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Effects of Vegetation Type on Surface Elevation Change in Liaohe River Delta Wetlands Facing Accelerated Sea Level Rise 被引量:5
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作者 WANG Guodong WANG Ming +3 位作者 JIANG Ming LYU Xianguo HE Xingyuan WU Haitao 《Chinese Geographical Science》 SCIE CSCD 2017年第5期810-817,共8页
Rising sea levels threaten the sustainability of coastal wetlands around the globe. The ability of coastal marshes to maintain their position in the intertidal zone depends on the accumulation of both organic and inor... Rising sea levels threaten the sustainability of coastal wetlands around the globe. The ability of coastal marshes to maintain their position in the intertidal zone depends on the accumulation of both organic and inorganic materials, and vegetation is important in these processes. To study the effects of vegetation type on surface elevation change, we measured surface accretion and elevation change from 2011 to 2016 using rod surface elevation table and feldspar marker horizon method (RSET-MH) in two Phragmites and two Suaeda marshes in the Liaohe River Delta. The Phragmites marshes exhibited higher rates of surface accretion and elevation change than the Suaeda marshes. The two Phragmites marsh sites had average surface elevation change rates at 8.78 mm/yr and 9.26 mm/yr and surface accretion rates at 17.56 mm/yr and 17.88 mm/yr, respectively. At the same time, the two Suaeda marsh sites had average surface elevation change rates at 5.77 mmJyr and 5.91 mm/yr and surface accretion rates at 13.42 mm/yr and 14.38 mm/yr, respectively. The elevation change rates in both the Phragmites marshes and the Suaeda marshes in the Liaohe River Delta could keep pace and even continue to gain elevation relative to averaged sea level rise in the Bohai Sea reported by the 2016 State Oceanic Administration, Peo- ple's Republic of China projection (2.4-5.5 mm/yr) in current situations. Our data suggest that vegetation is important in the accretionary processes and vegetation type could regulate the wetland surface elevation. However, the vulnerability of coastal wetlands in the Liaohe River Delta need further assessment considering the accelerated sea level rise, the high rate of subsidence, and the declining sediment delivery, especially for the Suaeda marshes. 展开更多
关键词 sea level rise wetland elevation surface accretion Phragmites marsh Suaeda marsh Liaohe River Delta
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The relation between serum phosphorus levels and long-term mortality in Chinese patients with ST-segment elevation myocardial infarction
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作者 Guo-Hua ZHU Xi-Peng SUN +5 位作者 Zhi LIU Zhen-Xing FAN Yan-Ling WANG Jing TAN Jing LI Qi HUA 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2019年第10期775-781,共7页
Background Elevated serum phosphorus levels may be associated with adverse outcomes in cardiovascular disease. This study aimed to investigate the relation between serum phosphorus levels and risk of all-cause mortali... Background Elevated serum phosphorus levels may be associated with adverse outcomes in cardiovascular disease. This study aimed to investigate the relation between serum phosphorus levels and risk of all-cause mortality in Chinese patients with ST-segment elevation myocardial infarction (STEMI) who had preserved renal function at baseline. Methods We enrolled patients with STEMI who had preserved renal function at baseline in Xuanwu Hospital from January 2011 to December 2016. Those patients were divided into four groups based on serum phosphorus levels. All-cause mortality rates were compared between groups. Mean duration of follow up was 54.6 months. We used Cox proportional-hazards models to examine the relation between serum phosphorus levels and all-cause mortality after adjustment for potential confounders. Results 1989 patients were involved and 211 patients (10.6%) died during follow-up. Based on serum phosphorus levels, patients were categorized into the following groups:< 2.50 mg/dL (n = 89), 2.51–3.50 mg/dL (n = 1066), 3.51–4.50 mg/dL (n = 672) and > 4.50 mg/dL (n = 162), respectively. The lowest mortality occurred in patients with serum phosphorus levels between 2.51–3.50 mg/dL, with a multivariable-adjusted hazard ratio of 1.19 (95% CI: 0.64–1.54), 1.37 (95% CI: 1.22–1.74), and 1.46 (95% CI: 1.35–1.83) in patients with serum phosphorus levels of < 2.50 mg/dL, 3.51–4.50 mg/dL and > 4.50 mg/dL, respectively. Conclusions Elevated serum phosphorus levels were associated with all-cause mortality in Chinese patients with STEMI who had preserved renal function at baseline. 展开更多
