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基于动态注意力机制和多模态循环融合的帕金森氏症识别 被引量:2
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作者 朱家英 徐志京 《计算机应用研究》 CSCD 北大核心 2023年第2期481-487,共7页
PD(Parkinson’s disease)的运动障碍会累及口、咽、腭肌以及面部肌肉,引起声带震颤和面部运动迟缓,为利用声纹和面部特征识别PD患者提供了可能。为了有效利用以上两种特征以提高PD识别率,提出了基于多尺度特征与动态注意力机制的多模... PD(Parkinson’s disease)的运动障碍会累及口、咽、腭肌以及面部肌肉,引起声带震颤和面部运动迟缓,为利用声纹和面部特征识别PD患者提供了可能。为了有效利用以上两种特征以提高PD识别率,提出了基于多尺度特征与动态注意力机制的多模态循环融合模型对患者进行识别检测。首先,设计了多尺度特征提取网络,将高、低层级特征的语义信息融合以得到完整的特征信息;其次,在多尺度特征融合过程中为了充分考虑模态间的相关性和互补性,提出了以不同模态信息互为辅助条件生成注意力特征图的动态注意力机制算法,降低特征融合时信息的冗余;最后设计了多模态循环融合模型,通过计算循环矩阵的每个行向量与特征向量间的哈达玛积得到更有效的融合特征,提高了模型性能。在自建数据集上进行的多组实验结果表明,提出的方法识别准确率高达96.24%,优于当前流行的单模态和多模态识别算法,可以有效区分PD患者和HP(healthy people),为高效识别PD患者奠定了基础。 展开更多
关键词 帕金森氏症 模态循环融合 多尺度特征 动态注意力机制
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积云参数化方案对热带降水年循环模态模拟的影响 被引量:11
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作者 张丽霞 周天军 +2 位作者 曾先锋 陈昊明 包庆 《大气科学》 CSCD 北大核心 2011年第4期777-790,共14页
本文利用中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室(LASG)发展的大气环流模式(SAMIL),采用Zhang-McFarlane(ZM)和Tiedtke(TDK)两种积云对流参数化方案,讨论了积云对流参数化方案对热带降水年循环模态模拟... 本文利用中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室(LASG)发展的大气环流模式(SAMIL),采用Zhang-McFarlane(ZM)和Tiedtke(TDK)两种积云对流参数化方案,讨论了积云对流参数化方案对热带降水年循环模态模拟的影响。结果表明,两种积云对流参数化方案均能合理再现热带降水年循环模态的基本分布特征。SAMIL两种对流方案中热带太平洋地区的春秋非对称模态偏差较大,印度季风以及北澳季风区季风模拟强度偏弱,西北太平洋季风以及非洲季风、美洲季风模态偏强。SAMIL两种参数化方案模拟的季风模态偏差主要来自于模式对北半球夏季西北太平洋降水的模拟。西北太平洋夏季,SAMIL两种参数化方案的对流层温度低层偏暖,高层偏冷,如此造成的对流不稳定是西北太平洋对流异常偏强,降水偏多的原因之一,同时模式中经向温度梯度模拟偏低,直接影响到东亚副热带西风急流偏弱,是急流出口区右侧的西北太平洋对流异常的动力条件。两种参数化方案的差异主要体现在ZM方案中的西北太平洋地区季风模态降水强于TDK方案,ZM方案低层比湿明显强于TDK方案与观测,是ZM方案夏季西北太平洋季风降水强于TDK方案与观测的重要因子之一。西北太平洋地区温度和湿度场的改进是SAMIL后续发展过程中需要重点解决的问题之一。 展开更多
关键词 积云对流参数化 全球季风 降水年循环模态
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BCC_CSM模式对热带降水年循环模态的模拟 被引量:11
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作者 张莉 吴统文 +4 位作者 辛晓歌 张洁 房永杰 王在志 魏敏 《大气科学》 CSCD 北大核心 2013年第5期994-1012,共19页
本文评估了国家气候中心发展的两个不同分辨率海—陆—气—冰多圈层耦合气候系统模式BCC_CSM1.1和BCC_CSM1.1(m)对热带降水两个年循环模态——揭示降水冬夏季节差异的季风模态和揭示过渡季节春季和秋季非对称特征的春秋非对称模态的模... 本文评估了国家气候中心发展的两个不同分辨率海—陆—气—冰多圈层耦合气候系统模式BCC_CSM1.1和BCC_CSM1.1(m)对热带降水两个年循环模态——揭示降水冬夏季节差异的季风模态和揭示过渡季节春季和秋季非对称特征的春秋非对称模态的模拟能力,讨论了模拟偏差产生的可能原因。分析结果表明,BCC_CSM1.1和BCC_CSM1.1(m)均能合理再现全球年平均降水的基本分布特征,也能较合理再现热带降水年循环模态的基本分布特征,尤其季风模态中降水与环流关于赤道反对称的特征;能够较合理再现春秋非对称模态与热带海洋表面温度(SST)年循环之间的关系。大气温度场、环流场以及热带SST的模拟偏差对降水季风模态有影响;热带SST年循环的偏差对降水春秋非对称模态的模拟偏差有贡献;模式分辨率对降水年循环模态的模拟也有一定影响。对比分析显示,大气模式和陆面模式水平分辨率提高之后模式在某些模拟性能上有所提高,这表现在:BCC_CSM1.1(m)模拟的1~12月降水气候态的空间变率更接近观测;热带海表温度年循环总体上更接近观测;模拟的热带降水年循环模态的部分特征更合理。但BCC_CSM1.1(m)的模拟结果相对观测仍存在较大偏差,有待进一步改进。 展开更多
关键词 降水年循环模态 气候系统模式 季风 分辨率
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高超声速并联TBCC总体性能分析与模态转换仿真 被引量:10
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作者 宋自航 唐海龙 陈敏 《航空发动机》 北大核心 2019年第1期33-39,共7页
为了解决涡轮冲压组合循环(TBCC)高超声速推进系统的推力间隙问题,通过在风扇前嵌入预冷器冷却进口空气的方法扩展涡轮基的工作上边界,采用变几何方案提高冲压发动机在低马赫数下的推力。建立了双模态TBCC稳态性能模型,计算对比了不同构... 为了解决涡轮冲压组合循环(TBCC)高超声速推进系统的推力间隙问题,通过在风扇前嵌入预冷器冷却进口空气的方法扩展涡轮基的工作上边界,采用变几何方案提高冲压发动机在低马赫数下的推力。建立了双模态TBCC稳态性能模型,计算对比了不同构型TBCC的推力性能,选定了涡轮-冲压模式转换区间,计算了转换过程的推力变化、燃油和液氮的消耗量。结果表明:采用预冷、变几何方案能填补不预冷、定几何方案的推力间隙,在模态转换过程所消耗的液氮占飞行器总质量的0.6%。 展开更多
关键词 模态涡轮冲压组合循环 推力间隙 预冷 变几何 模态转换 航空发动机
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基于全息希尔伯特频谱分析的交流串联电弧故障电流特征研究
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作者 吴自然 韩燕 陈冲 《电器与能效管理技术》 2024年第6期8-16,共9页
针对交流串联电弧故障信号特征提取和分析的难题,提出采用循环掩码经验模态分解(itEMD)进行信号分解以获取多层内涵模态分量(IMF),结合全息希尔伯特变换(HHT)展现高维幅度调制频率调制(AM-FM)谱图的分析方法,从而获取高区分度的电弧故... 针对交流串联电弧故障信号特征提取和分析的难题,提出采用循环掩码经验模态分解(itEMD)进行信号分解以获取多层内涵模态分量(IMF),结合全息希尔伯特变换(HHT)展现高维幅度调制频率调制(AM-FM)谱图的分析方法,从而获取高区分度的电弧故障信号特征谱图。采用基于GB/T 31143—2014的电弧故障实验平台,采集7种屏蔽负载模式下电弧故障电流信号,分析研究不同环境下电弧故障特征。所提方法对于电弧故障检测技术的开发具有一定的理论指导意义。 展开更多
关键词 交流电弧 串联电弧故障 全息希尔伯特频谱分析 循环掩码经验模态分解
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车辆行驶工况与特征的研究 被引量:38
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作者 张建伟 李孟良 +2 位作者 艾国和 张富兴 朱西产 《汽车工程》 EI CSCD 北大核心 2005年第2期220-224,245,共6页
先对几个典型国家和地区(美国、欧洲和日本)开发并采用的几种有代表性的行驶工况做了全面的介绍;接着,对它们各自的特征进行深入的研究和对比;最后得出几点结论。
关键词 车辆行驶工况 车辆保有量 模态循环 车速 稳态负荷测试 瞬态负荷测试 排放物
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Dynamics models of soil organic carbon 被引量:7
