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Modelling long-term deformation of granular soils incorporating the concept of fractional calculus 被引量:5
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作者 Yifei Sun Yang Xiao +1 位作者 Changjie Zheng Khairul Fikry Hanif 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2016年第1期112-124,共13页
Many constitutive models exist to characterise the cyclic behaviour of granular soils but can only simulate deformations for very limited cycles. Fractional derivatives have been regarded as one potential instrument f... Many constitutive models exist to characterise the cyclic behaviour of granular soils but can only simulate deformations for very limited cycles. Fractional derivatives have been regarded as one potential instrument for modelling memory-dependent phenomena. In this paper, the physical connection between the fractional derivative order and the fractal dimension of granular soils is investigated in detail. Then a modified elasto-plastic constitutive model is proposed for evaluating the long-term deformation of granular soils under cyclic loading by incorporating the concept of fac- tional calculus. To describe the flow direction of granular soils under cyclic loading, a cyclic flow potential consider- ing particle breakage is used. Test results of several types of granular soils are used to validate the model performance. 展开更多
关键词 Constitutive model Fractional order Fractional calculus long-term deformation
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Investigation on long-term progressive deformation of engineering slope based on comprehensive monitoring 被引量:2
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作者 ZHANG Shi-shu GUO Song-feng +9 位作者 QI Sheng-wen TANG Feng-jiao HU Jin-shan ZHAO Xiao-ping RAN Cong-yan WANG Xin ZOU Yu HUANG Xiao-lin ZHENG Bo-wen LIANG Ning 《Journal of Mountain Science》 SCIE CSCD 2022年第6期1576-1587,共12页
A landslide always results from a progressive process of slope deformation. In recent years, an increasing number of slope instabilities have occurred with regard to human engineering activities such as hydropower or ... A landslide always results from a progressive process of slope deformation. In recent years, an increasing number of slope instabilities have occurred with regard to human engineering activities such as hydropower or traffic construction in mountainous area, which cause even greater casualties and economic loss compared with the natural hazards. The development of such earth surface process may hold long period with mechanisms still not fully understood. Using monitoring technology is an effective and intuitive approach to assist analyzing the slope deformation process and their driving factors. This study presents an engineering slope excavated during the construction of Changheba Hydropower Station, which is located in the upper reaches of Dadu River, Sichuan Province, southwest China. The engineering slope experienced and featured a five-year continuous deformation which caused continuous high risks to the engineering activities. We conducted in-depth analysis for such a long-term deformation process based on ground and subsurface monitoring data, collected successive data with a series of monitoring equipment such as automated total station, borehole inclinometers and other auxiliary apparatus, and identified the deformation process based on the comprehensive analysis of monitoring data as well as field investigation. After analyzing the effects of engineering activities and natural factors on the continuous deformation, we found that the overburden strata provided deformable mass while the excavation-produced steep terrain initiated the slope deformation in limit equilibrium state over a long period of time;afterwards, the intense rainwater accelerated slope deformation in the rainy season. 展开更多
关键词 Engineering slope Mountainous area long-term deformation LANDSLIDES MONITORING STABILITY
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Short-Term and Long-Term Outcomes among COVID-19 Survivors: A Multi-Center Prospective Observational Study
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作者 Mohsin Ahmed Abdul Wadud Chowdhury +13 位作者 Md. Arifur Rahman A. K. M. Monwarul Islam Matiur Rahman Helal Uddin Ahmed Md. Shariful Islam Nahid Hasan Salahuddin Anis Shiblee Md. Habibur Rahman Mostafa Kamal Md. Nur-A-Alam Khan Aminul Islam Syed Tariq Reza A. K. M. Nasir Uddin Murtaza Khair 《International Journal of Clinical Medicine》 CAS 2024年第11期486-501,共16页
Background: Since the outbreak of the COVID-19 pandemic caused massive case fatalities across the world, people have been left with significant physical and mental disabilities, which has had an adverse impact on thei... Background: Since the outbreak of the COVID-19 pandemic caused massive case fatalities across the world, people have been left with significant physical and mental disabilities, which has had an adverse impact on their quality of life. The objective of this study is to measure the short-term and long-term outcomes among COVID-19 survivors. Methods: This is a six-month-long multicentre prospective observational study, carried out in four specialized hospitals in the capital city Dhaka, where six hundred participants were enrolled by non-probability convenience sampling. Data were collected through three structured interviews, and follow-ups were done during discharge, at 1st month, and 6th month. An analytical study was done on demographic variables, socio-economic conditions, physical findings and outcomes. Data were analysed using Statistical Package for Social Sciences (SPSS). Results: A total