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Additive Hazards Regression with Random Effects for Clustered Failure Times

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Acta Mathematica Sinica,English Series 2015年第3期31卷 511-525页

作者： Deng PAN Yan Yan LIU yuan shan wu Department of Statistics Chinese University of Hong Kong School of Mathematics and Statistics Wuhan University

Additive hazards model with random effects is proposed for modelling the correlated failure time data when focus is on comparing the failure times within clusters and on estimating the correlation between failure times from the same cluster, as well as the marginal regression parameters. Our model features that, when marginalized over the random effect variable, it still enjoys the structure of the additive hazards model. We develop the estimating equations for inferring the regression parameters. The proposed estimators are shown to be consistent and asymptotically normal under appropriate regularity conditions. Furthermore, the estimator of the baseline hazards function is proposed and its asymptotic properties are also established. We propose a class of diagnostic methods to assess the overall fitting adequacy of the additive hazards model with random effects. We conduct simulation studies to evaluate the finite sample behaviors of the proposed estimators in various scenarios. Analysis of the Diabetic Retinopathy Study is provided as an illustration for the proposed method.

关键词： Additive hazards regression clustered failure times counting process empirical process,frailty model checking random effects

Adaptive Penalized Weighted Least Absolute Deviations Estimation for the Accelerated Failure Time Model

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Acta Mathematica Sinica,English Series 2020年第7期36卷 812-828页

作者： Ming Qiu WANG yuan shan wu Qing Long YANG School of Statistics Qufu Normal UniversityQufu 273165P.R.China School of Statistics and Mathematics Zhongnan University of Economics and LawWuhan 430073P.R.China

The accelerated failure time model always offers a valuable complement to the traditional Cox proportional hazards model due to its direct and meaningful *** propose a variable selection method in the context of the accelerated failure time model for survival data,which can simultaneously complete variable selection and parameter ***,the proposed method can deal with the potential outliers in survival times as well as heteroscedastic model errors,which are frequently encountered in ***,utilizing the general nonconvex penalty,we propose the adaptive penalized weighted least absolute deviation estimator for the accelerated failure time *** some regularity conditions,we show that the proposed method yields consistent estimator and possesses the oracle *** addition,we propose a new algorithm to compute the estimate in the high dimensional settings,and evaluate the practical utility of the proposed method through extensive simulation studies and two real examples.

关键词： estimation. property. estimator

A New Robust Risk Measure:Quantile Shortfall

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Acta Mathematica Sinica,English Series 2020年第9期36卷 1014-1024页

作者： You Li CHEN Yan Yan LIU Guang Cai MAO yuan shan wu Fei YAN Law School Wuhan UniversityWuhan 430072P.R.China School of Mathematics and Statistics Wuhan UniversityWuhan 430072P.R.China School of Mathematics and Statistics Central China Normal UniversityWuhan 430079P.R.China School of Statistics and Mathematics Zhongnan University of Economics and LawWuhan 430073P.R.China

Among recent measures for risk management,value at risk(VaR)has been criticized because it is not coherent and expected shortfall(ES)has been criticized because it is not robust to ***,[***.,38,393–417(2013)]proposed a risk measure called median shortfall(MS)which is distributional robust and easy to *** this paper,we propose a more generalized risk measure called quantile shortfall(QS)which includes MS as a special *** measures the conditional quantile loss of the tail risk and inherits the merits of *** construct an estimator of the QS and establish the asymptotic normality behavior of the *** simulation shows that the newly proposed measures compare favorably in robustness with other widely used measures such as ES and VaR.