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作者 杨丽霞 潘剑君 《Journal of Forestry Research》 SCIE CAS CSCD 2003年第4期323-330,共8页
As the largest pool of terrestrial organic carbon, soils interact strongly with atmosphere composition, climate, and land change. Soil organic carbon dynamics in ecosystem plays a great role in global carbon cycle and... As the largest pool of terrestrial organic carbon, soils interact strongly with atmosphere composition, climate, and land change. Soil organic carbon dynamics in ecosystem plays a great role in global carbon cycle and global change. With development of mathematical models that simulate changes in soil organic carbon, there have been considerable advances in understanding soil organic carbon dynamics. This paper mainly reviewed the composition of soil organic matter and its influenced factors, and recommended some soil organic matter models worldwide. Based on the analyses of the developed results at home and abroad, it is suggested that future soil organic matter models should be developed toward based-process models, and not always empirical ones. The models are able to reveal their interaction between soil carbon systems, climate and land cover by technique and methods of GIS (Geographical Information System) and RS (Remote Sensing). These models should be developed at a global scale, in dynamically describing the spatial and temporal changes of soil organic matter cycle. Meanwhile, the further researches on models should be strengthen for providing theory basis and foundation in making policy of green house gas emission in China. 展开更多
关键词 Soil carbon Soil organic carbon Dynamic model
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逆变器并网系统谐振特性及预防措施 被引量:6
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作者 王喆 严欢 +2 位作者 邰克强 苏舟 钟帆 《电网与清洁能源》 CSCD 北大核心 2023年第7期99-107,共9页
作为新能源接入系统主要接口的逆变器,并网后不仅产生大量谐波电流,而且将改变系统阻抗特性,增大谐振的风险,为挖掘并网后的谐振特性并预防谐振事故的发生,首先结合阻抗法与传递函数法对逆变器并网系统建立阻抗模型;然后将循环模态分析... 作为新能源接入系统主要接口的逆变器,并网后不仅产生大量谐波电流,而且将改变系统阻抗特性,增大谐振的风险,为挖掘并网后的谐振特性并预防谐振事故的发生,首先结合阻抗法与传递函数法对逆变器并网系统建立阻抗模型;然后将循环模态分析运用于模型求解,探究并网逆变器中的控制参数及滤波参数对系统谐振分布的影响;将循环模态分析与改进粒子群算法结合,提出一种以系统预防谐振、降低逆变器成本为目标的优化设计法,将优化结果代入Matlab仿真模型,结果表明:优化后,不仅LCL滤波器的既有谐振点被消除,而且使系统输电线引起的谐振得到了有效抑制,证明了设计方法的有效性。 展开更多
关键词 并网逆变器 谐振特性 阻抗模型 循环模态分析 抑制谐振 优化设计法
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A Dynamic Modeling For Cyclic Total Reflux Batch Distillation 被引量:9
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作者 白鹏 宋爽 +1 位作者 盛敏 李晓峰 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2010年第4期554-561,共8页
Cyclic total reflux(CTR) batch distillation is a promising mode of the process but lacking of appropriate modeling for the period of filling the reflux drum.A new dynamic modeling method for the simulation of CTR batc... Cyclic total reflux(CTR) batch distillation is a promising mode of the process but lacking of appropriate modeling for the period of filling the reflux drum.A new dynamic modeling method for the simulation of CTR batch distillation is proposed in this work,in which the changes in column holdup and liquid flow rate during the filling of the drum,and the consequent change in valid number of theoretical plates are considered.The effect of drum holdup on operation time is investigated and the optimal drum holdup is obtained from the simulation.The dynamic modeling is compared to the conventional modeling without consideration of change in liquid flow rate. The experimental result shows that the present modeling is more reliable and more accurate,especially for the column with large liquid holdup. 展开更多
关键词 batch distillation cyclic total reflux dynamic modeling liquid holdup reflux drum
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Generation and Properties of Two-Mode Circular States 被引量:1
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作者 ZHANG Ke-Fu WANG Zhong-Jie 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第11期1101-1104,共4页