of 600 participants were enrolled. The mean age was 49.83. Many participants belong to the age range of 31 to 40 years. More than two-thirds (72.7%) of participants were male, whereas 27.30% were female. Most patients admitted had mild and moderate COVID-19 symptoms (40% and 58%, respectively). Among short-term COVID complications, it was found that 43.3% of the participants complained of fatigue, 32.6% of depression, 24.7% of sleep disturbance, 19% of anxiety and, 5% memory loss. In long-term COVID complications the number reduced significantly: 5% of the participants complained of fatigue, 10% of depression, 2.7% of sleep disturbance, 7.3% of anxiety and, 2.7% memory loss. The severity of lung parenchymal disease also reduced in long term COVID symptoms. The study found a statistically significant relationship between age groups and CT severity index (χ2 = 9.458, p = 0.032). Most patients (29.2%) in the under-30 age group had a CT Severity Index score of 2 & 3 (29.2%). The important CT Severity Index scores for individuals aged 30 to 60 years were 3 and 4, accounting for 37.7% and 33.3%, respectively. In the over-60 age group, 40.8% of patients showed a CT Severity Index score of 4, showing a range of 51% - 75%. Conclusion: This study found that fatigue, depression, and sleep disturbances are prevalent among COVID-19 survivors;however, these symptoms generally reduce over time. Lung problems improved;however, some patients suffered from persistent effects. Older patients, especially those with pre-existing conditions, suffer from more severe outcomes. These findings underscore the need for ongoing care for COVID-19 survivors. 展开更多
关键词 COVID-19 Survivors short-term and long-term Outcomes Lung Complications COVID-19 Outcomes long-term Complications
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Novel experimental techniques to assess the time-dependent deformations of geosynthetics under soil confinement 被引量:1
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作者 Carina Maia Lins Costa Jorge Gabriel Zornberg 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2021年第2期410-419,共10页
A new experimental approach to assess the impact of soil confinement on the long-term behavior of geosynthetics is presented in this paper.The experimental technique described herein includes a novel laboratory appara... A new experimental approach to assess the impact of soil confinement on the long-term behavior of geosynthetics is presented in this paper.The experimental technique described herein includes a novel laboratory apparatus and the use of different types of tests that allow generation of experimental data suitable for evaluation of the time-dependent behavior of geosynthetics under soil confinement.The soil-geosynthetic interaction equipment involves a rigid box capable of accommodating a cubic soil mass under plane strain conditions.A geosynthetic specimen placed horizontally at the mid-height of the soil mass is subjected to sustained vertical pressures that,in turn,induce reinforcement axial loads applied from the soil to the geosynthetic.Unlike previously reported studies on geosynthetic behavior under soil confinement,the equipment was found to be particularly versatile.With minor setup modifications,not only interaction tests but also in-isolation geosynthetic stress relaxation tests and soil-only tests under a constant strain rate can be conducted using the same device.Also,the time histories of the reinforcement loads and corresponding strains are generated throughout the test.Results from typical tests conducted using sand and a polypropylene woven geotextile are presented to illustrate the proposed experimental approach.The testing procedure was found to provide adequate measurements during tests,including good repeatability of test results.The soilegeosynthetic interaction tests were found to lead to increasing geotextile strains with time and decreasing reinforcement tension with time.The test results highlighted the importance of measuring not only the time history of displacements but also that of reinforcement loads during testing.The approach of using different types of tests to analyze the soilegeosynthetic interaction behavior is an innovation that provides relevant insight into the impact of soil confinement on the time-dependent deformations of geosynthetics. 展开更多
关键词 GEOSYNTHETICS GEOTEXTILE CREEP Stress relaxation Reinforced soil long-term deformation
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Three-dimensional consolidation deformation analysis of porous layered soft soils considering asymmetric effects 被引量:1
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作者 张治国 黄茂松 王卫东 《Journal of Central South University》 SCIE EI CAS 2014年第9期3639-3647,共9页
Long-term settlements for underground structures, such as tunnels and pipelines, are generally observed after the completion of construction in soft clay. The soil consolidation characteristic has great influences on ... Long-term settlements for underground structures, such as tunnels and pipelines, are generally observed after the completion of construction in soft clay. The soil consolidation characteristic has great influences on the long-term deformation for underground structures. A three-dimensional consolidation analysis method under the asymmetric loads is developed for porous layered soil based on Biot's classical theory. Time-displacement effects can be fully considered in this work and the analytical solutions are obtained by the state space approach in the Cartesian coordinate. The Laplace and double Fourier integral transform are applied to the state variables in order to reduce the partial