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3D Woven Structures and Their Weave Design with Changing Cross-section on Warp and Weft Direction
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作者 祝成炎 《Journal of Donghua University(English Edition)》 EI CAS 2004年第6期71-75,共5页
With 3D orthogonal and pseudo-orthogonal weaves, woven sructures with lengthwise and widthwise changing cross section on one side or both sides of the structure can be constructed. The weave formation and the looming ... With 3D orthogonal and pseudo-orthogonal weaves, woven sructures with lengthwise and widthwise changing cross section on one side or both sides of the structure can be constructed. The weave formation and the looming draft creation are discussed in this paper which can be used as references to manufacture woven preforms with changing cross sections. 展开更多
关键词 3D ORTHOGONAL weave pseudo-orthogonal weave woven structure changing cross-section woven PREFORM
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Simulating cross-sectional geometry of the main channel in response to changes in water and sediment in Lower Yellow River 被引量:7
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作者 WANG Yanjun WU Baosheng ZHONG Deyu 《Journal of Geographical Sciences》 SCIE CSCD 2020年第12期2033-2052,共20页
To understand the non-equilibrium morphological adjustment of a river in response to environmental changes,it is essential to(i)accurately identify how past conditions of water and sediment have impacted current morph... To understand the non-equilibrium morphological adjustment of a river in response to environmental changes,it is essential to(i)accurately identify how past conditions of water and sediment have impacted current morphological adjustment of the river,and(ii)establish a corresponding simulation for non-equilibrium conditions.Based on discharge and suspended sediment concentration(SSC)as well as 82 cross-sectional data items for the Huayuankou-Lijin reach of the Lower Yellow River in the period 1965-2015,the process of adjustment of the geometry of the main channel(area,width,depth,and geomorphic coefficient),and its responses to changes in discharge and SSC for different reaches are statistically analyzed.Following this,a delayed response model(DRM)of the geometry of the main channel subjected to variations in discharge and SSC is established using a multi-step analytical model,with the discharge and SSC as the main controlling factors.The results show that the area,width,and depth of the main channel decreased initially,then increased,decreased again,and finally increased again.These features of the geometry of the channel were positively correlated with the 4-year moving average discharge and negatively with the 4-year moving average SSC.The geomorphic coefficient for the Huayuankou-Sunkou reach exhibited a trend of decrease,whereas that of the Sunkou-Lijin reach decreased initially,then increased,decreased again,and finally increased again.Except for the Huayuankou-Gaocun reach in 1965-1999,the coefficient was negatively correlated with the 4-year moving average discharge and positively with SSC.The simulated values of the morphological parameters of the main channel for all sub-reaches obtained using the DRM agreed well with the measured values.This indicates that the DRM can be used to simulate the process of response of the cross-sectional geometry of the main channel to variations in the water and sediment.The results of the model show that the adjustment of the geometry of the main channel was affected by the discharge and the SSC at present(30%)as well as for the previous 7 years(70%).The proposed model offers insights into the mechanism whereby past water and sediment influence the current morphological adjustment of the river,and provides an effective method for predicting the magnitude and trend of the geometry of the main channel under different flow conditions. 展开更多
关键词 Lower Yellow River water and sediment changes cross-sectional geometry of the main channel delayed response model
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Effect of Accumulative Strain on Grain Refinement and Strengthening of ZM6 Magnesium Alloy During Continuous Variable Cross-Section Direct Extrusion 被引量:3
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作者 Feng Li Wei Shi +1 位作者 Nan Bian Hong-Bin Wu 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2015年第5期649-655,共7页