Two-mode circular states,which are superposition states from some two-mode coherent states,are studiedtheoretically.It is shown that under certain conditions two-mode circular states may exhibit nonclassical effects,s... Two-mode circular states,which are superposition states from some two-mode coherent states,are studiedtheoretically.It is shown that under certain conditions two-mode circular states may exhibit nonclassical effects,suchas sub-Poissonian statistics and intermode correlation.We propose schemes to generate two-mode circular states by theinteraction of a trapped ion with traveling wave lasers. 展开更多
关键词 two-mode circular states nonclassical properties trapped ion
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Three-Mode Cyclic Squeezed States Constructed via EPR Entangled State
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作者 XU Xue-Fen 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第5期905-908,共4页
We construct the three-mode cyclic squeezed states and analyze its squeezing property by using the technique of integration within an ordered product of operators and the natural representation of the two-mode squeezi... We construct the three-mode cyclic squeezed states and analyze its squeezing property by using the technique of integration within an ordered product of operators and the natural representation of the two-mode squeezing operator in the Einstein-Podolsky-Rosen entangled state basis. 展开更多
关键词 three-mode cyclic squeezed state EPR entangled state
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Eco-budget-A Model of Urban Environmental Management
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作者 Hao Weixia Teng Li Wang Ziyan 《Ecological Economy》 2005年第4期13-17,共5页
In this paper, a new model of urban environmental resource management is introduced. The article analyzes the gap between urban environmental management and the management of economy and human resources. The significa... In this paper, a new model of urban environmental resource management is introduced. The article analyzes the gap between urban environmental management and the management of economy and human resources. The significance, the key points, the implementation procedures, and steps of eco-budget cycle are discussed. 展开更多
关键词 environmental management ECO-BUDGET
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FEM Modal Analysis on the Gravity Support System of ITER
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作者 JIAN Guangde MOU Zongze LONG Yongxing ZHOU Caipin WANG Aike HOU Binglin ZOU Hui 《Southwestern Institute of Physics Annual Report》 2006年第1期188-189,共2页
The three-dimensional finite element method model with 20 degree sector of the ITER overall gravity support system was built by the ANSYS software. The modal analysis of the gravity support system was made and first t... The three-dimensional finite element method model with 20 degree sector of the ITER overall gravity support system was built by the ANSYS software. The modal analysis of the gravity support system was made and first ten natural frequencies and vibration modes of the gravity support system were calculated by using Block Lanczos method. The results of modal analysis on ITER represent that the stiffness of flexible plates has influenced greatly for the natural frequency of the system. 展开更多
关键词 Modal analysis Cyclic symmetry FEM
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Research on Development Mode of Industrial Circular Economy of Country
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作者 LI Pei-zhe 《International English Education Research》 2014年第3期123-125,共3页
In recent years, the Industrial economy of country although maintained a high growth rate, but most industry which is still extensive economic growth mode. This paper taking Dong'e County as an example, discusses the... In recent years, the Industrial economy of country although maintained a high growth rate, but most industry which is still extensive economic growth mode. This paper taking Dong'e County as an example, discusses the idea of circular economy in industrial applications, in the analysis of Situation and the existence questions of Dong'e County Industrial Development Present, pushing forward circular eco-industrial development inevitability, Preliminary design of Dong'e County recycling ecological industry development mode. 展开更多
