多变量温度系统的变结构控制     

李国胜  张文武  王海燕 《中国海洋大学学报(自然科学版)》1997,(4)

研究变结构解耦控制及其在多变量系统中的应用。变结构系统的滑动模态对参数的摄动和外来干扰是自适应的；各耦合回路可被认为是在一定条件下的外部干扰。对一个三路耦合温度控制系统的仿真实验给出了令人满意的结果。  相似文献   

混凝土结构的切割爆破技术          下载免费PDF全文

龚汉松 《探矿工程》2007,34(11):54-56

通过大量的素混凝土及钢筋混凝土结构切割爆破实践,分析归纳出其主要爆破参数计算方法和工程施工技术特点。将这些计算方法和技术要点应用于工程实践,取得了较好的切割爆破效果,达到了相应的工程目的。  相似文献   

Heterogeneous tectonic inversion of the Mid-Polish Trough related to crustal architecture, sedimentary patterns and structural inheritance     

J. Lamarche  M. Scheck  B. Lewerenz 《Tectonophysics》2003,373(1-4):75

Using a 3-D structural model, we performed a basin-scale analysis of the tectonically inverted Mid-Polish Swell, which developed above the NW–SE-oriented Teisseyre-Tornquist Zone. The later separates the Paleozoic West European Platform from the Precambrian East European Craton. The model permits a comparison between the present depths and sedimentary thicknesses of five layers within the Permian–Mesozoic and Cenozoic successions. The inversion of the NW–SE-trending Mid-Polish Trough during the Late Cretaceous–Paleogene resulted in uplift of a central horst, the Mid-Polish Swell, bounded by two lateral troughs. These structural features are induced by squeezing of a weak crust along the Teisseyre-Tornquist Zone. The swell is characterized by an inherited segmentation which is due to NE–SW transversal faults having crustal roots. From NW to SE, we distinguish the Pomeranian, Kujavian, and Ma opolska segments, that are separated by two transversal faults. During the inversion, the Zechstein salt occurring in the Pomeranian and Kujavian segments in the NW acted as decoupling level between the basement and the post-salt cover, leading to disharmonic deformation. Conversely, because no salt occurs in the SE, both basement and cover were jointly deformed. The vertical tectonic uplift at the surface is estimated to amount to 3 km in the Ma opolska segment. The structural inheritance of the basement is expressed by the heterogeneous geometry of the swell and tectonic instability during Mesozoic sedimentation. The reasons for the inheritance are seen in the mosaic-type Paleozoic basement SW of the Teisseyre-Tornquist Zone, contrasting the Precambrian East European Craton which acted as a stable buttress in the NE. The horst and trough geometry of Cenozoic sediments blanketing the Mid-Polish swell reveals the ongoing intracontinental compressional stress in Poland.  相似文献   

中国东部燕山期和四川期岩石圈构造滑脱与岩浆起源深度   总被引：9，自引：0，他引：9  

万天丰  王亚妹  刘俊来 《地学前缘》2008,15(3):1-35

较确切地研究岩石圈内部构造滑脱面在地质历史时期形成的时间和部位是当前大地构造学研究的一个重要课题。通过大量收集中国东部燕山期(205~135Ma)和四川期(135~52Ma)岩浆起源深度资料来判断岩石圈内部和底部是否存在局部的构造滑脱界面,是否发生层圈相互作用,是否发生部分的解耦现象,是一种可行的研究方法。研究表明,中国东部燕山期和四川期岩石圈板块的构造滑脱、圈层的解耦作用及相互作用主要集中在中地壳、莫霍面与区域性主干断层的交线附近,而岩石圈板块的底面却并不存在大幅度的滑移。中国东部燕山期和四川期岩浆活动比较发育的地区基本上都位于大兴安岭—山西西部—武陵山—十万大山一线以东地区,而在此线以西地区岩浆活动相当微弱。笔者认为,在侏罗—白垩纪时期,该线以西缺少岩浆活动的地区可能就是当时的大陆型岩石圈,而该线以东岩浆活动剧烈的地区可能就属于海陆过渡型岩石圈。中国东部岩石圈的转型和"变薄",不太可能是深部地幔羽、去根作用、深部地幔热物质上涌或大陆伸展作用的结果,也不太可能与太平洋板块的俯冲作用有直接联系。  相似文献   

