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Hot Deformation Behavior and Microstructures Evolution of GNP-Reinforced Fine-Grained Mg Composites

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Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 407-424页

作者： Hengrui Hu Jiayu qin Yunpeng Zhu Jinhui Wang Xiaoqiang li Peipeng Jin qinghai Provincial Key Laboratory of New light Alloys Qinghai UniversityXining 810016China qinghai Provincial Engineering Research Center of High Performance light Metal Alloys and Forming Qinghai UniversityXining 810016China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China School of Material Science and Engineering Lanzhou University of TechnologyLanzhou 730050China

Graphene nanoplates(GNPs)-reinforced magnesium matrix composites have been attracted great ***,knowledge is lack for the hot deformation behavior of GNP-reinforced magnesium(GNPs/Mg)*** this study,the fine-grained GNPs/Mg composite was fabricated by powder metallurgy process followed by *** hot deformation behavior,microstructure evolution and dynamic recrystallization(DRX)mechanism of fine-grained GNPs/Mg composite were investigated by hot compression test and electron back-scatter diffraction(EBSD).The hot compression tests of the composite were conducted at temperatures between 423 and 573 K with the strain rates from 0.001 to 1 s^(-1).The strain compensated power law equation was established to describe the hot deformation behavior of the *** stress exponent and activation energy of the composite are 7.76 and 83.23 kJ/mol,respectively,suggesting that the deformation mechanism is grain boundary slip controlled dislocation climb *** abnormally high stress exponent and activation energy are unattainable in the composite due to the fine grain size of the composites and the absence of Zener pinning and Orowan effects of GNPs *** grain size increases with the decrease in Zener-Hollomn(Z)parameter,which can be well fitted by power-law *** the increase in grain size and decrease in Z parameter,the geometrically necessary dislocation density decreases,which shows the approximately power-law relationship.A random and weak texture was formed after hot *** discontinuous dynamic recrystallization and continuous dynamic recrystallization mechanism dominated the DRX behavior at 473 K/0.001 s^(-1) and 573 K/0.001 s^(-1),respectively.

关键词： GNPs Mg composite Hot deformation behavior Constitutive equations Microstructure evolution Dynamic recrystallization

Evaluation of the intracellular lipid-lowering effect of polyphenols extract from highland barley in HepG2 cells

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Food Science and Human Wellness 2024年第1期13卷 454-461页

作者： Yijun Yao Zhifang li Bowen qin Xingrong Ju lifeng Wang College of Food Science and Engineering/Collaborative Innovation Centre for Modern Grain Circulation and Safety Nanjing University of Finance and EconomicsNanjing 210023China

Active ingredients from highland barley have received considerable attention as natural products for developing treatments and dietary supplements against *** practical application,the research of food combinations is more significant than a specific food *** study investigated the lipid-lowering effect of highland barley polyphenols via lipase assay in vitro and HepG2 cells induced by oleic acid(OA).Five indexes,triglyceride(TG),total cholesterol(T-CHO),low density lipoprotein-cholesterol(LDL-C),aspartate aminotransferase(AST),and alanine aminotransferase(ALT),were used to evaluate the lipidlowering effect of highland barley *** also preliminary studied the lipid-lowering mechanism by Realtime fluorescent quantitative polymerase chain reaction(q PCR).The results indicated that highland barley extract contains many components with lipid-lowering effects,such as hyperoside and *** vitro,the lipase assay showed an 18.4%lipase inhibition rate when the additive contents of highland barley extract were 100μg/m *** intracellular lipid-lowering effect of highland barley extract was examined using 0.25 mmol/L OA-induced HepG2 *** results showed that intracellular TG,LDL-C,and T-CHO content decreased by 34.4%,51.2%,and 18.4%,*** and AST decreased by 51.6%and 20.7%compared with the untreated hyperlipidemic HepG2 cells.q PCR results showed that highland barley polyphenols could up-regulation the expression of lipid metabolism-related genes such as PPARγand Fabp4.

