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A class of natural pinus koraiensis population system with time delay and diffusion term

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International Journal of biomathematics 2024年第2期17卷 233-262页

作者： Guo-feng feng Jiaqi chen bin Ge School of Mathematical Sciences Harbin Engineering University Harbin 150001 P.R.China

In this paper,we consider the long-term sustainability of the northeast Korean *** propose a class of natural Korean pine population system with time delay and diffusion ***,by analyzing the roots distribution of the characteristic equation,we study the stability of the model system with diffusion terms and prove the occurrence of Hopf ***,we introduce lactation time delay into a population model with a diffusion term,based on stability theory of ordinary differential equation,norm form methods and center manifold theorem,the stability of bifurcating periodic solutions and the relevant formula for the direction of Hopf bifurcation are ***,some numerical simulations are given.

关键词： Pinus koraiensis populations delay diffusion term Hopf bifurcation periodic solution

Constant charge method or constant potential method:Which is better for molecular modeling of electrical double layers?

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Journal of Energy Chemistry 2024年第7期94卷 54-60页

作者： Liang Zeng Xi Tan Xiangyu Ji Shiqi Li Jinkai Zhang Jiaxing Peng Sheng bi Guang feng State Key Laboratory of Coal Combustion Schoolof Energy and PowerEngineeringHuazhong Universityof Science and Technology(HUST)Wuhan 430074HubeiChina Sorbonne Universite CNRSPhysico-chimie des Electrolytes et Nanosystemes InterfaciauxPHENIXF-75005 ParisFrance

In molecular modeling of electrical double layers(EDLs),the constant charge method(CCM)is prized for its computational efficiency but cannot maintain electrode equipotentiality like the more resourceintensive constant potential method(CPM),potentially leading to *** certain scenarios,CCM can yield results identical to ***,there are no clear guidelines to determine when CCM is sufficient and when CPM is ***,we conduct a series of molecular simulations across various electrodes and electrolytes to present a comprehensive comparison between CCM and CPM under different charging *** reveal that CCM approximates CPM effectively in capturing equilibrium EDL and current-driven dynamics in open electrode systems featuring ionic liquids or regular concentration aqueous electrolytes,while CPM is indispensable in scenarios involving organic and highly concentrated aqueous electrolytes,nanoconfinement effects,and voltage-driven *** work helps to select appropriate methods for modeling EDL systems,prioritizing accuracy while considering computationalefficiency.

关键词： Electrochemical interface Molecular dynamics Electrode polarization modeling Nanoconfinement effect

A Random Fusion of Mix 3D and Polar Mix to Improve Semantic Segmentation Performance in 3D Lidar Point Cloud

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 845-862页

作者： Bo Liu Li feng Yufeng chen School of Computer Science and Engineering Macao University of Science and TechnologyMacao999078China School of Computer Science and Artificial Intelligence Chaohu UniversityChaohu238000China Institute of Vehicle Information Control and Network Technology Hubei University of Automotive TechnologyShiyan442002China

This paper focuses on the effective utilization of data augmentation techniques for 3Dlidar point clouds to enhance the performance of neural network *** point clouds,which represent spatial information through a collection of 3D coordinates,have found wide-ranging *** augmentation has emerged as a potent solution to the challenges posed by limited labeled data and the need to enhance model generalization *** of the existing research is devoted to crafting novel data augmentation methods specifically for 3D lidar point ***,there has been a lack of focus on making the most of the numerous existing augmentation *** this deficiency,this research investigates the possibility of combining two fundamental data augmentation *** paper introduces PolarMix andMix3D,two commonly employed augmentation techniques,and presents a new approach,named *** of using a fixed or predetermined combination of augmentation methods,RandomFusion randomly chooses one method from a pool of options for each instance or *** innovative data augmentation technique randomly augments each point in the point cloud with either PolarMix or *** crux of this strategy is the random choice between PolarMix and Mix3Dfor the augmentation of each point within the point cloud data *** results of the experiments conducted validate the efficacy of the RandomFusion strategy in enhancing the performance of neural network models for 3D lidar point cloud semantic segmentation *** is achieved without compromising computational *** examining the potential of merging different augmentation techniques,the research contributes significantly to a more comprehensive understanding of how to utilize existing augmentation methods for 3D lidar point *** data augmentation technique offers a simple yet effective method to leverage the diversity of augmentation techniques and boost the ro

