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The asymptotic behavior and ergodicity of stochastically perturbed SVIR epidemic model

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International Journal of Biomathematics 2016年第3期9卷 177-190页

作者： yanan zhao Daqing Jiang School of Mathematics and Statistics Northeast Normal University Changchun 130024 Jilin P. R. China School of Science Changchun University Changchun 130022 Jilin P. R. China Nonlinear Analysis and Applied Mathematics (NAAM) Research Group King Abdulaziz University Jeddah Saudi Arabia College of Science China University of Petroleum (East China) Qingdao 266580 P. R. China

In this paper, we introduce stochasticity into an SIR epidemic model with vaccina- tion. The stochasticity in the model is a standard technique in stochastic population modeling. When the perturbations are small, by the method of stochastic Lyapunov functions, we carry out a detailed analysis on the dynamical behavior of the stochastic model regarding of the basic reproduction number R0. If R0 ≤ 1, the solution of the model is oscillating around a steady state, which is the disease-free equilibrium of the corresponding deterministic model. If R0 〉 1, there is a stationary distribution and the solution has the ergodic property, which means that the disease will prevail.

关键词： Stochastic SVIR epidemic model disease-free equilibrium stationary distri-bution ergodicity stochastic Lyapunov functions.

Facile SERS screening of melamine in bovine milk with 2D printed AgNPs/glass fabric filter paper as the flexible substrate

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Food Science and Human Wellness 2024年第5期13卷 2595-2600页

作者： Shiyao Wang yanan zhao Xiao Wei Yisheng Chen College of Food Science and Engineering Shanxi Agricultural UniversityTaigu 030801China Food Nutrition and Safety Institute Shanxi Agricultural UniversityTaiyuan 030031China School of Food Science and Technology Jiangnan UniversityWuxi 214122China

Melamine is one of the most frequently detected adulterants in dairy *** current study proposes a surface-enhanced Raman spectroscopy(SERS)-based analytical tool for fast and reliable screening of melamine in bovine milk.A hand-held Raman spectrometer was used in conjunction with a substrate composed of silver nanoparticles(AgNPs)that was 2D printed onto glass fiber(GF)filter *** optimized conditions,a sensitive and fingerprint-like signal at 674 cm^(-1) was *** AgNPs/GF substrate exhibited high sensitivity to melamine in milk down to 1.9498×10^(-5)mg/mL,which is well below the USA and EU safety limits(2.5×10^(-3)mg/mL).Remarkably,the proposed technology was also highly reproducible,showing spot-to-spot and block-to-block variations below 3.3%and 4.9%at 674 cm^(-1) in Raman intensity,*** characteristic peak intensity and concentration of melamine showed an acceptable linear relationship(R^(2)=0.9909)within the range of 0.0001-1 mg/***,the method established in this study can provide an efficient and effective method for the quantitative target screening and detection of melamine in dairy products.

关键词： 2D print Melamine Milk Surface-enhanced Raman spectroscopy(SERS) flexible substrate

Bi-objective Layout Optimization for Multiple Wind Farms Considering Sequential Fluctuation of Wind Power Using Uniform Design

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CSEE Journal of Power and Energy Systems 2022年第6期8卷 1623-1635页

作者： Yinghao Ma Kaigui Xie yanan zhao Hejun Yang Dabo Zhang Anhui Province Key Laboratory of Renewable Energy Utilization and Energy Saving Hefei University of TechnologyHefei 230009China State Key Laboratory of Power Transmission Equipment&System Security and New Technology Chongqing UniversityChongqing 400044China School of Computer Science and Technology at University of Science and Technology of China Hefei 230027China

The fluctuation of wind power brings great challenges to the secure,stable,and cost-efficient operation of the power *** of the time-correlation of wind speed and the wake effect of wind turbines,the layout of wind farm has a significant impact on the wind power sequential *** order to reduce the fluctuation of wind power and improve the operation security with lower operating cost,a bi-objective layout optimization model for multiple wind farms considering the sequential fluctuation of wind power is proposed in this *** goal is to determine the optimal installed capacity of wind farms and the location of wind *** proposed model maximizes the energy production and minimizes the fluctuation of wind power *** improve the accuracy of wind speed estimation and hence the power calculation,the timeshifting of wind speed between the wind tower and turbines’locations is also considered.A uniform design based two-stage genetic algorithm is developed for the solution of the proposed *** studies demonstrate the effectiveness of this proposed model.