关键词： Highland barley Polyphenols extract lipid-lowering effect HepG2 cells

A REDUCED ORDER SCHWARZ METHOD FOR NONliNEAR MULTISCALE ELliPTIC EQUATIONS BASED ON TWO-LAYER NEURAL NETWORKS

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Journal of Computational Mathematics 2024年第2期42卷 570-596页

作者： Shi Chen Zhiyan Ding qin li Stephen J.Wright Mathematics Department University of Wisconsin-MadisonMadisonWI 53706USA Department of Mathematics University of California-BerkeleyBerkeley CA 94720USA Mathematics Department and Discovery Institute University of Wisconsin-Madison MadisonWI 53706USA Computer Sciences Department University of WisconsinMadisonWI 53706USA

Neural networks are powerful tools for approximating high dimensional data that have been used in many contexts,including solution of partial differential equations(PDEs).We describe a solver for multiscale fully nonlinear elliptic equations that makes use of domain decomposition,an accelerated Schwarz framework,and two-layer neural networks to approximate the boundary-to-boundarymap for the subdomains,which is the key step in the Schwarz ***,the boundary-to-boundary map requires solution of boundary-value elliptic problems on each *** leveraging the compressibility of multiscale problems,our approach trains the neural network offline to serve as a surrogate for the usual implementation of the boundary-to-boundary *** method is applied to a multiscale semilinear elliptic equation and a multiscale p-Laplace *** both cases we demonstrate significant improvement in efficiency as well as good accuracy and generalization performance.

关键词： Nonlinear homogenization Multiscale elliptic problem Neural networks Do-main decomposition

Natural variation of an autophagy-family gene among rice subspecies affects grain size and weight

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The Crop Journal 2024年第1期12卷 121-132页

作者： Shiying Huang Peng Wang Caijing li qingwen Zhou Tao Huang Yicong Cai qin Cheng hui Wang Qi Zhong Zhihao Chen liping Chen Haohua He Jianmin Bian Key Laboratory of Crop Physiology Ecology and Genetic BreedingMinistry of Education.Jiangxi Agricultural UniversityNanchang 330045JiangxiChina Weill Cornell Medical Immunology and Microbiology1300 York AvenueBox 62New YorkNY 10065USA

Elucidating the genetic basis of natural variation in grain size and weight among rice varieties can help breeders develop high-yielding *** identified a novel gene,GW3a(Grain Weight 3a)(LOC_Os03g27350),that affects rice grain size and ***3a mutants showed higher total starch content and dry matter accumulation than the wild type(WT),Nipponbare,suggesting that GW3a negatively regulates grain size and ***,our study found that GW3a interacted with OsATG8 by cleaving it,suggesting that GW3a may be involved in the assembly of autophagosomes and starch degradation in *** haplotype analysis of GW3a showed functional differences between indica and japonica *** together,we conclude that GW3a is expressed in the autophagosome pathway regulating starch metabolism in rice,affecting yield-related traits,such as grain size,grain weight and thousand grain weight(TGW).Our findings also shed new light on autophagy-mediated yield trait regulation,proposing a possible strategy for the genetic improvement of high-yield germplasm in rice.

关键词： Grain size GW3a Autophagy Starch content

A ratiometric optical thermometer with dual-color emission based on Eu^(2+)-doped CsCu_(2)I_(3) microcrystals

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Journal of Rare Earths 2024年第8期42卷 1429-1436,I0001页

作者： Xiaorong li Ge Gao Kaiyu Wang Zhaoqiong Chen Zejiang Gao qingyong qin li Chen Bingsuo Zou State Key Laboratory of Featured Metal Materials and life-cycle Safety for Composite Structures School of Physical Science and TechnologyGuangxi UniversityNanning530004China School of Resources Environments and MaterialsGuangxi UniversityNanning530004China