differential equations into algebraic differential equations and easily obtain the state space solution. Starting from the governing equations of saturated porous soil, the basic relationship of state space variables is established between the ground surface and the arbitrary depth in the integral transform domain. Based on the continuity conditions and boundary conditions of the multi-layered pore soil model, the multi-layered pore half-space solutions are obtained by means of the transfer matrix method and the inverse integral transforms. The accuracy of proposed method is demonstrated with existing classical solutions. The results indicate that the porous homogenous soils as well as the porous non-homogenous layered soils can be considered in this proposed method. When the consolidation time factor is 0.01, the value of immediate consolidation settlement coefficient calculated by the weighted homogenous solution is 27.4% bigger than the one calculated by the non-homogeneity solution. When the consolidation time factor is 0.05, the value of excess pore water pressure for the weighted homogenous solution is 27.2% bigger than the one for the non-homogeneity solution. It is shown that the material non-homogeneity has a great influence on the long-term settlements and the dissipation process of excess pore water pressure. 展开更多
关键词 three-dimensional consolidation deformation porous layered soils asymmetric loads long-term deformation prediction transfer matrix method
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GPS monitoring and analysis of ground movement and deformation induced by transition from open-pit to underground mining 被引量:3
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作者 Fengshan Ma Haijun Zhao +4 位作者 Yamin Zhang Jie Guo Aihua Wei Zhiquan Wu Yonglong Zhang 《Journal of Rock Mechanics and Geotechnical Engineering》 2012年第1期82-87,共6页
To trace the potential hazards of open-pit slope in Longshou mine,global positioning system(GPS) is applied to monitoring ground movement and deformation induced by transition from open-pit to underground mining.Thr... To trace the potential hazards of open-pit slope in Longshou mine,global positioning system(GPS) is applied to monitoring ground movement and deformation induced by transition from open-pit to underground mining.Through long-term monitoring from 2003 to 2008,huge amounts of data were acquired.Monitoring results show that large-scale ground movement and deformation have occurred in mining area,and the movement area is ellipse-shaped.The displacement boundary of settlement trough is 2.0 km long along the exploratory line,and 1.5 km long along the strike of ore body.GPS monitoring results basically agree with the practical deformation state of open-pit slope.It is indicated that the long-term GPS monitoring is an effective way to understand the mechanism of ground movement and deformation in mine area. 更多 展开更多
关键词 open-pit ground movement long-term GPS monitoring deformation analysis
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Statistical Transformation Indicators of Short-Term to Long-Term Using Flood Regional Coefficients (Case Study: East Azarbaijan Province, Iran)
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作者 Iraj Ebn Abbas Maaroof Siosemarde 《Open Journal of Ecology》 2017年第1期34-40,共7页
Changing contexts in a long-term and short-term perspective should be managed within an integrated risk management framework that accounts for both temporary management strategies and permanent preventive measures to ... Changing contexts in a long-term and short-term perspective should be managed within an integrated risk management framework that accounts for both temporary management strategies and permanent preventive measures to reduce the impact of natural hazard processes. In this study, statistical transformation indicators of short-term (20 year) to long-term (30 year) used flood regional coefficients. After the tests of data validation and the reconstruction of missing and outlier data, the data of 18 hydrometric stations were completed for 30 years (1985 to 2014). In the next phase, the return period values were prepared for 20-year and 30-year statistical periods (1985 to 2004 and 1985 to 2014) using the HYFA software. Thus the 20-year to 30-year ratio for various return period discharges obtained and these dimensionless values were plotted for the return periods of 2, 5, 10, 20, 50 and 100 years, also fitted the logarithmic trend line and the values of coefficients of the relationship were obtained. The statistics including average, standard deviation, coefficient of variation (CV), skewness coefficient (CS) and Kurtosis coefficient (CK) were calculated for 20-year data period for each station and we identified the statistics as independent parameters and the coefficients of A and B as dependent parameter, thus analyzed using linear multivariate regression, and regional factors were obtained. In the hydrometric station with 17-027 code, the discharge using the regional factors was calculated and compared with the discharge values of 30 years data. The results showed that there is little difference between the observed and estimated values from regional factors thus this method can be used in projects that require at least 30 years of data. 展开更多
关键词 Factor Analysis FLOOD long-term short-term REGIONAL Factors
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Short-term and long-term risk factors in gastric cance
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《World Journal of Gastroenterology》 SCIE CAS 2015年第21期6434-6443,共10页