关键词 Mortality Serum phosphorus levelS ST-SEGMENT elevation MYOCARDIAL INFARCTION
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Web-Based Sea Level Change Simulation System Using PNG Elevation Tiles and Smart Tile Architecture
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作者 Koki Iwao Yoshiharu Nishioka Kaoru Kitao 《Journal of Geographic Information System》 2020年第4期291-301,共11页
We have developed a web-based processing system that can simulate positive and negative sea level changes globally by selecting the best Digital Elevation Model (DEM) for a target region from multiple DEMs. A PNG elev... We have developed a web-based processing system that can simulate positive and negative sea level changes globally by selecting the best Digital Elevation Model (DEM) for a target region from multiple DEMs. A PNG elevation tile format is used as the DEM format, which reduces the DEM data size. The PNG tile format implements client-based processing, and the DEM data are provided from different websites. In addition, the smart tile architecture is adopted, which enables on-demand simulation by adding a tile conversion process (<em>i.e.</em>, a DEM selection process) during image drawing by using JavaScript. To demonstrate the system, we have employed three DEMs,<em> i.e.</em>, the Geospatial Information Authority of Japan (GSI) map (~10-m resolution), the ASTER Global Digital Elevation Models (ASTER GDEM version 3) as global land area (~30-m resolution), and the General Bathymetric Chart of the Oceans as bathymetric data (~1000-m resolution). The ASTER Global Water Bodies Database is also used in the data selection process. The GSI provides their DEM in a PNG elevation tile format, and the other data are provided by the Geological Survey of Japan in PNG elevation tile format. We assume the current DEM sea level as 0 m, and the sea level can be changed to an arbitrary integer value (<span style="white-space:nowrap;">&minus;</span>10,000 to 10,000 m). Combining ASTER GDEM for land and GEBCO for sea makes it possible to target DEM of the whole earth. Moreover, it was shown that if a higher resolution DEM is available, it is possible to combine the higher resolution DEM in that area. The combining the PNG elevation tile format with the smart tile architecture demonstrates the possibilities of a client-based web processing service like that of the server-based OGC Web Processing Service. 展开更多
关键词 DEM Sea level PNG elevation Tile Smart Tile Architecture Web Processing
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Proso Millet Protein Elevates Plasma Level of High-Density Lipoprotein:A New Food Function of Proso Millet 被引量:24
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作者 N. NISHIZAWA S. SHIMANUKI +5 位作者 H. FUJIHASHI H. WATANABE Y. FUDAMOTO AND T. NAGASAWA (Department of Bioscience and Technology, Faculty of Agriculture, Iwate University Morioka, Iwate 020, Japan Research Laboratory,Nitto Best Co., Ltd, Sagae, Yamagata 991 Ka 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 1996年第2期209-212,共4页
We examined the effects of dietary proso-millet protein on plasma levels of high-density lipoprotein (HDL) cholesterol in different rats from animals reported in our previous studies. The results showed also, in this ... We examined the effects of dietary proso-millet protein on plasma levels of high-density lipoprotein (HDL) cholesterol in different rats from animals reported in our previous studies. The results showed also, in this animal, that the ingestion of the millet protein elevates plasma levels of HDL-cholesterol like our earlier works. Taking into account the anti-atherogenic function of HDL, therefore, the millet protein would be useful as a new food ingredient which has the function that regulates cholesterol metabolism 展开更多
关键词 HDL Proso Millet Protein elevates Plasma level of High-Density Lipoprotein
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Terrain Rendering LOD Algorithm Based on Improved Restrictive Quadtree Segmentation and Variation Coefficient of Elevation 被引量:2
