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Semantic segmentation via pixel-to-center similarity calculation

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CAAI Transactions on Intelligence Technology 2024年第1期9卷 87-100页

作者： dongyue Wu Zilin Guo Aoyan li Changqian Yu Nong Sang Changxin Gao National Key Laboratory of Science and Technology on Multispectral Information Processing School of Artificial Intelligence and AutomationHuazhong University of Science and TechnologyWuhanChina Meituan Inc. BeijingChina

Since the fully convolutional network has achieved great success in semantic segmentation,lots of works have been proposed to extract discriminative pixel representations.However,the authors observe that existing methods still suffer from two typical challenges:(i)The intra-class feature variation between different scenes may be large,leading to the difficulty in maintaining the consistency between same-class pixels from different scenes;(ii)The inter-class feature distinction in the same scene could be small,resulting in the limited performance to distinguish different classes in each scene.The authors first rethink se-mantic segmentation from a perspective of similarity between pixels and class centers.Each weight vector of the segmentation head represents its corresponding semantic class in the whole dataset,which can be regarded as the embedding of the class center.Thus,the pixel-wise classification amounts to computing similarity in the final feature space between pixels and the class centers.Under this novel view,the authors propose a Class Center Similarity(CCS)layer to address the above-mentioned challenges by generating adaptive class centers conditioned on each scenes and supervising the similarities between class centers.The CCS layer utilises the Adaptive Class Center Module to generate class centers conditioned on each scene,which adapt the large intra-class variation between different scenes.Specially designed Class Distance Loss(CD Loss)is introduced to control both inter-class and intra-class distances based on the predicted center-to-center and pixel-to-center similarity.Finally,the CCS layer outputs the processed pixel-to-center similarity as the segmentation prediction.Extensive experiments demonstrate that our model performs favourably against the state-of-the-art methods.

关键词： computer vision deep neural networks image segmentation scene understanding

Cryogenic mechanical behavior of a TRIP-assisted dual-phase highentropy alloy

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Nano Research 2022年第6期15卷 4859-4866页

作者： dongyue li Zhiming li Lu Xie Yong Zhang Wenrui Wang School of Mechanical Engineering University of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering Central South UniversityChangsha 410083China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China

The recently developed dual-phase(DP)non-equiatomic Fe_(50)Mn_(30)Co_(10)Cr_(10)(at.%)high-entropy alloy(HEA)showed much higher strength and ductility compared to the single-phase equiatomic Fe_(20)Mn_(20)Ni_(20)Co_(20)Cr_(20)(at.%)HEA at room temperature.Herein we probe the cryogenic mechanical properties of the non-equiatomic DP-HEA with different grain sizes and compare with the equiatomic single-phase HEA.Our results show that the cryogenic ultimate tensile strengths of the coarse-grained(~200μm)and fine-grained(~4μm)DP-HEAs reach up to 1,133 and 1,342 MPa,respectively,which are significantly higher than that of the equiatomic single-phase HEAs with similar grain sizes.Furthermore,the fine-grained DP-HEA shows substantial improvement in both strength and ductility compared to the coarse-grained counterparts at cryogenic temperatures.Microstructural analysis reveals that the enhanced mechanical properties of the DP-HEA at cryogenic temperatures are attributed to a more extensive displacive transformation from the face-centered cubic(FCC)matrix into the hexagonal close-packed(HCP)phase compared to that at room temperature.Specifically,the HCP phase fraction in tensile tested fine-grained DP-HEAs increases from~39%to~79%with decreasing temperature from 298 to 77 K.The enhanced transformation behavior is enabled by the reduced stacking fault energy of the material with the decrease of deformation temperatures.The resulting outstanding combination of strength and ductility further suggests that the DP-HEAs are promising candidates as structural materials for cryogenic applications.