While in chronic diseases, such as diabetes, mortalityrates slowly increases with age, in oncological seriesmortality usually changes dramatically during thefollow-up, often in an unpredictable pattern. Forinstance, i... While in chronic diseases, such as diabetes, mortalityrates slowly increases with age, in oncological seriesmortality usually changes dramatically during thefollow-up, often in an unpredictable pattern. Forinstance, in gastric cancer mortality peaks in thefirst two years of follow-up and declines thereafter.Also several risk factors, such as TNM stage, largelyaffect mortality in the first years after surgery, whileafterward their effect tends to fade. Temporal trendsin mortality were compared between a gastric cancerseries and a cohort of type 2 diabetic patients. Forthis purpose, 937 patients, undergoing curativegastrectomy with D1/D2/D3 lymphadenectomy forgastric cancer in three GIRCG (Gruppo Italiano RicercaCancro Gastrico = Italian Research Group for GastricCancer) centers, were compared with 7148 type 2diabetic patients from the Verona Diabetes Study. Inthe early/advanced gastric cancer series, mortality fromrecurrence peaked to 200 deaths per 1000 personyears1 year after gastrectomy and then declined,becoming lower than 40 deaths per 1000 person-yearsafter 5 years and lower than 20 deaths after 8 years.Mortality peak occurred earlier in more advanced Tand N tiers. At variance, in the Verona diabetic cohort overall mortality slowly increased during a 10-yearfollow-up, with ageing of the type 2 diabetic patients.Seasonal oscillations were also recorded, mortalitybeing higher during winter than during summer. Alsothe most important prognostic factors presented adifferent temporal pattern in the two diseases: whilethe prognostic significance of T and N stage markedlydecrease over time, differences in survival amongpatients treated with diet, oral hypoglycemic drugsor insulin were consistent throughout the follow-up.Time variations in prognostic significance of main riskfactors, their impact on survival analysis and possiblesolutions were evaluated in another GIRCG series of568 patients with advanced gastric cancer, undergoingcurative gastrectomy with D2/D3 lymphadenectomy.Survival curves in the two different histotypes (intestinaland mixed/diffuse) were superimposed in the first threeyears of follow-up and diverged thereafter. Likewise,survival curves as a function of site (fundus vs body/antrum) started to diverge after the first year. On thecontrary, survival curves differed among age classesfrom the very beginning, due to different post-operativemortality, which increased from 0.5% in patients aged65-74 years to 9.9% in patients aged 75-91 years;this discrepancy later disappeared. Accordingly, theproportional hazards assumption of the Cox modelwas violated, as regards age, site and histology. Tocope with this problem, multivariable survival analysiswas performed by separately considering either thefirst two years of follow-up or subsequent years.Histology and site were significant predictors only aftertwo years, while T and N, although significant bothin the short-term and in the long-term, became lessimportant in the second part of follow-up. Increasingage was associated with higher mortality in the firsttwo years, but not thereafter. Splitting survival timewhen performing survival analysis allows to distinguishbetween short-term and long-term risk factors.Alternative statistical solutions could be to excludepost-operative mortality, to introduce in the modeltime-dependent covariates or to stratify on variablesviolating proportionality assumption. 展开更多
关键词 Gastric cancer Type 2 diabetes Mortality short-term RISK FACTORS long-term RISK FACTORS Survivalanalysis COX model Proportional hazards ASSUMPTION
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Short-Term and Long-Term Price Forecasting Models for the Future Exchange of Mongolian Natural Sea Buckthorn Market
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作者 Yalalt Dandar Liu Chang 《Agricultural Sciences》 2022年第3期467-490,共24页
Sea buckthorn market floated uncertainly within a narrow range. The market situation provided upward pressure on prices, and producer and consumer interest were poor, coupled with weak prices in the regional markets. ... Sea buckthorn market floated uncertainly within a narrow range. The market situation provided upward pressure on prices, and producer and consumer interest were poor, coupled with weak prices in the regional markets. The objectives of the study are: 1) to estimate the relationship between wild Sea buckthorn (SB) price and Supply, Demand, while some other factors of crude oil price and exchange rate by using simultaneous Supply-Demand and Price system equation and Vector Error Correction Method (VECM);2) to forecast the short-term and long-term SB price;3) to compare and evaluate the price forecasting models. Firstly, the data was analyzed by Ferris and Engle-Granger’s procedure;secondly, both price forecasting methodologies were tested by Pindyck-Rubinfeld and Makridakis’s procedure. The result shows that the VECM model is more efficient using yearly data;a short-term price forecast decreases, and a long-term price forecast is predicted to increase the Mongolian Sea buckthorn market. 展开更多
关键词 short-term and long-term Price Forecasting Models Simultaneous System Equation VECM Sea Buckthorn Mongolia
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Short-term warning and integrity monitoring algorithm for coal mine shaft safety 被引量:3
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作者 王坚 谭兴龙 +1 位作者 韩厚增 T.B.AFENI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第11期3666-3673,共8页