关键词 COUNTRY circular economy ecological industry idevelopment mode.
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Contrastive Study of the Circular Economy of Coal Resource City Based on Ecological Efficiency and C Model
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作者 于会录 董锁成 +2 位作者 李宇 李泽红 李飞 《Journal of Resources and Ecology》 CSCD 2016年第5期323-333,共11页
Being a developing country, the evaluation of Chinese circular economy should have its particular crite- rion that suits for specific national conditions. With the growth of economy, Chinese environmental loads should... Being a developing country, the evaluation of Chinese circular economy should have its particular crite- rion that suits for specific national conditions. With the growth of economy, Chinese environmental loads should be permitted to increase at an appropriate speed. Based on this concept, this paper divides the process of evaluation into two parts which include evaluation of development level and evaluation of development performance. Firstly, this paper sets up a reference system which includes Zaozhuang City of Shandong Province, Jiaozuo City of Henan province, Shizuishan City of Ningxia Hui Autonomous Region and China that is regarded as a region respectively, analyzes the development level of circular economy of coal resource cities based on the evaluation indicator of ecological efficiency, and puts forward the future direction of circular economy of coal resource cities. Secondly, based on C Model of Circular Economy, this paper constructs the measurement model of development perform- ance in which study regions are analyzed in a particular period that is from 2000 to 2020, and evaluates the de- velopment performance of circular economy for study regions according to the relationship of growth multiples between economic scale and environmental loads. We can draw several main conclusions: firstly, the development pathways of all four study regions belong to type I[ which resource efficiency is preferred. Secondly, the com- prehensive energy consumption efficiencies of coal resource cities were left far behind by China's average level. Thirdly, the circular economies of all study regions have achieved remarkable progress. Fourthly, the development level of circular economy can be evaluated from two dimensions which consist of horizontal comparison method and vertical comparison method. Fifthly, C model is an appropriate development model that suits for Chinese na- tional conditions and could be selected as an important method to evaluate regional development performance of circular economy. 展开更多
关键词 ecological efficiency C Model circular economy identification index EVALUATION coal resource city
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Terrestrial Ecosystem Modeling with IBIS:Progress and Future Vision 被引量:1
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作者 LIU Jinxun LU Xuehe +5 位作者 ZHU Qiuan YUAN Wenping YUAN Quanzhi ZHANG Zhen GUO Qingxi DEERING Carol 《Journal of Resources and Ecology》 CSCD 2022年第1期2-16,共15页
Dynamic Global Vegetation Models(DGVM)are powerful tools for studying complicated ecosystem processes and global changes.This review article synthesizes the developments and applications of the Integrated Biosphere Si... Dynamic Global Vegetation Models(DGVM)are powerful tools for studying complicated ecosystem processes and global changes.This review article synthesizes the developments and applications of the Integrated Biosphere Simulator(IBIS),a DGVM,over the past two decades.IBIS has been used to evaluate carbon,nitrogen,and water cycling in terrestrial ecosystems,vegetation changes,land-atmosphere interactions,land-aquatic system integration,and climate change impacts.Here we summarize model development work since IBIS v2.5,covering hydrology(evapotranspiration,groundwater,lateral routing),vegetation dynamics(plant functional type,land cover change),plant physiology(phenology,photosynthesis,carbon allocation,growth),biogeochemistry(soil carbon and nitrogen processes,greenhouse gas emissions),impacts of natural disturbances(drought,insect damage,fire)and human induced land use changes,and computational improvements.We also summarize IBIS model applications around the world in evaluating ecosystem productivity,carbon and water budgets,water use efficiency,natural disturbance effects,and impacts of climate change and land use change on the carbon cycle.Based on this review,visions of future cross-scale,cross-landscape and cross-system model development and applications are discussed. 展开更多