关键词： high-entropy alloy cryogenic mechanical behavior grain size dual phase phase transformation

Effect of Zr on phase separation,mechanical and corrosion behavior of heterogeneous CoCrFeNiZr_(x) high-etropy alloy

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Journal of Materials Science & Technology 2022年第14期109卷 76-85页

作者： Wu Qi Wenrui Wang Xiao Yang Lu Xie Jiaming Zhang dongyue li Yong Zhang School of Mechanical Engineering University of Science and Technology BeijingBeijing 100083China Key Laboratory of Fluid Interaction with Material Ministry of EducationBeijing 100083China Key Laboratory of Cryogenics Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China

CoCrFeNi high entropy alloy(HEA)has attracted extensive attention due to its excellent corrosion resistance,but the low strength limits its engineering application prospects.In order to develop CoCrFeNi based HEAs with high strength,ductility and corrosion resistance,the effects of Zr content on the microstructure,mechanical properties and corrosion resistance of heterogeneous CoCrFeNiZr_(x)(x=0,0.25,0.5 and 1)HEAs were investigated in this work.The results indicate that the increase of Zr content can significantly affect the phase stability of the alloy,and promote the formation of intermetallic compounds(Ni_(7)Zr_(2)and/or Laves phase)and the transformation of solid solution from face-centered cubic(FCC)structure(x=0,0.25 and 0.5)to body-centered cubic(BCC)structure(x=1).Reasonable control of the Zr content can endow the alloy excellent comprehensive properties.Especially,for CoCrFeNiZr_(0.25) alloy,composed of FCC matrix and a small amount of Ni_(7)Zr_(2)phases,the yield strength(~655 MPa)is increased by nearly four times higher than that of Zr-free alloy,and it also has good ductility(fracture stain>50%).Meanwhile,the corrosion resistance of CoCrFeNiZr_(0.25) alloy is better than that of SS304.The EIS results show that the addition of Zr reduces the stability of the passive film on the alloy,which can be related to the content of the beneficial oxide in the passive film and the thickness of the passive film through XPS analysis.Moreover,the work functions of different phases in CoCrFeNiZr_(x)alloys were obtained by firstprinciples calculations,which further confirmed the selective corrosion mechanism of the CoCrFeNiZr_(x) alloy combining the experimental results.

关键词： High-entropy alloy Microstructure Corrosion resistance First-principles Work function

All-inorganic nitrate electrolyte for high-performance lithium oxygen battery

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Nano Research 2024年第5期17卷 4163-4170页

作者： dongyue Yang Jiayi Du Kai Chen Haoran Zhang Gang Huang Tong liu Xinbo Zhang Hongjie Zhang State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026China

lithium-oxygen(li-O_(2))batteries have been regarded as an expectant successor for next-generation energy storage systems owing to their ultra-high theoretical energy density.However,the comprehensive properties of the commonly utilized organic salt electrolyte are still unsatisfactory,not to mention their expensive prices,which seriously hinders the practical production and application of li-O_(2) batteries.Herein,we have proposed a low-cost all-inorganic nitrate electrolyte(liNO_(3)-KNO_(3)-DMSO)for li-O_(2) batteries.The inorganic nitrate electrolyte exhibits higher ionic conductivity and a wider electrochemical stability window than the organic salt electrolyte.The existence of K+can stabilize the O_(2)-intermediate,promoting the discharge process through the solution pathway with an enlarged capacity.Even at an ultra-low concentration of 0.01 M,the K+can still remain stable to promote the solution discharge process and also possess a new function of inhibiting the dendrite growth by electrostatic shielding,further enhancing the battery stability and contributing to the long cycle lifetime.As a result,in the 0.99 M liNO_(3)-0.01 M KNO_(3)-DMSO electrolyte,the li-O_(2) batteries exhibit prolonged cycling performance(108 cycles)and excellent rate performance(2 A·g^(-1)),significantly superior to the organic salt one.

