检索结果-南通市图书馆

Evaluation of the glacial isostatic adjustment(GIA) models for Antarctica based on GPS vertical velocities

Science China Earth Sciences 2020年第4期63卷 575-590页

作者： Fei LI Chao MA Shengkai ZHANG jintao lei Weifeng HAO Qingchuan ZHANG Wenhao LI Chinese Antarctic Center of Surveying and Mapping Wuhan UniversityWuhan 430079China

Due to the scarcity of data, modeling the glacial isostatic adjustment(GIA) for Antarctica is more difficult than it is for the ancient ice sheet area in North America and Northern Europe. Large uncertainties are observed in existing GIA models for Antarctica. Modern space-based geodetic measurements provide checks and constraints for GIA models. The present-day uplift velocities of global positioning system(GPS) stations at 73 stations in Antarctica and adjacent regions from 1996 to 2014 have been estimated using GAMIT/GLOBK version 10.5 with a colored noise model. To easily analyze the effect of difference sources on the vertical velocities, and for easy comparison with both GIA model predictions and GPS results from Argus et al.(2014) and Thomas et al.(2011), seven sub-regions are divided. They are the northern Antarctic Peninsula, the Filchner-Ronne Ice Shelf, the Amundsen Sea coast, the Ross Ice Shelf, Mount Erebus, inland Southwest Antarctica and the East Antarctic coast,respectively. The results show that the fast uplift in the north Antarctic Peninsula and Pine Island Bay regions may be caused by the elastic response to snow and ice mass loss. The fast subsidence near Mount Erebus may be related to the activity of a magma body. The uplift or subsidence near the East Antarctic coast is very slow while the uplift for the rest regions is mainly caused by GIA. By analyzing the correlation and the associated weighted root mean square(WRMS) between the GIA predictions and the GPS velocities, we found that the ICE-6G_C(VM5a) model and the Geruo 13 model show the most consistency with our GPS results, while the W12a and IJ05_R2 series models show poor consistency with our GPS results. Although improved greatly in recent years, the GIA modeling in Antarctica still lags behind the modeling of the North American. Some GPS stations, for example the Bennett Nunatak station(BENN), have observed large discrepancies between GIA predictions and GPS *** of the

关键词： Antarctica GPS Glacial isostatic adjustment Vertical velocity Uncertainty

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Crack identification in concrete, using digital image correlation and neural network

引用

Frontiers of Structural and Civil Engineering 2024年第4期18卷 536-550页

作者： Jingyi WANG Dong lei Kaiyang ZHOU jintao HE Feipeng ZHU Pengxiang BAI College of Mechanics and Materials Hohai UniversityNanjing 211100China

In engineering applications,concrete crack monitoring is very *** methods are of low efficiency,low accuracy,have poor timeliness,and are applicable in only a limited number of ***,more comprehensive detection of concrete damage under different scenarios is of high value for practical engineering *** image correlation(DIC)technology can provide a large amount of experimental data,and neural network(NN)can process very rich ***,NN,including convolutional neural networks(CNN)and back propagation neural networks(BP),can be combined with DIC technology to analyze experimental data of three-point bending of plain concrete and four-point bending of reinforced *** addition,strain parameters can be used for training,and displacement parameters can be added for comprehensive *** data obtained by DIC technology are grouped for training,and the recognition results of NN show that the combination of strain and displacement parameters,i.e.,the response of specimen surface and whole body,can make results more objective and *** identification results obtained by CNN and BP show that these technologies can accurately identify *** identification results for reinforced concrete specimens are less affected by noise than those of plain concrete *** is more convenient because it can identify some features directly from images,recognizing the cracks formed by macro *** can issue early warning of the microscopic cracks,but it requires a large amount of data and *** can be seen that CNN is more intuitive and efficient in image processing,and is suitable when low accuracy is adequate,while BP is suitable for occasions with greater accuracy *** two tools have advantages in different situations,and together they can play an important role in engineering monitoring.

