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Relative energy zero ratio-based approach for identifying pulse-like ground motions

Earthquake Engineering and Engineering Vibration 2020年第1期19卷 1-16页

作者： Liu Ping Li Ning Ma Hua xie lili Zhou Baofeng School of Civil Engineering/Key Laboratory of Coast Civil Structure Safety Ministry of Education(Tianjin University)Tianjin 300072China Ren’ai College Tianjin UniversityTianjin 301636China Key Laboratory of Earthquake Engineering Simulation and Seismic Resilience of China Earthquake Administration(Tianjin University) Tianjin 300350China Key Laboratory of Engineering and Structural Retrofi t Beijing University of TechnologyBeijing 100124China Key Laboratory of Earthquake Engineering and Engineering Vibration Institute of Engineering MechanicsChina Earthquake AdministrationHarbin 150080China

Pulse-like ground motions are capable of inflicting significant damage to structures. Efficient classification of pulse-like ground motion is of great importance when performing the seismic assessment in near-fault regions. In this study, a new method for identifying the velocity pulses is proposed, based on different trends of two parameters: the short-time energy and the short-time zero crossing rate of a ground motion record. A new pulse indicator, the relative energy zero ratio(REZR), is defined to qualitatively identify pulse-like features. The threshold for pulse-like ground motions is derived and compared with two other identification methods through statistical analysis. The proposed procedure not only shows good accuracy and efficiency when identifying pulse-like ground motions but also exhibits good performance for classifying records with high-frequency noise and discontinuous pulses. The REZR method does not require a waveform formula to express and fit the potential velocity pulses;it is a purely signal-based classification method. Finally, the proposed procedure is used to evaluate the contribution of pulse-like motions to the total input energy of a seismic record, which dramatically increases the seismic damage potential.

关键词： pulse-like ground motion velocity pulse relative energy zero-crossing ratio short-time input energy shorttime zero crossing rate

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Strong motion characteristics of the M_w 6.6 Lushan earthquake,Sichuan,China——an insight into the spatial difference of a typical thrust fault earthquake

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Earthquake Engineering and Engineering Vibration 2015年第2期14卷 203-216页

作者： Hu Jinjun Zhang Wenbo xie lili Zhang Qi Jiang Zhijun Key Laboratory of Earthquake Engineering and Engineering Vibration Institute of Engineering Mechanics China Earthquake Administration College of Earth Science University of Chinese Academy of Science School of Civil Engineering Harbin Institute of Technology

Near-field strong ground motions are useful for engineering seismology studies and seismic design, but dense observation networks of damaging earthquakes are still rare. In this study, based on the strong-motion data from the M w 6.6 Lushan earthquake, the ground motion parameters in different spatial regions are systematically analyzed, and the contributions from different effects, like the hanging-wall effect, directivity effect, and attenuation effect are separated to the extent possible. Different engineering parameters from the observed ground motions are compared with the local design response spectra and a new attenuation relation of Western China. General results indicate that the high frequency ground motion, like the peak ground acceleration, on two sides of the fault plane is sensitive to the hanging-wall effect, whereas the low frequency ground motion, like the long period spectral acceleration, in the rupture propagation direction is affected by the directivity effect. Moreover, although the M w 6.6 Lushan earthquake is not a large magnitude event, the spatial difference of ground motion is still obvious; thus, for a thrust faulting earthquake, in addition to the hanging effect, the directivity effect should also be considered.