关键词： 3D lidar point cloud data augmentation RandomFusion semantic segmentation

Reviewing electrochemical stability of ionic liquids-/deep eutectic solvents-based electrolytes in lithium-ion,lithium-metal and post-lithium-ion batteries for green and safe energy

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Green Energy & Environment 2024年第6期9卷 966-991页

作者： Yu chen Shuzi Liu Zixin bi Zheng Li fengyi Zhou Ruifen Shi Tiancheng Mu Department of Chemistry and Material Science Langfang Normal UniversityNO.100 Aimin West RoadLangfangHebei065000China Department of Chemistry Renmin University of ChinNO.59 Zhongguancun StreetHaidian DistrictBeijing100872China

Sustainable energy is the key issue for the environment protection,human activity and economic *** liquids(ILs)and deep eutectic solvents(DESs)are dogmatically regarded as green and sustainable electrolytes in lithium-ion,lithium-metal(e.g.,lithium-sulphur,lithium-oxygen)and post-lithium-ion(e.g.,sodium-ion,magnesium-ion,and aluminum-ion)*** electrochemical stability of ILs/DESs is one of the prerequisites for green,sustainable and safe energy;while easy electrochemical decomposition of ILs/DESs would be contradictory to the concept of green chemistry by adding the cost,releasing volatile/hazardous by-products and hindering the ***,(1)are ILs/DESs-based electrolytes really electrochemically stable when they are not used in batteries?(2)are ILs/DESs-based electrolytes really electrochemically stable in real batteries?(3)how to design ILs/DESs-based electrolytes with high electrochemical stability for batteries to achieve sustainability and green development?Up to now,there is no summary on this topic,to the best of our ***,we review the effect of chemical structure and non-structural factors on the electrochemical stability of ILs/DESs in simulated *** importantly,electrochemical stability of ILs/DESs in real lithium-ion,lithium-metal and post-lithium-ion batteries is concluded and ***,the strategies to improve the electrochemical stability of ILs/DESs in lithium-ion,lithium-metal and post-lithium-ion batteries are *** review would provide a guide to design ILs/DESs with high electrochemical stability for lithium-ion,lithium-metal and postlithium-ion batteries to achieve sustainable and green energy.

关键词： Green solvents Decomposition Sustainable chemistry Lithium-oxygen batteries Lithium-sulphur batteries Sodium-ion batteries

Enhancing the mechanical properties of casting eutectic high -entropy alloys via W addition

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1364-1372页

作者： Xu Yang Dezhi chen Li feng Gang Qin Shiping Wu Ruirun chen National Key Laboratory for Precision Hot Processing of Metals School of Material Science and EngineeringHarbin Institute of TechnologyHarbin 150001China

The effect of W element on the microstructure evolution and mechanical properties of Al_(1.25)CoCrFeNi3 eutectic high-entropy alloy and Al_(1.25)CoCrFeNi_(3-x)W_(x)(x=0,0.05,0.1,0.3,and 0.5;atomic ratio)high-entropy alloys(HEAs)were *** show that the Al_(1.25)CoCrFeNi_(3-x)W_(x) HEAs are composed of face-centered cubic and body-centered cubic(BCC)*** W content increases,the microstructure changes from eutectic to *** addition of W lowers the nucleation barrier of the BCC phase,decreases the valence electron concentration of the HEAs,and replaces Al in the BCC phase,thus facilitating the nucleation of the BCC *** results show that the addition of W greatly improves the mechanical properties,and solid-solution,heterogeneous-interface,and second-phase strengthening are the main strengthening *** yield strength,tensile strength,and elongation of the Al_(1.25)CoCrFeNi2.95W0.05 HEA are 601.44 MPa,1132.26 MPa,and 15.94%,respectively,realizing a balance between strength and *** fracture mode of the Al_(1.25)CoCrFeNi_(3-x)W_(x) HEAs is ductile–brittle mixed fracture,and the crack propagates and initiates in the BCC *** eutectic lamellar structure impedes crack propagation and maintains plasticity.