关键词： digital image correlation convolutional neural network back propagation neural neural network damage detection concrete

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Slope-climbing of cropland and its effects in China

引用

Journal of Mountain Science 2024年第8期21卷 2754-2769页

作者： CHEN Wanxu XIE Youping YUAN jintao ZENG Jie YANG Liyan GU Tianci lei Fan Hubei Key Laboratory of Regional Ecology and Environmental Change School of Geography and Information EngineeringChina University of GeosciencesWuhan 430074China Key Laboratory of Natural Resources Monitoring and Supervision in Southern Hilly Region Ministry of Natural ResourcesChangsha 410118China Yunnan Key Laboratory of Plateau Geographic Processes and Environmental Changes Faculty of GeographyYunnan Normal UniversityKunming 650500China

In recent decades,the spatio-temporal patterns of China’s croplands have been reshaped by disturbances from anthropogenic activities,with complex changes in the topographic characteristics of ***-climbing of croplands(SCCL)is an important issue that threatens sustainable agricultural *** providing land with prominent location advantages,SCCL weakens the water and fertilizer retention capacity for cropland,intensifies various geological disasters,and adversely affects the ecological environment and food yield of these *** is crucial to determine the spatio-temporal variation features and effects of SCCL in China to formulate more accurate cropland protection policies and to maintain food security;however,the current lack of relevant studies is detrimental for capturing trends in cropland resources and sustainable cropland *** this study,we constructed a multi-scale slope spectrum for cropland and total terrain to explore the spatial differences and trends of SCCL from a three-dimensional *** evaluated the natural and socioeconomic effects of SCCL in China from multiple *** indicate that the proportion of cropland with slopes below 2°,5°,and 6°in China decreased by 0.43%,0.47%,and 0.50%from 1980 to 2020,*** became apparent during 1980-1990 and 2010-2020,especially over the recent *** cropland climbing index(CCI)and upper limited slope change(ULSC)to measure the spatio-temporal pattern of SCCL were 0.99%and 1.17°,respectively,during *** the agricultural regional scale,the SCCL was also concentrated in 1980-1990 and 2010-2020,and it is more pronounced in the southern *** proportion of provinces and prefecture-level cities with high-intensity SCCL during 1980-2020 were 87.10%and 49.73%,*** was comparatively more pronounced and broader from 2010 to *** this period,17.84%of prefecture-level cities had no SCCL,and the average CCI for all prefecture-level citi

关键词： Croplands Slope spectrum Slope-climbing Three-dimensional perspective Multi-scale China

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Self-powered stimuli responsive material for dual stimulation of heat and guest molecules

引用

Chinese Chemical Letters 2024年第2期35卷 590-593页

作者： jintao Men Ke Xu Taiting Sha lei He Yan Xu Jie Mu Tijian Yin Qiong Ye Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics and School of Chemistry and Chemical Engineering Southeast UniversityNanjing 211189China

Stimuli-responsive smart materials exhibit reverse chemical/physical changes in response to external stimuli and research on stimuli-responsive smart materials with self-powered properties is still uncultivated ***,we report perovskite crystalline self-powered multiple stimuli-responsive materials triggered by chemical and thermal stimuli.[HMEP]PbI_(3)·(H_(2)O)(1;HMEP is a hydroxytris(1-methylethyl)phosphorus cation)crystallizes in a chiral space group P 21 at 293 K and has the piezoelectric reaction(d_(33)=10 pC/N and output voltage=1 V)of self-powered modes,this value is larger than the value of 3 pC/N for the classical piezoelectric material *** materials can generate energy due to mechanical deformation,and using thermal heating to lose water,[HMEP]PbI_(3)(2)can be obtained.2 crystallizes in the non-centrosymmetric space group,undergoes two reversible phase transitions at 243/255 K and 315/348 K,and shows second harmonic generation ***,2 can return to the hydrated form 1 after absorbing *** work will lay the foundation for self-powered stimuli-responsive compounds and contribute to the construction of novel organic-inorganic hybrid materials with second harmonic generation switching.

