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On Pointwise Bounded Approximation

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Acta Mathematica Sinica,English Series 2009年第7期25卷 1217-1222页

作者： zhijian qiu School of Mathematics Southwestern University of Finance and Economics Chengdu 610074 P. R. China

Let G be an open subset in the extended complex plane and let A（G） denote the algebra of all functions analytic on G and continuous on G. We call a domain multi-nicely connected if there is a circular domain W and a conformal map ~ from W onto G such that the boundary value function of φ is univalent almost everywhere with respect to the arclength on aW. Suppose that every component of G is finitely connected and none of the components of G have single point boundary components. We show that for every bounded analytic function on G to be the pointwise limit of a bounded sequence of functions in A（G）, it is necessary and sufficient that each component of G is multi-nicely connected and the harmonic measures of G are mutually singular. This generalizes the corresponding result of Davie for the case when the components of G are simply connected.

关键词： pointwise approximation harmonic measure Dirichlet algebra

OpenSees Three-Dimensional Computational Modeling of Ground-Structure Systems and Liquefaction Scenarios

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Computer Modeling in Engineering & Sciences 2019年第9期120卷 629-656页

作者： zhijian qiu Jinchi Lu Ahmed Elgamal Lei Su Ning Wang Abdullah Almutairi Department of Structural Engineering UC San DiegoLa JollaCA 92093-0085USA School of Civil Engineering Qingdao University of TechnologyQingdao266033China Institute of Geophysics China Earthquake AdministrationBeijing100081China

The OpenSees computational platform has allowed unprecedented opportunities for conducting seismic nonlinear soil-structure interaction *** the geotechnical side,capabilities such as coupled solid-fluid formulations and nonlinear incrementalplasticity approaches allow for representation of the involved dynamic/seismic *** paper presents recent research that facilitated such endeavors in terms of response of ground-foundation-structure systems using advanced material modeling techniques and high-performance computing *** numerical results are shown for large-scale soil-structure systems,and ground modification liquefaction *** addition,graphical user interface enabling tools for routine usage of such 3D simulation environments are presented,as an important element in support of wider adoption and practical *** this context,Performance-Based Earthquake Engineering(PBEE)analysis of bridge-ground systems is highlighted as an important topical application.

关键词： Numerical simulation OpenSees geotechnical earthquake soil liquefaction seismic response

Beurling's theorem and invariant subspaces for the shift on Hardy spaces

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Science China Mathematics 2008年第1期51卷 131-142页

作者： qiu zhijian School of Economic Mathematics, Southwestern University of Finance and Economics, Chengdu 610074, China 1. School of Economic Mathematics Southwestern University of Finance and Economics Chengdu 610074 China

Let G be a bounded open subset in the complex plane and let H 2(G) denote the Hardy space on G. We call a bounded simply connected domain W perfectly connected if the boundary value function of the inverse of the Riemann map from W onto the unit disk D is almost 1–1 with respect to the Lebesgue measure on ?D and if the Riemann map belongs to the weak-star closure of the polynomials in H ∞(W). Our main theorem states: in order that for each M ∈ Lat (M z ), there exist u ∈ H ∞(G) such that M = ∨{uνH 2(G)}, it is necessary and sufficient that the following hold:each component of G is a perfectly connected domainthe harmonic measures of the components of G are mutually singularthe set of polynomials is weak-star dense in H ∞(G).Moreover, if G satisfies these conditions, then every M ∈ Lat (M z ) is of the form uH 2(G), where u ∈ H ∞(G) and the restriction of u to each of the components of G is either an inner function or zero.