关键词： Lushan earthquake near-fi eld ground motion direct

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A sophisticated simulation for the fracture behavior of concrete material using XFEM

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Earthquake Engineering and Engineering Vibration 2017年第4期16卷 859-881页

作者： Zhai Changhai Wang Xiaomin Kong Jingchang Li Shuang xie lili School of Civil Engineering Harbin Institute of TechnologyHarbin 150090China Key Lab of Structures Dynamic Behavior and Control(Harbin Institute of Technology) Ministry of EducationHeilongjiangHarbin 150090China Institute of Engineering Mechanics China Earthquake AdministrationHarbin 150080China

The development of a powerful numerical model to simulate the fracture behavior of concrete material has long been one of the dominant research areas in earthquake engineering. A reliable model should be able to adequately represent the discontinuous characteristics of cracks and simulate various failure behaviors under complicated loading conditions. In this paper, a numerical formulation, which incorporates a sophisticated rigid-plastic interface constitutive model coupling cohesion softening, contact, friction and shear dilatation into the XFEM, is proposed to describe various crack behaviors of concrete material. An effective numerical integration scheme for accurately assembling the contribution to the weak form on both sides of the discontinuity is introduced. The effectiveness of the proposed method has been assessed by simulating several well-known experimental tests. It is concluded that the numerical method can successfully capture the crack paths and accurately predict the fracture behavior of concrete structures. The influence ofmode-Ⅱ parameters on the mixed-mode fracture behavior is further investigated to better determine these parameters.

关键词： fracture behavior concrete material earthquake engineering interface constitutive model XFEM

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Experimental study on the interrelation of multiple mechanical parameters in overburden rock caving process during coal mining in longwall panel

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International Journal of Coal Science & Technology 2023年第4期10卷 265-289页

作者： Daixin Deng Hongwei Wang lili xie Zeliang Wang Jiaqi Song School of Mechanics and Civil Engineering China University of Mining and TechnologyBeijing 100083China State Key Laboratory of Coal Resources and Safe Mining China University of Mining and TechnologyBeijing 100083China

In order to comprehend the dynamic disaster mechanism induced by overburden rock caving during the advancement of a coal mining face, a physical simulation model is constructed basing on the geological condition of the 21221 mining face at Qianqiu coal mine in Henan Province, China. This study established, a comprehensive monitoring system to investigate the interrelations and evolutionary characteristics among multiple mechanical parameters, including mining-induced stress, displacement, temperature, and acoustic emission events during overburden rock caving. It is suggested that, despite the uniformity of the overburden rock caving interval, the main characteristic of overburden rock lies in its uneven caving strength. The mining-induced stress exhibits a reasonable interrelation with the displacement, temperature, and acoustic emission events of the rock strata. With the advancement of the coal seam, the mining-induced stress undergoes four successive stages: gentle stability, gradual accumulation, high-level mutation, and a return to stability. The variations in other mechanical parameters does not synchronize with the signifcant changes in mining-induced stress. Before the collapse of overburden rock occurs, rock strata temperature increment decreases and the acoustic emission ringing counts surges with the increase of rock strata displacement and mining-induced stress. Therefore, the collaborative characteristics of mining-induced stress, displacement, temperature, and acoustic emission ringing counts can be identifed as the precursor information or overburden rock caving. These results are in good consistent with on-site situation in the coal mine.

关键词： Overburden rock caving Multiple mechanical parameters Interrelation characterization Precursor information

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Hysteretic energy prediction method for mainshock-aftershock sequences

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Earthquake Engineering and Engineering Vibration 2018年第2期17卷 277-291页

作者： Zhai Changhai Ji Duofa Wen Weiping Li Cuihua Lei Weidong xie lili Key Lab of Structures Dynamic Behavior and Control(Harbin Institute of Technology) Ministry of EducationHeilongjiangHarbin 150090China School of Civil Engineering Harbin Institute of TechnologyHarbin 150090China Shenzhen Graduate School Harbin Institute of Technology Shenzhen 518055China Institute of Engineering Mechanics China Earthquake AdministrationHarbin 150080China

Structures located in seismically active regions may be subjected to mainshock-aftershock（MSAS）*** study selected two kinds of MSAS sequences,with one aftershock and two aftershocks,*** aftershocksThe MSAS sequence with one aftershock exhibited a 10%to 30%hysteretic energy increase,whereas the MSAS sequence with two aftershocks presented a 20%to 40%hysteretic energy ***,a hysteretic energy prediction equation is proposed as a function of the vibration period,ductility value,and damping ratio to estimate hysteretic energy for mainshockaftershock sequences.