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作者 Zhenwu Wang Xiaohua Lu 《Journal of Beijing Institute of Technology》 EI CAS 2018年第4期617-622,共6页
Aiming to deal with the difficult issues of terrain data model simplification and crack disposal,the paper proposed an improved level of detail(LOD)terrain rendering algorithm,in which a variation coefficient of eleva... Aiming to deal with the difficult issues of terrain data model simplification and crack disposal,the paper proposed an improved level of detail(LOD)terrain rendering algorithm,in which a variation coefficient of elevation is introduced to express the undulation of topography.Then the coefficient is used to construct a node evaluation function in the terrain data model simplification step.Furthermore,an edge reduction strategy is combined with the improved restrictive quadtree segmentation to handle the crack problem.The experiment results demonstrated that the proposed method can reduce the amount of rendering triangles and enhance the rendering speed on the premise of ensuring the rendering effect compared with a traditional LOD algorithm. 展开更多
关键词 terrain data model simplification crack disposal level of detail(LOD)terrain rendering algorithm variation coefficient of elevation node evaluation function restrictive quadtree segmentation
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Morphodynamic signatures derived from daily surface elevation dynamics can explain the morphodynamic development of tidal flats 被引量:1
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作者 Tim J.Grandjean Jaco C.de Smit +4 位作者 Jim van Belzen Gregory S.Fivash Jeroen van Dalen Tom Ysebaert Tjeerd J.Bouma 《Water Science and Engineering》 EI CAS CSCD 2023年第1期14-25,共12页
Understanding the sensitivity of tidal flats to environmental changes is challenging.Currently,most studies rely on process-based models to systematically explain the morphodynamic evolution of tidal flats.In this stu... Understanding the sensitivity of tidal flats to environmental changes is challenging.Currently,most studies rely on process-based models to systematically explain the morphodynamic evolution of tidal flats.In this study,we proposed an alternative empirical approach to explore tidal flat dynamics using statistical indices based on long-term time series of daily surface elevation development.Surface elevation dynamic(SED)indices focus on the magnitude and period of surface elevation changes,while morphodynamic signature(MDS)indices relate sediment dynamics to environmental drivers.The statistical analyses were applied to an intervention site in the Netherlands to determine the effect of recently constructed groynes on the tidal flat.Using these analyses,we were able to(1)detect a reduction in the daily SED and(2)determine that the changes in the daily SED were predominantly caused by the reduction in wave impact between the groynes rather than the reduction in tidal currents.Overall,the presented results showed that the combination of novel statistical indices provides new insights into the trajectories of tidal flats,ecosystem functioning,and sensitivity to physical drivers(wind and tides).Finally,we suggested how the SED and MDS indices may help to explore the future trajectories and climate resilience of intertidal habitats. 展开更多
关键词 Surface elevation dynamics Tidal flat trajectories Morphodynamic development Morphodynamic signature Bed level dynamics
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Modeling the Risks of Climate Change and Global Warming to Humans Settled in Low Elevation Coastal Zones in Louisiana, USA
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作者 Yaw A. Twumasi Edmund C. Merem +8 位作者 John B. Namwamba Tomas Ayala-Silva Ronald Okwemba Olipa S. Mwakimi Kamran Abdollahi Onyumbe E. Ben Lukongo Kellyn LaCour-Conant Joshua Tate Caroline O. Akinrinwoye 《Atmospheric and Climate Sciences》 2020年第3期298-318,共21页