关键词： Hardy space invariant subspace shift operator 47B20 30H05 30E10 46E15

Carleson Measures on Planar Sets

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Acta Mathematica Sinica,English Series 2009年第11期25卷 1881-1892页

作者： zhijian qiu School of Mathematics,Southwestern University of Finance and Economics,Chengdu 610074,P. R. China School of Mathematics Southwestern University of Finance and Economics Chengdu 610074 P. R. China

In this paper, we investigate what are Carleson measures on open subsets in the complex plane. A circular domain is a connected open subset whose boundary consists of finitely many disjoint circles. We call a domain G multi-nicely connected if there exists a circular domain W and a conformal map ψ from W onto G such that ψ is almost univalent with respect the arclength on δW. We characterize all Carleson measures for those open subsets so that each of their components is multinicely connected and harmonic measures of the components are mutually singular. Our results suggest the extension of Carleson measures probably is up to this class of open subsets

关键词： Carleson measure circular domain harmonic measure multi-nicely connected domain

Predicting the Prognosis and Immunotherapeutic Response of Triple-Negative Breast Cancer by Constructing a Prognostic Model Based on CD8+T Cell-Related Immune Genes

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Biomedical and Environmental Sciences 2024年第6期37卷 581-593页

作者： Nani Li Xiaoting qiu Jingsong Xue Limu Yi Mulan Chen zhijian Huang Department of Medical Oncology Clinical Oncology School of Fujian Medical UniversityFujian Cancer HospitalFuzhou 350014FujianChina Department of Breast Surgical Oncology Clinical Oncology School of Fujian Medical UniversityFujian Cancer HospitalFuzhou 350014FujianChina Departmen of Pathology Shenzhen Longhua Maternity and Child Healthcare HospitalShenzhen 518109GuangdongChina

Objective Triple-negative breast cancer(TNBC)poses a significant challenge for treatment ***8+T cells,which are pivotal immune cells,can be effectively analyzed for differential gene expression across diverse cell populations owing to rapid advancements in sequencing *** leveraging these genes,our objective was to develop a prognostic model that accurately predicts the prognosis of patients with TNBC and their responsiveness to *** Sample information and clinical data of TNBC were sourced from The Cancer Genome Atlas and METABRIC *** the initial stage,we identified 67 differentially expressed genes associated with immune response in CD8+T ***,we narrowed our focus to three key genes,namely CXCL13,GBP2,and GZMB,which were used to construct a prognostic *** accuracy of the model was assessed using the validation set data and receiver operating characteristic(ROC)***,we employed various methods,including Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway,immune infiltration,and correlation analyses with CD274(PD-L1)to explore the model's predictive efficacy in immunotherapeutic ***,we investigated the potential underlying biological pathways that contribute to divergent treatment *** We successfully developed a model capable of predicting the prognosis of patients with *** areas under the curve(AUC)values for the 1-,3-,and 5-year survival predictions were 0.618,0.652,and 0.826,*** this risk model,we stratified the samples into high-and low-risk *** KEGG enrichment analysis,we observed that the high-risk group predominantly exhibited enrichment in metabolism-related pathways such as drug and chlorophyll metabolism,whereas the low-risk group demonstrated significant enrichment in cytokine ***,immune landscape analysis revealed noteworthy variations between(PD-L1)expression and risk scores,indicating that o

关键词： Breast Cancer Immunotherapy Prognosis CD8+T cells PD-L1

A NEW CORRENTROPY BASED TDE METHOD UNDER α-STABLE DISTRIBUTION NOISE ENVIRONMENT

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Journal of Electronics(China) 2011年第3期28卷 284-288页

作者： Song Aimin Tong zhijian qiu Tianshuang Faculty of Electronic Information and Electrical Engineering Dalian University of Technology Dalian 115024 China School of Science Dalian Jiaotong University Dalian 116028 China

This paper presents a robust time delay estimation algorithm for the α-Stable noise based on correntropy. Many time delay estimation algorithms derived for impulsive stable noise are based on the theory of Fractional Lower Order Statistics (FLOS). Unlike previously introduced FLOS-type algorithms, the new algorithm is proposed to estimate the time delay by maximizing the generalized correlation function of two observed signals needing neither prior information nor estimation of the numerical value of the stable noise's characteristic exponent. An interval for kernel selection is found for a wide range of characteristic exponent values of α-Stable distribution. Simulations show the proposed algorithm offers superior performance over the existing covariation time delay estimation, least mean p-norm time delay estimation and achieves slightly improved performance than fractional lower order covariance time delay estimation at lower signal to noise ratio when the noise is highly impulsive.