In order to study the influence of die combination on continuous variable cross-section direct extrusion (CVCDE) in the extrusion process, the accumulative strain formula is derived, and it can be known that the ext... In order to study the influence of die combination on continuous variable cross-section direct extrusion (CVCDE) in the extrusion process, the accumulative strain formula is derived, and it can be known that the extrusion ratio of various stages directly determines the size of corresponding stage strain by formula. In this paper, as an example of the two interim dies, three die combinations of different angles and extrusion ratio are designed. Aviation magnesium alloy ZM6 is studied, and the results show that dynamic recrystallization is even more complete when continuous shear deformation occurs, so that the refinement and homogenization of microstructure are obtained. By the use of different die combinations, the accumulative strain increases under the conditions of same total extrusion ratio. Thus, the refined crystalline strengthening effect of extrusion deformation can be further analyzed. Due to the dead-zone defects, the actual accumulative strain decreases significantly and the effect of microstructure and performance improvements also decreases with it. Therefore, the optimal design of die combination is the key to the process and product of CVCDE, which provides a scientific basis for the development of severe plastic deformation. 展开更多
关键词 continuous variable cross-section direct extrusion (CVCDE) Die combination Accumulative strain Magnesium alloys Severe plastic deformation
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Microstructural characteristics and deformation of magnesium alloy AZ31 produced by continuous variable cross-section direct extrusion 被引量:1
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作者 Hongwei Jiang Feng Li Xiang Zeng 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2017年第6期573-579,共7页
Magnesium(Mg) alloy AZ31 was produced by continuous variable cross-section direct extrusion(CVCDE)to study its deformation behavior. Metallographic microscopy(OM), transmission electron microscopy(TEM), and sc... Magnesium(Mg) alloy AZ31 was produced by continuous variable cross-section direct extrusion(CVCDE)to study its deformation behavior. Metallographic microscopy(OM), transmission electron microscopy(TEM), and scanning electron microscopy(SEM) were used to observe the variations in microstructure and fracture morphology of Mg alloy AZ31 as a function of processing methods. The results reveal that grains of Mg alloy AZ31 were refined and their microstructure was homogenized by CVCDE. The recrystallization in Mg alloy AZ31 produced by CVCDE with 2 interim dies was more complete than that produced by conventional extrusion(CE) and CVCDE with 1 interim die, and the grains were finer and more uniform.Plasticity of the AZ31 alloy was improved. Fracture mode was evolved from a combination of ductility and brittleness to a sole ductile form. In summary, a CVCDE mold structure with 2 interim dies can improve microstructure, plasticity, and toughness of Mg alloy AZ31. 展开更多
关键词 continuous variable cross-section direct extrusion(CVCDE) Magnesium alloys Microstructural characteristics Plastic deformation
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Change in and continuity of traditional village architecture:the Bali Aga village of Tenganan Pegringsingan,Bali,Indonesia
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作者 Dwita Hadi Rahmi 《Built Heritage》 2025年第4期185-202,共18页
Traditional architecture is a cultural expression of a community that has developed from time to time with changes in and continuity of its cultural values.There are cultural values that remain stable and can still su... Traditional architecture is a cultural expression of a community that has developed from time to time with changes in and continuity of its cultural values.There are cultural values that remain stable and can still survive in contemporary culture,whereas others change following the socio-cultural development of the community.There needs to be a balance between the change in and continuity of cultural values to achieve the sustainability of traditional architecture.Balance can be achieved if the core of its heritage,which is the cultural values of the community,is maintained and if the heritage values of old cultural products can be appreciated in contemporary culture.Tenganan Pegringsingan Village,a traditional Bali Aga village,has developed into a cultural tourism village.Most of its residents are involved in tourism activities,having opened art shops in their houses and selling crafts in the open spaces of the village.Problems arise when changes in the architecture of the village and residents'houses,regarding which there is fear that they will affect the sustainability of residents'traditional cultural values,increase.This study aims to examine the changes in and continuity of traditional architecture in the Tenganan Pegringsingan Village settlement.It observed the village and spatial layout of houses,conducted in-depth interviews with homeowners and village leaders,and