关键词： Nonparametric estimation quantile shortfall risk measure robust

Theoretical study of superradiant masing with solid-state spins at room temperature

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Science China(Physics,Mechanics & Astronomy) 2024年第6期67卷 38-47页

作者： Qilong wu yuan Zhang Hao wu Shi-Lei Su Kai-Kai Liu Mark Oxborrow Chong-Xin shan Klaus Mølmer Henan Key Laboratory of Diamond Optoelectronic Materials and Devices Key Laboratory of Material Physics Ministry of EducationSchool of Physics and MicroelectronicsZhengzhou UniversityZhengzhou 450052China Institute of Quantum Materials and Physics Henan Academy of SciencesZhengzhou 450046China Center for Quantum Technology Research and Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements School of PhysicsBeijing Institute of TechnologyBeijing 100081China Beijing Academy of Quantum Information Sciences Beijing 100193China Department of Materials Imperial College LondonLondon SW72AZUK Niels Bohr Institute University of CopenhagenCopenhagen 2100Denmark

Steady-state superradiance and superradiant lasing attract significant attentions in the field of optical lattice clocks,but have not been achieved yet due to the technical challenges and atom loss *** this article,we propose that their counter-part may be observed in the microwave domain with solid-state spins,i.e.,nitrogen-vacancy center spins and pentacene molecular spins,coupled to microwave resonator at room temperature with realistic technical *** validate our proposal,we investigate systematically the system dynamics and steady-state by solving quantum master equations for the multi-level and multi-process dynamics of trillions of *** calculations show that the superradiant Rabi oscillations occur firstly due to transitions among different Dicke states,and the subsequent continuous-wave superradiant masing can achieve a linewidth well below *** work may guide further exploration of transient and steady-state superradiant masing with the mentioned and other solid-state spins *** ultra-narrow linewidth may find applications in deep-space communications,radio astronomy and high-precision metrology.

关键词： solid-state spins superradiance maser

Reducibility of Three Dimensional Skew Symmetric System with High Dimensional Weak Liouvillean Frequencies

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Acta Mathematica Sinica,English Series 2024年第10期40卷 2388-2410页

作者： Jie LIU yuan shan Jing WANG School of Mathematics and Statistics Nanjing University of Science and Technology School of Statistics and Data Science Nanjing Audit University

In this paper, we consider the reducibility of three-dimensional skew symmetric *** obtain a reducibility result if the base frequency is high-dimensional weak Liouvillean and the parameter is sufficiently small. The ... 详细信息

关键词： 34C20 37J40 high-dimensional weak Liouvillean KAM theory three dimensional skew-symmetric system

Enhanced visible light absorption of Bi_(2)WO_(6)/SiO_(2) with abundant adsorbed oxygen for the degradation of organic pollutant

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Particuology 2024年第5期88卷 210-217页

作者： yuanting wu Xiaoying Wang Wenlong Zhong shan Zhang School of Material Science and Engineering Shaanxi University of Science and TechnologyXi'an 710021China

Heterogeneous photocatalysts exhibit high catalytic efficiency in the degradation of pollutants,but their stability and repeatability is not very good and requires high structural *** by nanosizing the pure Bi_(2)WO_(6)(BWO)photocatalyst without constructing a heterojunction,there is a significant improvement in its performance,with an enhancement effect of about 2.3 times(99.43%).The high photocatalytic degradation efficiency of the material can be attributed to the enhanced light absorption effect brought by the three-dimensional inverse-opal structure SiO_(2)(IS)and the abundant surface adsorbed oxygen generated after the formation of Si–O–W *** addition,the introduction of IS greatly increases the surface area of nanostructured BWO,which accelerates the charge transfer process,while the adsorbed oxygen promotes the participation of·O^(2−) in the photocatalytic reaction,thereby accelerating the consumption of photo-generated electrons and ultimately improving the separation of charge ***,the matched photonic bandgap further improves the absorption and utilization of light of the *** this work,we constructs Si–O–W bonds to obtain inverse-opal SiO_(2)/Bi_(2)WO_(6) with uniformly growth of pure phase nano BWO,which provides a feasible strategy for the preparation of high-performance pure-phase photocatalysts.