关键词： li-O_(2)batteries potassium ions inorganic nitrate electrolyte solution pathway mechanism

Quadrature-based moment methods for the population balance equation: An algorithm review

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Chinese Journal of Chemical Engineering 2019年第3期27卷 483-500页

作者： dongyue li Zhipeng li Zhengming Gao State Key Laboratory of Chemical Resource Engineering School of Chemical Engineering Beijing University of Chemical Technology State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing

The dispersed phase in multiphase flows can be modeled by the population balance model(PBM). A typical population balance equation(PBE) contains terms for spatial transport, loss/growth and breakage/coalescence source terms. The equation is therefore quite complex and difficult to solve analytically or numerically. The quadrature-based moment methods(QBMMs) are a class of methods that solve the PBE by converting the transport equation of the number density function(NDF) into moment transport equations. The unknown source terms are closed by numerical quadrature. Over the years, many QBMMs have been developed for different problems, such as the quadrature method of moments(QMOM), direct quadrature method of moments(DQMOM),extended quadrature method of moments(EQMOM), conditional quadrature method of moments(CQMOM),extended conditional quadrature method of moments(ECQMOM) and hyperbolic quadrature method of moments(Hy QMOM). In this paper, we present a comprehensive algorithm review of these QBMMs. The mathematical equations for spatially homogeneous systems with first-order point processes and second-order point processes are derived in detail. The algorithms are further extended to the inhomogeneous system for multiphase flows, in which the computational fluid dynamics(CFD) can be coupled with the PBE. The physical limitations and the challenging numerical problems of these QBMMs are discussed. Possible solutions are also summarized.

关键词： Population balance equation Quadrature-based moment method Multiphase flow Computational fluid dynamics

Relationship Between Climate Change and Marmot Plague of Marmota himalayana Plague Focus—the Altun Mountains of the Qinghai-Xizang Plateau,China,2000–2022

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China CDC weekly 2024年第4期6卷 69-74,I0006页

作者： Qun Duan Xiaojin Zheng Zhiqiang Gan dongyue Lyu Hanyu Sha Xinmin Lu Xiaoling Zhao Asaiti Bukai Ran Duan Shuai Qin li Wang Jinxiao Xi Di Wu Peng Zhang Deming Tang Zhaokai He Huaiqi Jing Biao Kan Xin Wang National Institute for Communicable Disease Control and Prevention Chinese Center for Disease Control and PreventionBeijingChina Akesai Kazak Autonomous County Center for Disease Control and Prevention Jiuquan CityGansu ProvinceChina Jiuquan Center for Disease Control and Prevention Jiuquan CityGansu ProvinceChina Gansu Provincial Center for Disease Control and Prevention Lanzhou CityGansu ProvinceChina

Introduction:Plague is a zoonotic disease that occurs naturally in specific geographic areas.Climate change can influence the populations of the plague host or vector,leading to variations in the occurrence and epidemiology of plague in animals.Methods:In this study,we collected meteorological and plague epidemiological data from the Marmota himalayana plague focus in the Altun Mountains of the Qinghai-Xizang Plateau.The data spanned from 2000 to 2022.We describe the climatic factors and plague epidemic conditions and we describe their analysis by Pearson’s correlation.Results:During the period from 2000 to 2022,the isolation rates of Yersinia pestis(Y.pestis)from marmots and fleas were 9.27%(451/4,864)and 7.17%(118/1,646),respectively.Additionally,we observed a positive rate of F1 antibody of 11.25%(443/3,937)in marmots and 18.16%(142/782)in dogs.With regards to climate,there was little variation,and a decreasing trend in blowing-sand days was observed.The temperature in the previous year showed a negative correlation with the Y.pestis isolation rate in marmots(r=−0.555,P=0.011)and the positive rate of F1 antibody in marmots(r=−0.552,P=0.012)in the current year.The average annual precipitation in the previous two years showed a positive correlation with marmot density(r=0.514,P=0.024),while blowingsand days showed a negative correlation with marmot density(r=−0.701,P=0.001).Furthermore,the average annual precipitation in the previous three years showed a positive correlation with the isolation rate of Y.pestis from marmots(r=0.666,P=0.003),and blowing-sand days showed a negative correlation with marmot density(r=−0.597,P=0.009).Conclusions:The findings of this study indicate that there is a hysteresis effect of climate change on the prevalence of plague.Therefore,monitoring climate conditions can offer significant insights for implementing timely preventive and control measures to combat plague epidemics.