This paper seeks to identify high risk areas that are prone to flooding, caused by sea level rise because of high impacts of global climate change resulting from global warming and human settlements in low-lying coast... This paper seeks to identify high risk areas that are prone to flooding, caused by sea level rise because of high impacts of global climate change resulting from global warming and human settlements in low-lying coastal elevation areas in Louisiana, and model and understand the ramifications of predicted sea-level rise. To accomplish these objectives, the study made use of accessible public datasets to assess the potential risk faced by residents of coastal lowlands of Southern Louisiana in the United States. Elevation data was obtained from the Louisiana Statewide Light Detection and Ranging (LiDAR) with resolution of 16.4 feet (5 m) distributed by Atlas. The data was downloaded from Atlas website and imported into Environmental Systems Research Institute’s (ESRI’s) ArcMap software to create a single mosaic elevation image map of the study area. After mosaicking the elevation data in ArcMap, Spatial Analyst extension software was used to classify areas with low and high elevation. Also, data was derived from United States Geological Survey (USGS) Digital Elevation Model (DEM) and absolute sea level rise data covering the period 1880 to 2015 was acquired from United States Environmental Protection Agency (EPA) website. In addition, population data from U.S. Census Bureau was obtained and coupled with elevation data for assessing the risks of the population residing in low lying areas. Models of population trend and cumulative sea level rise were developed using statistical methods and software were applied to reveal the national trends and local deviations from the trends. The trends of population changes with respect to sea level rise and time in years were modeled for the low land coastal parishes of Louisiana. The expected years for the populations in the study area to be at risk due to rising sea level were estimated by models. The geographic information systems (GIS) results indicate that areas of low elevation were mostly located along the coastal Parishes in the study area. Further results of the study revealed that, if the sea level continued to rise at the present rate, a population of approximately 1.8 million people in Louisiana’s coastal lands would be at risk of suffering from flooding associated with the sea level having risen to about 740 inches by 2040. The population in high risk flood zone was modeled by the following equation: <em>y</em> = 6.6667<em>x</em> - 12,864, with R squared equal to 0.9964. The rate of sea level rise was found to increase as years progressed. The slopes of models for data for time periods, 1880-2015 (entire data) and 1970-2015 were found to be, 4.2653 and 6.6667, respectively. The increase reflects impacts of climate change and land management on rate of sea level rise, respectively. A model for the variation of years with respect to cumulative sea level was developed for use in predicting the year when the cumulative sea level would equal the elevation above sea level of study area parishes. The model is given by the following equation: <em>y</em> = 0.1219<em>x</em> + 1944.1 with R square equal to 0.9995. 展开更多
关键词 Coastal Flooding Climate Change Sea level Rise elevation Global Warming GIS POPULATION Regression Analysis LOUISIANA
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Elevation of basal lacustrine sediments along the mid-lower reaches of the Yangtze River and its implications for the reconstruction of Holocene water levels
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作者 Shuchun YAO Chunhai LI Bin XUE 《Science China Earth Sciences》 SCIE EI CAS CSCD 2024年第9期2924-2936,共13页
The middle and lower reaches of the Yangtze River,a primary region for freshwater lakes in China,have undergone significant transformations throughout the Holocene.These changes,driven by factors such as sea-level ris... The middle and lower reaches of the Yangtze River,a primary region for freshwater lakes in China,have undergone significant transformations throughout the Holocene.These changes,driven by factors such as sea-level rise,climate change,and human activities,have led to the progressive elevation of water levels in this area.As a result,a floodplain has emerged,characterized by the formation of numerous shallow lakes along the river course.However,the pattern of water-level changes in the main channel of the Yangtze River during the Holocene remains unclear.This gap in knowledge poses challenges for understanding sediment transport dynamics,the interactions between the river and its adjacent