With the increasing demand for non-co ntact fluorescence intensity ratio-based optical thermometry,novel phosphor materials with high-efficiency,dual-emitting centers,and differentiable temperature sensitivity are highly desired,In this wo rk,rare earth Eu^(2+) ions were incorporated Wnto CsCu_(2)I_(3) microcrystals by solidstate reaction,Under a single UV excitation,the as-synthesized samples exhibit two emissions:452 nm blue emission from the 5d→4f transition of Eu^(2+)and 582 nm yellow emission from self-trapped exciton e mission of CsCu_(2)I_(3).The photoluminescence quantum yield reaches to 50%,The dual-band emission of Eu^(2+)-doped CsCu_(2)I_(3) shows different temperature responses in the range of 260-360 *** on fluorescence intensity ratio technology,the maximum absolute sensitivity and re Iative sensitivity are 0.091 K^(-1)(at 360 K) and 2.60%/K(at 260 K),*** results suggest that Eu^(2+)-doped GsCu_(2)I_(3) could be a good candidate for highly sensitive optical thermometer.

关键词： CsCu_(2)I_(3) Eu^(2+)-doping Fluorescence intensity ratio Optical thermometer Rare earths

Maximum initial primary wave model for low-Froude-number reservoir landslides based on wave theory

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Journal of Mountain Science 2024年第8期21卷 2664-2680页

作者： li Yang HUANG Bolin qin Zhen DONG Xingchen HU Lei National Field Observation and Research Station of Landslides in Three Gorges Reservoir Area of Yangtze River Yichang 443002China College of Civil Engineering&Architecture China Three Gorges UniversityYichang 443002China

The impulse waves induced by large-reservoir landslides can be characterized by a low Froude ***,systematic research on predictive models specifically targeting the initial primary wave is *** the Shuipingzi 1#landslide that occurred in the Baihetan Reservoir area of the Jinsha River in China as an engineering example,this study established a large-scale physical model(with dimensions of 30 m×29 m×3.5 m at a scale of 1:150)and conducted scaled experiments on 3D landslide-induced impulse *** the process in which a sliding mass displaced and compressed a body of water to generate waves,the maximum initial wave amplitude was found to be positively correlated with the sliding velocity and the volume of the *** the increase in the water depth,the wave amplitude initially increased and then *** duration of pressure exertion by the sliding mass at its maximum velocity directly correlated with an elevated wave *** on the theories of low-amplitude waves and energy conservation,while considering the energy conversion efficiency,a predictive model for the initial wave amplitude was *** model could fit and validate the functions of wavelength and wave *** accuracy of the initial wave amplitude was verified using physical experiment data,with a prediction accuracy for the maximum initial wave amplitude reaching 90%.The conversion efficiency(η)directly determined the accuracy of the estimation *** clear conditions for landslide-induced impulse wave generation,estimating the value ofηthrough analogy cases was *** study has derived the landslide-induced impulse waves amplitude prediction formula from the standpoints of wave theory and energy conservation,with greater consideration given to the intrinsic characteristics in the formation process of landslide-induced impulse waves,thereby enhancing the applicability and extensibility of the *** can facilitate the development

关键词： Three-dimensional physical model experiments Reservoir-landslide-induced impulse wave Energy conversion efficiency Landslide-induced impulse wave prediction model Shuipingzi 1#landslide

Performance Enhancement of Parabolic Trough Collector by Using Homogenizer and Spiral

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Journal of Thermal Science 2024年第2期33卷 658-674页

作者： li Peijing liU Taixiu qin Yuanlong ZHENG Zhimei ZHAO Kai liU Qibin School of Energy Powerand Mechanical EngineeringNorth China Electric Power UniversityBeijing102206China Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing100190China University of Chinese Academy of Science Beijing100049China Department of Thermal Science and Energy Engineering University of Science and Technology of ChinaHefei230027China Research Institute of Science and Technology of China Three Gorges Group Corporation Beijing100038China

In conventional parabolic trough collectors(PTCs),sunlight is concentrated at the bottom of the absorber tube,resulting in a significant circumferential temperature gradient across the absorber tube,heat loss and thermal deformation,which affects the safety and thermal performance of *** this study,a new receiver with homogenizer and spiral(RHS) is proposed,achieving the optical and thermal synergy to ameliorate the thermal deformation of the absorber tube and enhance thermal efficiency.A plane structure homogenizer is designed to improve uniformity of the concentrated solar flux of absorber tube through second *** combination with the spiral,it improves the optical-thermal efficiency of the PTC by enhancing heat exchange between the fluid and the backlight side of the absorber *** performance of the collector is numerically studied by building a three-dimensional coupled light-thermal-structure *** results show that the thermal deformation of the RHS is reduced by more than 96% and the optical-thermal efficiency is improved by 1.2%-0.63% compared with conventional receivers(CRs) under the same inlet temperature *** proposed receiver is validated to be effective in reducing thermal deformation and improving optical-thermal efficiency.