was supported by data from questionnaires.Qualitative analysis was carried out,supported by maps,photos,and architectural drawings.This study revealed that there are changes in four elements of village architecture due to tourism,including village spatial design,the function and design of awangan(open space),the function and layout of houses,and building façades.The intervention of the government and the involvement of the community in tourism activities for economic interests have triggered many changes.However,the continuity of these components still exists because the village community continues to strongly hold traditional rules.Tenganan Pegringsingan Village is under threat due to the decline of its architectural continuity,which will obscure and degrade the cultural values of its heritage.The balance between the change in and continuity of the elements of village spatial design and houses,which is strongly influenced by the dynamics of the community's cultural life,is the novelty of this architectural research. 展开更多
关键词 ARCHITECTURE changE continuITY Tenganan Pegringsingan Traditional village
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Near real-time monitoring of carbon effects from continuous forest change in rapidly urbanizing region of China from 2000 to 2020
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作者 Dou Zhang Xiaojing Tang +5 位作者 Shuaizhi Lu Xiaolei Geng Zhaowu Yu Yujing Xie Si Peng Xiangrong Wang 《Forest Ecosystems》 2025年第4期688-700,共13页
Forest carbon sinks are crucial for mitigating urban climate change.Their effectiveness depends on the balance between gross carbon losses and gains.However,quantitative and continuous monitoring of forest change/dist... Forest carbon sinks are crucial for mitigating urban climate change.Their effectiveness depends on the balance between gross carbon losses and gains.However,quantitative and continuous monitoring of forest change/disturbance carbon fluxes is still insufficient.To address this gap,we integrated an improved spatial carbon bookkeeping(SBK)model with the continuous change detection and classification(CCDC)algorithm,long-term Landsat observations,and ground measurements to track carbon emissions,uptakes,and net changes from forest cover changes in the Yangtze River Delta(YRD)of China from 2000 to 2020.The SBK model was refined by incorporating heterogeneous carbon response functions.Our results reveal that carbon emissions(-3.88 Tg C·year^(-1))were four times greater than carbon uptakes(0.93 Tg C·year^(-1))from forest cover changes in the YRD during 2000-2020,despite a net forest cover gain of 10.95×10^(4) ha.These findings indicate that the carbon effect per hectare of forest cover loss is approximately 4.5 times that of forest cover gain.The asymmetric carbon effect suggests that forest cover change may act as a carbon source even with net-zero or net-positive forest cover change.Furthermore,carbon uptakes from forest gains in the YRD during 2000-2020 could only offset 0.28% of energy-related carbon emissions from 2000 to 2019.Urban and agricultural expansions accounted for 37% and 10% of carbon emissions,respectively,while the Grain for Green Project contributed to 45% of carbon uptakes.Our findings underscore the necessity of understanding the asymmetric carbon effects of forest cover loss and gain to accurately assess the capacity of forest carbon sinks. 展开更多
关键词 continuous forest cover change Asymmetric carbon effects continuous change detection and classification(CCDC)algorithm Improved spatial carbon bookkeeping(SBK)model Google Earth Engine(GEE)
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Cross-sectional study of the educational background and trauma knowledge of trainees in the “China trauma care training” program 被引量:8
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作者 Hao Tang Dong Liu +5 位作者 Dong Yang Jia-Xin Tan Xiu-Zhu Zhang Xiang-Jun Bai Mao Zhang Lian-Yang Zhang 《Military Medical Research》 SCIE CAS CSCD 2020年第1期44-54,共11页
Background:Since the trauma knowledge of trauma providers correlates with the outcomes of injured patients,this study aims to assess the socio-demographic characteristics and levels of trauma knowledge of trainees in ... Background:Since the trauma knowledge of trauma providers correlates with the outcomes of injured patients,this study aims to assess the socio-demographic characteristics and levels of trauma knowledge of trainees in the China trauma care training(CTCT)program in addition to their post-course test results to provide support for the development of trauma care training programs and trauma systems in China.Methods:A cross-sectional study was conducted by collecting demographic information,hospital-related information and trauma knowledge of the trainees from 19 regions in China.All participants