A new short-term warning and integrity monitoring algorithm was proposed for coal mine shaft safety. The Kalman filter (KF) model was used to extract real global positioning system (GPS) kinematic deformation informat... A new short-term warning and integrity monitoring algorithm was proposed for coal mine shaft safety. The Kalman filter (KF) model was used to extract real global positioning system (GPS) kinematic deformation information. The short-term warning model was built by using the two-side cumulative sum (CUSUM) test, which further improves the warning system reliability. Availability (the minimum warning deformation, MWD), false alarm rate (the average run length, ARL), missed rate (the warning delay, WD) and the relationships among them were analyzed and the method choosing warning parameters is given. A test of a deformation simulation platform shows that the warning algorithm can be effectively used for steep deformation warning. A field experiment of the Malan mine shaft in Shanxi coal area illustrates that the proposed algorithm can detect small dynamic changes and the corresponding occurring time. At given warning thresholds (MWD is 15 mm and ARL is 1000),the detected deformations of two consecutive days’ deformation sequences with the algorithm occur at the 705th epoch (705 s) and the 517th epoch (517 s), respectively. 展开更多
关键词 coal mine shaft deformation cumulative sum short-term warning Kalman filter integrity monitoring
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Rapid afterslip and short-term viscoelastic relaxation following the 2008 M_W7.9 Wenchuan earthquake 被引量:16
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作者 Zhigang Shao Rongjiang Wang +1 位作者 Yanqiang Wu Langping Zhang 《Earthquake Science》 CSCD 2011年第2期163-175,共13页
Significant postseismic deformation of the 2008 M W 7.9 Wenchuan earthquake has been observed from GPS data of the first 14 days after the earthquake. The possible mechanisms for the rapid postseismic deformation are ... Significant postseismic deformation of the 2008 M W 7.9 Wenchuan earthquake has been observed from GPS data of the first 14 days after the earthquake. The possible mechanisms for the rapid postseismic deformation are assumed to be afterslip on the earthquake rupture plane and viscoelastic relaxation of coseismiclly stress change in the lower crust or upper mantle. We firstly use the constrained least squares method to find an afterslip model which can fit the GPS data best. The afterslip model can explain near-field data very well but shows considerable discrepancies in fitting far-field data. To estimate the effect due to the viscoelastic relaxation in the lower crust, we then ignore the contribution from the afterslip and attempt to invert the viscosity structure beneath the Longmenshan fault where the Wenchuan earthquake occurred from the postseismic deformation data. For this purpose, we use a viscoelastic model with a 2D geometry based on the geological and seismological observations and the coseismic slip distribution derived from the coseismic GPS and InSAR data. By means of a grid search we find that the optimum viscosity is 9×10 18 Pa·s for the middle-lower crust in the Chengdu Basin, 4×10 17 Pa·s for the middle-lower crust in the Chuanxi Plateau and 7×10 17 Pa·s for the low velocity zone in the Chuanxi plateau. The viscoelastic model explains the postseismic deformation observed in the far-field satisfactorily, but it is considerably worse than the afterslip model in fitting the near-fault data. It suggests therefore a hybrid model including both afterslip and relaxation effects. Since the viscoelastic model produces mainly the far-field surface deformation and has fewer degree of freedoms (three viscosity parameters) than the afterslip model with a huge number of source parameters, we fix the viscositiy structure as obtained before but redetermine the afterslip distribution using the residual data from the viscoelastic modeling. The redetermined afterslip distribution becomes physically more reasonable; it is more localized and exhibits a pattern spatially complementary with the coseismic rupture distribution. We conclude that the aseismic fault slip is responsible for the near-fault postseismic deformation, whereas the viscoelastic stress relaxation might be the major cause for the far-field postseismic deformation. 展开更多
关键词 Wenchuan earthquake short-term postseismic deformation aseismic slip viscoelastic relaxation
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Long-term stability analysis of large-scale underground plant of Xiangjiaba hydro-power station 被引量:3
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作者 徐卫亚 聂卫平 +3 位作者 周先齐 石崇 王伟 冯树荣 《Journal of Central South University》 SCIE EI CAS 2011年第2期511-520,共10页
Numerical analysis of the optimal supporting time and long-term stability index of the surrounding rocks in the underground plant of Xiangjiaba hydro-power station was carried out based on the rheological theory. Firs... Numerical analysis of the optimal supporting time and long-term stability index of the surrounding rocks in the underground plant of Xiangjiaba hydro-power station was carried out based on the rheological theory. Firstly,the mechanical parameters of each rock group were identified from the experimental data; secondly,the rheological calculation and analysis for the cavern in stepped excavation without supporting were made; finally,the optimal time for supporting at the characteristic point in a typical section was obtained while the creep rate and displacement after each excavation step has satisfied the criterion of the optimal supporting time. Excavation was repeated when the optimal time for supporting was identified,and the long-term stability creep time and the maximum creep deformation of the characteristic point were determined in accordance with the criterion of long-term stability index. It is shown that the optimal supporting time of the characteristic point in the underground plant of Xiangjiaba hydro-power station is 5-8 d,the long-term stability time of the typical section is 126 d,and the corresponding largest creep deformation is 24.30 mm. While the cavern is supported,the cavern deformation is significantly reduced and the stress states of the surrounding rock masses are remarkably improved. 展开更多
