检索结果-南通市图书馆

Current state and future perspectives of sewer networks in urban China

Frontiers of Environmental Science & Engineering 2018年第3期12卷 13-28页

作者： Dong Huang Xiuhong Liu Songzhu Jiang Hongchen Wang Junyan Wang Yuankai Zhang school of Environment & Resource Renmin University of China Beijing 100872 China Chengdu urban and rural construction Commission Chengdu 610094 China

Chinese authorities and the public have largely ignored sewer networks; however, various problems are emerging nationwide with the increase construction of new sewers. The current state of sewer network construction, administration, and maintenance in China is comprehensively reviewed in this study. Serving about 444 million people, 511,200 km of sewer lines are located in urban areas. In 2014,$7 billion was invested in sewer network construction. However, both the sewer pervasion rate and the per capita sewer length were significantly lower than those in developed countries. Sewer administrative agencies in local governments are uncoordinated. Laws, regulations, and standards are incomplete, and some practices are unscientific. The future situation of sewer maintenance is extremely grim because sewer corrosion control measures have not been launched. Moreover, inspection and rehabilitation chiefly rely on traditional approaches. In contrast, the overall market share of innovative technologies is very low owing to high cost, funds shortage, and technical limitations. Approaches such-as liner inversion cured-in-place pipe, pull-in ultraviolet light cured liners, and spiral wound lining are applied mostly in economically developed regions. According to status and problem analyses, China＇s top priority will be to conduct aggressive maintenance work in sewer networks in the future. New technical route, corrosion control - periodic visualized inspection - trenchless rehabilitation, could be the best option for future sewer maintenance in China. Instmctions and opportunities for applying this technical route are discussed in detail in this study. *** factors in the development of sewer networks in China are suggested.

关键词： Sewer network China Management Sewer corrosion Sewer inspection Trenchless rehabilitation

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

Development of TD-BEM Formulation for Dynamic Analysis for Twin-Parallel Circular Tunnels in an Elastic Semi-Innite Medium

引用

Computer Modeling in Engineering & Sciences 2021年第2期126卷 577-597页

作者： Weidong Lei Hai Zhou Hongjun Li Rui Chen school of Civil and Environmental Engineering Harbin Institute of TechnologyShenzhen518055China urban and rural construction Institute Hebei Agricultural UniversityBaoding071001China

In order to simulate the propagation process of subway vibration of parallel tunnels in semi-infinite rocks or soils,time domain boundary element method(TD-BEM)formulation for analyzing the dynamic response of twin-parallel circular tunnels in an elastic semi-infinite medium is developed in this *** time domain boundary integral equations of displacement and stress for the elastodynamic problem are presented based on Betti’s reciprocal work theorem,ignoring contributions from initial conditions and body *** the process of establishing time domain boundary integral equations,some virtual boundaries are constructed between finite boundaries and the free boundary to form a boundary to refer to the time domain boundary integral equations for a single circular tunnel under dynamic *** numerical treatment and solving process of time domain boundary integral equations are given in detail,including temporal discretization,spatial discretization and the assembly of the influencing *** the process of the numerical implementation,infinite boundary elements are incorporated in time domain boundary element method formulation to satisfy stress free conditions on the ground surface,in addition,to reduce the discretization of the boundary of the ground *** applicability and efficiency of the presented time domain boundary element formulation are verified by a deliberately designed example.

关键词： Time-domain boundary element method twin-parallel tunnels innite boundary elements elastic semiinnite medium

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

Collaborative representation with background purification and saliency weight for hyperspectral anomaly detection

引用

Science China(Information Sciences) 2022年第1期65卷 247-258页

作者： Zengfu HOU Wei LI Ran TAO Pengge MA Weihua SHI school of Information and Electronics Beijing Institute of Technology school of Intelligent Engineering Zhengzhou University of Aeronautics urban-rural Planning Administration Center Ministry of Housing and Urban-Rural Development of the People's Republic of China

Collaborative representation-based detection(CRD) has been developed in hyperspectral anomaly detection tasks and testified to be very effective; however, heterogeneous pixels in the background may affect the accuracy of linear representation and make its performance suboptimal. To address this issue, a background purification framework based on linear representation is proposed, in which an automatic outlier removal strategy based on initial coefficients is designed to purify the background. In the proposed method, the classic least squares technique is firstly adopted to obtain preliminary linear representation coefficients, which are positively correlated with its contribution to a central testing pixel. Then, using statistical analysis of the representation coefficients, purified background pixels are obtained. Furthermore, a saliency weight is applied to fully utilize the spatial information of inner window pixels. Extensive experiments with three real hyperspectral datasets show that the proposed method outperforms state-of-the-art CRD and other traditional detectors.