关键词： high-entropy alloy microstructure mechanical property fracture behavior

Energy and exergy analyses and optimizations for two-stage TEC driven by two-stage TEG with Thomson effect

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Science China(Technological Sciences) 2024年第4期67卷 1077-1093页

作者： chen LinGen GE YanLin feng HuiJun REN TingTing Institute of Thermal Science and Power Engineering Wuhan Institute of TechnologyWuhan 430205China Hubei Provincial Engineering Technology Research Center of Green Chemical Equipment Wuhan 430205China School of Mechanical&Electrical Engineering Wuhan Institute of TechnologyWuhan 430205China

Based on the non-equilibrium thermodynamics and energy and exergy analyses,a thermodynamic model of two-stage thermoelectric(TE)cooler(TTEC)driven by two-stage TE generator(TTEG)(TTEG-TTEC)combined TE device is established with involving Thomson effect by fitting method of variable physical parameters of TE *** total number of TE elements as constraint,influences of number distributions of TE elements on three device performance indictors,that is,cooling load,maximum COP and maximum exergetic efficiency,are *** number distributions of TE elements are optimized with three maximum performance indictors as the objectives,*** of hot-junction temperature of TTEG and coldjunction temperature of TTEC on optimization results are analyzed,and difference between optimization results corresponding to three performance indicators are *** performance intervals and optimal variable intervals are *** of Thomson effect on three general performance indicators,three optimal performance indicators and optimal variables are comparatively *** effect reduces three general performance indicators and three optimal performance indicators of *** hot-and cold-junction temperatures of TTEG and TTEC are 450,305,325 and 295 K,respectively,Thomson effect reduced maximum cooling load,maximum COP and maximum exergetic efficiency from 9.528 W,9.043×10^(-2)and2.552%to 6.651 W,6.286×10^(-2)and 1.752%,respectively.

关键词： non-equilibrium thermodynamics cooling load COP exergetic efficiency combined thermoelectric device performance optimization

Constructal design of a rectangular porous fin considering minimization of maximum temperature difference and pumping power consumption

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Science China(Technological Sciences) 2024年第3期67卷 919-929页

作者： LIU XiaoYe feng HuiJun chen LinGen GE YanLin Institute of Thermal Science and Power Engineering Wuhan Institute of TechnologyWuhan 430205China College of Power Engineering Naval University of EngineeringWuhan 430033China Hubei Provincial Engineering Technology Research Center of Green Chemical Equipment Wuhan 430205China School of Mechanical&Electrical Engineering Wuhan Institute of TechnologyWuhan 430205China

A heat dissipation model of a rectangular porous fin is established based on constructal theory. First, the constructal design of rectangular porous fin is conducted by selecting a complex function minimization, which composed of linear weighting sum of maximum temperature difference and pumping power consumption, as optimization objective. Effects of gap height, air inlet velocity, total porous fin volume and porosity on the optimal constructs are investigated, respectively. The findings show that the complex function can attain its double minimum at a value of 0.802 when the fin length and number are optimized, and the corresponding optimal fin length and number are 8.01 mm and 10, respectively. In comparison to original design, the complex function and maximum temperature difference after twice optimization are decreased by 19.80% and 66.31%, ***, the comprehensive performance of porous fin is improved by simultaneously optimizing the fin length and number. The artificial neural network is applied to predict the fin performances, which is used to conduct multi-objective optimization based on NSGA-II algorithm. Optimal structure of porous fin for multiple requirements is gained by LINMAP and TOPSIS decisionmaking strategies. The findings in this study can serve as theoretical guides for fin thermal designs of electronic devices.