关键词 large-scale underground plant rheological mechanics optimal supporting time maximum creep deformation long-termstability long-term strength
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The Study of Medium- and Short-term Prediction for Artux Earthquake (M_S=6.9) and Usunan Earthquake (M_S=5.8) 被引量:1
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作者 Jiang Zaisen, Zhao Zhencai, Wang Haitao, Wang Jiying, and Wang ShuangxuThe Second Crustal Deformation Monitoring Center, SSB, Xi’an 710054, China Seismological Bureau of Xinjiang Uygur Autonomous Region, Urumqi 830011, China 《Earthquake Research in China》 1998年第4期86-91,共6页
In this paper, the process of medium- and short-term prediction (submitted in special cards) of the Artux earthquake (MS=6.9) and the Usurian earthquake (MS=5.8) in Xinjiang area, is introduced. The imminent seismic r... In this paper, the process of medium- and short-term prediction (submitted in special cards) of the Artux earthquake (MS=6.9) and the Usurian earthquake (MS=5.8) in Xinjiang area, is introduced. The imminent seismic risk regions are judged based on long- and medium-term seismic risk regions and annual seismic risk regions determined by national seismologic analysis, combined with large seismic situation analysis. We trace and analyze the seismic situation in large areas, and judge principal risk regions or belts of seismic activity in a year, by integrating the large area’s seismicity with geodetic deformation evolutional characteristics. As much as possible using information, we study synthetically observational information for long-medium- and short-term (time domain) and large-medium -small dimensions (space domain), and approach the forecast region of forthcoming earthquakes from the large to small magnitude. A better effect has been obtained. Some questions about earthquake prediction are discussed. 展开更多
关键词 MEDIUM and short-term EARTHQUAKE prediction Large seismic SITUATION GEODETIC deformation Synthetic analysis.
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Trends of Inequalities in the Use of Long-Term Reversible Contraceptives in Burkina Faso between 2010 and 2015
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作者 Lonkila Moussa Zan Georges Guiella Adama Tiendrébéogo 《Health》 2023年第7期796-809,共14页
Background: Efforts have been made in Burkina Faso, a French-speaking country, since 2010 to improve healthcare access and provide affordable contraceptive methods to women. With the increasing prevalence of modern co... Background: Efforts have been made in Burkina Faso, a French-speaking country, since 2010 to improve healthcare access and provide affordable contraceptive methods to women. With the increasing prevalence of modern contraceptives in Burkina Faso, it is important to examine the socio-demographic factors that contribute to this new pattern of contraceptive use. This study aims to analyze the changes in socio-demographic factors associated with long-term contraceptive use and provide scientific evidence to guide policy development and action planning in family planning. Data and Methods: We utilized data from the 2010 Demographic and Health Survey, which included 17,087 women aged 15 - 49 years, and the 2015 Demographic and Health Module, which included 11,504 women in the same age group. For the analysis of contraceptive use, we focused on women who were in need of contraception (either met or unmet), of reproductive age, non-pregnant, and either married or sexually active but not married. We included users of modern reversible methods and excluded non-users, as well as users of traditional or permanent methods. Results: Our findings revealed a high prevalence of long-term contraceptive use across all categories;however, certain challenges were identified, such as lower levels of information about contraceptive methods among users and the persistence of inequalities. Family planning discussions and partner approval did not influence long-term contraceptive choice. Additionally, some providers selectively offered specific methods based on women’s life course characteristics, such as parity and marital status, despite evidence suggesting that young and nulliparous women can effectively use long-term methods. Conclusion: Given the high effectiveness of long-term contraceptive methods, it is crucial to address barriers that hinder their utilization among young and nulliparous women, as well as those who desire to delay pregnancy. Efforts should focus on improving knowledge and dispelling misconceptions surrounding long-term methods. Providers play a pivotal role in this process by adopting counseling strategies that enhance users’ understanding and facilitate informed decision-making regarding contraceptive options. 展开更多
关键词 long-term short-term Contraceptive Method Method Information COUNSELLING Burkina Faso
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Comparison of short- with long-term regeneration results after digital nerve reconstruction with musclein-vein conduits