关键词： Wind farm layout optimization(WFLO) wind power fluctuation bi-objective optimization uniform design

The simultaneous improvements of strength and ductility in additive manufactured Ni-based superalloy via controlling cellular subgrain microstructure

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Journal of Materials Science & Technology 2021年第9期68卷 184-190页

作者： yanan zhao Zongqing Ma Liming Yu Ji Dong Yongchang Liu State Key Lab of Hydraulic Engineering Simulation and Safety.School of Materials Science and Engineering Tianjin UniversityTianjin 300072China Tianjin Sino-German University of Applied Sciences TianjinChina

Fine cellular subgrain structure was formed in the Selective Laser Melting(SLM) manu factured IN718 alloy via optimizing the processing *** the subsequent homogenization heat treatment process,the Laves phase dispersed at the subgrain boundaries can be eliminated while the cellular subgrain structure is reserved in the printed samples after holding at 1080℃ for 50 *** the prolongation of the holding time,the subgrain boundaries undergo low angle rotation via the motion ofdislocation,which leads to the annihilation of the cellular subgrain ***,during the subsequent double aging heat treatment process,the reserved cellular subgrain structure in the homogenized samples promotes the precipitation of γ" second phase nanoparticles,and these precipitated γ" phase nanoparticles prefer to distribute at subgrain *** was found that these unique subgrain boundaries with γ" phase precipitates can hinder but not fully terminate the motion of dislocation during the plastic deformation process,which contributes to increasing the strength as well as holding the stable plastic ***,the strength and ductility of final prepared IN718 alloy with cellular subgrain microstructure were improved simultaneously compared to the prepared alloy without cellular subgrain structure,which even exceed the mechanical properties standards(AMS 5662) of wrought IN718 *** results in our work suggest that controlling the subgrain structure is a promising effective strategy to improve the mechanical properties of SLM manu factured nickel-based superalloy.

关键词： Selective laser melting Superalloy Subgrain structure Strengthening and toughening

Enhancing the electric fields around the nanorods by using metal grooves

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Science China(Physics,Mechanics & Astronomy) 2012年第10期55卷 1763-1768页

作者： zhao yanan QIN Yan CAO Wei ZHANG ZhongYue College of Physics and Information Technology Shaanxi Normal UniversityXi'an 710062China School of Physical Science and Technology Southwest UniversityChongqing 400715China

To enhance electric fields around nanorods,a Ag nanorod-groove system is presented and its electric field distribution is studied using the finite difference time domain *** the superposition of the electric fields of the split multi-beam of light works as excitation for electron oscillations in the nanorods,enhanced electric fields occur around the *** addition,the effects of topological parameters of the nanorod-groove system,such as the oblique angle of the groove,displacement of the nanorod to the bottom of the groove,and separation between the nanorods on electric field distributions are also *** results may be helpful for designing substrates to obtain larger electric fields around nanorods.

关键词： optical property nanorod-groove system plasmon finite difference time domain method

Iron oxide nanoparticles with photothermal performance and enhanced nanozyme activity for bacteria-infected wound therapy

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Regenerative Biomaterials 2022年第1期9卷 548-559页

作者： Jiaxin Guo Wenying Wei yanan zhao Honglian Dai State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Biomedical Materials and Engineering Research Center of Hubei ProvinceWuhan University of TechnologyWuhan 430070China Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory Xianhu Hydrogen ValleyFoshan 528200China Shenzhen Research Institute of Wuhan University of Technology Shenzhen 518000China

Metal-based nanomaterials usually have broad-spectrum antibacterial properties,low biological toxicity and no drug resistance due to their intrinsic enzyme-like catalytic properties and external field(magnetic,thermal,acoustic,optical and electrical)***,iron oxide(Fe_(3)O_(4))nanoparticles(IONPs)synthesized by us have good biosafety,excellent photothermal conversion ability and peroxidase-like catalytic activity,which can be used to construct a photothermal-enzymes combined antibacterial treatment *** with peroxide-like catalytic activity can induce H_(2)O_(2)to catalyze the production of·OH in a slightly acidic environment,thus achieving certain bactericidal effects and increasing the sensitivity of bacteria to *** stimulated by near-infrared light,the photothermal effect could destroy bacterial cell membranes,resulting in cleavage and inactivation of bacterial protein,DNA or ***,it can also improve the catalytic activity of peroxidase-like and promote IONPs to catalyze the production of more·OH for killing *** IONPs synergistic treatment,the antibacterial rate of Escherichia coli and Staphylococcus aureus reached nearly 100%.It also has an obvious killing effect on bacteria in infected wounds of mice and can effectively promote the healing of *** wounds,which has great application potential in clinical anti-infection treatment.

