检索结果-南通市图书馆

Runoff projections of the Qinling Mountains and their impact on water demand of Guanzhong region in Northwest China

Journal of Mountain Science 2022年第8期19卷 2272-2285页

作者： ZHANG Zhao-peng DUAN Ke-qin liU Huan-cai MENG Ya-li CHEN Rong li Da-wei li shuang-shuang School of Geographical Sciences and Tourism Shaanxi Normal UniversityXi'an 710062China School of Geographical Sciences Shanxi Normal UniversityLinfen 041081China

The Qinling Mountains are the main source of water supply to the Weihe River and Hanjiang River,but systematic studies on runoff changes in this region are *** study simulated the annual runoff in the Qinling Mountains from 1970 to 2015 using the Variable Infiltration Capacity(VIC)hydrological model and projected runoff changes from 2015 to 2100 under different Shared Socio-economic Pathways(SSPs).Moreover,the water demand in the north and south of the Qinling Mountains from 2019 to 2100 was analyzed by constructing a system dynamic *** results show that the mean annual runoff in the southern and northern slopes of the Qinling Mountains from 1970 to 2015 were 21.5×10^(9) and 3.52×10^(9) m^(3),*** the SSP1-2.6,SSP2-4.5,SSP3-7.0,and SSP5-8.5 scenarios from 2015 to 2100,the mean annual runoff in the southern(northern)slope will increase by 2.9(1.5),2.0(1.4),2.7(1.6),and-2.1(0.4)×10^(9) m^(3),*** mean annual water consumption in the northern foothills of the Qinling Mountains for Baoji,Xi’an,and Weinan cities is projected to increase from 4.1×10^(9) m^(3) in 2015 to 7.6×10^(9) m^(3) in 2100,while that in the southern foothills for Hanzhong,Ankang,and Shangluo cites is projected to increase from 2.7×10^(9) m^(3) in 2015 to 4.8×10^(9) m^(3) in ***,runoff in the southern slope is much larger than the water demand in the southern *** increase of runoff in the northern slope cannot satisfy the water demand in the northern ***,the South-to-North Water Transfer project is proposed for meeting the water demand in the northern *** the premise of ensuring downstream water demand,approximately 10.5×10^(9) m^(3) of water resources can be transferred from the southern slope to the Weihe River and the Beijing-Tianjin-Hebei-Henan regions under SSP1-2.6,but only 3.9×10^(9) m^(3) can be transferred under SSP5-8.5.

关键词： Qinling Mountains Climate change Runoff Hydrological model CMIP6 System Dynamics

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

Spatial skyline query method based on Hilbert R-tree in multi-dimensional space

引用

High Technology Letters 2019年第3期25卷 262-270页

作者： li Song Zhang liping li shuang Hao Xiaohong College of Computer Science and Technology Harbin University of Science and Technology

In view of the shortage of the spatial skyline query methods(SSQ methods) in dealing with the problem of skyline query in multidimensional space, a spatial skyline query method based on Hilbert R-tree in multidimensional space is proposed. This method takes the advantages of Hilbert R-tree which combines R-tree and Hilbert curve with high efficiency and dimensionality reduction. According to the number of query points, the proposed method in static query point environment is divided into single query point of SSQ method(SQ-HSKY algorithm) and multi-query points of SSQ method(MQP-HSKY algorithm). The SQ-HSKY method uses the spatial relationship between objects to propose pruning strategy and the skyline set in the filtering and refining process are computed. The MQP-HSKY method uses the topological relationship between data points and query points to prune non skyline points and generate the dominant decision circle to obtain the global skyline set. Theoretical study and experiments confirm the effectiveness and superiority of these methods on the skyline query.