关键词： hyperspectral anomaly detection background purification collaborative representation saliency weight

来源：

同方期刊数据库

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

Environment-friendly waterborne resin composite modified emulsified asphalt fog seal materials: Design optimization and property control

引用

Journal of Traffic and Transportation Engineering(English Edition) 2024年

作者： Qian Chen Chang Han Yanwei Li Lei Feng Zhentong Fan Songyuan Tan Chaohui Wang school of Highway， Chang'an University Taihang urban and rural construction Group Co.， Ltd

The purpose is to solve the problems of poor adhesion， low penetration capacity， and insufficient durability of ordinary emulsified asphalt fog seal materials. Waterborne epoxy resin (WER)， waterborne polyurethane (WPU)， waterborne acrylate (WA)， and styrene-butadiene rubber (SBR) were used as raw materials. A series of waterborne resin modifiers were synthesized， such as waterborne epoxy resin-reinforced polyurethane (WER-WPU)， waterborne epoxy resin-reinforced acrylate (WER-WA)， waterborne epoxy resin-reinforced styrene-butadiene rubber (WER-SBR)， waterborne polyurethane-modified styrene-butadiene rubber (WPU-SBR)， waterborne polyurethane-reinforced acrylate (WPU-WA)， waterborne epoxy resin-reinforced polyurethane-modified styrene-butadiene rubber (WER-WPU-SBR)， waterborne epoxy resin-reinforced polyurethane-modified acrylate (WER-WPU-WA). The basic properties of modified emulsified asphalt fog seal materials were comparatively evaluated with different modifier types and dosages. The optimal material composition and the proportioning scheme were determined. Thermo-oxidative aging and climatic aging were simulated. The aging resistance property of modified emulsified asphalt fog seal materials at different exposure times was clarified. The modification mechanism of emulsified asphalt fog seal material was revealed. And its pavement performance was verified. The results indicate that WER-WPU modifier and WER-WPU-SBR modifier have obvious comprehensive properties. Their appropriate doses are 15% and 20%， respectively. The terminal drying time of modified emulsified asphalt is 60-75 min， the penetration depth of standard sand is about 6 mm， and the bond strength is 1.0-1.6 MPa. The modified emulsified asphalt exhibits significant light aging resistance， and its strength retention rate is more than 80% after being exposed to thermo-oxygen aging and xenon lamp aging environments for 160 h. The modifier is uniformly distributed in emulsified asphalt and has significant c

关键词：

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

Underwater Acoustic Signal Noise Reduction Based on a Fully Convolutional Encoder-Decoder Neural Network

引用

Journal of Ocean University of China 2023年第6期22卷 1487-1496页

作者： SONG Yongqiang CHU Qian LIU Feng WANG Tao SHEN Tongsheng PLA Academy of Military Science Beijing 100089China PLA National Innovation Institute of Defense Technology Beijing 100071China Yantai urban and rural construction school Yantai 264000China

Noise reduction analysis of signals is essential for modern underwater acoustic detection *** traditional noise reduction techniques gradually lose efficacy because the target signal is masked by biological and natural noise in the marine *** feature extraction method combining time-frequency spectrograms and deep learning can effectively achieve the separation of noise and target signals.A fully convolutional encoder-decoder neural network(FCEDN)is proposed to address the issue of noise reduc-tion in underwater acoustic *** time-domain waveform map of underwater acoustic signals is converted into a wavelet low-frequency analysis recording spectrogram during the denoising process to preserve as many underwater acoustic signal characteristics as *** FCEDN is built to learn the spectrogram mapping between noise and target signals that can be learned at each time *** transposed convolution transforms are introduced,which can transform the spectrogram features of the signals into listenable audio *** evaluating the systems on the ShipsEar Dataset,the proposed method can increase SNR and SI-SNR by 10.02 and 9.5dB,re-spectively.