关键词： antibacterial photothermal therapy peroxidase-like catalytic therapy

Person-independent expression recognition based on person-similarity weighted expression feature

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Journal of Systems Engineering and Electronics 2010年第1期21卷 118-126页

作者： Huachun Tan Yujin Zhang Hao Chen yanan zhao Wuhong Wang Department of Transportation Engineering Beijing Institute of Technology Beijing 100081 E R. China Department of Electronic Engineering Tsinghua University Beijing 100084 E R. China

A new method to extract person-independent expression feature based on higher-order singular value decomposition （HOSVD） is proposed for facial expression recognition. Based on the assumption that similar persons have similar facial expression appearance and shape, the person-similarity weighted expression feature is proposed to estimate the expression feature of test persons. As a result, the estimated expression feature can reduce the influence of individuals caused by insufficient training data, and hence become less person-dependent. The proposed method is tested on Cohn-Kanade facial expression database and Japanese female facial expression （JAFFE） database. Person-independent experimental results show the superiority of the proposed method over the existing methods.

关键词： facial expression recognition person-independent ex-pression feature higher-order singular value decomposition feature estimation.

Dynamic evolution and trend prediction of multi-scale green innovation in China

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Geography and Sustainability 2023年第3期4卷 222-231页

作者： Xiaohua Xin Lachang Lyu yanan zhao College of Resource Environment and Tourism Capital Normal UniversityBeijing 100048China Beijing Urban Innovation and Development Research Center Beijing 100048China

Numerous studies deal with spatial analysis of green innovation(GI).However,researchers have paid limited attention to analyzing the multi-scale evolution patterns and predicting trends of GI in *** paper seeks to address this research gap by examining the multi-scale distribution and evolutionary characteristics of GI activities based on the data from 337 cities in China during *** used scale variance and the two-stage nested Theil decomposition method to examine the spatial distribution and inequalities of GI in China at multiple scales,including regional,provincial,and ***,we utilized the Markov chain and spatial Markov chain to explore the dynamic evolution of GI in China and predict its long-term *** findings indicate that GI in China has a multi-scale effect and is highly sensitive to changes in spatial scale,with significant spatial differences of GI decreasing in each ***,the spatiotemporal evolution of GI is influenced by both geospatial patterns and spatial scales,exhibiting the“club convergence”effect and a tendency to transfer to higher levels of *** effect is more pronounced on a larger scale,but it is increasingly challenging to transfer to higher *** study also indicates a steady and sustained growth of GI in China,which concentrates on higher levels over *** results contribute to a more precise understanding of the scale at which GI develops and provide a scientific basis and policy suggestions for optimizing the spatial structure of GI and promoting its development in China.

关键词： Green innovation Spatial pattern Trend prediction Multi-scale China

Microstructural Evolution of Plastic Deformation of NiTi Shape Memory Alloy at Low Temperature

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Journal of Wuhan University of Technology(Materials Science) 2013年第5期28卷 1034-1037页

作者：张艳秋江树勇 zhao yanan TANG Ming Industrial Training Centre Harbin Engineering University

Nickel-titanium shape memory alloy （NiTi SMA） which possesses crystal structure of B2 austenite at room temperature was subjected to plastic deformation at low temperature （-150 ℃） by means of local canning compression. The microstructural evolution of NiTi SMA at the different deformation degree was investigated by transmission electron microscopy （TEM） and high resolution transmission electron microscopy （HRTEM）. At the deformation degree by 15%, a high density of dislocations occurs in the deformed NiTi sample. At the deformation degree by 25%, the deformed NiTi sample exhibits the martensite morphology due to the pinning of dislocations at the grain boundaries. At the deformation degree by 50%, a small amount of nanocrystalline phase arises in the deformed NiTi sample. At the deformation degree by 80%, severe plastic deformation （SPD） leads to the occurrence of a great deal of amorphous and nanocrystalline phase,

关键词： NiTi alloy severe plastic deformation shape memory alloy amorphization nanocrystallization