关键词： parabolic trough collector homogenizer thermal deformation spiral

Reheat effect on the improvement in efficiency of the turbine driven by pulse detonation

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Defence Technology（防务技术） 2024年第1期31卷 200-210页

作者： Junyu liu Zhiwu Wang Zixu Zhang Junlin li Weifeng qin Jingjing Huang School of Power and Energy Northwestern Polytechnical UniversityXi’an 710072China Shenzhen Research Institute of Northwestern Polytechnical University Shenzhen 518057China Mechanical Engineering College Xi’an Shiyou UniversityXi’an 710065China

Due to the strong unsteadiness of pulse detonation,large flow losses are generated when the detonation wave interacts with the turbine blades,resulting in low turbine *** that the flow losses are dissipated into the gas as heat energy,some of them can be recycled during the expansion process in subsequent stages by the reheat effect,which should be helpful to improve the detonationdriven turbine *** this into account,this paper developed a numerical model of the detonation chamber coupled with a two-stage axial turbine,and a stoichiometric hydrogen-air mixture was *** improvement in turbine efficiency attributable to the reheat effect was calculated by comparing the average efficiency of the stages with the efficiency of the two-stage *** research indicated that the first stage was critical in suppressing the flow unsteadiness caused by pulse detonation,which stabilized the intake condition of the second stage and consequently allowed much of the flow losses from the first stage to be recycled,so that the efficiency of the two-stage turbine was *** a 95%confidence level,the efficiency improvement was stable at 4.5%—5.3%,demonstrating that the reheat effect is significant in improving the efficiency of the detonation-driven turbine.

关键词： Pulse detonation turbine engine Hydrogen detonation Turbine efficiency Reheat effect Multi-cycle detonation

Synthesis of highly stable Ni nanoparticles via electrostatic self-assembly for enhanced hydrogen storage of MgH2

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Rare Metals 2024年第9期43卷 4356-4366页

作者： qin-Ke Tang Jiang-Chuan liu Rui Shi Yun-Feng Zhu Ji-Guang Zhang Ya-Na liu Jun Wang Yao Zhang Xiao-hui Hu Zhi-Bin liu li-Quan li College of Materials Science and Engineering Jiangsu Collaborative Innovation Centre for Advanced Inorganic Function CompositesNanjing Tech University School of Materials Science and Engineering Southeast University

Magnesium-based hydrides have been widely recognized as an appropriate choice for solid-state hydrogen ***,its undesirable thermodynamics and sluggish hydrogenation/dehydrogenation kinetics are major bottlenecks for its ***,a highly stable and highly dispersed Ni-based catalyst （Ni/Al2O3/GN） was fabricated to promote the hydrogen storage performance of MgH2via the electrostatic effect of NiAl-LDH/GN precursor with a co-calcination reduction ***2-5wt % Ni/Al2O3/GN exhibits excellent hydrogen storage performance,releasing about 5.7 wt % hydrogen in 3500 s at 250℃,and can reach a saturation hydrogen absorption of about 6.15 wt% in 3000 s at 100℃.Furthermore,it also shows low dehydrogenation apparent activation energy of 89.1 and 118.2 kJ·***,the catalyst ensures the stability of both the physical phase and structure during ball milling and cycling *** role of each phase in Ni/Al2O3/GN on the hydrogen storage performance of MgH2was also discussed through experiments and theoretical calculation,and the synergistic catalytic mechanism of Ni/Al2O3/GN was clearly *** work provides a unique perspective for the preparation of highly stable and highly dispersible catalysts.

关键词： Catalytic mechanism Hydrogen storage performance Magnesium hydride Ni/Al2O3/GN