关键词： skyline query Hilbert curve R-tree Hilbert R-tree topological relationship

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

Structural reliability analysis using a hybrid HDMR-ANN method

引用

Journal of Central South University 2017年第11期24卷 2532-2541页

作者： Bhaw Nath Jha li Hong-shuang Key Laboratory of Fundamental Science for National Defense-Advanced Design Technology of Flight Vehicles Nanjing University of Aeronautics and AstronauticsNanjing 210016China

A new hybrid method is proposed to estimate the failure probability of a structure subject to random parameters. The high dimensional model representation(HDMR) combined with artificial neural network(ANN) is used to approximate implicit limit state functions in structural reliability analysis. HDMR facilitates the lower dimensional approximation of the original limit states function. For evaluating the failure probability, a first-order HDMR approximation is constructed by deploying sampling points along each random variable axis and hence obtaining the structural responses. To reduce the computational effort of the evaluation of limit state function, an ANN surrogate is trained based on the sampling points from HDMR. The component of the approximated function in HDMR can be regarded as the input of the ANN and the response of limit state function can be regarded as the target for training an ANN surrogate. This trained ANN surrogate is used to obtain structural outputs instead of directly calling the numerical model of a structure. After generating the ANN surrogate, Monte Carlo simulation(MCS) is performed to obtain the failure probability, based on the trained ANN surrogate. Three numerical examples are used to illustrate the accuracy and efficiency of the proposed method.

关键词： high dimensional model representation structural reliability artificial neural network failure probability

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

Utilization of electroless plating to prepare Cu-coated cotton cloth electrode for flexible li-ion batteries

引用

Rare Metals 2021年第2期40卷 400-408页

作者： Mai Shi Shun Wu Zhen-Dong Han shuang li Yu-Ting Pan shuang Yuan Qiang Wang School of Metallurgy Northeastern UniversityShenyang110819China The State Key Lab of Rolling and Automation and Key Laboratory of Ecological Metallurgy of Multimetallic Mineral(Ministry of Education)Northeastern UniversityShenyang110819China Key Laboratory of Electromagnetic Processing of Materials(Ministry of Education) Northeastern UniversityShenyang110819China Foreign Studies College of Northeastern University Shenyang110819China

Flexible,lightweight and high conductivity substrates are required for the development of next-generation flexible li-ion batteries(liBs).In addition,the interfacial strength between the active material and flexible substrate should be optimized for high-performance ***,cotton cloth(CC)is employed as a flexible substrate,and electroless plating is utilized to deposit a layer of Cu nanoparticles,which enhances the conductivity of CC and acts as a precursor for the active material,i.e.,*** results reveal that the in situ etching and subsequent heat treatment converted Cu film into CuO nanowires on CC ***,carbon nano tubes(CNTs)are introduced to enhance the connectivity of CuO nano ***,the CuO/CNT/CC electrode rendered a high areal capacity of>700μAh-cm^(-2)after100 charge/discharge cycles as well as excellent rate *** current work presents a novel route to develop desirable substrates for next-generation flexible li-ion batteries.

关键词： Electroless plating Cotton cloth In situ etching CuO nanowires array Flexible electrode

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

Prediction of constrained modulus for granular soil using 3D discrete element method and convolutional neural networks

引用

Journal of Rock Mechanics and Geotechnical Engineering 2024年第11期16卷 4769-4781页

作者： Tongwei Zhang shuang li Huanzhi Yang Fanyu Zhang Key Laboratory of Mechanics on Disaster and Environment in Western China MOECollege of Civil Engineering and MechanicsLanzhou UniversityLanzhou730000China

