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An equivalent-boundary method for the shell analysis of buried pipelines under fault movement

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Acta Seismologica Sinica(English Edition) 2004年第Z1期17卷 150-156页

作者： LIU Ai-wen(刘爱文) HU Yu-xian(胡聿贤) ZHAO Feng-xin(赵凤新) LI Xiao-jun(李小军) Takada Shiro(高田至郎) ZHAO Lei(赵雷) Institute of Geophysics China Earthquake Administration Beijing 100081 China Institute of Geophysics China Earthquake Administration Beijing 100081 China Institute of Geophysics China Earthquake Administration Beijing 100081 China Institute of Geophysics China Earthquake Administration Beijing 100081 China Kobe University Kobe 6570013 Japan Institute of Geophysics China Earthquake Administration Beijing 100081 China

A new shell finite element method (FEM) model with an equivalent boundary is presented for estimating the re- sponse of a buried pipeline under large fault movement. The length of affected pipeline under fault movement is usually too long for a shell-mode calculation because of the limitation of memory and time of computers. In this study, only the pipeline segment near fault is modeled with plastic shell elements to study the local buckling and the large section deformation in pipe. The material property of pipe segment far away from the fault is considered as elastic, and nonlinear spring elements at equivalent boundaries are obtained and applied to two ends of shell model. Compared with the fixed-boundary shell model, the shell model with an equivalent boundary proposed by the study can remarkably reduce the needed memory and calculating time.

关键词： buried pipeline fault movement shell analysis equivalent boundary

The value of community science data to analyze long-term avian trends in understudied regions:The state of birds in Türkiye

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Avian Research 2023年第4期14卷 695-705页

作者： Kyle D.Kittelberger Colby J.Tanner Nikolas D.Orton Çagan Hakkı Sekercioglu School of Biological Sciences University of Utah257 S 1400 ESalt Lake CityUT84112USA KoçUniversity Department of Molecular Biology and GeneticsIstanbulTürkiye KuzeyDoga Dernegi Istasyon MahallesiIsmail Aytemiz Caddesi36200 KarsTürkiye

Recent studies have revealed concerning declines in bird populations in Europe and other parts of the world.In understudied but biodiverse regions,especially those that are located along key migratory flyways,there is an unmet need to evaluate the status of resident and migratory birdlife for avian conservation ecology.This is especially urgent at a time when recent regional studies have highlighted the scale of the decline of the European and Palearctic avifauna.Rapidly growing community science datasets may help bridge the gaps in our understanding of long-term regional avifaunal trends.In this study,we used eBird data submitted by observers in Türkiye to undertake the first long-term assessment of the state of the country’s birds from 2001 to 2022.We evaluated population trends based on presence-absence data of species to determine if any birds have significantly increased or decreased in the country so far this century.We provide a list of trends for 418 bird species that had large enough sample sizes of eBird observations from Türkiye,and highlight which species have significantly declined or increased.We found that 63 species have significantly declined in detection while 120 have significantly increased during the study period.Our findings provide a baseline for the future monitoring of Türkiye’s birds and help contextualize population changes of birds in Türkiye against those occurring at the continental(Palearctic)scale.Additionally,we include movement classifications for all of the bird species in this study.We also provide a framework to effectively use eBird data to assess long-term avifaunal changes at the country-level in other understudied regions.Finally,we highlight ways in which eBirders in Türkiye and elsewhere can strengthen the quality and value of community ornithology data for population assessments and avian conservation ecology.

关键词： Avian ecology Bird conservation Citizen science Presence-absence Middle east movement Palearctic Threat status

THE DESTRUCTION OF ANCIENT ECOLOGICAL ENVIRONMENT AND THE movement OF CIVILIZATION CENTER IN CHINA

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Chinese Geographical Science 1992年第4期2卷 92-98页

作者：孔繁德 National Training Institute of Environmental Management Qinhuangdao 066000 PRC

China is one of the ancient civilization countries. Owing to the blind reclamation, the vegetation had been destroyed, causing soil erosion and desertification, and making the civilization center move to the Changjiang (Yangtze) River valley from the Huanghe (Yellow) River. This movement began in the Qin and Han dynasties (221 B.C-220 A.D.) because at that time the large-scale reclamation was felled, the grassland was reclaimed into farmland, the vegetation was seriously destroyed in the loess and north of the Huanghe River, and the climate was getting colder; and the turn from north to south occurred in the Sui and Tang dynasties (581-907 A.D.) and completed in the Song Dynasty (960-1279 A.D.). However, at present the vegetation damage of the Changjiang River valley is very serious too and the silt carrying capacity of the Changjiang River is increasing sharply; thus the Changjiang River is in danger of becoming a second Huanghe River, so we must pay attention to the protection of ecological

关键词： blind reclamation destruction of vegetation soil erosion desertification movement of civilization center

Law governing strata and ground movement due to sub-critical extraction

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中国有色金属学会会刊：英文版 2005年第S1期15卷 58-61页