中国能源碳足迹时空格局演化及脱钩效应   总被引：12，自引：5，他引：7  

潘竟虎  张永年 《地理学报》2021,76(1):206-222

利用DMSP-OLS夜间灯光数据和碳排放统计数据,构建碳排放面板数据模型,模拟了2000—2013年中国的碳排放量。运用探索性时空数据分析（ESTDA）框架体系,从时空交互视角分析2001—2013年碳足迹的空间格局和时空依赖动态演化;利用改进的Tapio脱钩模型对3个时间段336个地级单元环境碳负荷与经济增长之间的脱钩效应进行综合分析。研究表明：① 2000—2013年,中国的碳排放在时空演变上既表现出稳中有进的总体特征,也存在快速增长的阶段特征。② 碳足迹和碳赤字均呈逐年增长趋势,年均增长率分别为4.82%和5.72%;碳足迹和碳赤字整体北方大于南方,不同的行政单元尺度下碳足迹和碳赤字空间异质性特征明显。各地级单元碳足迹变异系数逐步增大,存在极为显著的空间自相关特征。③ LISA时间路径相对长度北方大于南方,且呈由沿海地区向中西部地区递增的趋势;LISA时间路径弯曲度整体上则由沿海地区向内陆地区递减。④ 综合脱钩指数整体以弱脱钩型为主,但弱脱钩型城市数量持续减少,扩张连接、扩张负脱钩区域数量逐渐增多且向中西部及东北地区聚集分布;全国平均脱钩弹性值逐步增长,变异系数持续下降。  相似文献   

Spatial-temporal characteristics and decoupling effects of China’s carbon footprint based on multi-source data   总被引：1，自引：1，他引：0  

Zhang  Yongnian  Pan  Jinghu  Zhang  Yongjiao  Xu  Jing 《地理学报(英文版)》2021,31(3):327-349

In 2007, China surpassed the USA to become the largest carbon emitter in the world. China has promised a 60%–65% reduction in carbon emissions per unit GDP by 2030, compared to the baseline of 2005. Therefore, it is important to obtain accurate dynamic information on the spatial and temporal patterns of carbon emissions and carbon footprints to support formulating effective national carbon emission reduction policies. This study attempts to build a carbon emission panel data model that simulates carbon emissions in China from 2000–2013 using nighttime lighting data and carbon emission statistics data. By applying the Exploratory Spatial-Temporal Data Analysis(ESTDA) framework, this study conducted an analysis on the spatial patterns and dynamic spatial-temporal interactions of carbon footprints from 2001–2013. The improved Tapio decoupling model was adopted to investigate the levels of coupling or decoupling between the carbon emission load and economic growth in 336 prefecture-level units. The results show that, firstly, high accuracy was achieved by the model in simulating carbon emissions. Secondly, the total carbon footprints and carbon deficits across China increased with average annual growth rates of 4.82% and 5.72%, respectively. The overall carbon footprints and carbon deficits were larger in the North than that in the South. There were extremely significant spatial autocorrelation features in the carbon footprints of prefecture-level units. Thirdly, the relative lengths of the Local Indicators of Spatial Association(LISA) time paths were longer in the North than that in the South, and they increased from the coastal to the central and western regions. Lastly, the overall decoupling index was mainly a weak decoupling type, but the number of cities with this weak decoupling continued to decrease. The unsustainable development trend of China's economic growth and carbon emission load will continue for some time.  相似文献   