were assessed by questionnaires collecting the socio-demographic data,the trauma care knowledge levels and the information of the hospitals.Results:There were 955 males(78.9%)and 256 females(21.1%)enrolled.Among them,854 were physicians(70.5%),357 were registered nurses(29.5%).In addition,64 of them also played an administrative role in the hospitals(5.3%).The score of the trainees who were members of the emergency department staff(72.59±14.13)was the highest among the scores of all the personnel surveyed,followed by those of the trainees from the intensive care unit(ICU)(71.17±12.72),trauma surgery department(67.26±13.81),orthopedics department(70.36±14.48),general surgery department(69.91±14.79)and other departments(69.93±16.91),P=0.031.The score of the professors(73.09±15.05)was higher than those of the associate professors(72.40±14.71),lecturers(70.07±14.25)and teaching assistants(67.58±15.16),P<0.0001.The score of the individuals who attended experts’trauma lectures(72.22±14.45)was higher than that of individuals who did not attend the lectures(69.33±15.17),P=0.001.The mean scores before and after the training were 71.02±14.82 and 84.24±13.77,respectively,P<0.001.The mean score of trauma knowledge after the training of trainees from different provinces and with different educational backgrounds was higher than that before the training,with a statistically significant difference(P<0.05).Conclusions:The level of trauma knowledge of trauma care providers was associated with their department,professional position and previous participation in related academic conferences.Trauma care experience and participation in academic lectures and training program including CTCT may effectively improve individuals’level of trauma knowledge. 展开更多
关键词 cross-sectional study Trauma care knowledge Educational background continuing medical education
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THE TEMPERATURE ANALYSIS OF THE BILLET WITH PHASE CHANGE DURING CONTINUOUS CASTING
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作者 赵兴华 陈小弟 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1994年第2期109-118,共10页
In this paper,the problem of 3-D steady heat conduction including the influenceof phase change on billets is turned into the 2-D transient problem by a suitable transformation technique. The effective specific heat ha... In this paper,the problem of 3-D steady heat conduction including the influenceof phase change on billets is turned into the 2-D transient problem by a suitable transformation technique. The effective specific heat has been employed to substitutefor the effect of the phase ceange.The computational formulation of finite element has been presented. And the careful disposal of the phase change region has also beengiven. 展开更多
关键词 continuous casting.phase change.temperature field
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STREAMLINING EFFORTS BRING CHANGES TO OFFICE MISSIONS (CONTINUED)
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《Bulletin of the Chinese Academy of Sciences》 1999年第3期195-197,共3页
The Bureau of High-Technology Research and Development (BHRD) BHRD is in charge of management for the research and; development activities in high-technology areas in CAS, including predicting the trends of high-techn... The Bureau of High-Technology Research and Development (BHRD) BHRD is in charge of management for the research and; development activities in high-technology areas in CAS, including predicting the trends of high-technology development in the light of the demands for technology which is strategic, forward- 展开更多
关键词 CAS STREAMLINING EFFORTS BRING changES TO OFFICE MISSIONS continuED high
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兼顾拖拉机旋耕机组综合性能的变速控制策略
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作者 尚连锋 王宁宁 +1 位作者 张明柱 周思康 《农机化研究》 北大核心 2026年第6期244-252,共9页
针对液压机械无级变速拖拉机旋耕作业时的控制策略问题,采用负载双输入的后向建模方法,分析机组功率传递特性,并逐一对旋耕机、拖拉机行走系统、液压机械无级变速器(Hydro-Mechanical Continuously Variable Transmission,HMCVT)传动特... 针对液压机械无级变速拖拉机旋耕作业时的控制策略问题,采用负载双输入的后向建模方法,分析机组功率传递特性,并逐一对旋耕机、拖拉机行走系统、液压机械无级变速器(Hydro-Mechanical Continuously Variable Transmission,HMCVT)传动特性、发动机燃油特性与调速特性进行建模分析,建立了拖拉机旋耕机组动力学模型。通过单位作业量油耗评估机组的燃油经济性可知,增大前进速度能提升机组生产率和燃油经济性。为此,提出了发动机与HMCVT二元协同调控下机组最佳生产率—燃油经济性与作业质量,二者变速比加权的综合变速控制策略,以及负载反馈控制原理。同时,采用参数循环算法求解HMCVT目标变速比与稳定发动机转速所需的油门开度。结果表明:该变速控制策略可以按照驾驶员选取的加权系数调节机组前进速度,使发动机稳定在目标转速,实现旋耕速比连续变换,机组能够更好地适应土壤环境,并充分发挥最佳性能。 展开更多
关键词 拖拉机旋耕机组 液压机械无级变速器 燃油经济性 无级变速控制策略
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连续变截面超大断面明挖隧道衬砌施工技术
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作者 苏昌辉 郑伟 +2 位作者 刘飞 张乾海 张俊儒 《建筑技术开发》 2026年第2期47-49,共3页
