microbiota of weaned pigs experimentally infected with ETEC F18.Results Multivariate analysis highlighted the differences in the metabolic profiles of serum and colon digesta which were predominantly found between pigs supplemented with oligosaccharide-based polymer and antibiotic.The relative abundance of metabolic markers of immune responses and nutrient metabolisms,such as amino acids and carbohydrates,were significantly differentiated between the oligosaccharide-based polymer and antibiotic groups(q2.0).In addition,pigs in antibiotic had a reduced(Pligosaccharide-based polymer on the metabolic and microbial profiles of pigs is not fully understood,and further exploration is needed.However,current research suggest that various mechanisms are involved in the enhanced disease resistance and performance in ETEC-challenged pigs by supplementing this polymer.

关键词： Carbadox Colon microbiota Enterotoxigenic E.coli F18 Metabolomics Oligosaccharide-based polymer Weaned pigs

Semi-derived Ringel-Hall algebras and Hall algebras of odd-periodic relative derived categories

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Science China Mathematics 2024年第8期67卷 1735-1760页

作者： ji lin liangang peng Department of Mathematics and Statistics Fuyang Normal University School of Mathematics Sichuan University

Let t be a positive integer and A be a hereditary abelian category satisfying some finiteness conditions. We define the semi-derived Ringel-Hall algebra of A from the category CZ/t（A） of Z/t-graded complexes and obtain a natural basis of the semi-derived Ringel-Hall algebra. Moreover, we describe the semiderived Ringel-Hall algebra by the generators and defining relations. In particular, if t is an odd integer, we show an embedding of the derived Hall algebra of the odd-periodic relative derived category in the extended semi-derived Ringel-Hall algebra.

关键词： hereditary abelian categories the categories of $\mathbb{Z}/t$-graded complexes semi-derived Ringel-Hall algebras derived Hall algebras

Mechanical reliable,NIR light-induced rapid self-healing hydrogel electrolyte towards flexible zinc-ion hybrid supercapacitors with low-temperature adaptability and long service life

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Journal of Energy Chemistry 2024年第5期92卷 63-73页

作者： Tengjia Gao Na li Yang Yang jing li peng ji Yunlong Zhou jianxiong Xu School of Materials and Advanced Manufacturing Hunan Key Laboratory of Electrochemical Green Metallurgy TechnologyHunan University of TechnologyZhuzhou 412007HunanChina School of life Sciences and Chemistry Hunan Key Laboratory of Biomedical Nanomaterials and DevicesHunan University of TechnologyZhuzhou 412007HunanChina

Hydrogel electrolytes hold great potential in flexible zinc ion supercapacitors(ZICs)due to their high conductivity,good safety,and flexibility.However,freezing of electrolytes at low temperature(subzero)leads to drastic reduction in ionic conductivity and mechanical properties that deteriorates the performance of flexible ZICs.Besides,the mechanical fracture during arbitrary deformations significantly prunes out the lifespan of the flexible device.Herein,a Zn^(2+)and li^(+)co-doped,polypyrrole-dopamine decorated Sb_(2)S_(3)incorporated,and polyvinyl alcohol/poly(N-(2-hydroxyethyl)acrylamide)double-network hydrogel electrolyte is constructed with favorable mechanical reliability,anti-freezing,and self-healing ability.In addition,it delivers ultra-high ionic conductivity of 8.6 and 3.7 S m^(-1)at 20 and−30°C,respectively,and displays excellent mechanical properties to withstand tensile stress of 1.85 MPa with tensile elongation of 760%,together with fracture energy of 5.14 MJ m^(-3).Notably,the fractured hydrogel electrolyte can recover itself after only 90 s of infrared illumination,while regaining 83%of its tensile strain and almost 100%of its ionic conductivity during−30–60°C.Moreover,ZICs coupled with this hydrogel electrolyte not only show a wide voltage window(up to 2 V),but also provide high energy density of 230 Wh kg^(-1)at power density of 500 W kg^(-1)with a capacity retention of 86.7%after 20,000 cycles under 20°C.Furthermore,the ZICs are able to retain excellent capacity even under various mechanical deformation at−30°C.This contribution will open up new insights into design of advanced wearable flexible electronics with environmental adaptability and long-life span.

关键词： Flexible zinc ion supercapacitor Hydrogel electrolyte Self-healing Anti-freezing

A thermodynamic view on the in-situ carbon dioxide reduction by biomass-derived hydrogen during calcium carbonate decomposition

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Chinese Journal of Chemical Engineering 2024年第4期68卷 231-240页

作者： peng jiang Hao Zhang Guanhan Zhao lin li Tuo ji liwen Mu Xiaohua Lu jiahua Zhu State Key Laboratory of Materials-oriented Chemical Engineering College of Chemical EngineeringNanjing Tech UniversityNanjing 211816China

In the carbonate industry,deep decarbonization strategies are necessary to effectively remediate CO_(2).These strategies mainly include both sustainable energy supplies and the conversion of CO_(2)in downstream processes.This study developed a coupled process of biomass chemical looping H2 production and reductive calcination of CaCO_(3).Firstly,a mass and energy balance of the coupled process was established in Aspen Plus.Following this,process optimization and energy integration were implemented to provide optimized operation conditions.Lastly,a life cycle assessment was carried out to assess the carbon footprint of the coupled process.Results reveal that the decomposition temperature of CaCO_(3)in an H_(2)atmosphere can be reduced to 780℃(generally around 900℃),and the conversion of CO_(2)from CaCO_(3)decomposition reached 81.33%with an H2:CO ratio of 2.49 in gaseous products.By optimizing systemic energy through heat integration,an energy efficiency of 86.30%was achieved.Additionally,the carbon footprint analysis revealed that the process with energy integration had a low global warming potential(GWP)of-2.624 kg·kg^(-1)(CO_(2)/CaO).Conclusively,this work performed a systematic analysis of introducing biomass-derived H_(2)into CaCO_(3)calcination and demonstrated the positive role of reductive calcination using green H_(2)in mitigating CO_(2)emissions within the carbonate industry.