lakes,and the prevention and control of flood disasters in the Yangtze River basin.To shed light on these issues,our study compiled data on the surface elevation and water depth of 81 lakes in the mid-lower reaches of the Yangtze River basin.Additionally,we analyzed historical water-level records from the 1900s to the 1970s at eight gauging stations from Shashi to Jiangyin along the river’s main stream.Our findings reveal that,particularly along the Jingjiang section,the basal elevation of most lakes is lower than the Yangtze River’s water level during the dry season.Conversely,the water level of the main stream exceeds that of both the floodplain and the lakes enclosed by the Jingjiang embankment.In the tidal reach,especially within the Taihu Lake basin,the basal elevation of lakes typically falls below sea level.Meanwhile,lakes located along the section from Chenglingji to Wuhu exhibit basal elevations that correspond with the Yangtze River’s annual average and dry season water levels.Given the widespread presence of lakes along the middle and lower reaches of the Yangtze River,our study introduces a new proxy for reconstructing the mean water level of the mid-lower Yangtze River in the Holocene.By analyzing sediments from Nanyi Lake and Chenyao Lake in the lower Yangtze River,we attempted to reconstruct the water level of the Yangtze River’s main channel since 8 ka BP. 展开更多
关键词 Middle and lower Yangtze River HOLOCENE Water level Floodplain lakes Basal sediment elevation
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The impact of sea-level rise on the coast of Tianjin-Hebei,China 被引量:16
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作者 Fu Wang Jian-fen Li +3 位作者 Pei-xin Shi Zhi-wen Shang Yong Li Hong Wang 《China Geology》 2019年第1期26-39,共14页
Bulletins of China's National Sea Level show that the average rising rate of sea-levels in China is 3.3 mm/a over the past 40 years, with an obviously accelerated rising trend in the last decade. The rate of relat... Bulletins of China's National Sea Level show that the average rising rate of sea-levels in China is 3.3 mm/a over the past 40 years, with an obviously accelerated rising trend in the last decade. The rate of relative sea-level rise of the Yangtze River Delta reached >10 mm/a after considering the land subsidence, and Bohai Bay is even greater than 25 mm/a. The impact of the sea level rise to the coastal area will be greater in the coming years, so carrying out an assessment of this rising trend is urgent. This paper, taking the coastal area of Tianjin and Hebei as examples, comprehensively evaluates the impact of sea-level rise through multitemporal remote sensing shoreline interpretation, ground survey verification, elevation measurements for both seawall and coastal lowlands. The results show that the average elevation of the measured coastal areas of Tianjin and Hebei is about +4 m, and the total area of >100 km^2 is already below the present mean sea level. More than 270 km, ca. 31% of the total length of the seawall, cannot withstand a 1-in-100-year storm surge. Numerical simulations of the storm flooding on the west coast of Bohai Bay, for 1-in-50-years, 1-in-100-years, 1-in-200-years and 1-in-500-years, show that if there were no coastal dykes, the maximum flooding area would exceed 3000 km^2, 4000 km^2, 5300 km^2 and 7200 km^2, respectively. The rising sea has a direct and potential impact on the coastal lowlands of Tianjin and Hebei. Based on the latest development in international sea-level rise prediction research, this paper proposes 0.5 m, 1.0 m and 1.5 m as low, middle and high sea level rise scenarios by 2100 for the study area, and combines the land subsidence and other factors to the elevation of the existing seawall. Comprehensive evaluation results indicate that even in the case of a low scenario, the existing seawall will not be able to withstand a 1-in-100-years storm surge in 2030, and the potential flooding areas predicted by the model will become a reality in the near future. Therefore, the seawall design in the coastal areas of Tianjin and Hebei must consider the combined effects of land subsidence, sea level rise and the extreme storm surges caused by it. 展开更多
关键词 Sea level RISE elevation SEAWALL SHORELINE Tianjin-Hebei (Jin-Ji) coast