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作者 Jennifer Lynn Schiefer Lukas Schulz +3 位作者 Rebekka Rath Stéphane Stahl Hans-Eberhard Schaller Theodora Manoli 《Neural Regeneration Research》 SCIE CAS CSCD 2015年第10期1674-1677,共4页
Muscle-in-vein conduits are used alternatively to nerve grafts for bridging nerve defects. The purpose of this study was to examine short- and long-term regeneration results after digital nerve reconstruction with mus... Muscle-in-vein conduits are used alternatively to nerve grafts for bridging nerve defects. The purpose of this study was to examine short- and long-term regeneration results after digital nerve reconstruction with muscle-in-vein conduits. Static and moving two-point discriminations and Semmes-Weinstein Monofilaments were used to evaluate sensory recovery 6–12 months and 14–35 months after repair of digital nerves with muscle-in-vein in 7 cases. Both follow-ups were performed after clinical signs of progressing regeneration disappeared. In 4 of 7 cases, a further recovery of both two-point discriminations and in another case of only the static two-point discrimination of 1–3 mm could be found between the short-term and long-term follow-up examination. Moreover, a late recovery of both two-point discriminations was demonstrated in another case. Four of 7 cases showed a sensory improvement by one Semmes-Weinstein Monofilaments. This pilot study suggests that sensory recovery still takes place even when clinical signs of progressing regeneration disappear. 展开更多
关键词 peripheral nerve regeneration muscle-in-vein conduits digital nerves sensory recovery Semmes-Weinstein two-point discrimination outcome short-term long-term
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Video caching and scheduling with edge cooperation
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作者 Zhidu Li Fuxiang Li +2 位作者 Tong Tang Hong Zhang Jin Yang 《Digital Communications and Networks》 SCIE CSCD 2024年第2期450-460,共11页
In this paper,we explore a distributed collaborative caching and computing model to support the distribution of adaptive bit rate video streaming.The aim is to reduce the average initial buffer delay and improve the q... In this paper,we explore a distributed collaborative caching and computing model to support the distribution of adaptive bit rate video streaming.The aim is to reduce the average initial buffer delay and improve the quality of user experience.Considering the difference between global and local video popularities and the time-varying characteristics of video popularity,a two-stage caching scheme is proposed to push popular videos closer to users and minimize the average initial buffer delay.Based on both long-term content popularity and short-term content popularity,the proposed caching solution is decouple into the proactive cache stage and the cache update stage.In the proactive cache stage,we develop a proactive cache placement algorithm that can be executed in an off-peak period.In the cache update stage,we propose a reactive cache update algorithm to update the existing cache policy to minimize the buffer delay.Simulation results verify that the proposed caching algorithms can reduce the initial buffer delay efficiently. 展开更多
关键词 Video service Distributed and collaborative caching long-term popularity short-term popularity
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Radical resection of pancreatic cancer 被引量:4
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作者 Alexander Koliopanos C Avgerinos +2 位作者 Athanasios Farfaras C Manes Christos Dervenis 《Hepatobiliary & Pancreatic Diseases International》 SCIE CAS 2008年第1期11-18,共8页
BACKGROUND: Pancreatic adenocarcinoma (PCa) is a disease with dismal prognosis, and the only possibility of cure, albeit small, is based on the combination of complete resection with negative histopathological margins... BACKGROUND: Pancreatic adenocarcinoma (PCa) is a disease with dismal prognosis, and the only possibility of cure, albeit small, is based on the combination of complete resection with negative histopathological margins (R0 resection) with adjuvant treatment. Therefore, a lot of effort has been made during the last decade to assess the role of extensive surgery in both local recurrence and survival of patients with PCa. DATA SOURCES: Medline search and manual cross- referencing were utilized to identify published evidence- based data for PCa surgery between 1973 and 2006, with emphasis to feasibility, efficacy, long-term survival, disease free survival, recurrence rates, pain relief and quality of life. RESULTS: Extended surgery is safe and feasible in high volume surgical centers with comparable short-term results. Organ preserving surgery is a main goal because of quality of life reasons and is performed whenever possible from the tumor extent. Concerning long-term survival major vein resection does not adversely affect outcome. To date, there are no changes in long-term survival attributed to the extended lymph node dissection. However, there is a benefit in locoregional control with fewer local recurrences and extended lymphadenectomy allows better staging for the disease. CONCLUSIONS: Extended PCa surgery is safe and feasible despite the inconclusive results in patient’s survival benefit. In the future, appropriately powered randomized trials of standard vs. extended resections may show improved outcomes for PCa patients. 展开更多
关键词 pancreatic adenocarcinoma extended lymphadenectomy vascular resection survival benefit short-term outcome long-term outcome MORBIDITY MORTALITY
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Discussion on the parameters of design waves 被引量:3