关键词： Biomass CaCO_(3)reductive calcination Chemical looping Hydrogen production Carbon footprint Thermodynamics process

In-situ powder mixing for laser-based directed energy deposition of functionally graded materials

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Advances in Manufacturing 2024年第1期12卷 150-166页

作者： ji-peng Chen Shou-Chun Xie He Huang School of Mechanical and Electronic Engineering Nanjing Forestry UniversityNanjing210037People’s Republic of China Nanjing Huirui Photoelectric Technology Co. LtdNanjing211121People’s Republic of China

The mixing of powders is a highly relevant field under additive manufacturing,however,it has attracted limited interest to date.The in-situ mixing of various powders remains a significant challenge.This paper proposes a new method utilizing a static mixer for the in-situ mixing of multiple powders through the laser-based directed energy deposition(DED)of functionally graded materials.Firstly,a powder-mixing experimental platform was established;WC and 316L powders were selected for the mixing experiments.Secondly,scanning electron microscopy,energy dispersive spectroscopy,and image processing were used to visually evaluate the homogeneity and proportion of the in-situ mixed powder.Furthermore,powder-mixing simulations were conducted to determine the powder-mixing mechanism.In the simulations,a powder carrier gas flow field and particle mixing were employed.Finally,a WC/316L metal matrix composite sample was produced using laser-based DED to verify the application potential of the static mixer.It was found that the static mixer could adjust the powder ratio online,and a response time of 1–2 s should be considered when adjusting the ratio of the mixed powder.A feasible approach for in-situ powder mixing for laser-based DED was demonstrated and investigated,creating the basis for functionally graded materials.

关键词： Laser Deposition Static mixer Powder mixing Functionally graded materials

In vivo imaging reveals a synchronized correlation among neurotransmitter dynamics during propofol and sevoflurane anesthesia

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Zoological Research 2024年第3期45卷 679-690页

作者： Gao-lin Qiu li-Jun peng peng Wang Zhi-Lai Yang ji-Qian Zhang Hu liu Xiao-Na Zhu jin Rao Xue-Sheng liu Department of Anesthesiology First Affiliated Hospital of Anhui Medical UniversityHefeiAnhui 230022China School of life Science and Technology ShanghaiTech UniversityShanghai 201210China

General anesthesia is widely applied in clinical practice.However,the precise mechanism of loss of consciousness induced by general anesthetics remains unknown.Here,we measured the dynamics of five neurotransmitters,includingγ-aminobutyric acid,glutamate,norepinephrine,acetylcholine,and dopamine,in the medial prefrontal cortex and primary visual cortex of C57BL/6 mice through in vivo fiber photometry and genetically encoded neurotransmitter sensors under anesthesia to reveal the mechanism of general anesthesia from a neurotransmitter perspective.Results revealed that the concentrations of γ-aminobutyric acid,glutamate,norepinephrine,and acetylcholine increased in the cortex during propofol-induced loss of consciousness.Dopamine levels did not change following the hypnotic dose of propofol but increased significantly following surgical doses of propofol anesthesia.Notably,the concentrations of the five neurotransmitters generally decreased during sevoflurane-induced loss of consciousness.Furthermore,the neurotransmitter dynamic networks were not synchronized in the non-anesthesia groups but were highly synchronized in the anesthetic groups.These findings suggest that neurotransmitter dynamic network synchronization may cause anesthetic-induced loss of consciousness.

关键词： General anesthesia Loss of consciousness In vivo neurotransmitter imaging Medial prefrontal cortex Primary visual cortex

Comparison of cytokine levels in prostatic secretion between the Ⅲa and Ⅲb subtypes of prostatitis

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Asian Journal of Andrology 2024年第1期26卷 77-84页

作者： Cheng-lin Han Yu-Xuan Deng peng Hu Bin-Tao Hu Tao Wang ji-Hong liu Ming-Chao li Department of Urology Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430000China

Chronic prostatitis/chronic pelvic pain syndrome(CP/CPPS),also known as National Institutes of Health(NIH)type Ⅲ prostatitis,is a common disorder with an unclear etiology and no known curative treatments.Based on the presence or absence of leukocytes in expressed prostatic secretion(EPS),CP/CPPS is classifiedfurther into Illa(inflammatory)and Illb(noninflammatory)subtypes.However,the severity of symptoms is not entirely consistent with the white blood cell(WBC)count.Following the preliminary finding of a link between inflammatory cytokines and CP/CPPS,we performed this clinical study with the aim of identifying cytokines that are differentially expressed according to whether the prostatitis subtype is Ⅲa or Ⅲb.We found that granulocyte colony-stimulating factor(G-CSF),interleukin-18(IL-18),and monocyte chemoattractant protein-1(MCP-1)levels were significantly elevated and interferon-inducible protein-10(IP-10)and platelet-derived growth factor-BB(PDGF-BB)levels were downregulated in the EPS of patients with type Ⅲa prostatitis.In a word,it is a meaningful study in which we investigate the levels of various cytokines in EPS according to whether prostatitis is the Ⅲa or Ⅲb subtype.The combination of G-CSF,IL-18,MCP-1,IP-10,and PDGF-BB expression levels could form a basis for classification,diagnosis,and therapeutic targets in clinical P/CPPS.

关键词： chronic prostatitis/chronic pelvic pain syndrome(CP/CPPS) cytokines NIH-Ⅲa NIH-ⅢB