To efficiently predict the mechanical parameters of granular soil based on its random micro-structure,this study proposed a novel approach combining numerical simulation and machine learning ***,3500 simulations of one-dimensional compression tests on coarse-grained sand using the three-dimensional(3D)discrete element method(DEM)were conducted to construct a *** this process,the positions of the particles were randomly altered,and the particle assemblages ***,besides confirming the influence of particle size distribution parameters,the stress-strain curves differed despite an identical gradation size statistic when the particle position ***,the obtained data were partitioned into training,validation,and testing datasets at a 7:2:1 *** convert the DEM model into a multi-dimensional matrix that computers can recognize,the 3D DEM models were first sliced to extract multi-layer two-dimensional(2D)cross-sectional *** information was then eliminated via gray processing,and the data were stacked to form a new 3D matrix representing the granular soil’s ***,utilizing the Python language and Pytorch framework,a 3D convolutional neural networks(CNNs)model was developed to establish the relationship between the constrained modulus obtained from DEM simulations and the soil’s *** mean squared error(MSE)function was utilized to assess the loss value during the training *** the learning rate(LR)fell within the range of 10-5e10-1,and the batch sizes(BSs)were 4,8,16,32,and 64,the loss value stabilized after 100 training epochs in the training and validation *** BS?32 and LR?10-3,the loss reached a *** the testing set,a comparative evaluation of the predicted constrained modulus from the 3D CNNs versus the simulated modulus obtained via DEM reveals a minimum mean absolute percentage error(MAPE)of 4.43%under the optimized condition,demonstrating the accuracy of thi

关键词： Soil structure Constrained modulus Discrete element model(DEM) Convolutional neural networks(CNNs) Evaluation of error

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

KGM Derived CNTs foam/Epoxy Composites with Excellent Microwave Absorbing Performance

引用

Journal of Wuhan University of Technology(Materials Science) 2022年第2期37卷 155-162页

作者： ZHANG Xiaoyan ZHAO Yan li shuang WANG Kai School of Materials and Engineering Beihang UniversityBeijing 100191China Beijing Institute of Aeronautical Materials Beijing 100095China

We adopted a green,economical and simple method in which konjac glucomannan (KGM) was used as a carrier to support CNTs to construct a three-dimensional structure filled with epoxy resin to improve the absorbing performance of epoxy *** the reflection of the internal multi-level pore structure and the dielectric loss effect of CNTs,the dissipation and absorption of electromagnetic waves are *** KGM derived CNTs foam exhibits high specific microwave absorption performance with a minimum absorption of-25.2 dB at 11.3 GHz and a qualified bandwidth of around 2.89 GHz (RL≤-10 dB),which is achieved by KDCF5/Epoxy with the coating layer thickness of 1.8 *** provide a novel and cost-effective method to achieve excellent absorbing performance under thin thickness and low *** CNTs foam also has a lower density (6.5 mg/cm^(3)) and can improve the absorbing properties of the epoxy while maintaining its various advantages,thereby expanding the application range of the epoxy resin.

关键词： Microwave absorption performance CNTs KGM Carbon foam

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

A Sample-Efficient Actor-Critic Algorithm for Recommendation Diversification

引用

Chinese Journal of Electronics 2020年第1期29卷 89-96页

作者： li shuang YAN Yanghui REN Ju ZHOU Yuezhi ZHANG Yaoxue Department of Computer Science and Technology Tsinghua University

Diversifying recommendation results gains benefits from satisfying user’s existing interests as well as exploring novel information needs. Recently proposed Monte-Carlo based reinforcement learning method suffers from sample inefficiency, large variance, and even failing to perform well in large action space. We propose a novel actor-critic reinforcement learning algorithm for recommendation diversification in order to solve the above mentioned problems. The actor acts as the ranking policy, while the introduced critic predicts the expected future rewards of each candidate action. The critic target is updated by full Bellman equation and the actor network is optimized using expected gradient in the whole action space. To further stabilize and improve the performance, we also add policy-filtered critic supervision loss. Experiments on MovieLens dataset well demonstrate the effectiveness of our approach over multiple competitive methods.

关键词： Recommender system Diversity Reinforcement learning Actor-critic

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Comparative Analysis on Public and Private Partnership Legislation

引用

学术界 2019年第6期 204-213页

作者： Fu Jingjing li shuang School of Law Southwest Petroleum University

Public-Private Partnerships (PPPs) mode is a new governance mode which combines the advantages of government,private investor and the financial institution ***,there is no sound legal system for PPPs in China at ***,it is critical to build a PPP legal legislation in order to facilitate investments in complex and long-term PPP arrangements,reduce transaction costs,ensure appropriate regulatory controls,and provide legal and economic mechanisms to enable the resolution of contract *** article provides an international perspective on PPP legal framework by drawing upon the existing of PPP laws from several countries.