关键词： Plague epidemiology Plateau

Compressibility induced bubble size variation in bubble column reactors:Simulations by the CFD–PBE

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Chinese Journal of Chemical Engineering 2018年第10期26卷 2009-2013页

作者： dongyue li Zhipeng li Zhengming Gao State Key Laboratory of Chemical Resource Engineering School of Chemical Engineering Beijing University of Chemical Technology

Bubble column reactors can be simulated by the two fluid model(TFM) coupled with the population balance equation(PBE). For the large industrial bubble columns, the compressibility due to the pressure difference may introduce notable bubble size variation. In order to address the compressibility effect, the PBE should be reformulated and coupled with the compressible TFM. In this work, the PBE with a compressibility term was formulated from single bubble dynamics, the mean Sauter diameters predicted by the compressible TFM coupled with the PBE were compared with the analytical solutions obtained by the ideal gas law. It was proven that the mesoscale formulations presented in this work were physically consistent with the macroscale modeling. It can be used to simulate large industrial plants when the compressibility induced bubble size variation is important.

关键词：尺寸变化可压缩 PBE 反应堆水泡 CFD 模拟平衡方程

Attitudes toward income inequality:perspectives from farmers living in a poverty-stricken rural area of China

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Chinese Journal of Population,Resources and Environment 2016年第3期16卷 159-166页

作者： Hongjie Wang dongyue li College of Economics and Management Huazhong Agricultural University

The attitude of the least advantaged people to income inequality is important in regard to social stability,which is also a major concern of the government and researchers in China.This paper aimed to investigate the perceptions and attitudes of the least advantaged people toward income inequality in China.An empirical analysis was conducted on farmers' attitudes to income inequality based on a questionnaire survey of 308 farmers in four villages in Yingshan,Hubei Province.Our results show that the respondents consider the income inequality as severe,and ability,hard work,and individual choices are the major determinant factors of income.It is shown that farmers in less developed areas are more likely to accept income inequality,and they ascribe this to their own failure rather than to social injustice.However,it is not the case that people living in poverty-stricken areas are satisfied with antipoverty policies;and these policies are expected to be further improved to increase the income of the poor.

关键词： Anti-poverty policy income inequality poverty-stricken areas justice China

AN IMPROVED RANDOM WALK SEGMENTATION ON THE LUNG NODULES

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International Journal of Biomathematics 2013年第6期6卷 105-120页

作者： li GUO YUNTING ZHANG ZEWEI ZHANG dongyue li School of Medical Imaging Tianjin Medical University Tianjin 300203 P. R. China General Hospital Radiology Tianjin Medical University Tianjin 300203 P. R. China

In this paper, we proposed a semi-automatic technique with a marker indicating the target to locate and segment nodules. For the lung nodule detection, we develop a Gabor texture feature by FCM (Fuzzy C Means) segmentation. Given a marker indicating a rough location of the nodules, a decision process is followed by applying an ellipse fitting algorithm. From the ellipse mask, the foreground and background seeds for the random walk segmentation can be automatically obtained. Finally, the edge of the nodules is obtained by the random walk algorithm. The feasibility and effectiveness of the proposed method are evaluated with the various types of the nodules to identify the edges, so that it can be used to locate the nodule edge and its growth rate.

关键词：结节分割随机游动肺拟合算法随机游走模糊C均值 Gabor