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Adapting cities to sea level rise: A perspective from Chinese deltas 被引量:3
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作者 CHENG He-Qin CHEN Ji-Yu 《Advances in Climate Change Research》 SCIE CSCD 2017年第2期130-136,共7页
In recent years, intensifying waterlogging, salt water intrusion, wetland loss, and ecosystem degradation in Chinese delta cities and adjacent regions have generated the pressing need to create an urban form that is s... In recent years, intensifying waterlogging, salt water intrusion, wetland loss, and ecosystem degradation in Chinese delta cities and adjacent regions have generated the pressing need to create an urban form that is suited to both current and future climates incorporating sea level rise. However, adaptation planning uptake is slow. This is particularly unfortunate because patterns of urban form interact with mean sea level rise (MSLR) in ways that reduce or intensify its impact. There are currently two main barriers that are significant in arresting the implementation of adaptation planning with reference to the MSLR projections composed of geomorphologic MSLR projections and eustatic MSLR projections from global climate warming, and making a comprehensive risk assessment of MSLR projections. The present review shows recent progresses in mapping MSLR projections and their risk assessment approaches on Chinese delta cities, and then a perspective of adapting these cities to MSLR projections as following six aspects. 1) The geomorphologic MSLR projections are contributed by the natural tectonic subsidence projections and the MSLR projections by anthropogenic geomorphologic change. The former needs to be updated in a global framework. The latter is accumulated by land subsidence from underground water depletion, water level fall caused by the erosion of riverbeds from a sediment supply decline attributed to the construction of watershed dams, artificial sand excavation, water level raise by engineering projects including land reclamation, deep waterway regulation, and fresh water reservoirs. 2) Controlling MSLR projections by anthropogenic geomorphologic changes. 3) The IPCC AR5 RCPs MSLRs scenarios are expected to be projected to the local eustatic MSLR projections on the Chinese deltas. 4) The MSLR projections need to be matched to a local elevation datum. 5) Modeling approaches of regional river-sea numerical with semi- analytical hydrodynamics, estuarine channel network, system dynamics and adaptation points are perspective. 6) Adaptation planning to MSLR projections requires a comprehensive risk assessment of the risk of flood, fresh water supply shortage, coastal erosion, wetland loss, siltation of ports and waterway in Chinese delta cities and adjacent regions. 展开更多
关键词 Mean sea level rise projections Natural tectonic subsidence Climate warming Local elevation datum Anthropogenic geomorphologic change Adaptation tipping point
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Angle Dependence Analysis Method to Determine SNRArc Applied to GNSSMRSea Level Retrieval 被引量:6
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作者 Xiaolei WANG Xiufeng HE +2 位作者 Qin ZHANG Mingfeng SONG Zijin NIU 《Journal of Geodesy and Geoinformation Science》 2021年第2期14-26,共13页
The Global Navigation Satellite Systems(GNSS)broadcast radio signals are continuously at two or more frequencies in the L-band,and the multipath signals from sea surface recorded by off-the-shelf geodetic receivers ha... The Global Navigation Satellite Systems(GNSS)broadcast radio signals are continuously at two or more frequencies in the L-band,and the multipath signals from sea surface recorded by off-the-shelf geodetic receivers have been demonstrated they can be used to estimate sea level,using a technology called GNSS multipath reflectometry(GNSS-MR).Before proceeding to estimate reflection parameters,the azimuth range and elevation angle range are needed to be defined,as only with suitable azimuths and elevation angles the sensing zones can be guaranteed on water.So,this study presents an angle dependence analysis method to jointly select the azimuth range and elevation angle range based on wavelet analysis which can describe the nonstationary power of different sinusoidal oscillations changed with elevation angle.The key of this method is to use one grid model to screen the spectrum power of