关键词 IBIS ecological model PRODUCTIVITY carbon cycle global change
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Quantization of black hole entropy from unstable circular null geodesics
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作者 Shao-Wen Wei Yu-Xiao Liu Chun-E Fu 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2016年第4期29-36,共8页
The quasinormal mode frequencies can be understood from the massless particles trapped at the unstable circular null geodesics and slowly leaking out to infinity. Based on this viewpoint, in this paper, we semiclassic... The quasinormal mode frequencies can be understood from the massless particles trapped at the unstable circular null geodesics and slowly leaking out to infinity. Based on this viewpoint, in this paper, we semiclassically construct the entropy spectrum of the static and stationary black holes from the null geodesics. The result shows that the spacing of the entropy spectrum only depends on the property of the black hole in the eikonal limit. Moreover, for a black hole far from the extremal case, the spacing is found to be smaller than 2π for any dimension, which is very different from the result of the previous work by using the usual quasinormal mode frequencies. 展开更多
关键词 black hole entropy spectrum null geodesics quantization
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Study on integrated calculation of ecological water demand for basin system 被引量:4
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作者 JIN Xin YAN DengHua +4 位作者 WANG Hao ZHANG Cheng TANG Yun YANG GuiYu WANG LingHe 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第10期2638-2648,共11页
The operation of reservoir(s) has a certain impact on the downstream hydrologic regime,and even endangers the ecological water safety of river corridor and ecosystems which interact with river system.Therefore,ecologi... The operation of reservoir(s) has a certain impact on the downstream hydrologic regime,and even endangers the ecological water safety of river corridor and ecosystems which interact with river system.Therefore,ecological operation needs to be carried out in order to ensure ecological water use of downstream zone.The key technological support is the estimation and integrated calculation of ecological water demand.The connotation of the integrated calculation on ecological water demand lies on that the ecological water demand of different ecosystems is integrated to meet the requirements of water allocation and operation on watershed scale in terms of hydrological cycle.Considering the practical requirement of ecological operation of reservoir(s),this study proposed an integrated calculation approach of ecological water demand according to the ecological water demand in various ecosystems as well as the hydraulic connection among them;it established an integrated calculation model of regional ecological water demand by means of the distributed hydrological model,and studied the integrated calculation in Yalong River basin which is the source area of the west route of South-North Water Transfer Project as an example.The results indicated that the integrated calculation model more effectively combined the ecological water demand and hydraulic connection of ecosystems in time and space,compared with the lumped water balance analysis,since the former conquered the defect of insufficient ecological water source and supplement on multiple spatial and temporal scales,and met the demand of ecological operation of reservoir(s). 展开更多
关键词 ecological operation of reservoir ecological water demand integrated calculation distributed hydrological model west route of South-North Water Transfer Project in Yalong River source area
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