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Existence of Nontrivial Solutions for p-Laplacian-like Equations

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Acta Mathematicae Applicatae Sinica 2011年第3期27卷 393-406页

作者： Zhou-xin li Yao-tian Shen Department of Mathematics South China University of Technology Guangzhou 510640 China

In this paper, we study the p-Laplacian-like equations involving Hardy potential or involving critical exponent and prove the existence of one or infinitely many nontrivial solutions. The results of the equations disc... 详细信息

关键词： p-Laplacian-like equation hardy potential critical exponent

民族地区社会组织铸牢中华民族共同体意识:实践、困境与路径

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阴山学刊 2024年第3期37卷 18-27页

作者：常进锋李心恬西北民族大学中华民族共同体学院甘肃兰州730124

民族地区社会组织在铸牢中华民族共同体意识中扮演着重要角色。为民族地区铸牢中华民族共同体意识,社会组织在经济、文化、社会、生态等层面积极开展实践探索。但是社会组织在参与民族地区铸牢中华民族共同体意识中还存在章程规定缺失... 详细信息

民族地区社会组织在铸牢中华民族共同体意识中扮演着重要角色。为民族地区铸牢中华民族共同体意识,社会组织在经济、文化、社会、生态等层面积极开展实践探索。但是社会组织在参与民族地区铸牢中华民族共同体意识中还存在章程规定缺失、社会组织筹资困难、民众认知度不高等困境,亟须社会组织继续坚持党的领导,以民族工作为引导,将铸牢中华民族共同体意识纳入组织章程,强化成员铸牢中华民族共同体意识的专业能力,培育民族地区内生发展动力,以经济发展带动民族团结,推进新时代民族地区社会组织铸牢中华民族共同体意识。

关键词：民族地区社会组织铸牢中华民族共同体意识新内源性发展理念

Bifurcations of limit Cycles in A Perturbed Quintic Hamiltonian System with Six Double Homoclinic Loops

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Acta Mathematicae Applicatae Sinica 2008年第2期24卷 313-328页

作者： Yong-xi Gao Yu-hai Wu li-xin tian Department of Mathematics Jiang Su University Zhenjiang 212013 China

This paper concerns with the number and distributions of limit cycles of a quintic subject to a seven-degree perturbation. With the aid of numeric integral computation provided by Mathematica 4.1, at least 45 limit cycles are found in the above system by applying the method of double homoclinic loops bifurcation, Hopf bifurcation and qualitative analysis. The four configurations of 45 limit cycles of the system are also shown. The results obtained are useful to the study of the weakened 16th Hilbert Problem.

关键词： limit cycles the Hilbert's 16th problem the double homoclinic loops stability Poincare-Bendixsontheorem

Bifurcations of limit Cycles in a Z_4-Equivariant Quintic Planar Vector Field

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Acta Mathematica Sinica,English Series 2010年第4期26卷 779-798页

作者： Yu Hai WU Xue Di WANG li xin tian Department of Mathematics Jiangsu University Zhenjiang 212013 P. R. China

In this paper, a Z4-equivariant quintic planar vector field is studied. The Hopf bifurcation method and polycycle bifurcation method are combined to study the limit cycles bifurcated from the compounded cycle with 4 hyperbolic saddle points. It is found that this special quintic planar polynomial system has at least four large limit cycles which surround all singular points. By applying the double homoclinic loops bifurcation method and Hopf bifurcation method, we conclude that 28 limit cycles with two different configurations exist in this special planar polynomial system. The results acquired in this paper are useful for studying the weakened 16th Hilbert＇s Problem.

关键词： compounded cycle double homoclinic loops stability bifurcation limit cycles distribution of limit cycles

On the limit cycles of a quintic planar vector field

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Science China Mathematics 2007年第7期50卷 925-940页

作者： Yu-hai WU li-xin tian Mao-an HAN Department of Mathematics Jiangsu UniversityZhenjiang 212013China Department of Mathematics Shanghai Normal UniversityShanghai 200234China

This paper concerns the number and distributions of limit cycles in a Z 2-equivariant quintic planar vector field. 25 limit cycles are found in this special planar polynomial system and four different configurations of these limit cycles are also given by using the methods of the bifurcation theory and the qualitative analysis of the differential equation. It can be concluded that H(5) ? 25 = 52, where H(5) is the Hilbert number for quintic polynomial systems. The results obtained are useful to study the weakened 16th Hilbert problem.

关键词： double homoclinic loop Melnikov function stability bifurcation limit cycles configuration 34C07 34C23 34C37 37G15

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中医儿科临床优势病种遴选研究

世界中西医结合杂志 2024年第6期19卷 1173-1176页

作者：宋兴磊刘应科李天鑫高嘉黎明莉任昕昕王秋莉杨晔张辰北京中医药大学东直门医院北京100700 北京市和平里医院北京100013

目的调查中医儿科优势病种的认识、范畴及临床治疗认可度,为构建中医儿科优势病种体系提供支撑。方法采用同行评议法,参照文献及专家意见设计调查问卷,通过线上方式发放问卷,对回收的问卷进行统计分析。结果研究收回有效答卷684份,确定... 详细信息

目的调查中医儿科优势病种的认识、范畴及临床治疗认可度,为构建中医儿科优势病种体系提供支撑。方法采用同行评议法,参照文献及专家意见设计调查问卷,通过线上方式发放问卷,对回收的问卷进行统计分析。结果研究收回有效答卷684份,确定中医儿科优势病种具备安、效、特、廉、捷的五项优势,并遴选出23种优势病种,在临床中中西医结合治疗方式具有较好认可度。结论目前医务工作者对中西医结合治疗的认可度较高,但对中医儿科优势病种的认识仍存不足,应当制定、实践、推广中医儿科优势病种的方法和标准。