multipath oscillation on different elevation angles and azimuths in this work.Then the elevation angles and the azimuths can be determined by searching grids with greater power.The GPS and GLONASS data of two MultiGNSS Experiment(MGEX)stations named BRST and MAYG was analyzed and used to retrieve.Firstly,the angle dependence analysis was carried out to determine the elevation range and azimuth range.Secondly,the sea levels were retrieved from individual signals.Finally,the retrievals of individual signals are combined to form a 10-min sea level retrieval series.The RMSEs of the combined retrievals are both less than 15 cm.The results show the effectiveness of the selection of angle range based on the angle dependence analysis method. 展开更多
关键词 GNSS-MR sea level azimuth determination elevation angle determination multi-GNSS combination
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Validity of QRS Configuration and Myeloperoxidase Level as Determinants of CAD Severity and Prognosis in Patients with STEMI
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作者 Wael Ali Khalil Mohamed Abdou Abdelhamed Ahmed S. Eldamanhory 《World Journal of Cardiovascular Diseases》 2021年第1期82-97,共16页
<strong>Background:</strong><span style="font-family:Verdana;"> Terminal QRS distortion and fragmentation (fQRS) with elevated myeloperoxidase (MPO) were linked to poor cardiovascular outco... <strong>Background:</strong><span style="font-family:Verdana;"> Terminal QRS distortion and fragmentation (fQRS) with elevated myeloperoxidase (MPO) were linked to poor cardiovascular outcomes in acute coronary syndrome. We aimed to investigate these parameters in early prediction of coronary artery disease severity based on SYNTAX score and in-hospital adverse events in STEMI patients.</span><span style="font-family:Verdana;"> </span><b><span style="font-family:Verdana;">Methods:</span></b><span style="font-family:;" "=""><span style="font-family:Verdana;"> A total of 215 patients with first STEMI admitted for primary PCI were included in the study. They were divided according to the admission ECG into group I with QRS distortion or fQRS, group II with combined QRS distortion and fQRS, and group III without QRS distortion or fQRS. Myeloperoxidase and troponin I levels, ST resolution ratio, left ventricular EF%, and severity of coronary artery lesions using SYNTAX risk score were measured.</span><b><span style="font-family:Verdana;"> Results:</span></b><span style="font-family:Verdana;"> MPO level, SYNTAX score, and in-hospital mortality were higher in group I and II and were higher in group II compared to group I. By regression analysis, QRS distortion, fQRS, and MPO > 412 ng/ml were independent predictors of both CAD severity and in-hospital mortality. DM was an independent predictor of CAD severity (OR: 2.851, P 0.012) while high SYNTAX score was an independent predictor of in-hospital mortality (OR: 6.113, P 0.001). Adding MPO level to any QRS configuration pattern increased predictive value for the detection of CAD severity that was more evident in the combined QRS distortion and fragmentation. </span><b><span style="font-family:Verdana;">Conclusion: </span></b><span style="font-family:Verdana;">Terminal QRS distortion, fragmentation, or combined QRS distortion and fragmentation have a significant value in predicting in-hospital adverse events and CAD severity as assessed by SYNTAX score in association with plasma myeloperoxidase level in STEMI patients. Combined QRS distortion and fragmentation, in spite less common, could be more helpful for early risk stratification and management.</span></span> 展开更多
关键词 QRS Distortion QRS Fragmentation Myeloperoxidase level SYNTAX Score ST-elevation Myocardial Infarction
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摊铺机熨平装置的动力学建模与仿真分析
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作者 朱涛 孙健 李宏伟 《机械设计与制造》 北大核心 2024年第6期96-101,共6页
为了优化摊铺机熨平装置的设计参数,提供更好的施工操作策略,对摊铺机熨平装置进行了建模、仿真和实验。详述了摊铺厚度调整时仰角α变化的过程,对摊铺机熨平装置进行了受力分析,以仰角α为参数建立熨平装置的动力学模型。利用MATLAB搭... 为了优化摊铺机熨平装置的设计参数,提供更好的施工操作策略,对摊铺机熨平装置进行了建模、仿真和实验。详述了摊铺厚度调整时仰角α变化的过程,对摊铺机熨平装置进行了受力分析,以仰角α为参数建立熨平装置的动力学模型。利用MATLAB搭建Simulink框图,对动力学模型进行仿真,分析了熨平装置底板宽度、牵引点O与底板的垂直距离、重力G绕牵引点O的力臂大小对摊铺性能的影响。仿真与实验结果表明:所建立的动力学模型能够正确反映熨平装置的工作原理,增大熨平装置底板宽度可以提高找平系统的灵敏度,利用手动调节机构调整初始工作仰角可以有效规避负仰角出现而又不失灵敏性,输料、分料和行走系统要协同工作、相互匹配,保持料位高度恒定才能提高摊铺路面的平整度。 展开更多