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作者 王言英 《Journal of Marine Science and Application》 2008年第3期162-167,共6页
In order to respond the discredit on the design wave standard and to recommend new consideration on design wave parameters, based on the long-term distribution of statistic characteristics of waves and the short-term ... In order to respond the discredit on the design wave standard and to recommend new consideration on design wave parameters, based on the long-term distribution of statistic characteristics of waves and the short-term probability properties of sea state defined by giving the return period, the calculation of the return period, the height, the period, and the oceanic wave parameters of the design wave and the forecasting methods are discussed in this paper. To provide references for the operation reliability of floating structures in the extreme sea state, the method of determining the design wave parameters is resurveyed. A proposal is recommended that the design wave, which can be either significant wave with 500-year of the return period, or the maximum wave with 1/N of exceeding probability, 100-year of the return period, can be applied in the engineering design practice. 展开更多
关键词 ocean waves short-term distribution long-term distribution design waves
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The detrimental effects of lipopolysaccharideinduced neuroinflammation on adult hippocampal neurogenesis depend on the duration of the pro-inflammatory response 被引量:3
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作者 Martha Pérez-Domínguez Evangelina ávila-Mu?oz +1 位作者 Eduardo Domínguez-Rivas Angélica Zepeda 《Neural Regeneration Research》 SCIE CAS CSCD 2019年第5期817-825,共9页
Adult hippocampal neurogenesis is a finely tuned process regulated by extrinsic factors. Neuroinflammation is a hallmark of several pathological conditions underlying dysregulation of neurogenesis. In animal models, l... Adult hippocampal neurogenesis is a finely tuned process regulated by extrinsic factors. Neuroinflammation is a hallmark of several pathological conditions underlying dysregulation of neurogenesis. In animal models, lipopolysaccharide(LPS)-induced neuroinflammation leads to a neurogenic decrease mainly associated to the early inflammatory response. However, it is not well understood how the neuroinflammatory response progresses over time and if neurogenesis continues to be diminished during the late neuroinflammatory response. Moreover, it is unknown if repeated intermittent administration of LPS along time induces a greater reduction in neurogenesis. We administered one single intraperitoneal injection of LPS or saline or four repeated injections(one per week) of LPS or saline to young-adult mice. A cohort of new cells was labeled with three 5-bromo-2-deoxyuridine injections(one per day) 4 days after the last LPS injection. We evaluated systemic and neuroinflammation-associated parameters and compared the effects of the late neuroinflammatory response on neurogenesis induced by each protocol. Our results show that 1) a single LPS injection leads to a late pro-inflammatory response characterized by microglial activation, moderate astrocytic reaction and increased interleukin-6 levels. This response correlates in time with decreased neurogenesis and 2) a repeated intermittent injection of LPS does not elicit a late pro-inflammatory response although activated microglia persists. The latter profile is not accompanied by a continued longterm hippocampal neurogenic decrease. Hereby, we provide evidence that the neuroinflammatory response is a dynamic process that progresses in a milieu-dependent manner and does not necessarily lead to a neurogenic decrease, highlighting the complex interaction between the immune system and neurogenesis. 展开更多
关键词 DENTATE GYRUS subgranular zone inflammation microglia ASTROCYTES IL-6 cytokines cell proliferation neural PROGENITOR cells IMMATURE neurons long-term short-term adult hippocampal NEUROGENESIS
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Voltage-dependent plasticity and image Boolean operations realized in a WOx-based memristive synapse 被引量:1
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作者 Jiajuan Shi Ya Lin +4 位作者 Tao Zeng Zhongqiang Wang Xiaoning Zhao Haiyang Xu Yichun Liu 《Journal of Semiconductors》 EI CAS CSCD 2021年第1期128-133,共6页
The development of electronic devices that possess the functionality of biological synapses is a crucial step towards neuromorphic computing.In this work,we present a WOx-based memristive device that can emulate volta... The development of electronic devices that possess the functionality of biological synapses is a crucial step towards neuromorphic computing.In this work,we present a WOx-based memristive device that can emulate voltage-dependent synaptic plasticity.By adjusting the amplitude of the applied voltage,we were able to reproduce short-term plasticity(STP)and the transition from STP to long-term potentiation.The stimulation with high intensity induced long-term enhancement of conductance without any decay process,thus representing a permanent memory behavior.Moreover,the image Boolean operations(including intersection,subtraction,and union)were also demonstrated in the memristive synapse array based on the above voltage-dependent plasticity.The experimental achievements of this study provide a new insight into the successful mimicry of essential characteristics of synaptic behaviors. 展开更多
关键词 MEMRISTOR artificial synapse short-term plasticity long-term potentiation image Boolean operations
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