关键词： hysteretic energy mainshock-aftershock sequences SDOF system relative intensity prediction equation

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Fetal umbilical vein transplantation for the repair of middle cerebral artery injury

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Neural Regeneration Research 2013年第34期8卷 3249-3254页

作者： Xuhui Hou Yi Yuan Jian Yin Songbai Yang lili xie Shiji Wang Department of Vascular Surgery China-Japan Friendship Hospital of Jilin University Department of Critical Care Medicine First Hospital of Jilin University

It is necessary to investigate the longitudinal tensile mechanical characteristics of the middle cere- bral artery and the fetal umbilical vein prior to applying fetal umbilical vein transplantation for repair of injured middle cerebral artery. Fifteen fresh fetal umbilical vein specimens and 15 normal human fresh cadaver middle cerebral artery specimens were collected for longitudinal tensile testing at the speed of 0.5 mm/min and at normal human temperature. The results showed that under 16.0 kPa physiological stress, the strain value of fetal umbilical vein specimens was larger, while the maximal stress and elastic modulus values were less than those of middle cerebral artery specimens. Our findings indicate that fetal umbilical vein has good elastic properties and the stress-strain curve of the fetal umbilical vein is similar to that of the middle cerebral artery. Fetal umbilical vein transplan- tation can, therefore, potentially repair the injured middle cerebral artery.

关键词： neural regeneration middle cerebral artery fetal umbilical vein tension stress strain elasticmodulus biomechanics transplantation repair neuroregeneration

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角膜塑形镜与RLRL联合应用在青少年进展性近视中的治疗效果

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眼科新进展 2024年第8期44卷 627-631页

作者：刘颖谢丽丽郭彦芳安通尹丹李勇梁冬梅衡水市人民医院眼科河北省衡水市053000

目的探究角膜塑形镜联合重复低能量红光照射(RLRL)在青少年进展性近视中的治疗效果。方法选取2020年3月至2022年9月我院收治的中低度青少年进展性近视患者106例(212眼),随机分为观察组(57例114眼)和对照组(49例98眼)。观察组患者行角膜... 详细信息

目的探究角膜塑形镜联合重复低能量红光照射(RLRL)在青少年进展性近视中的治疗效果。方法选取2020年3月至2022年9月我院收治的中低度青少年进展性近视患者106例(212眼),随机分为观察组(57例114眼)和对照组(49例98眼)。观察组患者行角膜塑形镜联合RLRL治疗,对照组患者行角膜塑形镜治疗。随访12个月,比较两组患者治疗前后不同时间点裸眼视力、眼轴长度、屈光度、泪膜脂质层厚度(LLT)、泪膜破裂时间(BUT)、黄斑中心凹下的脉络膜厚度(SFChT)及并发症发生情况。结果治疗前后不同时间点两组患者的裸眼视力、屈光度、LLT、BUT、SFChT比较,组内不同时间点比较、时间与组间的交互效应差异均有统计学意义(均为P0.05);组内不同时间点眼轴长度比较差异有统计学意义(P0.05)。治疗后12个月观察组患者的裸眼视力、LLT降低程度、SFChT增厚程度均大于对照组(均为P0.05)。两组患者并发症发生率比较差异均无统计学意义(均为P>0.05)。结论RLRL联合角膜塑形镜控制青少年进展性近视效果显著,提高患者裸眼视力,延缓眼轴增长以及屈光度的变化,具有良好的安全性。

关键词：角膜塑形镜低能量红光照射进展性近视青少年近视防控

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Site dependence of far-source ground motions during the Wenchuan earthquake

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Earthquake Science 2009年第5期22卷 531-537页