作者： DAI Hua-yang~(1,2), WANG Jin-zhuang~1, CAI Mei-feng~2, YANG Ling~3 (1. China University of Mining and Technology Beijing Campus, Beijing 100083, China 2. Beijing, University of Science and Technology Beijing 100083, China 3. Central Coal Research Institute, Tangshan Branch, Tangshan 063012, China)

The strata movement induced by sub-critical extraction is a problem not receiving due attention because of its relatively small magnitude of deformation. However, with the increase of mining depth, sub-critical extraction has become a general phenomenon. This calls for an in-depth investigation into the characteristics of ground movements observed under different extents of sub-critical extraction, so as to determine the appropriate mining technique for use. Following a discussion of the factors influencing the extent of super-critical extraction, the super-critical extraction extent evaluation criteria was presented, the characteristics and laws of the strata and ground movements caused by such an extraction condition were systematically analyzed, and the mechanism of surface subsidence induced by sub-critical extraction was revealed. The result of study may serve as a basis for the development of the strata and ground movement prediction model and the mining techniques appropriate for use at depth beneath surface structures and buildings.

关键词： sub-critical extraction strata and ground movement extent of mining evaluation criteria.

Numerical simulation of surface movement laws under different unconsolidated layers thickness

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中国有色金属学会会刊：英文版 2011年第S3期21卷 599-603页

作者： DAI Hua-yang1, LI Wen-chang2, LIU Yi-xin1,3, JIANG Yao-dong3 1. College of Geosicence and Surveying Engineering, China University of Mining and Technology, Beijing 100083, China 2. College of Resources and Safety Engineering, China University of Mining and Technology, Beijing 100083, China 3. College of Mechanics and Civil Engineering, China University of Mining and Technology, Beijing 100083, China

Based on specific geology and mining conditions of certain coal working face in China, a series of numerical models under different unconsolidated layers thickness were respectively established by employing FLAC3D. The relationship between the unconsolidated layers thickness and surface movement laws was studied. Maximum surface subsidence, Maximum horizontal displacement and surface subsidence degree were obtained. Contours of surface subsidence/horizontal displacement and curves were drawn. Some laws of surface subsidence/horizontal displacement were analyzed. The role of the unconsolidated layers in surface subsidence was revealed. It is significant to predict surface subsidence of thick unconsolidated layers for coal mine and take effective measures to control surface subsidence.

关键词： unconsolidated layers surface movement numerical simulation deep mining FLAC3D

Wearable energy harvesters generating electricity from low-frequency human limb movement

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Microsystems & Nanoengineering 2018年第1期4卷 165-177页

作者： Keli Li Qisheng He Jiachou Wang Zhiguo Zhou Xinxin Li College of Life and Environmental Sciences Shanghai Normal University200234 ShanghaiChina State Key Laboratory of Transducer Technology Shanghai Institute of Microsystem and Information TechnologyChinese Academy of Sciences200050 ShanghaiChina The University of Chinese Academy of Sciences 100049 BeijingChina

A wearable energy harvester technology is developed for generating electricity from the movement of human joints.A micro-electroplated ferromagnetic nickel cantilever is integrated with a piezoelectric element and bonded on a flexible substrate.Based on the magnetic interaction between the magnetized cantilever and a magnet on the substrate,a novel vertical-vibration frequency-up-conversion(FUC)structure is formed to generate stable amounts of electric energy per cycle from the horizontal substrate stretching/rebounding.The two ends of the flexible substrate are attached on both sides of a limb joint to transform joint rotation into substrate stretching.During limb movement,the flexible substrate is horizontally stretched and rebounded,causing the cantilever to vertically release from and return to the magnet,thereby exciting the piezoelectric cantilever into resonant generation.Since the horizontal lowfrequency limb movement is perpendicular to the vertical high-frequency resonance,the stretch has little influence on the resonance of the cantilever.Thus the generated energy is always stable within a wide frequency range of limb movements.The performance of the novel harvester is experimentally verified using a stretching/rebounding movement cycle,where the cycle corresponds to the frequency range of 0.5–5.0 Hz.Within one stretching/rebounding movement cycle,the generated electric energy is stable in the approximate range of 0.56–0.69μJ for the whole frequency range.Two flexible harvesters are worn on the human elbow and knee for a body kinetic energy harvesting test.Considerable power can always be generated under typical low-frequency limb movements,such as squatting,walking,jogging,and fast running,where the peak-to-peak generated voltages are always approximately 4.0 V.Additionally,energy harvesting under two-directional area stretching is also realized by adjusting the FUC structure layout.The flexible-substrate harvester is promising for various wearable applications.

