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Non-Lie Symmetry Groups and New Exact Solutions to the (2 + 1)-Dimensional Broer-Kaup System

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Advances in Pure Mathematics 2013年第1期3卷 149-152页

作者： Bin Zheng xiqiang liu School of Mathematics and Physics Southwest University of Science and Technology Mianyang China School of Mathematics Sciences Liaocheng University Liaocheng China

For the (2 + 1)-dimensional Broer-Kaup system, we study the corresponding Lie symmetry groups, and obtain the symmetry group theorem and the Backlund transformation formula of solutions finding. At the same time, we find some new exact solutions of the (2 + 1)-dimensional Broer-Kaup system and extend the results in the papers [1-4].

关键词： Broer-Kaup System Lie Symmetry Group Exact Solution Backlund Transform

Single-cell transcriptomic analysis uncovers the origin and intratumoral heterogeneity of parotid pleomorphic adenoma

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International Journal of Oral Science 2023年第3期15卷 476-488页

作者： Xiuyun Xu Jiaxiang Xie Rongsong Ling Shengqi Ouyang Gan Xiong Yanwen Lu Bokai Yun Ming Zhang Wenjin Wang xiqiang liu Demeng Chen Cheng Wang Hospital of Stomatology Sun Yat-sen UniversityGuangzhouChina Guangdong Provincial Key Laboratory of Stomatology Sun Yat-sen UniversityGuangzhouChina Guanghua School of Stomatology Sun Yat-sen UniversityGuangzhouChina Institute for Advanced Study Shenzhen UniversityShenzhenChina Department of Oral and Maxillofacial Surgery Nanfang HospitalSouthern Medical UniversityGuangzhouChina Center for Translational Medicine The First Affiliated HospitalSun Yat-sen UniversityGuangzhouChina

Pleomorphic adenoma(PA)is the most common benign tumour in the salivary gland and has high morphological ***,the origin and intratumoral heterogeneity of PA are largely ***,we constructed a comprehensive atlas of PA at single-cell resolution and showed that PA exhibited five tumour subpopulations,three recapitulating the epithelial states of the normal parotid gland,and two PA-specific epithelial cell(PASE)populations unique to ***,six subgroups of PASE cells were identified,which varied in epithelium,bone,immune,metabolism,stemness and cell cycle ***,we revealed that CD36+myoepithelial cells were the tumour-initiating cells(TICs)in PA,and were dominated by the PI3K-AKT *** the PI3K-AKT pathway significantly inhibited CD36+myoepithelial cell-derived tumour spheres and the growth of PA *** results provide new insights into the diversity and origin of PA,offering an important clinical implication for targeting the PI3K-AKT signalling pathway in PA treatment.

关键词： CD36 metabolism adenoma

Study on Correlation and Quantiative Error Estimation Method Among the Splitting Shear Wave Identification Methods

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Earthquake Research in China 2000年第3期14卷 53-62页

作者： liu xiqiang Zhou Huilan Li Hong Gai Dianguang Seismological Bureau of Shandong Province Jinan 250014 China Graduate School University of Science and Technology of China Beijing 100039 China

Based on the propagation characteristics of shear wave in the anisotropic layers,thecorrelation among several splitting shear-wave identification methods hasbeen *** puts forward the method estimating splitting shear-wave phases and its reliability byusing of the assumption that variance of noise and useful signal data obey *** check the validity of new method,the identification results and errorestimation corresponding to 95% confidence level by analyzing simulation signals have beengiven.

关键词： Anisotropy Shear-wave splitting Identification methods Correlation Error estimation

The Rhythm of Earthquake Activity and an Analysis on the Earthquake Tendency of the World, the Chinese Continent and North China

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Earthquake Research in China 2005年第2期19卷 181-191页

作者： liu xiqiang Lin Huaicun Huang Yun Li Hong Earthquake Administration of Shandong Province Jinan 250014 China Earthquake Administration of Jiangsu Province Nanjing 210014 China

Based on the Morlet complex wavelet transformation,the authors put forward a kind of new method for distinguishing periods of seismic activity and quietude and a new physical thought on the time-dependent wavelet accumulation energy spectrum with periods, the time-frequency distribution of wavelet vibration period spectrum and period-specific wavelet vibration spectrum. By applying the above methods to a time series which is composed of earthquake accumulation energy per year for the world, the Chinese continent and North China, respectively, we obtained some new information about the rhythm of shallow earthquake activity. Considering the historic earthquakes and the rhythm characteristics of current strong earthquake activity, the earthquake tendency in the next years is discussed.

关键词： Morlet complex wavelet transformation Strong earthquake activity rhythm Timedependent characteristics Earthquake tendency prediction

Current Earthquake Early Warning Technology and Its Development in China

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Earthquake Research in China 2013年第2期27卷 144-153页

作者： Yin Haitao liu xiqiang Li Jie Xu Changpeng Earthquake Administration of Shandong Province State Key Laboratory of Earthquake Dynamics Institute of GeologyCEA

Earthquake Early Warning ( EEW) has come to attention,as earthquake prediction is still unreliable. The paper comprehensively illustrates the research status and important issues of EEW from the aspects of concept,composition and method. By analyzing the status of EEW in China,we find that the essential requirements have been met for building earthquake early warning systems in the country in terms of government and social needs, network construction and basic research. The technical difficulties and non-technical challenges in implementing EEW in China are evaluated, and some suggestions are proposed regarding the relevant legal measures,public education and protection against earthquake disasters. so as to bring into full play the role of the EEW system in earthquake disaster prevention and reduction.

