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Acta Mathematica Sinica,English Series 2024年第4期40卷 985-999页

作者： yi DENG Qiang XIONG Shu Wei li School of Economics and Statistics Guangzhou UniversityGuangzhou 510006P.R.China

Recurrent event data are commonly encountered in many scientific fields,including biomedical studies,clinical trials and epidemiological surveys,and many statistical methods have been proposed for their *** this paper,we consider to use a weighted composite endpoint of recurrent and terminal events,which is weighted by the severity of each event,to assess the overall effects of covariates on the two types of events.A flexible additive-multiplicative model incorporating both multiplicative and additive effects on the rate function is proposed to analyze such weighted composite event process,and more importantly,the dependence structure among the recurrent and terminal events is left *** the estimation,we construct the unbiased estimating equations by virtue of the inverse probability weighting technique,and the resulting estimators are shown to be consistent and asymptotically normal under some mild regularity *** evaluate the finite-sample performance of the proposed method via simulation studies and apply the proposed method to a set of real data arising from a bladder cancer study.

关键词： Additive-multiplicative rates model estimating equation recurrent events terminal event weighted composite endpoint

Characteristics of Particulate Matter Emissions for Low-Sulfur Heavy Oil Used in Low-Speed Two-Stroke Diesel Engines of Ocean-Going Ships

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Journal of Thermal Science 2024年第2期33卷 739-750页

作者： WU gang MA Qianli WEI lijiang JIANG Guohe WANG Tengfei li Tie Merchant Marine College Shanghai Maritime UniversityShanghai201306China State Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai200240China

In this work,particulate matter(PM) emissions from a large two-stroke,low-speed marine diesel engine were investigated when the engine was operated with low-sulfur heavy fuel oil(HFO) at various *** samples were collected in situ from the engine exhaust to determine the detailed physical and chemical *** nanostructure and morphology of the nanoparticles were analyzed using transmission electron microscopy images(TEM).The results show that volatile organic carbon(OC) accounts for more than 80% in the HFO particles and leads to an increase in particle *** thermodynamic conditions of a low-speed engine favor the behavior of capturing the soluble organic components.A large number of spherical char HFO particles with aerodynamic diameters of 0.2 μm-0.5 μm and a suspected inner metal core were *** two peak aerodynamic diameters of the HFO nanoparticles are 15 nm and 86 *** morphological differences among the HFO nanoparticles in varied engine conditions represent the formation process from primary nascent particles to mature graphitized particles caused by *** above study will be valuable for understanding the characteristics of PM emissions from low-sulfur HFO to achieve the ship PM emissions reduction target.

关键词： low-speed diesel engine maritime regulations heavy fuel oil TEM particles size and distribution

An approximate analytical model for unconventional reservoir considering variable matrix blocks and simultaneous matrix depletion

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Petroleum Science 2024年第1期21卷 352-365页

作者： Kai-Xuan Qiu Jia li Dong Feng Shi-Ming Wei gang Lei Jiangmen Laboratory of Carbon Science and Technology Jiangmen529100GuangdongChina The Hong Kong University of Science and Technology(Guangzhou) Guangzhou511400GuangdongChina China University of Geosciences(Beijing) Beijing100083China China University of Petroleum(Beijing) Beijing102249China China University of Geosciences(Wuhan) Wuhan430074HubeiChina Shenzhen Research Institute China University of GeosciencesShenzhen518063GuangdongChina

In regard to unconventional oil reservoirs,the transient dual-porosity and triple-porosity models have been adopted to describe the fluid flow in the complex fracture *** has been proven to cause inaccurate production evaluations because of the absence of matrix-macrofracture *** addition,most of the existing models are solved analytically based on Laplace transform and numerical ***,an approximate analytical solution is derived directly in real-time space considering variable matrix blocks and simultaneous matrix *** simplify the derivation,the simultaneous matrix depletion is divided into two parts:one part feeding the macrofractures and the other part feeding the ***,a series of partial differential equations(PDEs)describing the transient flow and boundary conditions are constructed and solved analytically by ***,a relationship between oil rate and production time in real-time space is *** new model is verified against classical analytical *** the microfracture system and matrix-macrofracture communication is neglected,the result of the new model agrees with those obtained with the dual-porosity and triple-porosity model,***,the new model also has an excellent agreement with the numerical *** model is then applied to two actual tight oil wells completed in western Canada sedimentary *** identifying the flow regime,the solution suitably matches the field production data,and the model parameters are *** these output parameters,we can accurately forecast the production and even estimate the petrophysical properties.