关键词： Self-powered Dual stimulation reactive Phase transition SHG switch Organic-inorganic hybrid perovskite

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

山地城市内涝形成机理及管理策略研究

引用

重庆建筑 2024年第7期23卷 5-9页

作者：马念徐永新吴欢魏静婉李书钺雷锦涛韩璐明仆林同棪国际工程咨询<中国>有限公司重庆401121 西开普大学自然科学学院地球科学系南非开普敦7535

城市化改变了区域水文过程,涉及城市内涝的水安全问题成为城市普遍面临的挑战。该文以城市化水文效应和排水系统替代模型为基础研究了山地城市内涝机理和成因,在此基础上提出了城市内涝管理的总体策略。城市化后安全要求提高而人工的排... 详细信息

城市化改变了区域水文过程,涉及城市内涝的水安全问题成为城市普遍面临的挑战。该文以城市化水文效应和排水系统替代模型为基础研究了山地城市内涝机理和成因,在此基础上提出了城市内涝管理的总体策略。城市化后安全要求提高而人工的排水系统并不能完全替代原有的泄流通道,这一矛盾是城市内涝产生的根源;为管理等级有序的城市雨洪系统,需要根据系统构成、功能定位和等级制定与之相适应的技术标准,采取相适应的技术措施;雨洪管理需要防御性和适应性相结合,同时利用工程措施和非工程管理措施,并引入智慧管理手段以提高城市洪涝韧性。

关键词：山地城市城市内涝城市化水文效应排水系统替代模型形成机理内涝管理城市韧性

来源：

维普期刊数据库博看期刊

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Experimental Investigation on Condensate Revaporization During Gas Injection Development in Fractured Gas Condensate Reservoirs

引用

哈尔滨工程大学学报（英文版） 2024年第3期23卷 575-582页

作者： lei Zhang Yingxu He jintao Wu Haojun Wu lei Huang Linna Sun Bohai Oilfield Research Institute Tianjin Branch of CNOOCTianjin 300459China

The gas field in the Bohai Bay Basin is a fractured metamorphic buried-hill reservoir with dual-media characteristics. The retrograde vaporization mechanism observed in this type of gas condensate reservoir differs significantly from that observed in sand gas condensate reservoirs. However, studies on improving the recovery of fractured gas condensate reservoirs are limited;thus, the impact of retrograde vaporization on condensate within fractured metamorphic buried-hill reservoirs remains unclear. To address this gap, a series of gas injection experiments are conducted in pressure-volume-temperature(PVT) cells and long-cores to investigate the retrograde vaporization effect of condensate using different gas injection media in fractured gas condensate reservoirs. We analyze the variation in condensate volume, gas-to-oil ratio, and condensate recovery during gas injection and examine the influence of various gas injection media(CO_(2), N_(2), and dry gas) under different reservoir properties and varying gas injection times. The results demonstrate that the exchange of components between injected gas and condensate significantly influences condensate retrograde vaporization in the formation. Compared with dry gas injection and N_(2) injection,CO_(2) injection exhibits a superior retrograde vaporization effect. At a CO_(2) injection volume of 1 PV, the percentage shrinkage volume of condensate is 13.82%. Additionally, at the maximum retrograde condensation pressure, CO_(2) injection can increase the recovery of condensate by 22.4%. However, the condensate recovery is notably lower in fractured gas condensate reservoirs than in homogeneous reservoirs, owing to the creation of dominant gas channeling by fractures, which leads to decreased condensate recovery. Regarding gas injection timing, the effect of gas injection at reservoir pressure on improving condensate recovery is superior to that of gas injection at the maximum retrograde condensation pressure. This research

关键词： Buried-hill fractured reservoir Gas condensate reservoir Retrograde condensation CO_(2)injection Retrograde vaporization

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

不同海潮模型对东南极沿海地区GPS基线解算的影响

引用

武汉大学学报（信息科学版） 2015年第11期40卷 1479-1486页

作者：雷锦韬李斐张胜凯马超武汉大学中国南极测绘研究中心湖北武汉430079 武汉大学测绘遥感信息工程国家重点实验室湖北武汉430079

在高精度GPS数据处理中,海潮的影响是一个不可忽略的因素。利用GAMIT软件解算2011年东南极沿海地区中国中山站及其周边6个IGS站的GPS数据,对比分析了FES2004、DTU10、EOT11a、GOT4.7、HAMTIDE11a、OSU12以及TPXO7.2等7个全球海潮模型在... 详细信息

在高精度GPS数据处理中,海潮的影响是一个不可忽略的因素。利用GAMIT软件解算2011年东南极沿海地区中国中山站及其周边6个IGS站的GPS数据,对比分析了FES2004、DTU10、EOT11a、GOT4.7、HAMTIDE11a、OSU12以及TPXO7.2等7个全球海潮模型在不同测站的海潮负荷差异,比较了海潮负荷对于GPS基线解的影响。结果表明,海潮负荷对GPS基线解的影响与测站所处位置及基线方位有关,达到cm级,相对影响达到10-8,因此,在高精度的GPS基线解算中必须考虑海潮的影响;但选用不同海潮模型对东南极沿海地区GPS基线解算的差异可忽略不计。

关键词：南极海潮模型 GPS 基线解算

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Analysis of GPS Time Series Based on Spatio-temporal Filtering in Antarctic Peninsula

Analysis of GPS Time Series Based on Spatio-temporal Filteri...