关键词： PPPs legislation comparative analysis

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

Extracting Eco-hydrological Information of Inland Wetland from L-band Synthetic Aperture Radar Image in Honghe National Nature Reserve, Northeast China

引用

Chinese Geographical Science 2011年第2期21卷 241-248页

作者： SUN Yonghua GONG Huili li Xiaojuan PU Ruiliang li shuang College of Resources Environment & Tourism Capital Normal University Beijing 100048 China National Key Laboratory Cultivation Base of Urban Environmental Processes & Digital Analog Beijing 100048 China 3. Department of Geography University of South Florida Tampa FL 33620 USA

Taking a typical inland wetland of Honghe National Nature Reserve (HNNR), Northeast China, as the study area, this paper studied the application of L-band Synthetic Aperture Radar (SAR) image in extracting eco-hydrological information of inland wetland. Landsat-5 TM and ALOS PALSAR HH backscatter images were first fused by using the wavelet-IHS method. Based on the fused image data, the classification method of support vector machines was used to map the wetland in the study area. The overall mapping accuracy is 77.5%. Then, the wet and dry aboveground biomass estimation models, including statistical models and a Rice Cloudy model, were established. Optimal parameters for the Rice Cloudy model were calculated in MATLAB by using the least squares method. Based on the validation results, it was found that the Rice Cloudy model produced higher accuracy for both wet and dry aboveground biomass estimation compared to the statistical models. Finally, subcanopy water boundary information was extracted from the HH backscatter image by threshold method. Compared to the actual water borderline result, the extracted result from L-band SAR image is reliable. In this paper, the HH-HV phase difference was proved to be valueless for extracting subcanopy water boundary information.

关键词： inland wetland ALOS PALSAR wetland mapping aboveground biomass estimation subcanopy water boundary extraction

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

Synthesis,crystal structure,and magnetic properties of a new onedimensional chain antiferromagnet Co(ox)(bib)·H_(2)O(ox=oxalate;bib=1,4-bis(imidazole-1-yl)benzene)

引用

Nano Research 2023年第2期16卷 3552-3557页

作者： Yan She Yanhong Wang shuang li Tao Wang Hongcheng Lu School of Chemistry and Chemical Engineering Key Laboratory of Material Chemistry for Energy Conversion and StorageHubei Key Laboratory of Bioinorganic Chemistry&Materia MedicaHuazhong University of Science and TechnologyWuhan 430074China Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China

A new one-dimensional(1D)chain antiferromagnet Co(ox)(bib)·H_(2)O 1(ox=oxalate;bib=1,4-bis(imidazole-1-yl)benzene)has been successfully synthesized under hydrothermal condition and characterized by single crystal X-ray crystallography,powder X-ray diffraction,thermogravimetric analysis,Fourier transform infrared(FTIR)spectroscopy,magnetic susceptibility,and heat capacity *** CoII ion is connected by oxalate ions in trans-configuration to form 1D CoII–ox–CoII spin chains,which are further separated by the long organic molecule *** magnetic susceptibility curve shows that 1 exhibits a feature of broad maximum around 29 K,indicating strong antiferromagnetic interactions with short spin–spin correlations along the spin ***,no long-range order is observed due to the negligible interchain interactions through bib ligand and weak hydrogen bonds,which is further confirmed by the heat capacity *** intrachain interaction J of−8.4 K is *** magnetic susceptibility and heat capacity results indicate that 1 exhibits a good 1D magnetism.

关键词： 1,4-bis(imidazole-1-yl)benzene antiferromagnetic cobalt chain structure oxalate

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

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：