关键词： deep learning convolutional encoder-decoder neural network wavelet low-frequency analysis recording spectrogram

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

Energy consumption,indoor environmental quality,and benchmark for office buildings in Hainan Province of China

引用

Journal of Central South University 2012年第3期19卷 783-790页

作者：孔祥飞吕石磊辛亚娟吴薇 school of Environmental Science and Technology Tianjin University Department of Housing and urban-rural Development of Hainan

With rapid economy growth,building energy consumption in China has been gradually *** energy consumption and indoor environmental quality of 51 office buildings in Hainan Province,a hot and humid area,were studied through collection of verified data in site visits and field *** result revealed that,electricity accounted for 99.79% of the total energy consumption,natural gas 0.17%,and diesel 0.04%.The air conditioning dominated the energy use with a share of 43.18%,equipment in the particular areas 26.90%,equipment in the office rooms 11.95%,lighting system 8.67%,general service system 7.57%,and miscellaneous items 1.73%.Statistical method including six indicators obtained the energy consumption benchmark with upper limit of 98.31 kW-h/m2 and lower limit of 55.26 kW-h/*** to ASHRAE standard(comfortable standard) and GB/T 18883-2002(acceptable standard),the indoor environmental quality of 51 sampled office buildings was classified into three ranks:good,normal and *** benchmark of building energy consumption combined with indoor environmental quality,it was found that only 3.92% of sampled buildings can be identified as the best performance buildings with low energy consumption and advanced indoor environmental quality,and the buildings classified into normal level accounted for the maximum ratio.

关键词： building energy consumption benchmark indoor environmental quality energy use index Hainan Province

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

Efficient secure and verifiable KNN set similarity search over outsourced clouds

引用

High-Confidence Computing 2023年第1期3卷 38-46页

作者： Xufeng Jiang Lu Li Foundation Department Jiangsu Urban and Rural Construction CollegeChangzhou 213000China school of Information Engineering Yancheng Teachers University and Laboratory of Cyberspace SecurityYancheng 224000China

KNN set similarity search is a foundational operation in various realistic applications in cloud ***,for security consideration,sensitive data will always be encrypted before uploading to the cloud servers,which makes the search processing a challenging *** this paper,we focus on the problem of KNN set similarity search over the encrypted *** use Yao’s garbled circuits and secret sharing as underlying *** achieve better querying efficiency,we construct a secure R-Tree index structure based on a novel secure grouping protocol,which enables grouping appropriate private values in an oblivious *** with several elaborately designed secure arithmetic subroutines,we propose an efficient secure and verifiable KNN set similarity search framework over outsourced ***,we analyze the complexity of our schemes in detail,and prove the security in the presence of semi-honest ***,we evaluate the performance and feasibility of our proposed methods by extensive experiments.

关键词： Privacy preservation KNN set similarity search Yao’s garbled circuits Cloud computing

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

INVARIANT SUB-MANIFOLDS AND MODES OF NONLINEAR AUTONOMOUS SYSTEMS

引用

Applied Mathematics and Mechanics(English Edition) 1998年第7期19卷 687-693页

作者：赵国景魏建国 Peking Graduate school China University of Mining and Technology 100083 Beijing P.R. China College of urban and rural construction Agricultural University of Hebei 071001 Baoding P.R. China

A definition of the modes of a nonlinear autonomous system was developed. The existence conditions and orbits' nature of modes are given by using the geometry theory of invariant manifolds that include stable manifold theorem, center maifold theorm and sub-center manifold theorem. The Taylor series expansion was used in order to approach the sub-manifolds of the modes and obtain the motions of the mods on the manifolds. Two examples were given to demonstrate the applications.