关键词： constructal theory rectangular porous fin pumping power consumption maximum temperature difference complex function multi-objective optimization

Differences in Toxicokinetics and Maternal Transfer between Lipophilic and Proteinophilic Halogenated Organic Pollutants in Laying Hens

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Environment & Health 2024年第10期2卷 712-720页

作者： Xiao-Jun Luo Qun-Jie feng Chu-Hong Zhu Xi chen Peng-Peng chen Yan-Hong Zeng bi-Xian Mai State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection and Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640P.R.China State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640P.R.China University of Chinese Academy of Sciences Beijing 100049P.R.China

In this study,we conducted exposure experiments on egg-laying hens to explore the toxicokinetics and maternal transfer characteristics of lipophilic and proteinophilic halogenated organic pollutants(HOPs).The lipophilic HOPs included polychlorinated biphenyls(PCBs),polybrominated diphenyl ethers(PBDEs),and dechlorane plus(DPs),while the proteinophilic HOPs included perfluorocarboxylic acids(PFCAs).The results revealed that most of lipophilic HOPs exhibit lower depuration rate(kd)than *** kd of lipophilic HOPs correlated with the octanol−water partition coefficient(log KOW)values in a V-shaped curve,whereas that of PFCAs correlated with the protein−water partition coefficient(log KPW)values in an inverted V-shaped *** depuration rate,rather than the uptake rate,was a leading factor in determining the bioaccumulation potential of HOPs in *** the dominant factors determining the tissue distribution of the two types of compounds were explicit(fats vs phospholipids),chemical-specific tissue distribution was still *** egg-maternal concentration ratio was dependent on the exposure status,concentration,and maternal tissue *** a single maternal tissue may not be an appropriate method for assessing chemical maternal transfer *** have a greater maternal transfer potential(>80%of the total body burden)than lipophilic HOPs(approximately 30%for BDE209 and DPs,and less than 10%for the others).Their lipophilic and partly proteinophilic nature makes the toxicokinetics and maternal transfer characteristics of BDE209 and DPs different from those of other lipophilic *** findings are crucial for enhancing our understanding of the behavior and fate of HOPs in egg-laying hens.

关键词： halogenated organic pollutants laying hens toxicokinetic maternal transfer

Polyvinyl alcohol fiber cement-stabilized macadam:A review and performance evaluation

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第3期11卷 406-423页

作者： Chaohui Wang Jikang Liu Shaochang chen feng chen Zhiwei Gao School of Highway Chang'an UniversityXi'an 710064China Shaanxi Transportation Technology Consulting Co. Ltd.Xi'an 710068China School of Information Engineering Xizang Minzu UniversityXianyang 712082China

This review evaluated research results on polyvinyl alcohol fiber cement-stabilized macadam(PVA-FCSM)to further improve the long-term durability of road structures and promote its in-depth study and high-quality *** suitable PVA fiber technical indexes for ordinary cement-stabilized macadam(CSM)were *** difference in the mechanical properties between CSM and PVA-FCSM was *** extent to which PVA fibers enhance the durability of CSM were ***,the mechanism of enhancement of CSM by PVA fibers was ***,the performance of each type of fiber cement-stabilized macadam(FCSM)was compared and *** results indicated that the suggested PVA fiber length and content for CSM were 12-30 mm and 0.6-1.2 kg/m^(3),*** different ages,the mean degree of improvement in the unconfined compressive strength was 14%,20%,and 14%,that in the compressive resilience modulus was 8%,11%,and 6%,and that in the splitting strength was 29%,15%,and 22%,*** different ages,the mean degree of decreased in the dry shrinkage coefficient was 21%,16%,and 15%and that in the temperature shrinkage coefficient(20℃-30℃)was 23%,23%,and 18%,*** coefficients increased with extended curing ***,at the same stress level,PVA-FCSM has a higher fatigue life compared to *** bridging effect,high strength,and high modulus of PVA fiber enhance the strength and anti-cracking of *** recommended fiber type for CSM is PVA fiber.

关键词： Highway and railway engineering PVA fiber cement-stabilized macadam Mechanical performance Durability Enhancement mechanism Performance valuation