研究以新建广州至湛江高速铁路珠三角枢纽机场段广湛机场2号隧道为工程背景,聚焦连续变截面明挖隧道衬砌的施工技术难点,围绕外模衬砌台车的通用性设计与施工适应性进行系统研究。通过结构参数优化与通用转换机制设计,实现单台台车在Ⅰ... 研究以新建广州至湛江高速铁路珠三角枢纽机场段广湛机场2号隧道为工程背景,聚焦连续变截面明挖隧道衬砌的施工技术难点,围绕外模衬砌台车的通用性设计与施工适应性进行系统研究。通过结构参数优化与通用转换机制设计,实现单台台车在Ⅰ型(1.3 m厚)与Ⅱ型(1.1 m厚)衬砌断面间的高效切换。台车行走系统采用液压升降与滚动摩擦结合的驱动模式,有效提高行走效率与施工安全性。结合现场地质条件与荷载计算,设计台车专用混凝土行走平台,并验证其结构承载能力。通过全过程质量控制体系保障衬砌精度和施工安全,验证了该通用性施工方案在连续变截面大断面隧道中的适应性。 展开更多
关键词 连续变截面 超大断面隧道 明挖法 外模衬砌台车
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Analysis of the Maximum Continuous Precipitation Variation in Shenyang in 48 Years 被引量:1
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作者 方晓 高锋 《Meteorological and Environmental Research》 CAS 2010年第12期35-37,共3页
[Objective] The aim was to study the changes of maximum continuous precipitation in Shenyang in recent 48 years.[Method] By dint of the daily precipitation from May to September from 1961 to 2008 and according to simp... [Objective] The aim was to study the changes of maximum continuous precipitation in Shenyang in recent 48 years.[Method] By dint of the daily precipitation from May to September from 1961 to 2008 and according to simple linear trend estimates and microwave analysis,the maximum consecutive precipitation in each month was analyzed.[Result] The frequency of extreme value for the maximum consecutive precipitation in Shenyang increased since 1990.The decreasing trend of maximum consecutive precipitation from May to September was consistent with that around 1990.The decrease of maximum consecutive precipitation amount had tendency to decrease along with the passing of time.There was 5 years temporal scale period of maximum consecutive precipitation from May to September in Shenyang.Maximum value occurred in 1973 and the minimum value occurred in 2000.[Conclusion] The study had important reality meaning to the understanding of climate changes in Shenyang and disaster prevention and relief work of extreme climate incidents. 展开更多
关键词 Shenyang Maximum continuous Precipitation change Analysis China
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温变条件下纤维增强复材加固混凝土连续梁徐变效应分析
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作者 王智慧 蒋文 鲁巧稚 《粘接》 2026年第1期89-93,共5页
研究温变条件下纤维增强复合材料对加固混凝土大跨度连续梁徐变效应的影响,以提升桥梁结构的稳定性。采用碳纤维布作为纤维增强复合材料,通过不同加固方式制作加固混凝土梁样品,并测试温度骤降、冻融循环、持续高温等环境条件进行测试... 研究温变条件下纤维增强复合材料对加固混凝土大跨度连续梁徐变效应的影响,以提升桥梁结构的稳定性。采用碳纤维布作为纤维增强复合材料,通过不同加固方式制作加固混凝土梁样品,并测试温度骤降、冻融循环、持续高温等环境条件进行测试分析。试验结果显示,试验组3中沿着样品纵向方向粘贴两层碳纤维布,再沿着试件横向方向,以“U”形形态粘贴一层碳纤维布,在温度骤降以及冻融循环时的应力值更大,徐变系数更大,持续高温对加固后的混凝土梁影响较小,试验组3加固下碳纤维布的厚度为6 mm时,该混凝土梁展现出更良好的徐变效应。 展开更多
关键词 温变条件 纤维增强 加固混凝土 大跨度 连续梁 徐变效应
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Dynamic changes of behaviors, dentate gyrus neurogenesis and hippocampal miR-124 expression in rats with depression induced by chronic unpredictable mild stress 被引量:15
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作者 Yun-Ling Huang Ning-Xi Zeng +5 位作者 Jie Chen Jie Niu Wu-Long Luo Ping Liu Can Yan Li-Li Wu 《Neural Regeneration Research》 SCIE CAS CSCD 2020年第6期1150-1159,共10页
The depression-like behavior phenotype,neurogenesis in the dentate gyrus and miR-124 expression in the hippocampus are the focus of current research on the pathogenesis of depression and antidepressant therapy.The pre... The depression-like behavior phenotype,neurogenesis in the dentate gyrus and miR-124 expression in the hippocampus are the focus of current research on the pathogenesis of depression and antidepressant therapy.The present study aimed to clarify the dynamic changes of depression-like behavior,dentate gyrus neurogenesis and hippocampal miR-124 expression during depression induced by chronic stress to reveal pathological features at different stages of depression and to further provide insight into depression treatment.Chronic unpredictable mild stress depression models were established by exposing Sprague-Dawley rats to various mild stressors,including white noise,thermal swimming,stroboscopic illumination,soiled cages,pairing with three other stressed animals,cold swimming,tail pinch,restraint and water and food deprivation.Chronic unpredictable mild stress model rats underwent dynamic observation from 1 to 8 weeks and were compared with a control group(normal feeding without any stressors).To observe changes in the depression-like behavior phenotype during chronic unpredictable mild stress-induced depression,a sucrose preference test was used to evaluate the degree of anhedonia.An open-field test was used to evaluate locomotor activity and anxiety status.Compared with the control group,chronic unpredictable mild stress rats lost weight but did not have a depression-like behavioral phenotype at 1-4 weeks.Chronic unpredictable mild stress rats presented decreased sucrose preference and locomotor activity at 5-8 weeks.In addition,chronic unpredictable mild stress rats did not have significant anxiety-like behavior during 1-8 weeks of modeling.To observe neurogenesis dysfunctions and changes in neuronal number in the dentate