青藏高原城镇化与生态环境交互影响关系分析   总被引：3，自引：2，他引：3  

冯雨雪  李广东 《地理学报》2020,75(7):1386-1405

科学评估青藏高原城镇化与生态环境交互影响的总体状况,对优化城镇化速度和质量,修复和提升生态环境状态具有重要意义。在梳理青藏高原城镇化与生态环境交互影响研究进展基础上,本文尝试构建一套完整的城镇化与生态环境交互影响分析模型体系,实现从综合评价指数分析、耦合协调度量化、耦合类型识别、解耦路径探索到未来趋势预测的全过程解析。以青藏高原及其省域、地级单元多尺度分析对比为手段,尝试厘清尺度之间的差异性,识别出问题区域,并提出针对性的改进措施。研究发现,青藏高原不同尺度间城镇化综合评价指数呈阶段性上升趋势,青海的整体城镇化指数高于西藏;生态环境指数变化趋势不同,青海呈下降态势,西藏则趋向平稳,各地级单元生态环境指数存在分层现象。青藏高原不同尺度城镇化与生态环境耦合协调度总体呈上升趋势,协调类型由失调衰退类向濒临失调衰退类转变,最后转为勉强协调发展类,基本属于城镇化滞后型。城镇化指数与生态环境指数呈现出强脱钩、弱脱钩交互出现的波动态势,说明不同尺度间存在城镇化与生态环境的负相互作用,消极城镇化现象突出。通过预测,青藏高原各地级单元在未来10年内,系统耦合协调度将稳步上升,但各地增长速度将存在显著差距。  相似文献   

Time-domain analysis of wave propagation in 3-D unbounded domains by the scaled boundary finite element method     

《Soil Dynamics and Earthquake Engineering》2015

Transient wave propagation in three-dimensional unbounded domains is studied. An efficient numerical approach is proposed, which is based on using the displacement unit-impulse response matrix representing the interaction force–displacement relationship on the near field/far field interface. Spatially, an approximation is used to reduce the computational effort associated with the large size of three-dimensional problems. It is based on subdividing the fully coupled unbounded domain into multiple subdomains. The displacement unit-impulse response matrices of all subdomains are calculated separately. The error associated with this spatial decoupling can be reduced by placing the near field/far field interface further away from the domain of interest. Detailed parameter studies have been conducted using numerical examples, in order to provide guidelines for the proposed spatially local schemes, and to demonstrate the accuracy and high efficiency of the proposed method for three-dimensional soil–structure interaction problems.  相似文献   

去耦合方法求解非均质地区地下水中多组分反应-运移模型     

霍吉祥  宋汉周 《岩土力学》2015,36(Z2):57-63

近些年来地下水中多组分反应-运移模型在地球科学及环境领域开始得到应用,但其求解较为复杂,为了提高计算效率,可以采用去耦合化方法处理,从而使模型求解得到简化。针对自然界中广泛存在的非均质地质体,提出该类条件下的去耦合化方法,即根据水-岩间、水溶组分间反应的不同,将整个研究区划分为若干子区域,获得对应的去耦合化矩阵。对化学场中各子区域间相邻边界进行设定,达到简化模型求解的目的。最后,以一维非均质介质中基于热力学平衡的反应-运移问题作为算例,基于以上方法进行求解,并与该算例经PHAST软件所示的结果较为一致。结果表明,基于去耦合化方法获得的各离子浓度随时间演变和沿空间分布特征与PHAST所示的结果较为一致,显示该方法在非均质区域模拟溶质运移等方面具有较好的适用性。  相似文献   

工程爆破中径向水不耦合系数效应数值仿真   总被引：7，自引：0，他引：7  

王志亮  李永池 《岩土力学》2005,26(12):1926-1930

在实际工程爆破中,水不耦合炮孔是较常见的,其中水不耦合装药系数是影响爆破效果的关键因素之一。该系数取不同的值,将产生不同的应力波传播机理以及介质的损伤破坏程度。以往的研究主要集中于理论解析法和模型试验法。基于大型非线性动力分析软件LS-DYNA,采用著名的混凝土损伤Johnson-Holmquist-Concrete模型,针对无限混凝土介质水不耦合装药爆破中不同径向耦合系数Kd,展开了对比数值计算,综合分析了损伤破坏区分布和孔壁压力、加速度以及速度等与径向不耦合系数间的关系,得出的结论具有一定的参考价值。  相似文献