关键词 摊铺机 熨平装置 动力学模型 仰角 找平系统
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基于双层规划的飞行区地势设计优化模型
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作者 袁捷 李一凡 +2 位作者 孟祥龙 张家科 彭逸洲 《同济大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第10期1551-1557,共7页
为设计出一个符合标准且成本最低的机场飞行区地势表面,在飞行区内划分出骨架和扭曲面,上层规划从全局角度确定骨架具体位置,下层规划根据上层规划的结果,以局部表面跟天然地面的拟合程度为目标,合理衔接骨架并使得扭曲面设计最优,形成... 为设计出一个符合标准且成本最低的机场飞行区地势表面,在飞行区内划分出骨架和扭曲面,上层规划从全局角度确定骨架具体位置,下层规划根据上层规划的结果,以局部表面跟天然地面的拟合程度为目标,合理衔接骨架并使得扭曲面设计最优,形成基于双层规划的飞行区地势设计优化模型,最后运用遗传算法求解。采用该模型计算得到的三明机场地势设计实例表明,优化模型的排水、坡度、坡段设计均符合既有要求,且与实际工程相比,更贴合天然地形,填方量下降7.50%,土方总计下降8.06%,工程成本降低10.73%。 展开更多
关键词 机场飞行区 地势设计 土方优化 双层规划 遗传算法
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省级高程基准数据处理方法实现及应用
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作者 陈建忠 赵中飞 +3 位作者 李晓红 张金营 朱伟 陈喆 《测绘通报》 CSCD 北大核心 2024年第S01期6-10,66,共6页
高程基准是测绘基准的主要内容之一,是新型基础测绘的重要组成部分。省级高程基准数据处理的方法虽然记载于相关规范中,但其具体实现还需要重力场模型、固体潮模型、海潮模型,以及太阳与月球位置模型等额外的数据模型,国内具备独立精密... 高程基准是测绘基准的主要内容之一,是新型基础测绘的重要组成部分。省级高程基准数据处理的方法虽然记载于相关规范中,但其具体实现还需要重力场模型、固体潮模型、海潮模型,以及太阳与月球位置模型等额外的数据模型,国内具备独立精密水准数据处理能力的单位较少。本文使用山东省重力场模型及部分开源公式、模型,开发了精密水准数据处理软件,经测试分析,该软件在水准概算、平差方面计算准确,具备了山东区域一、二等水准数据处理能力。同时,本文研究了一种以环闭合差评价实测数据、以实测数据评价起算点的平差方案设计方法,并成功应用于2023年山东省级高程基准动态监测项目中。 展开更多
关键词 高程基准 水准数据处理 平差方案
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深中通道沉管隧道碎石整平精度控制技术研究 被引量:2
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作者 夏丰勇 孙世鹏 +2 位作者 姚典 池明华 邓斌 《隧道建设(中英文)》 CSCD 北大核心 2024年第1期181-188,共8页
为了提高外海沉管隧道的基础处理精度与承载能力、减小沉管隧道的不均匀沉降,依托深中通道沉管隧道工程,介绍船架分离式整平船水下整平系统的组成、工作原理和适用条件,并分析影响整平精度的2个因素,即料斗口高程变化和料斗内碎石料高... 为了提高外海沉管隧道的基础处理精度与承载能力、减小沉管隧道的不均匀沉降,依托深中通道沉管隧道工程,介绍船架分离式整平船水下整平系统的组成、工作原理和适用条件,并分析影响整平精度的2个因素,即料斗口高程变化和料斗内碎石料高度控制;同时,结合ANSYS数值计算方法,分析水下大、小车轨道在自重情况下的变形,以及基架在不同工况组合下的变形,由此提出碎石整平系统精度控制技术,并采用接近式料位传感系统,实现料斗总成内碎石料位高度持续、实时监控和多点监测。该水下碎石整平系统精度控制技术在深中通道沉管隧道E32—E24管节碎石基础铺设中成功应用,其整平平均偏差为15.3 mm,可满足±40 mm的偏差设计要求,实现了设计要求的基础铺设精度控制目标。 展开更多
关键词 深中通道 沉管隧道 碎石基础铺设 水下碎石整平系统 整平精度 高程控制 高度监控
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基于北斗的超长距离跨河高程测量技术研究与实践 被引量:1
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作者 梁永 刘朝松 《测绘通报》 CSCD 北大核心 2024年第3期151-155,178,共6页
目前常用的跨河高程测量方法有水准测量、测距三角高程测量、GNSS测量。常规水准测量视距较短,测距三角高程测量对场地条件要求非常高,要求测点间相互通视并同步对向观测,测量精度受风力、大气折光、距离远近影响较大,随着测量距离的增... 目前常用的跨河高程测量方法有水准测量、测距三角高程测量、GNSS测量。常规水准测量视距较短,测距三角高程测量对场地条件要求非常高,要求测点间相互通视并同步对向观测,测量精度受风力、大气折光、距离远近影响较大,随着测量距离的增加,垂线偏差的影响也随之增大,导致精度降低。当跨距超过3500 m时,没有相关标准规范可以遵循,对于跨度10 km以上的超长距离跨河高程传递测量,更是一个较大的挑战。本文研究对超长距离跨江工程进行高程测量的方法。首先介绍基于北斗跨河水准测量方法的基本原理;然后以沪渝蓉高铁崇太过江隧道跨长江高程传递为例,阐述在跨河水准测量实施过程中水准控制网的布设方法、外业测量质量控制、数据处理及精度分析等。实践结果表明,在地势较平坦、高程异常变化率相对平缓的测区,通过布设强制观测墩、优化设计控制网网形、采用双测线跨河水准测量方法,内外符合精度指标均可满足二等水准测量要求。本文成功实现了10.2 km超长距离跨河水准测量技术在沪渝蓉高铁崇太过江隧道二等水准传递应用,对类似工程项目有很好的借鉴和参考意义。 展开更多
关键词 超长距离 跨河水准 高程异常变化率 二等水准测量
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“自由设站”法实现跨河水准测量技术分析与应用
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作者 曹年鹏 梅红 《测绘工程》 2024年第6期68-74,共7页
针对现有三角高程跨河水准精度较差、观测效率低下的问题,基于测距三角高程原理,经过严密的理论推导和研究,提出“自由设站”三角高程法进行跨河水准测量的方法,分析该观测方法的主要误差来源,该方法通过减少设站次数大幅度缩短观测时间... 针对现有三角高程跨河水准精度较差、观测效率低下的问题,基于测距三角高程原理,经过严密的理论推导和研究,提出“自由设站”三角高程法进行跨河水准测量的方法,分析该观测方法的主要误差来源,该方法通过减少设站次数大幅度缩短观测时间,观测过程中采用同时对向观测的方法削弱球气差的影响,经过实例的验证,表明“自由设站”三角高程法具有一定的可靠性和有效性,在保证精度的同时显著提高观测效率,成果满足国家二等水准测量的检核要求。 展开更多
关键词 跨河水准 精密三角高程 二等水准
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长距离跨海高程基准传递方法研究及广西北部湾工程验证
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作者 钟昌海 林自乐 +1 位作者 黄昕 孔建 《测绘通报》 CSCD 北大核心 2024年第2期161-164,182,共5页
针对陆海基准高程传递过程中传统方法的测量精度受海岛与陆地距离、陆海环境等因素的影响,对海域内的多个不连续岛屿进行测量时过程较为复杂的问题,本文提出了利用高精度似大地水准面进行高程传递的方法,研究了误差积累因素,给出了高程... 针对陆海基准高程传递过程中传统方法的测量精度受海岛与陆地距离、陆海环境等因素的影响,对海域内的多个不连续岛屿进行测量时过程较为复杂的问题,本文提出了利用高精度似大地水准面进行高程传递的方法,研究了误差积累因素,给出了高程传递的理论模型及具体的技术流程。在北部湾海域,利用该方法将1985国家高程基准由陆地传递到距离北海市40 km的涠洲岛和斜阳岛上,传递后GNSS水准点间的高程差与涠洲岛二等水准测量成果的独立高程差均优于±4.1 cm,为全国范围离岛高程传递工程提供了实践参考。 展开更多
关键词 长距离跨海高程传递 误差传播 似大地水准面 GNSS 水准测量
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城际铁路“桥建合一”车站车致振动特性及舒适度评价研究
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作者 鲁佩林 王凯 《建筑技术》 2024年第S01期123-127,共5页
以某城际铁路高架车站“竹料站”为背景,基于车辆-轨道-车站有限元动力仿真分析模型,对高架车站主体结构进行模态分析得到其各阶自振频率及振型特征;深入分析了列车正线到站、不同车速正线越行过站、不同车速正线会车过站工况下的高架... 以某城际铁路高架车站“竹料站”为背景,基于车辆-轨道-车站有限元动力仿真分析模型,对高架车站主体结构进行模态分析得到其各阶自振频率及振型特征;深入分析了列车正线到站、不同车速正线越行过站、不同车速正线会车过站工况下的高架车站车致振动特性;采用计权加速度均方根对不同行车工况下站厅层人体舒适度进行评价。 展开更多
关键词 城际铁路 桥建合一 高架车站 振动特性 舒适度
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