gyrus during chronic unpredictable mild stress-induced depression,markers(DCX and DCX/BrdU)of neural proliferation and differentiation and the neuronal marker NeuN were assessed by immunofluorescence.Compared with the control group,neurogenesis and the neuronal number in the dentate gyrus did not change from 2 to 6 weeks;however,neural proliferation and differentiation in the dentate gyrus decreased,and the number of neurons decreased until the eighth week in the chronic unpredictable mild stress group.Real-time quantitative reverse transcription polymerase chain reaction assays and fluorescence in situ hybridization were used to measure the expression of hippocampal miR-124 during chronic unpredictable mild stress-induced depression.The results showed that the expression of hippocampal miR-124 was unchanged during the first 4 weeks but increased from 5 to 6 weeks and decreased from 7 to 8 weeks compared with the control group.These findings indicate that during chronic unpredictable mild stress-induced depression,the behavioral phenotype,miR-124 expression in the hippocampus,neurogenesis in the dentate gyrus and neuronal numbers showed dynamic changes,which suggested that various pathological changes occur at different stages of depression.All experimental procedures and protocols were approved by the Experimental Animal Ethics Committee of Guangzhou University of Chinese Medicine of China in March 2015. 展开更多
关键词 chronic unpredictable MILD stress model continuous observation DEPRESSION depression-like behavior dynamic changes HIPPOCAMPUS miR-124 NEUROGENESIS dysfunction NEURONAL loss
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Surface seasonal mass changes and vertical crustal deformation in North China from GPS and GRACE measurements 被引量:8
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作者 Shuya Li Wenbin Shen +1 位作者 Yuanjin Pan Tengxu Zhang 《Geodesy and Geodynamics》 2020年第1期46-55,共10页
The Earth is an elastic body,and the surface mass loading changes will lead to elastic loading deformation on the surface of the Earth.In this study,we investigated the surface seasonal mass changes and vertical crust... The Earth is an elastic body,and the surface mass loading changes will lead to elastic loading deformation on the surface of the Earth.In this study,we investigated the surface seasonal mass changes and vertical crustal deformation in North China using the data obtained by the techniques of the Global Positioning System(GPS),Gravity Recovery and Climate Experiment(GRACE)and Surface Loading Models(SLMs).The seasonal annual signal and semi-annual signal obtained by the three techniques show strong correlations.The average value of the weighted root-mean-square(WRMS)of the all 30 sites is 58%after deducting the GRACE-obtained vertical deformation from the GPS-derived vertical deformation.However,the consistency of results between GPS and SLMs is not so good,with a 31%mean WRMS reduction,due to the fact that the global SLMs perform not well in North China.The GRACEmeasured long-term trend is deducted from the GPS-obtained vertical rates to reveal the crustal displacement caused by the underground factors such as tectonic movement and groundwater in North China.The results show that the rates of stations HECX and TJBH are very large,more than 10 mm/yr,which suggests that the surface subsidence is caused by excessive exploitation of groundwater. 展开更多
关键词 continuous GPS MEASUREMENT GRACE MEASUREMENT SURFACE Loading Models SEASONAL mass changes VERTICAL crustal displacement
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Comparison of channel geometry changes in Inner Mongolian reach of the Yellow River before and after joint operation of large upstream reservoirs 被引量:5
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作者 SU Teng WANG Suiji +1 位作者 MEI Yanguo SHAO Wenwei 《Journal of Geographical Sciences》 SCIE CSCD 2015年第8期930-942,共13页
The impact of reservoirs on downstream river channel change has been a scientific issue in fluvial geomorphology during the last few decades. However, it is still a difficult issue as to how to express quantitatively ... The impact of reservoirs on downstream river channel change has been a scientific issue in fluvial geomorphology during the last few decades. However, it is still a difficult issue as to how to express quantitatively the channel adjustment in the Inner Mongolian reach of the Yellow River induced by the joint operation of upstream reservoirs. Based on the shape parameters of channel cross-sections at four gauging stations in this river reach over a flooding season in two periods, 1978–1982 and 2008–2012, the present work investigated the channel changes in terms of shape parameter change rate under the same controlling water level in each flooding season at the channel