作者： Longjun Xu Haiying Yu Wenhai Cao lili xie Research Center of Civil Engineering Disasters and Prevention Harbin Institute of Technology at Weihai Weihai 264209 China Institute of Engineering Mechanics China Earthquake Administration Harbin 150080 China Earthquake Administration of Weihai City Weihai 264209 China

This paper aimed to examine the site dependence and evaluate the methods for site analysis of far-source ground motions. This was achieved through the examination of frequency content estimated by different methods based on strong ground motions recorded at twelve far-source stations in Shandong province during the Wenchuan earthquake. The stations were located in sites with soil profiles ranging from code classes Ⅰ to Ⅲ. Approaches used included the Fourier amplitude spectrum （FAS）, the earthquake response spectrum （ERS）, the spectral ratio between the horizontal and the vertical components （H/V）, the spectral ratio between the spectra at the site and at a reference site （SRRS）, and coda wave analysis （CWA）. Results showed that major periods of these ground motions obtained by FAS, ERS and H/V ratio methods were all evidently larger than site dominant periods; the periods were also different from each other and mainly reflected the frequency content of long period components. Prominent periods obtained by the SRRS approach neither illuminated the long period aspect nor efficiently determined site features of the motions. The CWA resulted in a period close to site period for stations with good quality recordings. The results obtained in this study will be useful for the evaluation of far-source effect in constructing seismic design spectra and in selecting methods for ground motion site analysis.

关键词： Wenchuan earthquake far-source long period ground motion predominant period source effect site condition

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急性心肌梗死病人就医延迟影响因素研究进展

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护理研究 2024年第14期38卷 2538-2543页

作者：于浪琴郭婷熊楚妍彭莹程婷张娜谢丽丽涂惠南昌大学江西医学院第二附属医院江西330006 南昌大学江西医学院护理学院

对急性心肌梗死病人就医延迟现状、影响因素进行综述,旨在为临床医护人员构建就医延迟干预方案提供参考。

关键词：急性心肌梗死就医延迟预后影响因素护理综述

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Indium-organic framework CPP-3(In)derived Ag/In_(2)O_(3) porous hexagonal tubes for H_(2)S detection at low temperature

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Chinese Chemical Letters 2022年第1期33卷 551-556页

作者： Sihan Li lili xie Guifang Luo Yutong Han Ming Zhou Rawat Jaisutti Zhigang Zhu School of Medical Instrument and Food Engineering University of Shanghai for Science and TechnologyShanghai 200093China Shanghai Normal University Tianhua College Shanghai 201815China School of Environmental and Materials Engineering College of EngineeringShanghai Polytechnic UniversityShanghai 201209China Department of Physics Faculty of Science and TechnologyThammasat UniversityPathumthani 12120Thailand Thammasat Research Unit in Innovative Sensor and Nanoelectronic Devices Thammasat UniversityPathumthani 12120Thailand

There is a great demand for high-performance hydrogen sulfide(H_(2)S)sensors with low operating ***/In_(2)O_(3)hexagonal tubes with different proportions were prepared by the calcination of Ag+-impregnated indium-organic frameworks(CPP-3(In)),and the developed sensors exhibit enhanced gas-sensing performance toward H_(2)*** sensing measurements indicate that the response of Ag/In_(2)O_(3)(2.5 wt%)sensor to 5 ppm H_(2)S has the highest response(119),operated at 70℃.The Ag/In_(2)O_(3)(2.5 wt%)based sensor exhibits short response time(20 s),low detection limit(300 ppb),and good selectivity toward H_(2)S gas,which imply that the CPP-3(In)-derived Ag/In_(2)O_(3)hexagonal tube is a promising candidate to be constructed a low power-consumption H_(2)S sensor.

关键词： Ag/In_(2)O_(3) Indium-organic framework(CPP-3(In)) H_(2)S Gas sensor Low power consumption

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