关键词： α-Stable Distribution Correntropy Generalized Correntropy Function (GCF)

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Carleson测度和多项式逼近

数学年刊（A辑） 2007年第2期28卷 159-166页

作者：邱志坚西南财经大学经济数学系成都610074

设G是复平面C上的单连通区域,在研究G上的Carleson测度和多项式在G上的Hardy空间Hq(G)中的稠密性问题时,建立起了两者之间的一种等价关系．用Carleson测度给出了多项式在Hq(G)中稠密的充要条件,也刻画了所有那些使得在其上的Carleson测... 详细信息

设G是复平面C上的单连通区域,在研究G上的Carleson测度和多项式在G上的Hardy空间Hq(G)中的稠密性问题时,建立起了两者之间的一种等价关系．用Carleson测度给出了多项式在Hq(G)中稠密的充要条件,也刻画了所有那些使得在其上的Carleson测度和Carleson不等式等价的单连通区域．

关键词： Carleson测度调和测度 Hardy空间多项式逼近

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考虑碎石桩加固的液化场地桥梁地震风险分析

湖南大学学报（自然科学版） 2022年第7期49卷 178-185页

作者：古泉俞至权邱志坚厦门大学建筑与土木工程学院福建厦门361005

以一座典型的四跨钢筋混凝土连续桥梁为例,建立三个液化场地桩-土-桥梁体系平面应变有限元模型,考虑饱和土体中孔隙水与土颗粒的动力耦合效应,探究碎石桩作为桥梁工程抗液化加固措施的效果.通过构建液化场地桥梁结构的易损性曲线和地震... 详细信息

以一座典型的四跨钢筋混凝土连续桥梁为例,建立三个液化场地桩-土-桥梁体系平面应变有限元模型,考虑饱和土体中孔隙水与土颗粒的动力耦合效应,探究碎石桩作为桥梁工程抗液化加固措施的效果.通过构建液化场地桥梁结构的易损性曲线和地震危险曲线,在概率理论框架下诠释碎石桩加固措施对桩基桥梁地震风险的影响,并对有无碎石桩加固措施的计算结果进行对比分析.结果表明:碎石桩抗液化效果显著,可以有效减少土体的超孔隙水压,进而大幅降低液化场地桥梁的整体侧向变形、破损概率和地震风险.

关键词：砂土液化碎石桩加固桩-土-桥梁结构易损性地震风险性

基于调制比控制的飞轮储能用异步电机闭环发电

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电力系统及其自动化学报 2018年第11期30卷 95-100页

作者：曾程仇志坚上海大学机电工程与自动化学院上海市电站自动化技术重点实验室上海200072

传统的飞轮储能电压控制方法或受电机参数影响较大,或需测量转子转速和定子电流,使得控制系统计算复杂。为此,提出一种基于调制比的异步电机闭环发电控制方法。首先,推导了调制比和直流母线发电电压的数学模型,分析了不同定子角频率下... 详细信息

传统的飞轮储能电压控制方法或受电机参数影响较大,或需测量转子转速和定子电流,使得控制系统计算复杂。为此,提出一种基于调制比的异步电机闭环发电控制方法。首先,推导了调制比和直流母线发电电压的数学模型,分析了不同定子角频率下调制比与发电电压的关系;然后,在此基础上搭建了基于调制比的闭环发电控制系统,并在飞轮储能模拟实验平台上进行了闭环发电实验,实验结果验证了调制比闭环发电控制方法的有效性和正确性。

关键词：飞轮储能电压控制调制比异步发电机