关键词： Bi_(2)WO_(6) SiO_(2) inverse-opal structure Photocatalysis Adsorbed oxygen

Development of component stiffness equations for thread-fixed one-side bolt connections to an enclosed rectangular hollow section column under tension

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Frontiers of Structural and Civil Engineering 2024年第4期18卷 568-586页

作者： Fu-Wei wu yuan-Qi LI Department of Structural Engineering Tongji UniversityShanghai 200092China State Key Laboratory of Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China

The derivation and validation of analytical equations for predicting the tensile initial stiffness of threadfixed one-side bolts(TOBs),connected to enclosed rectangular hollow section(RHS)columns,is presented in this *** unknown stiffness components are considered:the TOBs connection and the enclosed RHS ***,the trapezoidal thread of TOB,as an equivalent cantilevered beam subjected to uniformly distributed loads,is analyzed to determine the associated *** on the findings,the thread-shank serial-parallel stiffness model of TOB connection is *** analysis of the tensile stiffness of the enclosed RHS face due to two bolt forces,the four sidewalls are treated as rotation constraints,thus reducing the problem to a two-dimensional plate *** to the load superposition method,the deflection of the face plate is resolved into three components under various boundary and load *** to the plate deflection theory of Timoshenko,the analytical solutions for the three deflections are derived in terms of the variables of bolt spacing,RHS thickness,height to width ratio,***,the validity of the above stiffness equations is verified by a series of finite element(FE)models of T-stub *** proposed component stiffness equations are an effective supplement to the component-based method.

关键词： initial stiffness component based method thread-fixed one-side bolt rectangular hollow sections analytical equation

Reliability-based life-cycle cost seismic design optimization of coastal bridge piers with nonuniform corrosion using different materials

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Earthquake Engineering and Engineering Vibration 2024年第1期23卷 209-225页

作者： wu Xiangtong yuan Wenting Guo Anxin Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology Harbin Institute of TechnologyHarbin 150090China Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of TechnologyHarbin 150090China Institute of Transportation Inner Mongolia UniversityHohhot 010070China

Reinforcement corrosion is the main cause of performance deterioration of reinforced concrete(RC)*** research has been performed to investigate the life-cycle cost(LCC)of coastal bridge piers with nonuniform corrosion using different *** this study,a reliability-based design optimization(RBDO)procedure is improved for the design of coastal bridge piers using six groups of commonly used materials,i.e.,normal performance concrete(NPC)with black steel(BS)rebar,high strength steel(HSS)rebar,epoxy coated(EC)rebar,and stainless steel(SS)rebar(named NPC-BS,NPC-HSS,NPC-EC,and NPC-SS,respectively),NPC with BS with silane soakage on the pier surface(named NPC-Silane),and high-performance concrete(HPC)with BS rebar(named HPC-BS).First,the RBDO procedure is improved for the design optimization of coastal bridge piers,and a bridge is selected to illustrate the ***,reliability analysis of the pier designed with each group of materials is carried out to obtain the time-dependent reliability in terms of the ultimate and serviceability ***,the repair time of the pier is predicted based on the time-dependent reliability ***,the time-dependent LCCs for the pier are obtained for the selection of the optimal design.

关键词： reliability-based design optimization(RBDO) life-cycle cost(LCC) nonuniform corrosion coastal bridge pier repair

New phenylbutenoids and terpene glycosides from Ginkgo biloba leaves

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Chinese Journal of Natural Medicines 2024年第2期22卷 161-170页

作者： SUN Zeshi LIN shan wu Zhi-Li DONG Hong-yuan XU Xi-Ke LI Hui-Liang WANG Jinxin School of Pharmacy Second Military Medical UniversityShanghai 200433China State Key Laboratory of New Drug and Pharmaceutical Process Shanghai Institute of Pharmaceutical IndustryChina State Institute of Pharmaceutical IndustryShanghai 201203China

Our continued works on the chemical constituents of Ginkgo biloba(***)leaves has led to the isolation of two novel phenylbutenoids(1,2),along with five previously unidentified terpene glycosides(3−7).Among them,compounds 1 and 2 represent unique(Z)-phenylbutenoids,3−6 are megastigmane glycosides,and 7 is identified as a rare bilobanone glycoside(Fig.1).This study marks the first reported isolation of phenylbutenoid and bilobanone glycoside from *** chemical structures of these compounds were elucidated through extensive spectroscopic analysis,including HR-ESI-MS and various 1D and 2D NMR ***,the absolute configurations of these molecules were determined using Mosher’s method,ECD experiments,and Cu-KαX-ray crystallographic analyses.

关键词： Ginkgo biloba Phenylbutenoid Megastigmane glycoside Bilobanone glycoside