关键词： Analytical solution Unconventional reservoir Variable matrix Simultaneous flow

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

Milestone progress of the HEPS booster commissioning

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Nuclear Science and Techniques 2024年第1期35卷 170-177页

作者： Yue-Mei Peng Jian-She Cao Jin-Hui Chen Hai-yi Dong Ping He yi Jiao ling Kang Wen Kang Jian li Jing-yi li Guo-Ping lin Fang liu Feng-li Long Cai Meng Xin Qi Hua-Min Qu Yan-Feng Sui Sheng Wang gang Xu Qiang Ye Jing Zhang Pei Zhang Wei-Min Pan Key Laboratory of Particle Acceleration Physics and Technology Institute of High Energy PhysicsChinese Academy of Sciences19B Yuquan RoadShijingshan DistrictBeijing 100049China University of the Chinese Academy of Sciences 19A Yuquan RoadShijingshan DistrictBeijing 100049China

The high-energy photon source(HEPS)is the first fourth-generation synchrotron light source facility in *** HEPS injector consists of a linear accelerator(linac)and a full energy *** booster captures the electron beam from the linac and increases its energy to the value required for the storage *** full-energy beam could be injected to the storage ring directly or after“high-energy accumulation.”On November 17,2023,the key booster parameters successfully reached their corresponding target *** milestone results were achieved based on numerous contributions,including nearly a decade of physical design,years of equipment development and installation,and months of beam *** measured at the extraction energy of 6 GeV,the averaged beam current and emittance reached 8.57 mA with 5 bunches and 30.37 nm rad with a single-bunch charge of 5.58 nC,compared with the corresponding target values of 6.6 mA and 35 nm rad,*** paper presents the physical design,equipment development,installation,and commissioning process of the HEPS booster.

关键词： High energy photon source Booster Beam commissioning

Efficient micrometer-scale thick-film perovskite solar cells with superior stability

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Rare Metals 2024年第4期43卷 1647-1657页

作者： Jian-Fei Hu gang Chen Shun-Zhang Yu Yue-Xin lin Kai-Yu Wang Zong-Wei li Guo-Dong Zhang Teng-Fei Pan Ya-Jing li Ming-Jie li ying-Dong Xia yi-Fan Lv Yong-Hua Chen Key Laboratory of Flexible Electronics(KLoFE)and Institute of Advanced Materials(IAM) School of Flexible Electronics(Future Technologies)Nanjing Tech University(NanjingTech)Nanjing211816China Department of Applied Physics The Hong Kong Polytechnic UniversityHong Kong999077China Shenzhen Research Institute The Hong Kong Polytechnic UniversityShenzhen518057China Optics Valley Laboratory Hubei430074China

It is essential to enhance the thickness of the absorber layer for perovskite solar cells(PSCs)to improve device performance and reduce industry ***,thick perovskite films(>1μm)are difficult to be fabricated by employing traditional solvents,such as N,N-dimethylformamide(DMF),dimethyl sulfoxide(DMSO).Besides,it is a challenge to fabricate thick-film perovskite owing to the deteriorated surface morphology and serious defect ***,a simple method was reported to deposit uniform pinhole-free perovskite films with a thickness of more than 2μm utilizing the methylamine acetate(MAAc)ionic liquid as the *** with methylammonium chloride(MACl)as an additive,thick-film perovskite with~2μm in grain size and few grain boundaries(GBs)was prepared,which dramatically improved the perovskite crystal quality and enhanced carrier transport *** final PSCs exhibited a power conversion efficiency(PCE)of 20.16%.The device showed improved stability with 95%of its initial efficiency in a nitrogen environment over 5000 *** work provides an alternative strategy to produce extremely efficient and stable thick-film *** can be believed that this device has great potential in the application of large areas and laminated PSCs.

关键词： Perovskite solar cells Thick-film Stability Ionic liquid

Humanoid robot heads for human-robot interaction:A review

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Science China(Technological Sciences) 2024年第2期67卷 357-379页

作者： li yi ZHU liXiang ZHANG ZiQian GUO MingFei li ZhiXin li YanBiao HASHIMOTO Minoru Key Laboratory of Special Purpose Equipment and Advanced Processing Technology of Ministry of Education Zhejiang University of TechnologyHangzhou 310023China Zhejiang Provincial Key Laboratoryof Special Purpose Equipment and Advanced Processing Technology Zhejang Universityof Technology Hangzhou 310023 China Faculy of Textile Science and Technology Shinshu UniversityUeda 386-8567Japan

The humanoid robot head plays an important role in the emotional expression of human-robot interaction(HRI).They are emerging in industrial manufacturing,business reception,entertainment,teaching assistance,and tour *** recent years,significant progress has been made in the field of humanoid ***,there is still a lack of humanoid robots that can interact with humans naturally and *** review comprises a comprehensive survey of state-of-the-art technologies for humanoid robot heads over the last three decades,which covers the aspects of mechanical structures,actuators and sensors,anthropomorphic behavior control,emotional expression,and human-robot ***,the current challenges and possible future directions are discussed.