关键词： Earthquake Early Warning Seismic wave Magnitude estimation Development

Relocation of Earthquakes in Shandong and Its Neighboring Areas,China and Its Relationship with Active Tectonics

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Earthquake Research in China 2013年第4期27卷 512-526页

作者： Li Xia liu xiqiang Li Yajun Dong Xiaona Zhang Huifeng Earthquake Administration of Shandong Province

Earthquakes taking place from 1975 to 2010 in and around Shandong Province are relocated using double-difference(HypoDD)and Hypoinvers 2000(Hypo2000)methods,after correction of the onset times of seismic *** results show that the relocated seismicity is clearly associated with regional tectonics in space,and is also in agreement with the existence of deep faults imaged by wide-angle and deep seismic reflection profiling;most of the focal depths are in the range of 5～25km,and there are clearly two predominant depths:10km and 16km,which are inferred to be on the bottom of the upper crust and in the middle crust,*** pattern of seismic activity indicates that moderate and strong earthquakes are likely to occur in the brittle-ductile transition zone between the upper and the lower crust,as the outcome of the deep tectonic dynamic process and the movement and deformation of faults in the upper and shallow crust under the regional stress field.

关键词： The double-difference algorithm Seismotectonics Focal depth Predominantdepth of earthquakes Brittle-ductile transition

山东乳山震群剪切波分裂参数的时间演化特征分析

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地震学报 2016年第2期38卷 220-231页

作者：苗庆杰刘希强山东省地震局中国济南250102

2013年10月1日山东乳山发生M_L3.8地震后,该地区的地震活动呈现出小震群特征,且持续至今,其中2014—2015年先后发生了4次M_L4.1—5.0显著性地震,造成了较大的社会影响.本文利用山东数字地震台网中乳山台记录的地震波形资料,测定了来自... 详细信息

2013年10月1日山东乳山发生M_L3.8地震后,该地区的地震活动呈现出小震群特征,且持续至今,其中2014—2015年先后发生了4次M_L4.1—5.0显著性地震,造成了较大的社会影响.本文利用山东数字地震台网中乳山台记录的地震波形资料,测定了来自乳山震群中224次小地震的剪切波分裂参数.研究结果表明:快剪切波的偏振优势方向与山东半岛地区的主压应力方向基本一致;剪切波分裂时间延迟在这4次显著性地震发生前后均产生明显的变化,分裂时间延迟平均在震前1个月左右开始出现升高异常,在震前约12天出现下降异常变化.这些特征均可作为利用应力进行地震预测的前兆指标.

关键词：乳山震群应力积累剪切波分裂时间延迟

Discussion on the Measurement Method for the Coda Wave Quality Factor

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Earthquake Research in China 2009年第4期23卷 420-433页

作者： liu xiqiang Shi Yuyan Qu Junhao Li Hong Li Bo Zhang Kun Earthquake Administration of Shandong Province Jinan 250014 China

The Quality factor is the parameter that can be used to describe the energy attenuation on seismic wave. In theory, we can obtain the relationship between the change of the coda wave quality factor with time and the strong earthquake preparation process on the basis of the quality factor of a coda wave in a same ray path. However, in reality the coda wave quality factor measured by different seismic coda waves corresponds to different seismic wave ray paths. The change of the quality factor with time is related to non-elastic characteristics of the medium and the volume of scattering ellipsoid constrained by scattered wave phase fronts, besides the change of regional stress field. This paper discusses the relationship between quality factor, epicenter distance and different lapse time, and then discusses the relationship between quality factor and frequency. Furthermore the determination method of the coda wave quality factor is put forward. The improved determination method of the quality factor, which removes the influence of different earthquakes or propagation depth of scattered waves, may increase measurement precision, thus information pertaining to abnormal changes in quality factor and the relationship between the quality factor and earthquake preparation process can be acquired.

关键词： Quality factor Coda wave Measurement method Discussion Application

The Quantitative Identification of Regional Mine and Natural Earthquakes and Its Application

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Earthquake Research in China 2005年第3期19卷 269-281页

作者： liu xiqiang Du Yihe Xu Bo Li Hong Shen Ping Zhang Ping Earthquake Administration of Shandong Province Jinan 250014 China Earthquake Administration of Jinan City Jinan 250001. China Institute of Geophysics China Earthquake Administration Beijing 100081 China Earthquake Administration of Liaoning Province Shenyang 100031 China

Based on the Morlet wavelet transform and digital data from the Fushun and Beizhen seismic stations, Liaoning Province, we put forward a new method in the paper, called time-frequency energy attenuation factor （α-value）. The characteristics of the α-value and its variation with magnitude of natural and mine earthquakes are studied, and the statistic relations between the α-value and specific earthquake magnitude are obtained. From the results, some conclusions can be drawn as follows：（1） in general, the α-values of mine and natural earthquakes of the same intensity have obvious difference and the ranges of their variation do not overlap each other; （2） the α-value decreases with the increase of earthquake magnitude, and the α-value of mine earthquake decreases faster than that of natural earthquake; （3） based on the earthquake magnitude and on the relations between the α-value and earthquake magnitude, we can distinguish the mine earthquakes from the natural ones; （4） the difference in focal mechanism of mine and natural earthquakes would be the main cause for obvious difference of the α-value; （5） the α-value variation is relatively steady for mine and natural earthquakes that occur in the same region, but it has obvious regional difference. The above results are of inspirational meaning for the study of abnormal change of the α-value before strong earthquakes.

关键词： Morlet wavelet Time-frequency energy attenuation factor The identification of mine and natural earthquakes Regional characteristics