关键词： invariant manifold mode nonlinear system

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 model of surrounding rock deformation in doublecontinuous-arch tunnel based on the ABC-WNN

引用

Railway Sciences 2024年第6期3卷 717-730页

作者： Yahui Zhang Hebei urban and rural construction school ShijiazhuangChina

Purpose–The wavelet neural network(WNN)has the drawbacks of slow convergence speed and easy falling into local optima in data *** the artificial bee colony(ABC)algorithm has strong global optimization ability and fast convergence speed,it also has the drawbacks of slow speed while finding the optimal solution and weak optimization ability in the later ***/methodology/approach–This article uses an ABC algorithm to optimize the WNN and establishes an ABC-WNN analysis *** on the example of the Jinan Yuhan underground tunnel project,the deformation of the surrounding rock of the double-arch tunnel crossing the fault fracture zone is predicted and analyzed,and the analysis results are compared with the actual detection ***–The comparison results show that the predicted values of the ABC-WNN model have a high degree of fitting with the actual engineering data,with a maximum relative error of only 4.73%.On this basis,the results show that the statistical features of ABC-WNN are the lowest,with the errors at 0.566 and 0.573,compared with the single back propagation(BP)neural network model and WNN ***,it can be derived that the ABC-WNN model has higher prediction accuracy,better computational stability and faster convergence speed for ***/value–This article uses firstly the ABC-WNN for the deformation analysis of double-arch *** attempt laid the foundation for artificial intelligence prediction in deformation analysis of multiarch tunnels and small clearance *** can provide a new and effective way for deformation prediction in similar projects.

关键词： Double arch tunnel Deformation prediction Artificial bee colonies Surrounding rock Wavelet neural network

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

A pH-universal ORR catalyst with atomic Fe-heteroatom(N,S)sites for high-performance Zn-air batteries

引用

Nano Research 2023年第7期16卷 9416-9425页

作者： Le Li Na Li Jia-Wei Xia Shi-Long Zhou Xing-Yue Qian Feng-Xiang Yin Guo-Hong Dai Guang-Yu He Hai-Qun Chen Key Laboratory of Advanced Catalytic Materials and Technology Advanced Catalysis and Green Manufacturing Collaborative Innovation CenterSchool of Petrochemical EngineeringChangzhou UniversityChangzhou 213164China Jiangsu urban and rural construction Vocational College Changzhou 213147China

Developing innovative,easy-to-manufacture,and non-Pt-group-metal(non-PGM)electrocatalysts is essential for the highly efficient oxygen reduction reaction(ORR).Herein,we report a self-sacrificing post-synthetic strategy to synthesize highly loaded Fe-isolated single atoms anchored on the hierarchical porous N,S co-doped carbon matrix(Fe-SAs/S,N-C/rGO).The optimized Fe-SAs/S,N-C/rGO exhibits excellent ORR activity in the pH-universal range with half-wave potentials of 0.89,0.80,and 0.60 V in alkaline,acidic,and neutral media,comparable to the commercial Pt/C(0.85,0.81,and 0.64 V,respectively).The homemade liquid Zn-air battery(ZAB)with Fe-SAs/S,N-C/rGO as the cathode catalyst displays an open-circuit voltage(OCV)of~1.61 V,discharging specific capacity of 817.23 mAh·g^(-1),and long-term durability of~1865 cycles,outperforming those of the device with commercial Pt/C+RuO_(2)(1.49 V,657.32 mAh·g^(-1),and~120 cycles,respectively).Intriguingly,the corresponding flexible solidstate ZAB delivers satisfactory OCV,peak power density,foldability,and cycling stability at room temperature,as well as adaptability at a low temperature of -10℃.Besides,density functional theory(DFT)calculation reveals that the atomic FeN_(3)S moieties in Fe-SAs/S,N-C/rGO can cause charge redistribution and lower the binding strength of oxygen-containing intermediates,resulting in accelerated ORR kinetics and optimized catalytic *** work provides insights into experimental and theoretical guidance towards non-PGM electrocatalysts for efficient energy conversion.

关键词： heteroatom dopant single-atom electrocatalyst FeN_(3)S sites Zn-air battery density functional theory(DFT)study

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：