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Contact-pair neighborhood theorem for submanifolds in symplectic pairs

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Frontiers of Mathematics in China 2019年第4期14卷 781-791页

作者： hai-long HER Department of Mathematics Jinan University Guangzhou 510632 China

Let M be a 2n-dimensional smooth manifold associated with the structure of symplectic pair which is a pair of closed 2-forms of constant ranks with complementary kernel foliations. Let Q ■M be a codimension 2 compact submanifold. We show some sufficient and necessary conditions on the existence of the structure of contact pair (α,β) on Q, which is a pair of 1-forms of constant classes whose characteristic foliations are transverse and complementary such that α and β restrict to contact forms on the leaves of the characteristic foliations of β and α, respectively. This is a generalization of the neighborhood theorem for contact-type hypersurfaces in symplectic topology.

关键词： Symplectic pair neighborhood theorem contact pair Liouville vector field

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云多租数据库资源规划调度技术综述

软件学报 2025年第1期36卷 446-468页

作者：刘海龙王硕侯舒峰徐海洋李战怀西北工业大学计算机学院大数据存储与管理工业和信息化部重点实验室(西北工业大学)

云多租数据库具有按需付费、按需扩展、免部署、高可用、自带运维能力、资源共享等诸多优势,可以大大降低用户使用数据库服务的成本.现在越来越多的企业和个人开始在数据库即服务(DaaS)平台托管他们的数据库服务. DaaS平台需要按照用户... 详细信息

云多租数据库具有按需付费、按需扩展、免部署、高可用、自带运维能力、资源共享等诸多优势,可以大大降低用户使用数据库服务的成本.现在越来越多的企业和个人开始在数据库即服务(DaaS)平台托管他们的数据库服务. DaaS平台需要按照用户服务水平协议(SLA)为诸多租户提供服务,同时也需要保障平台收益.但是,由于租户及其负载具有动态性、异构性和竞争性等特点,如何在遵循SLA的同时根据负载自适应规划调度资源同时兼顾平台收益对于DaaS平台来说是一件极具挑战性的工作.针对云多租数据库中比较常见的类型,如关系型数据库,详细分析了当前云多租数据库资源规划调度技术所面临的挑战,提炼了关键科学问题,给出了技术框架,然后从资源规划调度技术、资源预估技术、资源弹性伸缩技术以及数据库资源规划调度工具等4个方面对现有研究工作进行了总结和分析,并且展望了未来的研究方向.

关键词：多租户云数据库资源规划调度资源预估资源弹性伸缩关系数据库云原生多模数据库

Mechanism of Drug Resistance Identified in Human Lung Adenocarcinoma Cell Line SPC-A1 Selected for Resistance to Docetaxel

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Chinese Journal of Cancer Research 2009年第3期21卷 207-216页

作者： hai Sun long-bang Chen Department of Medical Oncology Jinling Hospital Nanjing University School of Medicine Nanjing 210002 China

Objective： To investigate the mechanism of resistance to docetaxel in human lung cancer. Methods： Human lung carcinoma SPC-A1/Docetaxel cells were derived from parental SPC-A1 cells by continuous exposure to increasing concentration of docetaxel. The drug sensitivity was measured by MTT assay in vitro. The cDNA microarray identified a set of differentially expressed genes, and some genes were confirmed by RT-PCR. P-glycoprotein level was measured by flow cytometry analysis. Results： The results of drug sensitivity measured by MTT assay showed that SPC-A1/Docetaxel cells were 13.2-fold resistant to docetaxel and cross-resistant at varying levels to other drugs. The cDNA microarray results identified a set of differentially expressed genes, which showed 428 genes that were up-regulated and 506 genes that were down-regulated in SPC-A1/Docetaxel ceils, and some genes were confirmed by RT-PCR. Flow cytometry analysis suggests expression of P-glycoprotein （P-gp） was more abundant in SPC-A1/Docetaxel cells than in the parental cells and docetaxel selection reduces the apoptotic response. Conclusion： The results suggest that docetaxel selection led to changes in gene expression that contribute to the multidrug resistance phenotype.