引用

第九届中国卫星导航学术年会

作者： Wenhao Li Fei Li Shengkai Zhang jintao lei Qingchuan Zhang Chinese Antarctic Center of Surveying and Mapping

The high-accuracy GPS velocity field is one of effective approaches to study the regional crustal displacement, and can provide validations and constraints for GIA models. There are spatially and temporally correlated errors in GPS data. Applying a spatiotemporal filter can reduce these effects and improve the accuracy of GPS time series. To obtain high-accuracy GPS vertical velocities in Antarctic peninsula, a "regional filter" is used to remove the spatially correlated errors in the selected 6 GPS time series, and the classic autocorrelation function is used to mitigate the temporally correlated errors of each GPS time series. The result shows that the scatter of GPS time series is reduced significantly after spatiotemporal filtering, the reduction of maximum RMS can reach up to 41.82%, and mean RMS reduction is 35.44%.

关键词： Antarctic Peninsula GPS vertical velocities spatiotemporal filtering common mode errors

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

全球海潮模型研究进展

引用

地球科学进展 2015年第5期30卷 579-588页

作者：张胜凯雷锦韬李斐中国南极测绘研究中心武汉大学湖北武汉430079 测绘遥感信息工程国家重点实验室武汉大学湖北武汉430079

阐述潮汐分析方法和建模方法,归纳总结了FES,CSR,GOT,NAO,TPXO,EOT,DTU,HAMTIDE及OSU系列全球海潮模型的建立机构、使用数据及构建方法等。对比分析2010年后出现的几种新的海潮模型(FES2012,EOT11a,DTU10和HAMTIDE11a)在南大洋的M2振幅... 详细信息

阐述潮汐分析方法和建模方法,归纳总结了FES,CSR,GOT,NAO,TPXO,EOT,DTU,HAMTIDE及OSU系列全球海潮模型的建立机构、使用数据及构建方法等。对比分析2010年后出现的几种新的海潮模型(FES2012,EOT11a,DTU10和HAMTIDE11a)在南大洋的M2振幅,发现模型间差异主要集中在浅水及极地地区,其中极地地区高精度卫星测高数据的缺少及海冰的季节性变化,是导致建模精度较差的主要原因。最后对海潮模型的发展方向提出一些建议。

关键词：卫星测高验潮站潮汐分析海潮模型南极

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

一种基于LSTM-Blacklist的动态信任度证明机制

引用

武汉大学学报（理学版） 2023年第2期69卷 156-168页

作者：徐超雷锦涛陈勇南京审计大学计算机学院江苏南京211815

针对区块链网络中共识节点的恶意行为导致的区块链系统安全问题,提出一种基于LSTM(long short-term memory)-Blacklist的动态信任度证明机制(PoDT-LSTMB)。该动态信任度证明机制通过前向注意力机制的两层LSTM神经网络学习并分析参与共... 详细信息

针对区块链网络中共识节点的恶意行为导致的区块链系统安全问题,提出一种基于LSTM(long short-term memory)-Blacklist的动态信任度证明机制(PoDT-LSTMB)。该动态信任度证明机制通过前向注意力机制的两层LSTM神经网络学习并分析参与共识节点的行为数据,预测节点行为倾向。以节点信任度为基础构建黑名单,剔除低于信任度阈值的节点,提高全网节点的总体可信性。以正常区块上链率以及节点信任度的变化为主要评估指标,与信任度证明PoT(Proof of Trust)机制以及不带黑名单的PoDT-LSTM机制进行了对比实验。实验结果表明,基于前向注意力机制的两层LSTM神经网络结构准确率可达0.9151,本文提出的PoDT-LSTMB机制比PoT机制的正常区块上链率提高30%~33%。

关键词：区块链共识机制动态信任度长短期记忆黑名单机制

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：