cross-sections. Results showed that most of the change rates of the parameters evidently increased over a flooding season in both periods. However, the change rate of each parameter at the cross-sections decreased evidently in the latter period, compared with the former period. At the same time, the distribution pattern of the change rate of the shape parameters along the cross-sections thus changed from a convex curve in the former period to an S-shaped curve in the latter period. The obvious decrease of the change rates is related to the joint operation of the Liujiaxia and Longyangxia reservoirs. The reservoirs stored a large volume of water and decreased the peak discharge and maximum velocity in the flooding season; as a result, the erosion ability of the flood decreased accordingly. With the joint operation of the large reservoirs, the Inner Mongolian channel shrunk markedly. Therefore, the channel will present the possibility of an extreme flood in the future. Consequently, it is reasonable to adjust the function of the reservoirs in future. The total water and sediment discharges and the peak discharge in flooding seasons should be effectively controlled. Continuous shrinkage of the channel can thus be avoided and it can be ready for a potential extreme flood. 展开更多
关键词 channel cross-section shape parameters change rate RESERVOIR joint operation Yellow River
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Climatic Analysis of Continuous Rain in Southwest of Shandong 被引量:5
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作者 景安华 张宗灏 +1 位作者 孔凡忠 范文锋 《Meteorological and Environmental Research》 CAS 2010年第9期15-17,21,共4页
The continuous rain data from 1961 to 2007 in Heze city was analyzed in this paper.The results showed that continuous rain increased from north to south.Continuous rain processes took place most frequently in summer,n... The continuous rain data from 1961 to 2007 in Heze city was analyzed in this paper.The results showed that continuous rain increased from north to south.Continuous rain processes took place most frequently in summer,next in autumn,and the least in winter.Using wavelet to analyze the sequence of seasonal and annual continuous rain,it had a 5 years cycle oscillation at 2Y(year) level and a 20 years cycle oscillation at 10Y level.An abrupt climate change of continuous rain took place in 1986.Continuous rain was in a more period from 2001 to 2010 and would decrease gradually within the period. 展开更多
关键词 Southwest of Shandong continuous rain Wavelet analysis Abrupt climate change China
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Microstructure Evolution of AZ31 Mg Alloy during Change Channel Angular Extrusion
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作者 刘宇 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2011年第4期654-657,共4页
Microstructure evolution of AZ31 Mg alloy during change-channel angular extrusion (CCAE) was investigated. The grains of AZ31 Mg alloy were refined significantly from 500 mm to 15 mm after CCAE deformed at 523 K. Di... Microstructure evolution of AZ31 Mg alloy during change-channel angular extrusion (CCAE) was investigated. The grains of AZ31 Mg alloy were refined significantly from 500 mm to 15 mm after CCAE deformed at 523 K. Dislocations were induced at the initial stage of extrusion and they rearranged themselves to form dislocation boundaries and sub-grain boundaries during deformation. When the specimen through the horizontal change channel with the strain increased, the sub-boundaries evolved to high angle grain boundaries (HAGB). The process of grain refinement can be described as continuous dynamic recovery and recrystallization (CDRR). 展开更多
关键词 AZ31 Mg alloy grain refinement change channel angular extrusion (CCAE) continuous dynamic recovery and recrystallization (CDRR)
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Parametric Selection and Continual Combination of Building Surface
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作者 ZHANG Xu (Department of Archtectual, Wuhan University, Wuhan 430072,China) 《Wuhan University Journal of Natural Sciences》 CAS 2000年第1期75-79,共5页
A method to reparametrize G retional curve to obtain a C^1 curve is given. A practical G^1 continual connective between adjacent NURUS patches along common guadratic boundary curve is presented in this paper, and a s... A method to reparametrize G retional curve to obtain a C^1 curve is given. A practical G^1 continual connective between adjacent NURUS patches along common guadratic boundary curve is presented in this paper, and a specific algorithm for control points and weights of NURBS patches is discussed. 展开更多
关键词 PARAMETRIZATION cross-section design surface modeling non-uniform rational B-spline geometric continuity
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