关键词： movement stretching energy

Defining Velocity and Acceleration Ranges for Time-Motion Analysis from a 7-Sided Game in U11 Soccer Players Using Global Positioning System Devices:A Case Study

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Journal of Science in Sport and Exercise 2023年第2期5卷 167-173页

作者： Abd-Elbasset Abaïdia Grégory Dupont Georges Baquet Universitéde Lille EA 7369-URePSSS-Unitéde Recherche Pluridisciplinaires Sport SantéSociété59000 LilleFrance Research Institute for Sport and Exercise Sciences Liverpool John Moores University LiverpoolUK

The aims of this study were(1)to define speed and acceleration thresholds from youth match activity of soccer players and(2)to analyze the activity performed by young soccer players during a match using GPS devices and according to these thresholds.Ten U11 soccer players from a professional club participated in a 7-sided match being equipped with global positioning system(GPS)devices(sampling frequency 5 Hz)to measure the speed of each player.The Kernel Density Esti-mate(KDE)was used to observe the occurrences of velocities.The range of velocities was described by a distribution curve,from which the speed and acceleration thresholds for each category of movement were defined and time–motion analysis of the match was made.The model with 4 Gaussian laws was the best when using the Akaike Information Criterion(AIC).In this study,the thresholds defined for each category of movement were:standing(movement considered as a sprint for each category of movement:standing(0.3 m/s^(2)),walking(0.66 m/s^(2)),slow running(1.01 m/s^(2))or fast running(0.97 m/s^(2)).All the acceleration thresholds were significantly different from each other(Pmovement.This study has also defined sprint and acceleration thresholds for this category of age.

关键词： Football Sprint Accelerations movement Youth

movement and strain conditions of active blocks in the Chinese mainland

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Science China Earth Sciences 2003年第Z2期46卷 82-117页

作者： LI Yanxing (李延兴) YANG Guohua (杨国华) LI Zhi (李智) GUO Liangqian (郭良迁) HUANG Cheng (黄珹) ZHU Wenyao (朱文耀) FU Yang (符养) WANG Qi (王琪) JIANG Zaisen (江在森) WANG Min (王敏) First Crustal Deformation Monitoring Center China Seismological Bureau Tianjin 300180 China First Crustal Deformation Monitoring Center China Seismological Bureau Tianjin 300180 China First Crustal Deformation Monitoring Center China Seismological Bureau Tianjin 300180 China First Crustal Deformation Monitoring Center China Seismological Bureau Tianjin 300180 China Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China Institute of Seismology China Seismological Bureau Wuhan 430071 China Center for Earthquake Analysis and Prediction China Seismological Bureau Beijing 100036 China Center for Earthquake Analysis and Prediction China Seismological Bureau Beijing 100036 China

The definition of active block is given from the angles of crustal deformation and strain. The movement and strain parameters of active blocks are estimated according to the unified velocity field composed of the velocities at 1598 GPS stations obtained from GPS measurements carried out in the past years in the Chinese mainland and the surrounding areas. The movement and strain conditions of the blocks are analyzed. The active blocks in the Chinese mainland have a consistent E-trending movement component, but its N and S components are not consistent. The blocks in the western part have a consistent N-trending movement and the blocks in the eastern part have a consistent S-trending movement. In the area to the east of 90°E, that is the area from Himalayas block towards NE, the movement direction of the blocks rotates clockwisely and the movement rates of the blocks are different. Generally, the movement rate is large in the west and south and small in the east and north with a difference of 3 to 4 times between the rates in the west and east. The distributions of principal compressive strain directions of the blocks are also different. The principal strain of the blocks located to the west of 90oE is basically in the SN direction, the principal compressive strain of the blocks in the northeastern part of Qingzang plateau is roughly in the NE direction and the direction of principal compressive strain of the blocks in the southeastern part of Qingzang plateau rounds clockwisely the east end of Himalayas structure. In addition, the principal strain and shear strain rates of the blocks are also different. The Himalayas and Tianshan blocks have the largest principal compressive strain and the maximum shear strain rate. Then, Lhasa, Qiangtang, Southwest Yunnan (SW Yunnan), Qilian and Sichuan-Yunan (Chuan-Dian) blocks followed. The strain rate of the blocks in the eastern part is smaller. The estimation based on the stain condition indicates that Himalayas block is still the area with the most intensive tectonic activi

关键词： active block, movement condition, strain condition.

Dislocation movement in Nitrogen-Doped Czochralski Silicon

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Chinese Physics Letters 1996年第5期13卷 382-385页

作者： WEI Ya-dong LIANG Jun-wu Department of Physics Shanxi UniversityTaiyuan 030006 Institute of Semiconductors Chinese Academy of SciencesBeijing 100083

Dislocation movemnent in N-doped Czochralski silicon(Cz-Si)was surrveyed by four point bend method,Dislocation mnovemnent velocities in.Cz-Si doped with nitrogen,with both nitrogen and antimony,and with only antimony were investigated,The order of measured dislocation movement velocities,at 700℃≤T≤800℃ and under resolved stress σ=4.1 kg/mm^(2),was Vsp,O>V_(N,sb,O)>V_(N,O).The experiments showed that nitrogen doping could retard the movement ofdislocations.

关键词： Dislocation stress movement