关键词：中医儿科优势病种调查报告

Influence of friction-lubrication characteristics varying with rolling speed on instability of chatter and slip in cold tandem rolling process

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Journal of Iron and Steel Research International 2024年第4期31卷 894-908页

作者： Yan-li xin Zhi-ying Gao Bo tian Qing-dong Zhang School of Mechanical Engineering University of Science and Technology BeijingBeijing 100083China

In the high-speed cold tandem rolling process of thin plate,chatter or slip instability gives rise to the deterioration of equipment and product *** instability behavior is closely related to interfacial friction-lubrication con-dition which is generally characterized by the friction ***,with higher and higher speed requirements,the commonly used model of friction coefficient is no longer applicable and accurate.A novel approach is suggested to calculate the speed-dependent friction coefficient,in which the viscosity-pressure-temperature effects of the lubricant,surface roughness states of work rolls and rolled piece are comprehensively involved and the mixed flm lubrication theory is ***,the influences of friction coefficient on the instability of slip and chatter are investigated for a five-stand cold tandem rolling *** one side,the critical friction coefficient for each stand is determined by calculating the corresponding slip factor;on the other hand,the friction coefficient varying with rolling speed is combined with the model of theoretical critical rolling speed presented under constant friction coefficient,so that the speed threshold is ***,the stable and unstable regions corresponding to the rear three stands are individually discussed,and the technical strategies are proposed to suppress both slip and chatter frequently occurring in the actual rolling process.

关键词： Cold tandem rolling:Oil film thickness Speed-dependent friction coefficient-Slip:Chatter

Development characteristics and controlling factor analysis of the Neogene Minghuazhen Formation shallow water delta in Huanghekou area, Bohai offshore basin

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Journal of Palaeogeography 2019年第3期8卷 251-269页

作者： li-xin tian Hao liu Cheng-Min Niu Xiao-Feng Du Bo Yang Xiao-Dong Lan Dan-Lei Chen Shenzhen Branch of China National Offshore Oil Corporation Shenzhen People's Republic of China School of Ocean Sciences China University of Geosciences (Beijing) Beijing 100083 People's Republic of China Exploration & Exploitation Research Institute Tianjin Branch of China National Offshore Oil Corporation Tianjin People's Republic of China

Based on a combination of high resolution 3-D seismic, drilling and well logging and core data, this study focuses on describing the depositional features of the Neogene Minghuazhen Formation shallow water delta in Huanghekou area(HHKA), Bohai offshore basin and discussing the evolution and controlling factors of shallow water delta sandbody. An obvious meandering fluvial delta system developed in sequence 1(SQ1) of the Neogene in HHKA with thinner sandbody of distributary channels and poor development of mouth bar. The sequence texture obviously influences the vertical development and stacking pattern of sandbodies and controls the distribution of sandbodies in plain view as well. In shallow water lacustrine basins, relative topographic height difference leads to change of distribution of accommodation space, and sandbodies of distributary channels usually develop well in local low-lying areas where accommodation space increases. The delta is dominated by distributary channel sandbodies during the early period of base level rising. Sandbodies contact with each other in a lateral stacking pattern and are characterized by a fan shape in plain view. Distributary channels gradually narrow and tend to shift during the mid-late-period of base level rising, while the sandbodies are characterized by a net shape in plain view. During the period of base level slow falling, the multistory/multilateral channel sandbodies dominated the inner front of shallow-water delta and the delta sand dispersal distributes as a lobe shape.

关键词： The Neogene Minghuazhen Formation Huanghekou area Bohai offshore basin Shallow water delta Micro-palaeogeomorphology Base level Sandbody stacking pattern

Research on denoising of joint detection signal of water quality with multi-parameter based on IEEMD

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Optoelectronics Letters 2024年第2期20卷 107-115页

作者： li Wen li Dejian MA Yongyue tian Wang WEN xin li Jie Institute of Mechanical and Electrical Engineering North China University of TechnologyBeijing 100144China1

An improved ensemble empirical mode decomposition(IEEMD) is suggested to process water quality spectral signals in order to address the issue that noise interference makes it difficult to extract and evaluate water quality spectral *** algorithm effectively solves the problems of modal mixing,poor reconstruction accuracy in the empirical mode decomposition(EMD),and a large amount of calculation in the ensemble empirical mode decomposition(EEMD).Based on EEMD,IEEMD firstly preprocesses the original water quality spectral signals,then performs Savitzky-Golay(S-G) smoothing on the decomposed effective intrinsic mode function(IMF) components,and finally reconstructs them to obtain the denoised *** sample data at different concentrations can be accurately analyzed based on the noise-reduced spectral *** this paper,three water quality parameters are used as research objects:benzene(C_(6)H_(6)),benzo(b)fluoranthene(C_(20)H_(12)),and chemical oxygen demand(COD).The original water quality multi-parameter(C_(6)H_(6),C_(20)H_(12),COD) spectral signals were subjected to denoising based on the IEEMD and the water quality multi-parameter joint detection *** signal-to-noise ratio(SNR) and the correlation coefficient(R^(2)) of the fitted curves obtained from the processing of the IEEMD were compared and analyzed with those obtained from the processing of the EMD and the *** experimental results show that the SNR of the spectral signals and the R^(2) of the fitting curve in three water quality parameters have been significantly ***,the IEEMD effectively improves the phenomenon of modal mixing,reduces the amount of calculation,improves the reconstruction accuracy,and provides an important guarantee for the effective extraction of multi-parameter spectral signals of water quality.

关键词： signal parameter noise