关键词： Lung cancer Multidrug resistance Docetaxel cDNA mieroarray

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Ranging-aided relative navigation of multi-platforms

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Control Theory and Technology 2018年第2期16卷 122-132页

作者： hai-long PEI Ruican XIA Key Lab of Autonomous Systems and Networked Control Ministry of Education China Unmanned System Engineering Center of Guangdong Province Guangzhou Guangdong 510640 China School of Automation South China University of Technology Guangzhou Guangdong 510640 China

This paper proposes a relative attitude and distance estimation algorithm based on pairwise range measurements between vehicles as well as inertial measurement of each platform. The solution of Wahba＇s Problem is introduced to compute the relative attitude between multi-platforms with the sampled pairwise ranges, in which the relative distance estimation is derived and the estimation error distributions are analyzed. An extended Kalman filter is designed to fuse the estimated attitude and distance with the inertial measurement of each platform. The relative poses between platforms are determined without any external aided measurement. To show this novelty, a real testbed is constructed by our research lab. And the experiment results are positive.

关键词： Multi-vehicles relative navigation Wahba's Problem pose estimation extended Kalman filter

Towards an improved prediction of soil-freezing characteristic curve based on extreme gradient boosting model

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Geoscience Frontiers 2024年第6期15卷 229-243页

作者： Kai-Qi Li hai-long He Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina College of Natural Resources and Environment Northwest A&F UniversityYangling 712100China Department of Soil Science University of ManitobaWinnipegManitobaR3T 2N2 Canada

As an essential property of frozen soils,change of unfrozen water content(UWC)with temperature,namely soil-freezing characteristic curve(SFCC),plays significant roles in numerous physical,hydraulic and mechanical processes in cold regions,including the heat and water transfer within soils and at the land–atmosphere interface,frost heave and thaw settlement,as well as the simulation of coupled thermo-hydro-mechanical *** various models have been proposed to estimate SFCC,their applicability remains limited due to their derivation from specific soil types,soil treatments,and test ***,this study proposes a novel data-driven model to predict the SFCC using an extreme Gradient Boosting(XGBoost)model.A systematic database for SFCC of frozen soils compiled from extensive experimental investigations via various testing methods was utilized to train the XGBoost *** predicted soil freezing characteristic curves(SFCC,UWC as a function of temperature)from the well-trained XGBoost model were compared with original experimental data and three conventional *** results demonstrate the superior performance of the proposed XGBoost model over the traditional models in predicting *** study provides valuable insights for future investigations regarding the SFCC of frozen soils.

关键词： Soil freezing characteristic curve(SFCC) Soil temperature Unfrozen water content XGBoost model Machine Learning Feature importance

Estimation of velocity potential of water waves using a Luenberger-like observer

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Science China(Information Sciences) 2020年第12期63卷 139-152页

作者： Yang YU hai-long PEI Cheng-Zhong XU Key Laboratory of Autonomous Systems and Networked Control Ministry of EducationSouth China University of Technology Unmanned Aerial Vehicle Systems Engineering Technology Research Center of Guangzhou South China University of Technology LAGEPP University Claude Bernard-Lyon 1

We propose a Luenberger-like observer for a water wave system. The water wave dynamics are assumed to be governed by the linearized water wave equation(LWWE). Our proposed observer estimates the velocity potential of water waves by measuring only the surface wave elevation. The information of the water-wave velocity field is then extracted from the gradient of the velocity potential. It is shown that the estimation error of the observer converges exponentially to zero as time tends to infinity. Furthermore,we numerically solve the LWWE and observer equation by the finite difference method. The efficiency of our proposed numerical scheme and the performance of the observer are validated by numerical simulation results.