关键词： humanoid robot head anthropomorphic behaviors emotional expression human-robot interaction

To improve robustness of mechanical properties of semi-solid cast A356 alloy using taguchi design method

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China Foundry 2024年第2期21卷 175-184页

作者： yi-wu Xu Hong-yi Zhan Wei Tong Jin-ping li Le-peng Zhang De-jiang li Xiao-qin Zeng School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China China Science Lab General Motors Global Research&DevelopmentShanghai 201206China General Motors(China)Investment Co. Ltd.Shanghai 201206China China International Intellectech Corporation(CIIC) Beijing 100004China

Mechanical properties of semi-solid casting are dependent on multiple processing parameters,and improper processing parameters will not only reduce mean data but also increase *** present study investigated the impact of parameters in slurry preparation and heat treatment on the yield strength and ductility of T6 heat-treated A356 Al-Si alloy using rapid slurry forming(RSF)semi-solid *** focus was primarily on the robustness of mechanical properties based on Taguchi design *** analyzing signal-to-noise ratio and minimum value calculated from-3S,the optimum slurry preparation parameters and heat treatment parameters were determined to be no quench,enthalpy exchange material(EEM)temperature of 140℃,EEM-to-melt ratio of 6mass%,stirring time of 18 s,solution heat treated at 520℃ for 2 h,and ageing heat treated at 190℃ for 6 *** a small batch validation,the-3S yield strength and-3S elongation reach 256.1 MPa and 5.03% respectively,showing a satisfactory *** hardness and microstructure of heat-treated samples with the best and worst properties were characterized to gain insight into the underlying mechanisms affecting the mean value and variations of mechanical properties.

关键词： semi-solid casting taguchi design method signal-to-noise ratio mechanical property microstructure

Single-cell RNA sequencing to understand host-virus interactions

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Virologica Sinica 2024年第1期39卷 1-8页

作者： Jia-Tong Chang li-Bo liu Pei-gang Wang Jing An Department of Microbiology School of Basic Medical SciencesCapital Medical UniversityBeijing 100069China

Single-cell RNA sequencing(scRNA-seq)has allowed for the profiling of host and virus transcripts and host-virus interactions at single-cell *** review summarizes the existing scRNA-seq technologies together with their strengths and *** applications of scRNA-seq in various virological studies are discussed in depth,which broaden the understanding of the immune atlas,host-virus interactions,and immune ***-seq can be widely used for virology in the near future to better understand the pathogenic mechanisms and discover more effective therapeutic strategies.

关键词： Single-cell RNA sequencing(scRNA-seq) Host-virus interaction COVID-19 Flavivirus

Identifying malicious traffic under concept drift based on intraclass consistency enhanced variational autoencoder

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Science China(Information Sciences) 2024年第8期67卷 238-252页

作者： Xiang LUO Chang liU Gaopeng GOU gang XIONG Zhen li Binxing FANG Institute of Information Engineering Chinese Academy of Sciences School of Cyber Security University of Chinese Academy of Sciences School of Computer Science and Technology Harbin Institute of Technology (Shenzhen)

Accurate identification of malicious traffic is crucial for implementing effective defense countermeasures and has led to extensive research efforts. However, the continuously evolving techniques employed by adversaries have introduced the issues of concept drift, which significantly affects the performance of existing methods. To tackle this challenge, some researchers have focused on improving the separability of malicious traffic representation and designing drift detectors to reduce the number of false ***, these methods often overlook the importance of enhancing the generalization and intraclass consistency in the representation. Additionally, the detectors are not sufficiently sensitive to the variations among different malicious traffic classes, which results in poor performance and limited robustness. In this paper, we propose intraclass consistency enhanced variational autoencoder with Class-Perception detector(ICE-CP) to identify malicious traffic under concept drift. It comprises two key modules during training:intraclass consistency enhanced(ICE) representation learning and Class-Perception(CP) detector construction. In the first module, we employ a variational autoencoder(VAE) in conjunction with Kullback-Leibler(KL)-divergence and cross-entropy loss to model the distribution of each input malicious traffic flow. This approach simultaneously enhances the generalization, interclass consistency, and intraclass differences in the learned representation. Consequently, we obtain a compact representation and a trained classifier for nondrifting malicious traffic. In the second module, we design the CP detector, which generates a centroid and threshold for each malicious traffic class separately based on the learned representation, depicting the boundaries between drifting and non-drifting malicious traffic. During testing, we utilize the trained classifier to predict malicious traffic classes for the testing samples. Then, we use the CP det

关键词： concept drift cyberspace security intrusion detection malicious traffic identification variational autoencoder

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