关键词： linearized water wave equation LWWE Luenberger-like observer numerical simulations

Axial coordination regulation of MOF-based single-atom Ni catalysts by halogen atoms for enhanced CO_(2) electroreduction

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Nano Research 2022年第12期15卷 10063-10069页

作者： Jia-Xin Peng Weijie Yang Zhenhe Jia long Jiao hai-long Jiang Department of Chemistry University of Science and Technology of ChinaHefei230026China Department of Power Engineering School of EnergyPower and Mechanical EngineeringNorth China Electric Power UniversityBaoding071003China

Single-atom catalysts(SACs),with the utmost atom utilization,have attracted extensive interests for various catalytic *** coordination environment of SACs has been recognized to play a vital role in catalysis while their precise regulation at atomic level remains an immense ***,a post metal halide modification(PMHM)strategy has been developed to construct Ni-N4 sites with axially coordinated halogen atoms,named Ni1-N-C(X)(X=CI,Br,and I),on pre-synthetic nitrogen-doped carbon derived from metal-organic *** axial halogen atoms with distinct electronegativity can break the symmetric charge distribution of planar Ni-N4 sites and regulate the electronic states of central Ni atoms in Ni1-N-C(X)(X=Cl,Br,and I).Significantly,the Ni1-N-C(CI)catalyst,decorated with the most electronegative Cl atoms,exhibits Faradaic efficiency of CO up to 94.7%in electrocatalytic CO_(2) reduction,outperforming Ni1-N-C(Br)and Ni1-N-C(I)***,Ni1-N-C(CI)also presents superb performance in Zn-CO_(2) battery with ultrahigh CO selectivity and great *** calculations reveal that the axially coordinated Cl atom remarkably facilitates*COOH intermediate formation on single-atom Ni sites,thereby boosting the CO_(2) reduction performance of Ni1-N-C(CI).This work offers a facile strategy to tailor the axial coordination environments of SACs at atomic level and manifests the crucial role of axial coordination microenvironments in catalysis.

关键词： metal-organic frameworks single-atom catalysts CO_(2)electroreduction axial coordination environment

An Improved Result for Positive Measure Reducibility of Quasi-periodic Linear Systems

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Acta Mathematica Sinica,English Series 2006年第1期22卷 77-86页

作者： hai long HE Jian Gong YOU Department of Mathcmatics Nanjing University Nanjing 210093 P. R. China

In this paper, by the KAM method, under weaker small denominator conditions and nondegeneracy conditions, we prove a positive measure reducibility for quasi-periodic linear systems close to constant： X = （A（λ）＋ F（ψ, λ））X, ψ=ωwhere the parameter λ∈ （a, b）, w is a fixed Diophantine vector, which is a generalization of jorba ＆ Simo＇s positive measure reducibility result.

关键词： Quasi-periodic Reducibility KAM Non-degeneracy

Microstructure-mechanical property relationship in Ti-Mo microalloyed steel with random and interphase precipitates

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Journal of Iron and Steel Research International 2019年第8期26卷 838-845页

作者： hai-long Yi Lu-ran Zhang Rui-hai Duan Xin-zeng Liang State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110819 Liaoning China

The relationship between microstructure and mechanical properties of Ti-Mo microalloyed steels composed of ferrite and bainite with nanometer-sized carbides and isothermally transformed at different temperatures and time was systematically investigated by tensile test, hardness test, and transmission electron microscopy. Ferrite formed at high temperatures exhibited both planar/curved sheet-like dispersions of interphase precipitates and random dispersion precipitates, with the interphase precipitates being the dominant morphology. In contrast, bainite formed at low temperatures exhibited only random dispersion precipitates. Furthermore, random dispersion precipitates and interphase precipitates were observed within the same ferrite grains. The mechanical properties of the ferrite specimen were superior to those of the bainite specimen. The stress-strain curves of both specimens indicated continuous yielding, high strength, and sufficient tensile elongation. The strengthening of the ferrite specimen was attributed to grain size strengthening, dislocation strengthening, and precipitation hardening, and the degree of precipitation strengthening was approximately 300 MPa.

关键词： Mechanical property Interphase precipitate Dispersion precipitate Precipitation strengthening Ti-Mo microalloyed stee